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Sample records for organic plasma polymer

  1. Preparation and characterization of beryllium doped organic plasma polymer coatings

    SciTech Connect

    Brusasco, R.; Letts, S.; Miller, P.; Saculla, M.; Cook, R.

    1995-10-04

    We report the formation of beryllium doped plasma polymerized coatings derived from a helical resonator deposition apparatus, using diethylberyllium as the organometaric source. These coatings had an appearance not unlike plain plasma polymer and were relatively stable to ambient exposure. The coatings were characterized by Inductively Coupled Plasma Mass Spectrometry and X-Ray Photoelectron Spectroscopy. Coating rates approaching 0.7 {mu}m hr{sup {minus}1} were obtained with a beryllium-to-carbon ratio of 1:1.3. There is also a significant oxygen presence in the coating as well which is attributed to oxidation upon exposure of the coating to air. The XPS data show only one peak for beryllium with the preponderance of the XPS data suggesting that the beryllium exists as BeO. Diethylberyllium was found to be inadequate as a source for beryllium doped plasma polymer, due to thermal decomposition and low vapor recovery rates.

  2. 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.

  3. 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.

  4. 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.

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

    NASA Astrophysics Data System (ADS)

    Kurihara, Kazuaki; Egami, Akihiro; Nakamura, Moritaka

    2005-10-01

    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 N2 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 N2 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 H2 plasmas, EY scarcely depended on the ion energy regardless of the polymers. Etching behaviors with Ar and H2 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, H2, and N2 plasmas.

  6. 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

    2013-10-03

    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.

  7. Etching Characteristics of Organic Polymers in the Magnetic Neutral Loop Discharge Plasma

    NASA Astrophysics Data System (ADS)

    Morikawa, Yasuhiro; Hayashi, Toshio; Uchida, Taijiro

    2003-03-01

    Etchings of organic low-k materials, FLARE, SiLK and polyimide films were carried out in a N2-dominant mixed gas plasma generated by a magnetic neutral loop discharge (NLD) method at a low pressure below 1 Pa. The results showed that the uppermost layers on the top surface and sidewall surface were composed of tightly bonded C-N \\mathit{sp}3, so anisotropic profiles were obtained in the case of the N2-dominant mixture ratio of the N2 + H2 plasma. Based on this result, we also investigated polyimide deep etching under the same condition, and successfully obtained an anisotropic etched profile with the depth of about 8 μm and the linewidth of about 0.5 μm (aspect ratio of 16).

  8. 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.

  9. 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.

  10. Chamber For Testing Polymers In Oxygen Plasma

    NASA Technical Reports Server (NTRS)

    Whitaker, Ann F.

    1990-01-01

    Apparatus holds polymer specimen at constant temperature while exposing it to oxygen plasma. Copper tube (part of cooling coil) extends into plasma chamber, supporting copper block and thermoelectric module on which specimen mounted. Copper block made small - 4.4 by 3.8 by 1.6 cm - having little effect on plasma. Used to evaluate resistances of polymer materials to plasma environments, and for analysis of gases produced by attack of plasma on polymer specimen.

  11. Improvement of device performance of polymer organic light-emitting diodes on smooth transparent sheet with graphene films synthesized by plasma treatment

    NASA Astrophysics Data System (ADS)

    Okigawa, Yuki; Mizutani, Wataru; Suzuki, Kenkichi; Ishihara, Masatou; Yamada, Takatoshi; Hasegawa, Masataka

    2015-09-01

    Because graphene films have one-atom thickness, the morphology of the transparent sheets could have a greater effect on the performance of organic light-emitting diode (OLED) devices with graphene films than on that with indium tin oxide (ITO). In this study, we have evaluated the polymer OLED devices with graphene films synthesized by plasma treatment on poly(ethylene terephthalate) (PET) and poly(ethylene naphthalate) (PEN) sheets having high flatness. The results imply that the surface roughness of the transparent sheets predominantly affects the luminescence of polymer OLED devices with graphene films. The suppression of leakage current and a luminescence higher than 8000 cd/m2 at 15 V were attained for the devices on the transparent sheet with higher flatness in spite of the presence of large sharp spikes.

  12. 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.

  13. 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.

  14. Plasma etching for advanced polymer optical devices

    NASA Astrophysics Data System (ADS)

    Bitting, Donald S.

    Plasma etching is a common microfabrication technique which can be applied to polymers as well as glasses, metals, and semiconductors. The fabrication of low loss and reliable polymer optical devices commonly makes use of advanced microfabrication processing techniques similar in nature to those utilized in standard semiconductor fabrication technology. Among these techniques, plasma/reactive ion etching is commonly used in the formation of waveguiding core structures. Plasma etching is a powerful processing technique with many potential applications in the emerging field of polymer optical device fabrication. One such promising application explored in this study is in the area of thin film-substrate adhesion enhancement. Two approaches involving plasma processing were evaluated to improve substrate-thin film adhesion in the production of polymer waveguide optical devices. Plasma treatment of polymer substrates such as polycarbonate has been studied to promote the adhesion of fluoropolymer thin film coatings for waveguide device fabrication. The effects of blanket oxygen plasma etchback on substrate, microstructural substrate feature formation, and the long term performance and reliability of these methods were investigated. Use of a blanket oxygen plasma to alter the polycarbonate surface prior to fluoropolymer casting was found to have positive but limited capability to improve the adhesive strength between these polymers. Experiments show a strong correlation between surface roughness and adhesion strength. The formation of small scale surface features using microlithography and plasma etching on the polycarbonate surface proved to provide outstanding adhesion strength when compared to any other known treatment methods. Long term environmental performance testing of these surface treatment methods provided validating data. Test results showed these process approaches to be effective solutions to the problem of adhesion between hydrocarbon based polymer

  15. Furfuryl methacrylate plasma polymers for biomedical applications.

    PubMed

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

    2016-09-08

    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.

  16. Self-organizing plasmas

    NASA Astrophysics Data System (ADS)

    Hayashi, T.; Sato, T.; Complexity Simulation Group

    1999-03-01

    The primary purpose of this paper is to extract a grand view of self-organization through an extensive computer simulation of plasmas. The assertion is made that self-organization is governed by three key processes, i.e. the existence of an open complex system, the existence of information (energy) sources and the existence of entropy generation and expulsion processes. We find that self-organization takes place in an intermittent fashion when energy is supplied continuously from outside. In contrast, when the system state is suddenly changed into a non-equilibrium state externally, the system evolves stepwise and reaches a minimum energy state. We also find that the entropy production rate is maximized whenever a new ordered structure is created and that if the entropy generated during the self-organizing process is expelled from the system, then the self-organized structure becomes more prominent and clear.

  17. Plasma Processes and Polymers: 16th International Symposium on Plasma Chemistry Taormina, Italy June 22-27, 2003

    NASA Astrophysics Data System (ADS)

    D'Agostino, Riccardo; Favia, Pietro; Oehr, Christian; Wertheimer, Michael R.

    2005-04-01

    This volume compiles essential contributions to the most innovative fields of Plasma Processes and Polymers. High-quality contributions cover the fields of plasma deposition, plasma treatment of polymers and other organic compounds, plasma processes under partial vacuum and at atmospheric pressure, biomedical, textile, automotive, and optical applications as well as surface treatment of bulk materials, clusters, particles and powders. This unique collection of refereed papers is based on the best contributions presented at the 16th International Symposium on Plasma Chemistry in Taormina, Italy (ISPC-16, June 2003). A high class reference of relevance to a large audience in plasma community as well as in the area of its industrial applications.

  18. Physical organic chemistry of supramolecular polymers.

    PubMed

    Serpe, Michael J; Craig, Stephen L

    2007-02-13

    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.

  19. 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

  20. 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)

  1. Polymer-Based Organic Batteries.

    PubMed

    Muench, Simon; Wild, Andreas; Friebe, Christian; Häupler, Bernhard; Janoschka, Tobias; Schubert, Ulrich S

    2016-08-24

    The storage of electric energy is of ever growing importance for our modern, technology-based society, and novel battery systems are in the focus of research. The substitution of conventional metals as redox-active material by organic materials offers a promising alternative for the next generation of rechargeable batteries since these organic batteries are excelling in charging speed and cycling stability. This review provides a comprehensive overview of these systems and discusses the numerous classes of organic, polymer-based active materials as well as auxiliary components of the battery, like additives or electrolytes. Moreover, a definition of important cell characteristics and an introduction to selected characterization techniques is provided, completed by the discussion of potential socio-economic impacts.

  2. 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

  3. Megahertz organic/polymer diodes

    DOEpatents

    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.

  4. 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.

  5. Functional porous organic polymers for heterogeneous catalysis.

    PubMed

    Zhang, Yugen; Riduan, Siti Nurhanna

    2012-03-21

    Porous organic polymers (POPs), a class of highly crosslinked amorphous polymers possessing nano-pores, have recently emerged as a versatile platform for the deployment of catalysts. The bottom-up approach for porous organic polymer synthesis provides the opportunity for the design of polymer frameworks with various functionalities, for their use as catalysts or ligands. This tutorial review focuses on the framework structures and functionalities of catalytic POPs. Their structural design, functional framework synthesis and catalytic reactions are discussed along with some of the challenges.

  6. Photocatalysis in organic and polymer synthesis.

    PubMed

    Corrigan, Nathaniel; Shanmugam, Sivaprakash; Xu, Jiangtao; Boyer, Cyrille

    2016-11-07

    This review, with over 600 references, summarizes the recent applications of photoredox catalysis for organic transformation and polymer synthesis. Photoredox catalysts are metallo- or organo-compounds capable of absorbing visible light, resulting in an excited state species. This excited state species can donate or accept an electron from other substrates to mediate redox reactions at ambient temperature with high atom efficiency. These catalysts have been successfully implemented for the discovery of novel organic reactions and synthesis of added-value chemicals with an excellent control of selectivity and stereo-regularity. More recently, such catalysts have been implemented by polymer chemists to post-modify polymers in high yields, as well as to effectively catalyze reversible deactivation radical polymerizations and living polymerizations. These catalysts create new approaches for advanced organic transformation and polymer synthesis. The objective of this review is to give an overview of this emerging field to organic and polymer chemists as well as materials scientists.

  7. Stable low-fouling plasma polymer coatings on polydimethylsiloxane

    PubMed Central

    Forster, S.; McArthur, S. L.

    2012-01-01

    Polydimethylsiloxane (DMS) is a popular material for microfluidics, but it is hydrophobic and is prone to non-specific protein adsorption. In this study, we explore methods for producing stable, protein resistant, tetraglyme plasma polymer coatings on PDMS by combining extended baking processes with multiple plasma polymer coating steps. We demonstrate that by using this approach, it is possible to produce a plasma polymer coatings that resist protein adsorption (<10 ng/cm2) and are stable to storage over at least 100 days. This methodology can translate to any plasma polymer system, enabling the introduction of a wide range of surface functionalities on PDMS surfaces. PMID:24062864

  8. 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). PMID:27879698

  9. 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.

  10. 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

  11. Electron transporting semiconducting polymers in organic electronics.

    PubMed

    Zhao, Xingang; Zhan, Xiaowei

    2011-07-01

    Significant progress has been achieved in the preparation of semiconducting polymers over the past two decades, and successful commercial devices based on them are slowly beginning to enter the market. However, most of the conjugated polymers are hole transporting, or p-type, semiconductors that have seen a dramatic rise in performance over the last decade. Much less attention has been devoted to electron transporting, or n-type, materials that have lagged behind their p-type counterparts. Organic electron transporting materials are essential for the fabrication of organic p-n junctions, organic photovoltaic cells (OPVs), n-channel organic field-effect transistors (OFETs), organic light-emitting diodes (OLEDs) and complementary logic circuits. In this critical review we focus upon recent developments in several classes of electron transporting semiconducting polymers used in OLEDs, OFETs and OPVs, and survey and analyze what is currently known concerning electron transporting semiconductor architecture, electronic structure, and device performance relationships (87 references).

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

    SciTech Connect

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

    2004-08-09

    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.

  13. Influence of polymer structure on plasma-polymer interactions in resist materials

    NASA Astrophysics Data System (ADS)

    Bruce, Robert Lawson

    The controlled patterning of polymer resists by plasma plays an essential role in the fabrication of integrated circuits and nanostructures. As the dimensions of patterned structures continue to decrease, we require an atomistic understanding underlying the morphological changes that occur during plasma-polymer interactions. In this work, we investigated how plasma surface modifications and the initial polymer structure influenced plasma etch behavior and morphological changes in polymer resists. Using a prototypical argon discharge, we observed polymer modification by ions and vacuum ultraviolet (VUV) radiation from the plasma. A thin, highly dense modified layer was formed at the polymer surface due to ion bombardment. The thickness and physical properties of this ion-damaged layer was independent of polymer structure for the systems examined here. A relationship was observed that strongly suggests that buckling caused by ion-damaged layer formation on a polymer is the origin of roughness that develops during plasma etching. Our results indicate that with knowledge of the mechanical properties of the ion-damaged layer and the polymer being processed, plasma-induced surface roughness can be predicted and the surface morphology calculated. Examining a wide variety of polymer structures, the polymer poly(4-vinylpyridine) (P4VP) was observed to produce extremely smooth surfaces during high-ion energy plasma etching. Our data suggest that VUV crosslinking of P4VP below the ion-damaged layer may prevent wrinkling. We also studied another form of resists, silicon-containing polymers that form a SiO2 etch barrier layer during O2 plasma processing. In this study, we examined whether assisting SiO2 layer formation by adding Si-O bonds to the polymer structure would improve O2 etch behavior and reduce polymer surface roughness. Our results showed that while adding Si-O bonds decreased etch rates and silicon volatilization during O2 plasma exposure, the surface roughness

  14. 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.

  15. Graft polymerization and plasma treatment of polymer membranes for fouling reduction: a review.

    PubMed

    Kochkodan, Victor M; Sharma, Virender K

    2012-01-01

    This article presents a review of recent developments in surface modification of polymer membranes via graft polymerization and plasma treatment for reduction of fouling with organic compounds and microorganisms in pressure driven membrane processes. The factors affecting membrane fouling, such as membrane hydrophilicity, charge and surface roughness are discussed. The recent studies in which the reduction of organic fouling and biofouling by the modification of the membrane surface via ultraviolet/redox initiated surface grafting of hydrophilic polymers and low temperature plasma treatment are reviewed.

  16. Bloch oscillations in organic and inorganic polymers

    NASA Astrophysics Data System (ADS)

    Ribeiro, Luiz Antonio; Ferreira da Cunha, Wiliam; de Almeida Fonseca, Antonio Luciano; e Silva, Geraldo Magela

    2017-04-01

    The transport of polarons above the mobility threshold in organic and inorganic polymers is theoretically investigated in the framework of a one-dimensional tight-binding model that includes lattice relaxation. The computational approach is based on parameters for which the model Hamiltonian suitably describes different polymer lattices in the presence of external electric fields. Our findings show that, above critical field strengths, a dissociated polaron moves through the polymer lattice as a free electron performing Bloch oscillations. These critical electric fields are considerably smaller for inorganic lattices in comparison to organic polymers. Interestingly, for inorganic lattices, the free electron propagates preserving charge and spin densities' localization which is a characteristic of a static polaron. Moreover, in the turning points of the spatial Bloch oscillations, transient polaron levels are formed inside the band gap, thus generating a fully characterized polaron structure. For the organic case, on the other hand, no polaron signature is observed: neither in the shape of the distortion—those polaron profile signatures are absent—nor in the energy levels—as no such polaron levels are formed during the simulation. These results solve controversial aspects concerning Bloch oscillations recently reported in the literature and may enlighten the understanding about the charge transport mechanism in polymers above their mobility edge.

  17. Thiazolothiazole-linked porous organic polymers

    DOE PAGES

    Zhu, Xiang; Tian, Chengcheng; Jin, Tian; ...

    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.

  18. 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.

  19. Organic Polymers with Magneto-Dielectric Properties

    DTIC Science & Technology

    2007-03-28

    These diradicals were intended as ligands (monomers) in ferrimagnetic coordination polymers magneto-dielectricproperties. 15. SUBJECT TERMS20 7 5 68... ferrimagnetic coordination polymers, consisting of Lewis basic organic di- and polyradicals and Lewis acidic paramagnetic transition metal ions (Figure 1...have near-perfect parallel alignment. R N-0 FC liýN.. CF, ’ N"M 0 .0 0. 0 N-0---r0---O-N% + O " ." " R F3 cdKý)’ CF3 N R ’,-N ferrimagnetic chain Figure

  20. 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.

  1. Plasma functionalized surface of commodity polymers for dopamine detection

    NASA Astrophysics Data System (ADS)

    Fabregat, Georgina; Osorio, Joaquin; Castedo, Alejandra; Armelin, Elaine; Buendía, Jorge J.; Llorca, Jordi; Alemán, Carlos

    2017-03-01

    We have fabricated potentially generalizable sensors based on polymeric-modified electrodes for the electrochemical detection of dopamine. Sensitive and selective sensors have been successfully obtained by applying a cold-plasma treatment during 1-2 min not only to conducting polymers but also to electrochemically inert polymers, such as polyethylene, polypropylene, polyvinylpyrrolidone, polycaprolactone and polystyrene. The effects of the plasma in the electrode surface activation, which is an essential requirement for the dopamine detection when inert polymers are used, have been investigated using X-ray photoelectron spectroscopy. Results indicate that exposure of polymer-modified electrodes to cold-plasma produces the formation of a large variety of reactive species adsorbed on the electrode surface, which catalyse the dopamine oxidation. With this technology, which is based on the application of a very simple physical functionalization, we have defined a paradox-based paradigm for the fabrication of electrochemical sensors by using inert and cheap plastics.

  2. 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.

  3. Polymer Nanoparticle Superlattices for Organic Photovoltaic Applications

    SciTech Connect

    Sumpter, Bobby G; Barnes, Mike D.; Venkataraman, Dhandapani; Dinsmore, Anthony D; Labastide, Joelle; Baghgar, Mina; Yang, Yipeng

    2011-01-01

    In this Perspective, we discuss the possibility of constructing binary nanoparticle superlattices for organic photovoltaic applications and some of the interesting new photophysics emerging from preliminary studies. We summarize recent advances in nanoparticle preparation and photophysical characterization and some of the very interesting observed departures from thin-film photoluminescence dynamics. We conclude by discussing some of the challenges ahead and the possibility of new emergent physics in the assembly of polymer nanoparticles into functional devices.

  4. 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.

  5. Phase Behavior of Polymer Blends for Organic Photovoltaic Applications

    NASA Astrophysics Data System (ADS)

    Emerson, Jillian; Furst, Eric; Epps, Thomas, III

    2014-03-01

    Polymer blends offer a promising and economically-viable route to creating organic photovoltaic (OPV) devices, as blends can form bicontinuous domains via spinodal decomposition. Understanding the phase behavior of conjugated polymer blends commonly used in OPVs is vital to producing more efficient devices. In this work, we determined the Flory-Huggins solvent-polymer and polymer-polymer interaction parameters for a model system of poly(3-hexylthiophene) (P3HT) and polystyrene (PS) through solvent vapor swelling of thin polymer films. From these interaction parameters, we constructed a polymer/polymer/solvent phase diagram. The phase diagram was validated experimentally with solution-based transmission measurements of PS/P3HT. This work highlights a method to determine the phase behavior in polymer/polymer/solvent blends that can be extended to other combinations of macromolecules relevant to organic photovoltaics, composites, and other materials systems.

  6. 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.

  7. Porous inorganic—organic shape memory polymers

    PubMed Central

    Zhang, Dawei; Burkes, William L.; Schoener, Cody A.; Grunlan, Melissa A.

    2012-01-01

    Thermoresponsive shape memory polymers (SMPs) are a type of stimuli-sensitive materials that switch from a temporary shape back to their permanent shape upon exposure to heat. While the majority of SMPs have been fabricated in the solid form, porous SMP foams exhibit distinct properties and are better suited for certain applications, including some in the biomedical field. Like solid SMPs, SMP foams have been restricted to a limited group of organic polymer systems. In this study, we prepared inorganic–organic SMP foams based on the photochemical cure of a macromer comprised of inorganic polydimethylsiloxane (PDMS) segments and organic poly(ε-caprolactone) (PCL) segments, diacrylated PCL40-block-PDMS37-block-PCL40. To achieve tunable pore size with high interconnectivity, the SMP foams were prepared via a refined solvent-casting/particulate-leaching (SCPL) method. By varying design parameters such as degree of salt fusion, macromer concentration in the solvent and salt particle size, the SMP foams with excellent shape memory behavior and tunable pore size, pore morphology, and modulus were obtained. PMID:22956854

  8. 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.

  9. 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

  10. Template-assisted generation of nanocavities within plasma polymer films.

    PubMed

    Vasilev, Krasimir; Casanal, Ana; Challougui, Hela; Griesser, Hans J

    2009-05-21

    The generation of nanosized cavities within thin film layers is of interest for a number of fundamental and applied reasons. One challenge is to make such systems sufficiently robust mechanically. Plasma polymer (pp) films possess excellent mechanical stability if deposition conditions are selected such as to achieve a sufficient density of cross-linking and resistance to extraction of polymeric material by solvents. In this study, gold nanoparticles of 15 and 70 nm diameter were used as sacrificial templates to generate nanocavities in pp films of various thickness values in the tens of nanometers range. A first pp layer was deposited onto substrates using n-heptylamine (HA) to a thickness of 20 nm. Carboxy-thiolated gold nanoparticles were electrostatically bound onto the surface amine groups of the n-heptylamine plasma polymer (HApp) layer. A second HApp layer was then coated to various thicknesses onto the nanoparticle/HApp surface. The template particles embedded thus in-between the two HApp layers were then dissolved using aqueous KCN solution; monitoring of the plasmon resonance band of the gold nanoparticles enabled verification of template stripping and measurement of the kinetics of stripping. AFM topography images showed little change on extraction of the template nanoparticles, indicating that the plasma polymer layer maintained structural integrity upon template extraction and subsequent drying, and thereby prevented collapse of the empty nanocavities. The concept of template stripping to generate controlled size free volume in thin plasma polymer layers is thus shown to produce robust structures.

  11. Behavior of organic polymers in drinking water purification.

    PubMed

    Lee, J F; Liao, P M; Tseng, D H; Wen, P T

    1998-09-01

    Synthetic organic polymers used to purify drinking water are severely limited in that their impurities and by-products harm human health. In this study, the undesired effects resulted from chlorination and the enhanced attenuation of toxic organic compounds in drinking water from using synthetic organic polymer coagulants were investigated. In the simulated drinking water purification processes, synthetic organic polymers were used as coagulant aids, reacted with a disinfectant(chlorine) and formed a large number of volatile organic compounds (VOCs). Chloroform and benzene which, are carcinogenic compounds, had the maximum formation potential. Experimental results indicated that the total formation potential of these disinfection by-products significantly increased in the presence of turbidity. On the other hand, adding organic polymers to the coagulation systems resulted in more extensive remove of toxic organic compounds and turbidity. In coagulation and flocculation processes, the formation of clay/polymer complexes can facilitate the removal of toxic organic compounds in contaminated water.

  12. 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.

  13. Conducting Polymers and Their Hybrids as Organic Thermoelectric Materials

    NASA Astrophysics Data System (ADS)

    Toshima, Naoki; Ichikawa, Shoko

    2015-01-01

    Conducting polymers have received much attention recently as organic thermoelectric materials, because of such advantages as plentiful resources, easy synthesis, easy processing, low cost, low thermal conductivity, and easy fabrication of flexible, light, and printable devices with large area. Many reports on organic thermoelectric materials have recently been published. We have studied conducting polymers as organic thermoelectric materials since 1999. During these investigations, we found that the thermal conductivity of conducting polymers did not increase even though electrical conductivity increased; this was a major advantage of conducting polymers as organic thermoelectric materials. We also observed that molecular alignment was one of the most important factors for improvement of the thermoelectric performance of conducting polymers. Stretching of conducting polymers or their precursors was one of the most common techniques used to achieve good molecular alignment. Recently, alignment of the clusters of conducting polymers by treatment with solvents has been proposed as a means of achieving high electrical conductivity. Hybridization of conducting polymers with inorganic nanoparticles has also been found to improve thermoelectric performance. Here we present a brief history and discuss recent progress of research on conducting polymers as organic thermoelectric materials, and describe the techniques used to improve thermoelectric performance by treatment of conducting polymers with solvents and hybridization of conducting polymers with Bi2Te3 and gold nanoparticles.

  14. Fabrication of polymer nanowires via maskless O2 plasma etching.

    PubMed

    Du, Ke; Wathuthanthri, Ishan; Liu, Yuyang; Kang, Yong Tae; Choi, Chang-Hwan

    2014-04-25

    In this paper, we introduce a simple fabrication technique which can pattern high-aspect-ratio polymer nanowire structures of photoresist films by using a maskless one-step oxygen plasma etching process. When carbon-based photoresist materials on silicon substrates are etched by oxygen plasma in a metallic etching chamber, nanoparticles such as antimony, aluminum, fluorine, silicon or their compound materials are self-generated and densely occupy the photoresist polymer surface. Such self-masking effects result in the formation of high-aspect-ratio vertical nanowire arrays of the polymer in the reactive ion etching mode without the necessity of any artificial etch mask. Nanowires fabricated by this technique have a diameter of less than 50 nm and an aspect ratio greater than 20. When such nanowires are fabricated on lithographically pre-patterned photoresist films, hierarchical and hybrid nanostructures of polymer are also conveniently attained. This simple and high-throughput fabrication technique for polymer nanostructures should pave the way to a wide range of applications such as in sensors, energy storage, optical devices and microfluidics systems.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Conjugated Polymer Design and Engineering for Organic Electronics

    NASA Astrophysics Data System (ADS)

    Woo, Claire Hoi Kar

    The molecular structure of a conjugated polymer critically impacts its physical and optoelectronic properties, thus determining its ultimate performance in organic electronic devices. In this work, new polymers and derivatives are designed, synthesized, characterized, and tested in photovoltaic devices. Through device engineering and nanoscale characterization, general structure-function relationships are established to aid the design of the next-generation of high performance polymer semiconductors for organic electronic applications. Using a prototypical conjugated polymer, the influence of backbone regioregularity is examined and found to highly impact polymer crystallinity, solid state morphology and device stability. The investigation of alternative aromatic units in the backbone also led to new understandings in polymer processability and the development of promising materials for organic photovoltaics. Besides the backbone structure, the side chain choice of the polymer can significantly affect material properties and device performance as well. In fact, the side chain substitution can influence both the optoelectronic properties and the physical properties of the polymer. A sterically bulky side chain can be used to tune the donor/acceptor separation distance, which in turn determines the charge separation efficiency. The addition of a polar side group increases the dielectric constant of a polymer and improves overall charge separation. Choosing the appropriate solubilizing group can also induce solid state packing of the polymer and considerably enhance device efficiency. Finally, the influence of post-fabrication processing techniques on the crystallinity and charge transport properties of a polymer is highlighted.

  2. Study on hydrophilicity of polymer surfaces improved by plasma treatment

    NASA Astrophysics Data System (ADS)

    Lai, Jiangnan; Sunderland, Bob; Xue, Jianming; Yan, Sha; Zhao, Weijiang; Folkard, Melvyn; Michael, Barry D.; Wang, Yugang

    2006-03-01

    Surface properties of polycarbonate (PC), polypropylene (PP), polyethylene terephthalate (PET) samples treated by microwave-induced argon plasma have been studied with contact angle measurement, X-ray photoelectron spectroscopy (XPS) and scanned electron microscopy (SEM). It is found that plasma treatment modified the surfaces both in composition and roughness. Modification of composition makes polymer surfaces tend to be highly hydrophilic, which mainly depended on the increase of ratio of oxygen-containing group as same as other papers reported. And this experiment further revealed that C dbnd O bond is the key factor to the improvement of the hydrophilicity of polymer surfaces. Our SEM observation on PET shown that the roughness of the surface has also been improved in micron scale and it has influence on the surface hydrophilicity.

  3. 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.

  4. Organic thin film transistor by using polymer electrolyte to modulate the conductivity of conjugated polymer

    NASA Astrophysics Data System (ADS)

    Lin, Yu-Ju; Li, Yu-Chang; Yeh, Chih-Chieh; Chung, Sheng-Feng; Huang, Li-Ming; Wen, Ten-Chin; Wang, Yeong-Her

    2006-11-01

    This work presents an organic thin film transistor using double polymer layers, polymer electrolyte/conjugated polymer, i.e., poly(diallyldimethylammonium chloride) (PDDA)/poly(diphenylamine) (PDPA) structure. The single mobile anions (Cl-) pending on the PDDA are stuffed into the conjugated polymer to dope the nitrogen atoms (imine) by applying the gate bias, resulting a higher drain current under the same source-drain voltage. The PDDA/PDPA polymer structure working in the enhancement mode which operates under atmospheric conditions as a typical p-channel transistor is demonstrated.

  5. Imaging spectroscopy of polymer ablation plasmas for laser propulsion applications

    NASA Astrophysics Data System (ADS)

    Jiao, Long; Truscott, Benjamin S.; Liu, Hao; Ashfold, Michael N. R.; Ma, Honghao

    2017-01-01

    A number of polymers have been proposed for use as propellants in space launch and thruster applications based on laser ablation, although few prior studies have either evaluated their performance at background pressures representative of the upper atmosphere or investigated interactions with ambient gases other than air. Here, we use spatially and temporally resolved optical emission spectroscopy to compare three polymers, poly(ethylene), poly(oxymethylene), and glycidyl azide polymer, ablated using a 532 nm, nanosecond pulsed laser under Ar and O2 at pressures below 1 Torr. Emission lines from neutrally and positively charged atoms are observed in each case, along with the recombination radiation at the interaction front between the plasma plume and the background gas. C2 radicals arise either as a direct fragmentation product or by a three-body recombination of C atoms, depending on the structure of the polymer backbone, and exhibit a rotational temperature of ≈5000 K. The Sedov-Taylor point blast model is used to infer the energy release relative to the incident laser energy, which for all polymers is greater in the presence of O2, as to be expected based on their negative oxygen balance. Under Ar, plume confinement is seen to enhance the self-reactivity of the ejecta from poly(oxymethylene) and glycidyl azide polymer, with maximum exothermicity close to 0.5 Torr. However, little advantage of the latter, widely considered one of the most promising energetic polymers, is apparent under the present conditions over the former, a common engineering plastic.

  6. Etching of polymers, proteins and bacterial spores by atmospheric pressure DBD plasma in air

    NASA Astrophysics Data System (ADS)

    Kuzminova, A.; Kretková, T.; Kylián, O.; Hanuš, J.; Khalakhan, I.; Prukner, V.; Doležalová, E.; Šimek, M.; Biederman, H.

    2017-04-01

    Many studies proved that non-equilibrium discharges generated at atmospheric pressure are highly effective for the bio-decontamination of surfaces of various materials. One of the key processes that leads to a desired result is plasma etching and thus the evaluation of etching rates of organic materials is of high importance. However, the comparison of reported results is rather difficult if impossible as different authors use diverse sources of atmospheric plasma that are operated at significantly different operational parameters. Therefore, we report here on the systematic study of the etching of nine different common polymers that mimic the different structures of more complicated biological systems, bovine serum albumin (BSA) selected as the model protein and spores of Bacillus subtilis taken as a representative of highly resistant micro-organisms. The treatment of these materials was performed by means of atmospheric pressure dielectric barrier discharge (DBD) sustained in open air at constant conditions. All tested polymers, BSA and spores, were readily etched by DBD plasma. However, the measured etching rates were found to be dependent on the chemical structure of treated materials, namely on the presence of oxygen in the structure of polymers.

  7. Synthetic strategies for the generation of molecularly imprinted organic polymers.

    PubMed

    Mayes, A G; Whitcombe, M J

    2005-12-06

    Molecular imprinting is a method of inducing molecular recognition properties in synthetic polymers in response to the presence of a template species during formation of the three-dimensional structure of the polymer. The molecularly imprinted polymers (MIPs) prepared in this way have been termed "plastic antibodies" and combine the robustness of the polymer scaffold with binding properties more readily associated with biological receptors. Smart polymers of this type may find applications in drug delivery, controlled release and monitoring of drug and metabolite concentrations. In this review the main synthetic strategies used in the preparation of imprinted organic polymers are described in terms of the chemical principles used in the templating step. These are illustrated with examples taken from the literature and are classified as covalent, semi-covalent, non-covalent, metal-mediated and non-polar. Finally strategies for the selection of monomers, optimisation and modification of the properties of imprinted polymers are reviewed.

  8. Touching polymer chains by organic field-effect transistors.

    PubMed

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

    2014-09-17

    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.

  9. Decohesion kinetics in polymer organic solar cells.

    PubMed

    Bruner, Christopher; Novoa, Fernando; Dupont, Stephanie; Dauskardt, Reinhold

    2014-12-10

    We investigate the role of molecular weight (MW) of the photoactive polymer poly(3-hexylthiophene) (P3HT) on the temperature-dependent decohesion kinetics of bulk heterojunction (BHJ) organic solar cells (OSCs). The MW of P3HT has been directly correlated to its carrier field effect mobilities and the ambient temperature also affects OSC in-service performance and P3HT arrangement within the BHJ layer. Under inert conditions, time-dependent decohesion readily occurs within the BHJ layer at loads well below its fracture resistance. We observe that by increasing the MW of P3HT, greater resistance to decohesion is achieved. However, failure consistently occurs within the BHJ layer representing the weakest layer within the device stack. Additionally, it was found that at temperatures below the glass transition temperature (∼41-45 °C), decohesion was characterized by brittle failure via molecular bond rupture. Above the glass transition temperature, decohesion growth occurred by a viscoelastic process in the BHJ layer, leading to a significant degree of viscoelastic deformation. We develop a viscoelastic model based on molecular relaxation to describe the resulting behavior. The study has implications for OSC long-term reliability and device performance, which are important for OSC production and implementation.

  10. Naphthobischalcogenadiazole Conjugated Polymers: Emerging Materials for Organic Electronics.

    PubMed

    Osaka, Itaru; Takimiya, Kazuo

    2017-02-27

    π-Conjugated polymers are an important class of materials for organic electronics. In the past decade, numerous polymers with donor-acceptor molecular structures have been developed and used as the active materials for organic devices, such as organic field-effect transistors (OFETs) and organic photovoltaics (OPVs). The choice of the building unit is the primary step for designing the polymers. Benzochalcogenadiazoles (BXzs) are one of the most familiar acceptor building units studied in this area. As their doubly fused system, naphthobischalcogenadiazoles (NXzs), i.e., naphthobisthiadiazole (NTz), naphthobisoxadiazole (NOz), and naphthobisselenadiazole (NSz) are emerging building units that provide interesting electronic properties and highly self-assembling nature for π-conjugated polymers. With these fruitful features, π-conjugated polymers based on these building units demonstrate great performances in OFETs and OPVs. In particular, in OPVs, NTz-based polymers have exhibited more than 10% efficiency, which is among the highest values reported so far. In this Progress Report, the synthesis, properties, and structures of NXzs and their polymers is summarized. The device performance is also highlighted and the structure-property relationships of the polymers are discussed.

  11. Quantifying self-organization in fusion plasmas

    NASA Astrophysics Data System (ADS)

    Rajković, M.; Milovanović, M.; Škorić, M. M.

    2017-05-01

    A multifaceted framework for understanding self-organization in fusion plasma dynamics is presented which concurrently manages several important issues related to the nonlinear and multiscale phenomena involved, namely,(1) it chooses the optimal template wavelet for the analysis of temporal or spatio-temporal plasma dynamics, (2) it detects parameter values at which bifurcations occur, (3) it quantifies complexity and self-organization, (4) it enables short-term prediction of nonlinear dynamics, and (5) it extracts coherent structures in turbulence by separating them from the incoherent component. The first two aspects including the detection of changes in the dynamics of a nonlinear system are illustrated by analyzing Stimulated Raman Scattering in a bounded, weakly dissipative plasma. Self-organization in the fusion plasma is quantitatively analyzed based on the numerical simulations of the Gyrokinetic-Vlasov (GKV) model of plasma dynamics. The parameters for the standard and inward shifted magnetic configurations, relevant for the Large Helical Device, were used in order to quantitatively compare self-organization and complexity in the two configurations. Finally, self-organization is analyzed for three different confinement regimes of the MAST device.

  12. Surface Modification of Conventional Polymers by Depositing Plasma Polymers of Trimethylsilane and of Trimethylsilane + O2.

    PubMed

    Weikart; Miyama; Yasuda

    1999-03-01

    The static wetting properties of TMS (trimethylsilane) and TMS + O2 plasma deposited films on eleven low energy conventional polymers were investigated using the sessile droplet method. The static advancing contact angle is an excellent indication of the change in surface state properties from plasma surface modification. However, traditional contact angle measuring techniques possess a methodological limitation, which can leave a water droplet on the substrate surface for up to 3 min before a measurement is obtained. The static "advancing" contact angles of different size water droplets on teflon and nylon surfaces were observed to change significantly in 2 min while equilibrating with the surface and surroundings. A new quick image-capturing device enables static contact angle measurement 2 to 4 s after contact with the substrate. This technique virtually eliminates the time dependent effects of evaporation and surface state change, which are believed to be responsible for the change in static advancing contact angles. Furthermore, static contact angles independent of droplet volume and contact time may be taken as a surface characteristic property, which is denoted as the intrinsic static contact angle, θS. The static "advancing" contact angle, measured in this fashion, indicated that the wetting properties of TMS and TMS + O2 plasma polymer deposition on 10 conventional polymers were modified virtually independent of the underlying substrate. The average advancing contact angles on TMS and TMS + O2 modified polymers are θS = 94 +/- 2.2 (cos θS = -0.0645) and θS = 32 +/- 6.9 (cos θS = 0.8452), respectively. Copyright 1999 Academic Press.

  13. 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.

  14. 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.

  15. Plasma-modified and polyethylene glycol-grafted polymers for potential tissue engineering applications.

    PubMed

    Svorcík, V; Makajová, Z; Kasálková-Slepicková, N; Kolská, Z; Bacáková, L

    2012-08-01

    Modified and grafted polymers may serve as building blocks for creating artificial bioinspired nanostructured surfaces for tissue engineering. Polyethylene (PE) and polystyrene (PS) were modified by Ar plasma and the surface of the plasma activated polymers was grafted with polyethylene glycol (PEG). The changes in the surface wettability (contact angle) of the modified polymers were examined by goniometry. Atomic Force Microscopy (AFM) was used to determine the surface roughness and morphology and electrokinetical analysis (Zeta potential) characterized surface chemistry of the modified polymers. Plasma treatment and subsequent PEG grafting lead to dramatic changes in the polymer surface morphology, roughness and wettability. The plasma treated and PEG grafted polymers were seeded with rat vascular smooth muscle cells (VSMCs) and their adhesion and proliferation were studied. Biological tests, performed in vitro, show increased adhesion and proliferation of cells on modified polymers. Grafting with PEG increases cell proliferation, especially on PS. The cell proliferation was shown to be an increasing function of PEG molecular weight.

  16. Inkjet-Printed Organic Transistors Based on Organic Semiconductor/Insulating Polymer Blends.

    PubMed

    Kwon, Yoon-Jung; Park, Yeong Don; Lee, Wi Hyoung

    2016-08-02

    Recent advances in inkjet-printed organic field-effect transistors (OFETs) based on organic semiconductor/insulating polymer blends are reviewed in this article. Organic semiconductor/insulating polymer blends are attractive ink candidates for enhancing the jetting properties, inducing uniform film morphologies, and/or controlling crystallization behaviors of organic semiconductors. Representative studies using soluble acene/insulating polymer blends as an inkjet-printed active layer in OFETs are introduced with special attention paid to the phase separation characteristics of such blended films. In addition, inkjet-printed semiconducting/insulating polymer blends for fabricating high performance printed OFETs are reviewed.

  17. Inkjet-Printed Organic Transistors Based on Organic Semiconductor/Insulating Polymer Blends

    PubMed Central

    Kwon, Yoon-Jung; Park, Yeong Don; Lee, Wi Hyoung

    2016-01-01

    Recent advances in inkjet-printed organic field-effect transistors (OFETs) based on organic semiconductor/insulating polymer blends are reviewed in this article. Organic semiconductor/insulating polymer blends are attractive ink candidates for enhancing the jetting properties, inducing uniform film morphologies, and/or controlling crystallization behaviors of organic semiconductors. Representative studies using soluble acene/insulating polymer blends as an inkjet-printed active layer in OFETs are introduced with special attention paid to the phase separation characteristics of such blended films. In addition, inkjet-printed semiconducting/insulating polymer blends for fabricating high performance printed OFETs are reviewed. PMID:28773772

  18. 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.

  19. Research of spin-orbit interaction in organic conjugated polymers

    NASA Astrophysics Data System (ADS)

    Li, H.; Zhou, M. Y.; Wu, S. Y.; Liang, X. R.

    2017-06-01

    The effect of spin-orbit interaction on the one-dimensional organic polymer was investigated theoretically. Spin-orbital interaction led to the spatial separation of energy band but did not eliminate spin degeneration, which was different from energy level splitting in the Zeeman Effect. Spin-orbit interaction had little effect on the energy band structure, charge density, and lattice position, etc.; Spin precession was obtained when a polaron was transported along the polymer chain, which theoretically proved that it was feasible to control the spin precession of polaron in organic polymers by the use of external electric field.

  20. 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.

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

    DOE PAGES

    Baxamusa, Salmaan H.; Suresh, Aravind; Ehrmann, Paul; ...

    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

  2. Carbazole-based polymers for organic photovoltaic devices.

    PubMed

    Li, Jiaoli; Grimsdale, Andrew C

    2010-07-01

    Polymers based upon 2,7-disubstituted carbazole have recently become of great interest as electron-donating materials in organic photovoltaic devices. In this tutorial review the synthesis of such polymers and their relative performances in such devices are surveyed. In particular structure-property relationships are investigated and the potential for the rational design of materials for high efficiency solar cells is discussed. In the case of the 2,7-carbazole homopolymer it has been found that electron acceptors other than fullerenes produce higher energy conversion efficiencies. To get around possible problems with the build-up of charge density at the 3- and 6-positions and to improve the solar light harvesting ability of the polymers by reducing the bandgap, ladder- and step-ladder type 2,7-carbazole polymers have been synthesised. The fully ladderised polymers gave very poor results in devices, but efficiencies of over 1% have been obtained from a step-ladder polymer with a diindenocarbazole monomer unit. Donor-acceptor copolymers containing 2,7-carbazole donors and various electron-accepting comonomer units have been prepared. An efficiency of 6% has been reported from a device using such a copolymer and by suitable choice of the acceptor comonomer, polymers can be designed with potential theoretical power conversion efficiencies of 10%. While such efficiencies remain to be obtained, the results to date certainly suggest that carbazole-based polymers and copolymers are among the most promising materials yet proposed for obtaining high efficiency organic solar cells.

  3. Silica nanoparticles treated by cold atmospheric-pressure plasmas improve the dielectric performance of organic-inorganic nanocomposites.

    PubMed

    Yan, Wei; Han, Zhao Jun; Phung, B Toan; Ostrikov, Kostya Ken

    2012-05-01

    We report on the application of cold atmospheric-pressure plasmas to modify silica nanoparticles to enhance their compatibility with polymer matrices. Thermally nonequilibrium atmospheric-pressure plasma is generated by a high-voltage radio frequency power source operated in the capacitively coupled mode with helium as the working gas. Compared to the pure polymer and the polymer nanocomposites with untreated SiO(2), the plasma-treated SiO(2)-polymer nanocomposites show higher dielectric breakdown strength and extended endurance under a constant electrical stress. These improvements are attributed to the stronger interactions between the SiO(2) nanoparticles and the surrounding polymer matrix after the plasma treatment. Our method is generic and can be used in the production of high-performance organic-inorganic functional nanocomposites.

  4. A Polymer-Supported Organic Reaction: Seeing Is Believing

    NASA Astrophysics Data System (ADS)

    Hailstone, E.; Huther, N.; Parsons, A. F.

    2003-12-01

    Polymer-supported reactions have recently been shown to provide an important alternative approach to preparing organic compounds. Whereas traditional solution-phase syntheses can involve lengthy workup procedures leading to the isolation of organic products, the use of solid polymer supports considerably simplifies this process and products are recovered by filtration and washing procedures. These types of reactions can be used in combinatorial chemistry to prepare large numbers of compounds both quickly and efficiently. This method has found particular application in the pharmaceutical industry. However, the progress of reactions on polymer supports can be difficult to follow and, for example, thin-layer chromatography cannot be used if the starting material and product are covalently bound to the polymer. One simple method for determining the progress of reactions on polymer supports involves the use of chemical stains. These selectively react with certain functional groups to form highly-colored products. In this laboratory experiment, an amide-coupling reaction is carried out on a polymer support, and the reaction is monitored using different chemical stains. This effectively demonstrates, through color changes, the reaction of a polymer-supported amine that provides students with valuable practical experience of this important and modern advance in organic chemistry methodology.

