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Sample records for organic plasma polymer

  1. Measurement of desorbed products during organic polymer thin film etching by plasma beam irradiation

    SciTech Connect

    Kurihara, Kazuaki; Karahashi, Kazuhiro; Egami, Akihiro; Nakamura, Moritaka

    2006-11-15

    The authors investigated the etching characteristics of three kinds of methacrylate polymer films, which have the same main chain but with different side chains, using a plasma beam irradiation apparatus. The polymers are polytbutylmethacrylate, polybenzylmethacrylate, and polycyclohexylmethacrylate. The major desorbed products during nitrogen plasma beam etching were found to be HCN and C{sub 2}N{sub 2} for all methacrylate polymer films. The desorbed products originating from the polymer structure, namely, the main chain and the side chain, were hardly observed. The energy distributions of desorbed products were mainly composed of Maxwell-Boltzmann distribution with a small component of collision cascade distribution for all three polymers and were slightly dependent on the ion energy. It is concluded that chemical sputtering, which can be defined as the production of weakly bound species by ion bombardment, followed by thermal desorption, is the significant ion induced mechanism of organic polymer etching.

  2. Plasma deposition of antimicrobial coating on organic polymer

    NASA Astrophysics Data System (ADS)

    Rżanek-Boroch, Zenobia; Dziadczyk, Paulina; Czajkowska, Danuta; Krawczyk, Krzysztof; Fabianowski, Wojciech

    2013-02-01

    Organic materials used for packing food products prevent the access of microorganisms or gases, like oxygen or water vapor. To prolong the stability of products, preservatives such as sulfur dioxide, sulfites, benzoates, nitrites and many other chemical compounds are used. To eliminate or limit the amount of preservatives added to food, so-called active packaging is sought for, which would limit the development of microorganisms. Such packaging can be achieved, among others, by plasma modification of a material to deposit on its surface substances inhibiting the growth of bacteria. In this work plasma modification was carried out in barrier discharge under atmospheric pressure. Sulfur dioxide or/and sodium oxide were used as the coating precursors. As a result of bacteriological studies it was found that sulfur containing coatings show a 16% inhibition of Salmonella bacteria growth and 8% inhibition of Staphylococcus aureus bacteria growth. Sodium containing coatings show worse (by 10%) inhibiting properties. Moreover, films with plasma deposited coatings show good sealing properties against water vapor. Contribution to the Topical Issue "13th International Symposium on High Pressure Low Temperature Plasma Chemistry (Hakone XIII)", Edited by Nicolas Gherardi, Henryca Danuta Stryczewska and Yvan Ségui.

  3. Study of organic polymer thin-film etching by plasma beam irradiation

    SciTech Connect

    Kurihara, Kazuaki; Egami, Akihiro; Nakamura, Moritaka

    2005-10-15

    We investigated the etching characteristics of three kinds of methacrylate polymer films which have the same main chain with a different side chain using a plasma beam irradiation apparatus. The polymers are polytbutylmethacrylate (PtBuMA), polybenzylmethacrylate (PBMA), and polycyclohexylmethacrylate (PCHMA). The etch yield (EY) of PtBuMA was higher than those of the others in the case of N{sub 2} plasma beam. The EYs of PBMA and PCHMA increased with an increase in the ion energy of up to 330 eV and saturated at over 330 eV. On the other hand, that of PtBuMA was almost constant at the ion energy higher than 130 eV. It was supposed that nitridation of the polymer plays an important role in the enhancement of etching by N{sub 2} plasma. In the case of Ar plasma, EY increased linearly with an increase in the square root of ion energy for every polymer. In the case of H{sub 2} plasmas, EY scarcely depended on the ion energy regardless of the polymers. Etching behaviors with Ar and H{sub 2} plasma irradiation showed physical sputtering and chemical sputtering, respectively. The order of the magnitude of EY was PtBuMA, PCHMA, and PBMA for all of the Ar, H{sub 2}, and N{sub 2} plasmas.

  4. Effects of Plasma Polymer Films and Their Deposition Powers on the Barrier Characteristics of the Multilayer Encapsulation for Organic Devices.

    PubMed

    Kim, Hoonbae; Ban, Wonjin; Kwon, Sungruel; Yong, Sanghyun; Chae, Heeyeop; Jung, Donggeun

    2016-05-01

    Organic electronic devices (OEDs) are quite suitable for use in flexible devices due to their ruggedness and flexibility. A number of researchers have studied the use of OEDs on flexible substrates in transparent, flexible devices in the near future. However, water and oxygen can permeate through the flexible substrates and can reduce the longevity of OEDs made from organic materials, which are weak to moisture and oxygen. In order to prevent the degradation of the OEDs, researchers have applied an encapsulation layer to the flexible substrates. In this study, Al2O3/plasma polymer film/Al2O3 multi-layers were deposited on polyethylene-naphthalate substrates through a combination of atomic layer deposition and plasma-enhanced chemical vapor deposition (PECVD). The plasma polymer film, which is located between the Al2O3 films, is deposited via PECVD with the use of a tetrakis(trimethylsilyloxy)silane precursor. The power of the plasma deposition varied from 10 to 50 W. The hydrophobicity of the plasma polymer film surfaces was investigated by measuring the water contact angle. The chemical structures of the plasma polymer films were measured via ex-situ Fourier transform infrared analysis. The permeation curves of the various films were analyzed by performing a calcium (Ca)-test. PMID:27483936

  5. Influence of molecular structure on the laser-induced plasma emission of the explosive RDX and organic polymers.

    PubMed

    De Lucia, Frank C; Gottfried, Jennifer L

    2013-10-01

    A series of organic polymers and the military explosive cyclotrimethylenetrinitramine (RDX) were studied using the light emission from a femtosecond laser-induced plasma under an argon atmosphere. The relationship between the molecular structure and plasma emission was established by using the percentages of the atomic species (C, H, N, O) and bond types (C-C, C═C, C-N, and C≡N) in combination with the atomic/molecular emission intensities and decay rates. In contrast to previous studies of organic explosives in which C2 was primarily formed by recombination, for the organic materials in this study the percentage of C-C (and C═C) bonds was strongly correlated to the molecular C2 emission. Time-resolved emission spectra were collected to determine the lifetimes of the atomic and molecular species in the plasma. Observed differences in decay rates were attributed to the differences in both the molecular structure of the organic polymers or RDX and the chemical reactions that occur within the plasma. These differences could potentially be exploited to improve the discrimination of explosive residues on organic substrates with laser-induced breakdown spectroscopy.

  6. Plasma surface modification of polymers

    NASA Technical Reports Server (NTRS)

    Hirotsu, T.

    1980-01-01

    Thin plasma polymerization films are discussed from the viewpoint of simplicity in production stages. The application of selective, absorbent films and films used in selective permeability was tested. The types of surface modification of polymers discussed are: (1) plasma etching, (2) surface coating by plasma polymerized thin films, and (3) plasma activation surface graft polymerization.

  7. Layered plasma polymer composite membranes

    DOEpatents

    Babcock, W.C.

    1994-10-11

    Layered plasma polymer composite fluid separation membranes are disclosed, which comprise alternating selective and permeable layers for a total of at least 2n layers, where n is [>=]2 and is the number of selective layers. 2 figs.

  8. Distributed Pore Chemistry in Porous Organic Polymers

    NASA Technical Reports Server (NTRS)

    Koontz, Steven L. (Inventor)

    1998-01-01

    A method for making a biocompatible polymer article using a uniform atomic oxygen treatment is disclosed. The sub-strate may be subsequently optionally grated with a compatibilizing compound. Compatibilizing compounds may include proteins, phosphorylcholine groups, platelet adhesion preventing polymers, albumin adhesion promoters, and the like. The compatibilized substrate may also have a living cell layer adhered thereto. The atomic oxygen is preferably produced by a flowing afterglow microwave discharge, wherein the substrate resides in a sidearm out of the plasma. Also, methods for culturing cells for various purposes using the various membranes are disclosed as well. Also disclosed are porous organic polymers having a distributed pore chemistry (DPC) comprising hydrophilic and hydrophobic region, and a method for making the DPC by exposing the polymer to atomic oxygen wherein the rate of hydrophilization is greater than the rate of mass loss.

  9. Distributed Pore Chemistry in Porous Organic Polymers

    NASA Technical Reports Server (NTRS)

    Koontz, Steven L. (Inventor)

    1999-01-01

    A method for making a biocompatible polymer article using a uniform atomic oxygen treatment is disclosed. The substrate may be subsequently optionally grated with a compatibilizing compound. Compatibilizing compounds may include proteins, phosphorylcholine groups, platelet adhesion preventing polymers, albumin adhesion promoters, and the like. The compatibilized substrate may also have a living cell layer adhered thereto. The atomic oxygen is preferably produced by a flowing afterglow microwave discharge. wherein the substrate resides in a sidearm out of the plasma. Also, methods for culturing cells for various purposes using the various membranes are disclosed as well. Also disclosed are porous organic polymers having a distributed pore chemistry (DPC) comprising hydrophilic and hydrophobic regions. and a method for making the DPC by exposing the polymer to atomic oxygen wherein the rate of hydrophilization is greater than the rate of mass loss.

  10. Permselective, metal chelate containing, plasma polymers

    SciTech Connect

    Morosoff, N.C.; Clymer, S.D.; Stannett, V.T.; Skelly, J.M.; Crumbliss, A.L.

    1993-12-31

    Metal chelates, including cobalt Schiff bases and a cobalt porphyrin complex, have been codeposited with hydrocarbon plasma polymers to form thin films. The hydrocarbon monomers used were trans-2-butene and cyclooctene. The sorption of O{sub 2} by such membranes before and after reaction with pyridine (Pyr) or 1-methylimidazole (1-MeIm) was measured and the association FTIR and uv/visible absorption spectra were obtained. In addition permeability to O{sub 2} and N{sub 2} was determined. It was found that the structure of the metal chelates, which were sublimed into the plasma, was preserved. When bound to an axial base (Pyr or 1-MeIm), the plasma polymer occluded chelates bound O{sub 2} reversibly. O{sub 2} diffusion coefficients varied with the nature of the plasma polymer matrix. The ideal separation factor (O{sub 2}/N{sub 2}) increased for metal chelate containing plasma polymers vis-a-vis that for the plasma polymer matrix (without metal chelate). The ideal separation factor was at a maximum for low metal chelate loading and at a {open_quotes}mass thickness{close_quotes} of {approximately} 10 {mu}g/(cm{sup 2}min).

  11. Furfuryl methacrylate plasma polymers for biomedical applications.

    PubMed

    Shirazi, Hanieh Safizadeh; Rogers, Nicholas; Michelmore, Andrew; Whittle, Jason D

    2016-01-01

    Furfuryl methacrylate (FMA) is a promising precursor for producing polymers for biomedical and cell therapy applications. Herein, FMA plasma polymer coatings were prepared with different powers, deposition times, and flow rates. The plasma polymer coatings were characterized using atomic force microscopy (AFM), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The results from AFM and SEM show the early growth of the coatings and the existence of particle aggregates on the surfaces. XPS results indicated no measureable chemical differences between the deposited films produced under different power and flow rate conditions. ToF-SIMS analysis demonstrated differing amounts of C5H5O (81 m/z) and C10H9O2 (161 m/z) species in the coatings which are related to the furan ring structure. Through judicious choice of plasma polymerization parameters, the quantity of the particle aggregates was reduced, and the fabricated plasma polymer coatings were chemically uniform and smooth. Primary human fibroblasts were cultured on FMA plasma polymer surfaces to determine the effect of surface chemical composition and the presence of particle aggregates on cell culture. Particle aggregates were shown to inhibit fibroblast attachment and proliferation.

  12. Furfuryl methacrylate plasma polymers for biomedical applications.

    PubMed

    Shirazi, Hanieh Safizadeh; Rogers, Nicholas; Michelmore, Andrew; Whittle, Jason D

    2016-01-01

    Furfuryl methacrylate (FMA) is a promising precursor for producing polymers for biomedical and cell therapy applications. Herein, FMA plasma polymer coatings were prepared with different powers, deposition times, and flow rates. The plasma polymer coatings were characterized using atomic force microscopy (AFM), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The results from AFM and SEM show the early growth of the coatings and the existence of particle aggregates on the surfaces. XPS results indicated no measureable chemical differences between the deposited films produced under different power and flow rate conditions. ToF-SIMS analysis demonstrated differing amounts of C5H5O (81 m/z) and C10H9O2 (161 m/z) species in the coatings which are related to the furan ring structure. Through judicious choice of plasma polymerization parameters, the quantity of the particle aggregates was reduced, and the fabricated plasma polymer coatings were chemically uniform and smooth. Primary human fibroblasts were cultured on FMA plasma polymer surfaces to determine the effect of surface chemical composition and the presence of particle aggregates on cell culture. Particle aggregates were shown to inhibit fibroblast attachment and proliferation. PMID:27609095

  13. Plasma polymer films for surface modification

    NASA Astrophysics Data System (ADS)

    Biederman, Hynek; Hlidek, Pavel; Jezek, Jan; Slavinska, Danka; Zemek, Joseph

    1996-04-01

    Plasma polymers were deposited on various surfaces using Ar/n-hexane/water working gas mixture. In most cases a test surface consisting from glass substrate coated by plasma polymer of Ar/n-hexane was used. It has been found that wettability of this test surface improves with the increased water concentration in a working gas mixture or with the increased power to the discharge. The increased concentration of polar groups was observed by FTIR absorption in the films stored in humid environment. Rate of the water absorption in dependence on power used for the film deposition is discussed.

  14. Physical Organic Chemistry of Supramolecular Polymers

    PubMed Central

    Serpe, Michael J.; Craig, Stephen L.

    2008-01-01

    Unlike the case of traditional covalent polymers, the entanglements that determine properties of supramolecular polymers are defined by very specific, intermolecular interactions. Recent work using modular molecular platforms to probe the mechanisms underlying mechanical response of supramolecular polymers is reviewed. The contributions of supramolecular kinetics, thermodynamics, and conformational flexibility to supramolecular polymer properties in solutions of discrete polymers, in networks, and at interfaces, are described. Molecule-to-material relationships are established through methods reminiscent of classic physical organic chemistry. PMID:17279638

  15. Polymer Structure--Organic Aspects (Definitions).

    ERIC Educational Resources Information Center

    Carraher, Charles E., Jr.; Seymour, Raymond B.

    1988-01-01

    Lists alphabetically the definitions of key organic-based terms used in characterizing the structure of polymers. Includes several common polymers, some of their uses and their respective structures. (CW)

  16. Polymer surface modification by plasmas and photons

    NASA Astrophysics Data System (ADS)

    Chan, C.-M.; Ko, T.-M.; Hiraoka, H.

    1996-05-01

    Polymers have been applied successfully in fields such as adhesion, biomaterials, protective coatings, friction and wear, composites, microelectronic devices, and thin-film technology. In general, special surface properties with regard to chemical composition, hydrophilicity, roughness, crystallinity, conductivity, lubricity, and cross-linking density are required for the success of these applications. Polymers very often do not possess the surface properties needed for these applications. However, they have excellent bulk physical and chemical properties, are inexpensive, and are easy to process. For these reasons, surface modification techniques which can transform these inexpensive materials into highly valuable finished products have become an important part of the plastics and many other industries. In recent years, many advances have been made in developing surface treatments to alter the chemical and physical properties of polymer surfaces without affecting bulk properties. Common surface modification techniques include treatments by flame, corona, plasmas, photons, electron beams, ion beams, X-rays, and γ-rays. Plasma treatment is probably the most versatile surface treatment technique. Different types of gases such as argon, oxygen, nitrogen, fluorine, carbon dioxide, and water can produce the unique surface properties required by various applications. For example, oxygen-plasma treatment can increase the surface energy of polymers, whereas fluorine-plasma treatment can decrease the surface energy and improve the chemical inertness. Cross-linking at a polymer surface can be introduced by an inert-gas plasma. Modification by plasma treatment is usually confined to the top several hundred ångströms and does not affect the bulk properties. The main disadvantage of this technique is that it requires a vacuum system, which increases the cost of operation. Thin polymer films with unique chemical and physical properties are produced by plasma polymerization

  17. Megahertz organic/polymer diodes

    SciTech Connect

    Katz, Howard Edan; Sun, Jia; Pal, Nath Bhola

    2012-12-11

    Featured is an organic/polymer diode having a first layer composed essentially of one of an organic semiconductor material or a polymeric semiconductor material and a second layer formed on the first layer and being electrically coupled to the first layer such that current flows through the layers in one direction when a voltage is applied in one direction. The second layer is essentially composed of a material whose characteristics and properties are such that when formed on the first layer, the diode is capable of high frequency rectifications on the order of megahertz rectifications such as for example rectifications at one of above 100KHz, 500KhZ, IMHz, or 10 MHz. In further embodiments, the layers are arranged so as to be exposed to atmosphere.

  18. Recent developments in high temperature organic polymers

    NASA Technical Reports Server (NTRS)

    Hergenrother, P. M.

    1991-01-01

    Developments in high temperature organic polymers during the last 5 years with major emphasis on polyimides and poly(arylene ether)s are discussed. Specific polymers or series of polymers have been selected to demonstrate unique properties or the effect chemical structure has upon certain properties. This article is not intended to be a comprehensive review of high temperature polymer advancements during the last 5 years.

  19. Microbubble formation from plasma polymers.

    PubMed

    Shahravan, Anaram; Yelamarty, Srinath; Matsoukas, Themis

    2012-09-27

    We document the formation of liquid-like particles in a toluene glow discharge that subsequently solidify via a process that releases hydrogen to form a solid microbubble with micrometer-size diameter, nanometer-size shell thickness, and high volume fraction, in excess of 90%. Liquid-like particles are produced in a toluene plasma under conditions that promote low degree of cross-linking (low power, high pressure). When these are transferred for observation in TEM, they are seen to transform under irradiation by the electron beam into solid bubbles with diameter of about 3 μm. This transformation also takes place under laser irradiation of sufficient power and under heating. We present evidence that the formation of these microbubbles is due to solidification of the liquid-like precursor that is accompanied by release of hydrogen. This mechanism is supported by a geometric model that provides a quantitative description of the particle size before and after solidification. These unique stimuli-responsive particles exhibit the potential of using temperature, electron beam, or laser as a source to change their size and structure which may find application in thermal insulators, lightweight materials, and light scattering agents.

  20. Electrochemical Sensors Based on Organic Conjugated Polymers

    PubMed Central

    Rahman, Md. Aminur; Kumar, Pankaj; Park, Deog-Su; Shim, Yoon-Bo

    2008-01-01

    Organic conjugated polymers (conducting polymers) have emerged as potential candidates for electrochemical sensors. Due to their straightforward preparation methods, unique properties, and stability in air, conducting polymers have been applied to energy storage, electrochemical devices, memory devices, chemical sensors, and electrocatalysts. Conducting polymers are also known to be compatible with biological molecules in a neutral aqueous solution. Thus, these are extensively used in the fabrication of accurate, fast, and inexpensive devices, such as biosensors and chemical sensors in the medical diagnostic laboratories. Conducting polymer-based electrochemical sensors and biosensors play an important role in the improvement of public health and environment because rapid detection, high sensitivity, small size, and specificity are achievable for environmental monitoring and clinical diagnostics. In this review, we summarized the recent advances in conducting polymer-based electrochemical sensors, which covers chemical sensors (potentiometric, voltammetric, amperometric) and biosensors (enzyme based biosensors, immunosensors, DNA sensors).

  1. Cell-Culture Reactor Having a Porous Organic Polymer Membrane

    NASA Technical Reports Server (NTRS)

    Koontz, Steven L. (Inventor)

    2000-01-01

    A method for making a biocompatible polymer article using a uniform atomic oxygen treatment is disclosed. The substrate may be subsequently optionally grated with a compatibilizing compound. Compatibilizing compounds may include proteins, phosphory1choline groups, platelet adhesion preventing polymers, albumin adhesion promoters, and the like. The compatibilized substrate may also have a living cell layer adhered thereto. The atomic oxygen is preferably produced by a flowing afterglow microwave discharge, wherein the substrate resides in a sidearm out of the plasma. Also, methods for culturing cells for various purposes using the various membranes are disclosed as well. Also disclosed are porous organic polymers having a distributed pore chemistry (DPC) comprising hydrophilic and hydrophobic regions, and a method for making the DPC by exposing the polymer to atomic oxygen wherein the rate of hydrophilization is greater than the rate of mass loss.

  2. Diketopyrrolopyrrole Polymers for Organic Solar Cells.

    PubMed

    Li, Weiwei; Hendriks, Koen H; Wienk, Martijn M; Janssen, René A J

    2016-01-19

    Conjugated polymers have been extensively studied for application in organic solar cells. In designing new polymers, particular attention has been given to tuning the absorption spectrum, molecular energy levels, crystallinity, and charge carrier mobility to enhance performance. As a result, the power conversion efficiencies (PCEs) of solar cells based on conjugated polymers as electron donor and fullerene derivatives as electron acceptor have exceeded 10% in single-junction and 11% in multijunction devices. Despite these efforts, it is notoriously difficult to establish thorough structure-property relationships that will be required to further optimize existing high-performance polymers to their intrinsic limits. In this Account, we highlight progress on the development and our understanding of diketopyrrolopyrrole (DPP) based conjugated polymers for polymer solar cells. The DPP moiety is strongly electron withdrawing and its polar nature enhances the tendency of DPP-based polymers to crystallize. As a result, DPP-based conjugated polymers often exhibit an advantageously broad and tunable optical absorption, up to 1000 nm, and high mobilities for holes and electrons, which can result in high photocurrents and good fill factors in solar cells. Here we focus on the structural modifications applied to DPP polymers and rationalize and explain the relationships between chemical structure and organic photovoltaic performance. The DPP polymers can be tuned via their aromatic substituents, their alkyl side chains, and the nature of the π-conjugated segment linking the units along the polymer chain. We show that these building blocks work together in determining the molecular conformation, the optical properties, the charge carrier mobility, and the solubility of the polymer. We identify the latter as a decisive parameter for DPP-based organic solar cells because it regulates the diameter of the semicrystalline DPP polymer fibers that form in the photovoltaic blends with

  3. Diketopyrrolopyrrole Polymers for Organic Solar Cells.

    PubMed

    Li, Weiwei; Hendriks, Koen H; Wienk, Martijn M; Janssen, René A J

    2016-01-19

    Conjugated polymers have been extensively studied for application in organic solar cells. In designing new polymers, particular attention has been given to tuning the absorption spectrum, molecular energy levels, crystallinity, and charge carrier mobility to enhance performance. As a result, the power conversion efficiencies (PCEs) of solar cells based on conjugated polymers as electron donor and fullerene derivatives as electron acceptor have exceeded 10% in single-junction and 11% in multijunction devices. Despite these efforts, it is notoriously difficult to establish thorough structure-property relationships that will be required to further optimize existing high-performance polymers to their intrinsic limits. In this Account, we highlight progress on the development and our understanding of diketopyrrolopyrrole (DPP) based conjugated polymers for polymer solar cells. The DPP moiety is strongly electron withdrawing and its polar nature enhances the tendency of DPP-based polymers to crystallize. As a result, DPP-based conjugated polymers often exhibit an advantageously broad and tunable optical absorption, up to 1000 nm, and high mobilities for holes and electrons, which can result in high photocurrents and good fill factors in solar cells. Here we focus on the structural modifications applied to DPP polymers and rationalize and explain the relationships between chemical structure and organic photovoltaic performance. The DPP polymers can be tuned via their aromatic substituents, their alkyl side chains, and the nature of the π-conjugated segment linking the units along the polymer chain. We show that these building blocks work together in determining the molecular conformation, the optical properties, the charge carrier mobility, and the solubility of the polymer. We identify the latter as a decisive parameter for DPP-based organic solar cells because it regulates the diameter of the semicrystalline DPP polymer fibers that form in the photovoltaic blends with

  4. Nanoparticle organization in sandwiched polymer brushes.

    PubMed

    Curk, Tine; Martinez-Veracoechea, Francisco J; Frenkel, Daan; Dobnikar, Jure

    2014-05-14

    The organization of nanoparticles inside grafted polymer layers is governed by the interplay of polymer-induced entropic interactions and the action of externally applied fields. Earlier work had shown that strong external forces can drive the formation of colloidal structures in polymer brushes. Here we show that external fields are not essential to obtain such colloidal patterns: we report Monte Carlo and molecular dynamics simulations that demonstrate that ordered structures can be achieved by compressing a "sandwich" of two grafted polymer layers, or by squeezing a coated nanotube, with nanoparticles in between. We show that the pattern formation can be efficiently controlled by the applied pressure, while the characteristic length-scale, that is, the typical width of the patterns, is sensitive to the length of the polymers. Based on the results of the simulations, we derive an approximate equation of state for nanosandwiches. PMID:24707901

  5. Polymer coating on the surface of zirconia nanoparticles by inductively coupled plasma polymerization

    NASA Astrophysics Data System (ADS)

    He, Wei; Guo, Zhigang; Pu, Yikang; Yan, Luting; Si, Wenjie

    2004-08-01

    Polymer coating on the surface of inorganic ceramic nanoparticles is beneficial to decrease agglomeration and improve dispersion in organic solvent in ceramic injection moulding technology. A layer of thin polymer film on zirconia nanoparticles is deposited by inductively coupled ethylene/nitrogen plasma. Transmission electron microscopy photographs indicate the presence of uniform polymer coatings and the thickness of the polymer layer is estimated as several nanometers. The chemical structure of the film is revealed as quasi-polyethylene long hydrocarbon chain by x-ray photoelectron spectroscopy examination.

  6. Organic polymer materials in the space environment

    NASA Astrophysics Data System (ADS)

    Chen, Jun; Ding, Nengwen; Li, Zhifeng; Wang, Wei

    2016-05-01

    The space environment is a complex environment full of microgravity, high vacuum, high and low temperature, strong radiation and plasma. Polymers used in the space environment will inevitably experience aging and degradation which result in changes of the material mechanics, physics and chemical properties, until they lose usefulness. To make a material that can be used for a long time and whose performance is not changed in the space environment, its ability to resist environmental factors must be excellent. Therefore, this paper provides an introduction to the harmful conditions in the space environment and their effects on the polymers, also it reviews the aging mechanisms of the adhesives used in the space environment and the effect of thermal cycling, stress, electromagnetic radiation and ionizing particles on the properties of polymers and optical devices, to provide the reference basis for selection, modification and reliability analysis of materials used in the space environment.

  7. Thiazolothiazole-linked porous organic polymers

    SciTech Connect

    Zhu, Xiang; Tian, Chengcheng; Jin, Tian; Wang, Jitong; Mahurin, Shannon Mark; Mei, Wenwen; Xiong, Yan; Hu, Jun; Feng, Xinliang; Liu, Honglai; Dai, Sheng

    2014-10-07

    In this study, thiazolothiazole-linked porous organic polymers have been synthesized from a facile catalyst-free condensation reaction between aldehydes and dithiooxamide under solvothermal conditions. The resultant porous frameworks exhibit a highly selective uptake of CO2 over N2 under ambient conditions.

  8. Thiazolothiazole-linked porous organic polymers

    DOE PAGES

    Zhu, Xiang; Tian, Chengcheng; Jin, Tian; Wang, Jitong; Mahurin, Shannon Mark; Mei, Wenwen; Xiong, Yan; Hu, Jun; Feng, Xinliang; Liu, Honglai; et al

    2014-10-07

    In this study, thiazolothiazole-linked porous organic polymers have been synthesized from a facile catalyst-free condensation reaction between aldehydes and dithiooxamide under solvothermal conditions. The resultant porous frameworks exhibit a highly selective uptake of CO2 over N2 under ambient conditions.

  9. Light-curing polymers for laser plasma generation

    NASA Astrophysics Data System (ADS)

    Loktionov, E. Y.; Protasov, Y. S.; Protasov, Y. Y.; Telekh, V. D.

    2015-07-01

    Solid rather than liquid media are used in pulsed laser plasma generators despite sophisticated transportation and dosing system need for a long-term operation. Liquid media could be more preferable due to transfer and dosing (down to 10-14 L) being well developed, but plasma generation of those results in intense droplet formation and kinetic energy losses. Combination of liquids transportation advantages and solids plasma generation efficiency might resolve this trade-off. Liquid-to-solid transition can be induced by cooling down to sublimation temperature, thermo-, photo- or electron induced polymerization (curing). Light cured polymers seem to be very useful as active media for plasma generators, since they can be solidified very fast (ca. 30 ms) just before impact. We considered experimentally several UV- curing polymer and mixtures ablation regimes and supply schemes for laser plasma generation. The best results were obtained for liquid polymer at high-power pulsed irradiation matching curing optimum wavelength.

  10. Ion-Conducting Organic/Inorganic Polymers

    NASA Technical Reports Server (NTRS)

    Kinder, James D.; Meador, Mary Ann B.

    2007-01-01

    Ion-conducting polymers that are hybrids of organic and inorganic moieties and that are suitable for forming into solid-electrolyte membranes have been invented in an effort to improve upon the polymeric materials that have been used previously for such membranes. Examples of the prior materials include perfluorosulfonic acid-based formulations, polybenzimidazoles, sulfonated polyetherketone, sulfonated naphthalenic polyimides, and polyethylene oxide (PEO)-based formulations. Relative to the prior materials, the polymers of the present invention offer greater dimensional stability, greater ease of formation into mechanically resilient films, and acceptably high ionic conductivities over wider temperature ranges. Devices in which films made of these ion-conducting organic/inorganic polymers could be used include fuel cells, lithium batteries, chemical sensors, electrochemical capacitors, electrochromic windows and display devices, and analog memory devices. The synthesis of a polymer of this type (see Figure 1) starts with a reaction between an epoxide-functionalized alkoxysilane and a diamine. The product of this reaction is polymerized by hydrolysis and condensation of the alkoxysilane group, producing a molecular network that contains both organic and inorganic (silica) links. The silica in the network contributes to the ionic conductivity and to the desired thermal and mechanical properties. Examples of other diamines that have been used in the reaction sequence of Figure 1 are shown in Figure 2. One can use any of these diamines or any combination of them in proportions chosen to impart desired properties to the finished product. Alternatively or in addition, one could similarly vary the functionality of the alkoxysilane to obtain desired properties. The variety of available alkoxysilanes and diamines thus affords flexibility to optimize the organic/inorganic polymer for a given application.

  11. Microspot target development with seeded and patterned plasma polymers

    SciTech Connect

    Letts, S.A.; Miller, D.E.; Corley, R.A.; Tillotson, T.M.; Witt, L.A.

    1984-12-10

    A new class of targets for laser fusion experiments was fabricated using plasma-deposition and etching technology. Plasma polymer coatings seeded with silicon or sulfur were deposited as 300..mu..m diameter microspots inside holes of equal diameter in a pure hydrocarbon polymer film. The target was designed to study large-scale plasma instabilities and measure the temperature and density histories of laser induced plasmas. The microspot target required three new development: freestanding stress-free CH films, technology to define and form holes in CH films, and development of seeded films deposited as 300..mu..m diameter discs, nested tightly in the precision holes. Hydrocarbon films were deposited by plasma polymerization or by solution casting (polystyrene in dichloromethane) onto potassium-chloide-coated glass slides. Holes were defined either by masking with a 300..mu..m diameter disc or by reactive ion etching through a washer mask. Sulfur or silicon seeded CH polymer microspots were deposited through a mask using plasma polymerization. Seeded polymer films were prepared with compositions as high as 12 atomic percent, with most diagnostic targets made with 2 a/o. Silicon seeded polymers, when deposited at 750 mtorr (100 Pa) pressure, wer transparent and colorless.

  12. Probing properties of cold radiofrequency plasma with polymer probe

    NASA Astrophysics Data System (ADS)

    Bormashenko, E.; Chaniel, G.; Multanen, V.

    2015-01-01

    The probe intended for the characterization of cold plasma is introduced. The probe allows the estimation of Debye length of cold plasma. The probe is based on the pronounced modification of surface properties (wettability) of polymer films by cold plasmas. The probe was tested with the cold radiofrequency inductive air plasma discharge. The Debye length and the concentration of charge carriers were estimated for various gas pressures. The reported results coincide reasonably with the corresponding values established by other methods. The probe makes possible measurement of characteristics of cold plasmas in closed chambers.

  13. Ion conducting organic/inorganic hybrid polymers

    NASA Technical Reports Server (NTRS)

    Meador, Maryann B. (Inventor); Kinder, James D. (Inventor)

    2010-01-01

    This invention relates to a series of organic/inorganic hybrid polymers that are easy to fabricate into dimensionally stable films with good ion-conductivity over a wide range of temperatures for use in a variety of applications. The polymers are prepared by the reaction of amines, preferably diamines and mixtures thereof with monoamines with epoxy-functionalized alkoxysilanes. The products of the reaction are polymerized by hydrolysis of the alkoxysilane groups to produce an organic-containing silica network. Suitable functionality introduced into the amine and alkoxysilane groups produce solid polymeric membranes which conduct ions for use in fuel cells, high-performance solid state batteries, chemical sensors, electrochemical capacitors, electro-chromic windows or displays, analog memory devices and the like.

  14. Polymer models of chromosome (re)organization

    NASA Astrophysics Data System (ADS)

    Mirny, Leonid

    Chromosome Conformation Capture technique (Hi-C) provides comprehensive information about frequencies of spatial interactions between genomic loci. Inferring 3D organization of chromosomes from these data is a challenging biophysical problem. We develop a top-down approach to biophysical modeling of chromosomes. Starting with a minimal set of biologically motivated interactions we build ensembles of polymer conformations that can reproduce major features observed in Hi-C experiments. I will present our work on modeling organization of human metaphase and interphase chromosomes. Our works suggests that active processes of loop extrusion can be a universal mechanism responsible for formation of domains in interphase and chromosome compaction in metaphase.

  15. Free radicals created by plasmas cause autohesive bonding in polymers

    SciTech Connect

    Awaja, Firas; McKenzie, David R.; Zhang Shengnan; James, Natalie

    2011-05-23

    We find that plasma immersion ion implantation of polymer surfaces enhances their autohesive bond strength when pressed together by more than a factor of five. Both polymerising (CH{sub 4}/O{sub 2}) and nonpolymerising (Ar) plasmas are effective. There is currently no satisfactory theory for predicting this remarkable phenomenon. We propose that free radicals created by the plasma treatment process diffuse to the interface and cause covalent bonds to form. This theory predicts the dependence of bond strength on plasma bias voltage, treatment time, and autohesive process conditions.

  16. Healable supramolecular polymers as organic metals.

    PubMed

    Armao, Joseph J; Maaloum, Mounir; Ellis, Thomas; Fuks, Gad; Rawiso, Michel; Moulin, Emilie; Giuseppone, Nicolas

    2014-08-13

    Organic materials exhibiting metallic behavior are promising for numerous applications ranging from printed nanocircuits to large area electronics. However, the optimization of electronic conduction in organic metals such as charge-transfer salts or doped conjugated polymers requires high crystallinity, which is detrimental to their processability. To overcome this problem, the combination of the electronic properties of metal-like materials with the mechanical properties of soft self-assembled systems is attractive but necessitates the absence of structural defects in a regular lattice. Here we describe a one-dimensional supramolecular polymer in which photoinduced through-space charge-transfer complexes lead to highly coherent domains with delocalized electronic states displaying metallic behavior. We also reveal that diffusion of supramolecular polarons in the nanowires repairs structural defects thereby improving their conduction. The ability to access metallic properties from mendable self-assemblies extends the current understanding of both fields and opens a wide range of processing techniques for applications in organic electronics. PMID:25053238

  17. Territorial Polymers and Large Scale Genome Organization

    NASA Astrophysics Data System (ADS)

    Grosberg, Alexander

    2012-02-01

    Chromatin fiber in interphase nucleus represents effectively a very long polymer packed in a restricted volume. Although polymer models of chromatin organization were considered, most of them disregard the fact that DNA has to stay not too entangled in order to function properly. One polymer model with no entanglements is the melt of unknotted unconcatenated rings. Extensive simulations indicate that rings in the melt at large length (monomer numbers) N approach the compact state, with gyration radius scaling as N^1/3, suggesting every ring being compact and segregated from the surrounding rings. The segregation is consistent with the known phenomenon of chromosome territories. Surface exponent β (describing the number of contacts between neighboring rings scaling as N^β) appears only slightly below unity, β 0.95. This suggests that the loop factor (probability to meet for two monomers linear distance s apart) should decay as s^-γ, where γ= 2 - β is slightly above one. The later result is consistent with HiC data on real human interphase chromosomes, and does not contradict to the older FISH data. The dynamics of rings in the melt indicates that the motion of one ring remains subdiffusive on the time scale well above the stress relaxation time.

  18. Application of atmospheric pressure plasma in polymer and composite adhesion

    NASA Astrophysics Data System (ADS)

    Yu, Hang

    An atmospheric pressure helium and oxygen plasma was used to investigate surface activation and bonding in polymer composites. This device was operated by passing 1.0-3.0 vol% of oxygen in helium through a pair of parallel plate metal electrodes powered by 13.56 or 27.12 MHz radio frequency power. The gases were partially ionized between the capacitors where plasma was generated. The reactive species in the plasma were carried downstream by the gas flow to treat the substrate surface. The temperature of the plasm gas reaching the surface of the substrate did not exceed 150 °C, which makes it suitable for polymer processing. The reactive species in the plasma downstream includes ~ 1016-1017 cm-3 atomic oxygen, ~ 1015 cm-3 ozone molecule, and ~ 10 16 cm-3 metastable oxygen molecule (O2 1Deltag). The substrates were treated at 2-5 mm distance from the exit of the plasma. Surface properties of the substrates were characterized using water contact angle (WCA), atomic force microscopy (AFM), infrared spectroscopy (IR), and X-ray photoelectron spectroscopy (XPS). Subsequently, the plasma treated samples were bonded adhesively or fabricated into composites. The increase in mechanical strength was correlated to changes in the material composition and structure after plasma treatment. The work presented hereafter establishes atmospheric pressure plasma as an effective method to activate and to clean the surfaces of polymers and composites for bonding. This application can be further expanded to the activation of carbon fibers for better fiber-resin interactions during the fabrication of composites. Treating electronic grade FR-4 and polyimide with the He/O2 plasma for a few seconds changed the substrate surface from hydrophobic to hydrophilic, which allowed complete wetting of the surface by epoxy in underfill applications. Characterization of the surface by X-ray photoelectron spectroscopy shows formation of oxygenated functional groups, including hydroxyl, carbonyl, and

  19. Adhesion Issues with Polymer/Oxide Barrier Coatings on Organic Displays

    SciTech Connect

    Matson, Dean W.; Martin, Peter M.; Graff, Gordon L.; Gross, Mark E.; Burrows, Paul E.; Bennett, Wendy D.; Hall, Michael G.; Mast, Eric S.; Bonham, Charles C.; Zumhoff, Mac R.; Rutherford, Nicole M.; Moro, Lorenza; Rosenblum, Martin; Praino, Robert F.; Visser, Robert J.

    2005-01-01

    Multilayer polymer/oxide coatings are being developed to protect sensitive organic display devices, such as OLEDs, from oxygen and water vapor permeation. The coatings have permeation levels ~ 10-6 g/m2/d for water vapor and ~10-6 cc/m2/d for oxygen, and are deposited by vacuum polymer technology. The coatings consist of either a base Al2O3 or acrylate polymer adhesion layer followed by alternating Al2O3/polymer layers. The polymer is used to decouple the 30 nm-thick Al2O3 barrier layers. Adhesion of the barrier coating to the substrate and display device is critical for the operating lifetime of the device. The substrate material could be any transparent flexible plastic. The coating technology can also be used to encapsulate organic-based electronic devices to protect them from atmospheric degradation. Plasma pretreatment is also needed for good adhesion to the substrate, but if it is too aggressive, it will damage the organic display device. We report on the effects of plasma treatment on the adhesion of barrier coatings to plastic substrates and the performance of OLED devices after plasma treatment and barrier coating deposition. We find that initial OLED performance is not significantly affected by the deposition process and plasma treatment, as demonstrated by luminosity and I-V curves.

  20. Solid polymer electrolyte composite membrane comprising plasma etched porous support

    DOEpatents

    Liu, Han; LaConti, Anthony B.

    2010-10-05

    A solid polymer electrolyte composite membrane and method of manufacturing the same. According to one embodiment, the composite membrane comprises a rigid, non-electrically-conducting support, the support preferably being a sheet of polyimide having a thickness of about 7.5 to 15 microns. The support has a plurality of cylindrical pores extending perpendicularly between opposing top and bottom surfaces of the support. The pores, which preferably have a diameter of about 0.1 to 5 microns, are made by plasma etching and preferably are arranged in a defined pattern, for example, with fewer pores located in areas of high membrane stress and more pores located in areas of low membrane stress. The pores are filled with a first solid polymer electrolyte, such as a perfluorosulfonic acid (PFSA) polymer. A second solid polymer electrolyte, which may be the same as or different than the first solid polymer electrolyte, may be deposited over the top and/or bottom of the first solid polymer electrolyte.

  1. Inorganic-organic composite solid polymer electrolytes

    SciTech Connect

    Abraham, K.M.; Koch, V.R.; Blakley, T.J.

    2000-04-01

    Inorganic-organic composite solid polymer electrolytes (CSPEs) have been prepared from the poly(ethylene oxide) (PEO)-like electrolytes of the general formula polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP)-PEO{sub n}-LiX and Li{sup +}-conducting ceramic powders. In the PEO-like electrolytes, PVdF-HFP is the copolymer of PVdF and HFP, PEO{sub n} is a nonvolatile oligomeric polyethylene oxide of {approximately}400 g/mol molecular weight, and LiX is lithium bis(trifluoroethylsulfonyl)imide. Two types of inorganic oxide ceramic powders were used: a highly Li{sup +}-conducting material of the composition 14 mol % Li{sub 2}O-9Al{sub 2}O{sub 3}-38TiO{sub 2}-39P{sub 2}O{sub 5}, and the poorly Li{sup +}-conducting Li-silicates Li{sub 4{minus}x}M{sub x}SiO{sub 4} where M is Ca or Mg and x is 0 or 0.05. The composite electrolytes can be prepared as thin membranes in which the Li{sup +} conductivity and good mechanical strength of the Li{sup +}-conducting inorganic ceramics are complemented by the structural flexibility and high conductivity of organic polymer electrolytes. Excellent electrochemical and thermal stabilities have been demonstrated for the electrolyte films. Li//composite electrolyte//LiCoO{sub 2} rechargeable cells have been fabricated and cycled at room temperature and 50 C.

  2. Efficient Computational Screening of Organic Polymer Photovoltaics.

    PubMed

    Kanal, Ilana Y; Owens, Steven G; Bechtel, Jonathon S; Hutchison, Geoffrey R

    2013-05-16

    There has been increasing interest in rational, computationally driven design methods for materials, including organic photovoltaics (OPVs). Our approach focuses on a screening "pipeline", using a genetic algorithm for first stage screening and multiple filtering stages for further refinement. An important step forward is to expand our diversity of candidate compounds, including both synthetic and property-based measures of diversity. For example, top monomer pairs from our screening are all donor-donor (D-D) combinations, in contrast with the typical donor-acceptor (D-A) motif used in organic photovoltaics. We also find a strong "sequence effect", in which the average HOMO-LUMO gap of tetramers changes by ∼0.2 eV as a function of monomer sequence (e.g., ABBA versus BAAB); this has rarely been explored in conjugated polymers. Beyond such optoelectronic optimization, we discuss other properties needed for high-efficiency organic solar cells, and applications of screening methods to other areas, including non-fullerene n-type materials, tandem cells, and improving charge and exciton transport. PMID:26282968

  3. Inorganic-organic composite polymers and methods of making

    DOEpatents

    Josowicz, Mira A.; Exarhos, Gregory J.

    1996-01-01

    The invention is a composition of an inorganic-organic polymer composite and a method of making it. The inorganic portion of the fundamental polymer composite polymer repeat is a speciated inorganic heterocyclic compound, and the organic portion of the polymer repeat is a cyclic organic radical anion compound having at least two charged sites. The composition of the present invention is made by combining a cyclic organic radical anion compound with a speciated inorganic heterocyclic compound by a nucleophilic substitution thereby forming a polymer of an inorganic-organic composite. The cyclic organic radical anion compound is preferably generated electrochemically. The nucleophilic substitution is alternately carried out chemically or electrochemically. A preferred embodiment of the present invention includes performing the nucleophilic substitution at the cathode of an electrochemical cell.

  4. Inorganic-organic composite polymers and methods of making

    DOEpatents

    Josowicz, M.A.; Exarhos, G.J.

    1996-10-29

    The invention is a composition of an inorganic-organic polymer composite and a method of making it. The inorganic portion of the fundamental polymer composite polymer repeat is a speciated inorganic heterocyclic compound, and the organic portion of the polymer repeat is a cyclic organic radical anion compound having at least two charged sites. The composition of the present invention is made by combining a cyclic organic radical anion compound with a speciated inorganic heterocyclic compound by a nucleophilic substitution thereby forming a polymer of an inorganic-organic composite. The cyclic organic radical anion compound is preferably generated electrochemically. The nucleophilic substitution is alternately carried out chemically or electrochemically. A preferred embodiment of the present invention includes performing the nucleophilic substitution at the cathode of an electrochemical cell. 2 figs.

  5. Plasma chemistry and organic synthesis

    NASA Technical Reports Server (NTRS)

    Tezuka, M.

    1980-01-01

    The characteristic features of chemical reactions using low temperature plasmas are described and differentiated from those seen in other reaction systems. A number of examples of applications of plasma chemistry to synthetic reactions are mentioned. The production of amino acids by discharge reactions in hydrocarbon-ammonia-water systems is discussed, and its implications for the origins of life are mentioned.

  6. Mechanisms of polymer degradation using an oxygen plasma generator

    NASA Technical Reports Server (NTRS)

    Colony, Joe A.; Sanford, Edward L.

    1987-01-01

    An RF oxygen plasma generator was used to produce polymer degradation which appears to be similar to that which has been observed in low Earth orbit. Mechanisms of this type of degradation were studied by collecting the reaction products in a cryogenic trap and identifying the molecular species using infrared, mass spectral, and X-ray diffraction techniques. No structurally dependent species were found from Kapton, Teflon, or Saran polymers. However, very reactive free radical entities are produced during the polymer degradation, as well as carbon dioxide and water. Reactions of the free radicals with the glass reaction vessel, with copper metal in the cold trap, and with a triphenyl phosphate scavenger in the cold trap, demonstrated the reactivity of the primary products.

  7. Plasma etching of polymers like SU8 and BCB

    NASA Astrophysics Data System (ADS)

    Mischke, Helge; Gruetzner, Gabi; Shaw, Mark

    2003-01-01

    Polymers with high viscosity, like SU8 and BCB, play a dominant role in MEMS application. Their behavior in a well defined etching plasma environment in a RIE mode was investigated. The 40.68 MHz driven bottom electrode generates higher etch rates combined with much lower bias voltages by a factor of ten or a higher efficiency of the plasma with lower damaging of the probe material. The goal was to obtain a well-defined process for the removal and structuring of SU8 and BCB using fluorine/oxygen chemistry, defined using variables like electron density and collision rate. The plasma parameters are measured and varied using a production proven technology called SEERS (Self Excited Electron Resonance Spectroscopy). Depending on application and on Polymer several metals are possible (e.g., gold, aluminum). The characteristic of SU8 and BCB was examined in the case of patterning by dry etching in a CF4/O2 chemistry. Etch profile and etch rate correlate surprisingly well with plasma parameters like electron density and electron collision rate, thus allowing to define to adjust etch structure in situ with the help of plasma parameters.

  8. Surface Modification of Polymer Photoresists in Fluorocarbon Plasma Etching

    NASA Astrophysics Data System (ADS)

    Wang, Mingmei; Kushner, Mark

    2009-10-01

    In plasma etching of high aspect ratio (AR), nm sized features, erosion of polymer photoresist (PR) can perturb the feature profile (e.g., bowing). Although cross-linking of PR due to ion and VUV fluxes could make it more resistive to etching, typically the PR etch rate is too high to maintain the pattern when the AR is large (> 20). In dielectric plasma etching using fluorocarbon gases, one strategy to prevent PR erosion is to deposit a (CxFy)n polymer on its surface. This process may be enhanced in dc-augmented capacitively coupled plasmas (CCPs) by sputtering of Si and CxFy from the dc biased electrode. Dangling bonds generated on the PR surface by ion, photon or electron bombardment trap Si and CxFy radicals forming Si-C and C-C bonds. Sputtered Si atoms can also react with CxFy radicals to produce more reactive CxFy-1 radicals which are more easily incorporated into the PR. In this talk we discuss scaling laws for radical production derived from a computational investigation of a dc-augmented dual frequency CCP reactor sustained in Ar/C4F8/O2. Fluxes of Si radicals are produced by sputtering of the dc electrode. Rates of polymer deposition on and sputtering of PR, and consequences of PR erosion (and deposition) on feature profiles will be discussed.

  9. Touching polymer chains by organic field-effect transistors

    PubMed Central

    Shao, Wei; Dong, Huanli; Wang, Zhigang; Hu, Wenping

    2014-01-01

    Organic field-effect transistors (OFETs) are used to directly “touch” the movement and dynamics of polymer chains, and then determine Tg. As a molecular-level probe, the conducting channel of OFETs exhibits several unique advantages: 1) it directly detects the motion and dynamics of polymer chain at Tg; 2) it allows the measurement of size effects in ultrathin polymer films (even down to 6 nm), which bridges the gap in understanding effects between surface and interface. This facile and reliable determination of Tg of polymer films and the understanding of polymer chain dynamics guide a new prospect for OFETs besides their applications in organic electronics and casting new light on the fundamental understanding of the nature of polymer chain dynamics. PMID:25227159

  10. Submerged Liquid Plasma for the Synthesis of Unconventional Nitrogen Polymers

    PubMed Central

    Senthilnathan, Jaganathan; Weng, Chih-Chiang; Liao, Jiunn-Der; Yoshimura, Masahiro

    2013-01-01

    Glow discharge polymerization is not well understood due to the rapid/complex reaction at the plasma/gas precursor interface. Plasma reaction in a submerged condition allows post-plasma-polymerization, leading to further polymer growth and thus a stable structure. Electron collision with acetonitrile at the interface initiates the formation of radical monomers, which undergoes further rearrangement to form low-molecular (LM) nitrogen polymers (NPs). The radical-rich LM NPs go through further polymerization, forming stable high-molecular (HM) NPs (as determined using liquid chromatography/mass spectrometry). LM NPs absorb light at a wavelength of 270 nm (λ max) whereas HM NPs show absorption at 420 nm (λ max), as determined from ultraviolet-visible absorption spectra. The fluorescence spectra of HM NPs show characteristic emission at 430 nm, which indicates the presence of nitrogen functional groups with external conjugation. The proposed structure of HM NPs is verified with different analytical instruments. PMID:23933661

  11. Organic/Inorganic Hybrid Polymer/Clay Nanocomposites

    NASA Technical Reports Server (NTRS)

    Park, Cheol; Connell, John W.; Smith, Joseph G., Jr.

    2003-01-01

    A novel class of polymer/clay nanocomposites has been invented in an attempt to develop transparent, lightweight, durable materials for a variety of aerospace applications. As their name suggests, polymer/ clay nanocomposites comprise organic/ inorganic hybrid polymer matrices containing platelet-shaped clay particles that have sizes of the order of a few nanometers thick and several hundred nanometers long. Partly because of their high aspect ratios and high surface areas, the clay particles, if properly dispersed in the polymer matrix at a loading level of 1 to 5 weight percent, impart unique combinations of physical and chemical properties that make these nanocomposites attractive for making films and coatings for a variety of industrial applications. Relative to the unmodified polymer, the polymer/ clay nanocomposites may exhibit improvements in strength, modulus, and toughness; tear, radiation, and fire resistance; and lower thermal expansion and permeability to gases while retaining a high degree of optical transparency.

  12. Distributed Pore Chemistry in Porous Organic Polymers in Tissue Culture Flasks

    NASA Technical Reports Server (NTRS)

    Koontz, Steven L. (Inventor)

    1999-01-01

    A method for making a biocompatible polymer article using a uniform atomic oxygen treatment is disclose. The substrate may be subsequently optionally grated with a compatibilizing compound. Compatibilizing compounds may include proteins, phosphorylcholine groups, platelet adhesion preventing polymers, albumin adhesion promoters, and the like. The compatibilized substrate may also have a living cell layer adhered thereto. The atomic oxygen is preferably produced by a flowing afterglow microwave discharge, wherein the substrate resides in a sidearm out of the plasma. Also, methods for culturing cells for various purposes using the various membranes are disclosed as well. Also disclosed are porous organic polymers having a distributed pore chemistry (DPC) comprising hydrophilic and hydrophobic regions, and a method for making the DPC by exposing the polymer to atomic oxygen wherein the rate of hydrophilization is greater than the rate of mass loss.

  13. Plasma deposition of polymer composite films incorporating nanocellulose whiskers

    NASA Astrophysics Data System (ADS)

    Samyn, P.; Airoudj, A.; Laborie, M.-P.; Mathew, A. P.; Roucoules, V.

    2011-11-01

    In a trend for sustainable engineering and functionalization of surfaces, we explore the possibilities of gas phase processes to deposit nanocomposite films. From an analysis of pulsed plasma polymerization of maleic anhydride in the presence of nanocellulose whiskers, it seems that thin nanocomposite films can be deposited with various patterns. By specifically modifying plasma parameters such as total power, duty cycle, and monomer gas pressure, the nanocellulose whiskers are either incorporated into a buckled polymer film or single nanocellulose whiskers are deposited on top of a polymeric film. The density of the latter can be controlled by modifying the exact positioning of the substrate in the reactor. The resulting morphologies are evaluated by optical microscopy, AFM, contact angle measurements and ellipsometry.

  14. Lipid organization of the plasma membrane.

    PubMed

    Ingólfsson, Helgi I; Melo, Manuel N; van Eerden, Floris J; Arnarez, Clément; Lopez, Cesar A; Wassenaar, Tsjerk A; Periole, Xavier; de Vries, Alex H; Tieleman, D Peter; Marrink, Siewert J

    2014-10-15

    The detailed organization of cellular membranes remains rather elusive. Based on large-scale molecular dynamics simulations, we provide a high-resolution view of the lipid organization of a plasma membrane at an unprecedented level of complexity. Our plasma membrane model consists of 63 different lipid species, combining 14 types of headgroups and 11 types of tails asymmetrically distributed across the two leaflets, closely mimicking an idealized mammalian plasma membrane. We observe an enrichment of cholesterol in the outer leaflet and a general non-ideal lateral mixing of the different lipid species. Transient domains with liquid-ordered character form and disappear on the microsecond time scale. These domains are coupled across the two membrane leaflets. In the outer leaflet, distinct nanodomains consisting of gangliosides are observed. Phosphoinositides show preferential clustering in the inner leaflet. Our data provide a key view on the lateral organization of lipids in one of life's fundamental structures, the cell membrane.

  15. Photo-oxidation of Polymers Synthesized by Plasma and Initiated CVD

    DOE PAGES

    Baxamusa, Salmaan H.; Suresh, Aravind; Ehrmann, Paul; Laurence, Ted; Hanania, Jiries; Hayes, Jeff; Harley, Stephen; Burkey, Daniel D.

    2015-11-09

    Plasma polymers are often limited by their susceptibility to spontaneous and photo-oxidation. We show that the unusual photoluminescence (PL) behavior of a plasma polymer of trans-2-butene is correlated with its photoluminescence strength. These photo-processes occur under blue light illumination (λ=405 nm), distinguishing them from traditional ultraviolet degradation of polymers. These photo-active defects are likely formed during the plasma deposition process and we show that a polymer synthesized using initiated (i)CVD, non-plasma method, has 1000× lower PL signal and enhanced photo-stability. In conclusion, non-plasma methods such as iCVD may therefore be a route to overcoming material aging issues that limit themore » adoption of plasma polymers.« less

  16. Photo-oxidation of Polymers Synthesized by Plasma and Initiated CVD

    SciTech Connect

    Baxamusa, Salmaan H.; Suresh, Aravind; Ehrmann, Paul; Laurence, Ted; Hanania, Jiries; Hayes, Jeff; Harley, Stephen; Burkey, Daniel D.

    2015-11-09

    Plasma polymers are often limited by their susceptibility to spontaneous and photo-oxidation. We show that the unusual photoluminescence (PL) behavior of a plasma polymer of trans-2-butene is correlated with its photoluminescence strength. These photo-processes occur under blue light illumination (λ=405 nm), distinguishing them from traditional ultraviolet degradation of polymers. These photo-active defects are likely formed during the plasma deposition process and we show that a polymer synthesized using initiated (i)CVD, non-plasma method, has 1000× lower PL signal and enhanced photo-stability. In conclusion, non-plasma methods such as iCVD may therefore be a route to overcoming material aging issues that limit the adoption of plasma polymers.

  17. Polymers as fuel for laser plasma thrusters: A correlation of thrust with material and plasma properties by mass spectrometry

    NASA Astrophysics Data System (ADS)

    Urech, Lukas; Lippert, Thomas; Phipps, Claude R.; Wokaun, Alexander

    2006-05-01

    The micro laser plasma thruster (μLPT) is a micro propulsion device, designed for the steering and propelling of small satellites (1 to 10 kg). A laser is focused onto a polymer layer on a substrate to form a plasma. The thrust produced by this plasma is used to control the satellite motion. To understand the influence of the specific properties of the polymers, three different "high"- and "low"-energetic polymers were tested: poly(vinyl chloride) (PVC) as a low-energetic reference polymer that showed the best properties among commercial polymers, a glycidyl azide polymer (GAP), and poly(vinyl nitrate) (PVN) as high-energetic polymers. It was necessary to dope the polymers with carbon nanoparticles or an IR-dye to achieve absorption at the irradiation wavelength in the near IR. Decomposition into smaller fragmentation was measured for the energetic polymers than for PVC corresponding well to the higher momentum coupling coefficient of the energetic polymers, which indicates that more thrust can be gained from a chosen incident laser power. The measurements of the kinetic energies of selected decomposition fragments revealed no significant difference between the different carbon doped polymers. Only for GAP with the IR-dye a change in the ratio between ions with different kinetic energy was observed with increasing fluence. More C + ions with higher kinetic energy were detected at higher fluences. No correlation between the kinetic energies of the ablation products and the specific impulse could be established for the obtained data.

  18. Liquid crystal-templated conducting organic polymers

    DOEpatents

    Stupp, Samuel I.; Hulvat, James F.

    2004-01-20

    A method of preparing a conductive polymeric film, includes providing a liquid crystal phase comprising a plurality of hydrophobic cores, the phase on a substrate, introducing a hydrophobic component to the phase, the component a conductive polymer precursor, and applying an electric potential across the liquid crystal phase, the potential sufficient to polymerize the said precursor.

  19. 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.

  20. 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

  1. Rational design of all organic polymer dielectrics

    NASA Astrophysics Data System (ADS)

    Sharma, Vinit; Wang, Chenchen; Lorenzini, Robert G.; Ma, Rui; Zhu, Qiang; Sinkovits, Daniel W.; Pilania, Ghanshyam; Oganov, Artem R.; Kumar, Sanat; Sotzing, Gregory A.; Boggs, Steven A.; Ramprasad, Rampi

    2014-09-01

    To date, trial and error strategies guided by intuition have dominated the identification of materials suitable for a specific application. We are entering a data-rich, modelling-driven era where such Edisonian approaches are gradually being replaced by rational strategies, which couple predictions from advanced computational screening with targeted experimental synthesis and validation. Here, consistent with this emerging paradigm, we propose a strategy of hierarchical modelling with successive downselection stages to accelerate the identification of polymer dielectrics that have the potential to surpass ‘standard’ materials for a given application. Successful synthesis and testing of some of the most promising identified polymers and the measured attractive dielectric properties (which are in quantitative agreement with predictions) strongly supports the proposed approach to material selection.

  2. Nonthermal plasma technology for organic destruction

    SciTech Connect

    Heath, W.O.; Birmingham, J.G.

    1995-06-01

    Pacific Northwest Laboratory (PNL) is investigating the use of nonthermal, electrically driven plasmas for destroying organic contaminants near ambient temperatures and pressures. Three different plasma systems have been developed to treat organics in air, water, and soil. These systems are the Gas-Phase Corona Reactor (GPCR)III for treating air, the Liquid-Phase Corona Reactor for treating water, and In Situ Corona for treating soils. This presentation focuses on recent technical developments, commercial status, and project costs of OPCR as a cost-effective alternative to other air-purification technologies that are now in use to treat off-gases from site-remediation efforts as well as industrial emissions.

  3. Study on Surface Modification of Polymer Films by Using Atmospheric Plasma Jet Source

    NASA Astrophysics Data System (ADS)

    Takemura, Yuichiro; Yamaguchi, Naohiro; Hara, Tamio

    2008-07-01

    Reactive gas plasma treatments of poly(ethylene terephthalate) (PET) and polyimide (Kapton) have been performed using an atmospheric plasmas jet source. Characteristics of surface modification have been examined by changing the distance between the plasma jet source and the treated sample, and by changing the working gas spaces. Simultaneously, each plasma jet source has been investigated by space-resolving spectroscopy in the UV/visible region. Polymer surfaces have been analyzed by X-ray photoelectron spectroscopy (XPS). A marked improvement in the hydrophilicity of the polymer surfaces has been made by using N2 or O2 plasma jet source with a very short exposure time of about 0.01 s, whereas the less improvement has been obtained using on air plasma jet source because of NOx compound production. Changes in the chemical states of C of the polymer surfaces have been observed in XPS spectra after N2 plasma jet spraying.

  4. Inorganic Metal Oxide/Organic Polymer Nanocomposites And Method Thereof

    DOEpatents

    Gash, Alexander E.; Satcher, Joe H.; Simpson, Randy

    2004-11-16

    A synthetic method for preparation of hybrid inorganic/organic energetic nanocomposites is disclosed herein. The method employs the use of stable metal in organic salts and organic solvents as well as an organic polymer with good solubility in the solvent system to produce novel nanocomposite energetic materials. In addition, fuel metal powders (particularly those that are oxophilic) can be incorporated into composition. This material has been characterized by thermal methods, energy-filtered transmission electron microscopy (EFTEM), N.sub.2 adsoprtion/desorption methods, and Fourier-Transform (FT-IR) spectroscopy. According to these characterization methods the organic polymer phase fills the nanopores of the material, providing superb mixing of the component phases in the energetic nanocomposite.

  5. The Organic Chemistry of Conducting Polymers

    SciTech Connect

    Tolbert, Laren Malcolm

    2014-12-01

    For the last several years, we have examined the fundamental principles of conduction in one-dimensional systems, i.e., molecular “wires”. It is, of course, widely recognized that such systems, as components of electronically conductive materials, function in a two- and three-dimensional milieu. Thus interchain hopping and grain-boundary resistivity are limiting conductivity factors in highly conductive materials, and overall conductivity is a function of through-chain and boundary hopping. We have given considerable attention to the basic principles underlying charge transport (the “rules of the game”) in two-dimensional systems by using model systems which allow direct observation of such processes, including the examination of tunneling and hopping as components of charge transfer. In related work, we have spent considerable effort on the chemistry of conjugated heteropolymers, most especially polythiophens, with the aim of using these most efficient of readily available electroactive polymers in photovoltaic devices.

  6. Patterning of conjugated polymers for organic optoelectronic devices.

    PubMed

    Xu, Youyong; Zhang, Fan; Feng, Xinliang

    2011-05-23

    Conjugated polymers have been attracting more and more attention because they possess various novel electrical, magnetical, and optical properties, which render them useful in modern organic optoelectronic devices. Due to their organic nature, conjugated polymers are light-weight and can be fabricated into flexible appliances. Significant research efforts have been devoted to developing new organic materials to make them competitive with their conventional inorganic counterparts. It is foreseeable that when large-scale industrial manufacture of the devices made from organic conjugated polymers is feasible, they would be much cheaper and have more functions. On one hand, in order to improve the performance of organic optoelectronic devices, it is essential to tune their surface morphologies by techniques such as patterning. On the other hand, patterning is the routine requirement for device processing. In this review, the recent progress in the patterning of conjugated polymers for high-performance optoelectronic devices is summarized. Patterning based on the bottom-up and top-down methods are introduced. Emerging new patterning strategies and future trends for conventional patterning techniques are discussed.

  7. Electrochemical characterization of plasma polymer coatings in corrosion protection of aluminum alloys

    NASA Astrophysics Data System (ADS)

    Chan, Yenfong; Yu, Qingsong

    2005-07-01

    Low-temperature plasma polymerization is a promising pretreatment technique to create environmentally friendly coating systems for corrosion protection of aluminum alloys. In this study, the pretreatment effects of plasma treatment and plasma polymerization on corrosion properties of alclad aluminum alloy 2024-T3 ([2A]) were investigated using electrochemical characterization techniques, including cyclic polarization (CP) and electrochemical impedance spectroscopy (EIS). The [2A] panels were coated with an ultrathin layer (~50 nm) of plasma polymers in a direct current (dc) glow discharge of trimethylsilane or its mixtures with one of two diatomic gases (O2 and N2). The CP measurement results showed that the plasma polymer coated [2A] panels exhibited more negative corrosion potentials (Ecorr), smaller corrosion currents (Icorr), and no surface passivation when compared with uncoated [2A] control panels. The lower values of Icorr imply a higher corrosion resistance on the plasma polymer coated [2A]. When investigated using EIS, these plasma polymer coated [2A] panels exhibited higher impedance (|Z|) at lower frequency when first immersed in electrolyte solution, yet degraded quickly to a similar level as uncoated controls within 1 day of immersion. These results illustrated that thin plasma polymer films provided a certain but very limited corrosion resistance to [2A] substrate; their dominant role in plasma interface engineered coating systems still relied mostly on their adhesion enhancement at metal/paint interface as observed in our previous studies.

  8. Microwave plasma conversion of volatile organic compounds.

    PubMed

    Ko, Youngsam; Yang, Gosu; Chang, Daniel P Y; Kennedy, Ian M

    2003-05-01

    A microwave-induced, steam/Ar/O2, plasma "torch" was operated at atmospheric pressure to determine the feasibility of destroying volatile organic compounds (VOCs) of concern. The plasma process can be coupled with adsorbent technology by providing steam as the fluid carrier for desorbing the VOCs from an adsorbent. Hence, N2 can be excluded by using a relatively inexpensive carrier gas, and thermal formation of oxides of nitrogen (NOx) is avoided in the plasma. The objectives of the study were to evaluate the technical feasibility of destroying VOCs from gas streams by using a commercially available microwave plasma torch and to examine whether significant byproducts were produced. Trichloroethene (TCE) and toluene (TOL) were added as representative VOCs of interest to a flow that contained Ar as a carrier gas in addition to O2 and steam. The O2 was necessary to ensure that undesirable byproducts were not formed in the process. Microwave power applied at 500-600 W was found to be sufficient to achieve the destruction of the test compounds, down to the detection limits of the gas chromatograph that was used in the analysis. Samples of the postmicrowave gases were collected on sorbent tubes for the analysis of dioxins and other byproducts. No hazardous byproducts were detected when sufficient O2 was added to the flow. The destruction efficiency at a fixed microwave power improved with the addition of steam to the flow that passed through the torch.

  9. Simple Organics and Biomonomers Identified in HCN Polymers: An Overview.

    PubMed

    Ruiz-Bermejo, Marta; Zorzano, María-Paz; Osuna-Esteban, Susana

    2013-01-01

    Hydrogen cyanide (HCN) is a ubiquitous molecule in the Universe. It is a compound that is easily produced in significant yields in prebiotic simulation experiments using a reducing atmosphere. HCN can spontaneously polymerise under a wide set of experimental conditions. It has even been proposed that HCN polymers could be present in objects such as asteroids, moons, planets and, in particular, comets. Moreover, it has been suggested that these polymers could play an important role in the origin of life. In this review, the simple organics and biomonomers that have been detected in HCN polymers, the analytical techniques and procedures that have been used to detect and characterise these molecules and an exhaustive classification of the experimental/environmental conditions that favour the formation of HCN polymers are summarised. Nucleobases, amino acids, carboxylic acids, cofactor derivatives and other compounds have been identified in HCN polymers. The great molecular diversity found in HCN polymers encourages their placement at the central core of a plausible protobiological system. PMID:25369814

  10. Simple Organics and Biomonomers Identified in HCN Polymers: An Overview

    PubMed Central

    Ruiz-Bermejo, Marta; Zorzano, María-Paz; Osuna-Esteban, Susana

    2013-01-01

    Hydrogen cyanide (HCN) is a ubiquitous molecule in the Universe. It is a compound that is easily produced in significant yields in prebiotic simulation experiments using a reducing atmosphere. HCN can spontaneously polymerise under a wide set of experimental conditions. It has even been proposed that HCN polymers could be present in objects such as asteroids, moons, planets and, in particular, comets. Moreover, it has been suggested that these polymers could play an important role in the origin of life. In this review, the simple organics and biomonomers that have been detected in HCN polymers, the analytical techniques and procedures that have been used to detect and characterise these molecules and an exhaustive classification of the experimental/environmental conditions that favour the formation of HCN polymers are summarised. Nucleobases, amino acids, carboxylic acids, cofactor derivatives and other compounds have been identified in HCN polymers. The great molecular diversity found in HCN polymers encourages their placement at the central core of a plausible protobiological system. PMID:25369814

  11. Photovoltaic effect in organic polymer-iodine complex

    NASA Technical Reports Server (NTRS)

    Hermann, A. M.; Rembaum, A.

    1967-01-01

    Certain charge transfer complexes formed from organic polymers and iodine generate appreciable voltages at relatively low impedances upon exposure to light. These films show promise in applications requiring chemically and electrically stable films as detectors of optical radiation and as energy converters in photovoltaic cells.

  12. Inorganic metal oxide/organic polymer nanocomposites and method thereof

    DOEpatents

    Gash, Alexander E.; Satcher, Joe H.; Simpson, Randy

    2004-03-30

    A synthetic method for preparation of hybrid inorganic/organic energetic nanocomposites is disclosed herein. The method employs the use of stable metal inorganic salts and organic solvents as well as an organic polymer with good solubility in the solvent system to produce novel nanocomposite energetic materials. In addition, fuel metal powders (particularly those that are oxophillic) can be incorporated into composition. This material has been characterized by thermal methods, energy-filtered transmission electron microscopy (EFTEM), N.sub.2 adsoprtion/desorption methods, and Fourier-Transform (FT-IR) spectroscopy. According to these characterization methods the organic polymer phase fills the nanopores of the composite material, providing superb mixing of the component phases in the energetic nanocomposite.

  13. A bifractal nature of reticular patterns induced by oxygen plasma on polymer films

    PubMed Central

    Bae, Junwan; Lee, I. J.

    2015-01-01

    Plasma etching was demonstrated to be a promising tool for generating self-organized nano-patterns on various commercial films. Unfortunately, dynamic scaling approach toward fundamental understanding of the formation and growth of the plasma-induced nano-structure has not always been straightforward. The temporal evolution of self-aligned nano-patterns may often evolve with an additional scale-invariance, which leads to breakdown of the well-established dynamic scaling law. The concept of a bifractal interface is successfully applied to reticular patterns induced by oxygen plasma on the surface of polymer films. The reticular pattern, composed of nano-size self-aligned protuberances and underlying structure, develops two types of anomalous dynamic scaling characterized by super-roughening and intrinsic anomalous scaling, respectively. The diffusion and aggregation of short-cleaved chains under the plasma environment are responsible for the regular distribution of the nano-size protuberances. Remarkably, it is uncovered that the dynamic roughening of the underlying structure is governed by a relaxation mechanism described by the Edwards-Wilkinson universality class with a conservative noise. The evidence for the basic phase, characterized by the negative roughness and growth exponents, has been elusive since its first theoretical consideration more than two decades ago. PMID:25997075

  14. Characterization and mechanism of He plasma pretreatment of nanoscale polymer masks for improved pattern transfer fidelity

    SciTech Connect

    Weilnboeck, F.; Metzler, D.; Kumar, N.; Oehrlein, G. S.; Bruce, R. L.; Engelmann, S.; Fuller, N.

    2011-12-26

    Roughening of nanoscale polymer masks during plasma etching (PE) limits feature critical dimensions in current and future lithographic technologies. Roughness formation of 193 nm photoresist (PR) is mechanistically explained by plasma-induced changes in mechanical properties introduced at the PR surface ({approx}2 nm) by ions and in parallel in the material bulk ({approx}200 nm) by ultraviolet (UV) plasma radiation. Synergistic roughening of polymer masks can be prevented by pretreating PR patterns with a high dose of He plasma UV exposure to saturate bulk material modifications. During subsequent PE, PR patterns are stabilized and exhibit improved etch resistance and reduced surface/line-edge roughness.

  15. Nitric oxide releasing plasma polymer coating with bacteriostatic properties and no cytotoxic side effects.

    PubMed

    Michl, Thomas D; Coad, Bryan R; Doran, Michael; Osiecki, Michael; Kafshgari, Morteza Hasanzadeh; Voelcker, Nicolas H; Hüsler, Amanda; Vasilev, Krasimir; Griesser, Hans J

    2015-04-25

    We report a stable plasma polymer coating, using isopentyl nitrite as a volatile precursor, which releases nitric oxide at bacteriostatic concentrations when contacted with water, inhibiting bacterial growth without cytotoxic side effects to human mesenchymal stem/stromal cells.

