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Sample records for azlactone-containing polymers combining

  1. Vinyl Dimethyl Azlactone-Containing Copolymers: Towards Bio-Inspired Surfaces/Polymer-Protein Conjugates

    Energy Technology Data Exchange (ETDEWEB)

    Messman, Jamie M [ORNL; Banaszak, Abigail [Clemson University; Barrninger, Joshua [Clemson University; Mays, Jimmy [ORNL; Kilbey, II, S Michael [ORNL

    2007-01-01

    Stimuli-responsive, vinyl dimethyl azlactone/vinyl pyrrolidone (VDMA/VP) copolymers have been prepared using free radical polymerization techniques. These copolymers are subsequently the basis for the design of polymer brushes where the system is composed of a polystyrene (PS) block and a VDMA/VP copolymer block. Copolymers have been prepared using reversible addition fragmentation chain transfer (RAFT) polymerization technique. Using a solvent that is selective for the VDMA/VP block, these PS-block-P[VDMA/VP] copolymers can be preferentially adsorbed at the solid-fluid interface through the PS block to form a polymer "brush". Because VDMA is known to quantitatively react with amines, exposure of the copolymer to a solution containing amino acids (e.g. glycine) yields a bio-functionalized polymer brush. In this paper we will report on the synthesis and characterization of VDMA/VP copolymers including compositional analysis using FTIR and NMR spectroscopies.

  2. Polymer Characterization by Combined Chromatography-Infrared Spectroscopy

    OpenAIRE

    Dwyer, James L.; Ming Zhou

    2011-01-01

    Infrared spectroscopy is widely used in the analysis and characterization of polymers. Polymer products are not a singular species, but rather, they are a population of polymer molecules varying in composition and configuration plus other added components. This paper describes instrumentation that provides the benefit or resolving polymer populations into discrete identifiable entities, by combining chromatographic separation with continuous spectra acquisition. The technology also provides a...

  3. Polymer Characterization by Combined Chromatography-Infrared Spectroscopy

    Directory of Open Access Journals (Sweden)

    James L. Dwyer

    2011-01-01

    Full Text Available Infrared spectroscopy is widely used in the analysis and characterization of polymers. Polymer products are not a singular species, but rather, they are a population of polymer molecules varying in composition and configuration plus other added components. This paper describes instrumentation that provides the benefit or resolving polymer populations into discrete identifiable entities, by combining chromatographic separation with continuous spectra acquisition. The technology also provides a way to determine the mass distribution of discrete components across the chromatographic distribution of a sample. Various examples of application of this technology to polymer products are described. Examples include additives analysis, resolution of polymer blends, composition characterization of copolymers, analysis of degradation byproducts, and techniques of analysis of reactive polymer systems.

  4. Combined photothermal lens and photothermal mirror characterization of polymers.

    Science.gov (United States)

    Aréstegui, Odon S; Poma, Patricia Y N; Herculano, Leandro S; Lukasievicz, Gustavo V B; Guimarães, Francine B; Malacarne, Luis C; Baesso, Mauro L; Bialkowski, Stephen E; Astrath, Nelson G C

    2014-01-01

    We propose a combined thermal lens and thermal mirror method as concurrent photothermal techniques for the physical characterization of polymers. This combined method is used to investigate polymers as a function of temperature from room temperature up to 170 °C. The method permits a direct determination of thermal diffusivity and thermal conductivity. Additional measurements of specific heat, linear thermal expansion, and temperature-dependent optical path change are also performed. A complete set of thermal, optical, and mechanical properties of polycarbonate and poly (methyl methacrylate) samples are obtained. Methods presented here can be useful for in situ characterization of semitransparent materials, where fast and non-contacting measurements are required. PMID:25014843

  5. Clay-biodegradable polymer combination for pollutant removal from water

    Directory of Open Access Journals (Sweden)

    M. F. Mohd Amin

    2015-09-01

    Full Text Available In this study, a new treatment alternative is investigated to remove micropollutants from wastewater effectively and in a more cost-effective way. A potential solution is the use of clay in combination with biodegradable polymeric flocculants. Flocculation is viewed as the best method to get the optimum outcome from the combination of clay with starch. Clay is naturally abundantly available and relatively inexpensive compared to the conventional adsorbents used. Experimental studies were carried out with four different clays to select the best clay for further optimisation. The atrazine removal achieved is in the range of 10–99 % based on the clay concentration of 10–50 g L−1. Optimisation of the best clay performer leads towards atrazine reduction of > 99 % with a dosage of 100 mg L−1. The best and underperforming clays were then tested in other experiments with the addition of cationic starch flocculants. In this experiment, the addition of a polymer increased the atrazine removal for the underperforming clay to 46 % with only 10 mg L−1 clay dosages. The clay flocculation test was also performed to test the flocculation efficiency of clays by the polymer. Approximately 80–84 % of the clay is flocculated, which shows exceptional flocculation efficiency in removing both clays and atrazine from the water matrices.

  6. Targeting angiogenesis-dependent calcified neoplasms using combined polymer therapeutics.

    Directory of Open Access Journals (Sweden)

    Ehud Segal

    Full Text Available BACKGROUND: There is an immense clinical need for novel therapeutics for the treatment of angiogenesis-dependent calcified neoplasms such as osteosarcomas and bone metastases. We developed a new therapeutic strategy to target bone metastases and calcified neoplasms using combined polymer-bound angiogenesis inhibitors. Using an advanced "living polymerization" technique, the reversible addition-fragmentation chain transfer (RAFT, we conjugated the aminobisphosphonate alendronate (ALN, and the potent anti-angiogenic agent TNP-470 with N-(2-hydroxypropylmethacrylamide (HPMA copolymer through a Glycine-Glycine-Proline-Norleucine linker, cleaved by cathepsin K, a cysteine protease overexpressed at resorption sites in bone tissues. In this approach, dual targeting is achieved. Passive accumulation is possible due to the increase in molecular weight following polymer conjugation of the drugs, thus extravasating from the tumor leaky vessels and not from normal healthy vessels. Active targeting to the calcified tissues is achieved by ALN's affinity to bone mineral. METHODS AND FINDING: The anti-angiogenic and antitumor potency of HPMA copolymer-ALN-TNP-470 conjugate was evaluated both in vitro and in vivo. We show that free and conjugated ALN-TNP-470 have synergistic anti-angiogenic and antitumor activity by inhibiting proliferation, migration and capillary-like tube formation of endothelial and human osteosarcoma cells in vitro. Evaluation of anti-angiogenic, antitumor activity and body distribution of HPMA copolymer-ALN-TNP-470 conjugate was performed on severe combined immunodeficiency (SCID male mice inoculated with mCherry-labeled MG-63-Ras human osteosarcoma and by modified Miles permeability assay. Our targeted bi-specific conjugate reduced VEGF-induced vascular hyperpermeability by 92% and remarkably inhibited osteosarcoma growth in mice by 96%. CONCLUSIONS: This is the first report to describe a new concept of a narrowly-dispersed combined

  7. Conductive polymer combined silk fiber bundle for bioelectrical signal recording.

    Directory of Open Access Journals (Sweden)

    Shingo Tsukada

    Full Text Available Electrode materials for recording biomedical signals, such as electrocardiography (ECG, electroencephalography (EEG and evoked potentials data, are expected to be soft, hydrophilic and electroconductive to minimize the stress imposed on living tissue, especially during long-term monitoring. We have developed and characterized string-shaped electrodes made from conductive polymer with silk fiber bundles (thread, which offer a new biocompatible stress free interface with living tissue in both wet and dry conditions.An electroconductive polyelectrolyte, poly(3,4-ethylenedioxythiophene-poly(styrenesulfonate (PEDOT-PSS was electrochemically combined with silk thread made from natural Bombyx mori. The polymer composite 280 µm thread exhibited a conductivity of 0.00117 S/cm (which corresponds to a DC resistance of 2.62 Mohm/cm. The addition of glycerol to the PEDOT-PSS silk thread improved the conductivity to 0.102 S/cm (20.6 kohm/cm. The wettability of PEDOT-PSS was controlled with glycerol, which improved its durability in water and washing cycles. The glycerol treated PEDOT-PSS silk thread showed a tensile strength of 1000 cN in both wet and dry states. Without using any electrolytes, pastes or solutions, the thread directly collects electrical signals from living tissue and transmits them through metal cables. ECG, EEG, and sensory evoked potential (SEP signals were recorded from experimental animals by using this thread placed on the skin. PEDOT-PSS silk glycerol composite thread offers a new class of biocompatible electrodes in the field of biomedical and health promotion that does not induce stress in the subjects.

  8. Conductive Polymer Combined Silk Fiber Bundle for Bioelectrical Signal Recording

    OpenAIRE

    Shingo Tsukada; Hiroshi Nakashima; Keiichi Torimitsu

    2012-01-01

    Electrode materials for recording biomedical signals, such as electrocardiography (ECG), electroencephalography (EEG) and evoked potentials data, are expected to be soft, hydrophilic and electroconductive to minimize the stress imposed on living tissue, especially during long-term monitoring. We have developed and characterized string-shaped electrodes made from conductive polymer with silk fiber bundles (thread), which offer a new biocompatible stress free interface with living tissue in bot...

  9. Combined nanoimprint and photolithography of integrated polymer optics

    DEFF Research Database (Denmark)

    Christiansen, Mads Brøkner; Schøler, Mikkel; Gersborg-Hansen, Morten;

    2007-01-01

    are defined in SU-8 resist, doped with Rhodamine 6G laser dye, shaped as planar slab waveguides on a Fused Silica buffer substrate, and with a lst-order DFB surface corrugation forming the laser resonator. When optically pumped at 532 nm, lasing is obtained in the wavelength range 560 nm -600 nm, determined...... by the grating period. Our results, where 20 laser devices are defined across a 10 cm diameter wafer substrate, demonstrate the feasibility of CNP for wafer-scale fabrication of advanced nano-structured active and passive polymer optical components....

  10. Clay-biodegradable polymer combination for pollutant removal from water

    OpenAIRE

    M. F. Mohd Amin; S. G. J. Heijman; L. C. Rietveld

    2015-01-01

    In this study, a new treatment alternative is investigated to remove micropollutants from wastewater effectively and in a more cost-effective way. A potential solution is the use of clay in combination with biodegradable polymeric flocculants. Flocculation is viewed as the best method to get the optimum outcome from the combination of clay with starch. Clay is naturally abundantly available and relatively inexpensive compared to the conven...

  11. Formation of Combined Surface Features of Protrusion Array and Wrinkles atop Shape-Memory Polymer

    Science.gov (United States)

    Sun, L.; Zhao, Y.; Huang, W. M.; Tong, T. H.

    We demonstrate a simple and cost-effective approach to realize two combined surface features of different scales together, namely submillimeter-sized protrusion array and microwrinkles, atop a polystyrene shape-memory polymer. Two different types of protrusions, namely flat-top protrusion and crown-shaped protrusion, were studied. The array of protrusions was produced by the Indentation-Polishing-Heating (IPH) process. Compactly packed steel balls were used for making array of indents. A thin gold layer was sputter deposited atop the polymer surface right after polishing. After heating for shape recovery, array of protrusions with wrinkles on the top due to the buckling of gold layer was produced.

  12. Combining nebulization-mediated transfection and polymer microarrays for the rapid determination of optimal transfection substrates.

    Science.gov (United States)

    Unciti-Broceta, Asier; Díaz-Mochón, Juan J; Mizomoto, Hitoshi; Bradley, Mark

    2008-01-01

    In this manuscript, we report how transfection efficiencies vary as a function of the substrate upon which cells adhere using a polymer microarray platform to allow rapid analysis of a large number of substrates. During these studies, traditional transfection protocols were nonsatisfactory, and thus we developed an approach in which an ultrasonic nebulizer was used to dispense lipoplexes onto cell-based microarrays in the absence of liquid. Under these conditions, droplets were directly deposited onto the cells thereby enhancing transfection. This approach was successfully applied to the transfection of various cell lines immobilized on a library of polyacrylates and permitted the identification of highly efficient transfection/polymer combinations, while showing that specific polymer-cell interactions may promote the efficacy of chemical transfection. PMID:18247582

  13. Pulmonary surfactant proteins and polymer combinations reduce surfactant inhibition by serum

    OpenAIRE

    Lu, Karen W.; Pérez-Gil, Jesús; Echaide, Mercedes; Taeusch, H. William

    2011-01-01

    Acute respiratory distress syndrome (ARDS) is an inflammatory condition that can be associated with capillary leak of serum into alveoli causing inactivation of surfactant. Resistance to inactivation is affected by types and concentrations of surfactant proteins, lipids, and polymers. Our aim was to investigate the effects of different combinations of these three components. A simple lipid mixture (DPPC/POPG) or a more complex lipid mixture (DPPC/POPC/POPG/cholesterol) was used. Native surfac...