  5. 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.

  6. New organic nanoporous polymers and their inclusion complexes

    SciTech Connect

    Ma, M.; Li, D.

    1999-04-01

    The authors have recently fabricated cyclodextrin polymers that exhibit an interconnected nanoporosity with a dramatically increased inclusion formation constant, K {ge} 10{sup 8} M{sup {minus}1}. This is significant because a simple conversion from cyclodextrin monomers to nanoporous polymers could have such a dramatic effect on noncovalent interactions in aqueous solutions. Previous studies on cyclodextrin polymers focus mostly on cross-linking cyclodextrin with epichlorohydrin which is commercially available and has low binding constant to organics. Studies using cyclodextrins to coat solid particles as a stationary phase for enantiomer separation were also reported. Formation of inclusion complexes are rarely proven in these cyclodextrin polymers, including using cholesterol as a template to synthesize cyclodextrin polymers.

  7. Lifetime of organic light emitting diodes on polymer anodes

    NASA Astrophysics Data System (ADS)

    Fehse, Karsten; Meerheim, Rico; Walzer, Karsten; Leo, Karl; Lövenich, Wilfried; Elschner, Andreas

    2008-08-01

    We report on the use of a thin layer of poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) as anode for bottom emission organic light emitting diodes (OLEDs). The combination of polymer anodes with OLEDs having either electrically doped or undoped hole transport layers in direct contact with the polymer is shown. We discuss the impact of the annealing conditions of the polymer on the OLED lifetime in comparison to indium tin oxide anodes. Supported by a differential thermal analysis of PEDOT:PSS, a strong influence of residual water in the polymer on the device lifetime is found. Additional heating of the polymer anode in a dry ambient prior to OLED deposition is necessary to achieve high device lifetimes. At a luminance of 260 cd/m2, pin-OLEDs on a PEDOT:PSS anode show no measurable device degradation during 5200 h of operation.

  8. Organic-inorganic hybrid polymer-encapsulated magnetic nanobead catalysts.

    PubMed

    Arai, Takayoshi; Sato, Toru; Kanoh, Hirofumi; Kaneko, Katsumi; Oguma, Koichi; Yanagisawa, Akira

    2008-01-01

    A new strategy for the encapsulation of magnetic nanobeads was developed by using the in situ self-assembly of an organic-inorganic hybrid polymer. The hybrid polymer of {[Cu(bpy)(BF(4))(2)(H(2)O)(2)](bpy)}(n) (bpy=4,4'-bipyridine) was constructed on the surface of amino-functionalized magnetic beads and the resulting hybrid-polymer-encapsulated beads were utilized as catalysts for the oxidation of silyl enolates to provide the corresponding alpha-hydroxy carbonyl compounds in high yield. After the completion of the reaction, the catalyst was readily recovered by magnetic separation and the recovered catalyst could be reused several times. Because the current method did not require complicated procedures for incorporating the catalyst onto the magnetic beads, the preparation and the application of various other types of organic-inorganic hybrid-polymer-coated magnetic beads could be possible.

  9. Organic Polymer Light Emitting Display for Digital Mammography

    DTIC Science & Technology

    2003-03-01

    J . Gruener, R.N. Marks, R.H. Friend, S.C. Moratti and A.B. Holmes, " Light - Emitting Diodes Fabricated with Conjugated ...surprised when a group at Cambridge University (U.K.) demonstrated the first light - emitting plastic device - the organic polymer light - emitting diode (OLED... Polymers - Recent Progress," Synthetic Metals, 67, 3 (1994). 2. J . Kido, M. Kimura, and K. Nagai, "Multilayer White Light - Emitting

  10. Polymer-encapsulated organic nanoparticles for fluorescence and photoacoustic imaging.

    PubMed

    Li, Kai; Liu, Bin

    2014-09-21

    Polymer encapsulated organic nanoparticles have recently attracted increasing attention in the biomedical field because of their unique optical properties, easy fabrication and outstanding performance as imaging and therapeutic agents. Of particular importance is the polymer encapsulated nanoparticles containing conjugated polymers (CP) or fluorogens with aggregation induced emission (AIE) characteristics as the core, which have shown significant advantages in terms of tunable brightness, superb photo- and physical stability, good biocompatibility, potential biodegradability and facile surface functionalization. In this review, we summarize the latest advances in the development of polymer encapsulated CP and AIE fluorogen nanoparticles, including preparation methods, material design and matrix selection, nanoparticle fabrication and surface functionalization for fluorescence and photoacoustic imaging. We also discuss their specific applications in cell labeling, targeted in vitro and in vivo imaging, blood vessel imaging, cell tracing, inflammation monitoring and molecular imaging. We specially focus on strategies to fine-tune the nanoparticle property (e.g. size and fluorescence quantum yield) through precise engineering of the organic cores and careful selection of polymer matrices. The review also highlights the merits and limitations of these nanoparticles as well as strategies used to overcome the limitations. The challenges and perspectives for the future development of polymer encapsulated organic nanoparticles are also discussed.

  11. Experimental beam system studies of plasma-polymer interactions

    NASA Astrophysics Data System (ADS)

    Nest, Dustin George

    Since the invention of the integrated circuit, the semiconductor industry has relied on the shrinking of device dimensions to increase device performance and decrease manufacturing costs. However, the high degree of roughening observed during plasma etching of current generation photoresist (PR) polymers can result in poor pattern transfer and ultimately decreased device performance or failure. Plasma-surface interactions are inherently difficult to study due to the highly coupled nature of the plasma enviroment. To better understand these interactions, a beam system approach is employed where polymers are exposed to beams of ions and vacuum ultraviolet (VUV) photons. Through the use of the beam system approach, simultaneous VUV radiation, ion bombardment, and moderate substrate heating have been identified as key elements, acting synergistically, as being responsible for roughening of current generation 193 nm PR during plasma processing. Sequential exposure is not adequate for the development of surface roughness, as observed through AFM and SEM. Ion bombardment results in the formation of a graphitized near-surface region with a depth of a few nanometers, the expected ion penetration depth of 150 eV argon ions. In contrast, VUV radiation results in the loss of carbon-oxygen bonds in the bulk PR as observed through Transmission FTIR. Based on the differing penetration depth of either ions or photons, their resulting chemical modifications, and the temperature dependence of the observed roughening, a mechanism is proposed based on stress relaxation resulting in surface buckling. The surface roughness of poly(4-methyl styrene) (P4MS) and poly(alpha-methyl styrene) (PalphaMS) have also been investigated under exposure to ions and VUV photons. PaMS degrades during VUV radiation above its ceiling temperature of ˜60°C. Despite having the same chemical composition as PalphaMS, P4MS does not degrade during VUV exposure at 70°C due to its relatively high ceiling

  12. Controlled Growth of Metal-Organic Frameworks on Polymer Brushes.

    PubMed

    Hou, Liman; Zhou, Mingdong; Dong, Xiaozhe; Wang, Lei; Xie, Zhigang; Dong, Dewen; Zhang, Ning

    2017-08-17

    Polymer brushes are for the first time used to induce the synthesis of metal-organic frameworks (MOFs). The semi-fixed polymer chains provide a confined environment, which allows a mild growth of MOFs in between polymer chains to give surface-attached spherical MOF nanoparticles, in contrast to the larger MOF cubes/plates formed simultaneously in solution. Polymer brushes bearing carboxylate acid functionalities are indispensable for the formation of surface bound MOFs, while no MOF nanoparticles are observed on neutral polymer brushes. Characterization of the resultant MOF/polymer brushes hybrid film indicates the formation of crystalline MOF structure. The dimension of surface-attached MOFs can be fine-tuned from 20 nm to 1.4 μm simply by varying the structural parameter of polymer brushes and the nucleation duration. The method is not only applicable to the synthesis of MOF-5 and MIL-125, but shows great potential for the preparation of other surface-attached MOFs. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. 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.

  14. Properties of the acrylic acid polymers obtained by atmospheric pressure plasma polymerization

    NASA Astrophysics Data System (ADS)

    Topala, Ionut; Dumitrascu, Nicoleta; Popa, Gheorghe

    2009-01-01

    Plasma polymers of acrylic acid were obtained using an atmospheric pressure discharge system. The plasma polymerization reactor uses a dielectric barrier discharge, with the polyethylene terephthalate dielectric acting as substrate for deposition. The plasma was characterized by specific electrical measurements, monitoring the applied voltage and the discharge current. Based on the spatially resolved optical emission spectroscopy, we analyzed the distribution of the excited species in the discharge gap, specific plasma temperatures (vibrational and gas temperatures) being calculated with the Boltzmann plot method. The properties of the plasma polymer films were investigated by contact angle measurements, infrared and UV-Vis spectroscopy, scanning electron microscopy. The films produced by plasma polymerization at atmospheric pressure showed a hydrophilic character, in correlation with the strong absorbance of OH groups in the FTIR spectrum. Moreover, the surface of the plasma polymers at micrometric scale is smooth and free of defects without particular features.

  15. 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.

  16. 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.

  17. The material balance of process of plasma-chemical conversion of polymer wastes into synthesis gas

    NASA Astrophysics Data System (ADS)

    Tazmeev, A. Kh; Tazmeeva, R. N.

    2017-01-01

    The process of conversion of polymer wastes in the flow of water-steam plasma which are created by the liquid electrodes plasma generators was experimentally studied. The material balance was calculated. The regularities of the participating of hydrogen and oxygen which contained in the water-steam plasma, in formation of chemical compounds in the final products were revealed.

  18. 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.

  19. Nanotexturing of Conjugated Polymers via One-Step Maskless Oxygen Plasma Etching for Enhanced Tunable Wettability.

    PubMed

    Jiang, Youhua; Xu, Jian; Lee, Junghoon; Du, Ke; Yang, Eui-Hyeok; Moon, Myoung-Woon; Choi, Chang-Hwan

    2017-07-11

    A one-step maskless oxygen plasma etching process is investigated to nanopattern conjugated polymer dodecylbenzenesulfonate doped polypyrrole (PPy(DBS)) and to examine the effects of nanostructures on the inherent tunable wettability of the surface and the droplet mobility. Etching characteristics such as the geometry and dimensions of the nanostructures are systematically examined for the etching power and duration. The mechanism of self-formation of vertically aligned dense-array pillared nanostructures in the one-step maskless oxygen plasma etching process is also investigated. Results show that lateral dimensions such as the periodicity and diameter of the pillared nanostructures are insensitive to the etching power and duration, whereas the length and aspect ratio of the nanostructures increase with them. X-ray photoelectron spectroscopy analysis and thermal treatment of the polymer reveal that the codeposition of impurities on the surface resulting from the holding substrate is the primary reason for the self-formation of nanostructures during the oxygen plasma etching, whereas the local crystallinity subject to thermal treatment has a minor effect on the lateral dimensions. Retaining the tunable wettability (oleophobicity) for organic droplets during the electrochemical redox (i.e., reduction and oxidization) process, the nanotextured PPy(DBS) surface shows significant enhancement of droplet mobility compared to that of the flat PPy(DBS) surface with no nanotexture by making the surface superoleophobic (i.e., in a Cassie-Baxter wetting state). Such enhancement of the tunable oleophobicity and droplet mobility of the conjugated polymer will be of great significance in many applications such as microfluidics, lab-on-a-chip devices, and water/oil treatment.

  20. Novel thiophene-containing semiconducting polymers for organic electronic applications

    NASA Astrophysics Data System (ADS)

    Hundt, Nadia Khanam

    The pi-conjugated polymers such as polythiophenes (PT's) represent a class of organic-based materials that possess unique optical and electronic properties. The electronic properties of such conjugated macromolecules are primarily governed by the chemical structure of the polymer backbone itself. Synthesizing new conjugated polymers by further functionalizing precursor monomers is an attractive route to enhance optical and electronic properties of these materials. The introduction of an unsaturated side chain will encourage solid-state pi-pi stacking and allow for facile post polymerization chemical modification. Additionally, a number of other tools can be employed in order to adjust the electronic properties of conjugated polymers. Tuning the band gap of conjugated polymers and introduction of liquid crystalline segments are two important strategies to tune the opto-electronic and physical properties of these materials. The research efforts of this thesis have been directed towards the design, synthesis, and electronic characterization of well-defined novel semiconducting thiophene-based polymers. Chapter 1 focuses on the synthesis and characterization of novel poly (3-alkenylthiophene) derivatives. The copolymers have been investigated as the active layer in organic field-effect transistors. The surface morphology of polymer films has been analyzed by AFM microscopy. Chapter 2 describes the synthesis of novel semiconducting polymers with extended electron delocalization. Semiconducting polymers containing a fused benzodithiophene core with phenylethynyl substituents were prepared and characterized. The electronic properties and morphologies of the synthesized homopolymers and copolymers containing benzodithiophene with phenylethynyl substituents were correlated with their molecular structures. The synthesized polymers have a lower band gap due to the extended electron delocalization. Chapter 3 describes the synthesis of a novel rod-rod di-block copolymer

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

    PubMed

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

    2013-07-29

    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.

  2. 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

  3. 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.

  4. 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.

  5. 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.

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

    NASA Astrophysics Data System (ADS)

    Bae, Junwan; Lee, I. J.

    2015-05-01

    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.

  7. Organic phototransistors with nanoscale phase-separated polymer/polymer bulk heterojunction layers.

    PubMed

    Hwang, Hyemin; Kim, Hwajeong; Nam, Sungho; Bradley, Donal D C; Ha, Chang-Sik; Kim, Youngkyoo

    2011-05-01

    Low-cost detectors for sensing photons at a low light intensity are of crucial importance in modern science. Phototransistors can deliver better signals of low-intensity light by electrical amplification, but conventional inorganic phototransistors have a limitation owing to their high temperature processes in vacuum. In this work, we demonstrate organic phototransistors with polymer/polymer bulk heterojunction blend films (mixtures of p-type and n-type semiconducting polymers), which can be fabricated by inexpensive solution processes at room temperature. The key idea here is to effectively exploit hole charges (from p-type polymer) as major signaling carriers by employing p-type transistor geometry, while the n-type polymer helps efficient charge separation from excitons generated by incoming photons. Results showed that the present organic transistors exhibited proper functions as p-type phototransistors with ∼4.3 A W(-1) responsivity at a low light intensity (1 µW cm(-2)), which supports their encouraging potential to replace conventional cooled charge coupled devices (CCD) for low-intensity light detection applications.

  8. Damage-free polymer surface modification employing inward-type plasma

    NASA Astrophysics Data System (ADS)

    Kanou, Ryo; Suga, Hiroshi; Utsumi, Hideyuki; Takahashi, Satoshi; Shirayama, Yuya; Watanabe, Norimichi; Petit, Stèphane; Shimizu, Tetsuo

    2017-08-01

    Inward-type plasmas, which spread upstream against the gas flow in the capillary tube where the gas is discharged, can react with samples placed near the entrance of such a capillary tube. In this study, surface modification of polymer surfaces is conducted using inward plasma. The modification is also done by conventional microplasma jet, and the modified surfaces with two plasma techniques are characterized by contact angle measurement, X-ray photoemission spectroscopy (XPS), and atomic force microscopy (AFM). Although inward-plasma-treated surfaces are less hydrophilic than conventional plasma-treated ones, they are still sufficiently hydrophilic for surface coatings. In addition, it turns out that the polymer surfaces irradiated with the inward plasma yield much smoother surfaces than those treated with the conventional plasma jet. Thus, the inward plasma treatment is a viable technique when the surface flatness is crucial, such as for the surface coating of plastic lenses.

  9. Molecularly imprinted polymers as selective adsorbents for ambient plasma mass spectrometry.

    PubMed

    Cegłowski, Michał; Smoluch, Marek; Reszke, Edward; Silberring, Jerzy; Schroeder, Grzegorz

    2017-05-01

    The application of molecularly imprinted polymers (MIPs) as molecular scavengers for ambient plasma ionization mass spectrometry has been reported for the first time. MIPs were synthesized using methacrylic acid as functional monomer; nicotine, propyphenazone, or methylparaben as templates; ethylene glycol dimethacrylate as a cross-linker; and 2,2'-azobisisobutyronitrile as polymerization initiator. To perform ambient plasma ionization experiments, a setup consisting of the heated crucible, a flowing atmospheric-pressure afterglow (FAPA) plasma ion source, and a quadrupole ion trap mass spectrometer has been used. The heated crucible with programmable temperature allows for desorption of the analytes from MIPs structure which results in their direct introduction into the ion stream. Limits of detection, linearity of the proposed analytical procedure, and selectivities have been determined for three analytes: nicotine, propyphenazone, and methylparaben. The analytes used were chosen from various classes of organic compounds to show the feasibility of the analytical procedure. The limits of detections (LODs) were 10 nM, 10, and 0.5 μM for nicotine, propyphenazone, and methylparaben, respectively. In comparison with the measurements performed for the non-imprinted polymers, the values of LODs were improved for at least one order of magnitude due to preconcentration of the sample and reduction of background noise, contributing to signal suppression. The described procedure has shown linearity in a broad range of concentrations. The overall time of single analysis is short and requires ca. 5 min. The developed technique was applied for the determination of nicotine, propyphenazone, and methylparaben in spiked real-life samples, with recovery of 94.6-98.4%. The proposed method is rapid, sensitive, and accurate which provides a new option for the detection of small organic compounds in various samples. Graphical abstract The experimental setup used for analysis.

  10. 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.

  11. Applications of Organic and Polymer Nonlinear Optical Materials in Optics Computations.

    DTIC Science & Technology

    1995-03-27

    Organic and polymer nonlinear optical materials have good properties in optics, structure, and mechanics. At present, such materials are...undergoing rapid development. This article emphasizes presenting some typical organic and polymer nonlinear optical materials , describes the optical

  12. Active screen plasma nitriding enhances cell attachment to polymer surfaces

    NASA Astrophysics Data System (ADS)

    Kaklamani, Georgia; Bowen, James; Mehrban, Nazia; Dong, Hanshan; Grover, Liam M.; Stamboulis, Artemis

    2013-05-01

    Active screen plasma nitriding (ASPN) is a well-established technique used for the surface modification of materials, the result of which is often a product with enhanced functional performance. Here we report the modification of the chemical and mechanical properties of ultra-high molecular weight poly(ethylene) (UHMWPE) using 80:20 (v/v) N2/H2 ASPN, followed by growth of 3T3 fibroblasts on the treated and untreated polymer surfaces. ASPN-treated UHMWPE showed extensive fibroblast attachment within 3 h of seeding, whereas fibroblasts did not successfully attach to untreated UHMWPE. Fibroblast-coated surfaces were maintained for up to 28 days, monitoring their metabolic activity and morphology throughout. The chemical properties of the ASPN-treated UHMWPE surface were studied using X-ray photoelectron spectroscopy, revealing the presence of Csbnd N, Cdbnd N, and Ctbnd N chemical bonds. The elastic modulus, surface topography, and adhesion properties of the ASPN-treated UHMWPE surface were studied over 28 days during sample storage under ambient conditions and during immersion in two commonly used cell culture media.

  13. Thiophene polymer semiconductors for organic thin-film transistors.

    PubMed

    Ong, Beng S; Wu, Yiliang; Li, Yuning; Liu, Ping; Pan, Hualong

    2008-01-01

    Printed organic thin-film transistors (OTFTs) have received great interests as potentially low-cost alternative to silicon technology for application in large-area, flexible, and ultra-low-cost electronics. One of the critical materials for TFTs is semiconductor, which has a dominant impact on the transistor properties. We review here the structural studies and design of thiophene-based polymer semiconductors with respect to solution processability, ambient stability, molecular self-organization, and field-effect transistor properties for OTFT applications. We show that through judicial monomer design, delicately controlled pi-conjugation, and strategically positioned pendant side-chain distribution, novel solution-processable thiophene polymer semiconductors with excellent self-organization ability to form extended lamellar pi-stacking orders can be developed. OTFTs using semiconductors of this nature processed in ambient conditions have provided excellent field-effect transistor properties.

  14. 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.

  15. 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.

  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. Creation of hydrophilic nitric oxide releasing polymers via plasma surface modification.

    PubMed

    Pegalajar-Jurado, A; Joslin, J M; Hawker, M J; Reynolds, M M; Fisher, E R

    2014-08-13

    Herein, we describe the surface modification of an S-nitrosated polymer derivative via H2O plasma treatment, resulting in polymer coatings that maintained their nitric oxide (NO) releasing capabilities, but exhibited dramatic changes in surface wettability. The poly(lactic-co-glycolic acid)-based hydrophobic polymer was nitrosated to achieve a material capable of releasing the therapeutic agent NO. The NO-loaded films were subjected to low-temperature H2O plasma treatments, where the treatment power (20-50 W) and time (1-5 min) were varied. The plasma treated polymer films were superhydrophilic (water droplet spread completely in <100 ms), yet retained 90% of their initial S-nitrosothiol content. Under thermal conditions, NO release profiles were identical to controls. Under buffer soak conditions, the NO release profile was slightly lowered for the plasma-treated materials; however, they still result in physiologically relevant NO fluxes. XPS, SEM-EDS, and ATR-IR characterization suggests the plasma treatment resulted in polymer rearrangement and implantation of hydroxyl and carbonyl functional groups. Plasma treated samples maintained both hydrophilic surface properties and NO release profiles after storage at -18 °C for at least 10 days, demonstrating the surface modification and NO release capabilities are stable over time. The ability to tune polymer surface properties while maintaining bulk properties and NO release properties, and the stability of those properties under refrigerated conditions, represents a unique approach toward creating enhanced therapeutic biopolymers.

  18. Optical limiter with an organic solution sandwiched between a polymer slab and a polymer grating

    SciTech Connect

    Chen Ming; Li Chunfei; Zhang Yundong; Xu Mai; Ma Shaojie; Wang Weibiao; Xia Yuxue

    2005-08-10

    An optical limiter was designed and fabricated. The device consists of an organic solution sandwiched between a polymer slab and a transparent relief polymer grating with a triangular groove. At low power the device has a high transmittance because the refractive index of the solution is matched with those of the slab and the grating materials and because the grating does not diffract. However, high power makes the organic solution thermally vaporize and makes the indices of the solution, slab, and grating materials become mismatched, which causes the grating to appear. The incident light is strongly absorbed, scattered, and self-defocused by the organic solution, and the grating suppresses the zero-order diffraction. Thus the transmitted light energy becomes lower than the damage threshold of human eyes or optical sensors. The device is an effective protection for human eyes or optical sensors against broadband pulsed-laser damage.

  19. 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.

  20. Enzymatic synthesis of organic-polymer-grafted DNA.

    PubMed

    Baccaro, Anna; Marx, Andreas

    2010-01-04

    To create bioorganic hybrid materials, interdisciplinary work in the fields of chemistry, biology and materials science is conducted. DNA block copolymers are promising hybrid materials due to the combination of properties intrinsic to both the polymer and the nucleic acid blocks. Until now, the coupling of DNA and organic polymers has been exercised post-synthetically in solution or on solid support. Herein, we report the first enzyme-catalysed synthesis of DNA-organic polymer chimeras. For this purpose, four novel 2'-deoxyuridine triphosphates carrying polymer-like moieties linked to the nucleobase were synthesised. Linear polyethylene glycol monomethyl ethers of different sizes (1) and branched polyamido dendrons with varying terminal groups (2) were chosen as building blocks. We investigated the ability of DNA polymerases to accept the copolymers in comparison to the natural substrate and showed, through primer extensions, polymerase chain reactions and rolling circle amplification, that these building blocks could serve as a surrogate for the natural thymidine. By this method, DNA hybrid materials with high molecular weight, modification density, and defined structure are accessible.

  1. 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

  2. Hydrogenated amorphous silicon solar cell on organic polymer substrate

    NASA Astrophysics Data System (ADS)

    Okaniwa, H.; Nakatani, K.; Asano, M.; Suzuki, K.; Yano, M.; Hirasaka, M.; Hamakawa, Y.

    1983-01-01

    The basic properties of a solar cell based on an organic polymer film are reported and the characteristics peculiar to the organic polymer substrate are discussed. The electrical conductivity and activation energy of doped a-Si:H deposited on glass substrate at various temperatures and under various RF powers are shown. The open circuit voltage, short circuit current, fill factor, and conversion efficiency of solar cells on polyimide film and SUS plate in sunlight of 92.5 mW/sq cm are given, as are relative characteristic values of solar cells fabricated simultaneously on various substrates under that illumination. Compositional profiles of p-i-n structure solar cells on sp-SUS over SUS plate and SUS plate substrates are shown along with surface morphology of SUS plate, SUS/sp-SUS, and polyimide/sp-SUS substrates.

  3. Comparison of glow argon plasma-induced surface changes of thermoplastic polymers

    NASA Astrophysics Data System (ADS)

    Řezníčková, A.; Kolská, Z.; Hnatowicz, V.; Stopka, P.; Švorčík, V.

    2011-01-01

    Modification of high-density polyethylene (PE), polytetrafluoroethylene (PTFE), polystyrene (PS), polyethyleneterephthalate (PET) and polypropylene (PP) by Ar plasma was studied. The amount of the ablated material was determined by gravimetry. Wettability of polymers after the plasma treatment was determined from the contact angle measurement. The changes in the surface morphology of polymers were observed using atomic force microscopy (AFM). Chemical structure of modified polymers was characterized by X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR). Surface changes were also studied by the determination of electrokinetic potential ( ζ-potential). It was found that under the plasma treatment the polymers are ablated and their surface morphology and roughness are changed dramatically. XPS measurements indicate an oxidation of the polymer surface. The plasma treatment results in a dramatic increase of the ζ-potential. EPR data show different radical amount present on the treated surface of all polymers. Most significant changes due to the degradation of polymer chains are observed on PTFE.

  4. Simple methods for polymer nanostructuring by plasma modification, metal sputtering, and annealing

    NASA Astrophysics Data System (ADS)

    Jurik, Petr; Slepicka, Petr; Svorcik, Vaclav

    2016-09-01

    Self-organization offer cost-efficient and easily scalable way to nanopattern polymer surfaces for various applications ranging from medical use to sensing applications. For example poly-L-lactic acid can be modified either by metal sputtering and/or plasma discharge to form ripple-like structures after annealing with size and regularity highly dependent on processing variables. Such samples have enhanced biocompatibility and as such they are promising substrates for use as various implants. Another example is annealing of polyethersulfone film modified by metal sputtering that causes coalescence of metal layer into separated metal nanoclusters. This structure exhibit localized surface Plasmon resonance, which can be used for example in Surface enhanced Raman spectroscopy.

  5. 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.

  6. Microporous organic polymers for gas storage and separation applications.

    PubMed

    Chang, Ze; Zhang, Da-Shuai; Chen, Qiang; Bu, Xian-He

    2013-04-21

    Microporous organic polymers (MOPs), an emerging class of functional porous materials featured with the pure organic component have been widely studied in recent years. These materials have potential uses in areas such as storage, separation, and catalysis. In this Perspective, we focused on the gas storage and separation of MOPs. The targeted design and synthesis of MOPs toward the enhancement of gas capacity and selectivity are discussed. Furthermore, special emphasis is given to the post-synthesis modification of MOPs which have been proved to be effective methods to accurately tune the desired properties.

  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. 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.

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

    SciTech Connect

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

    2014-09-22

    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.

  10. 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.

  11. Crosslinkable low bandgap polymers for organic solar cells

    NASA Astrophysics Data System (ADS)

    Strohriegl, Peter; Saller, Christina; Knauer, Philipp; Köhler, Anna; Hahn, Tobias; Fischer, Florian; Kahle, Frank-Julian

    2016-09-01

    We present a number of polyfluorene based conjugated polymers with crosslinkable acrylate and oxetane units. These polymers can be crosslinked by free radical polymerization in the case of acrylates and by cationic ring opening polymerization for oxetanes. Upon polymerization densely crosslinked networks are formed which are completely insoluble. We show that the diffusion coefficient of C60 in polyfluorene is reduced by a factor of 1000 by crosslinking. MIS-CELIV measurements are used to monitor changes in the charge carrier mobility upon crosslinking. It shows that using appropriate conditions, e.g. low initiator concentrations or thermal crosslinking, the charge carrier mobility is not reduced by crosslinking. Solution processed three layer organic solar cells were realized with a crosslinkable fluorene based copolymer containing acrylate groups. The efficiency is increased from 1.4% for the reference to 1.8% in the three layer cell with a crosslinked exciton blocking layer. A critical issue of BHJ cells is the instability of the morphology of the polymer:fullerene blend over long operation times at elevated temperature. We present a crosslinkable derivative of the low bandgap polymer PFDTBT which contains oxetane units. BHJ cells with the crosslinked PFDTBT derivative and PCBM were tested in accelerated aging experiments at 100 °C for times up to 100 h. Stabilization was clearly observed in crosslinked BHJ cells compared to the non-crosslinked reference. We show for the first time that oxetane containing polymers can be thermally crosslinked without any added initiator. Initiator free crosslinking is particularly attractive as it avoids the formation of decomposition products, and thus potential electron traps and quenching sites from the initiator.

  12. 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.

  13. 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.

  14. Treatment of polymer surfaces in plasma Part II. Qualitative analysis

    NASA Astrophysics Data System (ADS)

    Svirachev, D. M.; Tabaliov, N. A.

    2006-07-01

    In this paper, the solutions of kinetic model are qualitatively analyzed. The model describes treatment of polymer surfaces in RF-discharge (12.56 MHz). The treating of polymer surfaces in different gases leads to alteration of surface tension of the material. The experimental bearings for wetting contact angle and work of adhesion during the time of treating are compared with theoretical results obtained from the model. As a pattern polymer material, polyethylene terephthalate (PET) is used in plasmacreating gases: argon (Ar), oxygen (O2), Freon 14 (CF4) and Freon 12 (CF2Cl2).

  15. Intrinsically stretchable and healable semiconducting polymer for organic transistors.

    PubMed

    Oh, Jin Young; Rondeau-Gagné, Simon; Chiu, Yu-Cheng; Chortos, Alex; Lissel, Franziska; Wang, Ging-Ji Nathan; Schroeder, Bob C; Kurosawa, Tadanori; Lopez, Jeffrey; Katsumata, Toru; Xu, Jie; Zhu, Chenxin; Gu, Xiaodan; Bae, Won-Gyu; Kim, Yeongin; Jin, Lihua; Chung, Jong Won; Tok, Jeffrey B-H; Bao, Zhenan

    2016-11-17

    Thin-film field-effect transistors are essential elements of stretchable electronic devices for wearable electronics. All of the materials and components of such transistors need to be stretchable and mechanically robust. Although there has been recent progress towards stretchable conductors, the realization of stretchable semiconductors has focused mainly on strain-accommodating engineering of materials, or blending of nanofibres or nanowires into elastomers. An alternative approach relies on using semiconductors that are intrinsically stretchable, so that they can be fabricated using standard processing methods. Molecular stretchability can be enhanced when conjugated polymers, containing modified side-chains and segmented backbones, are infused with more flexible molecular building blocks. Here we present a design concept for stretchable semiconducting polymers, which involves introducing chemical moieties to promote dynamic non-covalent crosslinking of the conjugated polymers. These non-covalent crosslinking moieties are able to undergo an energy dissipation mechanism through breakage of bonds when strain is applied, while retaining high charge transport abilities. As a result, our polymer is able to recover its high field-effect mobility performance (more than 1 square centimetre per volt per second) even after a hundred cycles at 100 per cent applied strain. Organic thin-film field-effect transistors fabricated from these materials exhibited mobility as high as 1.3 square centimetres per volt per second and a high on/off current ratio exceeding a million. The field-effect mobility remained as high as 1.12 square centimetres per volt per second at 100 per cent strain along the direction perpendicular to the strain. The field-effect mobility of damaged devices can be almost fully recovered after a solvent and thermal healing treatment. Finally, we successfully fabricated a skin-inspired stretchable organic transistor operating under deformations that might be

  16. Intrinsically stretchable and healable semiconducting polymer for organic transistors

    NASA Astrophysics Data System (ADS)

    Oh, Jin Young; Rondeau-Gagné, Simon; Chiu, Yu-Cheng; Chortos, Alex; Lissel, Franziska; Wang, Ging-Ji Nathan; Schroeder, Bob C.; Kurosawa, Tadanori; Lopez, Jeffrey; Katsumata, Toru; Xu, Jie; Zhu, Chenxin; Gu, Xiaodan; Bae, Won-Gyu; Kim, Yeongin; Jin, Lihua; Chung, Jong Won; Tok, Jeffrey B.-H.; Bao, Zhenan

    2016-11-01

    Thin-film field-effect transistors are essential elements of stretchable electronic devices for wearable electronics. All of the materials and components of such transistors need to be stretchable and mechanically robust. Although there has been recent progress towards stretchable conductors, the realization of stretchable semiconductors has focused mainly on strain-accommodating engineering of materials, or blending of nanofibres or nanowires into elastomers. An alternative approach relies on using semiconductors that are intrinsically stretchable, so that they can be fabricated using standard processing methods. Molecular stretchability can be enhanced when conjugated polymers, containing modified side-chains and segmented backbones, are infused with more flexible molecular building blocks. Here we present a design concept for stretchable semiconducting polymers, which involves introducing chemical moieties to promote dynamic non-covalent crosslinking of the conjugated polymers. These non-covalent crosslinking moieties are able to undergo an energy dissipation mechanism through breakage of bonds when strain is applied, while retaining high charge transport abilities. As a result, our polymer is able to recover its high field-effect mobility performance (more than 1 square centimetre per volt per second) even after a hundred cycles at 100 per cent applied strain. Organic thin-film field-effect transistors fabricated from these materials exhibited mobility as high as 1.3 square centimetres per volt per second and a high on/off current ratio exceeding a million. The field-effect mobility remained as high as 1.12 square centimetres per volt per second at 100 per cent strain along the direction perpendicular to the strain. The field-effect mobility of damaged devices can be almost fully recovered after a solvent and thermal healing treatment. Finally, we successfully fabricated a skin-inspired stretchable organic transistor operating under deformations that might be

  17. Correlation between the plasma characteristics and the surface chemistry of plasma-treated polymers through partial least-squares analysis.

    PubMed

    Mavadat, Maryam; Ghasemzadeh-Barvarz, Massoud; Turgeon, Stéphane; Duchesne, Carl; Laroche, Gaétan

    2013-12-23

    We investigated the effect of various plasma parameters (relative density of atomic N and H, plasma temperature, and vibrational temperature) and process conditions (pressure and H2/(N2 + H2) ratio) on the chemical composition of modified poly(tetrafluoroethylene) (PTFE). The plasma parameters were measured by means of near-infrared (NIR) and UV-visible emission spectroscopy with and without actinometry. The process conditions of the N2-H2 microwave discharges were set at various pressures ranging from 100 to 2000 mTorr and H2/(N2+H2) gas mixture ratios between 0 and 0.4. The surface chemical composition of the modified polymers was determined by X-ray photoelectron spectroscopy (XPS). A mathematical model was constructed using the partial least-squares regression algorithm to correlate the plasma information (process condition and plasma parameters as determined by emission spectroscopy) with the modified surface characteristics. To construct the model, a set of data input variables containing process conditions and plasma parameters were generated, as well as a response matrix containing the surface composition of the polymer. This model was used to predict the composition of PTFE surfaces subjected to N2-H2 plasma treatment. Contrary to what is generally accepted in the literature, the present data demonstrate that hydrogen is not directly involved in the defluorination of the surface but rather produces atomic nitrogen and/or NH radicals that are shown to be at the origin of fluorine atom removal from the polymer surface. The results show that process conditions alone do not suffice in predicting the surface chemical composition and that the plasma characteristics, which cannot be easily correlated with these conditions, should be considered. Process optimization and control would benefit from plasma diagnostics, particularly infrared emission spectroscopy.

  18. polyMOFs: A Class of Interconvertible Polymer-Metal-Organic-Framework Hybrid Materials.

    PubMed

    Zhang, Zhenjie; Nguyen, Ha Thi Hoang; Miller, Stephen A; Cohen, Seth M

    2015-05-18

    Preparation of porous materials from one-dimensional polymers is challenging because the packing of polymer chains results in a dense, non-porous arrangement. Herein, we demonstrate the remarkable adaptation of an amorphous, linear, non-porous, flexible organic polymer into a three-dimensional, highly porous, crystalline solid, as the organic component of a metal-organic framework (MOF). A polymer with aromatic dicarboxylic acids in the backbone functioned as a polymer ligand upon annealing with Zn(II), generating a polymer-metal-organic framework (polyMOF). These materials break the dogma that MOFs must be prepared from small, rigid ligands. Similarly, polyMOFs contradict conventional polymer chemistry by demonstrating that linear and amorphous polymers can be readily coaxed into a highly crystalline, porous, three-dimensional structure by coordination chemistry. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. 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...

  20. Hydroxylation of organic polymer surface: method and application.

    PubMed

    Yang, Peng; Yang, Wantai

    2014-03-26

    It may be hardly believable that inert C-H bonds on a polymeric material surface could be quickly and efficiently transformed into C-OH by a simple and mild way. Thanks to the approaches developed recently, it is now possible to transform surface H atoms of a polymeric substrate into monolayer OH groups by a simple/mild photochemical reaction. Herein the method and application of this small-molecular interfacial chemistry is highlighted. The existence of hydroxyl groups on material surfaces not only determines the physical and chemical properties of materials but also provides effective reaction sites for postsynthetic sequential modification to fulfill the requirements of various applications. However, organic synthetic materials based on petroleum, especially polyolefins comprise mainly C and H atoms and thus present serious surface problems due to low surface energy and inertness in reactivity. These limitations make it challenging to perform postsynthetic surface sequential chemical derivatization toward enhanced functionalities and properties and also cause serious interfacial problems when bonding or integrating polymer substrates with natural or inorganic materials. Polymer surface hydroxylation based on direct conversion of C-H bonds on polymer surfaces is thus of significant importance for academic and practical industrial applications. Although highly active research results have reported on small-molecular C-H bond activation in solution (thus homogeneous), most of them, featuring the use of a variety of transition metals as catalysts, present a slow reaction rate, a low atom economy and an obvious environmental pollution. In sharp contrast to these conventional C-H activation strategies, the present Spotlight describes a universal confined photocatalytic oxidation (CPO) system that is able to directly convert polymer surface C-H bonds to C-OSO3(-) and, subsequently, to C-OH through a simple hydrolysis. Generally speaking, these newly implanted hydroxyl

  1. 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.

  2. Nanostructural self-organization and dynamic adaptation of metal-polymer tribosystems

    NASA Astrophysics Data System (ADS)

    Mashkov, Yu. K.

    2017-02-01

    The results of investigating the effect of nanosize modifiers of a polymer matrix on the nanostructural self-organization of polymer composites and dynamic adaptation of metal-polymer tribosystems, which considerably affect the wear resistance of polymer composite materials, have been analyzed. It has been shown that the physicochemical nanostructural self-organization processes are developed in metal-polymer tribosystems with the formation of thermotropic liquid-crystal structures of the polymer matrix, followed by the transition of the system to the stationary state with a negative feedback that ensures dynamic adaptation of the tribosystem to given operating conditions.

  3. Surface chemistry for molecular layer deposition of organic and hybrid organic-inorganic polymers.

    PubMed

    George, Steven M; Yoon, Byunghoon; Dameron, Arrelaine A

    2009-04-21

    The fabrication of many devices in modern technology requires techniques for growing thin films. As devices miniaturize, manufacturers will need to control thin film growth at the atomic level. Because many devices have challenging morphologies, thin films must be able to coat conformally on structures with high aspect ratios. Techniques based on atomic layer deposition (ALD), a special type of chemical vapor deposition, allow for the growth of ultra-thin and conformal films of inorganic materials using sequential, self-limiting reactions. Molecular layer deposition (MLD) methods extend this strategy to include organic and hybrid organic-inorganic polymeric materials. In this Account, we provide an overview of the surface chemistry for the MLD of organic and hybrid organic-inorganic polymers and examine a variety of surface chemistry strategies for growing polymer thin films. Previously, surface chemistry for the MLD of organic polymers such as polyamides and polyimides has used two-step AB reaction cycles using homo-bifunctional reactants. However, these reagents can react twice and eliminate active sites on the growing polymer surface. To avoid this problem, we can employ alternative precursors for MLD based on hetero-bifunctional reactants and ring-opening reactions. We can also use surface activation or protected chemical functional groups. In addition, we can combine the reactants for ALD and MLD to grow hybrid organic-inorganic polymers that should display interesting properties. For example, using trimethylaluminum (TMA) and various diols as reactants, we can achieve the MLD of alucone organic-inorganic polymers. We can alter the chemical and physical properties of these organic-inorganic polymers by varying the organic constituent in the diol or blending the alucone MLD films with purely inorganic ALD films to build a nanocomposite or nanolaminate. The combination of ALD and MLD reactants enlarges the number of possible sequential self-limiting surface

  4. Supramolecular organization of heteroxylan-dehydrogenation polymers (synthetic lignin) nanoparticles.

    PubMed

    Barakat, Abdellatif; Gaillard, Cédric; Lairez, Didier; Saulnier, Luc; Chabbert, Brigitte; Cathala, Bernard

    2008-02-01

    The supramolecular organization of particles composed of heteroxylans (HX) and synthetic lignin (dehydrogenation polymer, DHPs) was studied by light scattering (LS), atomic force microscopy (AFM), and fluorescent probes. Results from static and quasi-elastic light scattering indicate a dense core surrounded by a soft corona. Such organization is also supported by AFM images of the particles that display Gaussian height profiles when a low tapping force is applied, whereas the shape of the profile obtained at a higher mechanical solicitation is irregular and sharp due to deformation of the particles resulting from the tip indentation. This suggests a difference in mechanical behavior between the inner and outer parts of the particles. The formation of local chemical heterogeneities was demonstrated by use of two fluorescent polarity probes (pyrene and methyl-amino-pyrene) to be induced by the core-corona organization.

  5. Molecular structure and exciton dynamics in organic conjugated polymers

    NASA Astrophysics Data System (ADS)

    Thomas, Alan K.

    Intermolecular electronic interactions, dipole coupling and orbital overlap, caused by pi-pi stacking in organic conjugated polymers lead to unique structures and properties that can be harnessed for optoelectronic applications. These interactions define structure-function relationships in amorphous and aggregated forms of polymers in the solid state and determine their efficiencies and functionality in electronic devices, from transistors to solar cells. Organic polymer electronic device performance depends critically upon electronic coupling between monomer units -mediated by conformation and packing characteristics - that dictates electronic properties like conductivity and capacitance as well as electronic processes, such as charge carrier generation and transport. This dissertation demonstrates how electronic processes in conjugated polymers are mediated by subtle inter- and intra-chain electronic interactions imparted by the conformational degrees of freedom within their solid state structure and how this effects device performance. To initiate this investigation into structure-function relationships, an examination of nanoparticles representing two limiting aggregation states of the conjugated polymer poly(3-hexylthiophene) (P3HT) was conducted. These aggregates are defined by their predominate form of electronic coupling, inter- or intrachain, called H- and J-aggregates respectively. H- or J-aggregates of P3HT were embedded in an insulating matrix and time-resolved fluorescence intensity modulation spectroscopy was utilized to uncover the existence of efficient singlet-triplet quenching in J aggregates not present in H-aggregates. These studies were extended by examining P3HT H-and J-aggregates under applied electric fields in capacitor type devices using multiple time-resolved and steady-state spectroscopic techniques. These experiments reveal electronic couplings in J aggregates that shift excited state population towards a majority composed of long lived

  6. Intercalation of alkylamines into an organic polymer crystal

    NASA Astrophysics Data System (ADS)

    Matsumoto, Akikazu; Odani, Toru; Sada, Kazuki; Miyata, Mikiji; Tashiro, Kohji

    2000-05-01

    Organic solid-state synthesis allows formation of products that are difficult or impossible to produce by conventional methods. This feature, and the high degree of reaction selectivity that can be achieved, is a direct result of the control over the relative orientation of the reactants afforded by the solid state. But as the successful development of `topochemical reactions' requires the careful design of suitable reactant crystals, the range of both reactions and products amenable to this approach has been limited. However, recent advances in organic crystal engineering, particularly the rational design of complex solid architectures through supramolecular preorganization, have renewed interest in topochemical reactions. Previously, we have orientated muconate monomers-diene moieties with a carboxylate group on each end-using long-chain n-alkylammonium ions, such that the topochemical photopolymerization of the solid-state reactants produces layered crystals of stereoregular and high-molecular-mass polymers. Here we show that these polymer crystals are capable of repeated, reversible intercalation by conversion to the analogous poly(carboxylic acid), followed by transformation into a number of poly(alkylammonium muconate)s upon addition of the appropriate amine. Introduction of functional groups into these crystals may allow the design of organic solids for applications such as molecular recognition, separation and catalysis, thereby extending the range and practical utility of current intercalation compounds.

