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Sample records for roll-to-roll processed polymer

  1. Upscaling of polymer solar cell fabrication using full roll-to-roll processing.

    PubMed

    Krebs, Frederik C; Tromholt, Thomas; Jørgensen, Mikkel

    2010-06-01

    Upscaling of the manufacture of polymer solar cells is detailed with emphasis on cost analysis and practical approach. The device modules were prepared using both slot-die coating and screen printing the active layers in the form of stripes that were serially connected. The stripe width was varied and the resultant performance analysed. Wider stripes give access to higher geometric fill factors and lower aperture loss while they also present larger sheet resistive losses. An optimum was found through preparation of serially connected stripes having widths of 9, 13 and 18 mm with nominal geometric fill factors (excluding bus bars) of 50, 67 and 75% respectively. In addition modules with lengths of 6, 10, 20, 22.5 and 25 cm were explored. The devices were prepared by full roll-to-roll solution processing in a web width of 305 mm and roll lengths of up to 200 m. The devices were encapsulated with a barrier material in a full roll-to-roll process using standard adhesives giving the devices excellent stability during storage and operation. The total area of processed polymer solar cell was around 60 m2 per run. The solar cells were characterised using a roll-to-roll system comprising a solar simulator and an IV-curve tracer. After characterisation the solar cell modules were cut into sheets using a sheeting machine and contacted using button contacts applied by crimping. Based on this a detailed cost analysis was made showing that it is possible to prepare complete and contacted polymer solar cell modules on this scale at an area cost of 89 euro m(-2) and an electricity cost of 8.1 euro Wp(-1). The cost analysis was separated into the manufacturing cost, materials cost and also the capital investment required for setting up a complete production plant on this scale. Even though the cost in euro Wp(-1) is comparable to the cost for electricity using existing technologies the levelized cost of electricity (LCOE) is expected to be significantly higher than the existing

  2. Aqueous processing of low-band-gap polymer solar cells using roll-to-roll methods.

    PubMed

    Andersen, Thomas R; Larsen-Olsen, Thue T; Andreasen, Birgitta; Böttiger, Arvid P L; Carlé, Jon E; Helgesen, Martin; Bundgaard, Eva; Norrman, Kion; Andreasen, Jens W; Jørgensen, Mikkel; Krebs, Frederik C

    2011-05-24

    Aqueous nanoparticle dispersions of a series of three low-band-gap polymers poly[4,8-bis(2-ethylhexyloxy)benzo(1,2-b:4,5-b')dithiophene-alt-5,6-bis(octyloxy)-4,7-di(thiophen-2-yl)(2,1,3-benzothiadiazole)-5,5'-diyl] (P1), poly[(4,4'-bis(2-ethylhexyl)dithieno[3,2-b:2',3'-d]silole)-2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl] (P2), and poly[2,3-bis-(3-octyloxyphenyl)quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl] (P3) were prepared using ultrasonic treatment of a chloroform solution of the polymer and [6,6]-phenyl-C(61)-butyric acid methyl ester ([60]PCBM) mixed with an aqueous solution of sodium dodecylsulphate (SDS). The size of the nanoparticles was established using small-angle X-ray scattering (SAXS) of the aqueous dispersions and by both atomic force microscopy (AFM) and using both grazing incidence SAXS (GISAXS) and grazing incidence wide-angle X-ray scattering (GIWAXS) in the solid state as coated films. The aqueous dispersions were dialyzed to remove excess detergent and concentrated to a solid content of approximately 60 mg mL(-1). The formation of films for solar cells using the aqueous dispersion required the addition of the nonionic detergent FSO-100 at a concentration of 5 mg mL(-1). This enabled slot-die coating of high quality films with a dry thickness of 126 ± 19, 500 ± 25, and 612 ± 22 nm P1, P2, and P3, respectively for polymer solar cells. Large area inverted polymer solar cells were thus prepared based on the aqueous inks. The power conversion efficiency (PCE) reached for each of the materials was 0.07, 0.55, and 0.15% for P1, P2, and P3, respectively. The devices were prepared using coating and printing of all layers including the metal back electrodes. All steps were carried out using roll-to-roll (R2R) slot-die and screen printing methods on flexible substrates. All five layers were processed using environmentally friendly methods and solvents. Two of the layers were processed entirely from water (the electron transport layer and the active

  3. Aqueous processing of low-band-gap polymer solar cells using roll-to-roll methods.

    PubMed

    Andersen, Thomas R; Larsen-Olsen, Thue T; Andreasen, Birgitta; Böttiger, Arvid P L; Carlé, Jon E; Helgesen, Martin; Bundgaard, Eva; Norrman, Kion; Andreasen, Jens W; Jørgensen, Mikkel; Krebs, Frederik C

    2011-05-24

    Aqueous nanoparticle dispersions of a series of three low-band-gap polymers poly[4,8-bis(2-ethylhexyloxy)benzo(1,2-b:4,5-b')dithiophene-alt-5,6-bis(octyloxy)-4,7-di(thiophen-2-yl)(2,1,3-benzothiadiazole)-5,5'-diyl] (P1), poly[(4,4'-bis(2-ethylhexyl)dithieno[3,2-b:2',3'-d]silole)-2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl] (P2), and poly[2,3-bis-(3-octyloxyphenyl)quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl] (P3) were prepared using ultrasonic treatment of a chloroform solution of the polymer and [6,6]-phenyl-C(61)-butyric acid methyl ester ([60]PCBM) mixed with an aqueous solution of sodium dodecylsulphate (SDS). The size of the nanoparticles was established using small-angle X-ray scattering (SAXS) of the aqueous dispersions and by both atomic force microscopy (AFM) and using both grazing incidence SAXS (GISAXS) and grazing incidence wide-angle X-ray scattering (GIWAXS) in the solid state as coated films. The aqueous dispersions were dialyzed to remove excess detergent and concentrated to a solid content of approximately 60 mg mL(-1). The formation of films for solar cells using the aqueous dispersion required the addition of the nonionic detergent FSO-100 at a concentration of 5 mg mL(-1). This enabled slot-die coating of high quality films with a dry thickness of 126 ± 19, 500 ± 25, and 612 ± 22 nm P1, P2, and P3, respectively for polymer solar cells. Large area inverted polymer solar cells were thus prepared based on the aqueous inks. The power conversion efficiency (PCE) reached for each of the materials was 0.07, 0.55, and 0.15% for P1, P2, and P3, respectively. The devices were prepared using coating and printing of all layers including the metal back electrodes. All steps were carried out using roll-to-roll (R2R) slot-die and screen printing methods on flexible substrates. All five layers were processed using environmentally friendly methods and solvents. Two of the layers were processed entirely from water (the electron transport layer and the active

  4. Manufacturing Demonstration Facility: Roll-to-Roll Processing

    SciTech Connect

    Datskos, Panos G; Joshi, Pooran C; List III, Frederick Alyious; Duty, Chad E; Armstrong, Beth L; Ivanov, Ilia N; Jacobs, Christopher B; Graham, David E; Moon, Ji Won

    2015-08-01

    This Manufacturing Demonstration Facility (MDF)e roll-to-roll processing effort described in this report provided an excellent opportunity to investigate a number of advanced manufacturing approaches to achieve a path for low cost devices and sensors. Critical to this effort is the ability to deposit thin films at low temperatures using nanomaterials derived from nanofermentation. The overarching goal of this project was to develop roll-to-roll manufacturing processes of thin film deposition on low-cost flexible substrates for electronics and sensor applications. This project utilized ORNL s unique Pulse Thermal Processing (PTP) technologies coupled with non-vacuum low temperature deposition techniques, ORNL s clean room facility, slot dye coating, drop casting, spin coating, screen printing and several other equipment including a Dimatix ink jet printer and a large-scale Kyocera ink jet printer. The roll-to-roll processing project had three main tasks: 1) develop and demonstrate zinc-Zn based opto-electronic sensors using low cost nanoparticulate structures manufactured in a related MDF Project using nanofermentation techniques, 2) evaluate the use of silver based conductive inks developed by project partner NovaCentrix for electronic device fabrication, and 3) demonstrate a suite of low cost printed sensors developed using non-vacuum deposition techniques which involved the integration of metal and semiconductor layers to establish a diverse sensor platform technology.

  5. Silver front electrode grids for ITO-free all printed polymer solar cells with embedded and raised topographies, prepared by thermal imprint, flexographic and inkjet roll-to-roll processes.

    PubMed

    Yu, Jong-Su; Kim, Inyoung; Kim, Jung-Su; Jo, Jeongdai; Larsen-Olsen, Thue T; Søndergaard, Roar R; Hösel, Markus; Angmo, Dechan; Jørgensen, Mikkel; Krebs, Frederik C

    2012-09-28

    Semitransparent front electrodes for polymer solar cells, that are printable and roll-to-roll processable under ambient conditions using different approaches, are explored in this report. The excellent smoothness of indium-tin-oxide (ITO) electrodes has traditionally been believed to be difficult to achieve using printed front grids, as surface topographies accumulate when processing subsequent layers, leading to shunts between the top and bottom printed metallic electrodes. Here we demonstrate how aqueous nanoparticle based silver inks can be employed as printed front electrodes using several different roll-to-roll techniques. We thus compare hexagonal silver grids prepared using either roll-to-roll inkjet or roll-to-roll flexographic printing. Both inkjet and flexo grids present a raised topography and were found to perform differently due to only the conductivity of the obtained silver grid. The raised topographies were compared with a roll-to-roll thermally imprinted grid that was filled with silver in a roll-to-roll process, thus presenting an embedded topography. The embedded grid and the flexo grid were found to perform equally well, with the flexographic technique currently presenting the fastest processing and the lowest silver use, whereas the embedded grid presents the maximally achievable optical transparency and conductivity. Polymer solar cells were prepared in the same step, using roll-to-roll slot-die coating of zinc oxide as the electron transport layer, poly-3-hexylthiophene:phenyl-C(61)-butyric acid methyl ester (P3HT:PCBM) as the active layer and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the top electrode, along with a flat bed screen printed silver grid. The power conversion efficiency (PCE) obtained for large area devices (6 cm(2)) was 1.84%, 0.79% and 1.72%, respectively, for thermally imprinted, inkjet and flexographic silver grids, tested outside under the real sun. Central to all three approaches was that they

  6. Silver front electrode grids for ITO-free all printed polymer solar cells with embedded and raised topographies, prepared by thermal imprint, flexographic and inkjet roll-to-roll processes.

    PubMed

    Yu, Jong-Su; Kim, Inyoung; Kim, Jung-Su; Jo, Jeongdai; Larsen-Olsen, Thue T; Søndergaard, Roar R; Hösel, Markus; Angmo, Dechan; Jørgensen, Mikkel; Krebs, Frederik C

    2012-09-28

    Semitransparent front electrodes for polymer solar cells, that are printable and roll-to-roll processable under ambient conditions using different approaches, are explored in this report. The excellent smoothness of indium-tin-oxide (ITO) electrodes has traditionally been believed to be difficult to achieve using printed front grids, as surface topographies accumulate when processing subsequent layers, leading to shunts between the top and bottom printed metallic electrodes. Here we demonstrate how aqueous nanoparticle based silver inks can be employed as printed front electrodes using several different roll-to-roll techniques. We thus compare hexagonal silver grids prepared using either roll-to-roll inkjet or roll-to-roll flexographic printing. Both inkjet and flexo grids present a raised topography and were found to perform differently due to only the conductivity of the obtained silver grid. The raised topographies were compared with a roll-to-roll thermally imprinted grid that was filled with silver in a roll-to-roll process, thus presenting an embedded topography. The embedded grid and the flexo grid were found to perform equally well, with the flexographic technique currently presenting the fastest processing and the lowest silver use, whereas the embedded grid presents the maximally achievable optical transparency and conductivity. Polymer solar cells were prepared in the same step, using roll-to-roll slot-die coating of zinc oxide as the electron transport layer, poly-3-hexylthiophene:phenyl-C(61)-butyric acid methyl ester (P3HT:PCBM) as the active layer and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the top electrode, along with a flat bed screen printed silver grid. The power conversion efficiency (PCE) obtained for large area devices (6 cm(2)) was 1.84%, 0.79% and 1.72%, respectively, for thermally imprinted, inkjet and flexographic silver grids, tested outside under the real sun. Central to all three approaches was that they

  7. Investigation of pattern transfer to piezoelectric jetted polymer using roll-to-roll nanoimprint lithography

    NASA Astrophysics Data System (ADS)

    Menezes, Shannon John

    Nanoimprint Lithography (NIL) has existed since the mid 1990s as a proven concept of creating micro- and nanostructures using direct mechanical pattern transfer. Initially seen as a viable option to replace conventional lithography methods, the lack of technology to support large-scale manufacturing using NIL has motivated researchers to explore the application of NIL to create a better, more cost-efficient process with the ability to integrate NIL into a mass manufacturing system. One such method is the roll-to-roll process, similar to that used in printing presses of newspapers and plastics. This thesis is an investigation to characterize polymer deposition using a piezoelectric jetting head and attempt to create micro- and nanostructures on the polymer using R2RNIL technique.

  8. Roll-to-roll embossing of optical linear Fresnel lens polymer film for solar concentration.

    PubMed

    Zhang, XinQuan; Liu, Kui; Shan, Xuechuan; Liu, Yuchan

    2014-12-15

    Roll-to-roll manufacturing has been proven to be a high-throughput and low-cost technology for continuous fabrication of functional optical polymer films. In this paper, we have firstly studied a complete manufacturing cycle of linear Fresnel lens polymer film for solar concentration in the aspects of ultra-precision diamond machining of metal roller mold, roll-to-roll embossing, and measurement on film profile and functionality. A metal roller mold patterned with linear Fresnel lenses is obtained using single point diamond turning technique. The roller mold is installed onto a self-developed roll-to-roll UV embossing system to realize continuous manufacturing of linear Fresnel lens film. Profile measurement of the machined roller mold and the embossed polymer film, which is conducted using a stylus profilometer, shows good agreement between measured facet angles with designed ones. Functionality test is conducted on a solar simulation system with a reference solar cell, and results show that strong light concentration is realized.

  9. Thermoresistive strain sensor and positioning method for roll-to-roll processes.

    PubMed

    Liao, Kuan-Hsun; Lo, Cheng-Yao

    2014-01-01

    This study uses the Joule heating effect-generated temperature difference to monitor in real-time and localize both compressive and tensile strains for the polymer substrates used in the roll-to-roll process. A serpentine gold (Au) line was patterned on a polyethylenenaphthalate (PEN) substrate to form the strain sensor based on thermoresistive behavior. This strain sensor was then subjected to either current or voltage to induce the Joule heating effect on the Au resistor. An infrared (IR) detector was used to monitor the strain-induced temperature difference on the Au and PEN surfaces and the minimal detectable bending radius was 0.9 mm with a gauge factor (GF) of 1.46. The proposed design eliminates the judgment ambiguity from conventional resistive strain sensors where resistance is the only physical quantity monitored. This study precisely and successfully indicated the local strain quantitatively and qualitatively with complete simulations and measurements. PMID:24803196

  10. Development of a continuous roll-to-roll processing system for mass production of plastic optical film

    NASA Astrophysics Data System (ADS)

    Chang, Chih-Yuan; Tsai, Meng-Hsun

    2015-12-01

    This paper reports a highly effective method for the mass production of large-area plastic optical films with a microlens array pattern based on a continuous roll-to-roll film extrusion and roller embossing process. In this study, a thin steel mold with a micro-circular hole array pattern is fabricated by photolithography and a wet chemical etching process. The thin steel mold was then wrapped onto a metal cylinder to form an embossing roller mold. During the roll-to-roll process operation, a thermoplastic raw material (polycarbonate grains) was put into the barrel of the plastic extruder with a flat T-die. Then, the molten polymer film was extruded and immediately pressed against the surface of the embossing roller mold. Under the proper processing conditions, the molten polymer will just partially fill the micro-circular holes of the mold and due to surface tension form a convex lens surface. A continuous plastic optical film with a microlens array pattern was obtained. Experiments are carried out to investigate the effect of plastic microlens formation on the roll-to-roll process. Finally, the geometrical and optical properties of the fabricated plastic optical film were measured and proved satisfactory. This technique shows great potential for the mass production of large-area plastic optical films with a microlens array pattern.

  11. Laser processing of organic photovoltaic cells with a roll-to-roll manufacturing process

    NASA Astrophysics Data System (ADS)

    Petsch, Tino; Haenel, Jens; Clair, Maurice; Keiper, Bernd; Scholz, Christian

    2011-03-01

    Flexible large area organic photovoltaic (OPV) is currently one of the fastest developing areas of organic electronics. New light absorbing polymer blends combined with new transparent conductive materials provide higher power conversion efficiencies while new and improved production methods are developed to achieve higher throughput at reduced cost. A typical OPV is formed by TCO layers as the transparent front contact and polymers as active layer as well as interface layer between active layer and front contact. The several materials have to be patterned in order to allow for a row connection of the solar cell. 3D-Micromac used ultra-short pulsed lasers to evaluate the applicability of various wavelengths for the selective ablation of the indium tin oxide (ITO) layer and the selective ablation of the bulk hetero junction (BHJ) consisting of poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester (P3HT:PCBM) on top of a Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) without damaging the ITO. These lasers in combination with high performance galvanometer scanning systems achieve superior scribing quality without damaging the substrate. With scribing speeds of 10 m/s and up it is possible to integrate this technology into a roll-to-roll manufacturing tool. The functionality of an OPV usually also requires an annealing step, especially when using a BHJ for the active layer consisting of P3HT:PCBM, to optimize the layers structure and therewith the efficiency of the solar cell (typically by thermal treatment, e.g. oven). The process of laser annealing was investigated using a short-pulsed laser with a wavelength close to the absorption maximum of the BHJ.

  12. Roll-to-roll atomic layer deposition process for flexible electronics encapsulation applications

    SciTech Connect

    Maydannik, Philipp S. Kääriäinen, Tommi O.; Lahtinen, Kimmo; Cameron, David C.; Söderlund, Mikko; Soininen, Pekka; Johansson, Petri; Kuusipalo, Jurkka; Moro, Lorenza; Zeng, Xianghui

    2014-09-01

    At present flexible electronic devices are under extensive development and, among them, flexible organic light-emitting diode displays are the closest to a large market deployment. One of the remaining unsolved challenges is high throughput production of impermeable flexible transparent barrier layers that protect sensitive light-emitting materials against ambient moisture. The present studies deal with the adaptation of the atomic layer deposition (ALD) process to high-throughput roll-to-roll production using the spatial ALD concept. We report the development of such a process for the deposition of 20 nm thickness Al{sub 2}O{sub 3} diffusion barrier layers on 500 mm wide polymer webs. The process uses trimethylaluminum and water as precursors at a substrate temperature of 105 °C. The observation of self-limiting film growth behavior and uniformity of thickness confirms the ALD growth mechanism. Water vapor transmission rates for 20 nm Al{sub 2}O{sub 3} films deposited on polyethylene naphthalate (PEN) substrates were measured as a function of substrate residence time, that is, time of exposure of the substrate to one precursor zone. Moisture permeation levels measured at 38 °C/90% relative humidity by coulometric isostatic–isobaric method were below the detection limit of the instrument (<5 × 10{sup −4} g/m{sup 2} day) for films coated at web moving speed of 0.25 m/min. Measurements using the Ca test indicated water vapor transmission rates ∼5 × 10{sup −6} g/m{sup 2} day. Optical measurements on the coated web showed minimum transmission of 80% in the visible range that is the same as the original PEN substrate.

  13. Develop Roll-to-Roll Manufacturing Process of ZrO2 Nanocrystals/Acrylic Nanocomposites for High Refractive Index Applications

    SciTech Connect

    Joshi, Pooran C.; Compton, Brett G.; Li, Jianlin; Jellison, Jr, Gerald Earle; Duty, Chad E; Chen, Zhiyun

    2015-04-01

    The purpose of this Cooperative Research and Development Agreement (CRADA) was to develop and evaluate ZrO2/acrylic nanocomposite coatings for integrated optoelectronic applications. The formulations engineered to be compatible with roll-to-roll process were evaluated in terms of optical and dielectric properties. The uniform distribution of the ZrO2 nanocrystals in the polymer matrix resulted in highly tunable refractive index and dielectric response suitable for advanced photonic and electronic device applications.

  14. In situ monitoring of structure formation in the active layer of polymer solar cells during roll-to-roll coating

    NASA Astrophysics Data System (ADS)

    Rossander, Lea H.; Zawacka, Natalia K.; Dam, Henrik F.; Krebs, Frederik C.; Andreasen, Jens W.

    2014-08-01

    The active layer crystallization during roll-to-roll coating of organic solar cells is studied in situ. We developed an X-ray setup where the coater unit is an integrated part of the small angle X-ray scattering instrument, making it possible to control the coating process while recording scattering measurements in situ, enabling us to follow the crystal formation during drying. By varying the distance between the coating head and the point where the X-ray beam hits the film, we obtained measurements of 4 different stages of drying. For each of those stages, the scattering from as long a foil as possible is summed together, with the distance from coating head to scattering point kept constant. The results are average crystallographic properties for the active layer coated on a 30 m long foil. With this insight into the dynamics of crystallization in a roll-coated polymer film, we find that the formation of textured and untextured crystallites seems uncorrelated, and happens at widely different rates. Untextured P3HT crystallites form later in the drying process than expected which may explain previous studies speculating that untextured crystallization depends on concentration. Textured crystallites, however, begin forming much earlier and steadily increases as the film dries, showing a development similar to other in situ studies of these materials.

  15. In situ monitoring of structure formation in the active layer of polymer solar cells during roll-to-roll coating

    SciTech Connect

    Rossander, Lea H.; Zawacka, Natalia K.; Dam, Henrik F.; Krebs, Frederik C.; Andreasen, Jens W.

    2014-08-15

    The active layer crystallization during roll-to-roll coating of organic solar cells is studied in situ. We developed an X-ray setup where the coater unit is an integrated part of the small angle X-ray scattering instrument, making it possible to control the coating process while recording scattering measurements in situ, enabling us to follow the crystal formation during drying. By varying the distance between the coating head and the point where the X-ray beam hits the film, we obtained measurements of 4 different stages of drying. For each of those stages, the scattering from as long a foil as possible is summed together, with the distance from coating head to scattering point kept constant. The results are average crystallographic properties for the active layer coated on a 30 m long foil. With this insight into the dynamics of crystallization in a roll-coated polymer film, we find that the formation of textured and untextured crystallites seems uncorrelated, and happens at widely different rates. Untextured P3HT crystallites form later in the drying process than expected which may explain previous studies speculating that untextured crystallization depends on concentration. Textured crystallites, however, begin forming much earlier and steadily increases as the film dries, showing a development similar to other in situ studies of these materials.

  16. Roll-to-Roll Solution-Processible Small-Molecule OLEDs

    SciTech Connect

    Liu, Jie Jerry

    2012-07-31

    The objective of this program is to develop key knowledge and make critical connections between technologies needed to enable low-cost manufacturing of OLED lighting products. In particular, the program was intended to demonstrate the feasibility of making high performance Small-Molecule OLEDs (SM-OLED) using a roll-to-roll (R2R) wet-coating technique by addressing the following technical risks (1) Whether the wet-coating technique can provide high performance OLEDs, (2) Whether SM-OLED can be made in a R2R manner, (3) What are the requirements for coating equipment, and (4) Whether R2R OLEDs can have the same performance as the lab controls. The program has been managed and executed according to the Program Management Plan (PMP) that was first developed at the beginning of the program and further revised accordingly as the program progressed. Significant progress and risk reductions have been accomplished by the end of the program. Specific achievements include: (1) Demonstrated that wet-coating can provide OLEDs with high LPW and long lifetime; (2) Demonstrated R2R OLEDs can be as efficient as batch controls (Figure 1) (3) Developed & validated basic designs for key equipment necessary for R2R SM-OLEDs; (4) Developed know-hows & specifications on materials & ink formulations critical to wetcoating; (5) Developed key R2R processes for each OLED layer (6) Identified key materials and components such as flexible barrier substrates necessary for R2R OLEDs.

  17. Characterization of printed planar electromagnetic coils using digital extrusion and roll-to-roll flexographic processes

    NASA Astrophysics Data System (ADS)

    Rickard, Scott

    Electromagnets are a crucial component in a wide range of more complex electrical devices due to their ability to turn electrical energy into mechanical energy and vice versa. The trend for electronics becoming smaller and lighter has led to increased interest in using flat, planar electromagnetic coils, which have been shown to perform better at scaled down sizes. The two-dimensional geometry of a planar electromagnetic coil yields itself to be produced by a roll-to-roll additive manufacturing process. The emergence of the printed electronics field, which uses traditional printing processes to pattern functional inks, has led to new methods of mass-producing basic electrical components. The ability to print a planar electromagnetic coil using printed electronics could rival the traditional subtractive and semi-subtractive PCB process of manufacturing. The ability to print lightweight planar electromagnetic coils on flexible substrates could lead to their inclusion into intelligent packaging applications and could have specific use in actuating devices, transformers, and electromagnetic induction applications such as energy harvesting or wireless charging. In attempts to better understand the limitations of printing planar electromagnetic coils, the effect that the design parameters of the planar coils have on the achievable magnetic field strength were researched. A comparison between prototyping methods of digital extrusion and manufacturing scale flexographic printing are presented, discussing consistency in the printed coils and their performance in generating magnetic fields. A method to predict the performance of these planar coils is introduced to allow for design within required needs of an application. Results from the research include a demonstration of a printed coil being used in a flat speaker design, working off of actuating principles.

  18. Roll to Roll Electric Field "Z" Alignment of Nanoparticles from Polymer Solutions for Manufacturing Multifunctional Capacitor Films.

    PubMed

    Guo, Yuanhao; Batra, Saurabh; Chen, Yuwei; Wang, Enmin; Cakmak, Miko

    2016-07-20

    A roll to roll continuous processing method is developed for vertical alignment ("Z" alignment) of barium titanate (BaTiO3) nanoparticle columns in polystyrene (PS)/toluene solutions. This is accomplished by applying an electric field to a two-layer solution film cast on a carrier: one is the top sacrificial layer contacting the electrode and the second is the polymer solution dispersed with BaTiO3 particles. Flexible Teflon coated mesh is utilized as the top electrode that allows the evaporation of solvent through the openings. The kinetics of particle alignment and chain buckling is studied by the custom-built instrument measuring the real time optical light transmission during electric field application and drying steps. The nanoparticles dispersed in the composite bottom layer form chains due to dipole-dipole interaction under an applied electric field. In relatively weak electric fields, the particle chain axis tilts away from electric field direction due to bending caused by the shrinkage of the film during drying. The use of strong electric fields leads to maintenance of alignment of particle chains parallel to the electric field direction overcoming the compression effect. At the end of the process, the surface features of the top porous electrodes are imprinted at the top of the top sacrificial layer. By removing this layer a smooth surface film is obtained. The nanocomposite films with "Z" direction alignment of BaTiO3 particles show substantially increased dielectric permittivity in the thickness direction for enhancing the performance of capacitors. PMID:27322765

  19. Roll to Roll Electric Field "Z" Alignment of Nanoparticles from Polymer Solutions for Manufacturing Multifunctional Capacitor Films.

    PubMed

    Guo, Yuanhao; Batra, Saurabh; Chen, Yuwei; Wang, Enmin; Cakmak, Miko

    2016-07-20

    A roll to roll continuous processing method is developed for vertical alignment ("Z" alignment) of barium titanate (BaTiO3) nanoparticle columns in polystyrene (PS)/toluene solutions. This is accomplished by applying an electric field to a two-layer solution film cast on a carrier: one is the top sacrificial layer contacting the electrode and the second is the polymer solution dispersed with BaTiO3 particles. Flexible Teflon coated mesh is utilized as the top electrode that allows the evaporation of solvent through the openings. The kinetics of particle alignment and chain buckling is studied by the custom-built instrument measuring the real time optical light transmission during electric field application and drying steps. The nanoparticles dispersed in the composite bottom layer form chains due to dipole-dipole interaction under an applied electric field. In relatively weak electric fields, the particle chain axis tilts away from electric field direction due to bending caused by the shrinkage of the film during drying. The use of strong electric fields leads to maintenance of alignment of particle chains parallel to the electric field direction overcoming the compression effect. At the end of the process, the surface features of the top porous electrodes are imprinted at the top of the top sacrificial layer. By removing this layer a smooth surface film is obtained. The nanocomposite films with "Z" direction alignment of BaTiO3 particles show substantially increased dielectric permittivity in the thickness direction for enhancing the performance of capacitors.

  20. Fabrication of microlens arrays on a glass substrate by roll-to-roll process with PDMS mold

    NASA Astrophysics Data System (ADS)

    Hu, Chia-Nying; Su, Guo-Dung J.

    2009-08-01

    This paper presents a roll-to-roll method to fabricate microlens arrays on a glass substrate by using a cost-effective PDMS (Polydimethylsiloxane) mold. We fabricated microlens arrays mold, which was made by photoresist(AZ4620), on the silicon substrate by thermal reflow process, and transferred the pattern to PDMS film. Roll-to-roll system is a standard printing process whose roller is made of acrylic cylinder surrounded with the PDMS mold. UV resin was chosen to be the material to make microlens in rolling process with UV light curing. We investigated the quality of microlens arrays by changing the parameters, such as embossing pressure and rolling speed, to ensure good quality of microlens arrays.

  1. Waveguide slot-excited long racetrack electron cyclotron resonance plasma source for roll-to-roll (scanning) processing

    SciTech Connect

    You, H.-J.

    2013-07-15

    We present a SLot-excited ANtenna (SLAN) long racetrack ECR plasma source that is utilized for roll-to-roll plasma processing such as thin film encapsulation of large-area OLED (organic light emitting diode) panel or modification of fabric surfaces. This source is designed to be long, and to operate under high density uniform plasma with sub-milli-torr pressures. The above features are accomplished by a slot-excited long racetrack resonator with a toroidal geometry of magnetic field ECR configuration, and reinforced microwave electric distributions along the central region of plasma chamber. Also, a new feature has been added to the source. This is to employ a tail plunger, which allows the microwave electric field and the uniformity of the plasma profile to be easily adjustable. We have successfully generated Ar plasmas operating with the microwave power of 0.5–3 kW in the pressure range of 0.2–10 mTorr. The plasma is uniform (<10%) in the direction of the straight track and has a Gaussian profile in the roll-to-roll (scanning) direction. In addition, it is shown that the tail plunger could adjust the plasma profile in order to obtain plasma uniformity. Furthermore, based on the results, we suggest a newly designed up-scaled racetrack-SLAN source.

  2. Waveguide slot-excited long racetrack electron cyclotron resonance plasma source for roll-to-roll (scanning) processing.

    PubMed

    You, H-J

    2013-07-01

    We present a SLot-excited ANtenna (SLAN) long racetrack ECR plasma source that is utilized for roll-to-roll plasma processing such as thin film encapsulation of large-area OLED (organic light emitting diode) panel or modification of fabric surfaces. This source is designed to be long, and to operate under high density uniform plasma with sub-milli-torr pressures. The above features are accomplished by a slot-excited long racetrack resonator with a toroidal geometry of magnetic field ECR configuration, and reinforced microwave electric distributions along the central region of plasma chamber. Also, a new feature has been added to the source. This is to employ a tail plunger, which allows the microwave electric field and the uniformity of the plasma profile to be easily adjustable. We have successfully generated Ar plasmas operating with the microwave power of 0.5-3 kW in the pressure range of 0.2-10 mTorr. The plasma is uniform (<10%) in the direction of the straight track and has a Gaussian profile in the roll-to-roll (scanning) direction. In addition, it is shown that the tail plunger could adjust the plasma profile in order to obtain plasma uniformity. Furthermore, based on the results, we suggest a newly designed up-scaled racetrack-SLAN source.

  3. Waveguide slot-excited long racetrack electron cyclotron resonance plasma source for roll-to-roll (scanning) processing

    NASA Astrophysics Data System (ADS)

    You, H.-J.

    2013-07-01

    We present a SLot-excited ANtenna (SLAN) long racetrack ECR plasma source that is utilized for roll-to-roll plasma processing such as thin film encapsulation of large-area OLED (organic light emitting diode) panel or modification of fabric surfaces. This source is designed to be long, and to operate under high density uniform plasma with sub-milli-torr pressures. The above features are accomplished by a slot-excited long racetrack resonator with a toroidal geometry of magnetic field ECR configuration, and reinforced microwave electric distributions along the central region of plasma chamber. Also, a new feature has been added to the source. This is to employ a tail plunger, which allows the microwave electric field and the uniformity of the plasma profile to be easily adjustable. We have successfully generated Ar plasmas operating with the microwave power of 0.5-3 kW in the pressure range of 0.2-10 mTorr. The plasma is uniform (<10%) in the direction of the straight track and has a Gaussian profile in the roll-to-roll (scanning) direction. In addition, it is shown that the tail plunger could adjust the plasma profile in order to obtain plasma uniformity. Furthermore, based on the results, we suggest a newly designed up-scaled racetrack-SLAN source.

  4. Waveguide slot-excited long racetrack electron cyclotron resonance plasma source for roll-to-roll (scanning) processing.

    PubMed

    You, H-J

    2013-07-01

    We present a SLot-excited ANtenna (SLAN) long racetrack ECR plasma source that is utilized for roll-to-roll plasma processing such as thin film encapsulation of large-area OLED (organic light emitting diode) panel or modification of fabric surfaces. This source is designed to be long, and to operate under high density uniform plasma with sub-milli-torr pressures. The above features are accomplished by a slot-excited long racetrack resonator with a toroidal geometry of magnetic field ECR configuration, and reinforced microwave electric distributions along the central region of plasma chamber. Also, a new feature has been added to the source. This is to employ a tail plunger, which allows the microwave electric field and the uniformity of the plasma profile to be easily adjustable. We have successfully generated Ar plasmas operating with the microwave power of 0.5-3 kW in the pressure range of 0.2-10 mTorr. The plasma is uniform (<10%) in the direction of the straight track and has a Gaussian profile in the roll-to-roll (scanning) direction. In addition, it is shown that the tail plunger could adjust the plasma profile in order to obtain plasma uniformity. Furthermore, based on the results, we suggest a newly designed up-scaled racetrack-SLAN source. PMID:23902069

  5. The prospects of design for roll to roll lithography: layout refinement utilizing process simulation

    NASA Astrophysics Data System (ADS)

    Kobayashi, Sachiko; Shimizu, Mitsuko; Tanaka, Satoshi; Furutono, Yohko; Hatano, Masayuki; Matsuki, Kazuto; Inanami, Ryoichi; Mimotogi, Shoji

    2014-03-01

    Directed self-assembly (DSA) of block copolymers (BCPs) is a promising method for producing the sub-20nm features required for future semiconductor device scaling, but many questions still surround the issue of defect levels in DSA processes. Knowledge of the free energy associated with a defect is critical to estimating the limiting equilibrium defect density that may be achievable in such a process. In this work, a coarse grained molecular dynamics (MD) model is used to study the free energy of a dislocation pair defect via thermodynamic integration. MD models with realistic potentials allow for more accurate simulations of the inherent polymer behavior without the need to guess modes of molecular movement and without oversimplifying atomic interactions. The free energy of such a defect as a function of the Flory- Huggins parameter (χ) and the total degree of polymerization (N) for the block copolymer is also calculated. It is found that high pitch multiplying underlayers do not show significant decreases in defect free energy relative to a simple pitch doubling underlayer. It is also found that χN is not the best descriptor for correlating defect free energy since simultaneous variation in chain length (N) and χ value while maintaining a constant χN product produces significantly different defect free energies. Instead, the defect free energy seems to be directly correlated to the χ value of the diblock copolymer used. This means that as higher χ systems are produced and utilized for DSA, the limiting defect level will likely decrease even though DSA processes may still operate at similar χN values to achieve ever smaller feature sizes.

  6. Overlay accuracy on a flexible web with a roll printing process based on a roll-to-roll system.

    PubMed

    Chang, Jaehyuk; Lee, Sunggun; Lee, Ki Beom; Lee, Seungjun; Cho, Young Tae; Seo, Jungwoo; Lee, Sukwon; Jo, Gugrae; Lee, Ki-yong; Kong, Hyang-Shik; Kwon, Sin

    2015-05-01

    For high-quality flexible devices from printing processes based on Roll-to-Roll (R2R) systems, overlay alignment during the patterning of each functional layer poses a major challenge. The reason is because flexible substrates have a relatively low stiffness compared with rigid substrates, and they are easily deformed during web handling in the R2R system. To achieve a high overlay accuracy for a flexible substrate, it is important not only to develop web handling modules (such as web guiding, tension control, winding, and unwinding) and a precise printing tool but also to control the synchronization of each unit in the total system. A R2R web handling system and reverse offset printing process were developed in this work, and an overlay between the 1st and 2nd layers of ±5μm on a 500 mm-wide film was achieved at a σ level of 2.4 and 2.8 (x and y directions, respectively) in a continuous R2R printing process. This paper presents the components and mechanisms used in reverse offset printing based on a R2R system and the printing results including positioning accuracy and overlay alignment accuracy.

  7. Bioinspired superhydrophobic surfaces, fabricated through simple and scalable roll-to-roll processing

    NASA Astrophysics Data System (ADS)

    Park, Sung-Hoon; Lee, Sangeui; Moreira, David; Bandaru, Prabhakar R.; Han, Intaek; Yun, Dong-Jin

    2015-10-01

    A simple, scalable, non-lithographic, technique for fabricating durable superhydrophobic (SH) surfaces, based on the fingering instabilities associated with non-Newtonian flow and shear tearing, has been developed. The high viscosity of the nanotube/elastomer paste has been exploited for the fabrication. The fabricated SH surfaces had the appearance of bristled shark skin and were robust with respect to mechanical forces. While flow instability is regarded as adverse to roll-coating processes for fabricating uniform films, we especially use the effect to create the SH surface. Along with their durability and self-cleaning capabilities, we have demonstrated drag reduction effects of the fabricated films through dynamic flow measurements.

  8. Bioinspired superhydrophobic surfaces, fabricated through simple and scalable roll-to-roll processing

    PubMed Central

    Park, Sung-Hoon; Lee, Sangeui; Moreira, David; Bandaru, Prabhakar R.; Han, InTaek; Yun, Dong-Jin

    2015-01-01

    A simple, scalable, non-lithographic, technique for fabricating durable superhydrophobic (SH) surfaces, based on the fingering instabilities associated with non-Newtonian flow and shear tearing, has been developed. The high viscosity of the nanotube/elastomer paste has been exploited for the fabrication. The fabricated SH surfaces had the appearance of bristled shark skin and were robust with respect to mechanical forces. While flow instability is regarded as adverse to roll-coating processes for fabricating uniform films, we especially use the effect to create the SH surface. Along with their durability and self-cleaning capabilities, we have demonstrated drag reduction effects of the fabricated films through dynamic flow measurements. PMID:26490133

  9. Continuous and scalable fabrication of bioinspired dry adhesives via a roll-to-roll process with modulated ultraviolet-curable resin.

    PubMed

    Yi, Hoon; Hwang, Insol; Lee, Jeong Hyeon; Lee, Dael; Lim, Haneol; Tahk, Dongha; Sung, Minho; Bae, Won-Gyu; Choi, Se-Jin; Kwak, Moon Kyu; Jeong, Hoon Eui

    2014-08-27

    A simple yet scalable strategy for fabricating dry adhesives with mushroom-shaped micropillars is achieved by a combination of the roll-to-roll process and modulated UV-curable elastic poly(urethane acrylate) (e-PUA) resin. The e-PUA combines the major benefits of commercial PUA and poly(dimethylsiloxane) (PDMS). It not only can be cured within a few seconds like commercial PUA but also possesses good mechanical properties comparable to those of PDMS. A roll-type fabrication system equipped with a rollable mold and a UV exposure unit is also developed for the continuous process. By integrating the roll-to-roll process with the e-PUA, dry adhesives with spatulate tips in the form of a thin flexible film can be generated in a highly continuous and scalable manner. The fabricated dry adhesives with mushroom-shaped microstructures exhibit a strong pull-off strength of up to ∼38.7 N cm(-2) on the glass surface as well as high durability without any noticeable degradation. Furthermore, an automated substrate transportation system equipped with the dry adhesives can transport a 300 mm Si wafer over 10,000 repeating cycles with high accuracy.

  10. Continuous roll-to-roll amorphous silicon photovoltaic manufacturing technology

    NASA Astrophysics Data System (ADS)

    Izu, M.; Ovshinsky, S. R.; Deng, X.; Krisko, A.; Ovshinsky, H. C.; Narasimhan, K. L.; Young, R.

    1994-06-01

    Energy Conversion Devices, Inc. (ECD) has designed and constructed a 2 Megawatt (mW) manufacturing line that produces triple-junction spectrum-splitting a-Si alloy solar cells in a continuous roll-to-roll process. This manufacturing line has reliably and consistently produced high efficiency solar cells. We have demonstrated the production of 4ft 2 triple-junction two band-gap a-Si alloy PV production modules with 8% stable aperture area efficiency. The production line has successfully incorporated: 1) a band-gap profiled a-Si-Ge narrow band-gap solar cell deposited in a continuous roll-to-roll process using a proprietary gas distribution manifold and cathode configuration; and 2) a textured Ag/ZnO back-reflector deposited in a continuous roll-to-roll sputtering machine with production subcell yields greater than 99%.

  11. Ultrashort-pulsed laser processing and solution based coating in roll-to-roll manufacturing of organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Hördemann, C.; Hirschfelder, K.; Schaefer, M.; Gillner, A.

    2015-09-01

    The breakthrough of flexible organic electronics and especially organic photovoltaics is highly dependent on cost-efficient production technologies. Roll-2-Roll processes show potential for a promising solution in terms of high throughput and low-cost production of thin film organic components. Solution based material deposition and integrated laser patterning processes offer new possibilities for versatile production lines. The use of flexible polymeric substrates brings along challenges in laser patterning which have to be overcome. One main challenge when patterning transparent conductive layers on polymeric substrates are material bulges at the edges of the ablated area. Bulges can lead to short circuits in the layer system leading to device failure. Therefore following layers have to have a sufficient thickness to cover and smooth the ridge. In order to minimize the bulging height, a study has been carried out on transparent conductive ITO layers on flexible PET substrates. Ablation results using different beam shapes, such as Gaussian beam, Top-Hat beam and Donut-shaped beam, as well as multi-pass scribing and double-pulsed ablation are compared. Furthermore, lab scale methods for cleaning the patterned layer and eliminating bulges are contrasted to the use of additional water based sacrificial layers in order to obtain an alternative procedure suitable for large scale Roll-2-Roll manufacturing. Besides progress in research, ongoing transfer of laser processes into a Roll-2-Roll demonstrator is illustrated. By using fixed optical elements in combination with a galvanometric scanner, scribing, variable patterning and edge deletion can be performed individually.

  12. High-rate, roll-to-roll nanomanufacturing of flexible systems

    NASA Astrophysics Data System (ADS)

    Cooper, Khershed P.; Wachter, Ralph F.

    2012-10-01

    Since the National Nanotechnology Initiative was first announced in 2000, nanotechnology has developed an impressive catalog of nano-scale structures with building-blocks such as nanoparticles, nanotubes, nanorods, nanopillars, and quantum dots. Similarly, there are accompanying materials processes such as, atomic layer deposition, pulsed layer deposition, nanoprinting, nanoimprinting, transfer printing, nanolithography and nanopatterning. One of the challenges of nanomanufacturing is scaling up these processes reliably and affordably. Roll-to-roll manufacturing is a means for scaling up, for increasing throughput. It is high-speed production using a continuous, moving platform such as a web or a flexible substrate. The adoption of roll-to-roll to nanomanufacturing is novel. The goal is to build structures and devices with nano-scale features and specific functionality. The substrate could be a polymer, metal foil, silk, cloth or paper. The materials to build the structures and multi-level devices could be organic, inorganic or biological. Processing could be solution-based, e.g., ink-jet printing, or vacuum-based, e.g., chemical vapor deposition. Products could be electronics, optoelectronics, membranes, catalysts, microfluidics, lab-on-film, filters, etc. By this means, processing of large and conformal areas is achievable. High-throughput translates into low cost, which is the attraction of roll-to-roll nanomanufacturing. There are technical challenges requiring fundamental scientific advances in materials and process development and in manufacturing and system-integration where achieving nano-scale feature size, resolution and accuracy at high speeds can be major hurdles. We will give an overview of roll-to-roll nanomanufacturing with emphasis on the need to understand the material, process and system complexities, the need for instrumentation, measurement, and process control and describe the concept of cyber-enabled nanomanufacturing for reliable and

  13. Toward large-area roll-to-roll printed nanophotonic sensors

    NASA Astrophysics Data System (ADS)

    Karioja, Pentti; Hiltunen, Jussi; Aikio, Sanna M.; Alajoki, Teemu; Tuominen, Jarkko; Hiltunen, Marianne; Siitonen, Samuli; Kontturi, Ville; Böhlen, Karl; Hauser, Rene; Charlton, Martin; Boersma, Arjen; Lieberzeit, Peter; Felder, Thorsten; Eustace, David; Haskal, Eliav

    2014-05-01

    Polymers have become an important material group in fabricating discrete photonic components and integrated optical devices. This is due to their good properties: high optical transmittance, versatile processability at relative low temperatures and potential for low-cost production. Recently, nanoimprinting or nanoimprint lithography (NIL) has obtained a plenty of research interest. In NIL, a mould is pressed against a substrate coated with a moldable material. After deformation of the material, the mold is separated and a replica of the mold is formed. Compared with conventional lithographic methods, imprinting is simple to carry out, requires less-complicated equipment and can provide high-resolution with high throughput. Nanoimprint lithography has shown potential to become a method for low-cost and high-throughput fabrication of nanostructures. We show the development process of nano-structured, large-area multi-parameter sensors using Photonic Crystal (PC) and Surface Enhanced Raman Scattering (SERS) methodologies for environmental and pharmaceutical applications. We address these challenges by developing roll-to-roll (R2R) UV-nanoimprint fabrication methods. Our development steps are the following: Firstly, the proof of concept structures are fabricated by the use of wafer-level processes in Si-based materials. Secondly, the master molds of successful designs are fabricated, and they are used to transfer the nanophotonic structures into polymer materials using sheet-level UV-nanoimprinting. Thirdly, the sheet-level nanoimprinting processes are transferred to roll-to-roll fabrication. In order to enhance roll-to-roll manufacturing capabilities, silicone-based polymer material development was carried out. In the different development phases, Photonic Crystal and SERS sensor structures with increasing complexities were fabricated using polymer materials in order to enhance sheet-level and roll-to-roll manufacturing processes. In addition, chemical and molecular

  14. Laser direct write system for fabricating seamless roll-to-roll lithography tools

    NASA Astrophysics Data System (ADS)

    Petrzelka, Joseph E.; Hardt, David E.

    2013-03-01

    Implementations of roll to roll contact lithography require new approaches towards manufacturing tooling, including stamps for roll to roll nanoimprint lithography (NIL) and soft lithography. Suitable roll based tools must have seamless micro- or nano-scale patterns and must be scalable to roll widths of one meter. The authors have developed a new centrifugal stamp casting process that can produce uniform cylindrical polymer stamps in a scalable manner. The pattern on the resulting polymer tool is replicated against a corresponding master pattern on the inner diameter of a centrifuge drum. This master pattern is created in photoresist using a UV laser direct write system. This paper discusses the design and implementation of a laser direct write system targeting the internal diameter of a rotating drum. The design uses flying optics to focus a laser beam along the axis of the centrifuge drum and to redirect the beam towards the drum surface. Experimental patterning results show uniform coatings of negative photoresist in the centrifuge drum that are effectively patterned with a 405 nm laser diode. Seamless patterns are shown to be replicated in a 50 mm diameter, 60 mm long cylindrical stamp made from polydimethylsiloxane (PDMS). Direct write results show gratings with line widths of 10 microns in negative photoresist. Using an FPGA, the laser can be accurately timed against the centrifuge encoder to create complex patterns.

  15. Tolerance of Three-Stage CIGS Deposition to Variations Imposed by Roll-to-Roll Processing: Final Technical Report, May 2003 - September 2005

    SciTech Connect

    Beck, M. E.; Britt, J. S.

    2006-01-01

    Three-stage co-evaporation of CIGS imposes stringent limits on the parameter space if high-efficient devices are to result. Substrate temperatures during the 1st stage (as well as during the 2nd and 3rd stage), Se partial pressure, and amount of Na supplied are critical for good nucleation, proper In-Ga-selenide precursor phase, and diffusion of Cu into the precursor, as well as diffusion of Ga through the film. In addition, the degree of Cu-rich excursion impacts maximum performance and process tolerance. Enveloping the above is the basic time-temperature profile inextricably linked to the metals delivery rates. Although high-efficiency, three-stage deposited CIGS devices on the R&D scale are grown at about 20-45 minutes to thicknesses of 2 to 2.5 m, the latter is not a viable approach for an economic manufacturing process. At Global Solar Energy, Inc., CIGS films are typically grown in about 6 minutes to thicknesses of less than 2 m. At the same time, the emissivity and thermal conductivity of stainless steel is vastly different from that of glass, and the reduced growth time poses restrictions on the substrate temperature ramp rates and diffusion of species (reaction kinetics). Material compatibility in the highly corrosive Se environment places limitations on the substrate heaters; i.e., substrate temperatures. Finally, one key advantage of a RTR deposition approach (compact equipment) restricts post CIGS Se exposure and cool-down rates to be vastly different than those practiced in the laboratory.

  16. Roll-to-Roll production of carbon nanotubes based supercapacitors

    NASA Astrophysics Data System (ADS)

    Zhu, Jingyi; Childress, Anthony; Karakaya, Mehmet; Roberts, Mark; Arcilla-Velez, Margarita; Podila, Ramakrishna; Rao, Apparao

    2014-03-01

    Carbon nanomaterials provide an excellent platform for electrochemical double layer capacitors (EDLCs). However, current industrial methods for producing carbon nanotubes are expensive and thereby increase the costs of energy storage to more than 10 Wh/kg. In this regard, we developed a facile roll-to-roll production technology for scalable manufacturing of multi-walled carbon nanotubes (MWNTs) with variable density on run-of-the-mill kitchen Al foils. Our method produces MWNTs with diameter (heights) between 50-100 nm (10-100 μm), and a specific capacitance as high as ~ 100 F/g in non-aqueous electrolytes. In this talk, the fundamental challenges involved in EDLC-suitable MWNT growth, roll-to-roll production, and device manufacturing will be discussed along with electrochemical characteristics of roll-to-roll MWNTs. Research supported by NSF CMMI Grant1246800.

  17. An integrated optical pickup with roll-to-roll fabricated diffractive components.

    PubMed

    Hsu, Jo-Han; Lee, Chi-Hung; Chen, Rongshun

    2011-07-01

    This work designed and fabricated an optical pickup system based on optical films using the roll-to-roll process. The design combined the advantages of the stacked and planar optical pickup system. Two blazed gratings were used as beam splitters for bending the optical path, while a cylindrical lens was used for astigmatic focus-error detection. The proposed design effectively reduces overall system configuration, component cost, and fabrication complexity.

  18. High resolution patterning for flexible electronics via roll-to-roll nanoimprint lithography

    NASA Astrophysics Data System (ADS)

    Sabik, Sami; de Riet, Joris; Yakimets, Iryna; Smits, Edsger

    2014-03-01

    Flexible electronics is a growing field and is currently maturing in applications such as displays, smart packaging, organic light-emitting diodes and organic photovoltaic cells. In order to process on flexible substrates at high throughput and large areas, novel patterning techniques will be essential. Conventional optical lithography is limited in throughput as well as resolution, and requires several alignment steps to generate multi-layered patterns, required for applications such as thin-film transistors. It therefore remains a complex and expensive process. Nanoimprint lithography is an emerging alternative to optical lithography, demonstrating patterning capabilities over a wide range of resolutions, from several microns down to a few nanometres. For display applications, nanoimprint lithography can be used to pattern various layers. Micron sized thin-film transistors for backplane can be fabricated where a self-aligned geometry is used to decrease the number of alignment steps, and increase the overlay accuracy. In addition, nano-structures can be used for optical applications such as anti-reflective surfaces and nano patterned transparent electrodes. Imprint lithography is a fully roll-to-roll compatible process and enables large area and high throughput fabrication for flexible electronics. In this paper we discuss the possibilities and the challenges of large area patterning by roll-to-roll nanoimprint lithography, reviewing micron and nano sized structures realized on our roll-to-roll equipment. Nano patterned transparent electrodes, moth-eye antireflective coatings, and multilevel structures will be covered.

  19. Disposable roll-to-roll hot embossed electrophoresis chip for detection of antibiotic resistance gene mecA in bacteria.

    PubMed

    Liedert, Ralph; Amundsen, Lotta K; Hokkanen, Ari; Mäki, Minna; Aittakorpi, Anne; Pakanen, Mikko; Scherer, James R; Mathies, Richard A; Kurkinen, Marika; Uusitalo, Sanna; Hakalahti, Leena; Nevanen, Tarja K; Siitari, Harri; Söderlund, Hans

    2012-01-21

    We present a high-throughput roll-to-roll (R2R) manufacturing process for foil-based polymethyl methacrylate (PMMA) chips of excellent optical quality. These disposable, R2R hot embossed microfluidic chips are used for the identification of the antibiotic resistance gene mecA in Staphylococcus epidermidis. R2R hot embossing is an emerging manufacturing technology for polymer microfluidic devices. It is based on continuous feeding of a thermoplastic foil through a pressurized area between a heated embossing cylinder and a blank counter cylinder. Although mass fabrication of foil-based microfluidic chips and their use for biological applications were foreseen already some years ago, no such studies have been published previously.

  20. Disposable roll-to-roll hot embossed electrophoresis chip for detection of antibiotic resistance gene mecA in bacteria.

    PubMed

    Liedert, Ralph; Amundsen, Lotta K; Hokkanen, Ari; Mäki, Minna; Aittakorpi, Anne; Pakanen, Mikko; Scherer, James R; Mathies, Richard A; Kurkinen, Marika; Uusitalo, Sanna; Hakalahti, Leena; Nevanen, Tarja K; Siitari, Harri; Söderlund, Hans

    2012-01-21

    We present a high-throughput roll-to-roll (R2R) manufacturing process for foil-based polymethyl methacrylate (PMMA) chips of excellent optical quality. These disposable, R2R hot embossed microfluidic chips are used for the identification of the antibiotic resistance gene mecA in Staphylococcus epidermidis. R2R hot embossing is an emerging manufacturing technology for polymer microfluidic devices. It is based on continuous feeding of a thermoplastic foil through a pressurized area between a heated embossing cylinder and a blank counter cylinder. Although mass fabrication of foil-based microfluidic chips and their use for biological applications were foreseen already some years ago, no such studies have been published previously. PMID:22127494

  1. Roll-to-Roll Nanomanufacturing of Hybrid Nanostructures for Energy Storage Device Design.

    PubMed

    Oakes, Landon; Hanken, Trevor; Carter, Rachel; Yates, William; Pint, Cary L

    2015-07-01

    A key limitation to the practical incorporation of nanostructured materials into emerging applications is the challenge of achieving low-cost, high throughput, and highly replicable scalable nanomanufacturing techniques to produce functional materials. Here, we report a benchtop roll-to-roll technique that builds upon the use of binary solutions of nanomaterials and liquid electrophoretic assembly to rapidly construct hybrid materials for battery design applications. We demonstrate surfactant-free hybrid mixtures of carbon nanotubes, silicon nanoparticles, MoS2 nanosheets, carbon nanohorns, and graphene nanoplatelets. Roll-to-roll electrophoretic assembly from these solutions enables the controlled fabrication of homogeneous coatings of these nanostructures that maintain chemical and physical properties defined by the synergistic combination of nanomaterials utilized without adverse effects of surfactants or impurities that typically limit liquid nanomanufacturing routes. To demonstrate the utility of this nanomanufacturing approach, we employed roll-to-roll electrophoretic processing to fabricate both positive and negative electrodes for lithium ion batteries in less than 30 s. The optimized full-cell battery, containing active materials of prelithiated silicon nanoparticles and MoS2 nanosheets, was assessed to exhibit energy densities of 167 Wh/kgcell(-1) and power densities of 9.6 kW/kgcell(-1). PMID:26053115

  2. Roll-to-Roll Nanomanufacturing of Hybrid Nanostructures for Energy Storage Device Design.

    PubMed

    Oakes, Landon; Hanken, Trevor; Carter, Rachel; Yates, William; Pint, Cary L

    2015-07-01

    A key limitation to the practical incorporation of nanostructured materials into emerging applications is the challenge of achieving low-cost, high throughput, and highly replicable scalable nanomanufacturing techniques to produce functional materials. Here, we report a benchtop roll-to-roll technique that builds upon the use of binary solutions of nanomaterials and liquid electrophoretic assembly to rapidly construct hybrid materials for battery design applications. We demonstrate surfactant-free hybrid mixtures of carbon nanotubes, silicon nanoparticles, MoS2 nanosheets, carbon nanohorns, and graphene nanoplatelets. Roll-to-roll electrophoretic assembly from these solutions enables the controlled fabrication of homogeneous coatings of these nanostructures that maintain chemical and physical properties defined by the synergistic combination of nanomaterials utilized without adverse effects of surfactants or impurities that typically limit liquid nanomanufacturing routes. To demonstrate the utility of this nanomanufacturing approach, we employed roll-to-roll electrophoretic processing to fabricate both positive and negative electrodes for lithium ion batteries in less than 30 s. The optimized full-cell battery, containing active materials of prelithiated silicon nanoparticles and MoS2 nanosheets, was assessed to exhibit energy densities of 167 Wh/kgcell(-1) and power densities of 9.6 kW/kgcell(-1).

  3. Roll to roll fabrication technologies for optoelectronic and electronic devices and sensors

    NASA Astrophysics Data System (ADS)

    Maaninen, A.; Tuomikoski, M.; Kivimäki, L.; Kololuoma, T.; Välimäki, M.; Leinonen, M.; Känsäkoski, M.

    2005-09-01

    Embedding of optoelectrical, optical, and electrical functionalities into low-cost products like product packages and printed matter can be used to increase their information content. For these purposes, components like displays, photodetectors, light sources, solar cells, battery elements, diffractive optical elements, lightguides, electrical conductors, resistors, transistors, switching elements etc. and their integration to functional modules are required. Also the need of rapid and reliable di-agnostic systems for wellness and healthcare applications is apparent. Today the time from sampling to result can take hours or even several days. In future the target is to analyze the sample within a few minutes for further action. Additionally, the price of the components for low-end products and disposable sensors has to be in cent scale or preferably below that. Therefore, new, cost-effective, and volume scale capable manufacturing techniques are required. Recent developments of liquid-phase processable electrical and optical polymeric, inorganic, and hybrid material inks together with biocompatible materials have made it possible to fabricate functional components by conventional roll-to-roll techniques such as gravure printing on flexible paper and plastic like substrates. In this paper, we show our current achievements in the field of roll-to-roll fabricated electronics, optoelec-tronics and biosensors. With examples of light guiding structures, organic light emitting diodes, biocompatible materials etc., we demonstrate the huge potential of roll to roll fabrication as a low cost mass production technology for future low end electronic products.

  4. Planarization coating for polyimide substrates used in roll-to-roll fabrication of active matrix backplanes for flexible displays

    NASA Astrophysics Data System (ADS)

    Almanza-Workman, A. Marcia; Jeans, Albert; Braymen, Steve; Elder, Richard E.; Garcia, Robert A.; de la Fuente Vornbrock, Alejandro; Hauschildt, Jason; Holland, Edward; Jackson, Warren; Jam, Mehrban; Jeffrey, Frank; Junge, Kelly; Kim, Han-Jun; Kwon, Ohseung; Larson, Don; Luo, Hao; Maltabes, John; Mei, Ping; Perlov, Craig; Smith, Mark; Stieler, Dan; Taussig, Carl P.; Trovinger, Steve; Zhao, Lihua

    2012-03-01

    Good surface quality of plastic substrates is essential to reduce pixel defects during roll-to-roll fabrication of flexible display active matrix backplanes. Standard polyimide substrates have a high density of "bumps" from fillers and belt marks and other defects from dust and surface scratching. Some of these defects could be the source of shunts in dielectrics. The gate dielectric must prevent shorts between the source/drain and the gate in the transistors, resist shorts in the hold capacitor and stop shorts in the data/gate line crossovers in active matrix backplanes fabricated by self-aligned imprint lithography (SAIL) roll-to-roll processes. Otherwise data and gate lines will become shorted creating line or pixel defects. In this paper, we discuss the development of a proprietary UV curable planarization material that can be coated by roll-to-roll processes. This material was engineered to have low shrinkage, excellent adhesion to polyimide, high dry etch resistance, and great chemical and thermal stability. Results from PECVD deposition of an amorphous silicon stack on the planarized polyimide and compatibility with roll-to-roll processes to fabricate active matrix backplanes are also discussed. The effect of the planarization on defects in the stack, shunts in the dielectric and curvature of finished arrays will also be described.

  5. Diamond turning of high-precision roll-to-roll imprinting molds for fabricating subwavelength gratings

    NASA Astrophysics Data System (ADS)

    Liu, Chun-Wei; Yan, Jiwang; Lin, Shih-Chieh

    2016-06-01

    Diamond turning of high-precision molds is a vital process for the roll-to-roll-based ultraviolet resin imprinting process in fabricating subwavelength gratings. The effects of the grating shape and grating period on diffraction efficiencies and diffraction angles were simulated. Experiments were then conducted to examine the effects of shape design, grating period, and cutting speed on machinability of the mold. According to the optical measurement results, the performance of the subwavelength gratings matched the design well at various incident angles. The results confirm that diamond turning of high-precision molds is a feasible approach for ensuring the continual mass production of subwavelength gratings.

  6. Hot embossing holographic images in BOPP shrink films through large-area roll-to-roll nanoimprint lithography

    NASA Astrophysics Data System (ADS)

    Jiang, Menglin; Lin, Shiwei; Jiang, Wenkai; Pan, Nengqian

    2014-08-01

    Diffraction grating-based holographic images have been successfully replicated in biaxially oriented polypropylene (BOPP) shrink films through large-area roll-to-roll nanoimprint technique. Such hot embossing of holographic images on BOPP films represents a promising means of creating novel security features in packaging applications. The major limitation of the high-quality replication is the relatively large thermal shrinkage of BOPP shrink film. However, although an appropriate shrinkage is demanded after embossing, over-shrinking not only causes distortion in embossed images, but also reduces the various properties of BOPP shrink films mainly due to the disappearance of orientation. The effects of embossing temperature on the mechanical, thermal and optical properties as well as polymer surface morphologies were systematically analyzed. The results show that the optimal process parameters are listed as follows: the embossing temperature at 104-110 °C, embossing force 6 kg/cm2 and film speed 32 m/min. The variation in flow behavior of polymer surface during hot embossing process is highly dependent on the temperature. In addition, the adhesion from the direct contact between the rubber press roller and polymer surfaces is suggested to cause the serious optical properties failure.

  7. Continuous roll-to-roll serpentine deposition for high throughput a-Si PV manufacturing

    SciTech Connect

    Izu, M.; Ovshinsky, H.C.; Deng, X.; Krisko, A.J.; Narasimhan, K.L.; Crucet, R.; Laarman, T.; Myatt, A.; Ovshinsky, S.R.

    1994-12-31

    In order to further improve the economies of scale which are inherent in ECD`s continuous roll-to-roll amorphous silicon alloy solar cell manufacturing process, the authors have developed a concept for a serpentine web plasma CVD deposition process to maximize throughput while keeping the size of the deposition chambers small. When this technique is incorporated into a continuous roll-to-roll PV manufacturing process, it will maximize the throughput for a high volume production plant, reduce the machine cost, improve gas utilization, reduce power consumption, and improve the solar cell stability. To demonstrate the serpentine web deposition concept, the authors have constructed a single loop serpentine deposition chamber to deposit a-Si for n-i-p structure solar cells. During the initial process of optimization, they have produced single-junction a-Si solar cells with 8.6% efficiency, and triple-junction a-Si solar cells with a 9.5% initial efficiency, where the top cell intrinsic layer was deposited in the serpentine deposition chamber.

  8. High-speed roll-to-roll manufacturing of graphene using a concentric tube CVD reactor

    PubMed Central

    Polsen, Erik S.; McNerny, Daniel Q.; Viswanath, B.; Pattinson, Sebastian W.; John Hart, A.

    2015-01-01

    We present the design of a concentric tube (CT) reactor for roll-to-roll chemical vapor deposition (CVD) on flexible substrates, and its application to continuous production of graphene on copper foil. In the CTCVD reactor, the thin foil substrate is helically wrapped around the inner tube, and translates through the gap between the concentric tubes. We use a bench-scale prototype machine to synthesize graphene on copper substrates at translation speeds varying from 25 mm/min to 500 mm/min, and investigate the influence of process parameters on the uniformity and coverage of graphene on a continuously moving foil. At lower speeds, high-quality monolayer graphene is formed; at higher speeds, rapid nucleation of small graphene domains is observed, yet coalescence is prevented by the limited residence time in the CTCVD system. We show that a smooth isothermal transition between the reducing and carbon-containing atmospheres, enabled by injection of the carbon feedstock via radial holes in the inner tube, is essential to high-quality roll-to-roll graphene CVD. We discuss how the foil quality and microstructure limit the uniformity of graphene over macroscopic dimensions. We conclude by discussing means of scaling and reconfiguring the CTCVD design based on general requirements for 2-D materials manufacturing. PMID:25997124

  9. Multilength Scale Patterning of Functional Layers by Roll-to-Roll Ultraviolet-Light-Assisted Nanoimprint Lithography.

    PubMed

    Leitgeb, Markus; Nees, Dieter; Ruttloff, Stephan; Palfinger, Ursula; Götz, Johannes; Liska, Robert; Belegratis, Maria R; Stadlober, Barbara

    2016-05-24

    Top-down fabrication of nanostructures with high throughput is still a challenge. We demonstrate the fast (>10 m/min) and continuous fabrication of multilength scale structures by roll-to-roll UV-nanoimprint lithography on a 250 mm wide web. The large-area nanopatterning is enabled by a multicomponent UV-curable resist system (JRcure) with viscous, mechanical, and surface properties that are tunable over a wide range to either allow for usage as polymer stamp material or as imprint resist. The adjustable elasticity and surface chemistry of the resist system enable multistep self-replication of structured resist layers. Decisive for defect-free UV-nanoimprinting in roll-to-roll is the minimization of the surface energies of stamp and resist, and the stepwise reduction of the stiffness from one layer to the next is essential for optimizing the reproduction fidelity especially for nanoscale features. Accordingly, we demonstrate the continuous replication of 3D nanostructures and the high-throughput fabrication of multilength scale resist structures resulting in flexible polyethylenetherephtalate film rolls with superhydrophobic properties. Moreover, a water-soluble UV-imprint resist (JRlift) is introduced that enables residue-free nanoimprinting in roll-to-roll. Thereby we could demonstrate high-throughput fabrication of metallic patterns with only 200 nm line width.

  10. Multilength Scale Patterning of Functional Layers by Roll-to-Roll Ultraviolet-Light-Assisted Nanoimprint Lithography.

    PubMed

    Leitgeb, Markus; Nees, Dieter; Ruttloff, Stephan; Palfinger, Ursula; Götz, Johannes; Liska, Robert; Belegratis, Maria R; Stadlober, Barbara

    2016-05-24

    Top-down fabrication of nanostructures with high throughput is still a challenge. We demonstrate the fast (>10 m/min) and continuous fabrication of multilength scale structures by roll-to-roll UV-nanoimprint lithography on a 250 mm wide web. The large-area nanopatterning is enabled by a multicomponent UV-curable resist system (JRcure) with viscous, mechanical, and surface properties that are tunable over a wide range to either allow for usage as polymer stamp material or as imprint resist. The adjustable elasticity and surface chemistry of the resist system enable multistep self-replication of structured resist layers. Decisive for defect-free UV-nanoimprinting in roll-to-roll is the minimization of the surface energies of stamp and resist, and the stepwise reduction of the stiffness from one layer to the next is essential for optimizing the reproduction fidelity especially for nanoscale features. Accordingly, we demonstrate the continuous replication of 3D nanostructures and the high-throughput fabrication of multilength scale resist structures resulting in flexible polyethylenetherephtalate film rolls with superhydrophobic properties. Moreover, a water-soluble UV-imprint resist (JRlift) is introduced that enables residue-free nanoimprinting in roll-to-roll. Thereby we could demonstrate high-throughput fabrication of metallic patterns with only 200 nm line width. PMID:27023664

  11. Comparison of roll-to-roll replication approaches for microfluidic and optical functions in lab-on-a-chip diagnostic devices

    NASA Astrophysics Data System (ADS)

    Brecher, Christian; Baum, Christoph; Bastuck, Thomas

    2015-03-01

    Economically advantageous microfabrication technologies for lab-on-a-chip diagnostic devices substituting commonly used glass etching or injection molding processes are one of the key enablers for the emerging market of microfluidic devices. On-site detection in fields of life sciences, point of care diagnostics and environmental analysis requires compact, disposable and highly functionalized systems. Roll-to-roll production as a high volume process has become the emerging fabrication technology for integrated, complex high technology products within recent years (e.g. fuel cells). Differently functionalized polymer films enable researchers to create a new generation of lab-on-a-chip devices by combining electronic, microfluidic and optical functions in multilayer architecture. For replication of microfluidic and optical functions via roll-to-roll production process competitive approaches are available. One of them is to imprint fluidic channels and optical structures of micro- or nanometer scale from embossing rollers into ultraviolet (UV) curable lacquers on polymer substrates. Depending on dimension, shape and quantity of those structures there are alternative manufacturing technologies for the embossing roller. Ultra-precise diamond turning, electroforming or casting polymer materials are used either for direct structuring or manufacturing of roller sleeves. Mastering methods are selected for application considering replication quality required and structure complexity. Criteria for the replication quality are surface roughness and contour accuracy. Structure complexity is evaluated by shapes producible (e.g. linear, circular) and aspect ratio. Costs for the mastering process and structure lifetime are major cost factors. The alternative replication approaches are introduced and analyzed corresponding to the criteria presented. Advantages and drawbacks of each technology are discussed and exemplary applications are presented.

  12. Noncontact conductivity and dielectric measurement for high throughput roll-to-roll nanomanufacturing

    PubMed Central

    Orloff, Nathan D.; Long, Christian J.; Obrzut, Jan; Maillaud, Laurent; Mirri, Francesca; Kole, Thomas P.; McMichael, Robert D.; Pasquali, Matteo; Stranick, Stephan J.; Alexander Liddle, J.

    2015-01-01

    Advances in roll-to-roll processing of graphene and carbon nanotubes have at last led to the continuous production of high-quality coatings and filaments, ushering in a wave of applications for flexible and wearable electronics, woven fabrics, and wires. These applications often require specific electrical properties, and hence precise control over material micro- and nanostructure. While such control can be achieved, in principle, by closed-loop processing methods, there are relatively few noncontact and nondestructive options for quantifying the electrical properties of materials on a moving web at the speed required in modern nanomanufacturing. Here, we demonstrate a noncontact microwave method for measuring the dielectric constant and conductivity (or geometry for samples of known dielectric properties) of materials in a millisecond. Such measurement times are compatible with current and future industrial needs, enabling real-time materials characterization and in-line control of processing variables without disrupting production. PMID:26592441

  13. Noncontact conductivity and dielectric measurement for high throughput roll-to-roll nanomanufacturing.

    PubMed

    Orloff, Nathan D; Long, Christian J; Obrzut, Jan; Maillaud, Laurent; Mirri, Francesca; Kole, Thomas P; McMichael, Robert D; Pasquali, Matteo; Stranick, Stephan J; Liddle, J Alexander

    2015-01-01

    Advances in roll-to-roll processing of graphene and carbon nanotubes have at last led to the continuous production of high-quality coatings and filaments, ushering in a wave of applications for flexible and wearable electronics, woven fabrics, and wires. These applications often require specific electrical properties, and hence precise control over material micro- and nanostructure. While such control can be achieved, in principle, by closed-loop processing methods, there are relatively few noncontact and nondestructive options for quantifying the electrical properties of materials on a moving web at the speed required in modern nanomanufacturing. Here, we demonstrate a noncontact microwave method for measuring the dielectric constant and conductivity (or geometry for samples of known dielectric properties) of materials in a millisecond. Such measurement times are compatible with current and future industrial needs, enabling real-time materials characterization and in-line control of processing variables without disrupting production. PMID:26592441

  14. Noncontact conductivity and dielectric measurement for high throughput roll-to-roll nanomanufacturing

    NASA Astrophysics Data System (ADS)

    Orloff, Nathan D.; Long, Christian J.; Obrzut, Jan; Maillaud, Laurent; Mirri, Francesca; Kole, Thomas P.; McMichael, Robert D.; Pasquali, Matteo; Stranick, Stephan J.; Alexander Liddle, J.

    2015-11-01

    Advances in roll-to-roll processing of graphene and carbon nanotubes have at last led to the continuous production of high-quality coatings and filaments, ushering in a wave of applications for flexible and wearable electronics, woven fabrics, and wires. These applications often require specific electrical properties, and hence precise control over material micro- and nanostructure. While such control can be achieved, in principle, by closed-loop processing methods, there are relatively few noncontact and nondestructive options for quantifying the electrical properties of materials on a moving web at the speed required in modern nanomanufacturing. Here, we demonstrate a noncontact microwave method for measuring the dielectric constant and conductivity (or geometry for samples of known dielectric properties) of materials in a millisecond. Such measurement times are compatible with current and future industrial needs, enabling real-time materials characterization and in-line control of processing variables without disrupting production.

  15. Eco green flexible hybrid photovoltaic-thermoelectric solar cells with nanoimprint technology and roll-to-roll manufacturing

    NASA Astrophysics Data System (ADS)

    Varadan, Vijay K.; Choi, Sang H.

    2010-04-01

    This paper explores the technical and commercial feasibility of nanotechnology based, high-efficiency, photovoltaic-thermoelectric hybrid solar cells as an environmentally-friendly, renewable energy source for residential and commercial buildings. To convert as much as possible of the usable photovoltaic (58% of the Energy Density) and thermoelectric (42% of the Energy Density) solar spectrum into electricity, a hybrid multilayer system is presented which comprises of 1) carbon nanotube (CNT) embedded in conducting polymers such as P3HT (poly(3-hexylthiophene) or P3OT (poly3-octylthiophene), 2) 3D gold nanostructures exhibiting plasmonic resonances for energy conversion, 3) nanoantenna architecture to capture IR energy, 4) a composite of Bi2Te3, SiGe nanocrystals and Au nanoshells as thermoelectric energy conversion layer, 5) configuration of the above items engineered in the form of meta-material designs that by virtue of their 3D structures ensure that incident light is neither reflected nor transmitted, but is rather all absorbed, 6) a multilayer arrangement of the above layers in a fractal architecture to capture all the wavelengths from 200 to 3000 nm8 and the matching electronic interface for each layer. The roll-to-roll manufacturing method presented will enable economical large-scale production of solar panels. This potentially transformational technology has the ability to replace the Si solar cell technology by reducing costs from 0.18/KWh to 0.003/KWh while introducing a more environmentally-friendly manufacturing process.

  16. Roll-to-Roll Production of Spray Coated N-doped Carbon Nanotube Electrodes for Supercapacitors

    NASA Astrophysics Data System (ADS)

    Karakaya, Mehmet; Zhu, Jingyi; Raghavendra, Achyut; Podila, Ramakrishna; Parler, Samuel; Kaplan, James; Rao, Apparao; Cornell Dubilier Electronics, Inc. Collaboration

    2015-03-01

    Although nanocarbons are being increasingly used in energy storage, there has been a lack of inexpensive, continuous and scalable synthesis methods. Here we present a scalable roll-to-roll spray coating process for synthesizing supercapacitors from randomly oriented multi-walled carbon nanotubes electrodes on Al foils, which yield high power and energy densities (~ 700 mW/cm3 and 1 mWh/cm3) and cycle stability (>10000 cycles) on par with Li-ion thin film batteries. Our cost analysis shows that the R2R spray coating process can produce supercapacitors with 10 times the energy density of conventional activated carbon devices at ~ 17% lower cost. NSF CMMI SNM Award #1246800.

  17. Roll-to-roll production of spray coated N-doped carbon nanotube electrodes for supercapacitors

    NASA Astrophysics Data System (ADS)

    Karakaya, Mehmet; Zhu, Jingyi; Raghavendra, Achyut J.; Podila, Ramakrishna; Parler, Samuel G.; Kaplan, James P.; Rao, Apparao M.