  14. COMBINED MICROBIAL SURFACTANT-POLYMER SYSTEM FOR IMPROVED OIL MOBILITY AND CONFORMANCE CONTROL

    Energy Technology Data Exchange (ETDEWEB)

    Jorge Gabitto; Maria Barrufet

    2004-08-01

    Many domestic oil fields are facing abandonment even though they still contain two-thirds of their original oil. A significant number of these fields can yield additional oil using advanced oil recovery (AOR) technologies. To maintain domestic oil production at current levels, AOR technologies are needed that are affordable and can be implemented by independent oil producers of the future. Microbial enhanced oil recovery (MEOR) technologies have become established as cost-effective solutions for declining oil production. MEOR technologies are affordable for independent producers operating stripper wells and can be used to extend the life of marginal fields. The demonstrated versatility of microorganisms can be used to design advanced microbial systems to treat multiple production problems in complex, heterogeneous reservoirs. The proposed research presents the concept of a combined microbial surfactant-polymer system for advanced oil recovery. The surfactant-polymer system utilizes bacteria that are capable of both biosurfactant production and metabolically-controlled biopolymer production. This novel technology combines complementary mechanisms to extend the life of marginal fields and is applicable to a large number of domestic reservoirs. The research project described in this report is performed jointly by, Bio-Engineering Inc., a woman owned small business, Texas A&M University and Prairie View A&M University, a Historically Black College and University. This report describes the results of our laboratory work to grow microbial cultures and the work done on recovery experiments on core rocks. We have selected two bacterial strains capable of producing both surfactant and polymers. We have conducted laboratory experiments to determine under what conditions surfactants and polymers can be produced from one single strain. We have conduct recovery experiments to determine the performance of these strains under different conditions. Our results do not show a

  15. Polymer flooding effect of seepage characteristics of the second tertiary combined model of L oilfield block B

    Directory of Open Access Journals (Sweden)

    Huan ZHAO

    2015-06-01

    Full Text Available The second tertiary combined model is applied to develop the second and third type reservoirs which have more oil layer quantity and strong anisotropism, compared to the regular main reservoir with polymer injection, whose seepage characteristics of polymer-injection-after-water-drive shows a remarkable difference, in addition. This development appears to have a larger effect on the remaining oil development and production. Simulating the second tertiary combined model by reservoir numerical simulation under different polymer molecular weight, polymer concentration, polymer injection rate on the polymer injection period, conclusions of the influenced seepage characteristics of original and added perforated interval pressure and water saturation are drawn. The conclusion shows that the polymer molecular weight could influence water saturation of added perforated interval; polymer concentration makes a significant impact on reservoir pressure; polymer injection rate has a great influence on the separate rate of original and added perforated interval. This research provides firm science evidence to the theory of the second tertiary combined model to develop and enhance oil injection-production rate.

  16. Combining ibuprofen sodium with cellulosic polymers: a deep dive into mechanisms of prolonged supersaturation.

    Science.gov (United States)

    Terebetski, Jenna L; Michniak-Kohn, Bozena

    2014-11-20

    The combination of a highly soluble salt form of a drug with a polymeric precipitation inhibitor has the potential to prolong drug supersaturation even following salt disproportionation. In this study, dissolution profiles of ibuprofen sodium in the presence of various cellulosic polymers, including hydroxypropyl methylcellulose (HPMC), methylcellulose (MC), and hydroxypropyl cellulose (HPC), were examined in order to assess degree and duration of supersaturation. In addition, the roles that the polymers played in altering drug solubility, media viscosity, physical form, and particle morphology were also assessed. A deep dive into the mechanisms of supersaturation revealed that intermolecular hydrogen bonding between ibuprofen and HPMC was driving supersaturation through nucleation inhibition and crystal growth modification. Polymer viscosity was proposed as the primary factor prolonging supersaturation of ibuprofen in the presence of MC, while mechanisms other than hydrogen bonding were likely to be attributed to supersaturation with the most hydrophobic polymer evaluated, HPC. Overall, the study suggested that induction of intermolecular interactions between ibuprofen and HPMC were more effective at inhibiting nucleation and maintaining prolonged supersaturation than physical modulation of solution properties, such as viscosity. PMID:25219860

  17. Monolithic integrated four DFB lasers array with a polymer-based combiner for WDM applications

    Science.gov (United States)

    Toussaere, E.; Bouadma, N.; Zyss, J.

    1998-01-01

    Compact and low cost integrated photonic components will be of significant importance for a wider penetration of optical technologies into private customer access systems. Hybrid semiconductor/polymer integrated technologies are very promising to achieve this goal by virtue of the highly flexible nature of polymers at both molecular and material scale, of their compatibility with processing steps used in semiconductor technologies, and of their reasonably low cost. One example is an integrated semiconductor 4-wavelength laser array with a polymer based 1-4 passive optical combiner on the same substrate. The polymer waveguide structure is a polysulfone material stripe embedded in PMMA cladding layers, and the laser structure is a buried ridge stripe (BRS). The optical coupling between the active and passive elements is a butt-joint coupling via a reactive ion beam etched (RIBE) semiconductor mirror facet. Such a photonic integration simplifies the optical coupling between a laser array and single mode fibers, while reducing the packaging cost. This optical device has been achieved with interesting performances such as small dimension size (1.2 × 0.5 mm), low laser threshold current, and output powers for each laser from the polymeric waveguide port of at least 1.5 mW without additional on-chip optical amplification.

  18. Component dynamics in polymer blends a combined QENS and dielectric spectroscopy investigation

    CERN Document Server

    Hofmann, S; Arbe, A; Colmenero, J; Faragó, B

    2002-01-01

    The individual dynamics of the two constituents of a binary polymer blend was studied by means of quasielastic neutron scattering and dielectric spectroscopy (DS). The combination of neutron spin-echo and backscattering techniques allowed us to cover the complete crossover from entropy-driven chain dynamics on mesoscopic scales to the alpha relaxation on local length scales. The observed blending effects on the respective relaxation times suggest a purely dynamic origin of the dynamic heterogeneity in polymer blends at temperatures well above the glass-transition temperature without the need to assume local phase separation. In contrast, the results from DS experiments towards much lower temperatures indicate systematic deviations of the segmental dynamics in the blend from its mean-field-like behavior at high temperatures. This additionally increases the dynamic heterogeneity in the segmental dynamics of the two components in the mixture. In the case of the chain dynamics, no similar effect could be observed...

  19. COMBINED MICROBIAL SURFACTANT-POLYMER SYSTEM FOR IMPROVED OIL MOBILITY AND CONFORMANCE CONTROL

    Energy Technology Data Exchange (ETDEWEB)

    Jorge Gabitto; Maria Barrufet

    2005-08-01

    Many domestic oil fields are facing abandonment even though they still contain two-thirds of their original oil. A significant number of these fields can yield additional oil using advanced oil recovery (AOR) technologies. To maintain domestic oil production at current levels, AOR technologies are needed that are affordable and can be implemented by the independent oil producers of the future. Microbial enhanced oil recovery (MEOR) technologies have become established as cost-effective solutions for declining oil production. MEOR technologies are affordable for independent producers operating stripper wells and can be used to extend the life of marginal fields. The demonstrated versatility of microorganisms can be used to design advanced microbial systems to treat multiple production problems in complex, heterogeneous reservoirs. The proposed research presents the concept of a combined microbial surfactant-polymer system for advanced oil recovery. The surfactant-polymer system utilizes bacteria that are capable of both biosurfactant production and metabolically-controlled biopolymer production. This novel technology combines complementary mechanisms to extend the life of marginal fields and is applicable to a large number of domestic reservoirs. The research project described in this report was performed by Bio-Engineering Inc., a woman owned small business, Texas A&M University and Prairie View A&M University, a Historically Black College and University. This report describes the results of our laboratory work to grow microbial cultures, the work done on recovery experiments on core rocks, and computer simulations. We have selected two bacterial strains capable of producing both surfactant and polymers. We have conducted laboratory experiments to determine under what conditions surfactants and polymers can be produced from one single strain. We have conduct recovery experiments to determine the performance of these strains under different conditions. Our results

  20. Polymers on disordered hierarchical lattices: A nonlinear combination of random variables

    Energy Technology Data Exchange (ETDEWEB)

    Cook, J. (Commissariat a l' Energie Atomique, Gif-sur-Yvette (France) Univ. of Edinburgh (England)); Derrida, B. (Commissariat a l' Energie Atomique, Gif-sur-Yvette (France))

    1989-10-01

    The problem of directed polymers on disordered hierarchical and hypercubic lattices is considered. For the hierarchical lattices the problem can be reduced to the study of the stable laws for combining random variables in a nonlinear way. The authors present the results of numerical simulations of two hierarchical lattices, finding evidence of a phase transition in one case. For a limiting case they extend the perturbation theory developed by Derrida and Griffiths to nonzero temperature and to higher order and use this approach to calculate thermal and geometrical properties (overlaps) of the model. In this limit they obtain an interpolation formula, allowing one to obtain the noninteger moments of the partition function from the integer moments. They obtain bounds for the transition temperature for hierarchical and hypercubic lattices, and some similarities between the problem on the two different types of lattice are discussed.

  1. Synthetic approaches towards new polymer systems by the combination of living carbocationic and anionic polymerizations

    DEFF Research Database (Denmark)

    Feldthusen, Jesper; Ivan, Bela; Muller, Axel. H.E.;

    1996-01-01

    Recent efforts to obtain block copolymers by combination of living carbocationic and anionic polymerizations are presented.When tolyl-ended polyisobutylene was used as macroinitiator of anionic polymerization of methacrylate derivatives mixtures of homopolymers and block copolymers were formed due...... to incomplete lithiation of this chain end.In another approach a new functionalization method was developed by end-quenching living polyisobutylene with 1,1-diphenylethylene. After transformation of the groups into 2,2-diphenylvinyl end groups and lithiation polymers were synthesized from protected acrylate...... monomers. After partial deprotection a network could be formed by reaction with diisocyanate. Complete deprotection yielded a new amphiphilic network containing polyisobutylene and poly(2-hydroxyethyl) methacrylate segments crosslinked by urethane linkages....

  2. Combination of Natural and Thermosensitive Polymers in Flocculation of Fine Silica Dispersions

    Directory of Open Access Journals (Sweden)

    Angel Licea-Claverie

    2013-01-01

    Full Text Available A novel strategy for faster and better flocculation in solid-liquid separation processes is reported: the use of the natural polyelectrolyte chitosan (CH2500 in combination with the biocompatible thermosensitive polymer poly(N-vinylcaprolactam (PNVCL. Silica dispersions (Aerosil OX50 were used as model and evaluated by means of analytical centrifuge, laser diffraction, and turbidimetry studies. Results show that the sedimentation velocity is doubled by addition of PNVCL and that at 45°C the density of the sediment is 33% higher, as compared to the use of CH2500 only. This results from the temperature sensitive behavior of PNVCL that phase-separate expelling water at temperatures higher than its LCST (32–34°C leading to compaction of the flocs. By using this strategy the sediment is more compact, contains less water, and contains a very small amount of biodegradable CH2500 and biocompatible PNVCL.

  3. Fractional Separation of Polymers in Nanochannels: Combined Influence of Wettability and Structure

    CERN Document Server

    D, Sree Hari P; Chakraborty, Suman

    2016-01-01

    Trapping macromolecules in nanopits finds multifarious applications in polymer separation, filtering biomolecules etc. However, tuning the locomotion of polymers in channels of nanoscopic dimensions is greatly restricted by the comparative advective and diffusive components of velocities. Using the polymer affinity toward the solvent and the wall, and the polymer structure, a mechanism is proposed to induce selective trapping of polymers. Similar to fractional distillation of hydrocarbons based on molecular weight, a technique of fractional segregation, depending on the channel wettability of polymeric chains at different depths in a pit that is located perpendicular to the flow is suggested. Depending on the properties of the polymeric chains and the surface chemistry, the segregation of the polymer at a particular level in the pit can be predicted. This behaviour stems from the difference in polymer structure leading to a competition between wettability based trapping and entropic trapping. The results of t...