  7. Intercalation of alkylamines into an organic polymer crystal

    PubMed

    Matsumoto; Odani; Sada; Miyata; Tashiro

    2000-05-18

    Organic solid-state synthesis allows formation of products that are difficult or impossible to produce by conventional methods. This feature, and the high degree of reaction selectivity that can be achieved, is a direct result of the control over the relative orientation of the reactants afforded by the solid state. But as the successful development of 'topochemical reactions' requires the careful design of suitable reactant crystals, the range of both reactions and products amenable to this approach has been limited. However, recent advances in organic crystal engineering, particularly the rational design of complex solid architectures through supramolecular preorganization, have renewed interest in topochemical reactions. Previously, we have orientated muconate monomers--diene moieties with a carboxylate group on each end--using long-chain n-alkylammonium ions, such that the topochemical photopolymerization of the solid-state reactants produces layered crystals of stereoregular and high-molecular-mass polymers. Here we show that these polymer crystals are capable of repeated, reversible intercalation by conversion to the analogous poly(carboxylic acid), followed by transformation into a number of poly(alkylammonium muconate)s upon addition of the appropriate amine. Introduction of functional groups into these crystals may allow the design of organic solids for applications such as molecular recognition, separation and catalysis, thereby extending the range and practical utility of current intercalation compounds.

  8. New developments in surface functionalization of polymers using controlled plasma treatments

    NASA Astrophysics Data System (ADS)

    Vesel, Alenka; Mozetic, Miran

    2017-07-01

    We are presenting recent advances in surface functionalization of materials such as functional polymers using gaseous plasma treatments. Functionalization is a result of chemical interaction between solid materials and reactive plasma species including charged particles, neutral radicals, excited species and UV radiation. The degree of surface functionalization depends on the type of polymers and fluxes of reactive plasma species. An appropriate choice of plasma parameters thus enables almost arbitrary tailoring of the surface wettability. This review paper gives a brief introduction to the formation of reactive gaseous species upon plasma conditions in different discharge configurations and describes plasma-surface interaction with an emphasis on the differences between different reactive plasma species. Analysis of the relevant literature is given and correlations between treatment parameters and surface finish are drawn. Numerous authors have used plasma treatment for modification of the surface functionalities, however, the obtained surface properties often differ even for the same materials. The reason for such diverse results is the application of various gaseous discharges for plasma generation. Apart from the type and amount of functional groups induced by plasma treatment, the surface functionality depends also on the surface morphology on the sub-micron scale; therefore, this effect is stressed as well. Finally, some future guidelines are given.

  9. 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.

  10. Ultraviolet nanoimprinted polymer nanostructure for organic light emitting diode application

    NASA Astrophysics Data System (ADS)

    Jeon, Sohee; Kang, Jae-Wook; Park, Hyung-Dol; Kim, Jang-Joo; Youn, Jae R.; Shim, Jongyoup; Jeong, Jun-ho; Choi, Dae-Geun; Kim, Ki-Don; Altun, Ali Ozhan; Kim, Se-Heon; Lee, Yong-Hee

    2008-06-01

    Light extraction efficiency of a conventional organic light emitting diode (OLED) remains limited to approximately 20% as most of the emission is trapped in the waveguide and glass modes. An etchless simple method was developed to fabricate two-dimensional nanostructures on glass substrate directly by using ultraviolet (UV) curable polymer resin and UV nanoimprint lithography in order to improve output coupling efficiency of OLEDs. The enhancement of the light extraction was predicted by the three-dimensional finite difference time domain method. OLEDs integrated on nanoimprinted substrates enhanced electroluminance intensity by up to 50% compared to the conventional device.

  11. 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.

  12. 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.

  13. 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.

  14. Course of organized structures in thermal plasma inside and outside argon plasma torch

    NASA Astrophysics Data System (ADS)

    Gruber, Jan; Sonsky, Jiri; Hlina, Jan

    2016-09-01

    Arc chamber of direct-current (dc) argon plasma torch and area just above the nozzle outside of this dc plasma torch were observed by hi-speed camera. System of reflecting mirrors and transparent silica arc chamber walls were used to obtain simultaneous records of both i) cathode area with electric arc inside the plasma torch and ii) nozzle exit with resulting plasma jet outside the plasma torch. Such experimental arrangement allowed us to track localized repeating patterns (organized structures) in the arc chamber and in the plasma flow. Identification of various organized structures - for different experimental conditions - according to their origin and typical development is presented in this paper. Impact of 300 Hz ripple in arc current was compared between different areas of the plasma. Additional simultaneous observation of plasma flow in the same system by series of photodiodes was used for verification of the results. The work was possible with institutional support RVO:61388998.

  15. Preparation of Hydrophilic Polymer Surfaces using Microwave Rectangular Plasma

    NASA Astrophysics Data System (ADS)

    Yoshiki, Hiroyuki; Komatsu, Yuichi; Suzuki, Ayato

    A microwave rectangular plasma was generated over 450 mm long using a sectorial horn antenna with the aperture of 400×10 mm2 and permanent magnets. High density plasma was efficiently produced due to the electron cyclotron resonance (ECR) heating. Ion saturation current density of 5-10 mA/cm2 for Ar plasma was attained in the vicinity of the ECR zone which is close to the quartz window. The spatial plasma uniformity of ±7% was obtained over 300 mm long at 400 W, 1.0 Pa at the position of 160 mm away from the quartz window. This plasma source was applied to the surface modification of the high density poly(ethylene) (HDPE) and poly(tetrafluoroethylene) (PTFE) sheets. After Ar plasma irradiation at 400 W, 10 Pa and 150 s, the contact angles on the HDPE and PTFE surfaces decreased from 82° to 31° and from 90° to 49°, respectively. In addition, the uniformity on the plasma treatment was ±7% for HDPE and ±5% for PTFE over 420 mm long. X-ray photoelectron spectroscopy (XPS) analysis showed that defluorination and the formation of C=O groups appeared on the plasma treated surfaces.

  16. Donor-acceptor semiconducting polymers for organic photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Kularatne, Ruvini S.

    Organic solar cells hold the key for future energy demand due to their unique properties such as low cost, light weight and flexibility. A remarkable amount of effort has been done to improve the power conversion efficiencies in bulk heterojunction solar cells (BHJ). Considerable effort has been done to develop novel donor-acceptor copolymers to improve the absorbance of the copolymer in the visible to near Infrared (IR) regions and to lower the highest occupied molecular orbital (HOMO) energy level of the conjugated polymer as these properties improve the short circuit current density (J SC) and the open circuit voltage (VOC) and hence the power conversion efficiency (PCE) of the BHJ solar cells. In this dissertation, Chapter 1 describes the synthesis and photovoltaic performance of donor-acceptor semiconducting polymers that have been reported during the last decade. 9,9-Dialkyl-2,7-fluorene (FL), 2,7-carbazole (CZ), cyclopenta[2,1-b:3,4-b']dithiophene (CPDT), dithieno[3,2-b:2',3'-d]silole (DTS), dithieno[3,2- b:2',3'-d]pyrrole (DTP), benzo[1,2-b:4,5- b']dithiophene (BDT), benzo[1,2-b:4,5- b']difurane (BDF) building blocks and their donor-acceptor copolymers and their photovoltaic properties have been discussed in this chapter. Chapter 2 describes the synthesis and photovoltaic properties of two novel donor-acceptor polymers P1 and P2 containing benzodithiophene with 3,3',5-trihexylbithienyl substituents as the donor unit with Benzo[c][1,2,5]thiadiazole and 5-hexylthieno[3,4- c]pyrrole-4,6-dione as acceptor building blocks. The photovoltaic properties of the synthesized donor-acceptor polymers were investigated in bulk heterojunction solar cells with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) acceptor. Chapter 3 describes the synthesis of three novel donor-acceptor copolymers P3, P4 and P5 via Stille coupling polymerization with bithienyl substituted BDT as the donor with three different acceptors; 5,6-difluorobenzo[c][1,2,5]thiadiazole, 4,7-di(thiophen-2

  17. 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. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. 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.

  19. 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.

  20. 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.

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

    PubMed Central

    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 104 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. PMID:23591876

  2. Nanostructure control in polymer solar cells by self-organization.

    PubMed

    Tajima, Keisuke; Hashimoto, Kazuhito

    2011-02-01

    Recently, polymer solar cells (PSCs) based on "bulk heterojunctions" using a simple mixture of electron donor and acceptor materials in thin films have been extensively studied. Although relatively high power conversion efficiencies have been achieved by using this approach, further improvement is necessary to precisely construct stable, reproducible nanostructures that are suitable for both efficient charge separation and transport inside such films. For this purpose, it is highly desirable to utilize a bottom-up approach, such as the self-organized formation of inorganic and organic nanostructures. In this review, an overview of our recent studies on the control of nanostructures in PSCs is presented. Copyright © 2011 The Japan Chemical Journal Forum and Wiley Periodicals, Inc.

  3. High Temperature Resistant Organic/Inorganic Hybrid Polymers: An Architectural Study

    DTIC Science & Technology

    2007-04-18

    DATES COVERED July 10 2003 – January 09 2007 4. TITLE AND SUBTITLE High Temperature Resistant Organic/ Inorganic Hybrid Polymers: An...Supramolecular Chemistry, High Temperature Materials, Organic Inorganic Hybrid Materials, Sensors 15. NUMBER OF PAGES 16...298-102 Enclosure 1 2 High Temperature Resistant Organic/ Inorganic Hybrid Polymers: An Architectural Study DAAD19-03-1-0208 PIs Stuart

  4. Plasma Proteome Association and Catalytic Activity of Stealth Polymer-Grafted Iron Oxide Nanoparticles.

    PubMed

    Wang, Miaoyi; Siddiqui, Ghizal; Gustafsson, Ove J R; Käkinen, Aleksandr; Javed, Ibrahim; Voelcker, Nicolas H; Creek, Darren J; Ke, Pu Chun; Davis, Thomas P

    2017-09-01

    Polyethylene glycol (PEG) is widely used as an antifouling and stealth polymer in surface engineering and nanomedicine. However, recent research has revealed adverse effects of bioaccumulation and immunogenicity following the administration of PEG, prompting this proteomic examination of the plasma protein coronae association with superparamagnetic iron oxide nanoparticles (IONPs) grafted with brushed PEG (bPEG) and an alternative, brushed phosphorylcholine (bPC). Using label-free quantitation by liquid chromatography tandem-mass spectrometry, this study determines protein abundances for the in vitro hard coronae of bare, bPC-, and bPEG-grafted IONPs in human plasma. This study also shows unique protein compositions in the plasma coronae of each IONP, including enrichment of coagulation factors and immunogenic complement proteins with bPEG, and enhanced binding of apolipoproteins with bPC. Functional analysis reveals that plasma protein coronae elevate the horseradish peroxidase-like activities of the bPC- and bPEG-IONPs by approximately twofold, an effect likely mediated by the diverse composition and physicochemical properties of the polymers as well as their associated plasma proteins. Taken together, these observations support the rational design of stealth polymers based on a quantitative understanding of the interplay between IONPs and the plasma proteome, and should prove beneficial for the development of materials for nanomedicine, biosensing, and catalysis. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  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. Microwave plasma treatment of polymer surface for irreversible sealing of microfluidic devices.

    PubMed

    Hui, Alex Y N; Wang, Gang; Lin, Bingcheng; Chan, Wing-Tat

    2005-10-01

    Microwave plasma was generated in a glass bottle containing 2-3 Torr of oxygen for plasma treatment of a polymer surface. A "kitchen microwave oven" and a dedicated microwave digestion oven were used as the power source. Poly(dimethylsiloxane)(PDMS) slabs treated by a 30 W plasma for 30-60 s sealed irreversibly to form microfluidic devices that can sustain solution flow of an applied pressure of 42 psi without leaking. Experimental set up and conditions for the production of a homogeneous plasma to activate the PDMS surface for irreversible sealing are described in detail. The surface of a microwave plasma-treated PDMS slab was characterized using atomic force microscopy (AFM) and attenuated total reflection-Fourier Transform infrared spectroscopy (ATR-FTIR). The plasma-treated surface bears silica characteristics.

  7. Solar cells based on organic molecules and polymers

    NASA Astrophysics Data System (ADS)

    Salinas, J. F.; Maldonado, J. L.; Ramos-Ortíz, G.; Rodríguez, M.; Meneses-Nava, M. A.; Barbosa-García, O.; Farfán, N.; Santillan, R.

    2009-09-01

    The search of clean, inexpensive and renewable energy sources is one of the most important challenges that the mankind is currently confronting. Recently there has been a notable interest of the scientific community to develop organic photovoltaic (OPV) technology as a mean of renewable energy source since it combines low-cost and easy fabrication. We have fabricated and tested plastic solar devices (OPVs) by using the bulk heterojunction approach. OPVs were prepared by blending 6-Nitro-3-(E)-3-(4-dimethylaminophenyl)allylidene)-2,3 dihydrobenzo[d][1,3,2]-oxazaborole (M1) and (E)-3-(4-Dimethylaminophenyl)allylidene)-2,3-dihydrobenzo[d]-[1,3,2]oxazaborole (M2), which are conjugated and non-linear low molecular weight molecules prepared in our laboratories, and the well known photoconductor polymer MEH-PPV; fullerene PC61BM was the sensitizer. The morphology of thin polymer films prepared by using the spin coating technique was analyzed by Atomic Force Microscopy (AFM). For the electric contact, commercial and transparent indium tin oxide (ITO) deposited on glass slides was used, and a metal alloy of Pb/Bi/Cd/Sn as cathode, was easily deposited on the polymer film by melting the alloy at 75 °C. Open circuit voltages (Voc) of ~ 700 mV and short circuit currents (Jsc) of ~ 0.75 mA/cm2 under solar (AM1.5) illumination were measured for MEH-PPV and M1 based samples. For OPVs cells based on mixtures of either M1 and MEH-PPV or M2 and MEH-PPV there was a large electrical enhancement showing Voc ~ 700 mV and Jsc ~ 2.0 mA/cm2. OPVs cells were also tested under Xe-lamp illumination. Measurements from the I-V curves gave electrical efficiencies close to 1%.

  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.

  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. Conjugated Polymer Zwitterions: Efficient Interlayer Materials in Organic Electronics.

    PubMed

    Liu, Yao; Duzhko, Volodimyr V; Page, Zachariah A; Emrick, Todd; Russell, Thomas P

    2016-11-15

    Conjugated polymer zwitterions (CPZs) are neutral, hydrophilic, polymer semiconductors. The pendent zwitterions, viewed as side chain dipoles, impart solubility in polar solvents for solution processing, and open opportunities as interfacial components of optoelectronic devices, for example, between metal electrodes and organic semiconductor active layers. Such interlayers are crucial for defining the performance of organic electronic devices, e.g., field-effect transistors (OFETs), light-emitting diodes (OLEDs), and photovoltaics (OPVs), all of which consist of multilayer structures. The interlayers reduce the Schottky barrier height and thus improve charge injection in OFETs and OLEDs. In OPVs, the interlayers serve to increase the built-in electric potential difference (Vbi) across the active layer, ensuring efficient extraction of photogenerated charge carriers. In general, polar and even charged electronically active polymers have gained recognition for their ability to modify metal/semiconductor interfaces to the benefit of organic electronics. While conjugated polyelectrolytes (CPEs) as interlayer materials are well-documented, open questions remain about the role of mobile counterions in CPE-containing devices. CPZs possess the processing advantages of CPEs, but as neutral molecules lack any potential complications associated with counterions. The electronic implications of CPZs on metal electrodes stem from the orientation of the zwitterion dipole moment in close proximity to the metal surface, and the resultant surface-induced polarization. This generates an interfacial dipole (Δ) at the CPZ/metal interface, altering the work function of the electrode, as confirmed by ultraviolet photoelectron spectroscopy (UPS), and improving device performance. An ideal cathode interlayer would reduce electrode work function, have orthogonal processability to the active layer, exhibit good film forming properties (i.e., wettability/uniformity), prevent exciton

  11. Catalyst-free "click" functionalization of polymer brushes preserves antifouling properties enabling detection in blood plasma.

    PubMed

    Parrillo, Viviana; de Los Santos Pereira, Andres; Riedel, Tomas; Rodriguez-Emmenegger, Cesar

    2017-06-08

    Progress in biosensors for clinical detection critically relies on modifications of the transducer surface to prevent non-specific adsorption from matrix components (i.e. antifouling) while supporting biomolecular recognition elements to capture the analyte. Such combination of properties presents a significant challenge. Hierarchically structured polymer brushes comprising an antifouling polymer bottom block and a functionalizable top block are proposed as a promising strategy to achieve this goal. We employed the catalyst-free strain-promoted alkyne-azide cycloaddition (SPAAC) "click" reaction to biofunctionalize antifouling polymer brushes without impairing their resistance to fouling. The functionalization was performed on the side chains along the top polymer block or only on the end-groups of the polymer brush. The immobilized amounts of bioreceptors (streptavidin followed by biotin-conjugated proteins) and the resistance to fouling from blood plasma of the surfaces obtained were evaluated via surface plasmon resonance. The end group functionalization approach resulted in very low immobilization of bioreceptor. On the other hand, the side group modification of a top polymer block led to immobilization of 83% of a monolayer of streptavidin. Following binding of a biotin-conjugated antibody (66 ng cm(-2)) the functionalized layer was able to reduce the fouling from undiluted human blood plasma by 89% in comparison with bare gold. Finally, the functionalized hierarchical polymer brushes were applied to the label-free detection of a model analyte in diluted human blood plasma, highlighting the potential for translation to medical applications. Copyright © 2017. Published by Elsevier B.V.

  12. Inkjet printed organic electrochemical transistors with highly conducting polymer electrolytes

    NASA Astrophysics Data System (ADS)

    Afonso, Mónica; Morgado, Jorge; Alcácer, Luís

    2016-10-01

    Organic Electrochemical Transistors (OECTs) were fabricated with two kinds of highly conducting polymer electrolytes, one with cations of small dimensions (Li+) and the other with cations of large dimensions (1-ethyl-3-methylimidazolium, EMI+). All OECTs exhibit transconductance values in the millisiemens range. Those with the larger EMI+ cations reach higher transconductance values and the saturated region of their I(V) characteristics extends to drain negative voltages of the order of -2 V without breakdown. These OECTs aim at potential applications for which it is relevant to use a solid polymer electrolyte instead of an aqueous electrolyte, namely, for integration in complex devices or in sensors and transducers where the electrolyte film may act as a membrane to prevent direct contact of the active material (PEDOT:PSS) with the biological media. The choice of electrolytes with cations of disparate sizes aims at assessing the nature (Faradaic or capacitive) of the processes occurring at the electrolyte/channel interface. The results obtained are consistent with a Faradaic-based operation mechanism.

  13. Removal of total cyanide in coking wastewater during a coagulation process: significance of organic polymers.

    PubMed

    Shen, Jian; Zhao, He; Cao, Hongbin; Zhang, Yi; Chen, Yongsheng

    2014-02-01

    Whether a cationic organic polymer can remove more total cyanide (TCN) than a non-ionic organic polymer during the same flocculation system has not been reported previously. In this study, the effects of organic polymers with different charge density on the removal mechanisms of TCN in coking wastewater are investigated by polyferric sulfate (PFS) with a cationic organic polymer (PFS-C) or a non-ionic polymer (PFS-N). The coagulation experiments results show that residual concentrations of TCN (Fe(CN)6(3-)) after PFS-C flocculation (TCN < 0.2 mg/L) are much lower than that after PFS-N precipitation. This can be attributed to the different TCN removal mechanisms of the individual organic polymers. To investigate the roles of organic polymers, physical and structural characteristics of the flocs are analyzed by FT-IR, XPS, TEM and XRD. Owing to the presence of N+ in PFS-C, Fe(CN)6(3-) and negative flocs (Fe(CN)6(3-) adsorbed on ferric hydroxides) can be removed via charge neutralization and electrostatic patch flocculation by the cationic organic polymer. However, non-ionic N in PFS-N barely reacts with cyanides through sweeping or bridging, which indicates that the non-ionic polymer has little influence on TCN removal.

  14. Polymer-ultrathin graphite sheet-polymer composite structured flexible nonvolatile bistable organic memory devices

    NASA Astrophysics Data System (ADS)

    Ick Son, Dong; Shim, Jae Ho; Park, Dong Hee; Jung, Jae Hun; Lee, Jung Min; Park, Won Il; Kim, Tae Whan; Choi, Won Kook

    2011-07-01

    We present data, which were obtained before bending and after bending, for the electrical bistabilities, memory stabilities, and memory mechanisms of three-layer structured flexible bistable organic memory (BOM) devices, which were fabricated utilizing the ultrathin graphite sheets (UGS) sandwiched between insulating poly(methylmethacrylate) (PMMA) polymer layers. The UGS were formed by transferring UGS (about 30 layers) and using a simple spin-coating technique. Transmission electron microscopy (TEM) measurements were performed to investigate the microstructural properties of the PMMA/UGS/PMMA films. Current-voltage (I-V) measurements were carried out to investigate the electrical properties of the BOM devices containing the UGS embedded in the PMMA polymer. Current-time (I-t) and current-cycle measurements under flat and bent conditions were performed to investigate the memory stabilities of the BOM devices. The memory characteristics of the BOM maintained similar device efficiencies after bending and were stable during repeated bendings of the BOM devices. The mechanisms for these characteristics of the fabricated BOM are described on the basis of the I-V results.

  15. Polymer mat prepared via Forcespinning™ as a SERS platform for immobilization and detection of bacteria from blood plasma.

    PubMed

    Witkowska, Evelin; Szymborski, Tomasz; Kamińska, Agnieszka; Waluk, Jacek

    2017-02-01

    One of potential applications of nano- and microscale polymer fibers is SERS-active platforms for the detection of biological compounds and microorganisms. This paper demonstrates the polymer mat obtained with Forcespinning™ technique used to detect the bacteria from blood plasma. Forcespinning™ is a new method of manufacturing of polymer fibers which can be applied to variety of polymer materials, e.g. polyethylene, nylon, PA6 and others. The method is based on the centrifugal force to draw fiber from molten polymer, which allows tuning the diameter of the fiber from tens of nanometers up to micrometers. Wide range of diameters makes the forcespun polymer mat an excellent material to filter bacteria from fluids (e.g. blood plasma, water). Covering the mat with Au:Ag alloy turns it into a SERS platform able to immobilize, detect, and identify bacteria. We provide proof-of-concept, showing detection of S. aureus, P. aeruginosa, and S. Typhimurium from blood plasma.

  16. Protein immobilization capacity and covalent binding coverage of pulsed plasma polymer surfaces

    NASA Astrophysics Data System (ADS)

    Yin, Yongbai; Bax, Daniel; McKenzie, David R.; Bilek, Marcela M. M.

    2010-06-01

    Three carbon surfaces were deposited using pulsed plasma enhanced chemical vapour deposition method: a low and a high nitrogen-containing plasma polymer surfaces and a diamond-like carbon surface. The surfaces were analysed using both X-ray photoelectron spectroscopy (XPS) technique and the enzyme-linked immunosorbent assay (ELISA) method combining with sodium dodecyl sulphate (SDS) cleaning to investigate the capacity and covalent binding of the immobilized proteins. A good correlation was found on quantification of remaining protein after SDS cleaning using the ELISA method and the XPS technique. All surfaces had similar initial capacity of protein attachment but with large different resistance to SDS cleaning. The analysis showed that the high nitrogen-containing plasma polymer was the best biocompatible material due to its highest resistance to SDS cleaning, i.e. with the highest quantity (˜80%) of proteins bound covalently.

  17. Plasma treatment process for palladium chemisorption onto polymers before electroless deposition

    SciTech Connect

    Charbonnier, M.; Alami, M.; Romand, M.

    1996-02-01

    Before electroless plating, polymer surfaces must be sensitized and/or activated by using either the conventional two-step or one-step process. The latter stage is a compulsory one to make such surfaces catalytic, e.g., for Ni-P deposition. These processes are performed here using O{sub 2}, NH{sub 3}, or N{sub 2} plasma pretreatments. Reaction mechanisms are proposed for each of the processes and for each type of surface considered (oxygenated or both oxygenated and nitrogenated by the plasma treatment). Direct palladium chemisorption onto nitrogenated groups is highlighted. This allows one to simplify the process making the surface catalytic via elimination of the use of SnCl{sub 2} and to extend the method to any polymer. An additional interest of the plasma treatments, besides their high efficiency in grafting chemical functions, is to perform this grafting at will on selected areas which results in selective metallization.

  18. "Thunderstruck": Plasma-Polymer-Coated Porous Silicon Microparticles As a Controlled Drug Delivery System.

    PubMed

    McInnes, Steven J P; Michl, Thomas D; Delalat, Bahman; Al-Bataineh, Sameer A; Coad, Bryan R; Vasilev, Krasimir; Griesser, Hans J; Voelcker, Nicolas H

    2016-02-01

    Controlling the release kinetics from a drug carrier is crucial to maintain a drug's therapeutic window. We report the use of biodegradable porous silicon microparticles (pSi MPs) loaded with the anticancer drug camphothecin, followed by a plasma polymer overcoating using a loudspeaker plasma reactor. Homogenous "Teflon-like" coatings were achieved by tumbling the particles by playing AC/DC's song "Thunderstruck". The overcoating resulted in a markedly slower release of the cytotoxic drug, and this effect correlated positively with the plasma polymer coating times, ranging from 2-fold up to more than 100-fold. Ultimately, upon characterizing and verifying pSi MP production, loading, and coating with analytical methods such as time-of-flight secondary ion mass spectrometry, scanning electron microscopy, thermal gravimetry, water contact angle measurements, and fluorescence microscopy, human neuroblastoma cells were challenged with pSi MPs in an in vitro assay, revealing a significant time delay in cell death onset.

  19. PLASMA COAGULATION BY ORGANISMS OTHER THAN STAPHYLOCOCCUS AUREUS.

    PubMed

    BAYLISS, B G; HALL, E R

    1965-01-01

    Bayliss, Berenice G. (Washington State University, Pullman), and Elizabeth R. Hall. Plasma coagulation by organisms other than Staphylococcus aureus. J. Bacteriol. 89:101-105. 1965.-Approximately 200 organisms were investigated for their ability to clot human and rabbit plasma. Various anticoagulants were used in preparing the plasma: acid-citrate-dextrose, ethylenediaminetetraacetate, balanced oxalate, potassium and sodium oxalates, and heparin. Twelve organisms were found which coagulated citrated plasma in less than 8 hr: four strains of Streptococcus faecalis; two strains of S. faecalis var. zymogenes; three strains of S. faecalis var. liquefaciens; and one strain each of S. pyogenes, Escherichia coli, and Serratia marcescens. Six strains of coagulase-positive Staphylococcus were selected for use as controls. Experiments were performed to determine the mechanism by which these microorganisms coagulated citrated plasma. As this was the only plasma clotted, it was presumed that the citrate was utilized by the microorganisms, thereby releasing the calcium which was then made available so that normal physiological clotting could occur. To test this hypothesis, a chromatographic method was employed to determine the presence or absence of citrate. Coagulation tests, by use of increasing amounts of citrate, showed a linear relationship between the amount of citrate in the plasma and the coagulation time. It was demonstrated that the organisms must be actively metabolizing to clot citrated plasma. Proof for this was obtained by using a cell-free filtrate, to which thimerosal had been added to inhibit growth, instead of whole cultures for the coagulation test. Only the coagulase-positive staphylococci coagulated the citrated plasma under these conditions. From the results obtained, it was concluded that plasma coagulation by these organisms was by citrate utilization.

  20. 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.

  1. Modification of the texture of a polymer material surface in dust plasma

    NASA Astrophysics Data System (ADS)

    Karasev, V. Yu.; Dzlieva, E. S.; Gorbenko, A. P.; Mashek, I. Ch.; Polishchuk, V. A.; Mironova, I. I.

    2017-03-01

    We have analyzed the modification of the texture of polymer particle surface in a dust plasma. Monodisperse spherical melamine formaldehyde particles were injected into the glow discharge plasma in neon. At a certain discharge current and gas pressure in the discharge tube, the particles were suspended in dust-plasma traps and experienced the action of the plasma of 5-25 min. Then, the particles were extracted and the collected material was studied using the scanning electron microscope. Among the results, a change in the diameter and roughness of the surface depending on the residence time of particles in the dust plasma was established. It was found that the absolute deviation of all points of the surface profile averaged over the evaluation length were in the nanometer range. The time of complete degradation of particles in the experimental conditions has been established.

  2. Temperature-responsive enzyme-polymer nanoconjugates with enhanced catalytic activities in organic media.

    PubMed

    Zhu, Jingying; Zhang, Yifei; Lu, Diannan; Zare, Richard N; Ge, Jun; Liu, Zheng

    2013-07-11

    A general approach for preparing enzyme-polymer nanoconjugates that respond to temperature in organic media is presented. These nanoconjugates readily dissolve in organic solvents for homogenous catalysis at 40 °C and showed greatly enhanced apparent catalytic activities. The recovery of the soluble enzyme-polymer nanoconjugates is accomplished by temperature-induced precipitation.

  3. 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.

  4. Quartz crystal microbalance sensor for organic vapor detection based on molecularly imprinted polymers.

    PubMed

    Fu, Yi; Finklea, Harry O

    2003-10-15

    Molecularly imprinted polymers on quartz crystal microbalances (QCM) are examined for their ability to detect vapors of small organic molecules with greater sensitivity and selectivity than the traditional amorphous polymer coatings. Hydroquinone and phenol serve as noncovalently bound templates that generate shape-selective cavities in a poly(acrylic) or poly(methacrylic) polymer matrix. The imprinted polymers are immobilized on the piezoelectric crystal surface via a precoated poly(isobutylene) layer. The behavior of the imprinted polymer films is characterized by the dynamic and steady-state response of the QCM frequency to pulses of organic vapors in dry air. The apparent partition coefficients are determined for imprinted and nonimprinted polymers prepared by two synthetic methods and for varying mole ratios of template to monomer. The hydroquinone-imprinted polymers and, to a lesser extent, the phenol-imprinted polymers exhibit greater sensitivity and higher selectivity than the nonimprinted polymers toward organic vapors that are structurally related to the templates. These results indicate that molecularly imprinted polymers are promising for the development of selective piezoelectric sensors for organic vapor detection.

  5. Laser induced micro plasma processing of polymer substrates for biomedical implant applications

    NASA Astrophysics Data System (ADS)

    French, P. W.; Rosowski, A.; Murphy, M.; Irving, M.; Sharp, M. C.

    2015-07-01

    This paper reports the experimental results of a new hybrid laser processing technique; Laser Induced Micro Plasma Processing (LIMP2). A transparent substrate is placed on top of a medium that will interact with the laser beam and create a plasma. The plasma and laser beam act in unison to ablate material and create micro-structuring on the "backside" of the substrate. We report the results of a series of experiments on a new laser processing technique that will use the same laser-plasma interaction to micromachining structures into glass and polymer substrates on the "topside" of the substrate and hence machine non-transparent material. This new laser processing technique is called Laser Induced Micro Plasma Processing (LIMP2). Micromachining of biomedical implants is proving an important enabling technology in controlling cell growth on a macro-scale. This paper discusses LIMP2 structuring of transparent substrate such as glasses and polymers for this application. Direct machining of these materials by lasers in the near infrared is at present impossible. Laser Induced Micro Plasma Processing (LIMP2) is a technique that allows laser operating at 1064 nm to machine microstructures directly these transparent substrates.

  6. Synthesis of highly functionalised plasma polymer films from protonated precursor ions via the plasma α-γ transition.

    PubMed

    Saboohi, Solmaz; Coad, Bryan R; Griesser, Hans J; Michelmore, Andrew; Short, Robert D

    2017-02-15

    Chemically functionalized surfaces may be produced via plasma polymerization, however a high degree of functional group retention is often difficult to achieve. Here, the plasma polymerization of three structurally related ester precursors, ethyl isobutyrate (EIB), methyl isobutyrate (MIB) and ethyl trimethylacetate (ETMA) is compared at low and high pressure. In moving from a low pressure to higher pressure regime, significant changes in the plasma chemistry and resulting plasma polymer deposit were observed with much higher retention of chemical functionality at the higher pressure observed. Until now these changes would have been attributed to a decrease in the energy/molecule, however we show by direct measurement of the chemistry and physics of the plasma that there is fundamental shift in the properties of the plasma and surface interactions which explain the results. At low pressure (α regime) precursor fragmentation and neutral deposition dominate resulting in poor functional group retention. Increasing the pressure such that the sheath region close to surfaces becomes collisional (γ regime) favours production of protonated precursor ions which retain functionality and dominate the deposition process rather than radical species.

  7. 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.

  8. 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

  9. Nanoscale Fluorescent Metal-Organic Framework@Microporous Organic Polymer Composites for Enhanced Intracellular Uptake and Bioimaging.

    PubMed

    Wang, Lei; Wang, Weiqi; Zheng, Xiaohua; Li, Zhensheng; Xie, Zhigang

    2017-01-26

    Polymer-modified metal-organic frameworks combine the advantages of both soft polymers and crystalline metal-organic frameworks (MOFs). It is a big challenge to develop simple methods for surface modification of MOFs. In this work, MOF@microporous organic polymer (MOP) hybrid nanoparticles (UNP) have been synthesized by epitaxial growth of luminescent boron-dipyrromethene (BODIPYs)-imine MOPs on the surface of UiO-MOF seeds, which exhibit low cytotoxicity, smaller size distribution, well-retained pore integrity, and available functional sites. After folic acid grafting, the enhanced intracellular uptake and bioimaging was validated. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Plasma-etched organic layers for antireflection purposes.

    PubMed

    Schulz, Ulrike; Präfke, Christiane; Gödeker, Christoph; Kaiser, Norbert; Tünnermann, Andreas

    2011-03-20

    Organic layers can be used to realize special functions in optical interference coatings. Suitable compounds for such layers were thermally evaporated and characterized. A plasma etching procedure was applied to produce nanostructures on top of the organic layers to reduce their effective refractive indices. Broadband antireflective coatings were obtained by combining these artificial low-index layers with conventionally prepared interference stacks.

  11. Investigation of Carrier Collection Capability in Organic Heterostructure with Conductive Polymer Nanofiber

    NASA Astrophysics Data System (ADS)

    Yamashita, Kenichi; Maeda, Tatsuya; Kusakabe, Youhei; Kotaki, Masaya

    2011-08-01

    The capability of carrier collection was investigated for an organic heterointerface with conductive polymer nanofibers and a fullerene derivative. The electrospinning method was employed for fabricating conductive polymer nanofibers. In a photovoltaic device with this heterointerface, a rather large photocurrent was obtained in spite of the fact that the polymer nanofibers were large at submicrometer diameter. It was considered that conductive polymer nanofibers can serve as a conduction path for photoinduced carriers and might be helpful for the marked improvement in power conversion efficiency of organic thin film solar cell.

  12. 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.

  13. Laser initiation and decay processes in an organic vapor plasma

    NASA Astrophysics Data System (ADS)

    Ding, Guowen

    A large volume organic molecular plasma (hundreds of cm3) is created by a 193 nm laser ionizing an organic molecule, Tetrakis-(dimethylamino)-ethylene (TMAE). The plasma is found to be characterized by high electron density (10 13-1011cm-3), low electron temperature (~0.1 eV), fast creation (~10 ns) and rapid decaying (electron-ion recombination coefficient ~10-6 cm3/s). Fast Langmuir probe (LP) techniques are developed for diagnosing this plasma, including a novel probe design and fabrication, a fast detection system, sampling, indirect probe heating, electro-magnetic shielding and dummy probe techniques. Plasma physical processes regarding fast LP diagnostics for different time scales (t> and <100 ns) are studied. A theory for the correction due to a rapidly decaying plasma to LP measurements is developed. The mechanisms responsible for the plasma decay are studied, and a delayed ionization process is found to be important in interpreting the decay processes. It is also found that nitrogen can enhance the delayed emission of a TMAE Rydberg state from the TMAE plasma. This result strongly suggests that a long-lifetime highly-excited state is important in the TMAE plasma decay process. This result supports the delayed ionization mechanism. A model combining electron-ion recombination and delayed ionization processes is developed to calculate the delayed ionization lifetime.

  14. Oxygen plasma-treated thermoresponsive polymer surfaces for cell sheet engineering.

    PubMed

    Shimizu, Kazunori; Fujita, Hideaki; Nagamori, Eiji

    2010-06-01

    Although cell sheet tissue engineering is a potent and promising method for tissue engineering, an increase of mechanical strength of a cell sheet is needed for easy manipulation of it during transplantation or 3D tissue fabrication. Previously, we developed a cell sheet-polymer film complex that had enough mechanical strength that can be manipulated even by tweezers (Fujita et al., 2009. Biotechnol Bioeng 103(2): 370-377). We confirmed the polymer film involving a temperature sensitive polymer and extracellular matrix (ECM) proteins could be removed by lowering temperature after transplantation, and its potential use in regenerative medicine was demonstrated. However, the use of ECM proteins conflicted with high stability in long-term storage and low cost. In the present study, to overcome these drawbacks, we employed the oxygen plasma treatment instead of using the ECM proteins. A cast and dried film of thermoresponsive poly-N-isopropylacrylamide (PNIPAAm) was fabricated and treated with high-intensity oxygen plasma. The cells became possible to adhere to the oxygen plasma-treated PNIPAAm surface, whereas could not to the inherent surface of bulk PNIPAAm without treatment. Characterizations of the treated surface revealed the surface had high stability. The surface roughness, wettability, and composition were changed, depending on the plasma intensity. Interestingly, although bulk PNIPAAm layer had thermoresponsiveness and dissolved below lower critical solution temperature (LCST), it was found that the oxygen plasma-treated PNIPAAm surface lost its thermoresponsiveness and remained insoluble in water below LCST as a thin layer. Skeletal muscle C2C12 cells could be cultured on the oxygen plasma-treated PNIPAAm surface, a skeletal muscle cell sheet with the insoluble thin layer could be released in the medium, and thus the possibility of use of the cell sheet for transplantation was demonstrated.

  15. 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.

  16. Nitrogen plasma-implanted titanium as bipolar plates in polymer electrolyte membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Feng, Kai; Kwok, Dixon T. K.; Liu, Dongan; Li, Zhuguo; Cai, Xun; Chu, Paul K.

    Nitrogen plasma immersion ion implantation (PIII), a non-line-of-sight surface treatment technique suitable for bipolar plates in polymer electrolyte membrane fuel cells, is conducted at low and high temperature to improve the corrosion resistance and conductivity of titanium sheets. X-ray photoelectron spectroscopy (XPS) shows that high-temperature (HT) nitrogen PIII produces a thick oxy-nitride layer on the titanium surface. This layer which provides good corrosion resistance and high electrical conductivity as verified by electrochemical tests, inductively coupled plasma optical emission spectroscopy, and interfacial contact resistance (ICR) measurements renders the materials suitable for polymer electrolyte membrane fuel cells. In comparison, the low-temperature (LT) PIII titanium sample exhibits poorer corrosion resistance and electrical conductivity than the untreated titanium control.

  17. Through-thickness plasma modification of biodegradable and nonbiodegradable porous polymer constructs.

    PubMed

    Safinia, Laleh; Wilson, Karen; Mantalaris, Athanasios; Bismarck, Alexander

    2008-12-01

    Pure poly(lactide-co-glycolide) and polystyrene surfaces are not very suitable to support cell adhesion/spreading owing to their hydrophobic nature and low surface energy. The interior surfaces of large porous 3D scaffolds were modified and activated using radio-frequency, low-pressure air plasma. An increase in the wettability of the surface was observed after exposure to air plasma, as indicated by the decrease in the contact angles of the wet porous system. The surface composition of the plasma-treated polymers was studied using X-ray photoelectron spectroscopy. pH-dependent zeta-potential measurements confirm the presence of an increased number of functional groups. However, the plasma-treated surfaces have a less acidic character than the original polymer surfaces as seen by a shift in their isoelectric point. Zeta-potential, as well as contact angle measurements, on 3D scaffolds confirm that plasma treatment is a useful tool to modify the surface properties throughout the interior of large scaffolds. (c) 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008.

  18. 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.

  19. 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.

  20. Plasma Diagnostics for Plasma Polymer Coatings Used in Fabrication of Thin Wall CH Shells for Direct Drive OMEGA Cryogenic Experiments

    NASA Astrophysics Data System (ADS)

    Ross, P.; Nikroo, A.; Czechowicz, D.; Dicken, M.

    2002-11-01

    High aspect ratio CH shells, 1 μm thick, 9001 μm diameter, are crucial for the success of the cryogenic direct drive inertial confinement fusion (ICF) experiments at the OMEGA laser facility at the University of Rochester's Laboratory for Laser Energetics (LLE). Plasma polymer coatings are currently used in fabrication of such shells, which can be made substantially stronger by altering parameters. High strength is important for inherently fragile high aspect ratio shells. The plasma characteristics used in the deposition process were studied in order to determine a correlation between the plasma parameters and the strength of shells. Several plasma processing parameters such as deposition pressure, power and relative and absolute gas flow rates were varied. The plasma was studied using several techniques such as optical emission spectroscopy, Langmuir probe diagnostics, and mass spectrometry. These diagnostic results were then correlated with direct measurements of the target strength (burst testing and buckle testing) and permeability to determine the ideal parameters for creating the strongest and most permeable ICF targets.

  1. Dissolved organic nitrogen removal during water treatment by aluminum sulfate and cationic polymer coagulation.

    PubMed

    Lee, Wontae; Westerhoff, Paul

    2006-12-01

    Coagulation of three surface waters was conducted with aluminum salt and/or cationic polymer to assess dissolved organic nitrogen (DON) removal. Coagulation with aluminum sulfate removed equal or slightly lower amounts of DON as compared to dissolved organic carbon (DOC). At aluminum sulfate dosages up to 5mg per mg DOC, the cationic polymer improved DON removal by an additional 15% to 20% over aluminum sulfate alone. At very high aluminum sulfate dosages (>8 mg aluminum sulfate per mg DOC), however, the cationic polymer addition negligibly increased DON removal. Molecular weight fractionation before and after coagulation experiments indicated that cationic polymer addition can increase the removal of all molecular weight fractions of DON with the highest molecular weight fraction (>10,000 Da) being preferentially removed. Results indicated that the DON added as part of the cationic polymer was almost completely removed at optimum aluminum sulfate and polymer doses.

  2. 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.

  3. 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.

  4. Model polymer etching and surface modification by a time modulated RF plasma jet: role of atomic oxygen and water vapor

    NASA Astrophysics Data System (ADS)

    Luan, P.; Knoll, A. J.; Wang, H.; Kondeti, V. S. S. K.; Bruggeman, P. J.; Oehrlein, G. S.

    2017-01-01

    The surface interaction of a well-characterized time modulated radio frequency (RF) plasma jet with polystyrene, poly(methyl methacrylate) and poly(vinyl alcohol) as model polymers is investigated. The RF plasma jet shows fast polymer etching but mild chemical modification with a characteristic carbonate ester and NO formation on the etched surface. By varying the plasma treatment conditions including feed gas composition, environment gaseous composition, and treatment distance, we find that short lived species, especially atomic O for Ar/1% O2 and 1% air plasma and OH for Ar/1% H2O plasma, play an essential role for polymer etching. For O2 containing plasma, we find that atomic O initiates polymer etching and the etching depth mirrors the measured decay of O atoms in the gas phase as the nozzle-surface distance increases. The etching reaction probability of an O atom ranging from 10-4 to 10-3 is consistent with low pressure plasma research. We also find that adding O2 and H2O simultaneously into Ar feed gas quenches polymer etching compared to adding them separately which suggests the reduction of O and OH density in Ar/O2/H2O plasma.