    2014-12-01

    Although carbon nanomaterials are being increasingly used in energy storage, there has been a lack of inexpensive, continuous, and scalable synthesis methods. Here, we present a scalable roll-to-roll (R2R) spray coating process for synthesizing randomly oriented multi-walled carbon nanotubes electrodes on Al foils. The coin and jellyroll type supercapacitors comprised such electrodes yield high power densities (˜700 mW/cm3) and energy densities (1 mW h/cm3) on par with Li-ion thin film batteries. These devices exhibit excellent cycle stability with no loss in performance over more than a thousand cycles. Our cost analysis shows that the R2R spray coating process can produce supercapacitors with 10 times the energy density of conventional activated carbon devices at ˜17% lower cost.

  18. Integrated optical interconnection for polymeric planar lightwave circuit device using roll-to-roll ultraviolet imprint

    NASA Astrophysics Data System (ADS)

    Cho, Sang Uk; Kang, Ho Ju; Chang, Sunghwan; Choi, Doo-sun; Kim, Chang-Seok; Jeong, Myung Yung

    2014-08-01

    We propose an integrated structure that combines chip and fiber array blocks for optical interconnection with a polymeric planar lightwave circuit (PLC) device using the roll-to-roll imprint process. The fiber array blocks and PLC chip of the integrated structure are fabricated on the same substrate, and the alignments in the three spatial directions were established with the insertion of an optical fiber. The characteristics of the integrated structure were evaluated by fabricating a 1×2 optical splitter device. The structure had an insertion loss of 3.9 dB, and the optical uniformity of the channel was 0.1 dB, indicating that the same performance for an active alignment can be expected.

  19. Compact Roll-to-Roll Coater for in Situ X-ray Diffraction Characterization of Organic Electronics Printing.

    PubMed

    Gu, Xiaodan; Reinspach, Julia; Worfolk, Brian J; Diao, Ying; Zhou, Yan; Yan, Hongping; Gu, Kevin; Mannsfeld, Stefan; Toney, Michael F; Bao, Zhenan

    2016-01-27

    We describe a compact roll-to-roll (R2R) coater that is capable of tracking the crystallization process of semiconducting polymers during solution printing using X-ray scattering at synchrotron beamlines. An improved understanding of the morphology evolution during the solution-processing of organic semiconductor materials during R2R coating processes is necessary to bridge the gap between "lab" and "fab". The instrument consists of a vacuum chuck to hold the flexible plastic substrate uniformly flat for grazing incidence X-ray scattering. The time resolution of the drying process that is achievable can be tuned by controlling two independent motor speeds, namely, the speed of the moving flexible substrate and the speed of the printer head moving in the opposite direction. With this novel design, we are able to achieve a wide range of drying time resolutions, from tens of milliseconds to seconds. This allows examination of the crystallization process over either fast or slow drying processes depending on coating conditions. Using regioregular poly(3-hexylthiophene-2,5-diyl) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) inks based on two different solvents as a model system, we demonstrate the capability of our in situ R2R printing tool by observing two distinct crystallization processes for inks drying from the solvents with different boiling points (evaporation rates). We also observed delayed on-set point for the crystallization of P3HT polymer in the 1:1 P3HT/PCBM BHJ blend, and the inhibited crystallization of the P3HT during the late stage of the drying process. PMID:26714412

  20. Compact Roll-to-Roll Coater for in Situ X-ray Diffraction Characterization of Organic Electronics Printing.

    PubMed

    Gu, Xiaodan; Reinspach, Julia; Worfolk, Brian J; Diao, Ying; Zhou, Yan; Yan, Hongping; Gu, Kevin; Mannsfeld, Stefan; Toney, Michael F; Bao, Zhenan

    2016-01-27

    We describe a compact roll-to-roll (R2R) coater that is capable of tracking the crystallization process of semiconducting polymers during solution printing using X-ray scattering at synchrotron beamlines. An improved understanding of the morphology evolution during the solution-processing of organic semiconductor materials during R2R coating processes is necessary to bridge the gap between "lab" and "fab". The instrument consists of a vacuum chuck to hold the flexible plastic substrate uniformly flat for grazing incidence X-ray scattering. The time resolution of the drying process that is achievable can be tuned by controlling two independent motor speeds, namely, the speed of the moving flexible substrate and the speed of the printer head moving in the opposite direction. With this novel design, we are able to achieve a wide range of drying time resolutions, from tens of milliseconds to seconds. This allows examination of the crystallization process over either fast or slow drying processes depending on coating conditions. Using regioregular poly(3-hexylthiophene-2,5-diyl) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) inks based on two different solvents as a model system, we demonstrate the capability of our in situ R2R printing tool by observing two distinct crystallization processes for inks drying from the solvents with different boiling points (evaporation rates). We also observed delayed on-set point for the crystallization of P3HT polymer in the 1:1 P3HT/PCBM BHJ blend, and the inhibited crystallization of the P3HT during the late stage of the drying process.

  1. Large format cylindrical lens films formed by roll-to-roll ultraviolet embossing and applications as diffusion films

    NASA Astrophysics Data System (ADS)

    Shan, X. C.; Liu, T.; Mohaime, M.; Salam, B.; Liu, Y. C.

    2015-03-01

    A roll-to-roll (R2R) ultraviolet (UV) embossing system has been developed for manufacturing micro features on continuous flexible films. The R2R UV embossing system, which has an embossing roller of 160 mm in diameter, can handle flexible polymer films with a width up to 500 mm and thickness ranging from 0.05 to 0.5 mm. A metal sheet template with micro features on its surface is mounted to the embossing roller and used as embossing mould. A slot die coating unit that has a coating width of 250 mm is used to deposit liquid UV curable resin on polymer films and coating thickness ranging from 10 to 50 µm has been achieved. Continuous roll-to-roll UV embossing is conducted and optical films with cylindrical lens arrays (curvature radius = 112  ±  2 µm, sag height = 28  ±  0.5 µm and pitch = 150  ±  2 µm) are formed. The optical films are used for diffusion to improve light uniformity of a printed lighting film that consists of lighting stripes and dark blank lines. The evaluation results show that the non-uniformity of light intensity can be reduced from 30% (with only lighting panel) to about 3% with the cylindrical lens films.

  2. Patterned immobilization of antibodies within roll-to-roll hot embossed polymeric microfluidic channels.

    PubMed

    Feyssa, Belachew; Liedert, Christina; Kivimaki, Liisa; Johansson, Leena-Sisko; Jantunen, Heli; Hakalahti, Leena

    2013-01-01

    This paper describes a method for the patterned immobilization of capture antibodies into a microfluidic platform fabricated by roll-to-roll (R2R) hot embossing on poly (methyl methacrylate) (PMMA). Covalent attachment of antibodies was achieved by two sequential inkjet printing steps. First, a polyethyleneimine (PEI) layer was deposited onto oxygen plasma activated PMMA foil and further cross-linked with glutaraldehyde (GA) to provide an amine-reactive aldehyde surface (PEI-GA). This step was followed by a second deposition of antibody by overprinting on the PEI-GA patterned PMMA foil. The PEI polymer ink was first formulated to ensure stable drop formation in inkjet printing and the printed films were characterized using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). Anti-CRP antibody was patterned on PMMA foil by the developed method and bonded permanently with R2R hot embossed PMMA microchannels by solvent bonding lamination. The functionality of the immobilized antibody inside the microfluidic channel was evaluated by fluorescence-based sandwich immunoassay for detection of C-reactive protein (CRP). The antibody-antigen assay exhibited a good level of linearity over the range of 10 ng/ml to 500 ng/ml (R(2) = 0.991) with a calculated detection limit of 5.2 ng/ml. The developed patterning method is straightforward, rapid and provides a versatile approach for creating multiple protein patterns in a single microfluidic channel for multiplexed immunoassays.

  3. Patterned Immobilization of Antibodies within Roll-to-Roll Hot Embossed Polymeric Microfluidic Channels

    PubMed Central

    Feyssa, Belachew; Liedert, Christina; Kivimaki, Liisa; Johansson, Leena-Sisko; Jantunen, Heli; Hakalahti, Leena

    2013-01-01

    This paper describes a method for the patterned immobilization of capture antibodies into a microfluidic platform fabricated by roll-to-roll (R2R) hot embossing on poly (methyl methacrylate) (PMMA). Covalent attachment of antibodies was achieved by two sequential inkjet printing steps. First, a polyethyleneimine (PEI) layer was deposited onto oxygen plasma activated PMMA foil and further cross-linked with glutaraldehyde (GA) to provide an amine-reactive aldehyde surface (PEI-GA). This step was followed by a second deposition of antibody by overprinting on the PEI-GA patterned PMMA foil. The PEI polymer ink was first formulated to ensure stable drop formation in inkjet printing and the printed films were characterized using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). Anti-CRP antibody was patterned on PMMA foil by the developed method and bonded permanently with R2R hot embossed PMMA microchannels by solvent bonding lamination. The functionality of the immobilized antibody inside the microfluidic channel was evaluated by fluorescence-based sandwich immunoassay for detection of C-reactive protein (CRP). The antibody-antigen assay exhibited a good level of linearity over the range of 10 ng/ml to 500 ng/ml (R2 = 0.991) with a calculated detection limit of 5.2 ng/ml. The developed patterning method is straightforward, rapid and provides a versatile approach for creating multiple protein patterns in a single microfluidic channel for multiplexed immunoassays. PMID:23874811

  4. Patterned immobilization of antibodies within roll-to-roll hot embossed polymeric microfluidic channels.

    PubMed

    Feyssa, Belachew; Liedert, Christina; Kivimaki, Liisa; Johansson, Leena-Sisko; Jantunen, Heli; Hakalahti, Leena

    2013-01-01

    This paper describes a method for the patterned immobilization of capture antibodies into a microfluidic platform fabricated by roll-to-roll (R2R) hot embossing on poly (methyl methacrylate) (PMMA). Covalent attachment of antibodies was achieved by two sequential inkjet printing steps. First, a polyethyleneimine (PEI) layer was deposited onto oxygen plasma activated PMMA foil and further cross-linked with glutaraldehyde (GA) to provide an amine-reactive aldehyde surface (PEI-GA). This step was followed by a second deposition of antibody by overprinting on the PEI-GA patterned PMMA foil. The PEI polymer ink was first formulated to ensure stable drop formation in inkjet printing and the printed films were characterized using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). Anti-CRP antibody was patterned on PMMA foil by the developed method and bonded permanently with R2R hot embossed PMMA microchannels by solvent bonding lamination. The functionality of the immobilized antibody inside the microfluidic channel was evaluated by fluorescence-based sandwich immunoassay for detection of C-reactive protein (CRP). The antibody-antigen assay exhibited a good level of linearity over the range of 10 ng/ml to 500 ng/ml (R(2) = 0.991) with a calculated detection limit of 5.2 ng/ml. The developed patterning method is straightforward, rapid and provides a versatile approach for creating multiple protein patterns in a single microfluidic channel for multiplexed immunoassays. PMID:23874811

  5. Roll-to-Roll Screen Printed Radio Frequency Identification Transponder Antennas for Vehicle Tracking Systems

    NASA Astrophysics Data System (ADS)

    Zichner, Ralf; Baumann, Reinhard R.

    2013-05-01

    Vehicle tracking systems based on ultra high frequency (UHF) radio frequency identification (RFID) technology are already introduced to control the access to car parks and corporate premises. For this field of application so-called Windshield RFID transponder labels are used, which are applied to the inside of the windshield. State of the art for manufacturing these transponder antennas is the traditional lithography/etching approach. Furthermore the performance of these transponders is limited to a reading distance of approximately 5 m which results in car speed limit of 5 km/h for identification. However, to achieve improved performance compared to existing all-purpose transponders and a dramatic cost reduction, an optimized antenna design is needed which takes into account the special dielectric and in particular metallic car environment of the tag and an roll-to-roll (R2R) printing manufacturing process. In this paper we focus on the development of a customized UHF RFID transponder antenna design, which is adopted for vehicle geometry as well as R2R screen printing manufacturing processes.

  6. Roll-to-roll embedded conductive structures integrated into organic photovoltaic devices

    NASA Astrophysics Data System (ADS)

    van de Wiel, H. J.; Galagan, Y.; van Lammeren, T. J.; de Riet, J. F. J.; Gilot, J.; Nagelkerke, M. G. M.; Lelieveld, R. H. C. A. T.; Shanmugam, S.; Pagudala, A.; Hui, D.; Groen, W. A.

    2013-12-01

    Highly conductive screen printed metallic (silver) structures (current collecting grids) combined with poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) are a viable replacement for indium tin oxide (ITO) and inkjet printed silver as transparent electrode materials. To provide successful integration into organic photovoltaic (OPV) devices, screen printed silver current collecting grids should be embedded into a substrate to avoid topology issues. In this study micron-thick conductive structures are embedded and integrated into OPV devices. The embedded structures are produced roll-to-roll with optimized process settings and materials. Topology measurements show that the embedded grids are well suited for integration into OPV devices since the surface is almost without spikes and has low surface roughness. JV measurements of OPV devices with embedded structures on a polyethylene terephthalate/silicon nitride (PET/SiN) substrate show an efficiency of 2.15%, which is significantly higher than identical flexible devices with ITO (1.02%) and inkjet printed silver (1.48%). The use of embedded screen printed silver instead of ITO and inkjet printed silver in OPV devices will allow for higher efficiency devices which can be produced with larger design and process freedom.

  7. In-line roll-to-roll metrology for flexible electronics

    NASA Astrophysics Data System (ADS)

    Kimbrough, Brad

    2015-09-01

    The flexible electronics market continues to grow at a rapid pace. Increasing numbers of applications employ the flexible components including displays, biomedical devices, smart apparel, and advanced sensors. To maintain performance and lifetime, many characteristics of the substrate and deposited layers must be monitored. This includes defects, surface roughness, and feature alignment. Ideally, in-situ metrology can be employed in roll-to-roll (R2R) equipment to allow for real-time process control. This presents the necessary three-dimensional metrology system with several challenging requirements: high vertical and transverse resolution, large field-of-view, extremely fast measurement times, and robust vibration immunity. This paper will discuss the design and performance of a compact, low-cost, large-field interferometric probe for in-situ measurement of R2R substrates. Samples with a variety of known and unknown features and roughnesses will be measured to characterize the performance of the system. Static and moving substrates will be measured to examine effects on results. Optimization of processing to allow for on-board analysis will be examined. Lastly, the paper will discuss how such probes may be arrayed to provide a high degree of areal coverage of the flexible substrate under test.

  8. Multivariable passive RFID vapor sensors: roll-to-roll fabrication on a flexible substrate.

    PubMed

    Potyrailo, Radislav A; Burns, Andrew; Surman, Cheryl; Lee, D J; McGinniss, Edward

    2012-06-21

    We demonstrate roll-to-roll (R2R) fabrication of highly selective, battery-free radio frequency identification (RFID) sensors on a flexible polyethylene terephthalate (PET) polymeric substrate. Selectivity of our developed RFID sensors is provided by measurements of their resonance impedance spectra, followed by the multivariate analysis of spectral features, and correlation of these spectral features to the concentrations of vapors of interest. The multivariate analysis of spectral features also provides the ability for the rejection of ambient interferences. As a demonstration of our R2R fabrication process, we employed polyetherurethane (PEUT) as a "classic" sensing material, extruded this sensing material as 25, 75, and 125-μm thick films, and thermally laminated the films onto RFID inlays, rapidly producing approximately 5000 vapor sensors. We further tested these RFID vapor sensors for their response selectivity toward several model vapors such as toluene, acetone, and ethanol as well as water vapor as an abundant interferent. Our RFID sensing concept features 16-bit resolution provided by the sensor reader, granting a highly desired independence from costly proprietary RFID memory chips with a low-resolution analog input. Future steps are being planned for field-testing of these sensors in numerous conditions.

  9. Large Scale Triboelectric Nanogenerator and Self-Powered Pressure Sensor Array Using Low Cost Roll-to-Roll UV Embossing

    NASA Astrophysics Data System (ADS)

    Dhakar, Lokesh; Gudla, Sudeep; Shan, Xuechuan; Wang, Zhiping; Tay, Francis Eng Hock; Heng, Chun-Huat; Lee, Chengkuo

    2016-02-01

    Triboelectric nanogenerators (TENGs) have emerged as a potential solution for mechanical energy harvesting over conventional mechanisms such as piezoelectric and electromagnetic, due to easy fabrication, high efficiency and wider choice of materials. Traditional fabrication techniques used to realize TENGs involve plasma etching, soft lithography and nanoparticle deposition for higher performance. But lack of truly scalable fabrication processes still remains a critical challenge and bottleneck in the path of bringing TENGs to commercial production. In this paper, we demonstrate fabrication of large scale triboelectric nanogenerator (LS-TENG) using roll-to-roll ultraviolet embossing to pattern polyethylene terephthalate sheets. These LS-TENGs can be used to harvest energy from human motion and vehicle motion from embedded devices in floors and roads, respectively. LS-TENG generated a power density of 62.5 mW m-2. Using roll-to-roll processing technique, we also demonstrate a large scale triboelectric pressure sensor array with pressure detection sensitivity of 1.33 V kPa-1. The large scale pressure sensor array has applications in self-powered motion tracking, posture monitoring and electronic skin applications. This work demonstrates scalable fabrication of TENGs and self-powered pressure sensor arrays, which will lead to extremely low cost and bring them closer to commercial production.

  10. Large Scale Triboelectric Nanogenerator and Self-Powered Pressure Sensor Array Using Low Cost Roll-to-Roll UV Embossing

    PubMed Central

    Dhakar, Lokesh; Gudla, Sudeep; Shan, Xuechuan; Wang, Zhiping; Tay, Francis Eng Hock; Heng, Chun-Huat; Lee, Chengkuo

    2016-01-01

    Triboelectric nanogenerators (TENGs) have emerged as a potential solution for mechanical energy harvesting over conventional mechanisms such as piezoelectric and electromagnetic, due to easy fabrication, high efficiency and wider choice of materials. Traditional fabrication techniques used to realize TENGs involve plasma etching, soft lithography and nanoparticle deposition for higher performance. But lack of truly scalable fabrication processes still remains a critical challenge and bottleneck in the path of bringing TENGs to commercial production. In this paper, we demonstrate fabrication of large scale triboelectric nanogenerator (LS-TENG) using roll-to-roll ultraviolet embossing to pattern polyethylene terephthalate sheets. These LS-TENGs can be used to harvest energy from human motion and vehicle motion from embedded devices in floors and roads, respectively. LS-TENG generated a power density of 62.5 mW m−2. Using roll-to-roll processing technique, we also demonstrate a large scale triboelectric pressure sensor array with pressure detection sensitivity of 1.33 V kPa−1. The large scale pressure sensor array has applications in self-powered motion tracking, posture monitoring and electronic skin applications. This work demonstrates scalable fabrication of TENGs and self-powered pressure sensor arrays, which will lead to extremely low cost and bring them closer to commercial production. PMID:26905285

  11. Large Scale Triboelectric Nanogenerator and Self-Powered Pressure Sensor Array Using Low Cost Roll-to-Roll UV Embossing.

    PubMed

    Dhakar, Lokesh; Gudla, Sudeep; Shan, Xuechuan; Wang, Zhiping; Tay, Francis Eng Hock; Heng, Chun-Huat; Lee, Chengkuo

    2016-02-24

    Triboelectric nanogenerators (TENGs) have emerged as a potential solution for mechanical energy harvesting over conventional mechanisms such as piezoelectric and electromagnetic, due to easy fabrication, high efficiency and wider choice of materials. Traditional fabrication techniques used to realize TENGs involve plasma etching, soft lithography and nanoparticle deposition for higher performance. But lack of truly scalable fabrication processes still remains a critical challenge and bottleneck in the path of bringing TENGs to commercial production. In this paper, we demonstrate fabrication of large scale triboelectric nanogenerator (LS-TENG) using roll-to-roll ultraviolet embossing to pattern polyethylene terephthalate sheets. These LS-TENGs can be used to harvest energy from human motion and vehicle motion from embedded devices in floors and roads, respectively. LS-TENG generated a power density of 62.5 mW m(-2). Using roll-to-roll processing technique, we also demonstrate a large scale triboelectric pressure sensor array with pressure detection sensitivity of 1.33 V kPa(-1). The large scale pressure sensor array has applications in self-powered motion tracking, posture monitoring and electronic skin applications. This work demonstrates scalable fabrication of TENGs and self-powered pressure sensor arrays, which will lead to extremely low cost and bring them closer to commercial production.

  12. Roll-to-roll nanopatterning using jet and flash imprint lithography

    NASA Astrophysics Data System (ADS)

    Ahn, Sean; Ganapathisubramanian, Maha; Miller, Mike; Yang, Jack; Choi, Jin; Xu, Frank; Resnick, Douglas J.; Sreenivasan, S. V.

    2012-03-01

    The ability to pattern materials at the nanoscale can enable a variety of applications ranging from high density data storage, displays, photonic devices and CMOS integrated circuits to emerging applications in the biomedical and energy sectors. These applications require varying levels of pattern control, short and long range order, and have varying cost tolerances. Extremely large area R2R manufacturing on flexible substrates is ubiquitous for applications such as paper and plastic processing. It combines the benefits of high speed and inexpensive substrates to deliver a commodity product at low cost. The challenge is to extend this approach to the realm of nanopatterning and realize similar benefits. The cost of manufacturing is typically driven by speed (or throughput), tool complexity, cost of consumables (materials used, mold or master cost, etc.), substrate cost, and the downstream processing required (annealing, deposition, etching, etc.). In order to achieve low cost nanopatterning, it is imperative to move towards high speed imprinting, less complex tools, near zero waste of consumables and low cost substrates. The Jet and Flash Imprint Lithography (J-FILTM) process uses drop dispensing of UV curable resists to assist high resolution patterning for subsequent dry etch pattern transfer. The technology is actively being used to develop solutions for memory markets including Flash memory and patterned media for hard disk drives. In this paper we address the key challenges for roll based nanopatterning by introducing a novel concept: Ink Jet based Roll-to-Roll Nanopatterning. To address this challenge, we have introduced a J-FIL based demonstrator product, the LithoFlex 100. Topics that are discussed in the paper include tool design and process performance. In addition, we have used the LithoFlex 100 to fabricate high performance wire grid polarizers on flexible polycarbonate (PC) films. Transmission of better than 80% and extinction ratios on the order of

  13. The effect of mold materials on the overlay accuracy of a roll-to-roll imprinting system using UV LED illumination within a transparent mold

    NASA Astrophysics Data System (ADS)

    Choi, Sungwoo; Kook, YunHo; Kim, ChulHo; Yoo, SoonSung; Park, Kwon-Shik; Kim, Seok-min; Kang, Shinill

    2016-06-01

    Although several studies on the roll-to-roll (R2R) imprinting process have reported achieving flexible electronics, improving the alignment accuracy in the overlay process of R2R imprinting is recognized as the biggest problem for the commercialization of this technology. For an overlay technique with high alignment accuracy, it is essential to develop a roll mold with high positional accuracy. In this study, a method for fabricating a roll mold with high positional accuracy is proposed by wrapping a thin glass substrate flexible mold around the transparent roll base, because it can provide higher mechanical strength and thermal stability than a conventional polymer substrate. To confirm the usability of the proposed process, the prepared roll mold was used to fabricate a test pattern of thin-film transistor backplane for a rollable display. The positional and overlay accuracy of the roll mold with the proposed thin glass substrate flexible mold were compared with the roll mold with a conventional polymer substrate flexible mold. Large-area transparent flexible molds with a size of 470  ×  370 mm were fabricated by an ultraviolet (UV) imprinting process on thin glass and polyethylene terephthalate substrates, and these flexible molds were wrapped around a roll base of 125 mm radius through a precision alignment process. After an anti-adhesion treatment and the wrapping process, the roll mold with the polymer substrate showed a ~180 μm positional error, whereas the thin glass substrate showed a ~30 μm positional error. After the overlay process using the R2R imprinting system with the alignment system, an average overlay error of ~3 μm was obtained when the thin glass flexible wrapped roll mold was used, whereas a ~22 μm overlay error was obtained when the polymer substrate flexible wrapped roll mold was used.

  14. Large Area 2D and 3D Colloidal Photonic Crystals Fabricated by a Roll-to-Roll Langmuir-Blodgett Method.

    PubMed

    Parchine, Mikhail; McGrath, Joe; Bardosova, Maria; Pemble, Martyn E

    2016-06-14

    We present our results on the fabrication of large area colloidal photonic crystals on flexible poly(ethylene terephthalate) (PET) film using a roll-to-roll Langmuir-Blodgett technique. Two-dimensional (2D) and three-dimensional (3D) colloidal photonic crystals from silica nanospheres (250 and 550 nm diameter) with a total area of up to 340 cm(2) have been fabricated in a continuous manner compatible with high volume manufacturing. In addition, the antireflective properties and structural integrity of the films have been enhanced via the use of a second roll-to-roll process, employing a slot-die coating of an optical adhesive over the photonic crystal films. Scanning electron microscopy images, atomic force microscopy images, and UV-vis optical transmission and reflection spectra of the fabricated photonic crystals are analyzed. This analysis confirms the high quality of the 2D and 3D photonic crystals fabricated by the roll-to-roll LB technique. Potential device applications of the large area 2D and 3D colloidal photonic crystals on flexible PET film are briefly reviewed. PMID:27218474

  15. Large Area 2D and 3D Colloidal Photonic Crystals Fabricated by a Roll-to-Roll Langmuir-Blodgett Method.

    PubMed

    Parchine, Mikhail; McGrath, Joe; Bardosova, Maria; Pemble, Martyn E

    2016-06-14

    We present our results on the fabrication of large area colloidal photonic crystals on flexible poly(ethylene terephthalate) (PET) film using a roll-to-roll Langmuir-Blodgett technique. Two-dimensional (2D) and three-dimensional (3D) colloidal photonic crystals from silica nanospheres (250 and 550 nm diameter) with a total area of up to 340 cm(2) have been fabricated in a continuous manner compatible with high volume manufacturing. In addition, the antireflective properties and structural integrity of the films have been enhanced via the use of a second roll-to-roll process, employing a slot-die coating of an optical adhesive over the photonic crystal films. Scanning electron microscopy images, atomic force microscopy images, and UV-vis optical transmission and reflection spectra of the fabricated photonic crystals are analyzed. This analysis confirms the high quality of the 2D and 3D photonic crystals fabricated by the roll-to-roll LB technique. Potential device applications of the large area 2D and 3D colloidal photonic crystals on flexible PET film are briefly reviewed.

  16. Metal-assisted exfoliation (MAE): green, roll-to-roll compatible method for transferring graphene to flexible substrates

    NASA Astrophysics Data System (ADS)

    Zaretski, Aliaksandr V.; Moetazedi, Herad; Kong, Casey; Sawyer, Eric J.; Savagatrup, Suchol; Valle, Eduardo; O'Connor, Timothy F.; Printz, Adam D.; Lipomi, Darren J.

    2015-01-01

    Graphene is expected to play a significant role in future technologies that span a range from consumer electronics, to devices for the conversion and storage of energy, to conformable biomedical devices for healthcare. To realize these applications, however, a low-cost method of synthesizing large areas of high-quality graphene is required. Currently, the only method to generate large-area single-layer graphene that is compatible with roll-to-roll manufacturing destroys approximately 300 kg of copper foil (thickness = 25 μm) for every 1 g of graphene produced. This paper describes a new environmentally benign and scalable process of transferring graphene to flexible substrates. The process is based on the preferential adhesion of certain thin metallic films to graphene; separation of the graphene from the catalytic copper foil is followed by lamination to a flexible target substrate in a process that is compatible with roll-to-roll manufacturing. The copper substrate is indefinitely reusable and the method is substantially greener than the current process that uses relatively large amounts of corrosive etchants to remove the copper. The sheet resistance of the graphene produced by this new process is unoptimized but should be comparable in principle to that produced by the standard method, given the defects observable by Raman spectroscopy and the presence of process-induced cracks. With further improvements, this green, inexpensive synthesis of single-layer graphene could enable applications in flexible, stretchable, and disposable electronics, low-profile and lightweight barrier materials, and in large-area displays and photovoltaic modules.

  17. Roll-to-roll printed silver nanowires for increased stability of flexible ITO-free organic solar cell modules

    NASA Astrophysics Data System (ADS)

    Dos Reis Benatto, Gisele A.; Roth, Bérenger; Corazza, Michael; Søndergaard, Roar R.; Gevorgyan, Suren A.; Jørgensen, Mikkel; Krebs, Frederik C.

    2015-12-01

    We report the use of roll-to-roll printed silver nanowire networks as front electrodes for fully roll-to-roll processed flexible indium-tin-oxide (ITO) free OPV modules. We prepared devices with two types of back electrodes, a simple PEDOT:PSS back electrode and a PEDOT:PSS back electrode with a printed silver grid in order to simultaneously explore the influence of the back electrode structure on the operational stability of the modules that did not include any UV-protection. We subjected the devices to stability testing under a number of protocols recommended by the international summit on OPV stability (ISOS). We explored accelerated ISOS-D-2, ISOS-D-3, ISOS-L-2, ISOS-L-3, ISOS-O-1 and ISOS-O-2 testing protocols and compared the performance to previous reports employing the same testing protocols on devices with PEDOT:PSS instead of the silver nanowires in the front electrode. We find significantly increased operational stability across all ISOS testing protocols over the course of the study and conclude that replacement of PEDOT:PSS in the front electrode with silver nanowires increase operational stability by up to 1000%. The duration of the tests were in the range of 140-360 days. The comparison of front and back electrode stability in this study shows that the modules with silver nanowire front electrodes together with a composite back electrode comprising PEDOT:PSS and a silver grid present the best operational stability.

  18. Roll-to-roll gravure with nanomaterials for printing smart packaging.

    PubMed

    Jung, Minhun; Kim, Junseok; Koo, Hyunmo; Lee, Wookyu; Subramanian, Vivek; Cho, Gyoujin

    2014-02-01

    Roll-to-roll (R2R) gravure is considered one of the highest throughput tools for manufacturing inexpensive and flexible ubiquitous IT devices called "smart packaging" in which NFC (near-field communication) transponder, sensors, ADC (analog-to-digital converter), simple processor and signage are all integrated on paper or plastic foils. In this review, we show R2R gravure can be employed to print smart packaging, starting from printing simple electrodes, dielectrics, capacitors, diodes and thin film transistors with appropriate nanomaterial-based inks on plastic foils. PMID:24749427

  19. Roll-to-roll gravure with nanomaterials for printing smart packaging.

    PubMed

    Jung, Minhun; Kim, Junseok; Koo, Hyunmo; Lee, Wookyu; Subramanian, Vivek; Cho, Gyoujin

    2014-02-01

    Roll-to-roll (R2R) gravure is considered one of the highest throughput tools for manufacturing inexpensive and flexible ubiquitous IT devices called "smart packaging" in which NFC (near-field communication) transponder, sensors, ADC (analog-to-digital converter), simple processor and signage are all integrated on paper or plastic foils. In this review, we show R2R gravure can be employed to print smart packaging, starting from printing simple electrodes, dielectrics, capacitors, diodes and thin film transistors with appropriate nanomaterial-based inks on plastic foils.

  20. Design and implementation of adaptive PI control schemes for web tension control in roll-to-roll (R2R) manufacturing.

    PubMed

    Raul, Pramod R; Pagilla, Prabhakar R

    2015-05-01

    In this paper, two adaptive Proportional-Integral (PI) control schemes are designed and discussed for control of web tension in Roll-to-Roll (R2R) manufacturing systems. R2R systems are used to transport continuous materials (called webs) on rollers from the unwind roll to the rewind roll. Maintaining web tension at the desired value is critical to many R2R processes such as printing, coating, lamination, etc. Existing fixed gain PI tension control schemes currently used in industrial practice require extensive tuning and do not provide the desired performance for changing operating conditions and material properties. The first adaptive PI scheme utilizes the model reference approach where the controller gains are estimated based on matching of the actual closed-loop tension control systems with an appropriately chosen reference model. The second adaptive PI scheme utilizes the indirect adaptive control approach together with relay feedback technique to automatically initialize the adaptive PI gains. These adaptive tension control schemes can be implemented on any R2R manufacturing system. The key features of the two adaptive schemes is that their designs are simple for practicing engineers, easy to implement in real-time, and automate the tuning process. Extensive experiments are conducted on a large experimental R2R machine which mimics many features of an industrial R2R machine. These experiments include trials with two different polymer webs and a variety of operating conditions. Implementation guidelines are provided for both adaptive schemes. Experimental results comparing the two adaptive schemes and a fixed gain PI tension control scheme used in industrial practice are provided and discussed.

  1. Continuous roll-to-roll a-Si photovoltaic manufacturing technology. Annual subcontractor report, 1 April 1992--31 March 1993

    SciTech Connect

    Izu, M.

    1993-12-01

    This report describes work done under a 3-year program to advance ECD`s roll-to-roll, triple-junction photovoltaic manufacturing technologies, to reduce the module production costs, to increase the stabilized module performance, and to expand commercial capacity utilizing ECD technology. The specific 3-year goal is to develop advanced large-scale manufacturing technology incorporating ECD`s earlier research advances with the capability of producing modules with stable 11% efficiency at a cost of approximately $1.00 per peak watt. Accomplishments during Phase 1 included: (1) ECD successfully incorporated a high-performance Ag/metal-oxide back-reflector system into its continuous roll-to-roll commercial production operation. (2) High-quality a-Si-Ge narrow-band-gap solar cells were incorporated into the manufacturing. (3) ECD demonstrated the continuous roll-to-roll production of high-efficiency, triple-junction, two-band-gap solar cells consistently and uniformly throughout a 762-m (2500-ft) run with high yield. (4) ECD achieved 11.1% initial sub-cell efficiency of triple-junction, two-band-gap a-Si alloy solar cells in the production line. (5) The world`s first 0.37-m{sup 2} (4-ft{sup 2}) PV modules were produced utilizing triple-junction spectrum-splitting solar cells manufactured in the production line. (6) As a result of process optimization to reduce the layer thickness and to improve the gas utilization, ECD achieved a 77% material cost reduction for germane and 58% reduction for disilane. Additionally, ECD developed a new low-cost module that saves approximately 30% in assembly material costs.

  2. Roll-to-roll-compatible, flexible, transparent electrodes based on self-nanoembedded Cu nanowires using intense pulsed light irradiation

    NASA Astrophysics Data System (ADS)

    Zhong, Zhaoyang; Woo, Kyoohee; Kim, Inhyuk; Hwang, Hyewon; Kwon, Sin; Choi, Young-Man; Lee, Youngu; Lee, Taik-Min; Kim, Kwangyoung; Moon, Jooho

    2016-04-01

    Copper nanowire (Cu NW)-based flexible transparent conductive electrodes (FTCEs) have been investigated in detail for use in various applications such as flexible touch screens, organic photovoltaics and organic light-emitting diodes. In this study, hexadecylamine (HDA) adsorbed onto the surface of NWs is changed into polyvinylpyrrolidone (PVP) via a ligand exchange process; the high-molecular-weight PVP enables high dispersion stability. Intense pulsed light (IPL) irradiation is used to remove organic species present on the surface of the NWs and to form direct connections between the NWs rapidly without any atmospheric control. NWs are self-nanoembedded into a plastic substrate after IPL irradiation, which results in a smooth surface, strong NW/substrate adhesion, excellent mechanical flexibility and enhanced oxidation stability. Moreover, Cu NW FTCEs with high uniformities are successfully fabricated on a large area (150 mm × 200 mm) via successive IPL irradiation that is synchronized with the motion of the sample stage. This study demonstrates the possibility of roll-to-roll-based, large-scale production of low-cost, high-performance Cu NW-based FTCEs.Copper nanowire (Cu NW)-based flexible transparent conductive electrodes (FTCEs) have been investigated in detail for use in various applications such as flexible touch screens, organic photovoltaics and organic light-emitting diodes. In this study, hexadecylamine (HDA) adsorbed onto the surface of NWs is changed into polyvinylpyrrolidone (PVP) via a ligand exchange process; the high-molecular-weight PVP enables high dispersion stability. Intense pulsed light (IPL) irradiation is used to remove organic species present on the surface of the NWs and to form direct connections between the NWs rapidly without any atmospheric control. NWs are self-nanoembedded into a plastic substrate after IPL irradiation, which results in a smooth surface, strong NW/substrate adhesion, excellent mechanical flexibility and enhanced

  3. Cotton-textile-enabled flexible self-sustaining power packs via roll-to-roll fabrication.

    PubMed

    Gao, Zan; Bumgardner, Clifton; Song, Ningning; Zhang, Yunya; Li, Jingjing; Li, Xiaodong

    2016-01-01

    With rising energy concerns, efficient energy conversion and storage devices are required to provide a sustainable, green energy supply. Solar cells hold promise as energy conversion devices due to their utilization of readily accessible solar energy; however, the output of solar cells can be non-continuous and unstable. Therefore, it is necessary to combine solar cells with compatible energy storage devices to realize a stable power supply. To this end, supercapacitors, highly efficient energy storage devices, can be integrated with solar cells to mitigate the power fluctuations. Here, we report on the development of a solar cell-supercapacitor hybrid device as a solution to this energy requirement. A high-performance, cotton-textile-enabled asymmetric supercapacitor is integrated with a flexible solar cell via a scalable roll-to-roll manufacturing approach to fabricate a self-sustaining power pack, demonstrating its potential to continuously power future electronic devices.

  4. Cotton-textile-enabled flexible self-sustaining power packs via roll-to-roll fabrication

    PubMed Central

    Gao, Zan; Bumgardner, Clifton; Song, Ningning; Zhang, Yunya; Li, Jingjing; Li, Xiaodong

    2016-01-01

    With rising energy concerns, efficient energy conversion and storage devices are required to provide a sustainable, green energy supply. Solar cells hold promise as energy conversion devices due to their utilization of readily accessible solar energy; however, the output of solar cells can be non-continuous and unstable. Therefore, it is necessary to combine solar cells with compatible energy storage devices to realize a stable power supply. To this end, supercapacitors, highly efficient energy storage devices, can be integrated with solar cells to mitigate the power fluctuations. Here, we report on the development of a solar cell-supercapacitor hybrid device as a solution to this energy requirement. A high-performance, cotton-textile-enabled asymmetric supercapacitor is integrated with a flexible solar cell via a scalable roll-to-roll manufacturing approach to fabricate a self-sustaining power pack, demonstrating its potential to continuously power future electronic devices. PMID:27189776

  5. Transparent Conductive AGZO/Ag/AGZO Multilayers on PET Substrate by Roll-to-Roll Sputtering.

    PubMed

    Kim, Taehoon; Park, Kwangwon; Kim, Jongsu

    2016-02-01

    Indium-free Al and Ga-codoped ZnO (AGZO) multilayer films with nanoscale Ag interlayer were deposited by dual target roll-to-roll RF for AGZO and DC sputtering systems for Ag at room temperature for a large scale. The thicknesses of AGZO/Ag/AGZO multilayer were optimized by changing the roll speed: 0.15/1.1/0.15 m/min for AGZO/Ag/AGZO multilayers, respectively. The optimum thicknesses of AGZO/Ag/AGZO multilayer are 9.21, 8.32 and 8.04 nm, respectively. Optimized AGZO/Ag/AGZO multilayer films showed an excellent transparency (84% at 550 nm) and a low sheet resistance (9.2 omega/sq.) on PET substrates for opto-electronic applications. The effects of nanoscale Ag interlayer on optical and electrical properties of AGZO/Ag/AGZO multilayer films were discussed.

  6. Cotton-textile-enabled flexible self-sustaining power packs via roll-to-roll fabrication

    NASA Astrophysics Data System (ADS)

    Gao, Zan; Bumgardner, Clifton; Song, Ningning; Zhang, Yunya; Li, Jingjing; Li, Xiaodong

    2016-05-01

    With rising energy concerns, efficient energy conversion and storage devices are required to provide a sustainable, green energy supply. Solar cells hold promise as energy conversion devices due to their utilization of readily accessible solar energy; however, the output of solar cells can be non-continuous and unstable. Therefore, it is necessary to combine solar cells with compatible energy storage devices to realize a stable power supply. To this end, supercapacitors, highly efficient energy storage devices, can be integrated with solar cells to mitigate the power fluctuations. Here, we report on the development of a solar cell-supercapacitor hybrid device as a solution to this energy requirement. A high-performance, cotton-textile-enabled asymmetric supercapacitor is integrated with a flexible solar cell via a scalable roll-to-roll manufacturing approach to fabricate a self-sustaining power pack, demonstrating its potential to continuously power future electronic devices.

  7. Transparent Conductive AGZO/Ag/AGZO Multilayers on PET Substrate by Roll-to-Roll Sputtering.

    PubMed

    Kim, Taehoon; Park, Kwangwon; Kim, Jongsu

    2016-02-01

    Indium-free Al and Ga-codoped ZnO (AGZO) multilayer films with nanoscale Ag interlayer were deposited by dual target roll-to-roll RF for AGZO and DC sputtering systems for Ag at room temperature for a large scale. The thicknesses of AGZO/Ag/AGZO multilayer were optimized by changing the roll speed: 0.15/1.1/0.15 m/min for AGZO/Ag/AGZO multilayers, respectively. The optimum thicknesses of AGZO/Ag/AGZO multilayer are 9.21, 8.32 and 8.04 nm, respectively. Optimized AGZO/Ag/AGZO multilayer films showed an excellent transparency (84% at 550 nm) and a low sheet resistance (9.2 omega/sq.) on PET substrates for opto-electronic applications. The effects of nanoscale Ag interlayer on optical and electrical properties of AGZO/Ag/AGZO multilayer films were discussed. PMID:27433648

  8. Cotton-textile-enabled flexible self-sustaining power packs via roll-to-roll fabrication.

    PubMed

    Gao, Zan; Bumgardner, Clifton; Song, Ningning; Zhang, Yunya; Li, Jingjing; Li, Xiaodong

    2016-01-01

    With rising energy concerns, efficient energy conversion and storage devices are required to provide a sustainable, green energy supply. Solar cells hold promise as energy conversion devices due to their utilization of readily accessible solar energy; however, the output of solar cells can be non-continuous and unstable. Therefore, it is necessary to combine solar cells with compatible energy storage devices to realize a stable power supply. To this end, supercapacitors, highly efficient energy storage devices, can be integrated with solar cells to mitigate the power fluctuations. Here, we report on the development of a solar cell-supercapacitor hybrid device as a solution to this energy requirement. A high-performance, cotton-textile-enabled asymmetric supercapacitor is integrated with a flexible solar cell via a scalable roll-to-roll manufacturing approach to fabricate a self-sustaining power pack, demonstrating its potential to continuously power future electronic devices. PMID:27189776

  9. A fully roll-to-roll gravure-printed carbon nanotube-based active matrix for multi-touch sensors

    PubMed Central

    Lee, Wookyu; Koo, Hyunmo; Sun, Junfeng; Noh, Jinsoo; Kwon, Kye-Si; Yeom, Chiseon; Choi, Younchang; Chen, Kevin; Javey, Ali; Cho, Gyoujin

    2015-01-01

    Roll-to-roll (R2R) printing has been pursued as a commercially viable high-throughput technology to manufacture flexible, disposable, and inexpensive printed electronic devices. However, in recent years, pessimism has prevailed because of the barriers faced when attempting to fabricate and integrate thin film transistors (TFTs) using an R2R printing method. In this paper, we report 20 × 20 active matrices (AMs) based on single-walled carbon nanotubes (SWCNTs) with a resolution of 9.3 points per inch (ppi) resolution, obtained using a fully R2R gravure printing process. By using SWCNTs as the semiconducting layer and poly(ethylene terephthalate) (PET) as the substrate, we have obtained a device yield above 98%, and extracted the key scalability factors required for a feasible R2R gravure manufacturing process. Multi-touch sensor arrays were achieved by laminating a pressure sensitive rubber onto the SWCNT-TFT AM. This R2R gravure printing system overcomes the barriers associated with the registration accuracy of printing each layer and the variation of the threshold voltage (Vth). By overcoming these barriers, the R2R gravure printing method can be viable as an advanced manufacturing technology, thus enabling the high-throughput production of flexible, disposable, and human-interactive cutting-edge electronic devices based on SWCNT-TFT AMs. PMID:26635237

  10. A fully roll-to-roll gravure-printed carbon nanotube-based active matrix for multi-touch sensors

    NASA Astrophysics Data System (ADS)

    Lee, Wookyu; Koo, Hyunmo; Sun, Junfeng; Noh, Jinsoo; Kwon, Kye-Si; Yeom, Chiseon; Choi, Younchang; Chen, Kevin; Javey, Ali; Cho, Gyoujin

    2015-12-01

    Roll-to-roll (R2R) printing has been pursued as a commercially viable high-throughput technology to manufacture flexible, disposable, and inexpensive printed electronic devices. However, in recent years, pessimism has prevailed because of the barriers faced when attempting to fabricate and integrate thin film transistors (TFTs) using an R2R printing method. In this paper, we report 20 × 20 active matrices (AMs) based on single-walled carbon nanotubes (SWCNTs) with a resolution of 9.3 points per inch (ppi) resolution, obtained using a fully R2R gravure printing process. By using SWCNTs as the semiconducting layer and poly(ethylene terephthalate) (PET) as the substrate, we have obtained a device yield above 98%, and extracted the key scalability factors required for a feasible R2R gravure manufacturing process. Multi-touch sensor arrays were achieved by laminating a pressure sensitive rubber onto the SWCNT-TFT AM. This R2R gravure printing system overcomes the barriers associated with the registration accuracy of printing each layer and the variation of the threshold voltage (Vth). By overcoming these barriers, the R2R gravure printing method can be viable as an advanced manufacturing technology, thus enabling the high-throughput production of flexible, disposable, and human-interactive cutting-edge electronic devices based on SWCNT-TFT AMs.

  11. A fully roll-to-roll gravure-printed carbon nanotube-based active matrix for multi-touch sensors.

    PubMed

    Lee, Wookyu; Koo, Hyunmo; Sun, Junfeng; Noh, Jinsoo; Kwon, Kye-Si; Yeom, Chiseon; Choi, Younchang; Chen, Kevin; Javey, Ali; Cho, Gyoujin

    2015-12-04

    Roll-to-roll (R2R) printing has been pursued as a commercially viable high-throughput technology to manufacture flexible, disposable, and inexpensive printed electronic devices. However, in recent years, pessimism has prevailed because of the barriers faced when attempting to fabricate and integrate thin film transistors (TFTs) using an R2R printing method. In this paper, we report 20 × 20 active matrices (AMs) based on single-walled carbon nanotubes (SWCNTs) with a resolution of 9.3 points per inch (ppi) resolution, obtained using a fully R2R gravure printing process. By using SWCNTs as the semiconducting layer and poly(ethylene terephthalate) (PET) as the substrate, we have obtained a device yield above 98%, and extracted the key scalability factors required for a feasible R2R gravure manufacturing process. Multi-touch sensor arrays were achieved by laminating a pressure sensitive rubber onto the SWCNT-TFT AM. This R2R gravure printing system overcomes the barriers associated with the registration accuracy of printing each layer and the variation of the threshold voltage (Vth). By overcoming these barriers, the R2R gravure printing method can be viable as an advanced manufacturing technology, thus enabling the high-throughput production of flexible, disposable, and human-interactive cutting-edge electronic devices based on SWCNT-TFT AMs.

  12. Fully roll-to-roll gravure printable wireless (13.56 MHz) sensor-signage tags for smart packaging.

    PubMed

    Kang, Hwiwon; Park, Hyejin; Park, Yongsu; Jung, Minhoon; Kim, Byung Chul; Wallace, Gordon; Cho, Gyoujin

    2014-01-01

    Integration of sensing capabilities with an interactive signage through wireless communication is enabling the development of smart packaging wherein wireless (13.56 MHz) power transmission is used to interlock the smart packaging with a wireless (13.56 MHz) reader or a smart phone. Assembly of the necessary componentry for smart packaging on plastic or paper foils is limited by the manufacturing costs involved with Si based technologies. Here, the issue of manufacturing cost for smart packaging has been obviated by materials that allow R2R (roll-to-roll) gravure in combination with R2R coating processes to be employed. R2R gravure was used to print the wireless power transmission device, called rectenna (antenna, diode and capacitor), and humidity sensor on poly(ethylene terephtalate) (PET) films while electrochromic signage units were fabricated by R2R coating. The signage units were laminated with the R2R gravure printed rectenna and sensor to complete the prototype smart packaging. PMID:24953037

  13. Roll-to-Roll Encapsulation of Metal Nanowires between Graphene and Plastic Substrate for High-Performance Flexible Transparent Electrodes.

    PubMed

    Deng, Bing; Hsu, Po-Chun; Chen, Guanchu; Chandrashekar, B N; Liao, Lei; Ayitimuda, Zhawulie; Wu, Jinxiong; Guo, Yunfan; Lin, Li; Zhou, Yu; Aisijiang, Mahaya; Xie, Qin; Cui, Yi; Liu, Zhongfan; Peng, Hailin

    2015-06-10

    Transparent conductive film on plastic substrate is a critical component in low-cost, flexible, and lightweight optoelectronics. Industrial-scale manufacturing of high-performance transparent conductive flexible plastic is needed to enable wide-ranging applications. Here, we demonstrate a continuous roll-to-roll (R2R) production of transparent conductive flexible plastic based on a metal nanowire network fully encapsulated between graphene monolayer and plastic substrate. Large-area graphene film grown on Cu foil via a R2R chemical vapor deposition process was hot-laminated onto nanowires precoated EVA/PET film, followed by a R2R electrochemical delamination that preserves the Cu foil for reuse. The encapsulated structure minimized the resistance of both wire-to-wire junctions and graphene grain boundaries and strengthened adhesion of nanowires and graphene to plastic substrate, resulting in superior optoelectronic properties (sheet resistance of ∼8 Ω sq(-1) at 94% transmittance), remarkable corrosion resistance, and excellent mechanical flexibility. With these advantages, long-cycle life flexible electrochromic devices are demonstrated, showing up to 10000 cycles.

  14. Fully roll-to-roll gravure printed rectenna on plastic foils for wireless power transmission at 13.56 MHz

    NASA Astrophysics Data System (ADS)

    Park, Hyejin; Kang, Hwiwon; Lee, Yonggil; Park, Yongsu; Noh, Jinsoo; Cho, Gyoujin

    2012-08-01

    Wireless power transmission to inexpensive and disposable smart electronic devices is one of the key issues for the realization of a ubiquitous society where sensor networks such as RFID tags, price tags, smart logos, signage and sensors could be fully interconnected and utilized by DC power of less than 0.3 W. This DC power can be provided by inductively coupled AC from a 13.56 MHz power transmitter through a rectenna, consisting of an antenna, a diode and a capacitor, which would be cheap to integrate with inexpensive smart electronic devices. To integrate the rectenna with a minimum cost, a roll-to-roll (R2R) gravure printing process has been considered to print the rectenna on plastic foils. In this paper, R2R gravure printing systems including printing condition and four different nanoparticle based inks will be reported to print the rectenna (antenna, diode and capacitor) on plastic foils at a printing speed of 8 m min-1 and more than 90% device yield for a wireless power transmission of 0.3 W using a standard 13.56 MHz power transmitter.

  15. Fully roll-to-roll gravure printable wireless (13.56 MHz) sensor-signage tags for smart packaging.

    PubMed

    Kang, Hwiwon; Park, Hyejin; Park, Yongsu; Jung, Minhoon; Kim, Byung Chul; Wallace, Gordon; Cho, Gyoujin

    2014-06-23

    Integration of sensing capabilities with an interactive signage through wireless communication is enabling the development of smart packaging wherein wireless (13.56 MHz) power transmission is used to interlock the smart packaging with a wireless (13.56 MHz) reader or a smart phone. Assembly of the necessary componentry for smart packaging on plastic or paper foils is limited by the manufacturing costs involved with Si based technologies. Here, the issue of manufacturing cost for smart packaging has been obviated by materials that allow R2R (roll-to-roll) gravure in combination with R2R coating processes to be employed. R2R gravure was used to print the wireless power transmission device, called rectenna (antenna, diode and capacitor), and humidity sensor on poly(ethylene terephtalate) (PET) films while electrochromic signage units were fabricated by R2R coating. The signage units were laminated with the R2R gravure printed rectenna and sensor to complete the prototype smart packaging.

  16. Fully Roll-to-Roll Gravure Printable Wireless (13.56 MHz) Sensor-Signage Tags for Smart Packaging

    NASA Astrophysics Data System (ADS)

    Kang, Hwiwon; Park, Hyejin; Park, Yongsu; Jung, Minhoon; Kim, Byung Chul; Wallace, Gordon; Cho, Gyoujin

    2014-06-01

    Integration of sensing capabilities with an interactive signage through wireless communication is enabling the development of smart packaging wherein wireless (13.56 MHz) power transmission is used to interlock the smart packaging with a wireless (13.56 MHz) reader or a smart phone. Assembly of the necessary componentry for smart packaging on plastic or paper foils is limited by the manufacturing costs involved with Si based technologies. Here, the issue of manufacturing cost for smart packaging has been obviated by materials that allow R2R (roll-to-roll) gravure in combination with R2R coating processes to be employed. R2R gravure was used to print the wireless power transmission device, called rectenna (antenna, diode and capacitor), and humidity sensor on poly(ethylene terephtalate) (PET) films while electrochromic signage units were fabricated by R2R coating. The signage units were laminated with the R2R gravure printed rectenna and sensor to complete the prototype smart packaging.

  17. Roll-to-Roll Encapsulation of Metal Nanowires between Graphene and Plastic Substrate for High-Performance Flexible Transparent Electrodes.

    PubMed

    Deng, Bing; Hsu, Po-Chun; Chen, Guanchu; Chandrashekar, B N; Liao, Lei; Ayitimuda, Zhawulie; Wu, Jinxiong; Guo, Yunfan; Lin, Li; Zhou, Yu; Aisijiang, Mahaya; Xie, Qin; Cui, Yi; Liu, Zhongfan; Peng, Hailin

    2015-06-10

    Transparent conductive film on plastic substrate is a critical component in low-cost, flexible, and lightweight optoelectronics. Industrial-scale manufacturing of high-performance transparent conductive flexible plastic is needed to enable wide-ranging applications. Here, we demonstrate a continuous roll-to-roll (R2R) production of transparent conductive flexible plastic based on a metal nanowire network fully encapsulated between graphene monolayer and plastic substrate. Large-area graphene film grown on Cu foil via a R2R chemical vapor deposition process was hot-laminated onto nanowires precoated EVA/PET film, followed by a R2R electrochemical delamination that preserves the Cu foil for reuse. The encapsulated structure minimized the resistance of both wire-to-wire junctions and graphene grain boundaries and strengthened adhesion of nanowires and graphene to plastic substrate, resulting in superior optoelectronic properties (sheet resistance of ∼8 Ω sq(-1) at 94% transmittance), remarkable corrosion resistance, and excellent mechanical flexibility. With these advantages, long-cycle life flexible electrochromic devices are demonstrated, showing up to 10000 cycles. PMID:26020567

  18. Fully roll-to-roll gravure printed rectenna on plastic foils for wireless power transmission at 13.56 MHz.

    PubMed

    Park, Hyejin; Kang, Hwiwon; Lee, Yonggil; Park, Yongsu; Noh, Jinsoo; Cho, Gyoujin

    2012-08-31

    Wireless power transmission to inexpensive and disposable smart electronic devices is one of the key issues for the realization of a ubiquitous society where sensor networks such as RFID tags, price tags, smart logos, signage and sensors could be fully interconnected and utilized by DC power of less than 0.3 W. This DC power can be provided by inductively coupled AC from a 13.56 MHz power transmitter through a rectenna, consisting of an antenna, a diode and a capacitor, which would be cheap to integrate with inexpensive smart electronic devices. To integrate the rectenna with a minimum cost, a roll-to-roll (R2R) gravure printing process has been considered to print the rectenna on plastic foils. In this paper, R2R gravure printing systems including printing condition and four different nanoparticle based inks will be reported to print the rectenna (antenna, diode and capacitor) on plastic foils at a printing speed of 8 m min(-1) and more than 90% device yield for a wireless power transmission of 0.3 W using a standard 13.56 MHz power transmitter. PMID:22885995

  19. Efficiency and Throughput Advances in Continuous Roll-to-Roll a-Si Alloy PV Manufacturing Technology: Final Subcontract Report, 22 June 1998 -- 5 October 2001

    SciTech Connect

    Ellison, T.

    2002-04-01

    This report describes a roll-to-roll triple-junction amorphous silicon alloy PV manufacturing technology developed and commercialized by Energy Conversion Devices (ECD) and United Solar Systems. This low material cost, roll-to-roll production technology has the economies of scale needed to meet the cost goals necessary for widespread use of PV. ECD has developed and built six generations of a-Si production equipment, including the present 5 MW United Solar manufacturing plant in Troy, Michigan. ECD is now designing and building a new 25-MW facility, also in Michigan. United Solar holds the world's record for amorphous silicon PV conversion efficiency, and manufactures and markets a wide range of PV products, including flexible portable modules, power modules, and innovative building-integrated PV (BIPV) shingle and metal-roofing modules that take advantage of this lightweight, rugged, and flexible PV technology. All of United Solar's power and BIPV products are approved by Underwriters Laboratories and carry a 10-year warranty. In this PVMaT 5A subcontract, ECD and United Solar are addressing issues to reduce the cost and improve the manufacturing technology for the ECD/United Solar PV module manufacturing process. ECD and United Solar identified five technology development areas that would reduce the module manufacturing cost in the present 5-MW production facility, and also be applicable to future larger-scale manufacturing facilities.

  20. Web Tension regulation of multispan roll-to-roll system using integrated active dancer and load cells for printed electronics applications

    NASA Astrophysics Data System (ADS)

    Zubair, Muhammad; Ponniah, Ganeshthangaraj; Yang, Young Jin; Choi, Kyung Hyun

    2014-03-01

    The mass production of printed electronics can be achieved by roll-to-roll(R2R) printing system, so highly accurate web tension is required that can minimize the register error and keep the thickness and roughness of printed devices in limits. The web tension of a R2R system is regulated by the use of integrated load cells and active dancer system for printed electronics applications using decentralized multi-input-single-output(MISO) regularized variable learning rate backpropagation artificial neural networks. The active dancer system is used before printing system to reduce disturbances in the web tension of process span. The classical PID control result in tension spikes with the change in roll diameter of winder and unwinder rolls. The presence of dancer in R2R system shows that improved web tension control in printing span and the web tension can be enhanced from 3.75 N to 4.75 N. The overshoot of system is less than ±2.5 N and steady state error is within ±1 N where load cells have a signal noise of ±0.7 N. The integration of load cells and active dancer with self-adapting neural network control provide a solution to the web tension control of multispan roll-to-roll system.

  1. Flexure-based Roll-to-roll Platform: A Practical Solution for Realizing Large-area Microcontact Printing

    PubMed Central

    Zhou, Xi; Xu, Huihua; Cheng, Jiyi; Zhao, Ni; Chen, Shih-Chi

    2015-01-01

    A continuous roll-to-roll microcontact printing (MCP) platform promises large-area nanoscale patterning with significantly improved throughput and a great variety of applications, e.g. precision patterning of metals, bio-molecules, colloidal nanocrystals, etc. Compared with nanoimprint lithography, MCP does not require a thermal imprinting step (which limits the speed and material choices), but instead, extreme precision with multi-axis positioning and misalignment correction capabilities for large area adaptation. In this work, we exploit a flexure-based mechanism that enables continuous MCP with 500 nm precision and 0.05 N force control. The fully automated roll-to-roll platform is coupled with a new backfilling MCP chemistry optimized for high-speed patterning of gold and silver. Gratings of 300, 400, 600 nm line-width at various locations on a 4-inch plastic substrate are fabricated at a speed of 60 cm/min. Our work represents the first example of roll-to-roll MCP with high reproducibility, wafer scale production capability at nanometer resolution. The precision roll-to-roll platform can be readily applied to other material systems. PMID:26037147

  2. Vacuum-thermal-evaporation: the route for roll-to-roll production of large-area organic electronic circuits

    NASA Astrophysics Data System (ADS)

    Taylor, D. M.

    2015-05-01

    Surprisingly little consideration is apparently being given to vacuum-evaporation as the route for the roll-to-roll (R2R) production of large-area organic electronic circuits. While considerable progress has been made by combining silicon lithographic approaches with solution processing, it is not obvious that these will be compatible with a low-cost, high-speed R2R process. Most efforts at achieving this ambition are directed at conventional solution printing approaches such as inkjet and gravure. This is surprising considering that vacuum-evaporation of organic semiconductors (OSCs) is already used commercially in the production of organic light emitting diode displays. Beginning from a discussion of the materials and geometrical parameters determining transistor performance and drawing on results from numerous publications, this review makes a case for vacuum-evaporation as an enabler of R2R organic circuit production. The potential of the vacuum route is benchmarked against solution approaches and found to be highly competitive. For example, evaporated small molecules tend to have higher mobility than printed OSCs. High resolution metal patterning on plastic films is already a low-cost commercial process for high-volume packaging applications. Similarly, solvent-free flash-evaporation and polymerization of thin films on plastic substrates is also a high-volume commercial process and has been shown capable of producing robust gate dielectrics. Reports of basic logic circuit elements produced in a vacuum R2R environment are reviewed and shown to be superior to all-solution printing approaches. Finally, the main issues that need to be resolved in order to fully develop the vacuum route to R2R circuit production are highlighted.

  3. Roll-to-roll production of 30-inch graphene films for transparent electrodes

    NASA Astrophysics Data System (ADS)

    Hong, Byung Hee

    2011-03-01

    The outstanding electrical1, mechanical and chemical properties of graphene make it attractive for applications in flexible electronics. However, efforts to make transparent conducting films from graphene have been hampered by the lack of efficient methods for the synthesis, transfer and doping of graphene at the scale and quality required for applications. Here, we report the roll-to-roll production and wet-chemical doping of predominantly monolayer 30-inch graphene films grown by chemical vapour deposition onto flexible copper substrates. The films have sheet resistances as low as ~ 125 Ohm/sq with 97.4% optical transmittance, and exhibit the half-integer quantum Hall effect, indicating their high quality. We further use layer-by-layer stacking to fabricate a doped four-layer film and measure its sheet resistance at values as low as ~ 30 Ohm/sq at ~ 90 % transparency, which is superior to commercial transparent electrodes such as indium tin oxides. Graphene electrodes were incorporated into a fully functional touch-screen panel device capable of withstanding high strain. Work done in collaboration with Sukang Bae, Hyeongkeun Kim, Youngbin Lee, and Jong-Hyun Ahn, Sungkyunkwan University.

  4. Reduced Blood Coagulation on Roll-to-Roll, Shrink-Induced Superhydrophobic Plastics.

    PubMed

    Nokes, Jolie M; Liedert, Ralph; Kim, Monica Y; Siddiqui, Ali; Chu, Michael; Lee, Eugene K; Khine, Michelle

    2016-03-01

    The unique antiwetting properties of superhydrophobic (SH) surfaces prevent the adhesion of water and bodily fluids, including blood, urine, and saliva. While typical manufacturable approaches to create SH surfaces rely on chemical and structural modifications, such approaches are expensive, require postprocessing, and are often not biocompatible. By contrast, it is demonstrated that purely structural SH features are easily formed using high throughput roll-to-roll (R2R) manufacturing by shrinking a prestressed thermoplastic with a thin, stiff layer of silver and calcium. These features are subsequently embossed into any commercially available and Food and Drug Administration (FDA)-approved plastic. The R2R SH surfaces have contact angles >150° and contact angle hysteresis <10°. Importantly, the surfaces minimize blood adhesion, leading to reduced blood coagulation without the need for anticoagulants. SH surfaces have >4200× reduction of blood residue area compared to the nonstructured controls of the same material. In addition, blood clotting is reduced >5× using whole blood directly from the patient. Furthermore, these surfaces can be easily configured into 3D shapes, as demonstrated with SH tubes. With the simple scale-up production and the eliminated need for anticoagulants to prevent clotting, the proposed conformable SH surfaces can be impactful for a wide range of medical tools, including catheters and microfluidic channels. PMID:26784916

  5. Low-temperature roll-to-roll atmospheric atomic layer deposition of Al₂O₃ thin films.

    PubMed

    Ali, Kamran; Choi, Kyung-Hyun

    2014-12-01

    The Al2O3 thin films deposition through conventional ALD systems is a well-established process. The process under low temperatures has been studied by few research groups. In this paper, we report on the detailed study of low-temperature Al2O3 thin films deposited via a unique in-house built system of roll-to-roll atmospheric atomic layer deposition (R2R-AALD) using a multiple-slit gas source head. Al2O3 thin films have been grown on polyethylene terephthalate substrates under a very low-temperature zone of room temperature to 50 °C and working pressure of 750 Torr, which is very near to atmospheric pressure (760 Torr). Al2O3 thin films with superior properties were achieved in the temperature range of the ALD window. An appreciable growth rate of 0.97 Å/cycle was observed for the films deposited at 40 °C. The films have good morphological features with a very low average arithmetic roughness (Ra) of 0.90 nm. The films also showed good chemical, electrical, and optical characteristics. It was observed that the film characteristics improve with the increase in deposition temperature to the range of the ALD window. The fabrication of Al2O3 films was confirmed by X-ray photoelectron spectroscopy (XPS) analysis with the appearance of Al 2p, Al 2s, and O 1s peaks at the binding energies of 74, 119, and 531 eV, respectively. The chemical composition was also supported by the Fourier transform infrared spectroscopy (FTIR). The fabricated Al2O3 films demonstrate good insulating properties and optical transmittance of more than 85% in the visible region. The results state that Al2O3 thin films can be effectively fabricated through the R2R-AALD system at temperatures as low as 40 °C.

  6. Sub-15 nm linewidth gratings using roll-to-roll nanoimprinting and plasma trimming to fabricate flexible wire-grid polarizers with low colour shift.

    PubMed

    Wu, Chien-Li; Sung, Cheng-Kuo; Yao, Po-Hung; Chen, Cheng-Huan

    2013-07-01

    Sub-15 nm-wide gratings with a high aspect ratio of up to 16:1 were fabricated using roll-to-roll nanoimprinting and plasma trimming to achieve high optical performance (up to 12 000:1 extinction ratio with an average transmittance of 82%) and low colour shift (transmittance variation less than 3%) flexible wire-grid polarizers for display applications. We applied two imprint platforms onto glass and plastic substrates to identify the optical properties and characteristics of each fabrication process. To enhance the tolerance, reproducibility, and optical performance of the process, the grating profile symmetry and varying residual layer thicknesses were precisely simulated and controlled to achieve the design targets.

  7. Continuous roll-to-roll amorphous silicon photovoltaic manufacturing technology. Semiannual subcontract report, 1 April 1993--30 September 1993

    SciTech Connect

    Izu, M

    1994-06-01

    This report describes work for this reporting period under a 3-year program to advance Energy Conversion Device`s (ECD) roll-to-roll, triple-junction photovoltaic (PV) manufacturing technologies, to reduce the module production costs, to increase the stabilized module performance, and to expand commercial production capacity utilizing ECD technology. The specific 3-year goal is to develop advanced large-scale manufacturing technology incorporating ECD`s earlier research advances with the capability of producing modules with stable 11% efficiency at a cost of approximately $1.00 per peak watt. Major accomplishments during this reporting period include (1) the design, construction. amd testomg of a continuous roll-to-roll multipurpose amorphous silicon alloy solar cell deposition machine that incorporates improvements necessary to obtain higher efficiency solar cells; (2) development of a photothermal deflection spectroscopy (PDS) technique for evaluating back-reflector systems; (3) the development of an improved textured Ag/ZnO back-reflector system demonstrating 25% gain in J{sub sc} over previous textured Al back-reflector systems; and (4) the design of a serpentine web continuous roll-to-roll deposition chamber.

  8. Fabrication of flexible oriented magnetic thin films with large in-plane uniaxial anisotropy by roll-to-roll nanoimprint lithography

    NASA Astrophysics Data System (ADS)

    Thantirige, Rukshan M.; John, Jacob; Pradhan, Nihar R.; Carter, Kenneth R.; Tuominen, Mark T.

    2016-06-01

    Here, we report wafer scale fabrication of densely packed Fe nanostripe-based magnetic thin films on a flexible substrate and their magnetic anisotropy properties. We find that Fe nanostripes exhibit large in-plane uniaxial anisotropy and nearly square hysteresis loops with energy products (BHmax) exceeding 3 MGOe at room temperature. High density Fe nanostripes were fabricated on 70 nm flexible polyethylene terephthalate (PET) gratings, which were made by a roll-to-roll (R2R) UV nanoimprint lithography technique. We observed large in-plane uniaxial anisotropies along the long dimension of nanostripes that can be attributed to the shape. Temperature dependent hysteresis measurements confirm that the magnetization reversal is driven by non-coherent rotation reversal processes.

  9. Efficiency and Throughput Advances in Continuous Roll-To-Roll a{_}Si Alloy PV Manufacturing Technology: Phase II Annual Subcontract Technical Report; June 1999--August 2000

    SciTech Connect

    Ellison, T.

    2000-12-07

    This report describes the project by Energy Conversion Devices, Inc. (ECD) and its American joint venture, United Solar Systems Corp. (United Solar), to develop and commercialize a roll-to-roll triple-junction amorphous silicon alloy PV manufacturing technology. This low material cost, roll-to-roll production technology has the economies of scale to meet the cost goals necessary for widespread use of PV. ECD developed and built the present 5-MW United Solar manufacturing plant in Troy, Michigan, and is now designing and building a new 25-MW facility, also in Michigan. United Solar holds the world's record for amorphous silicon PV conversion efficiency, and manufactures and markets a wide range of PV products including flexible portable modules, power modules, and innovative building-integrated PV (BIPV) shingle and metal-roofing modules that take advantage of this lightweight, rugged, and flexible PV technology. All of United Solar's power and BIPV products are approved by Underwriters Laboratories and carry a 10-year warranty. ECD and United Solar are addressing issues to reduce the cost and to improve the manufacturing technology for the ECD/United Solar PV module manufacturing process. ECD and United Solar identified five technology development tasks that would reduce the module manufacturing cost in the present 5-MW production facility and would also be applicable to future larger-scale manufacturing facilities. These development tasks are: Task 5: Improved substrate heating and monitoring systems; Task 6: The development of new on-line diagnostic systems; Task 7: Development of new back-reflector deposition technology; Task 8: Development of improved RF PECVD reactor cathode and gas distribution configurations; and Task 8A: Development of new pinch valve technology.

  10. Roll-to-roll DBD plasma pretreated polyethylene web for enhancement of Al coating adhesion and barrier property

    NASA Astrophysics Data System (ADS)

    Zhang, Haibao; Li, Hua; Fang, Ming; Wang, Zhengduo; Sang, Lijun; Yang, Lizhen; Chen, Qiang

    2016-12-01

    In this paper the roll-to-roll atmospheric dielectric barrier discharge (DBD) was used to pre-treat polyethylene (PE) web surface before the conventional thermal evaporation aluminum (Al) was performed as a barrier layer. We emphasized the plasma environment effect based on the inlet three kinds of reactive monomers. The cross hatch test was employed to assess the Al coating adhesion; and the oxygen transmission rate (OTR) was used to evaluate gas barrier property. The results showed that after roll-to-roll DBD plasma treatment all Al coatings adhered strongly on PE films and were free from pinhole defects with mirror morphology. The OTR was reduced from 2673 cm3/m2 day for Al-coated original PE to 138 cm3/m2 day for Al-coated allyamine (C3H7N) modified PE. To well understand the mechanism the chemical compositions of the untreated and DBD plasma pretreated PE films were analyzed by X-ray photoelectron spectroscopy (XPS). The surface topography was characterized by atomic force microscopy (AFM). For the property of surface energy the water contact angle measurement was also carried out in the DBD plasma treated samples with deionized water.

  11. Design of roll-to-roll printing equipment with multiple printing methods for multi-layer printing.

    PubMed

    Kim, Chung Hwan; Jo, Jeongdai; Lee, Seung-Hyun

    2012-06-01

    In this paper, a novel design concept for roll-to-roll printing equipment used for manufacturing printed electronic devices by multi-layer printing is presented. The roll-to-roll printing system mainly consists of printing units for patterning the circuits, tension control components such as feeders, dancers, load cells, register measurement and control units, and the drying units. It has three printing units which allow switching among the gravure, gravure-offset, and flexo printing methods by changing the web path and the placements of the cylinders. Therefore, depending on the application devices and the corresponding inks used, each printing unit can be easily adjusted to the required printing method. The appropriate printing method can be chosen depending on the desired printing properties such as thickness, roughness, and printing quality. To provide an example of the application of the designed printing equipment, we present the results of printing tests showing the variations in the printing properties of the ink for different printing methods.

  12. Direct and precise measurement of displacement and velocity of flexible web in roll-to-roll manufacturing systems

    SciTech Connect

    Kang, Dongwoo; Lee, Eonseok; Choi, Young-Man; Lee, Taik-Min; Kim, Duk Young; Kim, Dongmin

    2013-12-15

    Interest in the production of printed electronics using a roll-to-roll system has gradually increased due to its low mass-production costs and compatibility with flexible substrate. To improve the accuracy of roll-to-roll manufacturing systems, the movement of the web needs to be measured precisely in advance. In this paper, a novel measurement method is developed to measure the displacement and velocity of the web precisely and directly. The proposed algorithm is based on the traditional single field encoder principle, and the scale grating has been replaced with a printed grating on the web. Because a printed grating cannot be as accurate as a scale grating in a traditional encoder, there will inevitably be variations in pitch and line-width, and the motion of the web should be measured even though there are variations in pitch and line-width in the printed grating patterns. For this reason, the developed algorithm includes a precise method of estimating the variations in pitch. In addtion, a method of correcting the Lissajous curve is presented for precision phase interpolation to improve measurement accuracy by correcting Lissajous circle to unit circle. The performance of the developed method is evaluated by simulation and experiment. In the experiment, the displacement error was less than 2.5 μm and the velocity error of 1σ was about 0.25%, while the grating scale moved 30 mm.

  13. Flexible indium zinc oxide/Ag/indium zinc oxide multilayer electrode grown on polyethersulfone substrate by cost-efficient roll-to-roll sputtering for flexible organic photovoltaics

    SciTech Connect

    Park, Yong-Seok; Kim, Han-Ki

    2010-01-15

    The authors describe the preparation and characteristics of flexible indium zinc oxide (IZO)-Ag-IZO multilayer electrodes grown on flexible polyethersulfone (PES) substrates using a roll-to-roll sputtering system for use in flexible organic photovoltaics. By the continuous roll-to-roll sputtering of the bottom IZO, Ag, and top IZO layers at room temperature, they were able to fabricate a high quality IZO-Ag-IZO multilayer electrode with a sheet resistance of 6.15 {epsilon}/square, optical transmittance of 87.4%, and figure of merit value of 42.03x10{sup -3} {Omega}{sup -1} on the PES substrate. In addition, the IZO-Ag-IZO multilayer electrode exhibited superior flexibility to the roll-to-roll sputter grown single ITO electrode due to the existence of a ductile Ag layer between the IZO layers and stable amorphous structure of the IZO film. Furthermore, the flexible organic solar cells (OSCs) fabricated on the roll-to-roll sputter grown IZO-Ag-IZO electrode showed higher power efficiency (3.51%) than the OSCs fabricated on the roll-to-roll sputter grown single ITO electrode (2.67%).

  14. Roll-To-Roll Process for Transparent Metal Electrodes in OLED Manufacturing

    SciTech Connect

    Slafer, W. Dennis

    2010-06-02

    This program will develop and demonstrate a new manufacturing technology that can help to improve the efficiency and reduce the cost of producing the next generation solid-state lighting (OLEDs)for a broad range of commercial applications. This will not only improve US competitiveness in the manufacturing sector but will also result in a positive impact in meeting the Department of Energy’s goal of developing high efficiency lighting while reducing the environmental impact.

  15. Disposable photonic integrated circuits for evanescent wave sensors by ultra-high volume roll-to-roll method.

    PubMed

    Aikio, Sanna; Hiltunen, Jussi; Hiitola-Keinänen, Johanna; Hiltunen, Marianne; Kontturi, Ville; Siitonen, Samuli; Puustinen, Jarkko; Karioja, Pentti

    2016-02-01

    Flexible photonic integrated circuit technology is an emerging field expanding the usage possibilities of photonics, particularly in sensor applications, by enabling the realization of conformable devices and introduction of new alternative production methods. Here, we demonstrate that disposable polymeric photonic integrated circuit devices can be produced in lengths of hundreds of meters by ultra-high volume roll-to-roll methods on a flexible carrier. Attenuation properties of hundreds of individual devices were measured confirming that waveguides with good and repeatable performance were fabricated. We also demonstrate the applicability of the devices for the evanescent wave sensing of ambient refractive index. The production of integrated photonic devices using ultra-high volume fabrication, in a similar manner as paper is produced, may inherently expand methods of manufacturing low-cost disposable photonic integrated circuits for a wide range of sensor applications.