  4. Mechanisms behind injecting the combination of nano-clay particles and polymer solution for enhanced oil recovery

    Science.gov (United States)

    Khalili Nezhad, Seyyed Shahram; Cheraghian, Goshtasp

    2015-09-01

    Laboratory investigations and field applications have proved injection of polymer solution to be an effective means to improve oil recovery for reservoirs of medium oil viscosity. The incremental oil produced in this case is the result of an increase in areal and vertical sweep efficiencies. Biopolymers and synthetic polymers are the major categories used in the petroleum industry for specific reasons. Biopolymers like xanthan are limited in their application as they are more susceptible to biodegradation. Synthetic polymers like Hydrolyzed PolyAcrylaMide (HPAM) have a much wider application as they are less susceptible to biodegradation. Furthermore, development of nanotechnology has successfully provided technical and economical viable alternatives for present materials. The objective of this study is to investigate the effect of combining clay nanoparticles with polymer solution on oil recovery. This paper includes a history match of both one-dimensional and two-dimensional polymer floods using a three-dimensional numerical model for fluid flow and mass transport. Results indicated that the amount of polymer adsorption decreased when clay nanoparticles were added to the PolyAcrylaMide solution; however, mobility ratio improvement is believed to be the main contributor for the proposed method in order to enhance much oil recovery compared to xanthan flood and HPAM flood.

  5. Mechanisms behind injecting the combination of nano-clay particles and polymer solution for enhanced oil recovery

    Science.gov (United States)

    Khalili Nezhad, Seyyed Shahram; Cheraghian, Goshtasp

    2016-08-01

    Laboratory investigations and field applications have proved injection of polymer solution to be an effective means to improve oil recovery for reservoirs of medium oil viscosity. The incremental oil produced in this case is the result of an increase in areal and vertical sweep efficiencies. Biopolymers and synthetic polymers are the major categories used in the petroleum industry for specific reasons. Biopolymers like xanthan are limited in their application as they are more susceptible to biodegradation. Synthetic polymers like Hydrolyzed PolyAcrylaMide (HPAM) have a much wider application as they are less susceptible to biodegradation. Furthermore, development of nanotechnology has successfully provided technical and economical viable alternatives for present materials. The objective of this study is to investigate the effect of combining clay nanoparticles with polymer solution on oil recovery. This paper includes a history match of both one-dimensional and two-dimensional polymer floods using a three-dimensional numerical model for fluid flow and mass transport. Results indicated that the amount of polymer adsorption decreased when clay nanoparticles were added to the PolyAcrylaMide solution; however, mobility ratio improvement is believed to be the main contributor for the proposed method in order to enhance much oil recovery compared to xanthan flood and HPAM flood.

  6. Gamma scintigraphic evaluation of floating gastroretentive tablets of metformin HCl using a combination of three natural polymers in rabbits

    Science.gov (United States)

    Razavi, Mahboubeh; Karimian, Hamed; Yeong, Chai Hong; Chung, Lip Yong; Nyamathulla, Shaik; Noordin, Mohamed Ibrahim

    2015-01-01

    The present research was aimed at formulating a metformin HCl sustained-release formulation from a combination of polymers, using the wet granulation technique. A total of 16 formulations (F1–F16) were produced using different combinations of the gel-forming polymers: tamarind kernel powder, salep (palmate tubers of Orchis morio), and xanthan. Post-compression studies showed that there were no interactions between the active drug and the polymers. Results of in vitro drug-release studies indicated that the F10 formulation which contained 5 mg of tamarind kernel powder, 33.33 mg of xanthan, and 61.67 mg of salep could sustain a 95% release in 12 hours. The results also showed that F2 had a 55% similarity factor with the commercial formulation (C-ER), and the release kinetics were explained with zero order and Higuchi models. The in vivo study was performed in New Zealand White rabbits by gamma scintigraphy; the F10 formulation was radiolabeled using samarium (III) oxide (153Sm2O3) to trace transit of the tablets in the gastrointestinal tract. The in vivo data supported the retention of F10 formulation in the gastric region for 12 hours. In conclusion, the use of a combination of polymers in this study helped to develop an optimal gastroretentive drug-delivery system with improved bioavailability, swelling, and floating characteristics. PMID:26273196

  7. Selenium-Substituted Hydroxyapatite/Biodegradable Polymer/Pamidronate Combined Scaffold for the Therapy of Bone Tumour

    Directory of Open Access Journals (Sweden)

    Ewa Oledzka

    2015-09-01

    Full Text Available The present study evaluated a new concept of combined scaffolds as a promising bone replacement material for patients with a bone tumour or bone metastasis. The scaffolds were composed of hydroxyapatite doped with selenium ions and a biodegradable polymer (linear or branched, and contained an active substance—bisphosphonate. For this purpose, a series of biodegradable polyesters were synthesized through a ring-opening polymerization of ε-caprolactone or d,l-lactide in the presence of 2-hydroxyethyl methacrylate (HEMA or hyperbranched 2,2-bis(hydroxymethylpropionic acid polyester-16-hydroxyl (bis-MPA initiators, substances often used in the synthesis of medical materials. The polymers were obtained with a high yield and a number-average molecular weight up to 45,300 (g/mol. The combined scaffolds were then manufactured by a direct compression of pre-synthesized hydroxyapatite doped with selenite or selenate ions, obtained polymer and pamidronate as a model drug. It was found that the kinetic release of the drug from the scaffolds tested in vitro under physiological conditions is strongly dependent on the physicochemical properties and average molecular weight of the polymers. Furthermore, there was good correlation with the hydrolytic biodegradation results of the scaffolds fabricated without drug. The preliminary findings suggest that the fabricated combined scaffolds could be effectively used for the sustained delivery of bioactive molecules at bone defect sites.

  8. Design and Development of Transdermal Therapeutic system of Carvedilol using Combination of Natural and Synthetic Polymers

    Directory of Open Access Journals (Sweden)

    Patel DB

    2012-04-01

    Full Text Available The present study was mainly focused on investigating the influence of concentration and combinationof HPMC K4M, Carbopol 934P and Chitosan on physical characterization and drug release behavior ofcarvedilol transdermal films prepared by the solvent evaporation technique. The physicochemicalcompatibility of the drug and the polymers was studied by differential scanning calorimetry and infraredspectroscopy. The results suggested no physicochemical incompatibility between the drug and thepolymers. The prepared films were evaluated for physicochemical characteristics like weight variation,thickness, folding endurance, tensile strength, percentage moisture uptake, water vapor transmissionrate, percentage flatness and in vitro permeation study. In vitro permeation studies were performed byusing Franz diffusion cells. The drug release profiles of selected formulations were subjected to kinetictreatment using zero order, first order, Higuchi and korsmeyer’s peppas kinetic models. The resultsfollowed Higuchi kinetics (r2=0.951−0.995 and the mechanism of release was diffusion mediated.Based on physicochemical and in vitro permeation studies, transdermal film prepared by combination ofHPMC K4M and Chitosan with ratio 3:1 selected as optimized formulation shows the drug release morethan 24 hours with good flexibility and stability at 250C. The developed transdermal film increases theefficacy of carvedilol for the treatment of hypertension.

  9. Fabrication of a polymer-metal combined atomic force microscopy probe for coarse food surface imaging.

    Science.gov (United States)

    Kang, Hyen-Wook; Muramatsu, Hiroshi; Kwon, Young-Soo

    2013-05-01

    We fabricated a polymer-metal combined atomic force microscopy (AFM) probe by two steps; a polymeric resin was used at first step, and a metal-ion was used at second step which needs more fabricating time than the resin. At first step, we fabricated a cylindrical base on to a commercial cantilever. At second step, we fabricated a conical probe on to the fabricated cylindrical base. To make the conical probe composed with silver, a 0.2 M aqueous solution of silver nitrate (AgNO3) was used. A 50 microm length polymeric-metallic hybrid tip has been fabricated to observe large bio and food samples. Generally, the AFM images of bio/food samples show cliff-like sharp patters in vertical. However, the AFM image by fabricated long tip shows clear structure of each brown rice flours. As most of commercial tips have three-angular pyramidal, the scanned results should be influenced by the lateral face of the three-angular pyramid, which results in cliff-like images. Because the sample size is large, the side area of the sample was adversely affected by the pyramidal structure during imaging. This problem may be resolved by designing conical structure tips. As the conical structure has no edge, the AFM image becomes clear. The fabricated tip has conical structure, and a clear AFM image was achieved. PMID:23858900

  10. Effect of an acrylic resin combined with an antimicrobial polymer on biofilm formation

    Directory of Open Access Journals (Sweden)

    Juliê Marra

    2012-12-01

    Full Text Available OBJECTIVES: The purpose of this study was to evaluate the antimicrobial activity of an acrylic resin combined with an antimicrobial polymer poly (2-tert-butylaminoethyl methacrylate (PTBAEMA to inhibit Staphylococcus aureus, Streptococcus mutans and Candida albicans biofilm formation. MATERIAL AND METHODS: Discs of a heat-polymerized acrylic resin were produced and divided according to PTBAEMA concentration: 0 (control, 10 and 25%. The specimens were inoculated (10(7 CFU/mL and incubated at 37ºC for 48 h. After incubation, the wells were washed and each specimen was sonicated for 20 min. Replicate aliquots of resultant suspensions were plated at dilutions at 37ºC for 48 h. The number of colony-forming units (CFU was counted and expressed as log (CFU+1/mL and analyzed statistically with α=.05. RESULTS: The results showed that 25% PTBAEMA completely inhibited S. aureus and S. mutans biofilm formation. A significant reduction of log (CFU+1/mL in count of S. aureus (control: 7.9±0.8A; 10%: 3.8±3.3B and S. mutans (control: 7.5±0.7A; 10%: 5.1±2.7B was observed for the group containing 10% PTBAEMA (Mann-Whitney, p0.05, P=0.079. CONCLUSIONS: Acrylic resin combined with 10 and 25% of PTBAEMA showed significant antimicrobial activity against S. aureus and S. mutans biofilm, but it was inactive against the C. albicans biofilm.

  11. SAXS Combined with UV-vis Spectroscopy and QELS: Accurate Characterization of Silver Sols Synthesized in Polymer Matrices.

    Science.gov (United States)

    Bulavin, Leonid; Kutsevol, Nataliya; Chumachenko, Vasyl; Soloviov, Dmytro; Kuklin, Alexander; Marynin, Andrii

    2016-12-01

    The present work demonstrates a validation of small-angle X-ray scattering (SAXS) combining with ultra violet and visible (UV-vis) spectroscopy and quasi-elastic light scattering (QELS) analysis for characterization of silver sols synthesized in polymer matrices. Polymer matrix internal structure and polymer chemical nature actually controlled the sol size characteristics. It was shown that for precise analysis of nanoparticle size distribution these techniques should be used simultaneously. All applied methods were in good agreement for the characterization of size distribution of small particles (less than 60 nm) in the sols. Some deviations of the theoretical curves from the experimental ones were observed. The most probable cause is that nanoparticles were not entirely spherical in form. PMID:26815604

  12. Entangled Polymer Melts in Extensional Flow - Characterization by Combined Rheology and Small-Angle Neutron Scattering

    DEFF Research Database (Denmark)

    Mortensen, Kell; Kirkensgaard, Jacob JK; Hassager, Ole;

    molecules.We have targeted different systems: first a “simple” sample of homogeneous high-molar masspolymers, where only the central part of a fraction of the polymers were D-labelled with the aimto highlight the polymer deformation and avoid influence of fast relaxation near the polymerends [1]. Another...... network [2]. The structure andrheology are measured both as a function of stain flow velocity, final Hencky strain ratio andduring the relaxation after cessation of extensional flow....

  13. Use of polymer combinations in the preparation of solid dispersions of a thermally unstable drug by hot-melt extrusion

    Directory of Open Access Journals (Sweden)

    Jia Liu

    2013-07-01

    Full Text Available The objective of the study was to prepare solid dispersions containing a thermally unstable drug by hot-melt extrusion (HME. Carbamazepine (CBZ was selected as model drug and combinations of Kollidon VA64 (VA64, Soluplus (SOL and Eudragit EPO (EPO were utilized as carriers. Preformulation was conducted to identify the suitability of polymer combinations based on solubility parameters, differential scanning calorimetry (DSC, hot stage microscopy and thermogravimetric analysis. Physicochemical properties of solid dispersions were determined by DSC, X-ray diffraction, fourier transform infrared spectroscopy, dissolution and accelerated stability testing. The results show that drug-polymer miscibility at temperatures below the melting point (Tm of CBZ was improved by combining EPO with VA64 or SOL. With 30% drug loading in a solid dispersion in SOL:EPO (1:1, w/w, CBZ was mainly present in an amorphous form accompanied by a small amount of a microcrystalline form. The dissolution rate of the solid dispersion was significantly increased (approximately 90% within 5 min compared to either the pure drug (approximately 85% within 60 min or the corresponding physical mixture (approximately 80% within 60 min before and after storage. The solid dispersion in SOL:EPO (1:1, w/w was relatively stable at 40 °C/75% RH under CBZ tablet packaging conditions for at least 3 months. In conclusion, polymer combinations that improve drug-polymer miscibility at an HME processing temperature below the Tm of a drug appear to be beneficial in the preparation of solid dispersions containing thermally unstable drugs.