  16. The plasma footprint of an atmospheric pressure plasma jet on a flat polymer substrate and its relation to surface treatment

    NASA Astrophysics Data System (ADS)

    Onyshchenko, Iuliia; Nikiforov, Anton Yu.; De Geyter, Nathalie; Morent, Rino

    2016-08-01

    The aim of this work is to show the correlation between the plasma propagation in the footprint of an atmospheric pressure plasma jet on a flat polymer surface and the plasma treatment impact on the polymer properties. An argon plasma jet working in open air is used as plasma source, while PET thin films are used a substrates for plasma treatment. Light emission photographs are taken with an ICCD camera to have a close look at the generated structures in the plasma jet footprint on the surface. Water contact angle (WCA) measurement and X-ray photoelectron spectroscopy (XPS) analysis are also performed to obtain information about the impact of the plasma treatment on the PET surface characteristics. A variation in ICCD camera gate duration (1 µs, 100 µs, 50 ms) results in the photographs of the different plasma structures occurring during the plasma propagation on the flat PET surface. Contact angle measurements provide results on improvement of the PET hydrophilic character, while XPS analysis shows the distribution of atomic elements on the treated substrate surface. Light emission images help explaining the obtained WCA and XPS results. Contribution to the topical issue "6th Central European Symposium on Plasma Chemistry (CESPC-6)", edited by Nicolas Gherardi, Ester Marotta and Cristina Paradisi

  17. Low bandgap conjugated polymers for organic solar cells

    NASA Astrophysics Data System (ADS)

    Xu, Tao

    Organic solar cells are emerging as a potential solution to address the energy issue in the future. Functional materials that can achieve high performance are the main topics in my thesis. I went briefly to introduce the background and history first, emphasizing on the synthetic principles towards high performance copolymers. My second chapters is about the perturbation effect by introducing terminal chloroaryl in the side chain. A new type of monomer is presented in Chapter III and corresponding polymers are studied. Then we investigated the impact of polymerization conditions on the physical properties using PTB7 as the standard polymer. In the last, we further utilized TID unit to construct acceptor polymers and random copolymer. A PCE value of 7.55% was achieved.

  18. Biochemically designed polymers as self-organized materials

    NASA Astrophysics Data System (ADS)

    Alva, Shridhara; Sarma, Rupmoni; Marx, Kenneth A.; Kumar, Jayant; Tripathy, Sukant K.; Akkara, Joseph A.; Kaplan, David L.

    1997-02-01

    Self assembled molecular systems are a focus of attention for material scientists as they provide an inherent molecular level organization responsible for enhanced material properties. We have developed polymeric molecular systems with interesting optical properties by biochemical engineering, which can be self assembled to thin films. Horseradish peroxidase catalyzed polymerizations of phenolic monomers: 9-hydroxyquinoline-5-sulfonic acid, acid red and decyl ester (d&l isomers) of tyrosine, have been achieved in the presence of hydrogen peroxide. The polymer of 8- hydroxyquinoline-5-sulfonic acid acts as a polymeric ligand that can be used for metal ion sensing. The polymer of acid red, with azo functional groups in the polymer backbone, shows interesting optical properties. Amphiphilic derivatives of tyrosine self assemble into tubules from micelles in aqueous solutions. These tubules have been enzymatically polymerized to polymeric tubules. The tubules are of 5 micrometers average diameter and > 200 micrometers length. The formation and properties of these tubules are discussed.

  19. U.S. BURNING PLASMA ORGANIZATION ACTIVITIES

    SciTech Connect

    Raymond J. Fonck

    2009-08-11

    The national U.S. Burning Plasma Organization (USBPO) was formed to provide an umbrella structure in the U.S. fusion science research community. Its main purpose is the coordination of research activities in the U.S. program relevant to burning plasma science and preparations for participation in the international ITER experiment. This grant provided support for the continuing development and operations of the USBPO in its first years of existence. A central feature of the USBPO is the requirement for broad community participation in and governance of this effort. We concentrated on five central areas of activity of the USBPO during this grant period. These included: 1) activities of the Director and support staff in continuing management and development of the USBPO activity; 2) activation of the advisory Council; 3) formation and initial research activities of the research community Topical Groups; 4) formation of Task Groups to perform specific burning plasma related research and development activities; 5) integration of the USBPO community with the ITER Project Office as needed to support ITER development in the U.S.

  20. Compatibilization of All-Conjugated Polymer Blends for Organic Photovoltaics.

    PubMed

    Lombeck, Florian; Sepe, Alessandro; Thomann, Ralf; Friend, Richard H; Sommer, Michael

    2016-08-23

    Compatibilization of an immiscible binary blend comprising a conjugated electron donor and a conjugated electron acceptor polymer with suitable electronic properties upon addition of a block copolymer (BCP) composed of the same building blocks is demonstrated. Efficient compatibilization during melt-annealing is feasible when the two polymers are immiscible in the melt, i.e. above the melting point of ∼250 °C of the semicrystalline donor polymer P3HT. To generate immiscibility at these high temperatures, the acceptor polymer PCDTBT is equipped with fluorinated side chains leading to an increased Flory-Huggins interaction parameter. Compatibilization in bulk and thin films is demonstrated, showing that the photovoltaic performance of pristine microphase separated and nanostructured BCPs can also be obtained for compatibilized blend films containing low contents of 10-20 wt % BCP. Thermodynamically stable domain sizes range between several tens of microns for pure blends and ∼10 nm for pure block copolymers. In addition to controlling domain size, the amount of block copolymer added dictates the ratio of edge-on and face-on P3HT crystals, with compatibilized films showing an increasing amount of face-on P3HT crystals with increasing amount of compatibilizer. This study demonstrates the prerequisites and benefits of compatibilizing all-conjugated semicrystalline polymer blends for organic photovoltaics. PMID:27482842

  1. Compatibilization of All-Conjugated Polymer Blends for Organic Photovoltaics.

    PubMed

    Lombeck, Florian; Sepe, Alessandro; Thomann, Ralf; Friend, Richard H; Sommer, Michael

    2016-08-23

    Compatibilization of an immiscible binary blend comprising a conjugated electron donor and a conjugated electron acceptor polymer with suitable electronic properties upon addition of a block copolymer (BCP) composed of the same building blocks is demonstrated. Efficient compatibilization during melt-annealing is feasible when the two polymers are immiscible in the melt, i.e. above the melting point of ∼250 °C of the semicrystalline donor polymer P3HT. To generate immiscibility at these high temperatures, the acceptor polymer PCDTBT is equipped with fluorinated side chains leading to an increased Flory-Huggins interaction parameter. Compatibilization in bulk and thin films is demonstrated, showing that the photovoltaic performance of pristine microphase separated and nanostructured BCPs can also be obtained for compatibilized blend films containing low contents of 10-20 wt % BCP. Thermodynamically stable domain sizes range between several tens of microns for pure blends and ∼10 nm for pure block copolymers. In addition to controlling domain size, the amount of block copolymer added dictates the ratio of edge-on and face-on P3HT crystals, with compatibilized films showing an increasing amount of face-on P3HT crystals with increasing amount of compatibilizer. This study demonstrates the prerequisites and benefits of compatibilizing all-conjugated semicrystalline polymer blends for organic photovoltaics.

  2. Low-temperature oxidizing plasma surface modification and composite polymer thin-film fabrication techniques for tailoring the composition and behavior of polymer surfaces

    NASA Astrophysics Data System (ADS)

    Tompkins, Brendan D.

    This dissertation examines methods for modifying the composition and behavior of polymer material surfaces. This is accomplished using (1) low-temperature low-density oxidizing plasmas to etch and implant new functionality on polymers, and (2) plasma enhanced chemical vapor deposition (PECVD) techniques to fabricate composite polymer materials. Emphases are placed on the structure of modified polymer surfaces, the evolution of polymer surfaces after treatment, and the species responsible for modifying polymers during plasma processing. H2O vapor plasma modification of high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), polycarbonate (PC), and 75A polyurethane (PU) was examined to further our understanding of polymer surface reorganization leading to hydrophobic recovery. Water contact angles (wCA) measurements showed that PP and PS were the most susceptible to hydrophobic recovery, while PC and HDPE were the most stable. X-ray photoelectron spectroscopy (XPS) revealed a significant quantity of polar functional groups on the surface of all treated polymer samples. Shifts in the C1s binding energies (BE) with sample age were measured on PP and PS, revealing that surface reorganization was responsible for hydrophobic recovery on these materials. Differential scanning calorimetry (DSC) was used to rule out the intrinsic thermal properties as the cause of reorganization and hydrophobic recovery on HDPE, LDPE, and PP. The different contributions that polymer cross-linking and chain scission mechanisms make to polymer aging effects are considered. The H2O plasma treatment technique was extended to the modification of 0.2 microm and 3.0 microm track-etched polycarbonate (PC-TE) and track-etched polyethylene terephthalate (PET-TE) membranes with the goal of permanently increasing the hydrophilicity of the membrane surfaces. Contact angle measurements on freshly treated and aged samples confirmed the wettability of the

  3. Catalytic Polymer Multilayer Shell Motors for Separation of Organics.

    PubMed

    Lin, Zhihua; Wu, Zhiguang; Lin, Xiankun; He, Qiang

    2016-01-26

    A catalytic polymer multilayer shell motor has been developed, which effects fast motion-based separation of charged organics in water. The shell motors are fabricated by sputtering platinum onto the exposed surface of silica templates embedded in Parafilm, followed by layer-by-layer assembly of polyelectrolyte multilayers to the templates. The catalytic shell motors display high bubble propulsion with speeds of up to 260 μm s(-1) (13 body lengths per second). Moreover, the polyelectrolyte multilayers assembled at high pH (pH>9.0) adsorb approximately 89% of dye molecules from water, owing to the electrostatic interaction between the positively charged polymers and the anionic dye molecules, and subsequently release them at neutral pH in a microfluidic device. The efficient propulsion coupled with the effective adsorption behavior of the catalytic shell motors in a microfluidic device results in accelerated separation of organics in water and thus holds considerable promise for water analysis.

  4. Investigation of the growth mechanisms of diglyme plasma polymers on amyloid fibril networks

    NASA Astrophysics Data System (ADS)

    Li, Yali; Reynolds, Nicholas P.; Styan, Katie E.; Muir, Benjamin W.; Forsythe, John S.; Easton, Christopher D.

    2016-01-01

    Within the area of biomaterials research, the ability to tailor a materials surface chemistry while presenting a biomimetic topography is a useful tool for studying cell-surface and cell-cell interactions. For the study reported here we investigated the deposition of diglyme plasma polymer films (DGpp) onto amyloid fibril networks (AFNs), which have morphologies that mimic the extracellular matrix. We extend our previous work to observe that the nanoscale contours of the AFNs are well preserved even under thick layers of DGpp. The width of the surface features is positively correlated to the DGpp thickness. DGpp film growth conformed to the underlying fibril features, with a gradual smoothing out of the resultant surface topography. Further, to understand how the films grow on top of AFNs, X-ray photoelectron spectroscopy depth profiling was employed to determine the elemental composition within the coating, perpendicular to the plane of the substrate. It was found that AFNs partially fragment during the initial stage of plasma polymerisation, and these fragments then mix with the growing DGpp to form an intermixed interface region above the AFN. The findings in this study are likely applicable to situations where plasma polymerisation is used to apply an overcoat to adsorbed organic and/or biological molecules.

  5. Self-Organization in Turbulent Plasmas

    NASA Astrophysics Data System (ADS)

    Diamond, P. H.

    1997-11-01

    Self-Organization is a ubiquitous phenomenon in turbulent laboratory, space and astrophysical plasmas. In this review, we focus on the emergent behavior of large scale order in turbulent plasmas. Instances of such emergent behavior have the common elements of broken symmetry, criticality and auto-regulation, which collectively govern order parameter evolution. Here, we discuss three classic and illustrative paradigms of self-organization (s.-o.). Perhaps the simplest paradigm of s.-o. is that of criticality in one and two-dimensional cellular automata (CA). The goal is to understand the link between emergent macroscopic profile structure and microscopic automata rules, an end closely related to the calculation of tokamak confinement from gradient-driven micro-instabilities. Here, profile shape and stiffness may be calculated to good accuracy from Markov-chain algorithms, which agree well with direct implementation of the CA's with noise. For strongly-driven piles, hydrodynamic models reproduce ballistic propagation scaling and confirm the expectation that cross-gradient shear flows significantly alter avalanche statistics and scaling. A second paradigm of s.-o. is the magnetic dynamo, a classic realization of large scale s.-o. induced by small scale symmetry breaking. Here, it is the reflection symmetry of the small-scale turbulence which is broken, yielding a net helicity and alpha-effect. The structure of the self-organized state (i.e. scale of growth) is determined by alpha, which displays the footprint of small scale asymmetry. A novel element in the theory is the nonlinearity induced by rapid amplification of small scale magnetic fields. This, in turn, induces a nonlinear feedback which quenches the dynamo at finite amplitude. The quenching process is also manifested in passive scalar and magnetic flux transport. The third paradigm is the self-regulating shear flow. Here, small scale and large scale asymmetry are linked by a mechanism very similar to that

  6. Quantitative Measurement of Cationic Polymer Vector and Polymer-pDNA Polyplex Intercalation into the Cell Plasma Membrane.

    PubMed

    Vaidyanathan, Sriram; Anderson, Kevin B; Merzel, Rachel L; Jacobovitz, Binyamin; Kaushik, Milan P; Kelly, Christina N; van Dongen, Mallory A; Dougherty, Casey A; Orr, Bradford G; Banaszak Holl, Mark M

    2015-06-23

    Cationic gene delivery agents (vectors) are important for delivering nucleotides, but are also responsible for cytotoxicity. Cationic polymers (L-PEI, jetPEI, and G5 PAMAM) at 1× to 100× the concentrations required for translational activity (protein expression) induced the same increase in plasma membrane current of HEK 293A cells (30-50 nA) as measured by whole cell patch-clamp. This indicates saturation of the cell membrane by the cationic polymers. The increased currents induced by the polymers are not reversible for over 15 min. Irreversibility on this time scale is consistent with a polymer-supported pore or carpet model and indicates that the cell is unable to clear the polymer from the membrane. For polyplexes, although the charge concentration was the same (at N/P ratio of 10:1), G5 PAMAM and jetPEI polyplexes induced a much larger current increase (40-50 nA) than L-PEI polyplexes (<20 nA). Both free cationic lipid and lipid polyplexes induced a lower increase in current than cationic polymers (<20 nA). To quantify the membrane bound material, partition constants were measured for both free vectors and polyplexes into the HEK 293A cell membrane using a dye influx assay. The partition constants of free vectors increased with charge density of the vectors. Polyplex partition constants did not show such a trend. The long lasting cell plasma permeability induced by exposure to the polymer vectors or the polyplexes provides a plausible mechanism for the toxicity and inflammatory response induced by exposure to these materials.

  7. Quantitative Measurement of Cationic Polymer Vector and Polymer/pDNA Polyplex Intercalation into the Cell Plasma Membrane

    PubMed Central

    Vaidyanathan, Sriram; Anderson, Kevin B.; Merzel, Rachel L.; Jacobovitz, Binyamin; Kaushik, Milan P.; Kelly, Christina N.; van Dongen, Mallory A.; Dougherty, Casey A.; Orr, Bradford G.; Holl, Mark M. Banaszak

    2016-01-01

    Cationic gene delivery agents (vectors) are important for delivering nucleotides, but are also responsible for cytotoxicity. Cationic polymers (L-PEI, jetPEI, and G5 PAMAM) at 1x to 100x the concentrations required for translational activity (protein expression) induced the same increase in plasma membrane current of HEK 293A cells (30-50 nA) as measured by whole cell patch-clamp. This indicates saturation of the cell membrane by the cationic polymers. The increased currents induced by the polymers are not reversible for over 15 minutes. Irreversibility on this time scale is consistent with a polymer-supported pore or carpet model and indicates that the cell is unable to clear the polymer from the membrane. For polyplexes, although the charge concentration was the same (at N: P ration of 10:1), G5 PAMAM and jetPEI polyplexes induced a much larger current increase (40- 50 nA) than L-PEI polyplexes (< 20 nA). Both free cationic lipid and lipid polyplexes induced a lower increase in current than cationic polymers (< 20 nA). To quantify the membrane bound material, partition constants were measured for both free vectors and polyplexes into the HEK 293A cell membrane using a dye influx assay. The partition constants of free vectors increased with charge density of the vectors. Polyplex partition constants did not show such a trend. The long lasting cell plasma permeability induced by exposure to the polymer vectors or the polyplexes provides a plausible mechanism for the toxicity and inflammatory response induced by exposure to these materials. PMID:25952271

  8. Efficient barrier for charge injection in polyethylene by silver nanoparticles/plasma polymer stack

    NASA Astrophysics Data System (ADS)

    Milliere, L.; Makasheva, K.; Laurent, C.; Despax, B.; Teyssedre, G.

    2014-09-01

    Charge injection from a metal/insulator contact is a process promoting the formation of space charge in polymeric insulation largely used in thick layers in high voltage equipment. The internal charge perturbs the field distribution and can lead to catastrophic failure either through its electrostatic effects or through energetic processes initiated under charge recombination and/or hot electrons effects. Injection is still ill-described in polymeric insulation due to the complexity of the contact between the polymer chains and the electrodes. Barrier heights derived from the metal work function and the polymer electronic affinity do not provide a good description of the measurements [Taleb et al., IEEE Trans. Dielectr. Electr. Insul. 20, 311-320 (2013)]. Considering the difficulty to describe the contact properties and the need to prevent charge injection in polymers for high voltage applications, we developed an alternative approach by tailoring the interface properties by the silver nanoparticles (AgNPs)/plasma polymer stack, deposited on the polymer film. Due to their small size, the AgNPs, covered by a very thin film of plasma polymer, act as deep traps for the injected charges thereby stabilizing the interface from the point of view of charge injection. After a quick description of the method for elaborating the nanostructured layer near the contact, it is demonstrated how the AgNPs/plasma polymer stack effectively prevents, in a spectacular way, the formation of bulk space charge.

  9. Preparation and Performance of Plasma/Polymer Composite Coatings on Magnesium Alloy

    NASA Astrophysics Data System (ADS)

    Bakhsheshi-Rad, H. R.; Hamzah, E.; Bagheriyan, S.; Daroonparvar, M.; Kasiri-Asgarani, M.; Shah, A. M.; Medraj, M.

    2016-07-01

    A triplex plasma (NiCoCrAlHfYSi/Al2O3·13%TiO2)/polycaprolactone composite coating was successfully deposited on a Mg-1.2Ca alloy by a combination of atmospheric plasma spraying and dip-coating techniques. The NiCoCrAlHfYSi (MCrAlHYS) coating, as the first layer, contained a large number of voids, globular porosities, and micro-cracks with a thickness of 40-50 μm, while the Al2O3·13%TiO2 coating, as the second layer, presented a unique bimodal microstructure with a thickness of 70-80 μm. The top layer was a hydrophobic polymer, which effectively sealed the porosities of plasma layers. The results of micro-hardness and bonding strength tests showed that the plasma coating presented excellent hardness (870 HV) and good bonding strength (14.8 MPa). However, the plasma/polymer coatings interface exhibited low bonding strength (8.6 MPa). The polymer coating formed thick layer (100-110 μm) that homogeneously covered the surface of the plasma layers. Contact angle measurement showed that polymer coating over plasma layers significantly decreased surface wettability. The corrosion current density (i corr) of an uncoated sample (262.7 µA/cm2) decreased to 76.9 µA/cm2 after plasma coatings were applied. However, it was found that the i corr decreased significantly to 0.002 µA/cm2 after polymer sealing of the porous plasma layers.

  10. Preparation and Performance of Plasma/Polymer Composite Coatings on Magnesium Alloy

    NASA Astrophysics Data System (ADS)

    Bakhsheshi-Rad, H. R.; Hamzah, E.; Bagheriyan, S.; Daroonparvar, M.; Kasiri-Asgarani, M.; Shah, A. M.; Medraj, M.

    2016-09-01

    A triplex plasma (NiCoCrAlHfYSi/Al2O3·13%TiO2)/polycaprolactone composite coating was successfully deposited on a Mg-1.2Ca alloy by a combination of atmospheric plasma spraying and dip-coating techniques. The NiCoCrAlHfYSi (MCrAlHYS) coating, as the first layer, contained a large number of voids, globular porosities, and micro-cracks with a thickness of 40-50 μm, while the Al2O3·13%TiO2 coating, as the second layer, presented a unique bimodal microstructure with a thickness of 70-80 μm. The top layer was a hydrophobic polymer, which effectively sealed the porosities of plasma layers. The results of micro-hardness and bonding strength tests showed that the plasma coating presented excellent hardness (870 HV) and good bonding strength (14.8 MPa). However, the plasma/polymer coatings interface exhibited low bonding strength (8.6 MPa). The polymer coating formed thick layer (100-110 μm) that homogeneously covered the surface of the plasma layers. Contact angle measurement showed that polymer coating over plasma layers significantly decreased surface wettability. The corrosion current density ( i corr) of an uncoated sample (262.7 µA/cm2) decreased to 76.9 µA/cm2 after plasma coatings were applied. However, it was found that the i corr decreased significantly to 0.002 µA/cm2 after polymer sealing of the porous plasma layers.

  11. Site-Specific Zwitterionic Polymer Conjugates of a Protein Have Long Plasma Circulation.

    PubMed

    Bhattacharjee, Somnath; Liu, Wenge; Wang, Wei-Han; Weitzhandler, Isaac; Li, Xinghai; Qi, Yizhi; Liu, Jinyao; Pang, Yan; Hunt, Donald F; Chilkoti, Ashutosh

    2015-11-01

    Many proteins suffer from suboptimal pharmacokinetics (PK) that limit their utility as drugs. The efficient synthesis of polymer conjugates of protein drugs with tunable PK to optimize their in vivo efficacy is hence critical. We report here the first study of the in vivo behavior of a site-specific conjugate of a zwitterionic polymer and a protein. To synthesize the conjugate, we first installed an initiator for atom-transfer radical polymerization (ATRP) at the N terminus of myoglobin (Mb-N-Br). Subsequently, in situ ATRP was carried out in aqueous buffer to grow an amine-functionalized polymer from Mb-N-Br. The cationic polymer was further derivatized to two zwitterionic polymers by treating the amine groups of the cationic polymer with iodoacetic acid to obtain poly(carboxybetaine methacrylate) with a one-carbon spacer (PCBMA; C1 ), and sequentially with 3-iodopropionic acid and iodoacetic acid to obtain PCBMA(mix) with a mixture of C1 and C2 spacers. The Mb-N-PCBMA polymer conjugates had a longer in vivo plasma half-life than a PEG-like comb polymer conjugate of similar molecular weights (MW). The structure of the zwitterion plays a role in controlling the in vivo behavior of the conjugate, as the PCBMA conjugate with a C1 spacer had significantly longer plasma circulation than the conjugate with a mixture of C1 and C2 spacers.

  12. Organic and organic-inorganic hybrid polymer thin films deposited by PECVD using TEOS and cyclohexene for ULSI interlayer-dielectric application

    NASA Astrophysics Data System (ADS)

    Seo, Hyeon Jin; Nam, Sang-Hun; Kim, Sungsoo; Boo, Jin-Hyo

    2015-11-01

    Organic and organic-inorganic hybrid polymer thin films were deposited on Si(1 0 0) substrates at various ratios of TEOS (tetraethoxysilane) to cyclohexene by the plasma enhanced chemical vapor deposition (PECVD) method. The as-grown polymerized thin films were first analyzed by FT-IR and XPS. The results of FT-IR showed that the hybrid polymer thin films were polymerized with each fragmented precursor. The XPS results showed the chemical species and binding energies of each species. The Si 2p core-level spectra from the hybrid polymer thin film showed the status of the Si oxidation number. Impedance analysis was utilized for the measurement of the capacitance values and I-V curves, and an ultra low-k value and leakage current density of 1.75 and 10-9 A/cm2 at 1 MV/cm were obtained, respectively.

  13. PATTERN RECOGNITION STUDIES OF HALOGENATED ORGANIC COMPOUNDS USING CONDUCTING POLYMER SENSOR ARRAYS. (R825323)

    EPA Science Inventory

    Direct measurement of volatile and semivolatile halogenated organic compounds of environmental interest was carried out using arrays of conducting polymer sensors. Mathematical expressions of the sensor arrays using microscopic polymer network model is described. A classical, non...

  14. Principles of chromatin organization in yeast: relevance of polymer models to describe nuclear organization and dynamics.

    PubMed

    Wang, Renjie; Mozziconacci, Julien; Bancaud, Aurélien; Gadal, Olivier

    2015-06-01

    Nuclear organization can impact on all aspects of the genome life cycle. This organization is thoroughly investigated by advanced imaging and chromosome conformation capture techniques, providing considerable amount of datasets describing the spatial organization of chromosomes. In this review, we will focus on polymer models to describe chromosome statics and dynamics in the yeast Saccharomyces cerevisiae. We suggest that the equilibrium configuration of a polymer chain tethered at both ends and placed in a confined volume is consistent with the current literature, implying that local chromatin interactions play a secondary role in yeast nuclear organization. Future challenges are to reach an integrated multi-scale description of yeast chromosome organization, which is crucially needed to improve our understanding of the regulation of genomic transaction. PMID:25956973

  15. Plasma polymer-functionalized silica particles for heavy metals removal.

    PubMed

    Akhavan, Behnam; Jarvis, Karyn; Majewski, Peter

    2015-02-25

    Highly negatively charged particles were fabricated via an innovative plasma-assisted approach for the removal of heavy metal ions. Thiophene plasma polymerization was used to deposit sulfur-rich films onto silica particles followed by the introduction of oxidized sulfur functionalities, such as sulfonate and sulfonic acid, via water-plasma treatments. Surface chemistry analyses were conducted by X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectroscopy. Electrokinetic measurements quantified the zeta potentials and isoelectric points (IEPs) of modified particles and indicated significant decreases of zeta potentials and IEPs upon plasma modification of particles. Plasma polymerized thiophene-coated particles treated with water plasma for 10 min exhibited an IEP of less than 3.5. The effectiveness of developed surfaces in the adsorption of heavy metal ions was demonstrated through copper (Cu) and zinc (Zn) removal experiments. The removal of metal ions was examined through changing initial pH of solution, removal time, and mass of particles. Increasing the water plasma treatment time to 20 min significantly increased the metal removal efficiency (MRE) of modified particles, whereas further increasing the plasma treatment time reduced the MRE due to the influence of an ablation mechanism. The developed particulate surfaces were capable of removing more than 96.7% of both Cu and Zn ions in 1 h. The combination of plasma polymerization and oxidative plasma treatment is an effective method for the fabrication of new adsorbents for the removal of heavy metals.

  16. Plasma polymer-functionalized silica particles for heavy metals removal.

    PubMed

    Akhavan, Behnam; Jarvis, Karyn; Majewski, Peter

    2015-02-25

    Highly negatively charged particles were fabricated via an innovative plasma-assisted approach for the removal of heavy metal ions. Thiophene plasma polymerization was used to deposit sulfur-rich films onto silica particles followed by the introduction of oxidized sulfur functionalities, such as sulfonate and sulfonic acid, via water-plasma treatments. Surface chemistry analyses were conducted by X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectroscopy. Electrokinetic measurements quantified the zeta potentials and isoelectric points (IEPs) of modified particles and indicated significant decreases of zeta potentials and IEPs upon plasma modification of particles. Plasma polymerized thiophene-coated particles treated with water plasma for 10 min exhibited an IEP of less than 3.5. The effectiveness of developed surfaces in the adsorption of heavy metal ions was demonstrated through copper (Cu) and zinc (Zn) removal experiments. The removal of metal ions was examined through changing initial pH of solution, removal time, and mass of particles. Increasing the water plasma treatment time to 20 min significantly increased the metal removal efficiency (MRE) of modified particles, whereas further increasing the plasma treatment time reduced the MRE due to the influence of an ablation mechanism. The developed particulate surfaces were capable of removing more than 96.7% of both Cu and Zn ions in 1 h. The combination of plasma polymerization and oxidative plasma treatment is an effective method for the fabrication of new adsorbents for the removal of heavy metals. PMID:25603034

  17. Atomic Oxygen Durability Evaluation of Protected Polymers Using Thermal Energy Plasma Systems

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.; Rutledge, Sharon K.; Degroh, Kim K.; Stidham, Curtis R.; Gebauer, Linda; Lamoreaux, Cynthia M.

    1995-01-01

    The durability evaluation of protected polymers intended for use in low Earth orbit (LEO) has necessitated the use of large-area, high-fluence, atomic oxygen exposure systems. Two thermal energy atomic oxygen exposure systems which are frequently used for such evaluations are radio frequency (RF) plasma ashers and electron cyclotron resonance plasma sources. Plasma source testing practices such as ample preparation, effective fluence prediction, atomic oxygen flux determination, erosion measurement, operational considerations, and erosion yield measurements are presented. Issues which influence the prediction of in-space durability based on ground laboratory thermal energy plasma system testing are also addressed.

  18. Initiation of atomic layer deposition of metal oxides on polymer substrates by water plasma pretreatment

    SciTech Connect

    Steven Brandt, E.; Grace, Jeremy M.

    2012-01-15

    The role of surface hydroxyl content in atomic layer deposition (ALD) of aluminum oxide (AO) on polymers is demonstrated by performing an atomic layer deposition of AO onto a variety of polymer types, before and after pretreatment in a plasma struck in water vapor. The treatment and deposition reactions are performed in situ in a high vacuum chamber that is interfaced to an x-ray photoelectron spectrometer to prevent adventitious exposure to atmospheric contaminants. X-ray photoelectron spectroscopy is used to follow the surface chemistries of the polymers, including theformation of surface hydroxyls and subsequent growth of AO by ALD. Using dimethyl aluminum isopropoxide and water as reactants, ALD is obtained for water-plasma-treated poly(styrene) (PS), poly(propylene) (PP), poly(vinyl alcohol) (PVA), and poly(ethylene naphthalate) (PEN). For PS, PP, and PEN, initial growth rates of AO on the native (untreated) polymers are at least an order of magnitude lower than on the same polymer surface following the plasma treatment. By contrast, native PVA is shown to initiate ALD of AO as a result of the presence of intrinsic surface hydroxyls that are derived from the repeat unit of this polymer.

  19. Improved adhesion of dense silica coatings on polymers by atmospheric plasma pretreatment.

    PubMed

    Cui, Linying; Ranade, Alpana N; Matos, Marvi A; Dubois, Geraud; Dauskardt, Reinhold H

    2013-09-11

    Oxygen atmospheric plasma was used to pretreat polycarbonate (PC) and stretched poly(methyl methacrylate) (PMMA) surfaces in order to enhance the adhesion of the dense silica coatings deposited by atmospheric plasma on the polymer substrates. The treatment time and chemical structure of the polymers were found to be important factors. For PC, a short treatment increased the adhesion energy, while longer treatment times decreased the adhesion. In contrast, plasma pretreatment monotonically decreased the adhesion of PMMA, and pristine PMMA exhibited much higher adhesion than the PC counterpart. We found that adhesion enhancement was achieved through improved chemical bonding, chain interdiffusion, and mechanical interlocking at the coating/substrate interface, after a short atmospheric plasma treatment. Decreased adhesion resulted from overoxidation and low-molecular-weight weak layer formation on the polymer surface by prolonged atmospheric plasma treatment. The dramatic differences in the behavior of PC and PMMA in relation to the plasma treatment time were due to their dissimilar resistance to atmospheric plasma exposure.

  20. Fabrication and structure of "polymer nanosphere multilayered organization".

    PubMed

    Fujimori, Atsuhiro; Kaneko, Yohei; Kikkawa, Takahiro; Chiba, Satoshi; Shibasaki, Yuji

    2014-03-15

    We constructed a multiparticle layered organization of aromatic polyamides with rigid main chains and flexible side chains by the Langmuir-Blodgett (LB) technique, which resulted in a highly regular arrangement along the c-axis. The particle arrangement was estimated by performing out-of-plane X-ray diffraction (XRD) analysis and atomic force microscopic (AFM) observation. The results suggest that a double-particle layered structure (Y-type) is formed by the LB technique, forming amphiphilic particles at the air/water interface. Copolymers with highly hydrophobic carbazole contents and both hydrogenated and fluorinated side-chains also formed a single-particle layer at the air/water interface and exhibited multiparticle layers by a LB technique. Therefore, it is possible to control the formation of single- and double-particle layered structure using these techniques. Further, it was found that multiparticle layered organization of polymer nanospheres and polymer nanosheets could be formed simultaneously with the same component material.

  1. Catalytic Polymer Multilayer Shell Motors for Separation of Organics.

    PubMed

    Lin, Zhihua; Wu, Zhiguang; Lin, Xiankun; He, Qiang

    2016-01-26

    A catalytic polymer multilayer shell motor has been developed, which effects fast motion-based separation of charged organics in water. The shell motors are fabricated by sputtering platinum onto the exposed surface of silica templates embedded in Parafilm, followed by layer-by-layer assembly of polyelectrolyte multilayers to the templates. The catalytic shell motors display high bubble propulsion with speeds of up to 260 μm s(-1) (13 body lengths per second). Moreover, the polyelectrolyte multilayers assembled at high pH (pH>9.0) adsorb approximately 89% of dye molecules from water, owing to the electrostatic interaction between the positively charged polymers and the anionic dye molecules, and subsequently release them at neutral pH in a microfluidic device. The efficient propulsion coupled with the effective adsorption behavior of the catalytic shell motors in a microfluidic device results in accelerated separation of organics in water and thus holds considerable promise for water analysis. PMID:26632275

  2. Intrinsic electrical conductivity of nanostructured metal-organic polymer chains.

    PubMed

    Hermosa, Cristina; Vicente Álvarez, Jose; Azani, Mohammad-Reza; Gómez-García, Carlos J; Fritz, Michelle; Soler, Jose M; Gómez-Herrero, Julio; Gómez-Navarro, Cristina; Zamora, Félix

    2013-01-01

    One-dimensional conductive polymers are attractive materials because of their potential in flexible and transparent electronics. Despite years of research, on the macro- and nano-scale, structural disorder represents the major hurdle in achieving high conductivities. Here we report measurements of highly ordered metal-organic nanoribbons, whose intrinsic (defect-free) conductivity is found to be 10(4) S m(-1), three orders of magnitude higher than that of our macroscopic crystals. This magnitude is preserved for distances as large as 300 nm. Above this length, the presence of structural defects (~ 0.5%) gives rise to an inter-fibre-mediated charge transport similar to that of macroscopic crystals. We provide the first direct experimental evidence of the gapless electronic structure predicted for these compounds. Our results postulate metal-organic molecular wires as good metallic interconnectors in nanodevices.

  3. The polymer-like organic material in the Orgueil meteorite

    NASA Technical Reports Server (NTRS)

    Bandurski, E. L.; Nagy, B.

    1976-01-01

    Results are reported for analysis of polymeric organic material contained in powder from the Orgueil chondrite, using a stepwise high-vacuum pyrolysis-gas chromatography-mass spectrometry technique. Pyrolysis products obtained include a series of alkanes and alkenes to C8, an extensive series of alkylbenzene isomers, thiophene, alkylthiophenes, benzothiophene, acetonitrile, acrylonitrile, benzonitrile, acetone, and phenol. Most of these products are shown to be similar both qualitatively and quantitatively to those previously obtained from solvent-extracted Allende powder, indicating a basically aromatic and heteroaromatic polymer matrix with short aliphatic bridges or side chains. The production of acrylonitrile, acetonitrile, and benzonitrile (common breakdown products of amino acids) from the insoluble organic material is taken to suggest that amino acids exist in an insoluble form, perhaps as peptides, in the meteorite's polymeric component. Similarities between the structure of the Orgueil polymeric material and terrestrial kerogen are discussed which raise the possibility that both might have been produced in part by similar reactions.

  4. Tuning hyperfine fields in conjugated polymers for coherent organic spintronics.

    PubMed

    Lee, Sang-Yun; Paik, Seo-Young; McCamey, Dane R; Yu, Justin; Burn, Paul L; Lupton, John M; Boehme, Christoph

    2011-02-23

    An appealing avenue for organic spintronics lies in direct coherent control of the spin population by means of pulsed electron spin resonance techniques. Whereas previous work has focused on the electrical detection of coherent spin dynamics, we demonstrate here the equivalence of an all-optical approach, allowing us to explore the influence of materials chemistry on the spin dynamics. We show that deuteration of the conjugated polymer side groups weakens the local hyperfine fields experienced by electron-hole pairs, thereby lowering the threshold for the resonant radiation intensity at which coherent coupling and spin beating occur. The technique is exquisitively sensitive to previously obscured material properties and offers a route to quantifying and tuning hyperfine fields in organic semiconductors.

  5. Effects of Alkylthio and Alkoxy Side Chains in Polymer Donor Materials for Organic Solar Cells.

    PubMed

    Cui, Chaohua; Wong, Wai-Yeung

    2016-02-01

    Side chains play a considerable role not only in improving the solubility of polymers for solution-processed device fabrication, but also in affecting the molecular packing, electron affinity and thus the device performance. In particular, electron-donating side chains show unique properties when employed to tune the electronic character of conjugated polymers in many cases. Therefore, rational electron-donating side chain engineering can improve the photovoltaic properties of the resulting polymer donors to some extent. Here, a survey of some representative examples which use electron-donating alkylthio and alkoxy side chains in conjugated organic polymers for polymer solar cell applications will be presented. It is envisioned that an analysis of the effect of such electron-donating side chains in polymer donors would contribute to a better understanding of this kind of side chain behavior in solution-processed conjugated organic polymers for polymer solar cells.

  6. Effects of Alkylthio and Alkoxy Side Chains in Polymer Donor Materials for Organic Solar Cells.

    PubMed

    Cui, Chaohua; Wong, Wai-Yeung

    2016-02-01

    Side chains play a considerable role not only in improving the solubility of polymers for solution-processed device fabrication, but also in affecting the molecular packing, electron affinity and thus the device performance. In particular, electron-donating side chains show unique properties when employed to tune the electronic character of conjugated polymers in many cases. Therefore, rational electron-donating side chain engineering can improve the photovoltaic properties of the resulting polymer donors to some extent. Here, a survey of some representative examples which use electron-donating alkylthio and alkoxy side chains in conjugated organic polymers for polymer solar cell applications will be presented. It is envisioned that an analysis of the effect of such electron-donating side chains in polymer donors would contribute to a better understanding of this kind of side chain behavior in solution-processed conjugated organic polymers for polymer solar cells. PMID:26754772

  7. Continuous cellularization of calcium phosphate hybrid scaffolds induced by plasma polymer activation.

    PubMed

    Bergemann, Claudia; Cornelsen, Matthias; Quade, Antje; Laube, Thorsten; Schnabelrauch, Matthias; Rebl, Henrike; Weißmann, Volker; Seitz, Hermann; Nebe, Barbara

    2016-02-01

    The generation of hybrid materials based on β-tricalcium phosphate (TCP) and various biodegradable polymers like poly(l-lactide-co-d,l-lactide) (PLA) represents a common approach to overcoming the disadvantages of pure TCP devices. These disadvantages lie in TCP's mechanical properties, such as brittleness. The positive characteristic of PLA - improvement of compressive strength of calcium phosphate scaffolds - is diametrically opposed to its cell attractiveness. Therefore, the objective of this work was to optimize osteoblast migration and cellularization inside a three-dimensionally (3D) printed, PLA polymer stabilized TCP hybrid scaffold by a plasma polymer process depositing amino groups via allylamine. MG-63 osteoblastic cells inside the 10mm hybrid scaffold were dynamically cultivated for 14days in a 3D model system integrated in a perfusion reactor. The whole TCP/PLA hybrid scaffold was continuously colonized due to plasma polymerized allylamine activation inducing the migration potential of osteoblasts.

  8. Continuous cellularization of calcium phosphate hybrid scaffolds induced by plasma polymer activation.

    PubMed

    Bergemann, Claudia; Cornelsen, Matthias; Quade, Antje; Laube, Thorsten; Schnabelrauch, Matthias; Rebl, Henrike; Weißmann, Volker; Seitz, Hermann; Nebe, Barbara

    2016-02-01

    The generation of hybrid materials based on β-tricalcium phosphate (TCP) and various biodegradable polymers like poly(l-lactide-co-d,l-lactide) (PLA) represents a common approach to overcoming the disadvantages of pure TCP devices. These disadvantages lie in TCP's mechanical properties, such as brittleness. The positive characteristic of PLA - improvement of compressive strength of calcium phosphate scaffolds - is diametrically opposed to its cell attractiveness. Therefore, the objective of this work was to optimize osteoblast migration and cellularization inside a three-dimensionally (3D) printed, PLA polymer stabilized TCP hybrid scaffold by a plasma polymer process depositing amino groups via allylamine. MG-63 osteoblastic cells inside the 10mm hybrid scaffold were dynamically cultivated for 14days in a 3D model system integrated in a perfusion reactor. The whole TCP/PLA hybrid scaffold was continuously colonized due to plasma polymerized allylamine activation inducing the migration potential of osteoblasts. PMID:26652403

  9. Free radical generation and concentration in a plasma polymer: the effect of aromaticity.

    PubMed

    Ershov, Sergey; Khelifa, Farid; Lemaur, Vincent; Cornil, Jérôme; Cossement, Damien; Habibi, Youssef; Dubois, Philippe; Snyders, Rony

    2014-08-13

    Plasma polymer films (PPF) have increasing applications in many fields due to the unique combination of properties of this class of materials. Among notable features arising from the specifics of plasma polymerization synthesis, a high surface reactivity can be advantageously used when exploited carefully. It is related to the presence of free radicals generated during the deposition process through manifold molecular bond scissions in the energetic plasma environment. In ambient atmosphere, these radicals undergo autoxidation reactions resulting in undesired polymer aging. However, when the reactivity of surface radicals is preserved and they are put in direct contact with a chemical group of interest, a specific surface functionalization or grafting of polymeric chains can be achieved. Therefore, the control of the surface free radical density of a plasma polymer is crucially important for a successful grafting. The present investigation focuses on the influence of the hydrocarbon precursor type, aromatic vs aliphatic, on the generation and concentration of free radicals on the surface of the PPF. Benzene and cyclohexane were chosen as model precursors. First, in situ FTIR analysis of the plasma phase supplemented by density functional theory calculations allowed the main fragmentation routes of precursor molecules in the discharge to be identified as a function of energy input. Using nitric oxide (NO) chemical labeling in combination with X-ray photoelectron spectroscopy analysis, a quantitative evaluation of concentration of surface free radicals as a function of input power has been assessed for both precursors. Different evolutions of the surface free radical density for the benzene- and cyclohexane-based PPF, namely, a continuous increase versus stabilization to a plateau, are attributed to different plasma polymerization mechanisms and resulting structures as illustrated by PPF characterization findings. The control of surface free radical density can be

  10. Organic-Inorganic Thermoelectrics from Single Monomers to Polymer Devices

    NASA Astrophysics Data System (ADS)

    Chang, William Bee

    Waste heat recovery from the human body provides opportunities to power electronics with a source that is cheap and readily available. Thermoelectrics utilize the Seebeck effect to recover useable electrical energy from this waste heat, but are limited due to material parameters being inversely coupled in the bulk. We investigate the role of novel physics at interfaces in order to develop new fundamental understanding of thermoelectrics. The goal is to discover systems where the Seebeck coefficient and the electrical conductivity are not inversely correlated. We investigate thermoelectric transport in organic-organic systems such as scanning tunneling microscope molecular break junctions on the nanoscale, gold nanocrystal arrays on the mesoscale and polymeric ion and mixed conductors at the macroscale. The STM molecular junctions studied in this work can provide design rules to positively couple the Seebeck coefficient and the electrical conductance. Since STM molecular junctions are one-dimensional systems, by minimizing the gap between the molecular orbital energy level and the electrode Fermi energy, the power factor S2? can be optimized. I built a toolbox of chemical structures by first understanding the role of the interface coupling to alkylthiol binding groups of thiophene-based molecules. With this understanding, I designed small molecules based on the monomer unit of donor-acceptor polymers and other conductive polymers. Molecules with very high HOMO levels or low LUMO levels were studied, and the corresponding energy levels were examined using spectroscopic techniques. I then present our work on scaling these molecular junctions to the macroscale using ligand-exchanged gold nanocrystal arrays. Beginning with a model system of alkanethiols and alkanedithiols, I show that the electrical conductivity scales with ligand length exactly as observed in single molecule junctions, and the Seebeck coefficient follows a similar trend. By showing that gold

  11. Rapid carbon nanotubes suspension in organic solvents using organosilicon polymers.

    PubMed

    Dalcanale, Federico; Grossenbacher, Jonas; Blugan, Gurdial; Gullo, Maurizio R; Brugger, Jürgen; Tevaearai, Hendrik; Graule, Thomas; Kuebler, Jakob

    2016-05-15

    A strategy for a simple dispersion of commercial multi-walled carbon nanotubes (MWCNTs) using two organosilicones, polycarbosilane SMP10 and polysilazane Ceraset PSZ20, in organic solvents such as cyclohexane, tetrahydrofuran (THF), m-xylene and chloroform is presented. In just a few minutes the combined action of sonication and the presence of Pt(0) catalyst is sufficient to obtain a homogeneous suspension, thanks to the rapid hydrosilylation reaction between SiH groups of the polymer and the CNT sidewall. The as-produced suspensions have a particle size distribution <1μm and remain unchanged after several months. A maximum of 0.47 and 0.50mg/ml was achieved, respectively, for Ceraset in THF and SMP10 in chloroform. Possible applications as polymeric and ceramic thin films or aerogels are presented. PMID:26939076

  12. 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.

  13. Communication Support for the U. S. Burning Plasma Organization

    SciTech Connect

    Hegna, Chris

    2014-02-05

    The role of this DOE grant was to provide administrative and software support for the U. S. Burning Plasma Organization (USBPO). The USBPO is a grassroots organization of fusion plasma scientists that concentrates broadly on issues of interest in burning plasma physics in general with a particular emphasis on the needs of the ITER program. The particular role of this grant was to provide support of the communication needs of the USBPO primarily through the administration and maintenance of the USBPO server, the public USBPO website, e-mail lists and numerous members-only discussion forums and mail lists.

  14. Hemocompatible Poly(ethylene terephthalate) Polymer Modified via Reactive Plasma Treatment

    NASA Astrophysics Data System (ADS)

    Cvelbar, Uroš; Junkar, Ita; Modic, Martina

    2011-08-01

    In this paper we present the fabrication of micro- and nanostructure poly(ethylene terephthalate) (PET) polymer surfaces used for as synthetic vascular grafts and their hemocompatible response to plasma-treated surfaces. The surface modification of PET polymer was performed using radio frequency (RF) weakly ionized and highly dissociated oxygen or nitrogen plasma. The surface of the PET polymer was modified to enable the improved proliferation of endothelial cells. In addition to biological experiments performed in vitro by assessing the number of attached cells by tetrazolium compound (MTS)-based cell proliferation assay, we also analyzed the chemical modification of plasma-treated surfaces by X-ray photoelectron spectroscopy (XPS), while the changes in morphology and surface roughness were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. Our results indicate that surface treatment with both oxygen and nitrogen plasma improved the proliferation of endothelial cells, which increased with treatment time by 15 to 30%. This phenomenon was explained by the creation of new functional groups and the modification of surface morphology, which promotes the adhesion of endothelial cells.

  15. Electric Transport Phenomena of Nanocomposite Organic Polymer Thin Films

    NASA Astrophysics Data System (ADS)

    Jira, Nicholas C.; Sabirianov, Ildar; Ilie, Carolina C.

    We discuss herein the nanocomposite organic thin film diodes for the use of plasmonic solar cells. This experimental work follows the theoretical calculations done for plasmonic solar cells using the MNPBEM toolbox for MatLab. These calculations include dispersion curves and amount of light scattering cross sections for different metallic nanoparticles. This study gives us clear ideas on what to expect from different metals, allowing us to make the best choice on what to use to obtain the best results. One specific technique for light trapping in thin films solar cells utilizes metal nanoparticles on the surface of the semiconductor. The characteristics of the metal, semiconductor interface allows for light to be guided in between them causing it to be scattered, allowing for more chances of absorption. The samples were fabricated using organic thin films made from polymers and metallic nanoparticles, more specifically Poly(1-vinylpyrrolidone-co-2-dimethylaminoethyl methacrylate) copolymer and silver or gold nanoparticles. The two fabrication methods applied include spin coating and Langmuir-Blodgett technique. The transport properties are obtained by analyzing the I-V curves. We will also discuss the resistance, resistivity, conductance, density of charge carriers. SUNY Oswego SCAC Grant.

  16. Optical Properties of Polymers Relevant to Secondary Organic Aerosols

    NASA Astrophysics Data System (ADS)

    Marrero-Ortiz, W.; Gomez-Hernandez, M. E.; Xu, W.; Guo, S.; Zhang, R.

    2014-12-01

    Atmospheric aerosols play a critical role in climate directly by scattering and absorbing solar radiation and indirectly by modifying the cloud formation. Currently, the direct and indirect effects of aerosols represent the largest uncertainty in climate predictions models. Some aerosols are directly emitted, but the majority are formed in the atmosphere by the oxidation of gaseous precursors. However, the formation of aerosols at the molecular level is not fully characterized. Certain category of secondary organic aerosols (SOA), which represent a significant fraction of the total aerosol burden, can be light-absorbing, also known as brown carbon. However, the overall contribution of SOA to the brown carbon and the related climate forcing is poorly understood. Such incomplete understanding is due in part to the chemical complexity of SOA and the lack of knowledge regarding SOA formation, transformation, and optical properties. Based on previous laboratory experiments, field measurements, and modeling studies, it has been suggested that the polymers and oligomers play an important role in the SOA formation. Atmospheric polymers could be produced by the hydration or heterogeneous reactions of epoxides and small α-dicarbonyls. Their aqueous chemistry products have been shown to give light-absorbing and high molecular weight oligomeric species, which increase the SOA mass production and alter the direct and indirect effect of aerosols. In this paper, the aerosol chemistry of small α-dicarbonyl compounds with amines is investigated and the associated optical properties are measured using spectroscopic techniques. The differences between primary, secondary and tertiary amines with glyoxal and methylglyoxal are evaluated in terms of SOA browning efficiency. Atmospheric implications of our present work for understanding the formation of light-absorbing SOA will be presented, particularly in terms of the product distribution of light-absorbing SOA formed by aqueous phase

  17. Thiophene-based oligomers, polymers and dendrimers for organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Zhang, Yong

    Demand for inexpensive renewable energy sources has stimulated new approaches for the production of efficient, low cost photovoltaic (PV) solar cell devices. This thesis research has focused on developing thiophene-based oligomers, polymers and dendrimers for this purpose. The key results are summarized as follows: First, three fully characterized polynorbornenes with electronically active pendant oligothiophene side chains have been synthesized and incorporated as active electronic components into single-layer photovoltaic cells. The device tests along with the electrochemical experiments demonstrate that incorporating chemically stable end-groups on the oligothiophene unit is responsible for the improvement of operation stability under ambient conditions. Second, in-situ surface-initiated polymerization of thiophene inside nanoporous networks has been realized. The resulting organic-inorganic hybrids with polythiophene covalently bound inside nanopores can achieve better interface contact, larger surface coverage and more complete filling of the pores. These result in more efficient photoinjection of electrons into the conduction band of nanocrystalline TiO2 than an analogous nanoporous structure infiltrated by polymer synthesized outside the network. The last part of this thesis covers the synthesis and characterization of a new series of semi-flexible oligothiophene-based dendrimers, which show pronounced solvatochromic and thermochromic properties. Microscopic fluorescence investigation of such surface adhered dendrimers provides the evidence that the intramolecular interactions inside these dendritic structures mainly account for the origin of the morphology-related chromism properties. This architecture is promising to make processable light harvesting structures having scaffolded donors covalently integrated with acceptors such as fullerenes in order to fabricate photovoltaics where phase segregation is suppressed.

  18. Degradation of organic fibers in radio frequency plasma

    SciTech Connect

    Finch, J.F.; Poulsen, G.G.; Pitt, W.G. )

    1992-01-01

    Plasma processing can be used to increase adhesion of organic fibers in composite materials, but prolonged exposure can also degrade the fibers, counteracting any adhesive gains. This study investigated the safe upper bounds of plasma processing on four common organic reinforcing fibers: Kevlar 49, Spectra 900, Dacron and Nylon 6. The possible causes of fiber degradation during plasma processing were also examined. Two tests were designed to evaluate fiber tensile strength during and after prolonged exposure to an argon plasma. The first of these tests was a dynamic processing tensile test in which filaments were loaded and exposed to plasma until they failed. The other was a post processing tensile test in which exposed filaments were tensile tested at ambient conditions. These studies determined that all the fibers were adversely affected by the plasma treatment. The degree of degradation was dependent upon the type of fiber, fiber loading, plasma power, and exposure time. The failure of Dacron and Kevlar during plasma processing was dependent upon the applied load. These fibers also showed significant reduction in diameter at failure. In the same type of test the Spectra and Nylon showed no dependency upon load and appeared to fail by melting.

  19. Self-operated blood plasma separation using micropump in polymer-based microfluidic device

    NASA Astrophysics Data System (ADS)

    Jang, Won Ick; Chung, Kwang Hyo; Pyo, Hyeon Bong; Park, Seon Hee

    2006-12-01

    The blood is one of the best indicators of health because blood circulates all body tissues and collects information. The COC(Cyclo Olefin Copolymer) has better various properties than PMMA(Polymethy Mechacrylate) and PC(Polycarbonate) that are widely used in biotechnology field. This paper presents a new method of plasma separation on the COC in terms of surface modification for the development of a disposable protein chip. The blood plasma separation device was composed of a whole blood inlet, microchannel with filtration region of micropillars, micropump with microheater, and a blood cell outlet. Micropump with microheater was designed by ANSYS and flow model in the microchannel was designed by CFD-ACE + simulators. We successfully fabricated a polymer based microfluidic device for blood plasma separation by MEMS(Micro Electro Mechanical System) technology. By using this device, cell-free plasma was successfully obtained through the filtration from a drop of whole blood without external force of a syringe pump.

  20. Self-organized polymer aggregates with a biomimetic hierarchical structure and its superhydrophobic effect.

    PubMed

    Zhao, Ning; Zhang, Xiao-Yan; Li, Yan-Fang; Lu, Xiao-Ying; Sheng, Si-Lu; Zhang, Xiao-Li; Xu, Jian

    2007-01-01

    Nature always gives us inspirations to fabricate functional materials by mimicking the structure design of biomaterials. In this article, we report that polymeric aggregates with morphology similar to the papilla on lotus leaf can be self-organized in the polymer solution by adding 16 wt% water into 5 mg/ml polycarbonate solution in N,N'-dimethylformamide. The hierarchically structured aggregates at micro- and nano-scale alone show superhydrophobic effect without the need of modification with low surface energy compound. Small amount of liquid can be wrapped by the aggregates to form the so-called liquid marble. Influence of the amount of water added into the solution on the morphology of resultant polymer aggregates was investigated. By using the hierarchical aggregates as the surface building blocks, superhydrophobic coating with a static water contact angle larger than 160 degrees and sliding angle less than 5 degrees (for a water drop of 5 microl) was formed. Other solutions, like acid, basic and blood plasma are also repelled on the coating.

  1. Scanning probe microscopy for the analysis of composite Ti/hydrocarbon plasma polymer thin films

    NASA Astrophysics Data System (ADS)

    Choukourov, A.; Grinevich, A.; Slavinska, D.; Biederman, H.; Saito, N.; Takai, O.

    2008-03-01

    Composite Ti/hydrocarbon plasma polymer films with different Ti concentration were deposited on silicon by dc magnetron sputtering of titanium in an atmosphere of argon and hexane. As measured by Kelvin force microscopy and visco-elastic atomic force microscopy, respectively, surface potential and hardness increase with increasing Ti content. Adhesion force to silicon and to fibrinogen molecules was stronger for the Ti-rich films as evaluated from the AFM force-distance curves. Fibrinogen forms a very soft layer on these composites with part of the protein molecules embedded in the outermost region of the plasma polymer. An increase of the surface charge due to fibrinogen adsorption has been observed and attributed to positively charged αC domains of fibrinogen molecule.

  2. Chemical anchoring of organic conducting polymers to semiconducting surfaces

    DOEpatents

    Frank, A.J.; Honda, K.

    1984-01-01

    According to the present invention, an improved method of coating electrodes with conductive polymer films and/or preselected catalysts is provided. The charge conductive polymer is covalently or coordinatively attached to the electrode surface to strengthen the adhesion characteristics of the polymer to the electrode surface or to improve charge conductive properties between the conductive polymer and the electrode surface. Covalent or coordinative attachment is achieved by a number of alternative methods including covalently or coordinatively attaching the desired monomer to the electrode by means of a suitable coupling reagent and, thereafter, electrochemically polymerizing the monomer in situ.

  3. Chemical anchoring of organic conducting polymers to semiconducting surfaces

    DOEpatents

    Frank, Arthur J.; Honda, Kenji

    1984-01-01

    According to the present invention, an improved method of coating electrodes with conductive polymer films and/or preselected catalysts is provided. The charge-conductive polymer is covalently or coordinatively attached to the electrode surface to strengthen the adhesion characteristics of the polymer to the electrode surface or to improve charge-conductive properties between the conductive polymer and the electrode surface. Covalent or coordinative attachment is achieved by a number of alternative methods including covalently or coordinatively attaching the desired monomer to the electrode by means of a suitable coupling reagent and, thereafter, electrochemically polymerizing the monomer in situ.

  4. Densification of functional plasma polymers by momentum transfer during film growth

    SciTech Connect

    Hegemann, Dirk; Koerner, Enrico; Blanchard, Noemi; Drabik, Martin; Guimond, Sebastien

    2012-11-19

    Functional plasma polymers were deposited from pure ethylene discharges and with the addition of carbon dioxide or ammonia. The incorporation of oxygen and nitrogen-containing functional groups depends on the fragmentation in the gas phase as well as on the densification during film growth. While a minimum energy per deposited carbon atom is required for cross-linking, the densification and accompanying reduction of functional group incorporation was found to scale linearly with momentum transfer through ion bombardment during film growth.

  5. Study of Organosilicon Plasma Polymer Used in Composite Layers with Biomedical Application

    NASA Astrophysics Data System (ADS)

    Radeva, E.; Pramatarova, L.; Pecheva, E.; Hikov, T.; Iacob, E.; Vanzetti, L.; Dimitrova, R.; Krasteva, N.; Spassov, T.; Fingarova, D.

    2010-01-01

    In this work we study the ability of plasma polymer (PP) films obtained from hexamethyldisiloxane (HMDS) on silica glass (SG) to induce hydroxyapatite (HA)-based composite layers from a mixture of simulated body fluid (SBF) and clear solution of detonation nanodiamond (DND) by a biomimetic process. The grown composites (PPHMDS/HADND) were studied by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and Rutherford backscattering (RBS) techniques. FTIR spectra of the PPHMDS indicated diminishing of the polymer characteristic bands when the polymer is immersed in DND clear solution. Furthermore, after sample immersion in the SBF-DND mixture, the FTIR spectra showed the presence of carbonate-containing HA through the characteristic vibration modes of P-O in the phosphate group and C-O in the carbonate group. The formation of HA layers, rich in silica and/or carbon was confirmed by RBS and SEM. The cell viability measured after 7 days on the polymer surface is more then 95% for all samples. The results show that the PPHMDS is promising as a substrate for growing HA/DND layers and that the materials obtained are biocompatible. The variations of plasma polymerization conditions and modification of the composite layers will aid in using such materials for biomedical applications.

  6. Study of Organosilicon Plasma Polymer Used in Composite Layers with Biomedical Application

    SciTech Connect

    Radeva, E.; Pramatarova, L.; Pecheva, E.; Hikov, T.; Fingarova, D.; Iacob, E.; Vanzetti, L.; Dimitrova, R.; Krasteva, N.; Spassov, T.

    2010-01-21

    In this work we study the ability of plasma polymer (PP) films obtained from hexamethyldisiloxane (HMDS) on silica glass (SG) to induce hydroxyapatite (HA)-based composite layers from a mixture of simulated body fluid (SBF) and clear solution of detonation nanodiamond (DND) by a biomimetic process. The grown composites (PPHMDS/HADND) were studied by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and Rutherford backscattering (RBS) techniques. FTIR spectra of the PPHMDS indicated diminishing of the polymer characteristic bands when the polymer is immersed in DND clear solution. Furthermore, after sample immersion in the SBF-DND mixture, the FTIR spectra showed the presence of carbonate-containing HA through the characteristic vibration modes of P-O in the phosphate group and C-O in the carbonate group. The formation of HA layers, rich in silica and/or carbon was confirmed by RBS and SEM. The cell viability measured after 7 days on the polymer surface is more then 95% for all samples. The results show that the PPHMDS is promising as a substrate for growing HA/DND layers and that the materials obtained are biocompatible. The variations of plasma polymerization conditions and modification of the composite layers will aid in using such materials for biomedical applications.

  7. Polymer nanofibers: preserving nanomorphology in ternary blend organic photovoltaics.

    PubMed

    Salim, Teddy; Lek, Jun Yan; Bräuer, Björn; Fichou, Denis; Lam, Yeng Ming

    2014-11-21

    The morphology of donor-acceptor blends holds the key to good performance through the balancing of good exciton dissociation efficiency and interconnectivity for good charge collection. In this work, the good morphology is preserved in ternary blend systems through the use of poly(3-hexylthiophene) (P3HT) nanofibers. The iridium(III)-based metal complex is incorporated in P3HT-PCBM blends as a triplet exciton sensitizer in the bulk heterojunction (BHJ) organic photovoltaics (OPV). The devices using triplet-sensitized ternary blends of P3HT experience a significant degradation in performance, a tendency further aggravated by thermal treatment. This is due to disruption in the morphology thus affecting charge generation and collection. In order to overcome these morphological issues and to circumvent the restriction due to the crystallization of the polymers, here we demonstrate the use of pre-assembled nanofibers in these ternary blends. The concept of stabilizing the nanomorphology of the blend material through the use of nanofibers can also be applied to other ternary systems.

  8. Plasma - enhanced dispersion of metal and ceramic nanoparticles in polymer nanocomposite films

    NASA Astrophysics Data System (ADS)

    Maguire, Paul; Liu, Yazi; Askari, Sadegh; Patel, Jenish; Macia-Montero, Manuel; Mitra, Somak; Zhang, Richao; Sun, Dan; Mariotti, Davide

    2015-09-01

    In this work we demonstrate a facile method to synthesize a nanoparticle/PEDOT:PSS hybrid nanocomposite material in aqueous solution through atmospheric pressure direct current (DC) plasma processing at room temperature. Both metal (Au) and ceramic (TiO2) nanoparticle composite films have been fabricated. Nanoparticle dispersion is enhanced considerable and remains stable. TiO2/polymer hybrid nanoparticles with a distinct core shell structure have been obtained. Increased nanoparticle/PEDOT:PSS nanocomposite electrical conductivity has been observed. The improvement in nanocomposite properties is due to the enhanced dispersion and stability in liquid polymer of microplasma processed Au or TiO2 nanoparticles. Both plasma induced surface charge and nanoparticle surface termination with specific plasma chemical species are thought to provide an enhanced barrier to nanoparticle agglomeration and promote nanoparticle-polymer bonding. This is expected to have a significant benefit in materials processing with inorganic nanoparticles for applications in energy storage, photocatalysis and biomedical sensors. Engineering and Physical Sciences Research Council (EPSRC: EP/K006088/1, EP/K006142, Nos. EP/K022237/1).

  9. Plasma Interaction with Organic Molecules in Liquid as Fundamental Processes in Plasma Medicine.

    PubMed

    Takenaka, Kosuke; Miyazaki, Atsushi; Abe, Hiroya; Uchida, Giichiro; Setsuhara, Yuichi

    2015-03-01

    Investigation of plasma-organic materials interaction in aqueous solution with atmospheric pressure plasmas have been carried out. Degradation of methylene blue (MB) in aqueous solution via atmospheric pressure He plasma exposure through gas/liquid interface have been investigated. The optical emission spectrum shows considerable emissions of He lines and the emission of O, OH and N radicals attributed to dissociation of water (H2O) and air has been confirmed. Structure variation of MB in solution treated with the atmospheric-pressure He plasma has been measured by Fourier transform infrared spectroscopy (FT-IR). The results obtained from FT-IR analysis show degradation of MB in solution treated with the atmospheric-pressure He plasma. The pH effect of MB degradation was investigated using controlled pH solutions by an ultraviolet-visible (UV-Vis) spectroscopy and FT-IR. The results show no effect of MB degradation on pH. The results exhibit that the atmospheric pressure plasmas exposure has made it possible to degrade organic materials in solution due to irradiated radicals from plasma through plasma/liquid interface. PMID:26413629

  10. Polymer chain organization in tensile-stretched poly(ethylene oxide)-based polymer electrolytes

    PubMed Central

    Burba, Christopher M.; Woods, Lauren; Millar, Sarah Y.; Pallie, Jonathan

    2011-01-01

    Polymer chain orientation in tensile-stretched poly(ethylene oxide)-lithium trifluoromethanesulfonate polymer electrolytes are investigated with polarized infrared spectroscopy as a function of the degree of strain and salt composition (ether oxygen atom to lithium ion ratios of 20:1, 15:1, and 10:1). The 1359 and 1352 cm-1 bands are used to probe the crystalline PEO and P(EO)3LiCF3SO3 domains, respectively, allowing a direct comparison of chain orientation for the two phases. Two-dimensional correlation FT-IR spectroscopy indicates that the two crystalline domains align at the same rate as the polymer electrolytes are stretched. Quantitative measurements of polymer chain orientation obtained through dichroic infrared spectroscopy show that chain orientation predominantly occurs between strain values of 150% and 250%, regardless of salt composition investigated. There are few changes in chain orientation for either phase when the films are further elongated to a strain of 300%; however, the PEO domains are slightly more oriented at the high strain values. The spectroscopic data are consistent with stretching-induced melt-recrystallization of the unoriented crystalline domains in the solution-cast polymer films. Stretching the films pulls polymer chains from the crystalline domains, which subsequently recrystallize with the polymer helices parallel to the stretch direction. If lithium ion conduction in crystalline polymer electrolytes is viewed as consisting of two major components (facile intra-chain lithium ion conduction and slow helix-to-helix inter-grain hopping), then alignment of the polymer helices will affect the ion conduction pathways for these materials by reducing the number of inter-grain hops required to migrate through the polymer electrolyte. PMID:22184475

  11. Polymer chain organization in tensile-stretched poly(ethylene oxide)-based polymer electrolytes.

    PubMed

    Burba, Christopher M; Woods, Lauren; Millar, Sarah Y; Pallie, Jonathan

    2011-12-15

    Polymer chain orientation in tensile-stretched poly(ethylene oxide)-lithium trifluoromethanesulfonate polymer electrolytes are investigated with polarized infrared spectroscopy as a function of the degree of strain and salt composition (ether oxygen atom to lithium ion ratios of 20:1, 15:1, and 10:1). The 1359 and 1352 cm(-1) bands are used to probe the crystalline PEO and P(EO)(3)LiCF(3)SO(3) domains, respectively, allowing a direct comparison of chain orientation for the two phases. Two-dimensional correlation FT-IR spectroscopy indicates that the two crystalline domains align at the same rate as the polymer electrolytes are stretched. Quantitative measurements of polymer chain orientation obtained through dichroic infrared spectroscopy show that chain orientation predominantly occurs between strain values of 150% and 250%, regardless of salt composition investigated. There are few changes in chain orientation for either phase when the films are further elongated to a strain of 300%; however, the PEO domains are slightly more oriented at the high strain values. The spectroscopic data are consistent with stretching-induced melt-recrystallization of the unoriented crystalline domains in the solution-cast polymer films. Stretching the films pulls polymer chains from the crystalline domains, which subsequently recrystallize with the polymer helices parallel to the stretch direction. If lithium ion conduction in crystalline polymer electrolytes is viewed as consisting of two major components (facile intra-chain lithium ion conduction and slow helix-to-helix inter-grain hopping), then alignment of the polymer helices will affect the ion conduction pathways for these materials by reducing the number of inter-grain hops required to migrate through the polymer electrolyte.

  12. Surface temperature: A key parameter to control the propanethiol plasma polymer chemistry

    SciTech Connect

    Thiry, Damien Aparicio, Francisco J.; Laha, Priya; Terryn, Herman; Snyders, Rony

    2014-09-01

    In this work, the influence of the substrate temperature (T{sub s}) on the chemical composition of propanethiol plasma polymers was investigated for a given set of plasma conditions. In a first study, a decrease in the atomic sulfur content (at. %S) with the deposition time (t{sub d}) was observed. This behavior is explained by the heating of the growing film during deposition process, limiting the incorporation of stable sulfur-based molecules produced in the plasma. Experiments carried out by controlling the substrate temperature support this hypothesis. On the other hand, an empirical law relating the T{sub s} and the at. %S was established. This allows for the formation of gradient layer presenting a heterogeneous chemical composition along the thickness, as determined by depth profile analysis combining X-ray photoelectron spectroscopy and C{sub 60} ion gun sputtering. The experimental data fit with the one predicted from our empiric description. The whole set of our results provide new insights in the relationship between the substrate temperature and the sulfur content in sulfur-based plasma polymers, essential for future developments.

  13. 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.

  14. 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.

  15. Chemical sensing system using plasma polymer films and pattern recognition algorithm

    SciTech Connect

    Nakamura, M.; Sugimoto, I.; Kuwano, H.

    1994-05-01

    A chemical sensing system using a sensor array with sensitive but durable plasma polymer films is developed. Plasma polymer films have unsaturated bonds and radical sites which cause several unique characteristics. These films contain high concentrations of unsaturated bonds and radical sites, which act as interactive sites. These sites, scattered throughout an inert fluorocarbon framework, are believed to induce specific interactions with small molecules through pi and spin interactions. We have tried to apply our knowledge of these interactions to molecular recognition. For sensing small molecules, these films are deposited on both sides of an AT-cut quartz crystal microbalance (QCM) with a resonant frequency of 9 MHz by radio-frequency (RF) sputtering of polymers such as polychlorotrifluoroethylene. The QCM is connected to an oscillator circuit and its resonant shift is proportional to the mass of the adsorbed molecules. The affinity of plasma polymer films can be shifted by changing sputtering conditions such as the target materials, temperature, or RF power. The chemical sensing system studied here uses a sensor array having modified films with various sensitivities. Because the sensor films have an affinity for several kinds of gases, a pattern recognition algorithm is needed to discern unique gas information from sensors that have overlapping selectivities. The equilibrium mass of adsorbed gas and a time constant are first extracted from the time-dependent sensor outputs, which show that the adsorption process resembles Langmuir adsorption, and then the parameters are mapped to a classification space and used for classification. The addition of a time constant increases the selectivity of our sensor system for single-gas analysis and mixture analysis. 12 refs.

  16. Influence of artificially accelerated ageing on the adhesive joint of plasma treated polymer materials

    NASA Astrophysics Data System (ADS)

    Lehocký, M.; Lapčik, L.; Dlabaja, R.; Rachünek, L.; Stoch, J.

    2004-03-01

    An influence of simulated ageing on the adhesive joint of plasma treated polyethylene (PE) and polypropylene (PP) was tested. Plasma surface treatment was performed in the rf-plasma reactor operating at 13,56 MHz. The simulated ageing of prepared specimens for following tensile testing was carried out under conditions given by Volkswagen standard P-VW 1200. Temperature of ageing was regularly oscillating between -40°C and 80°C (relative humidity 80%) for required time. The mechanical tensile properties of adhesive joint were measured according to the standard ISO 527. Surface analysis of treated polymer substrates was characterized by XPS measurement. The observation of surface structure and morphology was obtained using SEM. We used convenient cyanoacrylate adhesive Loctite E 406 for PE and PP joints. Tested adhesive joints were prepared in compliance with the standard ISO 4587.