  5. Porous Organic Polymers for Post-Combustion Carbon Capture.

    PubMed

    Zou, Lanfang; Sun, Yujia; Che, Sai; Yang, Xinyu; Wang, Xuan; Bosch, Mathieu; Wang, Qi; Li, Hao; Smith, Mallory; Yuan, Shuai; Perry, Zachary; Zhou, Hong-Cai

    2017-10-01

    One of the most pressing environmental concerns of our age is the escalating level of atmospheric CO2 . Intensive efforts have been made to investigate advanced porous materials, especially porous organic polymers (POPs), as one type of the most promising candidates for carbon capture due to their extremely high porosity, structural diversity, and physicochemical stability. This review provides a critical and in-depth analysis of recent POP research as it pertains to carbon capture. The definitions and terminologies commonly used to evaluate the performance of POPs for carbon capture, including CO2 capacity, enthalpy, selectivity, and regeneration strategies, are summarized. A detailed correlation study between the structural and chemical features of POPs and their adsorption capacities is discussed, mainly focusing on the physical interactions and chemical reactions. Finally, a concise outlook for utilizing POPs for carbon capture is discussed, noting areas in which further work is needed to develop the next-generation POPs for practical applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Ambient low temperature plasma etching of polymer films for secondary ion mass spectrometry molecular depth profiling.

    PubMed

    Muramoto, Shin; Staymates, Matthew E; Brewer, Tim M; Gillen, Greg

    2012-12-18

    The feasibility of a low temperature plasma (LTP) probe as a way to prepare polymer bevel cross sections for secondary ion mass spectrometry (SIMS) applications was investigated. Poly(lactic acid) and poly(methyl methacrylate) films were etched using He LTP, and the resulting crater walls were depth profiled using time-of-flight secondary ion mass spectrometry (ToF-SIMS) to examine changes in chemistry over the depth of the film. ToF-SIMS results showed that while exposure to even 1 s of plasma resulted in integration of atmospheric nitrogen and contaminants to the newly exposed surface, the actual chemical modification to the polymer backbone was found to be chemistry-dependent. For PLA, sample modification was confined to the top 15 nm of the PLA surface regardless of plasma exposure dose, while measurable change was not seen for PMMA. The confinement of chemical modification to 15 nm or less of the top surface suggests that LTP can be used as a simple method to prepare cross sections or bevels of polymer thin films for subsequent analysis by surface-sensitive molecular depth profiling techniques such as SIMS, X-ray photoelectron spectroscopy (XPS), and other spatially resolved mass spectrometric techniques.

  7. Electrochemical route to fabricate film-like conjugated microporous polymers and application for organic electronics.

    PubMed

    Gu, Cheng; Chen, Youchun; Zhang, Zhongbo; Xue, Shanfeng; Sun, Shuheng; Zhang, Kai; Zhong, Chengmei; Zhang, Huanhuan; Pan, Yuyu; Lv, Ying; Yang, Yanqin; Li, Fenghong; Zhang, Suobo; Huang, Fei; Ma, Yuguang

    2013-07-05

    Film-like conjugated microporous polymers (CMPs) are fabricated by the novel strategy of carbazole-based electropolymerization. The CMP film storing a mass of counterions acting as an anode interlayer provides a significant power-conversion efficiency of 7.56% in polymer solar cells and 20.7 cd A(-1) in polymer light-emitting diodes, demonstrating its universality and potential as an electrode interlayer in organic electronics.

  8. Polymers of intrinsic microporosity (PIMs): organic materials for membrane separations, heterogeneous catalysis and hydrogen storage.

    PubMed

    McKeown, Neil B; Budd, Peter M

    2006-08-01

    This tutorial review describes recent research directed towards the synthesis of polymer-based organic microporous materials termed Polymers of Intrinsic Microporosity (PIMs). PIMs can be prepared either as insoluble networks or soluble polymers with both types giving solids that exhibit analogous behaviour to that of conventional microporous materials such as activated carbons. Soluble PIMs may be processed into thin films for use as highly selective gas separation membranes. Preliminary results also demonstrate the potential of PIMs for heterogeneous catalysis and hydrogen storage.

  9. Donor polymer design enables efficient non-fullerene organic solar cells

    PubMed Central

    Li, Zhengke; Jiang, Kui; Yang, Guofang; Lai, Joshua Yuk Lin; Ma, Tingxuan; Zhao, Jingbo; Ma, Wei; Yan, He

    2016-01-01

    To achieve efficient organic solar cells, the design of suitable donor–acceptor couples is crucially important. State-of-the-art donor polymers used in fullerene cells may not perform well when they are combined with non-fullerene acceptors, thus new donor polymers need to be developed. Here we report non-fullerene organic solar cells with efficiencies up to 10.9%, enabled by a novel donor polymer that exhibits strong temperature-dependent aggregation but with intentionally reduced polymer crystallinity due to the introduction of a less symmetric monomer unit. Our comparative study shows that an analogue polymer with a C2 symmetric monomer unit yields highly crystalline polymer films but less efficient non-fullerene cells. Based on a monomer with a mirror symmetry, our best donor polymer exhibits reduced crystallinity, yet such a polymer matches better with small molecular acceptors. This study provides important insights to the design of donor polymers for non-fullerene organic solar cells. PMID:27782112

  10. Donor polymer design enables efficient non-fullerene organic solar cells.

    PubMed

    Li, Zhengke; Jiang, Kui; Yang, Guofang; Lai, Joshua Yuk Lin; Ma, Tingxuan; Zhao, Jingbo; Ma, Wei; Yan, He

    2016-10-26

    To achieve efficient organic solar cells, the design of suitable donor-acceptor couples is crucially important. State-of-the-art donor polymers used in fullerene cells may not perform well when they are combined with non-fullerene acceptors, thus new donor polymers need to be developed. Here we report non-fullerene organic solar cells with efficiencies up to 10.9%, enabled by a novel donor polymer that exhibits strong temperature-dependent aggregation but with intentionally reduced polymer crystallinity due to the introduction of a less symmetric monomer unit. Our comparative study shows that an analogue polymer with a C2 symmetric monomer unit yields highly crystalline polymer films but less efficient non-fullerene cells. Based on a monomer with a mirror symmetry, our best donor polymer exhibits reduced crystallinity, yet such a polymer matches better with small molecular acceptors. This study provides important insights to the design of donor polymers for non-fullerene organic solar cells.

  11. A two-dimensional polymer prepared by organic synthesis.

    PubMed

    Kissel, Patrick; Erni, Rolf; Schweizer, W Bernd; Rossell, Marta D; King, Benjamin T; Bauer, Thomas; Götzinger, Stephan; Schlüter, A Dieter; Sakamoto, Junji

    2012-02-05

    Synthetic polymers are widely used materials, as attested by a production of more than 200 millions of tons per year, and are typically composed of linear repeat units. They may also be branched or irregularly crosslinked. Here, we introduce a two-dimensional polymer with internal periodicity composed of areal repeat units. This is an extension of Staudinger's polymerization concept (to form macromolecules by covalently linking repeat units together), but in two dimensions. A well-known example of such a two-dimensional polymer is graphene, but its thermolytic synthesis precludes molecular design on demand. Here, we have rationally synthesized an ordered, non-equilibrium two-dimensional polymer far beyond molecular dimensions. The procedure includes the crystallization of a specifically designed photoreactive monomer into a layered structure, a photo-polymerization step within the crystal and a solvent-induced delamination step that isolates individual two-dimensional polymers as free-standing, monolayered molecular sheets.

  12. Fouling of microfiltration membranes by organic polymer coagulants and flocculants: controlling factors and mechanisms.

    PubMed

    Wang, Sen; Liu, Charles; Li, Qilin

    2011-01-01

    Organic polymers are commonly used as coagulants or flocculants in pretreatment for microfiltration (MF). These high molecular weight compounds are potential membrane foulants when carried over to the MF filters. This study examined fouling of three MF membranes of different materials by three commonly used water treatment polymers: poly(diallyldimethylammonium) chloride (pDADMAC), polyacrylamide (PAM), and poly(acrylic acid-co-acrylamide (PACA) with a wide range of molecular weights. The effects of polymer molecular characteristics, membrane surface properties, solution condition and polymer concentration on membrane fouling were investigated. Results showed severe fouling of microfiltration membranes at very low polymer concentrations, suggesting that residual polymers carried over from the coagulation/flocculation basin can contribute significantly to membrane fouling. The interactions between polymers and membranes depended strongly on the molecular size and charge of the polymer. High molecular weight, positively charged polymers caused the greatest fouling. Blockage of membrane pore openings was identified as the main fouling mechanism with no detectable internal fouling in spite of the small molecular size of the polymers relative to the membrane pore size. Solution conditions (e.g., pH and calcium concentration) that led to larger polymer molecular or aggregate sizes resulted in greater fouling.

  13. Surface modification of polymers by atomic oxygen using ECR plasma

    NASA Astrophysics Data System (ADS)

    Abdul majeed, Riyadh M. A.; Datar, A.; Bhoraskar, S. V.; Bhoraskar, V. N.

    2007-05-01

    Polyimide (PI) and fluorinated ethylene propylene (FEP) samples were exposed to atomic oxygen ions of average energy ˜12 eV and flux ˜5 × 10 13 ions cm -2 s -1, produced in an ECR plasma. The fluence of the oxygen ions was varied from sample to sample over a range from ˜5 × 10 16 to 2 × 10 17 ions cm -2. The pre- and the post-irradiated samples were characterized by the contact angle, AFM and XPS techniques. The results indicate that the surface roughness of the polyimide increased from ˜7 to ˜65 nm, that of the FEP from ˜5 to ˜28 nm and the surface regions of both polyimide and FEP changed from hydrophobic to hydrophilic after exposure to atomic oxygen ions. The XPS results reveal that the concentrations of carbon, fluorine and oxygen changed even at a fluence of ˜10 17 ions cm -2 of the atomic oxygen ions. The results of the present study reveal that significant changes have been induced in the surface morphology and adhesion properties of polyimide and FEP after exposure to atomic oxygen ions.

  14. Early Stage Expansion and Time-Resolved Spectral Emission of Laser-Induced Plasma from Polymer

    DTIC Science & Technology

    2009-01-01

    thus its interaction with ambient air. These influences can significantly alter spectral emission of the plasma. For organic samples especially...to the analysis of organic materials. In this paper, we report observations of early stage expansion and interaction with ambient air of the plasma...ablation interaction is absent. Subsequent to the early stage expansion, we observe for each studied ablation regime, spectral emission from CN, a typical

  15. 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.

  16. Micro-pixel array of organic light-emitting diodes applying imprinting technique with a polymer replica

    NASA Astrophysics Data System (ADS)

    Park, Tae Hyun; Kim, Young Min; Park, Young Wook; Choi, Jin Hwan; Jeong, Jin-Wook; Dong, Ki Young; Choi, Kyung Cheol; Ju, Byeong-Kwon

    2009-08-01

    Efficient micro-pixel array of small molecule organic light-emitting diodes (OLEDs) has been fabricated by an imprinting technique which uses a polymer replica. To confirm the effect of the oxygen plasma for removing the residual layer, the performance of two kinds of OLEDs with varying thicknesses of resin as the micro-pixel array, have been compared. The measured results of the OLEDs have shown comparable device performances that are significantly characterized depending on the residues on the substrate. The performance of enhanced device has achieved efficiencies of 3.6 cd/A and 1.9 lm/W at 20 mA/cm2.

  17. 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.

  18. 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.

  19. Formation of nanocrystalline diamond in polymer like carbon films deposited by plasma CVD.

    PubMed

    Bhaduri, A; Chaudhuri, P

    2009-09-01

    Conventional plasma enhanced chemical vapour deposition (PECVD) method is generally not suitable for the growth of nanocrystalline diamond (NCD) films. However, our study shows that conditions favourable for powder formation help to grow large amount of nanocrystallites in conventional PECVD. With CH4 as the carbon source gas, dilution with Ar and moderate (50 W) rf power enhances formations of powders (nanoparticles) and C2 dimers within the plasma. On the other hand, with pure CH4 or with hydrogen diluted CH4, powder formation as also NCD growth is hindered. It is proposed that the nanoparticles formed in the plasma act as the "islands" while the C2 dimers are the "seeds" for the NCD growth. The structure of the films deposited on the grounded anode under different conditions of dilution has been studied. It is observed that with high Ar dilution the films contain NCD embedded in polymer like carbon (PLC) matrix.

  20. Ultrasonic spray coating polymer and small molecular organic film for organic light-emitting devices

    PubMed Central

    Liu, Shihao; Zhang, Xiang; Zhang, Letian; Xie, Wenfa

    2016-01-01

    Ultrasonic spray coating process (USCP) with high material -utilization, low manufacture costs and compatibility to streamline production has been attractive in researches on photoelectric devices. However, surface tension exists in the solvent is still a huge obstacle to realize smooth organic film for organic light emitting devices (OLEDs) by USCP. Here, high quality polymer anode buffer layer and small molecular emitting layer are successfully realized through USCP by introducing extra-low surface tension diluent and surface tension control method. The introduction of low surface tension methyl alcohol is beneficial to the formation of poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) films and brings obvious phase separation and improved conductivity to PEDOT:PSS film. Besides, a surface tension control method, in which new stable tension equilibrium is built at the border of wetting layer, is proposed to eliminate the effect of surface tension during the solvent evaporation stage of ultrasonic spray coating the film consists of 9,9-Spirobifluoren-2-yl-diphenyl-phosphine oxide doped with 10 wt% tris [2-(p -tolyl) pyridine] iridium (III). A smooth and homogenous small molecular emitting layer without wrinkles is successfully realized. The effectiveness of the ultrasonic spray coating polymer anode buffer layer and small molecular emitting layer are also proved by introducing them in OLEDs. PMID:27874030

  1. Ultrasonic spray coating polymer and small molecular organic film for organic light-emitting devices.

    PubMed

    Liu, Shihao; Zhang, Xiang; Zhang, Letian; Xie, Wenfa

    2016-11-22

    Ultrasonic spray coating process (USCP) with high material -utilization, low manufacture costs and compatibility to streamline production has been attractive in researches on photoelectric devices. However, surface tension exists in the solvent is still a huge obstacle to realize smooth organic film for organic light emitting devices (OLEDs) by USCP. Here, high quality polymer anode buffer layer and small molecular emitting layer are successfully realized through USCP by introducing extra-low surface tension diluent and surface tension control method. The introduction of low surface tension methyl alcohol is beneficial to the formation of poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) films and brings obvious phase separation and improved conductivity to PEDOT:PSS film. Besides, a surface tension control method, in which new stable tension equilibrium is built at the border of wetting layer, is proposed to eliminate the effect of surface tension during the solvent evaporation stage of ultrasonic spray coating the film consists of 9,9-Spirobifluoren-2-yl-diphenyl-phosphine oxide doped with 10 wt% tris [2-(p -tolyl) pyridine] iridium (III). A smooth and homogenous small molecular emitting layer without wrinkles is successfully realized. The effectiveness of the ultrasonic spray coating polymer anode buffer layer and small molecular emitting layer are also proved by introducing them in OLEDs.

  2. Ultrasonic spray coating polymer and small molecular organic film for organic light-emitting devices

    NASA Astrophysics Data System (ADS)

    Liu, Shihao; Zhang, Xiang; Zhang, Letian; Xie, Wenfa

    2016-11-01

    Ultrasonic spray coating process (USCP) with high material -utilization, low manufacture costs and compatibility to streamline production has been attractive in researches on photoelectric devices. However, surface tension exists in the solvent is still a huge obstacle to realize smooth organic film for organic light emitting devices (OLEDs) by USCP. Here, high quality polymer anode buffer layer and small molecular emitting layer are successfully realized through USCP by introducing extra-low surface tension diluent and surface tension control method. The introduction of low surface tension methyl alcohol is beneficial to the formation of poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) films and brings obvious phase separation and improved conductivity to PEDOT:PSS film. Besides, a surface tension control method, in which new stable tension equilibrium is built at the border of wetting layer, is proposed to eliminate the effect of surface tension during the solvent evaporation stage of ultrasonic spray coating the film consists of 9,9-Spirobifluoren-2-yl-diphenyl-phosphine oxide doped with 10 wt% tris [2-(p -tolyl) pyridine] iridium (III). A smooth and homogenous small molecular emitting layer without wrinkles is successfully realized. The effectiveness of the ultrasonic spray coating polymer anode buffer layer and small molecular emitting layer are also proved by introducing them in OLEDs.

  3. 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

  4. 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.

  5. 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...

  6. Mapping Polymer Donors toward High-Efficiency Fullerene Free Organic Solar Cells.

    PubMed

    Lin, Yuze; Zhao, Fuwen; Wu, Yang; Chen, Kai; Xia, Yuxin; Li, Guangwu; Prasad, Shyamal K K; Zhu, Jingshuai; Huo, Lijun; Bin, Haijun; Zhang, Zhi-Guo; Guo, Xia; Zhang, Maojie; Sun, Yanming; Gao, Feng; Wei, Zhixiang; Ma, Wei; Wang, Chunru; Hodgkiss, Justin; Bo, Zhishan; Inganäs, Olle; Li, Yongfang; Zhan, Xiaowei

    2017-01-01

    Five polymer donors with distinct chemical structures and different electronic properties are surveyed in a planar and narrow-bandgap fused-ring electron acceptor (IDIC)-based organic solar cells, which exhibit power conversion efficiencies of up to 11%.

  7. Materials chemistry: Organic polymers form fuel from water

    NASA Astrophysics Data System (ADS)

    Vyas, Vijay S.; Lotsch, Bettina V.

    2015-05-01

    Porous polymers have joined the ranks of light-activated catalysts that split water into hydrogen, a carbon-free alternative to fossil fuels. Their properties are easily tuned -- a big plus for the development of practically useful catalysts.

  8. Feasibility of Plasma Treated Clay in Clay/Polymer Nanocomposites Powders for use Laser Sintering (LS)

    NASA Astrophysics Data System (ADS)

    Almansoori, Alaa; Seabright, Ryan; Majewski, C.; Rodenburg, C.

    2017-05-01

    The addition of small quantities of nano-clay to nylon is known to improve mechanical properties of the resulting nano-composite. However, achieving a uniform dispersion and distribution of the clay within the base polymer can prove difficult. A demonstration of the fabrication and characterization of plasma-treated organoclay/Nylon12 nanocomposite was carried out with the aim of achieving better dispersion of clay platelets on the Nylon12 particle surface. Air-plasma etching was used to enhance the compatibility between clays and polymers to ensure a uniform clay dispersion in composite powders. Downward heat sintering (DHS) in a hot press is used to process neat and composite powders into tensile and XRD specimens. Morphological studies using Low Voltage Scanning Electron Microscopy (LV-SEM) were undertaken to characterize the fracture surfaces and clay dispersion in powders and final composite specimens. Thermogravimetric analysis (TGA) testing performed that the etched clay (EC) is more stable than the nonetched clay (NEC), even at higher temperatures. The influence of the clay ratio and the clay plasma treatment process on the mechanical properties of the nanocomposites was studied by tensile testing. The composite fabricated from (3% EC/N12) powder showed ~19 % improvement in elastic modulus while the composite made from (3% NEC/N12) powder was improved by only 14%). Most notably however is that the variation between tests is strongly reduced when etch clay is used in the composite. We attribute this to a more uniform distribution and better dispersion of the plasma treated clay within polymer powders and ultimately the composite.

  9. Plasma membrane organization and function: moving past lipid rafts.

    PubMed

    Kraft, Mary L

    2013-09-01

    "Lipid raft" is the name given to the tiny, dynamic, and ordered domains of cholesterol and sphingolipids that are hypothesized to exist in the plasma membranes of eukaryotic cells. According to the lipid raft hypothesis, these cholesterol- and sphingolipid-enriched domains modulate the protein-protein interactions that are essential for cellular function. Indeed, many studies have shown that cellular levels of cholesterol and sphingolipids influence plasma membrane organization, cell signaling, and other important biological processes. Despite 15 years of research and the application of highly advanced imaging techniques, data that unambiguously demonstrate the existence of lipid rafts in mammalian cells are still lacking. This Perspective summarizes the results that challenge the lipid raft hypothesis and discusses alternative hypothetical models of plasma membrane organization and lipid-mediated cellular function.

  10. 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

  11. Rational composition control of mixed-lanthanide metal-organic frameworks by an interfacial reaction with metal ion-doped polymer substrates

    NASA Astrophysics Data System (ADS)

    Tsuruoka, Takaaki; Miyanaga, Ayumi; Ohhashi, Takashi; Hata, Manami; Takashima, Yohei; Akamatsu, Kensuke

    2017-09-01

    A simple composition control route to mixed-lanthanide metal-organic frameworks (MOFs) was developed based on an interfacial reaction with mixed-lanthanide metal ion-doped polymer substrates. By controlling the composition of lanthanide ion (Eu3+ and Tb3+) dopants in polymer substrates to be used as metal ion precursors and scaffolding for the formation of MOFs, [EuxTb2-x(bdc)3(H2O)4]n crystals with a tunable metal composition could be routinely prepared on polymer substrates. Inductively coupled plasma (ICP) measurements revealed that the composition of the obtained frameworks was almost the same as that of the initial polymer substrates. In addition, the resulting [EuxTb2-x(bdc)3(H2O)4]n crystals showed strong phosphorescence because of Eu3+ transitions, indicating that the energy transfer from Tb3+ to Eu3+ ions in the frameworks could be achieved with high efficiency.

  12. Unraveling atomic-level self-organization at the plasma-material interface

    NASA Astrophysics Data System (ADS)

    Allain, J. P.; Shetty, A.

    2017-07-01

    The intrinsic dynamic interactions at the plasma-material interface and critical role of irradiation-driven mechanisms at the atomic scale during exposure to energetic particles require a priori the use of in situ surface characterization techniques. Characterization of ‘active’ surfaces during modification at atomic-scale levels is becoming more important as advances in processing modalities are limited by an understanding of the behavior of these surfaces under realistic environmental conditions. Self-organization from exposure to non-equilibrium and thermalized plasmas enable dramatic control of surface morphology, topography, composition, chemistry and structure yielding the ability to tune material properties with an unprecedented level of control. Deciphering self-organization mechanisms of nanoscale morphology (e.g. nanodots, ripples) and composition on a variety of materials including: compound semiconductors, semiconductors, ceramics, polymers and polycrystalline metals via low-energy ion-beam assisted plasma irradiation are critical to manipulate functionality in nanostructured systems. By operating at ultra-low energies near the damage threshold, irradiation-driven defect engineering can be optimized and surface-driven mechanisms controlled. Tunability of optical, electronic, magnetic and bioactive properties is realized by reaching metastable phases controlled by atomic-scale irradiation-driven mechanisms elucidated by novel in situ diagnosis coupled to atomistic-level computational tools. Emphasis will be made on tailored surface modification from plasma-enhanced environments on particle-surface interactions and their subsequent modification of hard and soft matter interfaces. In this review, we examine current trends towards in situ and in operando surface and sub-surface characterization to unravel atomic-scale mechanisms at the plasma-material interface. This work will emphasize on recent advances in the field of plasma and ion

  13. New Results on Plasma Activated Bonding of Imprinted Polymer Features for Bio MEMS Applications

    NASA Astrophysics Data System (ADS)

    Kettner, P.; Pelzer, R. L.; Glinsner, T.; Farrens, S.; Lee, D.

    2006-04-01

    Nanoimprint Lithography is a well-acknowledged low cost, high resolution, large area 3D patterning process for polymers. It includes the most promising methods: high pressure hot embossing (HE) and UV-Nanoimprint Lithography (UV-NIL). Curing of the imprinted structures is either done by cooling down below the glass transition temperature of the thermoplastic polymer in case of HE or by subsequent UV-light exposure and cross-linking in case of UV-NIL. Both techniques allow rapid prototyping for high volume production of fully patterned substrates for a wide range of materials. The advantages of using polymer substrates over common Micro-Electro-Mechanical Systems (MEMS) processing materials like glass, silicon or quartz are: bio-compatible surfaces, easy manufacturability, low cost for high volume production, suitable for use in micro- and nano-fabrication, low conductivity, wide range of optical properties just to name a few. We will present experimental results on HE processes with PMMA as well as UV-NIL imprints in selected UV-curable resists. In the second part of the work we will describe the bonding techniques for packaging of the micro or nano structures. Packaging of the imprinted features is a key technology for a wide variety of field of applications: µ-TAS, biochemistry, micro-mixers, micro-reactors, electrophoresis cells, life science, micro-optical and nano-optical applications (switches) nanofluidics, data storage, etc. for features down to sub-100 nm range. Most bonding techniques for polymer use adhesives as intermediate layers. We will demonstrate a promising technique for dense and very strong bonds using plasma activation of polymers and glass. This bonding technology allows for bonding at low temperatures well below the glass transition temperature of the polymers, which will ensure that the structures are not deformed.

  14. Dissecting Ubiquitin Folding Using the Self-Organized Polymer Model.

    PubMed

    Reddy, Govardhan; Thirumalai, D

    2015-08-27

    Folding of Ubiquitin (Ub), a functionally important protein found in eukaryotic organisms, is investigated at low and neutral pH at different temperatures using simulations of the coarse-grained self-organized-polymer model with side chains (SOP-SC). The melting temperatures (Tm's), identified with the peaks in the heat capacity curves, decrease as pH decreases, in qualitative agreement with experiments. The calculated radius of gyration, showing dramatic variations with pH, is in excellent agreement with scattering experiments. At Tm, Ub folds in a two-state manner at low and neutral pH. Clustering analysis of the conformations sampled in equilibrium folding trajectories at Tm, with multiple transitions between the folded and unfolded states, shows a network of metastable states connecting the native and unfolded states. At low and neutral pH, Ub folds with high probability through a preferred set of conformations resulting in a pH-dependent dominant folding pathway. Folding kinetics reveal that Ub assembly at low pH occurs by multiple pathways involving a combination of nucleation-collapse and diffusion collision mechanism. The mechanism by which Ub folds is dictated by the stability of the key secondary structural elements responsible for establishing long-range contacts and collapse of Ub. Nucleation collapse mechanism holds if the stability of these elements are marginal, as would be the case at elevated temperatures. If the lifetimes associated with these structured microdomains are on the order of hundreds of microseconds, then Ub folding follows the diffusion-collision mechanism with intermediates, many of which coincide with those found in equilibrium. Folding at neutral pH is a sequential process with a populated intermediate resembling that sampled at equilibrium. The transition state structures, obtained using a Pfold analysis, are homogeneous and globular with most of the secondary and tertiary structures being native-like. Many of our findings for

  15. Controlling the Surface Organization of Conjugated Donor-Acceptor Polymers by their Aggregation in Solution.

    PubMed

    Li, Mengmeng; An, Cunbin; Marszalek, Tomasz; Baumgarten, Martin; Yan, He; Müllen, Klaus; Pisula, Wojciech

    2016-11-01

    The aggregation of conjugated polymers is found to have a significant influence on the surface organization of deposited films. Difluorobenzothiadiazole-based polymers show a strong pre-aggregation in solution, but the addition of 1,2,4-trichlorobenzene efficiently reduces such aggregates, leading to the transition of the surface organization from edge- to face-on orientation in deposited films. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. 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.

  17. A study of the initial film growth of PEG-like plasma polymer films via XPS and NEXAFS

    NASA Astrophysics Data System (ADS)

    Li, Yali; Muir, Benjamin W.; Easton, Christopher D.; Thomsen, Lars; Nisbet, David R.; Forsythe, John S.

    2014-01-01

    The chemistry of substrate-film interface (underside) of di(ethylene glycol) dimethyl ether plasma polymer (DGpp) films has been studied directly and compared to the top layer of the film (topside). By depositing the plasma polymer films onto indium tin oxide (ITO) glass, the films were easily delaminated from the substrate. The top- and underside of the films were examined by X-ray photoelectron spectroscopy (XPS) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. It was found that a rapid increase in pressure during plasma polymerization results in steep chemical gradients in the films, while small pressure changes do not lead to chemical gradient formation. These observations validate the findings of previous neutron reflectometry modeling studies of this class of plasma polymer thin film. In addition, subtle variations in plasma polymer film chemistry were observed between different substrates they were deposited onto. This approach will allow additional studies on the mechanisms of early plasma polymer thin film formation with various monomers.

  18. 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.

  19. 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. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. 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.

  1. Probing film-depth-related light harvesting in polymer solar cells via plasma etching

    NASA Astrophysics Data System (ADS)

    Gao, Shuang; Bu, Laju; Zheng, Zhong; Wang, Xudong; Wang, Weichen; Zhou, Ling; Hou, Jianhui; Lu, Guanghao

    2017-04-01

    Light harvesting is the first step of photovoltaic process in polymer solar cells. However, such donor: acceptor bulk junction layers are usually featured with vertical phase segregation as well as film-depth-dependent molecular aggregation, chain orientation and crystallinity, leading to a significant variation of photon absorption and exciton generation at different film-depths. We propose an experimentally and numerically accessible method to investigate the depth-dependent light harvesting behaviors in the active layer in polymer solar cells. A low-pressure oxygen plasma is utilized to etch the active layer gradually which is monitored by a light absorption spectrometer. Including the obtained sublayer absorption spectra into transfer matrix optical model yields depth-dependent optical properties and exciton generation profiles, which contribute to quantum efficiency and short-circuit current. This approach is helpful to optimize vertical material variation and provide insights into photovoltaic process.

  2. 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.

  3. Cell immobilization on polymer by air atmospheric pressure plasma jet treatment

    NASA Astrophysics Data System (ADS)

    Lee, Jung-Hwan; Kwon, Jae-Sung; Om, Ji-yeon; Kim, Yong-Hee; Choi, Eun-Ha; Kim, Kwang-Mahn; Kim, Kyoung-Nam

    2014-08-01

    The study of cell immobilization on delicate polymer by an air atmospheric pressure plasma jet (AAPPJ) is required for its medical application. The aim of this study was to evaluate whether AAPPJ treatment induce cell immobilization effect on delicate polymers without significant change of surface roughness by AAPPJ treatment. After surface roughness, dynamic contact angle, and chemical characteristics were investigated, the immobilization effect was evaluated with the mouse fibroblast L929 cell line. Surface roughness change was not observed (P > 0.05) in either delicate dental wax or polystyrene plate (PSP) as advancing and receding contact angles significantly decreased (P < 0.05), thanks to decreased hydrocarbon and formation of oxygen-related functional groups in treated PSP. Adherent L929 cells with elongated morphology were found in treated PSP along with the formation of immobilization markers vinculin and actin cytoskeleton. Increased PTK2 gene expression upregulated these markers on treated PSP.

  4. Effects of substrate bias power on the surface of ITO electrodes during O2/CF4 plasma treatment and the resulting performance of organic light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Han, D. M.; Lee, J. H.; Jeong, K. H.; Lee, J. G.

    2010-08-01

    During surface treatment using O2/CF4 plasma chemistry, the bias power applied to the indium-tin-oxide(ITO) substrate significantly degrades the electrical and optical performance of the organic light emitting diode (OLED) formed on the ITO electrode as a result of the formation of CFx polymer, In-Sn-F compounds, and structural defects. Application of bias power to the substrate effectively increases the sheath potential over the substrate and thus the flux of CFx + ion created in the O2/CF4 plasma, which leads to the production of CFx polymers as well as structural defects.

  5. 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

  6. Directly patternable, highly conducting polymers for broad applications in organic electronics.

    PubMed

    Yoo, Joung Eun; Lee, Kwang Seok; Garcia, Andres; Tarver, Jacob; Gomez, Enrique D; Baldwin, Kimberly; Sun, Yangming; Meng, Hong; Nguyen, Thuc-Quyen; Loo, Yueh-Lin

    2010-03-30

    Postdeposition solvent annealing of water-dispersible conducting polymers induces dramatic structural rearrangement and improves electrical conductivities by more than two orders of magnitude. We attain electrical conductivities in excess of 50 S/cm when polyaniline films are exposed to dichloroacetic acid. Subjecting commercially available poly(ethylene dioxythiophene) to the same treatment yields a conductivity as high as 250 S/cm. This process has enabled the wide incorporation of conducting polymers in organic electronics; conducting polymers that are not typically processable can now be deposited from solution and their conductivities subsequently enhanced to practical levels via a simple and straightforward solvent annealing process. The treated conducting polymers are thus promising alternatives for metals as source and drain electrodes in organic thin-film transistors as well as for transparent metal oxide conductors as anodes in organic solar cells and light-emitting diodes.

  7. Water-Resistant and Transparent Plastic Films from Functionalizable Organic Polymers: Coordination Polymers as Templates for Solid-State [2+2]-Photopolymerization.

    PubMed

    Garai, Mousumi; Biradha, Kumar

    2017-01-05

    An organic polymer containing cyclobutanes and amides as backbones and pyridyl groups as sidearms was synthesized by single-crystal-to-single-crystal (SCSC) [2+2]-photopolymerization in the coordination polymers (CPs) of diene. The diene molecule was photo-inactive in its crystals and formed a triply intertwined 1D-helical CP with Cd(NO3 )2 and Cu(NO3 )2 salts. The 1D-CP was transformed into a coordination polymer of organic polymers containing threefold interpenetrated 3D-networks of CdSO4 topology through a [2+2]-reaction in SCSC manner upon irradiation. The organic polymer was separated from its CPs and found to have an unusually high degree of polymerization for this type of reaction. Furthermore, the organic polymer was amenable for N-alkylation reactions such as methylation, propylation, and decylation. The formate salts of the organic polymer and the methylated polymer were shown to form plastic films with a combination of properties such as high transparency, tensile strengths, gas permeability, thermal stability, water-resistance, and resistance to other organic solvents. The methylated polymer was also able to capture chromate ions and anionic dyes from aqueous solutions.

  8. 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.

  9. New methodologies for construction of hyperbranched organic and organometallic polymers

    NASA Astrophysics Data System (ADS)

    Xu, Kaitian

    2000-10-01

    A series of completely soluble hyperbranched polymers were synthesized by polycyclotrimerization of diynes for the first time. TaCl5-Ph 4Sn was found to be the effective catalyst and toluene to be the efficient solvent. A possible polycyclotrimerization mechanism via tantalacyclopentadiene intermediates is proposed. The polymerization processes including initiation, propagation and termination are analyzed. The unique backbiting reaction was found to be a plausible way to terminate the propagation chain. Conformations of the diynes greatly affect the occurrence of backbiting reaction and affect the solubility of resultant polymers to certain extent. Diynes with short spacers such as 1,5-hexadiyne (21 ); 1,6-heptadiyne (22); 1,7-octadiyne (23); and 1,8-nonadiyne (17); possess a conformation in which the two triple bonds locate closely. Such a conformation makes the backbiting termination to occur easily. Thus, soluble polymers are readily formed from these diynes. For the diynes of long spacers, a conformation with two far-separating triple bonds dramatically reduces the chance of backbiting reaction. Consequently, only partially soluble or insoluble polymers could be prepared. In the polycyclotrimerization of internal diynes, hexasubstituted benzene rings were formed. The steric effect of the terminal substituents plays an important role in the polymerization reaction. Internal diynes with bulky substituents such as 1,9-bis(trimethylsilyl)-1,8-nonadiyne (74), 1,6-bis(dimethylphenylsilyl)-1,5-hexadiyne (75), 1,8-bis(dimethylphenylsilyl)-1,7-octadiyne (76) gave little amount of polymers. Internal diynes with less bulky substituents and short spacers [e.g. 3,9-dodecadiyne (78) and 2,9-undecadiyne (79)] offered soluble polymers. In the study on hyperbranched organometallic polymers, a new methodology for the preparation of hyperbranched polysilynes was developed. Ceramization of the hyperbranched polymers produced mesoporous magnetoceramic materials. The compositions

  10. Design of pervaporation membrane for organic-liquid separation based on solubility control by plasma-graft filling polymerization technique

    SciTech Connect

    Yamaguchi, Takeo; Nakao, Shinichi; Kimura, Shoji )

    1993-05-01

    Pervaporation performance through the membranes showed the same tendency as solubility results. The authors have prepared the filling-polymerized membrane for pervaporation of organic-liquid mixtures by the plasma-graft polymerization technique. The membrane is composed of two different polymers: a porous substrate which can suppress membrane swelling and a grafted polymer which forms in the pores of the substrate and exhibits selectivity due to its solubility. The objectives of the present study are to design a suitable membrane for an organic-mixture system by the control of the filling-polymer solubility. Specifically, a porous high-density polyethylene membrane and poly(methylacrylate/acrylamide) copolymer were employed as the porous substrate and grafted polymer, respectively, and grafted copolymer solubility was predicted by Hansen solubility parameters (HSP). The grafted polymer composition and its solubility behavior could be controlled by varying the monomer composition, and the solubility change was in accordance with the prediction by HSP. Pervaporation performance through the membranes showed the same tendency as solubility results. The authors concluded that an optimum pervaporation membrane can be designed on the basis of solubility control through use of these techniques for polymerization and prediction.

  11. 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.

  12. Properties of Plasma Enhanced Chemical Vapor Deposition Barrier Coatings and Encapsulated Polymer Solar Cells

    NASA Astrophysics Data System (ADS)

    Qi, Lei; Zhang, Chunmei; Chen, Qiang

    2014-01-01

    In this paper, we report silicon oxide coatings deposited by plasma enhanced chemical vapor deposition technology (PECVD) on 125 μm polyethyleneterephthalate (PET) surfaces for the purpose of the shelf lifetime extension of sealed polymer solar cells. After optimization of the processing parameters, we achieved a water vapor transmission rate (WVTR) of ca. 10-3 g/m2/day with the oxygen transmission rate (OTR) less than 0.05 cc/m2/day, and succeeded in extending the shelf lifetime to about 400 h in encapsulated solar cells. And then the chemical structure of coatings related to the properties of encapsulated cell was investigated in detail.

  13. 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

  14. Recent applications of polymer supported organometallic catalysts in organic synthesis.

    PubMed

    Kann, Nina

    2010-09-07

    Recent developments concerning the application of polymer supported organometallic reagents in solid phase synthesis are reviewed, with a special focus on methodology for carbon-carbon formation. Examples of reactions that are covered include the classical Suzuki, Sonogashira and Heck coupings, but also aryl amination, epoxide opening, rearrangements, metathesis and cyclopropanation. Applications in the field of asymmetric synthesis are also discussed.

  15. 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.

  16. Role of Cellulose Nanocrystals on the Microstructure of Maleic Anhydride Plasma Polymer Thin Films.

    PubMed

    Brioude, Michel M; Roucoules, Vincent; Haidara, Hamidou; Vonna, Laurent; Laborie, Marie-Pierre

    2015-07-01

    Recently, it was shown that the microstructure of a maleic anhydride plasma polymer (MAPP) could be tailored ab initio by adjusting the plasma process parameters. In this work, we aim to investigate the ability of cellulose nanocrystals (CNCs) to induce topographical structuration. Thus, a new approach was designed based on the deposition of MAPP on CNCs model surfaces. The nanocellulosic surfaces were produced by spin-coating the CNC suspension on a silicon wafer substrate and on a hydrophobic silicon wafer substrate patterned with circular hydrophilic microsized domains (diameter of 86.9 ± 4.9 μm), resulting in different degrees of CNC aggregation. By depositing the MAPP over these surfaces, it was possible to observe that the surface fraction of nanostructures increased from 20% to 35%. This observation suggests that CNCs can act as nucleation points resulting in more structures, although a critical density of the CNCs is required.

  17. Plasma surface modification of cyclo-olefin polymers and its application to lateral flow bioassays.

    PubMed

    Dudek, Magdalena M; Gandhiraman, R P; Volcke, C; Cafolla, Attilio A; Daniels, Stephen; Killard, Anthony J

    2009-09-15

    The modification of cyclo-olefin polymer Zeonor by plasma-enhanced chemical vapor deposition to form a silica-like surface and evaluation of its application for lateral flow bioassays applications are discussed in this study. The SiOx layer was extensively characterized using contact angle measurements, atomic force microscopy, and Fourier transform infrared spectroscopy in attenuated total internal reflectance mode where the presence of a uniform SiOx film was clearly identified. The SiOx modification resulted in a surface with enhanced wettability and excellent fluidic properties when combined with a hot-embossed micropillar capillary fill-based substrate. The SiOx surface also had the ability to accelerate the clotting of human plasma, which may have application in certain types of blood coagulation assays.

  18. 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.

  19. 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.

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

    PubMed

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

    2014-04-21

    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. 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.

  2. 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.

  3. Novel non-conjugated main-chain hole-transporting polymers for organic electronics application.

    PubMed

    Schelter, Jürgen; Mielke, Georg Felix; Köhnen, Anne; Wies, Jenna; Köber, Sebastian; Nuyken, Oskar; Meerholz, Klaus

    2010-09-01

    A new class of hole-transporting polymers for use in organic electronic devices such as organic light-emitting diodes (OLEDs) or photorefractive holographic storage devices has been synthesized. The polymers contain tetraarylbenzidines or tetraarylphenylenediamines as charge-transporting units in the polymer backbone and are connected by non-conjugating fluorene bridges. For use in OLEDs the novel polymers were functionalized with oxetane groups that can be cross-linked via a cationic ring opening polymerization to yield insoluble networks. Such insoluble films are necessary for the fabrication of multilayer devices by wet deposition techniques. The novel materials feature improved film-formation properties as demonstrated in green-emitting double-layer OLEDs.

  4. 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.

  5. Aqueous polymer two-phase systems: effective tools for plasma membrane proteomics.

    PubMed

    Schindler, Jens; Nothwang, Hans Gerd

    2006-10-01

    Plasma membranes (PMs) are of particular importance for all living cells. They form a selectively permeable barrier to the environment. Many essential tasks of PMs are carried out by their proteinaceous components, including molecular transport, cell-cell interactions, and signal transduction. Due to the key role of these proteins for cellular function, they take center-stage in basic and applied research. A major problem towards in-depth identification and characterization of PM proteins by modern proteomic approaches is their low abundance and immense heterogeneity in different cells. Highly selective and efficient purification protocols are hence essential to any PM proteome analysis. An effective tool for preparative isolation of PMs is partitioning in aqueous polymer two-phase systems. In two-phase systems, membranes are separated according to differences in surface properties rather than size and density. Despite their rare application to the fractionation of animal tissues and cells, they represent an attractive alternative to conventional fractionation protocols. Here, we review the principles of partitioning using aqueous polymer two-phase systems and compare aqueous polymer two-phase systems with other methods currently used for the isolation of PMs.

  6. Electroless plating of honeycomb and pincushion polymer films prepared by self-organization.

    PubMed

    Yabu, Hiroshi; Hirai, Yuji; Shimomura, Masatsugu

    2006-11-07

    This report describes the fabrication and electroless plating of regular porous and pincushion-like polymer structures prepared by self-organization. Honeycomb-patterned films were prepared by simple casting of polymer solution under applied humid air and pincushion structures by peeling off the top layer of the former films. Silver-deposited honeycomb-patterned films and pincushion films were obtained by simple electroless plating of the respective original structures. XPS revealed Ag deposition on the honeycomb-patterned film. After thermal decomposition or solvent elution of the template polymer, unique metal mesoscopic structures were obtained.

  7. Dynamic nuclear polarization NMR spectroscopy allows high-throughput characterization of microporous organic polymers.

    PubMed

    Blanc, Frédéric; Chong, Samantha Y; McDonald, Tom O; Adams, Dave J; Pawsey, Shane; Caporini, Marc A; Cooper, Andrew I

    2013-10-16

    Dynamic nuclear polarization (DNP) solid-state NMR was used to obtain natural abundance (13)C and (15)N CP MAS NMR spectra of microporous organic polymers with excellent signal-to-noise ratio, allowing for unprecedented details in the molecular structure to be determined for these complex polymer networks. Sensitivity enhancements larger than 10 were obtained with bis-nitroxide radical at 14.1 T and low temperature (∼105 K). This DNP MAS NMR approach allows efficient, high-throughput characterization of libraries of porous polymers prepared by combinatorial chemistry methods.

  8. Polymers based on stable phenoxyl radicals for the use in organic radical batteries.

    PubMed

    Jähnert, Thomas; Häupler, Bernhard; Janoschka, Tobias; Hager, Martin D; Schubert, Ulrich S

    2014-05-01

    Polymers with pendant phenoxyl radicals are synthesized and the electrochemical properties are investigated in detail. The monomers are polymerized using ring-opening metathesis polymerization (ROMP) or free-radical polymerization methods. The monomers and polymers, respectively, are oxidized to the radical either before or after the polymerization. These phenoxyl radicals containing polymers reveal a reversible redox behavior at a potential of -0.6 V (vs Ag/AgCl). Such materials can be used as anode-active material in organic radical batteries (ORBs).