  14. A Combined Experimental and Numerical Approach to the Laser Joining of Hybrid Polymer - Metal Parts

    Science.gov (United States)

    Rodríguez-Vidal, E.; Lambarri, J.; Soriano, C.; Sanz, C.; Verhaeghe, G.

    A two-step method for the joining of opaque polymer to metal is presented. Firstly, the metal is structured locally on a micro-scale level, to ensure adhesion with the polymeric counterpart. In a second step, the opposite side of the micro-structured metal is irradiated by means of a laser source. The heat thereby created is conducted by the metal and results in the melting of the polymer at the interface. The polymer thereby adheres to the metal and flows into the previously engraved structures, creating an additional mechanical interlock between the two materials. The welding parameters are fine-tuned with the assistance of a finite element model, to ensure the required interface temperature. The method is illustrated using a dual phase steel joined to a fiber-reinforced polyamide. The effect of different microstructures, in particular geometry and cavity aspect ratio, on the joint's tensile-shear mechanical performance is discussed.

  15. Synthesis of Zwitterionic Polymer Particles via Combined Distillation Precipitation Polymerization and Click Chemistry for Highly Efficient Enrichment of Glycopeptide.

    Science.gov (United States)

    Liu, Jianxi; Yang, Kaiguang; Shao, Wenya; Li, Senwu; Wu, Qi; Zhang, Shen; Qu, Yanyan; Zhang, Lihua; Zhang, Yukui

    2016-08-31

    Because of the low abundance of glycopeptide in natural biological samples, methods for efficient and selective enrichment of glycopeptides play a significant role in mass spectrometry (MS)-based glycoproteomics. In this study, a novel kind of zwitterionic hydrophilic interaction chromatography polymer particles, namely, poly(N,N-methylenebisacrylamide-co-methacrylic acid)@l-Cys (poly(MBAAm-co-MAA)@l-Cys), for the enrichment of glycopeptides was synthesized by a facile and efficient approach that combined distillation precipitation polymerization (DPP) and "thiol-ene" click reaction. In the DPP approach, residual vinyl groups explored outside the core with high density, then the functional ligand cysteine was immobilized onto the surface of core particles by highly efficient thiol-ene click reaction. Taking advantage of the unique structure of poly(MBAAm-co-MAA)@l-Cys, the resulting particles possess remarkable enrichment selectivity for glycopeptides from the tryptic digested human immunoglobulin G. The polymer particles were successfully employed for the analysis of human plasma, and 208 unique glycopeptides corresponding to 121 glycoproteins were reliably identified in triple independent nano-LC-MS/MS runs. The selectivity toward glycopeptides of these particles poly(MBAAm-co-MAA)@l-Cys is ∼2 times than that of the commercial beads. These results demonstrated that these particles had great potential for large-scale glycoproteomics research. Moreover, the strategy with the combination of DPP and thiol-ene click chemistry might be a facile method to produce functional polymer particles for bioenrichment application. PMID:27498760

  16. Combined nano-imprint and photolithography (CNP) of integrated polymer optics

    DEFF Research Database (Denmark)

    Christiansen, Mads Brøkner; Schøler, Mikkel; Kristensen, Anders

    2007-01-01

    and substrate are separated, and the un-exposed resist is dissolved. Polymer waveguides are added to the system by an additional UV lithography step in a film of un-doped SU-8, which is spincoated on top of the lasers and substrate. When optically pumped at 532 nm, lasing is obtained in the wavelength range 559...... nm - 600 nm, determined by the grating period. Our results, where 20 laser devices are defined across a 10 cm diameter wafer substrate, demonstrate the feasibility of CNP for wafer-scale fabrication of advanced nano-structured active and passive polymer optical components....

  17. Stimuli-Responsive Layer-by-Layer Tellurium-Containing Polymer Films for the Combination of Chemotherapy and Photodynamic Therapy.

    Science.gov (United States)

    Fan, Fuqiang; Wang, Lu; Li, Feng; Fu, Yu; Xu, Huaping

    2016-07-01

    Tellurium-containing photoresponsive polyelectrolyte multilayer films were fabricated by layer-by-layer assembly of a tellurium-containing polymer, photosensitizer, and poly(styrenesulfonate). The resulting films were investigated by UV/vis spectroscopy, XPS, EPR, and fluorescence spectroscopy. Under visible light, the photosensitizer in the film is excited and transforms triplet oxygen into singlet oxygen in aqueous solution. Singlet oxygen oxidizes -Te- to high valence state (Te═O) on the polymer backbone. The generated (Te═O) group makes the micelles more hydrophilic and looser, thereby facilitating the controlled release of the loaded cargo of micelles. These results show that the film has the potential to be used for cargo loading and controlled release, thus may provide a new way to combine photodynamic therapy and chemotherapy. PMID:27301845

  18. REDV/Rapamycin-loaded polymer combinations as a coordinated strategy to enhance endothelial cells selectivity for a stent system.

    Science.gov (United States)

    Wei, Yu; Zhang, Jing-xun; Ji, Ying; Ji, Jian

    2015-12-01

    A major challenge in the development of drug eluting stent platform is the sustained inhibition of smooth muscle cell (SMC) proliferation while endothelial cell (EC) coverage is promoted. We demonstrated in this study that the combination of rapamycin-loaded polymer base layer and Arg-Glu-Asp-Val (REDV) peptide tethered top layer is a coordinated strategy to enhance EC-specific selectivity. A 2-methacryloyloxyethyl phosphorylcholine(MPC)-co-n-stearyl methacrylate (SMA) [PMS] film was prepared as a base coating to load rapamycin. MPC-co-SMA-co-p-nitrophenyloxycarbonyl polyethyleneglycol methacrylate (MEONP) [PMSN] was synthesized to form the top layer, which conjugated the EC-specific ligand REDV peptide that promotes EC attachment. The top layer functioned as a diffusion barrier, and the polymer film can sustain the rapamycin release of for over 120 days. The In vitro cell behavior of EC and SMC indicated that the rapamycin loaded polymer film inhibited cell growth in the first few days of drug release. After 8 days of drug release, the composite coating consistently resisted the nonspecific adsorption of SMC, whereas REDV enhanced EC attachment specifically. A rabbit iliac injury model was used to evaluate the in vivo of the application of this kind of surface-modified stainless steel stent. The composite polymer coating approach could significantly promote re-endothelialization without causing neointimal hyperplasia. The combination of an EC-specific ligand with rapamycin-loaded polymeric coating may potentially be an effective therapeutic alternative to improve currently available drug-eluting stents. PMID:26613858

  19. Combined main-chain/side-chain ionic liquid crystalline polymer based on ‘jacketing’ effect: Design, synthesis, supra-molecular self-assembly and photophysical properties

    Directory of Open Access Journals (Sweden)

    L. Weng

    2015-06-01

    Full Text Available Reasonably fabricating ordered structures of ionic polymers is very important for the development of novel functional materials. By combining the ions and liquid cry stalline polymer, we successfully designed and synthesized a series of novel combined main-chain/side-chain ionic liquid crystalline polymer (MCSC-ILCPs containing imidazolium groups and different counter-anions, poly (2,5-bis{[6-(4-butoxy-4'-imidazolium biphenylhexyl]oxycarbonyl}styrene salts poly(BImBHCS-X with the following types of counter-anions (Br¯, BF4¯, PF6¯ and TFSI¯. Combined technologies confirmed the chemical structures of the monomers and polymers with imidazolium cation and different counter-anions. Differential scanning calorimetry (DSC, polarized light microscopy (PLM and one- and two-dimensional wide-angle X-ray diffraction (1D and 2D WAXD results illustrated that the LC structures and the transitions of ordered structures depended on the nature of the counter-anion employed. The polymers with Br¯ and BF4¯ counter-anions exhibited smectic A (SmA LC behavior below the isotropic temperature. The another one, poly(BImBHCS–TFSI with the large volume of the TFSI¯ anion destroyed the packing of the LC ordered structure resulting in an amorphous structure. The photophysical properties of the polymers prepared can be adjusted by tuning the ionic interaction of the polymers by switching the counter-anion.

  20. Combination of Polymer Technology and Carbon Nanotube Array for the Development of an Effective Drug Delivery System at Cellular Level

    Directory of Open Access Journals (Sweden)

    Riggio Cristina

    2009-01-01

    Full Text Available Abstract In this article, a carbon nanotube (CNT array-based system combined with a polymer thin film is proposed as an effective drug release device directly at cellular level. The polymeric film embedded in the CNT array is described and characterized in terms of release kinetics, while in vitro assays on PC12 cell line have been performed in order to assess the efficiency and functionality of the entrapped agent (neural growth factor, NGF. PC12 cell differentiation, following incubation on the CNT array embedding the alginate delivery film, demonstrated the effectiveness of the proposed solution. The achieved results indicate that polymeric technology could be efficiently embedded in CNT array acting as drug delivery system at cellular level. The implication of this study opens several perspectives in particular in the field of neurointerfaces, combining several functions into a single platform.

  1. An immunochromatographic biosensor combined with a water-swellable polymer for automatic signal generation or amplification.

    Science.gov (United States)

    Kim, Kahee; Joung, Hyou-Arm; Han, Gyeo-Re; Kim, Min-Gon

    2016-11-15

    An immunochromatographic assay (ICA) strip is one of the most widely used platforms in the field of point-of-care biosensors for the detection of various analytes in a simple, fast, and inexpensive manner. Currently, several approaches for sequential reactions in ICA platforms have improved their usability, sensitivity, and versatility. In this study, a new, simple, and low-cost approach using automatic sequential-reaction ICA strip is described. The automatic switching of a reagent pad from separation to attachment to the test membrane was achieved using a water-swellable polymer. The reagent pad was dried with an enzyme substrate for signal generation or with signal-enhancing materials. The strip design and system operation were confirmed by the characterization of the raw materials and flow analysis. We demonstrated the operation of the proposed sensor by using various chemical reaction-based assays, including metal-ion amplification, enzyme-colorimetric reaction, and enzyme-catalyzed chemiluminescence. Furthermore, by employing C-reactive protein as a model, we successfully demonstrated that the new water-swellable polymer-based ICA sensor can be utilized to detect biologically relevant analytes in human serum. PMID:27203463

  2. Novel restricted access materials combined to molecularly imprinted polymers for selective solid-phase extraction of organophosphorus pesticides from honey.

    Science.gov (United States)

    He, Juan; Song, Lixin; Chen, Si; Li, Yuanyuan; Wei, Hongliang; Zhao, Dongxin; Gu, Keren; Zhang, Shusheng

    2015-11-15

    A novel restricted access materials (RAM) combined to molecularly imprinted polymers (MIPs), using malathion as template molecule and glycidilmethacrylate (GMA) as pro-hydrophilic co-monomer, were prepared for the first time. RAM-MIPs with hydrophilic external layer were characterized by scanning electron microscopy and recognition and selectivity properties were compared with the restricted access materials-non-molecularly imprinted polymers (RAM-NIPs) and unmodified MIPs. RAM-MIPs were used as the adsorbent enclosed in solid phase extraction column and several important extraction parameters were comprehensively optimized to evaluate the extraction performance. Under the optimum extraction conditions, RAM-MIPs exhibited comparable or even higher selectivity with greater extraction capacity toward six kinds of organophosphorus pesticides (including malathion, ethoprophos, phorate, terbufos, dimethoate, and fenamiphos) compared with the MIPs and commercial solid phase extraction columns. The RAM-MIPs solid phase extraction coupled with gas chromatography was successfully applied to simultaneously determine six kinds of organophosphorus pesticides from honey sample. The new established method showed good linearity in the range of 0.01-1.0 μg mL(-1), low limits of detection (0.0005-0.0019 μg mL(-1)), acceptable reproducibility (RSD, 2.26-4.81%, n = 6), and satisfactory relative recoveries (90.9-97.6%). It was demonstrated that RAM-MIPs solid phase extraction with excellent selectivity and restricted access function was a simple, rapid, selective, and effective sample pretreatment method.