  17. Evaluation of Assam Bora rice starch as plasma volume expander by polymer analysis.

    PubMed

    Bhattacharya, Ashokanshu; Akhter, Sohail; Shahnawaz, Sheikh; Siddiqui, Abdul Wadood; Ahmad, Mohammad Zaki

    2010-12-01

    Water soluble polysaccharides are currently finding increasing use as a basis material for plasma volume expander. In clinical setting it is desirable to have a precise knowledge of steric and chemical structure, since these affect the pharmacokinetics and pharmacology of plasma volume expander. Branch component of starch amylopectin is very similar in structure to glycogen, the reserve polysaccharide of animal and therefore is liable to be compatible with body tissue. The knowledge of weight average molecular mass, degree of branching, osmotic pressure and coil dimension are essential, since low molecular mass do not have desirable effect and large molar mass have undesirable effect. Assam Bora rice starch was characterized by polymer analysis for use as plasma volume expander. Characterization involves the determination of FTIR spectra, degree of branching by H1 NMR, osmotic pressure by internal measurement technique, establishment of Mark-Houwink relationship and determination of Molecular weight - viscosity relationship. PMID:20950261

  18. Metallated porphyrin based porous organic polymers as efficient electrocatalysts

    NASA Astrophysics Data System (ADS)

    Lu, Guolong; Zhu, Youlong; Xu, Kongliang; Jin, Yinghua; Ren, Zhiyong Jason; Liu, Zhenning; Zhang, Wei

    2015-10-01

    Developing efficient, stable and low-cost catalysts for Oxygen Reduction Reaction (ORR) is of great significance to many emerging technologies including fuel cells and metal-air batteries. Herein, we report the development of a cobalt(ii) porphyrin based porous organic polymer (CoPOP) and its pyrolyzed derivatives as highly active ORR catalysts. The as-synthesized CoPOP exhibits high porosity and excellent catalytic performance stability, retaining ~100% constant ORR current over 50 000 s in both alkaline and acidic media. Pyrolysis of CoPOP at various temperatures (600 °C, 800 °C, and 1000 °C) yields the materials consisting of graphitic carbon layers and cobalt nanoparticles, which show greatly enhanced catalytic activity compared to the as-synthesized CoPOP. Among them, CoPOP-800/C pyrolyzed at 800 °C shows the highest specific surface area and ORR activity, displaying the most positive half-wave potential (0.825 V vs. RHE) and the largest limited diffusion current density (5.35 mA cm-2) in an alkaline medium, which are comparable to those of commercial Pt/C (20 wt%) (half-wave potential 0.829 V vs. RHE, limited diffusion current density 5.10 mA cm-2). RDE and RRDE experiments indicate that CoPOP-800/C directly reduces molecular oxygen to water through a 4-e- pathway in both alkaline and acidic media. More importantly, CoPOP-800/C exhibits excellent durability and methanol-tolerance under acidic and alkaline conditions, which surpass the Pt/C (20 wt%) system.Developing efficient, stable and low-cost catalysts for Oxygen Reduction Reaction (ORR) is of great significance to many emerging technologies including fuel cells and metal-air batteries. Herein, we report the development of a cobalt(ii) porphyrin based porous organic polymer (CoPOP) and its pyrolyzed derivatives as highly active ORR catalysts. The as-synthesized CoPOP exhibits high porosity and excellent catalytic performance stability, retaining ~100% constant ORR current over 50 000 s in both

  19. Metallated porphyrin based porous organic polymers as efficient electrocatalysts.

    PubMed

    Lu, Guolong; Zhu, Youlong; Xu, Kongliang; Jin, Yinghua; Ren, Zhiyong Jason; Liu, Zhenning; Zhang, Wei

    2015-11-21

    Developing efficient, stable and low-cost catalysts for Oxygen Reduction Reaction (ORR) is of great significance to many emerging technologies including fuel cells and metal-air batteries. Herein, we report the development of a cobalt(II) porphyrin based porous organic polymer (CoPOP) and its pyrolyzed derivatives as highly active ORR catalysts. The as-synthesized CoPOP exhibits high porosity and excellent catalytic performance stability, retaining ∼100% constant ORR current over 50,000 s in both alkaline and acidic media. Pyrolysis of CoPOP at various temperatures (600 °C, 800 °C, and 1000 °C) yields the materials consisting of graphitic carbon layers and cobalt nanoparticles, which show greatly enhanced catalytic activity compared to the as-synthesized CoPOP. Among them, CoPOP-800/C pyrolyzed at 800 °C shows the highest specific surface area and ORR activity, displaying the most positive half-wave potential (0.825 V vs. RHE) and the largest limited diffusion current density (5.35 mA cm(-2)) in an alkaline medium, which are comparable to those of commercial Pt/C (20 wt%) (half-wave potential 0.829 V vs. RHE, limited diffusion current density 5.10 mA cm(-2)). RDE and RRDE experiments indicate that CoPOP-800/C directly reduces molecular oxygen to water through a 4-e(-) pathway in both alkaline and acidic media. More importantly, CoPOP-800/C exhibits excellent durability and methanol-tolerance under acidic and alkaline conditions, which surpass the Pt/C (20 wt%) system. PMID:26486413

  20. A NOVEL HYDROPHILIC POLYMER MEMBRANE FOR THE DEHYDRATION OF ORGANIC SOLVENTS

    EPA Science Inventory

    Novel hydrophilic polymer membranes based on polyallylamine ydrochloride- polyvinylalcohol are developed. The high selectivity and flux characteristics of these membranes for the dehydration of organic solvents are evaluated using pervaporation technology and are found to be ver...

  1. There Is No Simple Model of the Plasma Membrane Organization

    PubMed Central

    Bernardino de la Serna, Jorge; Schütz, Gerhard J.; Eggeling, Christian; Cebecauer, Marek

    2016-01-01

    Ever since technologies enabled the characterization of eukaryotic plasma membranes, heterogeneities in the distributions of its constituents were observed. Over the years this led to the proposal of various models describing the plasma membrane organization such as lipid shells, picket-and-fences, lipid rafts, or protein islands, as addressed in numerous publications and reviews. Instead of emphasizing on one model we in this review give a brief overview over current models and highlight how current experimental work in one or the other way do not support the existence of a single overarching model. Instead, we highlight the vast variety of membrane properties and components, their influences and impacts. We believe that highlighting such controversial discoveries will stimulate unbiased research on plasma membrane organization and functionality, leading to a better understanding of this essential cellular structure. PMID:27747212

  2. Plasma modification of poly(2-heptadecyl-4-vinylthieno[3,4-d]thiazole) low bandgap polymer and its application in solar cells.

    PubMed

    Attri, Pankaj; Bharti, Vishal; Kim, Young Sun; Gaur, Jitender; Chand, Suresh; Kwon, Gi-Chung; Lee, Seung-Hyun; Lee, Weontae; Choi, Eun Ha; Kim, In Tae

    2014-12-28

    For the first time, we here propose a green methodology to modify a low bandgap polymer for highly efficient solar cells using atmospheric pressure plasma jet or soft plasma operating on different feeding gases (air, Ar and N2). The physical properties of the modified polymer were investigated using conductivity measurements, UV-visible spectroscopy, photoluminescence spectroscopy, X-ray photoelectron spectroscopy, cyclic voltammograms, atomic force microscopy, cathodoluminescence and confocal Raman spectroscopy. Further, we examined the variation of the work function of the polymer before and after plasma treatment using a γ-focused ion beam. Additionally, photovoltaic cells based on the plasma-modified polymer having ITO/PEDOT:PSS/PHVTT (with or without plasma modification):PC71BM/LiF/Al configuration were fabricated and then characterized. We found that the power conversion efficiency (PCE) of the plasma-modified polymer increased dramatically as compared to the control polymer (without plasma treatment). PCE of the control polymer was found to be 4.11%, while after air, Ar and N2 gas plasma treatment the polymer showed PCEs of 4.85%, 4.87% and 5.14% respectively. Thus, plasma treatment not only alters the surface properties, but also modifies the bulk properties (changes in HOMO and LUMO bandgap level). Hence, this work provides new dimensions to explore more about plasma and polymer chemistry.

  3. Investigation of plasma-organic materials interaction in aqueous solution with atmospheric pressure plasmas

    NASA Astrophysics Data System (ADS)

    Takenaka, K.; Miyazaki, A.; Setsuhara, Y.

    2014-06-01

    An investigation was carried out into the interaction of an atmospheric pressure plasma with an organic material in an aqueous solution. The degradation of methylene blue (MB) by plasma exposure through the gas/liquid interface was studied. In the optical emission spectrum of the plasma, in addition to strong He emission lines, emissions due to O and OH radicals formed by dissociation of water were present. The change in the absorbance of a MB aqueous solution during plasma exposure was measured using UV-Vis spectroscopy. The absorption peak intensity decreased with plasma exposure time and complete decolorization occurred after 10 min. Since plasma exposure was found to decrease the pH of water, the effect of changes in pH on MB degradation in the absence of a plasma was investigated using solutions with different pH values. However, varying the pH was found to have no influence on MB degradation. The results indicated that MB degradation occurred due to interactions between MB and radicals across the plasma/liquid interface.

  4. Unusual Transformation from a Solvent-Stabilized 1D Coordination Polymer to a Metal-Organic Framework (MOF)-Like Cross-Linked 3D Coordination Polymer.

    PubMed

    Lee, Seung-Chul; Choi, Eun-Young; Lee, Sang-Beom; Kim, Sang-Wook; Kwon, O-Pil

    2015-10-26

    An unusual 1D-to-3D transformation of a coordination polymer based on organic linkers containing highly polar push-pull π-conjugated side chains is reported. The coordination polymers are synthesized from zinc nitrate and an organic linker, namely, 2,5-bis{4-[1-(4-nitrophenyl)pyrrolidin-2-yl]butoxy}terephthalic acid, which possesses highly polar (4-nitrophenyl)pyrrolidine groups, with high dipole moments of about 7 D. The coordination polymers exhibit an unusual transformation from a soluble, solvent-stabilized 1D coordination polymer into an insoluble, metal-organic framework (MOF)-like 3D coordination polymer. The coordination polymer exhibits good film-forming ability, and the MOF-like films are insoluble in conventional organic solvents.

  5. Moisture resistant and anti-reflection optical coatings produced by plasma polymerization of organic compounds

    NASA Technical Reports Server (NTRS)

    Hollahan, J. R.; Wydeven, T.

    1975-01-01

    The need for protective coatings on critical optical surfaces, such as halide crystal windows or lenses used in spectroscopy, has long been recognized. It has been demonstrated that thin, one micron, organic coatings produced by polymerization of flourinated monomers in low temperature gas discharge (plasma) exhibit very high degrees of moisture resistence, e.g., hundreds of hours protection for cesium iodide vs. minutes before degradation sets in for untreated surfaces. The index of refraction of these coatings is intermediate between that of the halide substrate and air, a condition for anti-reflection, another desirable property of optical coatings. Thus, the organic coatings not only offer protection, but improved transmittance as well. The polymer coating is non-absorbing over the range 0.4 to 40 microns with an exception at 8.0 microns, the expected absorption for C-F bonds.

  6. Metal doped fluorocarbon polymer films prepared by plasma polymerization using an RF planar magnetron target

    NASA Astrophysics Data System (ADS)

    Biederman, H.; Holland, L.

    1983-07-01

    Fluorocarbon films have been prepared by plasma polymerization of CF4 using an RF planar magnetron with an aluminium target. More than one order of magnitude higher deposition rate has been achieved in comparison with an r.f. diode system operated under similar conditions of monomer pressure and flow rate and power input. A glow discharge in a CF4[25%]-argon [75%] mixture was used to incorporate aluminium from a target electrode into the polymer films. The foregoing mixture and another based on CF4 [87%]-argon [13%] were used in the RF discharge with a copper target. Some experiments with a gold target and pure CF4 as the inlet gas were also made. The film structure was examined by SEM and TEM and characteristic micrographs are presented here. The composition of the films was estimated from an AES study. The sheet resistivity of the metal/polymer film complexes was determined.

  7. Atmospheric Pressure non-thermal plasmas for surface treatment of polymer films

    NASA Astrophysics Data System (ADS)

    Huang, Hsiao-Feng; Wen, Chun-Hsiang; Wei, Hsiao-Kuan; Kou, Chwung-Shan

    2006-10-01

    Interest has grown over the past few years in applying atmospheric pressure non-thermal plasmas to surface treatment. In this work, we used an asymmetric glow dielectric-barrier discharge (GDBD), at atmospheric pressure in nitrogen, to improve the surface hydrophilicity of three kinds of polymer films, biaxially oriented polypropylene (BOPP), polyimide (PI), and triacetyl cellulose (TAC). This set-up consists of two asymmetric electrodes covered by dielectrics. And to prevent the filamentary discharge occur, the frequency, gas flow rate and uniformity of gas flow distribution should be carefully controlled. The discharge performance is monitored through an oscilloscope, which is connected to a high voltage probe and a current monitor. The physical and chemical properties of polymer surfaces before and after GDBD treatment were analyzed via water contact angle (CA) measurements, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) techniques.

  8. Composite materials obtained by the ion-plasma sputtering of metal compound coatings on polymer films

    NASA Astrophysics Data System (ADS)

    Khlebnikov, Nikolai; Polyakov, Evgenii; Borisov, Sergei; Barashev, Nikolai; Biramov, Emir; Maltceva, Anastasia; Vereshchagin, Artem; Khartov, Stas; Voronin, Anton

    2016-01-01

    In this article, the principle and examples composite materials obtained by deposition of metal compound coatings on polymer film substrates by the ion-plasma sputtering method are presented. A synergistic effect is to obtain the materials with structural properties of the polymer substrate and the surface properties of the metal deposited coatings. The technology of sputtering of TiN coatings of various thicknesses on polyethylene terephthalate films is discussed. The obtained composites are characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and scanning tunneling microscopy (STM) is shown. The examples of application of this method, such as receiving nanocomposite track membranes and flexible transparent electrodes, are considered.

  9. Impact of plasma exposure on organic low-k materials

    NASA Astrophysics Data System (ADS)

    Smirnov, E.; Ferchichi, A. K.; Huffman, C.; Baklanov, M. R.

    2010-02-01

    The impact of different etch plasmas on advanced porous organic low-k material is studied. Several analytical techniques such as Ellipsometric porosimetry (porosity and pore size), Water Contact Angle (hydrophilicity) and FTIR spectroscopy (chemical composition) are used for evaluation. The wafers were exposed in three different chambers (ICP, CCP and μWave) with various gas mixtures. The highest etch rate is obtained in O2/Cl2 and H2/N2 plasma in an inductively coupled plasma (ICP chamber) and the capacitevly coupled plasma (CCP chamber) respectively. Exposure of the low-k films in CCP plasma chamber with C4F8 / CH2F2 / Ar/N2 gas mixture can be used for the further damage prevention, because completely seals the pores. The surface of the sealed films remains hydrophobic (WCA=88°). The He/H2, C4F8/CH2F2/O2/Ar/N2, CF4/CH2F2 gas mixtures in CCP chamber provide partial pore sealing. The measured refractive indices showed no significant change between the damaged and pristine samples, however the plasma exposure in O2/Cl2 shows a tendency of C=O groups formation which may act as further centers of moisture adsorption.

  10. Novel semiconducting polymers: Synthesis, characterization, and their application in organic electronics

    NASA Astrophysics Data System (ADS)

    Hubijar, Emir

    Conjugated polymers have attracted considerable attention as semiconducting materials in recent years due to their versatile electronic and optoelectronic applications. The main promise of conjugated polymers is not just attaining or exceeding the level of performance of silicon technologies but also producing electronic devices at a lower cost and enabling completely new device functionalities such as light weight, large surface area, mechanical flexibility, and optical transparency. Due to their broad potential, conjugated polymers have been incorporated in the wide range of applications, including polymer light-emitting diodes (LEDs), organic field-effect transistors (OFETs), and polymer solar cells (PSCs). Chapter 1 provides general information on conjugated polymers utilized in polymer light-emitting diodes (LEDs), polymer solar cells (PSCs) and organic field effect transistors (OFETs). It also includes brief description and schematic diagrams for each device configuration. Chapter 2 describes the synthesis, characterization and electronic properties of a novel symmetrical sulfone-substituted polyphenylene vinylene (SO 2EH-PPV) for applications in light-emitting devices. The sulfonyl functional group was directly attached to the polymer's backbone to increase the electron affinities of the polymer. The polymer was incorporated into a single layer PLED devices with the configuration of (ITO/ PEDOT:PSS/SO2EH-PPV polymer/Al). Chapter 3 focuses on the synthesis and color tuning of novel poly (fluorenevinylene-co-sulfonylphenylenevinylene) based copolymers for application in light-emitting diodes. New electroluminescent Poly(fluorenevinylene)-co-(sulfonylphenylenevinylene) random copolymers with different monomer feed ratios (PFV-SO2EH 10 and PFV-SO2EH 50) were synthesized via palladium-catalyzed Stille coupling reaction. Single layer stable PLED devices with the configuration of (ITO/PEDOT:PSS/PFV-SO 2EH 10 & PFV-SO2EH 50 polymer/Al) were fabricated exhibiting a

  11. 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.

  12. Nitroxide polymer brushes grafted onto silica nanoparticles as cathodes for organic radical batteries

    NASA Astrophysics Data System (ADS)

    Lin, Hsiao-Chien; Li, Chia-Chen; Lee, Jyh-Tsung

    2011-10-01

    Nitroxide polymer brushes grafted on silica nanoparticles as binder-free cathodes for organic radical batteries have been investigated. Scanning electron microscopy, transmission electron microscopy, infrared spectroscopy and electron spin resonance confirm that the nitroxide polymer brushes are successfully grafted onto silica nanoparticles via surface-initiated atom transfer radical polymerization. The thermogravimetric analysis results indicate that the onset decomposition temperature of these nitroxide polymer brushes is found to be ca. 201 °C. The grafting density of the nitroxide polymer brushes grafted on silica nanoparticles is 0.74-1.01 chains nm-2. The results of the electrochemical quartz crystal microbalance indicate that the non-crosslinking nitroxide polymer brushes prevent the polymer from dissolving into organic electrolytes. Furthermore, the electrochemical results show that the discharge capacity of the polymer brushes is 84.9-111.1 mAh g-1 at 10 C and the cells with the nitroxide polymer brush electrodes have a very good cycle-life performance of 96.3% retention after 300 cycles.

  13. Ultrathin coating of plasma polymer of methane applied on the surface of silicone contact lenses.

    PubMed

    Ho, C P; Yasuda, H

    1988-10-01

    Silicone rubber has great advantages as a contact lens material because of its very high oxygen permeability, softness, and excellent mechanical strength and durability. Practical application is hampered by inherent characteristics of elastomers, i.e., high tackiness and highly hydrophobic surface properties. By applying a thin layer, e.g., 5 nm, of plasma polymer of methane, it was found that all these disadvantages can be eliminated without sacrificing high oxygen permeation rate, e.g., less than 15% reduction. Optimization of operational parameters to achieve this task has been investigated. It was also found that under optimum conditions the coating withstood severe and repeated flexing of the contact lens. PMID:3220842

  14. Ultrathin coating of plasma polymer of methane applied on the surface of silicone contact lenses.

    PubMed

    Ho, C P; Yasuda, H

    1988-10-01

    Silicone rubber has great advantages as a contact lens material because of its very high oxygen permeability, softness, and excellent mechanical strength and durability. Practical application is hampered by inherent characteristics of elastomers, i.e., high tackiness and highly hydrophobic surface properties. By applying a thin layer, e.g., 5 nm, of plasma polymer of methane, it was found that all these disadvantages can be eliminated without sacrificing high oxygen permeation rate, e.g., less than 15% reduction. Optimization of operational parameters to achieve this task has been investigated. It was also found that under optimum conditions the coating withstood severe and repeated flexing of the contact lens.

  15. Physical vs. photolithographic patterning of plasma polymers: an investigation by ToF-SSIMS and multivariate analysis

    PubMed Central

    Mishra, Gautam; Easton, Christopher D.; McArthur, Sally L.

    2009-01-01

    Physical and photolithographic techniques are commonly used to create chemical patterns for a range of technologies including cell culture studies, bioarrays and other biomedical applications. In this paper, we describe the fabrication of chemical micropatterns from commonly used plasma polymers. Atomic force microcopy (AFM) imaging, Time-of-Flight Static Secondary Ion Mass Spectrometry (ToF-SSIMS) imaging and multivariate analysis have been employed to visualize the chemical boundaries created by these patterning techniques and assess the spatial and chemical resolution of the patterns. ToF-SSIMS analysis demonstrated that well defined chemical and spatial boundaries were obtained from photolithographic patterning, while the resolution of physical patterning via a transmission electron microscopy (TEM) grid varied depending on the properties of the plasma system including the substrate material. In general, physical masking allowed diffusion of the plasma species below the mask and bleeding of the surface chemistries. Multivariate analysis techniques including Principal Component Analysis (PCA) and Region of Interest (ROI) assessment were used to investigate the ToF-SSIMS images of a range of different plasma polymer patterns. In the most challenging case, where two strongly reacting polymers, allylamine and acrylic acid were deposited, PCA confirmed the fabrication of micropatterns with defined spatial resolution. ROI analysis allowed for the identification of an interface between the two plasma polymers for patterns fabricated using the photolithographic technique which has been previously overlooked. This study clearly demonstrated the versatility of photolithographic patterning for the production of multichemistry plasma polymer arrays and highlighted the need for complimentary characterization and analytical techniques during the fabrication plasma polymer micropatterns. PMID:19950941

  16. Self-Organization in Hypersonic Shock Driven Plasmas

    NASA Astrophysics Data System (ADS)

    Williams, Kyron; Alexander, A. B.; Scott, M.; Buchanan, J.; Johnson, J. A., III

    2011-10-01

    Evidence has been found using the arc-driven shock tube of self-induced Stark effect lines due to the production of hypersonic shock waves. We take advantage of high time resolution measurements of optical spectral lines. In addition, previous work also indicated a possible means to determine the time evolution of the internal EM field geometry on short time scales (less than 250 microseconds). Further examination of hypersonic argon and krypton plasmas using a phase transition model indicates preliminary evidence of local plasma self-organization and collective behavior. The determination of the system complexity from turbulence analysis also sheds insight into the interaction of hypersonic turbulent plasmas with external magnetic fields. Research supported in part by DOE FES and NSF.

  17. Non-equilibrium plasma reactors for organic solvent destruction

    SciTech Connect

    Yang, C.L.; Beltran, M.R.; Kravets, Z.

    1997-12-31

    Two non-equilibrium plasma reactors were evaluated for their ability to destroy three widely used organic solvents, i.e., 2-butanone, toluene and ethyl acetate. The catalyzed plasma reactor (CPR) with 6 mm glass beads destroys 98% of 50 ppm toluene in air at 24 kV/cm and space velocities of 1,400 v/v/hr. Eighty-five percent of ethyl acetate and 2-butanone are destroyed under the same conditions. The tubular plasma reactor (TPR) has an efficiency of 10% to 20% lower than that of a CPR under the same conditions. The 1,400 v/v/hr in a CPR is equal to a residence time of 2.6 seconds in a TPR. The operating temperatures, corona characteristics, as well as the kinetics of VOC destruction in both TPR and CPR were studied.

  18. Plasma Surface Modification of Polymer Backsheets: Origins of Future Interfacial Barrier/Backsheet Failure

    SciTech Connect

    Pankow, J. W.; Glick, S. H.

    2005-11-01

    Flexible polymer substrates coated with inorganic oxide moisture barriers are a potential replacement for glass backsheets in thin film PV modules. Silicon oxynitride (SiOxNy) deposited by PECVD on polyethylene terephthalate (PET) represents one potential new backsheet candidate. Barrier deposition runs at NREL have typically included a nitrogen-rich plasma pretreatment prior to actual barrier deposition with the intention of cleaning the PET surface as well as enhancing adhesion of the SiOxNy barrier film to PET; however, test coupons of PET/barrier/EVA/TPE failed after damp heat exposure. PET substrates exposed to plasma conditions similar to those used in pre-treatment were examined by X-ray photoelectron spectroscopy (XPS) to reveal new low molecular weight PET fragments are created which are volatile upon heating and water soluble. Failure analysis of the coupons determined that the moisture barrier is, in fact, transferred to the encapsulant side.

  19. Charge carrier mobility in conjugated organic polymers: simulation of an electron mobility in a carbazole-benzothiadiazole-based polymer

    NASA Astrophysics Data System (ADS)

    Li, Yaping; Lagowski, Jolanta B.

    2011-08-01

    Inorganic (mostly silicon based) solar cells are important devices that are used to solve the world energy and environmental needs. Now days, organic solar cells are attracting considerable attention in the field of photovoltaic cells because of their low cost and processing flexibility. Often conjugated polymers are used in the construction of the organic solar cells. We study the conjugated polymers' charge transport using computational approach that involves the use of the density functional theory (DFT), semiempirical (ZINDO), and Monte Carlo (MC) theoretical methods in order to determine their transfer integrals, reorganization energies, transfer rates (with the use of Marcus-Hush equation) and mobilities. We employ the experimentally determined three dimensional (3D) structure of poly(9,9'-di-n-octylfluorene-alt-benzothiadiazole) (F8BT) to estimate the electron mobility in a similar co-alternating polymer consisting of carbazole and benzothiadiazole units (C8BT). In agreement with our previous work, we found that including an orientational disorder in the crystal reduces the electron mobility in C8BT. We hope that the proposed computational approach can be used to predict charge mobility in organic materials that are used in solar cells.

  20. Optimization of molecular organization and nanoscale morphology for high performance low bandgap polymer solar cells

    NASA Astrophysics Data System (ADS)

    He, Ming; Wang, Mengye; Lin, Changjian; Lin, Zhiqun

    2014-03-01

    Rational design and synthesis of low bandgap (LBG) polymers with judiciously tailored HOMO and LUMO levels have emerged as a viable route to high performance polymer solar cells with power conversion efficiencies (PCEs) exceeding 10%. In addition to engineering the energy-level of LBG polymers, the photovoltaic performance of LBG polymer-based solar cells also relies on the device architecture, in particular the fine morphology of the photoactive layer. The nanoscale interpenetrating networks composed of nanostructured donor and acceptor phases are the key to providing a large donor-acceptor interfacial area for maximizing the exciton dissociation and offering a continuous pathway for charge transport. In this Review Article, we summarize recent strategies for tuning the molecular organization and nanoscale morphology toward an enhanced photovoltaic performance of LBG polymer-based solar cells.

  1. Printed organic conductive polymers thermocouples in textile and smart clothing applications.

    PubMed

    Seeberg, Trine M; Røyset, Arne; Jahren, Susannah; Strisland, Frode

    2011-01-01

    This work reports on an experimental investigation of the potential of using selected commercially available organic conductive polymers as active ingredients in thermocouples printed on textiles. Poly(3, 4-ethylenedioxythiophene): poly(4 styrenesulfonate) (PEDOT:PSS) and polyaniline (PANI) were screen printed onto woven cotton textile. The influence of multiple thermocycles between 235 K (-38 °C) and 350 K (+77 °C) on resistivity and thermoelectric properties was examined. The Seebeck coefficients of PEDOT:PSS and PANI were found to be about +18 μV/K and +15 uV/K, respectively, when "metal-polymer" thermocouples were realized by combining the polymer with copper. When "polymer-polymer" thermocouples were formed by combining PEDOT:PSS and PANI, a thermoelectric voltage of about +10 μV/K was observed. A challenge recognized in the experiments is that the generated voltage exhibited drift and fluctuations. PMID:22255039

  2. Atmospheric pressure plasma polymers for tuned QCM detection of protein adhesion.

    PubMed

    Rusu, G B; Asandulesa, M; Topala, I; Pohoata, V; Dumitrascu, N; Barboiu, M

    2014-03-15

    Our efforts have been concentrated in preparing plasma polymeric thin layers at atmospheric pressure grown on Quartz Crystal Microbalance-QCM electrodes for which the non-specific absorption of proteins can be efficiently modulated, tuned and used for QCM biosensing and quantification. Plasma polymerization reaction at atmospheric pressure has been used as a simple and viable method for the preparation of QCM bioactive surfaces, featuring variable protein binding properties. Polyethyleneglycol (ppEG), polystyrene (ppST) and poly(ethyleneglycol-styrene) (ppST-EG) thin-layers have been grown on QCM electrodes. These layers were characterized by Atomic Force Microscopy (AFM), Contact angle measurements, Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). The plasma ppST QCM electrodes present a higher adsorption of Concanavalin A (ConA) and Bovine Serum Albumin (BSA) proteins when compared with the commercial coated polystyrene (ppST) ones. The minimum adsorption was found for ppEG, surface, known by their protein anti-fouling properties. The amount of adsorbed proteins can be tuned by the introduction of PEG precursors in the plasma discharge during the preparation of ppST polymers.

  3. Novel spin-on organic hardmask with high plasma etch resistance

    NASA Astrophysics Data System (ADS)

    Oh, Chang-Il; Lee, Jin-Kuk; Kim, Min-Soo; Yoon, Kyong-Ho; Cheon, Hwan-Sung; Tokareva, Nataliya; Song, Jee-Yun; Kim, Jong-Seob; Chang, Tu-Won

    2008-03-01

    In recent years for memory devices under 70nm using ArF lithography, spin-on organic hardmask has become an attractive alternative process to amorphous carbon layer hardmark (ACL) in mass production due to ACL hardmask's limited capacity, high cost-of-ownership, and low process efficiency in spite of its excellent etch performance. However, insufficient plasma etch resistance of spin-on hardmask makes the etch process an issue resulting in inadequate vertical profiles, large CD bias, and narrow etch process window compared to ACL hardmask. In order to be able to apply these spin on hardmasks to varies layers including critical layers, the aforementioned problems need to be resolved and verified using several evaluation methods including etch pattern evaluation. In this paper, we report the synthesis of novel organic spin-on hardmasks (C-SOH) that incorporate various fused aromatic moieties into polymer chain and the evaluation of etch performance using dry etch tools. Organic spin-on hardmasks with 79-90 wt% carbon contents were synthesized in-house. Oxygen and fluorine based plasma etch processes were used to evaluate the etch resistance of the C-SOH. The results show our 3rd generation C-SOH has etch profiles comparable to that of ACL in a 1:1 dense pattern.

  4. Surfactant-free, low band gap conjugated polymer nanoparticles and polymer:fullerene nanohybrids with potential for organic photovoltaics.

    PubMed

    Wang, Suxiao; Singh, Amita; Walsh, Nichola; Redmond, Gareth

    2016-06-17

    Stable, aqueous dispersions of nanoparticles based on the low band gap polymers poly [2,7-(9,9-dioctyl-fluorene)-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] (APFO-3) and poly [N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] (PCDTBT) were prepared, using a flexible, surfactant-free reprecipitation method, and characterized by a variety of optical techniques. Light scattering measurements indicated average nanoparticle hydrodynamic diameters of approximately 40 nm. The particles presented wide-bandwidth absorption and photoluminescence excitation spectra with high absorption cross-sections on the order of 10(-12) cm(2). Nanoparticle emission spectra were significantly red-shifted, with decreased emission quantum yields and lifetimes, consistent with increased inter-polymer chain interactions in the condensed phase. Single particle photoluminescence studies highlighted the multi-chromophoric nature of the polymer nanoparticles and confirmed their favorable photostabilities. When the nanoparticles were doped with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), the correspondence of photoluminescence emission quenching, quantum yield decreases, emission lifetime shortening, and increased non-radiative rates with increasing PCBM concentration suggested efficient photo-induced donor-to-acceptor charge transfer between the conjugated polymers and the fullerene dopants co-localized in the nanoparticle cores. Taken together, the data suggest that these surfactant-free hybrid nanomaterials may be useful for integration with future nanostructured organic photovoltaics technologies.

  5. Active polymer fibres doped with organic dyes: Generation and amplification of coherent radiation

    SciTech Connect

    Maier, G V; Kopylova, T N; Svetlichnyi, Valerii A; Podgaetskii, Vitalii M; Dolotov, S M; Ponomareva, O V; Monich, A E; Monich, E A

    2007-01-31

    The technology is developed for manufacturing active polymer optical fibres doped with organic dyes. Stimulated emission and amplification in the long-wavelength part of the visible spectrum is studied for rhodamine 11B, phenalemine 512 and substituted DCM pyran in polymer optical fibres. Lasing was observed upon longitudinal and transverse pumping by the second harmonic of a Nd:YAG laser. The gain in polymer fibres was estimated by measuring the intensity ratio of radiation of a master oscillator (dye laser) propagated through the excited (pumped) and unexcited (not pumped) fibre pieces doped with organic dyes. It is shown that the lasing efficiency of rhodamine 11B in a transversely pumped polymer fibre can achieve 36%. The maximum gain (25 dB m{sup -1}) is obtained in fibres doped with phenalemine 512. (lasers)

  6. X-ray and neutron reflectometry study of glow-discharge plasma polymer films.

    PubMed

    Nelson, Andrew; Muir, Benjamin W; Oldham, James; Fong, Celesta; McLean, Keith M; Hartley, Patrick G; Oiseth, Sofia K; James, Michael

    2006-01-01

    Radio-frequency glow-discharge plasma polymer thin films of allylamine (AA) and hexamethyldisiloxane (HMDSO) were prepared on silicon wafers and analyzed by a combination of X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), X-ray reflectometry (XRR), and neutron reflectometry (NR). AFM and XRR measurements revealed uniform, smooth, defect-free films of 20-30 nm thickness. XPS measurements gave compositional data on all elements in the films with the exception of hydrogen. In combination with XRR and NR, the film composition and mass densities (1.46 and 1.09 g cm(-)(3) for AA and HMDSO, respectively) were estimated. Further NR measurements were conducted with the AA and HMDSO films in contact with water at neutral pH. Three different H(2)O/D(2)O mixtures were used to vary the contrast between the aqueous phase and the polymer. The amount of water penetrating the film, as well as the number of labile protons present, was determined. The AA film in contact with water was found to swell by approximately 5%, contain approximately 3% water, and have approximately 24% labile protons. The HDMSO polymer was found to have approximately 6% labile protons, no thickness increase when in contact with water, and essentially no solvent penetration into the film. The difference in the degree of proton exchange within the films was attributed to the substantially different surface and bulk chemistries of the two films. PMID:16378459

  7. 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

  8. From ribbons to networks: hierarchical organization of DNA-grafted supramolecular polymers.

    PubMed

    Vyborna, Yuliia; Vybornyi, Mykhailo; Häner, Robert

    2015-11-11

    DNA-grafted supramolecular polymers (SPs) allow the programmed organization of DNA in a highly regular, one-dimensional array. Oligonucleotides are arranged along the edges of pyrene-based helical polymers. Addition of complementary oligonucleotides triggers the assembly of individual nanoribbons resulting in the development of extended supramolecular networks. Network formation is enabled by cooperative coaxial stacking interactions of terminal GC base pairs. The process is accompanied by structural changes in the pyrene polymer core that can be followed spectroscopically. Network formation is reversible, and disassembly into individual ribbons is realized either via thermal denaturation or by addition of a DNA separator strand.

  9. From ribbons to networks: hierarchical organization of DNA-grafted supramolecular polymers.

    PubMed

    Vyborna, Yuliia; Vybornyi, Mykhailo; Häner, Robert

    2015-11-11

    DNA-grafted supramolecular polymers (SPs) allow the programmed organization of DNA in a highly regular, one-dimensional array. Oligonucleotides are arranged along the edges of pyrene-based helical polymers. Addition of complementary oligonucleotides triggers the assembly of individual nanoribbons resulting in the development of extended supramolecular networks. Network formation is enabled by cooperative coaxial stacking interactions of terminal GC base pairs. The process is accompanied by structural changes in the pyrene polymer core that can be followed spectroscopically. Network formation is reversible, and disassembly into individual ribbons is realized either via thermal denaturation or by addition of a DNA separator strand. PMID:26491956

  10. Magneto-Photoinduced Absorption in Organic Polymer Films

    NASA Astrophysics Data System (ADS)

    Gautam, Bhoj; Nguyen, Tho; Ehrenfreund, Eitan; Vardeny, Z. Valy

    2012-02-01

    In order to elucidate the underlying mechanism of magneto-conductivity (MC) in OLEDs we studied magneto-photoinduced absorption (MPA) response in polymer films. The films were based on the MEH-PPV polymer in three different forms, namely: pristine film; film exposed to prolonged UV illumination; and MEH-PPV/PCBM blend having weight ratio 1:1. In pristine film we show that the MPA at low excitation intensity is due to sublevel spin mixing of triplet excitons; whereas at high excitation intensity the MPA is dominated by the triplet-triplet annihilation process. In UV illuminated MEH-PPV films that support photogenerated polarons we show that the MPA is due to sublevel spin-mixing of polaron-pairs via the hyperfine interaction with the closest hydrogen atoms to the chain. This mechanism also explains the MC response of OLED based on MEH-PPV, since its response is similar to that of MPA. Finally we found that the MPA in MEH-PPV/PCBM blend films is dominated by spin mixing of polaron-pair on the polymer and fullerene molecules, via the δg mechanism. Supported by the NSF DMR-1104495, the NSF MRSEC at the UoU, and the BSF program.

  11. Synthesis and Applications of Inorganic/Organic-Polymer Nanocomposites

    NASA Astrophysics Data System (ADS)

    Goyal, Anubha

    This research work focuses on developing new synthesis routes to fabricate polymer nanocomposites tailored towards different applications. A simple, one-step method has been devised for synthesizing free-standing, flexible metal nanoparticle-polydimethylsiloxane films. This process simplifies prevalent methods to synthesize nanocomposites, in that here nanoparticles are created in situ while curing the polymer. This route circumvents the need for pre-synthesized nanoparticles, external reducing agents and stabilizers, thereby significantly reducing processing time and cost. The resulting nanocomposite also demonstrates enhancement in mechanical and antibacterial properties, with other envisaged applications in biomedical devices and catalysis. Applying the same mechanism as that used for the formation of bulk metalsiloxane nanocomposites, metal core-siloxane shell nanoparticles and siloxane nanowires were synthesized, with octadecylsilane as the precursor and in situ formed metal nanoparticles (gold, silver) as the catalyst. This method offers some unique advantages over the previously existing methods. This is a room temperature route which does not require high temperature refluxing or the use of pre-synthesized nanoparticles. Furthermore, this synthesis process gives a control over the shape of resulting nanocomposite structures (1-D wires or 0-D spherical particles). High thermal stability of polydimethylsiloxane (PDMS) makes it viable to alternatively synthesize metal nanoparticles in the polymer matrix by thermal decomposition process. This technique is generic across a range of metals (palladium, iron, nickel) and results in nanoparticles with a very narrow size distribution. Membranes with palladium nanoparticles demonstrate catalytic activity in ethylene hydrogenation reaction. Additionally, a new nanocomposite electrode has been developed for flexible and light-weight Li-ion batteries. Flexible films were prepared by the integration of the poly

  12. Depolymerization of the waste polymers in municipal solid waste streams using induction-coupled plasma technology

    NASA Astrophysics Data System (ADS)

    Guddeti, Ravikishan Reddy

    2000-10-01

    A significant, valuable percentage of today's municipal solid waste stream consists of polymeric materials, for which almost no economic recycling technology currently exists. This polymeric waste is incinerated, landfilled or recycled via downgraded usage. Thermal plasma treatment is a potentially viable means of recycling these materials by converting them back into monomers or into other useful compounds. The technical, laboratory scale, feasibility of using an induction-coupled RF plasma [ICP] heated reactor for this purpose has been demonstrated in the present study. Polyethylene [PE], polypropylene [PP] and polyethylene terephthalate [PET], the model polymers chosen for the study, were injected axially through the center of an ICP torch. 68% of PE, 78% of PP and 75% of PET were converted into gaseous products. Ethylene and propylene were the primary gaseous products of decomposition of the former two polymers and acetylene was the primary product of the depolymerization of PET. The amount of propylene obtained in PE depolymerization was significantly higher than anticipated and was believed to be due to beta-scission reactions occurring at the high plasma temperatures. Statistical design of experiments was used to determine the influence of individual variables. Analysis of results showed that plasma plate power, central gas flow rate, probe gas flow rate, powder feed rate and the interaction between the quench gas flow rate and power input were the key process parameters affecting the yield of monomer in the product gas stream. Depolymerization of a PE + PP mixture yielded concentrations of propylene and ethylene close to those predicted from weighting the concentrations of products from the individual polymers. 75.5 wt.% of the mixture was converted into monomers. TEM analysis of the carbon residues collected from different locations of the reactor indicated the formation of some novel carbon structures, including carbon nanotubes. The presence of these

  13. Synthesis and gas adsorption properties of tetra-armed microporous organic polymer networks based on triphenylamine.

    PubMed

    Yang, Xiao; Yao, Shuwen; Yu, Miao; Jiang, Jia-Xing

    2014-04-01

    Two novel tetra-armed microporous organic polymers have been designed and synthesized via a nickel-catalyzed Yamamoto-type Ullmann cross-coupling reaction or Suzuki cross-coupling polycondensation. These polymers are stable in various solvents, including concentrated hydrochloric acid, and are thermally stable. The homocoupled polymer YPTPA shows much higher Brunauer-Emmet-Teller-specific surface area up to 1557 m(2) g(-1) than the copolymer SPTPA (544 m(2) g(-1)), and a high CO2 uptake ability of 3.03 mmol g(-1) (1.13 bar/273 K) with a CO2 /N2 sorption selectivity of 17.3:1. Both polymers show high isosteric heats of CO2 adsorption (22.7-26.5 kJ mol(-1)) because the incorporation of nitrogen atoms into the skeleton of microporous organic polymers enhances the interaction between the pore wall and the CO2 molecules. The values are higher than those of the porous aromatic frameworks, which contain neither additional polar functional groups nor nitrogen atoms, and are rather close to those of previously reported microporous organic polymers containing the nitrogen atoms on the pore wall. These data show that these materials would be potential candidates for applications in post-combustion CO2 capture and sequestration technology.

  14. Ionic Liquid-Based Polymer Electrolytes via Surfactant-Assisted Polymerization at the Plasma-Liquid Interface.

    PubMed

    Tran, Quoc Chinh; Bui, Van-Tien; Dao, Van-Duong; Lee, Joong-Kee; Choi, Ho-Suk

    2016-06-29

    We first report an innovative method, which we refer to as interfacial liquid plasma polymerization, to chemically cross-link ionic liquids (ILs). By this method, a series of all-solid state, free-standing polymer electrolytes is successfully fabricated where ILs are used as building blocks and ethylene oxide-based surfactants are employed as an assisted-cross-linking agent. The thickness of the films is controlled by the plasma exposure time or the ratio of surfactant to ILs. The chemical structure and properties of the polymer electrolyte are characterized by scanning electron microscopy (SEM), Fourier transformation infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) spectroscopy, X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), and electrochemical impedance spectroscopy (EIS). Importantly, the underlying polymerization mechanism of the cross-linked IL-based polymer electrolyte is studied to show that fluoroborate or halide anions of ILs together with the aid of a small amount of surfactants having ethylene oxide groups are necessary to form cross-linked network structures of the polymer electrolyte. The ionic conductivity of the obtained polymer electrolyte is 2.28 × 10(-3) S·cm(-1), which is a relatively high value for solid polymer electrolytes synthesized at room temperature. This study can serve as a cornerstone for developing all-solid state polymer electrolytes with promising properties for next-generation electrochemical devices.

  15. 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)

  16. Plasma treatment and its prospective application to polymer light-emitting diodes fabricated by ink-jet printing method

    SciTech Connect

    Jo, Sung Jin; Jeong, Soon Moon; Kim, Woo Jin; Koo, Won Hoi; Choi, Sang Hun; Kim, Chang Su; Baik, Hong Koo; Lee, Se-Jong

    2005-09-15

    The influence of CF{sub 4} plasma treatment of indium-tin-oxide (ITO) and polyimide (PI) on the patterning of ink-jet printed polymer is presented. Not much difference between the as-received ITO and PI surface energies was found, but a significant difference in surface energies between ITO and PI after CF{sub 4} plasma treatment was noted. It is expected that precise patterning can be achieved by using the difference in surface energies between the inside of the pixel and its surroundings. Also the effects of CF{sub 4} plasma treatment of ITO have been studied on the performance of polymer light-emitting diodes (PLEDs). X-ray photoelectron spectroscopy revealed that CF{sub 4} plasma treatment led to a decrease in the surface content of carbon contaminants and an increase in the surface content of fluorine, which in turn enhance the performance of PLEDs.

  17. Syngas Generation from Organic Waste with Plasma Steam Reforming

    NASA Astrophysics Data System (ADS)

    Diaz, G.; Leal-Quiros, E.; Smith, R. A.; Elliott, J.; Unruh, D.

    2014-05-01

    A plasma steam reforming system to process waste is in the process of being set up at the University of California, Merced. The proposed concept will use two different plasma regimes, i.e. glow discharge and arc torches to process a percentage of the total liquid waste stream generated at the campus together with shredded local organic solid waste. One of the main advantages of the plasma technology to be utilized is that it uses graphite electrodes that can be fed to the reactor to achieve continuous operation, thus, electrode or nozzle life is not a concern. The waste to energy conversion process consists of two stages, one where a mixture of steam and hydrogen is generated from the liquid in a glow-discharge cell, and a second stage where the mixture of exhaust gases coming out of the first device are mixed with solid waste in a reactor operating in steam reforming mode interacting with a plasma torch to generate high-quality syngas. In this paper, the results of a thermodynamic model developed for the two stages are shown. The syngas composition obtained indicates that the fraction of CO2 present decreases with increasing temperature and the molar fractions of hydrogen and carbon monoxide become dominant. The fraction of water vapour present in the product gases coming out of the second stage needs to be condensed before the syngas can be utilized in a prime mover.

  18. Ferroelectric Polymer Matrix for Probing Molecular Organization in Perylene Diimides.

    PubMed

    Chellappan, Kishore V; Kandappa, Sunil Kumar; Rajaram, Sridhar; Narayan, K S

    2015-01-15

    Ferroelectric films of poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) provide a controlled environment to study the aggregation tendency of functional molecules such as perylene diimides (PDIs). The local electric field and free volume confinement parameters offered by the matrix are tailored to study the organizational and assembly characteritics of molecular acceptors. The optical properties of planar and nonplanar PDIs in the ferroelectric polymer matrix were studied systematically over a wide range that encompassed the ferroelectric transition temperature. This approach provides valuable insight into the properties of molecular materials used in applications ranging from bulk heterostructure-based photovoltaics to nonlinear optical materials.

  19. Conjugated polymer particles: towards self-assembling organic photonics

    NASA Astrophysics Data System (ADS)

    Kuehne, Alexander J. C.; Luelf, Tobias; Wessling, Matthias; Sprakel, Joris

    2013-09-01

    The preparation of conjugated polymer particles with uniform size is presented and discussed. The particles can selfassemble into photonic crystal arrangements exhibiting a photonic band-gap. This way, active optical assemblies with an optical stop-band and an independent fluorescence band can be fabricated. To showcase the applicability of the particles, which can be processed from dispersion, optical core sheath fibers are presented. The particles can be extruded into the core of the fiber with polyacrylonitrile as the cladding material. The particle dispersions can be easily processed by dryspinning and are confined to only the core of the fiber, where they assemble into a random close packing.

  20. Unraveling the effect of polymer dots doping in inverted low bandgap organic solar cells.

    PubMed

    Zhang, Xinyuan; Liu, Chunyu; Li, Jinfeng; He, Yeyuan; Li, Zhiqi; Li, Hao; Shen, Liang; Guo, Wenbin; Ruan, Shengping

    2015-06-28

    In this study, molecular doping with polymer dots was designed to unravel its effect on the photoconductivity in organic solar cells. The photocurrent in organic solar cells exhibited a considerable increase under optimal doping concentration, leading to an ultimate enhancement of power conversion efficiency from 2.30% to 3.64%. This can be attributed primarily to the improvement of the initial boost in charge carriers due to the background carriers induced by the polymer dots and increased tail absorption by the active layer. Based on single carrier device and impedance measurements, polymer dopant can efficiently decrease charge recombination and improve charge carriers mobilities. The obtained achievements pave an approach of molecular doping in affecting the operation of organic solar cells.

  1. An X-ray and neutron reflectometry study of ‘PEG-like’ plasma polymer films

    PubMed Central

    Menzies, Donna J.; Nelson, Andrew; Shen, Hsin-Hui; McLean, Keith M.; Forsythe, John S.; Gengenbach, Thomas; Fong, Celesta; Muir, Benjamin W.

    2012-01-01

    Plasma-enhanced chemical vapour-deposited films of di(ethylene glycol) dimethyl ether were analysed by a combination of X-ray photoelectron spectroscopy, atomic force microscopy, quartz crystal microbalance with dissipation monitoring (QCM-D), X-ray and neutron reflectometry (NR). The combination of these techniques enabled a systematic study of the impact of plasma deposition conditions upon resulting film chemistry (empirical formula), mass densities, structure and water solvation, which has been correlated with the films' efficacy against protein fouling. All films were shown to contain substantially less hydrogen than the original monomer and absorb a vast amount of water, which correlated with their mass density profiles. A proportion of the plasma polymer hydrogen atoms were shown to be exchangeable, while QCM-D measurements were inaccurate in detecting associated water in lower power films that contained loosely bound material. The higher protein resistance of the films deposited at a low load power was attributed to its greater chemical and structural similarity to that of poly(ethylene glycol) graft surfaces. These studies demonstrate the utility of using X-ray and NR analysis techniques in furthering the understanding of the chemistry of these films and their interaction with water and proteins. PMID:21957120

  2. Plasma Surface Modification of Polymer Backsheets: Origins of Future Interfacial Barrier/Backsheet Failure (Poster)

    SciTech Connect

    Pankow, J. W.; Glick, S. H.

    2006-05-01

    Flexible polymer substrates coated with inorganic oxide moisture barriers are a potential replacement for glass backsheets in thin-film PV (photovoltaic) modules. Silicon oxynitride (SiO{sub x}N{sub y}) deposited by plasma enhanced chemical vapor deposition (PECVD) on polyethylene terephthalate (PET) represents one potential new backsheet candidate. Barrier deposition runs at NREL have included a nitrogen-rich plasma pretreatment prior to barrier deposition with the intention of cleaning the PET surface and enhancing adhesion of the SiO{sub x}N{sub y} barrier film to PET; however, test coupons of PET/barrier/EVA/TPE failed after damp-heat exposure. (EVA is ethylene vinyl acetate and TPE is Tedlar{reg_sign}-PET-EVA). PET substrates exposed to plasma conditions similar to those used in pretreatment were examined by X-ray photoelectron spectroscopy (XPS) to reveal that new low molecular weight PET fragments were created at the PET surface. These fragments are responsible for barrier/PET interfacial failure and barrier transfer to the EVA encapsulant side following damp heat exposure.

  3. Multilayer Coextrusion of Polymer Composites to Develop Organic Capacitors

    DOE PAGES

    Mondy, L.; Mrozek, R.; Rao, R.; Lenhart, J.; Bieg, L.; Spangler, S.; Stavig, M.; Schroeder, J.; Winter, M.; Diantonio, C.; et al

    2015-05-29

    Multilayer coextrusion is applied to produce a tape containing layers of alternating electrical properties to demonstrate the potential for using coextrusion to manufacture capacitors. To obtain the desired properties, we develop two filled polymer systems, one for conductive layers and one for dielectric layers. We describe numerical models used to help determine the material and processing parameters that impact processing and layer stability. These models help quantify the critical ratios of densities and viscosities of the two layers to maintain stable layers, as well as the effect of increasing the flow rate of one of the two materials. The conductingmore » polymer is based on polystyrene filled with a blend of low-melting-point eutectic metal and nickel particulate filler, as described by Mrozek et al. (2010). The appropriate concentrations of fillers are determined by balancing measured conductivity with processability in a twin screw extruder. Based on results of the numerical models and estimates of the viscosity of emulsions and suspensions, a dielectric layer composed of polystyrene filled with barium titanate is formulated. Despite the fact that the density of the dielectric filler is less than the metallic filler of the conductive phase, as well as rheological measurements that later showed that the dielectric formulation is not an ideal match to the viscosity of the conductive material, the two materials can be successfully coextruded if the flow rates of the two materials are not identical. A measurable capacitance of the layered structure is obtained.« less

  4. Multilayer Coextrusion of Polymer Composites to Develop Organic Capacitors

    SciTech Connect

    Mondy, L.; Mrozek, R.; Rao, R.; Lenhart, J.; Bieg, L.; Spangler, S.; Stavig, M.; Schroeder, J.; Winter, M.; Diantonio, C.; Collins, R.

    2015-05-29

    Multilayer coextrusion is applied to produce a tape containing layers of alternating electrical properties to demonstrate the potential for using coextrusion to manufacture capacitors. To obtain the desired properties, we develop two filled polymer systems, one for conductive layers and one for dielectric layers. We describe numerical models used to help determine the material and processing parameters that impact processing and layer stability. These models help quantify the critical ratios of densities and viscosities of the two layers to maintain stable layers, as well as the effect of increasing the flow rate of one of the two materials. The conducting polymer is based on polystyrene filled with a blend of low-melting-point eutectic metal and nickel particulate filler, as described by Mrozek et al. (2010). The appropriate concentrations of fillers are determined by balancing measured conductivity with processability in a twin screw extruder. Based on results of the numerical models and estimates of the viscosity of emulsions and suspensions, a dielectric layer composed of polystyrene filled with barium titanate is formulated. Despite the fact that the density of the dielectric filler is less than the metallic filler of the conductive phase, as well as rheological measurements that later showed that the dielectric formulation is not an ideal match to the viscosity of the conductive material, the two materials can be successfully coextruded if the flow rates of the two materials are not identical. A measurable capacitance of the layered structure is obtained.

  5. Systematic Analysis of Polymer Molecular Weight Influence on the Organic Photovoltaic Performance.

    PubMed

    Katsouras, Athanasios; Gasparini, Nicola; Koulogiannis, Chrysanthos; Spanos, Michael; Ameri, Tayebeh; Brabec, Christoph J; Chochos, Christos L; Avgeropoulos, Apostolos

    2015-10-01

    The molecular weight of an electron donor-conjugated polymer is as essential as other well-known parameters in the chemical structure of the polymer, such as length and the nature of any side groups (alkyl chains) positioned on the polymeric backbone, as well as their placement, relative strength, the ratio of the donor and acceptor moieties in the backbone of donor-acceptor (D-A)-conjugated polymers, and the arrangement of their energy levels for organic photovoltaic performance. Finding the "optimal" molecular weight for a specific conjugated polymer is an important aspect for the development of novel photovoltaic polymers. Therefore, it is evident that the chemistry of functional conjugated polymers faces major challenges and materials have to adopt a broad range of specifications in order to be established for high photovoltaic performance. In this review, the approaches followed for enhancing the molecular weight of electron-donor polymers are presented in detail, as well as how this influences the optoelectronic properties, charge transport properties, structural conformation, morphology, and the photovoltaic performance of the active layer.

  6. 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

  7. Polymer Organic Light-Emitting Devices with Cathodes Transferred under Ambient Conditions

    NASA Astrophysics Data System (ADS)

    Lee, Dong-Hyun; Liu, Yan-Peng; Jung, Eun; Seo, Seung-Woo; Chae, Heeyeop; Cho, Sung M.

    2011-11-01

    We fabricated polymer organic light-emitting devices (OLEDs) with an aluminum cathode transferred under ambient conditions from a separately prepared transfer film in order to achieve complete, vacuum-free fabrication of polymer OLEDs. Transfer of aluminum (Al) and lithium fluoride on aluminum (LiF/Al) onto polymer OLEDs as a cathode revealed problems in device performance due to native aluminum oxide and the stability of the LiF layer under ambient conditions, respectively. In contrast, the device fabricated with the transfer of cesium carbonate (Cs2CO3)-doped poly(vinyl alcohol) (PVA) on aluminum as a cathode showed lower turn-on voltage, and enhanced efficiency and stability. This method may provide an easy way to fabricate low-cost polymer OLEDs using complete, vacuum-free processes.

  8. Shape-tailored polymer colloids on the road to become structural motifs for hierarchically organized materials.

    PubMed

    Plüisch, Claudia Simone; Wittemann, Alexander

    2013-12-01

    Anisometric polymer colloids are likely to behave differently when compared with centrosymmetric particles. Their study may not only shine new light on the organization of matter; they may also serve as building units with specific symmetries and complexity to build new materials from them. Polymer colloids of well-defined complex geometries can be obtained by packing a limited number of spherical polymer particles into clusters with defined configurations. Such supracolloidal architectures can be fabricated at larger scales using narrowly dispersed emulsion droplets as templates. Assemblies built from at least two different types of particles as elementary building units open perspectives in selective targeting of colloids with specific properties, aiming for mesoscale building blocks with tailor-made morphologies and multifunctionality. Polymer colloids with defined geometries are also ideal to study shape-dependent properties such as the diffusion of complex particles.

  9. Polymers as fuel for laser-based microthrusters: An investigation of thrust, material, plasma and shockwave properties

    NASA Astrophysics Data System (ADS)

    Urech, L.; Lippert, T.; Phipps, C. R.; Wokaun, A.

    2007-07-01

    The micro-laser plasma thruster (μ-LPT) is a micropropulsion device, designed for steering and propelling of small satellites (1-10 kg). A laser is focused onto a polymer layer on a substrate to form a plasma, which produces the thrust that is used to control the satellite motion. Three different polymers were tested to understand the influence of their specific properties on the thrust performance: poly(vinyl chloride) (PVC) as a low-energetic material, a glycidyl azide polymer (GAP), and poly(vinyl nitrate) (PVN) as high-energetic polymers. Different absorbers (carbon nanoparticles or an IR dye) were added to the polymer to achieve absorption at the irradiation wavelength (1064 nm). The influence of the material and dopant properties on the decomposition characteristics and the energy release were investigated by thrust measurements and ns-shadowgraphy. Mass spectrometry and time- and space-resolved plasma emission spectroscopy in air and vacuum were used to analyze the degree of fragmentation as function of the material properties. The kinetic energies of selected fragments were calculated from the spectra. GAP + C showed the best performance in all measurements at high fluences, while at low fluences PVN + C revealed the best performance.

  10. Branched terthiophenes in organic electronics: from small molecules to polymers.

    PubMed

    Scheuble, Martin; Goll, Miriam; Ludwigs, Sabine

    2015-01-01

    A zoo of chemical structures is accessible when the branched unit 2,2':3',2″-terthiophene (3T) is included both in structurally well-defined small molecules and polymer-like architectures. The first part of this review article highlights literature on all-thiophene based branched oligomers including dendrimers as well as combinations of 3T-units with functional moieties for light-harvesting systems. Motivated by the perfectly branched macromolecular dendrimers both electropolymerization as well as chemical approaches are presented as methods for the preparation of branched polythiophenes with different branching densities. Structure-function relationships between the molecular architecture and optical and electronic properties are discussed throughout the article.

  11. Control of self organization in conjugated polymer fibers.

    PubMed

    Chuangchote, Surawut; Fujita, Michiyasu; Sagawa, Takashi; Sakaguchi, Hiroshi; Yoshikawa, Susumu

    2010-11-01

    We propose new strategy to facilitate the fabrication of conjugated polymer fiber with higher oriented structures, which focused on electrospinning of a blend solution of regioregular poly(3-hexylthiophene) (rr-P3HT) and poly(vinyl pyrrolidone) (PVP). SEM observation revealed that the blend system forms homogeneous composite nanofibers. This system exhibits the specific feature of strong interchain contribution of P3HT from UV-vis absorption, fluorescence spectroscopic, XRD, and photoelectron spectrometric (for HOMO levels) investigations. We also demonstrate the removal of the PVP component from the P3HT/PVP composite fibers through the selective extraction and such strong interchain stacking of pristine P3HT fiber mat can be remarkably maintained.

  12. Silk Fibroin as an Organic Polymer for Controlled Drug Delivery

    SciTech Connect

    Hofmann,S.; Wong Po Foo, C.; Rossetti, F.; Textor, M.; Vunjak-Novakovic, G.; Kaplan, D.; Merkle, H.; Meinel, L.

    2006-01-01

    The pharmaceutical utility of silk fibroin (SF) materials for drug delivery was investigated. SF films were prepared from aqueous solutions of the fibroin protein polymer and crystallinity was induced and controlled by methanol treatment. Dextrans of different molecular weights, as well as proteins, were physically entrapped into the drug delivery device during processing into films. Drug release kinetics were evaluated as a function of dextran molecular weight, and film crystallinity. Treatment with methanol resulted in an increase in {beta}-sheet structure, an increase in crystallinity and an increase in film surface hydrophobicity determined by FTIR, X-ray and contact angle techniques, respectively. The increase in crystallinity resulted in the sustained release of dextrans of molecular weights ranging from 4 to 40 kDa, whereas for less crystalline films sustained release was confined to the 40 kDa dextran. Protein release from the films was studied with horseradish peroxidase (HRP) and lysozyme (Lys) as model compounds. Enzyme release from the less crystalline films resulted in a biphasic release pattern, characterized by an initial release within the first 36 h, followed by a lag phase and continuous release between days 3 and 11. No initial burst was observed for films with higher crystallinity and subsequent release patterns followed linear kinetics for HRP, or no substantial release for Lys. In conclusion, SF is an interesting polymer for drug delivery of polysaccharides and bioactive proteins due to the controllable level of crystallinity and the ability to process the biomaterial in biocompatible fashion under ambient conditions to avoid damage to labile compounds to be delivered.

  13. Enhancement in biological response of Ag-nano composite polymer membranes using plasma treatment for fabrication of efficient bio materials

    NASA Astrophysics Data System (ADS)

    Agrawal, Narendra Kumar; Sharma, Tamanna Kumari; Chauhan, Manish; Agarwal, Ravi; Vijay, Y. K.; Swami, K. C.

    2016-05-01

    Biomaterials are nonviable material used in medical devices, intended to interact with biological systems, which are becoming necessary for the development of artificial material for biological systems such as artificial skin diaphragm, valves for heart and kidney, lenses for eye etc. Polymers having novel properties like antibacterial, antimicrobial, high adhesion, blood compatibility and wettability are most suitable for synthesis of biomaterial, but all of these properties does not exist in any natural or artificial polymeric material. Nano particles and plasma treatment can offer these properties to the polymers. Hence a new nano-biomaterial has been developed by modifying the surface and chemical properties of Ag nanocomposite polymer membranes (NCPM) by Argon ion plasma treatment. These membranes were characterized using different techniques for surface and chemical modifications occurred. Bacterial adhesion and wettability were also tested for these membranes, to show direct use of this new class of nano-biomaterial for biomedical applications.

  14. Surfactant-free, low band gap conjugated polymer nanoparticles and polymer:fullerene nanohybrids with potential for organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Wang, Suxiao; Singh, Amita; Walsh, Nichola; Redmond, Gareth

    2016-06-01

    Stable, aqueous dispersions of nanoparticles based on the low band gap polymers poly [2,7-(9,9-dioctyl-fluorene)-alt-5,5-(4‧,7‧-di-2-thienyl-2‧,1‧,3‧-benzothiadiazole)] (APFO-3) and poly [N-9‧-heptadecanyl-2,7-carbazole-alt-5,5-(4‧,7‧-di-2-thienyl-2‧,1‧,3‧-benzothiadiazole)] (PCDTBT) were prepared, using a flexible, surfactant-free reprecipitation method, and characterized by a variety of optical techniques. Light scattering measurements indicated average nanoparticle hydrodynamic diameters of approximately 40 nm. The particles presented wide-bandwidth absorption and photoluminescence excitation spectra with high absorption cross-sections on the order of 10-12 cm2. Nanoparticle emission spectra were significantly red-shifted, with decreased emission quantum yields and lifetimes, consistent with increased inter-polymer chain interactions in the condensed phase. Single particle photoluminescence studies highlighted the multi-chromophoric nature of the polymer nanoparticles and confirmed their favorable photostabilities. When the nanoparticles were doped with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), the correspondence of photoluminescence emission quenching, quantum yield decreases, emission lifetime shortening, and increased non-radiative rates with increasing PCBM concentration suggested efficient photo-induced donor-to-acceptor charge transfer between the conjugated polymers and the fullerene dopants co-localized in the nanoparticle cores. Taken together, the data suggest that these surfactant-free hybrid nanomaterials may be useful for integration with future nanostructured organic photovoltaics technologies.

  15. Surfactant-free, low band gap conjugated polymer nanoparticles and polymer:fullerene nanohybrids with potential for organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Wang, Suxiao; Singh, Amita; Walsh, Nichola; Redmond, Gareth

    2016-06-01

    Stable, aqueous dispersions of nanoparticles based on the low band gap polymers poly [2,7-(9,9-dioctyl-fluorene)-alt-5,5-(4‧,7‧-di-2-thienyl-2‧,1‧,3‧-benzothiadiazole)] (APFO-3) and poly [N-9‧-heptadecanyl-2,7-carbazole-alt-5,5-(4‧,7‧-di-2-thienyl-2‧,1‧,3‧-benzothiadiazole)] (PCDTBT) were prepared, using a flexible, surfactant-free reprecipitation method, and characterized by a variety of optical techniques. Light scattering measurements indicated average nanoparticle hydrodynamic diameters of approximately 40 nm. The particles presented wide-bandwidth absorption and photoluminescence excitation spectra with high absorption cross-sections on the order of 10‑12 cm2. Nanoparticle emission spectra were significantly red-shifted, with decreased emission quantum yields and lifetimes, consistent with increased inter-polymer chain interactions in the condensed phase. Single particle photoluminescence studies highlighted the multi-chromophoric nature of the polymer nanoparticles and confirmed their favorable photostabilities. When the nanoparticles were doped with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), the correspondence of photoluminescence emission quenching, quantum yield decreases, emission lifetime shortening, and increased non-radiative rates with increasing PCBM concentration suggested efficient photo-induced donor-to-acceptor charge transfer between the conjugated polymers and the fullerene dopants co-localized in the nanoparticle cores. Taken together, the data suggest that these surfactant-free hybrid nanomaterials may be useful for integration with future nanostructured organic photovoltaics technologies.

  16. Laser Plasma Soft X-Ray Contact Microscopy of Polymer Composites

    NASA Astrophysics Data System (ADS)

    Azuma, Hirozumi; Takeichi, Akihiro; Noda, Shoji

    1994-08-01

    Microstructures of polymer composites are observed with a good contrast and with a submicron spatial resolution by contact soft X-ray microscopy with a laser plasma as a soft X-ray source. An iron target was irradiated by a YAG laser ( 2ω=532 nm, 0.4 J) at laser power density of 2.5×1012 W/cm2 and the emitted soft X-rays were filtered with a thin aluminum foil. For a 0.1-µ m-thick poly acrylonitrile-butadiene-styrene specimen, poly-butadiene or copolymer of butadiene spheres of about 500 nm diameter, which are selectively stained with osmium, is observed with soft X-rays in the wavelength region between 17 and 20 nm. For a 4-µ m-thick polyvinyl chloride film specimen formed by polymer powder compaction, peripheral areas of holes, grain boundaries, and areas probably degraded by HCl reduction are observed with soft X-rays in the wavelength region mainly around 2 nm.

  17. Molecular systems under shock compression into the dense plasma regime: carbon dioxide and hydrocarbon polymers

    NASA Astrophysics Data System (ADS)

    Mattsson, Thomas R.; Cochrane, Kyle R.; Root, Seth; Carpenter, John H.

    2013-10-01

    Density Functional Theory (DFT) has proven remarkably accurate in predicting properties of matter under shock compression into the dense plasma regime. Materials where chemistry plays a role are of interest for many applications, including planetary science and inertial confinement fusion (ICF). As examples of systems where chemical reactions are important, and demonstration of the high fidelity possible for these both structurally and chemically complex systems, we will discuss shock- and re-shock of liquid carbon dioxide (CO2) in the range 100 to 800 GPa and shock compression of hydrocarbon polymers, including GDP (glow discharge polymer) which is used as an ablator in laser ICF experiments. Experimental results from Sandia's Z machine validate the DFT simulations at extreme conditions and the combination of experiment and DFT provide reliable data for evaluating existing and constructing future wide-range equations of state models for molecular compounds. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  18. Entropy-driven spatial organization of highly confined polymers: Lessons for the bacterial chromosome

    NASA Astrophysics Data System (ADS)

    Jun, Suckjoon; Mulder, Bela

    2006-08-01

    Despite recent progress in visualization experiments, the mechanism underlying chromosome segregation in bacteria still remains elusive. Here we address a basic physical issue associated with bacterial chromosome segregation, namely the spatial organization of highly confined, self-avoiding polymers (of nontrivial topology) in a rod-shaped cell-like geometry. Through computer simulations, we present evidence that, under strong confinement conditions, topologically distinct domains of a polymer complex effectively repel each other to maximize their conformational entropy, suggesting that duplicated circular chromosomes could partition spontaneously. This mechanism not only is able to account for the spatial separation per se but also captures the major features of the spatiotemporal organization of the duplicating chromosomes observed in Escherichia coli and Caulobacter crescentus. bacterial chromosome segregation | Caulobacter crescentus | Escherichia coli | polymer physics

  19. Ceramic silicon-boron-carbon fibers from organic silicon-boron-polymers

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

    Novel high strength ceramic fibers derived from boron, silicon, and carbon organic precursor polymers are discussed. The ceramic fibers are thermally stable up to and beyond 1200 C in air. The method of preparation of the boron-silicon-carbon fibers from a low oxygen content organosilicon boron precursor polymer of the general formula Si(R2)BR(sup 1) includes melt-spinning, crosslinking, and pyrolysis. Specifically, the crosslinked (or cured) precursor organic polymer fibers do not melt or deform during pyrolysis to form the silicon-boron-carbon ceramic fiber. These novel silicon-boron-carbon ceramic fibers are useful in high temperature applications because they retain tensile and other properties up to 1200 C, from 1200 to 1300 C, and in some cases higher than 1300 C.

  20. Novel hybrid organic thermoelectric materials:three-component hybrid films consisting of a nanoparticle polymer complex, carbon nanotubes, and vinyl polymer.

    PubMed

    Toshima, Naoki; Oshima, Keisuke; Anno, Hiroaki; Nishinaka, Takahiko; Ichikawa, Shoko; Iwata, Arihiro; Shiraishi, Yukihide

    2015-04-01

    A novel class of hybrid organic thermoelectric materials is demonstrated for the first time for constructing flexible thermoelectric devices on polyimide substrates with high output power by using nanotechnology instead of conducting polymers such as poly(3,4-ethylenedioxythiophene). The hybrid organic thermoelectric materials are composed of nanoparticles of a polymer complex, carbon nanotubes, and poly(vinyl chloride), and show high performance (dimensionless thermoelectric figure-of-merit, ZT ≈ 0.3, based on the thermal conductivity through the film).

  1. Study of organic pollutants oxidation by atmospheric plasma discharge

    NASA Astrophysics Data System (ADS)

    Gumuchian, Diane; Cavadias, Simeon; Duten, Xavier; Tatoulian, Michael; da Costa, Patrick; Ognier, Stephanie

    2013-09-01

    Ozonation is one of the usual steps in water treatment processes. However, some organic molecules (acetic acid) cannot be decomposed during ozonation. In that context, we are developing an Advanced Oxidation Process based on the use of a needle plate discharge at atmospheric pressure. The process is a reactor with a plasma discharge between a high voltage electrode and the solution in controlled atmosphere. Characterizations of the plasma obtained in different atmospheres were carried out (Optical Emission Spectroscopy, iCCD camera observations, etc). The efficiency of the process was evaluated by the percentage of degradation of the model-pollutant, measured by liquid chromatography analysis. Treatments in nitrogen lead to the formation of NOx species that decrease the efficiency of the process. Indeed, NOx lead to the consumption of actives species created. Treatments in argon are the most efficient. Two hypotheses are considered: (i) metastable argon participates to the degradation of acetic acid or to the formation of radicals (ii) discharges in argon lead to the formation of many streamers of low energy that increase the interface plasma/solution.

  2. Self-organized, gratinglike nanostructures in polymer films with embedded metal nanoparticles induced by femtosecond laser irradiation

    NASA Astrophysics Data System (ADS)

    Loeschner, K.; Seifert, G.; Heilmann, A.

    2010-10-01

    The self-organized formation of periodic superstructures in thin plasma polymer films containing noble metal nanoparticles upon femtosecond laser irradiation has been studied in detail. By applying several hundred laser pulses on average per spot, the nanostructure of the metal layer is persistently changed into an approximate line grating with periodical changes in particle size and shape as observed by scanning and transmission electron microscopy. The formation of the structures is only possible within rather narrow ranges of laser intensity and metal content. The orientation of the lines is given by the laser polarization, while their spatial periodicity depends on laser wavelength and incidence angle. These observations give evidence that interference of incident light with light scattered into the film plane is the main mechanism controlling the nanostructure formation. We also discuss the optical spectra of the irradiated regions, in particular the observed dichroism and its relation to the prepared periodic structures.

  3. Rapid removal of organic micropollutants from water by a porous β-cyclodextrin polymer.

    PubMed

    Alsbaiee, Alaaeddin; Smith, Brian J; Xiao, Leilei; Ling, Yuhan; Helbling, Damian E; Dichtel, William R

    2016-01-14

    The global occurrence in water resources of organic micropollutants, such as pesticides and pharmaceuticals, has raised concerns about potential negative effects on aquatic ecosystems and human health. Activated carbons are the most widespread adsorbent materials used to remove organic pollutants from water but they have several deficiencies, including slow pollutant uptake (of the order of hours) and poor removal of many relatively hydrophilic micropollutants. Furthermore, regenerating spent activated carbon is energy intensive (requiring heating to 500-900 degrees Celsius) and does not fully restore performance. Insoluble polymers of β-cyclodextrin, an inexpensive, sustainably produced macrocycle of glucose, are likewise of interest for removing micropollutants from water by means of adsorption. β-cyclodextrin is known to encapsulate pollutants to form well-defined host-guest complexes, but until now cross-linked β-cyclodextrin polymers have had low surface areas and poor removal performance compared to conventional activated carbons. Here we crosslink β-cyclodextrin with rigid aromatic groups, providing a high-surface-area, mesoporous polymer of β-cyclodextrin. It rapidly sequesters a variety of organic micropollutants with adsorption rate constants 15 to 200 times greater than those of activated carbons and non-porous β-cyclodextrin adsorbent materials. In addition, the polymer can be regenerated several times using a mild washing procedure with no loss in performance. Finally, the polymer outperformed a leading activated carbon for the rapid removal of a complex mixture of organic micropollutants at environmentally relevant concentrations. These findings demonstrate the promise of porous cyclodextrin-based polymers for rapid, flow-through water treatment. PMID:26689365

  4. Rapid removal of organic micropollutants from water by a porous β-cyclodextrin polymer.

    PubMed

    Alsbaiee, Alaaeddin; Smith, Brian J; Xiao, Leilei; Ling, Yuhan; Helbling, Damian E; Dichtel, William R

    2016-01-14

    The global occurrence in water resources of organic micropollutants, such as pesticides and pharmaceuticals, has raised concerns about potential negative effects on aquatic ecosystems and human health. Activated carbons are the most widespread adsorbent materials used to remove organic pollutants from water but they have several deficiencies, including slow pollutant uptake (of the order of hours) and poor removal of many relatively hydrophilic micropollutants. Furthermore, regenerating spent activated carbon is energy intensive (requiring heating to 500-900 degrees Celsius) and does not fully restore performance. Insoluble polymers of β-cyclodextrin, an inexpensive, sustainably produced macrocycle of glucose, are likewise of interest for removing micropollutants from water by means of adsorption. β-cyclodextrin is known to encapsulate pollutants to form well-defined host-guest complexes, but until now cross-linked β-cyclodextrin polymers have had low surface areas and poor removal performance compared to conventional activated carbons. Here we crosslink β-cyclodextrin with rigid aromatic groups, providing a high-surface-area, mesoporous polymer of β-cyclodextrin. It rapidly sequesters a variety of organic micropollutants with adsorption rate constants 15 to 200 times greater than those of activated carbons and non-porous β-cyclodextrin adsorbent materials. In addition, the polymer can be regenerated several times using a mild washing procedure with no loss in performance. Finally, the polymer outperformed a leading activated carbon for the rapid removal of a complex mixture of organic micropollutants at environmentally relevant concentrations. These findings demonstrate the promise of porous cyclodextrin-based polymers for rapid, flow-through water treatment.