  9. Investigations on laser ablation microwave induced plasma atomic emission spectrometry using polymer samples

    NASA Astrophysics Data System (ADS)

    Leis, F.; Bauer, H. E.; Prodan, L.; Niemax, K.

    2001-01-01

    The potential of laser ablation-microwave induced plasma-atomic emission spectrometry (LA-MIP-AES) for the analysis of plastic materials has been investigated. A Nd/YAG laser, operated in its fundamental mode at 1064 nm, was used to ablate small amounts of various plastics. The sample atoms were transported and excited in a closely neighbored continuously running microwave induced plasma (MIP) operated in argon or helium at reduced pressure. A 0.5-m échelle spectrometer, equipped with an intensified charge coupled device (ICCD) as a detector was used for recording the spectra. The amount of ablated material was found to be strongly dependent on the matrix (10-190 ng/shot). Signals for some metals often used as additives in polymers (Al, Ca, Cu, Sb, Ti) and for the elements F, Cl, Br, J, and P in various polymers were recorded in the spectral range 250-840 nm. The estimated detection limits were found to be in the range 0.001-0.08% for metals and 0.05-0.7% for non-metals. Spectral lines of fluorine and iodine could only be measured in the helium MIP. For high concentrations of chlorine and carbon in the samples (polyvinylchloride), a memory effect was observed.

  10. Development of silver nanoparticle loaded antibacterial polymer mesh using plasma polymerization process.

    PubMed

    Kumar, Virendra; Jolivalt, Claude; Pulpytel, Jerome; Jafari, Reza; Arefi-Khonsari, Farzaneh

    2013-04-01

    Plasma polymerized polyacrylic acid (PPAA) was deposited on a polymer substrate, namely polyethylene terephthalate (PET) mesh, for entrapment of silver nanoparticle (Ag-NP) in order to achieve antibacterial property to the material. Carboxylic groups of PPAA act as anchor as well as capping and stabilizing agents for Ag-NPs synthesized by chemical reduction method using NaBH(4) as a reducing agent. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy (XPS), and water contact angle analysis were used to characterize the PPAA coatings. The Ag-NPs loaded polymer samples were characterized by UV-visible spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray, and XPS techniques. XPS analysis showed ~1.0 at.% loading of Ag-NPs on to the PPAA-PET-mesh, which was composed of 79% zero-valent (Ag°) and 21% oxidized nano-Ag (Ag(+) ). The plasma processed PET meshes samples were tested for antibacterial activity against two bacterial strains, namely Staphylococcus aureus (Gram positive) and Escherichia coli (Gram negative). Qualitative and quantitative tests showed that silver containing PPAA-PET meshes exhibit excellent antibacterial property against the tested bacteria with percent reduction of bacterial concentration >99%, compared to the untreated PET mesh.

  11. Antibacterial burst-release from minimal Ag-containing plasma polymer coatings

    PubMed Central

    Lischer, Stefanie; Körner, Enrico; Balazs, Dawn J.; Shen, Dakang; Wick, Peter; Grieder, Kathrin; Haas, Dieter; Heuberger, Manfred; Hegemann, Dirk

    2011-01-01

    Biomaterials releasing silver (Ag) are of interest because of their ability to inhibit pathogenic bacteria including antibiotic-resistant strains. In order to investigate the potential of nanometre-thick Ag polymer (Ag/amino-hydrocarbon) nanocomposite plasma coatings, we studied a comprehensive range of factors such as the plasma deposition process and Ag cation release as well as the antibacterial and cytocompatible properties. The nanocomposite coatings released most bound Ag within the first day of immersion in water yielding an antibacterial burst. The release kinetics correlated with the inhibitory effects on the pathogens Pseudomonas aeruginosa or Staphylococcus aureus and on animal cells that were in contact with these coatings. We identified a unique range of Ag content that provided an effective antibacterial peak release, followed by cytocompatible conditions soon thereafter. The control of the in situ growth conditions for Ag nanoparticles in the polymer matrix offers the possibility to produce customized coatings that initially release sufficient quantities of Ag ions to produce a strong adjacent antibacterial effect, and at the same time exhibit a rapidly decaying Ag content to provide surface cytocompatibility within hours/days. This approach seems to be favourable with respect to implant surfaces and possible Ag-resistance/tolerance built-up. PMID:21247951

  12. 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

  13. Organic polymer chemistry in the context of novel processes

    DOE PAGES

    DeSimone, Joseph M.; Mecham, Sue J.; Farrell, Crista L.

    2016-09-13

    This paper 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 havemore » a tangible impact in the private sector through the translation of discoveries into the marketplace.« less

  14. Inorganic-Organic Polymers and Their Role in Materials Science

    DTIC Science & Technology

    1994-05-18

    developments. Poly(dimethylsiloxane) is widely used in biomedicine as an inert elastomer and as a matrix for the diffusion release of birth control...has been acheved by the preparation of composites that involve MEEP (21) and silicon, titanium , zArconium, or aluminum oxide crosslinked gels.[7Z7 3...flj 1140. [311 R. D. Miller, L. Rabolt, R. Sontyakman, W. Fleming, G. N. Fickes , B. L Farmre, H. Kunmany in Inorganic and Orgaomenac Polyme (Eds. M

  15. Formation and Properties of Polymers Used in Organic Matrix Composites.

    DTIC Science & Technology

    1983-09-01

    fX) f 111 Analysis of an epoxy system showed that diffusion influenced the reaction rate only at vitrification (4). The general kinetic equation...vitrification and the time to vitrify, like gelation, decrease with increasing functionality (5). m) For epoxies the reactions become diffusion controlled in...Applied Polymer Science, Vol. 27, 1327-1334 (1982). S. N. T. Aronhime and 3. K. Gillham, "The Transformation of Liquid to Amorphous Solid: Effect of

  16. Recent Advances in Polymer Organic Light-Emitting Diodes (PLED) Using Non-conjugated Polymers as the Emitting Layer and Contrasting Them with Conjugated Counterparts

    NASA Astrophysics Data System (ADS)

    Wong, Michael Y.

    2017-07-01

    Polymer organic light-emitting diodes (PLED) are one of the most studied subjects in flexible electronics thanks to their economical wet fabrication procedure for enhanced price advantage of the product device. In order to optimize PLED efficiency, correlating the polymer structure with the device performance is essential. An important question for the researchers in this field is whether the polymer backbone is conjugated or not as it affects the device performance. In this review, recent advances in non-conjugated polymers employed as the emitting layer in PLED devices are first discussed, followed by their contrast with the conjugated counterparts in terms of polymer synthesis, sample quality, physical properties and device performances. Such comparison between conjugated and non-conjugated polymers for PLED applications is rarely attempted, and; hence, this review shall provide a useful insight of emitting polymers employed in PLEDs.

  17. Nuclear relaxation measurements in organic semiconducting polymers for application to organic spintronics

    NASA Astrophysics Data System (ADS)

    Thenell, E. F.; Limes, M. E.; Sorte, E. G.; Vardeny, Z. V.; Saam, B.

    2015-01-01

    NMR measurements of spin-lattice relaxation of hydrogen nuclei in two prototype organic semiconducting solids, MEH-PPV and DOO-PPV, were carried out for temperatures between 4.2 K and room temperature, and for applied magnetic fields between 1.25 and 4.7 T. These π -conjugated polymers are of interest for use as the active semiconducting layer in spintronic devices. They typically exhibit weak spin-orbit coupling, and the interaction with inhomogeneous hyperfine fields generated by the nuclear spins plays a significant, if not dominant, role in the spin coherence and spin relaxation of electronic charge carriers. Our studies were conducted on unbiased bulk material with no photo-illumination. The characteristic 1H longitudinal relaxation times in these materials ranges from hundreds of milliseconds to >1000 s, and are predominantly nonmonoexponential. We present the data both in terms of a recovery time, T1 /2, corresponding to 50% recovery of thermal magnetization from saturation and in terms of a "T1 spectrum" produced via a numerical Laplace transform of the time-domain data. The evidence best supports relaxation to paramagnetic centers (radicals) mediated by nuclear spin diffusion as the primary mechanism: the observed relaxation is predominantly nonmonoexponential, and a characteristic T1 minimum as a function of temperature is apparent for both materials somewhere between 77 K and room temperature. The paramagnetic centers may be somewhat-delocalized charge-carrier pairs (i.e., polarons) along the polymer backbone, although the concentration in an unbiased sample (no carrier injection) should be very low. Alternatively, the centers may be localized defects, vacancies, or impurities. Our results may also be used to judge the feasibility of Overhauser-type dynamic nuclear polarization from polarized charge carriers or optically pumped exciton states.

  18. 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.

  19. Transformation of polymer composite nanofibers to diamond fibers and films by microwave plasma-enhanced CVD process

    NASA Astrophysics Data System (ADS)

    Potocký, Š.; Ižák, T.; Rezek, B.; Tesárek, P.; Kromka, A.

    2014-09-01

    In this work, polyvinyl alcohol (PVA) fibers were used as a polymer matrix containing ultra-dispersed diamond (UDD) nanoparticles. Growth of diamond fiber-like structures and films by microwave plasma-enhanced chemical vapor deposition was studied as a function of UDD concentration in the PVA matrix. The influence of surface tension (fibers radii) for nucleation/seeding is discussed. Using a high UDD concentration in the polymer matrix lead to the formation of fiber-like structures. The composite PVA polymer nanofibers with the highest concentration of UDD nanoparticles resulted in the growth of nearly continuous diamond film at low thickness of 250 nm.

  20. 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

  1. 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.

  2. Novel Imprinted Polymer for the Preconcentration of Cadmium with Determination by Inductively Coupled Plasma Mass Spectrometry.

    PubMed

    Yilmaz, Vedat; Yilmaz, Hayriye; Arslan, Zikri; Leszczynski, Jerzy

    2017-01-01

    A novel Cd(II)-imprinted polymer was prepared with chemical immobilization approach by using N-methacryloyl-L-histidine as a vinylated chelating agent for on-line solid phase extraction of Cd(II) for determination by inductively coupled plasma mass spectrometry. Cd(II)-monomer complex was synthesized and copolymerized via bulk polymerization method in the presence of ethyleneglycoldimethacrylate cross-linker. The resulting polymer was leached with 1.0 mol L(-1) HNO3 to generate the cavities in the polymer for Cd(II) ions. The experimental conditions, including load pH, solution flow rate, and eluent concentration for effective sorption of Cd(II) were optimized using a minicolumn of the imprinted polymer. A volume of 5.0 mL sample 5 μg L(-1) Cd(II) solution at pH 6.5 was loaded onto the column at 2.0 mL min(-1) by using a sequential injection system (FIALab 3200) followed by elution with 1.0 mL of 0.75 mol L(-1) HNO3. The relative selectivity coefficients of the imprinted polymer for Cd(II) were 38.5, 3.5, 3.0, 2.5 and 6.0 in the presence of Cu(II), Ni(II), Zn(II), Co(II) and Pb(II), respectively. Computational calculations revealed that the selectivity of the imprinted polymer was mediated by the stability of Cd(II)-N-methacryloyl-L-histidine complex which was far more stable than those of commonly used monomers, such as 4-vinyl pyridine, methacrylic acid and vinylimidazole. The detection limit (3s) and relative standard deviation (%) were found to be 0.004 μg L(-1) and 3.2%, respectively. The method was validated by analysis of seawater certified reference material (CASS-4) and successfully applied to the determination of Cd(II) in coastal seawater and estuarine water samples.

  3. Organic electronics with polymer dielectrics on plastic substrates fabricated via transfer printing

    NASA Astrophysics Data System (ADS)

    Hines, Daniel R.

    Printing methods are fast becoming important processing techniques for the fabrication of flexible electronics. Some goals for flexible electronics are to produce cheap, lightweight, disposable radio frequency identification (RFID) tags, very large flexible displays that can be produced in a roll-to-roll process and wearable electronics for both the clothing and medical industries. Such applications will require fabrication processes for the assembly of dissimilar materials onto a common substrate in ways that are compatible with organic and polymeric materials as well as traditional solid-state electronic materials. A transfer printing method has been developed with these goals and application in mind. This printing method relies primarily on differential adhesion where no chemical processing is performed on the device substrate. It is compatible with a wide variety of materials with each component printed in exactly the same way, thus avoiding any mixed processing steps on the device substrate. The adhesion requirements of one material printed onto a second are studied by measuring the surface energy of both materials and by surface treatments such as plasma exposure or the application of self-assembled monolayers (SAM). Transfer printing has been developed within the context of fabricating organic electronics onto plastic substrates because these materials introduce unique opportunities associated with processing conditions not typically required for traditional semiconducting materials. Compared to silicon, organic semiconductors are soft materials that require low temperature processing and are extremely sensitive to chemical processing and environmental contamination. The transfer printing process has been developed for the important and commonly used organic semiconducting materials, pentacene (Pn) and poly(3-hexylthiophene) (P3HT). A three-step printing process has been developed by which these materials are printed onto an electrode subassembly consisting

  4. Novel benzodithiophene-based polymer acceptors for efficient organic solar cells.

    PubMed

    Wang, Yan-Ling; Li, Quan-Song; Li, Ze-Sheng

    2017-08-30

    All polymer organic solar cells afford unique potentials due to the tunable chemical and electronic properties of both polymer donors and polymer acceptors. Compared with the rapid development of polymer donors, the development of polymer acceptors lags far behind. To seek high-performance polymer acceptors used in organic solar cells, based on the experimentally reported D-A polymer acceptor (NDI2OD-T2)n (P1), a series of novel acceptors, designated as (BDTNDI2OD-T2)n(P2), (BDTNDTI)n(P3), (BDTNDI2OD-Tz2)n(P4), and (BDTNDTzI)n(P5), were designed by introduction of a benzodithiophene (BDT) unit and the nitrogen atom in the bridged thiophene ring. The density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods were applied to study the effect of the BDT unit and the nitrogen atom on the geometrical, optical, electronic, and charge transport properties. The obtained results show that incorporation of the electron-donating BDT unit into P1 and the replacement of a carbon atom by the nitrogen atom in the bridged thiophene ring are effective strategies to lower the lowest unoccupied molecular orbital (LUMO) energy and exciton binding energy, and enhance light-absorbing capacity and electron mobility. Moreover, among the investigated molecules, P2 and P5 exhibit stronger and broader light absorption, higher light absorption efficiency and exciton separation ability as well as electron mobility; therefore they are recommended as promising polymer acceptors for future high-efficiency organic solar cells.

  5. 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.

  6. 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)

  7. 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)

  8. 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.

  9. Optical properties of self-organized gold nanorod-polymer hybrid films.

    PubMed

    Tritschler, Ulrich; Zlotnikov, Igor; Keckeis, Philipp; Schlaad, Helmut; Cölfen, Helmut

    2014-11-25

    High fractions of gold nanorods were locally aligned by means of a polymeric liquid crystalline phase. The gold nanorods constituting >80 wt % of the thin organic-inorganic composite films form a network with side-by-side and end-to-end combinations. Organization into these network structures was induced by shearing gold nanorod-LC polymer dispersions via spin-coating. The LC polymer is a polyoxazoline functionalized with pendent cholesteryl and carboxyl side groups enabling the polymer to bind to the CTAB stabilizer layer of the gold nanorods via electrostatic interactions, thus forming the glue between organic and inorganic components, and to form a chiral nematic lyotropic phase. The self-assembled locally oriented gold nanorod structuring enables control over collective optical properties due to plasmon resonance coupling, reminiscent of enhanced optical properties of natural biomaterials.

  10. 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.

  11. Plasmas as a Prototypical Complex System: Self-Organized Criticality as a Paradigm for Plasma Transport

    NASA Astrophysics Data System (ADS)

    Newman, David

    2001-04-01

    In nature there are many systems which exhibit some form of self-organization. Among these are forest fires, earthquakes, sandpiles, maybe sunspots and even life itself. Investigations into the similarity of the dynamics of such systems have been undertaken by using simple cellular automata models. These models have produced some important insight into the dynamics of such systems. Recently a Self-Organized Criticality (SOC) model for turbulent transport in magnetically confined plasmas has been proposed in order to explain some of the observed features of the transport dynamics in these plasmas. This model is based on the dynamics of a sandpile and has among others, the remarkable feature that a sheared wind across the sandpile (or a flow across the plasma) can fundamentally change the transport. The dynamics of the model show some remarkably similar characteristics to the observed data and suggest explanations for some puzzling aspects of the observations. Adding new, physically realistic, dynamical transport mechanisms such as classical diffusion to the SOC system have been found to lead to a new set of dynamical regimes with evidence of critical transitions between them. These regimes can then be explored in the plasma experiments. In addition to the intrinsic novelty of the basic physics involved, these observations can have interesting ramifications for the control of many real systems. Some of these features of the SOC systems, from forest fires to earthquakes, and the extension to the sandpile model for turbulent transport will be discussed.

  12. Novel Organic Polymer Films for Real-time Holographic Processing

    DTIC Science & Technology

    2007-11-02

    Because of the modelo In behavior of the arctangent function, the range is wrapped (ambiguous) beyond the so-called synthetic wavelength TB01JMF.DOC...photorefractive polymer with high optical gain and diffraction efficiency near 100%", Nature ’ill, pp . 497-500 (1994). 2 S. Ducharme, J.C. Scott, R.J. Tweig...W.E. Moerner, Phys. Rev. Lett., 66, pp . 1846-1849 (1991). 3 W.E. Moerner and S.M. Silence, "Polymeric Photorefractive Materials", Chem. Rev. 94, pp

  13. The Miscibility of PCBM in Low Band-Gap Conjugated Polymers in Organic Photovoltaics

    NASA Astrophysics Data System (ADS)

    Chen, Huipeng; You, Wei; Peet, Jeff; Azoulay, Jason; Bazan, Guillermo; Dadmun, Mark

    2012-02-01

    Understanding the morphology of the photoactive layer in organic photovoltaics (OPVs) is essential to optimizing conjugated polymer-based solar cells to meet the targeted efficiency of 10%. The miscibility and interdiffusion of components are among the key elements that impact the development of morphology and structure in OPV active layers. This study uses neutron reflectivity to correlate the structure of low band gap polymers to their miscibility with PCBM. Several low band gap polymers that exhibit power conversion efficiencies exceeding 7%, including PBnDT-DTffBT were examined. The intermixing of low band-gap polymer and PCBM bilayers was monitored by neutron reflectivity before and after thermal annealing, providing quantification of the miscibility and interdiffusion of PCBM within the low band gap polymer layer. These results indicate that the miscibility of PCBM ranges from 3% to 26% with the low band-gap polymers studied. The correlation between low band gap polymer structure and miscibility of PCBM will also be discussed.

  14. 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.

  15. Conformational Evolution of Elongated Polymer Solutions Tailors the Polarization of Light-Emission from Organic Nanofibers

    PubMed Central

    2014-01-01

    Polymer fibers are currently exploited in tremendously important technologies. Their innovative properties are mainly determined by the behavior of the polymer macromolecules under the elongation induced by external mechanical or electrostatic forces, characterizing the fiber drawing process. Although enhanced physical properties were observed in polymer fibers produced under strong stretching conditions, studies of the process-induced nanoscale organization of the polymer molecules are not available, and most of fiber properties are still obtained on an empirical basis. Here we reveal the orientational properties of semiflexible polymers in electrospun nanofibers, which allow the polarization properties of active fibers to be finely controlled. Modeling and simulations of the conformational evolution of the polymer chains during electrostatic elongation of semidilute solutions demonstrate that the molecules stretch almost fully within less than 1 mm from jet start, increasing polymer axial orientation at the jet center. The nanoscale mapping of the local dichroism of individual fibers by polarized near-field optical microscopy unveils for the first time the presence of an internal spatial variation of the molecular order, namely the presence of a core with axially aligned molecules and a sheath with almost radially oriented molecules. These results allow important and specific fiber properties to be manipulated and tailored, as here demonstrated for the polarization of emitted light. PMID:25067856

  16. 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.

  17. 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

  18. 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

  19. Multilayer Coextrusion of Polymer Composites to Develop Organic Capacitors

    DOE PAGES

    Mondy, L.; Mrozek, R.; Rao, 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 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

  20. 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.

  1. In vitro apatite formation on organic polymers modified with a silane coupling reagent.

    PubMed

    Shirosaki, Yuki; Kubo, Masaaki; Takashima, Seisuke; Tsuru, Kanji; Hayakawa, Satoshi; Osaka, Akiyoshi

    2005-09-22

    Gamma-methacryloxypropyltrimethoxysilane (gamma-MPS) was grafted to high-density polyethylene, polyamide and silicone rubber substrates by the emulsion polymerization procedure in order to provide these organic polymers with in vitro apatite-forming ability. The contact angles towards distilled water of the gamma-MPS-grafted specimens were lower than those of the original organic polymer specimens, indicating that the grafted substrates were more hydrophilic. The in vitro apatite formation in a simulated body fluid (Kokubo solution) was confirmed for several of the gamma-MPS-grafted specimens.

  2. Response delay caused by dielectric relaxation of polymer insulators for organic transistors and resolution method

    NASA Astrophysics Data System (ADS)

    Suemori, Kouji; Kamata, Toshihide

    2012-08-01

    We investigated the effect of dielectric relaxation in polymer gate insulators on the device characteristics of organic field effect transistors. Dielectric relaxation of polymer gate insulators caused an increase in drain current (ID) in a period starting immediately after the application of the gate voltage (VG) and lasting several milliseconds. This induced an apparent delay in the response of ID. Based on the observed results, we suggested an ideal gate insulator to achieve organic field effect transistors that have a fast response and high performance.

  3. In vitro apatite formation on organic polymers modified with a silane coupling reagent

    PubMed Central

    Shirosaki, Yuki; Kubo, Masaaki; Takashima, Seisuke; Tsuru, Kanji; Hayakawa, Satoshi; Osaka, Akiyoshi

    2005-01-01

    γ-Methacryloxypropyltrimethoxysilane (γ-MPS) was grafted to high-density polyethylene, polyamide and silicone rubber substrates by the emulsion polymerization procedure in order to provide these organic polymers with in vitro apatite-forming ability. The contact angles towards distilled water of the γ-MPS-grafted specimens were lower than those of the original organic polymer specimens, indicating that the grafted substrates were more hydrophilic. The in vitro apatite formation in a simulated body fluid (Kokubo solution) was confirmed for several of the γ-MPS-grafted specimens. PMID:16849191

  4. 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. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Assorted Phenoxyl-Radical Polymers and Their Application in Lithium-Organic Batteries.

    PubMed

    Jähnert, Thomas; Hager, Martin D; Schubert, Ulrich S

    2016-04-01

    The synthesis and electrochemical characterization of novel polymers bearing phenoxyl-radicals as redox-active side chains is described. The monomers are synthesized from the corresponding phenols and quinones, respectively. These compounds are subsequently poly-merized via ring-opening metathesis polymerization. The electrochemical properties of the phenoxyl-radical polymers are characterized using cyclic voltammetry and the most promising polymer is investigated as active material in a lithium coin-cell, creating the first phenoxyl-lithium battery. These phenoxyl-containing polymers represent interesting anode materials for organic radical and lithium batteries due to their suitable redox-potentials and possibility to create batteries with higher potentials as well as straightforward synthesis procedures. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Novel Strategy for Photopatterning Emissive Polymer Brushes for Organic Light Emitting Diode Applications

    PubMed Central

    2017-01-01

    A light-mediated methodology to grow patterned, emissive polymer brushes with micron feature resolution is reported and applied to organic light emitting diode (OLED) displays. Light is used for both initiator functionalization of indium tin oxide and subsequent atom transfer radical polymerization of methacrylate-based fluorescent and phosphorescent iridium monomers. The iridium centers play key roles in photocatalyzing and mediating polymer growth while also emitting light in the final OLED structure. The scope of the presented procedure enables the synthesis of a library of polymers with emissive colors spanning the visible spectrum where the dopant incorporation, position of brush growth, and brush thickness are readily controlled. The chain-ends of the polymer brushes remain intact, affording subsequent chain extension and formation of well-defined diblock architectures. This high level of structure and function control allows for the facile preparation of random ternary copolymers and red–green–blue arrays to yield white emission. PMID:28691078

  7. Surface Activation of Plane and Curved Automotive Polymer Surfaces by Using a Fittable Multi-Pin DBD Plasma Source

    NASA Astrophysics Data System (ADS)

    Jörn, Heine; Roland, Damm; Christoph, Gerhard; Stephan, Wieneke; Wolfgang, Viöl

    2014-06-01

    In this work, surface activation of automotive polymers using atmospheric pressure plasmas was investigated. The aim was to increase the polar fraction of the surface energy of both plane and convex polymer devices with a radius in the range of 30 mm. For this purpose, a fittable low temperature atmospheric pressure plasma source based on capacitively coupled multi-pin electrodes was set up and applied. Each single electrode generates a treatment spot of approximately 2 cm2 with a tunable power density of up to 1.4 W/cm2. The surface energy was evaluated by contact angle measurements. After treatment at a low energy density of 1.01 J/cm2, the polar fraction of the surface energy of the investigated polymers was increased by a factor of 3.3 to 132, depending on the polymer materials. It was shown that by applying the presented fittable plasma source, this effect is independent of the surface radius of the polymer sample.

  8. Gold nanoparticle-polymer nanocomposites synthesized by room temperature atmospheric pressure plasma and their potential for fuel cell electrocatalytic application

    NASA Astrophysics Data System (ADS)

    Zhang, Ri-Chao; Sun, Dan; Zhang, Ruirui; Lin, Wen-Feng; Macias-Montero, Manuel; Patel, Jenish; Askari, Sadegh; McDonald, Calum; Mariotti, Davide; Maguire, Paul

    2017-04-01

    Conductive polymers have been increasingly used as fuel cell catalyst support due to their electrical conductivity, large surface areas and stability. The incorporation of metal nanoparticles into a polymer matrix can effectively increase the specific surface area of these materials and hence improve the catalytic efficiency. In this work, a nanoparticle loaded conductive polymer nanocomposite was obtained by a one-step synthesis approach based on room temperature direct current plasma-liquid interaction. Gold nanoparticles were directly synthesized from HAuCl4 precursor in poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). The resulting AuNPs/PEDOT:PSS nanocomposites were subsequently characterized under a practical alkaline direct ethanol fuel cell operation condition for its potential application as an electrocatalyst. Results show that AuNPs sizes within the PEDOT:PSS matrix are dependent on the plasma treatment time and precursor concentration, which in turn affect the nanocomposites electrical conductivity and their catalytic performance. Under certain synthesis conditions, unique nanoscale AuNPs/PEDOT:PSS core-shell structures could also be produced, indicating the interaction at the AuNPs/polymer interface. The enhanced catalytic activity shown by AuNPs/PEDOT:PSS has been attributed to the effective electron transfer and reactive species diffusion through the porous polymer network, as well as the synergistic interfacial interaction at the metal/polymer and metal/metal interfaces.

  9. Gold nanoparticle-polymer nanocomposites synthesized by room temperature atmospheric pressure plasma and their potential for fuel cell electrocatalytic application

    PubMed Central

    Zhang, Ri-Chao; Sun, Dan; Zhang, Ruirui; Lin, Wen-Feng; Macias-Montero, Manuel; Patel, Jenish; Askari, Sadegh; McDonald, Calum; Mariotti, Davide; Maguire, Paul

    2017-01-01

    Conductive polymers have been increasingly used as fuel cell catalyst support due to their electrical conductivity, large surface areas and stability. The incorporation of metal nanoparticles into a polymer matrix can effectively increase the specific surface area of these materials and hence improve the catalytic efficiency. In this work, a nanoparticle loaded conductive polymer nanocomposite was obtained by a one-step synthesis approach based on room temperature direct current plasma-liquid interaction. Gold nanoparticles were directly synthesized from HAuCl4 precursor in poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). The resulting AuNPs/PEDOT:PSS nanocomposites were subsequently characterized under a practical alkaline direct ethanol fuel cell operation condition for its potential application as an electrocatalyst. Results show that AuNPs sizes within the PEDOT:PSS matrix are dependent on the plasma treatment time and precursor concentration, which in turn affect the nanocomposites electrical conductivity and their catalytic performance. Under certain synthesis conditions, unique nanoscale AuNPs/PEDOT:PSS core-shell structures could also be produced, indicating the interaction at the AuNPs/polymer interface. The enhanced catalytic activity shown by AuNPs/PEDOT:PSS has been attributed to the effective electron transfer and reactive species diffusion through the porous polymer network, as well as the synergistic interfacial interaction at the metal/polymer and metal/metal interfaces. PMID:28436454

  10. [An investigation of HAP/organic polymer composite coatings prepared by electrochemical co-deposition technique].

    PubMed

    Hu, Haobing; Lin, Changjian; Leng, Yang

    2003-03-01

    An electrochemical co-deposition technique has been developed to prepare a hydroxyapatite (HAP)/organic polymer composite coatings on Ti surface as new biomaterial of hard tissue. The composite coating of organic polymer and calcium phosphate is formed by adding a water soluble polymer of the ethylene series to NH4H2PO4-Ca (NO3)2 solution when conducting an appropriate electrochemical co-deposition experiment. The XRD, SEM, XPS, SIMS and nano indent measurements were performed to characterize the morphology, composition, structure and surface stiffness of the composite coating. It was found that the morphology and surface hardness of the coatings showed a remarkable modification when introducing a minor polymer to HAP coating, and the bonding force between the coating and metal substrate was distinctly increased. The incorporation of minor organic polymer into the HAP compound at molecular level will improve the mechanical properties and morphology of the composite coatings, and this may be helpful to raising its bio-activity.

  11. Recent progress of high performance polymer OLED and OPV materials for organic printed electronics

    NASA Astrophysics Data System (ADS)

    Sekine, Chizu; Tsubata, Yoshiaki; Yamada, Takeshi; Kitano, Makoto; Doi, Shuji

    2014-06-01

    The development of organic printed electronics has been expanding to a variety of applications and is expected to bring innovations to our future life. Along with this trend, high performance organic materials with cost-efficient fabrication processes and specific features such as thin, light weight, bendable, and low power consumption are required. A variety of organic materials have been investigated in the development of this field. The basic guidelines for material design and the recent progress of polymer-based organic light-emitting diodes (OLEDs) and organic photovoltaic cells (OPVs) are reported.

  12. Recent progress of high performance polymer OLED and OPV materials for organic printed electronics

    PubMed Central

    Sekine, Chizu; Tsubata, Yoshiaki; Yamada, Takeshi; Kitano, Makoto; Doi, Shuji

    2014-01-01

    The development of organic printed electronics has been expanding to a variety of applications and is expected to bring innovations to our future life. Along with this trend, high performance organic materials with cost-efficient fabrication processes and specific features such as thin, light weight, bendable, and low power consumption are required. A variety of organic materials have been investigated in the development of this field. The basic guidelines for material design and the recent progress of polymer-based organic light-emitting diodes (OLEDs) and organic photovoltaic cells (OPVs) are reported. PMID:27877671

  13. Recent progress of high performance polymer OLED and OPV materials for organic printed electronics.

    PubMed

    Sekine, Chizu; Tsubata, Yoshiaki; Yamada, Takeshi; Kitano, Makoto; Doi, Shuji

    2014-06-01

    The development of organic printed electronics has been expanding to a variety of applications and is expected to bring innovations to our future life. Along with this trend, high performance organic materials with cost-efficient fabrication processes and specific features such as thin, light weight, bendable, and low power consumption are required. A variety of organic materials have been investigated in the development of this field. The basic guidelines for material design and the recent progress of polymer-based organic light-emitting diodes (OLEDs) and organic photovoltaic cells (OPVs) are reported.

  14. Chromosome-like organization of an asymmetrical ring polymer confined in a cylindrical space.

    PubMed

    Jeon, Chanil; Kim, Juin; Jeong, Hawoong; Jung, Youngkyun; Ha, Bae-Yeun

    2015-11-07

    To what extent does a confined polymer show chromosome-like organization? Using molecular dynamics simulations, we study a model Escherichia coli (E. coli) chromosome: an asymmetrical ring polymer, formed by small monomers on one side and big monomers on the other confined in a concentric-shell or simple cylinder with closed ends. The ring polymer is organized in the way observed for the E. coli chromosome: if the big monomers are assumed to be localized in the inner cylinder, the two "subchains" forming the ring are spontaneously partitioned in a parallel orientation with the "body" (big-monomer) chain linearly organized with a desired precision and the crossing (small-monomer) chain residing preferentially in the peripheral region. Furthermore, we show that the introduction of a "fluctuating boundary" between the two subchains leads to a double-peak distribution of ter-proximate loci, as seen in experiments, which would otherwise remain single-peaked. In a simple cylinder, however, a chromosome-like organization of the ring polymer typically requires an external mechanism such as cell-wall attachment. Finally, our results clarify to what degree the spatial organization of the chromosomes can be accomplished solely by ring asymmetry and anisotropic confinement.

  15. The Relationship Between Chemical Structure and Dielectric Properties of Plasma-Enhanced Chemical Vapor Deposited Polymer Thin Films (Postprint)

    DTIC Science & Technology

    2007-01-01

    Materials Sci & Tech Applications, LLC) N. Venkatasubramanian and John T. Grant (University of Dayton) Kurt Eyink, Jesse Enlow, and Timothy J. Bunning...structure and dielectric properties of plasma-enhanced chemical vapor deposited polymer thin films Hao Jiang b,⁎, Lianggou Hong b, N. Venkatasubramanian c

  16. RMS roughness-independent tuning of surface wettability by tailoring silver nanoparticles with a fluorocarbon plasma polymer.

    PubMed

    Choukourov, A; Kylián, O; Petr, M; Vaidulych, M; Nikitin, D; Hanuš, J; Artemenko, A; Shelemin, A; Gordeev, I; Kolská, Z; Solař, P; Khalakhan, I; Ryabov, A; Májek, J; Slavínská, D; Biederman, H

    2017-02-16

    A layer of 14 nm-sized Ag nanoparticles undergoes complex transformation when overcoated by thin films of a fluorocarbon plasma polymer. Two regimes of surface evolution are identified, both with invariable RMS roughness. In the early regime, the plasma polymer penetrates between and beneath the nanoparticles, raising them above the substrate and maintaining the multivalued character of the surface roughness. The growth (β) and the dynamic (1/z) exponents are close to zero and the interface bears the features of self-affinity. The presence of inter-particle voids leads to heterogeneous wetting with an apparent water contact angle θa = 135°. The multivalued nanotopography results in two possible positions for the water droplet meniscus, yet strong water adhesion indicates that the meniscus is located at the lower part of the spherical nanofeatures. In the late regime, the inter-particle voids become filled and the interface acquires a single valued character. The plasma polymer proceeds to grow on the thus-roughened surface whereas the nanoparticles keep emerging away from the substrate. The RMS roughness remains invariable and lateral correlations propagate with 1/z = 0.27. The surface features multiaffinity which is given by different evolution of length scales associated with the nanoparticles and with the plasma polymer. The wettability turns to the homogeneous wetting state.

  17. Polaron spin echo envelope modulations in an organic semiconducting polymer

    DOE PAGES

    Mkhitaryan, V. V.; Dobrovitski, V. V.

    2017-06-01

    Here, we present a theoretical analysis of the electron spin echo envelope modulation (ESEEM) spectra of polarons in semiconducting π -conjugated polymers. We show that the contact hyperfine coupling and the dipolar interaction between the polaron and the proton spins give rise to different features in the ESEEM spectra. Our theory enables direct selective probe of different groups of nuclear spins, which affect the polaron spin dynamics. Namely, we demonstrate how the signal from the distant protons (coupled to the polaron spin via dipolar interactions) can be distinguished from the signal coming from the protons residing on the polaron sitemore » (coupled to the polaron spin via contact hyperfine interaction). We propose a method for directly probing the contact hyperfine interaction, that would enable detailed study of the polaron orbital state and its immediate environment. Lastly, we also analyze the decay of the spin echo modulation, and its connection to the polaron transport.« less

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Formation of a Syndiotactic Organic Polymer Inside a MOF by a [2+2] Photo-Polymerization Reaction.

    PubMed

    Park, In-Hyeok; Medishetty, Raghavender; Lee, Hyeong-Hwan; Mulijanto, Caroline Evania; Quah, Hong Sheng; Lee, Shim Sung; Vittal, Jagadese J

    2015-06-15

    Getting suitable crystals for single-crystal X-ray crystallographic analysis still remains an art. Obtaining single crystals of metal-organic frameworks (MOFs) containing organic polymers poses even greater challenges. Here we demonstrate the formation of a syndiotactic organic polymer ligand inside a MOF by quantitative [2+2] photopolymerization reaction in a single-crystal-to-single-crystal manner. The spacer ligands with trans,trans,trans-conformation in the pillared-layer MOF with guest water molecules in the channels, undergo pedal motion to trans,cis,trans-conformation prior to [2+2] photo-cycloaddition reaction and yield single crystals of MOF containing two-dimensional coordination polymers fused with the organic polymer ligands. We also show that the organic polymer in the single crystals can be depolymerized reversibly by cleaving the cyclobutane rings upon heating. These MOFs also show interesting photoluminescent properties and sensing of small organic molecules.

  3. Surface activation of cyclo olefin polymer by oxygen plasma discharge: a molecular dynamics study

    NASA Astrophysics Data System (ADS)

    Soberon, Felipe

    2014-07-01

    Thermoplastic substrates made of cyclo olefin polymer (COP) are treated with oxygen plasma discharges to introduce polar groups at the surface. This is the first step in the process of surface functionalization of COP substrates used in biosensor devices. A molecular dynamics model of basic COP structure is implemented using the second-generation reactive empirical bond order (REBO) potentials for hydrocarbon-oxygen interactions. The model includes covalent bond and Van der Waals interactions. The bombardment of a COP surface with mono-energetic atomic oxygen ions, energy in the range 1-35 eV, is simulated and reported here. The dynamics of the substrate modification reveals that the substrate top layer is de-hydrogenated and subsequently builds up an oxygen-carbon matrix layer, ˜10 Å thick. Analysis of the modified substrates indicates that surface yield is predominantly peroxide groups.

  4. Floating-Gate Type Organic Memory with Organic Insulator Thin Film of Plasma Polymerized Methyl Methacrylate

    NASA Astrophysics Data System (ADS)

    Kim, Hee-sung; Lee, Boong-Joo; Kim, Gun-Su; Shin, Paik-Kyun

    2013-02-01

    To fabricate organic memory device by entirely dry process, plasma polymerized methyl methacrylate (ppMMA) thin films were prepared and they were used as both tunneling layer and gate insulator layer in a floating-gate type organic memory device. The ppMMA thin films were prepared with inductively coupled plasma (ICP) source combined with stabilized monomer vapor control. The ppMMA gate insulator thin film revealed dielectric constant of 3.75 and low leakage current of smaller than 10-9 A/cm. The floating-gate type organic memory device showed promising memory characteristics such as memory window value of 12 V and retention time of over 2 h, where 60 V of writing voltage and -30 V of erasing voltage were applied, respectively.

  5. Plasma immersion ion implantation of polyurethane shape memory polymer: Surface properties and protein immobilization

    NASA Astrophysics Data System (ADS)

    Cheng, Xinying; Kondyurin, Alexey; Bao, Shisan; Bilek, Marcela M. M.; Ye, Lin

    2017-09-01

    Polyurethane-type shape memory polymers (SMPU) are promising biomedical implant materials due to their ability to recover to a predetermined shape from a temporary shape induced by thermal activation close to human body temperature and their advantageous mechanical properties including large recovery strains and low recovery stresses. Plasma Immersion Ion Implantation (PIII) is a surface modification process using energetic ions that generates radicals in polymer surfaces leading to carbonisation and oxidation and the ability to covalently immobilise proteins without the need for wet chemistry. Here we show that PIII treatment of SMPU significantly enhances its bioactivity making SMPU suitable for applications in permanent implantable biomedical devices. Scanning Electron Microscopy (SEM), contact angle measurements, surface energy measurements, attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) were used to characterise the PIII modified surface, including its after treatment aging kinetics and its capability to covalently immobilise protein directly from solution. The results show a substantial improvement in wettability and dramatic changes of surface chemical composition dependent on treatment duration, due to the generation of radicals and subsequent oxidation. The SMPU surface, PIII treated for 200s, achieved a saturated level of covalently immobilized protein indicating that a full monolayer coverage was achieved. We conclude that PIII is a promising and efficient surface modification method to enhance the biocompatibility of SMPU for use in medical applications that demand bioactivity for tissue integration and stability in vivo.

  6. 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.

  7. Activation energies of diffusion of organic migrants in cyclo olefin polymer.

    PubMed

    Welle, Frank

    2014-10-01

    Cyclo olefin polymer (COP) is an amorphous polymer with good optical transparency and barrier properties, which is increasingly used for pharmaceutical packaging applications like pre-filled syringes, plastic vials, nutrition bags and blisters as well as for micro-well plates. For regulatory purposes, it is important to know the amount and quantity of compounds which migrate from the polymer into the pharmaceutical product. Within the study, diffusion coefficients of organic (model) compounds in COP at various temperatures were determined and the activation energies of diffusion were calculated according to the Arrhenius approach. Correlations were established between the molecular volume V of the migrating compound and the activation energy of diffusion EA as well as between the pre-exponential factor in the Arrhenius equation D0 and EA. From these correlations a prediction model was established for the migration of organic compounds in COP. This might be a useful tool supporting the evaluation process of COP packed pharmaceutical products.

  8. 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

  9. Microporous organic polymers with ketal linkages: synthesis, characterization, and gas sorption properties.

    PubMed

    Han, Ying; Zhang, Li-Min; Zhao, Yan-Chao; Wang, Tao; Han, Bao-Hang

    2013-05-22

    A series of microporous organic polymers with ketal linkages were synthesized based on the condensation of aromatic acetyl monomers with pentaerythritol. Fourier transform infrared and solid-state cross-polarization/magic-angle-spinning (13)C NMR spectroscopy were utilized to confirm the ketal linkages of the resulting polymers. The morphology can be observed from scanning electron microscopy and transmission electron microscopy images. The materials possess Brunauer-Emmet-Teller specific surface area values ranging from 520 to 950 m(2) g(-1), and the highest hydrogen sorption capacity is up to 1.96 wt % (77 K and 1.0 bar), which is superior to that of most of microporous organic polymers. The facile and cost-effective preparation process and excellent gas sorption properties make these kinds of materials promising candidates for practical applications.

  10. 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.

  11. Current Sheet Formation and Self-Organization in Turbulent Plasmas

    NASA Astrophysics Data System (ADS)

    Spangler, Steven

    2009-05-01

    Self-Organization can be defined as the process by which a physical system, in the course of its evolution, changes its spatial structure, the form of its equations of motion, or key coefficients in those equations. A turbulent magnetohydrodynamic (MHD) fluid can exhibit self-organization, so defined. A turbulent MHD fluid with collisional resistivity has a low rate of dissipation of turbulent energy. However, as the turbulence develops, it forms thin current sheets in which the current density increases exponentially. When the electron drift speed becomes comparable to or exceeds the ion acoustic speed, plasma instabilities can enhance the resistivity, and thus the dissipation rate. In turbulent evolution of this kind, an MHD fluid can transform itself from a low dissipation to a high dissipation state. Calculations show that it is plausible that turbulence in the solar corona could exhibit this behavior.

  12. 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.

  13. 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.

  14. Designed synthesis of nanoporous organic polymers for selective gas uptake and catalytic applications

    NASA Astrophysics Data System (ADS)

    Arab, Pezhman

    Design and synthesis of porous organic polymers have attracted considerable attentions during the past decade due to their wide range of applications in gas storage, gas separation, energy conversion, and catalysis. Porous organic polymers can be pre-synthetically and post-synthetically functionalized with a wide variety of functionalities for desirable applications. Along these pursuits, we introduced new synthetic strategies for preparation of porous organic polymers for selective CO2 capture and catalytic applications. Porous azo-linked polymers (ALPs) were synthesized by an oxidative reaction of amine-based monomers using copper(I) as a catalyst which leads to azo-linkage formation. ALPs exhibit high surface areas of up to 1200 m2 g-1 and have high chemical and thermal stabilities. The nitrogen atoms of the azo group can act as Lewis bases and the carbon atom of CO2 can act as a Lewis acid. Therefore, ALPs show high CO2 uptake capacities due to this Lewis acid-based interaction. The potential applications of ALPs for selective CO2 capture from flue gas, natural gas, and landfill gas under pressure-swing and vacuum swing separation settings were studied. Due to their high CO2 uptake capacity, selectivity, and regenerability, ALPs are among the best porous organic frameworks for selective CO2 capture. In our second project, a new bis(imino)pyridine-linked porous polymer (BIPLP-1) was synthesized and post-synthetically functionalized with Cu(BF4)2 for highly selective CO2 capture. BIPLP-1 was synthesized via a condensation reaction between 2,6-pyridinedicarboxaldehyde and 1,3,5-tris(4-aminophenyl)benzene, wherein the bis(imino)pyridine linkages are formed in-situ during polymerization. The functionalization of the polymer with Cu(BF4)2 was achieved by treatment of the polymer with a solution of Cu(BF4)2 via complexation of copper cations with bis(imino)pyridine moieties of the polymer. BF4- ions can act Lewis base and CO2 can act as a Lewis acid; and therefore

  15. Non-thermal plasma techniques for abatement of volatile organic compounds and nitrogen oxides

    SciTech Connect

    Penetrante, B.M.; Hsiao, M.C.; Bardsley, J.N.; Merritt, B.T.; Vogtlin, G.E.; Wallman, P.H.; Kuthi, A.; Burkhart, C.P.; Bayless, J.R.