  3. A new system for posterior restorations: a combination of ceramic optimized polymer and fiber-reinforced composite.

    Science.gov (United States)

    Rosenthal, L; Trinkner, T; Pescatore, C

    1997-01-01

    Due to the need for increased strength characteristics and enhanced aesthetic expectations of the patients, metal-free, aesthetic restorative systems for the anterior and posterior dentition are currently available. A new "space-age" restorative material has been developed that is a combination of a ceramic optimized polymer (Ceromer) (Targis/Vectris, Ivoclar Williams, Amherst, NY) and a fiber-reinforced composite framework material. The purpose of this article is to discuss the qualities that render this material particularly suitable for a variety of indications, including laboratory-fabricated restorations for the stress-bearing posterior regions. The material lends itself to diversification. Its indication for inlays, onlays, full-coverage crown restorations, and conservative single pontic inlay bridges is presented.

  4. Combining Berendsen Thermostat with Dissipative Particle Dynamics (DPD) for Polymer Simulation

    NARCIS (Netherlands)

    Moga, Sunita Andreea; Goga, Nicolae; Hadar, Anton

    2013-01-01

    In this article we present a new thermostat - theory and simulation results - obtained by combining two thermostats Berendsen and DPD types. The new thermostat provides a predictable behavior with temperatures that do not deviate from the reference and with thermal rate constant agreement between si

  5. VUV treatment combined with mechanical strain of stretchable polymer foils resulting in cell alignment

    Energy Technology Data Exchange (ETDEWEB)

    Barb, R.-A. [Institute of Applied Physics, Johannes Kepler University Linz (Austria); Magnus, B. [Innovacell Biotechnologie AG, Innsbruck (Austria); Innerbichler, S. [Innerbichler GmbH, Breitenbach am Inn (Austria); Greunz, T. [CDL-MS-MACH, Johannes Kepler University Linz (Austria); Wiesbauer, M. [Institute of Applied Physics, Johannes Kepler University Linz (Austria); Marksteiner, R. [Innovacell Biotechnologie AG, Innsbruck (Austria); Stifter, D. [CDL-MS-MACH, Johannes Kepler University Linz (Austria); Heitz, J., E-mail: johannes.heitz@jku.at [Institute of Applied Physics, Johannes Kepler University Linz (Austria)

    2015-01-15

    Highlights: • Elastic polyurethane (PU) foils were exposed to the vacuum-UV in reactive atmosphere. • The photomodification resulted in improved cytocompatibilty. • Parallel microgrooves formed on the irradiated PU surfaces after strong elongation. • Cells seeded onto microgrooves aligned their shapes in the direction of the grooves. • Elongation occurred also for cells on PU subjected to cyclic mechanical stretching. - Abstract: Cell-alignment along a defined direction can have a direct effect on the cell functionality and differentiation. Oriented micro- or nanotopographic structures on cell culture substrates can induce cell-alignment. Surface chemistry, wettability, and stiffness of the substrate are also important material features as they strongly influence the cell–substrate interactions. For improved bio-compatibility, highly elastic polyurethane (PU) foils were exposed to the vacuum-UV (VUV) light of a Xe{sub 2}{sup *} excimer lamp at 172 nm in a nitrogen containing atmosphere (N{sub 2} or NH{sub 3}). The irradiation resulted in a change in the chemical surface composition. Additionally, the formation of regular parallel microgrooves was observed on the irradiated surfaces after strong uni-axial deformation (i.e., more than about 50% strain) of the photo-modified PU foils. Cell seeding experiments demonstrated that the VUV modified polymer foils strongly enhance cell adhesion and proliferation. Cells seeded onto microgrooves aligned their shapes and elongated in the direction of the grooves. A similar effect was observed for cells seeded on photo-modified PU foils subjected to cyclic mechanical stretching at lower strain levels (i.e., typically 10% strain) without groove-formation. The cells had also here an elongated shape, however they not always align in a defined direction relative to the stretching.

  6. Super-resolution fluorescence imaging of nanoimprinted polymer patterns by selective fluorophore adsorption combined with redox switching

    KAUST Repository

    Yabiku, Y.

    2013-10-22

    We applied a super-resolution fluorescence imaging based on selective adsorption and redox switching of the fluorescent dye molecules for studying polymer nanostructures. We demonstrate that nano-scale structures of polymer thin films can be visualized with the image resolution better than 80 nm. The method was applied to image 100 nm-wide polymer nanopatterns fabricated by thermal nanoimprinting. The results point to the applicability of the method for evaluating residual polymer thin films and dewetting defect of the polymer resist patterns which are important for the quality control of the fine nanoimprinted patterns. 2013 Author(s).

  7. Combinational Effect of Cell Adhesion Biomolecules and Their Immobilized Polymer Property to Enhance Cell-Selective Adhesion

    Directory of Open Access Journals (Sweden)

    Rio Kurimoto

    2016-01-01

    Full Text Available Although surface immobilization of medical devices with bioactive molecules is one of the most widely used strategies to improve biocompatibility, the physicochemical properties of the biomaterials significantly impact the activity of the immobilized molecules. Herein we investigate the combinational effects of cell-selective biomolecules and the hydrophobicity/hydrophilicity of the polymeric substrate on selective adhesion of endothelial cells (ECs, fibroblasts (FBs, and smooth muscle cells (SMCs. To control the polymeric substrate, biomolecules are immobilized on thermoresponsive poly(N-isopropylacrylamide-co-2-carboxyisopropylacrylamide (poly(NIPAAm-co-CIPAAm-grafted glass surfaces. By switching the molecular conformation of the biomolecule-immobilized polymers, the cell-selective adhesion performances are evaluated. In case of RGDS (Arg-Gly-Asp-Ser peptide-immobilized surfaces, all cell types adhere well regardless of the surface hydrophobicity. On the other hand, a tri-Arg-immobilized surface exhibits FB-selectivity when the surface is hydrophilic. Additionally, a tri-Ile-immobilized surface exhibits EC-selective cell adhesion when the surface is hydrophobic. We believe that the proposed concept, which is used to investigate the biomolecule-immobilized surface combination, is important to produce new biomaterials, which are highly demanded for medical implants and tissue engineering.

  8. The Olefin Metathesis Reactions Combined with Organo-Iron Arene Activation Towards Dendrimers, and Polymers

    Science.gov (United States)

    Astruc, Didier; Martinez, Victor

    The subjects treated in the two lectures of the North Atlantic Treaty Organization (NATO) summer course are (1) the combination of arene activation and perfunctionalization using organo-iron chemistry with olefin metathesis incuding metathesis of dendritic polyolefin molecules; (2) the synthesis of metallodendritic benzylidene complexes that catalyse ring-opening metathesis polymerization (ROMP) under ambient conditions and the formation of dendritic stars; (3) the use of stoichiometric and catalytic electron-transfer processes with standard reservoirs of electrons (reductants) or electron holes (oxidants) iron complexes to achieve noteworthy metathesis reactions or synthesize compounds that are useful in metathesis. Only the two first topics are treated in this chapter, and interested readers can find references concerning the third aspect called in the introduction and subsequently cited in the reference list.

  9. Core-shell nanoscale coordination polymers combine chemotherapy and photodynamic therapy to potentiate checkpoint blockade cancer immunotherapy

    Science.gov (United States)

    He, Chunbai; Duan, Xiaopin; Guo, Nining; Chan, Christina; Poon, Christopher; Weichselbaum, Ralph R.; Lin, Wenbin

    2016-08-01

    Advanced colorectal cancer is one of the deadliest cancers, with a 5-year survival rate of only 12% for patients with the metastatic disease. Checkpoint inhibitors, such as the antibodies inhibiting the PD-1/PD-L1 axis, are among the most promising immunotherapies for patients with advanced colon cancer, but their durable response rate remains low. We herein report the use of immunogenic nanoparticles to augment the antitumour efficacy of PD-L1 antibody-mediated cancer immunotherapy. Nanoscale coordination polymer (NCP) core-shell nanoparticles carry oxaliplatin in the core and the photosensitizer pyropheophorbide-lipid conjugate (pyrolipid) in the shell (NCP@pyrolipid) for effective chemotherapy and photodynamic therapy (PDT). Synergy between oxaliplatin and pyrolipid-induced PDT kills tumour cells and provokes an immune response, resulting in calreticulin exposure on the cell surface, antitumour vaccination and an abscopal effect. When combined with anti-PD-L1 therapy, NCP@pyrolipid mediates regression of both light-irradiated primary tumours and non-irradiated distant tumours by inducing a strong tumour-specific immune response.

  10. Study on reinforced concrete beams strengthened using shape memory alloy wires in combination with carbon-fiber-reinforced polymer plates

    Science.gov (United States)

    Li, Hui; Liu, Zhi-qiang; Ou, Jin-ping

    2007-12-01

    It has been proven that carbon-fiber-reinforced polymer (CFRP) sheets or plates are capable of improving the strength of reinforced concrete (RC) structures. However, residual deformation of RC structures in service reduces the effect of CFRP strengthening. SMA can be applied to potentially decrease residual deformation and even close concrete cracks because of its recovery forces imposed on the concrete when heated. Therefore, a method of a RC structure strengthened by CFRP plates in combination with SMA wires is proposed in this paper. The strengthening effect of this method is investigated through experiments and numerical study based on the nonlinear finite element software ABAQUS in simple RC beams. Parametric analysis and assessment of damage by defining a damage index are carried out. The results indicate that recovery forces of SMA wires can decrease deflections and even close cracks in the concrete. The recovery rate of deflection of the beam increases with increasing the ratio of SMA wires. The specimen strengthened with CFRP plates has a relatively large stiffness and smaller damage index value when the residual deformation of the beam is first reduced by activation of the SMA wires. The effectiveness of this strengthening method for RC beams is verified by experimental and numerical results.

  11. Core-shell nanoscale coordination polymers combine chemotherapy and photodynamic therapy to potentiate checkpoint blockade cancer immunotherapy.

    Science.gov (United States)

    He, Chunbai; Duan, Xiaopin; Guo, Nining; Chan, Christina; Poon, Christopher; Weichselbaum, Ralph R; Lin, Wenbin

    2016-08-17

    Advanced colorectal cancer is one of the deadliest cancers, with a 5-year survival rate of only 12% for patients with the metastatic disease. Checkpoint inhibitors, such as the antibodies inhibiting the PD-1/PD-L1 axis, are among the most promising immunotherapies for patients with advanced colon cancer, but their durable response rate remains low. We herein report the use of immunogenic nanoparticles to augment the antitumour efficacy of PD-L1 antibody-mediated cancer immunotherapy. Nanoscale coordination polymer (NCP) core-shell nanoparticles carry oxaliplatin in the core and the photosensitizer pyropheophorbide-lipid conjugate (pyrolipid) in the shell (NCP@pyrolipid) for effective chemotherapy and photodynamic therapy (PDT). Synergy between oxaliplatin and pyrolipid-induced PDT kills tumour cells and provokes an immune response, resulting in calreticulin exposure on the cell surface, antitumour vaccination and an abscopal effect. When combined with anti-PD-L1 therapy, NCP@pyrolipid mediates regression of both light-irradiated primary tumours and non-irradiated distant tumours by inducing a strong tumour-specific immune response.

  12. Hybrid approach combining dissipative particle dynamics and finite-difference diffusion model: simulation of reactive polymer coupling and interfacial polymerization.

    Science.gov (United States)

    Berezkin, Anatoly V; Kudryavtsev, Yaroslav V

    2013-10-21

    A novel hybrid approach combining dissipative particle dynamics (DPD) and finite difference (FD) solution of partial differential equations is proposed to simulate complex reaction-diffusion phenomena in heterogeneous systems. DPD is used for the detailed molecular modeling of mass transfer, chemical reactions, and phase separation near the liquid∕liquid interface, while FD approach is applied to describe the large-scale diffusion of reactants outside the reaction zone. A smooth, self-consistent procedure of matching the solute concentration is performed in the buffer region between the DPD and FD domains. The new model is tested on a simple model system admitting an analytical solution for the diffusion controlled regime and then applied to simulate practically important heterogeneous processes of (i) reactive coupling between immiscible end-functionalized polymers and (ii) interfacial polymerization of two monomers dissolved in immiscible solvents. The results obtained due to extending the space and time scales accessible to modeling provide new insights into the kinetics and mechanism of those processes and demonstrate high robustness and accuracy of the novel technique.

  13. A light review on Polymer and CO2 Flooding (With Suggestion Combination of CO2 into Polymer Solution to Superior Flooding

    Directory of Open Access Journals (Sweden)

    O. Arjmand

    2012-08-01

    Full Text Available Today carbon dioxide (CO2 is one of displacing fluids that is used in Enhanced Oil Recovery (EOR process. However the low viscosity of CO2 causes it to finger towards the production well and bypassed large amounts of oil. Because of during flooding of CO2 its mobility is very less than crude oil into reservoir that causes to leave a great amount of oil, so a reduction in CO2 mobility would be inclined to mitigate. We in this review study state that could increase CO2 viscosity with dissolving it into polymer solution, that it can delay breakthrough time of CO2 during EOR process. In addition with making of such solution can decrease oil viscosity during flooding process into reservoir simultaneously. In actual with mixing of CO2 gas at high pressure into Partial Hydrolyzed Polyacrylamide solution (HPAM as an anionic polymer can increase the viscosity of CO2 with a concentration optimum of polymer and improve the sweep efficiency of oil during EOR process using this method.