  5. Rapid removal of organic micropollutants from water by a porous β-cyclodextrin polymer

    NASA Astrophysics Data System (ADS)

    Alsbaiee, Alaaeddin; Smith, Brian J.; Xiao, Leilei; Ling, Yuhan; Helbling, Damian E.; Dichtel, William R.

    2016-01-01

    The global occurrence in water resources of organic micropollutants, such as pesticides and pharmaceuticals, has raised concerns about potential negative effects on aquatic ecosystems and human health. Activated carbons are the most widespread adsorbent materials used to remove organic pollutants from water but they have several deficiencies, including slow pollutant uptake (of the order of hours) and poor removal of many relatively hydrophilic micropollutants. Furthermore, regenerating spent activated carbon is energy intensive (requiring heating to 500-900 degrees Celsius) and does not fully restore performance. Insoluble polymers of β-cyclodextrin, an inexpensive, sustainably produced macrocycle of glucose, are likewise of interest for removing micropollutants from water by means of adsorption. β-cyclodextrin is known to encapsulate pollutants to form well-defined host-guest complexes, but until now cross-linked β-cyclodextrin polymers have had low surface areas and poor removal performance compared to conventional activated carbons. Here we crosslink β-cyclodextrin with rigid aromatic groups, providing a high-surface-area, mesoporous polymer of β-cyclodextrin. It rapidly sequesters a variety of organic micropollutants with adsorption rate constants 15 to 200 times greater than those of activated carbons and non-porous β-cyclodextrin adsorbent materials. In addition, the polymer can be regenerated several times using a mild washing procedure with no loss in performance. Finally, the polymer outperformed a leading activated carbon for the rapid removal of a complex mixture of organic micropollutants at environmentally relevant concentrations. These findings demonstrate the promise of porous cyclodextrin-based polymers for rapid, flow-through water treatment.

  6. Oxygen plasma treatment and deposition of CN{sub x} on a fluorinated polymer matrix composite for improved erosion resistance

    SciTech Connect

    Muratore, C.; Korenyi-Both, A.; Bultman, J. E.; Waite, A. R.; Jones, J. G.; Storage, T. M.; Voevodin, A. A.

    2007-07-15

    The use of polymer matrix composites in aerospace propulsion applications is currently limited by insufficient resistance to erosion by abrasive media. Erosion resistant coatings may provide necessary protection; however, adhesion to many high temperature polymer matrix composite (PMC) materials is poor. A low pressure oxygen plasma treatment process was developed to improve adhesion of CN{sub x} coatings to a carbon reinforced, fluorinated polymer matrix composite. Fullerene-like CN{sub x} was selected as an erosion resistant coating for its high hardness-to-elastic modulus ratio and elastic resilience which were expected to reduce erosion from media incident at different angles (normal or glancing) relative to the surface. In situ x-ray photoelectron spectroscopy was used to evaluate the effect of the plasma treatment on surface chemistry, and electron microscopy was used to identify changes in the surface morphology of the PMC substrate after plasma exposure. The fluorine concentration at the surface was significantly reduced and the carbon fibers were exposed after plasma treatment. CN{sub x} coatings were then deposited on oxygen treated PMC substrates. Qualitative tests demonstrated that plasma treatment improved coating adhesion resulting in an erosion resistance improvement of a factor of 2 compared to untreated coated composite substrates. The combination of PMC pretreatment and coating with CN{sub x} reduced the erosion rate by an order of magnitude for normally incident particles.

  7. Organization and Dynamics of Receptor Proteins in a Plasma Membrane.

    PubMed

    Koldsø, Heidi; Sansom, Mark S P

    2015-11-25

    The interactions of membrane proteins are influenced by their lipid environment, with key lipid species able to regulate membrane protein function. Advances in high-resolution microscopy can reveal the organization and dynamics of proteins and lipids within living cells at resolutions <200 nm. Parallel advances in molecular simulations provide near-atomic-resolution models of the dynamics of the organization of membranes of in vivo-like complexity. We explore the dynamics of proteins and lipids in crowded and complex plasma membrane models, thereby closing the gap in length and complexity between computations and experiments. Our simulations provide insights into the mutual interplay between lipids and proteins in determining mesoscale (20-100 nm) fluctuations of the bilayer, and in enabling oligomerization and clustering of membrane proteins.

  8. Systematic Tuning and Multifunctionalization of Covalent Organic Polymers for Enhanced Carbon Capture.

    PubMed

    Xiang, Zhonghua; Mercado, Rocio; Huck, Johanna M; Wang, Hui; Guo, Zhanhu; Wang, Wenchuan; Cao, Dapeng; Haranczyk, Maciej; Smit, Berend

    2015-10-21

    Porous covalent polymers are attracting increasing interest in the fields of gas adsorption, gas separation, and catalysis due to their fertile synthetic polymer chemistry, large internal surface areas, and ultrahigh hydrothermal stabilities. While precisely manipulating the porosities of porous organic materials for targeted applications remains challenging, we show how a large degree of diversity can be achieved in covalent organic polymers by incorporating multiple functionalities into a single framework, as is done for crystalline porous materials. Here, we synthesized 17 novel porous covalent organic polymers (COPs) with finely tuned porosities, a wide range of Brunauer-Emmett-Teller (BET) specific surface areas of 430-3624 m(2) g(-1), and a broad range of pore volumes of 0.24-3.50 cm(3) g(-1), all achieved by tailoring the length and geometry of building blocks. Furthermore, we are the first to successfully incorporate more than three distinct functional groups into one phase for porous organic materials, which has been previously demonstrated in crystalline metal-organic frameworks (MOFs). COPs decorated with multiple functional groups in one phase can lead to enhanced properties that are not simply linear combinations of the pure component properties. For instance, in the dibromobenzene-lined frameworks, the bi- and multifunctionalized COPs exhibit selectivities for carbon dioxide over nitrogen twice as large as any of the singly functionalized COPs. These multifunctionalized frameworks also exhibit a lower parasitic energy cost for carbon capture at typical flue gas conditions than any of the singly functionalized frameworks. Despite the significant improvement, these frameworks do not yet outperform the current state-of-art technology for carbon capture. Nonetheless, the tuning strategy presented here opens up avenues for the design of novel catalysts, the synthesis of functional sensors from these materials, and the improvement in the performance of

  9. Diels-Alder Trapping of Photochemically Generated o-Xylenols: Application in the Synthesis of Novel Organic Molecules and Polymers

    NASA Technical Reports Server (NTRS)

    Meador, Michael A.

    2003-01-01

    Bis(o-xylenol) equivalents are useful synthetic intermediates in the construction of polymers and hydroxyl substituted organic molecules which can organize by hydrogen bonded self-assembly into unique supramolecular structures. These polymers and supramolecular materials have potential use as coatings and thin films in aerospace, electronic and biomedical applications.

  10. Direct Patterning of Organic Functional Polymers through Conventional Photolithography and Noninvasive Cross-Link Agents.

    PubMed

    Squillaci, Marco A; Qiu, Feng; Aliprandi, Alessandro; Zhang, Fan; Feng, Xinliang; Samorì, Paolo

    2016-07-01

    A new technique for direct patterning of functional organic polymers using commercial photolithography setups with a minimal loss of the materials' performances is reported. This result is achieved through novel cross-link agents made by boron- and fluorine-containing heterocycles that can react between themselves upon UV- and white-light exposure.

  11. On the possible role of organic melanoidin polymers as matrices for prebiotic activity.

    PubMed

    Nissenbaum, A; Kenyon, D H; Oro, J

    1975-12-29

    One of the major diagenetic pathways of organic matter in recent sediments involves the condensation of cellular constituents, particularly amino acids and sugars, into insoluble melanoidin-type polymers. These polymers consist mainly of humic and fulvic acids and make up the major part of the organic carbon reservoir in recent sediments. We suggest that a similar set of reactions between abiotically formed amino acids and sugars, and more generally between aldehydes and amines, occurred on a large scale in the prebiotic hydrosphere. The rapid formation of this insoluble polymeric material would have removed the bulk of the dissolved organic carbon from the primitive oceans and would thus have prevented the formation of an "organic soup". Melanoidin polymers have several properties which make them attractive hypothetical precursors of contemporary oxidation-reduction coenzymes: 1. they contain heterocyclic nitrogen compounds similar to the nitrogenous bases; 2. they contain a high concentration of stable free radicals; and 3. they tend to concentrate those heavy metals which play prominent roles in contemporary enzymic redox processes. The prebiotic formation of similar polymers could, therefore, have provided the starting point for a basic class of biochemical reactions. We suggest that the prebiotic scenario involved chemical and protoenzymic reactions at the sediment-ocean interface in relatively shallow waters and under conditions not much different from those of the recent environment.

  12. A furan-containing conjugated polymer for high mobility ambipolar organic thin film transistors.

    PubMed

    Sonar, Prashant; Foong, Thelese Ru Bao; Singh, Samarendra P; Li, Yuning; Dodabalapur, Ananth

    2012-08-28

    Furan substituted diketopyrrolopyrrole (DBF) combined with benzothiadiazole based polymer semiconductor PDPP-FBF has been synthesized and evaluated as an ambipolar semiconductor in organic thin-film transistors. Hole and electron mobilities as high as 0.20 cm(2) V(-1) s(-1) and 0.56 cm(2) V(-1) s(-1), respectively, are achieved for PDPP-FBF.

  13. Synthesis of well dispersed polymer grafted metal-organic framework nanoparticles.

    PubMed

    Xie, K; Fu, Q; He, Y; Kim, J; Goh, S J; Nam, E; Qiao, G G; Webley, P A

    2015-11-01

    Novel polymer grafted metal-organic framework (MOF) nanoparticles were synthesized. The formed core/shell nanoparticles exhibit outstanding water dispersity and pH sensitivity, and show their catalytic effect for the reduction reaction of 4-nitrophenol (NP) to 4-aminophenol (AP) when loaded with Pd(0) catalyst.

  14. New electrostriction materials based on organic polymers: A review

    SciTech Connect

    Kochervinskii, V. V.

    2009-12-15

    The nature of very high electrostriction strains in modified fluorine-containing polymer ferroelectrics is considered. The main modification method is the irradiation of vinylidene fluoride (VDF) copolymers with trifluoroethylene (TrFE) by electrons with energies of several MeV. Such treatment leads to the transition of the ferroelectric phase to the relaxor state and paraelectric phase. These structural changes are caused by the formation of new functional groups in PVDF chains at radiolysis. The effect of the structure on the electrostriction strains is considered. It is shown that the increase in the electrostriction strain after irradiation is related to the increase in the amorphous phase fraction. This increased strain (all other factors being equal) in uniaxial films, in comparison with isotropic ones, indicates that the field of the anisotropic amorphous phase (mesomorphic state) regions plays an important role in the reaction. An analysis of the experimental data shows that the structural changes in the field (leading to electrostriction strains) are controlled to a great extent by the features of cooperative (segmental) mobility of amorphous phase chains.

  15. Organic aerogels: A new type of ultrastructured polymer

    SciTech Connect

    Pekala, R.W.; Alviso, C.T.; LeMay, J.D.

    1991-02-01

    Organic aerogels with different ultrastructures can be successfully synthesized from the aqueous sol-gel polymerization of (1) resorcinol with formaldehyde or (2) melamine with formaldehyde. In addition, RF aerogels can be pyrolyzed in an inert atmosphere to give vitreous carbon aerogels. The (resorcinol)/(sodium carbonate) ratio is the major variable in the RF polymerization while pH and acid type regulate the MF polymerization. Mechanical property, TEM, and surface area data provide evidence that organic aerogels are similar to their silica counterparts. Based upon these data, we are continuing to explore commonalities between inorganic and organic aerogels so that a universal model might be developed for the structure and properties of these unique materials. Such a model would have a major impact upon the materials science community by opening up new routes for the nanodesign of microporous materials with novel compositions, ultrastructures, and properties. 33 refs., 8 figs.

  16. Argon-oxygen atmospheric pressure plasma treatment on carbon fiber reinforced polymer for improved bonding

    NASA Astrophysics Data System (ADS)

    Chartosias, Marios

    Acceptance of Carbon Fiber Reinforced Polymer (CFRP) structures requires a robust surface preparation method with improved process controls capable of ensuring high bond quality. Surface preparation in a production clean room environment prior to applying adhesive for bonding would minimize risk of contamination and reduce cost. Plasma treatment is a robust surface preparation process capable of being applied in a production clean room environment with process parameters that are easily controlled and documented. Repeatable and consistent processing is enabled through the development of a process parameter window utilizing techniques such as Design of Experiments (DOE) tailored to specific adhesive and substrate bonding applications. Insight from respective plasma treatment Original Equipment Manufacturers (OEMs) and screening tests determined critical process factors from non-factors and set the associated factor levels prior to execution of the DOE. Results from mode I Double Cantilever Beam (DCB) testing per ASTM D 5528 [1] standard and DOE statistical analysis software are used to produce a regression model and determine appropriate optimum settings for each factor.

  17. Supramolecular organization in organic-inorganic heterogeneous hybrid catalysts formed from polyoxometalate and poly(ampholyte) polymer.

    PubMed

    Raj, Gijo; Swalus, Colas; Guillet, Alain; Devillers, Michel; Nysten, Bernard; Gaigneaux, Eric M

    2013-04-01

    Hybridization of polyoxometalates (POMs) via the formation of an organic-inorganic association constitutes a new route to develop a heterogeneous POM catalyst with tunable functionality imparted through supramolecular assembly. Herein, we report on strategies to obtain tunable well-defined supramolecular architectures of an organic-inorganic heterogeneous hybrid catalyst formed by the association of a hydrophobically substituted polyampholyte copolymer (poly N, N-diallyl-N-hexylamine-alt-maleic acid) and phosphotungstic acid (H3PW12O40) POMs. The self-assembling property of the initial polyampholyte copolymer matrix is modulated by controlling the pH of the hybridization solution. When deposited on a mica surface, isolated, long and extended polymer chains are formed under basic conditions (pH 7.9), while globular or coiled structures are formed under acidic conditions (pH 2). The supramolecular assembly of the POM-polymer hybrid is found to be directed by the type and quantities of charges present on the polyampholyte copolymer, which themselves depend on the pH conditions. The hypothesis is that the Keggin type [PW12O40](3-) anions, which have a size of ~1 nm, electrostatically bind to the positive charge sites of the polymer backbone. The hybrid material stabilized at pH 5.3 consists of POM-decorated polymer chains. Statistical analysis of distances between pairs of POM entities show narrow density distributions, suggesting that POM entities are attached to the polymer chains with a high level of order. Conversely, under acidic conditions (pH 2), the hybrid shows the formation of a core-shell type of structure. The strategies reported here, to tune the supramolecular assembly of organic-inorganic hybrid materials, are highly valuable for the design and a more rational utilization of POM heterogeneous catalysts in several chemical transformations. PMID:23480273

  18. Supramolecular organization in organic-inorganic heterogeneous hybrid catalysts formed from polyoxometalate and poly(ampholyte) polymer.

    PubMed

    Raj, Gijo; Swalus, Colas; Guillet, Alain; Devillers, Michel; Nysten, Bernard; Gaigneaux, Eric M

    2013-04-01

    Hybridization of polyoxometalates (POMs) via the formation of an organic-inorganic association constitutes a new route to develop a heterogeneous POM catalyst with tunable functionality imparted through supramolecular assembly. Herein, we report on strategies to obtain tunable well-defined supramolecular architectures of an organic-inorganic heterogeneous hybrid catalyst formed by the association of a hydrophobically substituted polyampholyte copolymer (poly N, N-diallyl-N-hexylamine-alt-maleic acid) and phosphotungstic acid (H3PW12O40) POMs. The self-assembling property of the initial polyampholyte copolymer matrix is modulated by controlling the pH of the hybridization solution. When deposited on a mica surface, isolated, long and extended polymer chains are formed under basic conditions (pH 7.9), while globular or coiled structures are formed under acidic conditions (pH 2). The supramolecular assembly of the POM-polymer hybrid is found to be directed by the type and quantities of charges present on the polyampholyte copolymer, which themselves depend on the pH conditions. The hypothesis is that the Keggin type [PW12O40](3-) anions, which have a size of ~1 nm, electrostatically bind to the positive charge sites of the polymer backbone. The hybrid material stabilized at pH 5.3 consists of POM-decorated polymer chains. Statistical analysis of distances between pairs of POM entities show narrow density distributions, suggesting that POM entities are attached to the polymer chains with a high level of order. Conversely, under acidic conditions (pH 2), the hybrid shows the formation of a core-shell type of structure. The strategies reported here, to tune the supramolecular assembly of organic-inorganic hybrid materials, are highly valuable for the design and a more rational utilization of POM heterogeneous catalysts in several chemical transformations.

  19. Organic chemistry meets polymers, nanoscience, therapeutics and diagnostics.

    PubMed

    Rotello, Vincent M

    2016-01-01

    The atom-by-atom control provided by synthetic organic chemistry presents a means of generating new functional nanomaterials with great precision. Bringing together these two very disparate skill sets is, however, quite uncommon. This autobiographical review provides some insight into how my program evolved, as well as giving some idea of where we are going. PMID:27559417

  20. Organic chemistry meets polymers, nanoscience, therapeutics and diagnostics

    PubMed Central

    2016-01-01

    Summary The atom-by-atom control provided by synthetic organic chemistry presents a means of generating new functional nanomaterials with great precision. Bringing together these two very disparate skill sets is, however, quite uncommon. This autobiographical review provides some insight into how my program evolved, as well as giving some idea of where we are going. PMID:27559417

  1. Organic chemistry meets polymers, nanoscience, therapeutics and diagnostics.

    PubMed

    Rotello, Vincent M

    2016-01-01

    The atom-by-atom control provided by synthetic organic chemistry presents a means of generating new functional nanomaterials with great precision. Bringing together these two very disparate skill sets is, however, quite uncommon. This autobiographical review provides some insight into how my program evolved, as well as giving some idea of where we are going.

  2. Colloidal crystal based plasma polymer patterning to control Pseudomonas aeruginosa attachment to surfaces.

    PubMed

    Pingle, Hitesh; Wang, Peng-Yuan; Thissen, Helmut; McArthur, Sally; Kingshott, Peter

    2015-12-02

    Biofilm formation on medical implants and subsequent infections are a global problem. A great deal of effort has focused on developing chemical contrasts based on micro- and nanopatterning for studying and controlling cells and bacteria at surfaces. It has been known that micro- and nanopatterns on surfaces can influence biomolecule adsorption, and subsequent cell and bacterial adhesion. However, less focus has been on precisely controlling patterns to study the initial bacterial attachment mechanisms and subsequently how the patterning influences the role played by biomolecular adsorption on biofilm formation. In this work, the authors have used colloidal self-assembly in a confined area to pattern surfaces with colloidal crystals and used them as masks during allylamine plasma polymer (AAMpp) deposition to generate highly ordered patterns from the micro- to the nanoscale. Polyethylene glycol (PEG)-aldehyde was grafted to the plasma regions via "cloud point" grafting to prevent the attachment of bacteria on the plasma patterned surface regions, thereby controlling the adhesive sites by choice of the colloidal crystal morphology. Pseudomonas aeruginosa was chosen to study the bacterial interactions with these chemically patterned surfaces. Scanning electron microscope, x-ray photoelectron spectroscopy (XPS), atomic force microscopy, and epifluorescence microscopy were used for pattern characterization, surface chemical analysis, and imaging of attached bacteria. The AAMpp influenced bacterial attachment because of the amine groups displaying a positive charge. XPS results confirm the successful grafting of PEG on the AAMpp surfaces. The results showed that PEG patterns can be used as a surface for bacterial patterning including investigating the role of biomolecular patterning on bacterial attachment. These types of patterns are easy to fabricate and could be useful in further applications in biomedical research.

  3. Relationship between band gap and bond length alternation in organic conjugated polymers

    NASA Astrophysics Data System (ADS)

    Bredas, J. L.

    1985-04-01

    A description is given of calculations of the evolution of the band gap as a function of geometry in conjugated polymers based on aromatic rings; polyparaphenylene, polypyrrole, polythiophene. The results demonstrate that the gap decreases as a function of increasing quinoid character of the backbone and is thus not minimal in the case of zero bond length alternation, in contrast to the situation found in polyacetylene-like compounds. The consequences of these results are stressed for the understanding of the effects of doping and for the design of new organic polymers with small gaps.

  4. Effect of fractal silver electrodes on charge collection and light distribution in semiconducting organic polymer films

    SciTech Connect

    Chamousis, RL; Chang, LL; Watterson, WJ; Montgomery, RD; Taylor, RP; Moule, AJ; Shaheen, SE; Ilan, B; van de Lagemaat, J; Osterloh, FE

    2014-08-21

    Living organisms use fractal structures to optimize material and energy transport across regions of differing size scales. Here we test the effect of fractal silver electrodes on light distribution and charge collection in organic semiconducting polymer films made of P3HT and PCBM. The semiconducting polymers were deposited onto electrochemically grown fractal silver structures (5000 nm x 500 nm; fractal dimension of 1.71) with PEDOT:PSS as hole-selective interlayer. The fractal silver electrodes appear black due to increased horizontal light scattering, which is shown to improve light absorption in the polymer. According to surface photovoltage spectroscopy, fractal silver electrodes outperform the flat electrodes when the BHJ film thickness is large (>400 nm, 0.4 V photovoltage). Photocurrents of up to 200 microamperes cm(-2) are generated from the bulk heterojunction (BHJ) photoelectrodes under 435 nm LED (10-20 mW cm(-2)) illumination in acetonitrile solution containing 0.005 M ferrocenium hexafluorophosphate as the electron acceptor. The low IPCE values (0.3-0.7%) are due to slow electron transfer to ferrocenium ion and due to shunting along the large metal-polymer interface. Overall, this work provides an initial assessment of the potential of fractal electrodes for organic photovoltaic cells.

  5. Lipophilic polyelectrolyte gels as super-absorbent polymers for nonpolar organic solvents

    NASA Astrophysics Data System (ADS)

    Ono, Toshikazu; Sugimoto, Takahiro; Shinkai, Seiji; Sada, Kazuki

    2007-06-01

    Polyelectrolyte gels that are known as super-absorbent polymers swell and absorb water up to several hundred times their dried weights and have become ubiquitous and indispensable materials in many applications. Their superior swelling abilities originate from the electrostatic repulsion between the charges on the polymer chains and the osmotic imbalance between the interior and exterior of the gels. However, no super-absorbent polymers for volatile organic compounds (VOCs), and especially for nonpolar organic solvents (ɛ<10) have been reported, because common polyelectrolyte gels collapse in such solvents owing to the formation of a higher number of aggregates of ions and ion pairs. Here, we report that a novel class of polyelectrolyte gels bearing tetra-alkylammonium tetraphenylborate as a lipophilic and bulky ionic group swell in some nonpolar organic solvents up to 500 times their dry size. Dissociation of the ionic groups even in low-dielectric media (3<ɛ<10) enhances the swelling ability by expansion of the polymer networks. This expands the potential of polyelectrolytes that have been used only in aqueous solutions or highly polar solvents, and provides soft materials that swell in a variety of media. These materials could find applications as protective barriers for VOCs spilled in the environment and as absorbents for waste oil.

  6. Research on the electronic and optical properties of polymer and other organic molecular thin films

    SciTech Connect

    1997-02-01

    The main goal of the work is to find materials and methods of optimization of organic layered electroluminescent cells and to study such properties of polymers and other organic materials that can be used in various opto-electronic devices. The summary of results obtained during the first year of work is presented. They are: (1) the possibility to produce electroluminescent cells using a vacuum deposition photoresist technology for commercial photoresists has been demonstrated; (2) the idea to replace the polyaryl polymers by other polymers with weaker hole conductivity for optimization of electroluminescent cells with ITO-Al electrodes has been suggested. The goal is to obtain amorphous processable thin films of radiative recombination layers in electroluminescent devices; (3) procedures of preparation of high-quality vacuum-deposited poly (p-phenylene) (PPP) films on various substrates have been developed; (4) it was found for the first time that the fluorescence intensity of PPP films depends on the degree of polymerization; (5) the role of interfaces between organic compounds, on one side, and metals or semiconductors, on the other side, has been studied and quenching of the fluorescence caused by semiconductor layer in thin sandwiches has been observed; (6) studies of the dynamics of photoexcitations revealed the exciton self-trapping in quasi-one-dimensional aggregates; and (7) conditions for preparation of highly crystalline fullerene C{sub 60} films by vacuum deposition have been found. Composites of C{sub 60} with conjugated polymers have been prepared.

  7. Nanoparticle surface modification by amphiphilic polymers in aqueous media: role of polar organic solvents.

    PubMed

    Sarkar, Biswajit; Venugopal, Vinithra; Bodratti, Andrew M; Tsianou, Marina; Alexandridis, Paschalis

    2013-05-01

    We investigate the role of three polar organic solvents (dimethyl formamide (DMF), dimethyl sulfoxide (DMSO), and glycerol) on the interfacial behavior of Pluronic P105 poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) block copolymers on protonated silica nanoparticles in an aqueous dispersion. The polymer adsorption and self-assembly have been assessed from critical surface micelle concentration (csmc, measured by pyrene fluorescence spectroscopy) and adsorbed layer thickness (measured by capillary viscometry) data. Above its csmc, PEO-PPO-PEO block copolymers form hydrophobic domains on the nanoparticle surface. Below a critical concentration in water (known as critical displacer concentration, cdc), organic solvents act as displacers (molecules that can displace adsorbed polymer from a solid surface). The critical displacer concentration is obtained from the csmc and the polymer adsorbed layer thickness data. The cdc is found to be dependent on both the amount of nanoparticles present in the system as well as the nature of the displacer. Below the cdc, the csmc increases and the adsorbed polymer layer thickness decreases with increasing organic solvent concentration. Interfacial free energy calculations suggest that DMF, DMSO, and glycerol can adsorb onto the silica particles by displacing adsorbed PEO. These calculations are consistent with the experimental results in that, as a displacer, glycerol is the most effective and DMF is the least effective. Above the cdc, the influence of glycerol or DMSO on csmc is opposite to that of DMF which is attributed to the cosolvent effect.

  8. Parametric study of Al and Al 2O 3 ceramic coatings deposited by air plasma spray onto polymer substrate

    NASA Astrophysics Data System (ADS)

    Guanhong, Sun; Xiaodong, He; Jiuxing, Jiang; Yue, Sun

    2011-06-01

    Aluminum and ceramic (Al 2O 3) coatings were deposited onto the polymer substrate by air plasma spray (APS) to improve the mechanical properties of the polymer surface. The effect of spray parameters (current and spray distance in this paper) on the phase composition, microstructure and mechanical properties was investigated. Shear adhesion strength between the coatings and the substrates was also examined. The results indicate that the deposition parameters have a significant effect on the phase composition, microstructure and mechanical properties of as-spayed coatings. The maximum shear adhesion strength of the bond coats was 5.21 MPa with the current of 180 A and 190 mm spray distance.

  9. Origin of organic matter in the early solar system. VII - The organic polymer in carbonaceous chondrites

    NASA Technical Reports Server (NTRS)

    Hayatsu, R.; Matsuoka, S.; Anders, E.; Scott, R. G.; Studier, M. H.

    1977-01-01

    Degradation techniques, including pyrolysis, depolymerization, and oxidation, were used to study the insoluble polymer from the Murchison C2 chondrite. Oxidation with Cr2O7(2-) or O2/UV led to the identification of 15 aromatic ring systems. Of 11 aliphatic acids identified, three dicarboxylic acids presumably came from hydroaromatic portions of the polymer, whereas eight monocarboxylic acids probably derive from bridging groups or ring substituents. Depolymerization with CF3COO4 yielded some of the same ring systems, as well as alkanes (C1 through C8) and alkenes (C2 through C8), alkyl (C1 through C5) benzenes and naphthalenes, and methyl- or dimethyl -indene, -indane, -phenol, -pyrrole, and -pyridine. All these compounds were detected below 200 C, and are therefore probably indigenous constituents. The properties of the meteoritic polymer were compared with the properties of a synthetic polymer produced by the Fischer-Tropsch reaction. It is suggested that the meteoritic polymer was also produced by surface catalysis.

  10. Dynamics of intracellular polymers in enhanced biological phosphorus removal processes under different organic carbon concentrations.

    PubMed

    Xing, Lizhen; Ren, Li; Tang, Bo; Wu, Guangxue; Guan, Yuntao

    2013-01-01

    Enhanced biological phosphorus removal (EBPR) may deteriorate or fail during low organic carbon loading periods. Polyphosphate accumulating organisms (PAOs) in EBPR were acclimated under both high and low organic carbon conditions, and then dynamics of polymers in typical cycles, anaerobic conditions with excess organic carbons, and endogenous respiration conditions were examined. After long-term acclimation, it was found that organic loading rates did not affect the yield of PAOs and the applied low organic carbon concentrations were advantageous for the enrichment of PAOs. A low influent organic carbon concentration induced a high production of extracellular carbohydrate. During both anaerobic and aerobic endogenous respirations, when glycogen decreased to around 80 ± 10 mg C per gram of volatile suspended solids, PAOs began to utilize polyphosphate significantly. Regressed by the first-order reaction model, glycogen possessed the highest degradation rate and then was followed by polyphosphate, while biomass decay had the lowest degradation rate.

  11. Enhanced Molecular Packing of a Conjugated Polymer with High Organic Thermoelectric Power Factor.

    PubMed

    Ma, Wei; Shi, Ke; Wu, Yang; Lu, Zuo-Yu; Liu, Han-Yu; Wang, Jie-Yu; Pei, Jian

    2016-09-21

    The detailed relationship between film morphology and the performance of solution processed n-type organic thermoelectric (TE) devices is investigated. It is interesting to find that the better ordered molecular packing of n-type polymer can be achieved by adding a small fraction of dopant molecules, which is not observed before. The better ordered structure will be favorable for the charge carrier mobility. Meanwhile, dopant molecules improve free carrier concentration via doping reaction. As a result, a significantly enhanced electrical conductivity (12 S cm(-1)) and power factor (25.5 μW m(-1) K(-2)) of TE devices are obtained. Furthermore, the phase separation of conjugated polymer/dopants is observed for the first time with resonant soft X-ray scattering. Our results indicate that the miscibility of conjugated polymers and dopants plays an important role on controlling the morphology and doping efficiency of TE devices.

  12. Enhanced ethylene separation and plasticization resistance in polymer membranes incorporating metal-organic framework nanocrystals

    NASA Astrophysics Data System (ADS)

    Bachman, Jonathan E.; Smith, Zachary P.; Li, Tao; Xu, Ting; Long, Jeffrey R.

    2016-08-01

    The implementation of membrane-based separations in the petrochemical industry has the potential to reduce energy consumption significantly relative to conventional separation processes. Achieving this goal, however, requires the development of new membrane materials with greater selectivity, permeability and stability than available at present. Here, we report composite materials consisting of nanocrystals of metal-organic frameworks dispersed within a high-performance polyimide, which can exhibit enhanced selectivity for ethylene over ethane, greater ethylene permeability and improved membrane stability. Our results suggest that framework-polymer interactions reduce chain mobility of the polymer while simultaneously boosting membrane separation performance. The increased stability, or plasticization resistance, is expected to improve membrane utility under real process conditions for petrochemical separations and natural gas purification. Furthermore, this approach can be broadly applied to numerous polymers that encounter aggressive environments, potentially making gas separations possible that were previously inaccessible to membranes.

  13. Enhanced Molecular Packing of a Conjugated Polymer with High Organic Thermoelectric Power Factor.

    PubMed

    Ma, Wei; Shi, Ke; Wu, Yang; Lu, Zuo-Yu; Liu, Han-Yu; Wang, Jie-Yu; Pei, Jian

    2016-09-21

    The detailed relationship between film morphology and the performance of solution processed n-type organic thermoelectric (TE) devices is investigated. It is interesting to find that the better ordered molecular packing of n-type polymer can be achieved by adding a small fraction of dopant molecules, which is not observed before. The better ordered structure will be favorable for the charge carrier mobility. Meanwhile, dopant molecules improve free carrier concentration via doping reaction. As a result, a significantly enhanced electrical conductivity (12 S cm(-1)) and power factor (25.5 μW m(-1) K(-2)) of TE devices are obtained. Furthermore, the phase separation of conjugated polymer/dopants is observed for the first time with resonant soft X-ray scattering. Our results indicate that the miscibility of conjugated polymers and dopants plays an important role on controlling the morphology and doping efficiency of TE devices. PMID:27579521

  14. Enhanced ethylene separation and plasticization resistance in polymer membranes incorporating metal-organic framework nanocrystals.

    PubMed

    Bachman, Jonathan E; Smith, Zachary P; Li, Tao; Xu, Ting; Long, Jeffrey R

    2016-08-01

    The implementation of membrane-based separations in the petrochemical industry has the potential to reduce energy consumption significantly relative to conventional separation processes. Achieving this goal, however, requires the development of new membrane materials with greater selectivity, permeability and stability than available at present. Here, we report composite materials consisting of nanocrystals of metal-organic frameworks dispersed within a high-performance polyimide, which can exhibit enhanced selectivity for ethylene over ethane, greater ethylene permeability and improved membrane stability. Our results suggest that framework-polymer interactions reduce chain mobility of the polymer while simultaneously boosting membrane separation performance. The increased stability, or plasticization resistance, is expected to improve membrane utility under real process conditions for petrochemical separations and natural gas purification. Furthermore, this approach can be broadly applied to numerous polymers that encounter aggressive environments, potentially making gas separations possible that were previously inaccessible to membranes.

  15. Natural polymer crystals of hydrocarbons as models of prebiological organisms

    NASA Astrophysics Data System (ADS)

    Yushkin, N. P.

    1996-09-01

    Among solid hydrocarbons (bitumens) widely spread in the lithosphere, forms representing various degrees of molecular ordering, like globules, fibers, quasicrystals, fullerenes, etc., have been recently discovered. The most perfect ones are original fibrous, spiral and spherical crystals of kerite found in chamber pegmatities of Korosten granitoid massive in the Ukraine. The age of the pegmatites is 1,700 million years, they originated at a depth of 1.5-2 km. The kerite composition is C 491H 386O 87S(N). Kerite crystallization took place in a chamber of a pegmatite body in a steam-and-gas environment at T = 500 dash280°C and P = 20 MPa from hydrocarbon gases of igneous origin in the presence of catalysts. The fibrous kerite's structure and properties are very similar to those of simple organisms. Its chemical composition, for example, is nearly identical to that of a protein. The presence of a large number of minerals in association with fibrous kerite, including zeolite (natrolite) acting as a membrane, abundant release of hydrocarbon gases on heating, complex morphology and the presence of both internal and external actively growing surfaces account for a much more complex (in comparison with ionic inorganic crystals) "life" for fibrous kerite crystals and stimulate an evolution of various metabolic processes. The finding of hydrocarbon crystals with a composition, form and structure similar to living organisms is a convincing confirmation of the conception of "crystallization of life" that occurred under the same conditions as crystallization of minerals.

  16. Effects of Deposition Plasma Power on Properties of Low Dielectric-Constant Plasma Polymer Films Deposited Using Hexamethyldisiloxane and 3,3-Dimethyl-1-butene Precursors

    NASA Astrophysics Data System (ADS)

    Lee, Sungwoo; Woo, Jihyung; Nam, Eunkyoung; Jung, Donggeun; Yang, Jaeyoung; Chae, Heeyeop; Kim, Hyoungsub

    2009-10-01

    We investigated the effects of deposition plasma power on the properties of plasma polymer films deposited by plasma-enhanced chemical vapor deposition using a mixture of hexamethyldisiloxane and 3,3-dimethyl-1-butene as the precursor, which are referred to as plasma polymerized hexamethyldisiloxane:3,3-dimethyl-1-butene (PPHMDSO:DMB) films. As the deposition plasma power was increased from 15 to 60 W, the relative dielectric constants k of PPHMDSO:DMB films, increased from 2.67 to 3.19. After annealing at 450 °C, the films deposited at a deposition plasma power of 15-60 W showed k values of 2.27-2.64. With increased deposition plasma power, the as-deposited and annealed films showed increased values of hardness and Young's modulus. For as-deposited films, deposited at a plasma power of 15-60 W, the films showed a hardness of 0.13-2.0 GPa, and a modulus of 2.25-17.27 GPa. Annealed films, deposited at a plasma power of 15-60 W, showed a hardness of 0.05-2.07 GPa and a modulus of 1.66-14.4 GPa. The change in the k value and hardness of plasma polymer films as a function of deposition plasma power was correlated with fourier transform infrared (FT-IR) absorption peaks of C-Hx, Si-CH3, and Si-O related groups. The as-deposited and annealed PPHMDSO:DMB films showed decreased intensities of C-Hx and Si-CH3 peaks as the deposition plasma power increased. The reduction in the dielectric constant after annealing is mainly due to hydrocarbon removal in the film. Deconvolution of Si-CH3 bending peaks of PPHMDSO:DMB films was performed to relate mechanical properties to chemical structures. The relative oxygen content in the O-Si-(CH3)x structure is analyzed in detail. Improvements in hardness and modulus of our films are attributed to an increased amount of O3Si-(CH3) in the Si-CH3 structure.

  17. Theory of self-organized critical transport in tokamak plasmas

    SciTech Connect

    Kishimoto, Y.; Tajima, T.; Horton, W.; LeBrun, M.J.; Kim, J.Y. |

    1995-07-01

    A theoretical and computational study of the ion temperature gradient and {eta}{sub i} instabilities in tokamak plasmas has been carried out. In toroidal geometry the modes have a radially extended structure and their eigenfrequencies are constant over many rational surfaces that are coupled through toroidicity. These nonlocal properties of the ITG modes impose strong constraint on the drift mode fluctuations and the amciated transport, showing a self-organized characteristic. As any significant deviation away from marginal stability causes rapid temperature relaxation and intermittent bursts, the modes hover near marginality and exhibit strong kinetic characteristics. As a result, the temperature relaxation is self-semilar and nonlocal, leading to a radially increasing heat diffusivity. The nonlocal transport leads to the Bohm-like diffusion scaling. The heat input regulates the deviation of the temperature gradient away from marginality. The obtained transport scalings and properties are globally consistent with experimental observations of L-mode charges.

  18. Metal-Organic Polyhedral Core as a Versatile Scaffold for Divergent and Convergent Star Polymer Synthesis.

    PubMed

    Hosono, Nobuhiko; Gochomori, Mika; Matsuda, Ryotaro; Sato, Hiroshi; Kitagawa, Susumu

    2016-05-25

    We herein report the divergent and convergent synthesis of coordination star polymers (CSP) by using metal-organic polyhedrons (MOPs) as a multifunctional core. For the divergent route, copper-based great rhombicuboctahedral MOPs decorated with dithiobenzoate or trithioester chain transfer groups at the periphery were designed. Subsequent reversible addition-fragmentation chain transfer (RAFT) polymerization of monomers mediated by the MOPs gave star polymers, in which 24 polymeric arms were grafted from the MOP core. On the other hand, the convergent route provided identical CSP architectures by simple mixing of a macroligand and copper ions. Isophthalic acid-terminated polymers (so-called macroligands) immediately formed the corresponding CSPs through a coordination reaction with copper(II) ions. This convergent route enabled us to obtain miktoarm CSPs with tunable chain compositions through ligand mixing alone. This powerful method allows instant access to a wide variety of multicomponent star polymers that conventionally have required highly skilled and multistep syntheses. MOP-core CSPs are a new class of star polymer that can offer a design strategy for highly processable porous soft materials by using coordination nanocages as a building component.

  19. Microporous organic polymer-based lithium ion batteries with improved rate performance and energy density

    NASA Astrophysics Data System (ADS)

    Zhang, Chong; Yang, Xiao; Ren, Wenfeng; Wang, Yanhong; Su, Fabing; Jiang, Jia-Xing

    2016-06-01

    Microporous organic polymers with triphenylamine segments were employed as cathode materials for lithium ion batteries. YPTPA with the highest surface area exhibits a discharge plateau at ∼3.6 V vs. Li/Li+, an initial Coulombic efficiency of 96.8% at 50 mA g-1 and a discharge capacity of 105.7 mAh g-1 at 200 mA g-1. Compared to the homo-coupled polymer of OPTPA with relatively low surface area (66 m2 g-1), SPTPA and YPTPA with higher surface area (544 and 1557 m2 g-1, respectively) show enhanced rate performances and energy densities. YPTPA can deliver 97.6 mAh g-1 within less than 3 min at high rate of 2000 mA g-1 and the energy density of 334 Wh kg-1 under an ultrahigh power density of 6816 W kg-1, while OPTPA only presents 48.2 mAh g-1 at 2000 mA g-1 with an energy density of 155 Wh kg-1 under 6414 W kg-1. The great improvement in electrochemical properties of SPTPA and YPTPA demonstrates that increasing surface area of polymer cathodes by interweaving the redox-active units into microporous polymer skeleton is an efficient way to develop advanced polymer cathode materials with outstanding electrochemical performance.

  20. Metal-Organic Polyhedral Core as a Versatile Scaffold for Divergent and Convergent Star Polymer Synthesis.

    PubMed

    Hosono, Nobuhiko; Gochomori, Mika; Matsuda, Ryotaro; Sato, Hiroshi; Kitagawa, Susumu

    2016-05-25

    We herein report the divergent and convergent synthesis of coordination star polymers (CSP) by using metal-organic polyhedrons (MOPs) as a multifunctional core. For the divergent route, copper-based great rhombicuboctahedral MOPs decorated with dithiobenzoate or trithioester chain transfer groups at the periphery were designed. Subsequent reversible addition-fragmentation chain transfer (RAFT) polymerization of monomers mediated by the MOPs gave star polymers, in which 24 polymeric arms were grafted from the MOP core. On the other hand, the convergent route provided identical CSP architectures by simple mixing of a macroligand and copper ions. Isophthalic acid-terminated polymers (so-called macroligands) immediately formed the corresponding CSPs through a coordination reaction with copper(II) ions. This convergent route enabled us to obtain miktoarm CSPs with tunable chain compositions through ligand mixing alone. This powerful method allows instant access to a wide variety of multicomponent star polymers that conventionally have required highly skilled and multistep syntheses. MOP-core CSPs are a new class of star polymer that can offer a design strategy for highly processable porous soft materials by using coordination nanocages as a building component. PMID:27119553

  1. Theory of self-organized critical transport in tokamak plasmas

    SciTech Connect

    Kishimoto, Y.; Tajima, T.; Horton, W.; LeBrun, M.J.; Kim, J.Y.

    1996-04-01

    A theoretical and computational study of the ion temperature gradient (ITG) and {eta}{sub {ital i}} instabilities in tokamak plasmas has been carried out. In a toroidal geometry the modes have a radially extended structure and their eigenfrequencies are constant over many rational surfaces that are coupled through toroidicity. These nonlocal properties of the ITG modes impose a strong constraint on the drift mode fluctuations and the associated transport, showing self-organized criticality. As any significant deviation away from marginal stability causes rapid temperature relaxation and intermittent bursts, the modes hover near marginality and exhibit strong kinetic characteristics. As a result of this, the temperature relaxation is self-similar and nonlocal, leading to radially increasing heat diffusivity. The nonlocal transport leads to Bohm-like diffusion scaling. Heat input regulates the deviation of the temperature gradient away from marginality. We present a critical gradient transport model that describes such a self-organized relaxed state. Some of the important aspects in tokamak transport like Bohm diffusion, near marginal stability, radially increasing fluctuation energy and heat diffusivity, intermittency of the wave excitation, and resilient tendency of the plasma profile can be described by this model, and these prominent features are found to belong to one physical category that originates from the radially extended nonlocal drift modes. The obtained transport properties and scalings are globally consistent with experimental observations of low confinement mode (L-mode) discharges. The nonlocal modes can be disintegrated into smaller radial islands by a poloidal shear flow, suggesting that the transport changes from Bohm-like to near gyro-Bohm. {copyright} {ital 1996 American Institute of Physics.}

  2. Moisture barrier properties of thin organic-inorganic multilayers prepared by plasma-enhanced ALD and CVD in one reactor

    NASA Astrophysics Data System (ADS)

    Bülow, Tim; Gargouri, Hassan; Siebert, Mirko; Rudolph, Rolf; Johannes, Hans-Hermann; Kowalsky, Wolfgang

    2014-05-01

    A widely used application of the atomic layer deposition (ALD) and chemical vapour deposition (CVD) methods is the preparation of permeation barrier layers against water vapour. Especially in the field of organic electronics, these films are highly demanded as such devices are very sensitive to moisture and oxygen. In this work, multilayers of aluminium oxide (AlO x ) and plasma polymer (PP) were coated on polyethylene naphthalate substrates by plasma-enhanced ALD and plasma-enhanced CVD at 80℃ in the same reactor, respectively. As precursor, trimethylaluminium was used together with oxygen radicals in order to prepare AlO x , and benzene served as precursor to deposit the PP. This hybrid structure allows the decoupling of defects between the single AlO x layers and extends the permeation path for water molecules towards the entire barrier film. Furthermore, the combination of two plasma techniques in a single reactor system enables short process times without vacuum breaks. Single aluminium oxide films by plasma-enhanced ALD were compared to thermally grown layers and showed a significantly better barrier performance. The water vapour transmission rate (WVTR) was determined by means of electrical calcium tests. For a multilayer with 3.5 dyads of 25-nm AlO x and 125-nm PP, a WVTR of 1.2 × 10 -3 g m -2 d -1 at 60℃ and 90% relative humidity could be observed.

  3. Moisture barrier properties of thin organic-inorganic multilayers prepared by plasma-enhanced ALD and CVD in one reactor.

    PubMed

    Bülow, Tim; Gargouri, Hassan; Siebert, Mirko; Rudolph, Rolf; Johannes, Hans-Hermann; Kowalsky, Wolfgang

    2014-01-01

    A widely used application of the atomic layer deposition (ALD) and chemical vapour deposition (CVD) methods is the preparation of permeation barrier layers against water vapour. Especially in the field of organic electronics, these films are highly demanded as such devices are very sensitive to moisture and oxygen. In this work, multilayers of aluminium oxide (AlO x ) and plasma polymer (PP) were coated on polyethylene naphthalate substrates by plasma-enhanced ALD and plasma-enhanced CVD at 80â"ƒ in the same reactor, respectively. As precursor, trimethylaluminium was used together with oxygen radicals in order to prepare AlO x , and benzene served as precursor to deposit the PP. This hybrid structure allows the decoupling of defects between the single AlO x layers and extends the permeation path for water molecules towards the entire barrier film. Furthermore, the combination of two plasma techniques in a single reactor system enables short process times without vacuum breaks. Single aluminium oxide films by plasma-enhanced ALD were compared to thermally grown layers and showed a significantly better barrier performance. The water vapour transmission rate (WVTR) was determined by means of electrical calcium tests. For a multilayer with 3.5 dyads of 25-nm AlO x and 125-nm PP, a WVTR of 1.2 × 10 (-3) gm (-2) d (-1) at 60â"ƒ and 90% relative humidity could be observed.

  4. Moisture barrier properties of thin organic-inorganic multilayers prepared by plasma-enhanced ALD and CVD in one reactor

    PubMed Central

    2014-01-01

    A widely used application of the atomic layer deposition (ALD) and chemical vapour deposition (CVD) methods is the preparation of permeation barrier layers against water vapour. Especially in the field of organic electronics, these films are highly demanded as such devices are very sensitive to moisture and oxygen. In this work, multilayers of aluminium oxide (AlO x ) and plasma polymer (PP) were coated on polyethylene naphthalate substrates by plasma-enhanced ALD and plasma-enhanced CVD at 80℃ in the same reactor, respectively. As precursor, trimethylaluminium was used together with oxygen radicals in order to prepare AlO x , and benzene served as precursor to deposit the PP. This hybrid structure allows the decoupling of defects between the single AlO x layers and extends the permeation path for water molecules towards the entire barrier film. Furthermore, the combination of two plasma techniques in a single reactor system enables short process times without vacuum breaks. Single aluminium oxide films by plasma-enhanced ALD were compared to thermally grown layers and showed a significantly better barrier performance. The water vapour transmission rate (WVTR) was determined by means of electrical calcium tests. For a multilayer with 3.5 dyads of 25-nm AlO x and 125-nm PP, a WVTR of 1.2 × 10 −3 gm−2d−1 at 60℃ and 90% relative humidity could be observed. PMID:24936155

  5. Moisture barrier properties of thin organic-inorganic multilayers prepared by plasma-enhanced ALD and CVD in one reactor.

    PubMed

    Bülow, Tim; Gargouri, Hassan; Siebert, Mirko; Rudolph, Rolf; Johannes, Hans-Hermann; Kowalsky, Wolfgang

    2014-01-01

    A widely used application of the atomic layer deposition (ALD) and chemical vapour deposition (CVD) methods is the preparation of permeation barrier layers against water vapour. Especially in the field of organic electronics, these films are highly demanded as such devices are very sensitive to moisture and oxygen. In this work, multilayers of aluminium oxide (AlO x ) and plasma polymer (PP) were coated on polyethylene naphthalate substrates by plasma-enhanced ALD and plasma-enhanced CVD at 80â"ƒ in the same reactor, respectively. As precursor, trimethylaluminium was used together with oxygen radicals in order to prepare AlO x , and benzene served as precursor to deposit the PP. This hybrid structure allows the decoupling of defects between the single AlO x layers and extends the permeation path for water molecules towards the entire barrier film. Furthermore, the combination of two plasma techniques in a single reactor system enables short process times without vacuum breaks. Single aluminium oxide films by plasma-enhanced ALD were compared to thermally grown layers and showed a significantly better barrier performance. The water vapour transmission rate (WVTR) was determined by means of electrical calcium tests. For a multilayer with 3.5 dyads of 25-nm AlO x and 125-nm PP, a WVTR of 1.2 × 10 (-3) gm (-2) d (-1) at 60â"ƒ and 90% relative humidity could be observed. PMID:24936155

  6. Polymer models of the organization of chromosomes in the nucleus of cells

    NASA Astrophysics Data System (ADS)

    Chiariello, Andrea Maria; Bianco, Simona; Piccolo, Andrea; Annunziatella, Carlo; Barbieri, Mariano; Pombo, Ana; Nicodemi, Mario

    2015-04-01

    Understanding the mechanisms that control the organization of chromosomes in the space of the nucleus of cells, and its contribution to gene regulation, is a key open issue in molecular biology. New technologies have shown that chromosomes have a complex 3D organization, which dynamically changes across organisms and cell types. To understand such complex behaviors, quantitative models from polymer physics have been developed, to find the principles of chromosome folding, their origin and function. Here, we provide a short review of recent progress in such an important research field where Physical and Life Sciences meet.

  7. Characterization of low dielectric constant plasma polymer films deposited by plasma-enhanced chemical vapor deposition using decamethyl-cyclopentasiloxane and cyclohexane as the precursors

    SciTech Connect

    Yang, Jaeyoung; Lee, Sungwoo; Park, Hyoungsun; Jung, Donggeun; Chae, Heeyeop

    2006-01-15

    We investigated the properties of plasma polymer films deposited by plasma-enhanced chemical vapor deposition using a mixture of decamethyl-cyclopentasiloxane (C{sub 10}H{sub 30}O{sub 5}Si{sub 5}) and cyclohexane (C{sub 6}H{sub 12}) as the precursors, which we refer to as plasma polymerized decamethyl-cyclopentasiloxane: cyclohexane (PPDMCPSO:CHex) films. The relative dielectric constants, k, of the plasma polymer films were correlated with the Fourier transform infrared absorption peaks of the C-Hx, Si-CH{sub 3}, and Si-O related groups. As the amount of the CHx species in the as-deposited plasma polymer films increased, the k value and the leakage current density of the thin films decreased. The subsequent annealing of the PPDMCPSO:CHex film at 400 deg. C for 1 h further reduced the k value to as low as k=2.05. This annealed PPDMCPSO:CHex thin film showed a leakage current density of the order of 4x10{sup -7} A/cm{sup 2} at 1 MV/cm and a breakdown field of 6.5 MV/cm. Through the bias-temperature stress test, it was estimated that the PPDMCPSO:CHex film with a k value of 2.05 would retain its insulating properties for ten years at 167 deg. C under an electrical field of 1 MV/cm, when it is presented as a layer adjacent to Cu/TaN(10 nm)

  8. Electrochromic conductive polymer fuses for hybrid organic/inorganic semiconductor memories

    NASA Astrophysics Data System (ADS)

    Möller, Sven; Forrest, Stephen R.; Perlov, Craig; Jackson, Warren; Taussig, Carl

    2003-12-01

    We demonstrate a nonvolatile, write-once-read-many-times (WORM) memory device employing a hybrid organic/inorganic semiconductor architecture consisting of thin film p-i-n silicon diode on a stainless steel substrate integrated in series with a conductive polymer fuse. The nonlinearity of the silicon diodes enables a passive matrix memory architecture, while the conductive polyethylenedioxythiophene:polystyrene sulfonic acid polymer serves as a reliable switch with fuse-like behavior for data storage. The polymer can be switched at ˜2 μs, resulting in a permanent decrease of conductivity of the memory pixel by up to a factor of 103. The switching mechanism is primarily due to a current and thermally dependent redox reaction in the polymer, limited by the double injection of both holes and electrons. The switched device performance does not degrade after many thousand read cycles in ambient at room temperature. Our results suggest that low cost, organic/inorganic WORM memories are feasible for light weight, high density, robust, and fast archival storage applications.

  9. Morphology control of phase separated ferroelectric-semiconductor polymer blends for organic memory

    NASA Astrophysics Data System (ADS)

    Su, Gregory; Jacobs, Andrew; Kramer, Edward; Chabinyc, Michael

    2014-03-01

    The ability to store memory is essential for many electronic applications. All-organic memory devices based on a blend of a ferroelectric polymer and a semiconducting polymer have recently shown great promise for low-cost memory technology based on ferroelectricity. The thin film morphology of the phase separated ferroelectric-semiconductor polymer blend is critically important for working devices and improved operation. However, precise morphology control has so far been relatively unattainable. Here, we report on a new semiconducting polythiophene with a modified side chain structure (PEPT) that demonstrates a greatly improved phase separated morphology with the well-studied ferroelectric polymer poly[(vinylidenefluoride-co-trifluoroethylene] (PVDF-TrFE). Thin film surface and bulk characterization via microscopy, soft X-ray spectroscopy, and X-ray scattering experiments reveal that PEPT:PVDF-TrFE blends exhibit domain sizes that are easily tunable through simple parameters such as blend ratio. These results demonstrate progress toward achieving organic ferroelectric-semiconductor memory with optimized morphology and the techniques required for thorough thin film surface and bulk characterization.

  10. Poling and characterization of a novel organic/polymer electro-optic material

    NASA Astrophysics Data System (ADS)

    Liao, Jinkun; Tang, Xianzhong; Lu, Rongguo; Tang, Xionggui; Li, Heping; Zhang, Xiaoxia; Liu, Yongzhi

    2010-10-01

    Electro-optic organic/polymer material is important for the fabrication of polymer integrated optic-electronic devices and organic sensors. Recently, a novel organic high μβ value chromophore FFC have been synthesized by molecular design. The absorption spectrum in 400-4000 cm-1 is measured for the material, and the measurement result shows that the absorption loss is negligibly small. An organic/polymer high electro-optic activity material FFC/PSU is obtained by dissolving guest FFC (wt. 20%) and a host polysulfone (PSU) in a solvent. The resolvability of cyclohexanone for the material is satisfactory by comparison with other solvents experimentally, and the preparation of FFC/PSU thin film is ease relatively. The materiel is poled by electric field-assisted contact poling, and the near optimum poling condition is determined by adjusting poling parameters as pre-curing duration, poling temperature and poling voltage etc. The electro-optic coefficient of the material is measured as high as 130pm/V by using the widely accepted simple reflection technique. The investigation indicates that the FFC/PSU has excellent characteristics, such as high electro-optic coefficient, low absorption loss, good thermal stability and capability for withstanding the subsequent process techniques, suitable for the fabrication of high-performance integrated optic-electronic devices and sensors.

  11. Improved performance of polymer solar cells by using inorganic, organic, and doped cathode buffer layers

    NASA Astrophysics Data System (ADS)

    Taohong, Wang; Changbo, Chen; Kunping, Guo; Guo, Chen; Tao, Xu; Bin, Wei

    2016-03-01

    The interface between the active layer and the electrode is one of the most critical factors that could affect the device performance of polymer solar cells. In this work, based on the typical poly(3-hexylthiophene):[6,6]-phenyl C61-butyric acid methyl ester (P3HT:PCBM) polymer solar cell, we studied the effect of the cathode buffer layer (CBL) between the top metal electrode and the active layer on the device performance. Several inorganic and organic materials commonly used as the electron injection layer in an organic light-emitting diode (OLED) were employed as the CBL in the P3HT:PCBM polymer solar cells. Our results demonstrate that the inorganic and organic materials like Cs2CO3, bathophenanthroline (Bphen), and 8-hydroxyquinolatolithium (Liq) can be used as CBL to efficiently improve the device performance of the P3HT:PCBM polymer solar cells. The P3HT:PCBM devices employed various CBLs possess power conversion efficiencies (PCEs) of 3.0%-3.3%, which are ca. 50% improved compared to that of the device without CBL. Furthermore, by using the doped organic materials Bphen:Cs2CO3 and Bphen:Liq as the CBL, the PCE of the P3HT:PCBM device will be further improved to 3.5%, which is ca. 70% higher than that of the device without a CBL and ca. 10% increased compared with that of the devices with a neat inorganic or organic CBL. Project supported by the National Natural Science Foundation of China (Grant No. 61204014), the “Chenguang” Project (13CG42) supported by Shanghai Municipal Education Commission and Shanghai Education Development Foundation, China, and the Shanghai University Young Teacher Training Program of Shanghai Municipality, China.

  12. Properties of poly(ethylene terephthalate) track membranes with a polymer layer obtained by plasma polymerization of pyrrole vapors

    NASA Astrophysics Data System (ADS)

    Kravets, L.; Dmitriev, S.; Lizunov, N.; Satulu, V.; Mitu, B.; Dinescu, G.

    2010-03-01

    The structure and the charge transport properties of poly(ethylene terephthalate) track membrane modified by pyrrole plasma were studied. It was found that polymer deposition on the surface of a track membrane via plasma polymerization of pyrrole results in the creation of composite nanomembranes that, in the case of the formation of a semipermeable layer, possess asymmetric conductivity in electrolyte solutions - a rectification effect similar to that of a p-n junction in semiconductors. It is caused by presence in the membranes of two layers with different functional groups and also by the pore geometry. Such membranes can be used to create chemical and biochemical sensors.

  13. Grafting of bovine serum albumin proteins on plasma-modified polymers for potential application in tissue engineering

    NASA Astrophysics Data System (ADS)

    Kasálková, Nikola Slepičková; Slepička, Petr; Kolská, Zdeňka; Hodačová, Petra; Kučková, Štěpánka; Švorčík, Václav

    2014-04-01

    In this work, an influence of bovine serum albumin proteins grafting on the surface properties of plasma-treated polyethylene and poly- l-lactic acid was studied. The interaction of the vascular smooth muscle cells with the modified polymer surface was determined. The surface properties were characterized by X-ray photoelectron spectroscopy, atomic force microscopy, nano-LC-ESI-Q-TOF mass spectrometry, electrokinetic analysis, and goniometry. One of the motivations for this work is the idea that by the interaction of the cell with substrate surface, the proteins will form an interlayer between the cell and the substrate. It was proven that when interacting with the plasma-treated high-density polyethylene and poly- l-lactic acid, the bovine serum albumin protein is grafted on the polymer surface. Since the proteins are bonded to the substrate surface, they can stimulate cell adhesion and proliferation.

  14. Grafting of bovine serum albumin proteins on plasma-modified polymers for potential application in tissue engineering

    PubMed Central

    2014-01-01

    In this work, an influence of bovine serum albumin proteins grafting on the surface properties of plasma-treated polyethylene and poly-l-lactic acid was studied. The interaction of the vascular smooth muscle cells with the modified polymer surface was determined. The surface properties were characterized by X-ray photoelectron spectroscopy, atomic force microscopy, nano-LC-ESI-Q-TOF mass spectrometry, electrokinetic analysis, and goniometry. One of the motivations for this work is the idea that by the interaction of the cell with substrate surface, the proteins will form an interlayer between the cell and the substrate. It was proven that when interacting with the plasma-treated high-density polyethylene and poly-l-lactic acid, the bovine serum albumin protein is grafted on the polymer surface. Since the proteins are bonded to the substrate surface, they can stimulate cell adhesion and proliferation. PMID:24708858

  15. Production of organic compounds in plasmas - A comparison among electric sparks, laser-induced plasmas, and UV light

    NASA Astrophysics Data System (ADS)

    Scattergood, T. W.; McKay, C. P.; Borucki, W. J.; Giver, L. P.; van Ghyseghem, H.; Parris, J. E.; Miller, S. L.

    1989-10-01

    In order to ascertain the features of organic compound-production in planetary atmospheres under the effects of plasmas and shocks, various mixtures of N2, CH4, and H2 modeling the atmosphere of Titan were subjected to discrete sparks, laser-induced plasmas, and UV radiation. The experimental results obtained suggest that UV photolysis from the plasma is an important organic compound synthesis process, as confirmed by the photolysis of gas samples that were exposed to the light but not to the shock waves emitted by the sparks. The thermodynamic equilibrium theory is therefore incomplete in the absence of photolysis.

  16. Production of organic compounds in plasmas - A comparison among electric sparks, laser-induced plasmas, and UV light

    NASA Technical Reports Server (NTRS)

    Scattergood, Thomas W.; Mckay, Christopher P.; Borucki, William J.; Giver, Lawrence P.; Van Ghyseghem, Hilde

    1989-01-01

    In order to ascertain the features of organic compound-production in planetary atmospheres under the effects of plasmas and shocks, various mixtures of N2, CH4, and H2 modeling the atmosphere of Titan were subjected to discrete sparks, laser-induced plasmas, and UV radiation. The experimental results obtained suggest that UV photolysis from the plasma is an important organic compound synthesis process, as confirmed by the photolysis of gas samples that were exposed to the light but not to the shock waves emitted by the sparks. The thermodynamic equilibrium theory is therefore incomplete in the absence of photolysis.

  17. Incineration of radioactive organic liquid wastes by underwater thermal plasma

    NASA Astrophysics Data System (ADS)

    Mabrouk, M.; Lemont, F.; Baronnet, J. M.

    2012-12-01

    This work deals with incineration of radioactive organic liquid wastes using an oxygen thermal plasma jet, submerged under water. The results presented here are focused on incineration of three different wastes: a mixture of tributylphosphate (TBP) and dodecane, a perfluoropolyether oil (PFPE) and trichloroethylene (TCE). To evaluate the plutonium behavior in used TBP/dodecane incineration, zirconium is used as a surrogate of plutonium; the method to enrich TBP/dodecane mixture in zirconium is detailed. Experimental set-up is described. During a trial run, CO2 and CO contents in the exhaust gas are continuously measured; samples, periodically taken from the solution, are analyzed by appropriate chemical methods: contents in total organic carbon (COT), phosphorus, fluoride and nitrates are measured. Condensed residues are characterized by RX diffraction and SEM with EDS. Process efficiency, during tests with a few L/h of separated or mixed wastes, is given by mineralization rate which is better than 99.9 % for feed rate up to 4 L/h. Trapping rate is also better than 99 % for phosphorous as for fluorine and chlorine. Those trials, with long duration, have shown that there is no corrosion problems, also the hydrogen chloride and fluoride have been neutralized by an aqueous solution of potassium carbonate.

  18. Surface plasma modification and tropoelastin coating of a polyurethane co-polymer for enhanced cell attachment and reduced thrombogenicity.

    PubMed

    Bax, Daniel V; Kondyurin, Alexey; Waterhouse, Anna; McKenzie, David R; Weiss, Anthony S; Bilek, Marcela M M

    2014-08-01

    Polymers currently utilized for dermal and vascular applications possess sub-optimal biocompatibility which reduces their efficacy. Improving the cell-binding and blood-contacting properties of these polymers would substantially improve their clinical utility. Tropoelastin is a highly extensible extracellular matrix protein with beneficial cell interactive and low thrombogenic properties. We transferred these benefits to the polyurethane block copolymer Elast-Eon E2A through a specific combination of surface plasma modifications and coating with human tropoelastin. The cell-binding activity of bound tropoelastin was modulated by ion implantation of the underlying polymer, and correlated with surface hydrophobicity, carbon and oxygen content. This combined treatment enhanced human dermal fibroblast (HDF) and human umbilical vein endothelial cell (HUVEC) attachment, cytoskeletal assembly and viability, combined with elevated PECAM-1 staining of HUVEC cell junctions. The thrombogenicity of the polymer was ameliorated by tropoelastin coating. We propose that a combination of metered plasma treatment and tropoelastin coating of Elast-Eon can serve to improve the biological performance of implantable devices such as vascular conduits.

  19. Mechanism of plasma-induced damage to low-k SiOCH films during plasma ashing of organic resists

    NASA Astrophysics Data System (ADS)

    Takeda, Keigo; Miyawaki, Yudai; Takashima, Seigo; Fukasawa, Masanaga; Oshima, Keiji; Nagahata, Kazunori; Tatsumi, Tetsuya; Hori, Masaru

    2011-02-01

    Plasma-induced damage to porous SiOCH (p-SiOCH) films during organic resist film ashing using dual-frequency capacitively coupled O2 plasmas was investigated using the pallet for plasma evaluation method developed by our group. The damage was characterized by ellipsometry and Fourier-transform infrared spectroscopy. Individual and synergetic damage associated with vacuum ultraviolet (VUV) and UV radiation, radicals, and ions in the O2 plasma were clarified. It was found that the damage was caused not only by radicals but also by synergetic reactions of radicals with VUV and UV radiation emitted by the plasmas. It is noteworthy that the damage induced by plasma exposure without ion bombardment was larger than the damage with ion bombardment. These results differed from those obtained using an H2/N2 plasma for resist ashing. Finally, the mechanism of damage to p-SiOCH caused by O2 and H2/N2 plasma ashing of organic resist films is discussed. These results are very important in understanding the mechanism of plasma-induced damage to p-SiOCH films.

  20. Mechanism of plasma-induced damage to low-k SiOCH films during plasma ashing of organic resists

    SciTech Connect

    Takeda, Keigo; Miyawaki, Yudai; Takashima, Seigo; Fukasawa, Masanaga; Oshima, Keiji; Nagahata, Kazunori; Tatsumi, Tetsuya; Hori, Masaru

    2011-02-01

    Plasma-induced damage to porous SiOCH (p-SiOCH) films during organic resist film ashing using dual-frequency capacitively coupled O{sub 2} plasmas was investigated using the pallet for plasma evaluation method developed by our group. The damage was characterized by ellipsometry and Fourier-transform infrared spectroscopy. Individual and synergetic damage associated with vacuum ultraviolet (VUV) and UV radiation, radicals, and ions in the O{sub 2} plasma were clarified. It was found that the damage was caused not only by radicals but also by synergetic reactions of radicals with VUV and UV radiation emitted by the plasmas. It is noteworthy that the damage induced by plasma exposure without ion bombardment was larger than the damage with ion bombardment. These results differed from those obtained using an H{sub 2}/N{sub 2} plasma for resist ashing. Finally, the mechanism of damage to p-SiOCH caused by O{sub 2} and H{sub 2}/N{sub 2} plasma ashing of organic resist films is discussed. These results are very important in understanding the mechanism of plasma-induced damage to p-SiOCH films.

  1. Bio-Organic Nanotechnology: Using Proteins and Synthetic Polymers for Nanoscale Devices

    NASA Technical Reports Server (NTRS)

    Molnar, Linda K.; Xu, Ting; Trent, Jonathan D.; Russell, Thomas P.

    2003-01-01

    While the ability of proteins to self-assemble makes them powerful tools in nanotechnology, in biological systems protein-based structures ultimately depend on the context in which they form. We combine the self-assembling properties of synthetic diblock copolymers and proteins to construct intricately ordered, three-dimensional polymer protein structures with the ultimate goal of forming nano-scale devices. This hybrid approach takes advantage of the capabilities of organic polymer chemistry to build ordered structures and the capabilities of genetic engineering to create proteins that are selective for inorganic or organic substrates. Here, microphase-separated block copolymers coupled with genetically engineered heat shock proteins are used to produce nano-scale patterning that maximizes the potential for both increased structural complexity and integrity.

  2. BPTs: thiophene-flanked benzodipyrrolidone conjugated polymers for ambipolar organic transistors.

    PubMed

    Rumer, Joseph W; Levick, Matthew; Dai, Sheng-Yao; Rossbauer, Stephan; Huang, Zhenggang; Biniek, Laure; Anthopoulos, Thomas D; Durrant, James R; Procter, David J; McCulloch, Iain

    2013-05-18

    A series of novel thiophene-flanked benzodipyrrolidone (BPT)-based alternating copolymers are synthesised, their optical and electrical properties evaluated. The BPT unit promotes a conjugated, planar polymer backbone, with a low bandgap, primarily due to low lying LUMO energy levels. Copolymerisation with thiophene exhibits well balanced ambipolar organic field-effect transistor performance, with electron and hole mobilities 0.1 and 0.2 cm(2) V(-1) s(-1), respectively.

  3. Fluorinated microporous organic polymers: design and applications in CO₂ adsorption and conversion.

    PubMed

    Yang, Zhen-Zhen; Zhao, Yanfei; Zhang, Hongye; Yu, Bo; Ma, Zhishuang; Ji, Guipeng; Liu, Zhimin

    2014-11-21

    Fluorinated microporous organic polymers (F-MOPs) were designed, showing twice higher CO2 adsorption capacity than corresponding non-fluorous MOPs. The incorporation of phenanthroline moieties into F-MOPs afforded them the ability to coordinate with Ag(I), and the resultant F-MOP-Ag(I) displayed high efficiency for the reaction of CO2 with propargyl alcohols to form α-alkylidene cyclic carbonates at 25 °C.

  4. A new benzimidazole based covalent organic polymer having high energy storage capacity.

    PubMed

    Patra, Bidhan C; Khilari, Santimoy; Satyanarayana, Lanka; Pradhan, Debabrata; Bhaumik, Asim

    2016-06-18

    We report the synthesis of a new benzimidazole-based covalent organic polymer (TpDAB) via solvothermal Schiff base condensation between 1,3,5-triformylphloroglucinol (Tp) and 3,3'-diaminobenzidine (DAB). TpDAB showed high energy storage capacity with a specific capacitance of 335 F g(-1) at 2 mV s(-1) scan rate and good cyclic stability with 93% retention of its initial specific capacitance after 1000 cycles. PMID:27222226

  5. In situ formation of well-dispersed palladium nanoparticles immobilized in imidazolium-based organic ionic polymers.

    PubMed

    Zhao, Huaixia; Wang, Yangxin; Wang, Ruihu

    2014-09-25

    A new strategy for in situ generation of well-dispersed palladium nanoparticles (NPs) immobilized in imidazolium-based organic ionic polymers was presented. Without extra addition of palladium species, the as-synthesized ionic polymers showed excellent catalytic activity and good reusability in the hydrogenation of nitroarenes.

  6. Organic/Organic Cathode Bi-Interlayers Based on a Water-Soluble Nonconjugated Polymer and an Alcohol-Soluble Conjugated Polymer for High Efficiency Inverted Polymer Solar Cells.

    PubMed

    Cai, Ping; Jia, Hongfu; Chen, Junwu; Cao, Yong

    2015-12-23

    In this work, organic/organic cathode bi-interlayers based on a water-soluble nonconjugated polymer PDMC and an alcohol-soluble conjugated polymer PFN were introduced to modifythe ITO cathode for inverted polymer solar cells (PSCs). PDMC with ultrahigh molecular weight would facilitate to form strong adsorption on the ITO substrate, while PFN could provide both compatibly interfacial contacts with the bottom PDMC interlayer and the upper organic active layer. The PDMC/PFN cathode bi-interlayers could decrease work function of the ITO cathode to 3.8 eV, supplying the most efficient ohmic interfacial contacts for electron collection at the ITO cathode. With a PTB7:PC71BM blend as the active layer, inverted PSCs based on the PDMC/PFN cathode bi-interlayers showed the highest efficiency of 9.01% and the best air stability within 60 days if compared with devices based on a separate PDMC or PFN cathode interlayer. The results suggest that the PDMC/PFN cathode bi-interlayers would play an important role to achieve high efficiency and stable inverted PSCs.

  7. Self-healing antimicrobial polymer coating with efficacy in the presence of organic matter

    NASA Astrophysics Data System (ADS)

    Bastarrachea, Luis J.; Goddard, Julie M.

    2016-08-01

    A method to prepare a self-healing, antimicrobial polymer coating that retains efficacy against Escherichia coli O157:H7 in the presence of organic matter is reported. A coating composed of branched polyethyleneimine (PEI) and styrene maleic anhydride copolymer (SMA) was applied to a maleic anhydride functionalized polypropylene support. The chemistry of the polymer coating was designed to impart hydrophobicity due to the styrene subunits, intrinsic antimicrobial character (>99.9% reduction) from the cationic primary amine groups, and enhanced antimicrobial character (> 99.99% reduction) after chlorination of N-halamine forming groups. Antimicrobial effectiveness was demonstrated under conditions of increasing organic load. Up to 500 ppm horse serum, chlorinated coatings retained full antimicrobial character (>99.99% reduction). Even at 50,000 ppm of horse serum, the coating provided ∼90% reduction as prepared, and between ∼75% and ∼80% reduction in the form of N-halamines. Microscopy confirmed no evidence of bacterial adhesion on the coating surface. Finally, the coating exhibited self-healing properties after exposure to acid and alkaline solutions and restoration by heat, as confirmed through spectroscopy from the rebuilding of characteristic chemical bonds. Such robust antimicrobial polymer coatings with efficacy under conditions of increasing organic load may support reducing microbial cross-contamination in food and biomedical industries.