  16. Disposable photonic integrated circuits for evanescent wave sensors by ultra-high volume roll-to-roll method.

    PubMed

    Aikio, Sanna; Hiltunen, Jussi; Hiitola-Keinänen, Johanna; Hiltunen, Marianne; Kontturi, Ville; Siitonen, Samuli; Puustinen, Jarkko; Karioja, Pentti

    2016-02-01

    Flexible photonic integrated circuit technology is an emerging field expanding the usage possibilities of photonics, particularly in sensor applications, by enabling the realization of conformable devices and introduction of new alternative production methods. Here, we demonstrate that disposable polymeric photonic integrated circuit devices can be produced in lengths of hundreds of meters by ultra-high volume roll-to-roll methods on a flexible carrier. Attenuation properties of hundreds of individual devices were measured confirming that waveguides with good and repeatable performance were fabricated. We also demonstrate the applicability of the devices for the evanescent wave sensing of ambient refractive index. The production of integrated photonic devices using ultra-high volume fabrication, in a similar manner as paper is produced, may inherently expand methods of manufacturing low-cost disposable photonic integrated circuits for a wide range of sensor applications. PMID:26906827

  17. Roll-to-roll fabrication of large scale and regular arrays of three-dimensional nanospikes for high efficiency and flexible photovoltaics

    NASA Astrophysics Data System (ADS)

    Leung, Siu-Fung; Gu, Leilei; Zhang, Qianpeng; Tsui, Kwong-Hoi; Shieh, Jia-Min; Shen, Chang-Hong; Hsiao, Tzu-Hsuan; Hsu, Chin-Hung; Lu, Linfeng; Li, Dongdong; Lin, Qingfeng; Fan, Zhiyong

    2014-03-01

    Three-dimensional (3-D) nanostructures have demonstrated enticing potency to boost performance of photovoltaic devices primarily owning to the improved photon capturing capability. Nevertheless, cost-effective and scalable fabrication of regular 3-D nanostructures with decent robustness and flexibility still remains as a challenging task. Meanwhile, establishing rational design guidelines for 3-D nanostructured solar cells with the balanced electrical and optical performance are of paramount importance and in urgent need. Herein, regular arrays of 3-D nanospikes (NSPs) were fabricated on flexible aluminum foil with a roll-to-roll compatible process. The NSPs have precisely controlled geometry and periodicity which allow systematic investigation on geometry dependent optical and electrical performance of the devices with experiments and modeling. Intriguingly, it has been discovered that the efficiency of an amorphous-Si (a-Si) photovoltaic device fabricated on NSPs can be improved by 43%, as compared to its planar counterpart, in an optimal case. Furthermore, large scale flexible NSP solar cell devices have been fabricated and demonstrated. These results not only have shed light on the design rules of high performance nanostructured solar cells, but also demonstrated a highly practical process to fabricate efficient solar panels with 3-D nanostructures, thus may have immediate impact on thin film photovoltaic industry.

  18. Roll-to-roll fabrication of large scale and regular arrays of three-dimensional nanospikes for high efficiency and flexible photovoltaics.

    PubMed

    Leung, Siu-Fung; Gu, Leilei; Zhang, Qianpeng; Tsui, Kwong-Hoi; Shieh, Jia-Min; Shen, Chang-Hong; Hsiao, Tzu-Hsuan; Hsu, Chin-Hung; Lu, Linfeng; Li, Dongdong; Lin, Qingfeng; Fan, Zhiyong

    2014-03-07

    Three-dimensional (3-D) nanostructures have demonstrated enticing potency to boost performance of photovoltaic devices primarily owning to the improved photon capturing capability. Nevertheless, cost-effective and scalable fabrication of regular 3-D nanostructures with decent robustness and flexibility still remains as a challenging task. Meanwhile, establishing rational design guidelines for 3-D nanostructured solar cells with the balanced electrical and optical performance are of paramount importance and in urgent need. Herein, regular arrays of 3-D nanospikes (NSPs) were fabricated on flexible aluminum foil with a roll-to-roll compatible process. The NSPs have precisely controlled geometry and periodicity which allow systematic investigation on geometry dependent optical and electrical performance of the devices with experiments and modeling. Intriguingly, it has been discovered that the efficiency of an amorphous-Si (a-Si) photovoltaic device fabricated on NSPs can be improved by 43%, as compared to its planar counterpart, in an optimal case. Furthermore, large scale flexible NSP solar cell devices have been fabricated and demonstrated. These results not only have shed light on the design rules of high performance nanostructured solar cells, but also demonstrated a highly practical process to fabricate efficient solar panels with 3-D nanostructures, thus may have immediate impact on thin film photovoltaic industry.

  19. Roll-to-roll fabrication of large scale and regular arrays of three-dimensional nanospikes for high efficiency and flexible photovoltaics.

    PubMed

    Leung, Siu-Fung; Gu, Leilei; Zhang, Qianpeng; Tsui, Kwong-Hoi; Shieh, Jia-Min; Shen, Chang-Hong; Hsiao, Tzu-Hsuan; Hsu, Chin-Hung; Lu, Linfeng; Li, Dongdong; Lin, Qingfeng; Fan, Zhiyong

    2014-01-01

    Three-dimensional (3-D) nanostructures have demonstrated enticing potency to boost performance of photovoltaic devices primarily owning to the improved photon capturing capability. Nevertheless, cost-effective and scalable fabrication of regular 3-D nanostructures with decent robustness and flexibility still remains as a challenging task. Meanwhile, establishing rational design guidelines for 3-D nanostructured solar cells with the balanced electrical and optical performance are of paramount importance and in urgent need. Herein, regular arrays of 3-D nanospikes (NSPs) were fabricated on flexible aluminum foil with a roll-to-roll compatible process. The NSPs have precisely controlled geometry and periodicity which allow systematic investigation on geometry dependent optical and electrical performance of the devices with experiments and modeling. Intriguingly, it has been discovered that the efficiency of an amorphous-Si (a-Si) photovoltaic device fabricated on NSPs can be improved by 43%, as compared to its planar counterpart, in an optimal case. Furthermore, large scale flexible NSP solar cell devices have been fabricated and demonstrated. These results not only have shed light on the design rules of high performance nanostructured solar cells, but also demonstrated a highly practical process to fabricate efficient solar panels with 3-D nanostructures, thus may have immediate impact on thin film photovoltaic industry. PMID:24603964

  20. Fast sintering of silver nanoparticle and flake layers by infrared module assistance in large area roll-to-roll gravure printing system

    PubMed Central

    Park, Janghoon; Kang, Hyi Jae; Shin, Kee-Hyun; Kang, Hyunkyoo

    2016-01-01

    We present fast sintering for silver (Ag) nanoparticle (NP) and flake layers printed using roll-to-roll (R2R) gravure printing. An infrared (IR) sintering module was applied to an R2R system to shorten the sintering duration of an R2R gravure-printed Ag layer. IR sintering of the conductive layer was improved by optimising the process condition. After printing of the Ag NP and Ag flake layers, additional IR sintering was performed in the R2R system. The lowest sheet resistance obtained in the Ag NP layer was 0.294 Ω/□, the distance between the substrate and lamp was 50-mm long, the IR lamp power was 500 W, and the sintering time was 5.4 s. The fastest sintering of 0.34 Ω/□ was achieved with 50-mm distance, 1,000-W IR lamp power, and 1.08-s sintering time. In the Ag flake layer, the lowest sheet resistance obtained was 0.288 Ω/□ with a 20-mm distance, 1,000-W IR lamp power, and 10.8-s sintering time. Meanwhile, the fastest sintering was obtained with a 3.83 Ω/□ sheet resistance, 20-mm distance, 1000-W IR lamp, and 1.08-s sintering time. Thus, the IR sintering module can easily be employed in an R2R system to obtain excellent layer sheet resistance. PMID:27713469

  1. Fast sintering of silver nanoparticle and flake layers by infrared module assistance in large area roll-to-roll gravure printing system

    NASA Astrophysics Data System (ADS)

    Park, Janghoon; Kang, Hyi Jae; Shin, Kee-Hyun; Kang, Hyunkyoo

    2016-10-01

    We present fast sintering for silver (Ag) nanoparticle (NP) and flake layers printed using roll-to-roll (R2R) gravure printing. An infrared (IR) sintering module was applied to an R2R system to shorten the sintering duration of an R2R gravure-printed Ag layer. IR sintering of the conductive layer was improved by optimising the process condition. After printing of the Ag NP and Ag flake layers, additional IR sintering was performed in the R2R system. The lowest sheet resistance obtained in the Ag NP layer was 0.294 Ω/□, the distance between the substrate and lamp was 50-mm long, the IR lamp power was 500 W, and the sintering time was 5.4 s. The fastest sintering of 0.34 Ω/□ was achieved with 50-mm distance, 1,000-W IR lamp power, and 1.08-s sintering time. In the Ag flake layer, the lowest sheet resistance obtained was 0.288 Ω/□ with a 20-mm distance, 1,000-W IR lamp power, and 10.8-s sintering time. Meanwhile, the fastest sintering was obtained with a 3.83 Ω/□ sheet resistance, 20-mm distance, 1000-W IR lamp, and 1.08-s sintering time. Thus, the IR sintering module can easily be employed in an R2R system to obtain excellent layer sheet resistance.

  2. Implementation of a Comprehensive On-Line Closed-Loop Diagnostic System for Roll-to-Roll Amorphous Silicon Solar Cell Production: Annual Report, Year Two; 1 September 2003--31 August 2004

    SciTech Connect

    Ellison, T.

    2005-02-01

    Energy Conversion Devices, Inc. (ECD) has developed and built 7 generations of roll-to-roll amorphous silicon PV production equipment. In the ECD/United Solar Ovonic production process, we deposit about a 1-mm-thick, 12-layer coating consisting of a metal/oxide backreflector, a - layer a-Si/a-SiGe alloy triple-junction solar cell, and a top transparent conductive oxide coating onto 125-mm-thick, 35.5-cm-wide stainless steel webs in a series of three roll-to-roll deposition machines. ECD has now completed the Phase II work for this program. In the following report, we summarize the Phase II work in each of these tasks. We have involved United Solar production personnel in each of these Tasks. This is important for two reasons: Firstly, the collaboration of ECD and United Solar personnel keeps the projects responsive to the developing needs at United Solar. Secondly, most of the tasks affect operations and consequently need the support of United Solar production and QA/QC managers. In the process, we have developed a good working relationship between the production personnel and good balance between optimizing production, while also ''adiabatically'' improving the manufacturing equipment.

  3. Printed polymer photonic devices for optical interconnect systems

    NASA Astrophysics Data System (ADS)

    Subbaraman, Harish; Pan, Zeyu; Zhang, Cheng; Li, Qiaochu; Guo, L. J.; Chen, Ray T.

    2016-03-01

    Polymer photonic device fabrication usually relies on the utilization of clean-room processes, including photolithography, e-beam lithography, reactive ion etching (RIE) and lift-off methods etc, which are expensive and are limited to areas as large as a wafer. Utilizing a novel and a scalable printing process involving ink-jet printing and imprinting, we have fabricated polymer based photonic interconnect components, such as electro-optic polymer based modulators and ring resonator switches, and thermo-optic polymer switch based delay networks and demonstrated their operation. Specifically, a modulator operating at 15MHz and a 2-bit delay network providing up to 35.4ps are presented. In this paper, we also discuss the manufacturing challenges that need to be overcome in order to make roll-to-roll manufacturing practically viable. We discuss a few manufacturing challenges, such as inspection and quality control, registration, and web control, that need to be overcome in order to realize true implementation of roll-to-roll manufacturing of flexible polymer photonic systems. We have overcome these challenges, and currently utilizing our inhouse developed hardware and software tools, <10μm alignment accuracy at a 5m/min is demonstrated. Such a scalable roll-to-roll manufacturing scheme will enable the development of unique optoelectronic devices which can be used in a myriad of different applications, including communication, sensing, medicine, security, imaging, energy, lighting etc.

  4. Fabricating Cu(In,Ga)Se2 solar cells on flexible substrates by a new roll-to-roll deposition system suitable for industrial applications

    NASA Astrophysics Data System (ADS)

    Binetti, S.; Garattini, P.; Mereu, R.; Le Donne, A.; Marchionna, S.; Gasparotto, A.; Meschia, M.; Pinus, I.; Acciarri, M.

    2015-10-01

    In this work, a new hybrid sputtering-evaporation system providing a scalable process for deposition of Cu(In,Ga)Se2 (CIGS) layers is presented. The growth apparatus has been designed and realized to fit a size suitable for direct industrial transfer. In this process the metal precursors are first of all sputtered on rotating transfer devices, then evaporated on the substrate by local heating in a Se atmosphere. The desired thickness and composition of the CIGS film are obtained by repeated sputtering-evaporation cycles. The cylindrical geometry of the deposition chamber has been designed to accommodate different types of flexible substrates with a maximum size of 20 × 120 cm2 in a roll-to-roll configuration. Several techniques, including secondary ion mass spectrometry, Raman and photoluminescence spectroscopies, x-ray diffraction, scanning electron microscopy, external quantum efficiency, and I-V under 1 Sun illumination, have been used to test both the as-grown CIGS layers and the solar cell devices based on them. A significant performance and good control of Ga grading and Na content were obtained for solar cells grown at 450 °C on polyimide substrates with high deposition rates. In spite of the fact that the present efficiency record for CIGS solar cells on polyimide substrates is 20.4%, the 10.1% obtained using the hybrid method presented in this work is significant because the growth apparatus meets the requirements for direct industrial transfer. In fact, this process is being transferred in a 1 MW production line, where standard CIGS layers are deposited at low temperature on flexible substrates in a single-step process with a 1 mm sec-1 substrate velocity.

  5. Roll-to-Roll sputtered ITO/Cu/ITO multilayer electrode for flexible, transparent thin film heaters and electrochromic applications

    PubMed Central

    Park, Sung-Hyun; Lee, Sang-Mok; Ko, Eun-Hye; Kim, Tae-Ho; Nah, Yoon-Chae; Lee, Sang-Jin; Lee, Jae Heung; Kim, Han-Ki

    2016-01-01

    We fabricate high-performance, flexible, transparent electrochromic (EC) films and thin film heaters (TFHs) on an ITO/Cu/ITO (ICI) multilayer electrode prepared by continuous roll-to-roll (RTR) sputtering of ITO and Cu targets. The RTR-sputtered ICI multilayer on a 700 mm wide PET substrate at room temperature exhibits a sheet resistance of 11.8 Ω/square and optical transmittance of 73.9%, which are acceptable for the fabrication of flexible and transparent EC films and TFHs. The effect of the Cu interlayer thickness on the electrical and optical properties of the ICI multilayer was investigated in detail. The bending and cycling fatigue tests demonstrate that the RTR-sputtered ICI multilayer was more flexible than a single ITO film because of high strain failure of the Cu interlayer. The flexible and transparent EC films and TFHs fabricated on the ICI electrode show better performances than reference EC films and TFHs with a single ITO electrode. Therefore, the RTR-sputtered ICI multilayer is the best substitute for the conventional ITO film electrode in order to realize flexible, transparent, cost-effective and large-area EC devices and TFHs that can be used as flexible and smart windows. PMID:27653830

  6. All-solution processed polymer light-emitting diode displays

    NASA Astrophysics Data System (ADS)

    Zheng, Hua; Zheng, Yina; Liu, Nanliu; Ai, Na; Wang, Qing; Wu, Sha; Zhou, Junhong; Hu, Diangang; Yu, Shufu; Han, Shaohu; Xu, Wei; Luo, Chan; Meng, Yanhong; Jiang, Zhixiong; Chen, Yawen; Li, Dongyun; Huang, Fei; Wang, Jian; Peng, Junbiao; Cao, Yong

    2013-06-01

    Adopting the emerging technology of printed electronics in manufacturing novel ultrathin flat panel displays attracts both academic and industrial interests because of the challenge in the device physics and the potential of reducing production costs. Here we produce all-solution processed polymer light-emitting diode displays by solution-depositing the cathode and utilizing a multifunctional buffer layer between the cathode and the organic layers. The use of ink-jetted conducting nanoparticles as the cathode yields high-resolution cathode patterns without any mechanical stress on the organic layers. The buffer layer, which offers the functions of solvent-proof electron injection and proper affinity, is fabricated by mixing the water/alcohol-soluble polymer and a curable epoxy adhesive. Our 1.5-inch polymer light-emitting diode displays are fabricated without any dead pixels or dead lines. The all-solution process eliminates the need for high vacuum for thermal evaporation of the cathode, which paves the way to industrial roll-to-roll manufacturing of flat panel displays.

  7. Millimeter Thin and Rubber-Like Solid-State Lighting Modules Fabricated Using Roll-to-Roll Fluidic Self-Assembly and Lamination.

    PubMed

    Park, Se-Chul; Biswas, Shantonu; Fang, Jun; Mozafari, Mahsa; Stauden, Thomas; Jacobs, Heiko O

    2015-06-24

    A millimeter thin rubber-like solid-state lighting module is reported. The fabrication of the lighting module incorporates assembly and electrical connection of light-emitting diodes (LEDs). The assembly is achieved using a roll-to-roll fluidic self-assembly. The LEDs are sandwiched in-between a stretchable top and bottom electrode to relieve the mechanical stress. The top contact is realized using a lamination technique that eliminates wire-bonding.

  8. Implementation of a Comprehensive On-Line Closed-Loop Diagnostic System for Roll-to-Roll Amorphous Silicon Solar Cell Production: Phase I Annual Report, 23 April 2003--31 August 2003

    SciTech Connect

    Ellison, T.

    2004-08-01

    This subcontract report describes how Energy Conversion Devices, Inc., has developed and built 7 generations of roll-to-roll amorphous silicon PV production equipment. In the ECD/United Solar production process, we deposit about a 1-mm-thick, 12-layer coating consisting of a metal/oxide backreflector, a 9-layer a-Si/a-SiGe alloy triple-junction solar cell, and top transparent conductive oxide coating onto 125-mm-thick, 35.5-cm-wide stainless-steel webs in a series of three roll-to-roll deposition machines. In the PV Manufacturing R&D 6 program, ECD is building upon these accomplishments to enhance the operation of the present production machine, and lay the foundation for improvements in the next-generation machine. ECD has completed the Phase I work for the first two Tasks, and will complete the Phase I work for the second two tasks within the next two months. In the following report, we summarize the Phase I work in each of these tasks. We have involved United Solar production personnel in each of these Tasks. This is important for two reasons: First, the collaboration of ECD and United Solar personnel keeps the projects responsive to the developing needs at United Solar; and most of the tasks affect operations and consequently need the support of United Solar production and QA/QC managers. In the process we have developed a good working relationship between the production personnel, whose mantra is''change nothing,'' and the R&D personnel, who mantra is''change everything.''

  9. Transition from Townsend to radio-frequency homogeneous dielectric barrier discharge in a roll-to-roll configuration

    NASA Astrophysics Data System (ADS)

    Bazinette, R.; Paillol, J.; Massines, F.

    2016-06-01

    The aim of this paper is to better understand the transition from Townsend to radio-frequency homogeneous dielectric barrier discharge (DBD) at atmospheric pressure. The study is done in an Ar/NH3 Penning mixture for an electrode configuration adapted to roll-to-roll plasma surface treatment. The study was led in a frequency range running from 50 kHz up to 8.3 MHz leading to different DBD modes with a 1 mm gas gap: Glow (GDBD), Townsend (TDBD), and Radio-frequency (RF-DBD). In the frequency range between TDBD and RF-DBD, from 250 kHz to 2.3 MHz, additional discharges are observed outside the inter-electrode gas gap. Because each high voltage electrode are inside a dielectric barrel, these additional discharges occur on the side of the barrel where the gap is larger. They disappear when the RF-DBD mode is attained in the 1 mm inter-electrode gas gap, i.e., for frequencies equal or higher than 3 MHz. Fast imaging and optical emission spectroscopy show that the additional discharges are radio-frequency DBDs while the inter-electrode discharge is a TDBD. The RF-DBD discharge mode is attained when electrons drift becomes low enough compared to the voltage oscillation frequency to limit electron loss at the anode. To check that the additional discharges are due to a larger gas gap and a lower voltage amplitude, the TDBD/RF-DBD transition is investigated as a function of the gas gap and the applied voltage frequency and amplitude. Results show that the increase in the frequency at constant gas gap or in the gas gap at constant frequency allows to obtain RF-DBD instead of TDBD. At low frequency and large gap, the increase in the applied voltage allows RF-DBD/TDBD transition. As a consequence, an electrode configuration allowing different gap values is a solution to successively have different discharge modes with the same applied voltage.

  10. Roll-to-roll, shrink-induced superhydrophobic surfaces for antibacterial applications, enhanced point-of-care detection, and blood anticoagulation

    NASA Astrophysics Data System (ADS)

    Nokes, Jolie McLane

    Superhydrophobic (SH) surfaces are desirable because of their unique anti-wetting behavior. Fluid prefers to bead up (contact angle >150°) and roll off (contact angle hysteresis <10°) a SH surface because micro- and nanostructure features trap air pockets. Fluid only adheres to the peaks of the structures, causing minimal adhesion to the surface. Here, shrink-induced SH plastics are fabricated for a plethora of applications, including antibacterial applications, enhanced point-of-care (POC) detection, and reduced blood coagulation. Additionally, these purely structural SH surfaces are achieved in a roll-to-roll (R2R) platform for scalable manufacturing. Because their self-cleaning and water resistant properties, structurally modified SH surfaces prohibit bacterial growth and obviate bacterial chemical resistance. Antibacterial properties are demonstrated in a variety of SH plastics by preventing gram-negative Escherichia coli (E. coli) bacterial growth >150x compared to flat when fluid is rinsed and >20x without rinsing. Therefore, a robust and stable means to prevent bacteria growth is possible. Next, protein in urine is detected using a simple colorimetric output by evaporating droplets on a SH surface. Contrary to evaporation on a flat surface, evaporation on a SH surface allows fluid to dramatically concentrate because the weak adhesion constantly decreases the footprint area. On a SH surface, molecules in solution are confined to a footprint area 8.5x smaller than the original. By concentrating molecules, greater than 160x improvements in detection sensitivity are achieved compared to controls. Utility is demonstrated by detecting protein in urine in the pre-eclampsia range (150-300microgmL -1) for pregnant women. Further, SH surfaces repel bodily fluids including blood, urine, and saliva. Importantly, the surfaces minimize blood adhesion, leading to reduced blood coagulation without the need for anticoagulants. SH surfaces have >4200x and >28x reduction of

  11. Metrology challenges for high-rate nanomanufacturing of polymer structures

    NASA Astrophysics Data System (ADS)

    Mead, Joey; Barry, Carol; Busnaina, Ahmed; Isaacs, Jacqueline

    2012-10-01

    The transfer of nanoscience accomplishments into commercial products is hindered by the lack of understanding of barriers to nanoscale manufacturing. We have developed a number of nanomanufacturing processes that leverage available high-rate plastics fabrication technologies. These processes include directed assembly of a variety of nanoelements, such as nanoparticles and nanotubes, which are then transferred onto a polymer substrate for the fabrication of conformal/flexible electronic materials, among other applications. These assembly processes utilize both electric fields and/or chemical functionalization. Conducting polymers and carbon nanotubes have been successfully transferred to a polymer substrate in times less than 5 minutes, which is commercially relevant and can be utilized in a continuous (reel to reel/roll to roll) process. Other processes include continuous high volume mixing of nanoelements (CNTs, etc) into polymers, multi-layer extrusion and 3D injection molding of polymer structures. These nanomanufacturing processes can be used for wide range of applications, including EMI shielding, flexible electronics, structural materials, and novel sensors (specifically for chem/bio detection). Current techniques to characterize the quality and efficacy of the processes are quite slow. Moreover, the instrumentation and metrology needs for these manufacturing processes are varied and challenging. Novel, rapid, in-line metrology to enable the commercialization of these processes is critically needed. This talk will explore the necessary measurement needs for polymer based nanomanufacturing processes for both step and continuous (reel to reel/roll to roll) processes.

  12. Ultrafast formation of air-processable and high-quality polymer films on an aqueous substrate

    PubMed Central

    Noh, Jonghyeon; Jeong, Seonju; Lee, Jung-Yong

    2016-01-01

    Polymer solar cells are attracting attention as next-generation energy sources. Scalable deposition techniques of high-quality organic films should be guaranteed to realize highly efficient polymer solar cells in large areas for commercial viability. Herein, we introduce an ultrafast, scalable, and versatile process for forming high-quality organic films on an aqueous substrate by utilizing the spontaneous spreading phenomenon. This approach provides easy control over the thickness of the films by tuning the spreading conditions, and the films can be transferred to a variety of secondary substrates. Moreover, the controlled Marangoni flow and ultrafast removal of solvent during the process cause the films to have a uniform, high-quality nanomorphology with finely separated phase domains. Polymer solar cells were fabricated from a mixture of polymer and fullerene derivatives on an aqueous substrate by using the proposed technique, and the device exhibited an excellent power conversion efficiency of 8.44 %. Furthermore, a roll-to-roll production system was proposed as an air-processable and scalable commercial process for fabricating organic devices. PMID:27507624

  13. Ultrafast formation of air-processable and high-quality polymer films on an aqueous substrate

    NASA Astrophysics Data System (ADS)

    Noh, Jonghyeon; Jeong, Seonju; Lee, Jung-Yong

    2016-08-01

    Polymer solar cells are attracting attention as next-generation energy sources. Scalable deposition techniques of high-quality organic films should be guaranteed to realize highly efficient polymer solar cells in large areas for commercial viability. Herein, we introduce an ultrafast, scalable, and versatile process for forming high-quality organic films on an aqueous substrate by utilizing the spontaneous spreading phenomenon. This approach provides easy control over the thickness of the films by tuning the spreading conditions, and the films can be transferred to a variety of secondary substrates. Moreover, the controlled Marangoni flow and ultrafast removal of solvent during the process cause the films to have a uniform, high-quality nanomorphology with finely separated phase domains. Polymer solar cells were fabricated from a mixture of polymer and fullerene derivatives on an aqueous substrate by using the proposed technique, and the device exhibited an excellent power conversion efficiency of 8.44 %. Furthermore, a roll-to-roll production system was proposed as an air-processable and scalable commercial process for fabricating organic devices.

  14. Ultrafast formation of air-processable and high-quality polymer films on an aqueous substrate.

    PubMed

    Noh, Jonghyeon; Jeong, Seonju; Lee, Jung-Yong

    2016-08-10

    Polymer solar cells are attracting attention as next-generation energy sources. Scalable deposition techniques of high-quality organic films should be guaranteed to realize highly efficient polymer solar cells in large areas for commercial viability. Herein, we introduce an ultrafast, scalable, and versatile process for forming high-quality organic films on an aqueous substrate by utilizing the spontaneous spreading phenomenon. This approach provides easy control over the thickness of the films by tuning the spreading conditions, and the films can be transferred to a variety of secondary substrates. Moreover, the controlled Marangoni flow and ultrafast removal of solvent during the process cause the films to have a uniform, high-quality nanomorphology with finely separated phase domains. Polymer solar cells were fabricated from a mixture of polymer and fullerene derivatives on an aqueous substrate by using the proposed technique, and the device exhibited an excellent power conversion efficiency of 8.44 %. Furthermore, a roll-to-roll production system was proposed as an air-processable and scalable commercial process for fabricating organic devices.

  15. Ultrafast formation of air-processable and high-quality polymer films on an aqueous substrate.

    PubMed

    Noh, Jonghyeon; Jeong, Seonju; Lee, Jung-Yong

    2016-01-01

    Polymer solar cells are attracting attention as next-generation energy sources. Scalable deposition techniques of high-quality organic films should be guaranteed to realize highly efficient polymer solar cells in large areas for commercial viability. Herein, we introduce an ultrafast, scalable, and versatile process for forming high-quality organic films on an aqueous substrate by utilizing the spontaneous spreading phenomenon. This approach provides easy control over the thickness of the films by tuning the spreading conditions, and the films can be transferred to a variety of secondary substrates. Moreover, the controlled Marangoni flow and ultrafast removal of solvent during the process cause the films to have a uniform, high-quality nanomorphology with finely separated phase domains. Polymer solar cells were fabricated from a mixture of polymer and fullerene derivatives on an aqueous substrate by using the proposed technique, and the device exhibited an excellent power conversion efficiency of 8.44 %. Furthermore, a roll-to-roll production system was proposed as an air-processable and scalable commercial process for fabricating organic devices. PMID:27507624

  16. Dynamics of the atmospheric pressure diffuse dielectric barrier discharge between cylindrical electrodes in roll-to-roll PECVD reactor

    NASA Astrophysics Data System (ADS)

    Starostin, Sergey A.; Welzel, Stefan; Liu, Yaoge; van der Velden-Schuermans, Bernadette; Bouwstra, Jan B.; van de Sanden, Mauritius C. M.; de Vries, Hindrik W.

    2015-07-01

    The high current diffuse dielectric barrier discharge (DBD) was operated in a bi-axial cylindrical electrode configuration using nitrogen, oxygen and argon gas flow with the addition of tetraethyl orthosilicate as precursor for silica-like film deposition. The behaviour of the transient plasma was visualized by means of fast imaging from two orthogonal directions. The formation and propagation (~3 × 104 m s-1) of lateral ionization waves with the transverse light emission structure similar to the low pressure glow discharge was observed at time scales below 1 µs. Despite plasma non-uniformity at nanosecond time scale the deposition process on the web-rolled polymer results in smooth well adherent films with good film uniformity and excellent gas diffusion barrier properties. Contribution to the topical issue "The 14th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XIV)", edited by Nicolas Gherardi, Ronny Brandenburg and Lars Stollenwark

  17. Printed light-trapping nanorelief Cu electrodes for full-solution-processed flexible organic solar cells

    NASA Astrophysics Data System (ADS)

    Li, Kan; Zhang, Yaokang; Zhen, Hongyu; Niu, Liyong; Fang, Xu; Liu, Zhike; Yan, Feng; Shen, Weidong; Li, Haifeng; Zheng, Zijian

    2016-07-01

    Light-trapping nanorelief metal electrodes have been proven to be an effective approach to improve the absorption performance of flexible organic solar cells (FOSCs). These nanorelief electrodes have been made by conventional vacuum deposition techniques, which are difficult to integrate with roll-to-roll fabrication processes. To address this challenge, this paper reports, for the first time, the fabrication of highly conductive nanorelief Cu electrodes on the flexible substrates through solution printing and polymer-assisted metal deposition at room temperature in the air. FOSCs made with these printed nanorelief Cu electrodes possess not only much improved power conversion efficiency, by 13.5%, but also significant enhancement in flexibility when compared with those made with flat Cu electrodes. Because of the low material and fabrication cost, these printed nanorelief Cu electrodes show great promise in roll-to-roll fabrication of FOSCs in the future.

  18. Large-area perovskite nanowire arrays fabricated by large-scale roll-to-roll micro-gravure printing and doctor blading

    NASA Astrophysics Data System (ADS)

    Hu, Qiao; Wu, Han; Sun, Jia; Yan, Donghang; Gao, Yongli; Yang, Junliang

    2016-02-01

    Organic-inorganic hybrid halide perovskite nanowires (PNWs) show great potential applications in electronic and optoelectronic devices such as solar cells, field-effect transistors and photodetectors. It is very meaningful to fabricate ordered, large-area PNW arrays and greatly accelerate their applications and commercialization in electronic and optoelectronic devices. Herein, highly oriented and ultra-long methylammonium lead iodide (CH3NH3PbI3) PNW array thin films were fabricated by large-scale roll-to-roll (R2R) micro-gravure printing and doctor blading in ambient environments (humility ~45%, temperature ~28 °C), which produced PNW lengths as long as 15 mm. Furthermore, photodetectors based on these PNWs were successfully fabricated on both silicon oxide (SiO2) and flexible polyethylene terephthalate (PET) substrates and showed moderate performance. This study provides low-cost, large-scale techniques to fabricate large-area PNW arrays with great potential applications in flexible electronic and optoelectronic devices.Organic-inorganic hybrid halide perovskite nanowires (PNWs) show great potential applications in electronic and optoelectronic devices such as solar cells, field-effect transistors and photodetectors. It is very meaningful to fabricate ordered, large-area PNW arrays and greatly accelerate their applications and commercialization in electronic and optoelectronic devices. Herein, highly oriented and ultra-long methylammonium lead iodide (CH3NH3PbI3) PNW array thin films were fabricated by large-scale roll-to-roll (R2R) micro-gravure printing and doctor blading in ambient environments (humility ~45%, temperature ~28 °C), which produced PNW lengths as long as 15 mm. Furthermore, photodetectors based on these PNWs were successfully fabricated on both silicon oxide (SiO2) and flexible polyethylene terephthalate (PET) substrates and showed moderate performance. This study provides low-cost, large-scale techniques to fabricate large-area PNW arrays

  19. Large-area perovskite nanowire arrays fabricated by large-scale roll-to-roll micro-gravure printing and doctor blading.

    PubMed

    Hu, Qiao; Wu, Han; Sun, Jia; Yan, Donghang; Gao, Yongli; Yang, Junliang

    2016-03-01

    Organic-inorganic hybrid halide perovskite nanowires (PNWs) show great potential applications in electronic and optoelectronic devices such as solar cells, field-effect transistors and photodetectors. It is very meaningful to fabricate ordered, large-area PNW arrays and greatly accelerate their applications and commercialization in electronic and optoelectronic devices. Herein, highly oriented and ultra-long methylammonium lead iodide (CH3NH3PbI3) PNW array thin films were fabricated by large-scale roll-to-roll (R2R) micro-gravure printing and doctor blading in ambient environments (humility ∼45%, temperature ∼28 °C), which produced PNW lengths as long as 15 mm. Furthermore, photodetectors based on these PNWs were successfully fabricated on both silicon oxide (SiO2) and flexible polyethylene terephthalate (PET) substrates and showed moderate performance. This study provides low-cost, large-scale techniques to fabricate large-area PNW arrays with great potential applications in flexible electronic and optoelectronic devices. PMID:26883938

  20. Roll-to-roll slot-die coating of 400 mm wide, flexible, transparent Ag nanowire films for flexible touch screen panels

    PubMed Central

    Kim, Dong-Ju; Shin, Hae-In; Ko, Eun-Hye; Kim, Ki-Hyun; Kim, Tae-Woong; Kim, Han-Ki

    2016-01-01

    We report fabrication of large area Ag nanowire (NW) film coated using a continuous roll-to-roll (RTR) slot die coater as a viable alternative to conventional ITO electrodes for cost-effective and large-area flexible touch screen panels (TSPs). By controlling the flow rate of shear-thinning Ag NW ink in the slot die, we fabricated Ag NW percolating network films with different sheet resistances (30–70 Ohm/square), optical transmittance values (89–90%), and haze (0.5–1%) percentages. Outer/inner bending, twisting, and rolling tests as well as dynamic fatigue tests demonstrated that the mechanical flexibility of the slot-die coated Ag NW films was superior to that of conventional ITO films. Using diamond-shape patterned Ag NW layer electrodes (50 Ohm/square, 90% optical transmittance), we fabricated 12-inch flexible film-film type and rigid glass-film-film type TSPs. Successful operation of flexible TSPs with Ag NW electrodes indicates that slot-die-coated large-area Ag NW films are promising low cost, high performance, and flexible transparent electrodes for cost-effective large-area flexible TSPs and can be substituted for ITO films, which have high sheet resistance and are brittle. PMID:27677410

  1. Continuous roll-to-roll a-Si photovoltaic manufacturing technology. Semiannual technical progress report, 1 April 1992--30 September 1992

    SciTech Connect

    Izu, M.

    1993-04-01

    This report describes work performed by ECD to advance its roll-to-roll, triple-junction photovoltaic manufacturing technologies; to reduce the module production costs; to increase the stabilized module performance; and to expand the commercial capacity utilizing ECD technology. The 3-year goal is to develop advanced large-scale manufacturing technology incorporating ECD`s earlier research advances with the capability of producing modules with stable 11% efficiency at a cost of approximately $1/W{sub p}. Major efforts during Phase I are (1) the optimization of the high-performance back-reflector system, (2) the optimization of a-Si-Ge narrow band-gap solar cell, and (3) the optimization of the stable efficiency of the module. The goal is to achieve a stable 8% efficient 0.3-m {times} 1.2-m (1-ft {times} 4-ft) module. Also, the efforts include work on a proprietary, high-deposition-rate, microwave plasma, CVD manufacturing technology; and on the investigation of material cost reduction.

  2. Air heating approach for multilayer etching and roll-to-roll transfer of silicon nanowire arrays as SERS substrates for high sensitivity molecule detection.

    PubMed

    Wang, Yan; Zhang, Xiujuan; Gao, Peng; Shao, Zhibin; Zhang, Xiwei; Han, Yuanyan; Jie, Jiansheng

    2014-01-22

    SiNW array represents an attractive system for construction of high-performance energy, electronic, and sensor devices. To meet the demand for flexible devices as well as address the concern about the full use of the Si material, large-area transfer of the SiNW array from growth substrate is very desirable. Here, we report a simple air heating approach to achieve the multilayer etched SiNW array. This method allows the fabrication of up to a five-layer (while perfectly three-layer) cracked SiNW array on single-crystalline Si wafer via a templateless metal-assisted etching approach. Fractures could happen at the crack position when an appropriate pressure was applied on the SiNW array, facilitating the wafer-scale layer-by-layer transfer of the SiNW array onto a flexible substrate through a low-cost and time-efficient roll-to-roll (R2R) technique. Further releasing of the SiNW array to other receiving substrates was accomplished with the aid of a thermal release tape. After modification with sliver nanoparticles (AgNPs), the flexible SiNW array showed great potential as a high-sensitivity surface-enhanced Raman spectroscopy (SERS) substrate for detecting rhodamine 6G (R6G) molecule with concentration as low as 10(-9) M.

  3. Plasma and microwave flash sintering of a tailored silver nanoparticle ink, yielding 60% bulk conductivity on cost-effective polymer foils.

    PubMed

    Perelaer, Jolke; Jani, Robin; Grouchko, Michael; Kamyshny, Alexander; Magdassi, Shlomo; Schubert, Ulrich S

    2012-08-01

    A combination of plasma and microwave flash sintering is used to sinter an inkjet-printed and tailored silver nanoparticle formulation. By using two sintering techniques sequentially, the obtained conductivity is 60%, while keeping the processing temperature well below the glass transition temperature (T(g)) of the used polymer substrate. This approach leads to highly conductive features on cost-effective polymer substrates in relatively short times, which are compatible with roll-to-roll (R2R) production. An electroluminescence device is prepared as an example. PMID:22718319

  4. Recent advances in polymer solar cells: realization of high device performance by incorporating water/alcohol-soluble conjugated polymers as electrode buffer layer.

    PubMed

    He, Zhicai; Wu, Hongbin; Cao, Yong

    2014-02-01

    This Progress Report highlights recent advances in polymer solar cells with special attention focused on the recent rapid-growing progress in methods that use a thin layer of alcohol/water-soluble conjugated polymers as key component to obtain optimized device performance, but also discusses novel materials and device architectures made by major prestigious institutions in this field. We anticipate that due to drastic improvements in efficiency and easy utilization, this method opens up new opportunities for PSCs from various material systems to improve towards 10% efficiency, and many novel device structures will emerge as suitable architectures for developing the ideal roll-to-roll type processing of polymer-based solar cells.

  5. A Course in Polymer Processing.

    ERIC Educational Resources Information Center

    Soong, David S.

    1985-01-01

    A special-topics course in polymer processing has acquired regular course status. Course goals, content (including such new topics as polymer applications in microelectronics), and selected term projects are described. (JN)

  6. Processing polymers with cyclodextrins

    NASA Astrophysics Data System (ADS)

    Williamson, Brandon Robert

    Cyclodextrins (CDs) are cyclic starch molecules that have the unique ability to include a variety of small molecules and polymers inside their cavities, forming "Inclusion Complexes" (ICs). While much work has been done to understand the formation and behavior of these ICs, far less is known about the fundamental property changes that can occur when CD is used to alter polymer chain morphology. The goal of my graduate research has been to discover different ways to improve upon existing polymer properties through CD processing, as well as explore the possibility of creating a novel type of IC using non-traditional forms of cyclodextrin. Poly(ε-caprolactone) (PCL) was processed with alpha-CD to form an IC. The cyclodextrin was then stripped away to yield a PCL with elongated, unentangled, and constrained polymer chains, a process referred to as coalescence. The physical and rheological property changes resulting from this coalescence were then examined. It was found that reorganizing PCL in this manner resulted in an increase in the melt crystallization temperature of up to 25°C. Coalescence also decreased the tan delta of the material and increased the average hardness and Young's modulus by 33 and 53%, respectively. Non-stoichiometric ICs (NS-ICs), or ICs with at least parts of some polymer chains uncovered, were formed between poly (methyl methacrylate) (PMMA) and gamma-CD as well as a synthesized poly(ε-caprolactone)-poly(propylene glycol)-poly(ε-caprolactone) (PCL-PPG-PCL) triblock copolymer and beta-CD. The property changes of the non-complexed polymer chains were then studied. The PMMA/gamma-CD NS-IC samples were determined to be extremely heterogeneous, however glass transition temperature increases of up to 27°C above that of as-received PMMA were observed. Diffraction data for the PMMA NS-ICs suggests slight crystallinity at partial coverage, with a similar crystal structure to that of the fully covered IC. XRD, DSC and FTIR data revealed an almost

  7. FINAL REPORT: Transformational electrode drying process

    SciTech Connect

    Claus Daniel, C.; Wixom, M.

    2013-12-19

    This report includes major findings and outlook from the transformational electrode drying project performance period from January 6, 2012 to August 1, 2012. Electrode drying before cell assembly is an operational bottleneck in battery manufacturing due to long drying times and batch processing. Water taken up during shipment and other manufacturing steps needs to be removed before final battery assembly. Conventional vacuum ovens are limited in drying speed due to a temperature threshold needed to avoid damaging polymer components in the composite electrode. Roll to roll operation and alternative treatments can increase the water desorption and removal rate without overheating and damaging other components in the composite electrode, thus considerably reducing drying time and energy use. The objective of this project was the development of an electrode drying procedure, and the demonstration of processes with no decrease in battery performance. The benchmark for all drying data was an 80°C vacuum furnace treatment with a residence time of 18 – 22 hours. This report demonstrates an alternative roll to roll drying process with a 500-fold improvement in drying time down to 2 minutes and consumption of only 30% of the energy compared to vacuum furnace treatment.

  8. Monolithic amorphous silicon modules on continuous polymer substrate

    SciTech Connect

    Grimmer, D.P. )

    1992-03-01

    This report examines manufacturing monolithic amorphous silicon modules on a continuous polymer substrate. Module production costs can be reduced by increasing module performance, expanding production, and improving and modifying production processes. Material costs can be reduced by developing processes that use a 1-mil polyimide substrate and multilayers of low-cost material for the front encapsulant. Research to speed up a-Si and ZnO deposition rates is needed to improve throughputs. To keep throughput rates compatible with depositions, multibeam fiber optic delivery systems for laser scribing can be used. However, mechanical scribing systems promise even higher throughputs. Tandem cells and production experience can increase device efficiency and stability. Two alternative manufacturing processes are described: (1) wet etching and sheet handling and (2) wet etching and roll-to-roll fabrication.

  9. Critical Issues for Cu(InGa)Se2 Solar Cells on Flexible Polymer Web

    NASA Technical Reports Server (NTRS)

    Eser, Erten; Fields, Shannon; Shafarman, William; Birkmire, Robert

    2007-01-01

    Elemental in-line evaporation on glass substrates has been a viable process for the large-area manufacture of CuInSe2-based photovoltaics, with module efficiencies as high as 12.7% [1]. However, lightweight, flexible CuInSe2-based modules are attractive in a number of applications, such as space power sources. In addition, flexible substrates have an inherent advantage in manufacturability in that they can be deposited in a roll-to-roll configuration allowing continuous, high yield, and ultimately lower cost production. As a result, high-temperature polymers have been used as substrates in depositing CuInSe2 films [2]. Recently, efficiency of 14.1% has been reported for a Cu(InGa)Se2-based solar cell on a polyimide substrate [3]. Both metal foil and polymer webs have been used as substrates for Cu(InGa)Se2-based photovoltaics in a roll-to-roll configuration with reasonable success [4,5]. Both of these substrates do not allow, readily, the incorporation of Na into the Cu(InGa)Se2 film which is necessary for high efficiency devices [3]. In addition, polymer substrates, can not be used at temperatures that are optimum for Cu(InGa)Se2 deposition. However, unlike metal foils, they are electrically insulating, simplifying monolithically-integrated module fabrication and are not a source of impurities diffusing into the growing film. The Institute of Energy Conversion (IEC) has modified its in-line evaporation system [6] from deposition onto glass substrates to roll-to-roll deposition onto polyimide (PI) film in order to investigate key issues in the deposition of large-area Cu(InGa)Se2 films on flexible polymer substrates. This transition presented unexpected challenges that had to be resolved. In this paper, two major problems, spitting from the Cu source and the cracking of Mo back contact film, will be discussed and the solution to each will be presented.

  10. Effect of Ar Ion Beam Pre-Treatment of Poly(ethylene terephthalate) Substrate on the Mechanical and Electrical Stability of Flexible InSnO Films Grown by Roll-to-Roll Sputtering System

    NASA Astrophysics Data System (ADS)

    Choi, Kwang-Hyuk; Kim, Han-Ki

    2013-10-01

    We investigated the effects of Ar ion beam irradiation on a flexible poly(ethylene terephthalate) (PET) substrate as surface pre-treatment method in the roll-to-roll (R2R) sputtering system and its contribution to the electrical durability of flexible InSnO (ITO) electrode upon that the flexible PET substrate under repeated mechanical stresses. It was found that the Ar ion beam irradiation of the flexible PET surface could improve an adhesion between R2R sputter-grown ITO film and the PET substrate. X-ray photoelectron spectroscopy results showed that the Ar ion beam irradiation lead to an increase of hydrophilic functional groups when the working pressure, Ar ion beam power, and exposure time increases. Repetitive bending stresses for the flexible ITO/PET film which fabricated through the surface pre-treatment by Ar ion beam irradiation showed more stable electrical durability than those of ITO films on the wet-cleaned PET substrate due to enhanced interfacial adhesion between the ITO film and PET surface. This suggests that the Ar ion beam pre-treatment before sputtering of ITO film in R2R sputtering system is an effective technique to improve the adhesion between ITO film and PET substrate.

  11. Efficiency and throughput advances in continuous roll-to-roll a-Si alloy PV manufacturing technology: Annual technical progress report: 22 June 1998--21 June 1999

    SciTech Connect

    Izu, M.

    1999-11-09

    This document reports on work performed by Energy Conversion Devices, Inc. (ECD) during Phase 1 of this subcontract. During this period, ECD researchers: (1) Completed design and construction of new, improved substrate heater; (2) Tested and verified improved performance of the new substrate heater in the pilot machine; (3) Verified improved performance of the new substrate heater in the production machine; (4) Designed and bench-tested a new infrared temperature sensor; (5) Installed a prototype new infrared temperature sensor in the production machine for evaluation; (6) Designed a new rolling thermocouple temperature sensor; (7) Designed and bench-tested a reflectometer for the backreflector deposition machine; (8) Designed and bench-tested in-line non-contacting cell diagnostic sensor and PV capacitive diagnostic system; (9) Installed the in-line cell diagnostic sensor in the 5-MW a-Si deposition machine for evaluation; (10) Demonstrated a new low-cost zinc metal process in the pilot back reflector machine; and (11) Fully tested a new cathode design for improved uniformity.

  12. Molding process for imidazopyrrolone polymers

    NASA Technical Reports Server (NTRS)

    Johnson, C. L. (Inventor)

    1973-01-01

    A process is described for producing shaped articles of imidazopyrrolone polymers comprising molding imidazopyrrolone polymer molding power under pressure and at a temperature greater than 475 C. Moderate pressures may be employed. Preferably, prior to molding, a preform is prepared by isostatic compression. The preform may be molded at a relatively low initial pressure and temperature; as the temperature is increased to a value greater than 475 C., the pressure is also increased.

  13. Improving organic tandem solar cells based on water-processed nanoparticles by quantitative 3D nanoimaging.

    PubMed

    Pedersen, E B L; Angmo, D; Dam, H F; Thydén, K T S; Andersen, T R; Skjønsfjell, E T B; Krebs, F C; Holler, M; Diaz, A; Guizar-Sicairos, M; Breiby, D W; Andreasen, J W

    2015-08-28

    Organic solar cells have great potential for upscaling due to roll-to-roll processing and a low energy payback time, making them an attractive sustainable energy source for the future. Active layers coated with water-dispersible Landfester particles enable greater control of the layer formation and easier access to the printing industry, which has reduced the use of organic solvents since the 1980s. Through ptychographic X-ray computed tomography (PXCT), we image quantitatively a roll-to-roll coated photovoltaic tandem stack consisting of one bulk heterojunction active layer and one Landfester particle active layer. We extract the layered morphology with structural and density information including the porosity present in the various layers and the silver electrode with high resolution in 3D. The Landfester particle layer is found to have an undesired morphology with negatively correlated top- and bottom interfaces, wide thickness distribution and only partial surface coverage causing electric short circuits through the layer. By top coating a polymer material onto the Landfester nanoparticles we eliminate the structural defects of the layer such as porosity and roughness, and achieve the increased performance larger than 1 V expected for a tandem cell. This study highlights that quantitative imaging of weakly scattering stacked layers of organic materials has become feasible by PXCT, and that this information cannot be obtained by other methods. In the present study, this technique specifically reveals the need to improve the coatability and layer formation of Landfester nanoparticles, thus allowing improved solar cells to be produced. PMID:26220159

  14. Large-scale ordering of nanoparticles using viscoelastic shear processing

    PubMed Central

    Zhao, Qibin; Finlayson, Chris E.; Snoswell, David R. E.; Haines, Andrew; Schäfer, Christian; Spahn, Peter; Hellmann, Goetz P.; Petukhov, Andrei V.; Herrmann, Lars; Burdet, Pierre; Midgley, Paul A.; Butler, Simon; Mackley, Malcolm; Guo, Qixin; Baumberg, Jeremy J.

    2016-01-01

    Despite the availability of elaborate varieties of nanoparticles, their assembly into regular superstructures and photonic materials remains challenging. Here we show how flexible films of stacked polymer nanoparticles can be directly assembled in a roll-to-roll process using a bending-induced oscillatory shear technique. For sub-micron spherical nanoparticles, this gives elastomeric photonic crystals termed polymer opals showing extremely strong tunable structural colour. With oscillatory strain amplitudes of 300%, crystallization initiates at the wall and develops quickly across the bulk within only five oscillations. The resulting structure of random hexagonal close-packed layers is improved by shearing bidirectionally, alternating between two in-plane directions. Our theoretical framework indicates how the reduction in shear viscosity with increasing order of each layer accounts for these results, even when diffusion is totally absent. This general principle of shear ordering in viscoelastic media opens the way to manufacturable photonic materials, and forms a generic tool for ordering nanoparticles. PMID:27255808

  15. Large-scale ordering of nanoparticles using viscoelastic shear processing.

    PubMed

    Zhao, Qibin; Finlayson, Chris E; Snoswell, David R E; Haines, Andrew; Schäfer, Christian; Spahn, Peter; Hellmann, Goetz P; Petukhov, Andrei V; Herrmann, Lars; Burdet, Pierre; Midgley, Paul A; Butler, Simon; Mackley, Malcolm; Guo, Qixin; Baumberg, Jeremy J

    2016-01-01

    Despite the availability of elaborate varieties of nanoparticles, their assembly into regular superstructures and photonic materials remains challenging. Here we show how flexible films of stacked polymer nanoparticles can be directly assembled in a roll-to-roll process using a bending-induced oscillatory shear technique. For sub-micron spherical nanoparticles, this gives elastomeric photonic crystals termed polymer opals showing extremely strong tunable structural colour. With oscillatory strain amplitudes of 300%, crystallization initiates at the wall and develops quickly across the bulk within only five oscillations. The resulting structure of random hexagonal close-packed layers is improved by shearing bidirectionally, alternating between two in-plane directions. Our theoretical framework indicates how the reduction in shear viscosity with increasing order of each layer accounts for these results, even when diffusion is totally absent. This general principle of shear ordering in viscoelastic media opens the way to manufacturable photonic materials, and forms a generic tool for ordering nanoparticles. PMID:27255808

  16. Large-scale ordering of nanoparticles using viscoelastic shear processing.

    PubMed

    Zhao, Qibin; Finlayson, Chris E; Snoswell, David R E; Haines, Andrew; Schäfer, Christian; Spahn, Peter; Hellmann, Goetz P; Petukhov, Andrei V; Herrmann, Lars; Burdet, Pierre; Midgley, Paul A; Butler, Simon; Mackley, Malcolm; Guo, Qixin; Baumberg, Jeremy J

    2016-06-03

    Despite the availability of elaborate varieties of nanoparticles, their assembly into regular superstructures and photonic materials remains challenging. Here we show how flexible films of stacked polymer nanoparticles can be directly assembled in a roll-to-roll process using a bending-induced oscillatory shear technique. For sub-micron spherical nanoparticles, this gives elastomeric photonic crystals termed polymer opals showing extremely strong tunable structural colour. With oscillatory strain amplitudes of 300%, crystallization initiates at the wall and develops quickly across the bulk within only five oscillations. The resulting structure of random hexagonal close-packed layers is improved by shearing bidirectionally, alternating between two in-plane directions. Our theoretical framework indicates how the reduction in shear viscosity with increasing order of each layer accounts for these results, even when diffusion is totally absent. This general principle of shear ordering in viscoelastic media opens the way to manufacturable photonic materials, and forms a generic tool for ordering nanoparticles.

  17. Large-scale ordering of nanoparticles using viscoelastic shear processing

    NASA Astrophysics Data System (ADS)

    Zhao, Qibin; Finlayson, Chris E.; Snoswell, David R. E.; Haines, Andrew; Schäfer, Christian; Spahn, Peter; Hellmann, Goetz P.; Petukhov, Andrei V.; Herrmann, Lars; Burdet, Pierre; Midgley, Paul A.; Butler, Simon; Mackley, Malcolm; Guo, Qixin; Baumberg, Jeremy J.

    2016-06-01

    Despite the availability of elaborate varieties of nanoparticles, their assembly into regular superstructures and photonic materials remains challenging. Here we show how flexible films of stacked polymer nanoparticles can be directly assembled in a roll-to-roll process using a bending-induced oscillatory shear technique. For sub-micron spherical nanoparticles, this gives elastomeric photonic crystals termed polymer opals showing extremely strong tunable structural colour. With oscillatory strain amplitudes of 300%, crystallization initiates at the wall and develops quickly across the bulk within only five oscillations. The resulting structure of random hexagonal close-packed layers is improved by shearing bidirectionally, alternating between two in-plane directions. Our theoretical framework indicates how the reduction in shear viscosity with increasing order of each layer accounts for these results, even when diffusion is totally absent. This general principle of shear ordering in viscoelastic media opens the way to manufacturable photonic materials, and forms a generic tool for ordering nanoparticles.

  18. Advanced Polymer Processing Facility

    SciTech Connect

    Muenchausen, Ross E.

    2012-07-25

    Some conclusions of this presentation are: (1) Radiation-assisted nanotechnology applications will continue to grow; (2) The APPF will provide a unique focus for radiolytic processing of nanomaterials in support of DOE-DP, other DOE and advanced manufacturing initiatives; (3) {gamma}, X-ray, e-beam and ion beam processing will increasingly be applied for 'green' manufacturing of nanomaterials and nanocomposites; and (4) Biomedical science and engineering may ultimately be the biggest application area for radiation-assisted nanotechnology development.

  19. Polymer-assisted metal deposition (PAMD): a full-solution strategy for flexible, stretchable, compressible, and wearable metal conductors.

    PubMed

    Yu, You; Yan, Casey; Zheng, Zijian

    2014-08-20

    Metal interconnects, contacts, and electrodes are indispensable elements for most applications of flexible, stretchable, and wearable electronics. Current fabrication methods for these metal conductors are mainly based on conventional microfabrication procedures that have been migrated from Si semiconductor industries, which face significant challenges for organic-based compliant substrates. This Research News highlights a recently developed full-solution processing strategy, polymer-assisted metal deposition (PAMD), which is particularly suitable for the roll-to-roll, low-cost fabrication of high-performance compliant metal conductors (Cu, Ni, Ag, and Au) on a wide variety of organic substrates including plastics, elastomers, papers, and textiles. This paper presents i) the principles of PAMD, and how to use it for making ii) flexible, stretchable, and wearable conductive metal electrodes, iii) patterned metal interconnects, and d) 3D stretchable and compressible metal sponges. A critical perspective on this emerging strategy is also provided. PMID:24458846

  20. Laser-induced porous graphene films from commercial polymers

    PubMed Central

    Lin, Jian; Peng, Zhiwei; Liu, Yuanyue; Ruiz-Zepeda, Francisco; Ye, Ruquan; Samuel, Errol L. G.; Yacaman, Miguel Jose; Yakobson, Boris I.; Tour, James M.

    2014-01-01

    Synthesis and patterning of carbon nanomaterials cost effectively is a challenge in electronic and energy storage devices. Here report a one-step, scalable approach for producing and patterning porous graphene films with 3-dimensional networks from commercial polymer films using a CO2 infrared laser. The sp3-carbon atoms are photothermally converted to sp2-carbon atoms by pulsed laser irradiation. The resulting laser-induced graphene (LIG) exhibits high electrical conductivity. The LIG can be readily patterned to interdigitated electrodes for in-plane microsupercapacitors with specific capacitances of >4 mF·cm−2 and power densities of ~9 mW·cm−2. Theoretical calculations partially suggest that enhanced capacitance may result from LIG’s unusual ultra-polycrystalline lattice of pentagon-heptagon structures. Combined with the advantage of one-step processing of LIG in air from commercial polymer sheets, which would allow the employment of a roll-to-roll manufacturing process, this technique provides a rapid route to polymer-written electronic and energy storage devices. PMID:25493446

  1. Laser-induced porous graphene films from commercial polymers.

    PubMed

    Lin, Jian; Peng, Zhiwei; Liu, Yuanyue; Ruiz-Zepeda, Francisco; Ye, Ruquan; Samuel, Errol L G; Yacaman, Miguel Jose; Yakobson, Boris I; Tour, James M

    2014-01-01

    The cost effective synthesis and patterning of carbon nanomaterials is a challenge in electronic and energy storage devices. Here we report a one-step, scalable approach for producing and patterning porous graphene films with three-dimensional networks from commercial polymer films using a CO2 infrared laser. The sp(3)-carbon atoms are photothermally converted to sp(2)-carbon atoms by pulsed laser irradiation. The resulting laser-induced graphene (LIG) exhibits high electrical conductivity. The LIG can be readily patterned to interdigitated electrodes for in-plane microsupercapacitors with specific capacitances of >4 mF cm(-2) and power densities of ~9 mW cm(-2). Theoretical calculations partially suggest that enhanced capacitance may result from LIG's unusual ultra-polycrystalline lattice of pentagon-heptagon structures. Combined with the advantage of one-step processing of LIG in air from commercial polymer sheets, which would allow the employment of a roll-to-roll manufacturing process, this technique provides a rapid route to polymer-written electronic and energy storage devices. PMID:25493446

  2. A high-order external distributed feedback polymer laser with low working threshold

    NASA Astrophysics Data System (ADS)

    Huang, Wenbin; Pu, Donglin; Yang, Xiaofei; Wei, Guojun; Fang, Zongbao; Zhou, Xiaohong; Qiao, Wen; Chen, Linsen

    2016-05-01

    In this paper, we report a high-order distributed feedback (DFB) polymer laser with low working threshold. Using the high-order grating increases the lithographic tolerances, providing coherent light sources that are more amenable to mass-manufacturing techniques, such as laser direct writing lithography and roll-to-roll processing. To enable high-order DFB lasing, an unconventional working configuration is designed in which the grating is situated on top of the uniform conjugated polymer film. In addition, a novel Forster energy transfer blend of two conjugated polymers is used as the gain medium. Upon pumping, the device emits lasing around 603.6 nm with a bandwidth of 0.5 nm. The threshold is around 20.5 μJ cm-2 (~2.56 kW cm-2), about to enter the regime of inexpensive LED pumping. A further increase in pump energy results in simultaneous oscillations at the 29th and 30th Bragg orders. Operating principles of the high-order DFB polymer laser, including spectral performance and threshold dependence on pump length, are investigated. This approach represents a step towards low-cost, even ‘disposable’ polymer lasers.

  3. A high-order external distributed feedback polymer laser with low working threshold

    NASA Astrophysics Data System (ADS)

    Huang, Wenbin; Pu, Donglin; Yang, Xiaofei; Wei, Guojun; Fang, Zongbao; Zhou, Xiaohong; Qiao, Wen; Chen, Linsen

    2016-05-01

    In this paper, we report a high-order distributed feedback (DFB) polymer laser with low working threshold. Using the high-order grating increases the lithographic tolerances, providing coherent light sources that are more amenable to mass-manufacturing techniques, such as laser direct writing lithography and roll-to-roll processing. To enable high-order DFB lasing, an unconventional working configuration is designed in which the grating is situated on top of the uniform conjugated polymer film. In addition, a novel Forster energy transfer blend of two conjugated polymers is used as the gain medium. Upon pumping, the device emits lasing around 603.6 nm with a bandwidth of 0.5 nm. The threshold is around 20.5 μJ cm‑2 (~2.56 kW cm‑2), about to enter the regime of inexpensive LED pumping. A further increase in pump energy results in simultaneous oscillations at the 29th and 30th Bragg orders. Operating principles of the high-order DFB polymer laser, including spectral performance and threshold dependence on pump length, are investigated. This approach represents a step towards low-cost, even ‘disposable’ polymer lasers.

  4. Process for preparing polymer reinforced silica aerogels

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B. (Inventor); Capadona, Lynn A. (Inventor)

    2011-01-01

    Process for preparing polymer-reinforced silica aerogels which comprises a one-pot reaction of at least one alkoxy silane in the presence of effective amounts of a polymer precursor to obtain a silica reaction product, the reaction product is gelled and subsequently subjected to conditions that promotes polymerization of the precursor and then supercritically dried to obtain the polymer-reinforced monolithic silica aerogels.

  5. Improving organic tandem solar cells based on water-processed nanoparticles by quantitative 3D nanoimaging

    NASA Astrophysics Data System (ADS)

    Pedersen, E. B. L.; Angmo, D.; Dam, H. F.; Thydén, K. T. S.; Andersen, T. R.; Skjønsfjell, E. T. B.; Krebs, F. C.; Holler, M.; Diaz, A.; Guizar-Sicairos, M.; Breiby, D. W.; Andreasen, J. W.

    2015-08-01

    Organic solar cells have great potential for upscaling due to roll-to-roll processing and a low energy payback time, making them an attractive sustainable energy source for the future. Active layers coated with water-dispersible Landfester particles enable greater control of the layer formation and easier access to the printing industry, which has reduced the use of organic solvents since the 1980s. Through ptychographic X-ray computed tomography (PXCT), we image quantitatively a roll-to-roll coated photovoltaic tandem stack consisting of one bulk heterojunction active layer and one Landfester particle active layer. We extract the layered morphology with structural and density information including the porosity present in the various layers and the silver electrode with high resolution in 3D. The Landfester particle layer is found to have an undesired morphology with negatively correlated top- and bottom interfaces, wide thickness distribution and only partial surface coverage causing electric short circuits through the layer. By top coating a polymer material onto the Landfester nanoparticles we eliminate the structural defects of the layer such as porosity and roughness, and achieve the increased performance larger than 1 V expected for a tandem cell. This study highlights that quantitative imaging of weakly scattering stacked layers of organic materials has become feasible by PXCT, and that this information cannot be obtained by other methods. In the present study, this technique specifically reveals the need to improve the coatability and layer formation of Landfester nanoparticles, thus allowing improved solar cells to be produced.Organic solar cells have great potential for upscaling due to roll-to-roll processing and a low energy payback time, making them an attractive sustainable energy source for the future. Active layers coated with water-dispersible Landfester particles enable greater control of the layer formation and easier access to the printing

  6. Molecular Processing of Polymers with Cyclodextrins

    NASA Astrophysics Data System (ADS)

    Tonelli, Alan E.

    We summarize our recent studies employing the cyclic starch derivatives called cyclodextrins (CDs) to both nanostructure and functionalize polymers. Two important structural characteristics of CDs are taken advantage of to achieve these goals. First the ability of CDs to form noncovalent inclusion complexes (ICs) with a variety of guest molecules, including many polymers, by threading and inclusion into their relatively hydrophobic interior cavities, which are roughly cylindrical with diameters of ˜ 0.5 - 1.0 nm. α-, β-, and γ-CD contain six, seven, and eight α-1,4-linked glucose units, respectively. Warm water washing of polymer-CD-ICs containing polymer guests insoluble in water or treatment with amylase enzymes serves to remove the host CDs and results in the coalescence of the guest polymers into solid samples. When guest polymers are coalesced from the CD-ICs by removing their host CDs, they are observed to solidify with structures, morphologies, and even conformations that are distinct from bulk samples made from their solutions and melts. Molecularly mixed, intimate blends of two or more polymers that are normally immiscible can be obtained from their common CD-ICs, and the phase segregation of incompatible blocks can be controlled (suppressed or increased) in CD-IC coalesced block copolymers. In addition, additives may be more effectively delivered to polymers in the form of their crystalline CD-ICs or soluble CD-rotaxanes. Secondly, the many hydroxyl groups attached to the exterior rims of CDs, in addition to conferring water solubility, provide an opportunity to covalently bond them to polymers either during their syntheses or via postpolymerization reactions. Polymers containing CDs in their backbones or attached to their side chains are observed to more readily accept and retain additives, such as dyes and fragrances. Processing with CDs can serve to both nanostructure and functionalize polymers, leading to greater understanding of their behaviors

  7. CRADA final report: Technical assessment of roll-to-roll operation of lamination process, thermal treatment, and alternative carbon fiber precursors for low-cost, high-efficiency manufacturing of flow battery stacks and other energy devices

    SciTech Connect

    Daniel, Claus; Madden, Thomas; Wood, III, David L; Muth, Thomas R.; Warrington, Curtis; Ozcan, Soydan; Manson, Hunter; Tekinalp, Halil L.; Smith, Mark A.; Lu, Yuan; Loretz, Jeremy

    2015-09-23

    Among the various stationary-storage technologies under development, redox flow batteries (RFBs) offer the greatest potential to deliver inexpensive, scalable, and efficient grid-scale electrical-energy storage. Unlike traditional sealed batteries, in a flow battery power and energy are decoupled. Cell area and cell count in the stack determine the device power, and the chemical storage volume determines the total energy. Grid-scale energy-storage applications require megawatt-scale devices, which require the assembly of hundreds of large-area, bipolar cells per power plant. The cell-stack is the single system component with the largest impact on capital cost (due to the large number of highly engineered components) and operating costs (determined by overall round-trip efficiency).

  8. A novel polymer extrusion micropelletization process

    NASA Astrophysics Data System (ADS)

    Aquite, William

    Polymer micropellets provide a variety of potential applications for different processes in the polymer industry. Conventional pellets are in the size range of 2.5 mm to 5 mm, while micropellets are at least ten times smaller, in the size range of 50 μm to 1000 μm. The potential benefits to a processor using micropellets include: high surface to volume ratio, high bulk density, fast and even melting rates in extrusion, improved dry flow properties, faster injection molding cycles, and consequently lower energy consumption during processing. More specialized sintering processes that require polymer powders, such as selective sintering techniques, microporous plastics parts manufacturing, and other powder sintering methods would benefit from the production of polymer micropellets since these exhibit the advantages of pellets yet have a lower average size. This work focuses on the study of a technique developed at the Polymer Engineering Center. The technique uses a microcapillary die for the production of micropellets by causing instabilities in extruded polymer threads deformed using an air stream. Tuning of process conditions allow the development of surface disturbances that promote breakup of the threads into pellets, which are subsequently cooled and collected. Although micropellets with high sphericity and a narrow size distribution can be produced using this technique, minimal changes in process conditions also lead to the production of lenticular pellets as well as pellets, fibers and threads with a wide range of size and shape distributions. This work shows how changing processing conditions achieve a variety of shapes and sizes of micropellets, broadening its application for the production of powders from a variety of polymer resins. Different approaches were used, including dimensional analysis and numerical simulation of the micropelletization process. This research reveals the influence of non-linear viscoelastic effects on the dispersion of a polymer

  9. Polymer micromold and fabrication process

    DOEpatents

    Lee, Abraham P.; Northrup, M. Allen; Ahre, Paul E.; Dupuy, Peter C.

    1997-01-01

    A mold assembly with micro-sized features in which the hollow portion thereof is fabricated from a sacrificial mandrel which is surface treated and then coated to form an outer shell. The sacrificial mandrel is then selectively etched away leaving the outer shell as the final product. The sacrificial mandrel is fabricated by a precision lathe, for example, so that when removed by etching the inner or hollow area has diameters as small as 10's of micros (.mu.m). Varying the inside diameter contours of the mold can be accomplished with specified ramping slopes formed on the outer surface of the sacrificial mandrel, with the inside or hollow section being, for example, 275 .mu.m in length up to 150 .mu.m in diameter within a 6 mm outside diameter (o.d.) mold assembly. The mold assembly itself can serve as a micronozzle or microneedle, and plastic parts, such as microballoons for angioplasty, polymer microparts, and microactuators, etc., may be formed within the mold assembly.

  10. Polymer micromold and fabrication process

    SciTech Connect

    Lee, A.P.; Northrup, M.A.; Ahre, P.E.; Dupuy, P.C.

    1997-08-19

    A mold assembly is disclosed with micro-sized features in which the hollow portion thereof is fabricated from a sacrificial mandrel which is surface treated and then coated to form an outer shell. The sacrificial mandrel is then selectively etched away leaving the outer shell as the final product. The sacrificial mandrel is fabricated by a precision lathe, for example, so that when removed by etching the inner or hollow area has diameters as small as 10`s of micros ({micro}m). Varying the inside diameter contours of the mold can be accomplished with specified ramping slopes formed on the outer surface of the sacrificial mandrel, with the inside or hollow section being, for example, 275 {micro}m in length up to 150 {micro}m in diameter within a 6 mm outside diameter (o.d.) mold assembly. The mold assembly itself can serve as a micronozzle or microneedle, and plastic parts, such as microballoons for angioplasty, polymer microparts, and microactuators, etc., may be formed within the mold assembly. 6 figs.

  11. Interfacial Engineering for Highly Efficient-Conjugated Polymer-Based Bulk Heterojunction Photovoltaic Devices

    SciTech Connect

    Alex Jen; David Ginger; Christine Luscombe; Hong Ma

    2012-04-02

    The aim of our proposal is to apply interface engineering approach to improve charge extraction, guide active layer morphology, improve materials compatibility, and ultimately allow the fabrication of high efficiency tandem cells. Specifically, we aim at developing: i. Interfacial engineering using small molecule self-assembled monolayers ii. Nanostructure engineering in OPVs using polymer brushes iii. Development of efficient light harvesting and high mobility materials for OPVs iv. Physical characterization of the nanostructured systems using electrostatic force microscopy, and conducting atomic force microscopy v. All-solution processed organic-based tandem cells using interfacial engineering to optimize the recombination layer currents vi. Theoretical modeling of charge transport in the active semiconducting layer The material development effort is guided by advanced computer modeling and surface/ interface engineering tools to allow us to obtain better understanding of the effect of electrode modifications on OPV performance for the investigation of more elaborate device structures. The materials and devices developed within this program represent a major conceptual advancement using an integrated approach combining rational molecular design, material, interface, process, and device engineering to achieve solar cells with high efficiency, stability, and the potential to be used for large-area roll-to-roll printing. This may create significant impact in lowering manufacturing cost of polymer solar cells for promoting clean renewable energy use and preventing the side effects from using fossil fuels to impact environment.

  12. An Integrated Young Interferometer Based on UV-Imprinted Polymer Waveguides for Label-Free Biosensing Applications

    NASA Astrophysics Data System (ADS)

    Wang, M.; Hiltunen, J.; Liedert, C.; Hakalahti, L.; Myllylä, R.

    2012-06-01

    We demonstrate a polymer rib waveguide Young interferometer sensor fabricated by UV-imprinting. An inverted rib waveguide structure was utilized in order to simplify the fabrication process. In this configuration grooves are formed on the under cladding layer by UV-imprinting and core material is spin coated on top to fill the grooves. Glucose water solution was used to characterize the sensor response against ambient refractive index changes. The sensing responses correspond linearly with the refractive index change of glucose solutions with a detection limit of about 10-5. To verify the capability of the polymer sensor for biosensing, an immunoassay was performed with c-reactive protein (CRP) and human CRP specific antibody adsorbed on the waveguide surface as a receptor. The CRP solution in PBS (phosphate buffered saline) buffer with a concentration of 2 μg/ml (16 nM) resulted in an obvious response which was over a couple hundred times of the noise level. Based on these values, a detection limit of about 2.4 pg/mm^2 was found for the surface sensing of molecular adsorption. With the proposed waveguide configuration, the fabrication of polymer sensors can be ultimately transferred to roll-to-roll mass production to produce low-cost disposable sensors.

  13. Reconfigurable thermo-optic polymer switch based true-time-delay network utilizing imprinting and inkjet printing

    NASA Astrophysics Data System (ADS)

    Pan, Zeyu; Subbaraman, Harish; Zhang, Cheng; Panday, Ashwin; Li, Qiaochu; Zhang, Xingyu; Zou, Yi; Xu, Xiaochuan; Guo, L. J.; Chen, Ray T.

    2015-03-01

    Previously, we introduced a novel and an etch-free solution based procedure utilizing a combination of imprinting and inkjet printing for developing polymer photonic devices to overcome the limitations of conventional polymer photonic device fabrication techniques, such as RIE or direct pattern writing. In this work, we demonstrate the feasibility of developing very large-area photonic systems on both rigid and flexible substrates. Specifically, a complete reconfigurable 4-bit true-time-delay module, comprising of an array of five interconnected TO switches and polymer delay lines, with a dimension of 25 mm × 18 mm is developed. Because of the roll-to-roll (R2R) compatibility of the employed solution processing techniques, photonic system development over large areas at high-throughput on rigid or flexible substrates is possible, which will lead to tremendous cost savings. Moreover, these devices can be integrated with other printed photonic and electronic components, such as light sources, modulators, antennas, etc., on the same substrate, thus enabling integrated systems that can be conformably integrated on any platform.

  14. Polymer-organoclay nanocomposites by melt processing

    NASA Astrophysics Data System (ADS)

    Cui, Lili

    2009-12-01

    Polymer-layered silicate nanocomposites based on a variety of polymer matrices and several organoclays were prepared by melt processing. A detailed characterization of the thermal degradation of several commercial and experimental organoclays often used to form polymer nanocomposites was reported. The surfactant type, loading, and purification level of organoclay significantly affect their thermal stability; however, broadly speaking, the results suggest that these differences in thermal stability do not appear to have much effect on the morphology and properties of the nanocomposites formed from them. It seems that the thermal stability of organoclays is not the key factor in organoclay exfoliation in melt processed polymer nanocomposites, since the exfoliation/dispersion process may have been completed on a time scale before the degradation of surfactant progresses to a detrimental level. Polymer nanocomposites have been made from a variety of polymers; however, few matrices have demonstrated the ability to readily exfoliate the organoclay as well as nylon 6, especially for highly hydrophobic materials like polyolefins. Hence, a significant part of this research work was devoted to explore various routes to improve polyolefin-organoclay interactions, and thus, organoclay exfoliation in these systems. Amine grafted polypropylenes and a conventionally used maleic anhydride grafted polypropylene were used as compatibilizers for polypropylene based nanocomposites to improve the organoclay exfoliation. A series of ethylene vinyl acetate copolymers, the polarity of which can be adjusted by varying their vinyl acetate contents, based nanocomposites were prepared as the model system to address the relationship between the polarity of the polymers and their preferences over various organoclay structures. Attempts were made to explore the effect of degree of neutralization of acid groups in ionomers on the morphology and properties of nanocomposites, and it seems that the

  15. Automatic Processing of Reactive Polymers

    NASA Technical Reports Server (NTRS)

    Roylance, D.

    1985-01-01

    A series of process modeling computer codes were examined. The codes use finite element techniques to determine the time-dependent process parameters operative during nonisothermal reactive flows such as can occur in reaction injection molding or composites fabrication. The use of these analytical codes to perform experimental control functions is examined; since the models can determine the state of all variables everywhere in the system, they can be used in a manner similar to currently available experimental probes. A small but well instrumented reaction vessel in which fiber-reinforced plaques are cured using computer control and data acquisition was used. The finite element codes were also extended to treat this particular process.