  14. Is the combination of cellulosic polymers and anionic surfactants a good strategy for ensuring physical stability of BCS Class II drug nanosuspensions?

    Science.gov (United States)

    Bilgili, Ecevit; Li, Meng; Afolabi, Afolawemi

    2016-01-01

    Ensuring the physical stability of drug nanosuspensions prepared via wet media milling has been a challenge for pharmaceutical scientists. The aim of this study is to assess the combined use of non-ionic cellulosic polymers and anionic surfactants in stabilizing multiple drug nanosuspensions. Particle size of five drugs, i.e. azodicarbonamide (AZD), fenofibrate (FNB), griseofulvin (GF), ibuprofen (IBU) and phenylbutazone (PB) was reduced separately in an aqueous solution of hydroxypropyl cellulose (HPC) with/without sodium dodecyl sulfate (SDS) via a stirred media mill. Laser diffraction, scanning electron microscopy, thermal analysis, rheometry and electrophoresis were used to evaluate the breakage kinetics, storage stability, electrostatic repulsion and stabilizer adsorption. Without SDS, drug particles exhibited aggregation to different extents; FNB and GF particles aggregated the most due to low zeta potential and insufficient steric stabilization. Although aggregation in all milled suspensions was reduced due to HPC-SDS combination, FNB and IBU showed notable growth during 7-day storage. It is concluded that the combination of non-ionic cellulosic polymers and anionic surfactants is generally viable for ensuring the physical stability of wet-milled drug nanosuspensions, provided that the surfactant concentration is optimized to mitigate the Ostwald ripening, whereas cellulosic polymers alone may provide stability for some drug suspensions. PMID:25774989

  15. Is the combination of cellulosic polymers and anionic surfactants a good strategy for ensuring physical stability of BCS Class II drug nanosuspensions?

    Science.gov (United States)

    Bilgili, Ecevit; Li, Meng; Afolabi, Afolawemi

    2016-01-01

    Ensuring the physical stability of drug nanosuspensions prepared via wet media milling has been a challenge for pharmaceutical scientists. The aim of this study is to assess the combined use of non-ionic cellulosic polymers and anionic surfactants in stabilizing multiple drug nanosuspensions. Particle size of five drugs, i.e. azodicarbonamide (AZD), fenofibrate (FNB), griseofulvin (GF), ibuprofen (IBU) and phenylbutazone (PB) was reduced separately in an aqueous solution of hydroxypropyl cellulose (HPC) with/without sodium dodecyl sulfate (SDS) via a stirred media mill. Laser diffraction, scanning electron microscopy, thermal analysis, rheometry and electrophoresis were used to evaluate the breakage kinetics, storage stability, electrostatic repulsion and stabilizer adsorption. Without SDS, drug particles exhibited aggregation to different extents; FNB and GF particles aggregated the most due to low zeta potential and insufficient steric stabilization. Although aggregation in all milled suspensions was reduced due to HPC-SDS combination, FNB and IBU showed notable growth during 7-day storage. It is concluded that the combination of non-ionic cellulosic polymers and anionic surfactants is generally viable for ensuring the physical stability of wet-milled drug nanosuspensions, provided that the surfactant concentration is optimized to mitigate the Ostwald ripening, whereas cellulosic polymers alone may provide stability for some drug suspensions.

  16. Gamma scintigraphic evaluation of floating gastroretentive tablets of metformin HCl using a combination of three natural polymers in rabbits

    Directory of Open Access Journals (Sweden)

    Razavi M

    2015-08-01

    Full Text Available Mahboubeh Razavi,1 Hamed Karimian,1 Chai Hong Yeong,2 Lip Yong Chung,1 Shaik Nyamathulla,1 Mohamed Ibrahim Noordin1,3 1Department of Pharmacy, Faculty of Medicine, University of Malaya, 2Department of Biomedical Imaging and University Malaya Research Imaging Centre, Faculty of Medicine, University of Malaya, 3Center for Natural Products and Drug Discovery (CENAR, Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia Abstract: The present research was aimed at formulating a metformin HCl sustained-release formulation from a combination of polymers, using the wet granulation technique. A total of 16 formulations (F1–F16 were produced using different combinations of the gel-forming polymers: tamarind kernel powder, salep (palmate tubers of Orchis morio, and xanthan. Post-compression studies showed that there were no interactions between the active drug and the polymers. Results of in vitro drug-release studies indicated that the F10 formulation which contained 5 mg of tamarind kernel powder, 33.33 mg of xanthan, and 61.67 mg of salep could sustain a 95% release in 12 hours. The results also showed that F2 had a 55% similarity factor with the commercial formulation (C-ER, and the release kinetics were explained with zero order and Higuchi models. The in vivo study was performed in New Zealand White rabbits by gamma scintigraphy; the F10 formulation was radiolabeled using samarium (III oxide (153Sm2O3 to trace transit of the tablets in the gastrointestinal tract. The in vivo data supported the retention of F10 formulation in the gastric region for 12 hours. In conclusion, the use of a combination of polymers in this study helped to develop an optimal gastroretentive drug-delivery system with improved bioavailability, swelling, and floating characteristics. Keywords: gastroretentive drug delivery, gamma scintigraphy, sustain-release study, salep, tamarind seed, xanthan

  17. Fabrication of combined-scale nano- and microfluidic polymer systems using a multilevel dry etching, electroplating and molding process

    DEFF Research Database (Denmark)

    Tanzi, Simone; Østergaard, Peter Friis; Matteucci, Marco;

    2012-01-01

    Microfabricated single-cell capture and DNA stretching devices have been produced by injection molding. The fabrication scheme employed deep reactive ion etching in a silicon substrate, electroplating in nickel and molding in cyclic olefin polymer. This work proposes technical solutions to fabric......Microfabricated single-cell capture and DNA stretching devices have been produced by injection molding. The fabrication scheme employed deep reactive ion etching in a silicon substrate, electroplating in nickel and molding in cyclic olefin polymer. This work proposes technical solutions...

  18. Electrochromic properties of multicolored novel polymer synthesized via combination of benzotriazole and N-functionalized 2,5-di(2-thienyl)-1H-pyrrole units

    International Nuclear Information System (INIS)

    Synthesis of new conducting polymers is desired since their electrochemical and optical properties enable them to be used as active layers in many device applications. Benzotriazole and N-functionalized 2,5-di(2-thienyl)-1H-pyrrole (SNS Series) containing polymers showed very promising results as electrochromic materials. In order to observe the effect of the combination of these two units, three new monomers; 2-(6-(2,5-bis(5-methylthiophen-2-yl)-1H-pyrrol-1-yl)hexyl)-4,7-di (thiophen-2-yl)-2H benzo[d][1,2,3]triazole (M1), 2-(6-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)hexyl)-4,7-di(thiophen-2-yl) -2H-benzo[d][1,2,3]triazole (M2) and 2-(6-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)hexyl)-4,7-bis (5-methylthiophen-2-yl)-2H-benzo[d][1,2,3]triazole (M3) were synthesized. To better characterize the electronic and spectroscopic properties of the monomers, density functional theory (DFT) and its time-dependent generalization (TD-DFT) were used to calculate their vertical ionization potentials, vertical electron affinity and to simulate and interpret their infrared and UV-vis spectra. The monomers were electrochemically polymerized and the resultant polymers were characterized with cyclic voltammetry and UV-vis-NIR spectroscopy techniques. An electrochromic device was constructed with electrochemical polymer of M2. The device switched between red and blue colors and showed exceptional optical memory

  19. Combined novel methods for the determination of the humidification conditions of polymer electrolyte fuel cells; Kombination neuer Methoden zur Bestimmung des Wasserhaushaltes von Polymer-Elektrolyt-Brennstoffzellen

    Energy Technology Data Exchange (ETDEWEB)

    Kuhn, Robert Martin

    2011-05-02

    The water management is one of the key factors for the performance of a low temperature PEM fuel cell. With respect to the optimization of the fuel cell operation it is important to detect and differentiate water in the membrane, in the gas diffusion layer (GDL) and excess water in the flow field channel. The water content of each component influences the performance in different ways and adapted operation modes have to be kept. This work entitled 'Combined novel methods for the determination of the humidification conditions of PEM fuel cells' provides techniques and guidelines for fuel cell operation and will conclude in a straightforward control and operation strategy. Based on a combination of electrochemical impedance spectroscopy (EIS), locally resolved current distribution measurements and neutron radiography an informative basis for the determination of the water content of an operating PEM fuel cell is created. Special attention has been paid to the reproducibility and comparability in order to set up a consistent investigation and control strategy. (orig.)

  20. Antimocrobial Polymer

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, William F. (Utica, OH); Huang, Zhi-Heng (Walnut Creek, CA); Wright, Stacy C. (Columbus, GA)

    2005-09-06

    A polymeric composition having antimicrobial properties and a process for rendering the surface of a substrate antimicrobial are disclosed. The composition comprises a crosslinked chemical combination of (i) a polymer having amino group-containing side chains along a backbone forming the polymer, (ii) an antimicrobial agent selected from quaternary ammonium compounds, gentian violet compounds, substituted or unsubstituted phenols, biguanide compounds, iodine compounds, and mixtures thereof, and (iii) a crosslinking agent containing functional groups capable of reacting with the amino groups. In one embodiment, the polymer is a polyamide formed from a maleic anhydride or maleic acid ester monomer and alkylamines thereby producing a polyamide having amino substituted alkyl chains on one side of the polyamide backbone; the crosslinking agent is a phosphine having the general formula (A)3P wherein A is hydroxyalkyl; and the antimicrobial agent is chlorhexidine, dimethylchlorophenol, cetyl pyridinium chloride, gentian violet, triclosan, thymol, iodine, and mixtures thereof.

  1. Antimicrobial Polymer

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, William F. (Utica, OH); Wright, Stacy C. (Flint, MI); Taylor, Andrew C. (Ann Arbor, MI)

    2004-09-28

    A polymeric composition having antimicrobial properties and a process for rendering the surface of a substrate antimicrobial are disclosed. The polymeric composition comprises a crosslinked chemical combination of (i) a polymer having amino group-containing side chains along a backbone forming the polymer, (ii) an antimicrobial agent selected from metals, metal alloys, metal salts, metal complexes and mixtures thereof, and (iii) a crosslinking agent containing functional groups capable of reacting with the amino groups. In one example embodiment, the polymer is a polyamide formed from a maleic anhydride or maleic acid ester monomer and alkylamines thereby producing a polyamide having amino substituted alkyl chains on one side of the polyamide backbone; the crosslinking agent is a phosphine having the general formula (A).sub.3 P wherein A is hydroxyalkyl; and the metallic antimicrobial agent is selected from chelated silver ions, silver metal, chelated copper ions, copper metal, chelated zinc ions, zinc metal and mixtures thereof.

  2. Molecularly imprinted polymers combination with deep eutectic solvents for solid-phase extraction of caffeic acid from hawthorn.

    Science.gov (United States)

    Li, Guizhen; Tang, Weiyang; Cao, Weimin; Wang, Qian; Zhu, Tao

    2015-08-01

    Molecularly imprinted polymers (MIPs) with caffeic acid as template and non-imprinted polymers (NIPs) materials were prepared in the same procedure. Field emission scanning electron microscopy (FE-SEM) and adsorption capacity test were used to evaluate characteristic of the new materials. MIPs, NIPs and C18 were used for rapid purification of caffeic acid from hawthorn with solid-phase extraction ( SPE) , and extract yields of caffeic acid with the proposed materials were 3.46 µg/g, 1.01 µg/g and 1.17 µg/g, respectively. To optimize the MIPs-SPE procedures, different kinds of elution solutions were studied. Deep eutectic solvents (DESs) were prepared by choline chloride (ChCl)-glycerol (1/2, n/n) and choline chloride-urea (1/ 2, n/n). Methanol was mixed with the two kinds of DESs (glycerol-based DESs, urea-based DESs) in different ratios (0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, v/v), and they were used to investigated as elution solutions in the above MIPs-SPE procedures. The results showed that MIPs were potential SPE materials, and methanol/ glycerol-based DESs (3 :1, v/v) had the best elution capability with the recovery of 82.32%. PMID:26749853

  3. Structural determination of protein-based polymer blends with a promising tool: combination of FTIR and STXM spectroscopic imaging.