  8. Highly stable organic polymer field-effect transistor sensor for selective detection in the marine environment.

    PubMed

    Knopfmacher, Oren; Hammock, Mallory L; Appleton, Anthony L; Schwartz, Gregor; Mei, Jianguo; Lei, Ting; Pei, Jian; Bao, Zhenan

    2014-01-01

    In recent decades, the susceptibility to degradation in both ambient and aqueous environments has prevented organic electronics from gaining rapid traction for sensing applications. Here we report an organic field-effect transistor sensor that overcomes this barrier using a solution-processable isoindigo-based polymer semiconductor. More importantly, these organic field-effect transistor sensors are stable in both freshwater and seawater environments over extended periods of time. The organic field-effect transistor sensors are further capable of selectively sensing heavy-metal ions in seawater. This discovery has potential for inexpensive, ink-jet printed, and large-scale environmental monitoring devices that can be deployed in areas once thought of as beyond the scope of organic materials.

  9. Highly stable organic polymer field-effect transistor sensor for selective detection in the marine environment.

    PubMed

    Knopfmacher, Oren; Hammock, Mallory L; Appleton, Anthony L; Schwartz, Gregor; Mei, Jianguo; Lei, Ting; Pei, Jian; Bao, Zhenan

    2014-01-01

    In recent decades, the susceptibility to degradation in both ambient and aqueous environments has prevented organic electronics from gaining rapid traction for sensing applications. Here we report an organic field-effect transistor sensor that overcomes this barrier using a solution-processable isoindigo-based polymer semiconductor. More importantly, these organic field-effect transistor sensors are stable in both freshwater and seawater environments over extended periods of time. The organic field-effect transistor sensors are further capable of selectively sensing heavy-metal ions in seawater. This discovery has potential for inexpensive, ink-jet printed, and large-scale environmental monitoring devices that can be deployed in areas once thought of as beyond the scope of organic materials. PMID:24389531

  10. Surface modification of a ferroelectric polymer insulator for low-voltage readable nonvolatile memory in an organic field-effect transistor

    NASA Astrophysics Data System (ADS)

    Kim, Won-Ho; Bae, Jin-Hyuk; Kim, Min-Hoi; Keum, Chang-Min; Park, Jaehoon; Lee, Sin-Doo

    2011-01-01

    We demonstrate that the sequential surface modification of a ferroelectric polymer insulator plays an essential role in both the enhancement of the carrier mobility and the shift in the turn-on voltage (Von) in an organic ferroelectric field-effect transistor (FeFET) for nonvolatile memory. The surface of a ferroelectric polymer insulator, poly(vinylidene fluoride-trifluoroethylene), is physicochemically modified by the successive treatments of ultraviolet-ozone (UVO) and CF4 plasma to understand how the surface morphology and the hydrophobicity affect the grain size, the mobility, and Von in the FeFET. In a pentacene-based FeFET, the CF4 plasma irradiation leads to the mobility enhancement by a factor of about 5 as well as the shift in Von toward a positive voltage direction while the UVO treatment results in only the shift in Von toward a negative voltage direction. It is found that the sequence of the two successive treatments is critical for tailoring interfacial interactions between the ferroelectric polymer insulator and the pentacene layer. The underlying mechanism for the mobility enhancement and the shift in Von is described in terms of the surface morphology and the nature of the built-in electric field.

  11. Synthesis and characterization of organic semiconducting polymers containing dithienylfluorenone for use in organic photovoltaic cells.

    PubMed

    Byun, Yun-Sun; Kim, Ji-Hoon; Park, Jong Baek; Hwang, Do-Hoon

    2014-08-01

    2,7-Bis(5-bromo-4-hexylthiophen-2-yl)-9H-fluoren-9-one (DTFO) was synthesized as a new electron-accepting material in semiconducting polymers for use in photovoltaic devices. The synthesized DTFO was polymerized with two different electron-donating counter monomers: 2,7-dibromo-9,9-dioctyl-9H-fluorene (DOF) and 2,6-bis(trimethyltin)-4,8-di(2-ethylhexyloxyl)benzo [1,2-b:4,5-b']dithiophene (BDT). Two alternating copolymers, poly(DTFO-alt-DOF) and poly(DTFO-alt-BDT), were synthesized through the Suzuki and Stille coupling polymerizations, respectively. The synthesized polymers exhibited good solubility in common solvents and show good thermal stability up to 350 °C. The optical band gap energies of poly(DTFO-alt-DOF) and poly(DTFO-alt-BDT) were determined to be 2.44 and 2.23 eV, respectively. The positions of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the polymers were determined by cyclic voltammetry (CV). One of these devices showed a power conversion efficiency of 0.50%, with an open-circuit voltage of 0.67 V, a short-circuit current of 2.34 mA/cm2, and a fill factor of 0.30 under air mass (AM) 1.5 global (1.5 G) illumination conditions (100 mW/cm2).

  12. Hierarchies in eukaryotic genome organization: Insights from polymer theory and simulations

    PubMed Central

    2011-01-01

    Eukaryotic genomes possess an elaborate and dynamic higher-order structure within the limiting confines of the cell nucleus. Knowledge of the physical principles and the molecular machinery that govern the 3D organization of this structure and its regulation are key to understanding the relationship between genome structure and function. Elegant microscopy and chromosome conformation capture techniques supported by analysis based on polymer models are important steps in this direction. Here, we review results from these efforts and provide some additional insights that elucidate the relationship between structure and function at different hierarchical levels of genome organization. PMID:21595865

  13. Efficient Organic Photovoltaics Utilizing Nanoscale Heterojunctions in Sequentially Deposited Polymer/fullerene Bilayer

    NASA Astrophysics Data System (ADS)

    Seok, Jeesoo; Shin, Tae Joo; Park, Sungmin; Cho, Changsoon; Lee, Jung-Yong; Yeol Ryu, Du; Kim, Myung Hwa; Kim, Kyungkon

    2015-02-01

    A highly efficient sequentially deposited bilayer (SD-bilayer) of polymer/fullerene organic photovoltaic (OPV) device is developed via the solution process. Herein, we resolve two essential problems regarding the construction of an efficient SD-bilayer OPV. First, the solution process fabrication of the SD-bilayer is resolved by incorporating an ordering agent (OA) to the polymer solution, which improves the ordering of the polymer chain and prevents the bottom-layer from dissolving into the top-layer solution. Second, a non-planar heterojunction with a large surface area is formed by the incorporation of a heterojunction agent (HA) to the top-layer solution. Poly[[9-(1-octylnonyl)-9H-carbazole-2,7-diyl]-2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl] (PCDTBT) is used for the bottom-layer and phenyl-C71-butyric-acid-methyl ester (PC70BM) is used for the top-layer. The SD-bilayer OPV produced utilizing both an OA and HA exhibits a power conversion efficiency (PCE) of 7.12% with a high internal quantum efficiency (IQE). We believe our bilayer system affords a new way of forming OPVs distinct from bulk heterojunction (BHJ) systems and offers a chance to reconsider the polymers that have thus far shown unsatisfactory performance in BHJ systems.

  14. Efficient organic photovoltaics utilizing nanoscale heterojunctions in sequentially deposited polymer/fullerene bilayer.

    PubMed

    Seok, Jeesoo; Shin, Tae Joo; Park, Sungmin; Cho, Changsoon; Lee, Jung-Yong; Yeol Ryu, Du; Kim, Myung Hwa; Kim, Kyungkon

    2015-02-11

    A highly efficient sequentially deposited bilayer (SD-bilayer) of polymer/fullerene organic photovoltaic (OPV) device is developed via the solution process. Herein, we resolve two essential problems regarding the construction of an efficient SD-bilayer OPV. First, the solution process fabrication of the SD-bilayer is resolved by incorporating an ordering agent (OA) to the polymer solution, which improves the ordering of the polymer chain and prevents the bottom-layer from dissolving into the top-layer solution. Second, a non-planar heterojunction with a large surface area is formed by the incorporation of a heterojunction agent (HA) to the top-layer solution. Poly[[9-(1-octylnonyl)-9H-carbazole-2,7-diyl]-2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl] (PCDTBT) is used for the bottom-layer and phenyl-C71-butyric-acid-methyl ester (PC70BM) is used for the top-layer. The SD-bilayer OPV produced utilizing both an OA and HA exhibits a power conversion efficiency (PCE) of 7.12% with a high internal quantum efficiency (IQE). We believe our bilayer system affords a new way of forming OPVs distinct from bulk heterojunction (BHJ) systems and offers a chance to reconsider the polymers that have thus far shown unsatisfactory performance in BHJ systems.

  15. Surface binding of polymer coated nanoparticles: Coupling of physical interactions, molecular organization, and chemical state

    NASA Astrophysics Data System (ADS)

    Nap, Rikkert; Szleifer, Igal

    2014-03-01

    A key challenge in nanomedicine is to design carrier system for drug delivery that selectively binds to target cells without binding to healthy cells. A common strategy is to end-functionalize the polymers coating of the delivery device with specific ligands that bind strongly to overexpressed receptors. Such devices are usually unable to discriminate between receptors found on benign and malignant cells. We demonstrate, theoretically, how one can achieve selective binding to target cells by using multiple physical and chemical interactions. We study the effective interactions between a polymer decorated nanosized micelle or solid nanoparticle with model lipid layers. The polymer coating contains a mixture of two polymers, one neutral for protection and the other a polybase with a functional end-group to optimize specific binding and electrostatic interactions with the charged lipid head-groups found on the lipid surface. The strength of the binding for the combined system is much larger than the sum of the independent electrostatic or specific ligand-receptor binding. The search for optimal binding conditions lead to the finding of a non-additive coupling that exists in systems where chemical equilibrium, molecular organization, and physical interactions are coupled together.

  16. Polymer Brush Surfaces Showing Superhydrophobicity and Air-Bubble Repellency in a Variety of Organic Liquids.

    PubMed

    Dunderdale, Gary J; England, Matt W; Urata, Chihiro; Hozumi, Atsushi

    2015-06-10

    Silicon (Si) substrates were modified with polyalkyl methacrylate brushes having different alkyl chain lengths (C(n), where n = 1, 4, 8, and 18) using ARGET-ATRP at ambient temperature without purging the reaction solution of oxygen. The dynamic hydrophobicity of these polymer brush-covered Si surfaces when submerged in a variety of organic solvents (1-butanol, dichloromethane, toluene, n-hexane) depended markedly on the alkyl chain length and to a lesser extent polymer solubility. Long-chain poly(stearyl methacrylate) brushes (C(n) = 18) submerged in toluene showed excellent water-repellant properties, having large advancing/receding contact angles (CAs) of 169°/168° with negligible CA hysteresis (1°). Whereas polymer brushes with short alkyl-chain (C(n) ≤ 4) had significantly worse water drop mobility because of small CAs (as low as 125°/55°) and large CA hysteresis (up to 70°). However, such poor dynamic dewetting behavior of these surfaces was found to significantly improve when water drops impacted onto the surfaces at moderate velocities. Under these conditions, all brush surfaces were able to expel water drops from their surface. In addition, our brush surfaces were also highly repellant toward air bubbles under all conditions, irrespective of C(n) or polymer solubility. These excellent surface properties were found to be vastly superior to the performance of conventional perfluoroalkylsilane-derived surfaces. PMID:25988214

  17. Efficient organic photovoltaics utilizing nanoscale heterojunctions in sequentially deposited polymer/fullerene bilayer.

    PubMed

    Seok, Jeesoo; Shin, Tae Joo; Park, Sungmin; Cho, Changsoon; Lee, Jung-Yong; Yeol Ryu, Du; Kim, Myung Hwa; Kim, Kyungkon

    2015-01-01

    A highly efficient sequentially deposited bilayer (SD-bilayer) of polymer/fullerene organic photovoltaic (OPV) device is developed via the solution process. Herein, we resolve two essential problems regarding the construction of an efficient SD-bilayer OPV. First, the solution process fabrication of the SD-bilayer is resolved by incorporating an ordering agent (OA) to the polymer solution, which improves the ordering of the polymer chain and prevents the bottom-layer from dissolving into the top-layer solution. Second, a non-planar heterojunction with a large surface area is formed by the incorporation of a heterojunction agent (HA) to the top-layer solution. Poly[[9-(1-octylnonyl)-9H-carbazole-2,7-diyl]-2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl] (PCDTBT) is used for the bottom-layer and phenyl-C71-butyric-acid-methyl ester (PC70BM) is used for the top-layer. The SD-bilayer OPV produced utilizing both an OA and HA exhibits a power conversion efficiency (PCE) of 7.12% with a high internal quantum efficiency (IQE). We believe our bilayer system affords a new way of forming OPVs distinct from bulk heterojunction (BHJ) systems and offers a chance to reconsider the polymers that have thus far shown unsatisfactory performance in BHJ systems. PMID:25670623

  18. The Influence of Polymer Sequence on the Formation of Bulk-Heterojunctions in Organic Solar Cells

    NASA Astrophysics Data System (ADS)

    Gao, Dong

    This thesis summarizes my work on organic solar cells during my graduate studies. Chapter 1 serves as an introduction to organic solar cells. I will briefly discuss the working mechanism, and describe the device fabrication processes and testing set up that I designed at the beginning of my graduate studies. Chapter 2 describes the size-dependent behavior of polymer solar cells measured under partial illumination. We found that ITO resistance is a significant source of power loss because sheet resistance (Rs) increases with area. The non-illuminated part of a partially illuminated device introduces some interesting effects related to the physics of device operation. Specifically, this contributes additional "dark diodes" that connect in parallel with an illuminated cell, giving rise to an apparent decrease in VOC and increase in FF as the illuminated portion of the cell is decreased. Chapter 3 is a study of a P3HS-b-P3HT block copolymer as a donor material in organic solar cells. Fiber-like nanostructures are formed spontaneously in P3HS-b-P3HT:PCBM devices, and their thermal stability exceeds homopolymer:PCBM devices or ternary mixtures. Although P3HS-b-P3HT contains two distinct electron donor materials, the EQE spectra, hole mobility, Jsc, and PCE exceed that of a physical mixture of the two homopolymers and PCBM. Chapter 4 compares the photovoltaic properties of two conjugated copolymers with the same composition, P3HS-b-P3HT and P3HS- s-P3HT. The block polymer spontaneously undergoes intrinsic phase separation and the statistical polymer does not. P3HS-b-P3HT devices perform best when the native self-assembled structure is most perturbed, which is accomplished using PC71BM. P3HS-s-P3HT is a polymer that does not form a native phase separated structure. Here vapor annealing can be used to more predictably optimize the polymer:fullerene morphology. Chapter 5 studies the evolution of the electron mobility of two different acceptors with different crystallinity

  19. Plasma cell neoplasms in US solid organ transplant recipients.

    PubMed

    Engels, Eric A; Clarke, Christina A; Pfeiffer, Ruth M; Lynch, Charles F; Weisenburger, Dennis D; Gibson, Todd M; Landgren, Ola; Morton, Lindsay M

    2013-06-01

    Transplant recipients have elevated risk for plasma cell neoplasms (PCNs, comprising multiple myeloma and plasmacytoma), but little is known about risk factors in the transplant setting. Through linkage of the US solid organ transplant registry with 15 state/regional cancer registries, we identified 140 PCNs in 202 600 recipients (1987-2009). PCN risk was 1.8-fold increased relative to the general population (standardized incidence ratio [SIR] 1.80, 95%CI 1.51-2.12). Among cases, 102 were multiple myeloma (SIR 1.41) and 38 were plasmacytoma (SIR 7.06). PCN incidence increased with age, but due to the rarity of PCNs in younger people in the general population, SIRs were highest in younger transplant recipients (p = 0.03). PCN risk was especially high in recipients who were Epstein-Barr virus (EBV) seronegative at transplantation (SIR 3.93). EBV status was known for 18 tumors, of which 7 (39%) were EBV positive. Following liver transplantation, PCN risk was higher in recipients with cholestatic liver disease (SIR 2.78); five of these cases had primary biliary cirrhosis (PBC). A role for primary EBV infection after transplantation is supported by the increased PCN risk in young EBV seronegative recipients and the presence of EBV in tumors. PBC may be another risk factor, perhaps by causing chronic immune activation. PMID:23635036

  20. Molecular dynamics simulation study on substrate temperature dependence of sputtering yields for an organic polymer under ion bombardment

    SciTech Connect

    Yamashiro, Masashi; Yamada, Hideaki; Hamaguchi, Satoshi

    2007-02-15

    Substrate temperature dependence of sputtering yields in organic polymer etching processes has been examined with the use of molecular dynamics (MD) simulations. The simulation results indicate that structural weakness arising from high substrate temperatures alone is not sufficient to account for the experimentally observed strong dependence of sputtering yields on substrate temperatures. In other words, thermal desorption is likely to increase significantly at high substrate temperatures in reactive ion etching processes of organic polymers.

  1. Facile synthesis of one-dimensional organometallic-organic hybrid polymers based on a diphosphorus complex and flexible bipyridyl linkers.

    PubMed

    Elsayed Moussa, M; Attenberger, B; Peresypkina, E V; Fleischmann, M; Balázs, G; Scheer, M

    2016-08-21

    The selective synthesis of a series of new "ladderlike" one-dimensional organometallic-organic hybrid polymers is shown. The polymers are obtained from the reaction of the diphosphorus ligand complex [Cp2Mo2(CO)4(η(2)-P2)] with the copper salt [Cu(CH3CN)4]BF4 in the presence of flexible organic bipyridyl linkers in high selectivity. This unique behaviour is supported by DFT calculations.

  2. Conjugated Polymer-Small Molecule Alloy Leads to High Efficient Ternary Organic Solar Cells.

    PubMed

    Zhang, Jianqi; Zhang, Yajie; Fang, Jin; Lu, Kun; Wang, Zaiyu; Ma, Wei; Wei, Zhixiang

    2015-07-01

    Ternary organic solar cells are promising candidates for bulk heterojunction solar cells; however, improving the power conversion efficiency (PCE) is quite challenging because the ternary system is complicated on phase separation behavior. In this study, a ternary organic solar cell (OSC) with two donors, including one polymer (PTB7-Th), one small molecule (p-DTS(FBTTH2)2), and one acceptor (PC71BM), is fabricated. We propose the two donors in the ternary blend forms an alloy. A notable averaged PCE of 10.5% for ternary OSC is obtained due to the improvement of the fill factor (FF) and the short-circuit current density (J(sc)), and the open-circuit voltage (V(oc)) does not pin to the smaller V(oc) of the corresponding binary blends. A highly ordered face-on orientation of polymer molecules is obtained due to the formation of an alloy structure, which facilitates the enhancement of charge separation and transport and the reduction of charge recombination. This work indicates that a high crystallinity and the face-on orientation of polymers could be obtained by forming alloy with two miscible donors, thus paving a way to largely enhance the PCE of OSCs by using the ternary blend strategy.

  3. Electrochemically Directed Self-Assembly and Conjugated Polymer Semiconductors for Organic Electronic Applications

    NASA Astrophysics Data System (ADS)

    Pillai, Rajesh Gopalakrishna

    2011-07-01

    The research work presented in this thesis investigates the mechanistic details of conventional as well as electrochemically directed self-assembly of alkylthiosulfates and explores the use of conjugated semiconducting polymers for organic electronic applications. Here, the significance of the use of conjugated polymers is twofold; first, to explore their applications in nanoelectronics and second, the possibility of using them as a top contact on the self-assembled monolayers (SAMs) for molecular electronic applications. Throughout this work, deposition of the organic materials was performed on prefabricated device structures that required no further lithographic or metal deposition steps after modification of the electrodes with the organic molecules. Self-assembly of alkylthiosulfates on gold are reported to form monolayers identical to those formed from the corresponding alkanethiols. However, these self-assembly processes follow more complex mechanisms of monolayer formation than originally recognized. Studies on the mechanism of alkylthiosulfate chemisorption on gold shows that the self-assembly process is influenced by electrolyte and solvent. Plausible mechanisms have been proposed for the role of trace water in the solvent on conventional as well as electrochemically assisted self-assembly of alkylthiosulfates on gold. Electroanalytical and spectroscopic techniques have been used to explore the mechanistic details of electrochemically directed self-assembly of alkylthiosulfates on gold. It has been found that the self-assembly process is dynamic under electrochemical conditions and the heterogeneous electron transfer process between the organosulfur compound and gold is mediated through gold surface oxide and accompanied by corrosion. Conducting polymers are serious candidates for organic electronic applications since their properties can be controlled by the manipulation of molecular architecture. Unique electronic properties of conjugated polypyrrole

  4. Feasibility of atomic layer etching of polymer material based on sequential O{sub 2} exposure and Ar low-pressure plasma-etching

    SciTech Connect

    Vogli, Evelina; Metzler, Dominik; Oehrlein, Gottlieb S.

    2013-06-24

    We describe controlled, self-limited etching of a polystyrene polymer using a composite etching cycle consisting of sequential deposition of a thin reactive layer from precursors produced from a polymer-coated electrode within the etching chamber, modification using O{sub 2} exposure, and subsequent low-pressure Ar plasma etching, which removes the oxygen-modified deposited reactive layer along with Almost-Equal-To 0.1 nm unmodified polymer. Deposition prevents net etching of the unmodified polymer during the etching step and enables self-limited etch rates of 0.1 nm/cycle.

  5. Ultrasonic removal of organic deposits and polymer-induced formation damage

    SciTech Connect

    Roberts, P.M.; Venkitaraman, A.; Sharma, M.M.

    2000-03-01

    Experiments were conducted to investigate ultrasonic energy for reducing near-wellbore formation damage caused by organic deposits and polymers. It is shown that mechanical agitation provided by the acoustic waves re-suspends the paraffin and restores the effective permeability of the core to its undamaged condition. The depth of treatment is approximately 12 to 15 cm. This suggests that an acoustic source with or without solvents may provide an effective method of removing paraffins from the wellbore and the near-wellbore region. Ultrasonics was not as effective at restoring permeability damage caused by polymers. Results demonstrate that ultrasonic cleaning may be a viable method for cleaning the near-wellbore region when paraffin precipitation is a problem. The method would be particularly effective at treating long sections of pay where chemical methods may be too expensive.

  6. Analysis of physical mechanical and structural characteristics of microwave cured organic polymer parts

    NASA Astrophysics Data System (ADS)

    Guzeva, Tatiana; Zavitaeva, Yuliya; Chutskova, Evgeniya

    2015-02-01

    This paper presents experimental research which has confirmed the benefits of the new technology of curing polymer matrix for both laboratory and full-scale components, and compares with polymerization in an electrical-heated oven. Strength tests of small size specimens made of organic polymer determined that after microwave heating samples are capable of withstanding 1.3 greater loads than after heating in an electric furnace. Flexural modulus of full-scale specimens of organo-plastic, which were cured in a microwave radiation field showed greater modulus than samples which were polymerized in an electrical-heated oven at 40% and 20% respectively. The microstructure of the samples treated in the electric furnace were found to be porous, inhomogeneous, binding in large portions mixed up with pores spotted, accumulates on the edges and a separate central zones. Polymerization in microwave oven however, gave a microstructure which is more uniform and the binder distributed throughout the volume.

  7. Insertion of interlayers in efficient polymer-based organic solar cells for control of phase separation

    NASA Astrophysics Data System (ADS)

    Taima, Tetsuya; Tanaka, Jun; Kuwabara, Takayuki; Takahashi, Kohshin

    2016-02-01

    To improve the solar cell performance of polymer-based organic solar cells, the control of phase separation in the bulk heterojunction (BHJ) layer is important. In the case of a thienothiophene-benzodithiophene-based polymer (PTB7)-based solar cell, 1,8-diiodoctane (DIO) is added into the chlorobenzene solvent. However, it is well known that DIO addition causes degradation in long-term operation. Here, we try to improve the performance of the PTB7-based BHJ solar cell by controlling the phase separation in the BHJ layer through the insertion of an inorganic semiconducting copper iodide (CuI) interlayer between the BHJ layer and indium tin oxide. The power conversion efficiency of the PTB7-based solar cell is improved from 3.5 to 3.9% upon inserting the CuI interlayer without DIO addition.

  8. New N-Type Polymers for Organic Photovoltaics: Cooperative Research and Development Final Report, CRADA Number CRD-06-177

    SciTech Connect

    Olson, D.

    2014-08-01

    This CRADA will develop improved thin film organic solar cells using a new n-type semiconducting polymer. High efficiency photovoltaics (PVs) based on inorganic semiconductors have good efficiencies (up to 30%) but are extremely expensive to manufacture. Organic PV technology has the potential to overcome this problem through the use of high-throughput production methods like reel-to-reel printing on flexible substrates. Unfortunately, today's best organic PVs have only a few percent efficiency, a number that is insufficient for virtually all commercial applications. The limited choice of stable n-type (acceptor) organic semiconductor materials is one of the key factors that prevent the further improvement of organic PVs. TDA Research, Inc. (TDA) previously developed a new class of electron-deficient (n-type) conjugated polymers for use in organic light emitting diodes (OLEDs). During this project TDA in collaboration with the National Renewable Energy Laboratory (NREL) will incorporate these electron-deficient polymers into organic photovoltaics and investigate their performance. TDA Research, Inc. (TDA) is developing new materials and polymers to improve the performance of organic solar cells. Materials being developed at TDA include spin coated transparent conductors, charge injection layers, fullerene derivatives, electron-deficient polymers, and three-phase (fullerene/polythiophene/dye) active layer inks.

  9. Enhanced mechanical properties of low-surface energy thin films by simultaneous plasma polymerization of fluorine and epoxy containing polymers

    NASA Astrophysics Data System (ADS)

    Karaman, Mustafa; Uçar, Tuba

    2016-01-01

    Thin films of poly(2,2,3,4,4,4 hexafluorobutyl acrylate-glycidyl methacrylate) (P(HFBA-GMA) were deposited on different surfaces using an inductively coupled RF plasma reactor. Fluorinated polymer was used to impart hydrophobicity, whereas epoxy polymer was used for improved durability. The deposition at a low plasma power and temperature was suitable for the functionalization of fragile surfaces such as textile fabrics. The coated rough textile surfaces were found to be superhydrophobic with water contact angles greater than 150° due to the high retention of long fluorinated side chains. The hydrophobicity of the surfaces was observed to be stable after many exposures to ultrasonification tests, which is attributed to the mechanical durability of the films due to their epoxide functionality. FTIR and XPS analyses of the deposited films confirmed that the epoxide functionality of the polymers increased with increasing glycidyl methacrylate fraction in the reactor inlet. The modulus and hardness values of the films also increase with increasing epoxide functionality.

  10. Organic matter induced mobilization of polymer-coated silver nanoparticles from water-saturated sand.

    PubMed

    Yang, Xinyao; Yin, Ziyi; Chen, Fangmin; Hu, Jingjing; Yang, Yuesuo

    2015-10-01

    Mobilization of polymer-coated silver nanoparticles (AgNPs) by anionic surfactant (sodium dodecylbenzenesulphonate: SDBS), amino acid derivative (N-acetylcysteine: NAC), and chelate (ethylenediaminetetraacetic acid: EDTA) in water-saturated sand medium was explored based on carefully designed column tests. Exposure experiments monitoring the size evolution of polyvinylpyrrolidone (PVP) coated AgNPs in organic solutions confirm the capacity of SDBS, NAC and EDTA to partly displace PVP. Single Pulse Column Experiment (SPCE) results show both the PVP polymer and the silver core controlled AgNP deposition while the effect of the PVP was dominant. Results of Co-injected Pulse Column Experiments (CPCEs) where AgNP and SDBS or NAC were co-injected into the column following a very short mixing (<1 s) disprove our hypothesis that coating-alternation by particle associated organic would mobilize irreversibly deposited particles from the uncoated sand, while surface charge modification by adsorbed NAC was identified as a potential mobilizing mechanism for AgNP from the iron-oxide-coated sand. Triple Pulse Column Experiment (TPCE) results confirm that such a charging effect of the adsorbed organic molecules may enable SDBS and NAC to mobilize AgNPs from the iron-oxide-coated sands. TPCE results with five distinct levels of SDBS indicate that concentration-stimulated change in the SDBS format from an individual to a micelle significantly increased the mobilizing efficiency and site blockage of SDBS. Although being an electrolyte, EDTA did not mobilize AgNPs, as the case with SDBS or NAC, as it dissolved the iron oxides which in turn prevented EDTA adsorption on sand. The findings have implications for better understanding the behavior of polymer-coated nanoparticles in organic-presented groundwater systems, i.e., detachment-associated uncertainty in exposure prediction of the nanomaterials. PMID:26011614

  11. Organic matter induced mobilization of polymer-coated silver nanoparticles from water-saturated sand.

    PubMed

    Yang, Xinyao; Yin, Ziyi; Chen, Fangmin; Hu, Jingjing; Yang, Yuesuo

    2015-10-01

    Mobilization of polymer-coated silver nanoparticles (AgNPs) by anionic surfactant (sodium dodecylbenzenesulphonate: SDBS), amino acid derivative (N-acetylcysteine: NAC), and chelate (ethylenediaminetetraacetic acid: EDTA) in water-saturated sand medium was explored based on carefully designed column tests. Exposure experiments monitoring the size evolution of polyvinylpyrrolidone (PVP) coated AgNPs in organic solutions confirm the capacity of SDBS, NAC and EDTA to partly displace PVP. Single Pulse Column Experiment (SPCE) results show both the PVP polymer and the silver core controlled AgNP deposition while the effect of the PVP was dominant. Results of Co-injected Pulse Column Experiments (CPCEs) where AgNP and SDBS or NAC were co-injected into the column following a very short mixing (<1 s) disprove our hypothesis that coating-alternation by particle associated organic would mobilize irreversibly deposited particles from the uncoated sand, while surface charge modification by adsorbed NAC was identified as a potential mobilizing mechanism for AgNP from the iron-oxide-coated sand. Triple Pulse Column Experiment (TPCE) results confirm that such a charging effect of the adsorbed organic molecules may enable SDBS and NAC to mobilize AgNPs from the iron-oxide-coated sands. TPCE results with five distinct levels of SDBS indicate that concentration-stimulated change in the SDBS format from an individual to a micelle significantly increased the mobilizing efficiency and site blockage of SDBS. Although being an electrolyte, EDTA did not mobilize AgNPs, as the case with SDBS or NAC, as it dissolved the iron oxides which in turn prevented EDTA adsorption on sand. The findings have implications for better understanding the behavior of polymer-coated nanoparticles in organic-presented groundwater systems, i.e., detachment-associated uncertainty in exposure prediction of the nanomaterials.

  12. Specific features of microheterogeneous plasma produced by irradiation of a polymer aerogel target with an intense 500-ps-long laser pulse

    SciTech Connect

    Borisenko, N. G.; Merkul’ev, Yu. A.; Orekhov, A. S.; Chaurasia, S.; Tripathi, S.; Munda, D. S.; Dhareshwar, L. J.; Pimenov, V. G.; Sheveleva, E. E.

    2013-08-15

    The properties of microheterogeneous plasma produced by irradiation of a polymer aerogel target with an intense (10{sup 14} W/cm{sup 3}) short (0.5 ps) 1.064-μm laser pulse were studied. It is found that, even at plasma densities exceeding the critical density, a small fraction of the incident laser radiation penetrates through the plasma in which the processes of density and temperature equalization still take place. The intensification (as compared to plasmas produced from denser foams and solid films) of transport processes in such plasma along and across the laser beam can be caused by the initial microheterogeneity of the solid target. The replacement of a small (10% by mass) part of the polymer with copper nanoparticles leads to a nearly twofold increase in the intensity of the plasma X-ray emission.

  13. Ultrafast photophysics of pi-conjugated polymers for organic light emitting diode applications

    NASA Astrophysics Data System (ADS)

    Olejnik, Ella

    the main exciton photoinduced absorption band (PA1) show a variety of decay kinetics that result from various photoexcitations that contribute to the spectrum. Comparing the transient PM spectrum at 1 ns time delay to the CW PM shows the formation of triplet excitons, which is possible due to singlet fission of mAg (at 2.9 eV) into two triplets (2 X 1.4 eV). In the last part of this thesis we summarize our studies of organic light emitting diodes (OLED) devices based on a host/guest blend of Polyfluorene polymer that is mixed with various percentages of Ir(btp)2acac molecules. In this mixture the PFO (host) shows blue fluorescence, whereas the Ir-complex (guest) has red phosphorescence emission; thus OLED based on this mixture can serve as a `white OLED'. Since the PFO emission spectrum perfectly matches the absorption band of the Ir-complex, it induces an efficient energy transfer from the PFO host to the Ir-complex guest molecules, which we tried to time resolve by the transient PM method.

  14. Analysis of the low-pressure plasma pretreated polymer surface in terms of acid-base approach

    NASA Astrophysics Data System (ADS)

    Kraus, Eduard; Orf, Lukas; Baudrit, Benjamin; Heidemeyer, Peter; Bastian, Martin; Bonenberger, Ramona; Starostina, Irina; Stoyanov, Oleg

    2016-05-01

    We demonstrate the use of a modern wetting method for determining the acid-base properties of treated polymer surfaces for different plastics and adhesives. The effect of the surface treatment with low pressure plasma was evaluated from the viewpoint of acid-base approach with plastics polyoxymethylene (POM) and polyetheretherketone (PEEK). The correlations between the acid-base properties and the identified mechanical tensile strengths of adhesive bonded joints were evaluated and discussed. In the investigated range the determination coefficients for POM and PEEK were calculated to R2 = 0.93 and R2 = 0.97, respectively. These relatively high determination coefficients showed a good correlation between the mechanical strength and the acidity parameter ΔDshort for use in bonding technology for surface pretreatment of polymers with LPP.

  15. Centro-Apical Self-Organization of Organic Semiconductors in a Line-Printed Organic Semiconductor: Polymer Blend for One-Step Printing Fabrication of Organic Field-Effect Transistors

    PubMed Central

    Jin Lee, Su; Kim, Yong-Jae; Young Yeo, So; Lee, Eunji; Sun Lim, Ho; Kim, Min; Song, Yong-Won; Cho, Jinhan; Ah Lim, Jung

    2015-01-01

    Here we report the first demonstration for centro-apical self-organization of organic semiconductors in a line-printed organic semiconductor: polymer blend. Key feature of this work is that organic semiconductor molecules were vertically segregated on top of the polymer phase and simultaneously crystallized at the center of the printed line pattern after solvent evaporation without an additive process. The thickness and width of the centro-apically segregated organic semiconductor crystalline stripe in the printed blend pattern were controlled by varying the relative content of the organic semiconductors, printing speed, and solution concentrations. The centro-apical self-organization of organic semiconductor molecules in a printed polymer blend may be attributed to the combination of an energetically favorable vertical phase-separation and hydrodynamic fluids inside the droplet during solvent evaporation. Finally, a centro-apically phase-separated bilayer structure of organic semiconductor: polymer blend was successfully demonstrated as a facile method to form the semiconductor and dielectric layer for OFETs in one- step. PMID:26359068

  16. Centro-Apical Self-Organization of Organic Semiconductors in a Line-Printed Organic Semiconductor: Polymer Blend for One-Step Printing Fabrication of Organic Field-Effect Transistors.

    PubMed

    Lee, Su Jin; Kim, Yong-Jae; Yeo, So Young; Lee, Eunji; Lim, Ho Sun; Kim, Min; Song, Yong-Won; Cho, Jinhan; Lim, Jung Ah

    2015-01-01

    Here we report the first demonstration for centro-apical self-organization of organic semiconductors in a line-printed organic semiconductor: polymer blend. Key feature of this work is that organic semiconductor molecules were vertically segregated on top of the polymer phase and simultaneously crystallized at the center of the printed line pattern after solvent evaporation without an additive process. The thickness and width of the centro-apically segregated organic semiconductor crystalline stripe in the printed blend pattern were controlled by varying the relative content of the organic semiconductors, printing speed, and solution concentrations. The centro-apical self-organization of organic semiconductor molecules in a printed polymer blend may be attributed to the combination of an energetically favorable vertical phase-separation and hydrodynamic fluids inside the droplet during solvent evaporation. Finally, a centro-apically phase-separated bilayer structure of organic semiconductor: polymer blend was successfully demonstrated as a facile method to form the semiconductor and dielectric layer for OFETs in one- step.

  17. Organic Polymer Dots as Photocatalysts for Visible Light-Driven Hydrogen Generation.

    PubMed

    Wang, Lei; Fernández-Terán, Ricardo; Zhang, Lei; Fernandes, Daniel L A; Tian, Lei; Chen, Hong; Tian, Haining

    2016-09-26

    For the first time, organic semiconducting polymer dots (Pdots) based on poly[(9,9'-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,1',3} thiadiazole)] (PFBT) and polystyrene grafting with carboxyl-group-functionalized ethylene oxide (PS-PEG-COOH) are introduced as a photocatalyst towards visible-light-driven hydrogen generation in a completely organic solvent-free system. With these organic Pdots as the photocatalyst, an impressive initial rate constant of 8.3 mmol h(-1)  g(-1) was obtained for visible-light-driven hydrogen production, which is 5-orders of magnitude higher than that of pristine PFBT polymer under the same catalytic conditions. Detailed kinetics studies suggest that the productive electron transfer quench of the excited state of Pdots by an electron donor is about 40 %. More importantly, we also found that the Pdots can tolerate oxygen during catalysis, which is crucial for further application of this material for light-driven water splitting. PMID:27604393

  18. Direct photoetching of polymers using radiation of high energy density from a table-top extreme ultraviolet plasma source

    SciTech Connect

    Barkusky, Frank; Bayer, Armin; Peth, Christian; Mann, Klaus

    2009-01-01

    In order to perform material interaction studies with intense extreme ultraviolet (EUV) radiation, a Schwarzschild mirror objective coated with Mo/Si multilayers was adapted to a compact laser-driven EUV plasma source utilizing a solid Au target. By 10x demagnified imaging of the plasma a maximum pulse energy density of {approx}0.73 J/cm{sup 2} at a wavelength of 13.5 nm can be achieved in the image plane of the objective at a pulse duration of 8.8 ns. In this paper we present EUV photoetching rates measured for polymethyl methacrylate, polycarbonate, and polytetrafluoroethylene at various fluence levels. A linear dependence between etch depth and applied EUV pulse number could be observed without the necessity for any incubation pulses. By evaluating the slope of these data, etch rates were determined, revealing also a linear behavior for low fluences. A threshold energy density could not be observed. The slope of the linear etch regime as well as deviations from the linear trend at higher energy densities are discussed and compared to data known from deep UV laser ablation. Furthermore, the surface roughness of the structured polymers was measured by atomic force microscopy and compared to the nonirradiated polymer surface, indicating a rather smooth etch process (roughness increase of 20%-30%). The different shapes of the etch craters observed for the three polymers at high energy densities can be explained by the measured fluence dependence of the etch rates, having consequences for the proper use of polymer ablation for beam profiling of focused EUV radiation.

  19. Microtexturing of the conductive PEDOT:PSS polymer for superhydrophobic organic electrochemical transistors.

    PubMed

    Gentile, Francesco; Coppedè, Nicola; Tarabella, Giuseppe; Villani, Marco; Calestani, Davide; Candeloro, Patrizio; Iannotta, Salvatore; Di Fabrizio, Enzo

    2014-01-01

    Superhydrophobic surfaces are bioinspired, nanotechnology artifacts, which feature a reduced friction coefficient, whereby they can be used for a number of very practical applications including, on the medical side, the manipulation of biological solutions. In this work, we integrated superhydrophobic patterns with the conducting polymer PEDOT:PSS, one of the most used polymers in organic electronics because highly sensitive to ionized species in solution. In doing so, we combined geometry and materials science to obtain an advanced device where, on account of the superhydrophobicity of the system, the solutions of interest can be manipulated and, on account of the conductive PEDOT:PSS polymer, the charged molecules dispersed inside can be quantitatively measured. This original substrate preparation allowed to perform electrochemical measurements on ionized species in solution with decreasing concentration down to 10(-7) molar. Moreover, it was demonstrated the ability of the device of realizing specific, combined time and space resolved analysis of the sample. Collectively, these results demonstrate how a tight, interweaving integration of different disciplines can provide realistic tools for the detection of pathologies. The scheme here introduced offers breakthrough capabilities that are expected to radically improve both the pace and the productivity of biomedical research, creating an access revolution. PMID:24579079

  20. Microtexturing of the conductive PEDOT:PSS polymer for superhydrophobic organic electrochemical transistors.

    PubMed

    Gentile, Francesco; Coppedè, Nicola; Tarabella, Giuseppe; Villani, Marco; Calestani, Davide; Candeloro, Patrizio; Iannotta, Salvatore; Di Fabrizio, Enzo

    2014-01-01

    Superhydrophobic surfaces are bioinspired, nanotechnology artifacts, which feature a reduced friction coefficient, whereby they can be used for a number of very practical applications including, on the medical side, the manipulation of biological solutions. In this work, we integrated superhydrophobic patterns with the conducting polymer PEDOT:PSS, one of the most used polymers in organic electronics because highly sensitive to ionized species in solution. In doing so, we combined geometry and materials science to obtain an advanced device where, on account of the superhydrophobicity of the system, the solutions of interest can be manipulated and, on account of the conductive PEDOT:PSS polymer, the charged molecules dispersed inside can be quantitatively measured. This original substrate preparation allowed to perform electrochemical measurements on ionized species in solution with decreasing concentration down to 10(-7) molar. Moreover, it was demonstrated the ability of the device of realizing specific, combined time and space resolved analysis of the sample. Collectively, these results demonstrate how a tight, interweaving integration of different disciplines can provide realistic tools for the detection of pathologies. The scheme here introduced offers breakthrough capabilities that are expected to radically improve both the pace and the productivity of biomedical research, creating an access revolution.

  1. Organization of Nucleotides in Different Environments and the Formation of Pre-Polymers.

    PubMed

    Himbert, Sebastian; Chapman, Mindy; Deamer, David W; Rheinstädter, Maikel C

    2016-01-01

    RNA is a linear polymer of nucleotides linked by a ribose-phosphate backbone. Polymerization of nucleotides occurs in a condensation reaction in which phosphodiester bonds are formed. However, in the absence of enzymes and metabolism there has been no obvious way for RNA-like molecules to be produced and then encapsulated in cellular compartments. We investigated 5'-adenosine monophosphate (AMP) and 5'-uridine monophosphate (UMP) molecules confined in multi-lamellar phospholipid bilayers, nanoscopic films, ammonium chloride salt crystals and Montmorillonite clay, previously proposed to promote polymerization. X-ray diffraction was used to determine whether such conditions imposed a degree of order on the nucleotides. Two nucleotide signals were observed in all matrices, one corresponding to a nearest neighbour distance of 4.6 Å attributed to nucleotides that form a disordered, glassy structure. A second, smaller distance of 3.4 Å agrees well with the distance between stacked base pairs in the RNA backbone, and was assigned to the formation of pre-polymers, i.e., the organization of nucleotides into stacks of about 10 monomers. Such ordering can provide conditions that promote the nonenzymatic polymerization of RNA strands under prebiotic conditions. Experiments were modeled by Monte-Carlo simulations, which provide details of the molecular structure of these pre-polymers. PMID:27545761

  2. Organization of Nucleotides in Different Environments and the Formation of Pre-Polymers

    NASA Astrophysics Data System (ADS)

    Himbert, Sebastian; Chapman, Mindy; Deamer, David W.; Rheinstädter, Maikel C.

    2016-08-01

    RNA is a linear polymer of nucleotides linked by a ribose-phosphate backbone. Polymerization of nucleotides occurs in a condensation reaction in which phosphodiester bonds are formed. However, in the absence of enzymes and metabolism there has been no obvious way for RNA-like molecules to be produced and then encapsulated in cellular compartments. We investigated 5‧-adenosine monophosphate (AMP) and 5‧-uridine monophosphate (UMP) molecules confined in multi-lamellar phospholipid bilayers, nanoscopic films, ammonium chloride salt crystals and Montmorillonite clay, previously proposed to promote polymerization. X-ray diffraction was used to determine whether such conditions imposed a degree of order on the nucleotides. Two nucleotide signals were observed in all matrices, one corresponding to a nearest neighbour distance of 4.6 Å attributed to nucleotides that form a disordered, glassy structure. A second, smaller distance of 3.4 Å agrees well with the distance between stacked base pairs in the RNA backbone, and was assigned to the formation of pre-polymers, i.e., the organization of nucleotides into stacks of about 10 monomers. Such ordering can provide conditions that promote the nonenzymatic polymerization of RNA strands under prebiotic conditions. Experiments were modeled by Monte-Carlo simulations, which provide details of the molecular structure of these pre-polymers.

  3. Organization of Nucleotides in Different Environments and the Formation of Pre-Polymers

    PubMed Central

    Himbert, Sebastian; Chapman, Mindy; Deamer, David W.; Rheinstädter, Maikel C.

    2016-01-01

    RNA is a linear polymer of nucleotides linked by a ribose-phosphate backbone. Polymerization of nucleotides occurs in a condensation reaction in which phosphodiester bonds are formed. However, in the absence of enzymes and metabolism there has been no obvious way for RNA-like molecules to be produced and then encapsulated in cellular compartments. We investigated 5′-adenosine monophosphate (AMP) and 5′-uridine monophosphate (UMP) molecules confined in multi-lamellar phospholipid bilayers, nanoscopic films, ammonium chloride salt crystals and Montmorillonite clay, previously proposed to promote polymerization. X-ray diffraction was used to determine whether such conditions imposed a degree of order on the nucleotides. Two nucleotide signals were observed in all matrices, one corresponding to a nearest neighbour distance of 4.6 Å attributed to nucleotides that form a disordered, glassy structure. A second, smaller distance of 3.4 Å agrees well with the distance between stacked base pairs in the RNA backbone, and was assigned to the formation of pre-polymers, i.e., the organization of nucleotides into stacks of about 10 monomers. Such ordering can provide conditions that promote the nonenzymatic polymerization of RNA strands under prebiotic conditions. Experiments were modeled by Monte-Carlo simulations, which provide details of the molecular structure of these pre-polymers. PMID:27545761

  4. A Brief Survey of β-Detected NMR of Implanted 8Li+ in Organic Polymers

    NASA Astrophysics Data System (ADS)

    McGee, F. H.; McKenzie, I.; Buck, T.; Daley, C. R.; Forrest, J. A.; Harada, M.; Kiefl, R. F.; Levy, C. D. P.; Morris, G. D.; Pearson, M. R.; Sugiyama, J.; Wang, D.; MacFarlane, W. A.

    2014-12-01

    Unlike the positive muon, we expect the chemistry of the implanted 8Li+β-NMR probe in organic polymers to be simply that of the monovalent ion, but almost nothing is known about the NMR of isolated Li+ in this context. Here, we present a brief survey of 8Li+β-NMR in a variety of insulating polymers at high magnetic field, including polyimide, PET, polycarbonate, polystyrene and polyethylene oxide. In all cases, we find a large-amplitude, broad Lorentzian resonance near the Larmor frequency, consistent with the expected diamagnetic charge state. We also find remarkably fast spin-lattice relaxation rates 1/T1. There is very little dependence of either linewidth or 1/T1 on the proton density, the main source of nuclear dipolar magnetic fields, leading us to conclude the main contribution to both broadening and spin relaxation at room temperature is quadrupolar in origin. This behaviour is very different from crystalline insulators such as MgO and Al2O3, and suggests that 8Li+β-NMR will be an important probe of polymer dynamics. Additionally, we note dramatically different behaviour of one sample above its glass transition, motivating the construction of a high temperature spectrometer to enable further exploration at elevated temperature.

  5. Manipulating Magneto-Optic Properties of a Chiral Polymer by Doping with Stable Organic Biradicals.

    PubMed

    Lim, Chang-Keun; Cho, Min Ju; Singh, Ajay; Li, Qi; Kim, Won Jin; Jee, Hong Sub; Fillman, Kathlyn L; Carpenter, Stephanie H; Neidig, Michael L; Baev, Alexander; Swihart, Mark T; Prasad, Paras N

    2016-09-14

    We report the first example of tuning the large magneto-optic activity of a chiral polymer by addition of stable organic biradicals. The spectral dispersion of Verdet constant, which quantifies magneto-optic response, differs substantially between the base polymer and the nanocomposite. We employed a microscopic model, supported by atomistic calculations, to rationalize the behavior of this nanocomposite system. The suggested mechanism involves magnetic coupling between helical conjugated polymer fibrils, with spatially delocalized helical π-electron density, and the high density of spin states provided by the biradical dopants, which leads to synergistic enhancement of magneto-optic response. Our combined experimental and theoretical studies reveal that the manipulation of magnetic coupling in this new class of magneto-optic materials offers an opportunity to tailor the magnitude, sign, and spectral dispersion of the Verdet constant over a broad range of wavelengths, from the UV to the near-IR. This provides a new strategy for creating conformable materials with extraordinary magneto-optic activity, which can ultimately enable new applications requiring spatially and temporally resolved measurement of extremely weak magnetic fields. In particular, magneto-optic materials, presently employed in technologies like optical isolators and optical circulators, could be used in ultrasensitive optical magnetometers. This, in turn, could open a path toward mapping of brain activity via optical magnetoencephalography. PMID:27518762

  6. Multi-Organ Contribution to the Metabolic Plasma Profile Using Hierarchical Modelling

    PubMed Central

    Torell, Frida; Bennett, Kate; Cereghini, Silvia; Rännar, Stefan; Lundstedt-Enkel, Katrin; Moritz, Thomas; Haumaitre, Cecile; Trygg, Johan; Lundstedt, Torbjörn

    2015-01-01

    Hierarchical modelling was applied in order to identify the organs that contribute to the levels of metabolites in plasma. Plasma and organ samples from gut, kidney, liver, muscle and pancreas were obtained from mice. The samples were analysed using gas chromatography time-of-flight mass spectrometry (GC TOF-MS) at the Swedish Metabolomics centre, Umeå University, Sweden. The multivariate analysis was performed by means of principal component analysis (PCA) and orthogonal projections to latent structures (OPLS). The main goal of this study was to investigate how each organ contributes to the metabolic plasma profile. This was performed using hierarchical modelling. Each organ was found to have a unique metabolic profile. The hierarchical modelling showed that the gut, kidney and liver demonstrated the greatest contribution to the metabolic pattern of plasma. For example, we found that metabolites were absorbed in the gut and transported to the plasma. The kidneys excrete branched chain amino acids (BCAAs) and fatty acids are transported in the plasma to the muscles and liver. Lactic acid was also found to be transported from the pancreas to plasma. The results indicated that hierarchical modelling can be utilized to identify the organ contribution of unknown metabolites to the metabolic profile of plasma. PMID:26086868

  7. Low-Temperature Seebeck Coefficients for Polaron-Driven Thermoelectric Effect in Organic Polymers.

    PubMed

    de Oliveira Neto, Pedro Henrique; da Silva Filho, Demétrio A; Roncaratti, Luiz F; Acioli, Paulo H; E Silva, Geraldo Magela

    2016-07-14

    We report the results of electronic structure coupled to molecular dynamics simulations on organic polymers subject to a temperature gradient at low-temperature regimes. The temperature gradient is introduced using a Langevin-type dynamics corrected for quantum effects, which are very important in these systems. Under this condition we were able to determine that in these no-impurity systems the Seebeck coefficient is in the range of 1-3 μV/K. These results are in good agreement with reported experimental results under the same low-temperature conditions.

  8. Principles and Applications of Solid Polymer Electrolyte Reactors for Electrochemical Hydrodehalogenation of Organic Pollutants

    NASA Astrophysics Data System (ADS)

    Cheng, Hua; Scott, Keith

    The ability to re-cycle halogenated liquid wastes, based on electrochemical hydrodehalogenation (EHDH), will provide a significant economic advantage and will reduce the environmental burden in a number of processes. The use of a solid polymer electrolyte (SPE) reactor is very attractive for this purpose. Principles and features of electrochemical HDH technology and SPE EHDH reactors are described. The SPE reactor enables selective dehalogenation of halogenated organic compounds in both aqueous and non-aqueous media with high current efficiency and low energy consumption. The influence of operating conditions, including cathode material, current density, reactant concentration and temperature on the HDH process and its stability are examined.

  9. Structure-Property Relations in Polymer:Fullerene Blends for Organic Solar Cells.

    PubMed

    Banerji, Natalie

    2016-01-01

    Organic solar cells consist of thin films combining an electron donor (often a conjugated polymer) with an electron acceptor (often a fullerene derivative), in a blend commonly referred to as bulk heterojunction material. Charge separation between the donor and the acceptor leads to the generation of carriers, which can be extracted from photovoltaic devices in the form of photocurrent. The generation mechanism of free, extractable charges has caused a lot of controversial discussion in literature. Our research has shown that all the steps involved in charge generation are strongly dependent on the arrangement of the donor and the acceptor (i.e. the structure) of the bulk heterojunction. PMID:27561613

  10. Structure dependence of lasing action in organic polymer films on DFB gratings for dinitrotoluene vapor detection.

    PubMed

    Liu, Qiufeng; Qiu, Keqiang; He, Shengnan; Liu, Honglin; Liu, Zhengkun; Hong, Yilin; Fu, Shaojun

    2016-06-20

    Structure effects of distributed feedback (DFB) gratings on lasing action have been investigated for detecting explosive vapors. For the first time, we have established the optimized profiles of the DFB grating, and given the theoretical path to design its structure for amplified spontaneous emission (ASE) of organic polymer films based on Bragg conditions. A poly(p-phenylene ethynylene) (PPE) film can realize detection of dinitrotoluene (DNT) vapors in 2 min with a reduced excitation threshold of 26 mJ cm(-2) by using a simple and common 405 nm laser. PMID:27277339

  11. Studies of interactions between conducting polymer and organic vapors, applications to chemical sensing

    SciTech Connect

    Josowicz, M.; Topart, P.; Cabala, R.

    1993-05-01

    In order to understand the physicochemical mechanism involved in the organic semiconductor charge-transfer processes occurring upon doping of the films with vapor molecules different experimental approaches much be taken. The effect of vapor diffusion into the electrochemically deposited poly(pyrrole), PP and poly(N-vinylcarbazole), PNVCz, films was investigated by monitoring the mass change of the exposed polymer, absorbance changes in the absorption spectra, and the work function change due to the modulation of the Fermi level in the material. An important step in that investigation was to establish the link between the distribution of the active dopant within the surface and the bulk of the material (1).

  12. Molecular simulation of dispersion and mechanical stability of organically modified layered silicates in polymer matrices

    NASA Astrophysics Data System (ADS)

    Fu, Yao-Tsung

    The experimental analysis of nanometer-scale separation processes and mechanical properties at buried interfaces in nanocomposites has remained difficult. We have employed molecular dynamics simulation in relation to available experimental data to alleviate such limitations and gain insight into the dispersion and mechanical stability of organically modified layered silicates in hydrophobic polymer matrices. We analyzed cleavage energies of various organically modified silicates as a function of the cation exchange capacity, surfactant head group chemistry, and chain length using MD simulations with the PCFF-PHYLLOSILICATE force field. The range of the cleavage energy is between 25 and 210 mJ/m2 upon the molecular structures and packing of surfactants. As a function of chain length, the cleavage energy indicates local minima for interlayer structures comprised of loosely packed layers of alkyl chains and local maxima for interlayer structures comprised of densely packed layers of alkyl chains between the layers. In addition, the distribution of cationic head groups between the layers in the equilibrium state determines whether large increases in cleavage energy due to Coulomb attraction. We have also examined mechanical bending and failure mechanisms of layered silicates on the nanometer scale using molecular dynamics simulation in comparison to a library of TEM data of polymer nanocomposites. We investigated the energy of single clay lamellae as a function of bending radius and different cation density. The layer energy increases particularly for bending radii below 20 nm and is largely independent of cation exchange capacity. The analysis of TEM images of agglomerated and exfoliated aluminosilicates of different CEC in polymer matrices at small volume fractions showed bending radii in excess of 100 nm due to free volumes in the polymer matrix. At a volume fraction >5%, however, bent clay layers were found with bending radii <20 nm and kinks as a failure mechanism

  13. Structure-Property Relations in Polymer:Fullerene Blends for Organic Solar Cells.

    PubMed

    Banerji, Natalie

    2016-01-01

    Organic solar cells consist of thin films combining an electron donor (often a conjugated polymer) with an electron acceptor (often a fullerene derivative), in a blend commonly referred to as bulk heterojunction material. Charge separation between the donor and the acceptor leads to the generation of carriers, which can be extracted from photovoltaic devices in the form of photocurrent. The generation mechanism of free, extractable charges has caused a lot of controversial discussion in literature. Our research has shown that all the steps involved in charge generation are strongly dependent on the arrangement of the donor and the acceptor (i.e. the structure) of the bulk heterojunction.

  14. Evaluation of Metal-Organic Frameworks and Porous Polymer Networks for CO2 -Capture Applications.

    PubMed

    Verdegaal, Wolfgang M; Wang, Kecheng; Sculley, Julian P; Wriedt, Mario; Zhou, Hong-Cai

    2016-03-21

    This manuscript presents experimental data for 20 adsorption materials (metal-organic frameworks, porous polymer networks, and Zeolite-5A), including CO2 and N2 isotherms and heat capacities. With input from only experimental data, working capacities per energy for each material were calculated. Furthermore, by running seven different carbon-capture scenarios in which the initial flue-gas composition and process temperature was systematically changed, we present a range of performances for each material and quantify how sensitive each is to these varying parameters. The presented calculations provide researchers with a tool to investigate promising carbon-capture materials more easily and completely.

  15. Cell patterning via linker-free protein functionalization of an organic conducting polymer (polypyrrole) electrode.

    PubMed

    Bax, Daniel V; Tipa, Roxana S; Kondyurin, Alexey; Higgins, Michael J; Tsoutas, Kostadinos; Gelmi, Amy; Wallace, Gordon G; McKenzie, David R; Weiss, Anthony S; Bilek, Marcela M M

    2012-07-01

    The interaction of proteins and cells with polymers is critical to their use in scientific and medical applications. In this study, plasma immersion ion implantation (PIII) was used to modify the surface of the conducting polymer, polypyrrole, which possesses electrical properties. PIII treatment enabled persistent, covalent binding of the cell adhesive protein, tropoelastin, without employing chemical linking molecules. In contrast tropoelastin was readily eluted from the untreated surface. Through this differential persistence of binding, surface bound tropoelastin supported cell adhesion and spreading on the PIII treated but not the untreated polypyrrole surface. The application of a steel shadow mask during PIII treatment allowed for spatial definition of tropoelastin exclusively to PIII treated regions. The general applicability of this approach to other extracellular matrix proteins was illustrated using collagen I, which displayed similar results to tropoelastin but required extended washing conditions. This approach allowed fine patterning of cell adhesion and spreading to tropoelastin and collagen, specifically on PIII treated polypyrrole regions. We therefore present a methodology to alter the functionality of polypyrrole surfaces, generating surfaces that can spatially control cellular interactions through protein functionalization with the potential for electrical stimulation.

  16. Ag/SiO(x)C(y) plasma polymer coating for antimicrobial protection of fracture fixation devices.

    PubMed

    Khalilpour, Poroshat; Lampe, Kai; Wagener, Michael; Stigler, Brigitte; Heiss, Christian; Ullrich, Matthias S; Domann, Eugen; Schnettler, Reinhard; Alt, Volker

    2010-07-01

    Implant-related infections are often devastating situations in orthopaedic trauma surgery particularly if multiresistant bacteria are involved. Protection of the implant surface by an antimicrobial coating exhibiting activity against multiresistant bacterial strains is of high interest. Aim of this study was to investigate the antimicrobial effects of an Ag/SiO(x)C(y) plasma polymer coating for fracture fixation devices, such as nails, plates, and external fixators, including tests against methicillin-resistant Staphylococcus aureus (MRSA) and its biocompatibility. The antimicrobial activity of the coating deposited onto 12 x 3 mm(2) stainless steel implants was tested in vitro against Staphylococcus aureus, Staphylococcus epidermidis, and MRSA using different testing methods (ASTM E-2810, JIS Z 2801, proliferation assay). Additionally, the coated devices were implanted into the paravertebral muscle of rabbits and explanted after 2, 7, 14, and 28 days to test the remaining ex vivo antimicrobial activity. For biocompatibility assessment the Ag/SiO(x)C(y) plasma polymer coating was tested in vitro according to ISO 10993-5. The Ag/SiO(x)C(y) coating exhibited excellent antimicrobial activity against all tested bacterial strains in all three in vitro tests. Ex vivo testing proved suppression of more than 99.9 % of bacterial proliferation by the coating compared to non-coated samples even after 28 days. ISO 10993-5 showed good biocompatibility of the coating without any indications of cytotoxic effects. In summary, Ag/SiO(x)C(y) plasma polymer coating showed excellent antimicrobial activity including effectiveness against MRSA and good in vitro biocompatibility. Therefore, it possesses high potential as a prophylactic agent in orthopaedic trauma surgery.

  17. Real-time x-ray scattering study of the initial growth of organic crystals on polymer brushes

    SciTech Connect

    An, Sung Yup; Ahn, Kwangseok; Kim, Doris Yangsoo; Lee, Dong Ryeol; Lee, Hyun-Hwi; Cho, Jeong Ho

    2014-04-21

    We studied the early-stage growth structures of pentacene organic crystals grown on polymer brushes using real-time x-ray scattering techniques. In situ x-ray reflectivity and atomic force microscopy analyses revealed that at temperatures close to the glass transition temperature of polymer brush, the pentacene overlayer on a polymer brush film showed incomplete condensation and 3D island structures from the first monolayer. A growth model based on these observations was used to quantitatively analyze the real-time anti-Bragg x-ray scattering intensities measured during pentacene growth to obtain the time-dependent layer coverage of the individual pentacene monolayers. The extracted total coverage confirmed significant desorption and incomplete condensation in the pentacene films deposited on the polymer brushes. These effects are ascribed to the change in the surface viscoelasticity of the polymer brushes around the glass transition temperature.

  18. Plasma Meets Chemistry: Combined Methods for Tailored Interface Design in Metal-Polymer Composites by Selective Chemical Reactions on Plasma Modified Surfaces

    NASA Astrophysics Data System (ADS)

    Mix, R.; Hielscher, S.; Beck, U.; Friedrich, J. F.

    2012-12-01

    The applicability of polymer-metal composites is mainly determined by the durability of the adhesive strength between both components. Aluminium (Al) deposited on polypropylene (PP) exemplifies different options of interface design. By deposition of plasma polymers on PP the effect of the type of the functionality was investigated. Spacer insertion was accomplished to position the functional group away from the topmost surface. A further kind of interface design involved a partial condensation of functional groups. Hydroxyl and carboxyl groups were most effective to improve adhesion in Al-PP systems. Approximately 7-10 carboxyl or 25-27 hydroxyl groups per 100 C atoms were necessary to increase the peel strength up to ~700 N/m. In this range, the failure of the composite propagated along the interface Al-tape (no peeling of the metal). Spacer molecules between surface and functional groups provoked the effect that the number of needed functional groups for maximum adhesion was strongly reduced. Linking of the functional groups resulted in non-peelable Al-PP laminates. Two adhesion tests were applied - the peel test and the centrifuge technology. For PP foils modified with chemically bonded and additionally linked silanol groups (no peeling) an adhesive strength of (2.5 ± 0.2) N/mm2 was determined by centrifuge technology. XPS inspection of both fracture surfaces indicated a sub-surface failure in the polymer.

  19. Production of organic compounds in plasmas: A comparison among electric sparks, laser-induced plasmas and UV light

    NASA Technical Reports Server (NTRS)

    Scattergood, T. W.; Mckay, C. P.; Borucki, W. J.; Giver, L. P.; Vanghyseghem, H.; Parris, J. E.; Miller, S. L.

    1991-01-01

    In order to study the production of organic compounds in plasmas (and shocks), various mixtures of N2, CH4, and H2, modeling the atmosphere of Titan, were exposed to discrete sparks, laser-induced plasmas (LIP) and ultraviolet light. The yields of HCN and simple hydrocarbons were measured and compared to those calculated from a simple quenched thermodynamic equilibrium model. The agreement between experiment and theory was fair for HCN and C2H2. However, the yields of C2H6 and other hydrocarbons were much higher than those predicted by the model. Our experiments suggest that photolysis by ultraviolet light from the plasma is an important process in the synthesis. This was confirmed by the photolysis of gas samples exposed to the light, but not to the plasma or shock waves. The results of these experiments demonstrate that, in addition to the well-known efficient synthesis of organic compounds in plasmas, the yields of saturated species, e.g., ethane, may be higher than predicted by theory and that LIP provide a convenient and clean way of simulating planetary lightning and impact plasmas in the laboratory.

  20. An electrocyclic strategy to poly(triarylmethyl radical) polymers: Potential organic ferromagnets

    SciTech Connect

    Morelli, J.P.

    1992-01-01

    Recent interest in organic ferromagnetism has been stimulated by the idea that large poly(triarylmethyl radical) polymers in which the radical centers are connected by [open quotes]meta[close quotes]-aryl groups may possess ferromagnetic properties. However, synthesis of these polyradicals has been limited by stepwise methods that are unsuitable for the preparation of large polymers. This limitation represents a primary challenge confronting the field. The authors have developed the first polymeric strategy to poly (m-triarylmethyl radical) precursors that involves an electrocyclic formation of the [open quotes]meta[close quotes]-substituted triarylmethyl chloride repeating unit from a polypropynol precursor. Poly[(E)-6-[beta]-chloroethenyl-1,3-phenylene-1-phenylpropynol-1,3-ylene] was prepared by palladium-catalyzed coupling of a bifunctional acetylene-aryl iodide monomer. The stable polymer reacted with thionyl chloride to form an unstable polychloroallene intermediate that underwent an electrocyclic conversion to the polyradical precursor, poly(1-chloro-2,7-naphthalenechlorobenzylidene). The reduced polyradicals exhibited properties of radical-radical coupling, and preparation of a second generation polymer that would overcome this problem has been initiated. The polymeric strategy was based on model studies that showed that (E)-3-(2-[beta]-chloroethenylphenyl)-1,1-diphenylpropynol, when converted to the corresponding chloroallene with thionyl chloride, underwent an electrocyclic conversion to [beta]-(1-chlornaphthyl)diphenylmethyl chloride. The strategy expanded upon the use of triarylpropynes as precursors to triarylmethyl chlorides, and extension of both approaches to higher analogs was demonstrated with dimeric systems. The electrocyclic processes were found to occur only for the trans-vinyl chlorides; the cis-isomers were found to undergo an alternative concerted cyclization to benzofluorene products.

  1. Relaxed Plasma Equilibria and Entropy-Related Plasma Self-Organization Principles

    NASA Astrophysics Data System (ADS)

    Dewar, Robert L.; Hole, Matthew J.; McGann, Mathew; Mills, Ruth; Hudson, Stuart R.

    2008-12-01

    The concept of plasma relaxation as a constrained energy minimization is reviewed. Recent work by the authors on generalizing this approach to partially relaxed threedimensional plasma systems in a way consistent with chaos theory is discussed, with a view to clarifying the thermodynamic aspects of the variational approach used. Other entropy-related approaches to finding long-time steady states of turbulent or chaotic plasma systems are also briefly reviewed.

  2. Plasma-catalyst coupling for volatile organic compound removal and indoor air treatment: a review

    NASA Astrophysics Data System (ADS)

    Thevenet, F.; Sivachandiran, L.; Guaitella, O.; Barakat, C.; Rousseau, A.

    2014-06-01

    The first part of the review summarizes the problem of air pollution and related air-cleaning technologies. Volatile organic compounds in particular have various effects on health and their abatement is a key issue. Different ways to couple non-thermal plasmas with catalytic or adsorbing materials are listed. In particular, a comparison between in-plasma and post-plasma coupling is made. Studies dealing with plasma-induced heterogeneous reactivity are analysed, as well as the possible modifications of the catalyst surface under plasma exposure. As an alternative to the conventional and widely studied plasma-catalyst coupling, a sequential approach has been recently proposed whereby pollutants are first adsorbed onto the material, then oxidized by switching on the plasma. Such a sequential approach is reviewed in detail.

  3. Periodic Phenomena In Laser-Ablation Plasma Plumes: A Self-Organization Scenario

    SciTech Connect

    Gurlui, S.; Sanduloviciu, M.; Mihesan, C.; Ziskind, M.; Focsa, C.

    2006-01-15

    Experimental evidence of the appearance of a proper periodic dynamics in a plasma plume created by pulsed laser ablation is considered as a hint for the presence of a self-organization scenario that explains similar phenomena observed in plasma diodes.

  4. Ultrathin Polymer Membranes with Patterned, Micrometric Pores for Organs-on-Chips.

    PubMed

    Pensabene, Virginia; Costa, Lino; Terekhov, Alexander Y; Gnecco, Juan S; Wikswo, John P; Hofmeister, William H

    2016-08-31

    The basal lamina or basement membrane (BM) is a key physiological system that participates in physicochemical signaling between tissue types. Its formation and function are essential in tissue maintenance, growth, angiogenesis, disease progression, and immunology. In vitro models of the BM (e.g., Boyden and transwell chambers) are common in cell biology and lab-on-a-chip devices where cells require apical and basolateral polarization. Extravasation, intravasation, membrane transport of chemokines, cytokines, chemotaxis of cells, and other key functions are routinely studied in these models. The goal of the present study was to integrate a semipermeable ultrathin polymer membrane with precisely positioned pores of 2 μm diameter in a microfluidic device with apical and basolateral chambers. We selected poly(l-lactic acid) (PLLA), a transparent biocompatible polymer, to prepare the semipermeable ultrathin membranes. The pores were generated by pattern transfer using a three-step method coupling femtosecond laser machining, polymer replication, and spin coating. Each step of the fabrication process was characterized by scanning electron microscopy to investigate reliability of the process and fidelity of pattern transfer. In order to evaluate the compatibility of the fabrication method with organs-on-a-chip technology, porous PLLA membranes were embedded in polydimethylsiloxane (PDMS) microfluidic devices and used to grow human umbilical vein endothelial cells (HUVECS) on top of the membrane with perfusion through the basolateral chamber. Viability of cells, optical transparency of membranes and strong adhesion of PLLA to PDMS were observed, thus confirming the suitability of the prepared membranes for use in organs-on-a-chip devices. PMID:27513606

  5. Controlling Internal Organization of Multilayer Poly(methacrylic acid) Hydrogels with Polymer Molecular Weight

    DOE PAGES

    Kozlovskaya, Veronika; Zavgorodnya, Oleksandra; Ankner, John F.; Kharlampieva, Eugenia

    2015-11-16

    Here, we report on tailoring the internal architecture of multilayer-derived poly(methacrylic acid) (PMAA) hydrogels by controlling the molecular weight of poly(N-vinylpyrrolidone) (PVPON) in hydrogen-bonded (PMAA/PVPON) layer-by-layer precursor films. The hydrogels are produced by cross-linking PMAA in the spin-assisted multilayers followed by PVPON release. We found that the thickness, morphology, and architecture of hydrogen-bonded films and the corresponding hydrogels are significantly affected by PVPON chain length. For all systems, an increase in PVPON molecular weight from Mw = 2.5 to 1300 kDa resulted in increased total film thickness. We also show that increasing polymer Mw smooths the hydrogen-bonded film surfaces butmore » roughens those of the hydrogels. Using deuterated dPMAA marker layers in neutron reflectometry measurements, we found that hydrogen-bonded films reveal a high degree of stratification which is preserved in the cross-linked films. We observed dPMAA to be distributed more widely in the hydrogen-bonded films prepared with small Mw PVPON due to the greater mobility of short-chain PVPON. Furthermore, these variations in the distribution of PMAA are erased after cross-linking, resulting in a distribution of dPMAA over about two bilayers for all Mw but being somewhat more widely distributed in the films templated with higher Mw PVPON. Finally, our results yield new insights into controlling the organization of nanostructured polymer networks using polymer molecular weight and open opportunities for fabrication of thin films with well-organized architecture and controllable function.« less

  6. Controlling Internal Organization of Multilayer Poly(methacrylic acid) Hydrogels with Polymer Molecular Weight

    SciTech Connect

    Kozlovskaya, Veronika; Zavgorodnya, Oleksandra; Ankner, John F.; Kharlampieva, Eugenia

    2015-11-16

    Here, we report on tailoring the internal architecture of multilayer-derived poly(methacrylic acid) (PMAA) hydrogels by controlling the molecular weight of poly(N-vinylpyrrolidone) (PVPON) in hydrogen-bonded (PMAA/PVPON) layer-by-layer precursor films. The hydrogels are produced by cross-linking PMAA in the spin-assisted multilayers followed by PVPON release. We found that the thickness, morphology, and architecture of hydrogen-bonded films and the corresponding hydrogels are significantly affected by PVPON chain length. For all systems, an increase in PVPON molecular weight from Mw = 2.5 to 1300 kDa resulted in increased total film thickness. We also show that increasing polymer Mw smooths the hydrogen-bonded film surfaces but roughens those of the hydrogels. Using deuterated dPMAA marker layers in neutron reflectometry measurements, we found that hydrogen-bonded films reveal a high degree of stratification which is preserved in the cross-linked films. We observed dPMAA to be distributed more widely in the hydrogen-bonded films prepared with small Mw PVPON due to the greater mobility of short-chain PVPON. Furthermore, these variations in the distribution of PMAA are erased after cross-linking, resulting in a distribution of dPMAA over about two bilayers for all Mw but being somewhat more widely distributed in the films templated with higher Mw PVPON. Finally, our results yield new insights into controlling the organization of nanostructured polymer networks using polymer molecular weight and open opportunities for fabrication of thin films with well-organized architecture and controllable function.