  16. Investigation of the interfacial adhesion of the transparent conductive oxide films to large-area flexible polymer substrates using laser-induced thermo-mechanical stresses

    NASA Astrophysics Data System (ADS)

    Park, Jin-Woo; Lee, Seung-Ho; Yang, Chan-Woo

    2013-08-01

    In this study, we investigated the interfacial adhesion strength (σint) of transparent conductive oxide (TCO) coatings on polymer substrates using a nanosecond Nd:YAG pulsed laser. We compared our results with those achieved using conventional testing methods such as bending and fragmentation tests as well as theoretical calculations. In the fragmentation and bending tests, mechanical compressive stress is induced in the film due to mismatches in Poisson's ratio and Young's modulus between the substrate and film. But, the incident laser makes the film under compression due to the mismatch in thermal expansion between the TCO and the polymer substrate. With a pulse incident to the substrate, the TCO rapidly expands by laser-induced instant heating while the transparent polymer does little, which causes the TCO to buckle and delaminate over the critical pulse energy. The critical compressive stress that scales with σint was calculated using simple equations, which agreed well with the results from previous theoretical calculations. Because the films preferentially delaminate at the defects and grain boundaries, this technique also provided useful information regarding the interface microstructures. Moreover, because the laser can scan over large areas, this method is suitable for flexible substrates that are produced by a roll-to-roll process. Nevertheless, the mechanical stress introduced by the bending and fragmentation tests causes the TCO to buckle without interfacial delamination. Hence, the stresses at the buckling disagreed with the results obtained from the laser test and the theoretical calculations.

  17. Polymer waveguide technology for flexible display applications

    NASA Astrophysics Data System (ADS)

    Okuda, Yuuto; Fujieda, Ichiro

    2012-03-01

    We consider applications of wave-guiding technologies for flexible displays. First, a flexible backlight can be constructed by guiding laser light through an optical fiber arranged in a spiral manner. The light leaks out via the grooves fabricated on the optical fiber. For uniform illumination, the probability of light extraction at each groove and the pitch of the grooves are adjusted. Second, a polymer waveguide with successive branches distributes the optical power from a laser to two-dimensional emission points on a plane. The division ratio at each branch is an important design parameter for uniform light output. At each branch and emission point, a mirror is placed for 90-degree optical path redirection. This constitutes a flexible backlight. Third, in a more technically demanding design, a mirror based on the micro-electro-mechanical systems technology scans a laser beam on the entrance surface of the waveguide and each emission point is addressed sequentially. An image can be displayed by intensity modulation of the laser light synchronized to this scanning action. The precision of the waveguide fabrication and the beam scanning accuracy would determine the display resolution. Finally, such a waveguide may be applied for concentrated photovoltaic applications. An array of lenses is stacked on the waveguide so that the optical power is focused on each mirror. The direction of the light propagation is reversed. Now the exit surface of the waveguide is coupled to solar cells. In all these cases, the polymer waveguide technology offers a cost advantage due to its feasibility for the roll-to-roll process.

  18. Grid-connected polymer solar panels: initial considerations of cost, lifetime, and practicality.

    PubMed

    Medford, Andrew J; Lilliedal, Mathilde R; Jørgensen, Mikkel; Aarø, Dennis; Pakalski, Heinz; Fyenbo, Jan; Krebs, Frederik C

    2010-09-13

    Large solar panels were constructed from polymer solar cell modules prepared using full roll-to-roll (R2R) manufacture based on the previously published ProcessOne. The individual flexible polymer solar modules comprising multiple serially connected single cell stripes were joined electrically and laminated between a 4 mm tempered glass window and black Tetlar foil using two sheets of 0.5 mm thick ethylene vinyl acetate (EVA). The panels produced up to 8 W with solar irradiance of ~960 Wm⁻², and had outer dimensions of 1 m x 1.7 m with active areas up to 9180 cm². Panels were mounted on a tracking station and their output was grid connected between testing. Several generations of polymer solar cells and panel constructions were tested in this context to optimize the production of polymer solar panels. Cells lacking a R2R barrier layer were found to degrade due to diffusion of oxygen after less than a month, while R2R encapsulated cells showed around 50% degradation after 6 months but suffered from poor performance due to de-lamination during panel production. A third generation of panels with various barrier layers was produced to optimize the choice of barrier foil and it was found that the inclusion of a thin protective foil between the cell and the barrier foil is critical. The findings provide a preliminary foundation for the production and optimization of large-area polymer solar panels and also enabled a cost analysis of solar panels based on polymer solar cells.

  19. Grid-connected polymer solar panels: initial considerations of cost, lifetime, and practicality.

    PubMed

    Medford, Andrew J; Lilliedal, Mathilde R; Jørgensen, Mikkel; Aarø, Dennis; Pakalski, Heinz; Fyenbo, Jan; Krebs, Frederik C

    2010-09-13

    Large solar panels were constructed from polymer solar cell modules prepared using full roll-to-roll (R2R) manufacture based on the previously published ProcessOne. The individual flexible polymer solar modules comprising multiple serially connected single cell stripes were joined electrically and laminated between a 4 mm tempered glass window and black Tetlar foil using two sheets of 0.5 mm thick ethylene vinyl acetate (EVA). The panels produced up to 8 W with solar irradiance of ~960 Wm⁻², and had outer dimensions of 1 m x 1.7 m with active areas up to 9180 cm². Panels were mounted on a tracking station and their output was grid connected between testing. Several generations of polymer solar cells and panel constructions were tested in this context to optimize the production of polymer solar panels. Cells lacking a R2R barrier layer were found to degrade due to diffusion of oxygen after less than a month, while R2R encapsulated cells showed around 50% degradation after 6 months but suffered from poor performance due to de-lamination during panel production. A third generation of panels with various barrier layers was produced to optimize the choice of barrier foil and it was found that the inclusion of a thin protective foil between the cell and the barrier foil is critical. The findings provide a preliminary foundation for the production and optimization of large-area polymer solar panels and also enabled a cost analysis of solar panels based on polymer solar cells. PMID:21165057

  20. Efficient organic solar cells processed from hydrocarbon solvents

    NASA Astrophysics Data System (ADS)

    Zhao, Jingbo; Li, Yunke; Yang, Guofang; Jiang, Kui; Lin, Haoran; Ade, Harald; Ma, Wei; Yan, He

    2016-02-01

    Organic solar cells have desirable properties, including low cost of materials, high-throughput roll-to-roll production, mechanical flexibility and light weight. However, all top-performance devices are at present processed using halogenated solvents, which are environmentally hazardous and would thus require expensive mitigation to contain the hazards. Attempts to process organic solar cells from non-halogenated solvents lead to inferior performance. Overcoming this hurdle, here we present a hydrocarbon-based processing system that is not only more environmentally friendly but also yields cells with power conversion efficiencies of up to 11.7%. Our processing system incorporates the synergistic effects of a hydrocarbon solvent, a novel additive, a suitable choice of polymer side chain, and strong temperature-dependent aggregation of the donor polymer. Our results not only demonstrate a method of producing active layers of organic solar cells in an environmentally friendly way, but also provide important scientific insights that will facilitate further improvement of the morphology and performance of organic solar cells.

  1. Processing of polymers in high magnetic fields

    SciTech Connect

    Douglas, E.P.; Smith, M.E.; Benicewicz, B.C.; Earls, J.D.; Priester, R.D. Jr.

    1996-05-01

    Many organic molecules and polymers have an anisotropic diamagnetic susceptibility, and thus can be aligned in high magnetic fields. The presence of liquid crystallinity allows cooperative motions of the individual molecules, and thus the magnetic energy becomes greater than the thermal energy at experimentally obtainable field strengths. This work has determined the effect of magnetic field alignment on the thermal expansion and mechanical properties of liquid crystalline thermosets in the laboratory. Further advances in magnet design are needed to make magnetic field alignment a commercially viable approach to polymer processing. The liquid crystal thermoset chosen for this study is the diglycidyl ether of dihydroxy-{alpha}-methylstilbene cured with the diamine sulfamilamide. This thermoset has been cured at field strengths up to 18 Tesla.

  2. Magnetic field processing of inorganic polymers

    SciTech Connect

    Kunerth, D.C.; Peterson, E.S.

    1995-05-01

    The purpose of this project is to investigate, understand, and demonstrate the use of magnetic field processing (MFP) to modify the properties of inorganic-based polymers and to develop the basic technical knowledge required for industrial implementation. Polyphosphazene membranes for chemical separation applications are being emphasized by this project. Previous work demonstrated that magnetic fields, appropriately applied during processing, can be used to beneficially modify membrane morphology. MFP membranes have significantly increased flux capabilities while maintaining the same chemical selectivity as the unprocessed membranes.

  3. Asymmetric Mach-Zehnder interferometers without an interaction window in polymer foils for refractive index sensing.

    PubMed

    Hofmann, Meike; Xiao, Yanfen; Sherman, Stanislav; Gleissner, Uwe; Schmidt, Thomas; Zappe, Hans

    2016-02-10

    We report on the fabrication and characterization of integrated Mach-Zehnder interferometers in polymer foil without an interaction window. The interferometers are based on inverted rib waveguides, which allow single mode behavior even for waveguide widths larger than a few micrometers. The phase change between the two interferometer arms upon a refractive index change of the analyte that serves as the upper cladding is generated by the asymmetricity of the two interferometer arms. A difference of the waveguide width in the straight part of the interferometer leads to different effective refractive indices and thus to a change in the interference signal. We show in small scale the process chain, which is compatible with a cost-effective roll-to-roll fabrication process. For a proof of principle we apply deionized water and a glucose solution as analytes to the sensor foils and detect the transmitted intensity as a measure of the induced phase change. A detection limit of 3·10⁻³ refractive index units is reached for homogeneous sensing at a total system length of 9.3 mm and a total waveguide core thickness of 3 μm.

  4. Stability Comparison of Perovskite Solar Cells Based on Zinc Oxide and Titania on Polymer Substrates.

    PubMed

    Dkhissi, Yasmina; Meyer, Steffen; Chen, Dehong; Weerasinghe, Hasitha C; Spiccia, Leone; Cheng, Yi-Bing; Caruso, Rachel A

    2016-04-01

    Device scale-up and long-term stability constitute two major hurdles that the emerging perovskite solar technology will have to overcome before commercialization. Here, a comparative study was performed between ZnO and TiO2 electron-selective layers, two materials that allow the low-temperature processing of perovskite solar cells on polymer substrates. Although the use of TiO2 is well established on glass substrates, ZnO was chosen because it can be readily printed at low temperature and offers the potential for the large-scale roll-to-roll manufacturing of flexible photovoltaics at a low cost. However, a rapid degradation of CH3 NH3 PbI3 was observed if it was deposited on ZnO, therefore, the influence of the perovskite film preparation conditions on its morphology and degradation kinetics was investigated. This study showed that CH3 NH3 PbI3 could withstand a higher temperature on TiO2 than ZnO and that TiO2-based perovskite devices were more stable than their ZnO analogues. PMID:26893225

  5. Process to produce lithium-polymer batteries

    DOEpatents

    MacFadden, Kenneth Orville

    1998-01-01

    A polymer bonded sheet product suitable for use as an electrode in a non-aqueous battery system. A porous electrode sheet is impregnated with a solid polymer electrolyte, so as to diffuse into the pores of the electrode. The composite is allowed to cool, and the electrolyte is entrapped in the porous electrode. The sheet products composed have the solid polymer electrolyte composition diffused into the active electrode material by melt-application of the solid polymer electrolyte composition into the porous electrode material sheet. The solid polymer electrolyte is maintained at a temperature that allows for rapid diffusion into the pores of the electrode. The composite electrolyte-electrode sheets are formed on current collectors and can be coated with solid polymer electrolyte prior to battery assembly. The interface between the solid polymer electrolyte composite electrodes and the solid polymer electrolyte coating has low resistance.

  6. Process to produce lithium-polymer batteries

    DOEpatents

    MacFadden, K.O.

    1998-06-30

    A polymer bonded sheet product is described suitable for use as an electrode in a non-aqueous battery system. A porous electrode sheet is impregnated with a solid polymer electrolyte, so as to diffuse into the pores of the electrode. The composite is allowed to cool, and the electrolyte is entrapped in the porous electrode. The sheet products composed have the solid polymer electrolyte composition diffused into the active electrode material by melt-application of the solid polymer electrolyte composition into the porous electrode material sheet. The solid polymer electrolyte is maintained at a temperature that allows for rapid diffusion into the pores of the electrode. The composite electrolyte-electrode sheets are formed on current collectors and can be coated with solid polymer electrolyte prior to battery assembly. The interface between the solid polymer electrolyte composite electrodes and the solid polymer electrolyte coating has low resistance. 1 fig.

  7. Process for hardening the surface of polymers

    DOEpatents

    Mansur, L.K.; Lee, E.H.

    1992-07-14

    Hard surfaced polymers and the method for making them is generally described. Polymers are subjected to simultaneous multiple ion beam bombardment, that results in a hardening of the surface and improved wear resistance. 1 figure.

  8. Process for hardening the surface of polymers

    DOEpatents

    Mansur, Louis K.; Lee, Eal H.

    1992-01-01

    Hard surfaced polymers and the method for making them is generally described. Polymers are subjected to simultaneous multiple ion beam bombardment, that results in a hardening of the surface and improved wear resistance.

  9. Rheometry of polymer melts using processing machines

    NASA Astrophysics Data System (ADS)

    Friesenbichler, Walter; Neunhäuserer, Andreas; Duretek, Ivica

    2016-08-01

    The technology of slit-die rheometry came into practice in the early 1960s. This technique enables engineers to measure the pressure drop very precisely along the slit die. Furthermore, slit-die rheometry widens up the measurable shear rate range and it is possible to characterize rheological properties of complicated materials such as wall slipping PVCs and high-filled compounds like long fiber reinforced thermoplastics and PIM-Feedstocks. With the use of slit-die systems in polymer processing machines e.g., Rauwendaal extrusion rheometer, by-pass extrusion rheometer, injection molding machine rheometers, new possibilities regarding rheological characterization of thermoplastics and elastomers at processing conditions near to practice opened up. Special slit-die systems allow the examination of the pressure-dependent viscosity and the characterization of cross-linking elastomers because of melt preparation and reachable shear rates comparable to typical processing conditions. As a result of the viscous dissipation in shear and elongational flows, when performing rheological measurements for high-viscous elastomers, temperature-correction of the apparent values has to be made. This technique was refined over the last years at Montanuniversitaet. Nowadays it is possible to characterize all sorts of rheological complicated polymeric materials under process- relevant conditions with viscosity values fully temperature corrected.

  10. Laser Processing of Metals and Polymers

    SciTech Connect

    Singaravelu, Senthilraja

    2012-05-01

    A laser offers a unique set of opportunities for precise delivery of high quality coherent energy. This energy can be tailored to alter the properties of material allowing a very flexible adjustment of the interaction that can lead to melting, vaporization, or just surface modification. Nowadays laser systems can be found in nearly all branches of research and industry for numerous applications. Sufficient evidence exists in the literature to suggest that further advancements in the field of laser material processing will rely significantly on the development of new process schemes. As a result they can be applied in various applications starting from fundamental research on systems, materials and processes performed on a scientific and technical basis for the industrial needs. The interaction of intense laser radiation with solid surfaces has extensively been studied for many years, in part, for development of possible applications. In this thesis, I present several applications of laser processing of metals and polymers including polishing niobium surface, producing a superconducting phase niobium nitride and depositing thin films of niobium nitride and organic material (cyclic olefin copolymer). The treated materials were examined by scanning electron microscopy (SEM), electron probe microanalysis (EPMA), atomic force microscopy (AFM), high resolution optical microscopy, surface profilometry, Fourier transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD). Power spectral density (PSD) spectra computed from AFM data gives further insight into the effect of laser melting on the topography of the treated niobium.

  11. Vacuum ultraviolet photo-physical chemistry of hydrocarbon polymers

    NASA Astrophysics Data System (ADS)

    Truica-Marasescu, Florina-Elena

    The purpose of this study has been to investigate fundamental processes involved in the vacuum ultraviolet (VUV, lambda < 200 nm)-induced modification of polymer surfaces and their physico-chemical properties. It is well known that VUV photons provide an important photochemical contribution during plasma treatments of polymers, for example: ablation of material; crosslinking and chemical modification of the near-surface region can also be performed by VUV irradiation. During the last 30 years, VUV treatments have received increasing attention, due to a few key advantages over their plasma counterparts. These include the possibility of treating commercial polymer films at atmospheric pressure, thereby alleviating the need for expensive vacuum pumps and other auxiliary equipment necessary for continuous low-pressure plasma roll-to-roll treatment of flexible substrates. Another important advantage of VUV photochemistry over plasma is that more specific surface chemistries can be achieved with monochromatic VUV radiation, due to selective (photo-) chemistries both on the solid surface and in the gas phase. The hydrocarbon polymers used for this study were well-characterized low-density polyethylene, LDPE; biaxially-oriented polypropylene, BOPP; polystyrene, PS; and poly(methylmethacrylate), PMMA. Due to the complexity of interactions between VUV photons and polymers, especially when the latter are in a reactive gas, VUV-wavelength-dependent effects on the physico-chemical properties of irradiated polymer surfaces have been investigated under two different set of conditions, namely: VUV exposure in vacuum, and in a reactive atmosphere of low-pressure ammonia, VUV/NH3. In the former case, we investigated wavelength (lambda)-dependent material ablation ("etching") by in-situ quartz crystal microbalance (QCM) measurements, as a function of the irradiation dose, D. Near-surface structural changes (the creation of unsaturation, cross-linking, etc.) and radical

  12. Forming of polymer nanofibers by a pressurised gyration process.

    PubMed

    Mahalingam, Suntharavathanan; Edirisinghe, Mohan

    2013-07-25

    A new route consisting of simultaneous centrifugal spinning and solution blowing to form polymer nanofibers is reported. The fiber diameter (60-1000 nm) is shown to be a function of polymer concentration, rotational speed, and working pressure of the processing system. The fiber length is dependent on the rotational speed. The process can deliver 6 kg of fiber per hour and therefore offers mass production capabilities compared with other established polymer nanofiber generation methods such as electrospinning, centrifugal spinning, and blowing.

  13. Effect of processing on Polymer/Composite structure and properties

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Advances in the vitality and economic health of the field of polymer forecasting are discussed. A consistent and rational point of view which considers processing as a participant in the underlying triad of relationships which comprise materials science and engineering is outlined. This triad includes processing as it influences material structure, and ultimately properties. Methods in processing structure properties, polymer science and engineering, polymer chemistry and synthesis, structure and modification and optimization through processing, and methods of melt flow modeling in processing structure property relations of polymer were developed. Mechanical properties of composites are considered, and biomedical materials research to include polymer processing effects are studied. An analysis of the design technology of advances graphite/epoxy composites is also reported.

  14. Experiments towards establishing of design rules for R2R-UV-NIL with polymer working shims

    NASA Astrophysics Data System (ADS)

    Nees, Dieter; Ruttloff, Stephan; Palfinger, Ursula; Stadlober, Barbara

    2016-03-01

    Roll-to-Roll-UV-nanoimprint lithography (R2R-UV-NIL) enables high resolution large area patterning of flexible substrates and is therefore of increasing industrial interest. We have set up a custom-made R2R-UV-NIL pilot machine which is able to convert 10 inch wide web with velocities of up to 30 m/min. In addition, we have developed self-replicable UV-curable resins with tunable surface energy and Young's modulus for UV-imprint material as well as for polymer working stamp/shim manufacturing. Now we have designed test patterns for the evaluation of the impact of structure shape, critical dimension, pitch, depth, side wall angle and orientation relative to the web movement onto the imprint fidelity and working shim life time. We have used female (recessed structures) silicon masters of that design with critical dimensions between CD = 200 nm and 1600 nm, and structure depths of d = 500 nm and 1000 nm - all with vertical as well as inclined side walls. These entire master patterns have been transferred onto single male (protruding structures) R2R polymer working shims. The polymer working shims have been used for R2R-UV-NIL runs of several hundred meters and the imprint fidelity and process stability of the various test patterns have been compared. This study is intended as a first step towards establishing of design rules and developing of nanoimprint proximity correction strategies for industrial R2R-UV-NIL processes using polymer working shims.

  15. Stability analysis of a polymer coating process

    NASA Astrophysics Data System (ADS)

    Kallel, A.; Hachem, E.; Demay, Y.; Agassant, J. F.

    2015-05-01

    A new coating process involving a short stretching distance (1 mm) and a high draw ratio (around 200) is considered. The resulting thin molten polymer film (around 10 micrometers) is set down on a solid primary film and then covered by another solid secondary film. In experimental studies, periodical fluctuation in the thickness of the coated layer may be observed. The processing conditions markedly influence the onset and the development of these defects and modeling will help our understanding of their origins. The membrane approach which has been commonly used for cast film modeling is no longer valid and two dimensional time dependent models (within the thickness) are developed in the whole domain (upstream die and stretching path). A boundary-value problem with a free surface for the Stokes equations is considered and stability of the free surface is assessed using two different numerical strategies: a tracking strategy combined with linear stability analysis involving computation of leading eigenvalues, and a Level Set capturing strategy coupled with transient stability analysis.

  16. Process for crosslinking and extending conjugated diene-containing polymers

    NASA Technical Reports Server (NTRS)

    Bell, Vernon L. (Inventor); Havens, Stephen J. (Inventor)

    1977-01-01

    A process using a Diels-Alder reaction which increases the molecular weight and/or crosslinks polymers by reacting the polymers with bisunsaturated dienophiles is developed. The polymer comprises at least 75% by weight based on the reaction product, has a molecular weight of at least 5000 and a plurality of conjugated 1,3-diene systems incorporated into the molecular structure. A dienophile reaction with the conjugated 1,3-diene of the polymer is at least 1% by weight based on the reaction product. Examples of the polymer include polyesters, polyamides, polyethers, polysulfones and copolymers. The bisunsaturated dienophiles may include bis-maleimides, bis maleic and bis tumaric esters and amides. This method for expanding the molecular weight chains of the polymers, preferable thermoplastics, is advantageous for processing or fabricating thermoplastics. A low molecular weight thermoplastic is converted to a high molecular weight plastic having improved strength and toughness for use in the completed end use article.

  17. Stochastic resonance during a polymer translocation process

    NASA Astrophysics Data System (ADS)

    Mondal, Debasish; Muthukumar, M.

    2016-04-01

    We have studied the occurrence of stochastic resonance when a flexible polymer chain undergoes a single-file translocation through a nano-pore separating two spherical cavities, under a time-periodic external driving force. The translocation of the chain is controlled by a free energy barrier determined by chain length, pore length, pore-polymer interaction, and confinement inside the donor and receiver cavities. The external driving force is characterized by a frequency and amplitude. By combining the Fokker-Planck formalism for polymer translocation and a two-state model for stochastic resonance, we have derived analytical formulas for criteria for emergence of stochastic resonance during polymer translocation. We show that no stochastic resonance is possible if the free energy barrier for polymer translocation is purely entropic in nature. The polymer chain exhibits stochastic resonance only in the presence of an energy threshold in terms of polymer-pore interactions. Once stochastic resonance is feasible, the chain entropy controls the optimal synchronization conditions significantly.

  18. A Graduate Course in Polymer Processing.

    ERIC Educational Resources Information Center

    Middleman, Stanley

    1978-01-01

    This course, offered by the departments of chemical engineering and polymer science and engineering at the University of Massachusetts, is mainly a course in applied fluid dynamics with an emphasis on flow pressures dominated by viscous effects. (BB)

  19. Continuous process to produce lithium-polymer batteries

    DOEpatents

    Chern, Terry Song-Hsing; Keller, David Gerard; MacFadden, Kenneth Orville

    1998-01-01

    Solid polymer electrolytes are extruded with active electrode material in a continuous, one-step process to form composite electrolyte-electrodes ready for assembly into battery cells. The composite electrolyte-electrode sheets are extruded onto current collectors to form electrodes. The composite electrodes, as extruded, are electronically and ionically conductive. The composite electrodes can be overcoated with a solid polymer electrolyte, which acts as a separator upon battery assembly. The interface between the solid polymer electrolyte composite electrodes and the solid polymer electrolyte separator has low resistance.

  20. Continuous process to produce lithium-polymer batteries

    DOEpatents

    Chern, T.S.H.; Keller, D.G.; MacFadden, K.O.

    1998-05-12

    Solid polymer electrolytes are extruded with active electrode material in a continuous, one-step process to form composite electrolyte-electrodes ready for assembly into battery cells. The composite electrolyte electrode sheets are extruded onto current collectors to form electrodes. The composite electrodes, as extruded, are electronically and ionically conductive. The composite electrodes can be over coated with a solid polymer electrolyte, which acts as a separator upon battery assembly. The interface between the solid polymer electrolyte composite electrodes and the solid polymer electrolyte separator has low resistance. 1 fig.

  1. Solid electrolyte material manufacturable by polymer processing methods

    DOEpatents

    Singh, Mohit; Gur, Ilan; Eitouni, Hany Basam; Balsara, Nitash Pervez

    2012-09-18

    The present invention relates generally to electrolyte materials. According to an embodiment, the present invention provides for a solid polymer electrolyte material that is ionically conductive, mechanically robust, and can be formed into desirable shapes using conventional polymer processing methods. An exemplary polymer electrolyte material has an elastic modulus in excess of 1.times.10.sup.6 Pa at 90 degrees C. and is characterized by an ionic conductivity of at least 1.times.10.sup.-5 Scm-1 at 90 degrees C. An exemplary material can be characterized by a two domain or three domain material system. An exemplary material can include material components made of diblock polymers or triblock polymers. Many uses are contemplated for the solid polymer electrolyte materials. For example, the present invention can be applied to improve Li-based batteries by means of enabling higher energy density, better thermal and environmental stability, lower rates of self-discharge, enhanced safety, lower manufacturing costs, and novel form factors.

  2. Growing perovskite into polymers for easy-processable optoelectronic devices.

    PubMed

    Masi, Sofia; Colella, Silvia; Listorti, Andrea; Roiati, Vittoria; Liscio, Andrea; Palermo, Vincenzo; Rizzo, Aurora; Gigli, Giuseppe

    2015-01-12

    Here we conceive an innovative nanocomposite to endow hybrid perovskites with the easy processability of polymers, providing a tool to control film quality and material crystallinity. We verify that the employed semiconducting polymer, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), controls the self-assembly of CH₃NH₃PbI₃ (MAPbI₃) crystalline domains and favors the deposition of a very smooth and homogenous layer in one straightforward step. This idea offers a new paradigm for the implementation of polymer/perovskite nanocomposites towards versatile optoelectronic devices combined with the feasibility of mass production. As a proof-of-concept we propose the application of such nanocomposite in polymer solar cell architecture, demonstrating a power conversion efficiency up to 3%, to date the highest reported for MEH-PPV. On-purpose designed polymers are expected to suit the nanocomposite properties for the integration in diverse optoelectronic devices via facile processing condition.

  3. Growing perovskite into polymers for easy-processable optoelectronic devices.

    PubMed

    Masi, Sofia; Colella, Silvia; Listorti, Andrea; Roiati, Vittoria; Liscio, Andrea; Palermo, Vincenzo; Rizzo, Aurora; Gigli, Giuseppe

    2015-01-01

    Here we conceive an innovative nanocomposite to endow hybrid perovskites with the easy processability of polymers, providing a tool to control film quality and material crystallinity. We verify that the employed semiconducting polymer, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), controls the self-assembly of CH₃NH₃PbI₃ (MAPbI₃) crystalline domains and favors the deposition of a very smooth and homogenous layer in one straightforward step. This idea offers a new paradigm for the implementation of polymer/perovskite nanocomposites towards versatile optoelectronic devices combined with the feasibility of mass production. As a proof-of-concept we propose the application of such nanocomposite in polymer solar cell architecture, demonstrating a power conversion efficiency up to 3%, to date the highest reported for MEH-PPV. On-purpose designed polymers are expected to suit the nanocomposite properties for the integration in diverse optoelectronic devices via facile processing condition. PMID:25579988

  4. Electric Field-Mediated Processing of Polymers. Appendix 1

    NASA Technical Reports Server (NTRS)

    Wnek, G. E.; Bowlin, G. L.; Haas, T. W.

    2000-01-01

    Significant opportunities exist for the processing of polymers (homopolymers and blends) using electric fields. We suggest that a broad range of properties can be achieved using a relatively small number of polymers, with electric fields providing the ability to tailor properties via the control of shape, morphology, and orientation. Specific attention is given to electrospinning, but we note that electroaerosol formation and field-modulated film casting represent additional processing options.

  5. Processing and post-processing issues related to polymer films

    NASA Astrophysics Data System (ADS)

    Mueller, Chad David

    1998-12-01

    In Chapter 1, the effect of heat sealing variables on seal strength of a linear low density polyethylene (LLDPE) was examined. Blown films were heat sealed for various times and temperatures so that the films ranged from partially to fully melted. A temperature of 115sp°C or higher was required to form a good seal and was related to the heterogeneous composition of the LLDPE studied. At 115sp°C, the lower molecular weight, more highly branched chains easily diffused across the interface. However, because these chains represented a small fraction of the crystallinity and the molecular weight was low, they contributed much less than the full peel strength. Conversely, chains with less branching represented the main fraction of crystallinity (anchors for tie chains) and the highest molecular weights (more entanglements). Only at temperatures where the higher molecular weight, less branched chains began to melt and diffuse across the interface could high peel strengths be achieved. In Chapter 2, a novel coextrusion process used to create microlayered hierarchically structured films is described. With this technology, two or three polymers can be multiplied into tens or thousands of alternating layers. This unique coextrusion process can be used to combine polymers of widely dissimilar solid state morphologies and properties into unique layered and gradient structures. In addition, the effect of the viscosity ratio of the component materials and the effect of the layer multiplier geometry on the layer structure and uniformity was investigated. In Chapter 3, the development of a breathable film produced by the microlayer process is described. Two systems were produced: one with poly(ethylene oxide) (PEO) and CaCOsb3-filled LLDPE and the other with PEO and CaCOsb3-filled polypropylene. The water vapor transport (WVT) behavior of these films was measured and related to the tortuousity of the path through the PEO and filled polyolefin domains. PEO is water soluble and has

  6. Metal particle compaction during drop-substrate impact for inkjet printing and drop-casting processes

    NASA Astrophysics Data System (ADS)

    Clancy, I.; Amarandei, G.; Nash, C.; Glowacki, B. A.

    2016-02-01

    Direct coating methods using metal particles from aqueous solutions or solvent-based inks become central in the roll-to-roll fabrication processes as these methods can lead to continuous or pre-defined conductive layers on a large variety of substrates. For good electrical conductivity, the metal particles have to be brought into contact, and traditionally, additional sintering treatments are required. Such treatments can degrade the sensitive substrates as paper or polymer films. In this study, the possibility of obtaining conductive layers at room temperature is investigated for direct coating methods with an emphasis on drop-casting and inkjet printing. Thus, it is shown that electrical conductive layers can be achieved if the metal particles can compact during the drop-substrate impact interaction. It is theoretically shown that the compaction process is directly related to the particle and ink drop size, the initial fractional particle loading of the ink, solvent viscosity, and drop velocity. The theoretical predictions on compaction are experimentally validated, and the particle compaction's influence on changes in the electrical conductivity of the resulting layers is demonstrated.

  7. Use of molecularly imprinted polymers in a biotransformation process.

    PubMed

    Ye, L; Ramström, O; Ansell, R J; Månsson, M O; Mosbach, K

    1999-09-20

    Molecularly imprinted polymers are highly stable and can be sterilised, making them ideal for use in biotransformation process. In this communication, we describe a novel application of molecularly imprinted polymers in an enzymatic reaction. The enzymatic condensation of Z-L-aspartic acid with L-phenylalanine methyl ester to give Z-L-Asp-L-Phe-OMe (Z-aspartame) was chosen as a model system to evaluate the applicability of using molecularly imprinted polymers to facilitate product formation. When the product-imprinted polymer is present, a considerable increase (40%) in product yield is obtained. Besides their use to enhance product yields, as demonstrated here, we suggest that imprinted polymers may also find use in the continuous removal of toxic compounds during biochemical reactions.

  8. Novel carbon nanotube-conjugated polymer nanohybrids produced by multiple polymer processing.

    PubMed

    Stranks, Samuel D; Habisreutinger, Severin N; Dirks, Beate; Nicholas, Robin J

    2013-08-21

    We describe two methods in which we manipulate the binding of multiple conjugated polymers to single-walled carbon nanotubes (SWNTs) to produce new and novel nanostructures. One method fi rst utilizes the selective binding of poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO) to a narrow distribution of semiconducting SWNTs and then uses a polymer exchange to transfer this purity to other nanotube-polymer combinations, using technologically useful polymers such as poly(3-hexylthiophene) (P3HT) and poly(9,9'-dioctylfluoreneco -benzothiadiazole) (F8BT) as fi rst examples. The other method involves controlling the competitive binding of P3HT and F8BT to SWNTs to produce coaxial nanostructures consisting of both polymers simultaneously bound in ordered layers. We show that these two simple solution-processing techniques can be carried out sequentially to afford new dual-polymer nanostructures comprised of a semiconducting SWNT of a single chirality. This allows the favorable properties of both polymers and purified semiconducting SWNTs to be implemented into potentially highly efficient organic photovoltaic devices. PMID:24137628

  9. Composites processed from wood fibers and automobile polymer fluff

    NASA Astrophysics Data System (ADS)

    Shi, Qiang

    The objective of this research effort was to investigate the physical and mechanical properties of composites processed from wood fiber and automobile polymer fluff. To this end, a study was conducted to investigate the feasibility of incorporating polymer fluff in dry-process wood fiberboard using polymeric diphenylmethane diisocyanate and phenol - formaldehyde resins. The effect of polymer fluff content and polymer fluff particle size on the physical and mechanical properties of wood fiber/fluff composites was also investigated. The surface properties (dispersive energy and acid-base properties) of the polymer fluff materials and the thermal mechanically pulped hardwood fibers were characterized using contact angle analysis and inverse gas chromatography. Detailed studies were conducted on the moisture related properties of the wood fiber/fluff composites such as moisture transfer and thickness swelling, using both a water immersion test and moisture vapor test. A model to predict the maximum water absorption of water immersion was established for wood fiber/fluff composites as a function of board density and polymer fluff content. A swelling model was also established to predict the hygroscopic thickness swelling rate of composites in a water vapor environment. A moisture diffusion model based on Fick's second law of diffusion was applied to the moisture absorption process of the composites from which the diffusion coefficients and surface emission coefficients were calculated using a nonlinear curve fitting algorithm. The experimental results indicated that automobile polymer fluff, after processing through several simple procedures including separation, cleansing, and granulation, could be recycled by manufacturing dry-process wood fiber/fluff composites. The smaller the polymer fluff particle size, the higher the internal bond, and the lower the thickness swelling and water absorption. Polymer fluff size did not have a significant effect on the bending

  10. Slow process in confined polymer melts: Layer exchange dynamics at a polymer solid interface

    NASA Astrophysics Data System (ADS)

    Yelash, L.; Virnau, P.; Binder, K.; Paul, W.

    2010-11-01

    Employing Molecular Dynamics simulations of a chemically realistic model of 1,4-polybutadiene between graphite walls we show that the mass exchange between layers close to the walls is a slow process already in the melt state. For the glass transition of confined polymers this process competes with the slowing down due to packing effects and intramolecular rotation barriers.

  11. Collaborative Investigations of Supramolecular Polymer Assembly Processes.

    NASA Astrophysics Data System (ADS)

    Wooley, Karen

    2007-03-01

    It is a pleasure to participate in this symposium, honoring Darrin J. Pochan's awarding of the John H. Dillon Medal for advancing our understanding of the physics of assembly and chain conformation of synthetic polypeptides. Assemblies of polypeptides, polysaccharides and polymers of nucleic acids are, of course, complex natural systems that form the bases of life. Over the past three years, we have worked together as a highly interdisciplinary team of investigators, to investigate the self assembly behaviors and resulting morphologies for synthetic amphiphilic block copolymer systems. This presentation will highlight the findings from these collaborative studies, including the importance of the block copolymer composition and topology and the significance of the assembly conditions.

  12. Azobenzene-based supramolecular polymers for processing MWCNTs

    NASA Astrophysics Data System (ADS)

    Maggini, Laura; Marangoni, Tomas; Georges, Benoit; Malicka, Joanna M.; Yoosaf, K.; Minoia, Andrea; Lazzaroni, Roberto; Armaroli, Nicola; Bonifazi, Davide

    2012-12-01

    Photothermally responsive supramolecular polymers containing azobenzene units have been synthesised and employed as dispersants for multi-walled carbon nanotubes (MWCNTs) in organic solvents. Upon triggering the trans-cis isomerisation of the supramolecular polymer intermolecular interactions between MWCNTs and the polymer are established, reversibly affecting the suspensions of the MWCNTs, either favouring it (by heating, i.e. cis --> trans isomerisation) or inducing the CNTs' precipitation (upon irradiation, trans --> cis isomerisation). Taking advantage of the chromophoric properties of the molecular subunits, the solubilisation/precipitation processes have been monitored by UV-Vis absorption spectroscopy. The structural properties of the resulting MWCNT-polymer hybrid materials have been thoroughly investigated via thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and atomic force microscopy (AFM) and modelled with molecular dynamics simulations.Photothermally responsive supramolecular polymers containing azobenzene units have been synthesised and employed as dispersants for multi-walled carbon nanotubes (MWCNTs) in organic solvents. Upon triggering the trans-cis isomerisation of the supramolecular polymer intermolecular interactions between MWCNTs and the polymer are established, reversibly affecting the suspensions of the MWCNTs, either favouring it (by heating, i.e. cis --> trans isomerisation) or inducing the CNTs' precipitation (upon irradiation, trans --> cis isomerisation). Taking advantage of the chromophoric properties of the molecular subunits, the solubilisation/precipitation processes have been monitored by UV-Vis absorption spectroscopy. The structural properties of the resulting MWCNT-polymer hybrid materials have been thoroughly investigated via thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and atomic force microscopy

  13. Heterogeneity in polymer solar cells: local morphology and performance in organic photovoltaics studied with scanning probe microscopy.

    PubMed

    Groves, Chris; Reid, Obadiah G; Ginger, David S

    2010-05-18

    The use of organic photovoltaics (OPVs) could reduce production costs for solar cells because these materials are solution processable and can be manufactured by roll-to-roll printing. The nanoscale texture, or film morphology, of the donor/acceptor blends used in most OPVs is a critical variable that can dominate both the performance of new materials being optimized in the lab and efforts to move from laboratory-scale to factory-scale production. Although efficiencies of organic solar cells have improved significantly in recent years, progress in morphology optimization still occurs largely by trial and error, in part because much of our basic understanding of how nanoscale morphology affects the optoelectronic properties of these heterogeneous organic semiconductor films has to be inferred indirectly from macroscopic measurements. In this Account, we review the importance of nanoscale morphology in organic semiconductors and the use of electrical scanning probe microscopy techniques to directly probe the local optoelectronic properties of OPV devices. We have observed local heterogeneity of electronic properties and performance in a wide range of systems, including model polymer-fullerene blends such as poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C(61)-butyric acid methyl ester (PCBM), newer polyfluorene copolymer-PCBM blends, and even all polymer donor-acceptor blends. The observed heterogeneity in local photocurrent poses important questions, chiefly what information is contained and what is lost when using average values obtained from conventional measurements on macroscopic devices and bulk samples? We show that in many cases OPVs are best thought of as a collection of nanoscopic photodiodes connected in parallel, each with their own morphological and therefore electronic and optical properties. This local heterogeneity forces us to carefully consider the adequacy of describing OPVs solely by "average" properties such as the bulk carrier mobility

  14. Numerical investigation of viscoelastic flow induced crystallization in polymer processing

    NASA Astrophysics Data System (ADS)

    Mu, Yue; Zhao, Guoqun; Wu, Xianghong; Dong, Guiwei

    2013-05-01

    The investigation of viscoelastic flow induced crystallization is of great engineering significance in polymer processing like extrusion, injection and blow molding. In the study, the behavior of viscoelastic flow induced crystallization of semi-crystalline polymers is investigated by using finite element-finite difference method. The Schneider's approach is introduced to describe the evolution of crystallization kinetic process. The numerical model of three-dimensional flow induced crystallization of polymer melts obeying Phan-Thien and Tanner constitutive model is established. A penalty method is introduced to solve the nonlinear governing equations with a decoupled algorithm. The effect of flow state on the crystallization behavior is investigated. The crystalline distribution within the flow channel is obtained based on the proposed mathematical model and numerical method.

  15. Solution processed polymer tandem solar cell using efficient small and wide bandgap polymer:fullerene blends.

    PubMed

    Gevaerts, Veronique S; Furlan, Alice; Wienk, Martijn M; Turbiez, Mathieu; Janssen, René A J

    2012-04-24

    Solution processed polymer tandem solar cells that combine wide and small bandgap absorber layers reach a power conversion efficiency of 7% in a series configuration. This represents a 20% increase compared to the best single junction cells made with the individual active layers and shows that the tandem configuration reduces transmission and thermalization losses in converting sunlight. PMID:22438114

  16. Growing perovskite into polymers for easy-processable optoelectronic devices

    NASA Astrophysics Data System (ADS)

    Masi, Sofia; Colella, Silvia; Listorti, Andrea; Roiati, Vittoria; Liscio, Andrea; Palermo, Vincenzo; Rizzo, Aurora; Gigli, Giuseppe

    2015-01-01

    Here we conceive an innovative nanocomposite to endow hybrid perovskites with the easy processability of polymers, providing a tool to control film quality and material crystallinity. We verify that the employed semiconducting polymer, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), controls the self-assembly of CH3NH3PbI3 (MAPbI3) crystalline domains and favors the deposition of a very smooth and homogenous layer in one straightforward step. This idea offers a new paradigm for the implementation of polymer/perovskite nanocomposites towards versatile optoelectronic devices combined with the feasibility of mass production. As a proof-of-concept we propose the application of such nanocomposite in polymer solar cell architecture, demonstrating a power conversion efficiency up to 3%, to date the highest reported for MEH-PPV. On-purpose designed polymers are expected to suit the nanocomposite properties for the integration in diverse optoelectronic devices via facile processing condition.

  17. Growing perovskite into polymers for easy-processable optoelectronic devices

    PubMed Central

    Masi, Sofia; Colella, Silvia; Listorti, Andrea; Roiati, Vittoria; Liscio, Andrea; Palermo, Vincenzo; Rizzo, Aurora; Gigli, Giuseppe

    2015-01-01

    Here we conceive an innovative nanocomposite to endow hybrid perovskites with the easy processability of polymers, providing a tool to control film quality and material crystallinity. We verify that the employed semiconducting polymer, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), controls the self-assembly of CH3NH3PbI3 (MAPbI3) crystalline domains and favors the deposition of a very smooth and homogenous layer in one straightforward step. This idea offers a new paradigm for the implementation of polymer/perovskite nanocomposites towards versatile optoelectronic devices combined with the feasibility of mass production. As a proof-of-concept we propose the application of such nanocomposite in polymer solar cell architecture, demonstrating a power conversion efficiency up to 3%, to date the highest reported for MEH-PPV. On-purpose designed polymers are expected to suit the nanocomposite properties for the integration in diverse optoelectronic devices via facile processing condition. PMID:25579988

  18. Process for recovering filler from polymer

    DOEpatents

    Smith, Maurice L.; Smith, Robert M.

    1978-01-01

    This disclosure relates to a process for recovering filler material from a polymeric matrix by reacting the matrix at an elevated temperature in a gas atmosphere with a controlled oxidizing potential and thereafter separating and cleaning the residue from the reaction mixture.

  19. Diorganosilacetylene-alt-diorganosilvinylene polymers and a process of preparation

    DOEpatents

    Barton, Thomas J.; Ijadi-Maghsoodi, Sina; Pang, Yi

    1993-08-31

    The present invention provides linear organosilicon polymers including acetylene and vinylene moieties, and a process for their preparation. These diorganosilacetylenealt-diorganosilvinylene linear polymers can be represented by the formula: --[--(R.sup.1)(R.sup.2)Si--C.ident.C--(R.sup.3)(R.sup.4)Si--CH=CH--].sub.n --, wherein n.gtoreq.2; each R.sup.1, R.sup.2, R.sup.3, and R.sup.4 is independently selected from the group consisting of hydrogen, halogen, alkyl, alkenyl, aryl, and aralkyl radicals. The polymers are soluble in organic solvents, air stable, and can be pulled into fibers or cast into films. They can be thermally converted into silicon carbide ceramic materials.

  20. Diorganosilacetylene-alt-diorganosilvinylene polymers and a process of preparation

    DOEpatents

    Barton, T.J.; Ijadi-Maghsoodi, S.; Pang, Y.

    1995-10-10

    The present invention provides linear organosilicon polymers including acetylene and vinylene moieties, and a process for their preparation. These diorganosilacetylene-alt-diorganosilvinylene linear polymers can be represented by the formula: --[--(R{sup 1})(R{sup 2})Si--C{triple_bond}C--(R{sup 3})(R{sup 4})Si--CH{double_bond}CH--]{sub n}--, wherein n{>=}2; and each R{sup 1}, R{sup 2}, R{sup 3}, and R{sup 4} is independently selected from the group consisting of hydrogen, halogen, alkyl, alkenyl, aryl, and aralkyl radicals. The polymers are soluble in organic solvents, air stable, and can be pulled into fibers or cast into films. They can be thermally converted into silicon carbide ceramic materials.

  1. Diorganosilacetylene-alt-diorganosilvinylene polymers and a process of preparation

    DOEpatents

    Barton, Thomas J.; Ijadi-Maghsoodi, Sina; Pang, Yi

    1995-10-10

    The present invention provides linear organosilicon polymers including acetylene and vinylene moieties, and a process for their preparation. These diorganosilacetylene-alt-diorganosilvinylene linear polymers can be represented by the formula: --[--(R.sup.1)(R.sup.2)Si--C.tbd.C--(R.sup.3)(R.sup.4)Si--CH.dbd.CH--].sub .n --, wherein n.gtoreq.2; and each R.sup.1, R.sup.2, R.sup.3, and R.sup.4 is independently selected from the group consisting of hydrogen, halogen, alkyl, alkenyl, aryl, and aralkyl radicals. The polymers are soluble in organic solvents, air stable, and can be pulled into fibers or cast into films. They can be thermally converted into silicon carbide ceramic materials.

  2. Diorganosilacetylene-alt-diorganosilvinylene polymers and a process of preparation

    DOEpatents

    Barton, T.J.; Ijadi-Maghsoodi, S.; Yi Pang.

    1993-08-31

    The present invention provides linear organosilicon polymers including acetylene and vinylene moieties, and a process for their preparation. These diorganosilacetylene-alt-diorganosilvinylene linear polymers can be represented by the formula: -[-(R[sup 1])(R[sup 2])Si-C[triple bond]C-(R[sup 3])(R[sup 4])Si-CH[double bond]CH-][sub n]-, wherein n[>=]2; each R[sup 1], R[sup 2], R[sup 3], and R[sup 4] is independently selected from the group consisting of hydrogen, halogen, alkyl, alkenyl, aryl, and aralkyl radicals. The polymers are soluble in organic solvents, air stable, and can be pulled into fibers or cast into films. They can be thermally converted into silicon carbide ceramic materials.

  3. Polymerization and processing of organic polymers in a magnetic field

    SciTech Connect

    Douglas, E.P.

    1995-05-01

    The use of magnetic fields to affect the structure and properties of polymeric materials remains an area of great promise. Liquid crystalline polymers have been actively studied over the past 20 years for use in high performance structural applications. In particular, highly oriented fibers can exhibit remarkable increases in strength to weight performance compared to conventional materials. For example, the fibers marketed by DuPont under the tradename Kevlar are 20 times stronger than steel on an equivalent weight basis. However, larger bulk parts do not exhibit the same increases in strength due to a lack of orientation of the polymer molecules. Magnetic field processing of polymers remains an attractive solution to this problem.

  4. Laser processing of components for polymer mircofluidic and optoelectronic products

    NASA Astrophysics Data System (ADS)

    Gillner, Arnold; Bremus-Koebberling, Elke A.; Wehner, Martin; Russek, Ulrich A.; Berden, Thomas

    2001-06-01

    Miniaturization is one of the keywords for the production of customer oriented and highly integrated consumer products like mobile phones, portables and other products from the daily life and there are some first silicon made products like pressure sensors, acceleration sensors and micro fluidic components, which are built in automobiles, washing machines and medical products. However, not all applications can be covered with this material, because of the limitations in lateral and 3-dimensional structuring, the mechanical behavior, the functionality and the costs of silicon. Therefore other materials, like polymers have been selected as suitable candidates for cost effective mass products. This holds especially for medical and optical applications, where the properties of selected polymers, like biocompatibility, inert chemical behavior and high transparency can be used. For this material laser micro processing offers appropriate solutions for structuring as well as for packaging with high flexibility, material variety, structure size, processing speed and easy integration into existing fabrication plants. The paper presents recent results and industrial applications of laser micro processing for polymer micro fluidic devices, like micro analysis systems, micro reactors and medical micro implants, where excimer radiation is used for lateral structuring and diode lasers have used for joining and packaging. Similar technologies have been applied to polymer waveguides to produce passive optoelectronic components for high speed interconnection with surface roughness less than 20 nm and low attenuation. The paper also reviews the technical and economical limitations and the potential of the technology for other micro products.

  5. Tough, processable semi-interpenetrating polymer networks from monomer reactants

    NASA Technical Reports Server (NTRS)

    Pater, Ruth H. (Inventor)

    1994-01-01

    A high temperature semi-interpenetrating polymer network (semi-IPN) was developed which had significantly improved processability, damage tolerance, and mechanical performance, when compared to the commercial Thermid materials. This simultaneous semi-IPN was prepared by mixing the monomer precursors of Thermid AL-600 (a thermoset) and NR-150B2 (a thermoplastic) and allowing the monomers to react randomly upon heating. This reaction occurs at a rate which decreases the flow and broadens the processing window. Upon heating at a higher temperature, there is an increase in flow. Because of the improved flow properties, broadened processing window and enhanced toughness, high strength polymer matrix composites, adhesives and molded articles can now be prepared from the acetylene end-capped polyimides which were previously inherently brittle and difficult to process.

  6. Observation and Analysis of Polymer Crystal Structures at the Stem Level. Implications Regarding Polymer Crystallization Processes.

    NASA Astrophysics Data System (ADS)

    Lotz, Bernard

    2003-03-01

    The building element of chain folded polymer crystals is the individual stem that spans the lamellar thickness. For chiral but racemic helical polymers such as polyolefins (e.g. isotactic and syndiotactic polypropylene and poly(1-butene)), stems can be right- or left-handed helices. These polymers can exist in various crystal polymorphs that are either "racemic" or "chiral" (made of both, or of only one helical hand). Upon crystallization, each stem has a conformational "choice", but must adapt to the crystal structure and, once crystallized, is characterized by a "conformational tag" (right or left hand). Various means exist to determine or observe helical hands in polyolefin lamellae: Atomic Force Microscopy on epitaxially crystallized samples, or, for the alpha phase of isotactic polypropylene, analysis of its specific lamellar branching. These observations and analyses indicate that the helical hand of stems is tightly determined by the substrate or growth face topography, i.e. indicate that the depositing stem probes and adapts to the surface structure prior to successful attachment. This "post-mortem" analysis of the crystal structure and stem chirality emphasizes the "sequential" nature of the growth process (successive attachment of individual stems). It is in line with early views on polymer crystallization. It is at variance with recently introduced models or scenarios that assume either some pre-ordering of the polymer melt as a result of spinodal decomposition and/or accretion of polymer chains in pseudo-crystalline bundles followed by (solid state) reorganization of the bundles to generate fully grown lamellae.

  7. n-Type Water/Alcohol-Soluble Naphthalene Diimide-Based Conjugated Polymers for High-Performance Polymer Solar Cells.

    PubMed

    Wu, Zhihong; Sun, Chen; Dong, Sheng; Jiang, Xiao-Fang; Wu, Siping; Wu, Hongbin; Yip, Hin-Lap; Huang, Fei; Cao, Yong

    2016-02-17

    organic photovoltaic modules based on roll-to-roll coating processes. PMID:26794827

  8. n-Type Water/Alcohol-Soluble Naphthalene Diimide-Based Conjugated Polymers for High-Performance Polymer Solar Cells.

    PubMed

    Wu, Zhihong; Sun, Chen; Dong, Sheng; Jiang, Xiao-Fang; Wu, Siping; Wu, Hongbin; Yip, Hin-Lap; Huang, Fei; Cao, Yong

    2016-02-17

    organic photovoltaic modules based on roll-to-roll coating processes.

  9. Nonlinear optical polymers for electro-optic signal processing

    NASA Technical Reports Server (NTRS)

    Lindsay, Geoffrey A.

    1991-01-01

    Photonics is an emerging technology, slated for rapid growth in communications systems, sensors, imagers, and computers. Its growth is driven by the need for speed, reliability, and low cost. New nonlinear polymeric materials will be a key technology in the new wave of photonics devices. Electron-conjubated polymeric materials offer large electro-optic figures of merit, ease of processing into films and fibers, ruggedness, low cost, and a plethora of design options. Several new broad classes of second-order nonlinear optical polymers were developed at the Navy's Michelson Laboratory at China Lake, California. Polar alignment in thin film waveguides was achieved by electric-field poling and Langmuir-Blodgett processing. Our polymers have high softening temperatures and good aging properties. While most of the films can be photobleached with ultraviolet (UV) light, some have excellent stability in the 500-1600 nm range, and UV stability in the 290-310 nm range. The optical nonlinear response of these polymers is subpicosecond. Electro-optic switches, frequency doublers, light modulators, and optical data storage media are some of the device applications anticipated for these polymers.

  10. Application of polymer membrane technology in coal combustion processes

    SciTech Connect

    Kaldis, S.P.; Skodras, G.; Grammelis, P.; Sakellaropoulos, G.P.

    2007-03-15

    The energy efficiency and the environmental consequences of typical coal upgrading processes, such as combustion, depend to a large extent on the degree of gas separation, recovery, and recycle. Among the available methods used in chemical industry for a variety of gas separation tasks, the technology of polymer membranes offers several advantages such as low size, simplicity of operation and maintenance, compatibility, and use with a diversity of fuel sources. To examine the impact of membrane separation on coal upgrading processes, the Aspen Plus simulation software was used, in combination with developed membrane mathematical models. Energy analysis in coal combustion processes, where the main scope is CO{sub 2} removal, showed that very promising results can be attained. It is estimated that 95% of the emitted CO{sub 2} can be captured with a moderately low energy penalty (10%). This penalty can be further decreased if higher selectivity and/or permeability polymers can be developed.

  11. Study on degradation process of polymer electrolyte by solution analysis

    NASA Astrophysics Data System (ADS)

    Akiyama, Yoko; Sodaye, Hemant; Shibahara, Yuji; Honda, Yoshihide; Tagawa, Seiichi; Nishijima, Shigehiro

    Degradation process of Nafion which is one of the polymer electrolyte generally used for polymer electrolyte membrane fuel cell was investigated by solution analysis and structural analysis of eluted species. Nafion degraded by gamma-ray irradiation and heat treatment was immersed in distilled water and the solutions were analyzed using ion chromatograph, total organic carbon (TOC) analyzer, and inductively coupled plasma atomic emission spectrometer (ICP-AES). The solutions after the Fenton reaction were also analyzed with the same methods. Proton, sulfide ion, fluorine ion and organic carbon were eliminated into the solution, and their ratio was changed depending on the degradation method. To determine the eliminated species to the solution, structural analysis of concentrated dissolved species was performed using FT-IR. As the results, the initial process of degradation was detected sensitively in solution analysis compared with membrane analysis, and difference of the degradation process under different conditions was clearly observed. It was also found that new functional group COOH was formed in the eliminated species. These results showed that solution analysis are very simple yet powerful methods to elucidate the degradation process, which can also be applied to actual fuel cell operation to track minute changes in the polymer electrolyte.

  12. Glass transition and relaxation processes of nanocomposite polymer electrolytes.

    PubMed

    Money, Benson K; Hariharan, K; Swenson, Jan

    2012-07-01

    This study focus on the effect of δ-Al(2)O(3) nanofillers on the dc-conductivity, glass transition, and dielectric relaxations in the polymer electrolyte (PEO)(4):LiClO(4). The results show that there are three dielectric relaxation processes, α, β, and γ, in the systems, although the structural α-relaxation is hidden in the strong conductivity contribution and could therefore not be directly observed. However, by comparing an enhanced dc-conductivity, by approximately 2 orders of magnitude with 4 wt % δ-Al(2)O(3) added, with a decrease in calorimetric glass transition temperature, we are able to conclude that the dc-conductivity is directly coupled to the hidden α-relaxation, even in the presence of nanofillers (at least in the case of δ-Al(2)O(3) nanofillers at concentrations up to 4 wt %). This filler induced speeding up of the segmental polymer dynamics, i.e., the α-relaxation, can be explained by the nonattractive nature of the polymer-filler interactions, which enhance the "free volume" and mobility of polymer segments in the vicinity of filler surfaces. PMID:22686254

  13. Fabrication of Metal Embedded Polymer Periodic Nanostructures by Nanoimprint Process

    NASA Astrophysics Data System (ADS)

    Ogai, Noriyuki; Sugimura, Ryo; Takiguchi, Yoshihiro

    Many nano-application research have been conducted with development of nanoimprint technologies. In particular, metal or metal-polymer hybrid nanostructures have great potentials as nano-devices such as localized surface plasmon resonance (LSPR) devices, wire grid polarizer (WGP) and organic electronics. The metal embedded polymer periodic nanostructures are also expected as a control substrate to array nanoparticles at three dimensional photonic crystal (3DPC). In this study, we propose and demonstrate new fabrication process based on a combination technique of vacuum evaporation and nanoimprint as a fabrication method for the metal embedded nanostructures. As the result, the PMMA nanodot array (approximate 100 nm in diameter with 300 nm pitch) with gold round films embedded at their bottoms were fabricated successfully using this method. Application to 3DPC and other nanodevices of these nanostructures and fabrication process are described.

  14. Nano-structured polymer composites and process for preparing same

    DOEpatents

    Hillmyer, Marc; Chen, Liang

    2013-04-16

    A process for preparing a polymer composite that includes reacting (a) a multi-functional monomer and (b) a block copolymer comprising (i) a first block and (ii) a second block that includes a functional group capable of reacting with the multi-functional monomer, to form a crosslinked, nano-structured, bi-continuous composite. The composite includes a continuous matrix phase and a second continuous phase comprising the first block of the block copolymer.

  15. The Rheology and Processing of Renewable Resource Polymers

    NASA Astrophysics Data System (ADS)

    Conrad, Jason D.; Harrison, Graham M.

    2008-07-01

    Bio-based polymers offer an alternative to conventional fossil fuel-based materials, in particular for commodity applications such as single-use products. In this work, we report on the rheology and processing of two bio-based polymers, namely poly-hydroxyalkanoate (PHA) copolymers and poly-lactic acid (PLA), and their blends. These materials are derived from renewable resources, and can degrade under the appropriate conditions. The rheology is investigated in shear, elongation, and transient modes. Of particular importance is the degradation of these materials at typical processing conditions, and the impact of polymer architecture on the extensional properties. Using results from these rheological investigations, appropriate thermal and flow conditions are employed in a DSM Xplore microcompounder, with the cast film attachment, to produce films of PHA copolymers blended with PLA. The resultant films are characterized, as a function of both material composition and processing history, using DSC, WAXD, tensile testing, and SEM, to investigate the effect of varying PHA content on the final properties.

  16. Impact of polymer film thickness and cavity size on polymer flow during embossing : towards process design rules for nanoimprint lithography.

    SciTech Connect

    Schunk, Peter Randall; King, William P. (Georgia Institute of Technology, Atlanta, GA); Sun, Amy Cha-Tien; Rowland, Harry D.

    2006-08-01

    This paper presents continuum simulations of polymer flow during nanoimprint lithography (NIL). The simulations capture the underlying physics of polymer flow from the nanometer to millimeter length scale and examine geometry and thermophysical process quantities affecting cavity filling. Variations in embossing tool geometry and polymer film thickness during viscous flow distinguish different flow driving mechanisms. Three parameters can predict polymer deformation mode: cavity width to polymer thickness ratio, polymer supply ratio, and Capillary number. The ratio of cavity width to initial polymer film thickness determines vertically or laterally dominant deformation. The ratio of indenter width to residual film thickness measures polymer supply beneath the indenter which determines Stokes or squeeze flow. The local geometry ratios can predict a fill time based on laminar flow between plates, Stokes flow, or squeeze flow. Characteristic NIL capillary number based on geometry-dependent fill time distinguishes between capillary or viscous driven flows. The three parameters predict filling modes observed in published studies of NIL deformation over nanometer to millimeter length scales. The work seeks to establish process design rules for NIL and to provide tools for the rational design of NIL master templates, resist polymers, and process parameters.

  17. Interfacial Behavior of Polymers: Using Interfaces to Manipulate Polymers

    SciTech Connect

    Russell, Thomas P.

    2015-02-26

    most rapid solvent removal process drives the copolymer film to below its glass transition temperature, freezing in the lateral order. We have quantitatively described the ordering and the parameters influencing the disruption of the ordering in these studies. We have also used e-beam lithography to generate shallow trench patterns on planar surface where the topographic patterning provides an additional constraint on the self-assembly of the block copolymer. The pitches of the trenches were varied while the depth and the trench width of patterns were maintained by constant at 89 and 30nm, respectively. Unidirectional PS-b-PEO line patterns over large area on the shallow trench patterns were obtained by solvent vapor annealing. We extended the solvent annealing process to an in-line coating process using a mini-slot die coater developed in our laboratories. This coater uses minimal materials with operating parameters that can mimic actual industrial processing on a roll-to-roll line. Most important, with this mini-slot die coater, it could also characterize the structure of the film using grazing incidence x-ray scattering. Using the fundamental characterization of the ordering of the block copolymers, we could optimize the coating conditions to enhance lateral ordering of block copolymer in a well-defined manner. The structures produced in this process are directly transferable to flexible electronics where the arrays of block copolymer microdomains can be used for the fabrication of nanostructured components. We have also controlled the orientation of BCP microdomains at the air and substrate interfaces by manipulating the interfacial interactions with selective solvents. This has enabled us to generate nanoporous membranes where the size of the pores is dictated by the size of the bloc copolymer microdomains. We have produced robust nanoporous membranes that can tolerate high pressures and have high throughput using thick films of block copolymers. Exceptional size

  18. Process optimization of ultrasonic spray coating of polymer films.

    PubMed

    Bose, Sanjukta; Keller, Stephan S; Alstrøm, Tommy S; Boisen, Anja; Almdal, Kristoffer

    2013-06-11

    In this work we have performed a detailed study of the influence of various parameters on spray coating of polymer films. Our aim is to produce polymer films of uniform thickness (500 nm to 1 μm) and low roughness compared to the film thickness. The coatings are characterized with respect to thickness, roughness (profilometer), and morphology (optical microscopy). Polyvinylpyrrolidone (PVP) is used to do a full factorial design of experiments with selected process parameters such as temperature, distance between spray nozzle and substrate, and speed of the spray nozzle. A mathematical model is developed for statistical analysis which identifies the distance between nozzle and substrate as the most significant parameter. Depending on the drying of the sprayed droplets on the substrate, we define two broad regimes, "dry" and "wet". The optimum condition of spraying lies in a narrow window between these two regimes, where we obtain a film of desired quality. Both with increasing nozzle-substrate distance and temperature, the deposition moves from a wet state to a dry regime. Similar results are also achieved for solvents with low boiling points. Finally, we study film formation during spray coating with poly (D,L-lactide) (PDLLA). The results confirm the processing knowledge obtained with PVP and indicate that the observed trends are identical for spraying of other polymer films.

  19. Process optimization of ultrasonic spray coating of polymer films.

    PubMed

    Bose, Sanjukta; Keller, Stephan S; Alstrøm, Tommy S; Boisen, Anja; Almdal, Kristoffer

    2013-06-11

    In this work we have performed a detailed study of the influence of various parameters on spray coating of polymer films. Our aim is to produce polymer films of uniform thickness (500 nm to 1 μm) and low roughness compared to the film thickness. The coatings are characterized with respect to thickness, roughness (profilometer), and morphology (optical microscopy). Polyvinylpyrrolidone (PVP) is used to do a full factorial design of experiments with selected process parameters such as temperature, distance between spray nozzle and substrate, and speed of the spray nozzle. A mathematical model is developed for statistical analysis which identifies the distance between nozzle and substrate as the most significant parameter. Depending on the drying of the sprayed droplets on the substrate, we define two broad regimes, "dry" and "wet". The optimum condition of spraying lies in a narrow window between these two regimes, where we obtain a film of desired quality. Both with increasing nozzle-substrate distance and temperature, the deposition moves from a wet state to a dry regime. Similar results are also achieved for solvents with low boiling points. Finally, we study film formation during spray coating with poly (D,L-lactide) (PDLLA). The results confirm the processing knowledge obtained with PVP and indicate that the observed trends are identical for spraying of other polymer films. PMID:23631433

  20. Mechanisms of shark skin suppression by novel polymer processing aids

    NASA Astrophysics Data System (ADS)

    Wagner, M. H.; Himmel, T.; Kulikov, O.; Hornung, K.

    2014-05-01

    The extrusion rate of polyethylene (PE) with narrow molar weight distribution, as e.g. metallocen catalysed polyethylene (m-PE), is limited by melt fracture. The first level of fracture is a surface defect called sharkskin. Common polymer processing aids based on fluorinated polymers shift the onset of sharkskin to higher extrusion rates by creating a "low energy surface" at the die wall and promoting wall slip. Alternatively, Kulikov et al. [1, 2] suggested thermoplastic elastomers (TPE) for sharkskin suppression, and Müller [3] showed the suitability of some TPEs as polymer processing aids. We investigated the slip velocity of several TPEs against steel, and the slip velocity in a polymeric interface between polyethylene (PE) and TPE by rotational plate-plate rheometry in the Newtonian flow regime. TPEs with lower viscosities showed higher slip velocities against steel. However, the interfacial slip velocities between PE and TPE were found to be viscosity independent. In both cases, the slip velocity was found to be proportional to the applied shear stress.

  1. Bridging Microstructure, Properties and Processing of Polymer Based Advanced Materials

    SciTech Connect

    Li, Dongsheng; Ahzi, Said; Khaleel, Mohammad A.

    2012-01-01

    This is a guest editorial for a special issue in Journal of Engineering Materials and Technology. The papers collected in this special issue emphasize significant challenges, current approaches and future strategies necessary to advance the development of polymer-based materials. They were partly presented at the symposium of 'Bridging microstructure, properties and processing of polymer based advanced materials' in the TMS 2011 annual conference meeting, which was held in San Diego, US, on Feb 28 to March 3, 2011. This symposium was organized by the Pacific Northwest National Laboratory (USA) and the Institute of Mechanics of Fluids and Solids of the University of Strasbourg (France). The organizers were D.S. Li, S. Ahzi, and M. Khaleel.

  2. Asymmetric Diketopyrrolopyrrole Conjugated Polymers for Field-Effect Transistors and Polymer Solar Cells Processed from a Nonchlorinated Solvent.

    PubMed

    Ji, Yunjing; Xiao, Chengyi; Wang, Qiang; Zhang, Jianqi; Li, Cheng; Wu, Yonggang; Wei, Zhixiang; Zhan, Xiaowei; Hu, Wenping; Wang, Zhaohui; Janssen, René A J; Li, Weiwei

    2016-02-01

    Newly designed asymmetric diketopyrrolopyrrole conjugated polymers with two different aromatic substituents possess a hole mobility of 12.5 cm(2) V(-1) s(-1) in field-effect transistors and a power conversion efficiency of 6.5% in polymer solar cells, when solution processed from a nonchlorinated toluene/diphenyl ether mixed solvent.

  3. Processable high-carbon-yielding polymer for micro- and nanofabrication

    NASA Astrophysics Data System (ADS)

    Perpall, Mark W.; Zengin, Huseyin; Perera, K. Prasanna U.; Zhou, Wensheng; Shah, Hiren; Wu, Xinyu; Creager, Stephen E.; Smith, Dennis W., Jr.; Foulger, Stephen H.; Ballato, John M.

    2003-01-01

    Bis-ortho-Diynyl Arene (BODA) monomers polymerize to network polynapthalene by the thermally-driven Bergman cyclization and subsequent radical polymerization via oligomeric intermediates that can be melt or solution processed. Further heating of the network to 1000 °C affords a high-yield glassy carbon structure that retains the approximate size and dimensions of the polymer precursor. The higher carbon-yield for BODA networks (75- 80 % by mass) is significantly greater than that of traditional phenol-formaldehyde resins and other carbon precursor polymers leading to its greater dimensional stability. Phenyl terminated BODA derived polymers were fabricated using microprocessing such as the micromolding in capillaries (MIMIC) technique, direct microtransfer molding, and molding in quartz capillary tubes. Nano-scale fabrication using closed packed silica spheres as templates was demonstrated with an hydroxy-terminated monomer which exhibits greatly enhanced compatibility for silica surfaces. After pyrolysis to glassy carbon, the silica is chemically etched leaving an inverse carbon opal photonic crystal which is electrically conductive. The wavelength of light diffracted is a function of the average refractive index of the carbon/ filler composite, which can be modified for use as sensitive detector elements.

  4. Optical characterization of thin nickel films on polymer substrates using reflectance difference spectroscopy

    SciTech Connect

    Rinnerbauer, V.; Schmidegg, K.; Hohage, M.; Sun, L. D.; Flores-Camacho, J. M.; Zeppenfeld, P.

    2009-06-15

    We have used reflectance difference spectroscopy (RDS) and its extension, azimuth-dependent RDS (ADRDS), to study the properties of sputtered and evaporated nickel films on biaxially oriented poly(ethylene terephtalate) (PET) films in a roll to roll web-coating process. From the full set of ADRDS spectra we extract and analyze both the intrinsic RDS spectra and the azimuthal orientation of the effective optical anisotropy of the samples. From the latter, contributions to the RDS spectra arising from the nickel layer and the PET substrate with different orientations of the optical eigenaxes can be inferred. We find an attenuation of the characteristic RDS signal of the PET substrate with increasing nickel film thickness which is in good agreement with the theoretical prediction. For film thicknesses above 20 nm another contribution to the RDS signal attributed to the optical anisotropy of the deposited nickel layers can be observed. Its strength depends on the deposition method, and is considerably larger for evaporated films than for sputtered ones. With increasing nickel film thickness, the azimuthal orientation of the sample anisotropy changes from the initial value of the PET substrate by about 20 deg.toward the machine direction of the foil. We demonstrate that RDS is also a valuable tool for inline monitoring in the roll to roll process, as the attenuation of the RDS signal, under proper consideration of the orientation of the effective anisotropy, is a function of the film thickness and characteristic for the deposited material.

  5. Removal of Pu-238 from aqueous process streams using a polymer filtration process

    NASA Astrophysics Data System (ADS)

    Jarvinen, Gordon D.; Purdy, Geraldine M.; Rau, Karen C.; Remeroski, M. L.; Reimus, Mary Ann H.; Ramsey, Kevin B.; Foltyn, Elizabeth M.; Smith, Barbara F.; Robison, Thomas W.

    2001-02-01

    A glovebox facility is under construction at Los Alamos that will recover a significant quantity of the impure Pu-238 that exists in scrap and residues from past production operations. The general flowsheet consists of milling, acid dissolution, ion exchange, precipitation, calcination, oxygen isotope exchange, and waste treatment operations. As part of the waste treatment operations we are using polymer filtration to remove Pu-238 to meet facility discharge limits. Polymer filtration (PF) technology uses water-soluble polymers prepared with selective receptor sites to sequester metal ions, organic molecules, and other species from dilute aqueous solutions. The water-soluble polymers have a sufficiently large molecular size that they can be separated and concentrated using ultrafiltration (UF) methods. Water and small, unbound components of the solution pass freely through the UF membrane while the polymer concentrates in the retentate. The permeate stream is ``cleaned'' of the components bound to the polymer and can be used in further processing steps or discharged. The concentrated retentate solution can be treated to give a final waste form or to release the sequestered species from the receptor sites by adjusting the conditions in the retentate solution. The PF technology is part of our work to develop a safe, reliable and cost-effective scrap recovery operation with high process efficiencies, minimal waste generation, and high product purity. .

  6. Long-lived charge carrier dynamics in polymer/quantum dot blends and organometal halide perovskites

    NASA Astrophysics Data System (ADS)

    Nagaoka, Hirokazu

    Solution-processable semiconductors offer a potential route to deploy solar panels on a wide scale, based on the possibility of reduced manufacturing costs by using earth-abundant materials and inexpensive production technologies, such as inkjet or roll-to-roll printing. Understanding the fundamental physics underlying device operation is important to realize this goal. This dissertation describes studies of two kinds of solar cells: hybrid polymer/PbS quantum dot solar cells and organometal halide perovskite solar cells. Chapter two discusses details of the experimental techniques. Chapter three and four explore the mechanisms of charge transfer and energy transfer spectroscopically, and find that both processes contribute to the device photocurrent. Chapter four investigates the important question of how the energy level alignment of quantum dot acceptors affects the operation of hybrid polymer/quantum dot solar cells, by making use of the size-tunable energy levels of PbS quantum dots. We observe that long-lived charge transfer yield is diminished at larger dot sizes as the energy level offset at the polymer/quantum dot interface is changed through decreasing quantum confinement using a combination of spectroscopy and device studies. Chapter five discusses the effects of TiO2 surface chemistry on the performance of organometal halide perovskite solar cells. Specifically, chapter five studies the effect of replacing the conventional TiO2 electrode with Zr-doped TiO2 (Zr-TiO2). We aim to explore the correlation between charge carrier dynamics and device studies by incorporating zirconium into TiO2. We find that, compared to Zr-free controls, solar cells employing Zr-TiO2 give rise to an increase in overall power conversion efficiency, and a decrease in hysteresis. We also observe longer carrier lifetimes and higher charge carrier densities in devices on Zr-TiO2 electrodes at microsecond times in transient photovoltage experiments, as well as at longer persistent

  7. Robotic Deposition of TiO2 Films on Flexible Substrates from Hybrid Inks: Investigation of Synthesis-Processing-Microstructure-Photocatalytic Relationships.

    PubMed

    Torres Arango, Maria A; Valença de Andrade, Alana S; Cipollone, Domenic T; Grant, Lynnora O; Korakakis, Dimitris; Sierros, Konstantinos A

    2016-09-21

    TiO2 is an important material widely used in optoelectronic devices due to its semiconducting and photocatalytic properties, nontoxicity, and chemically inert nature. Some indicative applications include water purification systems and energy harvesting. The use of solution, water-based inks for the direct writing of TiO2 on flexible substrates is of paramount importance since it enables low-cost and low-energy intensive large-area manufacturing, compatible with roll-to-roll processing. In this work we study the effect of crystalline TiO2 and polymer addition on the rheological and direct writing properties of Ti-organic/TiO2 inks. We also report on the bridging crystallite formation from the Ti-organic precursor into the TiO2 crystalline phase, under ultraviolet (UV) exposure or mild heat treatments up to 150 °C. Such crystallite formation is found to be enhanced by polymers with strong polarity and pKα such as polyacrylic acid (PAA). X-ray diffraction (XRD) coupled with Raman and X-ray photoelectron (XPS) spectroscopy are used to investigate the crystalline-phase transformation dependence based on the initial TiO2 crystalline-phase concentration and polymer addition. Transmission electron microscopy imaging and selected area electron diffraction patterns confirm the crystalline nature of such bridging printed structures. The obtained inks are patterned on flexible substrates using nozzle-based robotic deposition, a lithography-free, additive manufacturing technique that allows the direct writing of material in specific, digitally predefined, substrate locations. Photocatalytic degradation of methylene blue solutions highlights the potential of the studied films for chemical degradation applications, from low-cost environmentally friendly materials systems.

  8. Robotic Deposition of TiO2 Films on Flexible Substrates from Hybrid Inks: Investigation of Synthesis-Processing-Microstructure-Photocatalytic Relationships.