    1995-12-04

    Non-thermal plasma processing is an emerging technology for the abatement of volatile organic compounds (VOCs) and nitrogen oxides (NO{sub x}) in atmospheric-pressure air streams. Either electrical discharge or electron beam methods can produce these plasmas. Each of these methods can be implemented in many ways. There are many types of electrical discharge reactors, the variants depending on the electrode configuration and electrical power supply (pulsed, AC or DC). Two of the more extensively investigated types of discharge reactors are based on the pulsed corona and dielectric-barrier discharge. Recently, compact low-energy (<200 keV) electron accelerators have been developed to meet the requirements of industrial applications such as crosslinking of polymer materials, curing of solvent-free coatings, and drying of printing inks. Special materials have also been developed to make the window thin and rugged. Some of these compact electron beam sources are already commercially available and could be utilized for many pollution control applications. In this paper we will present a comparative assessment of various nonthermal plasma reactors. The thrust of our work has been two-fold: (1) to understand the scalability of various non-thermal plasma reactors by focusing on the energy efficiency of the electron and chemical kinetics, and (2) to identify the byproducts to ensure that the effluent gases from the processor are either benign or much easier and less expensive to dispose of compared to the original pollutants. We will present experimental results using a compact electron beam reactor and various types of electrical discharge reactors. We have used these reactors to study the removal of NO{sub x} and a wide variety of VOCS. We have studied the effects of background gas composition and gas temperature on the decomposition chemistry.

  16. 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

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

    SciTech Connect

    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 m2 g–1, and a broad range of pore volumes of 0.24–3.50 cm3 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

  18. 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.

  19. 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.

  20. New way of polymer design for organic solar cells using the quinoid structure

    NASA Astrophysics Data System (ADS)

    Berube, Nicolas; Gaudreau, Josiane; Cote, Michel

    2013-03-01

    Research in organic photovoltaic applications are receiving a great interest as they offer an environmentally clean and low-cost solution to the world's rising energy needs. Controlling the device's active polymer optical bandgap is an important step that affects its absorption of the solar spectrum, and ultimately, its power conversion efficiency. The use of fused heterocycles that favors the polymer's quinoid structure has been a known method to lower the bandgap, for example, with isothianapthene, but there is a lack of quantifiable data on this effect. Density functional theory (DFT) calculations were done on over 60 polymers with bandgaps between 0.5 eV and 4 eV. They clearly show that low bandgaps are observed in copolymers that carefully stands between their quinoid and aromatic structures. Such balance can be obtained by mixing monomer units with quinoid characteristics with aromatic ones. Time-dependant DFT results also links low bandgaps with lower reorganization energy, which means that polymers with this structural form could possess higher charge mobilities. This link between the geometrical structure and the bandgap is compatible with a vast variety of polymers and is more convincing than the commonly used donor-acceptor method of polymer design.

  1. Gate-Bias Stability Behavior Tailored by Dielectric Polymer Stereostructure in Organic Transistors.

    PubMed

    Lee, Junghwi; Min, Honggi; Park, Namwoo; Jeong, Heejeong; Han, Singu; Kim, Se Hyun; Lee, Hwa Sung

    2015-11-18

    Understanding charge trapping in a polymer dielectric is critical to the design of high-performance organic field-effect transistors (OFETs). We investigated the OFET stability as a function of the dielectric polymer stereostructure under a gate bias stress and during long-term operation. To this end, iso-, syn-, and atactic poly(methyl methacrylate) (PMMA) polymers with identical molecular weights and polydispersity indices were selected. The PMMA stereostructure was found to significantly influence the charge trapping behavior and trap formation in the polymer dielectrics. This influence was especially strong in the bulk region rather than in the surface region. The regular configurational arrangements (isotactic > syntactic > atactic) of the pendant groups on the PMMA backbone chain facilitated closer packing between the polymer interchains and led to a higher crystallinity of the polymer dielectric, which caused a reduction in the free volumes that act as sites for charge trapping and air molecule absorption. The PMMA dielectrics with regular stereostructures (iso- and syn-stereoisomers) exhibited more stable OFET operation under bias stress compared to devices prepared using irregular a-PMMA in both vacuum and air.

  2. Partitioning of hydrophobic organic contaminants between polymer and lipids for two silicones and low density polyethylene.

    PubMed

    Smedes, Foppe; Rusina, Tatsiana P; Beeltje, Henry; Mayer, Philipp

    2017-08-11

    Polymers are increasingly used for passive sampling of neutral hydrophobic organic substances (HOC) in environmental media including water, air, soil, sediment and even biological tissue. The equilibrium concentration of HOC in the polymer can be measured and then converted into equilibrium concentrations in other (defined) media, which however requires appropriate polymer to media partition coefficients. We determined thus polymer-lipid partition coefficients (KPL) of various PCB, PAH and organochlorine pesticides by equilibration of two silicones and low density polyethylene (LDPE) with fish oil and Triolein at 4 °C and 20 °C. We observed (i) that KPL was largely independent of lipid type and temperature, (ii) that lipid diffusion rates in the polymers were higher compared to predictions based on their molecular volume, (iii) that silicones showed higher lipid diffusion and lower lipid sorption compared to LDPE and (iv) that absorbed lipid behaved like a co-solute and did not affect the partitioning of HOC at least for the smaller molecular size HOC. The obtained KPL can convert measured equilibrium concentrations in passive sampling polymers into equilibrium concentrations in lipid, which then can be used (1) for environmental quality monitoring and assessment, (2) for thermodynamic exposure assessment and (3) for assessing the linkage between passive sampling and the traditionally measured lipid-normalized concentrations in biota. LDPE-lipid partition coefficients may also be of use for a thermodynamically sound risk assessment of HOC contained in microplastics. Copyright © 2017. Published by Elsevier Ltd.

  3. Massive preparation of pitch-based organic microporous polymers for gas storage.

    PubMed

    Li, Wenqing; Zhang, Aijuan; Gao, Hui; Chen, Mingjie; Liu, Anhua; Bai, Hua; Li, Lei

    2016-02-14

    A general challenge for preparing organic microporous polymers (MOPs) is to use cheap and sustainable building blocks while retaining the advanced functions. We demonstrate a strategy to massively prepare pitch-based MOPs, which are thermally and chemically stable. A maximum BET surface area of 758 m(2) g(-1) and high gas storage capacity were achieved.

  4. Polymer-based MEMS accelerometer with modified organic electronics and thin film transistor

    NASA Astrophysics Data System (ADS)

    Varadan, Vijay K.

    2003-04-01

    Polymer based MEMS is rapidly gaining momentum due to their potential for conformability and other special characteristics not available with silicon microsystems. The polymer based nano- and micro-devices are flexible, chemically and biologically compatible, available in many varieties, and can be fabricated in truly 3-D shapes. The conceived devices thus are cheap and disposable. However, in order to conceive fully functional microsystems, necessary electronics have to be integrated. A modified organic thin film TFT is used for such integration. Although the existing technology of organic TFTs can not rival the well-established silicon semiconductor technology, especially in terms of speed, they are still useful in displays, disposable devices, and sensors. Although organic TFT and polymeric MEMS have several common features that make them compatible with each other, to the best of our knowledge, no serious attempt has been made thus far for combining these technologies. This paper is aimed at bridging this gap. Examples of potential micro sensors and systems, such as accelerometers and gyroscopes derived from polymer with functionalised carbon nanotubes are presented. A sensor-in-shoe demonstration will be performed at the Conference. Many issues and challenges in the design and development of polymer-based sensors with organic electronics are also addressed.

  5. Polymer- and carbon nanotube-based MEMS accelerometer with modified organic electronics and thin film transistor

    NASA Astrophysics Data System (ADS)

    Varadan, Vijay K.

    2003-07-01

    Polymer based MEMS is rapidly gaining momentum due to their potential for conformability and other special characteristics not available with silicon microsystems. The polymer based nano- and micro-devices are flexible, chemically and biologically compatible, available in many varieties, and can be fabricated in truly 3-D shapes. The conceived devices thus are cheap and disposable. However, in order to conceive fully functional microsystems, necessary electronics have to be integrated. A modified organic thin film TFT is used for such integration. Although the existing technology of organic TFTs can not rival the well-established silicon semiconductor technology, especially in terms of speed, they are still useful in displays, disposable devices, and sensors. Although organic TFT and polymeric MEMS have several common features that make them compatible with each other, to the best of our knowledge, no serious attempt has been made thus far for combining these technologies. This paper is aimed at bridging this gap. Examples of potential microsensors and systems, such as accelerometers and gyroscopes derived from polymer with functionalised carbon nanotubes are presented. A sensor-in-shoe demonstration will be performed at the Conference. Many issues and challenges in the design and development of polymer-based sensors with organic electronics are also addressed.

  6. Click-chemistry approaches to π-conjugated polymers for organic electronics applications

    PubMed Central

    Facchetti, Antonio; Lanari, Daniela; Santoro, Stefano

    2016-01-01

    Given the wide utility of click-chemistry reactions for the preparation of simple moieties within large architecturally complex materials, this minireview article aims at surveying papers exploring their scope in the area of π-conjugated polymers for application in organic electronics to enable advanced functional properties. PMID:28567241

  7. New Type of Metallo-Organic Polymer: Bimetalloporphyrins. Investigating a New Chemistry of Metallophthalocyanines.

    DTIC Science & Technology

    1981-01-01

    this complex is known to play an important role in the electrochromic 7 properties. Although an obvious distortion from macrocyclic planarity (13...Ii necosoary and identify by block number) Metallo-organic polymer, Bimetalloporphyrins, Metallophthalocyanines Sitting atop complex ,- [meso...tetraphenylporphinatolbis [tricarbonylrhenium(l) ], monoca- S tion octaethyl(porphiyrin tri-u- halogeno-hexacronyl-dirhenate(I), Skewered complex , radical

  8. Prompt response and durability of polymer ablation from synthetic fibers irradiated by thermal plasmas for arc resistant clothes

    NASA Astrophysics Data System (ADS)

    Ishida, Masahiro; Shinsei, Naoki; Tanaka, Yasunori; Uesugi, Yoshihiko; Ishijima, Tatsuo; Mio, Wataru; Hagi, Hiroyasu; Uchibori, Keita

    2013-06-01

    Interactions between thermal plasmas and synthetic fibers such as polyamide, polyester, phenol and aramid were investigated by thermal plasma irradiation technique. Understanding the above interactions is crucial to design effective flame retardant synthetic fiber clothes with arc resistance to protect a human from arc flash accidents. To investigate the interactions, an Ar inductively coupled thermal plasma (ICTP) was used instead of the arc discharge because the ICTP has high controllability and no contamination. The ICTP irradiation raises polymer ablation in case of polyamide and polyester. Two features of the polymer ablation such as prompt response and durability were fundamentally investigated from viewpoint of shielding the heat flux. It was found that polyamide fiber has both a high prompt response and a long durability.

  9. Polymer dielectric materials for organic thin-film transistors: Interfacial control and development for printable electronics

    NASA Astrophysics Data System (ADS)

    Kim, Choongik

    Organic thin-film transistors (OTFTs) have been extensively studied for organic electronics. In these devices, organic semiconductor-dielectric interface characteristics play a critical role in influencing OTFT operation and performance. This study begins with exploring how the physicochemical characteristics of the polymer gate dielectric affects the thin-film growth mode, microstructure, and OTFT performance parameters of pentacene films deposited on bilayer polymer (top)-SiO2 (bottom) dielectrics. Pentacene growth mode varies considerably with dielectric substrate, and correlations are established between pentacene film deposition temperature, the thin-film to bulk microstructural phase transition, and OTFT device performance. Furthermore, the primary influence of the polymer dielectric layer glass transition temperature on pentacene film microstructure and OTFT response is shown for the first time. Following the first study, the influence of the polymer gate dielectric viscoelastic properties on overlying organic semiconductor film growth, film microstructure, and TFT response are investigated in detail. From the knowledge that nanoscopically-confined thin polymer films exhibit glass transition temperatures that deviate substantially from those of the corresponding bulk materials, pentacene (p-channel) and cyanoperylene (n-channel) films grown on polymer gate dielectrics at temperatures well-below their bulk glass transition temperatures (Tg(b)) have been shown to exhibit morphological/microstructural transitions and dramatic OTFT performance discontinuities at well-defined temperatures (defined as the polymer "surface glass transition temperature," or Tg(s)). These transitions are characteristic of the particular polymer architecture and independent of film thickness or overall film cooperative chain dynamics. Furthermore, by analyzing the pentacene films grown on UV-curable polymer dielectrics with different curing times (hence, different degrees of

  10. Gate-induced superconductivity in a solution-processed organic polymer film

    NASA Astrophysics Data System (ADS)

    Schön, J. H.; Dodabalapur, A.; Bao, Z.; Kloc, Ch.; Schenker, O.; Batlogg, B.

    2001-03-01

    The electrical and optical properties of conjugated polymers have received considerable attention in the context of potentially low-cost replacements for conventional metals and inorganic semiconductors. Charge transport in these organic materials has been characterized in both the doped-metallic and the semiconducting state, but superconductivity has not hitherto been observed in these polymers. Here we report a distinct metal-insulator transition and metallic levels of conductivity in a polymer field-effect transistor. The active material is solution-cast regioregular poly(3-hexylthiophene), which forms relatively well ordered films owing to self-organization, and which yields a high charge carrier mobility (0.05-0.1cm2V-1s-1) at room temperature. At temperatures below ~2.35K with sheet carrier densities exceeding 2.5 × 1014cm-2, the polythiophene film becomes superconducting. The appearance of superconductivity seems to be closely related to the self-assembly properties of the polymer, as the introduction of additional disorder is found to suppress superconductivity. Our findings therefore demonstrate the feasibility of tuning the electrical properties of conjugated polymers over the largest range possible-from insulating to superconducting.

  11. 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

    2013-04-02

    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.

  12. Antifungal coatings by caspofungin immobilization onto biomaterials surfaces via a plasma polymer interlayer.

    PubMed

    Griesser, Stefani S; Jasieniak, Marek; Coad, Bryan R; Griesser, Hans J

    2015-12-14

    Not only bacteria but also fungal pathogens, particularly Candida species, can lead to biofilm infections on biomedical devices. By covalent grafting of the antifungal drug caspofungin, which targets the fungal cell wall, onto solid biomaterials, a surface layer can be created that might be able to provide long-term protection against fungal biofilm formation. Plasma polymerization of propionaldehyde (propanal) was used to deposit a thin (∼20 nm) interfacial bonding layer bearing aldehyde surface groups that can react with amine groups of caspofungin to form covalent interfacial bonds for immobilization. Surface analyses by x-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry confirmed the intended grafting and uniformity of the coatings, and durability upon extended washing. Testing for fungal cell attachment and ensuing biofilm formation showed that caspofungin retained activity when covalently bound onto surfaces, disrupting colonizing Candida cells. Mammalian cytotoxicity studies using human primary fibroblasts indicated that the caspofungin-grafted surfaces were selective in eliminating fungal cells while allowing attachment and spreading of mammalian cells. These in vitro data suggest promise for use as antifungal coatings, for example, on catheters, and the use of a plasma polymer interlayer enables facile transfer of the coating method onto a wide variety of biomaterials and biomedical devices.

  13. Optimum condition of anisotropic plasma etching for improving bending properties of ionic polymer-metal composites.

    PubMed

    Choi, N J; Lee, H K; Jung, S; Park, K H

    2010-05-01

    We presented an anisotropic plasma etching technique by reactive ion etcher (RIE) as a new pretreatment method of fabrication of ionic polymer-metal composite (IPMC). We already found that the new technique provided large displacement to the fabricated IPMC in the presence of low applied voltage. However, we did not examine the optimum condition for the anisotropic plasma etching. In this research, we tried to figure out optimum treatment condition of film in etcher. Nafion (by DuPont) films were etched using various etching time and shadow masks with various slit and space sizes. The etched samples were plated with Pt at top and bottom side by Oguro's reduction method. The surface morphology of fabricated IPMCs was characterized by SEM. And, we've measured surface resistance, bending displacement, and driving force in order to check the IPMC properties out. Here, we found that optimum condition for pre-treatment of Nafion was 1 min for etching time under shadow mask with 200 microm slit and 100 microm space.

  14. 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.

  15. Plasma immersion ion implantation modification of surface properties of polymer material

    SciTech Connect

    Husein, I.F.; Zhou, Y.; Qin, S.; Chan, C.; Marchev, K.; Kleiman, J.I.

    1997-12-01

    The use of plasma immersion ion implantation (PIII) as a novel method for the treatment of polymer surfaces is investigated. The effect of PIII treatment on the coefficient of friction, contact angle modification, and surface energy of silicone and EPDM (ethylene-propylene-diene monomer) rubber are investigated as a function of pulse voltage, treatment time, and gas species. Low energy (0--8 keV) and high dose ({approximately}10{sup 17}--10{sup 18} ions/cm{sup 2}) implantation of N{sub 2}, Ar, and CF{sub 4} is performed using an inductively coupled plasma source (ICP) at low pressure (0.2 mTorr). PIII treatment reduces the coefficient of friction ({micro}) of silicone rubber from {mu} = 0.464 to the range {mu} = 0.176--0.274, and {mu} of EPDM rubber decreases from 0.9 to the range {mu} = 0.27--0.416 depending on processing conditions. The contact angle of water and diiodomethylene decreases after implantation and increases at higher doses for both silicone and EPDM rubber.

  16. Nanoscale investigations on interchain organization in thin films of polymer-liquid crystal blend

    NASA Astrophysics Data System (ADS)

    Villeneuve-Faure, C.; Le Borgne, D.; Ventalon, V.; Seguy, I.; Moineau-Chane Ching, K. I.; Bedel-Pereira, E.

    2017-07-01

    Optimized nanomorphology in organic thin active layers is crucial for good performance in organic solar cells. However, the relation between morphology and electronic properties at nanoscale remains not completely understood. Here, we study the effect of film thickness and temperature annealing on the ordering of poly(3-hexylthiophene) chains when the polymer is blended with a columnar liquid crystalline molecule. Electronic absorption, atomic force microscopy measurements, and Raman spectroscopy show that morphology and chain ordering of the blend depend on the film thickness. We highlight the benefit of using a liquid crystal in organic blends, opening the way to use simple processing methods for the fabrication of organic electronic devices.

  17. Aqueous Processing for Printed Organic Electronics: Conjugated Polymers with Multistage Cleavable Side Chains.

    PubMed

    Schmatz, Brian; Yuan, Zhibo; Lang, Augustus W; Hernandez, Jeff L; Reichmanis, Elsa; Reynolds, John R

    2017-09-27

    The ability to process conjugated polymers via aqueous solution is highly advantageous for reducing the costs and environmental hazards of large scale roll-to-roll processing of organic electronics. However, maintaining competitive electronic properties while achieving aqueous solubility is difficult for several reasons: (1) Materials with polar functional groups that provide aqueous solubility can be difficult to purify and characterize, (2) many traditional coupling and polymerization reactions cannot be performed in aqueous solution, and (3) ionic groups, though useful for obtaining aqueous solubility, can lead to a loss of solid-state order, as well as a screening of any applied bias. As an alternative, we report a multistage cleavable side chain method that combines desirable aqueous processing attributes without sacrificing semiconducting capabilities. Through the attachment of cleavable side chains, conjugated polymers have for the first time been synthesized, characterized, and purified in organic solvents, converted to a water-soluble form for aqueous processing, and brought through a final treatment to cleave the polymer side chains and leave behind the desired electronic material as a solvent-resistant film. Specifically, we demonstrate an organic soluble polythiophene that is converted to an aqueous soluble polyelectrolyte via hydrolysis. After blade coating from an aqueous solution, UV irradiation is used to cleave the polymer's side chains, resulting in a solvent-resistant, electroactive polymer thin film. In application, this process results in aqueous printed materials with utility for solid-state charge transport in organic field effect transistors (OFETs), along with red to colorless electrochromism in ionic media for color changing displays, demonstrating its potential as a universal method for aqueous printing in organic electronics.

  18. Room temperature phosphorescence of metal-free organic materials in amorphous polymer matrices.

    PubMed

    Lee, Dongwook; Bolton, Onas; Kim, Byoung Choul; Youk, Ji Ho; Takayama, Shuichi; Kim, Jinsang

    2013-04-24

    Developing metal-free organic phosphorescent materials is promising but challenging because achieving emissive triplet relaxation that outcompetes the vibrational loss of triplets, a key process to achieving phosphorescence, is difficult without heavy metal atoms. While recent studies reveal that bright room temperature phosphorescence can be realized in purely organic crystalline materials through directed halogen bonding, these organic phosphors still have limitations to practical applications due to the stringent requirement of high quality crystal formation. Here we report bright room temperature phosphorescence by embedding a purely organic phosphor into an amorphous glassy polymer matrix. Our study implies that the reduced beta (β)-relaxation of isotactic PMMA most efficiently suppresses vibrational triplet decay and allows the embedded organic phosphors to achieve a bright 7.5% phosphorescence quantum yield. We also demonstrate a microfluidic device integrated with a novel temperature sensor based on the metal-free purely organic phosphors in the temperature-sensitive polymer matrix. This unique system has many advantages: (i) simple device structures without feeding additional temperature sensing agents, (ii) bright phosphorescence emission, (iii) a reversible thermal response, and (iv) tunable temperature sensing ranges by using different polymers.

  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.

  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. Tailored SERS substrates obtained with cathodic arc plasma ion implantation of gold nanoparticles into a polymer matrix.

    PubMed

    Ferreira, Jacqueline; Teixeira, Fernanda S; Zanatta, Antonio R; Salvadori, Maria C; Gordon, Reuven; Oliveira, Osvaldo N

    2012-02-14

    This manuscript reports on the fabrication of plasmonic substrates using cathodic arc plasma ion implantation, in addition to their performance as SERS substrates. The technique allows for the incorporation of a wide layer of metallic nanoparticles into a polymer matrix, such as PMMA. The ability to pattern different structures using the PMMA matrix is one of the main advantages of the fabrication method. This opens up new possibilities for obtaining tailored substrates with enhanced performance for SERS and other surface-enhanced spectroscopies, as well as for exploring the basic physics of patterned metal nanostructures. The architecture of the SERS-active substrate was varied using three adsorption strategies for incorporating a laser dye (rhodamine): alongside the nanoparticles into the polymer matrix, during the polymer cure and within nanoholes lithographed on the polymer. As a proof-of-concept, we obtained the SERS spectra of rhodamine for the three types of substrates. The hypothesis of incorporation of rhodamine molecules into the polymer matrix during the cathodic arc plasma ion implantation was supported by FDTD (Finite-Difference Time-Domain) simulations. In the case of arrays of nanoholes, rhodamine molecules could be adsorbed directly on the gold surface, then yielding a well-resolved SERS spectrum for a small amount of analyte owing to the short-range interactions and the large longitudinal field component inside the nanoholes. The results shown here demonstrate that the approach based on ion implantation can be adapted to produce reproducible tailored substrates for SERS and other surface-enhanced spectroscopies.

  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. 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.

  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.

    PubMed

    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 (epsilon<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 (3polymer 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. 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.

  7. Biotin-Functionalized Semiconducting Polymer in an Organic Field Effect Transistor and Application as a Biosensor

    PubMed Central

    Kim, Zin-Sig; Lim, Sang Chul; Kim, Seong Hyun; Yang, Yong Suk; Hwang, Do-Hoon

    2012-01-01

    This report presents biotin-functionalized semiconducting polymers that are based on fluorene and bithiophene co-polymers (F8T2). Also presented is the application of these polymers to an organic thin film transistor used as a biosensor. The side chains of fluorene were partially biotinylated after the esterification of the biotin with corresponding alcohol-groups at the side chain in F8T2. Their properties as an organic semiconductor were tested using an organic thin film transistor (OTFT) and were found to show typical p-type semiconductor curves. The functionality of this biosensor in the sensing of biologically active molecules such as avidin in comparison with bovine serum albumin (BSA) was established through a selective decrease in the conductivity of the transistor, as measured with a device that was developed by the authors. Changes to the optical properties of this polymer were also measured through the change in the color of the UV-fluorescence before and after a reaction with avidin or BSA. PMID:23112654

  8. Biotin-functionalized semiconducting polymer in an organic field effect transistor and application as a biosensor.

    PubMed

    Kim, Zin-Sig; Lim, Sang Chul; Kim, Seong Hyun; Yang, Yong Suk; Hwang, Do-Hoon

    2012-01-01

    This report presents biotin-functionalized semiconducting polymers that are based on fluorene and bithiophene co-polymers (F8T2). Also presented is the application of these polymers to an organic thin film transistor used as a biosensor. The side chains of fluorene were partially biotinylated after the esterification of the biotin with corresponding alcohol-groups at the side chain in F8T2. Their properties as an organic semiconductor were tested using an organic thin film transistor (OTFT) and were found to show typical p-type semiconductor curves. The functionality of this biosensor in the sensing of biologically active molecules such as avidin in comparison with bovine serum albumin (BSA) was established through a selective decrease in the conductivity of the transistor, as measured with a device that was developed by the authors. Changes to the optical properties of this polymer were also measured through the change in the color of the UV-fluorescence before and after a reaction with avidin or BSA.

  9. Effects Of Ion Energy On Nitrogen Plasma Immersion Ion Implantation In UHMWPE Polymer Through A Metal Grid

    SciTech Connect

    Ueda, M.; Oliveira, R. M.; Rossi, J. O.; Lepienski, C. M.; Vilela, W. A.

    2006-11-13

    Herein, we consider the potential application of plasma immersion ion implantation (PIII) for treatment of polymer surfaces. This paper presents some experimental data for ultra-high molecular weight polyethylene (UHMWPE) implanted with nitrogen using PIII process. This polymer is widely used in medical prosthesis and PIII treatment has revealed to be an ease and cheap way to improve the lifetime of prosthesis made with UHMWPE. Here we show the latest results for UHMWPE surface treatment obtained with the use of a high voltage pulser of 100kV/200A based on coaxial Blumlein technology.

  10. Effects Of Ion Energy On Nitrogen Plasma Immersion Ion Implantation In UHMWPE Polymer Through A Metal Grid

    NASA Astrophysics Data System (ADS)

    Ueda, M.; Oliveira, R. M.; Rossi, J. O.; Lepienski, C. M.; Vilela, W. A.

    2006-11-01

    Herein, we consider the potential application of plasma immersion ion implantation (PIII) for treatment of polymer surfaces. This paper presents some experimental data for ultra-high molecular weight polyethylene (UHMWPE) implanted with nitrogen using PIII process. This polymer is widely used in medical prosthesis and PIII treatment has revealed to be an ease and cheap way to improve the lifetime of prosthesis made with UHMWPE. Here we show the latest results for UHMWPE surface treatment obtained with the use of a high voltage pulser of 100kV/200A based on coaxial Blumlein technology.

  11. Characteristics of organic light-emitting diodes with conducting polymer anodes on plastic substrates

    NASA Astrophysics Data System (ADS)

    Huh, Jin Woo; Kim, Young Min; Park, Young Wook; Choi, Jin Hwan; Lee, Jin Woo; Lee, Jong Woo; Yang, Jae Woong; Ju, Sung Hoo; Paek, Kyeong Kap; Ju, Byeong Kwon

    2008-02-01

    The fabrication of conducting polymer films by a screen-printing method and characterization of an organic light-emitting diode (OLED) implemented using these films as an anode on plastic substrates are reported. Organic transparent electrode materials containing poly(3,4-ethylenedioxythiophene) (PEDOT) doped with poly(styrenesulfonic acid) (PSS) (PEDOT:PSS) were used after the modification by a unique nanoparticle binder design. The electro-optical properties as well as mechanical stabilities of these films were measured. The OLED performances when employing these films were comparable to that of OLEDs using indium tin oxide (ITO) despite their relatively poor conductivity. An external quantum efficiency of the OLED using this anode is ˜3.5%, which is about twice as that of OLEDs using ITO. These results show that the organic transparent electrode of a conducting polymer film patterned by the screen-printing method is a potential candidate for an electrode of the flexible OLED.

  12. Controlled self-organization of polymer nanopatterns over large areas.

    PubMed

    Eryilmaz, Ilknur Hatice; Mohanraj, John; Dal Zilio, Simone; Fraleoni-Morgera, Alessandro

    2017-09-05

    Self-assembly methods allow to obtain ordered patterns on surfaces with exquisite precision, but often lack in effectiveness over large areas. Here we report on the realization of hierarchically ordered polymethylmethacrylate (PMMA) nanofibres and nanodots over large areas from solution via a fast, easy and low-cost method named ASB-SANS, based on a ternary solution that is cast on the substrate. Simple changes to the ternary solution composition allow to control the transition from nanofibres to nanodots, via a wide range of intermediate topologies. The ternary solution includes the material to be patterned, a liquid solvent and a solid substance able to sublimate. The analysis of the fibres/dots width and inter-pattern distance variations with respect to the ratio between the solution components suggests that the macromolecular chains mobility in the solidified sublimating substance follows Zimm-like models (mobility of macromolecules in diluted liquid solutions). A qualitative explanation of the self-assembly phenomena originating the observed nanopatterns is given. Finally, ASB-SANS-generated PMMA nanodots arrays have been used as lithographic masks for a silicon substrate and submitted to Inductively Coupled Plasma-Reactive Ion Etching (ICP-RIE). As a result, nanopillars with remarkably high aspect ratios have been achieved over areas as large as several millimeters square, highlighting an interesting potential of ASB-SANS in practical applications like photon trapping in photovoltaic cells, surface-enhanced sensors, plasmonics.

  13. 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.

  14. Dynamics of Intracellular Polymers in Enhanced Biological Phosphorus Removal Processes under Different Organic Carbon Concentrations

    PubMed Central

    Xing, Lizhen; Ren, Li; Tang, Bo; 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. PMID:24381942

  15. Quantitative measurement of VUV radiation related to polymer pre-treatment in a microwave driven low pressure plasma

    NASA Astrophysics Data System (ADS)

    Mitschker, Felix; Iglesias, Enrique; Fiebrandt, Marcel; Bibinov, Nikita; Awakowicz, Peter; InstituteElectrical Engineering; Plasma Technology Team

    2016-09-01

    Plasma pre-treatment of polymers is used for a wide range of applications, e.g. prior to deposition of thin SiOx barrier films. At this, plasma generated particles and vacuum ultraviolet (VUV) radiation can reach the polymer surface. Both have a severe impact on the polymer interface, resulting in the production of e.g. dangling bonds. These modifications govern subsequent thin film growth. For understanding of pre-treatment processes, VUV radiation has to be quantified. Absolute VUV photon fluences are determined in situ, at the substrate holder, applying sodium salicylate (NaSal) as a scintillator. Therefore, VUV photons are quantified from 50 nm to 325 nm, due to constant quantum efficiency of NaSal, as integrals over defined wavelength ranges (50-110, 110-170, 170-200 and 200-325 nm). The set up allows for measurement with three scintillators. Each is equipped with optical filters. Observation of the fluorescence band is performed by means of optical fibers and a photomultiplier. Quantification is achieved by simultaneous measurement with an absolutely calibrated echelle spectrometer in the spectral range from 200 nm to 325 nm, taking into account observed plasma volumes. VUV photons are quantified for argon and oxygen plasmas as well as mixtures of both. Support by the German Research Foundation (DFG) within the framework of the SFB TRR 87/1 is acknowledged.

  16. Infrared gas phase study on plasma-polymer interactions in high-current diffuse dielectric barrier discharge

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Welzel, S.; Starostin, S. A.; van de Sanden, M. C. M.; Engeln, R.; de Vries, H. W.

    2017-06-01

    A roll-to-roll high-current diffuse dielectric barrier discharge at atmospheric pressure was operated in air and Ar/N2/O2 gas mixtures. The exhaust gas from the discharge was studied using a high-resolution Fourier-transform infrared spectrometer in the range from 3000 to 750 cm-1 to unravel the plasma-polymer interactions. The absorption features of HxNyOz, COx, and HCOOH (formic acid) were identified, and the relative densities were deduced by fitting the absorption bands of the detected molecules. Strong interactions between plasma and polymer (Polyethylene-2,6-naphthalate, or PEN) in precursor-free oxygen-containing gas mixtures were observed as evidenced by a high COx production. The presence of HCOOH in the gas effluent, formed through plasma-chemical synthesis of COx, turns out to be a sensitive indicator for etching. By adding tetraethylorthosilicate precursor in the plasma, dramatic changes in the COx production were measured, and two distinct deposition regimes were identified. At high precursor flows, a good agreement with the precursor combustion and the COx production was observed, whereas at low precursor flows an etching-deposition regime transpires, and the COx production is dominated by polymer etching.

  17. Plasma polymer coatings to aid retinal pigment epithelial growth for transplantation in the treatment of age related macular degeneration.

    PubMed

    Kearns, Victoria; Mistry, Anita; Mason, Sharon; Krishna, Yamini; Sheridan, Carl; Short, Robert; Williams, Rachel L

    2012-08-01

    Subretinal transplantation of functioning retinal pigment epithelial (RPE) cells grown on a synthetic substrate is a potential treatment for age-related macular degeneration (AMD), a common cause of irreversible vision loss in developed countries. Plasma polymers give the opportunity to tailor the surface chemistry of the artificial substrate whilst maintaining the bulk properties. In this study, plasma polymers with different functionalities were investigated in terms of their effect on RPE attachment and growth. Plasma polymers of acrylic acid (AC), allyl amine (AM) and allyl alcohol (AL) were fabricated and characterised using X-ray photoelectron spectroscopy (XPS) and water contact angle measurements. Octadiene (OD) hydrocarbon films and tissue culture polystyrene were used as controls. Wettability varied from hydrophobic OD to relatively hydrophilic AC. XPS demonstrated four very different surfaces with the expected functionalities. Attachment, proliferation and morphological examination of an RPE cell line and primary RPE cells were investigated. Both cell types grew on all surfaces, with the exception of OD, although the proliferation rate of primary cells was low. Good epithelial morphology was also demonstrated. Plasma polymerised films show potential as cell carrier surfaces for RPE cells in the treatment of AMD.

  18. 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.

  19. Interactive Thermal Effects on Metal-Organic Framework Polymer Composite Membranes.

    PubMed

    Cacho-Bailo, Fernando; Téllez, Carlos; Coronas, Joaquín

    2016-07-04

    Polymeric membranes are important tools for intensifying separation processes in chemical industries, concerning strategic tasks such as CO2 sequestration, H2 production, and water supply and disposal. Mixed-matrix and supported membranes have been widely developed; recently many of them have been based on metal-organic frameworks (MOFs). However, most of the impacts MOFs have within the polymer matrix have yet to be determined. The effects related to thermal behavior arising from the combination of MOF ZIF-8 and polysulfone have now been quantified. The catalyzed oxidation of the polymer is strongly affected by the MOF crystal size and distribution inside the membrane. A 16 wt % 140 nm-sized ZIF-8 loading causes a 40 % decrease in the observed activation energy of the polysulfone oxidation that takes place at a temperature (545 °C) 80 °C lower than in the raw polymer (625 °C).

  20. 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.

  1. 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.

  2. 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.

  3. Giant plasma membrane vesicles: models for understanding membrane organization.

    PubMed

    Levental, Kandice R; Levental, Ilya

    2015-01-01

    The organization of eukaryotic membranes into functional domains continues to fascinate and puzzle cell biologists and biophysicists. The lipid raft hypothesis proposes that collective lipid interactions compartmentalize the membrane into coexisting liquid domains that are central to membrane physiology. This hypothesis has proven controversial because such structures cannot be directly visualized in live cells by light microscopy. The recent observations of liquid-liquid phase separation in biological membranes are an important validation of the raft hypothesis and enable application of the experimental toolbox of membrane physics to a biologically complex phase-separated membrane. This review addresses the role of giant plasma membrane vesicles (GPMVs) in refining the raft hypothesis and expands on the application of GPMVs as an experimental model to answer some of key outstanding problems in membrane biology. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Simple O2 plasma-processed V2O5 as an anode buffer layer for high-performance polymer solar cells.

    PubMed

    Bao, Xichang; Zhu, Qianqian; Wang, Ting; Guo, Jing; Yang, Chunpeng; Yu, Donghong; Wang, Ning; Chen, Weichao; Yang, Renqiang

    2015-04-15

    A simple O2 plasma processing method for preparation of a vanadium oxide (V2O5) anode buffer layer on indium tin oxide (ITO)-coated glass for polymer solar cells (PSCs) is reported. The V2O5 layer with high transmittance and good electrical and interfacial properties was prepared by spin coating a vanadium(V) triisopropoxide oxide alcohol solution on ITO and then O2 plasma treatment for 10 min [V2O5 (O2 plasma)]. PSCs based on P3HT:PC61BM and PBDTTT-C:PC71BM using V2O5 (O2 plasma) as an anode buffer layer show high power conversion efficiencies (PCEs) of 4.47 and 7.54%, respectively, under the illumination of AM 1.5G (100 mW/cm(2)). Compared to that of the control device with PBDTTT-C:PC71BM as the active layer and PSS (PCE of 6.52%) and thermally annealed V2O5 (PCE of 6.27%) as the anode buffer layer, the PCE was improved by 15.6 and 20.2%, respectively, after the introduction of a V2O5 (O2 plasma) anode buffer layer. The improved PCE is ascribed to the greatly improved fill factor and enhanced short-circuit current density of the devices, which benefited from the change in the work function of V2O5, a surface with many dangling bonds for better interfacial contact, and the excellent charge transport property of the V2O5 (O2 plasma) layer. The results indicate that an O2 plasma-processed V2O5 film is an efficient and economical anode buffer layer for high-performance PSCs. It also provides an attractive choice for low-cost fabrication of organic electronics.

  5. Biodegradable inorganic-organic hybrids of methacrylate star polymers for bone regeneration.

    PubMed

    Chung, Justin J; Fujita, Yuki; Li, Siwei; Stevens, Molly M; Kasuga, Toshihiro; Georgiou, Theoni K; Jones, Julian R

    2017-03-08

    Hybrids that are molecular scale co-networks of organic and inorganic components are promising biomaterials, improving the brittleness of bioactive glass and the strength of polymers. Methacrylate polymers have high potential as the organic source for hybrids since they can be produced, through controlled polymerization, with sophisticated polymer architectures that can bond to silicate networks. Previous studies showed the mechanical properties of hybrids can be modified by polymer architecture and molar mass (MM). However, biodegradability is critical if hybrids are to be used as tissue engineering scaffolds, since the templates must be remodelled by host tissue. Degradation by-products have to either completely biodegrade or be excreted by the kidneys. Enzyme, or bio-degradation is preferred to hydrolysis by water uptake as it is expected to give a more controlled degradation rate. Here, branched and star shaped poly(methyl methacrylate-co-3-(trimethoxysilyl)propyl methacrylate) (poly(MMA-co-TMSPMA)) were synthesized with disulphide based dimethacrylate (DSDMA) as a biodegradable branching agent. Biodegradability was confirmed by exposing the copolymers to glutathione, a tripeptide which is known to cleave disulphide bonds. Cleaved parts of the star polymer from the hybrid system were detected after 2weeks of immersion in glutathione solution, and MM was under threshold of kidney filtration. The presence of the branching agent did not reduce the mechanical properties of the hybrids and bone progenitor cells attached on the hybrids in vitro. Incorporation of the DSDMA branching agent has opened more possibilities to design biodegradable methacrylate polymer based hybrids for regenerative medicine.

  6. Solvent Molding of Organic Morphologies Made of Supramolecular Chiral Polymers.

    PubMed

    Đorđević, Luka; Marangoni, Tomas; Miletić, Tanja; Rubio-Magnieto, Jenifer; Mohanraj, John; Amenitsch, Heinz; Pasini, Dario; Liaros, Nikos; Couris, Stelios; Armaroli, Nicola; Surin, Mathieu; Bonifazi, Davide

    2015-07-01

    The self-assembly and self-organization behavior of uracil-conjugated enantiopure (R)- or (S)-1,1'-binaphthyl-2,2'-diol (BINOL) and a hydrophobic oligo(p-phenylene ethynylene) (OPE) chromophore exposing 2,6-di(acetylamino)pyridine termini are reported. Systematic spectroscopic (UV-vis, CD, fluorescence, NMR, and SAXS) and microscopic studies (TEM and AFM) showed that BINOL and OPE compounds undergo triple H-bonding recognition, generating different organic nanostructures in solution. Depending on the solvophobic properties of the liquid media (toluene, CHCl3, CHCl3/CHX, and CHX/THF), spherical, rod-like, fibrous, and helical morphologies were obtained, with the latter being the only nanostructures expressing chirality at the microscopic level. SAXS analysis combined with molecular modeling simulations showed that the helical superstructures are composed of dimeric double-cable tape-like structures that, in turn, are supercoiled at the microscale. This behavior is interpreted as a consequence of an interplay among the degree of association of the H-bonded recognition, the vapor pressure of the solvent, and the solvophobic/solvophilic character of the supramolecular adducts in the different solutions under static and dynamic conditions, namely solvent evaporation conditions at room temperature.

  7. Self-Organizing Cyclolinear Organosilicon Polymers in Bulk and on the Surface of Water †

    PubMed Central

    Makarova, Nataliya N.; Astapova, Tat’yana V.; Buzin, Alexander I.; Polishchuk, Arkady P.; Chizhova, Nataliya V.; Petrova, Irina M.

    2013-01-01

    Cyclolinear organocarbosiloxane polymers with varying content and location of (CH2)n groups in the monomer unit were synthesized by reactions of heterofunctional polycondensation and polyaddition of difunctional organocyclosiloxanes and organocyclocarbosiloxanes. Their bulk properties were studied by differential scanning calorimetry and X-ray structural analysis. It was shown that on introduction of CH2 groups into the methylcyclohexasiloxane unit, the polymer retains the ability to self-organize with formation of a mesomorphic state in a wide temperature range, while on introduction of (CH2)2 fragments in a cyclotetrasiloxane unit or in a bridge connecting two methylcyclotetra(hexa)siloxane units it does not. Comparison of the X-ray data of dihydroxy derivatives of decamethylcyclohexasiloxane and decamethyl-5-carbocyclohexasiloxane with packing of cyclolinear organosilicon polymers in bulk shows that the polymer inherits the layered type of crystalline structure typical for monomers. Langmuir films of cyclolinear polymethylcarbosiloxanes with different design of monomer units were studied as well. It was revealed that all polymers form monomolecular films at the air/water interface, excluding those having longer hydrophobic fragment than hydrophilic ones. The ability to form multilayers depends on the surroundings of Si atom in the bridge between the cycles. PMID:24013373

  8. Conformation study of helical main-group polymers: Organic and inorganic, trans and gauche

    SciTech Connect

    Cui, C.X.; Kertesz, M. )

    1989-06-07

    In this paper electronic structures of some helical polymers, which range from typical organic polymers such as polyethylene and poly(oxymethylene) to standard inorganic polymers such as polymeric sulfur to main-group (P, B, etc.) atomic chains in crystals (such as NaP, CrB, etc.), have been investigated by means of our helical modifications of solid-state band theory programs based on modified neglect of diatomic overlap (MNDO) and extended Hueckel theory (EHT). The analysis of orbital interactions shows that the all-trans conformation for the polymer with either less or more than six valence electrons in the repeat unit is energetically favorable as compared with the gauche conformation while the polymers having valence electrons close to six in the repeat unit are more likely to be found in a gauche conformation, except for polyethylene and polysilane, for which both conformations are stable. The stability of all-trans-polyethylene and -polysilane is attributed to the weak repulsions between C-H and Si-H bonding electron pairs. A quadratic relationship between band width and the corresponding closed-shell repulsion for an energy band is established.