  7. A Compact Plasma Flow-Bubbler for Decomposition of Organic compounds and Sterilization

    NASA Astrophysics Data System (ADS)

    Yoshiki, Hiroyuki; Ishikawa, Fukuto; Igarashi, Yu; Sugawara, Tetuya

    2015-09-01

    Recently, Plasma production in and in contact with liquid has attracted much attention because of their applications to degradation of organic compounds, sterilization, water purification. UV, electron, ion and radical flows originated from a plasma and also shock wave induce physical and chemical reaction in a liquid, for example oxidation-reduction, electrolysis and reactive species production in a water. In particular, various reactive oxygen/nitrogen species generated at the plasma-liquid interface play an important role in oxidation and degradation of organic pollutants and bacteria. We have proposed the mild water treatment by ejecting the atmospheric-pressure μ plasma (AP μP) flow into a water using a microbubble aerator or a porous ceramics bubbler. In this study, a compact plasma flow-bubbler made up of a μplasma source and a porous ceramics has been developed for the applications of water purification and sterilization. AP μP is generated between a thin metal pipe electrode and a GND plate by a pulsed high voltage, so that the O2 μ plasma can be obtained without adding He and Ar gases. Plasma flow is ejected into the water through a porous ceramics. Decolorization of an indigo carmine solution strongly depended on O2 flow rate. Chemical probe method using terephthalic acid revealed that OH radicals are produced by the O2 plasma gas bubbling. The inactivation for E. coli, Bacillus subtilis was attained by the O2 plasma gas bubbling.

  8. A Challenge Beyond Bottom Cells: Top-Illuminated Flexible Organic Solar Cells with Nanostructured Dielectric/Metal/Polymer (DMP) Films.

    PubMed

    Ham, Juyoung; Dong, Wan Jae; Park, Jae Yong; Yoo, Chul Jong; Lee, Illhwan; Lee, Jong-Lam

    2015-07-15

    Top-illuminated flexible organic solar cells with a high power conversion efficiency (≈6.75%) are fabricated using a dielectric/metal/polymer (DMP) electrode. Employing a polymer layer (n = 1.49) makes it possible to show the high transmittance, which is insensitive to film thickness, and the excellent haze induced by well-ordered nanopatterns on the DMP electrode, leading to a 28% of enhancement in efficiency compared to bottom cells.

  9. Poly(exTTF): a novel redox-active polymer as active material for li-organic batteries.

    PubMed

    Häupler, Bernhard; Burges, René; Friebe, Christian; Janoschka, Tobias; Schmidt, Daniel; Wild, Andreas; Schubert, Ulrich S

    2014-08-01

    The first polymer bearing exTTF units intended for the use in electrical charge storage is presented. The polymer undergoes a redox reaction involving two electrons at -0.20 V vs Fc/Fc(+) and is applied as active cathode material in a Li-organic battery. The received coin cells feature a theoretical capacity of 132 mAh g(-1) , a cell potential of 3.5 V, and a lifetime exceeding more than 250 cycles.

  10. Plasma-modified nitric oxide-releasing polymer films exhibit time-delayed 8-log reduction in growth of bacteria.

    PubMed

    Mann, Michelle N; Neufeld, Bella H; Hawker, Morgan J; Pegalajar-Jurado, Adoracion; Paricio, Lindsey N; Reynolds, Melissa M; Fisher, Ellen R

    2016-01-01

    Tygon(®) and other poly(vinyl chloride)-derived polymers are frequently used for tubing in blood transfusions, hemodialysis, and other extracorporeal circuit applications. These materials, however, tend to promote bacterial proliferation which contributes to the high risk of infection associated with device use. Antibacterial agents, such as nitric oxide donors, can be incorporated into these materials to eliminate bacteria before they can proliferate. The release of the antimicrobial agent from the device, however, is challenging to control and sustain on timescales relevant to blood transport procedures. Surface modification techniques can be employed to address challenges with controlled drug release. Here, surface modification using H2O (v) plasma is explored as a potential method to improve the biocompatibility of biomedical polymers, namely, to tune the nitric oxide-releasing capabilities from Tygon films. Film properties are evaluated pre- and post-treatment by contact angle goniometry, x-ray photoelectron spectroscopy, and optical profilometry. H2O (v) plasma treatment significantly enhances the wettability of the nitric-oxide releasing films, doubles film oxygen content, and maintains surface roughness. Using the kill rate method, the authors determine both treated and untreated films cause an 8 log reduction in the population of both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. Notably, however, H2O (v) plasma treatment delays the kill rate of treated films by 24 h, yet antibacterial efficacy is not diminished. Results of nitric oxide release, measured via chemiluminescent detection, are also reported and correlated to the observed kill rate behavior. Overall, the observed delay in biocidal agent release caused by our treatment indicates that plasma surface modification is an important route toward achieving controlled drug release from polymeric biomedical devices. PMID:27440395

  11. High Resolution Imaging of Defect Structures in Polymer and Organic Molecular Crystals

    NASA Astrophysics Data System (ADS)

    Martin, David

    2003-03-01

    We have been developing techniques for the low dose High Resolution Electron Microscopy (HREM) imaging of defect structures in polymer and organic molecular crystals. We have examined a variety of technologically important materials systems including rigid-rod polymers, poly(imides), poly(diacetylenes), poly(bisthiazoles), poly(bisoxazoles), and aromatic polyamides such as poly(paraphenylene terephthalamide) (PPTA or Kevlar(R)) and poly(metaphenylene diisophthalamide) (MPDI or Nomex(R)). These studies have made it possible for us to image the molecular reorganization in the vicinity of dislocations, surfaces, and grain boundaries. We have also learned about the micromechanisms of lattice bending and twisting. Most recently we have been examining the microstructure of pentacene, a highly-crystalline conjugated organic small molecule that is of interest for making flexible electronic devices such as thin-film transistors. We have also been examing the utility of low voltage techniques using a table-top sized electron microscope that operates near 5 kV.

  12. Hydrophobization of polymer particles by tetrafluoromethane (CF4) plasma irradiation using a barrel-plasma-treatment system

    NASA Astrophysics Data System (ADS)

    Matsubara, Keisuke; Danno, Masato; Inoue, Mitsuhiro; Nishizawa, Hideki; Honda, Yuji; Abe, Takayuki

    2013-11-01

    In this study, tetrafluoromethane (CF4) plasma-treatments of polymethylmethacrylate (PMMA) powder were performed using a polygonal barrel-plasma-treatment system to improve the PMMA's hydrophobicity. Characterization of the treated samples showed that the PMMA particle surfaces were fluorinated by the CF4 treatment. The smooth surfaces of the particles changed into nano-sized worm-like structures after the plasma-treatment. The hydrophobicity of the treated PMMA samples was superior to that of the untreated samples. It was noted that the hydrophobicity of the treated samples and the surface fluorination level depended on the plasma-treatment time and radiofrequency (RF) power; high RF power increased the sample temperature, which in turn decreased the hydrophobicity of the treated samples and the surface fluorination because of the thermal decomposition of PMMA. The water-repellent effects were evaluated by using paper towels to show the application of the plasma-treated PMMA particles, with the result that the paper towel coated with the treated sample was highly water-repellent.

  13. Thiophene fused azacoronenes: regioselective synthesis, self organization, charge transport, and its incorporation in conjugated polymers

    DOEpatents

    Liu, Yi; He, Bo

    2015-09-15

    A regioselective synthesis of an azacoronene fused with two peripheral thiophene groups has been realized through a concise synthetic route. The resulting thienoazacoronene (TAC) derivatives show high degree of self-organization in solution, in single crystals, in the bulk, and in spuncast thin films. Spuncast thin film field-effect transistors of the TACs exhibited mobilities up to 0.028 cm.sup.2V.sup.-1 S.sup.-1, which is among the top field effect mobilities for solution processed discotic materials. Organic photovoltaic devices using TAC-containing conjugated polymers as the donor material exhibited a high open-circuit voltage of 0.89 V, which was ascribable to TAC's low-lying highest occupied molecular orbital energy level.

  14. Determining the optimum morphology in high-performance polymer-fullerene organic photovoltaic cells.

    PubMed

    Hedley, Gordon J; Ward, Alexander J; Alekseev, Alexander; Howells, Calvyn T; Martins, Emiliano R; Serrano, Luis A; Cooke, Graeme; Ruseckas, Arvydas; Samuel, Ifor D W

    2013-01-01

    The morphology of bulk heterojunction organic photovoltaic cells controls many of the performance characteristics of devices. However, measuring this morphology is challenging because of the small length-scales and low contrast between organic materials. Here we use nanoscale photocurrent mapping, ultrafast fluorescence and exciton diffusion to observe the detailed morphology of a high-performance blend of PTB7:PC71BM. We show that optimized blends consist of elongated fullerene-rich and polymer-rich fibre-like domains, which are 10-50 nm wide and 200-400 nm long. These elongated domains provide a concentration gradient for directional charge diffusion that helps in the extraction of charge pairs with 80% efficiency. In contrast, blends with agglomerated fullerene domains show a much lower efficiency of charge extraction of ~45%, which is attributed to poor electron and hole transport. Our results show that the formation of narrow and elongated domains is desirable for efficient bulk heterojunction solar cells.

  15. Fabrication and characterization of organic single crystal and printed polymer transistors

    NASA Astrophysics Data System (ADS)

    Xia, Yu

    The key challenges in the development of organic electronics lie in the understanding of the charge transport physics and the realization of low cost device fabrication. Innovative studies on both aspects have been demonstrated in this thesis. On the fundamental side, first, charge transport and localization processes in various organic single crystal transistors have been investigated using a novel "air-gap"device geometry. Second, comparison of mobility - carrier density relation in polymer and single crystal transistors has been made by the utilization of different liquid gate dielectrics with extremely wide capacitance range, and fundamentally different charge transport mechanisms have been proposed. Third, direct measurement of the electrochemical potential at organic semiconductor/gate dielectric interfaces in electrolyte gated transistors has been achieved with the assistance of an embedded reference electrode. The correlation between the referenced turn-on voltages and the organic semiconductor ionization potentials has been discovered. Finally, an unusual negative differential transconductance behavior in electrolyte gated transistors upon inducing high gate carrier densities has been extensively investigated. On the application side, high performance polymer transistors and circuits were fabricated by a commercial aerosol jet printing technique. Printing not only saves the device manufacturing cost through its simple procedure, high throughput and low waste of materials, but also enables the fabrication of electronic devices over large area and on flexible substrates. All-printed transistors with exceptionally large transconductance of 10 mS/mm under 1 V of operating voltage have been realized with the application of specially designed printable high capacitance (>10 muF/cm2) ion gel as the gate dielectric material. Various device configurations and parameters have been investigated to further reduce the fabrication cost and improve the operating speed

  16. Investigations of the surface activation of thermoplastic polymers by atmospheric pressure plasma treatment with a stationary plasma jet

    NASA Astrophysics Data System (ADS)

    Moritzer, Elmar; Nordmeyer, Timo; Leister, Christian; Schmidt, Martin Andreas; Grishin, Artur; Knospe, Alexander

    2016-03-01

    The production of high-quality thermoplastic parts often requires an additional process step after the injection molding stage. This may be a coating, bonding process or a 2K-injection moulding process. A commonly used process to improve the bond strength is atmospheric pressure plasma treatment. A variety of applications are realized with the aid of CNC systems. Although they ensure excellent reproducibility, they make it difficult to implement inline applications. This paper therefore examines the possibility of surface treatment using a stationary plasma jet. However, before it is possible to integrate this technology into a production process, preliminary trials need to be carried out to establish which factors influence the process. Experimental tests were performed using a special test set-up, enabling geometric, plasma-specific parameters to be identified. These results can help with the practical integration of this technology into existing production processes.

  17. Organized living: formation mechanisms and functions of plasma membrane domains in yeast.

    PubMed

    Ziółkowska, Natasza E; Christiano, Romain; Walther, Tobias C

    2012-03-01

    Plasma membrane proteins and lipids organize into lateral domains of specific composition. Domain formation is achieved by a combination of lipid-lipid and lipid-protein interactions, membrane-binding protein scaffolds and protein fences. The resulting domains function in membrane protein turnover and homeostasis, as well as in cell signaling. We review the mechanisms generating plasma membrane domains and the functional consequences of this organization, focusing on recent findings from research on the yeast model system.

  18. Plasma-deposited fluorocarbon polymer films on titanium for preventing cell adhesion: a surface finishing for temporarily used orthopaedic implants

    NASA Astrophysics Data System (ADS)

    Finke, B.; Testrich, H.; Rebl, H.; Walschus, U.; Schlosser, M.; Zietz, C.; Staehlke, S.; Nebe, J. B.; Weltmann, K. D.; Meichsner, J.; Polak, M.

    2016-06-01

    The design of a titanium implant surface should ideally support its later application in clinical use. Temporarily used implants have to fulfil requirements different from permanent implants: they should ensure the mechanical stabilization of the bone stock but in trauma surgery they should not be integrated into the bone because they will be removed after fracture healing. Finishing of the implant surface by a plasma-fluorocarbon-polymer (PFP) coating is a possible approach for preventing cell adhesion of osteoblasts. Two different low pressure gas-discharge plasma processes, microwave (MW 2.45 GHz) and capacitively coupled radio frequency (RF 13.56 MHz) plasma, were applied for the deposition of the PFP film using a mixture of the precursor octafluoropropane (C3F8) and hydrogen (H2). The thin films were characterized by x-ray photoelectron spectroscopy, Fourier transform infrared reflection absorption spectroscopy, and water contact angle measurements. Cell culture experiments show that cell adhesion and spreading of MG-63 osteoblasts were clearly reduced or nonexistent on these surfaces, also after 24 h of storage in the cell culture medium. In vivo data demonstrated that the local inflammatory tissue response for the PFP films deposited in MW and RF plasma were comparable to uncoated controls.

  19. Water-Stable Metal-Organic Framework/Polymer Composites Compatible with Human Hepatocytes.

    PubMed

    Neufeld, Megan J; Ware, Brenton R; Lutzke, Alec; Khetani, Salman R; Reynolds, Melissa M

    2016-08-01

    Metal-organic frameworks (MOFs) have demonstrated promise in biomedical applications as vehicles for drug delivery, as well as for the ability of copper-based MOFs to generate nitric oxide (NO) from endogenous S-nitrosothiols (RSNOs). Because NO is a participant in biological processes where it exhibits anti-inflammatory, antibacterial, and antiplatelet activation properties, it has received significant attention for therapeutic purposes. Previous work has shown that the water-stable MOF H3[(Cu4Cl)3-(BTTri)8] (H3BTTri = 1,3,5-tris(1H-1,2,3-triazol-5-yl)benzene), or CuBTTri, produces NO from RSNOs and can be included within a polymeric matrix to form NO-generating materials. While such materials demonstrate potential, the possibility of MOF degradation leading to copper-related toxicity is a concern that must be addressed prior to adapting these materials for biomedical applications. Herein, we present the first cytotoxicity evaluation of an NO-generating CuBTTri/polymer composite material using 3T3-J2 murine embryonic fibroblasts and primary human hepatocytes (PHHs). CuBTTri/polymer films were prepared from plasticized poly(vinyl chloride) (PVC) and characterized via PXRD, ATR-FTIR, and SEM-EDX. Additionally, the ability of the CuBTTri/polymer films to enhance NO generation from S-nitroso-N-acetylpenicillamine (SNAP) was evaluated. Enhanced NO generation in the presence of the CuBTTri/polymer films was observed, with an average NO flux (0.90 ± 0.13 nmol cm(-2) min(-1)) within the range associated with antithrombogenic surfaces. The CuBTTri/polymer films were analyzed for stability in phosphate buffered saline (PBS) and cell culture media under physiological conditions for a 4 week duration. Cumulative copper release in both cell media (0.84 ± 0.21%) and PBS (0.18 ± 0.01%) accounted for less than 1% of theoretical copper present in the films. In vitro cell studies performed with 3T3-J2 fibroblasts and PHHs did not indicate significant toxicity, providing further

  20. The effect of branching in a semiconducting polymer on the efficiency of organic photovoltaic cells.

    PubMed

    Heintges, Gaël H L; van Franeker, Jacobus J; Wienk, Martijn M; Janssen, René A J

    2016-01-01

    The impact of branching in a diketopyrrolopyrrole polymer on the performance of polymer-fullerene photovoltaic cells is investigated. Compared to the linear polymer, the branched polymer affords a more finely dispersed fibrillar network in the photoactive layer and as a result a large enhancement of the photocurrent and power conversion efficiency.

  1. [An investigation of HAP/organic polymer composite coating prepared by electrochemical co-deposition technique (II) characterization of XRD, SEM and mechanic properties].

    PubMed

    Hu, Haobing; Lin, Changjian; Leng, Yang

    2003-06-01

    Electrodeposition hydroxyapatite(HAP) coatings of ceramics were studied by Nano Indent. The bonding force between the coating and metal substrate was distinctly increased. The experiments about XPS and SIMS showed that there is the act of organic polymer enriching at negative. It ensues that minor organic polymer is compounded to HAP coatings at molecular level and forms that HAP/Organic polymer compound coating.

  2. Chlorine-rich plasma polymer coating for the prevention of attachment of pathogenic fungal cells onto materials surfaces

    NASA Astrophysics Data System (ADS)

    Lamont-Friedrich, Stephanie J.; Michl, Thomas D.; Giles, Carla; Griesser, Hans J.; Coad, Bryan R.

    2016-07-01

    The attachment of pathogenic fungal cells onto materials surfaces, which is often followed by biofilm formation, causes adverse consequences in a wide range of areas. Here we have investigated the ability of thin film coatings from chlorinated molecules to deter fungal colonization of solid materials by contact killing of fungal cells reaching the surface of the coating. Coatings were deposited onto various substrate materials via plasma polymerization, which is a substrate-independent process widely used for industrial coating applications, using 1,1,2-trichloroethane as the process vapour. XPS surface analysis showed that the coatings were characterized by a highly chlorinated hydrocarbon polymer nature, with only a very small amount of oxygen incorporated. The activity of these coatings against human fungal pathogens was quantified using a recently developed, modified yeast assay and excellent antifungal activity was observed against Candida albicans and Candida glabrata. Plasma polymer surface coatings derived from chlorinated hydrocarbon molecules may therefore offer a promising solution to preventing yeast and mould biofilm formation on materials surfaces, for applications such as air conditioners, biomedical devices, food processing equipment, and others.

  3. Pharmacokinetic study of arctigenin in rat plasma and organ tissue by RP-HPLC method.

    PubMed

    He, Fan; Dou, De-Qiang; Hou, Qiang; Sun, Yu; Kang, Ting-Guo

    2013-01-01

    A high-performance liquid chromatography (HPLC) technique was developed for the determination of arctigenin in plasma and various organs of rats after the oral administration of 30, 50 and 70 mgkg(-1) of arctigenin to the Sprague-Dawley rats. Results showed that the validated HPLC method was simple, fast, reproducible and suitable to the determination of arctigenin in rat plasma and organ tissue and one-compartmental model with zero-order absorption process can well describe the changes of arctigenin concentration in the plasma. The concentration of compound was highest in the spleen, less in the liver and the least in the lung.

  4. Three-electrode direct current argon plasma: studies in discrete sample introduction, mathematical correction of drifted plasma data, and organic solvent introduction effects in the plasma

    SciTech Connect

    Boyko, W.J.

    1985-01-01

    This thesis investigates three areas of research with the three-electrode direct-current argon plasma(DCP). The first area examines discrete sample introduction into the DCP. Discrete sampling, well known for its sample conservation advantage, has been used with flame atomic absorption and inductively coupled plasma emission spectroscopies but no work has been published on using this sampling mode with the DCP. Discrete sample introduction is compared here to the standard continuous sampling mode. An unique sample drop generator is described and characterized. Results are given for a variety of system effects and used to explain the effect of sample drop size on emission intensity. The second area of research involves the use of mathematical correction techniques for removing the effect of plasma emission drift from analytical data. The introduction of hydrophobic samples into the DCP is the last area examined in this thesis. Organic matrices are routinely run on the DCP but they can be prone to little understood matrix interferences effects. A modified sample introduction chimney was designed that largely eliminated the carbon buildup encountered with the standard chimney permitting extensive studies using organic solvent with the plasma. It was found that the analytical emission zone of the plasma appears to be spatially tied to the plasma core.

  5. Characterization of an atmospheric pressure air plasma source for polymer surface modification

    NASA Astrophysics Data System (ADS)

    Yang, Shujun; Tang, Jiansheng

    2013-10-01

    An atmospheric pressure air plasma source was generated through dielectric barrier discharge (DBD). It was used to modify polyethyleneterephthalate (PET) surfaces with very high throughput. An equivalent circuit model was used to calculate the peak average electron density. The emission spectrum from the plasma was taken and the main peaks in the spectrum were identified. The ozone density in the down plasma region was estimated by Absorption Spectroscopy. NSF and ARC-ODU

  6. Experimental Studies of Self Organization with Electron Plasmas

    SciTech Connect

    Matthaeus, William H.

    2011-04-11

    During the period of this grant we had a very active research effort in our group on the topic of 2D electron plasmas, relaxation, 2D Navier Stokes turbulence, and related issues. The project also motivated other studies we carried out such as a study of 2D turbulence with two-species vorticity.

  7. A robust microfluidic device for the synthesis and crystal growth of organometallic polymers with highly organized structures.

    PubMed

    Liu, Xiao; Yi, Qiaolian; Han, Yongzhen; Liang, Zhenning; Shen, Chaohua; Zhou, Zhengyang; Sun, Jun-Liang; Li, Yizhi; Du, Wenbin; Cao, Rui

    2015-02-01

    A simple and robust microfluidic device was developed to synthesize organometallic polymers with highly organized structures. The device is compatible with organic solvents. Reactants are loaded into pairs of reservoirs connected by a 15 cm long microchannel prefilled with solvents, thus allowing long-term counter diffusion for self-assembly of organometallic polymers. The process can be monitored, and the resulting crystalline polymers are harvested without damage. The device was used to synthesize three insoluble silver acetylides as single crystals of X-ray diffraction quality. Importantly, for the first time, the single-crystal structure of silver phenylacetylide was determined. The reported approach may have wide applications, such as crystallization of membrane proteins, synthesis and crystal growth of organic, inorganic, and polymeric coordination compounds, whose single crystals cannot be obtained using traditional methods.

  8. Thermal compression chip interconnection using organic solderability preservative etched substrate by plasma processing.

    PubMed

    Cho, Sung-Won; Choi, JoonYoung; Chung, Chin-Wook

    2014-12-01

    The solderability of copper organic solderbility preservative (CuOSP) finished substrate was enhanced by the plasma etching. To improve the solderability of TC interconnection with the CuOSP finished substrate, the plasma etching process is used. An Oxygen-Hydrogen plasma treatment process is performed to remove OSP material. To prevent the oxidation by oxygen plasma treatment, hydrogen reducing process is also performed before TC interconnection process. The thickness of OSP material after plasma etching is measured by optical reflection method and the component analysis by Auger Electron Spectroscopy is performed. From the lowered thickness, the bonding force of TC interconnection after OSP etching process is lowered. Also the electrical open/short test was performed after assembling the completed semiconductor packaging. The improved yield due to the plasma etching process is achieved.

  9. Quantitative extraction of organic tracer compounds from ambient particulate matter collected on polymer substrates.

    PubMed

    Sun, Qinyue; Alexandrova, Olga A; Herckes, Pierre; Allen, Jonathan O

    2009-05-15

    Organic compounds in ambient particulate matter (PM) samples are used as tracers for PM source apportionment. These PM samples are collected using high volume samplers; one such sampler is an impactor in which polyurethane foam (PUF) and polypropylene foam (PPF) are used as the substrates. The polymer substrates have the advantage of limiting particle bounce artifacts during sampling; however these substrates may contain background organic additives. A protocol of two extractions with isopropanol followed by three extractions with dichloromethane (DCM) was developed for both substrate precleaning and analyte extraction. Some residual organic contaminants were present after precleaning; expressed as concentrations in a 24-h ambient PM sample, the residual amounts were 1 microg m(-3) for plasticizers and antioxidants, and 10 ng m(-3) for n-alkanes with carbon number lower than 26. The quantification limit for all other organic tracer compounds was approximately 0.1 ng m(-3) in a 24-h ambient PM sample. Recovery experiments were done using NIST Standard Reference Material (SRM) Urban Dust (1649a); the average recoveries for polycyclic aromatic hydrocarbons (PAHs) from PPF and PUF substrates were 117+/-8% and 107+/-11%, respectively. Replicate extractions were also done using the ambient samples collected in Nogales, Arizona. The relative differences between repeat analyses were less than 10% for 47 organic tracer compounds quantified. After the first extraction of ambient samples, less than 7% of organic tracer compounds remained in the extracted substrates. This method can be used to quantify a suite of semi- and non-polar organic tracer compounds suitable for source apportionment studies in 24-h ambient PM samples.

  10. Fabrication of Ruthenium Nanoparticles in Porous Organic Polymers: Towards Advanced Heterogeneous Catalytic Nanoreactors.

    PubMed

    Mondal, John; Kundu, Sudipta K; Hung Ng, Wilson Kwok; Singuru, Ramana; Borah, Parijat; Hirao, Hajime; Zhao, Yanli; Bhaumik, Asim

    2015-12-21

    A novel strategy has been adopted for the construction of a copolymer of benzene-benzylamine-1 (BBA-1), which is a porous organic polymer (POP) with a high BET surface area, through Friedel-Crafts alkylation of benzylamine and benzene by using formaldehyde dimethyl acetal as a cross-linker and anhydrous FeCl3 as a promoter. Ruthenium nanoparticles (Ru NPs) were successfully distributed in the interior cavities of polymers through NaBH4, ethylene glycol, and hydrothermal reduction routes, which delivered Ru-A, Ru-B, and Ru-C materials, respectively, and avoided aggregation of metal NPs. Homogeneous dispersion, the nanoconfinement effect of the polymer, and the oxidation state of Ru NPs were verified by employing TEM, energy-dispersive X-ray spectroscopy mapping, cross polarization magic-angle spinning (13)C NMR spectroscopy, and X-ray photoelectron spectroscopy analytical tools. These three new Ru-based POP materials exhibited excellent catalytic performance in the hydrogenation of nitroarenes at RT (with a reaction time of only ≈ 30 min), with high conversion, selectivity, stability, and recyclability for several catalytic cycles, compared with other traditional materials, such as Ru@C, Ru@SiO2, and Ru@TiO2, but no clear agglomeration or loss of catalytic activity was observed. The high catalytic performance of the ruthenium-based POP materials is due to the synergetic effect of nanoconfinement and electron donation offered by the 3D POP network. DFT calculations showed that hydrogenation of nitrobenzene over the Ru (0001) catalyst surface through a direct reaction pathway is more favorable than that through an indirect reaction pathway.

  11. Fabrication of Ruthenium Nanoparticles in Porous Organic Polymers: Towards Advanced Heterogeneous Catalytic Nanoreactors.

    PubMed

    Mondal, John; Kundu, Sudipta K; Hung Ng, Wilson Kwok; Singuru, Ramana; Borah, Parijat; Hirao, Hajime; Zhao, Yanli; Bhaumik, Asim

    2015-12-21

    A novel strategy has been adopted for the construction of a copolymer of benzene-benzylamine-1 (BBA-1), which is a porous organic polymer (POP) with a high BET surface area, through Friedel-Crafts alkylation of benzylamine and benzene by using formaldehyde dimethyl acetal as a cross-linker and anhydrous FeCl3 as a promoter. Ruthenium nanoparticles (Ru NPs) were successfully distributed in the interior cavities of polymers through NaBH4, ethylene glycol, and hydrothermal reduction routes, which delivered Ru-A, Ru-B, and Ru-C materials, respectively, and avoided aggregation of metal NPs. Homogeneous dispersion, the nanoconfinement effect of the polymer, and the oxidation state of Ru NPs were verified by employing TEM, energy-dispersive X-ray spectroscopy mapping, cross polarization magic-angle spinning (13)C NMR spectroscopy, and X-ray photoelectron spectroscopy analytical tools. These three new Ru-based POP materials exhibited excellent catalytic performance in the hydrogenation of nitroarenes at RT (with a reaction time of only ≈ 30 min), with high conversion, selectivity, stability, and recyclability for several catalytic cycles, compared with other traditional materials, such as Ru@C, Ru@SiO2, and Ru@TiO2, but no clear agglomeration or loss of catalytic activity was observed. The high catalytic performance of the ruthenium-based POP materials is due to the synergetic effect of nanoconfinement and electron donation offered by the 3D POP network. DFT calculations showed that hydrogenation of nitrobenzene over the Ru (0001) catalyst surface through a direct reaction pathway is more favorable than that through an indirect reaction pathway. PMID:26572500

  12. Solution processed organic light-emitting diodes using the plasma cross-linking technology

    NASA Astrophysics Data System (ADS)

    He, Kongduo; Liu, Yang; Gong, Junyi; Zeng, Pan; Kong, Xun; Yang, Xilu; Yang, Cheng; Yu, Yan; Liang, Rongqing; Ou, Qiongrong

    2016-09-01

    Solution processed multilayer organic light-emitting diodes (OLEDs) present challenges, especially regarding dissolution of the first layer during deposition of a second layer. In this work, we first demonstrated a plasma cross-linking technology to produce a solution processed OLED. The surfaces of organic films can be cross-linked after mixed acetylene and Ar plasma treatment for several tens of seconds and resist corrosion of organic solvent. The film thickness and surface morphology of emissive layers (EMLs) with plasma treatment and subsequently spin-rinsed with chlorobenzene are nearly unchanged. The solution processed triple-layer OLED is successfully fabricated and the current efficiency increases 50% than that of the double-layer OLED. Fluorescent characteristics of EMLs are also observed to investigate factors influencing the efficiency of the triple-layer OLED. Plasma cross-linking technology may open up a new pathway towards fabrication of all-solution processed multilayer OLEDs and other soft electronic devices.

  13. The Role of Fullerene Mixing Behavior in the Performance of Organic Rhotovoltaics: PCBM in Low-Bandgap Polymers.

    SciTech Connect

    Chen, Huipeng; Peet, Jeff; Hu, Sheng; Azoulay, Jason; Bazan, Guillermo; Dadmun, Mark D

    2014-01-01

    This manuscript reports the mixing behavior, interdiffusion, and depth profile of 1-[3-(methoxycarbonyl)propyl]-1-phenyl-[6,6]C 61 (PCBM):low-bandgap (LBG) polymer thin fi lms that are formed by thermally annealing initial bilayers. The extent of mixing of PCBM is higher in polymers that include the 2,1,3-benzothiadiazole (BT) unit than in polymers that incorporate the 2,1,3-benzooxadiazole (BO) unit. This difference is ascribed to the enhanced mixing behavior of PCBM with the benzothiadiazole functionality than with benzooxadiazole functionality, which is attributed to preferred intermolecular interactions. The increased polymer/fullerene mixing is found to be crucial for optimal device performance. A decrease of polymer/fullerene mixing reduces the donor/acceptor interface, which lowers the probability of exciton dissociation and charge generation. Moreover, low PCBM mixing provides limited pathways for electron transport out of a miscible region, due to long distances between adjacent PCBM in such a miscible phase. This inhibits electron transport and increases the recombination of free charge carriers, resulting in a decrease in short circuit current and device performance. These results further exemplify the importance of the thermodynamic mixing behavior of the polymer:fullerene pair in designing next-generation conjugated polymers for organic photovoltaic (OPV) applications, as this controls the fi nal morphology of the OPV active layer.

  14. Bioadhesive control of plasma proteins and blood cells from umbilical cord blood onto the interface grafted with zwitterionic polymer brushes.

    PubMed

    Chang, Yu; Chang, Yung; Higuchi, Akon; Shih, Yu-Ju; Li, Pei-Tsz; Chen, Wen-Yih; Tsai, Eing-Mei; Hsiue, Ging-Ho

    2012-03-01

    In this work, bioadhesive behavior of plasma proteins and blood cells from umbilical cord blood (UCB) onto zwitterionic poly(sulfobetaine methacrylate) (polySBMA) polymer brushes was studied. The surface coverage of polySBMA brushes on a hydrophobic polystyrene (PS) well plate with surface grafting weights ranging from 0.02 mg/cm(2) to 0.69 mg/cm(2) can be effectively controlled using the ozone pretreatment and thermal-induced radical graft-polymerization. The chemical composition, grafting structure, surface hydrophilicity, and hydration capability of prepared polySBMA brushes were determined to illustrate the correlations between grafting properties and blood compatibility of zwitterionic-grafted surfaces in contact with human UCB. The protein adsorption of fibrinogen in single-protein solutions and at complex medium of 100% UCB plasma onto different polySBMA brushes with different grafting coverage was measured by enzyme-linked immunosorbent assay (ELISA) with monoclonal antibodies. The grafting density of the zwitterionic brushes greatly affects the PS surface, thus controlling the adsorption of fibrinogen, the adhesion of platelets, and the preservation of hematopoietic stem and progenitor cells (HSPCs) in UCB. The results showed that PS surfaces grafted with polySBMA brushes possess controllable hydration properties through the binding of water molecules, regulating the bioadhesive and bioinert characteristics of plasma proteins and blood platelets in UCB. Interestingly, it was found that the polySBMA brushes with an optimized grafting weight of approximately 0.1 mg/cm(2) at physiologic temperatures show significant hydrated chain flexibility and balanced hydrophilicity to provide the best preservation capacity for HSPCs stored in 100% UCB solution for 2 weeks. This work suggests that, through controlling grafting structures, the hemocompatible nature of grafted zwitterionic polymer brushes makes them well suited to the molecular design of regulated

  15. Electroanalytical measurements without electrolytes: conducting polymers as probes for redox titration in non-conductive organic media.

    PubMed

    Lange, Ulrich; Mirsky, Vladimir M

    2012-09-26

    Electroanalytical methods have been applied only in conducting media. An application of conducting polymers allows to overcome this limitation. If such material is in electrochemical equilibrium with dissolved redox active species, its electrical conductivity depends on the redox potential of these species. Therefore, conductometric measurements with conducting polymers can provide about the same information as classical redox electrodes. The approach was applied for redox titration. Equivalent points obtained by this titration in aqueous and organic electrolytes were identical. Then the approach was applied for determination of bromine number by redox titration in non-conducting organic phase.

  16. Effects of H{sub 2} plasma treatment on the electrical properties of titanium-doped indium oxide films prepared by polymer-assisted deposition

    SciTech Connect

    Hwang, Joo-Sang; Lee, Ji-Myon; Vishwanath, Sujaya Kumar; Kim, Jihoon

    2015-07-15

    The effects of hydrogen (H{sub 2}) plasma on the optical and electrical properties of titanium-doped InO (TIO) grown on glass substrates using polymer-assisted deposition are reported. Samples were exposed to H{sub 2} plasma formed by inductively coupled plasma (ICP). After plasma treatment at a power of 100 W, the sheet resistance of the TIO films decreased from 11 000 to 285 Ω/sq. Additionally, the Hall mobility and sheet carrier concentration of the films increased as the ICP source power was increased to 100 W, without affecting the optical transmittance of the films, due to the removal of the polymer residues and the formation of oxygen vacancies.

  17. Nontemplate-driven polymers: clues to a minimal form of organization closure at the early stages of living systems.

    PubMed

    Freire, Miguel Ángel

    2015-06-01

    The emergence of the first polymers played an essential role in the transition from the physicochemical to the biological domain, a perception that embodied many different world paradigms relying on only one primal polymer. However, biological complexity would have appeared with an increasing set of associated chemistries and molecular interactions of many different macromolecules. In agreement with this notion, here, the purpose is to focus specific attention on current knowledge of modern biochemistry of a set of widespread polymers likely present in the Last Universal Common Ancestor synthesized by nontemplate-driven reactions with references to their abiotic synthesis. The proposed overview describes the manner in which these polymers could have organized around two polymerization reaction cycles and integrated into a minimal organizational closure at the early stages of living systems, independently of template replication processes. This hypothesis could provide an alternative conceptual framework to evaluate a plausible scenario addressing the transition from nonliving to protocellular systems.

  18. Nontemplate-driven polymers: clues to a minimal form of organization closure at the early stages of living systems.

    PubMed

    Freire, Miguel Ángel

    2015-06-01

    The emergence of the first polymers played an essential role in the transition from the physicochemical to the biological domain, a perception that embodied many different world paradigms relying on only one primal polymer. However, biological complexity would have appeared with an increasing set of associated chemistries and molecular interactions of many different macromolecules. In agreement with this notion, here, the purpose is to focus specific attention on current knowledge of modern biochemistry of a set of widespread polymers likely present in the Last Universal Common Ancestor synthesized by nontemplate-driven reactions with references to their abiotic synthesis. The proposed overview describes the manner in which these polymers could have organized around two polymerization reaction cycles and integrated into a minimal organizational closure at the early stages of living systems, independently of template replication processes. This hypothesis could provide an alternative conceptual framework to evaluate a plausible scenario addressing the transition from nonliving to protocellular systems. PMID:25916275

  19. Metal-organic framework nanosheets in polymer composite materials for gas separation

    NASA Astrophysics Data System (ADS)

    Rodenas, Tania; Luz, Ignacio; Prieto, Gonzalo; Seoane, Beatriz; Miro, Hozanna; Corma, Avelino; Kapteijn, Freek; Llabrés I Xamena, Francesc X.; Gascon, Jorge

    2015-01-01

    Composites incorporating two-dimensional nanostructures within polymeric matrices have potential as functional components for several technologies, including gas separation. Prospectively, employing metal-organic frameworks (MOFs) as versatile nanofillers would notably broaden the scope of functionalities. However, synthesizing MOFs in the form of freestanding nanosheets has proved challenging. We present a bottom-up synthesis strategy for dispersible copper 1,4-benzenedicarboxylate MOF lamellae of micrometre lateral dimensions and nanometre thickness. Incorporating MOF nanosheets into polymer matrices endows the resultant composites with outstanding CO2 separation performance from CO2/CH4 gas mixtures, together with an unusual and highly desired increase in the separation selectivity with pressure. As revealed by tomographic focused ion beam scanning electron microscopy, the unique separation behaviour stems from a superior occupation of the membrane cross-section by the MOF nanosheets as compared with isotropic crystals, which improves the efficiency of molecular discrimination and eliminates unselective permeation pathways. This approach opens the door to ultrathin MOF-polymer composites for various applications.

  20. Knitting aromatic polymers for efficient solid-phase microextraction of trace organic pollutants.

    PubMed

    Liu, Shuqin; Hu, Qingkun; Zheng, Juan; Xie, Lijun; Wei, Songbo; Jiang, Ruifen; Zhu, Fang; Liu, Yuan; Ouyang, Gangfeng

    2016-06-10

    A series of knitting aromatic polymers (KAPs) were successfully synthesized using a simple one-step Friedel-Crafts alkylation of aromatic monomers and were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Then, as-synthesized KAPs with large surface areas, unique pore structures and high thermal stability were prepared as solid-phase microextraction (SPME) coatings that exhibited good extraction abilities for a series of benzene compounds (i.e., benzene, toluene, ethylbenzene and m-xylene, which are referred to as BTEX) and polycyclic aromatic hydrocarbons (PAHs). Under the optimized conditions, the methodologies established for the determination of BTEX and PAHs using the KAPs-triPB and KAPs-B coatings, respectively, possessed wide linear ranges, low limits of detection (LODs, 0.10-1.13ngL(-1) for BTEX and 0.05-0.49ngL(-1) for PAHs) and good reproducibility. Finally, the proposed methods were successfully applied to the determination of BTEX and PAHs in environmental water samples, and satisfactory recoveries (93.6-124.2% for BTEX and 77.2-113.3% for PAHs) were achieved. This study provides a benchmark for exploiting novel microporous organic polymers (MOPs) for SPME applications. PMID:27155913

  1. Knitting aromatic polymers for efficient solid-phase microextraction of trace organic pollutants.

    PubMed

    Liu, Shuqin; Hu, Qingkun; Zheng, Juan; Xie, Lijun; Wei, Songbo; Jiang, Ruifen; Zhu, Fang; Liu, Yuan; Ouyang, Gangfeng

    2016-06-10

    A series of knitting aromatic polymers (KAPs) were successfully synthesized using a simple one-step Friedel-Crafts alkylation of aromatic monomers and were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Then, as-synthesized KAPs with large surface areas, unique pore structures and high thermal stability were prepared as solid-phase microextraction (SPME) coatings that exhibited good extraction abilities for a series of benzene compounds (i.e., benzene, toluene, ethylbenzene and m-xylene, which are referred to as BTEX) and polycyclic aromatic hydrocarbons (PAHs). Under the optimized conditions, the methodologies established for the determination of BTEX and PAHs using the KAPs-triPB and KAPs-B coatings, respectively, possessed wide linear ranges, low limits of detection (LODs, 0.10-1.13ngL(-1) for BTEX and 0.05-0.49ngL(-1) for PAHs) and good reproducibility. Finally, the proposed methods were successfully applied to the determination of BTEX and PAHs in environmental water samples, and satisfactory recoveries (93.6-124.2% for BTEX and 77.2-113.3% for PAHs) were achieved. This study provides a benchmark for exploiting novel microporous organic polymers (MOPs) for SPME applications.

  2. Spectroscopic Evidence of Anthropogenic Compounds Extraction from Polymers by Fluorescent Dissolved Organic Matter in Natural Water

    NASA Astrophysics Data System (ADS)

    Miranda, M.; Trojzuck, A.; Voss, D.; Gassmann, S.; Zielinski, O.

    2016-04-01

    FDOM is one of the most important carriers of anthropogenic compounds in natural waters. It can combine with environmental contaminants and polymers to form diverse chemical structures. To this end, here a microfluidic chip was designed for the analysis of these changes in fluorescent dissolved organic matter (FDOM) fingerprints due to thermal treatment and varying time intervals of exposure. Excitation Emission Matrix Spectroscopy (EEMS) approach was utilized to detect and identify the inherent compounds in sampled FDOM. Strong direct correlations were founded, Spearman rank correlation values (ρ = 0.85 at α = 0.1, n = 4) and linear correlation R2 = 0.8359 were noted between thermal treatment pattern 2 and fluorescence intensity of samples. Materials, acrylic based glue and cyclic olefin copolymer (COC) polymer, used to design the microfluidic sensor were determined to possess unique spectral features in the ultraviolet to green spectrum using EEMS. The study therefore provides an insight on methods to identify contaminants in natural waters. This underlines the potential of optical sensors providing measurements at fast intervals, enabling environmental monitoring.

  3. Metal-organic framework nanosheets in polymer composite materials for gas separation

    PubMed Central

    Seoane, Beatriz; Miro, Hozanna; Corma, Avelino; Kapteijn, Freek; Llabrés i Xamena, Francesc X.; Gascon, Jorge

    2014-01-01

    Composites incorporating two-dimensional nanostructures within polymeric matrices hold potential as functional components for several technologies, including gas separation. Prospectively, employing metal-organic-frameworks (MOFs) as versatile nanofillers would notably broaden the scope of functionalities. However, synthesizing MOFs in the form of free standing nanosheets has proven challenging. We present a bottom-up synthesis strategy for dispersible copper 1,4-benzenedicarboxylate MOF lamellae of micrometer lateral dimensions and nanometer thickness. Incorporating MOF nanosheets into polymer matrices endows the resultant composites with outstanding CO2 separation performance from CO2/CH4 gas mixtures, together with an unusual and highly desired increment in the separation selectivity with pressure. As revealed by tomographic focused-ion-beam scanning-electron-microscopy, the unique separation behaviour stems from a superior occupation of the membrane cross-section by the MOF nanosheets as compared to isotropic crystals, which improves the efficiency of molecular discrimination and eliminates unselective permeation pathways. This approach opens the door to ultrathin MOF-polymer composites for various applications. PMID:25362353

  4. The Integration and Applications of Organic Thin Film Transistors and Ferroelectric Polymers

    NASA Astrophysics Data System (ADS)

    Hsu, Yu-Jen

    Organic thin film transistors and ferroelectric polymer (polyvinylidene difluoride) sheet material are integrated to form various sensors for stress/strain, acoustic wave, and Infrared (heat) sensing applications. Different from silicon-based transistors, organic thin film transistors can be fabricated and processed in room-temperature and integrated with a variety of substrates. On the other hand, polyvinylidene difluoride (PVDF) exhibits ferroelectric properties that are highly useful for sensor applications. The wide frequency bandwidth (0.001 Hz to 10 GHz), vast dynamic range (100n to 10M psi), and high elastic compliance (up to 3 percent) make PVDF a more suitable candidate over ceramic piezoelectric materials for thin and flexible sensor applications. However, the low Curie temperature may have impeded its integration with silicon technology. Organic thin film transistors, however, do not have the limitation of processing temperature, hence can serve as transimpedance amplifiers to convert the charge signal generated by PVDF into current signal that are more measurable and less affected by any downstream parasitics. Piezoelectric sensors are useful for a range of applications, but passive arrays suffer from crosstalk and signal attenuation which have complicated the development of array-based PVDF sensors. We have used organic field effect transistors, which are compatible with the low Curie temperature of a flexible piezoelectric polymer,PVDF, to monolithically fabricate transimpedance amplifiers directly on the sensor surface and convert the piezoelectric charge signal into a current signal which can be detected even in the presence of parasitic capacitances. The device couples the voltage generated by the PVDF film under strain into the gate of the organic thin film transistors (OFET) using an arrangement that allows the full piezoelectric voltage to couple to the channel, while also increasing the charge retention time. A bipolar detector is created by

  5. Organic-Inorganic Nanocomposites via Placing Monodisperse Ferroelectric Nanocrystals in Direct and Permanent Contact with Ferroelectric Polymers.

    PubMed

    Jiang, Beibei; Pang, Xinchang; Li, Bo; Lin, Zhiqun

    2015-09-16

    Organic-inorganic nanocomposites composed of polymers and nanoparticles offer a vast design space of potential material properties, depending heavily on the properties of these two constituents and their spatial arrangement. The ability to place polymers in direct contact with functional nanoparticles via strong bonding, that is, stable chemical interaction without the dissociation of surface capping polymers, provides a means of preventing nanoparticles from aggregation and increasing their dispersibility in nanocomposites, and promises opportunities to explore new properties and construction of miniaturized devices. However, this is still a challenging issue and has not yet been largely explored. Here, we report an unconventional strategy to create in situ organic-inorganic nanocomposites comprising monodisperse ferroelectric nanoparticles directly and permanently tethered with ferroelectric polymers by capitalizing on rationally designed amphiphilic star-like diblock copolymer as nanoreactors. The diameter of ferroelectric nanoparticles and the chain length of ferroelectric polymers can be precisely tuned. The dielectric and ferroelectric properties of nanocomposites containing different sizes of ferroelectric nanoparticles were scrutinized. Such bottom-up crafting of intimate organic-inorganic nanocomposites offers new levels of tailorability to nanostructured materials and promises new opportunities for achieving exquisite control over the surface chemistry and properties of nanocomposites with engineered functionality for diverse applications in energy conversion and storage, catalysis, electronics, nanotechnology, and biotechnology.

  6. 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.

  7. Molecular Design of Semiconducting Polymers for High-Performance Organic Electrochemical Transistors

    PubMed Central

    2016-01-01

    The organic electrochemical transistor (OECT), capable of transducing small ionic fluxes into electronic signals in an aqueous environment, is an ideal device to utilize in bioelectronic applications. Currently, most OECTs are fabricated with commercially available conducting poly(3,4-ethylenedioxythiophene) (PEDOT)-based suspensions and are therefore operated in depletion mode. Here, we present a series of semiconducting polymers designed to elucidate important structure–property guidelines required for accumulation mode OECT operation. We discuss key aspects relating to OECT performance such as ion and hole transport, electrochromic properties, operational voltage, and stability. The demonstration of our molecular design strategy is the fabrication of accumulation mode OECTs that clearly outperform state-of-the-art PEDOT-based devices, and show stability under aqueous operation without the need for formulation additives and cross-linkers. PMID:27444189

  8. Molecular Design of Semiconducting Polymers for High-Performance Organic Electrochemical Transistors.

    PubMed

    Nielsen, Christian B; Giovannitti, Alexander; Sbircea, Dan-Tiberiu; Bandiello, Enrico; Niazi, Muhammad R; Hanifi, David A; Sessolo, Michele; Amassian, Aram; Malliaras, George G; Rivnay, Jonathan; McCulloch, Iain

    2016-08-17

    The organic electrochemical transistor (OECT), capable of transducing small ionic fluxes into electronic signals in an aqueous environment, is an ideal device to utilize in bioelectronic applications. Currently, most OECTs are fabricated with commercially available conducting poly(3,4-ethylenedioxythiophene) (PEDOT)-based suspensions and are therefore operated in depletion mode. Here, we present a series of semiconducting polymers designed to elucidate important structure-property guidelines required for accumulation mode OECT operation. We discuss key aspects relating to OECT performance such as ion and hole transport, electrochromic properties, operational voltage, and stability. The demonstration of our molecular design strategy is the fabrication of accumulation mode OECTs that clearly outperform state-of-the-art PEDOT-based devices, and show stability under aqueous operation without the need for formulation additives and cross-linkers. PMID:27444189

  9. Preparation of dielectrics HR mirrors from colloidal oxide suspensions containing organic polymer binders

    SciTech Connect

    Thomas, I.M.

    1994-07-19

    Colloidal suspensions of oxides have been used to prepare dielectric HR (high reflective) mirrors, specifically for high power fusion case applications, on substrates up to 38 cm square using a meniscus coater. These coatings consist of porous quarterwave layers of alternating high and low refractive index oxides. Silica was used as the low index oxide and AlOOH, ZrO{sub 2}, or HfO{sub 2} as the high index material. Coatings were weak because of low particle-to-particle adhesion. Use of organic polymer binders in the high index component was found to increase strength, thereby improving the laser damage threshold and also reducing the number of layers required for 99% reflection due to increased refractive index.

  10. Ferrimagnetism and metal—insulator transition in an organic polymer chain

    NASA Astrophysics Data System (ADS)

    Ding, Lin-Jie; Zhong, Yuan; Fan, Shuai-Wei

    2014-02-01

    The ferrimagnetism and quantum phase transition of a bipartite lozenge periodic Anderson-like organic polymer, in which the localized f electrons hybridize with the odd site conduction orbitals, are investigated by means of Green's function theory. The ground state turns out to be gapless ferrimagnetism. At a finite temperature, the ferrimagnetic-to-paramagnetic phase transition takes place. The Kondo screenings and Ruderman—Kittel—Kasuya—Yosida (RKKY) interaction can reduce and increase the transition temperature, respectively. Two Kondo screenings compete with each other, giving rise to the localized f electron spin screened antiferromagnetically. Accordingly, in a magnetic field, all spins are aligned along the chain easily, which is associated with metal—insulator transition. Furthermore, in a temperature-field plane, we reveal the gapless and spin polarized phases, which are characterized by susceptibility and specific heat, and whose behaviours are determined by the competition between the up-spin and down-spin hole excitations.

  11. Predicting the ageing and the long-term durability of organic polymer solar cells

    NASA Astrophysics Data System (ADS)

    Gardette, Jean-Luc; Rivaton, Agnès; Thérias, Sandrine; Chambon, Sylvain; Manceau, Matthieu; Gaume, Julien

    2010-06-01

    Organic solar cells based on conductive polymers exhibit a unique combination of properties which include low cost, flexibility and large surface processability. Organic photovoltaic could then prevail for some applications alongside silicon, such as nomad or indoor. To achieve this objective, the sustainability of the initial properties in conditions of use of the cell is required, since it could be a lock to the emergence of these devices in the market. The polymers used in solar cells are indeed known to exhibit low resistance to environmental constraints, in particular to the combined action of sunlight, oxygen and water. We present recent results on both the accelerated artificial and the natural outdoors ageing of MDMO-PPV (Poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-Phenylenevinylene) and P3HT/PCBM blends poly(3-hexylthiophene) (P3HT) (methano-fullerene[6,6]-phenyl C61-butyric acid methyl ester) ([60] PCBM). The influence of various parameters such as the temperature and the presence of oxygen were studied. The modifications of the chemical structure of both the components of the blend were monitored by spectroscopic analysis (infrared, UV-visible), the morphology of the blends was analysed by AFM and XRD and the photovoltaic performances all along the exposure were recorded. Two important results have been pointed out: on one hand, the Achilles heel of the chemical structure of MDMO-PPV and P3HT under the impact of light has been evidenced. On the other hand, it has been shown that P3HT:PCBM blends are much more stable than MDMO:PCBM blends whatever the conditions of ageing are. Results show that a convenient encapsulation can ensure a promising lifetime of P3HT/PCBM blends in real conditions of use. This work also focuses on this last point and proposes to study and try to understand the behavior of the materials used in the active layer when submitted to photoaging and thermal aging in the absence of oxygen. To fulfil very good encapsulation, glass

  12. Molecular Design of Semiconducting Polymers for High-Performance Organic Electrochemical Transistors.

    PubMed

    Nielsen, Christian B; Giovannitti, Alexander; Sbircea, Dan-Tiberiu; Bandiello, Enrico; Niazi, Muhammad R; Hanifi, David A; Sessolo, Michele; Amassian, Aram; Malliaras, George G; Rivnay, Jonathan; McCulloch, Iain

    2016-08-17

    The organic electrochemical transistor (OECT), capable of transducing small ionic fluxes into electronic signals in an aqueous environment, is an ideal device to utilize in bioelectronic applications. Currently, most OECTs are fabricated with commercially available conducting poly(3,4-ethylenedioxythiophene) (PEDOT)-based suspensions and are therefore operated in depletion mode. Here, we present a series of semiconducting polymers designed to elucidate important structure-property guidelines required for accumulation mode OECT operation. We discuss key aspects relating to OECT performance such as ion and hole transport, electrochromic properties, operational voltage, and stability. The demonstration of our molecular design strategy is the fabrication of accumulation mode OECTs that clearly outperform state-of-the-art PEDOT-based devices, and show stability under aqueous operation without the need for formulation additives and cross-linkers.

  13. Discernment of Possible Organic Magnetic Field Effect Mechanisms Using Polymer Light-Emitting Electrochemical Cells

    NASA Astrophysics Data System (ADS)

    Geng, R.; Subedi, R. C.; Liang, S.; Nguyen, T. D.

    2014-07-01

    We report studies of magnetic field effect (MFE) in polymer light-emitting electrochemical cells (PLEC) using the "super-yellow" poly-(phenylene vynilene) (SY-PPV) polymer in vertical and planar device configurations. The purpose is to discern the existing MFE mechanisms in organic light emitting diodes (OLEDs) where the current and electroluminescence are strongly modulated by a small applied magnetic field. In particular, we investigate the mutual relationship between magneto-conductance (MC) and magneto-electroluminescence (MEL) by studying the role of polaron density dissociated from polaron pairs (PP) on these magnetic responses. In general, the dissociated polaron density is determined by the PP dissociation rate and the PP density. For the planar PLEC, which possesses a small dissociation rate, we observe small and negative MC at all applied voltages regardless of the emission intensity, while MEL becomes positive when electroluminescence quantum efficiency increases. The MC has a much narrower width than the MEL, indicating that the MC and MEL do not share a common origin. However, MC reverses and has the same width as MEL when the device is exposed to a threshold laser power. For the vertical PLEC, characterized by a large dissociation rate, MC and MEL are positive and have the same width. We discuss the results using the existing MFE mechanism in OLEDs. We show that the PP model can explain the positive MEL and MC, while the negative MC can be explained by the bipolaron model. Finally, we present a possibility to complete an all-organic PLEC magnetic sensor by using an inkjet printer.

  14. Spray deposited PTB7:PC71BM organic polymer solar cells for efficient power generation

    NASA Astrophysics Data System (ADS)

    Ochiai, Shizuyasu; Kumar, Palanisamy; Santhakumar, Kannappan; Saitoh, Leona; Kojima, Kenzo; Shin, Paik-Kyun

    2012-09-01

    Organic solar cell (OSC) materials have recently gained rich attention due to capable of efficient power conversion, cost-effective, mechanically flexible and light weight solar cells. At the same time further materials developments for high performance will be necessary for commercial production of organic photovoltaics. The increase of efficiency has resulted from the low band gab materials, combination of polymer: fullerene and presence of blend micro structure. In this regard, the authors have achieved an efficient polymer solar cells based on 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(PTB7) and [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) as donor and acceptor respectively. The photocurrent active layers were fabricated by spray coating technique which enables large area, low cost solar cells. A systematic analysis of PTB7:PC71BM devices carried out with TiOx electron transport layer, Chlorobenzene (CB) and 1,8 Diiodooctane (DIO) solvents. Optical and surface characterization analysis carried out by UV-visible and AFM techniques respectively. From the J-V characteristics, the device prepared with CB+DIO mixture solvents and TiOx layer exhibits the best power conversion efficiency of 4.90%. It shows the device efficiency is one order of magnitude higher compared to that achieved with a TiOx electron transport layer and without DIO solvent. The obtained results shows that DIO cosolvent induced changes in active layer morphology down to nano scale range and the TiOx layer decrease the resistance between the active layer and electrode material.

  15. Physics of interplanetary dust capture via impact into organic polymer foams

    NASA Technical Reports Server (NTRS)

    Anderson, William W.; Ahrens, Thomas J.

    1994-01-01

    The physics of hypervelocity impacts into foams is of interest because of the possible application to interplanetary dust particle (IDP) capture by spacecraft. We present a model for the phenomena occurring in such impacts into low-density organic polymer foams. Particles smaller than foam cells behave as if the foam is a series of solid slabs and are fragmented and, at higher velocities, thermally altered. Particles much larger than the foam cells behave as if the foam were a continuum, allowing the use of a continuum mechanics model to describe the effects of drag and ablation. Fragmentation is expected to be a major process, especially for aggregates of small grains. Calculations based on these arguments accurately predict experimental data and, for hypothetical IDPs, indicate that recovery of organic materials will be low for encounter velocities greater than 5 km/s. For an organic particle 100 micrometers in diameter, approx. 35% of the original mass would be collected in an impact at 5 km/s, dropping to approx. 10% at 10 km/s and approx. 0% at 15 km/s. For the same velocities the recovery ratios for troilite (FeS) are approx. 95%, 65%, and 50%, and for olivine (Mg2SiO4) they are approx. 98%, 80%, and 65%, demonstrating that inorganic materials are much more easily collected. The density of the collector material has only a second-order effect, changing the recovered mass by less than 10% of the original mass.

  16. Ion conductivity and transport by porous coordination polymers and metal-organic frameworks.

    PubMed

    Horike, Satoshi; Umeyama, Daiki; Kitagawa, Susumu

    2013-11-19

    Ion conduction and transport in solids are both interesting and useful and are found in widely distinct materials, from those in battery-related technologies to those in biological systems. Scientists have approached the synthesis of ion-conductive compounds in a variety of ways, in the areas of organic and inorganic chemistry. Recently, based on their ion-conducting behavior, porous coordination polymers (PCPs) and metal-organic frameworks (MOFs) have been recognized for their easy design and the dynamic behavior of the ionic components in the structures. These PCP/MOFs consist of metal ions (or clusters) and organic ligands structured via coordination bonds. They could have highly concentrated mobile ions with dynamic behavior, and their characteristics have inspired the design of a new class of ion conductors and transporters. In this Account, we describe the state-of-the-art of studies of ion conductivity by PCP/MOFs and nonporous coordination polymers (CPs) and offer future perspectives. PCP/MOF structures tend to have high hydrophilicity and guest-accessible voids, and scientists have reported many water-mediated proton (H(+)) conductivities. Chemical modification of organic ligands can change the hydrated H(+) conductivity over a wide range. On the other hand, the designable structures also permit water-free (anhydrous) H(+) conductivity. The incorporation of protic guests such as imidazole and 1,2,4-triazole into the microchannels of PCP/MOFs promotes the dynamic motion of guest molecules, resulting in high H(+) conduction without water. Not only the host-guest systems, but the embedding of protic organic groups on CPs also results in inherent H(+) conductivity. We have observed high H(+) conductivities under anhydrous conditions and in the intermediate temperature region of organic and inorganic conductors. The keys to successful construction are highly mobile ionic species and appropriate intervals of ion-hopping sites in the structures. Lithium (Li

  17. Synergistic effect of EUV from the laser-sustained detonation plasma in a ground-based atomic oxygen simulation on fluorinated polymers

    SciTech Connect

    Tagawa, Masahito; Abe, Shingo; Kishida, Kazuhiro; Yokota, Kumiko; Okamoto, Akio

    2009-01-05

    The contribution of extreme ultraviolet (EUV) from a laser-sustained plasma on the mass loss phenomenon of fluorinated polymer in a ground-based laser-detonation atomic oxygen beam source was evaluated. The atomic oxygen beam and EUV from the oxygen plasma were separated by the high-speed chopper wheel installed in the beam source. The mass changes of the fluorinated polymer and polyimide were measured from the frequency shift of the quartz crystal microbalance during the beam exposures. It has been made clear that the fluorinated polymer erodes by EUV exposure alone. In contrast, no erosion was detected for polyimide by EUV alone. The atomic oxygen-induced erosion was measured for both materials even without EUV exposure. However, no strong synergistic effect was observed for a fluorinated polymer even under the simultaneous exposure condition of atomic oxygen and EUV. Similar results were observed even in simultaneous exposure of atomic oxygen (without EUV) and 172 nm vacuum ultraviolet (VUV) from an excimer lamp. These experiments suggest that the primary origin of the accelerated erosion of fluorinated polymer observed in a laser detonation atomic oxygen source is not the EUV from the laser-sustained plasma.

  18. Synthesis of a photoresponsive polymer and its incorporation into an organic superlattice.

    SciTech Connect

    Morales, Alfredo Martin; Rondeau, Chris J.; McElhanon, James Ross; Cole, Phillip James

    2005-01-01

    The synthesis of a photoswitchable polymer by grafting an azobenzene dye to methacrylate followed by polymerization is presented. The azobenzene dye undergoes a trans-cis photoisomerization that causes a persistent change in the refractive index of cast polymer films. This novel polymer was incorporated into superlattices prepared by spin casting and the optical activity of the polymer was maintained. A modified coextruder that allows the rapid production of soft matter superlattices was designed and fabricated.

  19. Specific identification of fibrin polymers, fibrinogen degradation products, and crosslinked fibrin degradation products in plasma and serum with a new sensitive technique.

    PubMed

    Connaghan, D G; Francis, C W; Lane, D A; Marder, V J

    1985-03-01

    A new method is described for identifying low concentrations of circulating derivatives of fibrinogen and fibrin, even when present in heterogeneous mixtures. This technique is applicable to plasma and serum and uses electrophoresis in 2% agarose in the presence of sodium dodecyl sulfate (SDS) followed by immunological identification of separated derivatives, using radiolabeled antifibrinogen antiserum and autoradiography. Unique electrophoretic patterns distinguish plasmic derivatives of crosslinked fibrin from those of fibrinogen and also identify crosslinked fibrin polymers produced by the combined action of thrombin and factor XIII on fibrinogen. The assay is sensitive to a concentration of 0.1 micrograms/mL of fibrinogen in serum or plasma. Fibrin polymers, plasmic degradation products of fibrinogen, and plasmic degradation products of crosslinked fibrin were detected in the plasma or serum of a patient with disseminated intravascular coagulation. Plasmic derivatives of both fibrinogen and crosslinked fibrin appeared in serum in the course of fibrinolytic therapy for pulmonary embolism, whereas during acute myocardial infarction a marked increase in the proportion of fibrin polymers in plasma was found in comparison with normal controls. Thus, the procedure can distinguish between the simultaneous processes of fibrin polymer formation, fibrinogenolysis, and fibrinolysis, and is sufficiently sensitive to detect relevant quantities of derivatives in pathologic conditions.

  20. Temperature dependent sensor response caused by polymer-solvent interactions

    SciTech Connect

    Butler, M A

    1992-01-01

    Absorption of organic solvents by a range of polymers has been used as the chemical transduction mechanism for a variety of sensors. This paper examines the effect of the polymer-solvent interaction on the temperature dependence of the sensor response. Optical interferometric cavities are formed on the end of an optical fiber by plasma-deposition of a fluorocarbon polymer. Swelling of the polymer when exposed to various solvent vapors produces changes in the reflectivity of the fiber tip. The temperature dependence of the sensor response is related to the strength of the polymer-solvent interaction and the heat of vaporization of the solvent.

  1. Attachment of Poly(l-lactide) Nanoparticles to Plasma-Treated Non-Woven Polymer Fabrics Using Inkjet Printing.

    PubMed

    Ivanova, Tatiana V; Baier, Grit; Landfester, Katharina; Musin, Eduard; Al-Bataineh, Sameer A; Cameron, David C; Homola, Tomáš; Whittle, Jason D; Sillanpää, Mika

    2015-09-01

    Active dressings that based on fabric materials are an area of interest for the treatment of wounds. Poly(l-lactide) nanoparticles containing the antimicrobial agent octenidine can be controllably lysed by toxins released by pathogenic bacteria thus releasing antimicrobial material in response to the presence of the bacterial toxins and so counteracting the infection. We developed an integrated engineering solution that allows for the stable immobilisation of nanoparticles on non-woven fabrics. The process involves coating nanoparticles on non-woven polymer surfaces by using an inkjet printing process. In order to improve the adhesion and retention of the nanoparticles on the fabric, surface pretreatment of the non-woven fabric using plasma jet treatment can be applied to increase its surface energy. PMID:26013285

  2. Production of organic compounds in plasmas: a comparison among electric sparks, laser-induced plasmas, and UV light.

    PubMed

    Scattergood, T W; McKay, C P; Borucki, W J; Giver, L P; Van Ghyseghem, H; Parris, J E; Miller, S L

    1989-01-01

    The chemistry in planetary atmospheres that is induced by processes associated with high-temperature plasmas is of broad interest because such processes may explain many of the chemical species observed. There are at least two important phenomena that are known to generate plasmas (and shocks) in planetary atmospheres: lightning and meteor impacts. For both phenomena, rapid heating of atmospheric gases leads to formation of a high-temperature plasma which emits radiation and produces shock waves that propagate through the surrounding atmosphere. These processes initiate chemical reactions that can transform simple gases into more complex compounds. In order to study the production of organic compounds in plasmas (shocks), various mixtures of N2, CH4, and H2, modeling the atmosphere of Titan, were exposed to discrete sparks, laser-induced plasmas (LIP), an ultraviolet radiation. The yields of HCN and several simple hydrocarbons were measured by gas chromatography and compared to those calculated from a simple quenched thermodynamic equilibrium model. The agreement between experiment and theory was fair for HCN and C2H2. However, the agreement for C2H6 and the other hydrocarbons was poor, indicating that a more comprehensive theory is needed. Our experiments suggest that photolysis by ultraviolet light from the plasma is an important process in the synthesis. This was confirmed by the photolysis of gas samples exposed to the light but not to the shock waves emitted by the sparks. Hence, the results of these experiments demonstrate that the thermodynamic equilibrium theory does not adequately model lightning and meteor impacts and that photolysis must be included. Finally, the similarity in yields between the spark and the LIP experiments suggest that LIP provide valid and clean simulations of lightning and meteor impacts and that photolysis must be included. Finally, the similarity in yields between the spark and the LIP experiments suggests that LIP provide valid

  3. Facile synthesis of magnetic molecularly imprinted polymer: Perphenazine template and its application in urine and plasma analysis.

    PubMed

    Safdarian, Mehdi; Ramezani, Zahra; Ghadiri, Ata A

    2016-07-15

    Synthesis of magnetic iron oxide nanoparticles and its surface modification with methacrylic acid (MAA) was performed simultaneously by adding Fe(2+)/Fe(3+) to an alkaline MAA solution under nitrogen atmosphere. MAA coated magnetite (Fe3O4@MAA) has abundant reactive double bonds on the surface that can initiate polymerization. Magnetic molecularly imprinted polymers (MMIPs) were synthesized through distillation-precipitation polymerization of MAA as monomer, perphenazine (PPZ) as template, and ethylene glycol di-methacrylate (EGDMA) as cross linker on Fe3O4@MAA, with concise control of experimental conditions in about 90min. The produced super paramagnetic MMIPs can be separated from the solution in the presence of external magnetic field in less than 1min. Characterizations of the synthesized particles were performed by electron microscopes, thermo-gravimetric analysis (TGA), vibrating sample magnetometer (VSM), Fourier transform infrared (FT-IR) spectroscopy, and BET. The data showed that Fe3O4@MAA was well encapsulated in the polymer shell. The MMIPs showed high porosity. Moreover, MMIPs were used for rapid pre-concentration and separation of PPZ in human plasma and urine without any dilution and pretreatments using high performance liquid chromatography equipped with a photo diode array detector (HPLC-PDA). The calibration curve in urine and plasma has shown the same slope as the external calibration curve. Linear range of 20-5000ngmL(-1), and a detection limit of 5.3ngmL(-1) was obtained. The results showed 97.92% recovery along with the relative standard deviation of 6.07% (n=6) for 1μgmL(-1) PPZ. Pre-concentration factor was 13. The MMIPs adsorbed PPZ in 1min and then desorbed it by MeOH:HOAc in 2min. PMID:27302687

  4. Addition of Hetero-Atoms to the Polymer Film by Plasma Enhanced Polymerization and its Optical Properties

    NASA Astrophysics Data System (ADS)

    Moriki, Kazunori; Yumoto, Motoshige

    Plasma enhanced polymerization is an attractive technology to fabricate an optical polymer waveguide, because it has capability to provide an uniform thickness film on a substrate with various surface geometry, and to provide change of refractive index by controlling a proportion of source monomer mixing. In the present paper we discuss optical constants and molecule structures of the films added hetero-atoms, O, N and F in the CHx network of polymer. Refractive index of those films changes from 1.52 to 1.63 at 1.0 μm wavelength, depending on the variety of hetero-atoms. Fluorine atoms added into a film decreases refractive index of the film. Oxygen atoms added into a film, which form ester structure (- COO-), decrease refractive index of the film, and some O atoms token into a film as OH base will increase optical absorption in inferred region for optical communication. Nitrogen atoms added increase optical absorption due to forming NH2 base. Finally, sp3/sp2 fraction controlling in the film will be a suitable to control refractive index of the film for an optical waveguide, for example by using mixed monomer of C6H6 and C6H10.

  5. Mechanisms of Decomposition of Organic Compounds by Water Plasmas at Atmospheric Pressure

    NASA Astrophysics Data System (ADS)

    Narengerile; Nishioka, Hiroshi; Watanabe, Takayuki

    2011-08-01

    The decomposition of acetone, methanol, and ethanol by water plasmas at atmospheric pressure has been investigated using a direct current (DC) discharge. At torch powers of 910-1050 W and organic compound concentrations of 1-10 mol %, the decomposition rate of methanol was over 99.99%, while those of acetone and/or ethanol was 96-99%. The concentrations of H2 obtained were 65-71% in the effluent gas and the removal efficiencies of 90-95% for total organic carbon (TOC) were achieved in liquid effluent for any compounds by pyrolysis. Over 50 wt % carbon in acetone or ethanol fed as the plasma supporting gas was transformed into soot, while the soot formation was negligible during methanol decomposition. On the basis of the experimental results, the mechanisms of decomposition of organic compounds in water plasmas were proposed and the mechanism of soot formation was clarified for the first time.

  6. Semiconducting organic-inorganic nanocomposites by intimately tethering conjugated polymers to inorganic tetrapods.

    PubMed

    Jung, Jaehan; Yoon, Young Jun; Lin, Zhiqun

    2016-04-28

    Semiconducting organic-inorganic nanocomposites were judiciously crafted by placing conjugated polymers in intimate contact with inorganic tetrapods via click reaction. CdSe tetrapods were first synthesized by inducing elongated arms from CdSe zincblende seeds through seed-mediated growth. The subsequent effective inorganic ligand treatment, followed by reacting with short bifunctional ligands, yielded azide-functionalized CdSe tetrapods (i.e., CdSe-N3). Finally, the ethynyl-terminated conjugated polymer poly(3-hexylthiophene) (i.e., P3HT-[triple bond, length as m-dash]) was tethered to CdSe-N3 tetrapods via a catalyst-free alkyne-azide cycloaddition, forming intimate semiconducting P3HT-CdSe tetrapod nanocomposites. Intriguingly, the intimate contact between P3HT and CdSe tetrapod was found to not only render the effective dispersion of CdSe tetrapods in the P3HT matrix, but also facilitate the efficient electronic interaction between these two semiconducting constituents. The successful anchoring of P3HT chains onto CdSe tetrapods was substantiated through Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy measurements. Moreover, the absorption and photoluminescence studies further corroborated the intimate tethering between P3HT and CdSe tetrapods. The effect of the type of bifunctional ligands (i.e., aryl vs. aliphatic ligands) and the size of tetrapods on the device performance of hybrid organic-inorganic solar cells was also scrutinized. Interestingly, P3HT-CdSe tetrapod nanocomposites produced via the use of an aryl bifunctional ligand (i.e., 4-azidobenzoic acid) exhibited an improved photovoltaic performance compared to that synthesized with their aliphatic ligand counterpart (i.e., 5-bromovaleric acid). Clearly, the optimal size of CdSe tetrapods ensuring the effective charge transport in conjunction with the good dispersion of CdSe tetrapods rendered an improved device performance. We envision that the click

  7. 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.

  8. All-solid-state lithium organic battery with composite polymer electrolyte and pillar[5]quinone cathode.

    PubMed

    Zhu, Zhiqiang; Hong, Meiling; Guo, Dongsheng; Shi, Jifu; Tao, Zhanliang; Chen, Jun

    2014-11-26

    The cathode capacity of common lithium ion batteries (LIBs) using inorganic electrodes and liquid electrolytes must be further improved. Alternatively, all-solid-state lithium batteries comprising the electrode of organic compounds can offer much higher capacity. Herein, we successfully fabricated an all-solid-state lithium battery based on organic pillar[5]quinone (C35H20O10) cathode and composite polymer electrolyte (CPE). The poly(methacrylate) (PMA)/poly(ethylene glycol) (PEG)-LiClO4-3 wt % SiO2 CPE has an optimum ionic conductivity of 0.26 mS cm(-1) at room temperature. Furthermore, pillar[5]quinine cathode in all-solid-state battery rendered an average operation voltage of ∼2.6 V and a high initial capacity of 418 mAh g(-1) with a stable cyclability (94.7% capacity retention after 50 cycles at 0.2C rate) through the reversible redox reactions of enolate/quinonid carbonyl groups, showing favorable prospect for the device application with high capacity.