    PubMed

    Torres Arango, Maria A; Valença de Andrade, Alana S; Cipollone, Domenic T; Grant, Lynnora O; Korakakis, Dimitris; Sierros, Konstantinos A

    2016-09-21

    TiO2 is an important material widely used in optoelectronic devices due to its semiconducting and photocatalytic properties, nontoxicity, and chemically inert nature. Some indicative applications include water purification systems and energy harvesting. The use of solution, water-based inks for the direct writing of TiO2 on flexible substrates is of paramount importance since it enables low-cost and low-energy intensive large-area manufacturing, compatible with roll-to-roll processing. In this work we study the effect of crystalline TiO2 and polymer addition on the rheological and direct writing properties of Ti-organic/TiO2 inks. We also report on the bridging crystallite formation from the Ti-organic precursor into the TiO2 crystalline phase, under ultraviolet (UV) exposure or mild heat treatments up to 150 °C. Such crystallite formation is found to be enhanced by polymers with strong polarity and pKα such as polyacrylic acid (PAA). X-ray diffraction (XRD) coupled with Raman and X-ray photoelectron (XPS) spectroscopy are used to investigate the crystalline-phase transformation dependence based on the initial TiO2 crystalline-phase concentration and polymer addition. Transmission electron microscopy imaging and selected area electron diffraction patterns confirm the crystalline nature of such bridging printed structures. The obtained inks are patterned on flexible substrates using nozzle-based robotic deposition, a lithography-free, additive manufacturing technique that allows the direct writing of material in specific, digitally predefined, substrate locations. Photocatalytic degradation of methylene blue solutions highlights the potential of the studied films for chemical degradation applications, from low-cost environmentally friendly materials systems. PMID:27568659

  9. The development of compact electroactive polymer actuators suitable for use in full page Braille displays

    NASA Astrophysics Data System (ADS)

    Gorny, Lee J.; Zellers, Brian C.; Lin, Minren; Liu, Sheng; Zhang, Qiming M.

    2010-04-01

    Piezoceramic actuators, presently used in commercial Braille displays, are limited by the material's relatively small strain and brittle nature. For this reason, it is a challenge to develop full page, compact, graphic Braille displays that are affordable. A newly developed material composed of P(VDF-TrFE-CFE) terpolymer blended with 5% P(VDF-CTFE) electrostrictive actuators exhibits large strains (~5% at 150V/μm), fast actuation (>5 mm/s), and has a relatively high elastic modulus (1.2 GPa). This material exhibits more than double the elastic energy density and a 50% higher modulus of the original electrostrictive terpolymer. Hence, the potential for viable actuators in compact, full page Braille displays is greater than ever, provided actuators can be manufactured reliably in quantity. This talk presents recent work in scaling production of such rolled actuators. Actuators extend .5 mm, are confined to the 2.5 mm grid spacing of conventional Braille text, generate >0.5 N force and operate at less than 200V, thus meeting the primary requirements for a commercialized Braille display. To manufacture these actuators, cast films are stretched using a roll-to-roll zone drawing machine that is capable of producing quantities of 2 μm thick film with high quality. What follows is a discussion of this machine, the roll-to-roll film stretching process and an assessment of the resulting stretched film for use as linear strain actuators, like those used in our Braille cell.

  10. Process for preparing tapes from thermoplastic polymers and carbon fibers

    NASA Technical Reports Server (NTRS)

    Chung, Tai-Shung (Inventor); Furst, Howard (Inventor); Gurion, Zev (Inventor); McMahon, Paul E. (Inventor); Orwoll, Richard D. (Inventor); Palangio, Daniel (Inventor)

    1986-01-01

    The instant invention involves a process for use in preparing tapes or rovings, which are formed from a thermoplastic material used to impregnate longitudinally extended bundles of carbon fibers. The process involves the steps of (a) gas spreading a tow of carbon fibers; (b) feeding the spread tow into a crosshead die; (c) impregnating the tow in the die with a thermoplastic polymer; (d) withdrawing the impregnated tow from the die; and (e) gas cooling the impregnated tow with a jet of air. The crosshead die useful in the instant invention includes a horizontally extended, carbon fiber bundle inlet channel, means for providing melted polymer under pressure to the die, means for dividing the polymeric material flowing into the die into an upper flow channel and a lower flow channel disposed above and below the moving carbon fiber bundle, means for applying the thermoplastic material from both the upper and lower channels to the fiber bundle, and means for withdrawing the resulting tape from the die.

  11. Low thermal budget photonic processing of highly conductive Cu interconnects based on CuO nanoinks. Potential for flexible printed electronics

    DOE PAGES

    Rager, Matthew S.; Aytug, Tolga; Veith, Gabriel M.; Joshi, Pooran C.

    2015-12-31

    The developing field of printed electronics nanoparticle based inks such as CuO show great promise as a low-cost alternative to other metal-based counterparts (e.g., silver). In particular, CuO inks significantly eliminate the issue of particle oxidation, before and during the sintering process, that is prevalent in Cu-based formulations. We report here the scalable and low-thermal budget photonic fabrication of Cu interconnects employing a roll-to-roll compatible pulse-thermal-processing (PTP) technique that enables phase reduction and subsequent sintering of inkjet-printed CuO patterns onto flexible polymer templates. Detailed investigations of curing and sintering conditions were performed to understand the impact of PTP system conditionsmore » on the electrical performance of the Cu patterns. Specifically, the impact of energy and power of photonic pulses on print conductivity was systematically studied by varying the following key processing parameters: pulse intensity, duration and sequence. Through optimization of such parameters, highly conductive prints in < 1 s with resistivity values as low as 100 n m has been achieved. We also observed that the introduction of an initial ink-drying step in ambient atmosphere, after the printing and before sintering, leads to significant improvements in mechanical integrity and electrical performance of the printed Cu patterns. Moreover, the viability of CuO reactive inks, coupled with the PTP technology and pre ink-drying protocols, has also been demonstrated for the additive integration of a low-cost Cu temperature sensor onto a flexible polymer substrate.« less

  12. Low-Thermal-Budget Photonic Processing of Highly Conductive Cu Interconnects Based on CuO Nanoinks: Potential for Flexible Printed Electronics.

    PubMed

    Rager, Matthew S; Aytug, Tolga; Veith, Gabriel M; Joshi, Pooran

    2016-01-27

    In the developing field of printed electronics, nanoparticle based inks such as CuO show great promise as a low-cost alternative to other metal-based counterparts (e.g., silver). In particular, CuO inks significantly eliminate the issue of particle oxidation before and during the sintering process that is prevalent in Cu-based formulations. We report here the scalable and low-thermal-budget photonic fabrication of Cu interconnects employing a roll-to-roll (R2R)-compatible pulse-thermal-processing (PTP) technique that enables phase reduction and subsequent sintering of ink-jet-printed CuO patterns onto flexible polymer templates. Detailed investigations of curing and sintering conditions were performed to understand the impact of PTP system conditions on the electrical performance of the Cu patterns. Specifically, the impact of energy and power of photonic pulses on print conductivity was systematically studied by varying the following key processing parameters: pulse intensity, duration, and sequence. Through optimization of such parameters, highly conductive prints were obtained in <1 s with resistivity values as low as 10 μΩ cm (corresponding to ∼17% of the International Annealed Copper Standard (IACS) conductivity) was achieved. It was also observed that the introduction of an initial ink-drying step in ambient atmosphere, after the printing and before sintering, leads to significant improvements in mechanical integrity and electrical performance of the printed Cu patterns. Moreover, the viability of CuO reactive inks, coupled with the PTP technology and pre-sintering ink-drying protocols, has also been demonstrated for the additive integration of a low-cost Cu temperature sensor onto a flexible polymer substrate. PMID:26720684

  13. Low thermal budget photonic processing of highly conductive Cu interconnects based on CuO nanoinks. Potential for flexible printed electronics

    SciTech Connect

    Rager, Matthew S.; Aytug, Tolga; Veith, Gabriel M.; Joshi, Pooran C.

    2015-12-31

    The developing field of printed electronics nanoparticle based inks such as CuO show great promise as a low-cost alternative to other metal-based counterparts (e.g., silver). In particular, CuO inks significantly eliminate the issue of particle oxidation, before and during the sintering process, that is prevalent in Cu-based formulations. We report here the scalable and low-thermal budget photonic fabrication of Cu interconnects employing a roll-to-roll compatible pulse-thermal-processing (PTP) technique that enables phase reduction and subsequent sintering of inkjet-printed CuO patterns onto flexible polymer templates. Detailed investigations of curing and sintering conditions were performed to understand the impact of PTP system conditions on the electrical performance of the Cu patterns. Specifically, the impact of energy and power of photonic pulses on print conductivity was systematically studied by varying the following key processing parameters: pulse intensity, duration and sequence. Through optimization of such parameters, highly conductive prints in < 1 s with resistivity values as low as 100 n m has been achieved. We also observed that the introduction of an initial ink-drying step in ambient atmosphere, after the printing and before sintering, leads to significant improvements in mechanical integrity and electrical performance of the printed Cu patterns. Moreover, the viability of CuO reactive inks, coupled with the PTP technology and pre ink-drying protocols, has also been demonstrated for the additive integration of a low-cost Cu temperature sensor onto a flexible polymer substrate.

  14. Low-Thermal-Budget Photonic Processing of Highly Conductive Cu Interconnects Based on CuO Nanoinks: Potential for Flexible Printed Electronics.

    PubMed

    Rager, Matthew S; Aytug, Tolga; Veith, Gabriel M; Joshi, Pooran

    2016-01-27

    In the developing field of printed electronics, nanoparticle based inks such as CuO show great promise as a low-cost alternative to other metal-based counterparts (e.g., silver). In particular, CuO inks significantly eliminate the issue of particle oxidation before and during the sintering process that is prevalent in Cu-based formulations. We report here the scalable and low-thermal-budget photonic fabrication of Cu interconnects employing a roll-to-roll (R2R)-compatible pulse-thermal-processing (PTP) technique that enables phase reduction and subsequent sintering of ink-jet-printed CuO patterns onto flexible polymer templates. Detailed investigations of curing and sintering conditions were performed to understand the impact of PTP system conditions on the electrical performance of the Cu patterns. Specifically, the impact of energy and power of photonic pulses on print conductivity was systematically studied by varying the following key processing parameters: pulse intensity, duration, and sequence. Through optimization of such parameters, highly conductive prints were obtained in <1 s with resistivity values as low as 10 μΩ cm (corresponding to ∼17% of the International Annealed Copper Standard (IACS) conductivity) was achieved. It was also observed that the introduction of an initial ink-drying step in ambient atmosphere, after the printing and before sintering, leads to significant improvements in mechanical integrity and electrical performance of the printed Cu patterns. Moreover, the viability of CuO reactive inks, coupled with the PTP technology and pre-sintering ink-drying protocols, has also been demonstrated for the additive integration of a low-cost Cu temperature sensor onto a flexible polymer substrate.

  15. Polymer Solidification and Stabilization: Adaptable Processes for Atypical Wastes

    SciTech Connect

    Jensen, C.

    2007-07-01

    Vinyl Ester Styrene (VES) and Advanced Polymer Solidification (APS{sup TM}) processes are used to solidify, stabilize, and immobilize radioactive, pyrophoric and hazardous wastes at US Department of Energy (DOE) and Department of Defense (DOD) sites, and commercial nuclear facilities. A wide range of projects have been accomplished, including in situ immobilization of ion exchange resin and carbon filter media in decommissioned submarines; underwater solidification of zirconium and hafnium machining swarf; solidification of uranium chips; impregnation of depth filters; immobilization of mercury, lead and other hazardous wastes (including paint chips and blasting media); and in situ solidification of submerged demineralizers. Discussion of the adaptability of the VES and APS{sup TM} processes is timely, given the decommissioning work at government sites, and efforts by commercial nuclear plants to reduce inventories of one-of-a-kind wastes. The VES and APS{sup TM} media and processes are highly adaptable to a wide range of waste forms, including liquids, slurries, bead and granular media; as well as metal fines, particles and larger pieces. With the ability to solidify/stabilize liquid wastes using high-speed mixing; wet sludges and solids by low-speed mixing; or bead and granular materials through in situ processing, these polymer will produce a stable, rock-hard product that has the ability to sequester many hazardous waste components and create Class B and C stabilized waste forms for disposal. Technical assessment and approval of these solidification processes and final waste forms have been greatly simplified by exhaustive waste form testing, as well as multiple NRC and CRCPD waste form approvals. (authors)

  16. Optimization of a planar all-polymer transistor for characterization of barrier tissue.

    PubMed

    Ramuz, Marc; Margita, Kaleigh; Hama, Adel; Leleux, Pierre; Rivnay, Jonathan; Bazin, Ingrid; Owens, Róisín M

    2015-04-27

    The organic electrochemical transistor (OECT) is a unique device that shows great promise for sensing in biomedical applications such as monitoring of the integrity of epithelial tissue. It is a label-free sensor that is amenable to low-cost production by roll-to-roll or other printing technologies. Herein, the optimization of a planar OECT for the characterization of barrier tissue is presented. Evaluation of surface coating, gate biocompatibility and performance, and optimization of the geometry of the transistor are highlighted. The conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate), which is used as the active material in the transistor, has the added advantage of allowing significant light transmission compared to traditional electrode materials and thus permits high-quality optical microscopy. The combination of optical and electronic monitoring of cells shown herein provides the opportunity to couple two very complementary techniques to yield a low-cost method for in vitro cell sensing.

  17. Optimization of a planar all-polymer transistor for characterization of barrier tissue.

    PubMed

    Ramuz, Marc; Margita, Kaleigh; Hama, Adel; Leleux, Pierre; Rivnay, Jonathan; Bazin, Ingrid; Owens, Róisín M

    2015-04-27

    The organic electrochemical transistor (OECT) is a unique device that shows great promise for sensing in biomedical applications such as monitoring of the integrity of epithelial tissue. It is a label-free sensor that is amenable to low-cost production by roll-to-roll or other printing technologies. Herein, the optimization of a planar OECT for the characterization of barrier tissue is presented. Evaluation of surface coating, gate biocompatibility and performance, and optimization of the geometry of the transistor are highlighted. The conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate), which is used as the active material in the transistor, has the added advantage of allowing significant light transmission compared to traditional electrode materials and thus permits high-quality optical microscopy. The combination of optical and electronic monitoring of cells shown herein provides the opportunity to couple two very complementary techniques to yield a low-cost method for in vitro cell sensing. PMID:25752503

  18. Full-solution processed flexible organic solar cells using low-cost printable copper electrodes.

    PubMed

    Li, Kan; Zhen, Hongyu; Niu, Liyong; Fang, Xu; Zhang, Yaokang; Guo, Ruisheng; Yu, You; Yan, Feng; Li, Haifeng; Zheng, Zijian

    2014-11-12

    Full-solution-processed flexible organic solar cells (OSCs) are fabricated using low-cost and high-quality printable Cu electrodes, which achieve a power conversion efficiency as high as 2.77% and show remarkable stability upon 1000 bending cycles. This device performance is thought to be the best among all full-solution-processed OSCs reported in the literature using the same active materials. This printed Cu electrode is promising for application in roll-to-roll fabrication of flexible OSCs.

  19. Hybrid polymer fabrication process for electro-enzymatic glucose sensor

    NASA Astrophysics Data System (ADS)

    Patel, Jasbir N.; Kaminska, Bozena; Gray, Bonnie L.; Gates, Byron D.

    2008-02-01

    We present a novel self-aligned and hybrid polymer fabrication process for an electro-enzymatic glucose sensor. The self-aligned fabrication process is performed using polydimethylsiloxane (PDMS) as a process substrate material, SU-8 as a sensor structural material, and gold as an electrode material. PDMS has many advantages as a process substrate over conventional substrates such as bare silicon or glass. During the fabrication process, SU-8 has good adhesion to the PDMS. However, after completion of all fabrication steps, the SU-8 based sensors can be easily peeled-off from the PDMS. The PDMS is prepared on a glass handle wafer, and is reusable for many process cycles. Such an SU-8 release technique from a PDMS substrate has never been proposed before. The novel process is employed to realize a glucose sensor with active and reference gold electrodes that are sandwiched between two SU-8 layers with contact pad openings and the active area opening to the top SU-8 layer. The enzyme glucose oxidase is immobilized within the confined active area opening to provide an active electrode sensing surface. After successful fabrication using the hybrid process, the overall thickness of the sensors is measured between 166.15 μm and 210.15 μm. The sensor area and the electrode area are 2mm x 3mm and 2mm x 2mm respectively. The resulting glucose sensors are mechanically flexible. A linear response is observed for the glucose sensors, typically between 50mg/dl and 600mg/dl glucose concentrations.

  20. Electron Beam-Cure Polymer Matrix Composites: Processing and Properties

    NASA Technical Reports Server (NTRS)

    Wrenn, G.; Frame, B.; Jensen, B.; Nettles, A.

    2001-01-01

    Researchers from NASA and Oak Ridge National Laboratory are evaluating a series of electron beam curable composites for application in reusable launch vehicle airframe and propulsion systems. Objectives are to develop electron beam curable composites that are useful at cryogenic to elevated temperatures (-217 C to 200 C), validate key mechanical properties of these composites, and demonstrate cost-saving fabrication methods at the subcomponent level. Electron beam curing of polymer matrix composites is an enabling capability for production of aerospace structures in a non-autoclave process. Payoffs of this technology will be fabrication of composite structures at room temperature, reduced tooling cost and cure time, and improvements in component durability. This presentation covers the results of material property evaluations for electron beam-cured composites made with either unidirectional tape or woven fabric architectures. Resin systems have been evaluated for performance in ambient, cryogenic, and elevated temperature conditions. Results for electron beam composites and similar composites cured in conventional processes are reviewed for comparison. Fabrication demonstrations were also performed for electron beam-cured composite airframe and propulsion piping subcomponents. These parts have been built to validate manufacturing methods with electron beam composite materials, to evaluate electron beam curing processing parameters, and to demonstrate lightweight, low-cost tooling options.

  1. Multiscale metrologies for process optimization of carbon nanotube polymer composites

    DOE PAGES

    Natarajan, Bharath; Orloff, Nathan D.; Ashkar, Rana; Doshi, Sagar; Twedt, Kevin; Krishnamurthy, Ajay; Davis, Chelsea; Forster, Aaron M.; Thostenson, Erik; Obrzut, Jan; et al

    2016-07-18

    Carbon nanotube (CNT) polymer nanocomposites are attractive multifunctional materials with a growing range of commercial applications. With the increasing demand for these materials, it is imperative to develop and validate methods for on-line quality control and process monitoring during production. In this work, a novel combination of characterization techniques is utilized, that facilitates the non-invasive assessment of CNT dispersion in epoxy produced by the scalable process of calendering. First, the structural parameters of these nanocomposites are evaluated across multiple length scales (10-10 m to 10-3 m) using scanning gallium-ion microscopy, transmission electron microscopy and small-angle neutron scattering. Then, a non-contactmore » resonant microwave cavity perturbation (RCP) technique is employed to accurately measure the AC electrical conductivity of the nanocomposites. Quantitative correlations between the conductivity and structural parameters find the RCP measurements to be sensitive to CNT mass fraction, spatial organization and, therefore, the processing parameters. These results, and the non-contact nature and speed of RCP measurements identify this technique as being ideally suited for quality control of CNT nanocomposites in a nanomanufacturing environment. In conclusion, when validated by the multiscale characterization suite, RCP may be broadly applicable in the production of hybrid functional materials, such as graphene, gold nanorod, and carbon black nanocomposites.« less

  2. Processing biobased polymers using plasticizers: Numerical simulations versus experiments

    NASA Astrophysics Data System (ADS)

    Desplentere, Frederik; Cardon, Ludwig; Six, Wim; Erkoç, Mustafa

    2016-03-01

    In polymer processing, the use of biobased products shows lots of possibilities. Considering biobased materials, biodegradability is in most cases the most important issue. Next to this, bio based materials aimed at durable applications, are gaining interest. Within this research, the influence of plasticizers on the processing of the bio based material is investigated. This work is done for an extrusion grade of PLA, Natureworks PLA 2003D. Extrusion through a slit die equipped with pressure sensors is used to compare the experimental pressure values to numerical simulation results. Additional experimental data (temperature and pressure data along the extrusion screw and die are recorded) is generated on a dr. Collin Lab extruder producing a 25mm diameter tube. All these experimental data is used to indicate the appropriate functioning of the numerical simulation tool Virtual Extrusion Laboratory 6.7 for the simulation of both the industrial available extrusion grade PLA and the compound in which 15% of plasticizer is added. Adding the applied plasticizer, resulted in a 40% lower pressure drop over the extrusion die. The combination of different experiments allowed to fit the numerical simulation results closely to the experimental values. Based on this experience, it is shown that numerical simulations also can be used for modified bio based materials if appropriate material and process data are taken into account.

  3. Basic physical and chemical processes in space radiation effects on polymers

    NASA Technical Reports Server (NTRS)

    Kamaratos, E.; Wilson, J. W.; Chang, C. K.; Xu, Y. J.

    1982-01-01

    The effects of space ionizing radiation on polymers is investigated in terms of operative physical and chemical processes. A useful model of charged particle impact with a polymer was designed. Principle paths of molecular relaxation were identified and energy handling processes were considered. The focus of the study was on energy absorption and the immediately following events. Further study of the radiation degradation of polymers is suggested.

  4. Polymers.

    ERIC Educational Resources Information Center

    Tucker, David C.

    1986-01-01

    Presents an open-ended experiment which has students exploring polymer chemistry and reverse osmosis. This activity involves construction of a polymer membrane, use of it in a simple osmosis experiment, and application of its principles in solving a science-technology-society problem. (ML)

  5. Effect of design and process parameters on nip width of soft calendering

    NASA Astrophysics Data System (ADS)

    Kanth, Neel; Ray, A. K.; Dang, Riti

    2016-07-01

    Calendering is a well-known operation in which a material is run between rolls to thin it into sheets or to produce smooth or glossy finish. An attempt has been made in this investigation to remove the drawbacks in the model of Meijers and applicable directly to soft calendering, also to make nip mechanics model generalized and applicable, so that it can be applicable where there is roll to roll or roll to plate contact. Also, the effect of various design and process parameters on results of soft calendering has been discussed using the data taken from paper industry.

  6. Process property studies of melt blown thermoplastic polyurethane polymers

    NASA Astrophysics Data System (ADS)

    Lee, Youn Eung

    The primary goal of this research was to determine optimum processing conditions to produce commercially acceptable melt blown (MB) thermoplastic polyurethane (TPU) webs. The 6-inch MB line and the 20-inch wide Accurate Products MB pilot line at the Textiles and Nonwovens Development Center (TANDEC), The University of Tennessee, Knoxville, were utilized for this study. The MB TPU trials were performed in four different phases: Phase 1 focused on the envelope of the MB operating conditions for different TPU polymers; Phase 2 focused on the production of commercially acceptable MB TPU webs; Phase 3 focused on the optimization of the processing conditions of MB TPU webs, and the determination of the significant relationships between processing parameters and web properties utilizing statistical analyses; Based on the first three phases, a more extensive study of fiber and web formation in the MB TPU process was made and a multi liner regression model for the MB TPU process versus properties was also developed in Phase 4. In conclusion, the basic MB process was fundamentally valid for the MB TPU process; however, the MB process was more complicated for TPU than PP, because web structures and properties of MB TPUs are very sensitive to MB process conditions: Furthermore, different TPU grades responded very differently to MB processing and exhibited different web structure and properties. In Phase 3 and Phase 4, small fiber diameters of less than 5mum were produced from TPU237, TPU245 and TPU280 pellets, and the mechanical strengths of MB TPU webs including the tensile strength, tear strength, abrasion resistance and tensile elongation were notably good. In addition, the statistical model showed useful interaction regarding trends for processing parameters versus properties of MB TPU webs. Die and air temperature showed multicollinearity problems and fiber diameter was notably affected by air flow rate, throughput and die/air temperature. It was also shown that most of

  7. The rheology, degradation, processing, and characterization of renewable resource polymers

    NASA Astrophysics Data System (ADS)

    Conrad, Jason David

    Renewable resource polymers have become an increasingly popular alternative to conventional fossil fuel based polymers over the past couple decades. The push by the government as well as both industrial and consumer markets to go "green" has provided the drive for companies to research and develop new materials that are more environmentally friendly and which are derived from renewable materials. Two polymers that are currently being produced commercially are poly-lactic acid (PLA) and polyhydroxyalkanoate (PHA) copolymers, both of which can be derived from renewable feedstocks and have shown to exhibit similar properties to conventional materials such as polypropylene, polyethylene, polystyrene, and PET. PLA and PHA are being used in many applications including food packaging, disposable cups, grocery bags, and biomedical applications. In this work, we report on the rheological properties of blends of PLA and PHA copolymers. The specific materials used in the study include Natureworks RTM 7000D grade PLA and PHA copolymers of poly(3-hydroxybutyrate-co-3-hydroxyvalerate). Blends ranging from 10 to 50 percent PHA by weight are also examined. Shear and extensional experiments are performed to characterize the flow behavior of the materials in different flow fields. Transient experiments are performed to study the shear rheology over time in order to determine how the viscoelastic properties change under typical processing conditions and understand the thermal degradation behavior of the materials. For the blends, it is determined that increasing the PHA concentration in the blend results in a decrease in viscosity and increase in degradation. Models are fit to the viscosity of the blends using the pure material viscosities in order to be able to predict the behavior at a given blend composition. We also investigate the processability of these materials into films and examine the resultant properties of the cast films. The mechanical and thermal properties of the

  8. Process for removing polymer-forming impurities from naphtha fraction

    DOEpatents

    Kowalczyk, Dennis C.; Bricklemyer, Bruce A.; Svoboda, Joseph J.

    1983-01-01

    Polymer precursor materials are vaporized without polymerization or are removed from a raw naphtha fraction by passing the raw naphtha to a vaporization zone (24) and vaporizing the naphtha in the presence of a wash oil while stripping with hot hydrogen to prevent polymer deposits in the equipment.

  9. Process for removing polymer-forming impurities from naphtha fraction

    DOEpatents

    Kowalczyk, D.C.; Bricklemyer, B.A.; Svoboda, J.J.

    1983-12-27

    Polymer precursor materials are vaporized without polymerization or are removed from a raw naphtha fraction by passing the raw naphtha to a vaporization zone and vaporizing the naphtha in the presence of a wash oil while stripping with hot hydrogen to prevent polymer deposits in the equipment. 2 figs.

  10. Novel ArF photoresist polymer to suppress the roughness formation in plasma etching processes

    NASA Astrophysics Data System (ADS)

    Kato, Keisuke; Yasuda, Atsushi; Maeda, Shin-ichi; Uesugi, Takuji; Okada, Takeru; Wada, Akira; Samukawa, Seiji

    2013-03-01

    The serious problem associated with 193-nm lithography using an ArF photoresist is roughness formation of photoresist polymer during plasma processes. We have previously investigated the mechanism of roughness formation caused by plasma. The main deciding factor for roughness formation is a chemical reaction between photoresist polymer and reactive species from plasma. The lactone group in photoresist polymer is highly chemically reactive, and shrinking the lactone structure enhances the roughness formation. In this paper, on the basis of the mechanism of roughness formation, we propose a novel ArF photoresist polymer. The roughness formation was much more suppressed in the novel photoresist polymer during plasma etching process than in the previous type. In the novel photoresist polymer, chemical reactions were spread evenly on the photoresist film surface by adding the polar structure. As a result, decreases in the lactone group were inhibited, leading to suppressing ArF photoresist roughness.

  11. Particle manipulation through polymer solutions in microfluidic processes

    NASA Astrophysics Data System (ADS)

    Del Giudice, F.; D'Avino, G.; Villone, M. M.; Greco, F.; Maffettone, P. L.

    2015-12-01

    Manipulation of particles suspended in fluids flowing in microfluidic channels is required in a variety of biological, diagnostic and therapeutic applications. For instance, alignment of particles into a tight stream is a necessary step prior to counting, detecting, and sorting. Generally, this task is accomplished by using a Newtonian fluid as suspending medium and by properly fabricating a complex device aimed to displace particle trajectories. In the last years, however, the use of polymeric liquids in microfluidic processes has received a growing interest. Indeed, the addition of a small amount of polymer in a Newtonian suspension flowing in a channel promotes "internal" forces that can be exploited to manipulate the trajectories of suspended particles in simple devices. In this work, we show the possibility to align particles in simple square-shaped microfluidic channels by exploiting viscoelastic forces in flowing suspending liquids. Experiments have been performed to investigate the effect of the channel length, flow rate, confinement ratio (i.e., the ratio between the particle and channel size) and fluid rheology on the particle alignment. Finally, we present experimental results where particle alignment induced by fluid viscoelasticity is combined with magnetophoresis to deflect magnetic beads in a H-shaped channel. High-efficiency separation of magnetic and non-magnetic beads is demonstrated.

  12. Research Update: Large-area deposition, coating, printing, and processing techniques for the upscaling of perovskite solar cell technology

    NASA Astrophysics Data System (ADS)

    Razza, Stefano; Castro-Hermosa, Sergio; Di Carlo, Aldo; Brown, Thomas M.

    2016-09-01

    To bring perovskite solar cells to the industrial world, performance must be maintained at the photovoltaic module scale. Here we present large-area manufacturing and processing options applicable to large-area cells and modules. Printing and coating techniques, such as blade coating, slot-die coating, spray coating, screen printing, inkjet printing, and gravure printing (as alternatives to spin coating), as well as vacuum or vapor based deposition and laser patterning techniques are being developed for an effective scale-up of the technology. The latter also enables the manufacture of solar modules on flexible substrates, an option beneficial for many applications and for roll-to-roll production.

  13. Preparation of Soy Polymers by a Green Processing Method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ring opening polymerization of epoxidized soybean oil (ESO) initiated by boron trifluoride diethyl etherate was conducted in liquid carbon dioxide. The resulting polymers (RPESO) were characterized using Infrared (IR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), 1H NM...

  14. Dry powder process for preparing uni-tape prepreg from polymer powder coated filamentary towpregs

    NASA Technical Reports Server (NTRS)

    Wilkinson, Steven P. (Inventor); Johnston, Norman J. (Inventor); Marchello, Joseph M. (Inventor)

    1997-01-01

    A process for preparing uni-tape prepreg from polymer powder coated filamentary towpregs is provided. A plurality of polymer powder coated filamentary towpregs are provided. The towpregs are collimated so that each towpreg is parallel. A material is applied to each side of the towpreg to form a sandwich. The sandwich is heated to a temperature wherein the polymer flows and intimately contacts the filaments and pressure is repeatedly applied perpendicularly to the sandwich with a longitudinal oscillating action wherein the filaments move apart and the polymer wets the filaments forming a uni-tape prepreg. The uni-tape prepreg is subsequently cooled.

  15. A Dry Powder Process for Preparing Uni-Tape Prepreg from Polymer Powder Coated Filamentary Towpregs

    NASA Technical Reports Server (NTRS)

    Wilkinson, Steven P. (Inventor); Johnston, Norman J. (Inventor); Marchello, Joseph M. (Inventor)

    1995-01-01

    A process for preparing uni-tape prepreg from polymer powder coated filamentary towpregs is provided. A plurality of polymer powder coated filamentary towpregs are provided. The towpregs are collimated so that each towpreg is parallel. The sandwich is heated to a temperature wherein the polymer flows and intimately contacts the filaments and pressure is repeatedly applied perpendicularly to the sandwich with a longitudinal oscillating action wherein the filaments move apart and the polymer wets the filaments forming a uni-tape prepreg. The uni-tape prepreg is subsequently cooled.

  16. Self-aligned, full solution process polymer field-effect transistor on flexible substrates

    PubMed Central

    Yan, Yan; Huang, Long-Biao; Zhou, Ye; Han, Su-Ting; Zhou, Li; Zhuang, Jiaqing; Xu, Zong-Xiang; Roy, V. A. L.

    2015-01-01

    Conventional techniques to form selective surface energy regions on rigid inorganic substrates are not suitable for polymer interfaces due to sensitive and soft limitation of intrinsic polymer properties. Therefore, there is a strong demand for finding a novel and compatible method for polymeric surface energy modification. Here, by employing the confined photo-catalytic oxidation method, we successfully demonstrate full polymer filed-effect transistors fabricated through four-step spin-coating process on a flexible polymer substrate. The approach shows negligible etching effect on polymeric film. Even more, the insulating property of polymeric dielectric is not affected by the method, which is vital for polymer electronics. Finally, the self-aligned full polymer field-effect transistors on the flexible polymeric substrate are fabricated, showing good electrical properties and mechanical flexibility under bending tests. PMID:26497412

  17. Processing of Fine-Scale Piezoelectric Ceramic/Polymer Composites for Sensors and Actuators

    NASA Technical Reports Server (NTRS)

    Janas, V. F.; Safari, A.

    1996-01-01

    The objective of the research effort at Rutgers is the development of lead zirconate titanate (PZT) ceramic/polymer composites with different designs for transducer applications including hydrophones, biomedical imaging, non-destructive testing, and air imaging. In this review, methods for processing both large area and multifunctional ceramic/polymer composites for acoustic transducers were discussed.

  18. Method of solution preparation of polyolefin class polymers for electrospinning processing included

    NASA Technical Reports Server (NTRS)

    Rabolt, John F. (Inventor); Lee, Keun-Hyung (Inventor); Givens, Steven R. (Inventor)

    2011-01-01

    A process to make a polyolefin fiber which has the following steps: mixing at least one polyolefin into a solution at room temperature or a slightly elevated temperature to form a polymer solution and electrospinning at room temperature said polymer solution to form a fiber.

  19. Boron-carbon-silicon polymers and ceramic and a process for the production thereof

    NASA Technical Reports Server (NTRS)

    Riccitiello, Salvatore (Inventor); Hsu, Ming-Ta (Inventor); Chen, Timothy S. (Inventor)

    1992-01-01

    The present invention relates to a process for the production of an organoborosilicon preceramic polymer. The polymer is prepared by the reaction of vinylsilane or vinlymethylsilanes (acetylene)silane or acetylene alkyl silanes and borane or borane derivatives. The prepolymer form is pyrolyzed to produce a ceramic article useful in high temperature (e.g., aerospace) or extreme environmental applications.

  20. Thermal analysis and evolution of shape loss phenomena during polymer burnout in powder metal processing

    NASA Astrophysics Data System (ADS)

    Enneti, Ravi Kumar

    2005-07-01

    Powder metallurgy technology involves manufacturing of net shape or near net shape components starting from metal powders. Polymers are used to provide lubrication during shaping and handling strength to the shaped component. After shaping, the polymers are removed from the shaped components by providing thermal energy to burnout the polymers. Polymer burnout is one of the most critical step in powder metal processing. Improper design of the polymer burnout cycle will result in formation of defects, shape loss, or carbon contamination of the components. The effect of metal particles on polymer burnout and shape loss were addressed in the present research. The study addressing the effect of metal powders on polymer burnout was based on the hypothesis that metal powders act to catalyze polymer burnout. Thermogravimetric analysis (TGA) on pure polymer, ethylene vinyl acetate (EVA), and on admixed powders of 316L stainless steel and 1 wt. % EVA were carried out to verify the hypothesis. The effect of metal powders additions was studied by monitoring the onset temperature for polymer degradation and the temperature at which maximum rate of weight loss occurred from the TGA data. The catalytic behavior of the powders was verified by varying the particle size and shape of the 316L stainless powder. The addition of metal particles lowered the polymer burnout temperatures. The onset temperature for burnout was found to be sensitive to the surface area of the metal particle as well as the polymer distribution. Powders with low surface area and uniform distribution of polymer showed a lower burnout temperature. The evolution of shape loss during polymer burnout was based on the hypothesis that shape loss occurs during the softening of the polymer and depends on the sequence of chemical bonding in the polymer during burnout. In situ observation of shape loss was carried out on thin beams compacted from admixed powders of 316L stainless steel and 1 wt. % ethylene vinyl acetate

  1. Removal and recovery of metal ions from process and waste streams using polymer filtration

    SciTech Connect

    Jarvinen, G.D.; Smith, B.F.; Robison, T.W.; Kraus, K.M.; Thompson, J.A.

    1999-06-13

    Polymer Filtration (PF) is an innovative, selective metal removal technology. Chelating, water-soluble polymers are used to selectively bind the desired metal ions and ultrafiltration is used to concentrate the polymer-metal complex producing a permeate with low levels of the targeted metal ion. When applied to the treatment of industrial metal-bearing aqueous process streams, the permeate water can often be reused within the process and the metal ions reclaimed. This technology is applicable to many types of industrial aqueous streams with widely varying chemistries. Application of PF to aqueous streams from nuclear materials processing and electroplating operations will be described.

  2. Polymer Based Nanocomposites for Solar Energy Conversion

    SciTech Connect

    Shaheen, S.; Olson, D.; White, M.; Mitchell, W.; Miedaner, A.; Curtis, C.; Rumbles, G.; Gregg, B.; Ginley, D.

    2005-01-01

    Organic semiconductor-based photovoltaic devices offer the promise of low cost photovoltaic technology that can be manufactured via large-scale, roll-to-roll printing techniques. Existing organic photovoltaic devices are currently limited to solar power conversion efficiencies of 3?5%. This is because of poor overlap between the absorption spectrum of the organic chromophores and the solar spectrum, non-ideal band alignment between the donor and acceptor species, and low charge carrier mobilities. To address these issues, we are investigating the development of dendrimeric organic semiconductors that are readily synthesized with high purity. They also benefit from optoelectronic properties, such as band gap and band positions, which can be easily tuned by substituting different chemical groups into the molecule. Additionally, we are developing nanostructured oxide/conjugated polymer composite photovoltaics. These composites take advantage of the high electron mobilities attainable in oxide semiconductors and can be fabricated using low-temperature solution-based growth techniques. Here, we discuss the synthesis and preliminary device results of these novel materials and composites.

  3. Process for crosslinking methylene-containing aromatic polymers with ionizing radiation

    NASA Technical Reports Server (NTRS)

    Bell, Vernon L. (Inventor); Havens, Stephen J. (Inventor)

    1990-01-01

    A process for crosslinking aromatic polymers containing radiation-sensitive methylene groups (-CH2-) by exposing the polymers to ionizing radiation thereby causing crosslinking of the polymers through the methylene groups is described. Crosslinked polymers are resistant to most organic solvents such as acetone, alcohols, hydrocarbons, methylene, chloride, chloroform, and other halogenated hydrocarbons, to common fuels and to hydraulic fluids in contrast to readily soluble uncrosslinked polymers. In addition, the degree of crosslinking of the polymers depends upon the percentage of the connecting groups which are methylene which ranges from 5 to 50 pct and preferably from 25 to 50 pct of the connecting groups, and is also controlled by the level of irradiation which ranges from 25 to 1000 Mrads and preferably from 25 to 250 Mrads. The temperature of the reaction conditions ranges from 25 to 200 C and preferably at or slightly above the glass transition temperature of the polymer. The crosslinked polymers are generally more resistant to degradation at elevated temperatures such as greater than 150 C, have a reduced tendency to creep under load, and show no significant embrittlement of parts fabricated from the polymers.

  4. STIMULI-RESPONSIVE POLYMERS WITH ENHANCED EFFICIENCY IN RESERVOIR RECOVERY PROCESSES

    SciTech Connect

    Charles McCormick; Roger Hester

    2004-09-30

    This sixth and final progress report for DOE Award Number DE-FC26-01BC15317 describes research during the period March 01, 2004 through August 31, 2004 performed at the University of Southern Mississippi on ''Stimuli Responsive Polymers with Enhanced Efficiency in Reservoir Recovery'' processes. Significantly, terpolymers that are responsive to changes in pH and ionic strength have been synthesized, characterized, and their solution properties have been extensively examined. Terpolymers composed of acrylamide, a carboxylated acrylamido monomer (AMBA), and a quaternary ammonium monomer (AMBATAC) with balanced compositions of the latter two, exhibit increases in aqueous solution viscosity as NaCl concentration is increased. This increase in polymer coil size can be expected upon injection of this type of polymer into oil reservoirs of moderate-to-high salinity, leading to better mobility control. The opposite effect (loss of viscosity) is observed for conventional polymer systems. Additionally polymer mobility characteristics have been conducted for a number of hydrophilic copolymers utilizing an extensional flow apparatus and size exclusion chromatography. This study reveled that oil recovery enhancement through use of polymers in a water flood is due to the polymer's resistance to deformation as it flows through the reservoir. Individual polymers when in aqueous solution form coils. The larger the polymer's coil size, the greater the polymer's resistance to extensional flow and the more effective the polymer is in enhancing oil recovery. Large coil sizes are obtained by increasing the polymer molecular weight and having macromolecular structures that favor greater swelling of the coil by the aqueous solvent conditions (temperature, pH and electrolyte concentration) existing in the reservoir.

  5. Polymer and protein interfacial competition in a shell production process

    NASA Astrophysics Data System (ADS)

    Willard, Emma; Randall, Greg

    2015-11-01

    We are exploring oil-in-aqueous polymer compound droplet formulations to UV polymerize into shells while in a strong AC electric field (kV/cm, 20 MHz). The electric field drives the drops to adopt a concentric configuration so that a ``perfect'' spherical shell can be polymerized with a uniform wall thickness. In our previous study of oil-in-water droplet centering, we determined that droplet stretching in the electric field was a problem, which we overcame by using protein additives to strengthen the oil/water interface. However, adding polymer to the shell fluid has been shown to weaken the droplet interface and further complicates T junction droplet generation. In this work, we study the adsorption competition between bovine serum albumin and polyethylene glycol diacrylate with the pendant drop method to generate a polymer/protein shell formulation that will resist stretching in the centering electric field. Furthermore, we explore droplet generation of polymer/protein shell formulations in a double T junction and stretching in an electric field. Work supported by General Atomics IR&D funds.

  6. Aqueous-Processed Insulating Polymer/Nanocrystal Hybrid Solar Cells.

    PubMed

    Jin, Gan; Chen, Zhaolai; Dong, Chunwei; Cheng, Zhongkai; Du, Xiaohang; Zeng, Qingsen; Liu, Fangyuan; Sun, Haizhu; Zhang, Hao; Yang, Bai

    2016-03-23

    A novel kind of hybrid solar cell (HSC) was developed by introducing water-soluble insulating polymer poly(vinyl alcohol) (PVA) into nanocrystals (NCs), which revealed that the most frequently used conjugated polymer could be replaced by an insulating one. It was realized by strategically taking advantage of the characteristic of decomposition for the polymer at annealing temperature, and it was interesting to discover that partial decomposition of PVA left behind plenty of pits on the surfaces of CdTe NC films, enlarging surface contact area between CdTe NCs and subsequently evaporated MoO3. Moreover, the residual annealed PVA filled in the voids among spherical CdTe NCs, which led to the decrease of leakage current. An improved shunt resistance (increased by ∼80%) was achieved, indicating the charge-carrier recombination was effectively overcome. As a result, the new HSCs were endowed with increased Voc, fill factor, and power conversion efficiency compared with the pure NC device. This approach can be applied to other insulating polymers (e.g., PVP) with advantages in synthesis, type, economy, stability, and so on, providing a novel universal cost-effective way to achieve higher photovoltaic performance.

  7. Aqueous-Processed Insulating Polymer/Nanocrystal Hybrid Solar Cells.

    PubMed

    Jin, Gan; Chen, Zhaolai; Dong, Chunwei; Cheng, Zhongkai; Du, Xiaohang; Zeng, Qingsen; Liu, Fangyuan; Sun, Haizhu; Zhang, Hao; Yang, Bai

    2016-03-23

    A novel kind of hybrid solar cell (HSC) was developed by introducing water-soluble insulating polymer poly(vinyl alcohol) (PVA) into nanocrystals (NCs), which revealed that the most frequently used conjugated polymer could be replaced by an insulating one. It was realized by strategically taking advantage of the characteristic of decomposition for the polymer at annealing temperature, and it was interesting to discover that partial decomposition of PVA left behind plenty of pits on the surfaces of CdTe NC films, enlarging surface contact area between CdTe NCs and subsequently evaporated MoO3. Moreover, the residual annealed PVA filled in the voids among spherical CdTe NCs, which led to the decrease of leakage current. An improved shunt resistance (increased by ∼80%) was achieved, indicating the charge-carrier recombination was effectively overcome. As a result, the new HSCs were endowed with increased Voc, fill factor, and power conversion efficiency compared with the pure NC device. This approach can be applied to other insulating polymers (e.g., PVP) with advantages in synthesis, type, economy, stability, and so on, providing a novel universal cost-effective way to achieve higher photovoltaic performance. PMID:26931540

  8. Understanding the transport processes in polymer electrolyte membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Cheah, May Jean

    Polymer electrolyte membrane (PEM) fuel cells are energy conversion devices suitable for automotive, stationary and portable applications. An engineering challenge that is hindering the widespread use of PEM fuel cells is the water management issue, where either a lack of water (resulting in membrane dehydration) or an excess accumulation of liquid water (resulting in fuel cell flooding) critically reduces the PEM fuel cell performance. The water management issue is addressed by this dissertation through the study of three transport processes occurring in PEM fuel cells. Water transport within the membrane is a combination of water diffusion down the water activity gradient and the dragging of water molecules by protons when there is a proton current, in a phenomenon termed electro-osmotic drag, EOD. The impact of water diffusion and EOD on the water flux across the membrane is reduced due to water transport resistance at the vapor/membrane interface. The redistribution of water inside the membrane by EOD causes an overall increase in the membrane resistance that regulates the current and thus EOD, thereby preventing membrane dehydration. Liquid water transport in the PEM fuel cell flow channel was examined at different gas flow regimes. At low gas Reynolds numbers, drops transitioned into slugs that are subsequently pushed out of the flow channel by the gas flow. The slug volume is dependent on the geometric shape, the surface wettability and the orientation (with respect to gravity) of the flow channel. The differential pressure required for slug motion primarily depends on the interfacial forces acting along the contact lines at the front and the back of the slug. At high gas Reynolds number, water is removed as a film or as drops depending on the flow channel surface wettability. The shape of growing drops at low and high Reynolds number can be described by a simple interfacial energy minimization model. Under flooding conditions, the fuel cell local current

  9. Morphology evolution in high-performance polymer solar cells processed from nonhalogenated solvent

    DOE PAGES

    Cai, Wanzhu; Liu, Peng; Jin, Yaocheng; Xue, Qifan; Liu, Feng; Russell, Thomas P.; Huang, Fei; Yip, Hin -Lap; Cao, Yong

    2015-05-26

    A new processing protocol based on non-halogenated solvent and additive is developed to produce polymer solar cells with power conversion efficiencies better than those processed from commonly used halogenated solvent-additive pair. Morphology studies show that good performance correlates with a finely distributed nanomorphology with a well-defined polymer fibril network structure, which leads to balanced charge transport in device operation.

  10. Thermally Activated Delayed Fluorescence Polymers for Efficient Solution-Processed Organic Light-Emitting Diodes.

    PubMed

    Lee, Sae Youn; Yasuda, Takuma; Komiyama, Hideaki; Lee, Jiyoung; Adachi, Chihaya

    2016-06-01

    Thermally activated delayed fluorescence (TADF) π-conjugated polymers are developed for solution-processed TADF-OLEDs. Benzophenone-based alternating donor-acceptor structures contribute to the small ∆EST , enabling efficient exciton-harvesting through TADF. Solution-processed OLEDs using the TADF polymers as emitters can achieve high maximum external electroluminescence efficiencies of up to 9.3%. PMID:27001891

  11. Three-dimensional printing of conducting polymer microstructures into transparent polymer sheet: Relationship between process resolution and illumination conditions

    NASA Astrophysics Data System (ADS)

    Yamada, Katsumi; Watanabe, Mizuki; Sone, Junji

    2014-09-01

    Three-dimensional (3D) polypyrrole microstructures were successfully obtained in a transparent polymer sheet by 3D scanning of the laser focal point. The lateral process resolution of the microstructures was studied under different photofabrication conditions such as the repetition rate of the femtosecond pulse laser and the waiting time of the laser focal point scanning. As a result, a very small line width of the polypyrrole deposition of less than 500 nm was realized with good reproducibility.

  12. A Process for Preparing 1,3-Diamino-5-Pentafluorosulfanylbenzene and Polymers Therefrom

    NASA Technical Reports Server (NTRS)

    St.clair, Anne K. (Inventor); St.clair, Terry L. (Inventor); Thrasher, Joseph S. (Inventor)

    1991-01-01

    Diamines have shown their utility in the formation of many polymers. Examples of these polymers include polyimides, polyamides, and epoxies. The properties of these polymers are often dependent on the diamine which is used to make the polymer. By the present invention, a process was developed to make a diamine containing pentafluorosulfanylbenzene moiety. This process involves two steps: the preparation of a dinitro precursor and the reduction of the dinitro compound to form the diamine. This diamine was then reacted with various dianhydrides, diacidchlorides, and epoxy resins to yield the corresponding polyimide, polyamide, and epoxy polymers. These polymers were then used to make films, a wire coating enamel, and a semi-permeable membrane. The novelty of this invention resides in the process to make the diamine. Traditionally, dinitro compounds are reduced with hydrazine or a catalyst such as palladium on charcoal. The catalyst which is used in this invention is platinum oxide. When this catalyst is used, it makes it possible to form a polymer-grade diamine.

  13. Understanding the impact of polymer self-organization on the microstructure and charge transport in poly(3-hexylthiophene)

    NASA Astrophysics Data System (ADS)

    Aiyar, Avishek R.

    Conjugated polymers represent the next generation of conducting materials that will enable technological devices incorporating thin film transistors, photovoltaic (PV) cells etc. in a cost effective roll-to-roll manner. The charge carrier mobility, which characterizes the ease with which charges can be transported through the material, is the key metric by which these materials are gaged and is also a decisive factor that limits device performance. Given the impact of microstructure on charge transport, ordered self-assembly in polymeric semiconductors assumes paramount relevance. This thesis outlines a fundamental investigation of the correlations between the morphology and microstructure of a model conjugated polymer, poly(3-hexylthiophene) (P3HT), and its corresponding charge transport properties in an organic field effect transistor (OFET) geometry. Moreover, the evolution of the structural and electrical properties are mapped, which provide new insights into the self-assembly process. The variation in the electrical properties is studied as film formation evolves as a function of solvent evaporation from a sessile P3HT solution droplet. The channel formation process is mapped using four contact field effect measurements. The channel formation study is complimented by interrogating the evolution of the polymer chain conformations using in situ Raman spectroscopy, which reveals the presence of an intermediate lyotropic liquid crystalline phase before film crystallization. The manifestation of the liquid crystalline phase offers a potential rationale to the mobility profiles recorded by the in situ electrical measurements. A joint investigation of both measurements reveals that the onset of channel current occurs well before polymer crystallization and that the subtle structural changes in the P3HT film continue to evolve even after crystallization, which further impact the observed drain current. The large impact of polymer chain conformations on the drain

  14. Hybrid light emitting diodes based on solution processed polymers, colloidal quantum dots, and colloidal metal nanoparticles

    NASA Astrophysics Data System (ADS)

    Ma, Xin

    This dissertation focuses on solution-processed light-emitting devices based on polymer, polymer/PbS quantum dot, and polymer/silver nanoparticle hybrid materials. Solution based materials and organic/inorganic hybrid light emitting diodes attracted significant interest recently due to many of their advantages over conventional light emitting diodes (LEDs) including low fabrication cost, flexible, high substrate compatibility, as well as tunable emission wavelength of the quantum dot materials. However, the application of these novel solution processed materials based devices is still limited due to their low performances. Material properties and fabrication parameters need to be carefully examined and understood for further device improvement. This thesis first investigates the impact of solvent property and evaporation rate on the polymer molecular chain morphology and packaging in device structures. Solvent is a key component to make the active material solution for spin coating fabrication process. Their impacts are observed and examined on both polymer blend system and mono-polymer device. Secondly, PbS colloidal quantum dot are introduced to form hybrid device with polymer and to migrate the device emission into near-IR range. As we show, the dithiol molecules used to cross-link quantum dots determine the optical and electrical property of the resulting thin films. By choosing a proper ligand for quantum dot ligand exchange, a high performance polymer/quantum dot hybrid LED is fabricated. In the end, the interaction of polymer exciton with surface plasmon mode in colloidal silver nanoparticles and the use of this effect to enhance solution processed LEDs' performances are investigated.

  15. Process for preparing phthalocyanine polymer from imide containing bisphthalonitrile

    NASA Technical Reports Server (NTRS)

    Achar, Bappalige N. (Inventor); Fohlen, George M. (Inventor); Parker, John A. (Inventor)

    1987-01-01

    Imide-linked bisphthalonitrile compounds are prepared by combining a dicyano aromatic diamine and an organic dianhydride to produce an amic acid linked bisphthalonitrile compound. The amic acid linked bisphthalonitrile compound is dehydrocyclized to produce the imide-linked bisphthalonitrile compounds. The imide-linked bisphthalonitrile compounds may be polymerized to produce a phythalocyanine polymer by heating the imide-linked bisphthalonitrile compound, either alone or in the presence of a metal powder or a metal salt. These compounds are useful in the coating, laminating and molding arts. The polymers are useful in composite matrix resins where increased fire resistance, toughness and resistance to moisture are required, particularly as secondary structures in aircraft and spacecraft.

  16. Organic Polymer Chemistry in the Context of Novel Processes

    PubMed Central

    2016-01-01

    This article was written to shed light on a series of what some have stated are not so obvious connections that link polymer synthesis in supercritical CO2 to cancer treatment and vaccines, nonflammable polymer electrolytes for lithium ion batteries, and 3D printing. In telling this story, we also attempt to show the value of versatility in applying one’s primary area of expertise to address pertinent questions in science and in society. In this Outlook, we attempted to identify key factors to enable a versatile and nimble research effort to take shape in an effort to influence diverse fields and have a tangible impact in the private sector through the translation of discoveries into the marketplace. PMID:27725955

  17. Processing of Polymer Nanofibers Through Electrospinning as Drug Delivery Systems

    NASA Astrophysics Data System (ADS)

    Kenawy, E.; Abdel-Hay, F. I.; El-Newehy, M. H.; Wnek, G. E.

    The use of electrospun fibers as drug carriers could be promising in the future for biomedical applications, especially postoperative local chemotherapy. In this research, electrospun fibers were developed as a new system for the delivery of ketoprofen as non-steroidal anti-inflammatory drug (NSAID). The fibers were made either from polycaprolactone (PCL) as a biodegradable polymer or polyurethane (PU) as a non-biodegradable polymer, or from the blends of the two. The release of the ketoprofen was followed by UV—VIS spectroscopy in phosphate buffer of pH 7.4 at 37°C and 20°C. The results showed that the release rates from the polycaprolactone, polyurethane and their blend were similar. However, the blend of the polycaprolactone with polyurethane improved its visual mechanical properties. Release profiles from the electrospun mats were compared to cast films of the various formulations.

  18. Chemistry of crosslinking processes for self-healing polymers.

    PubMed

    Billiet, Stijn; Hillewaere, Xander K D; Teixeira, Roberto F A; Du Prez, Filip E

    2013-02-25

    Recent developments in material design have seen an exponential increase of polymers and polymer composites that can repair themselves in response to damage. In this review, a distinction is made between extrinsic materials, where the self-healing property is obtained by adding healing agents to the material to be repaired, and intrinsic materials, where self-healing is achieved by the material itself through its chemical nature. An overview of the crosslinking chemistries used in self-healing materials will be given, discussing the advantages and drawbacks of each system. The review is not only aiming to enable researchers to compare their ongoing research with the state-of-the-art but also to serve as a guide for the newcomers, which allows for a selection of the most promising self-healing chemistries.

  19. Watching the Annealing Process One Polymer Chain at a Time

    SciTech Connect

    Vogelsang, Jan; Brazard, Johanna; Adachi, Takuji; Bolinger, Joshua; Barbara, Paul F.

    2011-02-03

    By using single-molecule spectroscopy (SMS) several effects of solvent vapor induced annealing (SVA) were studied directly on single conjugated polymers, e.g.: SVA-induced translocations, folding/unfolding dynamics, and changes in the morphological order. It is shown that single chains can be trapped by spin-coating in a disordered conformation and subsequent SVA leads to an equilibrated, highly ordered conformation.

  20. Polymer opto-chemical-electronic based module as a detection system for volatile analytes on a foil substrate

    NASA Astrophysics Data System (ADS)

    Bose, Indranil; Ohlander, Anna; Stich, Matthias I. J.; Kiesl, Christian; Hemmetzberger, Dieter; Klink, Gerhard; Trupp, Sabine; Bock, Karlheinz

    2012-10-01

    In this paper, we report on a novel device that addresses the needs for an efficient, field deployable and disposable system in the field of bio-chemical sensors using organic semiconductors. The Fraunhofer Institute has enabled a complete roll-to-roll manufactured polymer-opto-chemical-electronic module on a foil substrate, wherein an electroluminescent light source has been hetero-integrated together with an organic TFT, working as a photo detector. A chemically sensitive, colour changing film is sandwiched in between the two elements to form an optical detection system for volatile analytes such as amines. The setup, henceforth referred to as the "PolyOpto" module, comprises of a dye coated layer that can detect specific chemical reactions by colour change inserted in between the EL light source and the OTFT photo-detector. A hole is laser cut through the system to allow the sensor layer to come in contact with the gases, which then through a chemical reaction, changes colour and initiates a different response in the output of the organic transistor. Hence, this allows for a disposable chemo-analytical system that can be used in various application fields. As compared to conventional systems, the advantage here lies in the direct integration of the different functionalities without any advanced assembly steps, simultaneous use of coatings for both components (transparent electrode and wiring layer) and roll-to-roll compatibility, thus rendering a disposable system. We believe that it aptly demonstrates the capabilities of polytronics in functional integration for low-cost bio-sensor manufacturing.

  1. Processing and characterization of natural cellulose fibers/thermoset polymer composites.

    PubMed

    Thakur, Vijay Kumar; Thakur, Manju Kumari

    2014-08-30

    Recently natural cellulose fibers from different biorenewable resources have attracted the considerable attraction of research community all around the globe owing to their unique intrinsic properties such as biodegradability, easy availability, environmental friendliness, flexibility, easy processing and impressive physico-mechanical properties. Natural cellulose fibers based materials are finding their applications in a number of fields ranging from automotive to biomedical. Natural cellulose fibers have been frequently used as the reinforcement component in polymers to add the specific properties in the final product. A variety of cellulose fibers based polymer composite materials have been developed using various synthetic strategies. Seeing the immense advantages of cellulose fibers, in this article we discuss the processing of biorenewable natural cellulose fibers; chemical functionalization of cellulose fibers; synthesis of polymer resins; different strategies to prepare cellulose based green polymer composites, and diverse applications of natural cellulose fibers/polymer composite materials. The article provides an in depth analysis and comprehensive knowledge to the beginners in the field of natural cellulose fibers/polymer composites. The prime aim of this review article is to demonstrate the recent development and emerging applications of natural cellulose fibers and their polymer materials.

  2. Manufacturing polymer/carbon nanotube composite using a novel direct process.

    PubMed

    Tran, C-D; Lucas, S; Phillips, D G; Randeniya, L K; Baughman, R H; Tran-Cong, T

    2011-04-01

    A direct process for manufacturing polymer carbon nanotube (CNT)-based composite yarns is reported. The new approach is based on a modified dry spinning method of CNT yarn and gives a high alignment of the CNT bundle structure in yarns. The aligned CNT structure was combined with a polymer resin and, after being stressed through the spinning process, the resin was cured and polymerized, with the CNT structure acting as reinforcement in the composite. Thus the present method obviates the need for special and complex treatments to align and disperse CNTs in a polymer matrix. The new process allows us to produce a polymer/CNT composite with properties that may satisfy various engineering specifications. The structure of the yarn was investigated using scanning electron microscopy coupled with a focused-ion-beam system. The tensile behavior was characterized using a dynamic mechanical analyzer. Fourier transform infrared spectrometry was also used to chemically analyze the presence of polymer on the composites. The process allows development of polymer/CNT-based composites with different mechanical properties suitable for a range of applications by using various resins. PMID:21346301

  3. Manufacturing polymer/carbon nanotube composite using a novel direct process.

    PubMed

    Tran, C-D; Lucas, S; Phillips, D G; Randeniya, L K; Baughman, R H; Tran-Cong, T

    2011-04-01

    A direct process for manufacturing polymer carbon nanotube (CNT)-based composite yarns is reported. The new approach is based on a modified dry spinning method of CNT yarn and gives a high alignment of the CNT bundle structure in yarns. The aligned CNT structure was combined with a polymer resin and, after being stressed through the spinning process, the resin was cured and polymerized, with the CNT structure acting as reinforcement in the composite. Thus the present method obviates the need for special and complex treatments to align and disperse CNTs in a polymer matrix. The new process allows us to produce a polymer/CNT composite with properties that may satisfy various engineering specifications. The structure of the yarn was investigated using scanning electron microscopy coupled with a focused-ion-beam system. The tensile behavior was characterized using a dynamic mechanical analyzer. Fourier transform infrared spectrometry was also used to chemically analyze the presence of polymer on the composites. The process allows development of polymer/CNT-based composites with different mechanical properties suitable for a range of applications by using various resins.

  4. Basalt fiber reinforced polymer composites: Processing and properties

    NASA Astrophysics Data System (ADS)

    Liu, Qiang

    A high efficiency rig was designed and built for in-plane permeability measurement of fabric materials. A new data derivation procedure to acquire the flow fluid pattern in the experiment was developed. The measurement results of the in-plane permeability for basalt twill 31 fabric material showed that a high correlation exists between the two principal permeability values for this fabric at 35% fiber volume fraction. This may be the most important scientific contribution made in this thesis. The results from radial measurements corresponded quite well with those from Unidirectional (UD) measurements, which is a well-established technique. No significant differences in mechanical properties were found between basalt fabric reinforced polymer composites and glass composites reinforced by a fabric of similar weave pattern. Aging results indicate that the interfacial region in basalt composites may be more vulnerable to environmental damage than that in glass composites. However, the basalt/epoxy interface may have been more durable than the glass/epoxy interface in tension-tension fatigue because the basalt composites have significantly longer fatigue life. In this thesis, chapter I reviews the literature on fiber reinforced polymer composites, with concentration on permeability measurement, mechanical properties and durability. Chapter II discusses the design of the new rig for in-plane permeability measurement, the new derivation procedure for monitoring of the fluid flow pattern, and the permeability measurement results. Chapter III compares the mechanical properties and durability between basalt fiber and glass fiber reinforced polymer composites. Lastly, chapter IV gives some suggestions and recommendations for future work.

  5. Polymer laser fabricated by a simple micromolding process

    NASA Astrophysics Data System (ADS)

    Lawrence, Justin R.; Turnbull, Graham A.; Samuel, Ifor D. W.

    2003-06-01

    We report polymer distributed feedback lasers fabricated using solvent-assisted microcontact molding. The poly[2-methoxy-5-(3,7-dimethyloctyloxy) paraphenylenevinylene] film is patterned by placing it in conformal contact with an elastomeric mould inked with a suitable solvent. When the resulting microstructured film is pumped with the 532 nm pulsed output of a microchip laser, we observe lasing above a threshold pump energy of 225 nJ. Above threshold the emission narrows to a linewidth of less than 0.6 nm at a wavelength of 638 nm. This micromolding technique may find application to a wide range of wavelength-scale microstructured organic photonic devices.

  6. Electric field-mediated processing of polymer blend solutions

    NASA Technical Reports Server (NTRS)

    Wnek, G. E.; Krause, S.

    1993-01-01

    Multiphase polymer blends in which the minor phases are oriented in a desired direction may demonstrate unique optical, electrical, and mechanical properties. While morphology development in shear fields was studied extensively, little work has focused on effects of electric fields on phase structure. The use of electric fields for blend morphology modulation with particular attention given to solvent casting of blends in d.c. fields was explored. Both homopolymer blends (average phase sizes of several microns) and diblock copolymer/homopolymer blends (average phase sizes of hundreds of Angstroms) were investigated. Summarized are important observations and conclusions.

  7. Functionalization of polymer powders for SLS-processes using an atmospheric plasma jet in a fluidized bed reactor

    SciTech Connect

    Sachs, Marius; Schmitt, Adeliene; Schmidt, Jochen; Peukert, Wolfgang; Wirth, Karl-Ernst

    2015-05-22

    Recently additive manufacturing processes such as selective laser sintering (SLS) of polymers have gained more importance for industrial applications [1]. Tailor-made modification of polymers is essential in order to make these processes more efficient and to cover the industrial demands. The so far used polymer materials show weak performance regarding the mechanical stability of processed parts. To overcome this limitation, a new route to functionalize the surface of commercially available polymer particles (PA12; PE-HD; PP) using an atmospheric plasma jet in combination with a fluidized bed reactor has been investigated. Consequently, an improvement of adhesion and wettability [2] of the polymer surface without restraining the bulk properties of the powder is achieved. The atmospheric plasma jet process can provide reactive species at moderate temperatures which are suitable for polymer material. The functionalization of the polymer powders improves the quality of the devices build in a SLS-process.

  8. Fabrication of a reinforced polymer microstructure using femtosecond laser material processing

    NASA Astrophysics Data System (ADS)

    Alubaidy, M.; Venkatakrishnan, K.; Tan, B.

    2010-05-01

    This paper presents a new method for the formation of microfeatures with reinforced polymer using femtosecond laser material processing. The femtosecond laser was used for the generation of a three-dimensional interweaved nanofiber and the construction of microfeatures, such as microchannels and voxels, through two-photon polymerization of a nanofiber-dispersed polymer resin. This new method has the potential of direct fabrication of reinforced micro/nanostructures.

  9. Enhanced oil recovery process using a hydrophobic associative composition containing a hydrophilic/hydrophobic polymer

    SciTech Connect

    Evani, S.

    1989-03-21

    An enhanced oil recovery process is described, which comprises forcing an aqueous flooding medium from an injection well through a subterranean formation toward a producing well wherein the flooding medium contains a mobility control agent which is soluble in an aqueous flooding medium. The agent consists of a hydrophilic/hydrophobic polymer having hydrophobic moieties and a water-dispersible, nonionic surfactant having hydrophobic groups that are capable of associating with the hydrophobic moieties of the polymer wherein the proportion of the polymer and the surfactant is such that, at ambient conditions, water containing 0.5 weight percent of the agent has a viscosity at least twice the viscosity of water. The agent is prepared by carrying out the polymerization to form the polymer in the presence of the nonionic surfactant, the ratio of the surfactant to the polymer in the agent being sufficient to provide a viscosity at least twice that of an aqueous solution containing only the polymer, the hydrophobic polymer being a copolymer of a hydrophilic/water-soluble monomer and a water-insoluble monomer selected from the group consisting of higher alkyl ester of ..cap alpha..,..beta..-ethylenically unsaturated carboxylic acids wherein alkyl has from 8 to 20 carbons, alkylaryl esters of ethylenically unsaturated carboxylic acids, N-alkylethylenically unsaturated amides wherein alkyl has from 8 to 20 carbon atoms; vinyl alkylates wherein alkyl has at least 8 carbons and ar-alkyl styrenes wherein alkyl has at least 4 carbons.

  10. Filling and Transcription Behavior of Molten Polymer Coating on Microstructures in Melt-Transcription-Molding Process

    NASA Astrophysics Data System (ADS)

    Ito, Hiroshi; Satoh, Isao; Saito, Takushi; Yakemoto, Kazutoshi

    To clarify the fabrication mechanism of molten polymer coating on microstructures such as optical display parts and bio-tip in Melt-Transcription-Molding (MTM) process, the transcription experiments between a metal stamper engraved with microstructures and a molten polymer (PC: polycarbonate and COC: cyclo-olefin copolymer) were carried out under various molding conditions (mold temperature, polymer temperature, polymer pressure and coating speed) and transcript results were evaluated from the dimensional aspect. In this study the complete transcription of the microstructures was obtained at mold temperature of 170°C for COC and 175°C for PC, respectively. However, the rim height of the microstructure was increased and its center depth was decreased, when lower mold temperatures were applied. From these experimental results, it was suggested that the adhesion force between a molten polymer filled with the microstructure and the metal mold surface plays an important role in fixing the transcript shape of the microstructure against the elastic recovery force and/or shrinkage by cooling. Furthermore, a model to explain the filling and transcription behavior of molten polymers was proposed from viscoelastic properties of each polymer, and it was confirmed that predicted microstructure geometries deduced with the model are well fitted with the transcript results which were experimentally obtained under various mold temperatures.

  11. Improving conducting polymer electrochromic speeds and depositing aligned polymeric nanofibers by electrospinning process

    NASA Astrophysics Data System (ADS)

    Asemota, Chris I.

    The effects of film thickness and porosity on electrochromic switching time of conducting polymers was pursued to determine the morphology influence on ions transport during oxidation step of the redox process, affording sub-second or seconds switching times. Electrospinning technique provided non-woven nanofiber mats, while spin coating and electropolymerization of monomer (N3T) provided films. Porosity decreased as depositing method changed from electrospinning to spin coating. In electrochemical oxidation, the electrons leave the polymer at the metal electrode-polymer film interface, and counter ions arrive at the polaron-bipolaron sites left in the polymer, through polymer-electrolyte interface. Counter ion diffusion in conducting polymers are film thickness limited at increasing thickness and inability of ions to reach holes sites on the oxidizing polymer accounts for long switching speeds, introducing extensive and micro pores and high surface areas should lead to decreasing electrochromic switching speed to single digit time in seconds (for display and vision applications), while increasing the maximum optical switching contrast due to increased fiber mat thicknesses. Photolithographic patterning of nanofiber mats of the conducting polymer precursor having photo cross-linking unit was also explored. The photo-crosslinkable polymer was prepared by including norborene methacrylate (NMA) units to the polymer backbone during precursor polymerization, yielding a terpolymer poly(N3T-NA-NMA). The influence of photo crosslinking on electrochemical switching in conducting polymer nanofibers, and effect of developing parameters (solvent and time) on pattern transfer to the nanofiber mat was investigated and showed no influence on the electrochemical redox of the polymer. Solvents suitable for dissolving the polymer were investigated as developers with results showing non-differentiable pattern transfer for all suitable solvents, and no net preference to solvent choice

  12. Development and Testing of Abrasion Resistant Hard Coats For Polymer Film Reflectors: Preprint

    SciTech Connect

    Jorgensen, G.; Gee, R.; DiGrazia, M.

    2010-10-01

    Reflective polymer film technology can significantly reduce the cost of solar reflectors and installed Concentrated Solar Power (CSP) plants by both reduced material cost and lower weight. One challenge of polymer reflectors in the CSP environment pertains to contact cleaning methods typically used with glass mirrors. Such contact cleaning methods can scratch the surface of polymer reflectors and thereby reduce specular reflectance. ReflecTech, Inc. (a subsidiary of SkyFuel, Inc.) and the National Renewable Energy Laboratory (NREL) initiated a cooperative research and development agreement (CRADA) to devise and develop an abrasion resistant coating (ARC) suitable for deposition onto polymer based mirror film. A number of candidate ARC products were identified as candidate formulations. Industrial collaborators prepared samples having their ARCs deposited onto ReflecTech Mirror Film pre-laminated to aluminum sheet substrates. Samples were provided for evaluation and subjected to baseline (unweathered) and accelerated exposure conditions and subsequently characterized for abrasion resistance and adhesion. An advanced ARC product has been identified that exhibits outstanding initial abrasion resistance and adhesion to ReflecTech Mirror Film. These properties were also retained after exposure to the various accelerated stress conditions. This material has been successfully manufactured as a 1.5 m wide roll-to-roll construction in a production environment.

  13. Novel low-dielectric constant photodefinable polyimides for low-temperature polymer processing

    NASA Astrophysics Data System (ADS)

    Yamanaka, Kazuhiro; Romeo, Michael; Maeda, Kazuhiko; Henderson, Clifford L.

    2006-03-01

    Current photosensitive polyimide formulations that can be developed in aqueous alkaline developers are based on the use of either (1) soluble poly(amic acid) precursor polymers or (2) polyimides functionalized with hydrophilic groups (e.g. phenol). The use of poly(amic acid) polymers requires the subsequent high temperature thermal cyclization of the polymer after imaging to produce the desired polyimide which can prevent ue of such materials in many applications. However, the use of pre-imidized poliyimides by imparting solubility with hydrophilic groups also is problematic since the presence of such groups in the polymer generally degrades the dielectric constant and water uptake performance of such materials. The goal of the work in this paper was to overcome these problems by developing new low dielectric constant polyimides that can be formulated into photo-definable materials and processed at low temperatures. In this work the use of a novel hexafluoroisopropanol (HFA)-substituted diamine to synthesize novel poly(amic-acid) and polyimide polymers is reported. The addition of HFA to the polymers is shown to produce polyimides which are soluble in both common casting solvents and 0.26 N TMAH alkaline developers. A photosentitive polyimide composition based on formulation of the HFA-subtituted polyimide with 20 wt% of a DNQ inhibitor is shown to produce high resolution patterns with a sensitivity of 170 mJ/cm2 and a contrast of 1.32 using I-line exposure. The HFA groups in the polymers are contained on a substituent group attached to the main chain by an ester linkage. It is shown that these HFA-substituent side-groups can be easily removed from the polymer after development of the patterned image by thermal treatment of the polymer at temperatures above 280 °C. The cleavage of the HFA side groups produces a polymer which does not swell and is insoluble in aqueous alkaline developers. Polyimide film properties including dissolution rate, dielectric constant

  14. Unravelling the working junction of aqueous-processed polymer-nanocrystal solar cells towards improved performance.

    PubMed

    Chen, Zhaolai; Du, Xiaohang; Jin, Gan; Zeng, Qingsen; Liu, Fangyuan; Yang, Bai

    2016-06-21

    Hybrid solar cells (HSCs) based on aqueous polymers and nanocrystals are attractive due to their environmental friendliness and cost effectiveness. In this study, HSCs are fabricated from a series of water-soluble polymers with different highest occupied molecular orbital (HOMO) levels and nanocrystals with different Fermi levels. We demonstrate that the working principle of the aqueous-processed HSCs follows a p-n junction instead of a type-II heterojunction. The function of the polymer is to provide an interface dipole which can improve the build-in potential of the HSCs. Subsequently, the aqueous-processed HSCs are optimized following a p-n junction and an improved PCE of 5.41% is achieved, which is the highest for aqueous-processed HSCs. This study will provide instructive guidelines for the development of aqueous-processed HSCs. PMID:27229447

  15. A novel process route for the production of spherical SLS polymer powders

    SciTech Connect

    Schmidt, Jochen; Sachs, Marius; Blümel, Christina; Winzer, Bettina; Toni, Franziska; Wirth, Karl-Ernst; Peukert, Wolfgang

    2015-05-22

    Currently, rapid prototyping gradually is transferred to additive manufacturing opening new applications. Especially selective laser sintering (SLS) is promising. One drawback is the limited choice of polymer materials available as optimized powders. Powders produced by cryogenic grinding show poor powder flowability resulting in poor device quality. Within this account we present a novel process route for the production of spherical polymer micron-sized particles of good flowability. The feasibility of the process chain is demonstrated for polystyrene e. In a first step polymer microparticles are produced by a wet grinding method. By this approach the mean particle size and the particle size distribution can be tuned between a few microns and several 10 microns. The applicability of this method will be discussed for different polymers and the dependencies of product particle size distribution on stressing conditions and process temperature will be outlined. The comminution products consist of microparticles of irregular shape and poor powder flowability. An improvement of flowability of the ground particles is achieved by changing their shape: they are rounded using a heated downer reactor. The influence of temperature profile and residence time on the product properties will be addressed applying a viscous-flow sintering model. To further improve the flowability of the cohesive spherical polymer particles nanoparticles are adhered onto the microparticles’ surface. The improvement of flowability is remarkable: rounded and dry-coated powders exhibit a strongly reduced tensile strength as compared to the comminution product. The improved polymer powders obtained by the process route proposed open new possibilities in SLS processing including the usage of much smaller polymer beads.

  16. A novel process route for the production of spherical SLS polymer powders

    NASA Astrophysics Data System (ADS)

    Schmidt, Jochen; Sachs, Marius; Blümel, Christina; Winzer, Bettina; Toni, Franziska; Wirth, Karl-Ernst; Peukert, Wolfgang

    2015-05-01

    Currently, rapid prototyping gradually is transferred to additive manufacturing opening new applications. Especially selective laser sintering (SLS) is promising. One drawback is the limited choice of polymer materials available as optimized powders. Powders produced by cryogenic grinding show poor powder flowability resulting in poor device quality. Within this account we present a novel process route for the production of spherical polymer micron-sized particles of good flowability. The feasibility of the process chain is demonstrated for polystyrene e. In a first step polymer microparticles are produced by a wet grinding method. By this approach the mean particle size and the particle size distribution can be tuned between a few microns and several 10 microns. The applicability of this method will be discussed for different polymers and the dependencies of product particle size distribution on stressing conditions and process temperature will be outlined. The comminution products consist of microparticles of irregular shape and poor powder flowability. An improvement of flowability of the ground particles is achieved by changing their shape: they are rounded using a heated downer reactor. The influence of temperature profile and residence time on the product properties will be addressed applying a viscous-flow sintering model. To further improve the flowability of the cohesive spherical polymer particles nanoparticles are adhered onto the microparticles' surface. The improvement of flowability is remarkable: rounded and dry-coated powders exhibit a strongly reduced tensile strength as compared to the comminution product. The improved polymer powders obtained by the process route proposed open new possibilities in SLS processing including the usage of much smaller polymer beads.