    Science.gov (United States)

    Ling, Shengjie; Qi, Zeming; Watts, Benjamin; Shao, Zhengzhong; Chen, Xin

    2014-05-01

    Fourier transform infrared (FTIR) and scanning transmission X-ray microscopy (STXM) spectroscopic imaging techniques are introduced to determine the structure of protein-based polymer blends, using the silk fibroin/polyethylene oxide (SF/PEO) blend as a model material. We demonstrate that FTIR and STXM imaging techniques provide complementary chemical sensitivities, resolution ranges and sample thickness requirements that can enable a greater understanding of SF/PEO blend films. From the FTIR images, we find that SF shows random coil and/or helical conformation in the SF-rich domains, and β-sheet conformation in the PEO-rich matrix. In the meantime, the SF content in SF-rich domains is 74 ± 4%, and 38 ± 6% in the PEO-rich matrix from the STXM images. These findings support and give further evidence to the conclusions of the previous studies on SF/PEO blends in the literature. Our results strongly suggest that FTIR and STXM imaging techniques are two promising complementary approaches for the study of phase behaviour and molecular conformation in protein-based polymer blend materials.

  4. The effect of polymer matrices on the thermal hazard properties of RDX-based PBXs by using model-free and combined kinetic analysis.

    Science.gov (United States)

    Yan, Qi-Long; Zeman, Svatopluk; Sánchez Jiménez, P E; Zhao, Feng-Qi; Pérez-Maqueda, L A; Málek, Jiří

    2014-04-30

    In this paper, the decomposition reaction models and thermal hazard properties of 1,3,5-trinitro-1,3,5-triazinane (RDX) and its PBXs bonded by Formex P1, Semtex 1A, C4, Viton A and Fluorel polymer matrices have been investigated based on isoconversional and combined kinetic analysis methods. The established kinetic triplets are used to predict the constant decomposition rate temperature profiles, the critical radius for thermal explosion and isothermal behavior at a temperature of 82°C. It has been found that the effect of the polymer matrices on the decomposition mechanism of RDX is significant resulting in very different reaction models. The Formex P1, Semtex and C4 could make decomposition process of RDX follow a phase boundary controlled reaction mechanism, whereas the Viton A and Fluorel make its reaction model shifts to a two dimensional Avrami-Erofeev nucleation and growth model. According to isothermal simulations, the threshold cook-off time until loss of functionality at 82°C for RDX-C4 and RDX-FM is less than 500 days, while it is more than 700 days for the others. Unlike simulated isothermal curves, when considering the charge properties and heat of decomposition, RDX-FM and RDX-C4 are better than RDX-SE in storage safety at arbitrary surrounding temperature. PMID:24657941

  5. Combined current and temperature mapping in an air-cooled, open-cathode polymer electrolyte fuel cell under steady-state and dynamic conditions

    Science.gov (United States)

    Meyer, Q.; Ronaszegi, K.; Robinson, J. B.; Noorkami, M.; Curnick, O.; Ashton, S.; Danelyan, A.; Reisch, T.; Adcock, P.; Kraume, R.; Shearing, P. R.; Brett, D. J. L.

    2015-11-01

    In situ diagnostic techniques provide a means of understanding the internal workings of fuel cells so that improved designs and operating regimes can be identified. Here, for the first time, a combined current density and temperature distributed measurement system is used to generate an electro-thermal performance map of an air-cooled, air-breathing polymer electrolyte fuel cell stack operating in an air/hydrogen cross-flow configuration. Analysis is performed in low- and high-current regimes and a complex relationship between localised current density, temperature and reactant supply is identified that describes the way in which the system enters limiting performance conditions. Spatiotemporal analysis was carried out to characterise transient operations in dead-ended anode/purge mode which revealed extensive current density and temperature gradients.

  6. A short review of radiation-induced raft-mediated graft copolymerization: A powerful combination for modifying the surface properties of polymers in a controlled manner

    Science.gov (United States)

    Barsbay, Murat; Güven, Olgun

    2009-12-01

    Surface grafting of polymeric materials is attracting increasing attention as it enables the preparation of new materials from known and commercially available polymers having desirable bulk properties such as thermal stability, elasticity, permeability, etc., in conjunction with advantageous newly tailored surface properties such as biocompatibility, biomimicry, adhesion, etc. Ionizing radiation, particularly γ radiation is one of the most powerful tools for preparing graft copolymers as it generates radicals on most substrates. With the advent of living free-radical polymerization techniques, application of γ radiation has been extended to a new era of grafting; grafting in a controlled manner to achieve surfaces with tailored and well-defined properties. This report presents the current use of γ radiation in living free-radical polymerization and highlights the use of both techniques together as a combination to present an advance in the ability to prepare surfaces with desired, tunable and well-defined properties.

  7. A short review of radiation-induced raft-mediated graft copolymerization: A powerful combination for modifying the surface properties of polymers in a controlled manner

    Energy Technology Data Exchange (ETDEWEB)

    Barsbay, Murat [Department of Chemistry, Hacettepe University, 06800 Beytepe, Ankara (Turkey)], E-mail: mbarsbay@hacettepe.edu.tr; Gueven, Olgun [Department of Chemistry, Hacettepe University, 06800 Beytepe, Ankara (Turkey)], E-mail: guven@hacettepe.edu.tr

    2009-12-15

    Surface grafting of polymeric materials is attracting increasing attention as it enables the preparation of new materials from known and commercially available polymers having desirable bulk properties such as thermal stability, elasticity, permeability, etc., in conjunction with advantageous newly tailored surface properties such as biocompatibility, biomimicry, adhesion, etc. Ionizing radiation, particularly {gamma} radiation is one of the most powerful tools for preparing graft copolymers as it generates radicals on most substrates. With the advent of living free-radical polymerization techniques, application of {gamma} radiation has been extended to a new era of grafting; grafting in a controlled manner to achieve surfaces with tailored and well-defined properties. This report presents the current use of {gamma} radiation in living free-radical polymerization and highlights the use of both techniques together as a combination to present an advance in the ability to prepare surfaces with desired, tunable and well-defined properties.

  8. Polymer films

    Science.gov (United States)

    Granick, Steve; Sukhishvili, Svetlana A.

    2008-12-30

    A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

  9. Structural and spectral properties of a zinc(II) coordination polymer: a combined experimental and theoretical study.

    Science.gov (United States)

    Hao, Jin-Ming; Li, Guang-Yue; Li, Yue-Hua; Cui, Guang Hua

    2014-10-15

    A novel 1D zinc(II) coordination polymer [Zn(bbbm)Cl2]n (where bbbm=1,4-bis(N-benzimidazolyl)butane) was synthetized by ZnCl2 and bbbm ligand under hydrothermal conditions, and its structural and spectral properties were studied by both experimental and theoretical techniques. The center zinc(II) ion displays four-coordinated in a tetrahedral geometry by two chloride anions and two N atoms of distinct bbbm ligands. Adjacent chains are further connected into a 2D layer structure through π-π stacking interactions. Vibrational frequencies of [Zn(bbbm)Cl2]n have been calculated using DFT/B3LYP/TZVP method, and well reproduced IR data. Furthermore, the vertical excitation energies from time-dependent DFT calculation confirmed that the fluorescent peaks at 385nm and 450nm could respectively be assigned to the π→π(*) transition within the bbbm ligands and π→n transition from chloride anion to bbbm ligand.

  10. Determination of 5-hydroxymethylfurfural using derivatization combined with polymer monolith microextraction by high-performance liquid chromatography.

    Science.gov (United States)

    Wu, Jian-Yuan; Shi, Zhi-Guo; Feng, Yu-Qi

    2009-05-27

    A simple and sensitive method for the determination of 5-hydroxymethylfurfural (HMF) in coffee, honey, beer, Coke, and urine by high-performance liquid chromatography (HPLC) is presented. This method is based on the formation of the 2,4-dinitrophenylhydrazone of HMF and subsequent polymer monolith microextraction (PMME) of this derivative. A poly(methacrylic acid-co-ethylene glycol dimethacrylate) (MAA-co-EGDMA) monolithic capillary column was selected as the extraction medium. Several parameters affecting the derivatization of HMF with 2,4-dinitrophenylhydrazine (DNPH) followed by extraction of the derivative were optimized. The procedure is simple and offers high sensitivity and specificity since the derivative of HMF is well preconcentrated by PMME with poly(MAA-co-EGDMA) monolith and well separated from the other components of the samples under examination. The recoveries in coffee, honey, beer, Coke, and urine samples were in the range of 83.9-110.8% spiked at different levels with HMF. The inter- and intraday precisions were less than 10%. The LOD (S/N = 3) and LOQ (S/N = 10) for HMF were 1.0 ng/mL and 3.4 ng/mL, respectively. PMID:19397264

  11. Combining RAFT polymerization and thiol-ene click reaction for core-shell structured polymer@BaTiO3 nanodielectrics with high dielectric constant, low dielectric loss, and high energy storage capability.

    Science.gov (United States)

    Yang, Ke; Huang, Xingyi; Zhu, Ming; Xie, Liyuan; Tanaka, Toshikatsu; Jiang, Pingkai

    2014-02-12

    Nanodielectric materials with high dielectric constant, low dielectric loss, and high energy storage capability are highly desirable in modern electric and electronics industries. It has been proved that the preparation of core-shell structured dielectric polymer nanocomposites via "grafting from" method is an effective approach to these materials. However, by using this approach, the deep understanding of the structure-dielectric property relationship of the core-shell structured nanodielectrics has been limited because of the lack of detailed information (e.g., molecular weight, grafting density) about the macromolecules grafted onto the nanoparticle surfaces. In this work, by the combination of reversible addition-fragmentation chain transfer (RAFT) polymerization and thiol-ene click reaction, two types of core-shell structured polymer@BaTiO3 (polymer@BT) nanocomposites with high dielectric constant and low dielectric loss were successfully prepared via a "grafting to" method. Compared with the "grafting from" method, this "grafting to" method has two merits: the molecular weight of the polymer chains in the shell layer can be easily controlled and the grafting density can be tailored by changing the molecular weight of the grafting polymer. Moreover, a clear insight into the relationship among the dielectric properties and energy storage capability of the core-shell structured polymer@BT nanocomposites, the molecular weight of the polymer chains, and the grafting density of the core-shell structured nanoparticles was achieved. The study provides new insights into the design and preparation of nanodielectric materials with desirable dielectric properties.

  12. The effect of polymer matrices on the thermal hazard properties of RDX-based PBXs by using model-free and combined kinetic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Qi-Long, E-mail: terry.well@163.com [Institute of Energetic Materials, Faculty of Chemical Technology, University of Pardubice, 53210 Pardubice (Czech Republic); Instituto de Ciencia de Materiales de Sevilla, CSIC-Universidad de Sevilla, C. Américo Vespucio No. 49, 41092 Sevilla (Spain); Zeman, Svatopluk, E-mail: svatopluk.zeman@upce.cz [Institute of Energetic Materials, Faculty of Chemical Technology, University of Pardubice, 53210 Pardubice (Czech Republic); Sánchez Jiménez, P.E. [Instituto de Ciencia de Materiales de Sevilla, CSIC-Universidad de Sevilla, C. Américo Vespucio No. 49, 41092 Sevilla (Spain); Zhao, Feng-Qi [Science and Technology on Combustion and Explosion Laboratory, Xi’an Modern Chemistry Research Institute, 710065 Xi’an (China); Pérez-Maqueda, L.A. [Instituto de Ciencia de Materiales de Sevilla, CSIC-Universidad de Sevilla, C. Américo Vespucio No. 49, 41092 Sevilla (Spain); Málek, Jiří [Department of Physical Chemistry, Faculty of Chemical Technology, University of Pardubice, 53210 Pardubice (Czech Republic)

    2014-04-01

    Highlights: • Nonisothermal decomposition kinetics of RDX and its PBXs has been investigated. • The kinetic models are determined by both master plot and combined kinetic analysis methods. • The constant rate temperature profiles and isothermal curves are predicted by obtained kinetic triplets. • The storage safety parameters are simulated based on thermal explosion theory. - Abstract: In this paper, the decomposition reaction models and thermal hazard properties of 1,3,5-trinitro-1,3,5-triazinane (RDX) and its PBXs bonded by Formex P1, Semtex 1A, C4, Viton A and Fluorel polymer matrices have been investigated based on isoconversional and combined kinetic analysis methods. The established kinetic triplets are used to predict the constant decomposition rate temperature profiles, the critical radius for thermal explosion and isothermal behavior at a temperature of 82 °C. It has been found that the effect of the polymer matrices on the decomposition mechanism of RDX is significant resulting in very different reaction models. The Formex P1, Semtex and C4 could make decomposition process of RDX follow a phase boundary controlled reaction mechanism, whereas the Viton A and Fluorel make its reaction model shifts to a two dimensional Avrami–Erofeev nucleation and growth model. According to isothermal simulations, the threshold cook-off time until loss of functionality at 82 °C for RDX-C4 and RDX-FM is less than 500 days, while it is more than 700 days for the others. Unlike simulated isothermal curves, when considering the charge properties and heat of decomposition, RDX-FM and RDX-C4 are better than RDX-SE in storage safety at arbitrary surrounding temperature.