  9. Characterization of polymer coated glass as a passive air sampler for persistent organic pollutants.

    PubMed

    Harner, Tom; Farrar, Nick J; Shoeib, Mahiba; Jones, Kevin C; Gobas, Frank A P C

    2003-06-01

    The use of thin-film polymer-coated glass surfaces or POGs as passive air samplers was investigated during an uptake experiment in an indoor environment with high levels of gas-phase polychlorinated biphenyls (PCBs). POGs consisted of a micron thick layer of ethylene vinyl acetate (EVA) coated onto glass cylinders. The uptake was initially linear with time and governed by the air-side mass transfer coefficient and surface area of the sampler. This was followed by a curvilinear region and finally a constant phase when equilibrium was established between air and EVA. The high surface area-to-volume ratio of the POGs allowed rapid equilibrium with gas-phase PCBs; equilibration times were on the order of hours for the low molecular weight congeners. The equilibrium concentration was dependent on the EVA-air partition coefficient, K(EVA-A), which was shown to be very well correlated to the octanol-air partition coefficient, K(OA). When POGs of varying thickness were equilibrated with air, the amount of PCB accumulated increased with increasing thickness of the EVA, indicating that uptake was by absorption into the entire polymer matrix. A wind field of 4 m s(-1) resulted in an increased uptake rate by a factor of approximately six compared to uptake in relatively still air. This wind speed effect was diminished, however, when POGs were housed in deployment chambers consisting of inverted stainless steel bowls. Relationships based on the air-side mass transfer coefficient and K(EVA-A) were developed for PCBs that describe the entire uptake profile and allow air concentrations to be determined from the amount of chemical accumulated in the POG. It is believed that these relationships are also valid when POGs are used to detect other classes of persistent organic pollutants. PMID:12831034

  10. Characterization of polymer coated glass as a passive air sampler for persistent organic pollutants.

    PubMed

    Harner, Tom; Farrar, Nick J; Shoeib, Mahiba; Jones, Kevin C; Gobas, Frank A P C

    2003-06-01

    The use of thin-film polymer-coated glass surfaces or POGs as passive air samplers was investigated during an uptake experiment in an indoor environment with high levels of gas-phase polychlorinated biphenyls (PCBs). POGs consisted of a micron thick layer of ethylene vinyl acetate (EVA) coated onto glass cylinders. The uptake was initially linear with time and governed by the air-side mass transfer coefficient and surface area of the sampler. This was followed by a curvilinear region and finally a constant phase when equilibrium was established between air and EVA. The high surface area-to-volume ratio of the POGs allowed rapid equilibrium with gas-phase PCBs; equilibration times were on the order of hours for the low molecular weight congeners. The equilibrium concentration was dependent on the EVA-air partition coefficient, K(EVA-A), which was shown to be very well correlated to the octanol-air partition coefficient, K(OA). When POGs of varying thickness were equilibrated with air, the amount of PCB accumulated increased with increasing thickness of the EVA, indicating that uptake was by absorption into the entire polymer matrix. A wind field of 4 m s(-1) resulted in an increased uptake rate by a factor of approximately six compared to uptake in relatively still air. This wind speed effect was diminished, however, when POGs were housed in deployment chambers consisting of inverted stainless steel bowls. Relationships based on the air-side mass transfer coefficient and K(EVA-A) were developed for PCBs that describe the entire uptake profile and allow air concentrations to be determined from the amount of chemical accumulated in the POG. It is believed that these relationships are also valid when POGs are used to detect other classes of persistent organic pollutants.

  11. Impact of an atmospheric argon plasma jet on a dielectric surface and desorption of organic molecules

    NASA Astrophysics Data System (ADS)

    Damany, Xavier; Pasquiers, Stéphane; Blin-Simiand, Nicole; Bauville, Gérard; Bournonville, Blandine; Fleury, Michel; Jeanney, Pascal; Santos Sousa, João

    2016-08-01

    The propagation of a DC-pulsed argon plasma jet through the surrounding ambient air, and its interaction with an ungrounded glass plate placed on the jet trajectory, was studied by means of fast imaging. The surface plays an important role in the spatio-temporal characteristics of the plasma. Indeed, for an argon jet propagating perpendicularly to the surface, the plasma jet structure changes from filamentary to diffuse when the distance between the nozzle of the capillary tube and the surface is short (≤10 mm). Changing the angle between the capillary tube and the glass plate, and varying the gas flow rate strongly affects the spatial extension of the plasma that develops on the surface. This surface plasma propagates while the plasma in the argon jet is maintained with the same luminous intensity. Finally, this plasma jet shows interesting characteristics for desorption of low volatile organic molecules such as bibenzyl. A maximum removal of bibenzyl is located at the intersection area between the jet axis and the glass surface, and some of the initially deposited molecules are found intact in gas phase. Contribution to the topical issue "6th Central European Symposium on Plasma Chemistry (CESPC-6)", edited by Nicolas Gherardi, Ester Marotta and Cristina Paradisi

  12. Optimization of Non-Thermal Plasma Treatment in an In Vivo Model Organism

    PubMed Central

    Lee, Amanda; Lin, Abraham; Shah, Kajol; Singh, Harpreet; Miller, Vandana; Gururaja Rao, Shubha

    2016-01-01

    Non-thermal plasma is increasingly being recognized for a wide range of medical and biological applications. However, the effect of non-thermal plasma on physiological functions is not well characterized in in vivo model systems. Here we use a genetically amenable, widely used model system, Drosophila melanogaster, to develop an in vivo system, and investigate the role of non-thermal plasma in blood cell differentiation. Although the blood system in Drosophila is primitive, it is an efficient system with three types of hemocytes, functioning during different developmental stages and environmental stimuli. Blood cell differentiation in Drosophila plays an essential role in tissue modeling during embryogenesis, morphogenesis and also in innate immunity. In this study, we optimized distance and frequency for a direct non-thermal plasma application, and standardized doses to treat larvae and adult flies so that there is no effect on the viability, fertility or locomotion of the organism. We discovered that at optimal distance, time and frequency, application of plasma induced blood cell differentiation in the Drosophila larval lymph gland. We articulate that the augmented differentiation could be due to an increase in the levels of reactive oxygen species (ROS) upon non-thermal plasma application. Our studies open avenues to use Drosophila as a model system in plasma medicine to study various genetic disorders and biological processes where non-thermal plasma has a possible therapeutic application. PMID:27505063

  13. A "roller-wheel" Pt-containing small molecule that outperforms its polymer analogs in organic solar cells

    DOE PAGES

    He, Wenhan; Wu, Qin; Livshits, Maksim Y.; Dickie, Diane A.; Yang, Jianzhong; Quinnett, Rachel; Rack, Jeffrey R.; Qin, Yang

    2016-05-23

    A novel Pt-bisacetylide small molecule (Pt-SM) featuring “roller-wheel” geometry was synthesized and characterized. When compared with conventional Pt-containing polymers and small molecules having “dumbbell” shaped structures, Pt-SM displays enhanced crystallinity and intermolecular π–π interactions, as well as favorable panchromatic absorption behaviors. Furthermore, organic solar cells (OSCs) employing Pt-SM achieve power conversion efficiencies (PCEs) up to 5.9%, the highest reported so far for Pt-containing polymers and small molecules.

  14. Plasma synthesis of lithium based intercalation powders for solid polymer electrolyte batteries

    SciTech Connect

    Kong, Peter C.; Pink, Robert J.; Nelson, Lee O.

    2005-01-04

    The invention relates to a process for preparing lithium intercalation compounds by plasma reaction comprising the steps of: forming a feed solution by mixing lithium nitrate or lithium hydroxide or lithium oxide and the required metal nitrate or metal hydroxide or metal oxide and between 10-50% alcohol by weight; mixing the feed solution with O.sub.2 gas wherein the O.sub.2 gas atomizes the feed solution into fine reactant droplets, inserting the atomized feed solution into a plasma reactor to form an intercalation powder; and if desired, heating the resulting powder to from a very pure single phase product.

  15. Plasma Synthesis of Lithium Based Intercalation Powders for Solid Polymer Electrolyte Batteries

    SciTech Connect

    Kong, Peter C.; Pink, Robert J.; Nelson, Lee O.

    2005-01-04

    The invention relates to a process for preparing lithium intercalation compounds by plasma reaction comprising the steps of: forming a feed solution by mixing lithium nitrate or lithium hydroxide or lithium oxide and the required metal nitrate or metal hydroxide or metal oxide and between 10-50% alcohol by weight; mixing the feed solution with O2 gas wherein the O2 gas atomizes the feed solution into fine reactant droplets, inserting the atomized feed solution into a plasma reactor to form an intercalation powder; and if desired, heating the resulting powder to form a very pure single phase product.

  16. Chemical and microstructural characterizations of plasma polymer films by time-of-flight secondary ion mass spectrometry and principal component analysis

    NASA Astrophysics Data System (ADS)

    Cossement, Damien; Renaux, Fabian; Thiry, Damien; Ligot, Sylvie; Francq, Rémy; Snyders, Rony

    2015-11-01

    It is accepted that the macroscopic properties of functional plasma polymer films (PPF) are defined by their functional density and their crosslinking degree (χ) which are quantities that most of the time behave in opposite trends. If the PPF chemistry is relatively easy to evaluate, it is much more challenging for χ. This paper reviews the recent work developed in our group on the application of principal component analysis (PCA) to time-of-flight secondary ion mass spectrometric (ToF-SIMS) positive spectra data in order to extract the relative cross-linking degree (χ) of PPF. NH2-, COOR- and SH-containing PPF synthesized in our group by plasma enhanced chemical vapor deposition (PECVD) varying the applied radiofrequency power (PRF), have been used as model surfaces. For the three plasma polymer families, the scores of the first computed principal component (PC1) highlighted significant differences in the chemical composition supported by X-Ray photoelectron spectroscopy (XPS) data. The most important fragments contributing to PC1 (loadings > 90%) were used to compute an average C/H ratio index for samples synthesized at low and high PRF. This ratio being an evaluation of χ, these data, accordingly to the literature, indicates an increase of χ with PRF excepted for the SH-PPF. These results have been cross-checked by the evaluation of functional properties of the plasma polymers namely a linear correlation with the stability of NH2-PPF in ethanol and a correlation with the mechanical properties of the COOR-PPF. For the SH-PPF family, the peculiar evolution of χ is supported by the understanding of the growth mechanism of the PPF from plasma diagnostic. The whole set of data clearly demonstrates the potential of the PCA method for extracting information on the microstructure of plasma polymers from ToF-SIMS measurements.

  17. Deposition of Polymer Thin Film Using an Atmospheric Pressure Micro-Plasma Driven by Dual-Frequency Excitation

    NASA Astrophysics Data System (ADS)

    Wang, Xiaomin; Yuan, Qianghua; Zhou, Yongjie; Yin, Guiqin; Dong, Chenzhong

    2014-01-01

    Polymer thin film deposition using an atmospheric pressure micro-plasma jet driven by dual-frequency excitations is described in this paper. The discharge process was operated with a mixture of argon (6 slm) and a small amount of acetone (0-2100 ppm). Plasma composition was measured by optical emission spectroscopy (OES). In addition to a large number of Ar spectra lines, we observed some spectra of C, CN, CH and C2. Through changing acetone content mixed in argon, we found that the optimum discharge condition for deposition can be characterized by the maximum concentration of carbonaceous species. The deposited film was characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy. The XPS indicated that the film was mostly composed of C with trace amount of O and N elements. The FTIR suggested different carbon-containing bonds (-CHx, C=O, C=C, C-O-C) presented in the deposited film.

  18. Polymer-silica hybrids for separation of CO2 and catalysis of organic reactions

    NASA Astrophysics Data System (ADS)

    Silva Mojica, Ernesto

    spectroscopic investigation of the interactions of CO 2 with amine molecules under simulated CO2 capture conditions. Industrial CO2 capture processes involve fluidization and require degradation-resistant sorbents in the form of pellets. Agglomeration of silica-based CO2 capture sorbents involved the formulation of a polymer binder solution and the design of a scalable pelletization process. The characterization of these pellets revealed the formation of a CO 2-permeable polymer-silica network, which is resistant to attrition, and exhibits similar CO2 capture and degradation performance as the non-pelletized sorbents. The performance of these sorbents and pellets was tested in lab-scale and bench-scale adsorption units, using in-house fabricated fixed-bed and fluidized-bed reactors. A compartmental modeling technique was used to simulate the CO2 adsorption process and to elucidate the kinetic and thermodynamic parameters that impact the commercial viability of emerging CO2 capture technologies. The fundamental concepts and experimental techniques developed for the preparation of CO2 capture sorbents served as a basis for fabricating amine-functionalized polymer-silica hybrids for applications in catalysis of organic reactions. (i) Basic catalysts for carbon-carbon addition reactions were prepared by immobilization of amine molecules on silica supports. The activity of these catalysts and the mechanisms of base-catalyzed organic condensation reactions were investigated by an in-situ FTIR micro-scale reactor. (ii) Particle-loaded PVA composite membranes were selected for immobilization of glucose oxidase (GOx). GOx was immobilized by adsorption at pH values between 3.5 and 7.1. The results showed that adsorption was primarily achieved via hydrophobic interactions, and that PVA membranes loaded with amine-functionalized particles could help retain the activity of immobilized GOx by providing a proper hydrophilic/hydrophobic balance to the immobilized enzymes micro-environment.

  19. pH-sensitive, polymer modified, plasma stable niosomes: promising carriers for anti-cancer drugs

    PubMed Central

    Tila, Dena; Yazdani-Arazi, Seyede Narjes; Ghanbarzadeh, Saeed; Arami, Sanam; Pourmoazzen, Zhaleh

    2015-01-01

    The aim of this study was the design and evaluation of a novel plasma stable, pH-sensitive niosomal formulation of Mitoxantrone by a modified ethanol injection method. Cholesterol hemisuccinate was added instead of cholesterol in order to produce pH-sensitivity property and using PEG-Poly (monomethyl itaconate)-CholC6 (PEG-PMMI-CholC6) copolymer introduced simultaneously pH-sensitivity and plasma stability properties in prepared niosomes. The pH-sensitivity and cytotoxicity of Mitoxantrone niosomes were evaluated in vitro in phosphate buffer with different pHs as well as using human ovarian cancer cell line (OVCAR-3), human breast cancer cell line (MCF-7) and human umbilical vein endothelial cells (HUVEC). Results showed that both cholesterol derivatives bearing formulations had pH-sensitive property and were found to release their contents under mild acidic conditions rapidly. In addition, the PEG-PMMI-CholC6-based niosomes could reserve the pH-sensitivity after incubation in plasma. Both Mitoxantrone-loaded pH-sensitive niosomes showed higher cytotoxicity than the conventional niosomes on OVCAR-3 and MCF-7 cell lines. However, both pH-sensitive niosomes exhibited lower cytotoxic effect on HUVEC cell line. Plasma stable, pH-sensitive niosomes could improve the cytotoxic effect and reduce the side effects of anti-tumor drugs. PMID:26417350

  20. Modified by air plasma polymer tack membranes as drainage material for antiglaucomatous operations

    NASA Astrophysics Data System (ADS)

    Ryazantseva, T. V.; Kravets, L. I.; Elinson, V. M.

    2014-06-01

    The morphological and clinical studies of poly(ethylene terephthalate) track membranes modified by air plasma as drainage materials for antiglaucomatous operations were performed. It was demonstrated their compatibility with eye tissues. Moreover, it was shown that a new drainage has a good lasting hypotensive effect and can be used as operation for refractory glaucoma surgery.

  1. Semiconducting organic-inorganic nanocomposites by intimately tethering conjugated polymers to inorganic tetrapods

    NASA Astrophysics Data System (ADS)

    Jung, Jaehan; Yoon, Young Jun; Lin, Zhiqun

    2016-04-01

    Semiconducting organic-inorganic nanocomposites were judiciously crafted by placing conjugated polymers in intimate contact with inorganic tetrapods via click reaction. CdSe tetrapods were first synthesized by inducing elongated arms from CdSe zincblende seeds through seed-mediated growth. The subsequent effective inorganic ligand treatment, followed by reacting with short bifunctional ligands, yielded azide-functionalized CdSe tetrapods (i.e., CdSe-N3). Finally, the ethynyl-terminated conjugated polymer poly(3-hexylthiophene) (i.e., P3HT-&z.tbd;) was tethered to CdSe-N3 tetrapods via a catalyst-free alkyne-azide cycloaddition, forming intimate semiconducting P3HT-CdSe tetrapod nanocomposites. Intriguingly, the intimate contact between P3HT and CdSe tetrapod was found to not only render the effective dispersion of CdSe tetrapods in the P3HT matrix, but also facilitate the efficient electronic interaction between these two semiconducting constituents. The successful anchoring of P3HT chains onto CdSe tetrapods was substantiated through Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy measurements. Moreover, the absorption and photoluminescence studies further corroborated the intimate tethering between P3HT and CdSe tetrapods. The effect of the type of bifunctional ligands (i.e., aryl vs. aliphatic ligands) and the size of tetrapods on the device performance of hybrid organic-inorganic solar cells was also scrutinized. Interestingly, P3HT-CdSe tetrapod nanocomposites produced via the use of an aryl bifunctional ligand (i.e., 4-azidobenzoic acid) exhibited an improved photovoltaic performance compared to that synthesized with their aliphatic ligand counterpart (i.e., 5-bromovaleric acid). Clearly, the optimal size of CdSe tetrapods ensuring the effective charge transport in conjunction with the good dispersion of CdSe tetrapods rendered an improved device performance. We envision that the click-reaction strategy enabled by

  2. Molecularly imprinted polymers for the pre-concentration of polar organic micropollutants for compound-specific isotope analysis

    NASA Astrophysics Data System (ADS)

    Bakkour, Rani; Hofstetter, Thomas B.

    2014-05-01

    Compound-specific isotope analysis (CSIA) is a promising tool for assessing transformations of polar organic micropollutants such as pesticides, pharmaceuticals and consumer chemicals in aquatic systems. There are, however, two major challenges: (1) Polar organic micropollutants occur at very low levels and, as a consequence, large amounts of water are required to achieve analyte enrichment with factors of 50'000 and more, inevitably leading to large interferences from the aqueous matrix. (2) The polarity of these micropollutants impedes the use of typical non-polar sorbates for solid-phase enrichment. In view of these challenges, the use of molecularly imprinted polymers (MIP) is a promising approach to produce tailor-made materials for highly selective enrichment of polar organic micropollutants with reduced matrix interferences. In this work, we explore the use of MIP to selectively enrich benzotriazoles, an important class of polar aquatic micropollutants. Polymers were synthesized in the presence of 5,6-dimethyl-1H-benzotriazole as a template, which leaves cavities in the polymer matrix with a very high affinity to the template and closely related structures including our main target analyte, 1H-benzotrizole. After extraction of the template, specific recognition of substituted benzotriazoles is expected by the synthesized MIPs. As the MIP has no specific affinity to the matrix, there is also expected to be negligible enrichment of the matrix. Retention factors of the MIP are compared for different synthetic procedures and to non-imprinted polymers where no specific intermolecular interactions with benzotriazoles are expected. Optimum performance of the MIP is demonstrated in this study in terms of the selectivity of enrichment, recoveries of analytes and the goodness of carbon and nitrogen isotope ratios measured by gas chromatography isotopic ratio mass spectrometry (GC/IRMS). This approach will enable us to enrich large amounts of aqueous samples while

  3. 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.

  4. The Integration and Applications of Organic Thin Film Transistors and Ferroelectric Polymers

    NASA Astrophysics Data System (ADS)

    Hsu, Yu-Jen

    Organic thin film transistors and ferroelectric polymer (polyvinylidene difluoride) sheet material are integrated to form various sensors for stress/strain, acoustic wave, and Infrared (heat) sensing applications. Different from silicon-based transistors, organic thin film transistors can be fabricated and processed in room-temperature and integrated with a variety of substrates. On the other hand, polyvinylidene difluoride (PVDF) exhibits ferroelectric properties that are highly useful for sensor applications. The wide frequency bandwidth (0.001 Hz to 10 GHz), vast dynamic range (100n to 10M psi), and high elastic compliance (up to 3 percent) make PVDF a more suitable candidate over ceramic piezoelectric materials for thin and flexible sensor applications. However, the low Curie temperature may have impeded its integration with silicon technology. Organic thin film transistors, however, do not have the limitation of processing temperature, hence can serve as transimpedance amplifiers to convert the charge signal generated by PVDF into current signal that are more measurable and less affected by any downstream parasitics. Piezoelectric sensors are useful for a range of applications, but passive arrays suffer from crosstalk and signal attenuation which have complicated the development of array-based PVDF sensors. We have used organic field effect transistors, which are compatible with the low Curie temperature of a flexible piezoelectric polymer,PVDF, to monolithically fabricate transimpedance amplifiers directly on the sensor surface and convert the piezoelectric charge signal into a current signal which can be detected even in the presence of parasitic capacitances. The device couples the voltage generated by the PVDF film under strain into the gate of the organic thin film transistors (OFET) using an arrangement that allows the full piezoelectric voltage to couple to the channel, while also increasing the charge retention time. A bipolar detector is created by

  5. Inactivation of food-borne spoilage and pathogenic micro-organisms on the surface of a photoactive polymer.

    PubMed

    Zerdin, Katherine; Scully, Andrew D

    2010-01-01

    The photodynamic action of a novel photoactive polymer comprising covalently bound anthraquinone (AQ) moieties was evaluated after developing a methodology to reliably immobilize viable micro-organisms onto polymer film surfaces. The survival of Escherichia coli, Bacillus cereus (vegetative cells and spores), Fusarium oxysporum and Saccharomyces cerevisiae microbes inoculated on the surface of inert polymeric substrates was assessed to determine the effect of inoculum composition, drying rate and exposure to ultraviolet (UV-A) radiation. Their survival was highly dependent on microbial genus, with E. coli consistently displaying markedly shorter survival times than the other microbes, and B. cereus spores being the most resistant. Inoculation of the microbes onto the surface of the photoactive polymer films, followed by exposure to UV-A radiation, dramatically accelerated the inactivation of all microbial types studied compared with their survival on the surface of inert polymer substrates. Simultaneous exposure to both oxygen and UV-A radiation is required to affect cell survival, which is consistent with this effect most likely originating from the photoinduced production of singlet oxygen by the photoactive polymer. These results provide further compelling evidence that singlet oxygen produced exogenously by this photoactive polymeric substrate can successfully inactivate a broad spectrum of microbes on the substrate's surface.

  6. Abatement of mixture of volatile organic compounds (VOCs) in a catalytic non-thermal plasma reactor.

    PubMed

    Karuppiah, J; Reddy, E Linga; Reddy, P Manoj Kumar; Ramaraju, B; Karvembu, R; Subrahmanyam, Ch

    2012-10-30

    Total oxidation of mixture of dilute volatile organic compounds was carried out in a dielectric barrier discharge reactor with various transition metal oxide catalysts integrated in-plasma. The experimental results indicated the best removal efficiencies in the presence of metal oxide catalysts, especially MnO(x), whose activity was further improved with AgO(x) deposition. It was confirmed water vapor improves the efficiency of the plasma reactor, probably due to the formation of hydroxyl species, whereas, in situ decomposition of ozone on the catalyst surface may lead to nascent oxygen. It may be concluded that non-thermal plasma approach is beneficial for the removal of mixture of volatile organic compounds than individual VOCs, probably due to the formation of reactive intermediates like aldehydes, peroxides, etc.

  7. 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

  8. Preparation and surface characterization of plasma-treated and biomolecular-micropatterned polymer substrates

    NASA Astrophysics Data System (ADS)

    Langowski, Bryan Alfred

    A micropatterning process creates distinct microscale domains on substrate surfaces that differ from the surfaces' original chemical/physical properties. Numerous micropatterning methods exist, each having relative advantages and disadvantages in terms of cost, ease, reproducibility, and versatility. Polymeric surfaces micropatterned with biomolecules have many applications, but are specifically utilized in tissue engineering as cell scaffolds that attempt to controlled tissue generation in vivo and ex vivo. As the physical and chemical cues presented by micropatterned substrates control resulting cellular behavior, characterization of these cues via surface-sensitive analytical techniques is essential in developing cell scaffolds that mimic complex in vivo physicochemical environments. The initial focus of this thesis is the chemical and physical characterization of plasma-treated, microcontact-printed (muCP) polymeric substrates used to direct nerve cell behavior. Unmodified and oxygen plasma-treated poly(methyl methacrylate) (PMMA) substrates were analyzed by surface sensitive techniques to monitor plasma-induced chemical and physical modifications. Additionally, protein-micropattern homogeneity and size were microscopically evaluated. Lastly, poly(dimethylsiloxane) (PDMS) stamps and contaminated PMMA substrates were characterized by spectroscopic and microscopic methods to identify a contamination source during microcontact printing. The final focus of this thesis is the development of microscale plasma-initiated patterning (muPIP) as a versatile, reproducible micropatterning method. Using muPIP, polymeric substrates were micropatterned with several biologically relevant inks. Polymeric substrates were characterized following muPIP by surface-sensitive techniques to identify the technique's underlying physical and chemical bases. In addition, neural stem cell response to muPIP-generated laminin micropatterns was microscopically and biologically evaluated

  9. Zwitterionic polymer-modified silicon microring resonators for label-free biosensing in undiluted human plasma

    PubMed Central

    Kirk, James T.; Brault, Norman D.; Baehr-Jones, Tom; Hochberg, Michael; Jiang, Shaoyi; Ratner, Daniel M.

    2013-01-01

    A widely acknowledged goal in personalized medicine is to radically reduce the costs of highly parallelized, small fluid volume, point-of-care and home-based diagnostics. Recently, there has been a surge of interest in using complementary metal-oxide-semiconductor (CMOS)-compatible silicon photonic circuits for biosensing, with the promise of producing chip-scale integrated devices containing thousands of orthogonal sensors, at minimal cost on a per-chip basis. A central challenge in biosensor translation is to engineer devices that are both sensitive and specific to a target analyte within unprocessed biological fluids. Despite advances in the sensitivity of silicon photonic biosensors, poor biological specificity at the sensor surface remains a significant factor limiting assay performance in complex media (i.e. whole blood, plasma, serum) due to the non-specific adsorption of proteins and other biomolecules. Here, we chemically modify the surface of silicon microring resonator biosensors for the label-free detection of an analyte in undiluted human plasma. This work highlights the first application of a non-fouling zwitterionic surface coating to enable silicon photonic-based label-free detection of a protein analyte at clinically relevant sensitivities in undiluted human plasma. PMID:23202337

  10. Plasma treatment of polymer dielectric films to improve capacitive energy storage

    NASA Technical Reports Server (NTRS)

    Yializis, A.; Binder, M.; Mammone, R. J.

    1994-01-01

    Demand for compact instrumentation, portable field equipment, and new electromagnetic weapons is creating a need for new dielectric materials with higher energy storage capabilities. Recognizing the need for higher energy storage capacitors, the Army Research Lab at Fort Monmouth, NJ, initiated a program a year ago to investigate potential methods for increasing the dielectric strength of polyvinylidene difluoride (PVDF) film, which is the highest energy density material commercially available today. Treatment of small area PVDF films in a CF4/O2 plasma showed that the dielectric strength of PVDF films can be increased by as much as 20 percent when treated in a 96 percent CF4/4 percent O2 plasma. This 44 percent increase in energy storage of a PVDF capacitor is significant considering that the treatment can be implemented in a conventional metallizing chamber, with minimum capital investment. The data shows that improved breakdown strength may be unique to PVDF film and the particular CF4/O2 gas mixture, because PVDF film treated with 100 percent CF4, 100 percent O2, Ar gas plasma, and electron irradiation shows no improvement in breakdown strength. Other data presented includes dissipation factor, dielectric constant, and surface tension measurements.

  11. Superior Charge Storage and Power Density of a Conducting Polymer-Modified Covalent Organic Framework

    PubMed Central

    2016-01-01

    The low conductivity of two-dimensional covalent organic frameworks (2D COFs), and most related coordination polymers, limits their applicability in optoelectronic and electrical energy storage (EES) devices. Although some networks exhibit promising conductivity, these examples generally lack structural versatility, one of the most attractive features of framework materials design. Here we enhance the electrical conductivity of a redox-active 2D COF film by electropolymerizing 3,4-ethylenedioxythiophene (EDOT) within its pores. The resulting poly(3,4-ethylenedioxythiophene) (PEDOT)-infiltrated COF films exhibit dramatically improved electrochemical responses, including quantitative access to their redox-active groups, even for 1 μm-thick COF films that otherwise provide poor electrochemical performance. PEDOT-modified COF films can accommodate high charging rates (10–1600 C) without compromising performance and exhibit both a 10-fold higher current response relative to unmodified films and stable capacitances for at least 10 000 cycles. This work represents the first time that electroactive COFs or crystalline framework materials have shown volumetric energy and power densities comparable with other porous carbon-based electrodes, thereby demonstrating the promise of redox-active COFs for EES devices. PMID:27725966

  12. Self-Assembly Directed Organization of Nanodiamond During Ionic Liquid Crystalline Polymer Formation.

    PubMed

    Ringstrand, Bryan S; Seifert, Sönke; Podlesak, David W; Firestone, Millicent A

    2016-07-01

    The UV-initiated free radical polymerization of a lyotropic mesophase prepared by co-assembly of an aqueous mixture of an ionic liquid (IL) monomer, 3-decyl-1-vinylimidazolium chloride, in a dimethyl sulfoxide dispersion of an IL-monomer nanodiamond conjugate yields a well-ordered 2D hexagonally structured network-polymer composite. The IL monomer is covalently bound to carboxylated detonation diamond via ester-linked 3-decyl-1-vinylimidazolium bromide. Successful preparation of the amphiphile-functionalized nanodiamond is determined by ATR/FT-IR, thermogravimetric analysis, and small-angle X-ray scattering (SAXS). Mesophase and composite structure are evaluated by SAXS, revealing a columnar architecture composed of amphiphilic ionic liquid cylinders containing solvent-rich cores. Self-assembly directed site localization of the nanodiamond positions the particles in the alkyl chain continuum upon polymerization. The composite reversibly swells in ethanol allowing structural variation and modulation of the nanoparticle internal packing arrangement. This work demonstrates that through careful molecular design, self-organization and site-directed assembly of nanodiamond into chemically distinct regions of a nanostructured organogel can be achieved. PMID:27197942

  13. Synthesis of polymer latex particles decorated with organically-modified laponite clay platelets via emulsion polymerization.

    PubMed

    Herrera, Norma Negrete; Persoz, Stéphanie; Putaux, Jean-Luc; David, Laurent; Bourgeat-Lami, Elodie

    2006-02-01

    We report a new route to colloidal nanocomposites consisting of polymer latex particles covered with Laponite clay nanoplatelets. These composite particles are prepared by seeded emulsion (co)polymerization of styrene and butyl acrylate from Laponite clay suspensions previously functionalized by ion exchange using either a free radical initiator: 2,2-azobis (2-methylpropionamidine) hydrochloride (AIBA) or a cationic vinyl monomer: 2-(methacryloyloxy) ethyl trimethyl ammonium chloride (MADQUAT). The successful intercalation of the cationic reactive molecules was confirmed by elemental analysis, FTIR, 13C solid-state NMR and WAXD. The organically-modified clays were dispersed into water with the help of tetrasodium pyrophosphate and an anionic surfactant. stable latexes, produced under different experimental conditions, were successfully obtained from the clay suspensions. Cryo-TEM images of the resulting latexes showed spherical composite particles with diameters in the 50-250 nm range with clay sheets located on their surface. This paper reports on the effect of the processing conditions on the particle morphology and latex stability, and describes the mechanism of formation of the nanocomposite particles.

  14. Ionic liquid-based zwitterionic organic polymer monolithic column for capillary hydrophilic interaction chromatography.

    PubMed

    Wang, Tingting; Chen, Yihui; Ma, Junfeng; Zhang, Xiaodan; Zhang, Lihua; Zhang, Yukui

    2015-08-21

    In the current study, a novel ionic liquid-based zwitterionic organic polymer monolithic column was developed by copolymerizing 1-vinyl-3-(butyl-4-sulfonate) imidazolium, acrylamide and N,N'-methylenebisacrylamide in a quaternary porogenic solvent consisting of formamide, dimethyl sulphoxide, polyethylene glycol 8000 and polyethylene glycol 10,000 for capillary hydrophilic interaction chromatography. The monolithic stationary phase was optimized by adjusting the amount of monomer in the polymerization solution along with the composition of porogenic solvent. The optimized monolith exhibited excellent selectivity and favorable retention for nucleosides and benzoic acid derivatives. The primary factors affecting the separation efficiency of the monolithic column (including acetonitrile content, pH, and buffer salt concentration in the mobile phase) have been thoroughly evaluated. Excellent reproducibility of the retention times for five nucleosides was achieved, with relative standard deviations of run-to-run (n = 3), column-to-column (n = 3) and batch-to-batch (n = 3) in the range of 0.18-0.48%, 2.33-4.20% and 3.07-6.50%, respectively.

  15. Lateral actuation of an organic droplet on conjugated polymer electrodes via imbalanced interfacial tensions.

    PubMed

    Xu, Wei; Xu, Jian; Li, Xin; Tian, Ye; Choi, Chang-Hwan; Yang, Eui-Hyeok

    2016-08-17

    This paper presents a new mechanism for the controlled lateral actuation of organic droplets on dodecylbenzenesulfonate-doped polypyrrole (PPy(DBS)) electrodes at low voltages (∼0.9 V) in an aqueous environment. The droplet actuation is based on the tunable surface wetting properties of the polymer electrodes induced by electrochemical redox reactions. The contact angle of a dichloromethane (DCM) droplet on the PPy(DBS) surface switches between ∼119° upon oxidation (0.6 V) and ∼150° upon reduction (-0.9 V) in 0.1 M NaNO3 solution. The droplet placed across the reduced and oxidized PPy(DBS) electrodes experiences imbalanced interfacial tensions, which prompt the actuation of the droplet from the reduced electrode to the oxidized electrode. The lateral actuation of DCM droplets on two PPy(DBS) electrodes is demonstrated, and the actuation process is studied. The driving force due to the imbalanced interfacial tensions is estimated to be approximately 10(-7) N for a 6 μL droplet. PMID:27426489

  16. How disorder controls the kinetics of triplet charge recombination in semiconducting organic polymer photovoltaics.

    PubMed

    Bittner, Eric R; Lankevich, Vladimir; Gélinas, Simon; Rao, Akshay; Ginger, David A; Friend, Richard H

    2014-10-14

    Recent experiments by Rao et al. (Nature, 2013, 500, 435-439) indicate that recombination of triplet charge-separated states is suppressed in organic polymer-fullerene based bulk-heterojunction (BHJ) photovoltaic cells exhibiting a high degree of crystallinity in the fullerene phase relative to systems with more disorder. In this paper, we use a series of Frenkel-exciton lattice models to rationalize these results in terms of wave-function localization, interface geometry, and density of states. In one-dimensional co-linear and co-facial models of the interface, increasing local energetic disorder in one phase localizes the interfacial triplet charge-transfer ((3)CT) states and increases the rate at which these states relax to form lower-energy triplet excitons. In two dimensional BHJ models, energetic disorder within the fullerene phase plays little role in further localizing states pinned to the interface. However, inhomogeneous broadening introduces strong coupling between the interfacial (3)CT and nearby fullerene triplet excitons and can enhance the decay of these states in systems with higher degrees of energetic disorder.

  17. Highly optimized CO2 capture by inexpensive nanoporous covalent organic polymers and their amine composites.

    PubMed

    Patel, Hasmukh A; Yavuz, Cafer T

    2015-01-01

    Carbon dioxide (CO2) storage and utilization requires effective capture strategies that limit energy penalties. Polyethylenimine (PEI)-impregnated covalent organic polymers (COPs) with a high CO2 adsorption capacity are successfully prepared in this study. A low cost COP with a high specific surface area is suitable for PEI loading to achieve high CO2 adsorption, and the optimal PEI loading is 36 wt%. Though the adsorbed amount of CO2 on amine impregnated COPs slightly decreased with increasing adsorption temperature, CO2/N2 selectivity is significantly improved at higher temperatures. The adsorption of CO2 on the sorbent is very fast, and a sorption equilibrium (10% wt) was achieved within 5 min at 313 K under the flow of simulated flue gas streams. The CO2 capture efficiency of this sorbent is not affected under repetitive adsorption-desorption cycles. The highest CO2 capture capacity of 75 mg g(-1) at 0.15 bar is achieved under dry CO2 capture however it is enhanced to 100 mg g(-1) in the mixed gas flow containing humid 15% CO2. Sorbents were found to be thermally stable up to at least 200 °C. TGA and FTIR studies confirmed the loading of PEIs on COPs. This sorbent with high and fast CO2 sorption exhibits a very promising application in direct CO2 capture from flue gas.

  18. Design of hybrid conjugated polymer materials: 1) Novel inorganic/organic hybrid semiconductors and 2) Surface modification via grafting approaches

    NASA Astrophysics Data System (ADS)

    Peterson, Joseph J.

    The research presented in this dissertation focuses on the design and synthesis of novel hybrid conjugated polymer materials using two different approaches: (1) inorganic/organic hybrid semiconductors through the incorporation of carboranes into the polymer structure and (2) the modification of surfaces with conjugated polymers via grafting approaches. Hybrid conjugated polymeric materials, which are materials or systems in which conjugated polymers are chemically integrated with non-traditional structures or surfaces, have the potential to harness useful properties from both components of the material to help overcome hurdles in their practical realization in polymer-based devices. This work is centered around the synthetic challenges of creating new hybrid conjugated systems and their potential for advancing the field of polymer-based electronics through both greater understanding of the behavior of hybrid systems, and access to improved performance and new applications. Chapter 1 highlights the potential applications and advantages for these hybrid systems, and provides some historical perspective, along with relevant background materials, to illustrate the rationale behind this work. Chapter 2 explores the synthesis of poly(fluorene)s with pendant carborane cages. The Ni(0) dehalogenative polymerization of a dibromofluorene with pendant carborane cages tethered to the bridging 9-position produced hybrid polymers produced polymers which combined the useful emissive characteristics of poly(fluorene) with the thermal and chemical stability of carborane cages. The materials were found to display increased glass transition temperatures and showed improved emission color stability after annealing at high temperatures relative to the non-hybrid polymer. The design and synthesis of a poly(fluorene)-based hybrid material with carborane cages in the backbone, rather than as pendant groups, begins in chapter 3. Poly(fluorene) with p-carborane in the backbone is

  19. Intimate organic-inorganic nanocomposites via rationally designed conjugated polymer-grafted precursors.

    PubMed

    Jung, Jaehan; Yoon, Young Jun; Lin, Zhiqun

    2016-09-28

    Semiconducting organic-inorganic nanocomposites comprising the conjugated polymer poly(3-hexylthiophene) (P3HT) in intimate contact with CdSe nanocrystals were crafted by exploiting rationally designed P3HT-grafted cadmium precursors (i.e., Cd-P3HT complexes). The bifunctional ligand 4-bromobenzyl phosphonic acid (BPA-Br) that possesses two terminal functional groups at each end was employed, enabling the coordination of BPA-Br with Cd first to yield Cd-phosphonic acid complexes (Cd-BPA-Br) followed by the subsequent substitution of the bromide moiety into the azide (N3) group to form N3-functionalized Cd-phosphonic acid complexes (Cd-BPA-N3). Cd-P3HT complexes were then synthesized via a click reaction between Cd-BPA-N3 and ethynyl-terminated P3HT (P3HT-[triple bond, length as m-dash]). The success of the click reaction was confirmed by spectroscopic measurements. The morphology of CdSe nanocrystals (i.e., quantum dot and multi-branched) in P3HT-CdSe nanocrystal nanocomposites can be altered by tuning the concentration of Cd-P3HT complexes and the addition of excess Cd-BPA-Br (i.e., Cd-P3HT solely for the synthesis of CdSe quantum dots, and Cd-P3HT and Cd-BPA-Br at the ratio Cd-P3HT : Cd-BPA-Br = 1 : 1 for the synthesis of multi-branched CdSe nanocrystals). The photophysical properties of the resulting P3HT-CdSe nanocomposites were examined via absorption and photoluminescence studies. In comparison with P3HT-[triple bond, length as m-dash], the significant emission quenching of nanocomposites suggested the efficient charge transfer at the P3HT/CdSe interface. It is noteworthy that the implementation of judiciously synthesized Cd-P3HT complexes as precursors rendered the in situ synthesis of P3HT-CdSe nanocrystal nanocomposites, dispensing with the need for the use of insulating aliphatic ligands and tedious ligand exchange procedures for the preparation of functional polymer-tethered nanocrystals. PMID:27604874

  20. Etching method for photoresists or polymers

    NASA Technical Reports Server (NTRS)

    Lerner, Narcinda R. (Inventor); Wydeven, Theodore J., Jr. (Inventor)

    1991-01-01

    A method for etching or removing polymers, photoresists, and organic contaminants from a substrate is disclosed. The method includes creating a more reactive gas species by producing a plasma discharge in a reactive gas such as oxygen and contacting the resulting gas species with a sacrificial solid organic material such as polyethylene or polyvinyl fluoride, reproducing a highly reactive gas species, which in turn etches the starting polymer, organic contaminant, or photoresist. The sample to be etched is located away from the plasma glow discharge region so as to avoid damaging the substrate by exposure to high energy particles and electric fields encountered in that region. Greatly increased etching rates are obtained. This method is highly effective for etching polymers such as polyimides and photoresists that are otherwise difficult or slow to etch downstream from an electric discharge in a reactive gas.

  1. Experimental and in silico investigations of organic phosphates and phosphonates sorption on polymer-ceramic monolithic materials and hydroxyapatite.

    PubMed

    Pietrzyńska, Monika; Zembrzuska, Joanna; Tomczak, Rafał; Mikołajczyk, Jakub; Rusińska-Roszak, Danuta; Voelkel, Adam; Buchwald, Tomasz; Jampílek, Josef; Lukáč, Miloš; Devínsky, Ferdinand

    2016-10-10

    A method based on experimental and in silico evaluations for investigating interactions of organic phosphates and phosphonates with hydroxyapatite was developed. This quick and easy method is used for determination of differences among organophosphorus compounds of various structures in their mineral binding affinities. Empirical sorption evaluation was carried out using liquid chromatography with tandem mass spectrometry or UV-VIS spectroscopy. Raman spectroscopy was used to confirm sorption of organic phosphates and phosphonates on hydroxyapatite. Polymer-ceramic monolithic material and bulk hydroxyapatite were applied as sorbent materials. Furthermore, a Polymer-ceramic Monolithic In-Needle Extraction device was used to investigate both sorption and desorption steps. Binding energies were computed from the fully optimised structures utilising Density Functional Theory (DFT) at B3LYP/6-31+G(d,p) level. Potential pharmacologic and toxic effects of the tested compounds were estimated by the Prediction of the Activity Spectra of Substances using GeneXplain software. PMID:27552905

  2. Comparison of the Behavior of Polymers in Supercritical Fluids and Organic Solvents Via Small Angle Neutron Scattering

    SciTech Connect

    Melnichenko, Y.B.; Kiran, E.; Heath, K.D.; Salaniwal, S.; Cochran, H.D.; Stamm, M.; Van Hook, W.A.; Wignall, G.D.

    1999-05-17

    Small-angle neutron scattering has been used to study the effect of temperature and pressure on the phase behavior of semidilute solutions of polymers dissolved in organic and supercritical solvents. Above the theta temperature (To), these systems exhibit a ''good solvent'' domain, where the molecules expand beyond the unperturbed dimensions in both organic solvents and in COZ. However, this transition can be made to occur at a critical ''theta pressure'' (PO) in CO2 and this represents a new concept in the physics of polymer-solvent systems. For T < To, and P < Po, the system enters the ''poor solvent'' domain where diverging concentration fluctuations prevent the chains from collapsing and allow them to maintain their unperturbed dimensions.

  3. Positive and negative TiO2 micropatterns on organic polymer substrates.

    PubMed

    Yang, Peng; Yang, Min; Zou, Shengli; Xie, Jingyi; Yang, Wantai

    2007-02-14

    Ordered titanium dioxide (TiO2) films have received increasing attention because of their great potential in photocatalysis, energy conversion, and electrooptical techniques. Such films are often fabricated as coatings on various substrates such as silicon or a variety of polymers. Liquid-phase deposition (LPD) of TiO2 films is especially promising for organic substrates due to its very mild reaction conditions. In the present paper, LPD is conducted on a wettability-patterned polypropylene surface to fabricate positive and negative TiO2 micropatterns. A thin layer of ammonium persulfate in an aqueous solution was sandwiched between two biaxially oriented polypropylene (BOPP) films, and a photomask was employed to control the irradiation region. Within a short time interval, a high hydrophilicity could be obtained on the irradiation region, and an effective wettability contrast between the irradiated and unirradiated regions could be created to further induce the formation of two types of TiO2 micropatterns. Up until now, most approaches for micropatterning have been based on self-assembled monolayers on surfaces of gold (or other noble metals), silicon, and various polyesters. With the present method, however, there is no longer any limitation in the type of substrate used. Our work demonstrates that an anatase TiO2 film could be selectively deposited on a hydrophilic region, giving rise to a positive pattern with significant bonding strength and good line edge acuity, providing an effective solution toward the microfabrication on various inert polymer substrates. More surprisingly, we find, for the first time, that TiO2 could also be selectively retained on a hydrophobic region to form a negative pattern by simply adjusting the reaction conditions. Further analysis of the mechanism shows that, independent of the deposition conditions, the TiO2 deposition pattern changes gradually, from being initially negative to becoming positive as the deposition time increases

  4. ``Living polymers'' in organic solvents : stress relaxation in bicopper tetracarboxylate/tert-butyl cyclohexane solutions

    NASA Astrophysics Data System (ADS)

    Terech, P.; Maldivi, P.; Dammer, C.

    1994-10-01

    Viscoelastic solutions of a bicopper tetracarboxylate complex in tert-butylcyclohexane have been studied by dynamic rheology in a wide range of concentrations (0.5-1.5 % volume fraction). The zero shear viscosity, the elastic modulus, the terminal stress relaxation time and the height of the high-frequency dip, in a Cole-Cole representation of the complex elastic modulus, follow scaling laws. The related exponents are discussed in the context of the physics of “living polymers” : a term used to describe worm-like species undergoing scission/recombination reactions competing mainly with the reptation motions of the chains. The current system, made up of molecular threads (17.5 Å diameter) of Cu2(O2C-CH(C2H5)C4H9)4 in the apolar solvent, is representative of a “living polymer” where, instead of mechanisms involving transient star polymeric crosslinks, a reversible scission mechanism prevails. The dynamics in the high-frequency range evolves from a regime where reptation is the dominant relaxation mechanism to a cross-over regime where “breathing” fluctuations and Rouse motions become important. Large modifications of the stress relaxation function occur for more concentrated systems. The binary system is the first example of a “living polymer” in an organic solvent and exhibits elastic moduli (G ≈ ca. 120 Pa à φ = 1 %) which are at least 20 times larger than those found for the aqueous “living polymer” systems. Les solutions viscoélastiques d'un tétracarboxylate binucléaire de cuivre dans le tert-butylcyclohexane sont étudiées par rhéologie en mode dynamique dans une gamme étendue de concentrations (0,5 %-15,5 %). La viscosité à gradient nul, le module élastique, le temps terminal de relaxation et la hauteur du puits à haute fréquence, dans une représentation Cole-Cole du module élastique complexe, suivent des lois d'échelles. Les exposants correspondants sont discutés dans le contexte de la physique des “polymères vivants

  5. Unsubstituted Benzodithiophene-Based Conjugated Polymers for High-Performance Organic Field-Effect Transistors and Organic Solar Cells.

    PubMed

    Chen, Weichao; Xiao, Manjun; Han, Liangliang; Zhang, Jidong; Jiang, Huanxiang; Gu, Chuantao; Shen, Wenfei; Yang, Renqiang

    2016-08-01

    Unsubstituted benzo[1,2-b:4,5-b']dithiophene (BDT) was used to construct a high-performance conjugated polymer with 5,6-difluoro-4,7-bis[4-(2-octyldodecyl)thiophene-2-yl]benzo[c][1,2,5] thiadiazole (DTFFBT), named PBDT-DTFFBT. The polymer shows the low-lying highest occupied molecular orbital (HOMO) energy level (-5.40 eV) and a broad absorption spectra with strong vibronic absorption peak. Pure polymer films exhibit good crystallinity and edge-on orientation, partially attributed to the BDT units without any side chains, and as a result, the corresponding thin-film transistor showed excellent hole mobility over 1 cm(2) V(-1) s(-1). Interestingly, a well-distributed nanofibrillar polymer aggregation with face-on orientation was obviously formed when blending with PC71BM, which was in favor of the charge transportation. Consequently, the bulk heterojunction polymer solar cells based on the blends showed high power conversion efficiency of 9.29% with large short-current density (14.56 mA cm(-2)) and high fill factor (0.751) without any process additives or thermal annealing. PMID:27403850

  6. Unsubstituted Benzodithiophene-Based Conjugated Polymers for High-Performance Organic Field-Effect Transistors and Organic Solar Cells.

    PubMed

    Chen, Weichao; Xiao, Manjun; Han, Liangliang; Zhang, Jidong; Jiang, Huanxiang; Gu, Chuantao; Shen, Wenfei; Yang, Renqiang

    2016-08-01

    Unsubstituted benzo[1,2-b:4,5-b']dithiophene (BDT) was used to construct a high-performance conjugated polymer with 5,6-difluoro-4,7-bis[4-(2-octyldodecyl)thiophene-2-yl]benzo[c][1,2,5] thiadiazole (DTFFBT), named PBDT-DTFFBT. The polymer shows the low-lying highest occupied molecular orbital (HOMO) energy level (-5.40 eV) and a broad absorption spectra with strong vibronic absorption peak. Pure polymer films exhibit good crystallinity and edge-on orientation, partially attributed to the BDT units without any side chains, and as a result, the corresponding thin-film transistor showed excellent hole mobility over 1 cm(2) V(-1) s(-1). Interestingly, a well-distributed nanofibrillar polymer aggregation with face-on orientation was obviously formed when blending with PC71BM, which was in favor of the charge transportation. Consequently, the bulk heterojunction polymer solar cells based on the blends showed high power conversion efficiency of 9.29% with large short-current density (14.56 mA cm(-2)) and high fill factor (0.751) without any process additives or thermal annealing.

  7. Polyurethane coating with thin polymer films produced by plasma polymerization of diglyme

    NASA Astrophysics Data System (ADS)

    Ribeiro, M. A.; Ramos, A. S.; Manfredini, M. I.; Alves, H. A.; Y Honda, R.; Kostov, K. G.; Lucena, E. F.; Ramos, E. C. T.; Mota, R. P.; Algatti, M. A.; Kayama, M. E.

    2009-05-01

    Aqueous-based polyurethane dispersions have been widely utilized as lubricants in textile, shoes, automotive, biomaterial and many other industries because they are less aggressive to surrounding environment. In this work thin films with different thickness were deposited on biocompatible polyurethane by plasma polymerization process using diethylene glycol dimethyl ether (Diglyme) as monomer. Molecular structure of the films was analyzed by Fourier Transform Infrared spectroscopy. The spectra exhibited absorption bands of O-H (3500-3200cm-1), C-H (3000-2900cm-1), C=O (1730-1650cm-1), C-O and C-O-C bonds at 1200-1600cm-1. The samples wettability was evaluated by measurements of contact angle using different liquids such as water, glycerol, poly-ethane and CMC. The polyurethane surface showed hydrophilic behavior after diglyme plasma-deposition with contact angle dropping from 85° to 22°. Scanning Electron Microscopy revealed that diglyme films covered uniformly the polyurethane surfaces ensuring to it a biocompatible characteristic.

  8. Accelerated cell-surface interlocking on plasma polymer-modified porous ceramics.

    PubMed

    Rebl, Henrike; Finke, Birgit; Schmidt, Jürgen; Mohamad, Heba S; Ihrke, Roland; Helm, Christiane A; Nebe, J Barbara

    2016-12-01

    Excellent osseointegration of permanent implants is crucial for the long lasting success of the implantation. To improve the osseointegrative potential, bio-inert titanium alloy surfaces (Ti6Al4V) are modified by plasma chemical oxidation (PCO®) of the titanium-oxide layer to a non-stoichiometric, amorphous calcium phosphate layer. The native titanium-oxide film measuring only a few nanometers is converted by PCO® to a thick porous calcium phosphate layer of about 10μm. In a second step the PCO surface is combined with a cell adhesive plasma-polymerized allylamine (PPAAm) nano film (5 and 50nm). Independent of the PPAAm coating homogeneity, the human osteoblast-like MG-63 cells show a remarkable increase in cell size and well-developed filopodia. Analyses of the actin cytoskeleton reveal that the cells mold to the pore shape of the PPAAm-covered PCO, thereby establishing a strong attachment to the surface. Interestingly, we could demonstrate that even though our untreated PCO shows excellent hydrophilicity, this alone is not sufficient to facilitate fast cell spreading, but the positive surface charges mediated by PPAAm. This multilayer composite material guarantees enhanced interlocking of the cells with the porous surface.

  9. Accelerated cell-surface interlocking on plasma polymer-modified porous ceramics.

    PubMed

    Rebl, Henrike; Finke, Birgit; Schmidt, Jürgen; Mohamad, Heba S; Ihrke, Roland; Helm, Christiane A; Nebe, J Barbara

    2016-12-01

    Excellent osseointegration of permanent implants is crucial for the long lasting success of the implantation. To improve the osseointegrative potential, bio-inert titanium alloy surfaces (Ti6Al4V) are modified by plasma chemical oxidation (PCO®) of the titanium-oxide layer to a non-stoichiometric, amorphous calcium phosphate layer. The native titanium-oxide film measuring only a few nanometers is converted by PCO® to a thick porous calcium phosphate layer of about 10μm. In a second step the PCO surface is combined with a cell adhesive plasma-polymerized allylamine (PPAAm) nano film (5 and 50nm). Independent of the PPAAm coating homogeneity, the human osteoblast-like MG-63 cells show a remarkable increase in cell size and well-developed filopodia. Analyses of the actin cytoskeleton reveal that the cells mold to the pore shape of the PPAAm-covered PCO, thereby establishing a strong attachment to the surface. Interestingly, we could demonstrate that even though our untreated PCO shows excellent hydrophilicity, this alone is not sufficient to facilitate fast cell spreading, but the positive surface charges mediated by PPAAm. This multilayer composite material guarantees enhanced interlocking of the cells with the porous surface. PMID:27612809

  10. Structural features of polymer adsorbent LiChrolut EN and interfacial behavior of water and water/organic mixtures.

    PubMed

    Gun'ko, V M; Turov, V V; Zarko, V I; Nychiporuk, Y M; Goncharuk, E V; Pakhlov, E M; Yurchenko, G R; Kulik, T V; Palyanytsya, B B; Borodavka, T V; Krupskaya, T V; Leboda, R; Skubiszewska-Zieba, J; Osovskii, V D; Ptushinskii, Y G; Turov, A V

    2008-07-01

    The structural and adsorption characteristics of polymer adsorbent LiChrolut EN and the behavior of adsorbed water and water/organic mixtures were studied using adsorption, microcalorimetry, transmission and scanning electron microscopy, mass spectrometry, infrared spectroscopy, 1H NMR spectroscopy with layer-by-layer freezing-out of liquids (190-273 K), and thermally stimulated depolarization current method (90-265 K). This adsorbent is characterized by large specific surface area (approximately 1500 m2/g) and pore volume (0.83 cm3/g) with a major contribution of narrow pores (R<10 nm) of a complicated shape (long hysteresis loop is in nitrogen adsorption-desorption isotherm). The adsorbent includes aromatic and aliphatic structures and oxygen-containing functionalities and can effectively adsorb organics and water/organic mixtures. On co-adsorption of water and organics (dimethyl sulfoxide, chloroform, methane), there is a weak influence of one on another adsorbate due to their poor mixing in pores. Weakly polar chloroform displaces a fraction of water from narrow pores. These effects can explain high efficiency of the adsorbent in solid-phase extraction of organics from aqueous solutions. The influence of structural features of several carbon and polymer adsorbents on adsorbed nitrogen, water and water/organics is compared on the basis of the adsorption and 1H NMR data. PMID:18440015

  11. Plasma membrane-associated platforms: dynamic scaffolds that organize membrane-associated events.

    PubMed

    Astro, Veronica; de Curtis, Ivan

    2015-03-10

    Specialized regions of the plasma membrane dedicated to diverse cellular processes, such as vesicle exocytosis, extracellular matrix remodeling, and cell migration, share a few cytosolic scaffold proteins that associate to form large plasma membrane-associated platforms (PMAPs). PMAPs organize signaling events and trafficking of membranes and molecules at specific membrane domains. On the basis of the intrinsic disorder of the proteins constituting the core of these PMAPs and of the dynamics of these structures at the periphery of motile cells, we propose a working model for the assembly and turnover of these platforms.

  12. Severe Leptospirosis with Multiple Organ Failure Successfully Treated by Plasma Exchange and High-Volume Hemofiltration

    PubMed Central

    Bourquin, Vincent; Ponte, Belén; Hirschel, Bernard; Pugin, Jérôme; Martin, Pierre-Yves; Saudan, Patrick

    2011-01-01

    Background. Leptospirosis is a spirochetal zoonosis with complex clinical features including renal and liver failure. Case report. We report the case of a Swiss fisherman presenting with leptospirosis. After initial improvement, refractory septic shock and severe liver and kidney failure developed. The expected mortality was estimated at 90% with clinical scores. The patient underwent plasma exchanges and high-volume hemofiltration (HVHF) with complete recovery of hepatic and kidney functions. Discussion. Plasma exchanges and HVHF may confer survival benefit on patients with severe leptospirosis, refractory septic shock, and multiple-organ failure. PMID:24527237

  13. Tokamak plasma self-organization and the possibility to have the peaked density profile in ITER

    NASA Astrophysics Data System (ADS)

    Razumova, K. A.; Andreev, V. F.; Kislov, A. Ya.; Kirneva, N. A.; Lysenko, S. E.; Pavlov, Yu. D.; Shafranov, T. V.; T-10 Team; Donné, A. J. H.; Hogeweij, G. M. D.; Spakman, G. W.; Jaspers, R.; TEXTOR Team; Kantor, M.; Walsh, M.

    2009-06-01

    The self-organization of a tokamak plasma is a fundamental turbulent plasma phenomenon, which leads to the formation of a self-consistent pressure profile. This phenomenon has been investigated in several tokamaks with different methods of heating. It is shown that the normalized pressure profile has a universal shape for a wide class of tokamaks and regimes, if the normalized radius ρ = r/(IpR/κB)1/2 is used. The consequences of this phenomenon for low aspect ratio tokamaks, the optimal deposition of additional heating, fast velocity of heat/cold pulse propagation and the possibility of obtaining a peaked density profile in ITER are discussed.

  14. The effect of novel nitrogen-rich plasma polymer coatings on the phenotypic profile of notochordal cells

    PubMed Central

    Mwale, Fackson; Wang, Hong Tian; Petit, Alain; Girard-Lauriault, Pierre-Luc; Hunter, Christopher J; Ouellet, Jean A; Wertheimer, Michael R; Antoniou, John

    2007-01-01

    Background The loss of the notochordal cells from the nucleus pulposus is associated with ageing and disc degeneration. However, understanding the mechanisms responsible for the loss of these cells has been hampered in part due to the difficulty of culturing and maintaining their phenotype. Furthermore, little is known about the influence of the substratum on the molecular markers of notochordal cells. Methods Notochordal cells were isolated from lumbar spine of non-chondrodystrophoid dogs and cultured on N-rich plasma polymer layers, so-called "PPE:N" (N-doped plasma-polymerised ethylene, containing up to 36% [N]) surfaces, for 3, 7 or 14 days. Gene expression of vimentin (VIM), pleiotrophin (PTN), matrix Gla protein (MGP), cartilage oligomeric matrix protein (COMP), keratin 18 (KRT 18), aggrecan (AGG), collagen type 1 (COL1A2), collagen type 2 (COL2A1) was analyzed through semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). Results Notochordal cells were maintained in culture on PPE:N for up to 14 days with no loss in cell viability. Except for VIM, gene expression varied depending on the culture periods and [N] concentration of the substratum. Generally, PPE:N surfaces altered gene expression significantly when cells were cultured for 3 or 7 days. Conclusion The present study has shown that notochordal cells from dogs can attach to and grow on PPE:N surfaces. Analysis of the expression of different genes in these cells cultured on different N-functionalized surfaces indicates that cellular behaviour is gene-specific and time-dependent. Further studies are required to better understand the roles of specific surface functionalities on receptor sites, and their effects on cellular phenotypes. PMID:17822560

  15. Rationally designed molecularly imprinted polymers for selective extraction of methocarbamol from human plasma.

    PubMed

    Gholivand, Mohammad Bagher; Khodadadian, Mehdi

    2011-09-15

    Molecularly imprinted polymers (MIPs) with high selectivity toward methocarbamol have been computationally designed and synthesized based on the general non-covalent molecular imprinting approach. A virtual library consisting of 18 functional monomers was built and possible interactions between the template and functional monomers were investigated using a semiempirical approach. The monomers with the highest binding scores were then considered for additional calculations using a more accurate quantum mechanical (QM) calculation exploiting the density functional theory (DFT) at B3LYP/6-31G(d,p) level. The cosmo polarizable continuum model (CPCM) was also used to simulate the polymerization solvent. On the basis of computational results, acrylic acid (AA) and tetrahydrofuran (THF) were found to be the best choices of functional monomer and polymerization solvent, respectively. MIPs were then synthesized by the precipitation polymerization method and used as selective adsorbents to develop a molecularly imprinted solid-phase extraction (MISPE) procedure before quantitative analysis. After MISPE the drug could be determined either by differential pulse voltammetry (DPV), on a glassy carbon electrode modified with multiwalled-carbon nanotubes (GC/MWNT), or high performance chromatography (HPLC) with UV detection. A comparative study between MISPE-DPV and MISPE-HPLC-UV was performed. The MISPE-DPV was more sensitive but both techniques showed similar accuracy and precision. PMID:21807239

  16. Two novel metal–organic coordination polymers based on diphosphonate and oxalate: Synthesis, structures and properties

    SciTech Connect

    Niu, Qing-Jun; Zheng, Yue-Qing Zhou, Lin-Xia; Zhu, Hong-Lin

    2015-07-15

    Two 2-(1-imidazole)-1-hydroxyl-1,1'-ethylidenediphosphonato and oxalic acid bridged coordination polymers (H{sub 2}en)[Co{sub 3}(H{sub 2}zdn){sub 2}(ox)(H{sub 2}O){sub 2}] (1) and Cd{sub 2}(H{sub 2}zdn)(ox){sub 0.5}(H{sub 2}O) (2) (2-(1-imidazole)-1-hydroxyl-1,1'-ethylidenediphosphonic acid=H{sub 5}zdn; oxalic acid=H{sub 2}ox) were synthesized under hydrothermal conditions and characterized by the infrared (IR), thermogravimetric analyses (TGA), elemental analyses (EA) and X-ray diffraction (XRD). Compound 1 is bridged by phosphonate anions to 1D chain, and further linked by oxalate anions to 2D layer. Compound 2 is bridged by O–P–O units of H{sub 5}zdn to the layer, and then pillared by oxalate anions to generate 3D frameworks. Compound 1 shows anti-ferromagnetic behaviors analyzed with the temperature-dependent zero-field ac magnetic susceptibilities, while compound 2 exhibits an influence on the luminescent property. - Graphical abstract: Linked by oxalate, two zoledronate-based metal–organic frameworks are synthesized, which exhibits the different frameworks. Magnetism and luminescent properties have been studied. The weak antiferromagnetic coupling is conducted in 1. - Highlights: • Compound 1 and 2 are first linked by oxalate anion based on zoledronic acid. • Compound 1 generates a classic “dia Diamond” (6{sup 6}) topology. • Compound 2 exhibits a (4{sup 4}·6{sup 2})(4{sup 4}·6{sup 6}) topology. • Magnetism and luminescent properties of 1 and 2 have been studied, respectively.

  17. Photoinduced absorption measurement on a microchip equipped with organic dye-doped polymer waveguide

    NASA Astrophysics Data System (ADS)

    Kawaguchi, T.; Nagai, K.; Yamashita, K.

    2013-05-01

    We have fabricated a waveguide-type optical sensing microchip and succeeded in on-chip photoinduced absorption (PIA) spectroscopy. The PIA microchip was fabricated with a conventional photolithographic technique and consisted of plastic optical waveguides and microfluidic channels. Furthermore, a serially-cascaded polymer waveguide doped with organic dyes was integrated on this microchip, which was fabricated using a self-written waveguide process. This dye-doped waveguide was pumped by a UV light emitting diode (UV-LED) and used as a probe light source with a broad emission spectrum. At the same time, a solution of test material in the microfluidic channel was synchronously pumped by a UV-LED or UV laser diode. Since the transmission spectrum of the photo-excited test material could be measured, the PIA spectra were obtained easily. In this study, we have demonstrated the on-chip PIA measurements for two classes of test materials, rare-earth complex and chlorophyll molecules. In the measurement for the aqueous solution of Neodymium (III) acetate hydrate, PIA signals attributed to the 4f-4f transition was observed. Furthermore, by varying the modulation frequency of the pulsed optical pumping, lifetime analysis of the excited 4f states was achieved. In the measurements for the ethanol solutions of chlorophyll a and chlorophyll b, PIA signals were observed at the wavelength near the Q-band absorption peaks. These spectra were very similar to the well-known feature for the photosystem II protein complex observed in a conventional PIA system. From these results, it is expected that the onchip PIA measurement technique is applicable to the transient analyses for the material systems with photoexcited charge transfer.

  18. [Preparation and evaluation of pepsin affinity organic polymer capillary monolithic column].

    PubMed

    Chi, Cuijie; Wang, Wei; Ji, Yibing

    2014-08-01

    The protein modified monolithic column in affinity capillary electrochromatography (CEC) has attracted considerable attention over the past decades because of its great enantioseparation ability. A porous polymethacrylate ester-based capillary monolithic column poly (glycidyl methacrylate-co-ethyleneglycol dimethacrylate) (poly (GMA-co-EDMA)) was prepared by in situ co-polymerization. The process was initiated thermally by azobisisobutyronitrile (AIBN). The polymerization mixture contained GMA as the function monomer and EDMA as the crosslinking agent with 1,4-butanediol and 1-propanol as the binary porogen solvent. Under the optimized reaction conditions, including the proportion of monomer and porogens, reaction temperature etc, the column exhibited a uniform structure, sufficient permeability and excel- lent pressure resistance. The separation of alkyl benzenes on the column was mainly based on typical reversed-phase chromatographic retention mechanism. The reproducibility and stability were good with RSDs less than 9. 0%. A pepsin functionalized organic polymer monolith was prepared by covalently bonded pepsin to poly(GMA-co-EDMA) monolith with glutaraldehyde as a spacer based on the activity of epoxide group. The enantioseparation performance of the pepsin affinity monolith for basic enantiomers has been investigated by CEC. Nefopam, amlodipine, citalopram and chlorpheniramine were resolved, and baseline separations of nefopam, amlodipine, citalopram were achieved. The influences of pH, operating voltage, temperature and sample quantity used on the chiral separation were studied. The chiral recognition mechanism of enantiomers on the monolithic column in CEC is discussed. This work developed a new method for the prepataion and application of protein affinity monolith in CEC.

  19. High CO2-capture ability of a porous organic polymer bifunctionalized with carboxy and triazole groups.

    PubMed

    Xie, Lin-Hua; Suh, Myunghyun Paik

    2013-08-26

    A new porous organic polymer, SNU-C1, incorporating two different CO2 -attracting groups, namely, carboxy and triazole groups, has been synthesized. By activating SNU-C1 with two different methods, vacuum drying and supercritical-CO2 treatment, the guest-free phases, SNU-C1-va and SNU-C1-sca, respectively, were obtained. Brunauer-Emmett-Teller (BET) surface areas of SNU-C1-va and SNU-C1-sca are 595 and 830 m(2) g(-1), respectively, as estimated by the N2-adsorption isotherms at 77 K. At 298 K and 1 atm, SNU-C1-va and SNU-C1-sca show high CO2 uptakes, 2.31 mmol  g(-1) and 3.14 mmol  g(-1), respectively, the high level being due to the presence of abundant polar groups (carboxy and triazole) exposed on the pore surfaces. Five separation parameters for flue gas and landfill gas in vacuum-swing adsorption were calculated from single-component gas-sorption isotherms by using the ideal adsorbed solution theory (IAST). The data reveal excellent CO2-separation abilities of SNU-C1-va and SNU-C1-sca, namely high CO2-uptake capacity, high selectivity, and high regenerability. The gas-cycling experiments for the materials and the water-treated samples, experiments that involved treating the samples with a CO2-N2 gas mixture (15:85, v/v) followed by a pure N2 purge, further verified the high regenerability and water stability. The results suggest that these materials have great potential applications in CO2 separation.

  20. VUV-induced nitriding of polymer surfaces: Comparison with plasma treatments in nitrogen

    NASA Astrophysics Data System (ADS)

    Truica-Marasescu, F.; Guimond, S.; Wertheimer, M. R.

    2003-08-01

    Film samples of two very pure polyolefins (low density polyethylene and biaxially oriented polypropylene) have been surface-modified by two different methods, vacuum ultraviolet (VUV) photochemistry in low pressure ammonia, and atmospheric pressure glow discharge plasma treatment in N 2 gas. The results of these two treatments are compared, namely surface compositions (determined by X-ray photoelectron spectroscopy and infrared spectroscopy, ATR-FTIR) and surface energies (determined by contact angle goniometry with several probe liquids). We show that higher concentrations, [N], can be achieved by VUV photochemistry (up to 25%), that N is predominantly bonded as amine or amide groups, and that there exist certain particularities specific to each of the treatment methods investigated.

  1. Optically controllable dual-gate organic transistor produced via phase separation between polymer semiconductor and photochromic spiropyran molecules.

    PubMed

    Ishiguro, Yasushi; Hayakawa, Ryoma; Chikyow, Toyohiro; Wakayama, Yutaka

    2014-07-01

    We produced an optically controllable dual-gate organic field-effect transistor by a simple one-step spin-coating of a mixed solution of photochromic spiropyran (SP) and poly(3-hexylthiophene) (P3HT). Postannealing enhanced polymer chain ordering of P3HT to induce phase separation into an SP-rich lower layer and an SP-free upper layer. These layers worked independently as transistor channels with distinct optical responsivity. The top channel was optically inactive, but the bottom channel was optically active, because of the photoisomerization of SP. These results demonstrate the potential of our technique to produce a multifunctional photoactive organic transistor by a simple process.