  17. Tailoring the physical properties of homopolymers and polymer nanocomposites via solid-state processing

    NASA Astrophysics Data System (ADS)

    Pierre, Cynthia

    Numerous approaches can be used to modify polymer properties. In this thesis, it is demonstrated that an innovative, continuous, industrially scalable process called solid-state shear pulverization (SSSP) can be used to enhance polymer properties with and without the addition of nanofillers. The SSSP process employs a modified twin-screw extruder in which the barrel is cooled rather than heated, resulting in the polymer being processed at a temperature below its glass transition temperature, if the polymer is amorphous, or its melt transition temperature, if the polymer is semi-crystalline. The material processed via SSSP experiences high levels of shear and compressive stresses, resulting in many repeated fragmentation and fusion steps during pulverization, which can lead to mechanochemistry. This research provides the first in-depth study on the effect of SSSP processing on the molecular structure as well as physical properties of homopolymers. Rheological characterization has demonstrated an increase in the melt viscosity of pulverized poly(ethylene terephthalate) (PET), which can be ascribed to the in situ formation of lightly branched PET. Further evidence of branched PET is provided via a dramatic increase in the rate of crystallization of the pulverized samples. These results suggest that SSSP processing can enhance the reuse and recyclability of PET. While SSSP processing has dramatic effects on the structure of polyesters and consequently their properties, a mild effect is observed for polyolefins. This thesis also demonstrates via a combination of methods that the well-exfoliated state can be achieved via SSSP processing of various polymer nanocomposites, using as-received, unmodified fillers. For example, extensive comparisons are made concerning the thermal stability in air or nitrogen atmosphere of polypropylene (PP)/clay, PP/graphite, and PP/carbon nanotube (CNT) nanocomposites made by SSSP. These comparisons suggest that the mechanism by which CNTs

  18. Photothermal Property of Metal Nanoparticles and its Application in Polymer Processing

    NASA Astrophysics Data System (ADS)

    Maity, Somsubhra

    The surface plasmon resonance of metal nanoparticles is responsible for their unique optical properties. One of those properties is the capability to transform incident light, at the resonance frequency, into heat energy. The heat is dissipated into the surrounding medium thereby causing a rise in the local temperature. In this work, I describe the methods used to generate plasmonic heat in a polymer matrix and the conditions required for thermal processing of polymers via this approach. The goal of this study is to present photothermal heating as an alternative technique to process polymers, and demonstrate the efficacy of the technique to initiate local phase transformation or actuation or enhance mechanical properties. We successfully demonstrate that low intensity resonant light can be used to generate heat within the polymer matrix and even melt polymers with low melting temperatures. In Chapters 2 and 3, I describe the different factors governing the efficient transformation of incident light energy to heat, and the conditions required to processing different polymer types and polymer morphologies. In Chapter 3, I also describe a fluorescence-based temperature-sensing technique which aids in remotely quantifying the heat produced under different conditions. This helps in monitoring the average temperature of the bulk sample in real time. The heating can be greatly manipulated by modifying not just internal factors like concentration and light intensity, but also external conditions such as the surrounding environment. The heating properties of different shapes of nanoparticles are also studied. In Chapter 4-6, I describe the use of cylindrical nanorods to generate heat to alter the polymer matrix. The anisotropic properties of nanorods are exploited to accomplish polarizationdependent annealing of polymer matrices. The fabrication, characterization and selective processing of aligned nanofibrous polymer samples is described in Chapter 4. Fluorescence

  19. Hydrothermal Synthesis and Processing of Barium Titanate Nanoparticles Embedded in Polymer Films.

    PubMed

    Toomey, Michael D; Gao, Kai; Mendis, Gamini P; Slamovich, Elliott B; Howarter, John A

    2015-12-30

    Barium titanate nanoparticles embedded in flexible polymer films were synthesized using hydrothermal processing methods. The resulting films were characterized with respect to material composition, size distribution of nanoparticles, and spatial location of particles within the polymer film. Synthesis conditions were varied based on the mechanical properties of the polymer films, ratio of polymer to barium titanate precursors, and length of aging time between initial formulations of the solution to final processing of nanoparticles. Block copolymers of poly(styrene-co-maleic anhydride) (SMAh) were used to spatially separate titanium precursors based on specific chemical interactions with the maleic anhydride moiety. However, the glassy nature of this copolymer restricted mobility of the titanium precursors during hydrothermal processing. The addition of rubbery butadiene moieties, through mixing of the SMAh with poly(styrene-butadiene-styrene) (SBS) copolymer, increased the nanoparticle dispersion as a result of greater diffusivity of the titanium precursor via higher mobility of the polymer matrix. Additionally, an aminosilane was used as a means to retard cross-linking in polymer-metalorganic solutions, as the titanium precursor molecules were shown to react and form networks prior to hydrothermal processing. By adding small amounts of competing aminosilane, excessive cross-linking was prevented without significantly impacting the quality and composition of the final barium titanate nanoparticles. X-ray diffraction and X-ray photoelectron spectroscopy were used to verify nanoparticle compositions. Particle sizes within the polymer films were measured to be 108 ± 5 nm, 100 ± 6 nm, and 60 ± 5 nm under different synthetic conditions using electron microscopy. Flexibility of the films was assessed through measurement of the glass transition temperature using dynamic mechanical analysis. Dielectric permittivity was measured using an impedance analyzer.

  20. Electric poling-assisted additive manufacturing process for PVDF polymer-based piezoelectric device applications

    NASA Astrophysics Data System (ADS)

    Lee, ChaBum; Tarbutton, Joshua A.

    2014-09-01

    This paper presents a new additive manufacturing (AM) process to directly and continuously print piezoelectric devices from polyvinylidene fluoride (PVDF) polymeric filament rods under a strong electric field. This process, called ‘electric poling-assisted additive manufacturing or EPAM, combines AM and electric poling processes and is able to fabricate free-form shape piezoelectric devices continuously. In this process, the PVDF polymer dipoles remain well-aligned and uniform over a large area in a single design, production and fabrication step. During EPAM process, molten PVDF polymer is simultaneously mechanically stresses in-situ by the leading nozzle and electrically poled by applying high electric field under high temperature. The EPAM system was constructed to directly print piezoelectric structures from PVDF polymeric filament while applying high electric field between nozzle tip and printing bed in AM machine. Piezoelectric devices were successfully fabricated using the EPAM process. The crystalline phase transitions that occurred from the process were identified by using the Fourier transform infrared spectroscope. The results indicate that devices printed under a strong electric field become piezoelectric during the EPAM process and that stronger electric fields result in greater piezoelectricity as marked by the electrical response and the formation of sharper peaks at the polar β crystalline wavenumber of the PVDF polymer. Performing this process in the absence of an electric field does not result in dipole alignment of PVDF polymer. The EPAM process is expected to lead to the widespread use of AM to fabricate a variety of piezoelectric PVDF polymer-based devices for sensing, actuation and energy harvesting applications with simple, low cost, single processing and fabrication step.

  1. Hot water, surfactant, and polymer flooding process for heavy oil

    SciTech Connect

    Ashrawi, S.S.

    1992-01-28

    This patent describes a method of recovering viscous petroleum from a subterranean, porous and permeable formation penetrated by at least one injection well and by at least one production well, both in fluid communication with the formation. It comprises injecting a thermal recovery fluid into the formation to heat the formation above its natural temperature; injecting a surfactant solution into the formation, the surfactant solution comprising a mixture of petrochemical sulfonate and a co-surfactant, the co-surfactant being an olefin sulfonate having the general formula CH{sub 3}{emdash}(CH{sub 2}){sub x}{emdash}CH{double bond}CH{emdash}(CH{sub 2}){sub y}{emdash}SO{sub 3}{sup {minus}}M{sup +}, wherein x is 0 to 15, x + y is 9 to 15, and M is a monovalent cation; injecting a water-soluble polymer solution into the formation through the same well the surfactant solution was injected into; and recovering petroleum through a production well.

  2. Probing polymer crystallization at processing-relevant cooling rates with synchrotron radiation

    SciTech Connect

    Cavallo, Dario; Portale, Giuseppe; Androsch, René

    2015-12-17

    Processing of polymeric materials to produce any kind of goods, from films to complex objects, involves application of flow fields on the polymer melt, accompanied or followed by its rapid cooling. Typically, polymers solidify at cooling rates which span over a wide range, from a few to hundreds of °C/s. A novel method to probe polymer crystallization at processing-relevant cooling rates is proposed. Using a custom-built quenching device, thin polymer films are ballistically cooled from the melt at rates between approximately 10 and 200 °C/s. Thanks to highly brilliant synchrotron radiation and to state-of-the-art X-ray detectors, the crystallization process is followed in real-time, recording about 20 wide angle X-ray diffraction patterns per second while monitoring the instantaneous sample temperature. The method is applied to a series of industrially relevant polymers, such as isotactic polypropylene, its copolymers and virgin and nucleated polyamide-6. Their crystallization behaviour during rapid cooling is discussed, with particular attention to the occurrence of polymorphism, which deeply impact material’s properties.

  3. Mechanistic study of the Polymer-Induced Liquid-Precursor (PILP) process: Relevance to biomineralization

    NASA Astrophysics Data System (ADS)

    Dai, Lijun

    Biomineralization is a process in which cells construct a mineralization platform based on framework proteins and water-soluble proteins, and utilize some transportation vesicles, such as matrix vesicles to regulate the transportation of ions and precursor phases. The mineral morphologies formed by the Polymer-Induced Liquid-Precursor (PILP) process, which utilizes acidic polypeptides or polymers to mimic the acidic proteins in biominerals, have been shown to have a great similarity with many biominerals. This drives us to investigate the important factors and underlying mechanisms governing the generation, stabilization and transformation of polymer-induced liquid-precursor phases. First, the PILP phase composition has been characterized during a reaction time series using a combination of measuring water loss with elemental analysis. This phase is found to be a highly hydrated phase with a large amount of acidic polymers entrapped within. By FT-Raman, it is found that these acidic polymers can chelate with calcium ions by breaking the initial calcium-water complexes, liberating free water near the calcium-polymer complexes. It is then shown that when calcium carbonate complexes are formed, most of the acidic polymer can be liberated from the formed precursor phase to re-induce more PILP phase. By FTIR, it is found that acidic polymers can stabilize the PILP amorphous phase. The extended stabilization lifetime of the PILP phase is due to the entrapped acidic polymers and the free water in the precursor phase. They disrupt the ordered packing of the calcium carbonate complexes. Second, to investigate how different protein structures would affect the PILP phase quality, quantity, and stability, a series of synthetic peptides mimicking proteins involved in biomineralization were synthesized and applied to generate the PILP process using various techniques. Peptides with high charge density, phosphorylation density and molecular weight to a limit of 5000 Da in

  4. Structure-induced resonant tail-state regime absorption in polymer: fullerene bulk-heterojunction solar cells

    NASA Astrophysics Data System (ADS)

    Pfadler, Thomas; Kiel, Thomas; Stärk, Martin; Werra, Julia F. M.; Matyssek, Christian; Sommer, Daniel; Boneberg, Johannes; Busch, Kurt; Weickert, Jonas; Schmidt-Mende, Lukas

    2016-05-01

    In this work, we present resonant tail-state regime absorption enhanced organic photovoltaics. We combine periodically structured TiO2 bottom electrodes with P3HT-PCBM bulk-heterojunction solar cells in an inverted device configuration. The wavelength-scale patterns are transferred to the electron-selective bottom electrodes via direct laser interference patterning, a fast method compatible with roll-to-roll processing. Spectroscopic and optoelectronic device measurements suggest polarization-dependent absorption enhancement along with photocurrent generation unambiguously originating from the population of tail states. We discuss the effects underlying these absorption patterns with the help of electromagnetic simulations using the discontinuous Galerkin time domain method. For this, we focus on the total absorption spectra along with spatially resolved power loss densities. Our simulations stress the tunability of the absorption resonances towards arbitrary wavelength regions.

  5. Development of a novel and efficient cell culture flocculation process using a stimulus responsive polymer to streamline antibody purification processes.

    PubMed

    Kang, Yun Kenneth; Hamzik, James; Felo, Michael; Qi, Bo; Lee, Julia; Ng, Stanley; Liebisch, Gregory; Shanehsaz, Behnam; Singh, Nripen; Persaud, Kris; Ludwig, Dale L; Balderes, Paul

    2013-11-01

    Recent advances in mammalian cell culture processes have significantly increased product titers, but have also resulted in substantial increases in cell density and cellular debris as well as process and product related impurities. As such, with improvements in titer, corresponding improvements in downstream processing are essential. In this study we have developed an alternative antibody harvest process that incorporates flocculation using a novel stimulus responsive polymer, benzylated poly(allylamine), followed by depth filtration. As tested on multiple antibodies, this process demonstrates high process yield, improved clearance of cells and cell debris, and efficient reduction of aggregates, host cell proteins (HCP) and DNA. A wide operating window was established for this novel flocculation process through design of experiments condition screening and optimization. Residual levels of impurities in the Protein A eluate were achieved that potentially meet requirements of drug substance and thus alleviate the burden for further impurities removal in subsequent chromatography steps. In addition, efficient clearance of residual polymer was demonstrated using a fluorescence tagged polymer in the presence of a stimulus reagent. The mechanism of HCP and aggregates removal during flocculation was also explored. This novel and efficient process can be easily integrated into current mAb purification platforms, and may overcome downstream processing challenges.

  6. Influence Of The Microinjection Moulding Process On The Crystalline Orientation And Morphology Of Semicrystalline Polymers

    NASA Astrophysics Data System (ADS)

    Malhab, Nada Bou; Régnier, Gilles

    2011-05-01

    Microinjection moulding (μIM) seems to be a key for the large scale production of polymer microparts. For semicrystalline polymers, the crystallisation under high shear and cooling rates induces specific morphologies and properties and thus takes tremendous importance in microinjection process compared to classical injection moulding (IM) process where wall thicknesses are generally larger than 1mm. Two semicrystalline polymers were microinjected, a high density polyethylene and a polyamide 12 in plaque cavities having thicknesses of 0.3 and 0.5mm. Analyses obtained by optical microscopy show that the crystalline morphologies vary between micro- and macro- parts. While a `skin-core' morphology is present for the macropart, the μpart exhibits a specific morphology. The X-ray scattering at small angles (SAXS) studies show an orientation of HDPE lamellae whatever the conditions of microinjection whereas the orientation of PA12 lamellae is either isotropic or anisotropic depending on the thickness of molded parts.

  7. The influence of binary processing additives on the performance of polymer solar cells

    NASA Astrophysics Data System (ADS)

    Liu, Chang; Hu, Xiaowen; Zhong, Chengmei; Huang, Mingjun; Wang, Kai; Zhang, Zhan; Gong, Xiong; Cao, Yong; Heeger, Alan J.

    2014-11-01

    In this study, we report the investigation of the influence of binary processing additives, 1,8-octanedithiol (ODT) and 1-chloronaphthalene (CN) on the performance of polymer solar cells (PSCs). It was found that the power conversion efficiency (PCE) can be enhanced to 8.55% from the PSCs processed with binary processing additives as compared with ~6.50% from the PSCs processed with either ODT or CN processing additives. With binary processing additives, the crystallinity of the electron donor polymer, poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2 ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl

  8. Supercritical carbon dioxide-processed resorbable polymer nanocomposites for bone graft substitute applications

    NASA Astrophysics Data System (ADS)

    Baker, Kevin C.

    Numerous clinical situations necessitate the use of bone graft materials to enhance bone formation. While autologous and allogenic materials are considered the gold standards in the setting of fracture healing and spine fusion, their disadvantages, which include donor site morbidity and finite supply have stimulated research and development of novel bone graft substitute materials. Among the most promising candidate materials are resorbable polymers, composed of lactic and/or glycolic acid. While the characteristics of these materials, such as predictable degradation kinetics and biocompatibility, make them an excellent choice for bone graft substitute applications, they lack mechanical strength when synthesized with the requisite porous morphology. As such, porous resorbable polymers are often reinforced with filler materials. In the presented work, we describe the use of supercritical carbon dioxide (scCO2) processing to create porous resorbable polymeric constructs reinforced by nanostructured, organically modified Montmorillonite clay (nanoclay). scCO2 processing simultaneously disperses the nanoclay throughout the polymeric matrix, while imparting a porous morphology to the construct conducive to facilitating cellular infiltration and neoangiogenesis, which are necessary components of bone growth. With the addition of as little as 2.5wt% of nanoclay, the compressive strength of the constructs nearly doubles putting them on par with human cortico-cancellous bone. Rheological measurements indicate that the dominant mode of reinforcement of the nanocomposite constructs is the restriction of polymer chain mobility. This restriction is a function of the positive interaction between polymer chains and the nanoclay. In vivo inflammation studies indicate biocompatibility of the constructs. Ectopic osteogenesis assays have determined that the scCO2-processed nanocomposites are capable of supporting growth-factor induced bone formation. scCO 2-processed resorbable

  9. Process for making polymers comprising derivatized carbon nanotubes and compositions thereof

    NASA Technical Reports Server (NTRS)

    Tour, James M. (Inventor); Bahr, Jeffrey L. (Inventor); Yang, Jiping (Inventor)

    2007-01-01

    The present invention incorporates new processes for blending derivatized carbon nanotubes into polymer matrices to create new polymer/composite materials. When modified with suitable chemical groups using diazonium chemistry, the nanotubes can be made chemically compatible with a polymer matrix, allowing transfer of the properties of the nanotubes (such as mechanical strength) to the properties of the composite material as a whole. To achieve this, the derivatized (modified) carbon nanotubes are physically blended with the polymeric material, and/or, if desired, allowed to react at ambient or elevated temperature. These methods can be utilized to append functionalities to the nanotubes that will further covalently bond to the host polymer matrix, or directly between two tubes themselves. Furthermore, the nanotubes can be used as a generator of polymer growth, wherein the nanotubes are derivatized with a functional group that is an active part of a polymerization process, which would also result in a composite material in which the carbon nanotubes are chemically involved.

  10. Novel Controlled Release Polymer-Lipid Formulations Processed by Hot Melt Extrusion.

    PubMed

    Maniruzzaman, Mohammed; Islam, Muhammad T; Halsey, Sheelagh; Amin, Devyani; Douroumis, Dennis

    2016-02-01

    The aim of the study was to investigate the effect of novel polymer/lipid formulations on the dissolution rates of the water insoluble indomethacin (INM), co-processed by hot melt extrusion (HME). Formulations consisted of the hydrophilic hydroxypropyl methyl cellulose polymer (HPMCAS) and stearoyl macrogol-32 glycerides-Gelucire 50/13 (GLC) were processed with a twin screw extruder to produce solid dispersions. The extrudates characterized by X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC) and hot stage microscopy (HSM) indicated the presence of amorphous INM within the polymer/lipid matrices. In-line monitoring via near-infrared (NIR) spectroscopy revealed significant peak shifts indicating possible interactions and H-bonding formation between the drug and the polymer/lipid carriers. Furthermore, in vitro dissolution studies showed a synergistic effect of the polymer/lipid carrier with 2-h lag time in acidic media followed by enhanced INM dissolution rates at pH > 5.5.

  11. Laser processing of polymer constructs from poly(3-hydroxybutyrate).

    PubMed

    Volova, T G; Tarasevich, A A; Golubev, A I; Boyandin, A N; Shumilova, A A; Nikolaeva, E D; Shishatskaya, E I

    2015-01-01

    CO2 laser radiation was used to process poly(3-hydroxybutyrate) constructs - films and 3D pressed plates. Laser processing increased the biocompatibility of unperforated films treated with moderate uniform radiation, as estimated by the number and degree of adhesion of NIH 3T3 mouse fibroblast cells. The biocompatibility of perforated films modified in the pulsed mode did not change significantly. At the same time, pulsed laser processing of the 3D plates produced perforated scaffolds with improved mechanical properties and high biocompatibility with bone marrow-derived multipotent, mesenchymal stem cells, which show great promise for bone regeneration. PMID:26278920

  12. Laser processing of polymer constructs from poly(3-hydroxybutyrate).

    PubMed

    Volova, T G; Tarasevich, A A; Golubev, A I; Boyandin, A N; Shumilova, A A; Nikolaeva, E D; Shishatskaya, E I

    2015-01-01

    CO2 laser radiation was used to process poly(3-hydroxybutyrate) constructs - films and 3D pressed plates. Laser processing increased the biocompatibility of unperforated films treated with moderate uniform radiation, as estimated by the number and degree of adhesion of NIH 3T3 mouse fibroblast cells. The biocompatibility of perforated films modified in the pulsed mode did not change significantly. At the same time, pulsed laser processing of the 3D plates produced perforated scaffolds with improved mechanical properties and high biocompatibility with bone marrow-derived multipotent, mesenchymal stem cells, which show great promise for bone regeneration.

  13. High magnetic field processing of liquid crystalline polymers

    DOEpatents

    Smith, M.E.; Benicewicz, B.C.; Douglas, E.P.

    1998-11-24

    A process of forming bulk articles of oriented liquid crystalline thermoset material, the material characterized as having an enhanced tensile modulus parallel to orientation of an applied magnetic field of at least 25 percent greater than said material processed in the absence of a magnetic field, by curing a liquid crystalline thermoset precursor within a high strength magnetic field of greater than about 2 Tesla, is provided, together with a resultant bulk article of a liquid crystalline thermoset material, said material processed in a high strength magnetic field whereby said material is characterized as having a tensile modulus parallel to orientation of said field of at least 25 percent greater than said material processed in the absence of a magnetic field.

  14. High magnetic field processing of liquid crystalline polymers

    DOEpatents

    Smith, Mark E.; Benicewicz, Brian C.; Douglas, Elliot P.

    1998-01-01

    A process of forming bulk articles of oriented liquid crystalline thermoset material, the material characterized as having an enhanced tensile modulus parallel to orientation of an applied magnetic field of at least 25 percent greater than said material processed in the absence of a magnetic field, by curing a liquid crystalline thermoset precursor within a high strength magnetic field of greater than about 2 Tesla, is provided, together with a resultant bulk article of a liquid crystalline thermoset material, said material processed in a high strength magnetic field whereby said material is characterized as having a tensile modulus parallel to orientation of said field of at least 25 percent greater than said material processed in the absence of a magnetic field.

  15. Processing of continuous fiber reinforced ceramic composites for ultra high temperature applications using organosilicon polymer precursors

    NASA Astrophysics Data System (ADS)

    Nicholas, James Robert

    The current work is on the development of continuous fiber reinforced ceramic materials (CFCCs) for use in ultra high temperature applications. These applications subject materials to extremely high temperatures(> 2000°C). Monolithic ceramics are currently being used for these applications, but the tendency to fail catastrophically has driven the need for the next generation of material. Reinforcing with continuous fibers significantly improves the toughness of the monolithic materials; however, this is a manufacturing challenge. The development of commercial, low-viscosity preceramic polymers provides new opportunities to fabricate CFCCs. Preceramic polymers behave as polymers at low temperatures and are transformed into ceramics upon heating to high temperatures. The polymer precursors enable the adaptation of well-established polymer processing techniques to produce high quality materials at relatively low cost. In the present work, SMP-10 from Starfire Systems, and PURS from KiON Corp. were used to manufacture ZrB2-SiC/SiC CFCCs using low cost vacuum bagging process in conjunction with the polymer infiltration and pyrolysis process. The microstructure was investigated using scanning electron microscopy and it was determined that the initial greenbody cure produced porosity of both closed and open pores. The open pores were found to be more successfully re-infiltrated using neat resin compared to slurry reinfiltrate; however, the closed pores were found to be impenetrable during subsequent reinfiltrations. The mechanical performance of the manufactured samples was evaluated using flexure tests and found the fiber reinforcement prevented catastrophic failure behavior by increasing fracture toughness. Wedge sample were fabricated and evaluated to demonstrate the ability to produce CFCC of complex geometry.

  16. New Polymer Materials for the Laser Sintering Process: Polypropylene and Others

    NASA Astrophysics Data System (ADS)

    Wegner, Andreas

    Laser sintering of polymers gets more and more importance for small series production. However, there is only a little number of materials available for the process. In most cases parts are build up using polyamide 12 or polyamide 11. Reasons for that are high prices, a restricted availability, poor mechanical part properties or an insufficient understanding of the processing of other materials. These problems result from the complex processing conditions in laser sintering with high requirements on the material's characteristics. Within this area, at the chair for manufacturing technology fundamental knowledge was established. Aim of the presented study was to qualify different polymers for the laser sintering process. Polyethylene, polypropylene, polyamide 6, polyoxymethylene as well as polybutylene terephthalate were analyzed. Within the study problems of qualifying new materials are discussed using some examples. Furthermore, the processing conditions as well as mechanical properties of a new polypropylene compound are shown considering also different laser sintering machines.

  17. A study of the process of nonisothermal decomposition of phenolformaldehyde polymers by differential thermal analysis

    SciTech Connect

    Petrova, O.M.; Fedoseev, S.D.; Komarova, T.V.

    1984-01-01

    A calculation has been made of the activation energy of the thermal decomposition of phenol-formaldehyde polymers. It has been established that for nonisothermal conditions the rate of performance of the process does not affect the effective activation energy calculated by means of Piloyan's equation.

  18. High energy and power density capacitors from solution-processed ternary ferroelectric polymer nanocomposites.

    PubMed

    Li, Qi; Han, Kuo; Gadinski, Matthew Robert; Zhang, Guangzu; Wang, Qing

    2014-09-01

    Concurrent improvements in dielectric constant and breakdown strength are attained in a solution-processed ternary ferroelectric polymer nanocomposite incorporated with two-dimensional boron nitride nanosheets and zero-dimensional barium titanate nanoparticles that synergistically interact to enable a remarkable energy-storage capability, including large discharged energy density, high charge-discharge efficiency, and great power density.

  19. E-Beam Processing of Polymer Matrix Composites for Multifunctional Radiation Shielding

    NASA Technical Reports Server (NTRS)

    Hou, Tan-Hung; Wilson, John W.; Jensen, Brian J.; Thibeault, Sheila A.; Chang, Chie K.; Kiefer, Richard L.

    2005-01-01

    Aliphatic polymers were identified as optimum radiation shielding polymeric materials for building multifunctional structural elements for in-space habitats. Conceptual damage tolerant configurations of polyolefins have been proposed, but many manufacturing issues relied on methods and materials which have sub-optimal radiation shielding characteristics (for example, epoxy matrix and adhesives). In the present approach, we shall investigate e-beam processing technologies for inclusion of high-strength aliphatic polymer reinforcement structures into a highly cross-linked polyolefin matrix. This paper reports the baseline thermo-mechanical properties of low density polyethylene and highly crystallized polyethylene.

  20. Hydrothermal processing of BaTiO{sub 3}/polymer films

    SciTech Connect

    Slamovich, E.B.; Aksay, I.A.

    1994-12-31

    Hydrothermally derived films of BaTiO{sub 3} were fabricated by reacting thin layers of titanium organometallic liquid precursors in aqueous solutions containing Ba(OH){sub 2} and having a high pH. Cubic submicron polycrystalline films of BaTiO{sub 3} (thickness {approx} 1 {mu}m) were formed at 70 C. Low concentrations of block copolymers of polybutadiene and polystyrene were incorporated into the liquid precursor to prevent precursor film cracking. Higher polymer concentrations allowed fabrication of polymer/ceramic composite films by virtue of the low temperature used in hydrothermal processing.

  1. Process for synthesizing a new series of fluorocarbon polymers

    NASA Technical Reports Server (NTRS)

    Toy, M. S.

    1970-01-01

    Two-step process for preparing fluorocarbon materials includes - /1/ adding gaseous fluorine to a polyperfluoropolyene to create fluorocarbon radicals, with reactive sites at unsaturated carbon atoms, and /2/ introducing a monomer, after evacuation of fluorine gas, and allowing copolymerization with the free radicals.

  2. [The modified process for preparing natural organic polymer flocculant chitosan].

    PubMed

    Zeng, D; Yu, G; Zhang, P; Feng, Z

    2001-05-01

    The modified process for preparing chitosan from crab or lobster shells was developed. In the decalcification stage, 10% HCl was used as soaking solution with addition of a small quantity of A as a promoter, and the mass ratio of reactants was 10% HCl:A:crab or lobster shells = 3.5:0.5:1, continuously stirring the crab or lobster shells at 30 degrees C for 3 h in place of simply soaking the crab or lobster shells at room temperature for 16-24 h in the previous process. In the deacetylation stage, 40% NaOH solution was used with addition of a small quantity of B as a promoter, and the mass ratio of reactants was 40% NaOH:B:chitin = 4:0.2:1, keeping reaction at 105 degrees C for 2 h in place of at 115 degrees C for 6 h in the previous process. By this new process, the cost of the raw materials used for preparing chitosan was cut down 49%, the preparation time was shortened by one half, and the main properties of this chitosan such as viscosity, deacetylation and molecular weight all approached or exceeded those of the Sigma' commercial chitosan (Chitosan C-3646).

  3. Polymer's anchoring behavior in liquid crystal cells

    NASA Astrophysics Data System (ADS)

    Cui, Yue

    crystal's interaction and proper selection of the materials (Chapter 5). Also, innovative micro structure can be designed and achieved, like the encapsulated PSCT (Chapter 8) which combines the merits of PDLC and PSCT. Such structure involves two separate polymer constructions. One is to encapsulate large droplets of cholesteric liquid crystal, while the other is inside the droplet to stabilize the cholesteric liquid crystal at transparent state. Thus the mixture has large viewing angle due to similarity to PSCT and is applicable to roll-to-roll manufacture.

  4. Diorganosilacetylene-alt-diorganosilvinylene polymers and a process densifying porous silicon-carbide bodies

    DOEpatents

    Barton, Thomas J.; Ijadi-Maghsoodi, Sina; Pang, Yi

    1994-05-17

    The present invention provides linear organosilicon polymers including acetylene and vinylene moieties, and a process for their preparation. These diorganosilacetylene-alt-diorganosilvinylene linear polymers can be represented by the formula: --[--(R.sup.1)(R.sup.2)Si--C.tbd.C--(R.sup.3)(R.sup.4)Si--CH=CH--].sub.n-- , wherein n.gtoreq.2; and each R.sup.1, R.sup.2, R.sup.3, and R.sup.4 is independently selected from the group consisting of hydrogen, halogen, alkyl, alkenyl, aryl, and aralkyl radicals. The polymers are soluble in organic solvents, air stable, and can be pulled into fibers or cast into films. They can be thermally converted into silicon carbide ceramic materials.

  5. Diorganosilacetylene-alt-diorganosilvinylene polymers and a process densifying porous silicon-carbide bodies

    DOEpatents

    Barton, T.J.; Ijadi-Maghsoodi, S.; Pang, Y.

    1994-05-17

    The present invention provides linear organosilicon polymers including acetylene and vinylene moieties, and a process for their preparation. These diorganosilacetylene-alt-diorganosilvinylene linear polymers can be represented by the formula: --[--(R[sup 1])(R[sup 2])Si--C[triple bond]C-(R[sup 3])(R[sup 4])Si--CH[double bond]CH--][sub n]--, wherein n[>=]2; and each R[sup 1], R[sup 2], R[sup 3], and R[sup 4] is independently selected from the group consisting of hydrogen, halogen, alkyl, alkenyl, aryl, and aralkyl radicals. The polymers are soluble in organic solvents, air stable, and can be pulled into fibers or cast into films. They can be thermally converted into silicon carbide ceramic materials.

  6. Efficient tandem polymer solar cells fabricated by all-solution processing.

    PubMed

    Kim, Jin Young; Lee, Kwanghee; Coates, Nelson E; Moses, Daniel; Nguyen, Thuc-Quyen; Dante, Mark; Heeger, Alan J

    2007-07-13

    Tandem solar cells, in which two solar cells with different absorption characteristics are linked to use a wider range of the solar spectrum, were fabricated with each layer processed from solution with the use of bulk heterojunction materials comprising semiconducting polymers and fullerene derivatives. A transparent titanium oxide (TiO(x)) layer separates and connects the front cell and the back cell. The TiO(x) layer serves as an electron transport and collecting layer for the first cell and as a stable foundation that enables the fabrication of the second cell to complete the tandem cell architecture. We use an inverted structure with the low band-gap polymer-fullerene composite as the charge-separating layer in the front cell and the high band-gap polymer composite as that in the back cell. Power-conversion efficiencies of more than 6% were achieved at illuminations of 200 milliwatts per square centimeter. PMID:17626879

  7. Influence of macromolecular architecture on necking in polymer extrusion film casting process

    SciTech Connect

    Pol, Harshawardhan; Banik, Sourya; Azad, Lal Busher; Doshi, Pankaj; Lele, Ashish; Thete, Sumeet

    2015-05-22

    Extrusion film casting (EFC) is an important polymer processing technique that is used to produce several thousand tons of polymer films/coatings on an industrial scale. In this research, we are interested in understanding quantitatively how macromolecular chain architecture (for example long chain branching (LCB) or molecular weight distribution (MWD or PDI)) influences the necking and thickness distribution of extrusion cast films. We have used different polymer resins of linear and branched molecular architecture to produce extrusion cast films under controlled experimental conditions. The necking profiles of the films were imaged and the velocity profiles during EFC were monitored using particle tracking velocimetry (PTV) technique. Additionally, the temperature profiles were captured using an IR thermography and thickness profiles were calculated. The experimental results are compared with predictions of one-dimensional flow model of Silagy et al{sup 1} wherein the polymer resin rheology is modeled using molecular constitutive equations such as the Rolie-Poly (RP) and extended Pom Pom (XPP). We demonstrate that the 1-D flow model containing the molecular constitutive equations provides new insights into the role of macromolecular chain architecture on film necking.{sup 1}D. Silagy, Y. Demay, and J-F. Agassant, Polym. Eng. Sci., 36, 2614 (1996)

  8. An application of CO{sub 2} laser interference heating for polymer injection molding process

    SciTech Connect

    Saito, Takushi; Satoh, Isao; Kurosaki, Yasuo

    1999-07-01

    In this paper, the authors studied the small scale (less than 1 mm) local heat transfer control of injection molded polymer products by using CO{sub 2} laser interferometry. This technique could provide precise local temperature control of the product surface during the process. Residual birefringence of the irradiated surface was successfully distributed according to the interference pattern. This scale of heat transfer control has not been realized through common conductive heat transfer methods. To establish the laser interference heating, a CO{sub 2} laser, a set of optical equipment, and a transparent window of Zinc-selenide were used. To control the heat transfer on the molded polymer surface, the interfered laser beam was introduced through the window. Polystyrene resin was used to investigate the feasibility of this method. In the experiment, the control ability of the property distribution on a molded polymer surface was studied under various conditions. To confirm the viability of this technique, optical strain frozen in the molded polymer surface was measured with a polarizing microscope as birefringence. As the result, it was clearly shown that the residual birefringence had an equal spaced distribution. Also, the contrast between the irradiated and un-irradiated portions was obvious regardless of the polymer melt velocity and radiation intensity. This method may be applied to the production of diffraction gratings which have geometrically smooth surfaces.

  9. Influence of macromolecular architecture on necking in polymer extrusion film casting process

    NASA Astrophysics Data System (ADS)

    Pol, Harshawardhan; Banik, Sourya; Azad, Lal Busher; Thete, Sumeet; Doshi, Pankaj; Lele, Ashish

    2015-05-01

    Extrusion film casting (EFC) is an important polymer processing technique that is used to produce several thousand tons of polymer films/coatings on an industrial scale. In this research, we are interested in understanding quantitatively how macromolecular chain architecture (for example long chain branching (LCB) or molecular weight distribution (MWD or PDI)) influences the necking and thickness distribution of extrusion cast films. We have used different polymer resins of linear and branched molecular architecture to produce extrusion cast films under controlled experimental conditions. The necking profiles of the films were imaged and the velocity profiles during EFC were monitored using particle tracking velocimetry (PTV) technique. Additionally, the temperature profiles were captured using an IR thermography and thickness profiles were calculated. The experimental results are compared with predictions of one-dimensional flow model of Silagy et al1 wherein the polymer resin rheology is modeled using molecular constitutive equations such as the Rolie-Poly (RP) and extended Pom Pom (XPP). We demonstrate that the 1-D flow model containing the molecular constitutive equations provides new insights into the role of macromolecular chain architecture on film necking.1D. Silagy, Y. Demay, and J-F. Agassant, Polym. Eng. Sci., 36, 2614 (1996).

  10. Infrared radiometry using a dielectric-silver-coated hollow glass waveguide for polymer processing

    NASA Astrophysics Data System (ADS)

    Bendada, A.; Cole, K.; Lamontagne, M.; Simard, Y.

    2004-01-01

    We describe a novel on-line infrared method for remote sensing of the surface and the bulk temperatures of a polymer film during injection molding. The method may also be applied to other polymer forming processes such as extrusion and blow molding. The key feature of the new method is the use of a hollow waveguide that is incorporated into the injection mold to transmit the thermal radiation from the target to the sensor. The main characteristic of the hollow waveguide is that it exhibits low transmission loss of the thermal energy in the mid and far infrared, and no end reflection. This allows measurement of quite low temperatures, as low as near room temperature. Conventional optical fiber thermometers can neither measure such low temperature ranges nor measure the polymer surface temperature. In this article, we present the first on-line results of critical tests of the new device. A Husky injection molding press was used for the experiments. Good correlation was found between the radiometric results and those obtained with a thermal sensor inserted near the polymer mold interface, and with infrared imaging after the polymer part was ejected from the injection mold.

  11. NOCHAR Polymers: An Aqueous and Organic Liquid Solidification Process for Cadarache LOR (Liquides Organiques Radioactifs) - 13195

    SciTech Connect

    Vaudey, Claire-Emilie; Renou, Sebastien; Porco, Julien; Kelley, Dennis; Cochaud, Chantal

    2013-07-01

    To handle the Very Low Level Waste (VLLW) and the Low Level Waste (LLW) in France, two options can be considered: the incineration at CENTRACO facility and the disposal facility on ANDRA sites. The waste acceptance in these radwaste routes is dependent upon the adequacy between the waste characteristics (physical chemistry and radiological) and the radwaste route specifications. If the waste characteristics are incompatible with the radwaste route specifications (presence of significant quantities of chlorine, fluorine, organic component etc or/and high activity limits), it is necessary to find an alternative solution that consists of a waste pre-treatment process. In the context of the problematic Cadarache LOR (Liquides Organiques Radioactifs) waste streams, two radioactive scintillation cocktails have to be treated. The first one is composed of organic liquids at 13.1 % (diphenyloxazol, mesitylene, TBP, xylene) and water at 86.9 %. The second one is composed of TBP at 8.6 % and water at 91.4 %. They contain chlorine, fluorine and sulphate and have got alpha/beta/gamma spectra with mass activities equal to some kBq.g{sup -1}. Therefore, tritium is present and creates the second problematic waste stream. As a consequence, in order for disposal acceptance at the ANDRA site, it is necessary to pre-treat the waste. The NOCHAR polymers as an aqueous and organic liquid solidification process seem to be an adequate solution. Indeed, these polymers constitute an important variety of products applied to the treatment of radioactive aqueous and organic liquids (solvent, oil, solvent/oil mixing etc) and sludge through a mechanical and chemical solidification process. For Cadarache LOR, N910 and N960 respectively dedicated to the organic and aqueous liquids solidification are considered. With the N910, the organic waste solidification occurs in two steps. As the organic liquid travels moves through the polymer strands, the strands swell and immobilise the liquid. Then as the

  12. THE USE OF POLYMERS IN RADIOACTIVE WASTE PROCESSING SYSTEMS

    SciTech Connect

    Skidmore, E.; Fondeur, F.

    2013-04-15

    The Savannah River Site (SRS), one of the largest U.S. Department of Energy (DOE) sites, has operated since the early 1950s. The early mission of the site was to produce critical nuclear materials for national defense. Many facilities have been constructed at the SRS over the years to process, stabilize and/or store radioactive waste and related materials. The primary materials of construction used in such facilities are inorganic (metals, concrete), but polymeric materials are inevitably used in various applications. The effects of aging, radiation, chemicals, heat and other environmental variables must therefore be understood to maximize service life of polymeric components. In particular, the potential for dose rate effects and synergistic effects on polymeric materials in multivariable environments can complicate compatibility reviews and life predictions. The selection and performance of polymeric materials in radioactive waste processing systems at the SRS are discussed.

  13. Evaluation of extractables in processed and unprocessed polymer materials used for pharmaceutical applications.

    PubMed

    Stults, Cheryl L M; Ansell, Jennifer M; Shaw, Arthur J; Nagao, Lee M

    2015-02-01

    Polymeric materials are often used in pharmaceutical packaging, delivery systems, and manufacturing components. There is continued concern that chemical entities from polymeric components may leach into various dosage forms, particularly those that are comprised of liquids such as parenterals, injectables, ophthalmics, and inhalation products. In some cases, polymeric components are subjected to routine extractables testing as a control measure. To reduce the risk of discovering leachables during stability studies late in the development process, or components that may fail extractables release criteria, it is proposed that extractables testing on polymer resins may be useful as a screening tool. Two studies have been performed to evaluate whether the extractables profile generated from a polymer resin is representative of the extractables profile of components made from that same resin. The ELSIE Consortium pilot program examined polyvinyl chloride and polyethylene, and another study evaluated polypropylene and a copolymer of polycarbonate and acrylonitrile butadiene styrene. The test materials were comprised of polymer resin and processed resin or molded components. Volatile, semi-volatile, and nonvolatile chemical profiles were evaluated after headspace sampling and extraction with solvents of varying polarity and pH. The findings from these studies indicate that there may or may not be differences between extractables profiles obtained from resins and processed forms of the resin depending on the type of material, the compounds of interest, and extraction conditions used. Extractables testing of polymer resins is useful for material screening and in certain situations may replace routine component testing. PMID:25227309

  14. Fabrication process of a high temperature polymer matrix engine duct

    NASA Technical Reports Server (NTRS)

    Pratt, R. D.; Wilson, A. J.

    1985-01-01

    The process that was used in the molding of an advanced composite outer by-pass duct planned for the F404 engine is discussed. This duct was developed as a potential replacement for the existing titanium duct in order to reduce both the weight and cost of the duct. The composite duct is now going into the manufacturing technology portion of the program. The duct is fabricated using graphite cloth impregnated with the PMR-15 matrix system.

  15. A two-step flocculation process on oil sands tailings treatment using oppositely charged polymer flocculants.

    PubMed

    Lu, Qiuyi; Yan, Bin; Xie, Lei; Huang, Jun; Liu, Yang; Zeng, Hongbo

    2016-09-15

    Water management and treatment of mineral tailings and oil sands tailings are becoming critical challenges for the sustainable development of natural resources. Polymeric flocculants have been widely employed to facilitate the flocculation and settling of suspended fine solid particles in tailings, resulting in the separation of released water and solid sediments. In this study, a new flocculation process was developed for the treatment of oil sands tailings by using two oppositely charged polymers, i.e. an anionic polyacrylamide and a natural cationic biopolymer, chitosan. The new process was able to not only improve the clarity of supernatant after settling but also achieve a high settling efficiency. Treatment of the oil sands tailings using pure anionic polyacrylamide showed relatively high initial settling rate (ISR) of ~10.3m/h but with poor supernatant clarity (>1000NTU); while the treatment using pure cationic polymer resulted in clear supernatant (turbidity as low as 22NTU) but relatively low ISR of >2m/h. In the new flocculation process, the addition of anionic polyacrylamide to the tailings was followed by a cationic polymer, which showed both a high ISR (~7.7m/h) and a low turbidity (71NTU) of the supernatant. The flocculation mechanism was further investigated via the measurements of floc size, zeta potential and surface forces. The new flocculation process was revealed to include two steps: (1) bridging of fine solids by anionic polyacrylamide, and (2) further aggregation and flocculation mediated by charge neutralisation of the cationic polymer, which significantly eliminated the fine solids in the supernatants as well as increases floc size. Our results provide insights into the basic understanding of the interactions between polymer flocculants and solid particles in tailings treatment, as well as the development of novel tailings treatment technologies. PMID:27179318

  16. Interplay of formulation and process methodology on the extent of nifedipine molecular dispersion in polymers.

    PubMed

    Huang, Jingjun; Li, Ying; Wigent, Rodney J; Malick, Waseem A; Sandhu, Harpreet K; Singhal, Dharmendra; Shah, Navnit H

    2011-11-25

    The aim of this study is to evaluate effects of formulation and process technology on drug molecular dispersibility in solid dispersions (SDs). Nifedipine solid dispersions with ethylcellulose (EC) and/or Eudragit RL (RL) prepared by co-precipitation, co-evaporation, and fusion methods were characterized with FTIR, DSC, and XRPD for the content of nifedipine as molecular dispersion, amorphous and/or crystalline suspensions. A method was developed based on regular solution and Flory-Huggins theories to calculate drug-polymer interaction parameter in solid dispersion systems. A synergic effect of RL and EC on nifedipine molecular dispersibility in solid dispersions was observed. Increasing RL/EC ratio resulted in a higher degree of drug-polymer interaction that thermodynamically favored molecular dispersion, which, however, was counteracted by a corresponding decrease in the matrix glass transition point that kinetically favored phase-separation. Process methodology was found to play an important role in the formation of amorphous SD. The ranking of technologies with respect to the extent of molecular dispersion from high to low is fusion>co-evaporation>co-precipitation, wherein the solidification rate of polymeric solution and non-solvent effects were linked to kinetic entrapment of drug molecules in polymeric networks. Since nifedipine molecular dispersibility in EC/RL polymer(s) is a result of interplay between thermodynamic and kinetic factors, nifedipine molecular dispersions prepared for this study are thermodynamically metastable systems. To explore those supersaturation systems for use in drug delivery of poorly water soluble drugs, it is critical to balance drug-polymer interactions and matrix glass transition point and to consider a process technology with a fast solidification rate during formulation and process development of amorphous SD.

  17. A two-step flocculation process on oil sands tailings treatment using oppositely charged polymer flocculants.

    PubMed

    Lu, Qiuyi; Yan, Bin; Xie, Lei; Huang, Jun; Liu, Yang; Zeng, Hongbo

    2016-09-15

    Water management and treatment of mineral tailings and oil sands tailings are becoming critical challenges for the sustainable development of natural resources. Polymeric flocculants have been widely employed to facilitate the flocculation and settling of suspended fine solid particles in tailings, resulting in the separation of released water and solid sediments. In this study, a new flocculation process was developed for the treatment of oil sands tailings by using two oppositely charged polymers, i.e. an anionic polyacrylamide and a natural cationic biopolymer, chitosan. The new process was able to not only improve the clarity of supernatant after settling but also achieve a high settling efficiency. Treatment of the oil sands tailings using pure anionic polyacrylamide showed relatively high initial settling rate (ISR) of ~10.3m/h but with poor supernatant clarity (>1000NTU); while the treatment using pure cationic polymer resulted in clear supernatant (turbidity as low as 22NTU) but relatively low ISR of >2m/h. In the new flocculation process, the addition of anionic polyacrylamide to the tailings was followed by a cationic polymer, which showed both a high ISR (~7.7m/h) and a low turbidity (71NTU) of the supernatant. The flocculation mechanism was further investigated via the measurements of floc size, zeta potential and surface forces. The new flocculation process was revealed to include two steps: (1) bridging of fine solids by anionic polyacrylamide, and (2) further aggregation and flocculation mediated by charge neutralisation of the cationic polymer, which significantly eliminated the fine solids in the supernatants as well as increases floc size. Our results provide insights into the basic understanding of the interactions between polymer flocculants and solid particles in tailings treatment, as well as the development of novel tailings treatment technologies.

  18. The rheology and processing of “edge sheared” colloidal polymer opals

    SciTech Connect

    Wong, Hon Sum; Mackley, Malcolm Butler, Simon; Baumberg, Jeremy; Snoswell, David; Finlayson, Chris; Zhao, Qibin

    2014-03-15

    This paper is concerned with the rheology and processing of solvent-free core shell “polymer opals” that consist of a soft outer shell grafted to hard colloidal polymer core particles. Strong iridescent colors can be produced by shearing the material in a certain way that causes the initially disordered spheres to rearrange into ordered crystalline structures and produce colors by diffraction and interference of multiple light scattering, similar to gemstone opals. The basic linear viscoelastic rheology of a polymer opal sample was determined as a function of temperature, and the material was found to be highly viscoelastic at all tested temperatures. A Cambridge multipass rheometer was specifically modified in order to make controlled mechanical measurements of initially disordered polymer opal tapes that were sandwiched between protective polyethylene terephthalate sheets. Axial extension, simple shear, and a novel “edge shearing” geometry were all evaluated, and multiple successive experiments of the edge shearing test were carried out at different temperatures. The optical development of colloidal ordering, measured as optical opalescence, was quantified by spectroscopy using visible backscattered light. The development of opalescence was found to be sensitive to the geometry of deformation and a number of process variables suggesting a complex interaction of parameters that caused the opalescence. In order to identify aspects of the deformation mechanism of the edge shearing experiment, a separate series of in situ optical experiments were carried out and this helped indicate the extent of simple shear generated with each edge shear deformation. The results show that strong ordering can be induced by successive edge shearing deformation. The results are relevant to polymer opal rheology, processing, and mechanisms relating to ordering within complex viscoelastic fluids.

  19. Dithienobenzothiadiazole-based conjugated polymer: processing solvent-relied interchain aggregation and device performances in field-effect transistors and polymer solar cells.

    PubMed

    Huang, Jun; Zhu, Yongxiang; Chen, Junwu; Zhang, Lianjie; Peng, Junbiao; Cao, Yong

    2014-11-01

    DTfBT-Th(3), a new conjugated polymer based on dithienobenzothiadiazole and terthiophene, possesses a bandgap of ≈1.86 eV and a HOMO level of -5.27 eV. Due to strong interchain aggregation, DTfBT-Th(3) can not be well dissolved in chloro-benzene (CB) and o-dichlorobenzene (DCB) at room temperature (RT), but the polymer can be processed from hot CB and DCB solutions of ≈100 °C. In CB, with a lower solvation ability, a certain polymer chain aggregation can be preserved, even in hot solution. DTfBT-Th(3) displays a field-effect hole mobility of 0.55 cm(2) V(-1) s(-1) when fabricated from hot CB solution, which is higher than that of the device processed from hot DCB (0.16 cm(2) V(-1) s(-1) In DTfBT-Th(3) -based polymer solar cells, a good power conversion efficiency from 5.37% to 6.67% can be achieved with 150-300 nm thick active layers casted from hot CB solution, while the highest efficiency for hot DCB-processed solar cells is only 5.07%. The results demonstrate that using a solvent with a lower solvation ability, as a "wet control" process, is beneficial to preserve strong interchain aggregation of a conjugated polymer during solution processing, showing great potential to improve its performances in optoelectronic devices.

  20. Polymerization and processing of polymers in magnetic fields

    SciTech Connect

    Benicewicz, B.C.; Smith, M.E.; Douglas, E.P.

    1997-04-01

    Liquid crystalline thermosets (LCT`s) have become recognized over the past few years as an important class of materials. Numerous reports from the authors laboratory and others have described their synthesis and phase behavior. In particular, the authors have described important effects due to the orientation of the rodlike molecules in a liquid crystalline phase. They have found that curing rates are enhanced compared to reaction in an isotropic phase, and that the glass transition of the fully cured material can be significantly higher than the final cure temperature. For structural applications, orientation of LCT`s will allow maximum improvement in mechanical properties. A few studies have described use of magnetic fields to orient LCT`s. However, no measurements were made of the tensile properties of materials processed in magnetic fields. The authors have conducted experiments which describe the tensile modulus dependence of an LCT over the complete range of magnetic field strengths from 0 to 18 Tesla. Their work has focused on the system composed of the diglycidyl ether of dihydroxy-{alpha}-methylstilbene (DGE-DHAMS) cured with sulfanilamide (SAA).

  1. Process and Microstructure to Achieve Ultra-high Dielectric Constant in Ceramic-Polymer Composites

    PubMed Central

    Zhang, Lin; Shan, Xiaobing; Bass, Patrick; Tong, Yang; Rolin, Terry D.; Hill, Curtis W.; Brewer, Jeffrey C.; Tucker, Dennis S.; Cheng, Z.-Y.

    2016-01-01

    Influences of process conditions on microstructure and dielectric properties of ceramic-polymer composites are systematically studied using CaCu3Ti4O12 (CCTO) as filler and P(VDF-TrFE) 55/45 mol.% copolymer as the matrix by combining solution-cast and hot-pressing processes. It is found that the dielectric constant of the composites can be significantly enhanced–up to about 10 times – by using proper processing conditions. The dielectric constant of the composites can reach more than 1,000 over a wide temperature range with a low loss (tan δ ~ 10−1). It is concluded that besides the dense structure of composites, the uniform distribution of the CCTO particles in the matrix plays a key role on the dielectric enhancement. Due to the influence of the CCTO on the microstructure of the polymer matrix, the composites exhibit a weaker temperature dependence of the dielectric constant than the polymer matrix. Based on the results, it is also found that the loss of the composites at low temperatures, including room temperature, is determined by the real dielectric relaxation processes including the relaxation process induced by the mixing. PMID:27767184

  2. Sodium chloride methanol solution spin-coating process for bulk-heterojunction polymer solar cells

    NASA Astrophysics Data System (ADS)

    Liu, Tong-Fang; Hu, Yu-Feng; Deng, Zhen-Bo; Li, Xiong; Zhu, Li-Jie; Wang, Yue; Lv, Long-Feng; Wang, Tie-Ning; Lou, Zhi-Dong; Hou, Yan-Bing; Teng, Feng

    2016-08-01

    The sodium chloride methanol solution process is conducted on the conventional poly(3-hexylthiophene) (P3HT)/[6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) polymer bulk heterojunction solar cells. The device exhibits a power conversion efficiency of up to 3.36%, 18% higher than that of the device without the solution process. The measurements of the active layer by x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and ultraviolet photoelectron spectroscopy (UPS) indicate a slight phase separation in the vertical direction and a sodium chloride distributed island-like interface between the active layer and the cathode. The capacitance–voltage (C–V) and impedance spectroscopy measurements prove that the sodium chloride methanol process can reduce the electron injection barrier and improve the interfacial contact of polymer solar cells. Therefore, this one-step solution process not only optimizes the phase separation in the active layers but also forms a cathode buffer layer, which can enhance the generation, transport, and collection of photogenerated charge carriers in the device simultaneously. This work indicates that the inexpensive and non-toxic sodium chloride methanol solution process is an efficient one-step method for the low cost manufacturing of polymer solar cells. Project supported by the Fundamental Research Funds for the Central Universities, China (Grant No. 2014JBZ009) and the National Natural Science Foundation of China (Grant Nos. 61274063, 61377028, 61475014, and 61475017).

  3. Sodium chloride methanol solution spin-coating process for bulk-heterojunction polymer solar cells

    NASA Astrophysics Data System (ADS)

    Liu, Tong-Fang; Hu, Yu-Feng; Deng, Zhen-Bo; Li, Xiong; Zhu, Li-Jie; Wang, Yue; Lv, Long-Feng; Wang, Tie-Ning; Lou, Zhi-Dong; Hou, Yan-Bing; Teng, Feng

    2016-08-01

    The sodium chloride methanol solution process is conducted on the conventional poly(3-hexylthiophene) (P3HT)/[6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) polymer bulk heterojunction solar cells. The device exhibits a power conversion efficiency of up to 3.36%, 18% higher than that of the device without the solution process. The measurements of the active layer by x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and ultraviolet photoelectron spectroscopy (UPS) indicate a slight phase separation in the vertical direction and a sodium chloride distributed island-like interface between the active layer and the cathode. The capacitance-voltage (C-V) and impedance spectroscopy measurements prove that the sodium chloride methanol process can reduce the electron injection barrier and improve the interfacial contact of polymer solar cells. Therefore, this one-step solution process not only optimizes the phase separation in the active layers but also forms a cathode buffer layer, which can enhance the generation, transport, and collection of photogenerated charge carriers in the device simultaneously. This work indicates that the inexpensive and non-toxic sodium chloride methanol solution process is an efficient one-step method for the low cost manufacturing of polymer solar cells. Project supported by the Fundamental Research Funds for the Central Universities, China (Grant No. 2014JBZ009) and the National Natural Science Foundation of China (Grant Nos. 61274063, 61377028, 61475014, and 61475017).

  4. Interfacial and Electrode Modifications in P3HT:PC61BM based Organic Solar Cells: Devices, Processing and Characterization

    NASA Astrophysics Data System (ADS)

    Das, Sayantan

    The inexorable upsurge in world’s energy demand has steered the search for newer renewable energy sources and photovoltaics seemed to be one of the best alternatives for energy production. Among the various photovoltaic technologies that emerged, organic/polymer photovoltaics based on solution processed bulk-heterojunctions (BHJ) of semiconducting polymers has gained serious attention owing to the use of inexpensive light-weight materials, exhibiting high mechanical flexibility and compatibility with low temperature roll-to-roll manufacturing techniques on flexible substrates. The most widely studied material to date is the blend of regioregular P3HT and PC61BM used as donor and acceptor materials. The object of this study was to investigate and improve the performance/stability of the organic solar cells by use of inexpensive materials. In an attempt to enhance the efficiency of organic solar cells, we have demonstrated the use of hexamethyldisilazane (HMDS) modified indium tin oxide (ITO) electrode in bulk heterojunction solar cell structure The device studies showed a significant enhancement in the short-circuit current as well as in the shunt resistance on use of the hexamethyldisilazane (HMDS) layer. In another approach a p-type CuI hole-transport layer was utilized that could possibly replace the acidic PEDOT:PSS layer in the fabrication of high-efficiency solar cells. The device optimization was done by varying the concentration of CuI in the precursor solution which played an important role in the efficiency of the solar cell devices. Recently a substantial amount of research has been focused on identifying suitable interfacial layers in organic solar cells which has efficient charge transport properties. It was illustrated that a thin layer of silver oxide interfacial layer showed a 28% increase in power conversion efficiency in comparison to that of the control cell. The optoelectronic properties and morphological features of indium-free Zn

  5. A sacrificial process for fabrication of biodegradable polymer membranes with submicron thickness.

    PubMed

    Beardslee, Luke A; Stolwijk, Judith; Khaladj, Dimitrius A; Trebak, Mohamed; Halman, Justin; Torrejon, Karen Y; Niamsiri, Nuttawee; Bergkvist, Magnus

    2016-08-01

    A new sacrificial molding process using a single mask has been developed to fabricate ultrathin 2-dimensional membranes from several biocompatible polymeric materials. The fabrication process is similar to a sacrificial microelectromechanical systems (MEMS) process flow, where a mold is created from a material that can be coated with a biodegradable polymer and subsequently etched away, leaving behind a very thin polymer membrane. In this work, two different sacrificial mold materials, silicon dioxide (SiO2 ) and Liftoff Resist (LOR) were used. Three different biodegradable materials; polycaprolactone (PCL), poly(lactic-co-glycolic acid) (PLGA), and polyglycidyl methacrylate (PGMA), were chosen as model polymers. We demonstrate that this process is capable of fabricating 200-500 nm thin, through-hole polymer membranes with various geometries, pore-sizes and spatial features approaching 2.5 µm using a mold fabricated via a single contact photolithography exposure. In addition, the membranes can be mounted to support rings made from either SU8 or PCL for easy handling after release. Cell culture compatibility of the fabricated membranes was evaluated with human dermal microvascular endothelial cells (HDMECs) seeded onto the ultrathin porous membranes, where the cells grew and formed confluent layers with well-established cell-cell contacts. Furthermore, human trabecular meshwork cells (HTMCs) cultured on these scaffolds showed similar proliferation as on flat PCL substrates, further validating its compatibility. All together, these results demonstrated the feasibility of our sacrificial fabrication process to produce biocompatible, ultra-thin membranes with defined microstructures (i.e., pores) with the potential to be used as substrates for tissue engineering applications. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1192-1201, 2016. PMID:26079689

  6. Photophysical properties and photoisomerization processes of Methyl Red embedded in rigid polymer

    NASA Astrophysics Data System (ADS)

    Lee, Geon Joon; Kim, Dongho; Lee, Minyung

    1995-01-01

    The photophysical properties of Methyl Red molecules embedded in a poly(methyl methacrylate) (PMMA) matrix were investigated with photoinduced absorption, absorption kinetics, steady-state, and time-resolved luminescence spectroscopy. The excited singlet (S1) state lifetimes for trans and cis isomers of Methyl Red in PMMA at room temperature have been measured as 35 and 420 ps, respectively. The excited triplet (T1) state energy level and its lifetime at 77 K were also obtained. A slow trans-cis isomerization process having a time constant of a few hundred seconds was observed for the illuminated Methyl Red in rigid polymer. Based on measured photophysical properties and dynamic processes, an energy-level diagram for Methyl Red molecules in rigid polymer is introduced to explain these observations.

  7. Value-added processing of crude glycerol into chemicals and polymers.

    PubMed

    Luo, Xiaolan; Ge, Xumeng; Cui, Shaoqing; Li, Yebo

    2016-09-01

    Crude glycerol is a low-value byproduct which is primarily obtained from the biodiesel production process. Its composition is significantly different from that of pure glycerol. Crude glycerol usually contains various impurities, such as water, methanol, soap, fatty acids, and fatty acid methyl esters. Considerable efforts have been devoted to finding applications for converting crude glycerol into high-value products, such as biofuels, chemicals, polymers, and animal feed, to improve the economic viability of the biodiesel industry and overcome environmental challenges associated with crude glycerol disposal. This article reviews recent advances of biological and chemical technologies for value-added processing of crude glycerol into chemicals and polymers, and provides strategies for addressing production challenges. PMID:27004448

  8. Effect of dopant nanoparticles on reorientation process in polymer-dispersed liquid crystals

    NASA Astrophysics Data System (ADS)

    Zobov, K. V.; Zharkova, G. M.; Syzrantsev, V. V.

    2016-01-01

    The analysis of the experimental data of the nanoscale powders application for doping polymer-dispersed liquid crystals (PDLC) was represented in this work. A model based on the separation of the liquid crystals reorientation process on the surface mode and the volume mode was proposed and tested. In the research the wide-spread model mixture PDLC were used. But alumina nanoparticles were the distinctive ones obtained by electron beam evaporation. The proposed model allowed to conclude that the nanoparticles localization at the surface of the droplets (as in the Pickering emulsion) lead to the variation of the connection force between the liquid crystals and the polymer. The effect of nanoparticles resulted in an acceleration of the reorientation process near the surface when the control field is turned on and in a deceleration when it is turned off. The effect for the different size particles was confirmed.

  9. Influence of process variables on essential oil microcapsule properties by carbohydrate polymer-protein blends.

    PubMed

    Banerjee, Subham; Chattopadhyay, Pronobesh; Ghosh, Animesh; Goyary, Danswrang; Karmakar, Sanjeev; Veer, Vijay

    2013-04-01

    Carbohydrate polymer-protein blends Zanthoxylum limonella oil (ZLO) loaded microcapsules were prepared by multiple emulsion solvent evaporation technology and the influence of various processing variables on the properties of ZLO loaded microcapsules were examined systematically. It was found that the internal aqueous alginate phase volume, external aqueous gelatin phase volume and concentration of surfactant in external aqueous gelatin phase have a significant influence on microcapsules properties. The essential oil-loaded microcapsules were smooth and spherical in shape as revealed by scanning electron micrograph. Results of Fourier transform infrared (FTIR) spectroscopy indicated stable character and showed the absence of chemical interaction between the microencapsulated oil and carbohydrate polymer-protein blends. Differential scanning calorimetry (DSC) study revealed the antioxidant nature of ZLO in the microcapsules. The release rate of ZLO loaded microcapsules was analyzed by UV-vis spectrophotometer. 83.80% of oil encapsulation efficiency was obtained depending upon the processing variables. Thus, proper control of the processing variables involved in this technology could allow effective incorporation of essential oil into the core of the carbohydrate polymer-protein blends matrix.

  10. Simple one-step process for immobilization of biomolecules on polymer substrates based on surface-attached polymer networks.

    PubMed

    Rendl, Martin; Bönisch, Andreas; Mader, Andreas; Schuh, Kerstin; Prucker, Oswald; Brandstetter, Thomas; Rühe, Jürgen

    2011-05-17

    For the miniaturization of biological assays, especially for the fabrication of microarrays, immobilization of biomolecules at the surfaces of the chips is the decisive factor. Accordingly, a variety of binding techniques have been developed over the years to immobilize DNA or proteins onto such substrates. Most of them require rather complex fabrication processes and sophisticated surface chemistry. Here, a comparatively simple immobilization technique is presented, which is based on the local generation of small spots of surface attached polymer networks. Immobilization is achieved in a one-step procedure: probe molecules are mixed with a photoactive copolymer in aqueous buffer, spotted onto a solid support, and cross-linked as well as bound to the substrate during brief flood exposure to UV light. The described procedure permits spatially confined surface functionalization and allows reliable binding of biological species to conventional substrates such as glass microscope slides as well as various types of plastic substrates with comparable performance. The latter also permits immobilization on structured, thermoformed substrates resulting in an all-plastic biochip platform, which is simple and cheap and seems to be promising for a variety of microdiagnostic applications. PMID:21491877

  11. Simple one-step process for immobilization of biomolecules on polymer substrates based on surface-attached polymer networks.

    PubMed

    Rendl, Martin; Bönisch, Andreas; Mader, Andreas; Schuh, Kerstin; Prucker, Oswald; Brandstetter, Thomas; Rühe, Jürgen

    2011-05-17

    For the miniaturization of biological assays, especially for the fabrication of microarrays, immobilization of biomolecules at the surfaces of the chips is the decisive factor. Accordingly, a variety of binding techniques have been developed over the years to immobilize DNA or proteins onto such substrates. Most of them require rather complex fabrication processes and sophisticated surface chemistry. Here, a comparatively simple immobilization technique is presented, which is based on the local generation of small spots of surface attached polymer networks. Immobilization is achieved in a one-step procedure: probe molecules are mixed with a photoactive copolymer in aqueous buffer, spotted onto a solid support, and cross-linked as well as bound to the substrate during brief flood exposure to UV light. The described procedure permits spatially confined surface functionalization and allows reliable binding of biological species to conventional substrates such as glass microscope slides as well as various types of plastic substrates with comparable performance. The latter also permits immobilization on structured, thermoformed substrates resulting in an all-plastic biochip platform, which is simple and cheap and seems to be promising for a variety of microdiagnostic applications.

  12. Optimised process and formulation conditions for extended release dry polymer powder-coated pellets.

    PubMed

    Terebesi, Ildikó; Bodmeier, Roland

    2010-05-01

    The objective of this study was to improve the film formation and permeability characteristics of extended release ethylcellulose coatings prepared by dry polymer powder coating for the release of drugs of varying solubility. Ethylcellulose (7 and 10 cp viscosity grades) and Eudragit(R) RS were used for dry powder coating of pellets in a fluidised bed ball coater. Pre-plasticised ethylcellulose powder was prepared by spray-drying aqueous ethylcellulose dispersions (Surelease(R) and Aquacoat(R)) or by hot melt extrusion/cryogenic grinding of plasticised ethylcellulose. Chlorpheniramine maleate and theophylline were used as model drugs of different solubilities. The film formation process, polymeric films and coated pellets were characterised by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), scanning electron microscopy (SEM) and dissolution testing. Film formation and extended drug release was achieved with ethylcellulose, a polymer with a high glass transition temperature (T(g)) without the use of water, which is usually required in dry powder coating. DMA-measurements revealed that plasticised ethylcellulose had a modulus of elasticity (E') similar to the low T(g) Eudragit(R) RS. With increasing plasticiser concentration, the T(g) of ethylcellulose was reduced and the mechanical properties improved, thus facilitating coalescence of the polymer particles. SEM-pictures revealed the formation of a dense, homogeneous film. The lower viscosity grade ethylcellulose (7 cp) resulted in better film formation than the higher viscosity grade (10 cp) and required less stringent curing conditions. Successful extended release ethylcellulose coatings were also obtained by coating with pre-plasticised spray-dried ethylcellulose powders as an alternative to the separate application of pure ethylcellulose powder and plasticiser. The permeability of the extended release coating could be controlled by using powder blends of ethylcellulose with the

  13. Fabrication of conductive polymer nanofibers through SWNT supramolecular functionalization and aqueous solution processing

    NASA Astrophysics Data System (ADS)

    Naeem, Fahim; Prestayko, Rachel; Saem, Sokunthearath; Nowicki, Lauren; Imit, Mokhtar; Adronov, Alex; Moran-Mirabal, Jose M.

    2015-10-01

    Polymeric thin films and nanostructured composites with excellent electrical properties are required for the development of advanced optoelectronic devices, flexible electronics, wearable sensors, and tissue engineering scaffolds. Because most polymers available for fabrication are insulating, one of the biggest challenges remains the preparation of inexpensive polymer composites with good electrical conductivity. Among the nanomaterials used to enhance composite performance, single walled carbon nanotubes (SWNTs) are ideal due to their unique physical and electrical properties. Yet, a barrier to their widespread application is that they do not readily disperse in solvents traditionally used for polymer processing. In this study, we employed supramolecular functionalization of SWNTs with a conjugated polyelectrolyte as a simple approach to produce stable aqueous nanotube suspensions, that could be effortlessly blended with the polymer poly(ethyleneoxide) (PEO). The homogeneous SWNT:PEO mixtures were used to fabricate conductive thin films and nanofibers with improved conductivities through drop casting and electrospinning. The physical characterization of electrospun nanofibers through Raman spectroscopy and SEM revealed that the SWNTs were uniformly incorporated throughout the composites. The electrical characterization of SWNT:PEO thin films allowed us to assess their conductivity and establish a percolation threshold of 0.1 wt% SWNT. Similarly, measurement of the nanofiber conductivity showed that the electrospinning process improved the contact between nanotube complexes, resulting in conductivities in the S m-1 range with much lower weight loading of SWNTs than their thin film counterparts. The methods reported for the fabrication of conductive nanofibers are simple, inexpensive, and enable SWNT processing in aqueous solutions, and offer great potential for nanofiber use in applications involving flexible electronics, sensing devices, and tissue engineering

  14. Fabrication of conductive polymer nanofibers through SWNT supramolecular functionalization and aqueous solution processing.

    PubMed

    Naeem, Fahim; Prestayko, Rachel; Saem, Sokunthearath; Nowicki, Lauren; Imit, Mokhtar; Adronov, Alex; Moran-Mirabal, Jose M

    2015-10-01

    Polymeric thin films and nanostructured composites with excellent electrical properties are required for the development of advanced optoelectronic devices, flexible electronics, wearable sensors, and tissue engineering scaffolds. Because most polymers available for fabrication are insulating, one of the biggest challenges remains the preparation of inexpensive polymer composites with good electrical conductivity. Among the nanomaterials used to enhance composite performance, single walled carbon nanotubes (SWNTs) are ideal due to their unique physical and electrical properties. Yet, a barrier to their widespread application is that they do not readily disperse in solvents traditionally used for polymer processing. In this study, we employed supramolecular functionalization of SWNTs with a conjugated polyelectrolyte as a simple approach to produce stable aqueous nanotube suspensions, that could be effortlessly blended with the polymer poly(ethyleneoxide) (PEO). The homogeneous SWNT:PEO mixtures were used to fabricate conductive thin films and nanofibers with improved conductivities through drop casting and electrospinning. The physical characterization of electrospun nanofibers through Raman spectroscopy and SEM revealed that the SWNTs were uniformly incorporated throughout the composites. The electrical characterization of SWNT:PEO thin films allowed us to assess their conductivity and establish a percolation threshold of 0.1 wt% SWNT. Similarly, measurement of the nanofiber conductivity showed that the electrospinning process improved the contact between nanotube complexes, resulting in conductivities in the S m(-1) range with much lower weight loading of SWNTs than their thin film counterparts. The methods reported for the fabrication of conductive nanofibers are simple, inexpensive, and enable SWNT processing in aqueous solutions, and offer great potential for nanofiber use in applications involving flexible electronics, sensing devices, and tissue engineering

  15. Simulation of the temperature distribution in the selective beam melting process for polymer material

    SciTech Connect

    Riedlbauer, D. E-mail: julia.mergheim@ltm.uni-erlangen.de Mergheim, J. E-mail: julia.mergheim@ltm.uni-erlangen.de Steinmann, P. E-mail: julia.mergheim@ltm.uni-erlangen.de

    2014-05-15

    In the present contribution the temperature distribution in the selective beam melting process for polymer materials is simulated to better understand the influence of process parameters on the properties of the produced part. The basis for the developed simulation tool is the nonlinear heat equation including temperature dependent functions for the heat capacity and the heat conduction which were obtained by experimental measurements. The effect of latent heat occurring in the process is also taken into account. The heat equation is discretized in time and space where a Runge-Kutta method of Radau IIA type is used for time integration. An adaptive finite element method is applied for the discretization in space and the model is implemented into the finite element library deal.II. The heat and cooling rate as important process parameters are simulated for different beam velocities. The ability for computing these process parameters makes the simulation tool suited for optimizing the process management of selective beam melting plants.

  16. A new multiscale modeling method for simulating the loss processes in polymer solar cell nanodevices.

    PubMed

    Pershin, Anton; Donets, Sergii; Baeurle, Stephan A

    2012-05-21

    The photoelectric power conversion efficiency of polymer solar cells is till now, compared to conventional inorganic solar cells, still relatively low with maximum values ranging from 7% to 8%. This essentially relates to the existence of exciton and charge carrier loss phenomena, reducing the performance of polymer solar cells significantly. In this paper we introduce a new computer simulation technique, which permits to explore the causes of the occurrence of such phenomena at the nanoscale and to design new photovoltaic materials with optimized opto-electronic properties. Our approach consists in coupling a mesoscopic field-theoretic method with a suitable dynamic Monte Carlo algorithm, to model the elementary photovoltaic processes. Using this algorithm, we investigate the influence of structural characteristics and different device conditions on the exciton generation and charge transport efficiencies in case of a novel nanostructured polymer blend. More specifically, we find that the disjunction of continuous percolation paths leads to the creation of dead ends, resulting in charge carrier losses through charge recombination. Moreover, we observe that defects are characterized by a low exciton dissociation efficiency due to a high charge accumulation, counteracting the charge generation process. From these observations, we conclude that both the charge carrier loss and the exciton loss phenomena lead to a dramatic decrease in the internal quantum efficiency. Finally, by analyzing the photovoltaic behavior of the nanostructures under different circuit conditions, we demonstrate that charge injection significantly determines the impact of the defects on the solar cell performance.

  17. A new multiscale modeling method for simulating the loss processes in polymer solar cell nanodevices

    NASA Astrophysics Data System (ADS)

    Pershin, Anton; Donets, Sergii; Baeurle, Stephan A.

    2012-05-01

    The photoelectric power conversion efficiency of polymer solar cells is till now, compared to conventional inorganic solar cells, still relatively low with maximum values ranging from 7% to 8%. This essentially relates to the existence of exciton and charge carrier loss phenomena, reducing the performance of polymer solar cells significantly. In this paper we introduce a new computer simulation technique, which permits to explore the causes of the occurrence of such phenomena at the nanoscale and to design new photovoltaic materials with optimized opto-electronic properties. Our approach consists in coupling a mesoscopic field-theoretic method with a suitable dynamic Monte Carlo algorithm, to model the elementary photovoltaic processes. Using this algorithm, we investigate the influence of structural characteristics and different device conditions on the exciton generation and charge transport efficiencies in case of a novel nanostructured polymer blend. More specifically, we find that the disjunction of continuous percolation paths leads to the creation of dead ends, resulting in charge carrier losses through charge recombination. Moreover, we observe that defects are characterized by a low exciton dissociation efficiency due to a high charge accumulation, counteracting the charge generation process. From these observations, we conclude that both the charge carrier loss and the exciton loss phenomena lead to a dramatic decrease in the internal quantum efficiency. Finally, by analyzing the photovoltaic behavior of the nanostructures under different circuit conditions, we demonstrate that charge injection significantly determines the impact of the defects on the solar cell performance.

  18. Solution-Processed p-Dopant as Interlayer in Polymer Solar Cells.

    PubMed

    Guillain, F; Endres, J; Bourgeois, L; Kahn, A; Vignau, L; Wantz, G

    2016-04-13

    We report here an original approach to dope the semiconducting polymer-metal interface in an inverted bulk-heterojunction (BHJ) organic solar cell. Solution-processed 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), is deposited on top of a P3HT:PC61BM layer before deposition of the top electrode. Doping of P3HT by F4-TCNQ occurs after thermally induced diffusion at 100 °C of the latter into the BHJ. Diffusion and doping are evidenced by XPS and UV-vis-NIR absorption. XPS highlights the decrease in Fluorine concentration on top of the BHJ after annealing. In the same time, a charge transfer band attributed to doping is observed in the UV-vis-NIR absorption spectrum. Inverted polymer solar cells using solution-processed F4-TCNQ exhibit power conversion efficiency of nearly 3.5% after annealing. This simple and efficient approach, together with the low annealing temperature required to allow diffusion and doping, leads to standard efficiency P3HT:PC61BM polymer solar cells, which are suitable for printing on plastic flexible substrate.