  9. Tin-based inorganic-organic hybrid polymers for high energy-density applications

    NASA Astrophysics Data System (ADS)

    Tran, Huan; Kuma, Arun; Pilania, Ghanshyam; Ramprasad, Rampi

    2014-03-01

    In one of our recent works[1], an organotin polymer was synthesized and suggested to be promising polymeric dielectric, simultaneously exhibiting a high dielectric constant ɛ and a high band gap Eg. Motivated by this result, we study a family of inorganic-organic hybrid polymers based on -(SnF2) x-(CH2) y - as the repeating structural unit (x = 2 , y = 4 , 8 , and 12). The stable structures of these hybrid polymers, predicted by the minima-hopping method, are studied by first-principles calculations at the level of density functional theory. Our calculations show that these polymers are wide band gap materials (up to 6.07 eV). In addition, their dielectric constants are between 4.6 and 7.8, well above that of polypropylene (ɛ ~= 2 . 2), the standard dielectric material for high energy-density capacitors. Therefore, we suggest that the hybrid polymers based on -(SnF2) x-(CH2) y - are promising candidates for high energy-density applications. Our work is supported by the Office of Naval Research through the Multidisciplinary University Research Initiative (MURI).

  10. Self-organizing cyclolinear organosilicon polymers in bulk and on the surface of water.

    PubMed

    Makarova, Nataliya N; Astapova, Tat'yana V; Buzin, Alexander I; Polishchuk, Arkady P; Chizhova, Nataliya V; Petrova, Irina M

    2013-09-05

    Cyclolinear organocarbosiloxane polymers with varying content and location of (CH2)n groups in the monomer unit were synthesized by reactions of heterofunctional polycondensation and polyaddition of difunctional organocyclosiloxanes and organocyclocarbosiloxanes. Their bulk properties were studied by differential scanning calorimetry and X-ray structural analysis. It was shown that on introduction of CH2 groups into the methylcyclohexasiloxane unit, the polymer retains the ability to self-organize with formation of a mesomorphic state in a wide temperature range, while on introduction of (CH2)2 fragments in a cyclotetrasiloxane unit or in a bridge connecting two methylcyclotetra(hexa)siloxane units it does not. Comparison of the X-ray data of dihydroxy derivatives of decamethylcyclohexasiloxane and decamethyl-5-carbocyclohexasiloxane with packing of cyclolinear organosilicon polymers in bulk shows that the polymer inherits the layered type of crystalline structure typical for monomers. Langmuir films of cyclolinear polymethylcarbosiloxanes with different design of monomer units were studied as well. It was revealed that all polymers form monomolecular films at the air/water interface, excluding those having longer hydrophobic fragment than hydrophilic ones. The ability to form multilayers depends on the surroundings of Si atom in the bridge between the cycles.

  11. A novel strategy to immobilize bacteria on polymer particles for efficient adsorption and biodegradation of soluble organics.

    PubMed

    Cai, Yahui; Yang, Shun; Chen, Dongyun; Li, Najun; Xu, Qingfeng; Li, Hua; He, Jinghui; Lu, Jianmei

    2017-08-17

    A novel strategy was used to immobilize bacterial cells on the surface of functional polymer particles for the efficient adsorption and biodegradation of organics in wastewater. First, the bacterial cells were aggregated using a vinyl-containing pre-polymer, and the obtained bacteria-pre-polymer complex was then used as a particle stabilizer to construct a stable Pickering emulsion of functional cross-linking monomers and hydrophobic superparamagnetic iron oxide nanoparticles (the oil phase) in water. After polymerization, the bacteria-pre-polymer complex was covalently fixed to the surface of the polymer particles. Two species of bacterial cells (Pseudomonas putida andParacoccus denitrificans) were used as models to study their removal capacity for phenol and DMF, respectively. Batch experiments showed that the as-prepared magnetic bacteria-polymer (MPB) composites could efficiently remove organics from the aqueous solutions, and the encapsulated iron oxide nanoparticles enabled the MPB composites to be magnetically separated.

  12. 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.

  13. 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.

  14. A Multi-Objective Optimization Technique to Model the Pareto Front of Organic Dielectric Polymers

    NASA Astrophysics Data System (ADS)

    Gubernatis, J. E.; Mannodi-Kanakkithodi, A.; Ramprasad, R.; Pilania, G.; Lookman, T.

    Multi-objective optimization is an area of decision making that is concerned with mathematical optimization problems involving more than one objective simultaneously. Here we describe two new Monte Carlo methods for this type of optimization in the context of their application to the problem of designing polymers with more desirable dielectric and optical properties. We present results of applying these Monte Carlo methods to a two-objective problem (maximizing the total static band dielectric constant and energy gap) and a three objective problem (maximizing the ionic and electronic contributions to the static band dielectric constant and energy gap) of a 6-block organic polymer. Our objective functions were constructed from high throughput DFT calculations of 4-block polymers, following the method of Sharma et al., Nature Communications 5, 4845 (2014) and Mannodi-Kanakkithodi et al., Scientific Reports, submitted. Our high throughput and Monte Carlo methods of analysis extend to general N-block organic polymers. This work was supported in part by the LDRD DR program of the Los Alamos National Laboratory and in part by a Multidisciplinary University Research Initiative (MURI) Grant from the Office of Naval Research.

  15. 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.

  16. One-hundred-nm-scale electronic structure and transport calculations of organic polymers on the K computer

    NASA Astrophysics Data System (ADS)

    Imachi, Hiroto; Yokoyama, Seiya; Kaji, Takami; Abe, Yukiya; Tada, Tomofumi; Hoshi, Takeo

    2016-12-01

    One-hundred-nm-scale electronic structure calculations were carried out on the K supercomputer by our original simulation code ELSES (http://www.elses.jp/) The present paper reports preliminary results of transport calculations for condensed organic polymers. Large-scale calculations are realized by novel massively parallel order-N algorithms. The transport calculations were carried out as a theoretical extension for the quantum wavepacket dynamics simulation. The method was applied to a single polymer chain and condensed polymers.

  17. 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.

  18. 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.

  19. Aqueous Processing for Printed Organic Electronics: Conjugated Polymers with Multistage Cleavable Side Chains

    PubMed Central

    2017-01-01

    The ability to process conjugated polymers via aqueous solution is highly advantageous for reducing the costs and environmental hazards of large scale roll-to-roll processing of organic electronics. However, maintaining competitive electronic properties while achieving aqueous solubility is difficult for several reasons: (1) Materials with polar functional groups that provide aqueous solubility can be difficult to purify and characterize, (2) many traditional coupling and polymerization reactions cannot be performed in aqueous solution, and (3) ionic groups, though useful for obtaining aqueous solubility, can lead to a loss of solid-state order, as well as a screening of any applied bias. As an alternative, we report a multistage cleavable side chain method that combines desirable aqueous processing attributes without sacrificing semiconducting capabilities. Through the attachment of cleavable side chains, conjugated polymers have for the first time been synthesized, characterized, and purified in organic solvents, converted to a water-soluble form for aqueous processing, and brought through a final treatment to cleave the polymer side chains and leave behind the desired electronic material as a solvent-resistant film. Specifically, we demonstrate an organic soluble polythiophene that is converted to an aqueous soluble polyelectrolyte via hydrolysis. After blade coating from an aqueous solution, UV irradiation is used to cleave the polymer’s side chains, resulting in a solvent-resistant, electroactive polymer thin film. In application, this process results in aqueous printed materials with utility for solid-state charge transport in organic field effect transistors (OFETs), along with red to colorless electrochromism in ionic media for color changing displays, demonstrating its potential as a universal method for aqueous printing in organic electronics. PMID:28979937

  20. Nanospace-Mediated Self-Organization of Nanoparticles in Flexible Porous Polymer Templates.

    PubMed

    Kuroda, Yoshiyuki; Muto, Itaru; Shimojima, Atsushi; Wada, Hiroaki; Kuroda, Kazuyuki

    2017-08-31

    Self-organization is a fundamental process for the construction of complex hierarchically ordered nanostructures, which are widespread in biological systems. However, precise control of size, shape, and surface properties is required for self-organization of nanoparticles. Here, we demonstrate a novel self-organization phenomenon mediated by flexible nanospaces in templates. Inorganic nanoparticles (e.g., silica, zirconia, and titania) are deposited in porous polymer thin films with randomly distributed pores on the surface, leaving a partially filled nanospace in each pore. Heating at temperatures beyond the glass transition temperature of the template leads to self-organization of the inorganic nanoparticles into one-dimensional chainlike networks. The self-organization is mediated by the deformation and fusion of the residual nanospaces, and it can be rationally controlled by sequential heat treatments. These results show that a nanospace, defined by the nonexistence of matter, interacts indirectly with matter and can be used as a component of self-organization systems.

  1. Design of Donor Polymers with Strong Temperature-Dependent Aggregation Property for Efficient Organic Photovoltaics.

    PubMed

    Hu, Huawei; Chow, Philip C Y; Zhang, Guangye; Ma, Tingxuan; Liu, Jing; Yang, Guofang; Yan, He

    2017-09-15

    Bulk heterojunction (BHJ) organic solar cells (OSCs) have attracted intensive research attention over the past two decades owing to their unique advantages including mechanical flexibility, light weight, large area, and low-cost fabrications. To date, OSC devices have achieved power conversion efficiencies (PCEs) exceeding 12%. Much of the progress was enabled by the development of high-performance donor polymers with favorable morphological, electronic, and optical properties. A key problem in morphology control of OSCs is the trade-off between achieving small domain size and high polymer crystallinity, which is especially important for the realization of efficient thick-film devices with high fill factors. For example, the thickness of OSC blends containing state-of-the-art PTB7 family donor polymers are restricted to ∼100 nm due to their relatively low hole mobility and impure polymer domains. To further improve the device performance and promote commercialization of OSCs, there is a strong demand for the design of new donor polymers that can achieve an optimal blend morphology containing highly crystalline yet reasonably small domains. In this Account, we highlight recent progress on a new family of conjugated polymers with strong temperature-dependent aggregation (TDA) property. These polymers are mostly disaggregated and can be easily dissolved in solution at high temperatures, yet they can strongly aggregate when the solution is cooled to room temperature. This unique aggregation property allows us to control the disorder-order transition of the polymer during solution processing. By preheating the solution to high temperature (∼100 °C), the polymer chains are mostly disaggregated before spin coating; as the temperature of the solution drops during the spin coating process, the polymer can strongly aggregate and form crystalline domains yet that are not excessivelylarge. The overall blend morphology can be optimized by various processing conditions (e

  2. 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

  3. 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.

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

    PubMed

    Kasálková, Nikola Slepičková; Slepička, Petr; Kolská, Zdeňka; Hodačová, Petra; Kučková, Stěpánka; Svorčík, Václav

    2014-04-04

    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.

  5. Low-concentration polymers inhibit and accelerate crystal growth in organic glasses in correlation with segmental mobility.

    PubMed

    Powell, C Travis; Cai, Ting; Hasebe, Mariko; Gunn, Erica M; Gao, Ping; Zhang, Geoff; Gong, Yuchuan; Yu, Lian

    2013-09-05

    Crystal growth in organic glasses has been studied in the presence of low-concentration polymers. Doping the organic glass nifedipine (NIF) with 1 wt % polymer has no measurable effect on the glass transition temperature Tg of host molecules, but substantially alters the rate of crystal growth, from a 10-fold reduction to a 30% increase at 12 °C below the host Tg. Among the polymers tested, all but polyethylene oxide (PEO) inhibit growth. The inhibitory effects greatly diminish in the liquid state (at Tg + 38 °C), but PEO persists to speed crystal growth. The crystal growth rate varies exponentially with polymer concentration, in analogy with the polymer effect on solvent mobility, though the effect on crystal growth can be much stronger. The ability to inhibit crystal growth is not well ordered by the strength of host-polymer hydrogen bonds, but correlates remarkably well with the neat polymer's Tg, suggesting that the mobility of polymer chains is an important factor in inhibiting crystal growth in organic glasses. The polymer dopants also affect crystal growth at the free surface of NIF glasses, but the effect is attenuated according to the power law us ∝ ub(0.35), where us and ub are the surface and bulk growth rates.

  6. 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.

  7. Nanoparticle-Directed Metal-Organic Framework/Porous Organic Polymer Monolithic Supports for Flow-Based Applications.

    PubMed

    Darder, María Del Mar; Salehinia, Shima; Parra, José B; Herrero-Martinez, José M; Svec, Frantisek; Cerdà, Víctor; Turnes Palomino, Gemma; Maya, Fernando

    2017-01-18

    A two-step nanoparticle-directed route for the preparation of macroporous polymer monoliths for which the pore surface is covered with a metal-organic framework (MOF) coating has been developed to facilitate the use of MOFs in flow-based applications. The flow-through monolithic matrix was prepared in a column format from a polymerization mixture containing ZnO-nanoparticles. These nanoparticles embedded in the precursor monolith were converted to MOF coatings via the dissolution-precipitation equilibrium after filling the pores of the monolith with a solution of the organic linker. Pore surface coverage with the microporous zeolitic imidazolate framework ZIF-8 resulted in an increase in surface area from 72 to 273 m(2) g(-1). Monolithic polymer containing ZIF-8 coating was implemented as a microreactor catalyzing the Knoevenagel condensation reaction and also in extraction column format enabling the preconcentration of trace levels of toxic chlorophenols in environmental waters. Our approach can be readily adapted to other polymers and MOFs thus enabling development of systems for flow-based MOF applications.

  8. Conductive Polymer Synthesis with Single-Crystallinity via a Novel Plasma Polymerization Technique for Gas Sensor Applications

    PubMed Central

    Park, Choon-Sang; Kim, Dong Ha; Shin, Bhum Jae; Kim, Do Yeob; Lee, Hyung-Kun; Tae, Heung-Sik

    2016-01-01

    This study proposes a new nanostructured conductive polymer synthesis method that can grow the single-crystalline high-density plasma-polymerized nanoparticle structures by enhancing the sufficient nucleation and fragmentation of the pyrrole monomer using a novel atmospheric pressure plasma jet (APPJ) technique. Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and field emission scanning electron microscopy (FE-SEM) results show that the plasma-polymerized pyrrole (pPPy) nanoparticles have a fast deposition rate of 0.93 µm·min−1 under a room-temperature process and have single-crystalline characteristics with porous properties. In addition, the single-crystalline high-density pPPy nanoparticle structures were successfully synthesized on the glass, plastic, and interdigitated gas sensor electrode substrates using a novel plasma polymerization technique at room temperature. To check the suitability of the active layer for the fabrication of electrochemical toxic gas sensors, the resistance variations of the pPPy nanoparticles grown on the interdigitated gas sensor electrodes were examined by doping with iodine. As a result, the proposed APPJ device could obtain the high-density and ultra-fast single-crystalline pPPy thin films for various gas sensor applications. This work will contribute to the design of highly sensitive gas sensors adopting the novel plasma-polymerized conductive polymer as new active layer. PMID:28773932

  9. Conductive Polymer Synthesis with Single-Crystallinity via a Novel Plasma Polymerization Technique for Gas Sensor Applications.

    PubMed

    Park, Choon-Sang; Kim, Dong Ha; Shin, Bhum Jae; Kim, Do Yeob; Lee, Hyung-Kun; Tae, Heung-Sik

    2016-09-30

    This study proposes a new nanostructured conductive polymer synthesis method that can grow the single-crystalline high-density plasma-polymerized nanoparticle structures by enhancing the sufficient nucleation and fragmentation of the pyrrole monomer using a novel atmospheric pressure plasma jet (APPJ) technique. Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and field emission scanning electron microscopy (FE-SEM) results show that the plasma-polymerized pyrrole (pPPy) nanoparticles have a fast deposition rate of 0.93 µm·min(-1) under a room-temperature process and have single-crystalline characteristics with porous properties. In addition, the single-crystalline high-density pPPy nanoparticle structures were successfully synthesized on the glass, plastic, and interdigitated gas sensor electrode substrates using a novel plasma polymerization technique at room temperature. To check the suitability of the active layer for the fabrication of electrochemical toxic gas sensors, the resistance variations of the pPPy nanoparticles grown on the interdigitated gas sensor electrodes were examined by doping with iodine. As a result, the proposed APPJ device could obtain the high-density and ultra-fast single-crystalline pPPy thin films for various gas sensor applications. This work will contribute to the design of highly sensitive gas sensors adopting the novel plasma-polymerized conductive polymer as new active layer.

  10. 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.

  11. 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.

  12. Electrophoretic and aggregation behavior of bovine, horse and human red blood cells in plasma and in polymer solutions.

    PubMed

    Bäumler, H; Neu, B; Mitlöhner, R; Georgieva, R; Meiselman, H J; Kiesewetter, H

    2001-01-01

    The electrophoretic mobility of native and glutaraldehyde-fixed bovine, human, and horse red blood cells (RBC) was investigated as a function of ionic strength (5-150 mM) and concentration of 464 kDa dextran (2 and 3 g/dl); RBC aggregation in autologous plasma and in dextran solutions was also measured. In agreement with previous observations, human and horse RBC form stable rouleaux whereas bovine RBC do not aggregate in either plasma or in dextran 464 kDa solutions. Electrophoretic measurements showed a species-dependent adsorption and depletion of dextran that can be theoretically evaluated. Adsorption of polymer is not a prerequisite for RBC aggregation (bovine RBC show the highest amount of adsorbed dextran yet do not aggregate). Aggregate formation thus occurs as long as the Gibbs free energy difference, given by the osmotic pressure difference between the bulk phase and the polymer-depleted region between two RBC, is larger than the steric and electrostatic repulsive energy contributed by the macromolecules present on the RBC surface. With increasing bulk-phase polymer concentration the depletion layer thickness decreases and the amount of adsorbed macromolecules increases, thereby resulting in an increase of the repulsive component of the interaction energy and decreased aggregation. We thus view electrophoretic measurements of RBC in various media as an important tool for understanding polymer behavior near the red cell surface and hence the mechanisms involved in RBC aggregation.

  13. Exploring the Effects of Argon Plasma Treatment on Plasmon Frequency and the Chemiresistive Properties of Polymer-Carbon Nanotube Metacomposite

    PubMed Central

    Rivera, Manuel; Rahaman, Mostafizur; Velázquez, Rafael; Zhou, Andrew F.; Feng, Peter X.

    2017-01-01

    Metacomposites, composite materials exhibiting negative permittivity, represent an opportunity to create materials with depressed plasmon frequency without the need to create complex structural geometries. Although many reports exist on the synthesis and characterizations of metacomposites, very few have ventured into exploring possible applications that could take advantage of the unique electrical properties of these materials. In this article, we report on the chemiresistive properties of a polymer-CNT metacomposite and explore how these are affected by Argon plasma treatment. PMID:28837097

  14. Exploring the Effects of Argon Plasma Treatment on Plasmon Frequency and the Chemiresistive Properties of Polymer-Carbon Nanotube Metacomposite.

    PubMed

    Rivera, Manuel; Rahaman, Mostafizur; Aldalbahi, Ali; Velázquez, Rafael; Zhou, Andrew F; Feng, Peter X

    2017-08-24

    Metacomposites, composite materials exhibiting negative permittivity, represent an opportunity to create materials with depressed plasmon frequency without the need to create complex structural geometries. Although many reports exist on the synthesis and characterizations of metacomposites, very few have ventured into exploring possible applications that could take advantage of the unique electrical properties of these materials. In this article, we report on the chemiresistive properties of a polymer-CNT metacomposite and explore how these are affected by Argon plasma treatment.

  15. 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.

  16. Theoretical study of the dark-oxidation reaction mechanisms for organic polymers

    NASA Astrophysics Data System (ADS)

    Wang, Guixiu; Zhu, Rongxiu; Zhang, Dongju; Liu, Chengbu

    2006-08-01

    To model the dark-oxidation mechanism of organic polymers, the reactions of the corresponding model compounds, including cumene, methyl 2-methylbutyrate, methyl methacrylate and methylacrylic acid, with triplet O 2 molecule, have been studied by performing density functional theory calculations at the UB3LYP/6-31G(d) level. The calculated results show that these model compounds can be oxygenated by O 2 via an H-abstract mechanism. The structures of initial contact charge transfer complexes, transition states, intermediates of cage-like pairs of radicals, and final hydro-peroxides involved in the reactions have been shown in details. The present results are expected to provide a general guidance for understanding the dark-oxidation mechanism of organic polymers.

  17. Hyperbranched polymers and dendrimers as templates for organic/inorganic hybrid nanomaterials.

    PubMed

    Huang, Xinhua; Zheng, Sudan; Kim, Il

    2014-02-01

    This paper reviews the recent research and development of hyperbranched polymers (HPs) and dendrimers, and their use as templates for organic-inorganic hybrid nanomaterials. Hyperbranched polymers (HPs) are highly branched macromolecules with three-dimensional globular structures featuring unique properties such as low viscosity, high solubility, and a large number of terminal functional groups compared to their linear analogs. They are easily prepared by (1) condensation polymerization, (2) self-condensing vinyl copolymerization (SCVCP), and (3) ring-opening multibranch polymerization methods. Organic-inorganic hybrid nanomaterials are synthesized by a template approach using HPs/dendrimers. Monometallic, bimetallic (alloy and core/shell), semiconductor, and metal oxide nanoparticles have been prepared by this route. The dendrimer component of these composites serves not only as a template for preparing the nanoparticles but also as a stabilizer for the nanoparticles.

  18. 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.

  19. Chromium functionalized diglyme plasma polymer coating enhances enzyme-linked immunosorbent assay performance.

    PubMed

    Welch, Nicholas G; Madiona, Robert M T; Easton, Christopher D; Scoble, Judith A; Jones, Robert T; Muir, Benjamin W; Pigram, Paul J

    2016-11-10

    Ensuring the optimum orientation, conformation, and density of substrate-bound antibodies is critical for the success of sandwich enzyme-linked immunosorbent assays (ELISAs). In this work, the authors utilize a diethylene glycol dimethyl ether plasma polymer (DGpp) coating, functionalized with chromium within a 96 well plate for the enhanced immobilization of a capture antibody. For an equivalent amount of bound antibody, a tenfold improvement in the ELISA signal intensity is obtained on the DGpp after incubation with chromium, indicative of improved orientation on this surface. Time-of-flight secondary-ion-mass-spectrometry (ToF-SIMS) and principal component analysis were used to probe the molecular species at the surface and showed ion fragments related to lysine, methionine, histidine, and arginine coupled to chromium indicating candidate antibody binding sites. A combined x-ray photoelectron spectroscopy and ToF-SIMS analysis provided a surface molecular characterization that demonstrates antibody binding via the chromium complex. The DGpp+Cr surface treatment holds great promise for improving the efficacy of ELISAs.

  20. A novel core-shell molecularly imprinted polymer based on metal-organic frameworks as a matrix.

    PubMed

    Qian, Kun; Fang, Guozhen; Wang, Shuo

    2011-09-28

    A novel core-shell molecularly imprinted polymer is firstly prepared by coating the MIP shell onto the surface of the metal-organic framework, which shows a homogeneous polymer film, cubic shape, thermal stability, and exhibits a higher specific surface area and a faster transfer-mass speed compared with that of the bulk MIP.

  1. Colloidal crystallization of colloidal silica grafted with iron(0) complex-tethered polymers in organic solvents

    NASA Astrophysics Data System (ADS)

    Yoshinaga, Kohji; Mouri, Emiko

    2007-09-01

    Incorporation of iron(0) complex into polymer-grafted silica and colloidal crystallization in organic solvent were studied. In this study, zero-valence iron complex, vinylferrocene (Vfc) and iron(0)tricarbonyl(4,4-dimethyl-1,-4-cyclohexadienyl) acrylate (Fe(0)Ac) or methacrylate (Fe(0)Me), were introduced into grafted polymer to prevent from increasing ionic strength in colloidal crystallization system. Poly(methyl methacrylate (MMA)-co-Vfc)-grafted silica never formed colloidal crystals in polar solvent, such as acetone or acetonitrile. However, increasing ferrocenyl group fraction in the polymer resulted in disturbing the crystallization. Poly(N-isopropylacrylamide (NIPAAm)-co-Vfc)-grafted silica, which was composed of mole fraction of Vfc, 1/3, afforded crystallization in ethanol over the particle fraction of 0.053. In the case of diene-Fe(0)(CO) 3/polymer-grafted silica, poly(MMA-co-Fe(0)Ac)-, poly(NIPAAm-co-Fe(0)Ac)- and poly(N.N-dimethylacrylamide (DMAAm)-co-Fe(0)Ac)-grafted silica gave colloidal crystallization in relatively low polar solvents, DMF, acetone, acetonirile and ethanol, critical volume fraction for which were in the range from 0.054 to 0.117. In the case of copolymer-grafted silica containing Fe(0)Me, poly(MMA-co-FeMe)-grafted silica crystallized in DMF, Interestingly, especially in cases of polymer-grafted silica containing Fe(0)Ac or Fe(0)Me composed of the highest mole fraction Fe(0)Me, 1/2, afforded crystallization in DMF. The iridescence color of the colloidal crystals was changed with the combination of grafted polymer and solvent. The characteristic coloration of the solution from reddish to greenish color is possibly due to absorption of blue light region by diene-Fe(0)(CO) 3 complex and Bragg deflection on colloidal crystals.

  2. Toward intrinsically stretchable organic semiconductors: mechanical properties of high-performance conjugated polymers

    NASA Astrophysics Data System (ADS)

    Sawyer, Eric J.; Savagatrup, Suchol; O'Connor, Timothy F.; Makaram, Aditya S.; Burke, Daniel J.; Zaretski, Aliaksandr V.; Printz, Adam D.; Lipomi, Darren J.

    2014-10-01

    This paper describes several approaches to understanding and improving the response of π-conjugated (semiconducting) polymers to tensile strain. Our principal goal was to establish the design criteria for introducing elasticity and ductility in conjugated (semiconducting) polymers through a rigorous analysis of the structural determinants of the mechanical properties of this type of material. We elucidated the details of the effect of the alkyl side chain length on the mechanical properties of regioregular polythiophene and used this analysis to select materials for stretching and transfer printing of organic solar cells to hemispherical substrates. This demonstration represents the first time that a conjugated polymer device has ever been stretched and conformally bonded to a complex 3D surface (i.e., other than a cone or cylinder, for which flexibility—as opposed to stretchability—is sufficient). We then further explored the details of the dependence of the mechanical properties on the side chain of a semiconducting polymer by synthesizing a series of hybrid materials (block and random copolymers) containing both short and long side chains. This analysis revealed the unusual semiconducting polymer, poly(3-heptylthiophene), as having an excellent combination of mechanical and electronic properties. In parallel, we explored a new method of producing "blocky" copolymers using a new procedure based on random segmentation of conjugated monomers. We found that introduction of structural randomness increased the elasticity without having detrimental effects on the photovoltaic performance. We also describe methods of synthesizing large volumes of conjugated polymers in environmentally benign ways that were amenable to manufacturing.

  3. Platinum-acetylide polymers with higher dimensionality for organic solar cells.

    PubMed

    Wang, Qiwei; He, Zhicai; Wild, Andreas; Wu, Hongbin; Cao, Yong; S Schubert, Ulrich; Chui, Chung-Hin; Wong, Wai-Yeung

    2011-07-04

    A new series of platinum(II)-acetylide polymers P1-P3 containing thiophene-triarylamine chromophores of different dimensions were synthesized and their electronic band structures, field-effect charge transport, and application in bulk heterojunction solar cells were evaluated. These materials are soluble in polar organic solvents and show strong absorptions in the solar spectra (with the highest absorption coefficient of 1.59×10(5)  cm(-1) from thin films), thus rendering them excellent candidates for bulk heterojunction polymer solar cells. The spin-coated polymer thin films showed p-channel field-effect charge transport with hole mobilities of 1.90×10(-5) to 7.86×10(-5)  cm(2)  V(-1)  s(-1) for P1-P3 and an improved charge carrier transport was found for P2 with higher molecular dimensionality than P1. The dependence of their photovoltaic properties and dimensionality was also investigated. Even if the polymers possess relatively high bandgaps and narrow absorption bandwidths, the highest power conversion efficiency of 2.24 % can be obtained based on blends of P3 with [6,6]phenyl-C(61)-butyric acid methyl ester (PCBM) (1:5, w/w) under AM1.5 simulated solar illumination. The present work indicates that multidimensional polymers exhibit a better photovoltaic performance over the linear polymers under the same measurement conditions and can provide an attractive approach to developing highly efficient conjugated metallopolymers for efficient power generation.

  4. Selective sensing of volatile organic compounds using novel conducting polymer-metal nanoparticle hybrids

    NASA Astrophysics Data System (ADS)

    Vaddiraju, Sreeram; Gleason, Karen K.

    2010-03-01

    Conducting polymer-metal nanoparticle hybrids, fabricated by assembling metal nanoparticles on top of functionalized conducting polymer film surfaces using conjugated linker molecules, enable the selective sensing of volatile organic compounds (VOCs). In these conducting polymer-metal nanoparticle hybrids, selectivity is achieved by assembling different metals on the same conducting polymer film. This eliminates the need to develop either different polymers chemistries or device configurations for each specific analyte. In the hybrids, chemisorption of the analyte vapor induces charge redistribution in the metal nanoparticles and changes their work function. The conjugated linker molecule causes this change in the work function of the tethered nanoparticles to affect the electronic states in the underlying conducting polymer film. The result is an easily measurable change in the resistance of the hybrid structure. The fabrication of these sensing elements involved the covalent assembly of nickel (Ni) and palladium (Pd) metal nanoparticles on top of poly(3,4-ethylenedioxythiophene-co-thiophene-3-acetic acid), poly(EDOT-co-TAA), films using 4-aminothiophenol linker molecules. The change in resistance of hybrid Pd/poly(EDOT-co-TAA) and Ni/poly(EDOT-co-TAA) hybrid films to acetone and toluene, respectively, is observed to be in proportion to their concentrations. The projected detection limits are 2 and 10 ppm for toluene and acetone, respectively. A negligible response (resistance change) of the Pd/poly(EDOT-co-TAA) films to toluene exposure confirmed its selectivity for detecting acetone. Similarly, lack of response to acetone confirmed the selectivity of the Ni/poly(EDOT-co-TAA) stacks for detecting toluene. It is anticipated that the assembly of other metals such as Ag, Au and Cu on top of poly(EDOT-co-TAA) would provide selectivity for detecting and discriminating other VOCs.

  5. Understanding the Device Physics in Polymer-Based Ionic-Organic Ratchets.

    PubMed

    Hu, Yuanyuan; Brus, Viktor; Cao, Wei; Liao, Kenneth; Phan, Hung; Wang, Ming; Banerjee, Kaustav; Bazan, Guillermo C; Nguyen, Thuc-Quyen

    2017-02-07

    High-performance solution-processed ionic-organic ratchets are fabricated using polymer semiconductors. The devices can provide both high short-circuit current and open-circuit voltage at room temperature, and be driven by AC signals with frequencies up to 13.56 MHz. The effects of trap density, mobility, and rectification ratio in the device on short-circuit current are investigated and clarified.

  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. Bacterial behaviors on polymer surfaces with organic and inorganic antimicrobial compounds.

    PubMed

    Ji, Junhui; Zhang, Wei

    2009-02-01

    Infection of medical polymers is often caused by bacterial adherence and bio-film formation, and it is one of the major clinical complications causing a high rate of mortality and morbidity. In this study, it was investigated that differences of organic and inorganic antimicrobial reagents incorporated into polymers for bacterial adherence and bio-film formation. Our experimental results show adhesion of bacteria and bio-film (gram positive Staphylococcus aureus and gram negative Escherichia coli) are evidently reduced by adding organic antimicrobial reagents into PVC. However, inorganic antimicrobial reagents can not make much difference in bacterial bio-film formation on their polymers' surface. Although the surface containing inorganic antimicrobial reagents has excellent ability in killing bacteria, the amount of Escherichia coli on samples surface is no less than that on the control sample during bacterial adhesion due to both various hydrophilicity and different antibacterial mechanisms on the surface. Furthermore, bacterial bio-film formation on various hydrophilic samples is investigated, and it is observed that organic and inorganic antimicrobial compounds have much different effect on surface hydrophilicity. As a result, hydrophilicity becomes a major factor for bacterial adhesion and bio-film.

  8. 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.

  9. Mixing plasmonic Au nanoparticles into all polymer layers for improving the efficiency of organic solar cells

    NASA Astrophysics Data System (ADS)

    Choy, Wallace C. H.; Wang, Charlie C. D.; Fung, Dixon D. S.; Sha, Wei E. I.; Xie, Feng-Xian

    2012-09-01

    To enhance the light trapping of organic solar cells (OSCs), metallic (e.g. Au, Ag) nanoparticles (NPs) have been incorporated into the polymer layers conveniently in solution process. Although power conversion efficiency (PCE) of OSCs has been shown to improve by incorporating metallic NPs in either the buffer layer such as poly-(3,4-ethylenedioxythiophene) :poly(styrenesulfonate) (PEDOT:PSS)[1] or the active layer[2], the understanding on the changes is still not quite clear. Moreover, there are very limited studies on incorporating metallic NPs in more than one organic layer and investigating their effects on the optical and electrical properties as well as the performances of OSCs. In this work, monofunctional poly(ethylene glycol) (PEG)-capped Au NPs of sizes 18 nm and 35 nm are doped in the PEDOT:PSS and poly(3-hexylthiophene) (P3HT): phenyl-C61-butyric acid methyl ester (PCBM) layers respectively, leading to an improvement of PCE by ~22% compared to the optimized control device. We will firstly identify the impact of NPs in each polymer layer on OSC characteristics by doping Au NPs in either the PEDOT:PSS or P3HT:PCBM layer. Then, we will investigate Au NPs incorporated in all polymer layers. We demonstrate that the accumulated benefits of incorporating Au NPs in all organic layers of OSCs can achieve larger improvements in OSC performances.

  10. Progress Report for Activities of the U. S. Burning Plasma Organization

    SciTech Connect

    Van Dam, James W

    2009-04-07

    This report describes the activities of the past year of the U. S. Burning Plasma Organization (USBPO), a national organization of scientists involved in researching the properties of magnetically confined burning fusion plasmas. Its main activities are the coordination, facilitation, and promotion of research activities in the U. S. fusion energy sciences program relevant to burning plasma science and, specifically, of preparations for U. S. participation in the international ITER experiment. Specifically, the USBPO mission is to advance the scientific understanding of burning plasmas and to ensure the greatest benefit from a burning plasma experiment by coordinating relevant U. S. fusion research with broad community participation.

  11. 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.

  12. Shrink wrapping redox-active crystals of polyoxometalate open frameworks with organic polymers via crystal induced polymerisation.

    PubMed

    Takashima, Yohei; Miras, Haralampos N; Glatzel, Stefan; Cronin, Leroy

    2016-06-14

    We report examples of crystal surface modification of polyoxometalate open frameworks whereby the use of pyrrole or aniline as monomers leads to the formation of the corresponding polymers via an oxidative polymerization process initiated by the redox active POM scaffolds. Guest-exchange experiments demonstrate that the polymers can finely tune the guest exchange rate and their structural integrity is retained after the surface modifications. In addition, the formation of polyoxometalate-based self-fabricating tubes by the dissolution of Keggin-based network crystals were also modulated by the polymers, allowing a new type of hybrid inorganic polymer with an organic coating to be fabricated.

  13. Structure Analyses of Organic Thin Films Prepared by a Plasma Enhanced Vacuum Evaporation

    NASA Astrophysics Data System (ADS)

    Sugimoto, Ryousuke; Osada, Kousuke; Kurata, Masahiko; Matsumoto, Hiroyuki; Iwamori, Satoru; Noda, Kazutoshi

    Organic thin films were prepared with pyromellitic dianhydride (PMDA) and oxydianiline (ODA) by vacuum evaporation with or without argon plasma, and molecular structures and surface morphologies of the PMDA, ODA, polyamic acid (PAA) and polyimide (PI) thin films were analyzed. The surface roughness decreased due to the plasma during the deposition. Oxygen content of the PMDA thin film prepared with the plasma decreased compared to that without the plasma. However, the PMDA thin film prepared with the plasma had a hydrophilic surface compared to that without the plasma. All of these organic thin films prepared with the plasma had hydrophilic surfaces compared to those without the plasma. Surface roughness of these thin films has a smaller effect on the wettability than hydrophilic moieties.

  14. Minimum free-energy paths for the self-organization of polymer brushes.

    PubMed

    Gleria, Ignacio; Mocskos, Esteban; Tagliazucchi, Mario

    2017-03-22

    A methodology to calculate minimum free-energy paths based on the combination of a molecular theory and the improved string method is introduced and applied to study the self-organization of polymer brushes under poor solvent conditions. Polymer brushes in a poor solvent cannot undergo macroscopic phase separation due to the physical constraint imposed by the grafting points; therefore, they microphase separate forming aggregates. Under some conditions, the theory predicts that the homogeneous brush and the aggregates can exist as two different minima of the free energy. The theoretical methodology introduced in this work allows us to predict the minimum free-energy path connecting these two minima as well as the morphology of the system along the path. It is shown that the transition between the homogeneous brush and the aggregates may involve a free-energy barrier or be barrierless depending on the relative stability of the two morphologies and the chain length and grafting density of the polymer. In the case where a free-energy barrier exists, one of the morphologies is a metastable structure and, therefore, the properties of the brush as the quality of the solvent is cycled are expected to display hysteresis. The theory is also applied to study the adhesion/deadhesion transition between two opposing surfaces modified by identical polymer brushes and it is shown that this process may also require surpassing a free-energy barrier.

  15. Sol-gel-processed inorganic oxides: organic polymer composites for second-order nonlinear optical applications

    NASA Astrophysics Data System (ADS)

    Zieba, Jaroslaw W.; Zhang, Yue; Prasad, Paras N.; Casstevens, Martin K.; Burzynski, Ryszard

    1992-12-01

    A new class of promising composite materials consisting of sol-gel processed inorganic oxides and organic polymers has been developed over the last several years. These materials have been shown to be homogeneous, mechanically stable and have excellent optical properties. Second-order nonlinear optical properties are dependent upon the active chromophore being aligned within the structure. We report here the studies on the second-order nonlinear optical properties of a new oxide:polymer composite. A second-order chromophore, (N,N- diethylamino-((Beta) )-nitrostyrene or DEANST) has been doped into a sol-gel/polymer composite comprised of polyvinylpyrrolidone (PVP) and silica. The removal of solvent from a simple sol-gel preparation causes a tremendous shrinkage of the pores of the matrix. In addition, this particular polymer is capable of being crosslinked at elevated temperatures. These two effects were used to retain the alignment of the chromophores within this unique host material. The second-harmonic generation technique was used as a function of time to ascertain the utility of this approach and to determine the precise roles of processing conditions and components necessary to bring about this effect. The results of this work indicate that this composite can preserve the alignment of DEANST to satisfactory levels, making it an excellent candidate for device applications.

  16. ZnO nanorod arrays for various low-bandgap polymers in inverted organic solar cells.

    PubMed

    Ho, Ping-Yi; Thiyagu, Subramani; Kao, Shao-Hsuan; Kao, Chia-Yu; Lin, Ching-Fuh

    2014-01-07

    Due to the limited diffusion length of carriers in polymer solar cells (PSCs), the path of carriers is a crucial factor that determines the device performance. Zinc oxide nanorods (NRs) as the electron transport channel can reduce electron-hole recombination and transport the electron to the electrode efficiently for poly(3-hexylthiophene) (P3HT), but have been seldom demonstrated for low-bandgap polymers. Here we successfully applied ZnO NRs, which were grown via the hydrothermal method, as a platform to enhance PSC efficiency for various low-bandgap polymers. In order to assure that the nanorod morphology functioned properly for PSCs, the growth time, the concentration, and the resulting morphology were systematically investigated in depths. Such ZnO NRs were applied to different organic systems, resulting in the increase of the PCE for PBDTTT-C/PC71BM from 4.76% to 6.07% and PBDTTT-C-T/PC71BM from 5.40% to 7.34%. Through those experiments, we established a potentially universal and efficient ZnO NRs platform for various low-bandgap polymers to achieve high efficiency of inverted PSCs.

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

    PubMed Central

    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. 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.

  19. Pave Thermal Highway with Self-Organized Nanocrystals in Transparent Polymer Composites.

    PubMed

    Mu, Liwen; Ji, Tuo; Chen, Long; Mehra, Nitin; Shi, Yijun; Zhu, Jiahua

    2016-10-03

    Phonon transfer is greatly scattered in traditional polymer composites due to the unpaired phonon frequency at polymer/filler interface. A key innovation of this work is to build continuous crystal network by self-organization and utilize it as "thermal highway" that circumvents the long-existing interfacial thermal barrier issue in traditional composites. By tuning the molecular diffusion rate of dicarboxylic acids (oxalic acid, malonic acid and succinic acid), different crystal structures including skeletal, dendrite, diffusion limited aggregates and spherulite were synthesized in PVA film. These continuous crystal structures benefit the efficient phonon transfer in the composites with minimized interfacial scattering and lead to a significant thermal conductivity enhancement by up to 180% compared to pure polymer. Moreover, the transparent feature of these composite films provides additional benefits in display applications. Post heat treatment effect on the thermal conductivity of the composite films shows a time dependent behavior. These uniquely structured polymer/crystal composites are expected to generate significant impacts in thermal management applications.

  20. 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

  1. Plasma glutamine deficiency is associated with multiple organ failure in critically ill children.

    PubMed

    Ekmark, Leif; Rooyackers, Olav; Wernerman, Jan; Fläring, Urban

    2015-03-01

    A low plasma glutamine concentration (<420 µmol/L) is an independent risk factor for mortality in critically ill adult patients. Glutamine metabolism in children is less well characterized. However, pediatric ICU (PICU) mortality is low and, therefore, mortality is difficult to use as an endpoint. Here we evaluated if plasma glutamine concentration at admission to the PICU, relates to the development of multiple organ failure, using pediatric logistic organ dysfunction score (PELOD)-score. In this observational study, consecutive critically ill children (n = 149) admitted to the PICU of a tertiary university hospital as well as a reference group of healthy children (n = 60) were included. Plasma glutamine concentration and the PELOD were determined at admission for all patients and at day 5 for those patients still in the PICU. Plasma glutamine concentration at admission was low in the PICU patients as compared to controls (p = 0.00002) and patients with a low plasma glutamine concentration had more organ failure as compared to patients with higher plasma glutamine concentration (p = 0.0001). Plasma glutamine concentration normalized in patients staying >5 days in the PICU. Plasma glutamine depletion was present in 40 % of patients at PICU admission and it was associated with the development of multiple organ failure. Furthermore, the majority of the critically ill children normalized their plasma glutamine concentration within 5 days, which is different from adult ICU patients. The study suggests that an initial plasma glutamine deficiency is associated with multiple organ failure in critically ill children.

  2. Static ToF-SIMS analysis of plasma chemically deposited ethylene/allyl alcohol co-polymer films

    NASA Astrophysics Data System (ADS)

    Oran, U.; Swaraj, S.; Friedrich, J. F.; Unger, W. E. S.

    2006-07-01

    A plasma co-polymerization of ethylene as a "chain extending" monomer and allyl alcohol as a carrier monomer for hydroxyl groups was studied. The composition of the feed gas was systematically varied and the plasma co-polymers were analyzed in terms of their relative concentrations of OH functional groups by static Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) immediately after their preparation without any air contact, i.e., under so called "in situ" conditions. The relative OH group concentration involved in the -CH 2-OH groups was derived from the normalized yields of the CH 3O + secondary fragment ion. The density of functional groups in the plasma co-polymers was found to vary non-linearly with respect to the mole percentage of the monomers in the feed gas. Co-polymerization phenomena, i.e. chemical interactions and recombination reactions taking place between monomer molecules in the plasma and/or during the deposition process, become evident in ToF-SIMS spectra.

  3. Self-organization in a driven dissipative plasma system

    NASA Astrophysics Data System (ADS)

    Shaikh, Dastgeer; Dasgupta, B.; Hu, Q.; Zank, G. P.