  2. 25 Years of Self-organized Criticality: Space and Laboratory Plasmas

    NASA Astrophysics Data System (ADS)

    Sharma, A. Surjalal; Aschwanden, Markus J.; Crosby, Norma B.; Klimas, Alexander J.; Milovanov, Alexander V.; Morales, Laura; Sanchez, Raul; Uritsky, Vadim

    2016-01-01

    Studies of complexity in extended dissipative dynamical systems, in nature and in laboratory, require multiple approaches and the framework of self-organized criticality (SOC) has been used extensively in the studies of such nonequilibrium systems. Plasmas are inherently nonlinear and many ubiquitous features such as multiscale behavior, intermittency and turbulence have been analyzed using SOC concepts. The role of SOC in advancing our understanding of space and laboratory plasmas as nonequilibrium systems is reviewed in this article. The main emphasis is on how SOC and related approaches have provided new insights and models of nonequilibrium plasma phenomena. Among the natural plasmas the magnetosphere, driven by the solar wind, is a prominent example and extensive data from ground-based and space-borne instruments have been used to study phenomena of direct relevance to space weather, viz. geomagnetic storms and substorms. During geomagnetically active periods the magnetosphere is far from equilibrium, due to its internal dynamics and being driven by the turbulent solar wind, and substorms are prominent features of the complex driven system. Studies using solar wind and magnetospheric data have shown both global and multiscale features of substorms. While the global behavior exhibits system-wide changes, the multiscale behavior shows scaling features. Along with the studies based on observational data, analogue models of the magnetosphere have advanced the understanding of space plasmas as well as the role of SOC in natural systems. In laboratory systems, SOC has been used in modeling the plasma behavior in fusion experiments, mainly in tokamaks and stellarators. Tokamaks are the dominant plasma confinement system and modeling based on SOC have provided a complementary approach to the understanding of plasma behavior under fusion conditions. These studies have provided insights into key features of toroidally confined plasmas, e.g., the existence of critical

  3. 25 Years of Self-organized Criticality: Space and Laboratory Plasmas

    NASA Astrophysics Data System (ADS)

    Sharma, A. Surjalal; Aschwanden, Markus J.; Crosby, Norma B.; Klimas, Alexander J.; Milovanov, Alexander V.; Morales, Laura; Sanchez, Raul; Uritsky, Vadim

    2015-12-01

    Studies of complexity in extended dissipative dynamical systems, in nature and in laboratory, require multiple approaches and the framework of self-organized criticality (SOC) has been used extensively in the studies of such nonequilibrium systems. Plasmas are inherently nonlinear and many ubiquitous features such as multiscale behavior, intermittency and turbulence have been analyzed using SOC concepts. The role of SOC in advancing our understanding of space and laboratory plasmas as nonequilibrium systems is reviewed in this article. The main emphasis is on how SOC and related approaches have provided new insights and models of nonequilibrium plasma phenomena. Among the natural plasmas the magnetosphere, driven by the solar wind, is a prominent example and extensive data from ground-based and space-borne instruments have been used to study phenomena of direct relevance to space weather, viz. geomagnetic storms and substorms. During geomagnetically active periods the magnetosphere is far from equilibrium, due to its internal dynamics and being driven by the turbulent solar wind, and substorms are prominent features of the complex driven system. Studies using solar wind and magnetospheric data have shown both global and multiscale features of substorms. While the global behavior exhibits system-wide changes, the multiscale behavior shows scaling features. Along with the studies based on observational data, analogue models of the magnetosphere have advanced the understanding of space plasmas as well as the role of SOC in natural systems. In laboratory systems, SOC has been used in modeling the plasma behavior in fusion experiments, mainly in tokamaks and stellarators. Tokamaks are the dominant plasma confinement system and modeling based on SOC have provided a complementary approach to the understanding of plasma behavior under fusion conditions. These studies have provided insights into key features of toroidally confined plasmas, e.g., the existence of critical

  4. AFM, ellipsometry, XPS and TEM on ultra-thin oxide/polymer nanocomposite layers in organic thin film transistors.

    PubMed

    Fian, A; Haase, A; Stadlober, B; Jakopic, G; Matsko, N B; Grogger, W; Leising, G

    2008-03-01

    Here we report on the fabrication and characterization of ultra-thin nanocomposite layers used as gate dielectric in low-voltage and high-performance flexible organic thin film transistors (oTFTs). Reactive sputtered zirconia layers were deposited with low thermal exposure of the substrate and the resulting porous oxide films with high leakage currents were spin-coated with an additional layer of poly-alpha-methylstyrene (P alphaMS). After this treatment a strong improvement of the oTFT performance could be observed; leakage currents could be eliminated almost completely. In ellipsometric studies a higher refractive index of the ZrO(2)/P alphaMS layers compared to the "as sputtered" zirconia films could be detected without a significant enhancement of the film thickness. Atomic force microscopy (AFM) measurements of the surface topography clearly showed a surface smoothing after the P alphaMS coating. Further studies with X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) also indicated that the polymer definitely did not form an extra layer. The polymer chains rather (self-)assemble in the nano-scaled interspaces of the porous oxide film giving an oxide-polymer "nanocomposite" with a high oxide filling grade resulting in high dielectric constants larger than 15. The dielectric strength of more than 1 MV cm(-1) is in good accordance with the polymer-filled interspaces. PMID:17952415

  5. Self-organization in suspensions of end-functionalized semiflexible polymers under shear flow.

    PubMed

    Myung, Jin Suk; Winkler, Roland G; Gompper, Gerhard

    2015-12-28

    The nonequilibrium dynamical behavior and structure formation of end-functionalized semiflexible polymer suspensions under flow are investigated by mesoscale hydrodynamic simulations. The hybrid simulation approach combines the multiparticle collision dynamics method for the fluid, which accounts for hydrodynamic interactions, with molecular dynamics simulations for the semiflexible polymers. In equilibrium, various kinds of scaffold-like network structures are observed, depending on polymer flexibility and end-attraction strength. We investigate the flow behavior of the polymer networks under shear and analyze their nonequilibrium structural and rheological properties. The scaffold structure breaks up and densified aggregates are formed at low shear rates, while the structural integrity is completely lost at high shear rates. We provide a detailed analysis of the shear- rate-dependent flow-induced structures. The studies provide a deeper understanding of the formation and deformation of network structures in complex materials.

  6. Self-organization in suspensions of end-functionalized semiflexible polymers under shear flow

    NASA Astrophysics Data System (ADS)

    Myung, Jin Suk; Winkler, Roland G.; Gompper, Gerhard

    2015-12-01

    The nonequilibrium dynamical behavior and structure formation of end-functionalized semiflexible polymer suspensions under flow are investigated by mesoscale hydrodynamic simulations. The hybrid simulation approach combines the multiparticle collision dynamics method for the fluid, which accounts for hydrodynamic interactions, with molecular dynamics simulations for the semiflexible polymers. In equilibrium, various kinds of scaffold-like network structures are observed, depending on polymer flexibility and end-attraction strength. We investigate the flow behavior of the polymer networks under shear and analyze their nonequilibrium structural and rheological properties. The scaffold structure breaks up and densified aggregates are formed at low shear rates, while the structural integrity is completely lost at high shear rates. We provide a detailed analysis of the shear- rate-dependent flow-induced structures. The studies provide a deeper understanding of the formation and deformation of network structures in complex materials.

  7. `Inorganics-in-Organics': recent developments and outlook for 4G polymer solar cells

    NASA Astrophysics Data System (ADS)

    Jayawardena, K. D. G. Imalka; Rozanski, Lynn J.; Mills, Chris A.; Beliatis, Michail J.; Nismy, N. Aamina; Silva, S. Ravi P.

    2013-08-01

    Recent developments in solution processable single junction polymer solar cells have led to a significant improvement in power conversion efficiencies from ~5% to beyond 9%. While much of the initial efficiency improvements were driven through judicious design of donor polymers, it is the engineering of device architectures through the incorporation of inorganic nanostructures and better processing that has continued the efficiency gains. Inorganic nano-components such as carbon nanotubes, graphene and its derivatives, metal nanoparticles and metal oxides have played a central role in improving device performance and longevity beyond those achieved by conventional 3G polymer solar cells. The present work aims to summarise the diverse roles played by the nanosystems and features in state of the art next generation (4G) polymer solar cells. The challenges associated with the engineering of such devices for future deployment are also discussed.

  8. Effect of polymer aggregation on the open circuit voltage in organic photovoltaic cells: aggregation-induced conjugated polymer gel and its application for preventing open circuit voltage drop.

    PubMed

    Kim, Bong-Gi; Jeong, Eun Jeong; Park, Hui Joon; Bilby, David; Guo, L Jay; Kim, Jinsang

    2011-03-01

    To investigate the structure-dependent aggregation behavior of conjugated polymers and the effect of aggregation on the device performance of conjugated polymer photovoltaic cells, new conjugated polymers (PVTT and CN-PVTT) having the same regioregularity but different intermolecular packing were prepared and characterized by means of UV-vis spectroscopy and atomic force microscopy (AFM). Photovoltaic devices were prepared with these polymers under different polymer-aggregate conditions. Polymer aggregation induced by thermal annealing increases the short circuit current but provides no advantage in the overall power conversion efficiency because of a decrease in the open circuit voltage. The device fabricated from a pre-aggregated polymer suspension, acquired from ultrasonic agitation of a conjugated polymer gel, showed enhanced performance because of better phase separation and reduced recombination between polymer/PCBM.

  9. The surface properties of carbon fibers and their adhesion to organic polymers

    NASA Technical Reports Server (NTRS)

    Bascom, W. D.; Drzal, L. T.

    1987-01-01

    The state of knowledge of the surface properties of carbon fibers is reviewed, with emphasis on fiber/matrix adhesion in carbon fiber reinforced plastics. Subjects treated include carbon fiber structure and chemistry, techniques for the study of the fiber surface, polymer/fiber bond strength and its measurement, variations in polymer properties in the interphase, and the influence of fiber matrix adhesion on composite mechanical properties. Critical issues are summarized and search recommendations are made.

  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. Recent results on analytical plasma turbulence theory: Realizability, intermittency, submarginal turbulence, and self-organized criticality

    SciTech Connect

    Krommes, J.A.

    2000-01-18

    Recent results and future challenges in the systematic analytical description of plasma turbulence are described. First, the importance of statistical realizability is stressed, and the development and successes of the Realizable Markovian Closure are briefly reviewed. Next, submarginal turbulence (linearly stable but nonlinearly self-sustained fluctuations) is considered and the relevance of nonlinear instability in neutral-fluid shear flows to submarginal turbulence in magnetized plasmas is discussed. For the Hasegawa-Wakatani equations, a self-consistency loop that leads to steady-state vortex regeneration in the presence of dissipation is demonstrated and a partial unification of recent work of Drake (for plasmas) and of Waleffe (for neutral fluids) is given. Brief remarks are made on the difficulties facing a quantitatively accurate statistical description of submarginal turbulence. Finally, possible connections between intermittency, submarginal turbulence, and self-organized criticality (SOC) are considered and outstanding questions are identified.

  12. Observation of Multiple Reconnections during Self-organization Process of High Temperature Fusion Plasma

    NASA Astrophysics Data System (ADS)

    Park, H. K.; Tobias, B.; Choi, M. J.; Yun, G. S.; Domier, C. W.; Luhmann, N. C., Jr.; Munsat, T.; Donné, A. J. H.; Spakman, G. W.; Textor Team

    2011-10-01

    Images of a high resolution 2-D Electron Cyclotron Emission Imaging (ECEI) diagnostic shows evidence of multiple magnetic reconnection processes during the internal disruption of a high temperature tokamak plasmas. The disruption induces magnetic self-organization of the toroidal plasma being accompanied by successive or simultaneous multiple layer reconnection. The degree of asymmetric deformation of the internal magnetic structure (m/n=1/1 mode) prior to temperature crash influences the outcome of the disruptive behavior. The observation is critical for the building block of first principle theoretical modeling of the sawtooth oscillation in current driven toroidal plasmas and the understandings can be applied to the impulsive disruptive behavior in flares of the solar, accretion disk and stellar coronae, Earth magnetospheric storms, and controlled fusion. Work supported by the NRF of Korea, the US DOE, the NWO of the Netherlands, and the EURATOM-FOM association.

  13. Fabrication of water-stable organic transistors using crystalline rubrene thin-film and polymer-treated dielectric (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Kim, Jaejoon; Lee, Hyoek Moo; Cho, Sung Oh

    2015-10-01

    For the real application of organic electronics, stable operation of electronic devices in humid or aqueous condition is essential and desirable. However, most of organic semiconductors were very weak to the oxygen or water and especially, cannot be operated well in aqueous condition without an encapsulation. Here, we present water-stable organic thin-film transistors with highly crystallized rubrene and polymer-treated dielectrics. These high water-stability could be achieved by two factors. First, rubrene, a well-known p-type semiconducting material, showed high air and water stability after the crystallization of `abrupt heating'. By the fabrication and aqueous operation of rubrene thin film transistor, we could show the water stability of crystallized thin-film rubrene. Such high environmental stability is attributed to the fact that rubrene has comparatively low HOMO level of -5.4 eV and large bandgap energy of 3.2 eV and that the rubrene thin-film is composed of well-interconnected orthorhombic rubrene crystals. Second, the polymer-treatment of dielectrics can enhance long-term water stability of fabricated rubrene thin-film transistor. By the complete immersion test of transistors, we could characterize the increase of water-stability after the treatment of dielectrics with cross-linked polymer. For this purpose, polystyrene is cross-linked by electron irradiation and the water penetration into semiconductor/dielectric interface was decreased due to the decreased surface energy of polymer dielectric compared to the SiO₂. The fabricated rubrene thin-film transistors showed a field-effect mobility of ~0.5 cm2V-1s-1 and long-term stability under ambient and aqueous conditions. Also, we investigated their potential applications in chemical or bio sensors.

  14. Eisosomes promote the ability of Sur7 to regulate plasma membrane organization in Candida albicans

    PubMed Central

    Wang, Hong X.; Douglas, Lois M.; Veselá, Petra; Rachel, Reinhard; Malinsky, Jan; Konopka, James B.

    2016-01-01

    The plasma membrane of the fungal pathogen Candida albicans forms a protective barrier that also mediates many processes needed for virulence, including cell wall synthesis, invasive hyphal morphogenesis, and nutrient uptake. Because compartmentalization of the plasma membrane is believed to coordinate these diverse activities, we examined plasma membrane microdomains termed eisosomes or membrane compartment of Can1 (MCC), which correspond to ∼200-nm-long furrows in the plasma membrane. A pil1∆ lsp1∆ mutant failed to form eisosomes and displayed strong defects in plasma membrane organization and morphogenesis, including extensive cell wall invaginations. Mutation of eisosome proteins Slm2, Pkh2, and Pkh3 did not cause similar cell wall defects, although pkh2∆ cells formed chains of furrows and pkh3∆ cells formed wider furrows, identifying novel roles for the Pkh protein kinases in regulating furrows. In contrast, the sur7∆ mutant formed cell wall invaginations similar to those for the pil1∆ lsp1∆ mutant even though it could form eisosomes and furrows. A PH-domain probe revealed that the regulatory lipid phosphatidylinositol 4,5-bisphosphate was enriched at sites of cell wall invaginations in both the sur7∆ and pil1∆ lsp1∆ cells, indicating that this contributes to the defects. The sur7∆ and pil1∆ lsp1∆ mutants displayed differential susceptibility to various types of stress, indicating that they affect overlapping but distinct functions. In support of this, many mutant phenotypes of the pil1∆ lsp1∆ cells were rescued by overexpressing SUR7. These results demonstrate that C. albicans eisosomes promote the ability of Sur7 to regulate plasma membrane organization. PMID:27009204

  15. Novel red phosphorescent polymers bearing both ambipolar and functionalized Ir(III) phosphorescent moieties for highly efficient organic light-emitting diodes.

    PubMed

    Zhao, Jiang; Lian, Meng; Yu, Yue; Yan, Xiaogang; Xu, Xianbin; Yang, Xiaolong; Zhou, Guijiang; Wu, Zhaoxin

    2015-01-01

    A series of novel red phosphorescent polymers is successfully developed through Suzuki cross-coupling among ambipolar units, functionalized Ir(III) phosphorescent blocks, and fluorene-based silane moieties. The photophysical and electrochemical investigations indicate not only highly efficient energy-transfer from the organic segments to the phosphorescent units in the polymer backbone but also the ambipolar character of the copolymers. Benefiting from all these merits, the phosphorescent polymers can furnish organic light-emitting diodes (OLEDs) with exceptional high electroluminescent (EL) efficiencies with a current efficiency (η L ) of 8.31 cd A(-1) , external quantum efficiency (η ext ) of 16.07%, and power efficiency (η P ) of 2.95 lm W(-1) , representing the state-of-the-art electroluminescent performances ever achieved by red phosphorescent polymers. This work here might represent a new pathway to design and synthesize highly efficient phosphorescent polymers.

  16. Degradation of volatile organic compounds in a non-thermal plasma air purifier.

    PubMed

    Schmid, Stefan; Jecklin, Matthias C; Zenobi, Renato

    2010-03-01

    The degradation of volatile organic compounds in a commercially available non-thermal plasma based air purifying system was investigated. Several studies exist that interrogate the degradation of VOCs in closed air systems using a non-thermal plasma combined with a heterogeneous catalyst. For the first time, however, our study was performed under realistic conditions (normal indoor air, 297.5K and 12.5 g m(-3) water content) on an open system, in the absence of an auxiliary catalyst, and using standard operating air flow rates (up to 320 L min(-1)). Cyclohexene, benzene, toluene, ethylbenzene and the xylene isomers were nebulized and guided through the plasma air purifier. The degradation products were trapped by activated charcoal tubes or silica gel tubes, and analyzed using gas chromatography mass spectrometry. Degradation efficiencies of 11+/-1.6% for cyclohexene, <2% for benzene, 11+/-2.4% for toluene, 3+/-1% for ethylbenzene, 1+/-1% for sigma-xylene, and 3+/-0.4% for m-/rho-xylene were found. A fairly wide range of degradation products could be identified. On both trapping media, various oxidized species such as alcohols, aldehydes, ketones and one epoxide were observed. The formation of adipaldehyde from nebulized cyclohexene clearly indicates an ozonolysis reaction. Other degradation products observed suggests reactions with OH radicals. We propose that mostly ozone and OH radicals are responsible for the degradation of organic molecules in the plasma air purifier. PMID:20167347

  17. Analysis of a gas-liquid film plasma reactor for organic compound oxidation.

    PubMed

    Hsieh, Kevin; Wang, Huijuan; Locke, Bruce R

    2016-11-01

    A pulsed electrical discharge plasma formed in a tubular reactor with flowing argon carrier gas and a liquid water film was analyzed using methylene blue as a liquid phase hydroxyl radical scavenger and simultaneous measurements of hydrogen peroxide formation. The effects of liquid flow rate, liquid conductivity, concentration of dye, and the addition of ferrous ion on dye decoloration and degradation were determined. Higher liquid flow rates and concentrations of dye resulted in less decoloration percentages and hydrogen peroxide formation due to initial liquid conductivity effects and lower residence times in the reactor. The highest decoloration energy yield of dye found in these studies was 5.2g/kWh when using the higher liquid flow rate and adding the catalyst. The non-homogeneous nature of the plasma discharge favors the production of hydrogen peroxide in the plasma-liquid interface over the chemical oxidation of the organic in the bulk liquid phase and post-plasma reactions with the Fenton catalyst lead to complete utilization of the plasma-formed hydrogen peroxide. PMID:27267693

  18. Analysis of a gas-liquid film plasma reactor for organic compound oxidation.

    PubMed

    Hsieh, Kevin; Wang, Huijuan; Locke, Bruce R

    2016-11-01

    A pulsed electrical discharge plasma formed in a tubular reactor with flowing argon carrier gas and a liquid water film was analyzed using methylene blue as a liquid phase hydroxyl radical scavenger and simultaneous measurements of hydrogen peroxide formation. The effects of liquid flow rate, liquid conductivity, concentration of dye, and the addition of ferrous ion on dye decoloration and degradation were determined. Higher liquid flow rates and concentrations of dye resulted in less decoloration percentages and hydrogen peroxide formation due to initial liquid conductivity effects and lower residence times in the reactor. The highest decoloration energy yield of dye found in these studies was 5.2g/kWh when using the higher liquid flow rate and adding the catalyst. The non-homogeneous nature of the plasma discharge favors the production of hydrogen peroxide in the plasma-liquid interface over the chemical oxidation of the organic in the bulk liquid phase and post-plasma reactions with the Fenton catalyst lead to complete utilization of the plasma-formed hydrogen peroxide.

  19. Conformal organic-inorganic hybrid network polymer thin films by molecular layer deposition using trimethylaluminum and glycidol.

    PubMed

    Gong, Bo; Peng, Qing; Parsons, Gregory N

    2011-05-19

    Growing interest in nanoscale organic-inorganic hybrid network polymer materials is driving exploration of new bulk and thin film synthesis reaction mechanisms. Molecular layer deposition (MLD) is a vapor-phase deposition process, based on atomic layer deposition (ALD) which proceeds by exposing a surface to an alternating sequence of two or more reactant species, where each surface half-reaction goes to completion before the next reactant exposure. This work describes film growth using trimethyl aluminum and heterobifunctional glycidol at moderate temperatures (90-150 °C), producing a relatively stable organic-inorganic network polymer of the form (-Al-O-(C(4)H(8))-O-)(n). Film growth rate and in situ reaction analysis indicate that film growth does not initially follow a steady-state rate, but increases rapidly during early film growth. The mechanism is consistent with subsurface species transport and trapping, previously documented during MLD and ALD on polymers. A water exposure step after the TMA produces a more linear growth rate, likely by blocking TMA subsurface diffusion. Uniform and conformal films are formed on complex nonplanar substrates. Upon postdeposition annealing, films transform into microporous metal oxides with ∼5 Å pore size and surface area as high as ∼327 m(2)/g, and the resulting structures duplicate the shape of the original substrate. These hybrid films and porous materials could find uses in several research fields including gas separations and diffusion barriers, biomedical scaffolds, high surface area coatings, and others.

  20. An organic dye-polymer (phenol red-poly (vinyl alcohol)) composite architecture towards tunable -optical and -saturable absorption characteristics

    NASA Astrophysics Data System (ADS)

    Sreedhar, Sreeja; Illyaskutty, Navas; Sreedhanya, S.; Philip, Reji; Muneera, C. I.

    2016-05-01

    Herein, we demonstrate that blending an organic dye (guest/filler), with a vinyl polymer (host template), is an inexpensive and simple approach for the fabrication of multifunctional photonic materials which could display an enhancement in the desirable properties of the constituent materials and, at the same time provide novel synergistic properties for the guest-host system. A new guest-host nanocomposite system comprising Phenol Red dye and poly (vinyl alcohol) as guest and host template, respectively, which exhibits tunable optical characteristics and saturable absorption behavior, is introduced. The dependence of local electronic environment provided by the polymer template and the interactions of the polymer molecules with the encapsulated guest molecules on the observed optical/nonlinear absorption behavior is discussed. An understanding of the tunability of the optical/ photophysical processes, with respect to the filler content, as discussed herein could help in the design of improved optical materials for several photonic device applications like organic light emitting diodes and saturable absorbers.

  1. A shape tailored gold-conductive polymer nanocomposite as a transparent electrode with extraordinary insensitivity to volatile organic compounds (VOCs)

    NASA Astrophysics Data System (ADS)

    Khalil, Rania; Homaeigohar, Shahin; Häußler, Dietrich; Elbahri, Mady

    2016-09-01

    In this study, the transparent conducting polymer of poly (3,4-ethylenendioxythiophene): poly(styrene sulphonate) (PEDOT:PSS) was nanohybridized via inclusion of gold nanofillers including nanospheres (NSs) and nanorods (NRs). Such nanocomposite thin films offer not only more optimum conductivity than the pristine polymer but also excellent resistivity against volatile organic compounds (VOCs). Interestingly, such amazing properties are achieved in the diluted regimes of the nanofillers and depend on the characteristics of the interfacial region of the polymer and nanofillers, i.e. the aspect ratio of the latter component. Accordingly, a shape dependent response is made that is more desirable in case of using the Au nanorods with a much larger aspect ratio than their nanosphere counterparts. This transparent nanocomposite thin film with an optimized conductivity and very low sensitivity to organic gases is undoubtedly a promising candidate material for the touch screen panel production industry. Considering PEDOT as a known material for integrated electrodes in energy saving applications, we believe that our strategy might be an important progress in the field.

  2. A shape tailored gold-conductive polymer nanocomposite as a transparent electrode with extraordinary insensitivity to volatile organic compounds (VOCs)

    PubMed Central

    Khalil, Rania; Homaeigohar, Shahin; Häußler, Dietrich; Elbahri, Mady

    2016-01-01

    In this study, the transparent conducting polymer of poly (3,4-ethylenendioxythiophene): poly(styrene sulphonate) (PEDOT:PSS) was nanohybridized via inclusion of gold nanofillers including nanospheres (NSs) and nanorods (NRs). Such nanocomposite thin films offer not only more optimum conductivity than the pristine polymer but also excellent resistivity against volatile organic compounds (VOCs). Interestingly, such amazing properties are achieved in the diluted regimes of the nanofillers and depend on the characteristics of the interfacial region of the polymer and nanofillers, i.e. the aspect ratio of the latter component. Accordingly, a shape dependent response is made that is more desirable in case of using the Au nanorods with a much larger aspect ratio than their nanosphere counterparts. This transparent nanocomposite thin film with an optimized conductivity and very low sensitivity to organic gases is undoubtedly a promising candidate material for the touch screen panel production industry. Considering PEDOT as a known material for integrated electrodes in energy saving applications, we believe that our strategy might be an important progress in the field. PMID:27654345

  3. Solvent-vapour-assisted pathways and the role of pre-organization in solid-state transformations of coordination polymers

    PubMed Central

    Wright, James S.; Vitórica-Yrezábal, Iñigo J.; Adams, Harry; Thompson, Stephen P.; Hill, Adrian H.; Brammer, Lee

    2015-01-01

    A family of one-dimensional coordination polymers, [Ag4(O2C(CF2)2CF3)4(phenazine)2(arene)n]·m(arene), 1 (arene = toluene or xylene), have been synthesized and crystallographically characterized. Arene guest loss invokes structural transformations to yield a pair of polymorphic coordination polymers [Ag4(O2C(CF2)2CF3)4(phenazine)2], 2a and/or 2b, with one- and two-dimensional architectures, respectively. The role of pre-organization of the polymer chains of 1 in the selectivity for formation of either polymorph is explored, and the templating effect of toluene and p-xylene over o-xylene or m-xylene in the formation of arene-containing architecture 1 is also demonstrated. The formation of arene-free phase 2b, not accessible in a phase-pure form through other means, is shown to be the sole product of loss of toluene from 1-tol·tol [Ag4(O2C(CF2)2CF3)4(phenazine)2(toluene)]·2(toluene), a phase containing toluene coordinated to Ag(I) in an unusual μ:η1,η1 manner. Solvent-vapour-assisted conversion between the polymorphic coordination polymers and solvent-vapour influence on the conversion of coordination polymers 1 to 2a and 2b is also explored. The transformations have been examined and confirmed by X-ray diffraction, NMR spectroscopy and thermal analyses, including in situ diffraction studies of some transformations. PMID:25866656

  4. Co-assembly of Zn(SPh){sub 2} and organic linkers into helical and zig-zag polymer chains

    SciTech Connect

    Liu Yi; Yu Lingmin; Loo, Say Chye Joachim; Blair, Richard G.; Zhang Qichun

    2012-07-15

    Two novel one-dimensional coordination polymers, single helicate [Zn(SPh){sub 2}(TPyTA)(EG)]{sub n} (EG=ethylene glycol) (1) and zig-zag structure [Zn(SPh){sub 2}(BPyVB)]{sub n} (2), were synthesized under solvothermal conditions at 150 Degree-Sign C or room temperature by the co-assembly of Zn(SPh){sub 2} and organic linkers such as 2,4,6-tri(4-pyridyl)-1,3,5-triazine (TPyTA) and 1,3-bis(trans-4-pyridylvinyl)benzene (BPyVB). X-ray crystallography study reveals that both polymers 1 and 2 crystallize in space group P2{sub 1}/c of the monoclinic system. The solid-state UV-vis absorption spectra show that 1 and 2 have maxium absorption onsets at 400 nm and 420 nm, respectively. TGA analysis indicates that 1 and 2 are stable up to 110 Degree-Sign C and 210 Degree-Sign C. - Graphical abstract: Two novel one-dimensional coordination polymers, single helicate [Zn(SPh){sub 2}(TPyTA)(EG)]{sub n} (1) and zig-zag structure [Zn(SPh){sub 2}(BPyVB)]{sub n} (2), were synthesized. Solid-state UV-vis absorptions show that 1 and 2 have maxium absorption onsets at 400 nm and 420 nm, respectively. TGA analysis indicates that 1 and 2 are stable up to 110 Degree-Sign C and 210 Degree-Sign C. Highlights: Black-Right-Pointing-Pointer Two novel one-dimensional coordination polymers have been synthesized. Black-Right-Pointing-Pointer TPyTA results in helical structures in 1 while BPyVB leads to zig-zag chains in 2. Black-Right-Pointing-Pointer Solid-state UV-vis absorption spectra and TGA analysis of the title polymers were studied.

  5. Solvent-vapour-assisted pathways and the role of pre-organization in solid-state transformations of coordination polymers.

    PubMed

    Wright, James S; Vitórica-Yrezábal, Iñigo J; Adams, Harry; Thompson, Stephen P; Hill, Adrian H; Brammer, Lee

    2015-03-01

    A family of one-dimensional coordination polymers, [Ag4(O2C(CF2)2CF3)4(phenazine)2(arene) n ]·m(arene), 1 (arene = toluene or xylene), have been synthesized and crystallographically characterized. Arene guest loss invokes structural transformations to yield a pair of polymorphic coordination polymers [Ag4(O2C(CF2)2CF3)4(phenazine)2], 2a and/or 2b , with one- and two-dimensional architectures, respectively. The role of pre-organization of the polymer chains of 1 in the selectivity for formation of either polymorph is explored, and the templating effect of toluene and p-xylene over o-xylene or m-xylene in the formation of arene-containing architecture 1 is also demonstrated. The formation of arene-free phase 2b , not accessible in a phase-pure form through other means, is shown to be the sole product of loss of toluene from 1-tol·tol [Ag4(O2C(CF2)2CF3)4(phenazine)2(toluene)]·2(toluene), a phase containing toluene coordinated to Ag(I) in an unusual μ:η(1),η(1) manner. Solvent-vapour-assisted conversion between the polymorphic coordination polymers and solvent-vapour influence on the conversion of coordination polymers 1 to 2a and 2b is also explored. The transformations have been examined and confirmed by X-ray diffraction, NMR spectroscopy and thermal analyses, including in situ diffraction studies of some transformations. PMID:25866656

  6. Thermal Spray Formation of Polymer Coatings

    NASA Technical Reports Server (NTRS)

    Coquill, Scott; Galbraith, Stephen L.; Tuss. Darren L.; Ivosevic, Milan

    2008-01-01

    This innovation forms a sprayable polymer film using powdered precursor materials and an in-process heating method. This device directly applies a powdered polymer onto a substrate to form an adherent, mechanically-sound, and thickness-regulated film. The process can be used to lay down both fully dense and porous, e.g., foam, coatings. This system is field-deployable and includes power distribution, heater controls, polymer constituent material bins, flow controls, material transportation functions, and a thermal spray apparatus. The only thing required for operation in the field is a power source. Because this method does not require solvents, it does not release the toxic, volatile organic compounds of previous methods. Also, the sprayed polymer material is not degraded because this method does not use hot combustion gas or hot plasma gas. This keeps the polymer from becoming rough, porous, or poorly bonded.

  7. Dynamic Organization of Myristoylated Src in the Live Cell Plasma Membrane.

    PubMed

    Smith, Adam W; Huang, Hector H; Endres, Nicholas F; Rhodes, Christopher; Groves, Jay T

    2016-02-11

    The spatial organization of lipid-anchored proteins in the plasma membrane directly influences cell signaling, but measuring such organization in situ is experimentally challenging. The canonical oncogene, c-Src, is a lipid anchored protein that plays a key role in integrin-mediated signal transduction within focal adhesions and cell-cell junctions. Because of its activity in specific plasma membrane regions, structural motifs within the protein have been hypothesized to play an important role in its subcellular localization. This study used a combination of time-resolved fluorescence fluctuation spectroscopy and super-resolution microscopy to quantify the dynamic organization of c-Src in live cell membranes. Pulsed-interleaved excitation fluorescence cross-correlation spectroscopy (PIE-FCCS) showed that a small fraction of c-Src transiently sorts into membrane clusters that are several times larger than the monomers. Photoactivated localization microscopy (PALM) confirmed that c-Src partitions into clusters with low probability and showed that the characteristic size of the clusters is 10-80 nm. Finally, time-resolved fluorescence anisotropy measurements were used to quantify the rotational mobility of c-Src to determine how it interacts with its local environment. Taken together, these results build a quantitative description of the mobility and clustering behavior of the c-Src nonreceptor tyrosine kinase in the live cell plasma membrane. PMID:26771210

  8. Organic one-transistor-type nonvolatile memory gated with thin ionic liquid-polymer film for low voltage operation.

    PubMed

    Hwang, Sun Kak; Park, Tae Joon; Kim, Kang Lib; Cho, Suk Man; Jeong, Beom Jin; Park, Cheolmin

    2014-11-26

    As one of the most emerging next-generation nonvolatile memories, one-transistor (1T)-type nonvolatile memories are of great attention due to their excellent memory performance and simple device architecture suitable for high density memory arrays. In particular, organic 1T-type memories containing both organic semiconductors and insulators are further beneficial because of their mechanical flexibility with low cost fabrication. Here, we demonstrate a new flexible organic 1T-type memory operating at low voltage. The low voltage operation of a memory less than 10 V was obtained by employing a polymer gate insulator solution blended with ionic liquid as a charge storage layer. Ionic liquid homogeneously dissolved in a thin poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) film gave rise to low voltage operation of a device due to its high capacitance. Simultaneously, stable charge trapping of either anions or cations efficiently occurred in the polymer matrix, dependent upon gate bias. Optimization of ionic liquid in PVDF-TrFE thus led to an air-stable and mechanically flexible organic 1T-type nonvolatile memory operating at programming voltage of ±7 V with large ON/OFF current margin of approximately 10(3), reliable time-dependent data retention of more than 10(4) seconds, and write/read endurance cycles of 80.

  9. Assessment of a tannin-based organic polymer to harvest Chlorella vulgaris biomass from swine wastewater digestate phycoremediation.

    PubMed

    Mezzari, M P; da Silva, M L B; Pirolli, M; Perazzoli, S; Steinmetz, R L R; Nunes, E O; Soares, H M

    2014-01-01

    This study investigated the efficiency of an organic tannin polymer alone or amended with polyacrylamide to harvest Chlorella vulgaris biomass grown in a laboratory-scale photobioreactor treating swine wastewater digestate. The effect of biomass concentration, tannin (TAN) dosages and changes in pH were evaluated in jar test experiments. Among the TAN concentrations tested (11, 22, 44, 89, 178 mg L(-1)), 11 mg L(-1) showed the highest biomass recovery (97%). The highest coagulation/ flocculation efficiencies were obtained at pH 5 to 7. Flocculation efficiency improved from 50 to 97% concomitant with the increasing biomass concentrations from 45 to 165 mg L(-1), respectively. Recovery efficiencies above 95% were achieved with the same TAN dosage (11 mg L(-1)) irrespective of the concentration of organic carbon present (75 to 300 mg TOC L(-1)). Overall, the results suggest that TAN could become an interesting alternative choice of non-toxic organic polymer for harvesting Chlorella sp. from organic-rich wastewater. PMID:25225937

  10. Organic one-transistor-type nonvolatile memory gated with thin ionic liquid-polymer film for low voltage operation.

    PubMed

    Hwang, Sun Kak; Park, Tae Joon; Kim, Kang Lib; Cho, Suk Man; Jeong, Beom Jin; Park, Cheolmin

    2014-11-26

    As one of the most emerging next-generation nonvolatile memories, one-transistor (1T)-type nonvolatile memories are of great attention due to their excellent memory performance and simple device architecture suitable for high density memory arrays. In particular, organic 1T-type memories containing both organic semiconductors and insulators are further beneficial because of their mechanical flexibility with low cost fabrication. Here, we demonstrate a new flexible organic 1T-type memory operating at low voltage. The low voltage operation of a memory less than 10 V was obtained by employing a polymer gate insulator solution blended with ionic liquid as a charge storage layer. Ionic liquid homogeneously dissolved in a thin poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) film gave rise to low voltage operation of a device due to its high capacitance. Simultaneously, stable charge trapping of either anions or cations efficiently occurred in the polymer matrix, dependent upon gate bias. Optimization of ionic liquid in PVDF-TrFE thus led to an air-stable and mechanically flexible organic 1T-type nonvolatile memory operating at programming voltage of ±7 V with large ON/OFF current margin of approximately 10(3), reliable time-dependent data retention of more than 10(4) seconds, and write/read endurance cycles of 80. PMID:25341965

  11. Facile Carbonization of Microporous Organic Polymers into Hierarchically Porous Carbons Targeted for Effective CO2 Uptake at Low Pressures.

    PubMed

    Gu, Shuai; He, Jianqiao; Zhu, Yunlong; Wang, Zhiqiang; Chen, Dongyang; Yu, Guipeng; Pan, Chunyue; Guan, Jianguo; Tao, Kai

    2016-07-20

    The advent of microporous organic polymers (MOPs) has delivered great potential in gas storage and separation (CCS). However, the presence of only micropores in these polymers often imposes diffusion limitations, which has resulted in the low utilization of MOPs in CCS. Herein, facile chemical activation of the single microporous organic polymers (MOPs) resulted in a series of hierarchically porous carbons with hierarchically meso-microporous structures and high CO2 uptake capacities at low pressures. The MOPs precursors (termed as MOP-7-10) with a simple narrow micropore structure obtained in this work possess moderate apparent BET surface areas ranging from 479 to 819 m(2) g(-1). By comparing different activating agents for the carbonization of these MOPs matrials, we found the optimized carbon matrials MOPs-C activated by KOH show unique hierarchically porous structures with a significant expansion of dominant pore size from micropores to mesopores, whereas their microporosity is also significantly improved, which was evidenced by a significant increase in the micropore volume (from 0.27 to 0.68 cm(3) g(-1)). This maybe related to the collapse and the structural rearrangement of the polymer farmeworks resulted from the activation of the activating agent KOH at high temperature. The as-made hierarchically porous carbons MOPs-C show an obvious increase in the BET surface area (from 819 to 1824 m(2) g(-1)). And the unique hierarchically porous structures of MOPs-C significantly contributed to the enhancement of the CO2 capture capacities, which are up to 214 mg g(-1) (at 273 K and 1 bar) and 52 mg g(-1) (at 273 K and 0.15 bar), superior to those of the most known MOPs and porous carbons. The high physicochemical stabilities and appropriate isosteric adsorption heats as well as high CO2/N2 ideal selectivities endow these hierarchically porous carbon materials great potential in gas sorption and separation. PMID:27332739

  12. Facile Carbonization of Microporous Organic Polymers into Hierarchically Porous Carbons Targeted for Effective CO2 Uptake at Low Pressures.

    PubMed

    Gu, Shuai; He, Jianqiao; Zhu, Yunlong; Wang, Zhiqiang; Chen, Dongyang; Yu, Guipeng; Pan, Chunyue; Guan, Jianguo; Tao, Kai

    2016-07-20

    The advent of microporous organic polymers (MOPs) has delivered great potential in gas storage and separation (CCS). However, the presence of only micropores in these polymers often imposes diffusion limitations, which has resulted in the low utilization of MOPs in CCS. Herein, facile chemical activation of the single microporous organic polymers (MOPs) resulted in a series of hierarchically porous carbons with hierarchically meso-microporous structures and high CO2 uptake capacities at low pressures. The MOPs precursors (termed as MOP-7-10) with a simple narrow micropore structure obtained in this work possess moderate apparent BET surface areas ranging from 479 to 819 m(2) g(-1). By comparing different activating agents for the carbonization of these MOPs matrials, we found the optimized carbon matrials MOPs-C activated by KOH show unique hierarchically porous structures with a significant expansion of dominant pore size from micropores to mesopores, whereas their microporosity is also significantly improved, which was evidenced by a significant increase in the micropore volume (from 0.27 to 0.68 cm(3) g(-1)). This maybe related to the collapse and the structural rearrangement of the polymer farmeworks resulted from the activation of the activating agent KOH at high temperature. The as-made hierarchically porous carbons MOPs-C show an obvious increase in the BET surface area (from 819 to 1824 m(2) g(-1)). And the unique hierarchically porous structures of MOPs-C significantly contributed to the enhancement of the CO2 capture capacities, which are up to 214 mg g(-1) (at 273 K and 1 bar) and 52 mg g(-1) (at 273 K and 0.15 bar), superior to those of the most known MOPs and porous carbons. The high physicochemical stabilities and appropriate isosteric adsorption heats as well as high CO2/N2 ideal selectivities endow these hierarchically porous carbon materials great potential in gas sorption and separation.

  13. The Plasma Membrane Potential and the Organization of the Actin Cytoskeleton of Epithelial Cells

    PubMed Central

    Chifflet, Silvia; Hernández, Julio A.

    2012-01-01

    The establishment and maintenance of the polarized epithelial phenotype require a characteristic organization of the cytoskeletal components. There are many cellular effectors involved in the regulation of the cytoskeleton of epithelial cells. Recently, modifications in the plasma membrane potential (PMP) have been suggested to participate in the modulation of the cytoskeletal organization of epithelia. Here, we review evidence showing that changes in the PMP of diverse epithelial cells promote characteristic modifications in the cytoskeletal organization, with a focus on the actin cytoskeleton. The molecular paths mediating these effects may include voltage-sensitive integral membrane proteins and/or peripheral proteins sensitive to surface potentials. The voltage dependence of the cytoskeletal organization seems to have implications in several physiological processes, including epithelial wound healing and apoptosis. PMID:22315611

  14. Pattern formation and self-organization in plasmas interacting with surfaces

    NASA Astrophysics Data System (ADS)

    Trelles, Juan Pablo

    2016-10-01

    Pattern formation and self-organization are fascinating phenomena commonly observed in diverse types of biological, chemical and physical systems, including plasmas. These phenomena are often responsible for the occurrence of coherent structures found in nature, such as recirculation cells and spot arrangements; and their understanding and control can have important implications in technology, e.g. from determining the uniformity of plasma surface treatments to electrode erosion rates. This review comprises theoretical, computational and experimental investigations of the formation of spatiotemporal patterns that result from self-organization events due to the interaction of low-temperature plasmas in contact with confining or intervening surfaces, particularly electrodes. The basic definitions associated to pattern formation and self-organization are provided, as well as some of the characteristics of these phenomena within natural and technological contexts, especially those specific to plasmas. Phenomenological aspects of pattern formation include the competition between production/forcing and dissipation/transport processes, as well as nonequilibrium, stability, bifurcation and nonlinear interactions. The mathematical modeling of pattern formation in plasmas has encompassed from theoretical approaches and canonical models, such as reaction-diffusion systems, to drift-diffusion and nonequilibrium fluid flow models. The computational simulation of pattern formation phenomena imposes distinct challenges to numerical methods, such as high sensitivity to numerical approximations and the occurrence of multiple solutions. Representative experimental and numerical investigations of pattern formation and self-organization in diverse types of low-temperature electrical discharges (low and high pressure glow, dielectric barrier and arc discharges, etc) in contact with solid and liquid electrodes are reviewed. Notably, plasmas in contact with liquids, found in diverse

  15. The magnetocaloric effect with critical behavior of a periodic Anderson-like organic polymer.

    PubMed

    Ding, L J; Zhong, Y; Fan, S W; Zhu, L Y

    2016-01-01

    We study the magnetocaloric effect and the critical behavior of a periodic Anderson-like organic polymer using Green's function theory, in which the localized f orbitals hybridize with the conduction orbitals at even sites. The field-induced metal-insulator transitions with the magnetic Grüneisen parameter showing |Γh|∼T(-1) power-law critical behaviour are revealed, which provides a new thermodynamic means for probing quantum phase transitions. It is found that the competition of up-spin and down-spin hole excitations is responsible for the double peak structure of magnetic entropy change (-ΔS) for the dominant Kondo coupling case, implying a double magnetic cooling process via demagnetization, which follows a power law dependence of the magnetic field h: -ΔS∼h(n). The local exponent n tends to 1 and 2 below and above TC, while has a minimum of 0.648 at TC, which is in accordance with the experimental observation of perovskite manganites Pr0.55Sr0.45MnO3 and Nd0.55Sr0.45MnO3 (J. Y. Fan et al., Appl. Phys. Lett., 2011, 98, 072508; Europhys. Lett., 2015, 112, 17005) corresponding to the conventional ferromagnets within the mean field theory -ΔS∼h(2/3). At TC, the -ΔS∼h curves with a convex curvature superpose each other for small V values, which are separated by the large V case, distinguishing the RKKY interaction and Kondo coupling explicitly. Furthermore, the critical scaling law n(TC) = 1 + (β- 1)/(β + γ) = 1 + 1/δ(1 - 1/β) is related to the critical exponents (β, γ, and δ) extracted from the Arrott-Noakes equation of state and the Kouvel-Fisher method, which fulfill the Widom scaling relation δ = 1 + γβ(-1), indicating the self-consistency and reliability of the obtained results. In addition, based on the scaling hypothesis through checking the scaling analysis of magnetization, the M-T-h curves collapse into two independent universal branches below and above TC.

  16. The magnetocaloric effect with critical behavior of a periodic Anderson-like organic polymer.

    PubMed

    Ding, L J; Zhong, Y; Fan, S W; Zhu, L Y

    2016-01-01

    We study the magnetocaloric effect and the critical behavior of a periodic Anderson-like organic polymer using Green's function theory, in which the localized f orbitals hybridize with the conduction orbitals at even sites. The field-induced metal-insulator transitions with the magnetic Grüneisen parameter showing |Γh|∼T(-1) power-law critical behaviour are revealed, which provides a new thermodynamic means for probing quantum phase transitions. It is found that the competition of up-spin and down-spin hole excitations is responsible for the double peak structure of magnetic entropy change (-ΔS) for the dominant Kondo coupling case, implying a double magnetic cooling process via demagnetization, which follows a power law dependence of the magnetic field h: -ΔS∼h(n). The local exponent n tends to 1 and 2 below and above TC, while has a minimum of 0.648 at TC, which is in accordance with the experimental observation of perovskite manganites Pr0.55Sr0.45MnO3 and Nd0.55Sr0.45MnO3 (J. Y. Fan et al., Appl. Phys. Lett., 2011, 98, 072508; Europhys. Lett., 2015, 112, 17005) corresponding to the conventional ferromagnets within the mean field theory -ΔS∼h(2/3). At TC, the -ΔS∼h curves with a convex curvature superpose each other for small V values, which are separated by the large V case, distinguishing the RKKY interaction and Kondo coupling explicitly. Furthermore, the critical scaling law n(TC) = 1 + (β- 1)/(β + γ) = 1 + 1/δ(1 - 1/β) is related to the critical exponents (β, γ, and δ) extracted from the Arrott-Noakes equation of state and the Kouvel-Fisher method, which fulfill the Widom scaling relation δ = 1 + γβ(-1), indicating the self-consistency and reliability of the obtained results. In addition, based on the scaling hypothesis through checking the scaling analysis of magnetization, the M-T-h curves collapse into two independent universal branches below and above TC. PMID:26617276

  17. Room temperature synthesis of a Zn(II) metal-organic coordination polymer for dye removal

    NASA Astrophysics Data System (ADS)

    Abbasi, Alireza; Gharib, Maniya; Najafi, Mahnaz; Janczak, Jan

    2016-03-01

    A new one-dimensional (1D) coordination polymer, [Zn(4,4‧-bpy)(H2O)4](ADC)·4H2O (1) (4,4‧-bpy=4,4‧-bipyridine and H2ADC=acetylenedicarboxylic acid), was synthesized at room temperature. The crystal structure of the coordination polymer was determined by single-crystal X-ray diffraction analysis. Compound 1 was also characterized by FT-IR, powder X-ray diffraction (PXRD) and thermogravimetric analysis (TGA). The catalytic activity of 1 was evaluated in the color removal of Bismarck brown as a representative of dye pollutant in water under mild conditions. Coordination polymer 1 exhibited good catalytic activity and stability in the decolorization of Bismarck brown and could be easily recovered and reused for at least three cycles.

  18. Understanding Polymer-Fullerene Morphology in Organic Solar Cells via Photoluminescence, Raman Scattering, and Spectroscopic Imaging

    NASA Astrophysics Data System (ADS)

    Carach, Christopher Andrew

    Understanding and controlling carrier transport in conjugated polymer films and composites is critical to the development and application of plastic solar cells. Recent efforts have focused on "bulk heterojunction" structures where a conjugated polymer donor is mixed at the nanoscale with a fullerene acceptor to achieve large interfacial areas for exciton splitting. In these systems, fabrication protocols dramatically affect device efficiency and charge transport is intimately tied to film morphology through local order, domain formation, and compositional heterogeneity. We employ both far-field and confocal/near-field optical spectroscopy (absorbance, low-temperature photoluminescence, Raman) to study chain order (aggregation, pi-stacking), photo-oxidation, and local morphology in conjugated polymer (PPV and polythiophene) -- fullerene (PCBM) blends. Through quantitative analysis of exciton bandwidths, emission intensity, and vibronic lineshapes, we demonstrate that competition exists between the chemical "disordering" effect of photo-degradation and the physical "ordering" effect of aggregation, each of which dominate under different processing conditions. Large changes in photoluminescence and Raman show that PCBM begins to significantly hinder intra-chain planarization and inter-chain pi-overlap at a critical PCBM weight fraction. Furthermore, the critical weight fraction is a function of the polymer regiochemistry, occurring at lower PCBM weight fractions for a more regio-random polymer. Mild thermal annealing of blended films was seen to restore order, which results from PCBM phase segregation (lower dispersion) and growth of polymer aggregates. Spatially resolved spectral analysis of photoluminescence was also used to map fullerene diffusion and agglomeration as well as detect local changes in interfacial contact between donor and acceptor domains due to thermal annealing.

  19. .pi.-conjugated heavy-metal polymers for organic white-light-emitting diodes

    DOEpatents

    Vardeny, Zeev Valentine; Wojcik, Leonard; Drori, Tomer

    2016-09-13

    A polymer mixture emits a broad spectrum of visible light that appears white or near-white in the aggregate. The polymer mixture comprises two (or more) components in the active layer. A heavy atom, such as platinum and/or iridium, present in the backbone of the mixture acts via a spin-orbit coupling mechanism to cause the ratio of fluorescent to phosphorescent light emission bands to be of approximately equal strength. These two broad emissions overlap, resulting in an emission spectrum that appears to the eye to be white.

  20. Organization of tethered polyoxazoline polymer brushes at the air/water interface

    NASA Astrophysics Data System (ADS)

    Gutberlet, T.; Wurlitzer, A.; Dietrich, U.; Politsch, E.; Cevc, G.; Steitz, R.; Lösche, M.

    2000-06-01

    Surface monolayers of short chain poly(methyl oxazoline) (PMeOx) attached to diacylglycerol have been investigated by X-ray and neutron reflectivity in pure systems and in binary mixtures with the unmodified phospholipid DMPC at the air/water interface. Reflectivity curves of pure PMeOx and its mixtures with DMPC indicate an extended conformation of the polymer independent of the available lateral area and pressure. An almost linear increase in the thickness of the polymer layer is found with increasing lateral pressure π. The thickness of the hydrophobic slab within the surface monolayers decreases continuously upon addition of PMeOx to DMPC.

  1. Functionalization of alkyne-terminated thermally hydrocarbonized porous silicon nanoparticles with targeting peptides and antifouling polymers: effect on the human plasma protein adsorption.

    PubMed

    Wang, Chang-Fang; Mäkilä, Ermei M; Bonduelle, Colin; Rytkönen, Jussi; Raula, Janne; Almeida, Sérgio; Närvänen, Ale; Salonen, Jarno J; Lecommandoux, Sebastien; Hirvonen, Jouni T; Santos, Hélder A

    2015-01-28

    Porous silicon (PSi) nanomaterials combine a high drug loading capacity and tunable surface chemistry with various surface modifications to meet the requirements for biomedical applications. In this work, alkyne-terminated thermally hydrocarbonized porous silicon (THCPSi) nanoparticles were fabricated and postmodified using five bioactive molecules (targeting peptides and antifouling polymers) via a single-step click chemistry to modulate the bioactivity of the THCPSi nanoparticles, such as enhancing the cellular uptake and reducing the plasma protein association. The size of the nanoparticles after modification was increased from 176 to 180-220 nm. Dextran 40 kDa modified THCPSi nanoparticles showed the highest stability in aqueous buffer. Both peptide- and polymer-functionalized THCPSi nanoparticles showed an extensive cellular uptake which was dependent on the functionalized moieties presented on the surface of the nanoparticles. The plasma protein adsorption study showed that the surface modification with different peptides or polymers induced different protein association profiles. Dextran 40 kDa functionalized THCPSi nanoparticles presented the least protein association. Overall, these results demonstrate that the "click" conjugation of the biomolecules onto the alkyne-terminated THCPSi nanoparticles is a versatile and simple approach to modulate the surface chemistry, which has high potential for biomedical applications.

  2. Revelation of intertwining organic and inorganic fractal structures in polymer coatings.

    PubMed

    Hughes, A E; Trinchi, A; Chen, F F; Yang, Y S; Cole, I S; Sellaiyan, S; Carr, J; Lee, P D; Thompson, G E; Xiao, T Q

    2014-07-01

    X-ray microtomography and serial block face scanning electron microscopy are used to reveal independent clusters of inorganic particles embedded within a polymer. These clusters are interpenetrating, of varying size, and have fractal dimensions that strongly influence transport and structure-property relations. This interpretation forms a baseline for designing hybrid materials for applications in self-healing, drug delivery, and membranes.

  3. Broadband energy-efficient optical modulation by hybrid integration of silicon nanophotonics and organic electro-optic polymer

    NASA Astrophysics Data System (ADS)

    Zhang, Xingyu; Hosseini, Amir; Subbaraman, Harish; Luo, Jingdong; Jen, Alex K.-Y.; Chung, Chi-jui; Yan, Hai; Pan, Zeyu; Nelson, Robert L.; Chen, Ray T.

    2015-03-01

    Silicon-organic hybrid integrated devices have emerging applications ranging from high-speed optical interconnects to photonic electromagnetic-field sensors. Silicon slot photonic crystal waveguides (PCWs) filled with electro-optic (EO) polymers combine the slow-light effect in PCWs with the high polarizability of EO polymers, which promises the realization of high-performance optical modulators. In this paper, a broadband, power-efficient, low-dispersion, and compact optical modulator based on an EO polymer filled silicon slot PCW is presented. A small voltage-length product of Vπ×L=0.282V×mm is achieved, corresponding to an unprecedented record-high effective in-device EO coefficient (r33) of 1230pm/V. Assisted by a backside gate voltage, the modulation response up to 50GHz is observed, with a 3-dB bandwidth of 15GHz, and the estimated energy consumption is 94.4fJ/bit at 10Gbit/s. Furthermore, lattice-shifted PCWs are utilized to enhance the optical bandwidth by a factor of ~10X over other modulators based on non-band-engineered PCWs and ring-resonators.

  4. Influence of natural organic matter on transport and retention of polymer coated silver nanoparticles in porous media.

    PubMed

    Yang, Xinyao; Lin, Shihong; Wiesner, Mark R

    2014-01-15

    Interactions between organic matter (OM) and engineered polymer coatings as they affect the retention of polyvinylpyrrolidone (PVP) polymer-coated silver nanoparticles (AgNPs) were studied. Two distinct types of OM-cysteine representing low molecular weight multivalent functional groups, and Suwannee River Humic Acid (HA) representing high molecular weight polymers, were investigated with respect to their effects on particle stability in aggregation and deposition. Aggregation of the PVP coated AgNPs (PVP-AgNPs) was enhanced by cysteine addition at high ionic strengths, which was attributed to cysteine binding to the AgNPs and replacing the otherwise steric stabilizing agent PVP. In contrast the addition of HA did not increase aggregation rates and decreased PVP-AgNP deposition to the silica porous medium, consistent with enhanced electrosteric stabilization by the HA. Although cysteine also reduced deposition in the porous medium, the mechanisms of reduced deposition appear to be enhanced electric double layer (EDL) interaction at low ionic strengths. At higher ionic strengths, aggregation was favored leading to lower deposition due to smaller diffusion coefficients and single collector efficiencies despite the reduced EDL interactions. PMID:24295767

  5. Air-stable solution-processed n-channel organic thin film transistors with polymer-enhanced morphology

    SciTech Connect

    He, Zhengran; Shaik, Shoieb; Bi, Sheng; Li, Dawen; Chen, Jihua

    2015-05-04

    N,N′-1H,1H-perfluorobutyl dicyanoperylenecarboxydiimide (PDIF-CN{sub 2}) is an n-type semiconductor exhibiting high electron mobility and excellent air stability. However, the reported electron mobility based on spin-coated PDIF-CN{sub 2} film is much lower than the value of PDIF-CN{sub 2} single crystals made from vapor phase deposition, indicating significant room for mobility enhancement. In this study, various insulating polymers, including poly(vinyl alcohol), poly(methyl methacrylate) (PMMA), and poly(alpha-methylstyrene) (PαMS), are pre-coated on silicon substrate aiming to enhance the morphology of the PDIF-CN{sub 2} thin film, thereby improving the charge transport and air stability. Atomic force microscopy images reveal that with the pre-deposition of PαMS or PMMA polymers, the morphology of the PDIF-CN{sub 2} polycrystalline films is optimized in semiconducting crystal connectivity, domain size, and surface roughness, which leads to significant improvement of organic thin-film transistor (OTFT) performance. Particularly, an electron mobility of up to 0.55 cm{sup 2}/V s has been achieved from OTFTs based on the PDIF-CN{sub 2} film with the pre-deposition of PαMS polymer.

  6. Correlation to Predict Collision Efficiency of Natural Organic Matter (NOM)- and Polymer- coated Nanoparticles in Porous Media

    NASA Astrophysics Data System (ADS)

    Lowry, G. V.; Phenrat, T.; Cisneros, C. M.; Schoenfelder, D. P.; Fagerlund, F.; Kim, H.; Illangasekare, T.; Tilton, R. D.

    2008-12-01

    The fate of manufactured nanoparticles released to the environment is of great interest due to their increasing use in consumer products and their potential risk to the environment and human health. Manufactured nanomaterials typically have a polymeric surface coating to provide specific functionality, or will adsorb natural organic matter (NOM) once released into the environment. Adsorbed polymer and NOM can provide electrosteic repulsions that enhance the migration of nanoparticles in porous media. Semi-empirical correlations to predict the collision efficiency of electrostatically stabilized (uncoated) colloids are available, however, they are not applicable to nanomaterials coated with polymeric or NOM layers. We present a semi- empirical correlation to predict the collision efficiency of NOM and polymer-coated nanomaterials in saturated porous media. The adsorbed mass and adsorbed layer properties (including thickness) are determined and particle breakthrough curves are generated for a number of particle and coating types. Regression analysis is then used to develop a semi-empirical correlation that includes a parameter (NLEK) representing electrosteric repulsions afforded by adsorbed NOM or polymer. The correlation appears robust over a range of four particle and four coating types and should be a valuable tool for predicting the relative mobility of different manufactured and natural nanomaterials based on a few measurable properties.

  7. Aerosol synthesis of self-organized nanostructured hollow and porous carbon particles using a dual polymer system.

    PubMed

    Balgis, Ratna; Ogi, Takashi; Wang, Wei-Ning; Anilkumar, Gopinathan M; Sago, Sumihito; Okuyama, Kikuo

    2014-09-30

    A facile method for designing and synthesizing nanostructured carbon particles via ultrasonic spray pyrolysis of a self-organized dual polymer system comprising phenolic resin and charged polystyrene latex is reported. The method produces either hollow carbon particles, whose CO2 adsorption capacity is 3.0 mmol g(-1), or porous carbon particles whose CO2 adsorption capacity is 4.8 mmol g(-1), although the two particle types had similar diameters of about 360 nm. We investigate how the zeta potential of the polystyrene latex particles, and the resulting electrostatic interaction with the negatively charged phenolic resin, influences the particle morphology, pore structure, and CO2 adsorption capacity. PMID:25211031

  8. Isostructural 1D coordination polymers of Zn(II), Cd(II) and Cu(II) with phenylpropynoic acid and DABCO as organic linkers

    NASA Astrophysics Data System (ADS)

    Saravanakumar, Rajendran; Varghese, Babu; Sankararaman, Sethuraman

    2014-11-01

    Using phenylpropynoic acid (PPA) and 1,4-diazabicyclo[2.2.2]octane (DABCO) as organic spacers, isostructural coordination polymers of Zn(II), Cd(II) and Cu(II) were synthesized by solvothermal method and structurally characterized using single crystal XRD, powder XRD, 13C CP-MAS NMR spectroscopy. Single crystal XRD data revealed four PPA units coordinating with two metal ions forming a paddle wheel secondary building unit (SBU). The paddle wheel units are connected through coordination of DABCO nitrogen to the metal centers from the axial positions leading to the formation of the 1D coordination polymers along the c axis. Intermolecular π stacking and Csbnd H…π interactions between the adjacent polymer chains convert the 1D coordination polymer into an interesting 3D network with the Csbnd H…π bonds running along the crystallographic a and b axes. Thermal and nitrogen adsorption studies of these coordination polymers are reported.

  9. Flash pyrolysis of hydroxyl-terminated polybutadiene (HTPB). 2: Implications of the kinetics to combustion of organic polymers

    SciTech Connect

    Arisawa, H.; Brill, T.B.

    1996-07-01

    The first semi-micro kinetics analysis is described for rapid pyrolysis of an organic polymer. T-Jump/FTIR spectroscopy and structurally different hydroxyl-terminated polybutadiene polymers (HTPB) were used. The rates of formation were determined for the six most prevalent volatile products from HTPB heated at 600 C/s to constant temperatures in the 450--609 C range under 2 and 11 atm of applied pressure. The resulting Arrhenius parameters reveal that mildly exothermic, bulk-phase, heterogeneous decomposition reactions control the rate of gaseous product evolution at T < 500--530 C under 2 atm Ar. The exact temperature depends on the product and the polymer microstructure. The rate evolution of most of the gaseous products at T > 500--530 C is controlled by desorption of fragments of the polymer rather than bulk-phase decomposition. When P = 11 atm Ar, the formation and desorption of these fragments controls the rate of product of evolution over the entire 460--600 C range. These individual rate constants combined into a single rate yield macro kinetics of gas evolution from R45M as follows: E{sub a} = 51 kcal/mol, ln A (s{sup {minus}1}) = 31 for 2 atm and 450--530 C; E{sub a} = 18 kcal/mol, ln A (S{sup {minus}1}) = 11 for 2 atm and 530--609 C; E{sub a} = 12 kcal/mol, ln A (s{sup {minus}1}) = 6.6 for 11 atm and 460--600 C. A generalized equation that qualitatively matches the kinetics of gaseous product evolution as a function of pressure is given.

  10. Modeling of plasma-induced self-healing in organic dielectrics

    NASA Astrophysics Data System (ADS)

    Kammermaier, J.; Rittmayer, G.; Birkle, S.

    1989-08-01

    Plasma-induced self-healing in organic dielectrics, which is of extremely great importance for capacitor technology, is dependent, in a complicated manner, upon electrical and physicochemical processes, which cannot be determined by metrology. Accordingly, a theoretical model was developed which describes the spatiotemporal distribution of potential and current in the plasma of a self-healing breakdown, the formation of gas as a consequence of decomposition of material, and the consequent graphite deposition in the insulating areas. In this way it is also possible to compute the insulating areas as well as the entire gas formation as a function of voltage, capacitance, and thickness of the metal electrodes, and the limits for reliable self-healing.

  11. Measurement and Comparison of Organic Compound Concentrations in Plasma, Whole Blood, and Dried Blood Spot Samples

    PubMed Central

    Batterman, Stuart A.; Chernyak, Sergey; Su, Feng-Chiao

    2016-01-01

    The preferred sampling medium for measuring human exposures of persistent organic compounds (POPs) is blood, and relevant sample types include whole blood, plasma, and dried blood spots (DBS). Because information regarding the performance and comparability of measurements across these sample types is limited, it is difficult to compare across studies. This study evaluates the performance of POP measurements in plasma, whole blood and DBS, and presents the distribution coefficients needed to convert concentrations among the three sample types. Blood samples were collected from adult volunteers, along with demographic and smoking information, and analyzed by GC/MS for organochlorine pesticides (OCPs), chlorinated hydrocarbons (CHCs), polychlorinated biphenyls (PCBs), and brominated diphenyl ethers (PBDEs). Regression models were used to evaluate the relationships between the sample types and possible effects of personal covariates. Distribution coefficients also were calculated using physically-based models. Across all compounds, concentrations in plasma were consistently the highest; concentrations in whole blood and DBS samples were comparable. Distribution coefficients for plasma to whole blood concentrations ranged from 1.74 to 2.26 for pesticides/CHCs, averaged 1.69 ± 0.06 for the PCBs, and averaged 1.65 ± 0.03 for the PBDEs. Regression models closely fit most chemicals (R2 > 0.80), and whole blood and DBS samples generally showed very good agreement. Distribution coefficients estimated using biologically-based models were near one and did not explain the observed distribution. Among the study population, median concentrations of several pesticides/CHCs and PBDEs exceeded levels reported in the 2007–2008 National Health and Nutrition Examination Survey, while levels of other OCPs and PBDEs were comparable or lower. Race and smoking status appeared to slightly affect plasma/blood concentration ratios for several POPs. The experimentally

  12. Laser Fabrication of Polymer Ferroelectric Nanostructures for Nonvolatile Organic Memory Devices.

    PubMed

    Martínez-Tong, Daniel E; Rodríguez-Rodríguez, Álvaro; Nogales, Aurora; García-Gutiérrez, Mari-Cruz; Pérez-Murano, Francesc; Llobet, Jordi; Ezquerra, Tiberio A; Rebollar, Esther

    2015-09-01

    Polymer ferroelectric laser-induced periodic surface structures (LIPSS) have been prepared on ferroelectric thin films of a poly(vinylidene fluoride-trifluoroethylene) copolymer. Although this copolymer does not absorb light at the laser wavelength, LIPSS on the copolymer can be obtained by forming a bilayer with other light-absorbing polymers. The ferroelectric nature of the structured bilayer was proven by piezoresponse force microscopy measurements. Ferroelectric hysteresis was found on both the bilayer and the laser-structured bilayer. We show that it is possible to write ferroelectric information at the nanoscale. The laser-structured ferroelectric bilayer showed an increase in the information storage density of an order of magnitude, in comparison to the original bilayer.

  13. Surface-Engineered Graphene Quantum Dots Incorporated into Polymer Layers for High Performance Organic Photovoltaics

    PubMed Central

    Kim, Jung Kyu; Kim, Sang Jin; Park, Myung Jin; Bae, Sukang; Cho, Sung-Pyo; Du, Qing Guo; Wang, Dong Hwan; Park, Jong Hyeok; Hong, Byung Hee

    2015-01-01

    Graphene quantum dots (GQDs), a newly emerging 0-dimensional graphene based material, have been widely exploited in optoelectronic devices due to their tunable optical and electronic properties depending on their functional groups. Moreover, the dispersibility of GQDs in common solvents depending on hydrophobicity or hydrophilicity can be controlled by chemical functionalization, which is particularly important for homogeneous incorporation into various polymer layers. Here we report that a surface-engineered GQD-incorporated polymer photovoltaic device shows enhanced power conversion efficiency (PCE), where the oxygen-related functionalization of GQDs enabled good dispersity in a PEDOT:PSS hole extraction layer, leading to significantly improved short circuit current density (Jsc) value. To maximize the PCE of the device, hydrophobic GQDs that are hydrothermally reduced (rGQD) were additionally incorporated in a bulk-heterojunction layer, which is found to promote a synergistic effect with the GQD-incorporated hole extraction layer. PMID:26392211

  14. Highly stereoselective, uniformly sized molecularly imprinted polymers for cinchona alkaloids in hydro-organic mobile phases.

    PubMed

    Haginaka, Jun; Kagawa, Chino

    2003-01-01

    Highly stereoselective, uniformly sized molecularly imprinted polymers (MIPs) for cinchona alkaloids, cinchonine (CN) and cinchonidine (CD), were prepared using methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylate (EDMA) as a cross-linker. The MIPs were evaluated using a mixture of phosphate buffer and acetonitrile as the mobile phase. The CN- and CD-imprinted MAA-co-EDMA polymers can recognize the respective template molecule more than the other diastereomer, and afford an excellent diastereomer separation of CN and CD. In addition, the MIPs gave diastereomer separations of structurally related compounds, quinidine and quinine. The retentive and stereoselective properties of those compounds on the MIPs suggest that electrostatic and hydrophobic interactions can work to recognize these compounds. Furthermore, thermodynamic studies reveal that the entropy-driven effect is significant at mobile-phase pH 5.4, while the enthalpy-driven interactions seem to be dominant at mobile-phase pH 9.6.

  15. Sampling for organic chemicals in workplace atmospheres with porous polymer beads.

    PubMed

    Dietrich, M W; Chapman, L M; Mieure, J P

    1978-05-01

    Porous polymer bead collection columns are frequently used in air pollution measurements. They are also useful for industrial hygiene applications when used with miniature personal pumps. Analytical procedures using this type of collection column are described which use thermal desorption for sample recovery followed by GC or GC/MS analysis. A means is shown to modify a gas chromatograph for this type of analysis. A technique which permits splitting of the collected sample is also described. Precision and accuracy data for recovery of nineteen chemicals are presented. Advantages of porous polymer bead procedures include high sensitivity (the total collected sample is analyzed), ease of sample handling and ability to analyze polar materials not recoverable from charcoal.

  16. A novel structural Fenton-like nanocatalyst with highly improved catalytic performance for generalized preparation of iron oxide@organic dye polymer core-shell nanospheres.

    PubMed

    Zhao, Guanghui; Peng, Xiaomen; Li, Hongping; Wang, Jianzhi; Zhou, Lincheng; Zhao, Tianqi; Huang, Zhihao; Jiang, Haifei

    2015-05-01

    FexOy@FexOy/C nanoparticles with a soap-bubble-like shell have been synthesized, and the materials exhibit excellent Fenton catalytic performance. More importantly, FexOy@FexOy/C nanoparticles as catalysts and precursors could catalyze organic dye molecules to form iron oxide@organic dye polymer core-shell nanospheres.

  17. A novel structural Fenton-like nanocatalyst with highly improved catalytic performance for generalized preparation of iron oxide@organic dye polymer core-shell nanospheres.

    PubMed

    Zhao, Guanghui; Peng, Xiaomen; Li, Hongping; Wang, Jianzhi; Zhou, Lincheng; Zhao, Tianqi; Huang, Zhihao; Jiang, Haifei

    2015-05-01

    FexOy@FexOy/C nanoparticles with a soap-bubble-like shell have been synthesized, and the materials exhibit excellent Fenton catalytic performance. More importantly, FexOy@FexOy/C nanoparticles as catalysts and precursors could catalyze organic dye molecules to form iron oxide@organic dye polymer core-shell nanospheres. PMID:25828271

  18. Development of a silver/polymer nanocomposite interconnection layer for organic tandem solar cells

    NASA Astrophysics Data System (ADS)

    Torabi, Naeimeh; Behjat, Abbas; Shahpari, Mahboobeh; Edalati, Shadi

    2015-01-01

    Interconnecting layers (ICL) play an important role in regulating the performance of tandem devices. We report the design of a solution-processed ICL that consists of a silver/polymer nanocomposite deposited on the top of a TiO2 layer. This nanocomposite contains modified poly (3,4-ethylenedioxythiophene) polystyrene sulfonic acid (PEDOT:PSS), and silver nanoparticles (Ag NPs) synthesized by the chemical reduction of silver nitrate in the presence of PEDOT:PSS. Formation of Ag NPs was confirmed by monitoring the plasmon absorption peak characteristics in the UV-visible spectrum of the synthesized nanocomposite. Transmission electron microscopy analysis indicated the presence of spherical silver NPs in a polymer matrix with a mean size of around 20 nm. The sheet resistance of PEDOT:PSS was found to be 2474±35 Ω/sq. It was changed to 445±28 Ω/sq after solvent modification and decreased to 53.31±3.59 Ω/sq after synthesizing silver NPs in the polymer medium. Meanwhile, the transparency of the nanocomposite film deposited on TiO2 was 89.6%, which is considered appropriate for an interconnecting electrode. We demonstrated that by incorporating a silver/polymer nanocomposite as a hole-transporting layer in contact with TiO2 as an electron-transporting layer, the ohmic behavior of ICL is enhanced with respect to pristine PEDOT:PSS. P3HT:PCBM-based tandem solar cells based on this solution-processed intermediate electrode represent significantly increased open-circuit voltage (Voc), reaching close to the sum of the single cells. By incorporating the nanocomposite in the tandem structure, a Voc of 1.1 V was obtained. This value was almost the sum of the Voc of two single cells, which was 1.18 V.

  19. Reduced bleaching in organic nanofibers by bilayer polymer/oxide coating

    SciTech Connect

    Tavares, L.; Kjelstrup-Hansen, J.; Rubahn, H.-G.; Sturm, H.

    2010-05-15

    Para-hexaphenylene (p-6P) molecules exhibit a characteristic photoinduced reaction (bleaching) resulting in a decrease in luminescence intensity upon UV light exposure, which could render the technological use of the nanofibers problematic. In order to investigate the photoinduced reaction in nanofibers, optical bleaching experiments have been performed by irradiating both pristine and coated nanofibers with UV light. Oxide coating materials (SiO{sub x} and Al{sub 2}O{sub 3}) were applied onto p-6P nanofibers. These treatments caused a reduction in the bleaching reaction but in addition, the nanofiber luminescence spectrum was significantly altered. It was observed that some polymer coatings [a statistical copolymer of tetrafluoroethylene and 2,2-bis-trifluoromethyl-4,5-difluoro-1,3-dioxole, P(TFE-PDD), and poly(methyl methacrylate), PMMA] do not interfere with the luminescence spectrum from the p-6P but are not effective in stopping the bleaching. Bilayer coatings with first a polymer material, which should work as a protection layer to avoid modifications of the p-6P luminescence spectrum, and second an oxide layer used as oxygen blocker were tested and it was found that a particular bilayer polymer/oxide combination results in a significant reduction in bleaching without affecting significantly the emission spectrum from the nanofibers.

  20. Reduced bleaching in organic nanofibers by bilayer polymer/oxide coating

    NASA Astrophysics Data System (ADS)

    Tavares, L.; Kjelstrup-Hansen, J.; Rubahn, H.-G.; Sturm, H.

    2010-05-01

    Para-hexaphenylene (p-6P) molecules exhibit a characteristic photoinduced reaction (bleaching) resulting in a decrease in luminescence intensity upon UV light exposure, which could render the technological use of the nanofibers problematic. In order to investigate the photoinduced reaction in nanofibers, optical bleaching experiments have been performed by irradiating both pristine and coated nanofibers with UV light. Oxide coating materials (SiOx and Al2O3) were applied onto p-6P nanofibers. These treatments caused a reduction in the bleaching reaction but in addition, the nanofiber luminescence spectrum was significantly altered. It was observed that some polymer coatings [a statistical copolymer of tetrafluoroethylene and 2,2-bis-trifluoromethyl-4,5-difluoro-1,3-dioxole, P(TFE-PDD), and poly(methyl methacrylate), PMMA] do not interfere with the luminescence spectrum from the p-6P but are not effective in stopping the bleaching. Bilayer coatings with first a polymer material, which should work as a protection layer to avoid modifications of the p-6P luminescence spectrum, and second an oxide layer used as oxygen blocker were tested and it was found that a particular bilayer polymer/oxide combination results in a significant reduction in bleaching without affecting significantly the emission spectrum from the nanofibers.