  19. Continuously graded extruded polymer composites for energetic applications fabricated using twin-screw extrusion processing technology

    NASA Astrophysics Data System (ADS)

    Gallant, Frederick M.

    A novel method of fabricating functionally graded extruded composite materials is proposed for propellant applications using the technology of continuous processing with a Twin-Screw Extruder. The method is applied to the manufacturing of grains for solid rocket motors in an end-burning configuration with an axial gradient in ammonium perchlorate volume fraction and relative coarse/fine particle size distributions. The fabrication of functionally graded extruded polymer composites with either inert or energetic ingredients has yet to be investigated. The lack of knowledge concerning the processing of these novel materials has necessitated that a number of research issues be addressed. Of primary concern is characterizing and modeling the relationship between the extruder screw geometry, transient processing conditions, and the gradient architecture that evolves in the extruder. Recent interpretations of the Residence Time Distributions (RTDs) and Residence Volume Distributions (RVDs) for polymer composites in the TSE are used to develop new process models for predicting gradient architectures in the direction of extrusion. An approach is developed for characterizing the sections of the extrudate using optical, mechanical, and compositional analysis to determine the gradient architectures. The effects of processing on the burning rate properties of extruded energetic polymer composites are characterized for homogeneous formulations over a range of compositions to determine realistic gradient architectures for solid rocket motor applications. The new process models and burning rate properties that have been characterized in this research effort will be the basis for an inverse design procedure that is capable of determining gradient architectures for grains in solid rocket motors that possess tailored burning rate distributions that conform to user-defined performance specifications.

  20. Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

    NASA Technical Reports Server (NTRS)

    Cox, Sarah B.; Lui, Donovan; Gou, Jihua

    2014-01-01

    The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, which allows a shape to be formed prior to the cure, and is then pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Basalt fibers are used for the reinforcement in the composite system. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material.

  1. Impact of heating method on the flocculation process using thermosensitive polymer.

    PubMed

    Lemanowicz, Marcin; Kuźnik, Wojciech; Gibas, Mirosław; Dzido, Grzegorz; Gierczycki, Andrzej

    2012-09-01

    The impact of suspension heating method on the flocculation process using thermosensitive polymer is reported in this paper. In experiments a model suspension of chalk in RO water (purified by Reverse Osmosis) was destabilized using a copolymer of N-isopropylacrylamide (NIPAM) and cationic diallyldimethyl ammonium chloride (DADMAC). The measurements were made using a laboratory setup consisting of a mixing tank with four baffles, Rushton turbine, laser particle sizer Analysette 22 by Fritsch and a system of pump and thermostating devices. Two different modes of heating were used. In the first case the temperature of the system was gently raised above the Lower Critical Solution Temperature (LCST) using an electrical heater placed inside the tank, while in the second case the system temperature was rapidly raised by an injection of hot water directly into the tank. It was proven that heating method as well as the polymer concentration was crucial to the shape and size of created flocs.

  2. Impact of heating method on the flocculation process using thermosensitive polymer.

    PubMed

    Lemanowicz, Marcin; Kuźnik, Wojciech; Gibas, Mirosław; Dzido, Grzegorz; Gierczycki, Andrzej

    2012-09-01

    The impact of suspension heating method on the flocculation process using thermosensitive polymer is reported in this paper. In experiments a model suspension of chalk in RO water (purified by Reverse Osmosis) was destabilized using a copolymer of N-isopropylacrylamide (NIPAM) and cationic diallyldimethyl ammonium chloride (DADMAC). The measurements were made using a laboratory setup consisting of a mixing tank with four baffles, Rushton turbine, laser particle sizer Analysette 22 by Fritsch and a system of pump and thermostating devices. Two different modes of heating were used. In the first case the temperature of the system was gently raised above the Lower Critical Solution Temperature (LCST) using an electrical heater placed inside the tank, while in the second case the system temperature was rapidly raised by an injection of hot water directly into the tank. It was proven that heating method as well as the polymer concentration was crucial to the shape and size of created flocs. PMID:22658925

  3. Improved cost-effectiveness of the block co-polymer anneal process for DSA

    NASA Astrophysics Data System (ADS)

    Pathangi, Hari; Stokhof, Maarten; Knaepen, Werner; Vaid, Varun; Mallik, Arindam; Chan, Boon Teik; Vandenbroeck, Nadia; Maes, Jan Willem; Gronheid, Roel

    2016-04-01

    This manuscript first presents a cost model to compare the cost of ownership of DSA and SAQP for a typical front end of line (FEoL) line patterning exercise. Then, we proceed to a feasibility study of using a vertical furnace to batch anneal the block co-polymer for DSA applications. We show that the defect performance of such a batch anneal process is comparable to the process of record anneal methods. This helps in increasing the cost benefit for DSA compared to the conventional multiple patterning approaches.

  4. Manufacture of porous biodegradable polymer conduits by an extrusion process for guided tissue regeneration

    NASA Technical Reports Server (NTRS)

    Widmer, M. S.; Gupta, P. K.; Lu, L.; Meszlenyi, R. K.; Evans, G. R.; Brandt, K.; Savel, T.; Gurlek, A.; Patrick, C. W. Jr; Mikos, A. G.; McIntire, L. V. (Principal Investigator)

    1998-01-01

    We have fabricated porous, biodegradable tubular conduits for guided tissue regeneration using a combined solvent casting and extrusion technique. The biodegradable polymers used in this study were poly(DL-lactic-co-glycolic acid) (PLGA) and poly(L-lactic acid) (PLLA). A polymer/salt composite was first prepared by a solvent casting process. After drying, the composite was extruded to form a tubular construct. The salt particles in the construct were then leached out leaving a conduit with an open-pore structure. PLGA was studied as a model polymer to analyze the effects of salt weight fraction, salt particle size, and processing temperature on porosity and pore size of the extruded conduits. The porosity and pore size were found to increase with increasing salt weight fraction. Increasing the salt particle size increased the pore diameter but did not affect the porosity. High extrusion temperatures decreased the pore diameter without altering the porosity. Greater decrease in molecular weight was observed for conduits manufactured at higher temperatures. The mechanical properties of both PLGA and PLLA conduits were tested after degradation in vitro for up to 8 weeks. The modulus and failure strength of PLLA conduits were approximately 10 times higher than those of PLGA conduits. Failure strain was similar for both conduits. After degradation for 8 weeks, the molecular weights of the PLGA and PLLA conduits decreased to 38% and 43% of the initial values, respectively. However, both conduits maintained their shape and did not collapse. The PLGA also remained amorphous throughout the time course, while the crystallinity of PLLA increased from 5.2% to 11.5%. The potential of seeding the conduits with cells for transplantation or with biodegradable polymer microparticles for drug delivery was also tested with dyed microspheres. These porous tubular structures hold great promise for the regeneration of tissues which require tubular scaffolds such as peripheral nerve

  5. Functionalization of polymers using an atmospheric plasma jet in a fluidized bed reactor and the impact on SLM-processes

    SciTech Connect

    Sachs, M. Schmitt, A. Schmidt, J. Peukert, W. Wirth, K-E

    2014-05-15

    In order to improve thermoplastics (e.g. Polyamide, Polypropylene and Polyethylene) for Selective Laser Beam Melting (SLM) processes a new approach to functionalize temperature sensitive polymer powders in a large scale is investigated. This is achieved by combining an atmospheric pressure plasma jet and a fluidized bed reactor. Using pressurized air as the plasma gas, radicals like OH* are created. The functionalization leads to an increase of the hydrophilicity of the treated polymer powder without changing the bulk properties. Using the polymers in a SLM process to build single layers of melted material leads to an improvement of the melted layers.

  6. Functionalization of polymers using an atmospheric plasma jet in a fluidized bed reactor and the impact on SLM-processes

    NASA Astrophysics Data System (ADS)

    Sachs, M.; Schmitt, A.; Schmidt, J.; Peukert, W.; Wirth, K.-E.

    2014-05-01

    In order to improve thermoplastics (e.g. Polyamide, Polypropylene and Polyethylene) for Selective Laser Beam Melting (SLM) processes a new approach to functionalize temperature sensitive polymer powders in a large scale is investigated. This is achieved by combining an atmospheric pressure plasma jet and a fluidized bed reactor. Using pressurized air as the plasma gas, radicals like OH* are created. The functionalization leads to an increase of the hydrophilicity of the treated polymer powder without changing the bulk properties. Using the polymers in a SLM process to build single layers of melted material leads to an improvement of the melted layers.

  7. Optimising Drug Solubilisation in Amorphous Polymer Dispersions: Rational Selection of Hot-melt Extrusion Processing Parameters.

    PubMed

    Li, Shu; Tian, Yiwei; Jones, David S; Andrews, Gavin P

    2016-02-01

    The aim of this article was to construct a T-ϕ phase diagram for a model drug (FD) and amorphous polymer (Eudragit® EPO) and to use this information to understand the impact of how temperature-composition coordinates influenced the final properties of the extrudate. Defining process boundaries and understanding drug solubility in polymeric carriers is of utmost importance and will help in the successful manufacture of new delivery platforms for BCS class II drugs. Physically mixed felodipine (FD)-Eudragit(®) EPO (EPO) binary mixtures with pre-determined weight fractions were analysed using DSC to measure the endset of melting and glass transition temperature. Extrudates of 10 wt% FD-EPO were processed using temperatures (110°C, 126°C, 140°C and 150°C) selected from the temperature-composition (T-ϕ) phase diagrams and processing screw speed of 20, 100 and 200rpm. Extrudates were characterised using powder X-ray diffraction (PXRD), optical, polarised light and Raman microscopy. To ensure formation of a binary amorphous drug dispersion (ADD) at a specific composition, HME processing temperatures should at least be equal to, or exceed, the corresponding temperature value on the liquid-solid curve in a F-H T-ϕ phase diagram. If extruded between the spinodal and liquid-solid curve, the lack of thermodynamic forces to attain complete drug amorphisation may be compensated for through the use of an increased screw speed. Constructing F-H T-ϕ phase diagrams are valuable not only in the understanding drug-polymer miscibility behaviour but also in rationalising the selection of important processing parameters for HME to ensure miscibility of drug and polymer.

  8. Rapid prototyping of biodegradable microneedle arrays by integrating CO2 laser processing and polymer molding

    NASA Astrophysics Data System (ADS)

    Tu, K. T.; Chung, C. K.

    2016-06-01

    An integrated technology of CO2 laser processing and polymer molding has been demonstrated for the rapid prototyping of biodegradable poly-lactic-co-glycolic acid (PLGA) microneedle arrays. Rapid and low-cost CO2 laser processing was used for the fabrication of a high-aspect-ratio microneedle master mold instead of conventional time-consuming and expensive photolithography and etching processes. It is crucial to use flexible polydimethylsiloxane (PDMS) to detach PLGA. However, the direct CO2 laser-ablated PDMS could generate poor surfaces with bulges, scorches, re-solidification and shrinkage. Here, we have combined the polymethyl methacrylate (PMMA) ablation and two-step PDMS casting process to form a PDMS female microneedle mold to eliminate the problem of direct ablation. A self-assembled monolayer polyethylene glycol was coated to prevent stiction between the two PDMS layers during the peeling-off step in the PDMS-to-PDMS replication. Then the PLGA microneedle array was successfully released by bending the second-cast PDMS mold with flexibility and hydrophobic property. The depth of the polymer microneedles can range from hundreds of micrometers to millimeters. It is linked to the PMMA pattern profile and can be adjusted by CO2 laser power and scanning speed. The proposed integration process is maskless, simple and low-cost for rapid prototyping with a reusable mold.

  9. Structure/property development in aPET during large strain, solid phase polymer processing

    NASA Astrophysics Data System (ADS)

    Martin, Peter; Mohamed, Raja Roslan Raja

    2015-12-01

    Amorphous Polyethylene terephthalate (aPET) is increasingly of interest for the polymer packaging industry due to its blend of excellent mechanical properties and most importantly its ease of recyclability. Among the major commercial polymers it is almost unique in the degree of improvement in mechanical properties that can be obtained through process-induced strain. For many years these unique properties have been very successfully exploited in the injection stretch blow molding process, where it is deliberately stretched to very large strains using extremely high pressures. However, the material is now also being used in much lower pressure processes such as thermoforming where its properties are often not fully exploited. In this work the change in structure and properties of aPET with strain is systematically investigated using a high speed biaxial stretching machine. The aim was to demonstrate how the properties of the material could be controlled by large strain, high temperature biaxial stretching processes such as thermoforming and blow molding. The results show that property changes in the material are driven by orientation and the onset of rapid strain hardening at large strains. This in turn is shown to vary strongly with process-induced parameters such as the strain rate and the mode and magnitude of biaxial deformation.

  10. Modeling and flow analysis of pure nylon polymer for injection molding process

    NASA Astrophysics Data System (ADS)

    Nuruzzaman, D. M.; Kusaseh, N.; Basri, S.; Oumer, A. N.; Hamedon, Z.

    2016-02-01

    In the production of complex plastic parts, injection molding is one of the most popular industrial processes. This paper addresses the modeling and analysis of the flow process of the nylon (polyamide) polymer for injection molding process. To determine the best molding conditions, a series of simulations are carried out using Autodesk Moldflow Insight software and the processing parameters are adjusted. This mold filling commercial software simulates the cavity filling pattern along with temperature and pressure distributions in the mold cavity. In the modeling, during the plastics flow inside the mold cavity, different flow parameters such as fill time, pressure, temperature, shear rate and warp at different locations in the cavity are analyzed. Overall, this Moldflow is able to perform a relatively sophisticated analysis of the flow process of pure nylon. Thus the prediction of the filling of a mold cavity is very important and it becomes useful before a nylon plastic part to be manufactured.

  11. Studies in process modeling, design, monitoring, and control, with applications to polymer composites manufacturing

    NASA Astrophysics Data System (ADS)

    Srinivasagupta, Deepak

    2002-01-01

    High material and manufacturing costs have hindered the introduction of advanced polymer composite materials into mainstream civilian applications such as automotive. Even though high-fidelity models for several polymer composite manufacturing processes have become available over the past several years and offer significant benefits in manufacturing cost reduction, concerns about their inflexibility and maintenance has adversely affected their widespread usage. This research seeks to advance process modeling and design in polymer composites manufacturing to address these concerns. Other more general issues in measurement validation and distributed control are also addressed. Using a rigorous 3-D model of the injected pultrusion (IP) process validated recently, an algorithm was developed for process and equipment design with integrated economic, operability and environmental considerations. The optimum design promised enhanced throughput as well as reduction in the time and expenses of the current purely experimental approaches. Scale-up issues in IP were analyzed, and refinements to overcome some drawbacks in the model were suggested. The process model was then extended to simulate the co-injection resin transfer molding (CIRTM) process used for manufacture of foam-core sandwich composites. A 1-D isothermal model for real-time control was also developed. Process optimization using these models and experimental parametric studies increased the debond fracture toughness of sandwiches by 78% over current technology. To ensure the availability of validated measurements from process instrumentation, a novel in-situ sensor modeling approach to sensor validation was proposed. Both active and passive, time and frequency domain techniques were developed, and experimentally verified using temperature and flow sensors. A model-based dynamic estimator to predict the true measurement online was also validated. The effect of network communication delay on stability and control

  12. Tandem oxidative processes catalyzed by polymer-incarcerated multimetallic nanoclusters with molecular oxygen.

    PubMed

    Miyamura, Hiroyuki; Kobayashi, Shū

    2014-04-15

    Heterogeneous catalysis and one-pot tandem reactions are key for efficient and practical organic syntheses and for green and sustainable chemistry. Heterogeneous catalysts can be recovered and reused. These catalysts can be applied to efficient systems, such as continuous-flow systems. Tandem reactions often proceed via highly reactive but unstable intermediates. Tandem reactions do not require workup or much purification of the intermediate. This Account summarizes recent developments that we have made in the field of multifunctional heterogeneous metal nanocluster catalysts for use in tandem reactions based on aerobic oxidation reactions as key processes. We constructed our heterogeneous metal nanoclusters via two important procedures--microencapsulation and cross-linking--using polystyrene-based copolymers with cross-linking moieties. These frameworks can efficiently stabilize small metal nanoclusters to maintain high catalytic activity without aggregation and leaching of nanoclusters. Aggregation and leaching are prevented by weak but multiple interactions between metal nanocluster surfaces and benzene rings in the copolymer as well as by the physical envelopment of cross-linked polymer backbones. Small nanoclusters, including multimetallic alloy clusters (nanoalloys), can be "imprisoned" into these cross-linked polymer composites. The term we use for these processes is polymer incarceration. Direct oxidative esterifications were achieved with polymer-incarcerated (PI) Au nanocluster catalysts. Amides were synthesized from alcohols and amines under aerobic oxidative conditions with PI bimetallic nanocluster catalysts composed of Au and Fe-group metals that formed separated nanoclusters rather than alloys. Oxidative lactam formation from amino alcohols was also achieved. On the other hand, imines could be prepared selectively from alcohols and amines with PI Au-Pd bimetallic nanoclusters. We also achieved the integration of the aerobic oxidation of allylic

  13. Processing and properties of ceramic matrix-polymer composites for dental applications

    NASA Astrophysics Data System (ADS)

    Huang, Hsuan Yao

    The basic composite structure of natural hard tissue was used to guide the design and processing of dental restorative materials. The design incorporates the methodology of using inorganic minerals as the main structural phase reinforced with a more ductile but tougher organic phase. Ceramic-polymer composites were prepared by slip casting a porous ceramic structure, heating and chemical treating the porous preform, infiltrating with monomer and then curing. The three factors that determined the mechanical properties of alumina-polymer composites were the type of polymer used, the method of silane treatments, and the type of bond between particles in the porous preforms. Without the use of silane coupling agents, the composites were measured to have a lower strength. The composite with a more "flexible" porous alumina network had a greater ability to plastically dissipate the energy of propagating cracks. However, the aggressive nature of the alumina particles on opposing enamel requires that these alumina-polymer composites have a wear compatible coating for practical application. A route to dense bioactive apatite wollastonite glass ceramics (AWGC)-polymer composites was developed. The problems associated with glass dissolution into the aqueous medium for slip casting were overcome with the use of silane. The role of heating rate and development of ceramic compact microstructure on composite properties was explored. In general, if isothermal heating was not applied, decreasing heating rate increased glass crystallinity and particle-particle fusion, but decreased pore volume. Also composite strength and fracture toughness decreased while modulus and hardness increased with decreasing heating rate. If isothermal heating was applied, glass crystallinity, pore content, and composite mechanical properties showed relatively little change regardless of the initial heating rate. The potential of AWGC-polymer composites for dental and implant applications was explored

  14. Large area ceramic thin films on plastics: A versatile route via solution processing

    SciTech Connect

    Kozuka, H.; Yamano, A.; Uchiyama, H.; Takahashi, M.; Fukui, T.; Yoki, M.; Akase, T.

    2012-01-01

    A new general route for large area, submicron thick ceramic thin films (crystalline metal oxide thin films) on plastic substrates is presented, where the crystallization of films is guaranteed by a firing process. Gel films are deposited on silicon substrates with a release layer and fired to be ceramic films, followed by transferring onto plastic substrates using adhesives. The ceramic films thus fabricated on plastics exhibit a certain degree of flexibility, implying the possibility of the technique to be applied to high-throughput roll-to-roll processes. Using this technique, we successfully realized transparent anatase thin films that provide high optical reflectance and transparent indium tin oxide thin films that exhibit electrical conductivity on polycarbonate and acrylic resin substrates, respectively. Crystallographically oriented zinc oxide films and patterned zinc oxide films are also demonstrated to be realized on acrylic resin substrates.

  15. Final Technical Report - Advanced Optical Sensors to Minimize Energy Consumption in Polymer Extrusion Processes

    SciTech Connect

    Susan J. Foulk

    2012-07-24

    Project Objective: The objectives of this study are to develop an accurate and stable on-line sensor system to monitor color and composition on-line in polymer melts, to develop a scheme for using the output to control extruders to eliminate the energy, material and operational costs of off-specification product, and to combine or eliminate some extrusion processes. Background: Polymer extrusion processes are difficult to control because the quality achieved in the final product is complexly affected by the properties of the extruder screw, speed of extrusion, temperature, polymer composition, strength and dispersion properties of additives, and feeder system properties. Extruder systems are engineered to be highly reproducible so that when the correct settings to produce a particular product are found, that product can be reliably produced time after time. However market conditions often require changes in the final product, different products or grades may be processed in the same equipment, and feed materials vary from lot to lot. All of these changes require empirical adjustment of extruder settings to produce a product meeting specifications. Optical sensor systems that can continuously monitor the composition and color of the extruded polymer could detect process upsets, drift, blending oscillations, and changes in dispersion of additives. Development of an effective control algorithm using the output of the monitor would enable rapid corrections for changes in materials and operating conditions, thereby eliminating most of the scrap and recycle of current processing. This information could be used to identify extruder systems issues, diagnose problem sources, and suggest corrective actions in real-time to help keep extruder system settings within the optimum control region. Using these advanced optical sensor systems would give extruder operators real-time feedback from their process. They could reduce the amount of off-spec product produced and

  16. Well-ordered polymer nano-fibers with self-cleaning property by disturbing crystallization process.

    PubMed

    Yang, Qin; Luo, Zhuangzhu; Tan, Sheng; Luo, Yimin; Wang, Yunjiao; Zhang, Zhaozhu; Liu, Weimin

    2014-01-01

    Bionic self-cleaning surfaces with well-ordered polymer nano-fibers are firstly fabricated by disturbing crystallization during one-step coating-curing process. Orderly thin (100 nm) and long (5-10 μm) polymer nano-fibers with a certain direction are fabricated by external macroscopic force (F blow) interference introduced by H2 gas flow, leading to superior superhydrophobicity with a water contact angle (WCA) of 170° and a water sliding angle (WSA) of 0-1°. In contrast, nano-wires and nano-bridges (1-8 μm in length/10-80 nm in width) are generated by "spinning/stretching" under internal microscopic force (F T) interference due to significant temperature difference in the non-uniform cooling medium. The findings provide a novel theoretical basis for controllable polymer "bionic lotus" surface and will further promote practical application in many engineering fields such as drag-reduction and anti-icing.

  17. Well-ordered polymer nano-fibers with self-cleaning property by disturbing crystallization process

    NASA Astrophysics Data System (ADS)

    Yang, Qin; Luo, Zhuangzhu; Tan, Sheng; Luo, Yimin; Wang, Yunjiao; Zhang, Zhaozhu; Liu, Weimin

    2014-07-01

    Bionic self-cleaning surfaces with well-ordered polymer nano-fibers are firstly fabricated by disturbing crystallization during one-step coating-curing process. Orderly thin (100 nm) and long (5-10 μm) polymer nano-fibers with a certain direction are fabricated by external macroscopic force ( F blow) interference introduced by H2 gas flow, leading to superior superhydrophobicity with a water contact angle (WCA) of 170° and a water sliding angle (WSA) of 0-1°. In contrast, nano-wires and nano-bridges (1-8 μm in length/10-80 nm in width) are generated by "spinning/stretching" under internal microscopic force ( F T) interference due to significant temperature difference in the non-uniform cooling medium. The findings provide a novel theoretical basis for controllable polymer "bionic lotus" surface and will further promote practical application in many engineering fields such as drag-reduction and anti-icing.

  18. Processing and Material Characterization of Continuous Basalt Fiber Reinforced Ceramic Matrix Composites Using Polymer Derived Ceramics.

    NASA Technical Reports Server (NTRS)

    Cox, Sarah B.

    2014-01-01

    The need for high performance vehicles in the aerospace industry requires materials which can withstand high loads and high temperatures. New developments in launch pads and infrastructure must also be made to handle this intense environment with lightweight, reusable, structural materials. By using more functional materials, better performance can be seen in the launch environment, and launch vehicle designs which have not been previously used can be considered. The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Polymer matrix composites can be used for temperatures up to 260C. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in the composites. In this study, continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. The oxyacetylene torch testing and three point bend testing have been performed on test panels and the test results are presented.

  19. Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

    NASA Technical Reports Server (NTRS)

    Cox, Sarah; Lui, Donovan; Gou, Jihua

    2014-01-01

    The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed, to be cured, and be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000degC. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200degC, -SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Testing for this included thermal and mechanical testing per ASTM standard tests.

  20. Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

    NASA Technical Reports Server (NTRS)

    Cox, Sarah B.; Lui, Donovan; Wang, Xin; Gou, Jihua

    2014-01-01

    The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000 deg C. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200 deg C, Beta-SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Thermal and mechanical testing includes oxyacetylene torch testing and three point bend testing.

  1. Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

    NASA Technical Reports Server (NTRS)

    Cox, Sarah B.; Lui, Donovan; Gou, Jihua

    2014-01-01

    The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000C. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200C, beta-SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Thermal and mechanical testing includes oxyacetylene torch testing and three point bend testing.

  2. Lead zirconate titanate fiber/polymer composites prepared by a replication process

    SciTech Connect

    Waller, D.J.; Safari, A. ); Card, R.J.; O'Toole, M.P. )

    1990-11-01

    The woven replication process was used to fabricate lead zirconate titanate (PZT)/polymer composites with 1-3, 2-3, and 3-3 connectivities by starting with novoloid-derived carbon fiber, woven fabric, and nonwoven felt templates, respectively. Activated carbon-fiber template material was impregnated with PZT by soaking it in a solution containing stoichiometric amounts of dissolved lead, zirconium, titanium, and niobium ions. Heat treatment burned out the carbon, leaving a PZT replica with the same form as the template material. Replicas were sintered in a controlled atmosphere and back-filled with an epoxy polymer to form final composites. This method, which is believed to be adaptable for mass production, is capable of producing composites and extremely fine microstructures. Woven composite samples have fiber tow diameters of 200 to 250 {mu}m and spacings between tows of about 150 to 250 {mu}m. Average d{sub 33} = 90 pC/N, g{sub 33} = 211 mV {center dot} m/N, and d{sub h}g{sub h} hydrophone figure of merit of 2100 {times} 10{sup {minus}15} m{sup 2}/N values are reported for woven PZT/polymer composites.

  3. Processing fragile matter: effect of polymer graft modification on the mechanical properties and processibility of (nano-) particulate solids.

    PubMed

    Schmitt, Michael; Choi, Jihoon; Hui, Chin Min; Chen, Beibei; Korkmaz, Emrullah; Yan, Jiajun; Margel, Shlomo; Ozdoganlar, O Burak; Matyjaszewski, Krzysztof; Bockstaller, Michael R

    2016-04-21

    The effect of polymer modification on the deformation characteristics and processibility of particle assembly structures is analyzed as a function of particle size and degree of polymerization of surface-tethered chains. A pronounced increase of the fracture toughness (by approximately one order of magnitude) is observed as the degree of polymerization exceeds a threshold value that increases with particle size. The threshold value is interpreted as being related to the transition of tethered chains from stretched-to-relaxed conformation (and the associated entanglement of tethered chains) and agrees with predictions from scaling theory. The increase in toughness is reduced with increasing particle size - this effect is rationalized as a consequence of the decrease of entanglement density with increasing dimension of interstitial (void) space in particle array structures. The increased fracture toughness of particle brush materials (with sufficient degree of polymerization of tethered chains) enables the fabrication of ordered colloidal films and even complex 3D shapes by scalable polymer processing techniques, such as spin coating and micromolding. The results, therefore, suggest new opportunities for the processing of colloidal material systems that could find application in the economical fabrication of functional components or systems compromised of colloidal materials.

  4. Processing fragile matter: effect of polymer graft modification on the mechanical properties and processibility of (nano-) particulate solids.

    PubMed

    Schmitt, Michael; Choi, Jihoon; Hui, Chin Min; Chen, Beibei; Korkmaz, Emrullah; Yan, Jiajun; Margel, Shlomo; Ozdoganlar, O Burak; Matyjaszewski, Krzysztof; Bockstaller, Michael R

    2016-04-21

    The effect of polymer modification on the deformation characteristics and processibility of particle assembly structures is analyzed as a function of particle size and degree of polymerization of surface-tethered chains. A pronounced increase of the fracture toughness (by approximately one order of magnitude) is observed as the degree of polymerization exceeds a threshold value that increases with particle size. The threshold value is interpreted as being related to the transition of tethered chains from stretched-to-relaxed conformation (and the associated entanglement of tethered chains) and agrees with predictions from scaling theory. The increase in toughness is reduced with increasing particle size - this effect is rationalized as a consequence of the decrease of entanglement density with increasing dimension of interstitial (void) space in particle array structures. The increased fracture toughness of particle brush materials (with sufficient degree of polymerization of tethered chains) enables the fabrication of ordered colloidal films and even complex 3D shapes by scalable polymer processing techniques, such as spin coating and micromolding. The results, therefore, suggest new opportunities for the processing of colloidal material systems that could find application in the economical fabrication of functional components or systems compromised of colloidal materials. PMID:26979521

  5. A stable solution-processed polymer semiconductor with record high-mobility for printed transistors

    PubMed Central

    Li, Jun; Zhao, Yan; Tan, Huei Shuan; Guo, Yunlong; Di, Chong-An; Yu, Gui; Liu, Yunqi; Lin, Ming; Lim, Suo Hon; Zhou, Yuhua; Su, Haibin; Ong, Beng S.

    2012-01-01

    Microelectronic circuits/arrays produced via high-speed printing instead of traditional photolithographic processes offer an appealing approach to creating the long-sought after, low-cost, large-area flexible electronics. Foremost among critical enablers to propel this paradigm shift in manufacturing is a stable, solution-processable, high-performance semiconductor for printing functionally capable thin-film transistors — fundamental building blocks of microelectronics. We report herein the processing and optimisation of solution-processable polymer semiconductors for thin-film transistors, demonstrating very high field-effect mobility, high on/off ratio, and excellent shelf-life and operating stabilities under ambient conditions. Exceptionally high-gain inverters and functional ring oscillator devices on flexible substrates have been demonstrated. This optimised polymer semiconductor represents a significant progress in semiconductor development, dispelling prevalent skepticism surrounding practical usability of organic semiconductors for high-performance microelectronic devices, opening up application opportunities hitherto functionally or economically inaccessible with silicon technologies, and providing an excellent structural framework for fundamental studies of charge transport in organic systems. PMID:23082244

  6. Micro-processing of polymers and biological materials using high repetition rate femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Ding, Li

    High repetition rate femtosecond laser micro-processing has been applied to ophthalmological hydrogel polymers and ocular tissues to create novel refractive and diffractive structures. Through the optimization of laser irradiation conditions and material properties, this technology has become feasible for future industrial applications and clinical practices. A femtosecond laser micro-processing workstation has been designed and developed. Different experimental parameters of the workstation such as laser pulse duration, focusing lens, and translational stages have been described and discussed. Diffractive gratings and three-dimensional waveguides have been fabricated and characterized in hydrogel polymers, and refractive index modifications as large as + 0.06 have been observed within the laser-irradiated region. Raman spectroscopic studies have shown that our femtosecond laser micro-processing induces significant thermal accumulation, resulting in a densification of the polymer network and increasing the localized refractive index of polymers within the laser irradiated region. Different kinds of dye chromophores have been doped in hydrogel polymers to enhance the two-photon absorption during femtosecond laser micro-processing. As the result, laser scanning speed can be greatly increased while the large refractive index modifications remain. Femtosecond laser wavelength and pulse energy as well as water and dye concentration of the hydrogels are optimized. Lightly fixed ocular tissues such as corneas and lenses have been micro-processed by focused femtosecond laser pulses, and refractive index modifications without any tissue-breakdown are observed within the stromal layer of the corneas and the cortex of the lenses. Living corneas are doped with Sodium Fluorescein to increase the two-photon absorption during the laser micro-processing, and laser scanning speed can be greatly increased while inducing large refractive index modifications. No evidence of cell death

  7. Novel configuration of poly(vinylidenedifluoride)-based gel polymer electrolyte for application in lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Fasciani, Chiara; Panero, Stefania; Hassoun, Jusef; Scrosati, Bruno

    2015-10-01

    Herein we propose a novel poly(vinylidene difluoride) (PVdF)-based gel polymer electrolyte (GPE) for application in lithium-ion batteries, LIBs. The GPE is prepared under air as a dry, flexible film and directly gelled during LIB assembly with a conventional liquid organic electrolyte. The dry-gel here originally reported maintains its structural integrity due to the presence of crystallized EC-solvent within its matrix that avoids structural collapse, as demonstrated by TGA analysis. By avoiding the use of controlled atmosphere, the GPE is easy to handle and suitable for roll-to-roll scaling-up, i.e. characteristics missed by the common gel membranes. Scanning Electron Microscopy (SEM) evidences a micrometric polymer network of the dry membrane precursor acting as the support matrix for the gelation. Electrochemical impedance spectroscopy (EIS) measurements and galvanostatic tests suggest a good stability of the lithium electrode/gel electrolyte interface and a satisfactory lithium transference number. Cycling tests of gel-electrolyte-based lithium half-cells using lithium iron phosphate (LiFePO4, LFP) and graphite (C), respectively, as counter electrodes, as well as of a full C/LFP lithium-ion battery confirm the suitability of the GPE developed in this work for application in stable, low cost and environmentally friendly energy storage systems.

  8. Manufacture of porous polymer nerve conduits through a lyophilizing and wire-heating process.

    PubMed

    Huang, Yi-Cheng; Huang, Yi-You; Huang, Chun-Chieh; Liu, Hwa-Chang

    2005-07-01

    We have developed a method for nerve tissue regeneration using longitudinally oriented channels within biodegradable polymers created by a combined lyophilizing and wire-heating process. This type of cell-adhesive scaffold provides increased area to support and guide extending axons subsequent to nerve injury. Utilizing Ni-Cr wires as mandrels to create channels in scaffold increased safety, effectiveness, and reproducibility. The scaffolds tested were made from different biodegradable polymers, chitosan and poly(D,L-lactide-co-glycolide) (PLGA), because of their availability, ease of processing, low inflammatory response, and approval by the FDA. According to our experimental results, the high permeability and the characteristic porous structure of chitosan proved to be a better material for nerve guidance than PLGA. The scanning electron micrographs revealed that the scaffolds were consistent along the longitudinal axis with channels being distributed evenly throughout the scaffolds. There was no evidence to suggest merging or splitting of individual channels. The diameter of the channels was about 100 mum, similar to the 115 micromameter of the Ni-Cr wire. Regulating the size and quantity of the Ni-Cr wires allow us to control the number and the diameter of the channels. Furthermore, the neutralizing processes significantly influenced the porous structure of chitosan scaffolds. Using weak base (NaHCO(3) 1M) to neutralize chitosan scaffolds made the porous structure more uniform. The innovative method of using Ni-Cr wires as mandrels could be easily tailored to other polymer and solvent systems. The high permeability and the characteristic porous structure of chitosan made it a superior material for nerve tissue engineering. These scaffolds could be useful for guiding regeneration of the peripheral nerve or spinal cord after a transection injury. PMID:15909301

  9. Particle beam experiments for the analysis of reactive sputtering processes in metals and polymer surfaces

    SciTech Connect

    Corbella, Carles; Grosse-Kreul, Simon; Kreiter, Oliver; Arcos, Teresa de los; Benedikt, Jan; Keudell, Achim von

    2013-10-15

    A beam experiment is presented to study heterogeneous reactions relevant to plasma-surface interactions in reactive sputtering applications. Atom and ion sources are focused onto the sample to expose it to quantified beams of oxygen, nitrogen, hydrogen, noble gas ions, and metal vapor. The heterogeneous surface processes are monitored in situ by means of a quartz crystal microbalance and Fourier transform infrared spectroscopy. Two examples illustrate the capabilities of the particle beam setup: oxidation and nitriding of aluminum as a model of target poisoning during reactive magnetron sputtering, and plasma pre-treatment of polymers (PET, PP)

  10. Particle beam experiments for the analysis of reactive sputtering processes in metals and polymer surfaces

    NASA Astrophysics Data System (ADS)

    Corbella, Carles; Grosse-Kreul, Simon; Kreiter, Oliver; de los Arcos, Teresa; Benedikt, Jan; von Keudell, Achim

    2013-10-01

    A beam experiment is presented to study heterogeneous reactions relevant to plasma-surface interactions in reactive sputtering applications. Atom and ion sources are focused onto the sample to expose it to quantified beams of oxygen, nitrogen, hydrogen, noble gas ions, and metal vapor. The heterogeneous surface processes are monitored in situ by means of a quartz crystal microbalance and Fourier transform infrared spectroscopy. Two examples illustrate the capabilities of the particle beam setup: oxidation and nitriding of aluminum as a model of target poisoning during reactive magnetron sputtering, and plasma pre-treatment of polymers (PET, PP).

  11. Remineralization of Artificial Dentin Lesions via the Polymer-Induced Liquid-Precursor (PILP) Process.

    PubMed

    Thula-Mata, Taili; Burwell, Anora; Gower, Laurie B; Habeliz, Stefan; Marshall, Grayson W

    2011-01-01

    Acid-etched dentin samples with a zone of demineralized dentin were remineralized via the polymer-induced liquid-precursor (PILP) process. Poly-L-aspartic acid was used as the polymeric process-directing agent. Samples were incubated in the mineralization solution for 1-4 weeks. Dentin samples remineralized by the PILP process presented a surface morphology very similar to the intact mineralized dentin's architecture, in contrast to samples mineralized via the conventional nucleation and growth method (without polymer additive), which led to a superficial crust of randomly organized mineral crystals. Energy dispersive x-ray spectroscopy analysis of the PILP-mineralized samples showed the presence of calcium and phosphate ions at high levels. Since no hydroxyapatite (HA) clusters were observed on the surface of the PILP-mineralized samples, we could conclude the signal was produced from the mineral embedded within the dentin matrix. TEM and diffraction analyses suggest that both intrafibrillar and interfibrillar remineralization occurred in the demineralized dentin matrix.

  12. Remineralization of Artificial Dentin Lesions via the Polymer-Induced Liquid-Precursor (PILP) Process

    PubMed Central

    Thula-Mata, Taili; Burwell, Anora; Gower, Laurie B.; Habeliz, Stefan; Marshall, Grayson W.

    2011-01-01

    Acid-etched dentin samples with a zone of demineralized dentin were remineralized via the polymer-induced liquid-precursor (PILP) process. Poly-L-aspartic acid was used as the polymeric process-directing agent. Samples were incubated in the mineralization solution for 1–4 weeks. Dentin samples remineralized by the PILP process presented a surface morphology very similar to the intact mineralized dentin’s architecture, in contrast to samples mineralized via the conventional nucleation and growth method (without polymer additive), which led to a superficial crust of randomly organized mineral crystals. Energy dispersive x-ray spectroscopy analysis of the PILP-mineralized samples showed the presence of calcium and phosphate ions at high levels. Since no hydroxyapatite (HA) clusters were observed on the surface of the PILP-mineralized samples, we could conclude the signal was produced from the mineral embedded within the dentin matrix. TEM and diffraction analyses suggest that both intrafibrillar and interfibrillar remineralization occurred in the demineralized dentin matrix. PMID:24839340

  13. Microstructure Changes of Copper Nano Particles via Polymer Solution and Reduction Firing Processes.

    PubMed

    Han, Young-Min; Jung, Choong-Hwan; Lee, Sang-Jin

    2016-02-01

    Cu nano particles were fabricated at a very low temperature via polymer solution and reduction firing processes using a polyvinyl alcohol (PVA) and Ar-4%H2 gas mixture. In the process, copper nitrate and 5 wt% PVA solution were dissolved in D.I. water and the organic-inorganic precursor sols were dried to porous gels. The precursor gels were calcined in an air atmosphere, and then refired at 250 degrees C-300 degrees C under an Ar-4%H2 atmosphere for the reduction of CuO. The morphology of precursor gels and CuO and Cu powders was strongly dependent on the PVA content, and the as- calcined CuO readily deoxidized to Cu with minimal residual carbon. The polymer also contributed to an atomic-scale copper cation distribution, which resulted in nano-sized CuO and Cu powders. The Cu powder synthesized with PVA content in a 4:1 ratio showed a crystallite size of about 20 nm or less. In this paper, the microstructure changes of Cu nano particles at each set of processing conditions were examined by SEM and TEM observations.

  14. High-energy radiation and polymers: A review of commercial processes and emerging applications

    NASA Astrophysics Data System (ADS)

    Clough, R. L.

    2001-12-01

    Ionizing radiation has been found to be widely applicable in modifying the structure and properties of polymers, and can be used to tailor the performance of either bulk materials or surfaces. Fifty years of research in polymer radiation chemistry has led to numerous applications of commercial and economic importance, and work remains active in the application of radiation to practical uses involving polymeric materials. This paper provides a survey of radiation-processing methods of industrial interest, ranging from technologies already commercially well established, through innovations in the active R&D stage which show exceptional promise for future commercial use. Radiation-processing technologies are discussed under the following categories: cross-linking of plastics and rubbers, curing of coatings and inks, heat-shrink products, fiber-matrix composites, chain-scission for processing control, surface modification, grafting, hydrogels, sterilization, natural product enhancement, plastics recycling, ceramic precursors, electronic property materials, ion-track membranes and lithography for microdevice production. In addition to new technological innovations utilizing conventional gamma and e-beam sources, a number of promising new applications make use of novel radiation types which include ion beams (heavy ions, light ions, highly focused microscopic beams and high-intensity pulses), soft X-rays which are focused, coherent X-rays (from a synchrotron) and e-beams which undergo scattering to generate patterns.

  15. High-performance polymers from nature: catalytic routes and processes for industry.

    PubMed

    Walther, Guido

    2014-08-01

    It is difficult to imagine life today without polymers. However, most chemicals are almost exclusively synthesized from petroleum. With diminishing oil reserves, establishing an industrial process to transform renewables into high-value chemicals may be more challenging than running a car without gasoline. This is due to the difficulty in setting up processes that are novel, profitable, and environmentally benign at the same time. Additionally, the quest for sustainability of renewable resources should be based on incorporating ethical considerations in the development of plans that utilize feedstocks intended for human nutrition and health. Thus, it is important to use bio-energy containing renewable resources in the most efficient way. This Concept goes beyond the synthesis of monomers and provides insights for establishing an industrial process that transforms renewable resources into high-value chemicals, and it describes careful investigations that are of paramount importance, including evaluations from an economical and an ecological perspective. The synthesis of monomers suitable for polymer production from renewable resources would ideally be accompanied by a reduction in CO2 emission and waste, through the complete molecular utilization of the feedstock. This Concept advocates the drop-in strategy, and is guided by the example of catalytically synthesized dimethyl 1,19-nonadecanedioate and its α,ω-functionalized derivatives. With respect to the Twelve Principles of Green Chemistry, this Concept describes a technological leap forward for a sustainable green chemical industry. PMID:25049162

  16. High-performance polymers from nature: catalytic routes and processes for industry.

    PubMed

    Walther, Guido

    2014-08-01

    It is difficult to imagine life today without polymers. However, most chemicals are almost exclusively synthesized from petroleum. With diminishing oil reserves, establishing an industrial process to transform renewables into high-value chemicals may be more challenging than running a car without gasoline. This is due to the difficulty in setting up processes that are novel, profitable, and environmentally benign at the same time. Additionally, the quest for sustainability of renewable resources should be based on incorporating ethical considerations in the development of plans that utilize feedstocks intended for human nutrition and health. Thus, it is important to use bio-energy containing renewable resources in the most efficient way. This Concept goes beyond the synthesis of monomers and provides insights for establishing an industrial process that transforms renewable resources into high-value chemicals, and it describes careful investigations that are of paramount importance, including evaluations from an economical and an ecological perspective. The synthesis of monomers suitable for polymer production from renewable resources would ideally be accompanied by a reduction in CO2 emission and waste, through the complete molecular utilization of the feedstock. This Concept advocates the drop-in strategy, and is guided by the example of catalytically synthesized dimethyl 1,19-nonadecanedioate and its α,ω-functionalized derivatives. With respect to the Twelve Principles of Green Chemistry, this Concept describes a technological leap forward for a sustainable green chemical industry.

  17. Coarse-grained molecular dynamics simulation of the void growth process in the block structure of semicrystalline polymers

    NASA Astrophysics Data System (ADS)

    Higuchi, Yuji; Kubo, Momoji

    2016-06-01

    We study fracture processes of amorphous and semicrystalline polymers with a coarse-grained molecular dynamics simulation. In the amorphous state, the stress caused by strain mainly arises from the loss of the attractive interaction in the voids. However, in semicrystalline polymers, the elongation of bonding is the dominant factor and it causes much more stress than that in an amorphous state. This is because growth of the voids is prevented by the amorphous regions and it is difficult to relax the folded polymers.

  18. Active barrier films of PET for solar cell application: Processing and characterization

    SciTech Connect

    Rossi, Gabriella; Scarfato, Paola; Incarnato, Loredana

    2014-05-15

    A preliminary investigation was carried out on the possibility to improve the protective action offered by the standard multilayer structures used to encapsulate photovoltaic devices. With this aim, a commercial active barrier PET-based material, able to absorb oxygen when activated by liquid water, was used to produce flexible and transparent active barrier films, by means of a lab-scale film production plant. The obtained film, tested in terms of thermal, optical and oxygen absorption properties, shows a slow oxygen absorption kinetics, an acceptable transparency and an easy roll-to-roll processability, so proving itself as a good candidate for the development of protective coating for solar cells against the atmospheric degradation agents like the rain.

  19. A solution processed top emission OLED with transparent carbon nanotube electrodes

    NASA Astrophysics Data System (ADS)

    Chien, Yu-Mo; Lefevre, Florent; Shih, Ishiang; Izquierdo, Ricardo

    2010-04-01

    Top emission organic light emitting diodes (OLEDs) with carbon nanotubes (CNTs) as top electrodes were fabricated and characterized. Devices were fabricated on glass substrates with evaporated bottom Al/LiF cathodes, a spin coated organic emissive layer and a PEDOT-PSS hole injection layer. Transparent thin CNT films were deposited on top of the emission layer to form the anode by micro-contact printing with a polydimethylsiloxane stamp. A very good device performance was obtained, with a peak luminance of 3588 cd m - 2 and a maximum current efficiency of 1.24 cd A - 1. This work shows the possibility of using CNTs as transparent electrodes to replace ITO in organic semiconductor devices. Furthermore, the top emission nature of such devices offers a broader range of applications of CNTs on any type of substrate. By combining with solution processed organic materials, it is anticipated that lower cost fabrication will be possible through roll-to-roll manufacture.

  20. Deposition of calcium carbonate films by a polymer-induced liquid-precursor (PILP) process

    NASA Astrophysics Data System (ADS)

    Gower, Laurie B.; Odom, Damian J.

    2000-03-01

    A polypeptide additive has been used to transform the solution crystallization of calcium carbonate to a solidification process of a liquid-phase mineral precursor. In situ observations reveal that polyaspartate induces liquid-liquid phase separation of droplets of a mineral precursor. The droplets deposit on the substrate and coalesce to form a coating, which then solidifies into calcitic tablets and films. Transition bars form during the amorphous to crystalline transition, leading to sectorization of calcite tablets, and the defect textures and crystal morphologies are atypical of solution grown crystals. The formation of nonequilibrium crystal morphologies using an acidic polypeptide may have implications in the field of biomineralization, and the environmentally friendly aspects of this polymer-induced liquid-precursor (PILP) process may offer new techniques for aqueous-based processing of ceramic films, coatings, and particulates.

  1. Hollow polymer microneedle array fabricated by photolithography process combined with micromolding technique.

    PubMed

    Wang, Po-Chun; Wester, Brock A; Rajaraman, Swaminathan; Paik, Seung-Joon; Kim, Seong-Hyok; Allen, Mark G

    2009-01-01

    Transdermal drug delivery through microneedles is a minimally invasive procedure causing little or no pain, and is a potentially attractive alternative to intramuscular and subdermal drug delivery methods. This paper demonstrates the fabrication of a hollow microneedle array using a polymer-based process combining UV photolithography and replica molding techniques. The key characteristic of the proposed fabrication process is to define a hollow lumen for microfluidic access via photopatterning, allowing a batch process as well as high throughput. A hollow SU-8 microneedle array, consisting of 825mum tall and 400 mum wide microneedles with 15-25 mum tip diameters and 120 mum diameter hollow lumens was designed, fabricated and characterized. PMID:19964192

  2. Study of mould design and forming process on advanced polymer-matrix composite complex structure

    NASA Astrophysics Data System (ADS)

    Li, S. J.; Zhan, L. H.; Bai, H. M.; Chen, X. P.; Zhou, Y. Q.

    2015-07-01

    Advanced carbon fibre-reinforced polymer-matrix composites are widely applied to aviation manufacturing field due to their outstanding performance. In this paper, the mould design and forming process of the complex composite structure were discussed in detail using the hat stiffened structure as an example. The key issues of the moulddesign were analyzed, and the corresponding solutions were also presented. The crucial control points of the forming process such as the determination of materials and stacking sequence, the temperature and pressure route of the co-curing process were introduced. In order to guarantee the forming quality of the composite hat stiffened structure, a mathematical model about the aperture of rubber mandrel was introduced. The study presented in this paper may provide some actual references for the design and manufacture of the important complex composite structures.

  3. Improving processing and toughness of a high performance composite matrix through an interpenetrating polymer network. VI

    NASA Technical Reports Server (NTRS)

    Pater, Ruth H.

    1990-01-01

    A simultaneous semi-interpenetrating polymer network (semi-IPN) concept is presented which combines easy-to-process, but brittle, thermosetting polyimides with tough, but difficult to process, linear thermoplastic polyimides. The combination results in a semi-IPN with the easy processability of a thermoset and good toughness of a thermoplastic. Four simultaneous semi-IPN systems were developed from commercially available NR-150B2 combined with each of the four Thermid materials (LR-600, AL-600, MC-600, and FA-700). It is concluded that there is a significant improvement in resin fracture toughness of Thermid-polyimide-based semi-IPN systems and some improvement in composite microcracking resistance compared to Thermid LR-600. Excellent composite mechanical properties have been achieved. These new semi-IPN materials have the potential to be used as composite matrices, adhesives, and molding materials.

  4. In-process, non-destructive, dynamic testing of high-speed polymer composite rotors

    NASA Astrophysics Data System (ADS)

    Kuschmierz, Robert; Filippatos, Angelos; Günther, Philipp; Langkamp, Albert; Hufenbach, Werner; Czarske, Jürgen; Fischer, Andreas

    2015-03-01

    Polymer composite rotors are lightweight and offer great perspectives in high-speed applications such as turbo machinery. Currently, novel rotor structures and materials are investigated for the purpose of increasing machine efficiency and lifetime, as well as allowing for higher dynamic loads. However, due to the complexity of the composite materials an in-process measurement system is required. This allows for monitoring the evolution of damages under dynamic loads, for testing and predicting the structural integrity of composite rotors in process. In rotor design, it can be used for calibrating and improving models, simulating the dynamic behaviour of polymer composite rotors. The measurement system is to work non-invasive, offer micron uncertainty, as well as a high measurement rate of several tens of kHz. Furthermore, it must be applicable at high surface speeds and under technical vacuum. In order to fulfil these demands a novel laser distance measurement system was developed. It provides the angle resolved measurement of the biaxial deformation of a fibre-reinforced polymer composite rotor with micron uncertainty at surface speeds of more than 300 m/s. Furthermore, a simulation procedure combining a finite element model and a damage mechanics model is applied. A comparison of the measured data and the numerically calculated data is performed to validate the simulation towards rotor expansion. This validating procedure can be used for a model calibration in the future. The simulation procedure could be used to investigate different damage-test cases of the rotor, in order to define its structural behaviour without further experiments.

  5. High performance hyperbranched polymers for improved processing and mechanical properties in thermoset composites

    NASA Astrophysics Data System (ADS)

    Marsh, Timothy

    Hyperbranched polymers, specifically hyperbranched poly(arylene ether ketone imide)s (HBPAEKI), are here studied as blend additives in thermoset composites to improve processing and ultimate performance properties of the composite. Monomer synthesis for HBPAEKI was further advanced in this work leading to higher yields, fewer reactions, and shorter production times. A five step synthetic method with an overall yield of 12% was reduced to a three step process with an overall yield of 38%. Polymer was synthesized under varying conditions and end group chemistry for use in thermoset blends. NMR characterization allowed for the assignment of chemical shifts in monomer and cataloguing of shifts in polymer for use in future work to characterize degree of branching. Cure kinetics of blends of HBPAEKI are explored through the use of differential scanning calorimetry (DSC) and chemorheology using small angle oscillatory shear. In a phenylethynyl terminated imide oligomer (PETI) thermoset resin, reactive phenylethynyl endcapped PAEKI (PEPAEKI) was found to retard cure while non reactive alkyl endcapped PAEKI was found to accelerate cure in DGEBA/DAH epoxy systems. Minimal effect was seen on early stage blend viscosity. Composite properties tested focused on the effect on bulk fracture and interfacial shear strength. No significant effect was seen in fracture toughness by SENB. XPS was used to verify that PEPAEKI was surface active to DGEBA/DDS epoxy/air interfaces to the complete exclusion of the epoxy at the surface. Evidence was also seen consistent with surface activity in alkyl endcapped PAEKI in DGEBA/DAH systems, although the contrast is much lower. Effect of alkyl endcapped HBPAEKI on interfacial shear strength was examined through the use of t-peel and single fiber fracture (SFF) techniques. In some systems, t-peel indicates a clear improvement in peel force, proportional to the blend concentration. In SFF, interfacial shear strength was found to be equal or slightly

  6. Photoaddressable Polymers

    NASA Astrophysics Data System (ADS)

    Bieringer, T.

    Polymers are the perfect materials for a variety of applications in almost every field of technical as well as human life. Because of their macromolecular architecture there are a lot of degrees of freedom in the synthesis of polymers. Owing to the change of their functional composition, they can be tailored even for quite difficult demands. Since a whole industry deals with the processing of polymers, cheap production lines have been developed for almost every polymer. This is the reason why not only the molecular composition but even the price of polymers has been optimized. Therefore these materials can be considered as encouraging components even in highly sophisticated areas of applications.

  7. Development and characterization of polymers-metallic hot embossing process for manufacturing metallic micro-parts

    NASA Astrophysics Data System (ADS)

    Sahli, M.; Millot, C.; Gelin, J.-C.; Barrière, T.

    2011-01-01

    In the recent years, hot embossing process becomes a promising process for the replication of polymer micro-structures associated to its manufacturing capability related to a relatively low component cost. This rising demand has prompted the development of various micro-manufacturing techniques in an attempt to get micro-parts in large batch. The paper investigates the way to get metallic micro-parts through the hot embossing process. The micro-manufacturing process consists in three stages. In the first one, the different metallic feedstocks with 50 to 60% powder loading in volume have been prepared with adapted polymers/powders formulations. In a second stage, an elastomeric master has been used to obtain micro-parts on a plastic loaded substrate with developed mixture based on polypropylene, paraffin wax and stearic acid. Finally, a thermal debinding stage in nitrogen atmosphere followed by a solid state pre-sintering stage has been applied, in order to eliminate the pores between powder particles in the debinded components. Then the porous components are agglomerated by solid state diffusion after heating to a temperature slightly lower than the melting temperature related to the material used in the process, to form an homogenous structure when full densification is achieved. The advantages of this approach include: rapid manufacturing of injection tools with high-quality, easy demoulding of metallic parts from the elastomeric moulds and great flexibility related to the choices of material. The paper describes all the processing stages and the way to characterize the geometrical, physical and mechanical properties of the resulting micro-parts.

  8. Viscoelastic effects in relaxation processes of concentration fluctuations in dynamically asymmetric polymer blends

    NASA Astrophysics Data System (ADS)

    Takenaka, Mikihito; Takeno, Hiroyuki; Hasegawa, Hirokazu; Saito, Shin; Hashimoto, Takeji; Nagao, Michihiro

    2002-02-01

    Relaxation processes of the concentration fluctuations induced by a rapid pressure change were investigated for a dynamically asymmetric polymer blend [deuterated polybutadiene (DPB)/polyisoprene (PI)] with a composition of 50-50 by weight by using time-resolved small-angle neutron scattering. The pressure change was carried out inside the single-phase of the blend with the cell designed for polymeric systems under high pressure and temperature. Time change in the scattered intensity distribution with wave number (q) during the relaxation processes was found to be approximated by Cahn-Hilliard-Cook linearized theory. The theoretical analysis yielded the q dependence of Onsager kinetic coefficient that is characterized by the q-2 dependence at qξve>1 with the characteristic length ξve (with ξve being the viscoelastic length) being much larger than radius of gyration of DPB or PI. The estimated ξve agrees well with that calculated using the Doi and Onuki theory that takes into account the viscoelastic effects arising from the dynamical asymmetry between the component polymers in the relaxation of concentration fluctuations.

  9. Hybrid polymers processed by substrate conformal imprint lithography for the fabrication of planar Bragg gratings

    NASA Astrophysics Data System (ADS)

    Foerthner, M.; Rumler, M.; Stumpf, F.; Fader, R.; Rommel, M.; Frey, L.; Girschikofsky, M.; Belle, S.; Hellmann, R.; Klein, J. J.

    2016-03-01

    In this work, we present an approach to use UV-enhanced substrate conformal imprint lithography (UV-SCIL) as a soft imprint technique combined with excimer laser irradiation to manufacture Bragg gratings within planar waveguides on a full-wafer scale. For the first time, different hybrid polymers (OrmoComp®, OrmoStamp, OrmoCore, OrmoClad and OrmoClear) could be successfully patterned using UV-SCIL. For OrmoComp® (showing results very similar to OrmoStamp and OrmoClad), a complete imprint process could be realized. OrmoCore formed an inhibition layer in the presence of oxygen during the imprint, as could be observed for the use of OrmoClear as well. Processing options were elaborated to reduce the inhibition effect significantly, whereby the latter is mainly due to the atmospheric oxygen-containing PDMS layer of the UV-SCIL working stamp. Further on, the successful realization of a planar Bragg grating operating at the telecom wavelength is demonstrated by tuning the refractive index (RI) of OrmoComp® using a phase mask and an UV excimer laser. FTIR measurements show that the change in RI can be clearly correlated with a change in the chemical composition of the hybrid polymer during laser exposure.

  10. Processing and quantitative analysis of biodegradable polymers (PLLA and PCL) thermal bonding

    NASA Astrophysics Data System (ADS)

    Boutry, C. M.; Kiran, R.; Umbrecht, F.; Hierold, C.

    2010-08-01

    A quantitative analysis of the bond strength and microstructure integrity achieved when bonding the biodegradable polymers poly(L-lactide) (PLLA) and poly(ɛ-caprolactone) (PCL) has been performed using the response surface methodology. The respective influence of the bonding parameters (temperature, pressure, duration) on the bond strength and microchannel integrity was investigated. PLLA and PCL were identified as suitable candidates for packaging materials for bioelectronic circuits of conductive biodegradable polymers. For a future packaging application, the bonding parameters were adapted to optimize the bond strength; the estimated values for the bond strength and channel integrity that were predicted by the surface plots were 2.32 ± 0.26 MPa and 33.7 ± 12.9% for PLLA, and 0.81 ± 0.11 MPa and 50.9 ± 5.7% for PCL. These values were in good agreement with the experimentally determined bond strength of 2.00 ± 1.10 MPa (PLLA) and 0.67 ± 0.22 MPa (PCL) and deformation of 31.4 ± 7.0% (PLLA) and 52.9 ± 4.1% (PCL). Microchannels with an aspect ratio of 1:12.5 were successfully fabricated. The impact of the fabrication process on the PLLA and PCL chemical properties was also investigated through differential scanning calorimetry and gel permeation chromatography measurements. It was observed that the weight average molecular weight Mw decreases after each fabrication step, as much as 68% for PLLA and 59% for PCL. The strongest reduction was observed after the compression molding (above the melting temperature) which should be kept as short as possible. An annealing step allowed increasing the crystallinity and improved the overall polymer stiffness.

  11. Direct laser-assisted processing of polymers for microfluidic and micro-optical applications

    NASA Astrophysics Data System (ADS)

    Pfleging, Wilhelm; Boehm, Johannes; Finke, Steffi; Gaganidze, E.; Hanemann, Thomas; Heidinger, Roland; Litfin, Karsten

    2003-07-01

    In the microscopic world the need of functional prototypes increases, e.g. as a precondition for a mould insert fabrication for micro-injection moulding. In this work the direct fabrication of prototypes made from polymers with an accuracy down to the micrometer range will be presented. For this purpose the direct patterning or modification of polymers with UV-laser radiation is performed for applications in fluidic and micro-optics. Different UV laser sources such as excimer and frequency-multiplied Nd:YAG were used. In the case of complex designs for fluidic applications it is powerful to use Nd:YAG laser radiation as patterning tool because of their high laser repetition rates: CAD data from complex fluidic designs were transmitted directly via CAM module into the polymeric surface. Because of the very small laser pulse duration of about 400-500 ps the thermal-induced damage during ablation decreases significantly. Process parameters, ablation rates and attainable surface qualities for capillary-electrophoreses chips will be presented. With the aid of a motorised aperture or a rotating mask system, excimer laser radiation is used to enable a well defined patterning of grooves with sharp edges and smooth sidewalls. The direct ablation of polymethylmethacrylate (PMMA), as well as the laser induced modification of the polymeric chemistry is used for the preparation of passive integrated-optical waveguides. Two types of concepts of waveguides are discussed: 1. Laser patterned grooves are filled with index matched materials which leads either to an increase or a decrease of the refractive index relative to pure PMMA. 2. Localised laser-induced polymer modification leads immediately to an integrated waveguide with higher refractive index. Both types of waveguides-concepts are characterised by their optical properties, which will be discussed in detail.

  12. Improving processing and toughness of a high performance composite matrix through an interpenetrating polymer network. VI

    NASA Technical Reports Server (NTRS)

    Pater, Ruth H.

    1990-01-01

    The use of a semiinterpenetrating polymer network (SIPN) of the high-performance polyimide NR-150B2 to reduce brittleness and improve processability in the highly crosslinked acetylene-terminated polyimides Thermid LR-600, AL-600, MC-600, and FA-700 is described. The theoretical basis of the SIPN process is reviewed; the preparation and characterization of the neat SIPN resins and unidirectional graphite-fiber composites are explained; and the results are presented in extensive tables, graphs, and micrographs and discussed in detail. Significant increases in fracture energy were observed with SIPN, from 93 J/sq m for unmodified LR-600 to 283-603 J/sq m for the SIPN materials; the room-temperature flexural strength of the unidirectional composites also increased, from 1344 MPa for an unmodified MC-600 composite to 2020-1751 MPa for the SIPN composites. The potential applicability of SIPN-based composites to aerospace structures and electronic components is indicated.

  13. Controlling the drying and film formation processes of polymer solution droplets with addition of small amount of surfactants.

    PubMed

    Kajiya, Tadashi; Kobayashi, Wataru; Okuzono, Tohru; Doi, Masao

    2009-11-26

    We studied how the addition of surfactants alters the drying and film formation processes of polymer solution droplets with contact lines strongly fixed by bank structures. We found that even if the amount of surfactant is quite small, it drastically changes the final profile of the polymer film from a ringlike profile to a flat profile. This property is observed commonly, irrespective of the polymer concentration, droplet volume, and type of solvent. We conjecture that the inhomogeneous distribution of the surfactant caused by the outward capillary flow induces the Marangoni flow directed toward the center of the droplet, which suppresses the outward flow. The present phenomenon implies an effective method for controlling the profile of the polymer film in inkjet printing technologies.

  14. Polymer light-emitting devices with novel cathode structures and full-color patterning processes

    NASA Astrophysics Data System (ADS)

    Deng, Xianyu

    2006-12-01

    In the past decades, polymeric light-emitting diode (PLED) have been a focus of research interest to scientists all over the world due to its potential application in flat panel displays. In previous studies, tremendous progresses in material developments, device engineering and theoretical modeling for PLEDs have been achieved. However, there are still a number of crucial problems to be solved in order for PLEDs to be widely employed in commercial flat panel displays. In this thesis, we present studies of PLEDs that used a high work-function metal aluminum as the cathode. The device exhibits a highly enhanced efficiency by modifying the cathode using certain non-ionic surfactant polymers. Based on this finding, we further demonstrated top-emitting PLEDs with environmentally stable cathodes. In another development, we show that a three-coloremitting device with a bilayer emitting polymer structure can be achieved by a dry photo-patterning process. Each of the red, green and blue emission in the device has a comparable emitting efficiency to the traditional standard red, green or blue device with single color emission. These results are believed to be important and beneficial for obtaining low-cost, large-scale and long life-time flat panel displays based on PLEDs.

  15. Critical Role of Processing on the Thermoelectric Performance of Doped Semiconducting Polymers

    NASA Astrophysics Data System (ADS)

    Patel, Shrayesh; Glaudell, Anne; Chabinyc, Michael

    The ability to convert excess waste heat into useable energy can significantly help meet the global energy demands. One may capture this waste heat through thermoelectrics devices. In a thermoelectric material, the charge carriers transport both electrical current and heat. Consequently, under a temperature difference (ΔT), a carrier concentration gradient results in a voltage (ΔV), which is related to the Seebeck coefficient, α = - Δ V/ ΔT. One of the challenges lies in finding materials that simultaneously have low thermal conductivity (κ) , high electrical conductivity (σ) , and high Seebeck coefficient (α) . Conjugated semiconducting polymers can potentially meet this demand due to their inherent low thermal conductivity and high electrical conductivity through sufficient doping. Here, we report on the critical role of thermal processing on the enhancement of thermoelectric properties of conjugated polymer thin films. These films were doping using three different mechanisms: acid (toluene sulfonic acid), charge transfer (F4TCNQ), and vapor (fluorinated-alkyl trichlorosilane). These thermoelectrics properties will be correlated to the structural and morphological properties of the doped thin-films through various synchrotron X-ray scattering techniques. Lastly, to further elucidate the charge transport mechanism driving the thermoelectric performance, we report on the temperature-dependent measurements of both the Seebeck coefficient and electrical conductivity.

  16. Ceramic microparticles and capsules via microfluidic processing of a preceramic polymer

    PubMed Central

    Ye, Congwang; Chen, Anthony; Colombo, Paolo; Martinez, Carlos

    2010-01-01

    We have developed a robust technique to fabricate monodispersed solid and porous ceramic particles and capsules from single and double emulsion drops composed of silsesquioxane preceramic polymer. A microcapillary microfluidic device was used to generate the monodispersed drops. In this device, two round capillaries are aligned facing each other inside a square capillary. Three fluids are needed to generate the double emulsions. The inner fluid, which flows through the input capillary, and the middle fluid, which flows through the void space between the square and inner fluid capillaries, form a coaxial co-flow in a direction that is opposite to the flow of the outer fluid. As the three fluids are forced through the exit capillary, the inner and middle fluids break into monodispersed double emulsion drops in a single-step process, at rates of up to 2000 drops s−1. Once the drops are generated, the silsesquioxane is cross-linked in solution and the cross-linked particles are dried and pyrolysed in an inert atmosphere to form oxycarbide glass particles. Particles with diameters ranging from 30 to 180 µm, shell thicknesses ranging from 10 to 50 µm and shell pore diameters ranging from 1 to 10 µm were easily prepared by changing fluid flow rates, device dimensions and fluid composition. The produced particles and capsules can be used in their polymeric state or pyrolysed to ceramic. This technique can be extended to other preceramic polymers and can be used to generate unique core–shell multimaterial particles. PMID:20484226

  17. XIIth international meeting on radiation processing Avignon 25-30 March 2001 (Polymer irradiation: past-present and future)

    NASA Astrophysics Data System (ADS)

    Chapiro, Adolphe

    2002-03-01

    Radiations are used efficiently and economically for the production of new or modified polymers. The following processes are considered: Radiation curing; Radiation cross-linking; Radiation grafting. These processes are commonly used today in industry and provide a broad range of new potential applications in various fields. The history of their development is briefly reported. The chemical reactions underlying these processes are described. (1) Radiation curing is used commercially on a large scale for the production of improved coatings, lacquers and inks. The process can be conducted at very high speeds. Curing of magnetic formulations leads to particularly stable products, which compete favourably with more conventional materials. (2) Radiation cross-linking is an established technology in the wire and cable industry. It emparts to the modified insulators improved resistance to solvents, to ageing and to elevated temperatures. The resulting cross-linked network also reduces the migration of fillers and thereby stabilizes in time any message imprinted with magnetic or colored pigments dispersed in a polymer. (3) Radiation grafting is a powerful method for modifying more profoundly the properties of a polymer and for creating numerous, entirely new materials. The chemical modification can be applied at will into the bulk of the material or limited to a surface zone of any desired depth. This method can be used for instance, for introducing polar groups in the bulk or on the surface of non-polar polymers, for increasing or reducing the wettability of a polymer, for imparting a better compatibility of a polymer to a specific coating and the like. The irradiation of water-soluble polymers in aqueous solutions, with or without the addition of another monomer gives rise to a variety of cross-linked gels which find useful applications in the biomedical field. Other promising applications will be considered.

  18. Device, Interface, Process and Electrode Engineering Towards Low Cost and High Efficiency Polymer Solar Cells in Inverted Structure

    NASA Astrophysics Data System (ADS)

    Zou, Jingyu

    As a promising technology for economically viable alternative energy source, polymer solar cells (PSCs) have attracted substantial interests and made significant progress in the past few years, due the advantages of being potentially easily solution processed into large areas, flexible, light weight, and have the versatility of material design. In this dissertation, an integrated approach is taken to improve the overall performance of polymer solar cells by the development of new polymer materials, device architectures, interface engineering of the contacts between layers, and new transparent electrodes. First, several new classes of polymers are explored as potential light harvesting materials for solar cells. Processing has been optimized and efficiency as high as 6.24% has been demonstrated. Then, with the development of inverted device structure, which has better air stability by utilizing more air stable, high work function metals, newly developed high efficiency polymers have been integrated into inverted structure device with integrated engineering approach. A comprehensive characterization and optical modeling based on conventional and inverted devices have been performed to understand the effect of device geometry on photovoltaic performance based on a newly developed high performance polymer poly(indacenodithiophene-co-phananthrene-quinoxaline) (PIDT-PhanQ). By modifying anode with a bilayer combining graphene oxide (GO) and poly(3,4-ethylenedioxylenethiophene):poly(styrenesulfonic acid) (PEDOT:PSS) as hole transporter/electron blocker, it further improved device performance of inverted structured to 6.38%. A novel processing method of sequentially bilayer deposition for active layer has been conducted based on a low band-gap polymer poly[2, 6-(4, 4-bis-(2-ethylhexyl)-4 H-cyclopenta [2,1-b;3,4-b‧] dithiophene)- alt-4,7-(2, 1, 3- fluorobenzothiadiazole)] (PCPDT-FBT). Inverted structure devices processed from bilayer deposition shows even higher

  19. Simulation of the Densification of Semicrystalline Polymer Powders during the Selective Laser Sintering Process: Application to Nylon-12,

    SciTech Connect

    Dong, L.; Makradi, A.; Ahzi, Said; Remond, Y.; Sun, Xin

    2008-06-01

    The heating and densification processes of semi-crystalline polymer powders, during the selective laser sintering process, are simulated using the finite element method. Based on previously developed three-dimensional approach for the sintering of amorphous polymer powders, the modeling methodology is extended to semi-crystalline polymers by taking into account the effects of latent heat during melting. In these simulations, the temperature dependent thermal conductivity, specific heat, density and the effect of latent heat are computed then used as material constants for the integration of the heat equation. Results for temperature and density distribution using Nylon-12 powder are presented and discussed. The effects of processing parameters on the density distribution are also presented.

  20. Low-temperature baroplastic processing of graphene-based polymer composites by pressure-induced flow

    NASA Astrophysics Data System (ADS)

    Tang, Wei; He, Cheng-en; Wang, Yuanzhen; Yang, Yingkui; Pong Tsui, Chi

    2014-08-01

    Two-stage emulsion polymerization was employed to synthesize nanoparticles consisting of a low glass transition temperature core of poly(n-butyl acrylate) (PBA) and a glassy poly(methyl methylacrylate) (PMMA) shell. Incorporation of graphene oxide (GO) into the PBA-PMMA latex produced GO/PBA-PMMA composites after demulsification and graphene/PBA-PMMA composites after chemical reduction of GO. The as-prepared powdery materials were processed into thin films by compression molding at room temperature as the result of a pressure-induced mixing mechanism of microphase-separated baroplastics. The presence of oxygen-containing groups for GO sheets contributed to better dispersion and stronger interface with the matrix, thereby showing greater reinforcement efficiency toward polymers compared to graphene sheets. In addition, both Young's modulus and yield strength for all materials increased with applied pressure and processing time due to better flowability, processability and cohesion at higher pressure and longer time. Low-temperature processing under pressure is of significance for energy conservation, recyclability and environmental protection during plastic processing.

  1. Study of the sorption processes in a piezoelectric-molecularly imprinted polymer film structure using Rayleigh surface acoustic waves

    NASA Astrophysics Data System (ADS)

    Kryshtal, R. G.; Medved', A. V.

    2009-09-01

    The sorption processes in a piezoelectric-molecularly imprinted polymer film structure, where the polymer is synthesized from the monomers of bisphenol-A glycerolate diacrylate using imprinted morpholine molecules as template molecules, are experimentally studied with Rayleigh surface acoustic waves at a frequency of 120 MHz. The desorption processes for morpholine are found to be anomalously slow as compared to other analytes under study. The possibility of the application of the results obtained for creating selective chemical sensors based on surface acoustic waves is discussed.

  2. Solution-processed low dimensional nanomaterials with self-assembled polymers for flexible photo-electronic devices (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Park, Cheolmin

    2015-09-01

    Self assembly driven by complicated but systematic hierarchical interactions offers a qualified alternative for fabricating functional micron or nanometer scale pattern structures that have been potentially useful for various organic and nanotechnological devices. Self assembled nanostructures generated from synthetic polymer systems such as controlled polymer blends, semi-crystalline polymers and block copolymers have gained a great attention not only because of the variety of nanostructures they can evolve but also because of the controllability of these structures by external stimuli. In this presentation, various novel photo-electronic materials and devices are introduced based on the solution-processed low dimensional nanomaterials such as networked carbon nanotubes (CNTs), reduced graphene oxides (rGOs) and 2 dimensional transition metal dichalcogenides (TMDs) with self assembled polymers including field effect transistor, electroluminescent device, non-volatile memory and photodetector. For instance, a nanocomposite of networked CNTs and a fluorescent polymer turned out an efficient field induced electroluminescent layer under alternating current (AC) as a potential candidate for next generation displays and lightings. Furthermore, scalable and simple strategies employed for fabricating rGO as well as TMD nanohybrid films allowed for high performance and mechanically flexible non-volatile resistive polymer memory devices and broad band photo-detectors, respectively.

  3. Purification and processing of carbon nanotubes using self-assembly and selective interaction with a semiconjugated polymer

    NASA Astrophysics Data System (ADS)

    Fournet, Patrick; McCarthy, Brendan; Dalton, Alan B.; Coleman, Jonathan N.; Murphy, Robert J.; Stephan, Christophe; Lefrant, Serge; Bernier, Patrick; Byrne, Hugh J.; Blau, Werner J.

    2001-12-01

    A new route for nanotube-based applications in molecular electronics was developed. Individual polymer strands were assembled onto single-walled carbon nanotubes (SWNT) and multi-walled carbon nanotubes (MWNT) by mechanical agitation. The SWNT hybrid systems have been characterized by electron microscopy (TEM, STM), optical absorption and Raman spectroscopy and a fully nondestructive technique, using electron paramagnetic resonance (EPR), has been developed to estimate the purity of MWNT soot and hybrids. It is demonstrated that solutions of the polymer are capable of suspending nanotubes indefinitely while the majority of the accompanying amorphous graphite precipitates out of solution. Electron microscopy and Raman scattering indicate that through an intercalation process, the ropes of SWNT are destroyed, resulting in individual nanotubes being well dispersed within the polymer matrix. Moreover, Raman and absorption studies suggest that the polymer interacts preferentially with nanotubes of specific diameters or a range of diameters. STM studies showed that the chiral angle of the underlying nanotube is reflected in the polymer coating, demonstrating that the lattice structure of the SWNT templates the ordering in the coating. This could lead to design of specific polymer architectures for selection of desired chiral angles, and hence specific electronic properties.