    2010-02-01

    We perform a fully self-consistent three-dimensional numerical simulation for a compressible, dissipative magnetoplasma driven by large-scale perturbations, that contain a fairly broad spectrum of characteristic modes, ranging from largest scales to intermediate scales and down to the smallest scales, where the energy of the system is dissipated by collisional (ohmic) and viscous dissipations. Additionally, our simulation includes nonlinear interactions amongst a wide range of fluctuations that are initialized with random spectral amplitudes, leading to the cascade of spectral energy in the inertial range spectrum, and takes into account large-scale as well as small-scale perturbations that may have been induced by the background plasma fluctuations, as well as the non-adiabatic exchange of energy leading to the migration of energy from the energy-containing modes or randomly injected energy driven by perturbations and further dissipated by the smaller scales. Besides demonstrating the comparative decays of the total energy and the dissipation rate of the energy, our results show the existence of a perpendicular component of the current, thus clearly confirming that the self-organized state is non-force free.

  4. Dehydrocoupling and Silazane Cleavage Routes to Organic-Inorganic Hybrid Polymers with NBN Units in the Main Chain.

    PubMed

    Lorenz, Thomas; Lik, Artur; Plamper, Felix A; Helten, Holger

    2016-06-13

    Despite the great potential of both π-conjugated organoboron polymers and BN-doped polycyclic aromatic hydrocarbons in organic optoelectronics, our knowledge of conjugated polymers with B-N bonds in their main chain is currently scarce. Herein, the first examples of a new class of organic-inorganic hybrid polymers are presented, which consist of alternating NBN and para-phenylene units. Polycondensation with B-N bond formation provides facile access to soluble materials under mild conditions. The photophysical data for the polymer and molecular model systems of different chain lengths reveal a low extent of π-conjugation across the NBN units, which is supported by DFT calculations. The applicability of the new polymers as macromolecular polyligands is demonstrated by a cross-linking reaction with Zr(IV) .

  5. Computational design of an enantioselective molecular imprinted polymer for the solid phase extraction of S-warfarin from plasma.

    PubMed

    Ahmadi, F; Yawari, E; Nikbakht, M

    2014-04-18

    An enantioselective molecular imprinted polymer for S-warfarin was designed computationally by using the density functional theory (DFT) at B3LYP/631G+ (d, p) level and Gaussian 2003 package. The effect of polymerization solvent was also evaluated by the polarizable continuum model (PCM) and it was based on the measurement of interaction energies (ΔE) between S-warfarin and monomers in different polymerization solvents. The computational method showed that the methacrylic acid (MAA) and acetonitrile (AN) had the highest stabilization energy for the pre-polymerization adducts. Additionally, the mole ratio of 1:3 give the highest ΔE, therefore, the polymer was synthesized by the thermal bulk polymerization method with the mole ratio of S-warfarin-(MAA)3. The enantioselective extraction of MIP for R and S-warfarin was evaluated by chiral separation chromatography and polarimetry methods. The results revealed that the proposed S-warfarin molecular imprinted polymer has a moderate recognition for extraction of R-warfarin in a racemic mixture and had no recognition for other foreign drugs. In a racemic mixture of R and S-warfarin, the polymer is able to remove about 20% of R-warfarin. The linearity between responses (peak areas) and concentrations of S-warfarin in plasma sample was found in the range of 15.4-3080ngmL(-1) (R(2)=0.999).The linear range for a racemic mixture of R, S-warfarin in plasma which has been obtained by RP-C18-HPLC-UV method, was 12.0-2500ngmL(-1) (R(2)=0.998). The polymer was used for analysis of a real sample and as expected the accurate results were obtained.

  6. Highly Sensitive Flexible NH3 Sensors Based on Printed Organic Transistors with Fluorinated Conjugated Polymers.

    PubMed

    Nketia-Yawson, Benjamin; Jung, A-Ra; Noh, Yohan; Ryu, Gi-Seong; Tabi, Grace Dansoa; Lee, Kyung-Koo; Kim, BongSoo; Noh, Yong-Young

    2017-03-01

    Understanding the sensing mechanism in organic chemical sensors is essential for improving the sensing performance such as detection limit, sensitivity, and other response/recovery time, selectivity, and reversibility for real applications. Here, we report a highly sensitive printed ammonia (NH3) gas sensor based on organic thin film transistors (OTFTs) with fluorinated difluorobenzothiadiazole-dithienosilole polymer (PDFDT). These sensors detected NH3 down to 1 ppm with high sensitivity (up to 56%) using bar-coated ultrathin (<4 nm) PDFDT layers without using any receptor additives. The sensing mechanism was confirmed by cyclic voltammetry, hydrogen/fluorine nuclear magnetic resonance, and UV/visible absorption spectroscopy. PDFDT-NH3 interactions comprise hydrogen bonds and electrostatic interactions between the PDFDT polymer backbone and NH3 gas molecules, thus lowering the highest occupied molecular orbital levels, leading to hole trapping in the OTFT sensors. Additionally, density functional theory calculations show that gaseous NH3 molecules are captured via cooperation of fluorine atoms and dithienosilole units in PDFDT. We verified that incorporation of functional groups that interact with a specific gas molecule in a conjugated polymer is a promising strategy for producing high-performance printed OTFT gas sensors.

  7. Temperature and composition-dependent density of states in organic small-molecule/polymer blend transistors

    NASA Astrophysics Data System (ADS)

    Hunter, Simon; Mottram, Alexander D.; Anthopoulos, Thomas D.

    2016-07-01

    The density of trap states (DOS) in organic p-type transistors based on the small-molecule 2,8-difluoro-5,11-bis(triethylsilylethynyl) anthradithiophene (diF-TES ADT), the polymer poly(triarylamine) and blends thereof are investigated. The DOS in these devices are measured as a function of semiconductor composition and operating temperature. We show that increasing operating temperature causes a broadening of the DOS below 250 K. Characteristic trap depths of ˜15 meV are measured at 100 K, increasing to between 20 and 50 meV at room-temperature, dependent on the semiconductor composition. Semiconductor films with high concentrations of diF-TES ADT exhibit both a greater density of trap states as well as broader DOS distributions when measured at room-temperature. These results shed light on the underlying charge transport mechanisms in organic blend semiconductors and the apparent freezing-out of hole conduction through the polymer and mixed polymer/small molecule phases at temperatures below 225 K.

  8. A General Model of Sensitized Luminescence in Lanthanide-Based Coordination Polymers and Metal-Organic Framework Materials.

    PubMed

    Einkauf, Jeffrey D; Clark, Jessica M; Paulive, Alec; Tanner, Garrett P; de Lill, Daniel T

    2017-05-15

    Luminescent lanthanides containing coordination polymers and metal-organic frameworks hold great potential in many applications due to their distinctive spectroscopic properties. While the ability to design coordination polymers for specific functions is often mentioned as a major benefit bestowed on these compounds, the lack of a meaningful understanding of the luminescence in lanthanide coordination polymers remains a significant challenge toward functional design. Currently, the study of these compounds is based on the antenna effect as derived from molecular systems, where organic antennae are used to facilitate lanthanide-centered luminescence. This molecular-based approach does not take into account the unique features of extended network solids, particularly the formation of band structure. While guidelines for the antenna effect are well established, they require modification before being applied to coordination polymers. A series of nine coordination polymers with varying topologies and organic linkers were studied to investigate the accuracy of the antenna effect in coordination polymer systems. By comparing a molecular-based approach to a band-based one, it was determined that the band structure that occurs in aggregated organic solids needs to be considered when evaluating the luminescence of lanthanide coordination polymers.

  9. 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.

  10. Studies of the influence of nonequilibrium plasma thermal exposure on the characteristics of the capillary-porous polymer material

    NASA Astrophysics Data System (ADS)

    Makhotkina, L. Yu; Khristoliubova, V. I.

    2017-01-01

    Capillary-porous materials, which include natural macromolecular tanning material, are exposed to a number of factors during the treatment by a nonequilibrium plasma. Plasma particles exchange the charge and energy with the atoms of the material during the interaction of the plasma with the surface. The results of treatment are desorption of atoms and molecules from the body surface, sputtering and evaporation of material’s particles, changes of the structure and phase state. In real terms during the modification of solids by nonequilibrium low-temperature plasma thermal effect influences the process. The energy supplied from the discharge during the process with low pressure, which is converted into heat, is significantly less than during the atmospheric pressure, but the thermal stability of high-molecular compounds used in the manufacture of materials and products of the tanning industry, is very limited and depends on the duration of the effect of temperature. Even short heating of hydrophilic polymers (proteins) (100-180 °C) causes a change in their properties. It decreases the collagen ability to absorb water vapor, to swell in water, acids, alkalis, and thus decreases their durability. Prolonged heating leads to a deterioration of the physical and mechanical properties. Higher heating temperatures it leads to the polymer degradation. The natural leather temperature during plasma exposure does not rise to a temperature of collagen degradation and does not result in changes of physical phase of the dermis. However, the thermal plasma exposure must be considered, since the high temperatures influence on physical and mechanical properties.

  11. Polymer-based stimuli-responsive recyclable catalytic systems for organic synthesis.

    PubMed

    Zhang, Jingli; Zhang, Mingxi; Tang, Kangjian; Verpoort, Francis; Sun, Taolei

    2014-01-15

    The introduction of stimuli-responsive polymers into the study of organic catalysis leads to the generation of a new kind of polymer-based stimuli-responsive recyclable catalytic system. Owing to their reversible switching properties in response to external stimuli, these systems are capable of improving the mass transports of reactants/products in aqueous solution, modulating the chemical reaction rates, and switching the catalytic process on and off. Furthermore, their stimuli-responsive properties facilitate the separation and recovery of the active catalysts from the reaction mixtures. As a fascinating approach of the controllable catalysis, these stimuli-responsive catalytic systems including thermoresponsive, pH-responsive, chemo-mechano-chemical, ionic strength-responsive, and dual-responsive, are reviewed in terms of their nanoreactors and mechanisms. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Impact of scaling to the resistive switching effect in organic polymer - based structures

    NASA Astrophysics Data System (ADS)

    Kotova, M. S.; Dronov, M. A.; Rzhevskiy, A. V.; Amitonov, S. V.; Dubinina, T. V.; Pushkarev, V. E.; Ryabova, L. I.; Khokhlov, D. R.

    2016-12-01

    The resistive switching effect has been studied in a set of organic polymer - based structures of a different composition and size scale from macro to micro. It is shown that scaling down reduces both the threshold switching voltage Vth and the respective effective electric field Eth. Furthermore, introduction of metal micro particles into a macro scale polymer matrix provides the same effect. Therefore the metal particle incorporation may be regarded as an alternative method of effective scaling, depending on an application. Switching speed of less than 15 ns, threshold voltage Vth (2 - 25) V, 105 cycle endurance, no significant moisture dependence and high retention time 3.5 months for scaled down samples aswell as for metal doped macro samples have been demonstrated. These characteristics are suitable for constructing memory devices. The switching effect mechanisms are discussed.

  13. Low Temperature Transient Performance of Polymer Organic Light-Emitting Diodes

    NASA Astrophysics Data System (ADS)

    Burnett, Karl

    2009-11-01

    Polymer Organic Light-Emitting Diodes (p-OLEDs) are conjugated polymers that conduct electric charges, enabling their use as semiconductors. Typical applications for p-OLEDs include high-resolution, high-efficiency displays, and when printed onto plastic substrates, thin and flexible patterned light sources such as vehicle dashboard displays and telephone keypads. We are investigating turn-on and turn-off transient effects in p-OLEDs that vary with temperature and the electrical driver. We have found that the turn-on transient is thermally activated, that light output is immediately proportional to current flow into the device, and that light emission continues from the device even after bias is removed. When these phenomena are fully characterized, they may explain transient effects seen in previous work, help describe the activation energies and rate kinetics in the device, and broaden the range of environments in which p-OLED devices may be used.

  14. 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.

  15. 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.

  16. Methodologies for Controlled Conjugated Polymer Synthesis and Characterization of Small Molecule Organic Semiconductors

    NASA Astrophysics Data System (ADS)

    Bakus, Ronald C., II

    Conjugated polymers can broadly be described as materials which have a structure composed of repeating monomeric units that show extended electronic communication along the backbone. The extended pi-conjugated nature of these materials gives them a set of unique electronic and optical properties, and has lead to their application in a multitude of various technologies. Of specific interest is the application of these materials in various organic electronics applications, such as solution processed plastic solar cells, light emitting diodes, and field effect transistors. Herein is described the synthesis of a class of well-defined, highly active organometallic initiators for use in controlled polymer synthesis. The polymers prepared using the nickel based initiators in Grignard metathesis polymerization posses the following characteristics: rapid generation of high molecular weight polymers, low polydispersity, linear relation between monomer conversion and molecular weight growth, and the selective transfer of an initiating moiety from the organometallic initiator to one polymer chain end. This initiator was then used to prepare a new class of biosensor materials wherein the polymer had a well defined biosensing end group. Additionally, a series of small molecule donors have been developed that have shown promise in a wide variety of organic electronic applications. These materials can broadly be described as having a D'ADAD' type structure where D, D', and A correspond to electron rich and electron deficient aromatic heterocycles, respectively. By tuning the identity of these groups and the side-chains attached to them, one can subtly influence the optical, electronic, and physical properties of the materials. These materials were investigated via single crystal x-ray diffraction studies to gain insight into how changes to the molecule structure such as heteroatom regioisomerism and isoelectronic substitutions effected the molecular structure. These changes in

  17. Polymer triplet energy levels need not limit photocurrent collection in organic solar cells.

    PubMed

    Schlenker, Cody W; Chen, Kung-Shih; Yip, Hin-Lap; Li, Chang-Zhi; Bradshaw, Liam R; Ochsenbein, Stefan T; Ding, Feizhi; Li, Xiaosong S; Gamelin, Daniel R; Jen, Alex K-Y; Ginger, David S

    2012-12-05

    We study charge recombination via triplet excited states in donor/acceptor organic solar cells and find that, contrary to intuition, high internal quantum efficiency (IQE) can be obtained in polymer/fullerene blend devices even when the polymer triplet state is significantly lower in energy than the intermolecular charge transfer (CT) state. Our model donor system comprises the copolymer PIDT-PhanQ: poly(indacenodithiophene-co-phenanthro[9,10-b]quinoxaline), which when blended with phenyl-C(71)-butyric acid methyl ester (PC(71)BM) is capable of achieving power conversion efficiencies of 6.0% and IQE ≈ 90%, despite the fact that the polymer triplet state lies 300 meV below the interfacial CT state. However, as we push the open circuit voltage (V(OC)) higher by tailoring the fullerene reduction potential, we observe signatures of a new recombination loss process near V(OC) = 1.0 V that we do not observe for PCBM-based devices. Using photoinduced absorption and photoluminescence spectroscopy, we show that a new recombination path opens via the fullerene triplet manifold as the energy of the lowest CT state approaches the energy of the fullerene triplet. This pathway appears active even in cases where direct recombination via the polymer triplet remains thermodynamically accessible. These results suggest that kinetics, as opposed to thermodynamics, can dominate recombination via triplet excitons in these blends and that optimization of charge separation and kinetic suppression of charge recombination may be fruitful paths for the next generation of panchromatic organic solar cell materials with high V(OC) and J(SC).

  18. Nano-organized collagen layers obtained by adsorption on phase-separated polymer thin films.

    PubMed

    Zuyderhoff, Emilienne M; Dupont-Gillain, Christine C

    2012-01-31

    The organization of adsorbed type I collagen layers was examined on a series of polystyrene (PS)/poly(methyl methacrylate) (PMMA) heterogeneous surfaces obtained by phase separation in thin films. These thin films were prepared by spin coating from solutions in either dioxane or toluene of PS and PMMA in different proportions. Their morphology was unraveled combining the information coming from X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and water contact angle measurements. Substrates with PMMA inclusions in a PS matrix and, conversely, substrates with PS inclusions in a PMMA matrix were prepared, the inclusions being either under the form of pits or islands, with diameters in the submicrometer range. The organization of collagen layers obtained by adsorption on these surfaces was then investigated. On pure PMMA, the layer was quite smooth with assemblies of a few collagen molecules, while bigger assemblies were found on pure PS. On the heterogeneous surfaces, it appeared clearly that the diameter and length of collagen assemblies was modulated by the size and surface coverage of the PS domains. If the PS domains, either surrounding or surrounded by the PMMA phase, were above 600 nm wide, a heterogeneous distribution of collagen was found, in agreement with observations made on pure polymers. Otherwise, fibrils could be formed, that were longer compared to those observed on pure polymers. Additionally, the surface nitrogen content determined by XPS, which is linked to the protein adsorbed amount, increased roughly linearly with the PS surface fraction, whatever the size of PS domains, suggesting that adsorbed collagen amount on heterogeneous PS/PMMA surfaces is a combination of that observed on the pure polymers. This work thus shows that PS/PMMA surface heterogeneities can govern collagen organization. This opens the way to a better control of collagen supramolecular organization at interfaces, which could in turn allow cell

  19. 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.

  20. From polymer to small organic molecules: a tight relationship between radical chemistry and solid-phase organic synthesis.

    PubMed

    Mirizzi, Danilo; Pulici, Maurizio

    2011-04-18

    Since Gomberg's discovery of radicals as chemical entities, the interest around them has increased through the years. Nowadays, radical chemistry is used in the synthesis of 75% of all polymers, inevitably establishing a close relationship with Solid-Phase Organic Synthesis. More recently, the interest of organic chemists has shifted towards the application of usual "in-solution" radical chemistry to the solid-phase, ranging from the use of supported reagents for radical reactions, to the development of methodologies for the synthesis of small molecules or potential libraries. The aim of this review is to put in perspective radical chemistry, moving it away from its origin as a synthetic means for solid supports, to becoming a useful tool for the synthesis of small molecules.

  1. Molecularly imprinted polymers based on SBA-15 for selective solid-phase extraction of baicalein from plasma samples.

    PubMed

    He, Hongliang; Gu, Xiaoli; Shi, Liying; Hong, Junli; Zhang, Hongjuan; Gao, Yankun; Du, Shuhu; Chen, Lina

    2015-01-01

    Highly selective molecularly imprinted mesoporous silica polymer (SBA-15@MIP) for baicalein (BAI) extraction was synthesized using a surface molecular imprinting technique on the SBA-15 supporter. Computational simulation was used to predict the optimal functional monomer for the rational design of SBA-15@MIP. Meanwhile, high adsorption capacity was obtained when a suitable yield of molecularly imprinted polymers (MIPs) layer was grafted onto the surface of SBA-15. Characterization and performance tests of the obtained polymer revealed that SBA-15@MIP possessed a highly ordered mesoporous structure, reached saturated adsorption within 60 min, and exhibited higher sorption capacity to the target molecule BAI compared with non-imprinted mesoporous silica polymer (SBA-15@NIP) and SBA-15. Finally, SBA-15@MIP was successfully applied to solid-phase extraction (SPE) coupled with high-performance liquid chromatography and ultraviolet detection (HPLC-UV) for the determination of trace BAI in plasma samples. Mean recoveries of BAI through the molecularly imprinted solid-phase extraction (MISPE) sorbent, non-imprinted solid-phase extraction (NISPE) sorbent, and SBA-15 solid-phase extraction (SBA-15-SPE) sorbent were 94.4, 22.7, and 10.7 %, respectively, and the relative standard deviations were 2.9, 2.6, and 3.6 %, respectively. These results reveal that SBA-15@MIP as a SPE sorbent has good applicability to selectively separate and enrich trace BAI from complex samples.

  2. Persistent organic pollutants in plasma of delivering women from Arkhangelsk.

    PubMed

    Sandanger, Torkjel M; Odland, Jon Øyvind; Tkachev, Anatoly; Burkow, Ivan C

    2003-05-01

    The high levels of persistent organic pollutants have caused concern about human health, especially the health of the foetus and newborn child. This has especially been the case for Greenlandic and Canadian Inuits, where elevated levels of PCB and p,p'-DDE have been reported. In recent studies from arctic Russia the levels of beta-HCH and the DDT-group have been reported to be high, whereas the levels of PCB are low. However, the information from Northern Russia is, so far, incomplete. In this study, 27 delivering women from the city of Arkhangelsk, Russia, participated. They completed a questionnaire before delivery and plasma samples were collected after delivery. The analytical method developed to support this study involved gel permeation chromatography and silica gel purification, in addition to a traditional GC-MS method, and thus include acid labile compounds. The arithmetic mean levels of p,p'-DDE, beta-HCH and p,p'-DDT were 5.42, 3.59 and 1.17 microg/l, respectively. Toxaphene 26 and 50 were the only toxaphenes above the limit of detection, with arithmetic mean levels of 0.05 and 0.09 microg/l, respectively. Among the PCB congeners, PCB 138/163 was the most abundant with an arithmetic mean of 0.53 microg/l. The elevated levels of beta-HCH and p,p'-DDT as well as a low DDE/DDT ratio is a strong indication of fresh and maybe local sources in this area.

  3. The destruction of halogenated organic chemicals by plasma pyrolysis.

    PubMed

    Barton, T G; Mordy, J A

    1984-08-01

    Very high destruction efficiencies for halogenated chemicals have been achieved by plasma pyrolysis. Destruction efficiencies exceeded 99.9999999% for tests with polychlorinated biphenyls (PCBs). Preliminary tests with tetrachloromethane have obtained destruction efficiencies exceeding 99.99%. The plasma pyrolysis process involved the creation of a 250-kW plasma with a temperature in excess of 25 000 degrees C. The toxic material was injected into the plasma zone at a rate between 1 and 2 L/min. Thermochemical and photochemical dissociation of the toxic materials produced atoms and ions which recombined to form primarily H2, CO, HCl, and particulate carbon. The HCl was neutralized by NaOH. The flaring of the H2 and CO should destroy to a high degree any trace residuals. The application of plasma pyrolysis for the ultimate disposal of toxicological waste was also investigated. Rat carcasses containing mean lethal dosage of PCB were pyrolyzed.

  4. Plasma self-organization by maximum entropy production

    NASA Astrophysics Data System (ADS)

    Kim, Y.-B.

    2005-10-01

    Understanding turbulence saturation mechanism in magnetically confined plasma is one of the most important but unsolved problems in plasma physics research. The following hypothesis has been proposed as a possible turbulence saturation mechanism in confined plasma. The confined system filled with plasma, turbulent electromagnetic field and trace amount of neutral particles, e.g., magnetically confined thermonuclear system, will approach to the state of global maximum entry production. This hypothesis determines unique equilibrium plasma profiles without knowing detailed underlying turbulence dynamics in certain cases. This approach is different from the conventional picture of transport; in which source is balanced by linear thermodynamic forces and then transport coefficients are determined from either microscopic theory or experiment. The definition and evolution of entropy in this complex system is introduced and global entropy production rate is maximized under the constraint of particle, momentum, and energy conservation. Results from analytical and numerical calculus of variation will be discussed.

  5. A study of interfaces between organic and metal materials and their application in polymer light-emitting diodes and polymer photovoltaic solar cells

    NASA Astrophysics Data System (ADS)

    Li, Juo-Hao

    2009-12-01

    In the past few decades, it attracts a lot of attention for the researches of organic semiconductor due to its new and interesting properties, compared with conventional soft material and inorganic semiconductor. Several kinds of electronic devices such as light emitting diodes, thin film transistors and photovoltaic solar cell based on these organic semiconductors are also proposed and studied. This dissertation will focus on interface between organic and metal, which is one of the mysteries and critical issues remaining in the material properties and limiting the device performance. In the first chapter, a brief review and introduction of the organic semiconductor and organic electronics will be described. The purpose is to introduce the research background, motivation and methodology. Chapter two demonstrates the concept of top-emitting light-emitting diodes and the research focus on the interfaces between the light-emitting polymer and electrodes. An interfacial layer is introduced to improve the hole-injection from the anode. Except for alternating the electrode architecture, surface treatment or modification also have significant influences on interfacial electronic structure. Chapter three describes the discovery of solvent treatment on top of the light-emitting polymer and its application on organic electrophosphorescent devices. To further study the interfaces in organic electronics, an interface layer of sol-gel processed titanium oxide is introduced into organic electronic devices. Chapter four describes the amorphous titanium oxide and its application on polymer light-emitting diodes, while Chapter five demonstrates nanocrystalline titanium dioxide and its application in both light-emitting devices and polymer photovoltaic solar cells.

  6. 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

  7. 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

    2015-09-11

    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.

  8. Photocatalytic Anatase TiO2 Thin Films on Polymer Optical Fiber Using Atmospheric-Pressure Plasma.

    PubMed

    Baba, Kamal; Bulou, Simon; Choquet, Patrick; Boscher, Nicolas D

    2017-04-19

    Due to the undeniable industrial advantages of low-temperature atmospheric-pressure plasma processes, such as low cost, low temperature, easy implementation, and in-line process capabilities, they have become the most promising next-generation candidate system for replacing thermal chemical vapor deposition or wet chemical processes for the deposition of functional coatings. In the work detailed in this article, photocatalytic anatase TiO2 thin films were deposited at a low temperature on polymer optical fibers using an atmospheric-pressure plasma process. This method overcomes the challenge of forming crystalline transition metal oxide coatings on polymer substrates by using a dry and up-scalable method. The careful selection of the plasma source and the titanium precursor, i.e., titanium ethoxide with a short alkoxy group, allowed the deposition of well-adherent, dense, and crystalline TiO2 coatings at low substrate temperature. Raman and XRD investigations showed that the addition of oxygen to the precursor's carrier gas resulted in a further increase of the film's crystallinity. Furthermore, the films deposited in the presence of oxygen exhibited a better photocatalytic activity toward methylene blue degradation assumedly due to their higher amount of photoactive {101} facets.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Microtexturing of the Conductive PEDOT:PSS Polymer for Superhydrophobic Organic Electrochemical Transistors

    PubMed Central

    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

  14. Versatile dual organic interface layer for performance enhancement of polymer solar cells

    NASA Astrophysics Data System (ADS)

    Li, Zhiqi; Liu, Chunyu; Zhang, Zhihui; Li, Jinfeng; Zhang, Liu; Zhang, Xinyuan; Shen, Liang; Guo, Wenbin; Ruan, Shengping

    2016-11-01

    The electron transport layer plays a crucial role on determining electron injection and extraction, resulting from the effect of balancing charge transport and reducing the interfacial energy barrier. Decreasing the inherent incompatibility and enhancing electrical contact via employing appropriate buffer layer at the surface of hydrophobic organic active layer and hydrophilic inorganic electrode are also essential for charge collection. Herein, we demonstrate that an efficient dual polyelectrolytes interfacial layer composed of polyethylenimine (PEI) and conducting poly(9,9-dihexylfluorenyl-2,7-diyl) (PDHFD) is incorporated to investigate the interface energetics and electron transport in polymer solar cells (PSCs). The composited PEI/PDHFD interface layer (PPIL) overcomed the low conductivity of bare PEI polymer, which decreased series resistance and facilitated electron extraction at the ITO/PPIL-active layer interface. The introduction of the interface energy state of the PPIL reduced the work function of ITO so that it can mate the top of the valence band of the photoactive materials and promoted the formation of ohmic contact at ITO electrode interface. As a result, the composited PPIL tuned energy alignment and accelerated the electron transfer, leading to significantly increased photocurrent and power conversion efficiency (PCE) of the devices based on various representative polymer:fullerene systems.

  15. 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

  16. Thermally cross-linkable hole transport polymers for solution-based organic light-emitting diodes.

    PubMed

    Cha, Seung Ji; Cho, Se-Na; Lee, Woo-Hyung; Chung, Ha-Seul; Kang, In-Nam; Suh, Min Chul

    2014-04-01

    Two thermally cross-linkable hole transport polymers that contain phenoxazine and triphenylamine moieties, X-P1 and X-P2, are developed for use in solution-processed multi-stack organic light-emitting diodes (OLEDs). Both X-P1 and X-P2 exhibit satisfactory cross-linking and optoelectronic properties. The highest occupied molecular orbital (HOMO) levels of X-P1 and X-P2 are -5.24 and -5.16 eV, respectively. Solution-processed super yellow polymer devices (ITO/X-P1 or X-P2/PDY-132/LiF/Al) with X-P1 or X-P2 hole transport layers of various thicknesses are fabricated with the aim of optimizing the device characteristics. The fabricated multi-stack yellow devices containing the newly synthesized hole transport polymers exhibit satisfactory currents and power efficiencies. The optimized X-P2 device exhibits a device efficiency that is dramatically improved by more than 66% over that of a reference device without an HTL.

  17. Determining the chemical activity of hydrophobic organic compounds in soil using polymer coated vials

    PubMed Central

    Reichenberg, Fredrik; Smedes, Foppe; Jönsson, Jan-Åke; Mayer, Philipp

    2008-01-01

    Background In soils contaminated by hydrophobic organic compounds, the concentrations are less indicative of potential exposure and distribution than are the associated chemical activities, fugacities and freely dissolved concentrations. The latter can be measured by diffusive sampling into thin layers of polymer, as in, for example, solid phase micro-extraction. Such measurements require equilibrium partitioning of analytes into the polymer while ensuring that the sample is not depleted. We introduce the validation of these requirements based on parallel sampling into polymer layers of different thicknesses. Results Equilibrium sampling devices were made by coating glass vials internally with 3–12 μm thick layers of polydimethylsiloxane (PDMS). These were filled with slurries of a polluted soil and gently agitated for 5 days. The concentrations of 7 polycyclic aromatic hydrocarbons (PAHs) in the PDMS were measured. Validation confirmed fulfilment of the equilibrium sampling requirements and high measurement precision. Finally, chemical activities of the PAHs in the soil were determined from their concentrations and activity coefficients in the PDMS. Conclusion PAHs' thermodynamic activities in a soil test material were determined via a method of uptake into PDMS. This can be used to assess chemical exposure and predict diffusion and partitioning processes. PMID:18460193

  18. 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.

  19. Selective scattering polymer dispersed liquid crystal film for light enhancement of organic light emitting diode.

    PubMed

    Jiang, Jinghua; McGraw, Greg; Ma, Ruiqing; Brown, Julie; Yang, Deng-Ke

    2017-02-20

    We developed a novel light enhancing film for an organic light emitting diode (OLED) based on polymer dispersed liquid crystal (PDLC). In the film, the liquid crystal droplets are unidirectionally aligned along the film normal direction and exhibit selective scattering. The film scatters light emitted only in directions with large incident angles but not light emitted in directions with small incident angles. When the light is scattered, it changes propagation direction and exits the OLED. The PDLC film reduces the total internal reflection and thus can significantly increase the light efficiency of the OLED.

  20. A polymer with built-in charge for increasing the organic diode efficiency

    NASA Astrophysics Data System (ADS)

    Zajarskiy, Dmitriy A.; Ruzanov, Oleg M.; Fedorkov, Dmitriy A.; Petrov, Vladimir V.; Klimov, Boris N.

    2007-05-01

    In the present paper the problem which is important for modern microelectronics - a raise of effectiveness of carrier charge transfer by means of making an internal field is considered. For this purpose we create structures, which besides standard layers, such as HTL and ETL, contain layers consisting of polymers with the internal charge, such as PSS, PAH. Theoretical calculations show that the addition of these layers into multilayer OLED structures can lower potential energy barrier between organic layers and electrodes, and this will allow rising the effectiveness of the charge transfer emission and consequently also a number of excitons in working area of the display.

  1. 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.

  2. 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.

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

    PubMed

    Banerji, Natalie

    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.

  4. 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.

  5. Photo-triggered molecular release based on auto-degradable polymer-containing organic-inorganic hybrids.

    PubMed

    Okada, Hiroshi; Tanaka, Kazuo; Ohashi, Wataru; Chujo, Yoshiki

    2014-07-01

    The photo-triggered molecular release from the organic-inorganic polymer hybrids is presented in this manuscript. Initially, the preparation of the auto-degradable polymer is explained with the photo-cleavable group at the end of the polymer main-chain. The silica-based dye-loaded hybrids containing these polymers were fabricated. It was found that by UV irradiation, the end capping was removed, and then the auto-degradation occurs through the polymer main-chain. Finally, the molecular release of the loaded dyes was accomplished in various media by the UV irradiation. In particular, it was shown that both of hydrophobic and hydrophilic dyes can be applied in this system.

  6. Effect of hexafluoropropylene oxide plasma polymer particle coatings on the rheological properties of boron nitride/poly(dimethylsiloxane) composites.

    PubMed

    Bian, J F; Lujan, W R; Harper-Nixon, D; Jeon, H S; Weinkauf, D H

    2005-10-15

    This work explores the use of conformal nanoscale plasma coatings on the surface of boron nitride (BN) powders to control the rheological properties of BN/poly(dimethylsiloxane) (PDMS) composites. BN particles are conformally coated with hexafluoropropylene oxide (HFPO) in a tumbling RF-plasma reactor. Following the HFPO plasma treatment, XPS evidence indicates the presence of thin coating on the surface of the particles having a F:C ratio of 1.77. Filled BN/PDMS composites are investigated using oscillatory shear rheometry in the concentration range of 0.09-0.41 vol% (varphi). The addition of the plasma treated BN particles to the PDMS matrix reduces the complex viscosity by 40-60% when compared with equally loaded control samples across a broad concentration range. The frequency dependence of the maximum packing fraction (varphi(m)=0.38-0.42) is also observed for both treated and untreated particles. The maximum packing fraction does not appear to be significantly affected by the conformal plasma polymer treatment. The investigation has shown that the relative dynamic viscosity of the BN/PDMS can be described by the modified Mooney equation.

  7. 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

  8. Growth and assembly of functionalized nanomaterials: Using organic-inorganic polymer hybrid systems

    NASA Astrophysics Data System (ADS)

    Goel, Divya

    Precise positioning of metallic nanostructures on semiconductor surfaces is important for applications such as photovoltaics, metal interconnects, sensing platforms, and many others. The rising cost and complexity with lithographically defined structures demands a parallel fabrication process that enables easy scale up. Surface patterns formed by block copolymers are considered as a promising means to create functional nanoscopic structures needed for the fabrication of miniaturized devices. The integration of polymers with inorganic nano-materials could find widespread applications in scientific research because it provides a strategy to combine the use of polymers as hosts, and the optical, electronic, and catalytic properties of nanoparticles. This thesis explores a technique that employs patterns in block copolymers as a template for the directed self-assembly of the nanocrystals. One area investigated was the preparation of thermally stable nanoparticles that could be intercalated into block copolymers. Nanoparticles of various materials were synthesized in spherical and rod shapes with different aspect ratios. These particles were characterized by optical absorption measurements, scanning electron microscopy, high-resolution transmission electorn microscopy, and fluorescence spectroscopy. Methods were developed to functionalize these nanoparticles with thermally stable surface coatings using emulsion polymerization. A new method to control the size and spatial distribution of vertically aligned carbon nanofibers was developed, by intercalating nickel into a polymer film. Nanofibers were subsequently grown using plasma-enhanced chemical vapor deposition, and the properties of the nanofibers were characterized using TEM and electrochemical methods. The alignment of block copolymers normal to a dielectric thin film was demonstrated using AC electric fields. These studies demonstrated the underlying mechanism by which nanoscopic structure in thin films can be

  9. Radon 222 permeation through different polymers (PVC, EVA, PE and PP) after exposure to gamma radiation or surface treatment by cold plasma

    NASA Astrophysics Data System (ADS)

    Klein, D.; Tomasella, E.; Labed, V.; Meunier, C.; Cetier, Ph.; Robé, M. C.; Chambaudet, A.

    1997-08-01

    In order to limit radon emission during the storage of radioactive wastes and to comply with the different regulations in the storage facility, the packaging used for these types of wastes should include intermediate enclosures, such as polymer membranes used as radon barriers. However, the membrane would be subjected to different types of radiation during long periods of storage, it would have to be regularly monitored for damage. The first aim of this study is to check the efficiency and the continuity of such polymer membranes subjected to different accelerated ageing processes by exposure to gamma radiation. PolyVinyl Chloride (PVC) and Ethylene Vinyl Acetate (EVA) membranes were studied after gamma exposures. Thus, we evaluated the effects of the gamma radiations on the radon permeation coefficient, and the degradation of these polymers due to this exposure. The second objective of this study is to evaluate the modifications of the polymer surface by cold plasma. PolyEthylene (PE) and PolyPropylene (PP) membranes were studied. Exposure of a polymer to a plasma creates reactive sites on the polymer's surface. Different modifications in the surface composition (chemical composition, molecular weight, etc.) can be obtained. The advantage of the plasma process is that it acts within seconds and does not produce any noticeable effects on the bulk properties. The obtained results show that this treatment increases the polymer's efficiency as a radon barrier.

  10. 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. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  11. 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.

  12. Mechanistic studies of the structure-photostability relationship of organic conjugated polymers

    NASA Astrophysics Data System (ADS)

    Sanow, Logan Paul

    Organic Conjugated polymers (CPs) are a subject of intense research for their application in organic photovoltaics (OPVs), organic light emitting diodes (OLEDs), solid-state dye lasing, biological imaging and sensing, chemical sensing and remote sensing. CPs are key materials in the quest for more sustainable forms of renewable energy, making electronics more versatile and light weight, and increasing the functionality of everyday materials. For these applications and others that use CPs as the photoactive material, one of their main drawbacks is their susceptibility to photodegradation. Photodegradation occurs when the material is exposed to light leading to irreversible changes in the materials, most often resulting from photoxidation. These irreversible changes cause loss of mechanical, electronic and photophysical characteristics. For practical applications of CP devices, lifetime is as important as device efficiency. The following research is focused on studying the photodegradation mechanisms in various CPs to better understand the relationship between structure and stability, which may lead to the design of CPs which are more intrinsically photostable. To study how dependent photostability is on a polymer's chemical structure and frontier orbital energies, two series of CPs were studied. The first series contained two dicyano-substituted polyphenylenevinylene polymers with different side chains: poly(2,5-dioctyl-1,4-phenylene-1,2-dicyanovinylene) (C8-diCN-PPV) and poly(2,5-bis(decyloxy)-1,4-phenylene-1,2-dicyanovinylene) (RO-diCN-PPV). The second series included a well-known polymer, poly(3-hexylthiophene) (P3HT), and a newly synthesized CP, Poly(3,5-didodecyl-cyclopenta[2,1-b;3,4-b']dithiophen-4-one) (C6-CPDTO). The photodegradation mechanisms were studied through a combination of UV-Vis, PL, FTIR and NMR spectroscopy as well as gel permeation chromatography. There are two main degradation mechanisms that lead to photodegradation of CPs, the radical

  13. Organic Thin-Film Transistors with Phase Separation of Polymer-Blend Small-Molecule Semiconductors: Dependence on Molecular Weight and Types of Polymer

    NASA Astrophysics Data System (ADS)

    Ohe, Takahiro; Kuribayashi, Miki; Tsuboi, Ami; Satori, Kotaro; Itabashi, Masao; Nomoto, Kazumasa

    2009-12-01

    We have investigated effect of polymer on solution-processed organic thin-film transistors (TFTs) with polymer-blend semiconductors. Organic TFTs made from a solution of 6,13-bis(triisopropylsilylethynyl)-pentacene with a poly(α-methylstyrene) (PaMS) molecular weight of 20 k or above, exhibited mobility around 0.1 cm2/(V.s). On the other hand, the organic TFTs with a PaMS molecular weight of 2 k or with a poly(isobutyl methacrylate), exhibited much lower mobility. This can be explained in terms of the structure and crystallinity of the films. The results of film structure can be explained by applying the Flory-Huggins theory.

  14. Polymer-Metal-Organic Frameworks (polyMOFs) as Water Tolerant Materials for Selective Carbon Dioxide Separations.

    PubMed

    Zhang, Zhenjie; Nguyen, Ha Thi Hoang; Miller, Stephen A; Ploskonka, Ann M; DeCoste, Jared B; Cohen, Seth M

    2016-01-27

    Recently, polymer-metal-organic frameworks (polyMOFs) were reported as a new class of hybrid porous materials that combine advantages of both organic polymers and crystalline MOFs. Herein, we report a bridging coligand strategy to prepare new types of polyMOFs, demonstrating that polyMOFs are compatible with additional MOF architectures besides that of the earlier reported IRMOF-1 type polyMOF. Gas sorption studies revealed that these polyMOF materials exhibited relatively high CO2 sorption but very low N2 sorption, making them promising materials for CO2/N2 separations. Moreover, these polyMOFs demonstrated exceptional water stability attributed to the hydrophobicity of polymer ligands as well as the cross-linking of the polymer chains within the MOF.

  15. Structure and ionic interactions of organic-inorganic composite polymer electrolytes studied by solid-state NMR and Raman spectroscopy.

    PubMed

    Joo, Chan Gyu; Bronstein, Lyudmila M; Karlinsey, Robert L; Zwanziger, Josef W

    2002-01-01

    Solid-state NMR studies of composite polymer electrolytes are reported. The materials consist of polyethylene oxide and an organic inorganic composite, together with a lithium salt, and are candidates for electrolytes in solid-state lithium ion batteries. Silicon and aluminum MAS and multiple quantum MAS are used to characterize the network character of the organic-inorganic composite, and spin diffusion measurements are used to determine the nanostructure of the polymer/composite blending. Multiple quantum spin counting is used to measure the ion aggregation. The NMR results are supported by Raman spectra, calorimetry, and impedance spectroscopy. From these experiments it is concluded that the composite suppresses polymer crystallization without suppressing its local mobility, and also suppresses the tendency for the ions to aggregate. This polymer composite thus appears very promising for application in lithium ion batteries.

  16. Polymers Used as Fuel for Laser Plasma Thrusters in Small Satellites

    DTIC Science & Technology

    2006-09-12

    Structure of the investigated polymers. 7 One major part of this project consists in the selection and development of suitable polymers for the...carbon sooth used as absorber and the polymer, which also consists to major part of carbon (36 wt-%). The dopant particle distribution seems to have...shockwave of GAP+IR after irradiation with a fluence of 2.87 J/cm2 at 1064 nm. The shockwave can be separated into two parts , a smooth domain (1. domain

  17. Molecular Electronic Coupling Controls Charge Recombination Kinetics in Organic Solar Cells of Low Bandgap Diketopyrrolopyrrole, Carbazole, and Thiophene Polymers

    PubMed Central

    2013-01-01

    Low-bandgap diketopyrrolopyrrole- and carbazole-based polymer bulk-heterojunction solar cells exhibit much faster charge carrier recombination kinetics than that encountered for less-recombining poly(3-hexylthiophene). Solar cells comprising these polymers exhibit energy losses caused by carrier recombination of approximately 100 mV, expressed as reduction in open-circuit voltage, and consequently photovoltaic conversion efficiency lowers in more than 20%. The analysis presented here unravels the origin of that energy loss by connecting the limiting mechanism governing recombination dynamics to the electronic coupling occurring at the donor polymer and acceptor fullerene interfaces. Previous approaches correlate carrier transport properties and recombination kinetics by means of Langevin-like mechanisms. However, neither carrier mobility nor polymer ionization energy helps understanding the variation of the recombination coefficient among the studied polymers. In the framework of the charge transfer Marcus theory, it is proposed that recombination time scale is linked with charge transfer molecular mechanisms at the polymer/fullerene interfaces. As expected for efficient organic solar cells, small electronic coupling existing between donor polymers and acceptor fullerene (Vif < 1 meV) and large reorganization energy (λ ≈ 0.7 eV) are encountered. Differences in the electronic coupling among polymer/fullerene blends suffice to explain the slowest recombination exhibited by poly(3-hexylthiophene)-based solar cells. Our approach reveals how to directly connect photovoltaic parameters as open-circuit voltage to molecular properties of blended materials. PMID:23662167

  18. Quantitation of drugs via molecularly imprinted polymer solid phase extraction and electrospray ionization mass spectrometry: benzodiazepines in human plasma.

    PubMed

    Figueiredo, Eduardo Costa; Sparrapan, Regina; Sanvido, Gustavo Braga; Santos, Mariane Gonçalves; Arruda, Marco Aurélio Zezzi; Eberlin, Marcos Nogueira

    2011-09-21

    The association of solid phase extraction with molecularly imprinted polymers (MIP) and electrospray ionization mass spectrometry (ESI-MS) is applied to the direct extraction and quantitation of benzodiazepines in human plasma. The target analytes are sequestered by MIP and directly analyzed by ESI-MS. Due to the MIP highly selective extraction, ionic suppression during ESI is minimized; hence no separation is necessary prior to ESI-MS, which greatly increases analytical speed. Benzodiazepines (medazepam, nitrazepam, diazepam, chlordiazepoxide, clonazepam and midazolam) in human plasma were chosen as a proof-of-principle case of drug analyses by MIP-ESI-MS in a complex matrix. MIP-ESI-MS displayed good figures of merits for medazepam, nitrazepam, diazepam, chlordiazepoxide and midazolam, with analytical calibration curves ranging from 10 to 250 μg L(-1) (r > 0.98) with limit of quantification <10 μg L(-1) and acceptable within-day and between-day precision and accuracy.

  19. 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.

  20. 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.