  4. High-Performance Thin Film Transistor from Solution-Processed P3HT Polymer Semiconductor Nanoparticles

    NASA Astrophysics Data System (ADS)

    Darwis, Darmawati; Elkington, Daniel; Ulum, Syahrul; Stapleton, Andrew; Bryant, Glenn; Zhou, Xiaojing; Belcher, Warwick; Dastoor, Paul

    2011-12-01

    Nanoparticulate suspensions of semiconducting polymer poly-3-hexylthiophene (P3HT) have been prepared in water through a mini-emulsion process using sodium dodecyl sulphate (SDS) as the surfactant. Using these suspensions, we have fabricated organic thin film transistors (OTFTs) in a top gate configuration. These devices operate at a low voltage and show output characteristics similar to those achieved when the P3HT film is spun from chloroform. To characterize the properties of the film made from the nanoparticle suspension, differential thermal analysis (TGA), differential scanning calorimetry (DSC), atomic force microscopy (AFM), fluorescence spectra analysis, ultraviolet/visible (UV/VIS) spectrophotometry and X-ray photoelectron spectroscopy (XPS) have been used.

  5. Tuning the Microcavity of Organic Light Emitting Diodes by Solution Processable Polymer-Nanoparticle Composite Layers.

    PubMed

    Preinfalk, Jan B; Schackmar, Fabian R; Lampe, Thomas; Egel, Amos; Schmidt, Tobias D; Brütting, Wolfgang; Gomard, Guillaume; Lemmer, Uli

    2016-02-01

    In this study, we present a simple method to tune and take advantage of microcavity effects for an increased fraction of outcoupled light in solution-processed organic light emitting diodes. This is achieved by incorporating nonscattering polymer-nanoparticle composite layers. These tunable layers allow the optimization of the device architecture even for high film thicknesses on a single substrate by gradually altering the film thickness using a horizontal dipping technique. Moreover, it is shown that the optoelectronic device parameters are in good agreement with transfer matrix simulations of the corresponding layer stack, which offers the possibility to numerically design devices based on such composite layers. Lastly, it could be shown that the introduction of nanoparticles leads to an improved charge injection, which combined with an optimized microcavity resulted in a maximum luminous efficacy increase of 85% compared to a nanoparticle-free reference device.

  6. Solution-processed parallel tandem polymer solar cells using silver nanowires as intermediate electrode.

    PubMed

    Guo, Fei; Kubis, Peter; Li, Ning; Przybilla, Thomas; Matt, Gebhard; Stubhan, Tobias; Ameri, Tayebeh; Butz, Benjamin; Spiecker, Erdmann; Forberich, Karen; Brabec, Christoph J

    2014-12-23

    Tandem architecture is the most relevant concept to overcome the efficiency limit of single-junction photovoltaic solar cells. Series-connected tandem polymer solar cells (PSCs) have advanced rapidly during the past decade. In contrast, the development of parallel-connected tandem cells is lagging far behind due to the big challenge in establishing an efficient interlayer with high transparency and high in-plane conductivity. Here, we report all-solution fabrication of parallel tandem PSCs using silver nanowires as intermediate charge collecting electrode. Through a rational interface design, a robust interlayer is established, enabling the efficient extraction and transport of electrons from subcells. The resulting parallel tandem cells exhibit high fill factors of ∼60% and enhanced current densities which are identical to the sum of the current densities of the subcells. These results suggest that solution-processed parallel tandem configuration provides an alternative avenue toward high performance photovoltaic devices. PMID:25405589

  7. Differential-Integral method in polymer processing: Taking melt electrospinning technique for example

    NASA Astrophysics Data System (ADS)

    Haoyi, Li; Weimin, Yang; Hongbo, Chen; Jing, Tan; Pengcheng, Xie

    2016-03-01

    A concept of Differential-Integral (DI) method applied in polymer processing and molding was proposed, which included melt DI injection molding, DI nano-composites extrusion molding and melt differential electrospinning principle and equipment. Taking the melt differential electrospinning for example to introduce the innovation research progress, two methods preparing polymer ultrafine fiber have been developed: solution electro-spinning and melt electro-spinning, between which solution electro-spinning is much simpler to realize in lab. More than 100 institutions have endeavored to conduct research on it and more than 30 thousand papers have been published. However, its industrialization was restricted to some extend because of the existence of toxic solvent during spinning process and poor mechanical strength of resultant fibers caused by small pores on fiber surface. Solvent-free melt electrospinning is environmentally friendly and highly productive. However, problems such as the high melt viscosity, thick fiber diameter and complex equipment makes it relatively under researched compared with solution electrospinning. With the purpose of solving the shortage of traditional electro-spinning equipment with needles or capillaries, a melt differential electro-spinning method without needles or capillaries was firstly proposed. Nearly 50 related patents have been applied since 2005, and systematic method innovations and experimental studies have also been conducted. The prepared fiber by this method had exhibited small diameter and smooth surface. The average fiber diameter can reach 200-800 nm, and the single nozzle can yield two orders of magnitude more than the capillaries. Based on the above principle, complete commercial techniques and equipment have been developed to produce ultra-fine non-woven fabrics for the applications in air filtration, oil spill recovery and water treatment, etc.

  8. ARTICLE Molecular Dynamic Simulation on the Absorbing Process of Isolating and Coating of α-olefin Drag Reducing Polymer

    NASA Astrophysics Data System (ADS)

    Li, Bing; Sheng, Xiang; Xing, Wen-guo; Dong, Gui-lin; Liu, Yong-jun; Zhang, Chang-qiao; Chen, Xiang-jun; Zhou, Ning-ning; Qin, Zhan-bo

    2010-12-01

    The absorbing process in isolating and coating process of α-olefin drag reducing polymer was studied by molecular dynamic simulation method, on basis of coating theory of α-olefin drag reducing polymer particles with polyurethane as coating material. The distributions of sodium laurate, sodium dodecyl sulfate, and sodium dodecyl benzene sulfonate on the surface of α-olefin drag reducing polymer particles were almost the same, but the bending degrees of them were obviously different. The bending degree of SLA molecules was greater than those of the other two surfactant molecules. Simulation results of absorbing and accumulating structure showed that, though hydrophobic properties of surfactant molecules were almost the same, water density around long chain sulfonate sodium was bigger than that around alkyl sulfate sodium. This property goes against useful absorbing and accumulating on the surface of α-olefin drag reducing polymer particles; simulation results of interactions of different surfactant and multiple hydroxyl compounds on surface of particles showed that, interactions of different surfactant and one kind of multiple hydroxyl compound were similar to those of one kind of surfactant and different multiple hydroxyl compounds. These two contrast types of interactions also exhibited the differences of absorbing distribution and closing degrees to surface of particles. The sequence of closing degrees was derived from simulation; control step of addition polymerization interaction in coating process was absorbing mass transfer process, so the more closed to surface of particle the multiple hydroxyl compounds were, the easier interactions with isocyanate were. Simulation results represented the compatibility relationship between surfactant and multiple hydroxyl compounds. The isolating and coating processes of α-olefin drag reducing polymer were further understood on molecule and atom level through above simulation research, and based on the simulation, a

  9. Implementation of New Process Models for Tailored Polymer Composite Structures into Processing Software Packages

    SciTech Connect

    Nguyen, Ba Nghiep; Jin, Xiaoshi; Wang, Jin; Phelps, Jay; Tucker III, Charles L.; Kunc, Vlastimil; Bapanapalli, Satish K.; Smith, Mark T.

    2010-02-23

    This report describes the work conducted under the Cooperative Research and Development Agreement (CRADA) (Nr. 260) between the Pacific Northwest National Laboratory (PNNL) and Autodesk, Inc. to develop and implement process models for injection-molded long-fiber thermoplastics (LFTs) in processing software packages. The structure of this report is organized as follows. After the Introduction Section (Section 1), Section 2 summarizes the current fiber orientation models developed for injection-molded short-fiber thermoplastics (SFTs). Section 3 provides an assessment of these models to determine their capabilities and limitations, and the developments needed for injection-molded LFTs. Section 4 then focuses on the development of a new fiber orientation model for LFTs. This model is termed the anisotropic rotary diffusion - reduced strain closure (ARD-RSC) model as it explores the concept of anisotropic rotary diffusion to capture the fiber-fiber interaction in long-fiber suspensions and uses the reduced strain closure method of Wang et al. to slow down the orientation kinetics in concentrated suspensions. In contrast to fiber orientation modeling, before this project, no standard model was developed to predict the fiber length distribution in molded fiber composites. Section 5 is therefore devoted to the development of a fiber length attrition model in the mold. Sections 6 and 7 address the implementations of the models in AMI, and the conclusions drawn from this work is presented in Section 8.

  10. Microfabrication of Super Absorbent Polymer Structure Using Nanoimprinting and Swelling Process

    NASA Astrophysics Data System (ADS)

    Inaba, Tomomi; Kano, Tomonori; Miki, Norihisa

    2013-06-01

    Micro-fabrication technologies have been extensively studied to achieve smaller sizes and higher aspect ratios. When the features have sizes of a couple of micrometers or below, nano-imprinting can be an effective method for micro-fabrication at low cost. However, it is difficult to achieve aspect ratio greater than 1. In this research, we propose micro fabrication of super absorbent polymer (SAP) as a new material for micro devices. SAP swells by adding deionized water, which can be used as a post patterning process to enhance the aspect ratio of micro structures. Micropatterning of SAP must be conducted under thoroughly dry conditions and we used nano-imprinting processes. We successfully augmented an aspect ratio of the nano-imprinted micro holes of SAP from 0.65 to 1.2 by the swelling process. The proposed patterning and swelling process of SAP can be applicable to micro-fabricate high-aspect-ratio structures at low cost for high performance lab-on-a-chip.

  11. Real-time process monitoring and temperature mapping of a 3D polymer printing process

    NASA Astrophysics Data System (ADS)

    Dinwiddie, Ralph B.; Love, Lonnie J.; Rowe, John C.

    2013-05-01

    An extended-range IR camera was used to make temperature measurements of samples as they are being manufactured. The objective is to quantify the temperature variation of the parts as they are being fabricated. The IR camera was also used to map the temperature within the build volume of the oven. The development of the temperature map of the oven provides insight into the global temperature variation within the oven that may lead to understanding variations in the properties of parts as a function of build location within the oven. The observation of the temperature variation of a part during construction provides insight into how the deposition process itself creates temperature distributions, which can lead to failure.

  12. Real-time Process Monitoring and Temperature Mapping of the 3D Polymer Printing Process

    SciTech Connect

    Dinwiddie, Ralph Barton; Love, Lonnie J; Rowe, John C

    2013-01-01

    An extended range IR camera was used to make temperature measurements of samples as they are being manufactured. The objective is to quantify the temperature variation inside the system as parts are being fabricated, as well as quantify the temperature of a part during fabrication. The IR camera was used to map the temperature within the build volume of the oven and surface temperature measurement of a part as it was being manufactured. The development of the temperature map of the oven provides insight into the global temperature variation within the oven that may lead to understanding variations in the properties of parts as a function of location. The observation of the temperature variation of a part that fails during construction provides insight into how the deposition process itself impacts temperature distribution within a single part leading to failure.

  13. Piling-to-buckling transition in the drying process of polymer solution drop on substrate having a large contact angle

    NASA Astrophysics Data System (ADS)

    Kajiya, Tadashi; Nishitani, Eisuke; Yamaue, Tatsuya; Doi, Masao

    2006-01-01

    We studied the drying process of polymer solution drops placed on a substrate having a large contact angle with the drop. The drying process takes place in three stages. First, the droplet evaporates keeping the contact line fixed. Second, the droplet shrinks uniformly with receding contact line. Finally the contact line is pinned again, and the droplet starts to be deformed. The shape of the final polymer deposit changes from concave dot, to flat dot, and then to concave dot again with the increase of the initial polymer concentration. This shape change is caused by the gradual transition from the solute piling mechanism proposed by Deegan to the crust buckling mechanism proposed by de Gennes and Pauchard.

  14. Integrated all-polymer Mach-Zehnder interferometers without interaction window in asymmetric configuration

    NASA Astrophysics Data System (ADS)

    Xiao, Yanfen; Hofmann, Meike; Wang, Ziyu; Sherman, Stanislav; Li, Pei; Zappe, Hans

    2016-02-01

    Integrated Mach-Zehnder interferometers (MZI) based on semiconductors or glasses have been widely used as evanescent field sensors for the monitoring of liquid or gas concentrations. In these systems the upper cladding of the sensing arm is removed partially to form an interaction window by means of subtractive fabrication techniques like etching. The use of polymer materials implicates new options and challenges. Polymers are tunable in terms of refractive index and viscosity offering a great flexibility in design and fabrication in a certain range. They enable a cost-efficient and large-scale roll-to-roll manufacturing of integrated optics on flexible foils as substrate material. The foils can be pre-patterned for example by hot-embossing. Additive steps such as printing a pattern or dispensing a homogeneous layer of liquid monomer material followed by a UV induced polymerization can be used to define the optical structure. However, when a large scale fabrication is required, the reliable production of small lateral structures and thin layers is challenging. Thus the fabrication according to the classical MZI design including an interaction window is difficult so that new design approaches are required. We present here the design and systematic evaluation of MZI sensors without interaction window based on polymer materials. The phase shift at the recombining Y-splitter of the MZI upon a refractive index change of an analyte, which serves as upper cladding of the entire system, is generated by a geometrical asymmetricity of the MZI. The waveguides in the sensing and the reference arm have different width leading to different effective refractive indices and sensitivities. We consider theoretically the expected interference signal and show results from numerical simulations of the whole system using commercial software. The simulations include the material as well as propagation losses and give an overall optimal system length.

  15. Effect of polymer matrix on structure of Se particles formed in aqueous solutions during redox process

    SciTech Connect

    Suvorova, E. I. Klechkovskaya, V. V.

    2010-12-15

    Transmission electron microscopy and X-ray energy dispersive microanalysis study of the structure of particles formed during the reduction of Se(IV) to Se(0) in aqueous solutions in the presence of amphiphilic polymers showed the formation of Se/polymer composite particles. The content of carbon inside the particles can be as large as 80 at %. Polymers deeply influence the structure of particles. Depending on polymers, the composite particles may be unstable with time and they spontaneously evolve from Se/polymer composite particles to crystalline particles of monoclinic Se. For the stable ones, addition of bacterial cellulose Acetobacter xylinum gel-film can induce crystallization in the particles which expel the polymeric material. The Se/polymer composite particles and Se crystalline particles exhibit different sensitivity to electron irradiation and stiffness.

  16. Chemical and physical processes in the retention of functional groups in plasma polymers studied by plasma phase mass spectroscopy.

    PubMed

    Ryssy, Joonas; Prioste-Amaral, Eloni; Assuncao, Daniela F N; Rogers, Nicholas; Kirby, Giles T S; Smith, Louise E; Michelmore, Andrew

    2016-02-14

    Surface engineering of functionalised polymer films is a rapidly expanding field of research with cross disciplinary implications and numerous applications. One method of generating functionalised polymer films is radio frequency induced plasma polymerisation which provides a substrate independent coating. However, there is currently limited understanding surrounding chemical interactions in the plasma phase and physical interactions at the plasma-surface interface, and their effect on functional group retention in the thin film. Here we investigate functionalised plasma polymer films generated from four precursors containing primary amines. Using XPS and fluorine tagging with 4-(trifluoromethyl)benzaldehyde, the primary amine content of plasma polymer films was measured as a function of applied power at constant precursor pressure. The results were then correlated with analysis of the plasma phase by mass spectrometry which showed loss of amine functionality for both neutral and ionic species. Surface interactions are also shown to decrease primary amine retention due to abstraction of hydrogen by high energy ion impacts. The stability of the plasma polymers in aqueous solution was also assessed and is shown to be precursor dependent. Increased understanding of the chemical and physical processes in the plasma phase and at the surface are therefore critical in designing improved plasma polymerisation processes. PMID:26791435

  17. Liquid PEG Polymers Containing Antioxidants: A Versatile Platform for Studying Oxygen-Sensitive Photochemical Processes.

    PubMed

    Mongin, Cédric; Golden, Jessica H; Castellano, Felix N

    2016-09-14

    This article proposes the exploitation of widely available, inexpensive, innocuous "green" liquid polyethylene glycol (PEG) polymers containing the oxygen scavenger oleic acid (OA) as promising media for studying oxygen-sensitive photochemical processes. Here we report the successful application of this media to detailed investigations of triplet-sensitized photochemical upconversion, previously established as being readily poisoned by dissolved oxygen. Three different PEG materials were investigated with increasing molecular weight from 200 to 600 g/mol, coded as PEG-200, PEG-400, and PEG-600. These fluidic polymers facilitate an oxygen-depleted environment in comparison to commonly employed organic solvents while providing high solubility and diffusion for the dissolved chromophores. Moreover, the low oxygen permeation afforded by these PEG solvents allows them to remain deoxygenated in open containers under ambient conditions for extended time periods. OA, 9,10-dimethylanthracene (DMA), and 2,5-dimethylfuran (DMF) are shown to efficiently and quantitatively consume dissolved oxygen in the PEG environment in the presence of the photoactivated triplet sensitizer platinum(II) tetraphenyltetrabenzoporphyrin (PtTPBP). Oxygen consumption was directly correlated with systematically increasing sensitizer excited-state lifetimes that eventually reach the same plateau as achieved through extensive N2 sparging. Diffusion-controlled bimolecular triplet-triplet energy transfer quenching between PtTPBP and the acceptor/annihilator 9,10-bisphenylethynylanthracene (BPEA) was observed in all three PEG formulations investigated. Subsequent triplet-triplet annihilation, between triplet excited BPEA acceptors, achieves bright and stable upconverted singlet fluorescence from BPEA with no decrease in intensity over 20 h under ambient conditions. In the champion composition (PEG 200), the upconversion quantum efficiency reached 31% under conditions where triplet-triplet annihilation

  18. Polymer Chemistry

    NASA Technical Reports Server (NTRS)

    Williams, Martha; Roberson, Luke; Caraccio, Anne

    2010-01-01

    This viewgraph presentation describes new technologies in polymer and material chemistry that benefits NASA programs and missions. The topics include: 1) What are Polymers?; 2) History of Polymer Chemistry; 3) Composites/Materials Development at KSC; 4) Why Wiring; 5) Next Generation Wiring Materials; 6) Wire System Materials and Integration; 7) Self-Healing Wire Repair; 8) Smart Wiring Summary; 9) Fire and Polymers; 10) Aerogel Technology; 11) Aerogel Composites; 12) Aerogels for Oil Remediation; 13) KSC's Solution; 14) Chemochromic Hydrogen Sensors; 15) STS-130 and 131 Operations; 16) HyperPigment; 17) Antimicrobial Materials; 18) Conductive Inks Formulations for Multiple Applications; and 19) Testing and Processing Equipment.

  19. Fluorescence spectral changes of perylene in polymer matrices during the solvent evaporation process.

    PubMed

    Ito, Fuyuki; Kogasaka, Yoshiko; Yamamoto, Kazuki

    2013-04-01

    This work examined concentration-dependent variations in the fluorescence spectra of solutions of perylene and PMMA in toluene during the process of evaporation, using fluorescence microscopy. At low perylene concentrations, the fluorescence spectra of the resulting perylene/PMMA films exhibited a structural band originating from monomeric perylene. Increasing the concentration resulted in the appearance of new, broader bands due to the formation of two excimer species. An estimation of variations in the fluorescence excitation spectra of these same films with changing concentration and excitation wavelength indicated the formation from monomer to fully overlapped excimer via partially overlapped excimer in terms of the kinetic situation. These species are believed to consist of either ground state aggregates or α-crystals resulting from phase separation within the PMMA films. Dynamic fluorescence changes during solvent evaporation were monitored by fluorescence spectroscopy and CCD photography. Fluorescence emission changed from blue to green with the formation of α-crystals, a pattern which was also observed when increasing perylene concentrations in PMMA films during static trials. The concentration distribution around α-crystals was attributed to the crystal growth process and could be followed by observing the fluorescence color gradient radiating from the crystal. Studying concentration-dependent fluorescence spectral changes during solvent evaporation not only provides insight into the molecular dynamics of the casting process and the compatibility between the dispersed material and the polymer matrix but also provides information concerning molecular assembly and the nucleation and growth of crystals of the fluorescent organic molecules.

  20. Solution processable organic polymers and small molecules for bulk-heterojunction solar cells: A review

    SciTech Connect

    Sharma, G. D.

    2011-10-20

    Solution processed bulk heterojunction (BHJ) organic solar cells (OSCs) have gained wide interest in past few years and are established as one of the leading next generation photovoltaic technologies for low cost power production. Power conversion efficiencies up to 6% and 6.5% have been reported in the literature for single layer and tandem solar cells, respectively using conjugated polymers. A recent record efficiency about 8.13% with active area of 1.13 cm{sup 2} has been reported. However Solution processable small molecules have been widely applied for photovoltaic (PV) devices in recent years because they show strong absorption properties, and they can be easily purified and deposited onto flexible substrates at low cost. Introducing different donor and acceptor groups to construct donor--acceptor (D--A) structure small molecules has proved to be an efficient way to improve the properties of organic solar cells (OSCs). The power conversion efficiency about 4.4 % has been reported for OSCs based on the small molecules. This review deals with the recent progress of solution processable D--A structure small molecules and discusses the key factors affecting the properties of OSCs based on D--A structure small molecules: sunlight absorption, charge transport and the energy level of the molecules.

  1. Recent developments in the application of electron accelerators for polymer processing

    NASA Astrophysics Data System (ADS)

    Chmielewski, A. G.; Al-Sheikhly, M.; Berejka, A. J.; Cleland, M. R.; Antoniak, M.

    2014-01-01

    There are now over 1700 high current, electron beam (EB) accelerators being used world-wide in industrial applications, most of which involve polymer processing. In contrast to the use of heat, which transfers only about 5-10% of input energy into energy useful for materials modification, radiation processing is very energy efficient, with 60% or more of the input energy to an accelerator being available for affecting materials. Historic markets, such as the crosslinking of wire and cable jacketing, of heat shrinkable tubings and films, of partial crosslinking of tire components and of low-energy EB to cure or dry inks and coatings remain strong. Accelerator manufacturers have made equipment more affordable by down-sizing units while maintaining high beam currents. Very powerful accelerators with 700 kW output have made X-ray conversion a practical alternative to the historic use of radioisotopes, mainly cobalt-60, for applications as medical device sterilization. New EB end-uses are emerging, such as the development of nano-composites and nano-gels and the use of EB processing to facilitate biofuel production. These present opportunities for future research and development.

  2. Ultrafast Electronic Processes At Semiconductor Polymer Heterojunctions: A Molecular-Level, Quantum-Dynamical Analysis

    SciTech Connect

    Burghardt, I.; Tamura, H.; Bittner, E. R.

    2009-03-09

    This contribution gives an overview of our recent study of phonon-driven exciton dissociation at semiconductor polymer heterojunctions, using a quantum dynamical analysis based on a linear vibronic coupling model parametrized for three electronic states and 20-30 phonon modes. The decay of the photogenerated exciton towards an interfacial charge transfer state is an ultrafast (femtosecond to picosecond scale) process which initiates the photocurrent generation. We consider several representative interface configurations, which are shown to exhibit an efficient exciton dissociation. The process depends critically on the presence of intermediate states, and on the dynamical interplay between high-frequency (C=C stretch) and low-frequency (ring-torsional) modes. The dynamical mechanism is interpreted in terms of a hierarchical electron-phonon model which allows one to identify generalized reaction coordinates for the nonadiabatic process. This analysis highlights that the electron-phonon coupling is dominated by the high-frequency modes, but the low-frequency modes are crucial in mediating the transition to a charge-separated state. The ultra-fast, highly nonequilibrium dynamics is in accordance with spectroscopic observations.

  3. Oriented hydroxyapatite in turkey tendon mineralized via the polymer-induced liquid-precursor (PILP) process

    SciTech Connect

    Jee, S.S.; DiMasi, E.; Kasinath, R.K.; Kim, Y.Y.; Gower, L.

    2010-12-03

    Bone is a hierarchically structured composite which imparts it with unique mechanical properties and bioresorptive potential. These properties are primarily influenced by the underlying nanostructure of bone, which consists of nanocrystals of hydroxyapatite embedded and uniaxially aligned within collagen fibrils. There is also a small fraction of non-collagenous proteins in bone, and these are thought to play an important role in bone's formation. In our in vitro model system of bone formation, polyanionic peptides are used to mimic the role of the non-collagenous proteins. In our prior studies, we have shown that intrafibrillar mineralization can be achieved in synthetic reconstituted collagen sponges using a polymer-induced liquid-precursor (PILP) mineralization process. This led to a nanostructured arrangement of hydroxyapatite crystals within the individual fibrils which closely mimics that of bone. This report demonstrates that biogenic collagen scaffolds obtained from turkey tendon, which consist of densely packed and oriented collagen fibrils, can also be mineralized by the PILP process. Synchrotron X-ray diffraction studies show that the mineralization process leads to a high degree of crystallographic orientation at the macroscale, thus emulating that found in the biological system of naturally mineralizing turkey tendon.

  4. Ultrafast Electronic Processes At Semiconductor Polymer Heterojunctions: A Molecular-Level, Quantum-Dynamical Analysis

    NASA Astrophysics Data System (ADS)

    Burghardt, I.; Bittner, E. R.; Tamura, H.

    2009-03-01

    This contribution gives an overview of our recent study of phonon-driven exciton dissociation at semiconductor polymer heterojunctions, using a quantum dynamical analysis based on a linear vibronic coupling model parametrized for three electronic states and 20-30 phonon modes. The decay of the photogenerated exciton towards an interfacial charge transfer state is an ultrafast (femtosecond to picosecond scale) process which initiates the photocurrent generation. We consider several representative interface configurations, which are shown to exhibit an efficient exciton dissociation. The process depends critically on the presence of intermediate states, and on the dynamical interplay between high-frequency (C=C stretch) and low-frequency (ring-torsional) modes. The dynamical mechanism is interpreted in terms of a hierarchical electron-phonon model which allows one to identify generalized reaction coordinates for the nonadiabatic process. This analysis highlights that the electron-phonon coupling is dominated by the high-frequency modes, but the low-frequency modes are crucial in mediating the transition to a charge-separated state. The ultra-fast, highly nonequilibrium dynamics is in accordance with spectroscopic observations.

  5. LIGHT SOURCE: Physical design of a 10 MeV LINAC for polymer radiation processing

    NASA Astrophysics Data System (ADS)

    Feng, Guang-Yao; Pei, Yuan-Ji; Wang, Lin; Zhang, Shan-Cai; Wu, Cong-Feng; Jin, Kai; Li, Wei-Min

    2009-06-01

    In China, polymer radiation processing has become one of the most important processing industries. The radiation processing source may be an electron beam accelerator or a radioactive source. Physical design of an electron beam facility applied for radiation crosslinking is introduced in this paper because of it's much higher dose rate and efficiency. Main part of this facility is a 10 MeV travelling wave electron linac with constant impedance accelerating structure. A start to end simulation concerning the linac is reported in this paper. The codes Opera-3d, Poisson-superfish and Parmela are used to describe electromagnetic elements of the accelerator and track particle distribution from the cathode to the end of the linac. After beam dynamic optimization, wave phase velocities in the structure have been chosen to be 0.56, 0.9 and 0.999 respectively. Physical parameters about the main elements such as DC electron gun, iris-loaded periodic structure, solenoids, etc, are presented. Simulation results proves that it can satisfy the industrial requirement. The linac is under construction. Some components have been finished. Measurements proved that they are in a good agreement with the design values.

  6. Processing and characterization of protein polymer thin films for surface modification of neural prosthetic devices

    NASA Astrophysics Data System (ADS)

    Buchko, Christopher John

    The objective of this research has been to develop methods for modifying the surfaces of neural prosthetic devices to enhance biocompatibility. Also central to this work was the characterization of the processes used to modify the surfaces, the resulting macroscopic and microscopic structure, and the relevant physical properties of the new surface. The application required a coating that could attract and adhere cells, mediate the stiffness mismatch between the device and tissue, and facilitate signal transport from the device to tissue. The materials chosen for use as surface modifiers were genetically engineered polypeptides that combine biofunctional sequences with structural segments, creating a processable bioadhesive agent. An electric field mediated deposition process was used to create thin coatings on the devices from these protein polymers. Varying the process parameters was found to exert controllable changes on the morphology, and porous thin films with a range of structures were fabricated. This deposition process was combined with lithographic techniques to generate high-fidelity patterned surfaces. It was anticipated that the surface structure of these films could augment their biochemical composition and facilitate cell adhesion. A Fourier Transform-based method of explicitly quantifying the surface topography was employed to evaluate the effects of process parameters on topography. The mechanical properties of the coatings were examined to determine a suitable morphology for joining the mechanically dissimilar device and tissue. Fibrous coatings composed of randomly oriented filaments exhibited a stiffness gradient while under compression. The films were compliant near the tissue and stiffer near the device. The biological performance of these films was assayed and the films were seen to be potent cellular adhesives. The coatings were also found to be capable of delivering biologically-relevant molecules in vitro.

  7. Hyaluronic acid auto-crosslinked polymer (ACP): Reaction monitoring, process investigation and hyaluronidase stability.

    PubMed

    Pluda, Stefano; Pavan, Mauro; Galesso, Devis; Guarise, Cristian

    2016-10-01

    Hyaluronic Acid (HA) is a non-sulphated glycosaminoglycan that, despite its high molecular weight, is soluble in water and is not resistant to enzymatic degradation, the latter of which hinders its wider application as a biomedical material. Auto-crosslinked polymer (ACP) gels of HA are fully biocompatible hydrogels that exhibit improved viscoelastic properties and prolonged in vivo residence times compared to the native polymer. Crosslinking is achieved through a base-catalysed reaction consisting of the activation of HA carboxyl groups by 2-chloro-1-methylpyridinium iodide (CMPI) and subsequent nucleophilic acyl substitution by the hydroxyl groups of HA in organic solvent. In this study, a number of ACP hydrogels have been obtained via reactions using varying ratios of CMPI to HA. The crosslinking reaction was monitored by rheological measurements in organic solvents during CMPI addition to the reaction mixture. The ACP intermediates, powders and hydrogels were characterized, helping to elucidate the crosslinking process. A two-step mechanism was proposed to explain the observed trends in viscosity and particle size. Syntheses were carried out by varying the reaction temperature, respectively at 0 °C, 25 °C and 45 °C in N-Methyl-2-Pyrrolidone (NMP), as well as the solvent respectively in NMP, DMSO and DMF at 25 °C. Interestingly, varying these parameters did not substantially affect the degree of crosslinking but likely did influence the intra/inter-molecular crosslinking ratio and, therefore, the viscoelastic properties. A wide range of crosslinking densities was confirmed through ESEM analysis. Finally, a comparative hyaluronidase degradation assay revealed that the ACPs exhibited a higher resistance toward enzymatic cleavage at low elastic modulus compared to other more chemically resistant, crosslinked HAs. These observations demonstrated the importance of crosslinking density of matrix structures on substrate availability. PMID:27442913

  8. Mechanical Properties of Solution-Processed Small-Molecule Semiconductor Films.

    PubMed

    Rodriquez, Daniel; Savagatrup, Suchol; Valle, Eduardo; Proctor, Christopher M; McDowell, Caitlin; Bazan, Guillermo C; Nguyen, Thuc-Quyen; Lipomi, Darren J

    2016-05-11

    Advantages of semiconducting small molecules-as opposed to semiconducting polymers-include synthetic simplicity, monodispersity, low cost, and ease of purification. One purported disadvantage of small-molecule films is reduced mechanical robustness. This paper measures the tensile modulus and crack-onset strain for pure films of the high-performance solution-processable small-molecule donors 7,7'-[4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b']dithiophene-2,6-diyl]bis[6-fluoro-4-(5'-hexyl-[2,2'-bithiophen]-5-yl)benzo[c][1,2,5]thiadiazole] (DTS(FBTTh2)2), 2,5-di(2-ethylhexyl)-3,6-bis(5″-n-hexyl-[2,2',5',2″]terthiophen-5-yl)-pyrrolo[3,4-c]pyrrole-1,4-dione (SMDPPEH), and 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene), the acceptor 5,5'-(2,1,3-benzothiadiazole-4,7-diyldi-2,1-ethenediyl)bis[2-hexyl-1H-isoindole-1,3(2H)-dione] (HPI-BT), blends of DTS(FBTTh2)2 and SMDPPEH with [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) and with HPI-BT, and bulk heterojunction films processed with the additives 1,8-diiodooctane (DIO) and polystyrene (PS). The most deformable films of solution-processed organic semiconductors are found to exhibit tensile moduli and crack-onset strains comparable to those measured for conjugated polymers. For example, the tensile modulus of as-cast DTS(FBTTh2)2 is 0.68 GPa (i.e., comparable to poly(3-hexylthiophene) (P3HT), the common polymer), while it exhibits no cracks when stretched on an elastomeric substrate to strains of 14%. While this high degree of stretchability is lost upon the addition of PC71BM (4.2 GPa, 1.42%), it can be partially recovered using processing additives. Tensile modulus and crack-onset strain are highly correlated, which is typical of van der Waals solids. Increased surface roughness was correlated to increased modulus and brittleness within films of similar composition. Decreased stiffness for soluble molecular semiconductors can be rationalized by the presence of alkyl side chains, which decrease the

  9. Molding mineral within microporous hydrogels by a polymer-induced liquid-precursor (PILP) process.

    PubMed

    Cheng, Xingguo; Gower, Laurie B

    2006-01-01

    Natural biominerals often have exquisite morphologies, where the cells exercise a high degree of crystallographic control through secretion of biological macromolecules and regulation of ion transport. One important example is the sea urchin spine. It has recently been shown to be formed through deposition of a transient amorphous calcium carbonate (ACC) precursor phase that later transforms to single-crystalline calcite, ultimately forming an elaborate three-dimensional microporous calcium carbonate structure with interconnected pores. Macromolecules associated with the mineral phase are thought to play a key role in regulating this transformation. The work described here mimics this type of morphological control by "molding" an amorphous calcium carbonate precursor within a porous poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogel that has been prepared as a negative replica from the void space of an urchin spine. Using an acidic biomimetic polymer as a process-directing agent, we show that polyaspartic acid induces amorphous calcium carbonate (ACC) nanoparticles, which have fluidic character and therefore are able to infiltrate the PHEMA hydrogel replica and coalesce into the convoluted morphology that replicates the original microporous structure of the sea urchin spine. By "molding" calcium carbonate into a complex morphology at room temperature, using a precursor process that is induced by a biomimetic acidic macromolecule, the PILP process is a useful in vitro model for examining different aspects of the amorphous-to-crystalline transformation process that is apparently used by a variety of biomineralizing organisms. For example, although we were able to replicate the overall morphology of the spine, it had polycrystalline texture; further studies with this system will focus on controlling the nucleation event, which may help to elucidate how such a convoluted structure can be prepared with single-crystalline texture via an amorphous precursor. Through a

  10. Preparation of organic/inorganic composite membranes using two types of polymer matrix via a sol-gel process

    NASA Astrophysics Data System (ADS)

    Park, Seung-Hee; Park, Jin-Soo; Yim, Sung-Dae; Park, Seok-Hee; Lee, Young-Moo; Kim, Chang-Soo

    Organic/inorganic composite membranes were prepared using two different polymers. BPO 4 particles were introduced into polymers via an in situ sol-gel process. Pre-/post-sulfonated polymers were used to prepare composite membranes as matrix. Pre-sulfonated poly(aryl ether ketone) (SPAEK-6F) copolymer was synthesized via nucleophilic aromatic substitution. Degree of sulfonation was adjusted by the percentage of sulfonated monomer. Post-sulfonated poly(ether ether ketone) (SPEEK) was prepared using concentrated sulfuric acid as sulfonation agent. The membranes were characterized in terms of the ion-exchange capacity (IEC), proton conductivity, water uptake, AFM, SEM and their thermal properties. The SPAEK-6F plain membranes showed higher proton conductivity than that of the SPEEK plain membranes at similar water uptake or IEC due to their structural difference. SEM images of the composite membranes showed that the BPO 4 particles were homogenously dispersed in the polymer matrices and BPO 4 particle size was greatly influenced by polymer matrix. The SPAEK-6F/BPO 4 composite membranes had much smaller BPO 4 particle size than the SPEEK/BPO 4 composite membranes due to well dispersion of BPO 4 sol-like particulates in SPAEK-6F polymer solutions forming more hydrophobic/hydrophilic nanophase than SPEEK polymer solutions. The latter containing a few micrometer-scale BPO 4 particles showed higher proton conductivity than the former containing hundreds nanometer-scale BPO 4 particles at similar water uptake due to the increase in freezable water and effect of particle size.

  11. Phase morphology and orientation development of polymer blends in melt processing

    NASA Astrophysics Data System (ADS)

    Yang, Jinhai

    In this dissertation, we studied phase morphology development of various polymer blends in both extrusion and melt spinning using scanning electron microscopy (SEM) assisted with appropriate etching techniques. Various processing conditions, for example shear or elongation rate, shear or elongation stress, and extrusion die length/diameter ratio were considered. The effects of material characteristics, such as viscosity ratio, miscibility and interfacial tension, were studied. To do this, polymer blends were carefully selected. One isotactic polypropylene was blended with two ethylene butene copolymers (EBM), which had different butene contents. One of the blends was miscible and the other was immiscible. The polypropylene was also blended two ethylene octene copolymers (EOM). The above blends had low interfacial tension and different viscosity ratios. One EBM was blended with two polyamide 12 (PA12) materials. These blends had high interfacial tension and different viscosity ratios. One maleic anhydride grafted ethylene octene copolymer was added into the EBM/PA12 blends to decrease their interfacial tension. Studies were focused on a phenomenon that the dispersed phases in these blends could coalesce into a surface layer in both extrusion and melt spinning. This process was controlled by viscosity ratio, interfacial tension and processing conditions. The orientation development of melt spun fibers of these blends was studied by both wide angle X-ray diffraction (WAXD) and birefringence techniques. The orientation was affected by both blend morphologies and solidification order of the blend individual phases. The phase, which solidifies later in the spinline, did not affect the orientation of the first solidified phase. However, the first solidified phase, if it was continuous phase, could largely suppress the orientation of the second solidified phase. Composite stress analysis explained the different orientation behaviors. Extrusion of a PA12 material through a

  12. Influence of film structure on the dewetting kinetics of thin polymer films in the solvent annealing process.

    PubMed

    Zhang, Huanhuan; Xu, Lin; Lai, Yuqing; Shi, Tongfei

    2016-06-28

    On a non-wetting solid substrate, the solvent annealing process of a thin polymer film includes the swelling process and the dewetting process. Owing to difficulties in the in situ analysis of the two processes simultaneously, a quantitative study on the solvent annealing process of thin polymer films on the non-wetting solid substrate is extremely rare. In this paper, we design an experimental method by combining spectroscopic ellipsometry with optical microscopy to achieve the simultaneous in situ study. Using this method, we investigate the influence of the structure of swollen film on its dewetting kinetics during the solvent annealing process. The results show that for a thin PS film with low Mw (Mw = 4.1 kg mol(-1)), acetone molecules can form an ultrathin enriched layer between the PS film and the solid substrate during the swelling process. The presence of the acetone enriched layer accounts for the exponential kinetic behavior in the case of a thin PS film with low Mw. However, the acetone enriched layer is not observed in the case of a thin PS film with high Mw (Mw = 400 kg mol(-1)) and the slippage effect of polymer chains is valid during the dewetting process. PMID:27254136

  13. Mathematical simulation of thermal decomposition processes in coking polymers during intense heating

    SciTech Connect

    Shlenskii, O.F.; Polyakov, A.A.

    1994-12-01

    Description of nonstationary heat transfer in heat-shielding materials based on cross-linked polymers, mathematical simulation of chemical engineering processes of treating coking and fiery coals, and designing calculations all require taking thermal destruction kinetics into account. The kinetics of chemical transformations affects the substance density change depending on the temperature, the time, the heat-release function, and other properties of materials. The traditionally accepted description of the thermal destruction kinetics of coking materials is based on formulating a set of kinetic equations, in which only chemical transformations are taken into account. However, such an approach does not necessarily agree with the obtained experimental data for the case of intense heating. The authors propose including the parameters characterizing the decrease of intermolecular interaction in a comparatively narrow temperature interval (20-40 K) into the set of kinetic equations. In the neighborhood of a certain temperature T{sub 1}, which is called the limiting temperature of thermal decomposition, a decrease in intermolecular interaction causes an increase in the rates of chemical and phase transformations. The effect of the enhancement of destruction processes has been found experimentally by the contact thermal analysis method.

  14. Porous coordination polymers as novel sorption materials for heat transformation processes.

    PubMed

    Janiak, Christoph; Henninger, Stefan K

    2013-01-01

    Porous coordination polymers (PCPs)/metal-organic frameworks (MOFs) are inorganic-organic hybrid materials with a permanent three-dimensional porous metal-ligand network. PCPs or MOFs are inorganic-organic analogs of zeolites in terms of porosity and reversible guest exchange properties. Microporous water-stable PCPs with high water uptake capacity are gaining attention for low temperature heat transformation applications in thermally driven adsorption chillers (TDCs) or adsorption heat pumps (AHPs). TDCs or AHPs are an alternative to traditional air conditioners or heat pumps operating on electricity or fossil fuels. By using solar or waste heat as the operating energy TDCs or AHPs can significantly help to minimize primary energy consumption and greenhouse gas emissions generated by industrial or domestic heating and cooling processes. TDCs and AHPs are based on the evaporation and consecutive adsorption of coolant liquids, preferably water, under specific conditions. The process is driven and controlled by the microporosity and hydrophilicity of the employed sorption material. Here we summarize the current investigations, developments and possibilities of PCPs/MOFs for use in low-temperature heat transformation applications as alternative materials for the traditional inorganic porous substances like silica gel, aluminophosphates or zeolites.

  15. Protonation process of conjugated polyelectrolytes on enhanced power conversion efficiency in the inverted polymer solar cells

    NASA Astrophysics Data System (ADS)

    Yi, Chao; Hu, Rong; Ren, He; Hu, Xiaowen; Wang, Shu; Gong, Xiong; Cao, Yong

    2014-01-01

    In this study, two conjugated polyelectrolytes, polythiophene derivative (PTP) and poly[(9,9-bis [6‧-N, N, N-trimethylammonium] hexyl)-fluorenylene-phenylene] dibromide (PFP), are utilized to modify the surface properties of ZnO electron extraction layer (EEL) in the inverted polymer solar cells (PSCs). Both higher short-circuit current densities and larger open-circuit voltages were observed from the inverted PSCs with ZnO/PFP or ZnO/PTP as compared with those only with ZnO EEL. The protonation process for PTP and PFP in solution is distinguished. Overall, more than 40% enhanced power conversion efficiency (PCE) from the inverted PSCs with ZnO/PFP, in which the PFP could be fully ionized in deionized water, and more than 30% enhanced PCE from the inverted PSCs with ZnO/PTP, as the case that the PTP could not be fully ionized in deionized water, as compared with the inverted PSCs with ZnO EEL were observed, respectively. These results demonstrate that the conjugated polyelectrolytes play an important role in enhancement of device performance of inverted PSCs and that the protonation process of the conjugated polyelectrolytes is critical to the modification for EEL in PSCs.

  16. Porous coordination polymers as novel sorption materials for heat transformation processes.

    PubMed

    Janiak, Christoph; Henninger, Stefan K

    2013-01-01

    Porous coordination polymers (PCPs)/metal-organic frameworks (MOFs) are inorganic-organic hybrid materials with a permanent three-dimensional porous metal-ligand network. PCPs or MOFs are inorganic-organic analogs of zeolites in terms of porosity and reversible guest exchange properties. Microporous water-stable PCPs with high water uptake capacity are gaining attention for low temperature heat transformation applications in thermally driven adsorption chillers (TDCs) or adsorption heat pumps (AHPs). TDCs or AHPs are an alternative to traditional air conditioners or heat pumps operating on electricity or fossil fuels. By using solar or waste heat as the operating energy TDCs or AHPs can significantly help to minimize primary energy consumption and greenhouse gas emissions generated by industrial or domestic heating and cooling processes. TDCs and AHPs are based on the evaporation and consecutive adsorption of coolant liquids, preferably water, under specific conditions. The process is driven and controlled by the microporosity and hydrophilicity of the employed sorption material. Here we summarize the current investigations, developments and possibilities of PCPs/MOFs for use in low-temperature heat transformation applications as alternative materials for the traditional inorganic porous substances like silica gel, aluminophosphates or zeolites. PMID:23945102

  17. USING THE SULFUR POLYMER STABILIZATION SOLIDIFICATION PROCESS TO TREAT RESIDUAL MERCURY WASTES FROM GOLD MINING OPERATIONS.

    SciTech Connect

    BOWERMAN,B.ADAMS,J.KALB,P.WAN,R.Y.LEVIER,M.

    2003-02-24

    Large quantities of mercury are generated as a by-product during the processing of gold ore following mining operations. Newmont Mining Corporation (NMC), which operates some of the world's largest gold mines, sought a method to permanently ''retire'' its mercury by-products, thereby avoiding potential environmental liability. Sulfur Polymer Stabilization-Solidification (SPSS) is an innovative technology developed at Brookhaven National Laboratory (BNL) for treatment of mercury and mercury contaminated materials, such as soil, sludge and debris. BNL conducted a treatability study to determine the potential applicability of SPSS for treatment of Newmont mercury, and the treated product passed the U.S. Environmental Protection Agency (EPA) test for toxicity. The SPSS process has been shown to be effective on radioactive and nonradioactive mercury and mercury-contaminated materials with a pilot-scale batch system capable of producing 0.03 m{sup 3} (1 ft{sup 3}) per batch. Engineering scale-up issues are discussed and material property tests addressing these issues are described.

  18. Gas expanded polymer process to anneal nanoparticle dispersion in thin films

    DOE PAGES

    Ambuken, Preejith V.; Stretz, Holly A.; Dadmun, Mark; Michael Kilbey, S.

    2015-04-21

    A spin-coating solution comprising poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) nanoparticles used to create organic photovoltaic (OPV) active layers have been shown to adopt a non-uniform concentration profile across the thin film dimension. This inhomogeneous distribution can reduce the efficiency of the device. For our new process, gas expanded polymer (GXP) annealing, is applied to P3HT/PCBM thin film blends, enabling the distribution of the PCBM nanoparticles to be manipulated by varying the GXP processing conditions. Films of 50 nm thickness (nominally) created by spin casting a blend of P3HT mixed with PCBM were annealed by oscillatory GXP andmore » GXP at constant pressure using high pressure CO2. An increase in P3HT crystallinity (detected by X-ray diffraction and UV-vis spectroscopy) along with a more uniform distribution of PCBM nanoparticles in the thickness dimension, as interpreted from neutron reflectivity measurements, were observed after oscillatory GXP annealing. In addition, static water contact angles suggest that the film/air interface is enriched in PCBM relative to the as-cast film. Finally, these results demonstrate that GXP annealing, which is commercially scalable, can be successfully used to create a uniform distribution of PCBM nanoparticles across the thickness dimension in a P3HT thin film.« less

  19. Gas expanded polymer process to anneal nanoparticle dispersion in thin films

    SciTech Connect

    Ambuken, Preejith V.; Stretz, Holly A.; Dadmun, Mark; Michael Kilbey, S.

    2015-04-21

    A spin-coating solution comprising poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) nanoparticles used to create organic photovoltaic (OPV) active layers have been shown to adopt a non-uniform concentration profile across the thin film dimension. This inhomogeneous distribution can reduce the efficiency of the device. For our new process, gas expanded polymer (GXP) annealing, is applied to P3HT/PCBM thin film blends, enabling the distribution of the PCBM nanoparticles to be manipulated by varying the GXP processing conditions. Films of 50 nm thickness (nominally) created by spin casting a blend of P3HT mixed with PCBM were annealed by oscillatory GXP and GXP at constant pressure using high pressure CO2. An increase in P3HT crystallinity (detected by X-ray diffraction and UV-vis spectroscopy) along with a more uniform distribution of PCBM nanoparticles in the thickness dimension, as interpreted from neutron reflectivity measurements, were observed after oscillatory GXP annealing. In addition, static water contact angles suggest that the film/air interface is enriched in PCBM relative to the as-cast film. Finally, these results demonstrate that GXP annealing, which is commercially scalable, can be successfully used to create a uniform distribution of PCBM nanoparticles across the thickness dimension in a P3HT thin film.

  20. Recycling and processing of several typical crosslinked polymer scraps with enhanced mechanical properties based on solid-state mechanochemical milling

    NASA Astrophysics Data System (ADS)

    Lu, Canhui; Zhang, Xinxing; Zhang, Wei

    2015-05-01

    The partially devulcanization or de-crosslinking of ground tire rubber (GTR), post-vulcanized fluororubber scraps and crosslinked polyethylene from cable scraps through high-shear mechanochemical milling (HSMM) was conducted by a modified solid-state mechanochemical reactor. The results indicated that the HSMM treated crosslinked polymer scraps can be reprocessed as virgin rubbers or thermoplastics to produce materials with high performance. The foamed composites of low density polyethylene/GTR and the blend of post-vulcanized flurorubber (FKM) with polyacrylate rubber (ACM) with better processability and mechanical properties were obtained. The morphology observation showed that the dispersion and compatibility between de-crosslinked polymer scraps and matrix were enhanced. The results demonstrated that HSMM is a feasible alternative technology for recycling post-vulcanized or crosslinked polymer scraps.

  1. Recycling and processing of several typical crosslinked polymer scraps with enhanced mechanical properties based on solid-state mechanochemical milling

    SciTech Connect

    Lu, Canhui; Zhang, Xinxing; Zhang, Wei

    2015-05-22

    The partially devulcanization or de-crosslinking of ground tire rubber (GTR), post-vulcanized fluororubber scraps and crosslinked polyethylene from cable scraps through high-shear mechanochemical milling (HSMM) was conducted by a modified solid-state mechanochemical reactor. The results indicated that the HSMM treated crosslinked polymer scraps can be reprocessed as virgin rubbers or thermoplastics to produce materials with high performance. The foamed composites of low density polyethylene/GTR and the blend of post-vulcanized flurorubber (FKM) with polyacrylate rubber (ACM) with better processability and mechanical properties were obtained. The morphology observation showed that the dispersion and compatibility between de-crosslinked polymer scraps and matrix were enhanced. The results demonstrated that HSMM is a feasible alternative technology for recycling post-vulcanized or crosslinked polymer scraps.

  2. Photothermal triggering of self-healing processes applied to the reparation of bio-based polymer networks

    NASA Astrophysics Data System (ADS)

    Altuna, F. I.; Antonacci, J.; Arenas, G. F.; Pettarin, V.; Hoppe, C. E.; Williams, R. J. J.

    2016-04-01

    Green laser irradiation successfully activated self-healing processes in epoxy-acid networks modified with low amounts of gold nanoparticles (NPs). A bio-based polymer matrix, obtained by crosslinking epoxidized soybean oil (ESO) with an aqueous citric acid (CA) solution, was self-healed through molecular rearrangements produced by transesterification reactions of β-hydroxyester groups generated in the polymerization reaction. The temperature increase required for the triggering of these thermally activated reactions was attained by green light irradiation of the damaged area. Compression force needed to assure a good contact between crack faces was achieved by volume dilatation generated by the same temperature rise. Gold NPs dispersed in the polymer efficiently generated heat in the presence of electromagnetic radiation under plasmon resonance, acting as nanometric heating sources and allowing remote activation of the self-healing in the crosslinked polymer.

  3. Rapid and effective decontamination of chlorophenol-contaminated soil by sorption into commercial polymers: concept demonstration and process modeling.

    PubMed

    Tomei, M Concetta; Mosca Angelucci, Domenica; Ademollo, Nicoletta; Daugulis, Andrew J

    2015-03-01

    Solid phase extraction performed with commercial polymer beads to treat soil contaminated by chlorophenols (4-chlorophenol, 2,4-dichlorophenol and pentachlorophenol) as single compounds and in a mixture has been investigated in this study. Soil-water-polymer partition tests were conducted to determine the relative affinities of single compounds in soil-water and polymer-water pairs. Subsequent soil extraction tests were performed with Hytrel 8206, the polymer showing the highest affinity for the tested chlorophenols. Factors that were examined were polymer type, moisture content, and contamination level. Increased moisture content (up to 100%) improved the extraction efficiency for all three compounds. Extraction tests at this upper level of moisture content showed removal efficiencies ≥70% for all the compounds and their ternary mixture, for 24 h of contact time, which is in contrast to the weeks and months, normally required for conventional ex situ remediation processes. A dynamic model characterizing the rate and extent of decontamination was also formulated, calibrated and validated with the experimental data. The proposed model, based on the simplified approach of "lumped parameters" for the mass transfer coefficients, provided very good predictions of the experimental data for the absorptive removal of contaminants from soil at different individual solute levels. Parameters evaluated from calibration by fitting of single compound data, have been successfully applied to predict mixture data, with differences between experimental and predicted data in all cases being ≤3%.

  4. FOR STIMULI-RESPONSIVE POLYMERS WITH ENHANCED EFFICIENCY IN RESERVOIR RECOVERY PROCESSES

    SciTech Connect

    Charles McCormick; Roger Hester

    2002-04-29

    To date, our synthetic research efforts have been focused on the development of stimuli-responsive water-soluble polymers designed for use in enhanced oil recovery (EOR) applications. These model systems are structurally tailored for potential application as viscosifiers and/or mobility control agents for secondary and tertiary EOR methods. The following report discloses the progress of our ongoing research of polyzwitterions, polymers derived from monomers bearing both positive and negative charges, that show the ability to sustain or increase their hydrodynamic volume (and thus, solution viscosity) in the presence of electrolytes. Such polymers appear to be well-suited for use under conditions similar to those encountered in EOR operations. Additionally, we disclose the synthesis and characterization of a well-defined set of polyacrylamide (PAM) homopolymers that vary by MW. The MW of the PAM samples is controlled by addition of sodium formate to the polymerization medium as a conventional chain transfer agent. Data derived from polymer characterization is used to determine the kinetic parameter C{sub CT}, the chain transfer constant to sodium formate under the given polymerization conditions. The PAM homopolymer series will be employed in future set of experiments designed to test a simplified intrinsic viscosity equation. The flow resistance of a polymer solution through a porous medium is controlled by the polymer's hydrodynamic volume, which is strongly related to it's intrinsic viscosity. However, the hydrodynamic volume of a polymer molecule in an aqueous solution varies with fluid temperature, solvent composition, and polymer structure. This report on the theory of polymer solubility accentuates the importance of developing polymer solutions that increase in intrinsic viscosity when fluid temperatures are elevated above room conditions. The intrinsic viscosity response to temperature and molecular weight variations of three polymer solutions verified the

  5. Air-processable silane-coupled polymers to modify a dielectric for solution-processed organic semiconductors.

    PubMed

    Jang, Mi; Yu, Young Chang; Jeon, Hyeonyeol; Youk, Ji Ho; Yang, Hoichang

    2015-03-11

    Poly(styrene-r-3-methacryloxypropyltrimethoxysilane) (PSMPTS) copolymers were synthesized by the free radical polymerization of styrene and 3-methacryloxypropyltrimethoxysilane (MPTS) for use as surface modifiers. PSMPTS copolymers were spun-cast onto a hydrophilic SiO2 layer and were then annealed at 150 °C in ambient air. The polystyrene (PS)-based copolymer, with a molecular weight of 32 700 g mol(-1) and approximately 30 MPTS coupling sites, was easily grafted onto the SiO2 surface after annealing periods longer than 1 min, yielding a physicochemically stable layer. On the untreated and polymer-treated dielectrics, spin-casting of an ultrasonicated poly(3-hexyl thiophene) (P3HT) solution yielded highly interconnected crystal nanofibrils of P3HT. The resulting organic field-effect transistors (OFETs) showed similar mobility values of 0.01-0.012 cm(2) V(-1) s(-1) for all surfaces. However, the threshold voltage (Vth) drastically decreased from +13 (for bare SiO2) to 0 V by grafting the PSMPTS copolymers to the SiO2 surface. In particular, the interfacial charge traps that affect Vth were minimized by grafting the 11 mol % MPTS-loaded copolymer to the polar dielectric surface. We believe that this ambient-air-processable silane-coupled copolymer can be used as a solution-based surface modifier for continuous, large-scale OFET fabrication. PMID:25700018

  6. Air-processable silane-coupled polymers to modify a dielectric for solution-processed organic semiconductors.

    PubMed

    Jang, Mi; Yu, Young Chang; Jeon, Hyeonyeol; Youk, Ji Ho; Yang, Hoichang

    2015-03-11

    Poly(styrene-r-3-methacryloxypropyltrimethoxysilane) (PSMPTS) copolymers were synthesized by the free radical polymerization of styrene and 3-methacryloxypropyltrimethoxysilane (MPTS) for use as surface modifiers. PSMPTS copolymers were spun-cast onto a hydrophilic SiO2 layer and were then annealed at 150 °C in ambient air. The polystyrene (PS)-based copolymer, with a molecular weight of 32 700 g mol(-1) and approximately 30 MPTS coupling sites, was easily grafted onto the SiO2 surface after annealing periods longer than 1 min, yielding a physicochemically stable layer. On the untreated and polymer-treated dielectrics, spin-casting of an ultrasonicated poly(3-hexyl thiophene) (P3HT) solution yielded highly interconnected crystal nanofibrils of P3HT. The resulting organic field-effect transistors (OFETs) showed similar mobility values of 0.01-0.012 cm(2) V(-1) s(-1) for all surfaces. However, the threshold voltage (Vth) drastically decreased from +13 (for bare SiO2) to 0 V by grafting the PSMPTS copolymers to the SiO2 surface. In particular, the interfacial charge traps that affect Vth were minimized by grafting the 11 mol % MPTS-loaded copolymer to the polar dielectric surface. We believe that this ambient-air-processable silane-coupled copolymer can be used as a solution-based surface modifier for continuous, large-scale OFET fabrication.

  7. A process to recover carbon fibers from polymer-matrix composites in end-of-life vehicles

    NASA Astrophysics Data System (ADS)

    Jody, Bassam J.; Pomykala, Joseph A.; Daniels, Edward J.; Greminger, Jessica L.

    2004-08-01

    Because of their high strength-to-weight ratios, carbon-fiber-reinforced polymer-matrix composite (PMC) materials are being evaluated for use in the automotive industry. The major barriers to their widespread use are their relatively high cost and the uncertainty about whether they can be recycled. A process to recover carbon fibers from obsolete PMC materials has been developed at Argonne National Laboratory. The process was tested using PMC samples made with different thermoset or thermoplastic substrates. For most mixtures of PMCs, the process can be energy self-sufficient using the polymer substrate as an energy source. An evaluation of the recovered samples found that the fibers appear to have retained good properties and characteristics and are suitable for short fiber applications. This paper describes the process and the characteristics and properties of the recovered fibers.

  8. Modeling & processing of ceramic and polymer precursor ceramic matrix composite materials

    NASA Astrophysics Data System (ADS)

    Wang, Xiaolin

    of filler particle reaction, microstructure evolution, at the microscale as well as transient fluid flow, heat transfer, and species transport at the macroscale. The model comprises of (i) a microscale model and (ii) a macroscale transport model, and aims to provide optimal conditions for the fabrication process of the ceramics. The porous media macroscale model for SiC-based metal-ceramic materials processing will be developed to understand the thermal polymer pyrolysis, chemical reaction of active fillers and transport phenomena in the porous media. The macroscale model will include heat and mass transfer, curing, pyrolysis, chemical reaction and crystallization in a mixture of preceramic polymers and submicron/nano-sized metal particles of uranium, zirconium, niobium, or hafnium. The effects of heating rate, sample size, size and volume ratio of the metal particles on the reaction rate and product uniformity will be studied. The microscale model will be developed for modeling the synthesis of SiC matrix and metal particles. The macroscale model provides thermal boundary conditions to the microscale model. The microscale model applies to repetitive units in the porous structure and describes mass transport, composition changes and motion of metal particles. The unit-cell is the representation unit of the source material, and it consists of several metal particles, SiC matrix and other components produced from the synthesis process. The reactions between different components, the microstructure evolution of the product will be considered. The effects of heating rate and metal particle size on species uniformity and microstructure are investigated.

  9. For Stimul-Responsive Polymers with Enhanced Efficiency in Reservoir Recovery Processes

    SciTech Connect

    Charles McCormick; Roger Hester

    2003-02-28

    Acrylamide-based hydrophobically modified (HM) polybetaines containing N-butylphenylacrylamide (BPAM) and varying amounts of either sulfobetaine (3-(2-acrylamido-2-methylpropanedimethylammonio)-1-propanesulfonate, AMPDAPS) or carboxybetaine (4-(2-acrylamido-2-methylpropyldimethylammonio) butanoate, AMPDAB) comonomers were synthesized via micellar copolymerization. The terpolymers were characterized via {sup 13}C NMR and UV spectroscopies, classical and dynamic light scattering, and potentiometric titration. The response of aqueous polymer solutions to various external stimuli, including changes in solution pH, electrolyte concentration, and the addition of small molecule surfactants, was investigated using surface tension and rheological measurements. Low charge density terpolymers were found to show greater viscosity enhancement upon the addition of surfactant compared to the high charge density terpolymers. The addition of sodium dodecyl sulfate (SDS) produced the largest maximum in solution viscosity, while N-dodecyl-N,N,N-trimethylammonium bromide (DTAB), N-dodecyl-N,N-dimethylammonio-1-propanesulfonate (SB3-12), and Triton X-100 tended to show reduced viscosity enhancement. In most cases, the high charge density carboxybetaine terpolymer exhibited diminished solution viscosities upon surfactant addition. In our last report, we discussed solution thermodynamic theory that described changes in polymer coil conformation as a function of solution temperature and polymer molecular weight. These polymers contained no ionic charges. In this report, we expand polymer solution theory to account for the electrostatic interactions present in solutions of charged polymers. Polymers with ionic charges are referred to as polyions or polyelectrolytes.

  10. Efficient inverted polymer solar cells using low-temperature zinc oxide interlayer processed from aqueous solution

    NASA Astrophysics Data System (ADS)

    Chen, Dazheng; Zhang, Chunfu; Heng, Ting; Wei, Wei; Wang, Zhizhe; Han, Genquan; Feng, Qian; Hao, Yue; Zhang, Jincheng

    2015-04-01

    In this work, an aqueous solution method that entails processing at low temperatures is utilized to deposit a ZnO interlayer in poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl C61 butyric acid methyl ester-based inverted polymer solar cells (PSCs). The effect of ZnO annealing temperature from 50 to 150 °C on PSC performance is systemically studied and it is found that the transition point is approximately 80 °C. When the ZnO annealing temperature is higher than 80 °C, PSCs show similar current density-voltage (J-V) characteristics and achieve a power conversion efficiency higher than 3.5%. Transmittance spectrum, PL spectrum, and surface morphology studies show that an annealing temperature above 80 °C is sufficient for ZnO to achieve a relatively good quality, and that a higher temperature only slightly improves ZnO quality, which is confirmed from statistical results. Furthermore, flexible PSCs based on PET substrates show a comparable power conversion efficiency and good flexibility.

  11. Solution-processed nickel compound as hole collection layer for efficient polymer solar cells

    NASA Astrophysics Data System (ADS)

    He, Shaojian; Li, Shusheng; Tan, Zhan'ao; Zheng, Hua; Lin, Jun; Hu, Siqian; Liu, Jiyan; Li, Yongfang

    2014-12-01

    We demonstrated efficient bulk heterojunction polymer solar cells (PSCs) by inserting a solution-processable hole collection layer (HCL) between the indium tin oxide (ITO) electrode and photoactive layer. The HCL was prepared by spin-coating nickel acetylacetonate (Ni(acac)2) isopropanol solution on ITO, and then baking in air at 180 °C for 10 min followed by UV ozone treatment, which was marked as a-Ni(acac)2. The a-Ni(acac)2 HCL shows suitable energy levels, high hole mobility of 4.09  ×  10-3 cm2 V-1·s-1, and high transparency with light transmittance better than poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) in the wavelength range 550-800 nm. The PSCs with a-Ni(acac)2 HCL showed improved performance compared with the PSCs without or with traditional PEDOT:PSS HCL. The power conversion efficiency of the PSC based on PBDTTT-C-T:PC70BM with a-Ni(acac)2 HCL reached 7.84% under the illumination of AM 1.5 G, 100 mW cm-2.

  12. Influence of Processing Conditions and Material Properties on Electrohydrodynamic Direct Patterning of a Polymer Solution

    NASA Astrophysics Data System (ADS)

    Jang, Shin; Kim, Yeongjun; Oh, Je Hoon

    2016-04-01

    An electrohydrodynamic (EHD) patterning method was utilized to obtain high-resolution line patterns in a low electric field regime without an additional mechanical drawing process. Molecular weight and weight percent of a polymer were selected as key parameters to reduce the voltage. EHD patterning was performed using polyethylene oxide (PEO) solutions. The threshold voltages (V th) to initiate jet ejection are almost the same for all solutions. A method verified in this study, reducing the driving voltage (V d) just after the initiation of the jet at the threshold voltage, can make a very thin, continuous jet, while increasing molecular weight and weight percent were enabled to further reduce the input voltage. As the voltage reduction ratio (V d/ V th) is decreased, the jet behaves like a solid rather than a liquid due to its fast solidification. The line width of the resultant line pattern could be tuned from 50 nm to 10 μm depending on the substrate moving speed. Contour maps were also developed that show the pattern mode variation as a function of the voltage reduction ratio and key parameters. The results show that well-defined PEO line and grid patterns can be fabricated via the proposed EHD direct patterning under appropriate conditions.

  13. The future of carbon dioxide for polymer processing in tissue engineering.

    PubMed

    Bhamidipati, Manjari; Scurto, Aaron M; Detamore, Michael S

    2013-06-01

    The use of CO2 for scaffold fabrication in tissue engineering was popularized in the mid-1990 s as a tool for producing polymeric foam scaffolds, but had fallen out of favor to some extent, in part due to challenges with pore interconnectivity. Pore interconnectivity issues have since been resolved by numerous dedicated studies that have collectively outlined how to control the appropriate parameters to achieve a pore structure desirable for tissue regeneration. In addition to CO2 foaming, several groups have leveraged CO2 as a swelling agent to impregnate scaffolds with drugs and other bioactive additives, and for encapsulation of plasmids within scaffolds for gene delivery. Moreover, in contrast to CO2 foaming, which typically relies on supercritical CO2 at very high pressures, CO2 at much lower pressures has also been used to sinter polymeric microspheres together in the presence of cells to create cell-seeded scaffolds in a single step. CO2 has a number of advantages for polymer processing in tissue engineering, including its ease of use, low cost, and the opportunity to circumvent the use of organic solvents. Building on these advantages, and especially now with the tremendous precedent that has paved the way in defining operating parameters, and making the technology accessible for new groups to adapt, we invite and encourage our colleagues in the field to leverage CO2 as a new tool to enhance their own respective unique capabilities.

  14. The Future of Carbon Dioxide for Polymer Processing in Tissue Engineering

    PubMed Central

    Bhamidipati, Manjari; Scurto, Aaron M.

    2013-01-01

    The use of CO2 for scaffold fabrication in tissue engineering was popularized in the mid-1990s as a tool for producing polymeric foam scaffolds, but had fallen out of favor to some extent, in part due to challenges with pore interconnectivity. Pore interconnectivity issues have since been resolved by numerous dedicated studies that have collectively outlined how to control the appropriate parameters to achieve a pore structure desirable for tissue regeneration. In addition to CO2 foaming, several groups have leveraged CO2 as a swelling agent to impregnate scaffolds with drugs and other bioactive additives, and for encapsulation of plasmids within scaffolds for gene delivery. Moreover, in contrast to CO2 foaming, which typically relies on supercritical CO2 at very high pressures, CO2 at much lower pressures has also been used to sinter polymeric microspheres together in the presence of cells to create cell-seeded scaffolds in a single step. CO2 has a number of advantages for polymer processing in tissue engineering, including its ease of use, low cost, and the opportunity to circumvent the use of organic solvents. Building on these advantages, and especially now with the tremendous precedent that has paved the way in defining operating parameters, and making the technology accessible for new groups to adapt, we invite and encourage our colleagues in the field to leverage CO2 as a new tool to enhance their own respective unique capabilities. PMID:23289736

  15. The effect of processing additives for charge generation, recombination, and extraction in bulk heterojunction layers of all-polymer photovoltaics

    NASA Astrophysics Data System (ADS)

    Kim, Yu Jin; Ahn, Sunyong; Wang, Dong Hwan; Park, Chan Eon

    2015-08-01

    Bulk heterojunction all-polymer solar cells, fabricated with poly{[4,8-bis-(2-ethyl-hexyl-thiophene-5-yl)-benzo[1,2-b:4,5-b']dithiophene-2,6-diyl]-alt-[2-(2-ethyl-hexanoyl)-thieno[3,4-b']thiophen-4,6-diyl]} (PBDTTT-CT) as a donor polymer, and a acceptor polymer, poly{[N,N'-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)} (P(NDI2OD-T2)), have been demonstrated and have achieved a power conversion efficiency exceeding 3.7% by using 1,8-diiodooctane (DIO) as a processing additive. Based on the analysis of charge carrier dynamics (charge generation, separation, and extraction), we found that the appropriate ratio of processing solvent additive (5 vol. % DIO) leads to enhanced device performance and favorable morphological characteristics. This research, therefore, indicates that the incorporation of a DIO additive in all-polymer blends is an effective way to form a morphologically ideal heterojunction network and thereby improve charge carrier kinetics for efficient photovoltaic devices.

  16. CO2-assisted high pressure homogenization: a solvent-free process for polymeric microspheres and drug-polymer composites.

    PubMed

    Kluge, Johannes; Mazzotti, Marco

    2012-10-15

    The study explores the enabling role of near-critical CO(2) as a reversible plasticizer in the high pressure homogenization of polymer particles, aiming at their comminution as well as at the formation of drug-polymer composites. First, the effect of near-critical CO(2) on the homogenization of aqueous suspensions of poly lactic-co-glycolic acid (PLGA) was investigated. Applying a pressure drop of 900 bar and up to 150 passes across the homogenizer, it was found that particles processed in the presence of CO(2) were generally of microspherical morphology and at all times significantly smaller than those obtained in the absence of a plasticizer. The smallest particles, exhibiting a median x(50) of 1.3 μm, were obtained by adding a small quantity of ethyl acetate, which exerts on PLGA an additional plasticizing effect during the homogenization step. Further, the study concerns the possibility of forming drug-polymer composites through simultaneous high pressure homogenization of the two relevant solids, and particularly the effect of near-critical CO(2) on this process. Therefore, PLGA was homogenized together with crystalline S-ketoprofen (S-KET), a non-steroidal anti-inflammatory drug, at a drug to polymer ratio of 1:10, a pressure drop of 900 bar and up to 150 passes across the homogenizer. When the process was carried out in the presence of CO(2), an impregnation efficiency of 91% has been reached, corresponding to 8.3 wt.% of S-KET in PLGA; moreover, composite particles were of microspherical morphology and significantly smaller than those obtained in the absence of CO(2). The formation of drug-polymer composites through simultaneous homogenization of the two materials is thus greatly enhanced by the presence of CO(2), which increases the efficiency for both homogenization and impregnation.

  17. Electrodeposition of nonconducting polymers: roles of carbon nanotubes in the process and products.

    PubMed

    Hu, Di; Peng, Chuang; Chen, George Z

    2010-07-27

    The self-limiting electrodeposition of nonconducting polymers, such as poly(o-aminophenol) (PoAP), has been continued by the addition of acid treated carbon nanotubes (CNTs) into the aqueous monomer solution without any other supporting electrolyte. Electron microscopy revealed fairly thick (>8 microm) and highly porous nanocomposite films on electrodes, consisting of CNTs which were well interconnected and individually coated with a thin layer (e.g., 30 nm) of the nonconducting polymer. The mechanism behind this approach is explainable by the newly arrived CNTs and those entrapped in the nonconducting polymer matrix providing extra reaction and growth sites, and extended electron pathways, leading to sustained electro-co-deposition of the nonconducting polymer and CNTs into the nanoporous composite films. Promising applications of the PoAP-CNT composite were explored, such as CO2 sensing in water, and energy storage in an unprecedented metal-free supercapattery. PMID:20550142

  18. Polyhydroxyalkanoates production with mixed microbial cultures: from culture selection to polymer recovery in a high-rate continuous process.

    PubMed

    Villano, Marianna; Valentino, Francesco; Barbetta, Andrea; Martino, Lucrezia; Scandola, Mariastella; Majone, Mauro

    2014-06-25

    Polyhydroxyalkanoates (PHA) production with mixed microbial cultures (MMC) has been investigated by means of a sequential process involving three different stages, consisting of a lab-scale sequencing batch reactor for MMC selection, a PHA accumulation reactor and a polymer extraction reactor. All stages were performed under continuous operation for at least 4 months to check the overall process robustness as well as the related variability of polymer composition and properties. By operating both biological stages at high organic loads (8.5 and 29.1 gCOD/Ld, respectively) with a synthetic mixture of acetic and propionic acid, it was possible to continuously produce PHA at 1.43 g/Ld with stable performance (overall, the storage yield was 0.18 COD/COD). To identify the optimal operating conditions of the extraction reactor, two digestion solutions have been tested, NaOH (1m) and NaClO (5% active Cl2). The latter resulted in the best performance both in terms of yield of polymer recovery (around 100%, w/w) and purity (more than 90% of PHA content in the residual solids, on a weight basis). In spite of the stable operating conditions and performance, a large variation was observed for the HV content, ranging between 4 and 20 (%, w/w) for daily samples after accumulation and between 9 and 13 (%, w/w) for weekly average samples after extraction and lyophilization. The molecular weight of the produced polymer ranged between 3.4 × 10(5) and 5.4 × 10(5)g/mol with a large polydispersity index. By contrast, TGA and DSC analysis showed that the thermal polymer behavior did not substantially change over time, although it was strongly affected by the extraction agent used (NaClO or NaOH).

  19. Improved electron transport properties of n-type naphthalenediimide polymers through refined molecular ordering and orientation induced by processing solvents.

    PubMed

    An, Yujin; Long, Dang Xuan; Kim, Yiho; Noh, Yong-Young; Yang, Changduk

    2016-05-14

    To determine the role played by the choice of processing solvents in governing the photophysics, microstructure, and charge carrier transport in naphthalenediimide (NDI)-based polymers, we have prepared two new NDI-bithiophene (T2)- and NDI-thienothiophene (TTh)-containing polymers with hybrid siloxane pentyl chains (SiC5) (P(NDI2SiC5-T2) and P(NDI2SiC5-TTh)). Among the various processing solvents studied here, the films prepared using chloroform exhibited far better electron mobilities (0.16 ± 0.1-0.21 ± 0.05 cm(2) V(-1) s(-1)) than the corresponding samples prepared from different solvents, exceeding one order of magnitude higher, indicating the significant influence of the processing solvent on the charge transport. Upon thin-film analysis using atomic force microscopy and grazing incidence X-ray diffraction, we discovered that molecular ordering and orientation are affected by the choice of the processing solvent, which is responsible for the change in the transport characteristics of this class of polymers. PMID:27087486

  20. Electro-Mechanical Properties of Metal-Insulator-Metal Device Fabricated on Polymer Substrate Using Low-Temperature Process

    NASA Astrophysics Data System (ADS)

    Park, Sung Kyu; Han, Jeong In; Kim, Won Keun; Hong, Sung Jei; Kwak, Min Gi; Lee, Myung Jae; Chung, Kwan Soo

    2002-02-01

    High-performance metal-insulator-metal (MIM) devices on flexible polymer substrates were successfully fabricated without any defects such as cracks, delamination and blistering. This work examines the mechanical and electrical properties of MIM devices constructed using anodic Ta2O5 films. Using newly developed methods including stepped heating process and low-temperature post-annealing below 180°C, we obtained high-performances MIM devices on polymer substrates. Here, we propose the use of stacked bottom electrode and water barrier layer in order to enhance the ductility of the Ta electrode and to prevent blistering problems, respectively. Rutherford backscattering spectroscopy (RBS), auger electron spectroscopy (AES) and transmission electronic microscope (TEM) observations were performed for the structural investigation of the MIM devices on polymer substrates. Electrical measurements were also carried out for as-deposited and thermally treated MIM devices including Al/Ta/Ta2O5/Cr or Ti structures. They exhibit a low leakage current (below 10-7 A/cm2 at 2 MV) and reasonable breakdown voltage (5-7 MV/cm) with a uniformity of 92%. Finally, under low-temperature post-annealing conditions, The Current-Voltage (I-V) behaviors and conduction mechanisms of MIM devices on polymer substrates are discussed based on the results of electrical measurements, structural investigations and conduction band modeling.