  13. All Polymer Micropump

    OpenAIRE

    Hansen, Thomas Steen; Larsen, Niels Bent; Hassager, Ole

    2008-01-01

    In this thesis an all polymer micropump, and the fabrication method required to fabricate this, are examined. Polymer microfluidic. devices are of major scientific interest because they can combine complicated chemical and biological analys~s in cheap and disposable devices. The electrode system in the micropump is based on the conducting polymer poly(3,4 ethylenedioxythiophene) (PEDOT). The majority of the work conducted was therefore aimed at developing methods for patterning and processing...

  14. Energy-saving effect of a residential polymer electrolyte fuel cell cogeneration system combined with a plug-in hybrid electric vehicle

    International Nuclear Information System (INIS)

    Highlights: • Combined use of PEFC-CGS and PHEV is focused on for energy savings. • Optimal operational planning considering daily start–stop operation is modeled. • Charging PHEV with PEFC-CGS increases electric capacity factor of PEFC-CGS. • Combined use has higher energy-saving effect than their separate use. • Combined use synergistically saves energies in residential and transport sectors. - Abstract: The energy-saving effect of a residential polymer electrolyte fuel cell cogeneration system (PEFC-CGS) that adopts a daily start–stop operation with no reverse power flow, combined with a plug-in hybrid electric vehicle (PHEV) is analyzed by optimal operational planning model based on mixed-integer linear programming. This combined use aims to increase the electric capacity factor of the PEFC-CGS by charging the PHEV using the PEFC-CGS output late at night, and targets the application in regions where the reverse power flow from residential cogeneration systems to commercial electric power systems is not permitted, like in Japan. First, the optimal operational planning model that incorporates the daily start–stop operation of the PEFC-CGS is developed. The energy-saving effect of the combined use of the PEFC-CGS and PHEV is then analyzed on the basis of observations of the optimal operation patterns for a 0.75-kWe PEFC-CGS, a simulated energy demand with a sampling time of 5 min, and various daily running distances of the PHEV. The results show that the combined use of the PEFC-CGS and PHEV increases the electric capacity factor and hot water supply rate of the PEFC-CGS and saves more energy in comparison with their separate use in which the PEFC-CGS is used but the PHEV is charged only using purchased electric power. Consequently, this feasibility study reveals that the combined use of the PEFC-CGS and PHEV provides the synergistic effect on energy savings in the residential and transport sectors

  15. Determination of polymer size distribution by combination of quasielastic light scattering and band transport: evaluation of the effect of diffusion.

    Science.gov (United States)

    Wei, G J; Bloomfield, V A

    1979-01-01

    In this paper we report a computer simulation study of the effect of diffusion on the size distribution obtained by combining light scattering with isokinetic band sedimentation or electrophoresis. We find that, under typical experimental conditions, the method yields reasonably accurate size distributions for samples of particles greater than 10 nm radius. However, caution should be exercised in interpreting the results for smaller particles, for which the distortion due to diffusion can be considerable. PMID:16997189

  16. Hyaluronan-decorated polymer nanoparticles targeting the CD44 receptor for the combined photo/chemo-therapy of cancer

    Science.gov (United States)

    Maiolino, Sara; Moret, Francesca; Conte, Claudia; Fraix, Aurore; Tirino, Pasquale; Ungaro, Francesca; Sortino, Salvatore; Reddi, Elena; Quaglia, Fabiana

    2015-03-01

    In the attempt to develop novel concepts in designing targeted nanoparticles for combination therapy of cancer, we propose here CD44-targeted hyaluronan-decorated double-coated nanoparticles (dcNPs) delivering the lipophilic chemotherapeutic docetaxel (DTX) and an anionic porphyrin (TPPS4). dcNPs are based on electrostatic interactions between a negative DTX-loaded nanoscaffold of poly(lactide-co-glycolide), a polycationic shell of polyethyleneimine entangling negatively-charged TPPS4 and finally decorated with hyaluronan (HA) to promote internalization through CD44 receptor-mediated endocytosis. DTX/TPPS4-dcNPs, prepared through layer-by-layer deposition, showed a hydrodynamic diameter of around 180 nm, negative zeta potential and efficient loading of both DTX and TPPS4. DTX/TPPS4-dcNPs were freeze-dried with trehalose giving a powder that could be easily dispersed in different media. Excellent stability of dcNPs in specific salt- and protein-containing media was found. Spectroscopic behavior of DTX/TPPS4-dcNPs demonstrated a face-to-face arrangement of the TPPS4 units in non-photoresponsive H-type aggregates accounting for an extensive aggregation of the porphyrin embedded in the shell. Experiments in MDA-MB-231 cells overexpressing the CD44 receptor demonstrated a 9.4-fold increase in the intracellular level of TPPS4 delivered from dcNPs as compared to free TPPS4. Light-induced death increased tremendously in cells that had been treated with a combination of TPPS4 and DTX delivered through dcNPs as compared with free drugs, presumably due to efficient uptake and co-localization inside the cells. In perspective, the strategy proposed here to target synergistic drug combinations through HA-decorated nanoparticles seems very attractive to improve the specificity and efficacy of cancer treatment.In the attempt to develop novel concepts in designing targeted nanoparticles for combination therapy of cancer, we propose here CD44-targeted hyaluronan-decorated double

  17. In vitro evaluation of the effect of combination of hydrophilic and hydrophobic polymers on controlled release zidovudine matrix tablets

    Directory of Open Access Journals (Sweden)

    Ganesh S

    2008-01-01

    Full Text Available The aim of the present study was to prepare and characterize controlled-release matrix tablets of zidovudine using hydrophilic HPMC K4 M or Carbopol 934 alone or in combination with hydrophobic ethyl cellulose. Release kinetics was evaluated by using USP XXIV dissolution apparatus No.2 (paddle type. Scanning electron microscopy was used to visualize the effect of dissolution medium on matrix tablet surface. The in vitro results of controlled -release zidovudine tablets were compared with conventional marketed tablet Zidovir. The in vitro drug release study revealed that HPMC K4 M or Carbopol 934 preparation was able to sustain the drug release near to 6 hours. Combining HPMC K4 M or Carbopol 934 with ethyl cellulose sustained the drug release for nearly 12 h. The in vitro evaluation showed that the drug release may be by diffusion along with erosion. Results suggest that the developed controlled-release tablets of zidovudine could perform therapeutically better than marketed dosage forms, leading to improve efficacy, controlling the release and better patient compliance.

  18. Light-controlled drug releasing polymer films combining LbL self-assembly and host-guest interactions

    Directory of Open Access Journals (Sweden)

    J. Li

    2014-03-01

    Full Text Available By combining LbL (layer-by-layer self-assembly approach and host-guest interactions, a unique multilayer film was constructed and employed for a light-controlled drug release system. The drug molecules can be loaded and released into the resulting polyelectrolyte multilayers containing azobenzene (Azo function groups by using the irradiation of visible light and UV light alternately. The photo-sensitivity of the multilayer films was studied through UV-vis spectrum, fluorescence spectrum and confocal microscopy. The target molecules could be rapidly released from the multilayers after 300 W UV light irradiation for 20 minutes. Moreover, they could be readsorbed into the multilayers uniformly when illuminated under the 300 W visible light for 10 minutes confirmed by the observation of confocal microscopy, and the readsorption ratio exceeds 100% evidenced from UV–vis spectroscopy. After several cycles of the above-mentioned process, the multilayer films show good fatigue resistance. All these results indicate the photo-sensitivity and high-efficiency of the multilayer films, which have great potential in controlled drug delivery platform and biomedical applications.

  19. Perylene Bisimide as a Promising Zinc Oxide Surface Modifier: Enhanced Interfacial Combination for Highly Efficient Inverted Polymer Solar Cells.

    Science.gov (United States)

    Nian, Li; Zhang, Wenqiang; Wu, Siping; Qin, Leiqiang; Liu, Linlin; Xie, Zengqi; Wu, Hongbin; Ma, Yuguang

    2015-11-25

    We report the application of a perylene bisimide (PBI-H) as zinc oxide (ZnO) surface modifier to afford an organic-inorganic co-interlayer for highly efficient inverted organic photovoltaics (i-OPV). By thermal annealing, a N-Zn chemical bond formed between PBI-H and ZnO, inducing close organic-inorganic combination. In addition, this co-interlayer shows decreased work function and increased electron transportation and conductivity, which are benefits for the cathode to enhance charge extraction efficiency and decrease recombination losses. As a result a highly efficient i-OPV was achieved with a power conversion efficiency (PCE) of 9.43% based on this co-interlayer with PTB7:PC71BM as the active layer, which shows over 35% enhancement compared to that of the device without the PBI-H layer. Moreover, this co-interlayer was widely applicable for i-OPVs based on various material systems, such as P3HT:PC61BM and PTB7-Th:PC71BM, resulting in PCE as high as 4.78% and 10.31%, respectively.

  20. Porous bodies of hydroxyapatite produced by a combination of the gel-casting and polymer sponge methods.

    Science.gov (United States)

    González Ocampo, Jazmín I; Escobar Sierra, Diana M; Ossa Orozco, Claudia P

    2016-03-01

    A combination of gel-casting and polymeric foam infiltration methods is used in this study to prepare porous bodies of hydroxyapatite (HA), to provide a better control over the microstructures of samples. These scaffolds were prepared by impregnating a body of porous polyurethane foam with slurry containing HA powder, and using a percentage of solids between 40% and 50% w/v, and three different types of monomers to provide a better performance. X-Ray Diffraction (XRD), and Fourier Transformed Infrared (FTIR) and Scanning Electron Microscopy (SEM) were employed to evaluate both the powder hydroxyapatite and the scaffolds obtained. In addition, porosity and interconnectivity measurements were taken in accordance with the international norm. Bioactivity was checked using immersion tests in Simulated Body Fluids (SBF). After the sintering process of the porous bodies, the XRD results showed peaks characteristic of a pure and crystalline HA (JCPDS 9-432) as a single phase. SEM images indicate open and interconnected pores inside the material, with pore sizes between 50 and 600 μm. Also, SEM images demonstrate the relatively good bioactivity of the HA scaffolds after immersion in SBF. All results for the porous HA bodies suggest that these materials have great potential for use in tissue engineering. PMID:26966570

  1. Precursor polymer compositions comprising polybenzimidazole

    Energy Technology Data Exchange (ETDEWEB)

    Klaehn, John R.; Peterson, Eric S.; Orme, Christopher J.

    2015-07-14

    Stable, high performance polymer compositions including polybenzimidazole (PBI) and a melamine-formaldehyde polymer, such as methylated, poly(melamine-co-formaldehyde), for forming structures such as films, fibers and bulky structures. The polymer compositions may be formed by combining polybenzimidazole with the melamine-formaldehyde polymer to form a precursor. The polybenzimidazole may be reacted and/or intertwined with the melamine-formaldehyde polymer to form the polymer composition. For example, a stable, free-standing film having a thickness of, for example, between about 5 .mu.m and about 30 .mu.m may be formed from the polymer composition. Such films may be used as gas separation membranes and may be submerged into water for extended periods without crazing and cracking. The polymer composition may also be used as a coating on substrates, such as metal and ceramics, or may be used for spinning fibers. Precursors for forming such polymer compositions are also disclosed.

  2. Polymer fractionation

    Energy Technology Data Exchange (ETDEWEB)

    Hadermann, A. F.

    1985-04-09

    Soluble polymers are fractionated according to molecular weight by cryogenically comminuting the polymer and introducing the polymer particles, while still in the active state induced by cryogenic grinding, into a liquid having a solvent power selected to produce a coacervate fraction containing high molecular weight polymer species and a dilute polymer solution containing lower molecular weight polymer species. The coacervate may be physically separated from the solution and finds use in the production of antimisting jet fuels and the like.

  3. Polymer Nanocomposite Film with Metal Rich Surface Prepared by In Situ Single-Step Formation of Palladium Nanoparticles: An Interesting Way to Combine Specific Functional Properties

    Directory of Open Access Journals (Sweden)

    David Thompson

    2016-10-01

    Full Text Available This paper presents a continuous single-step route that permits preparation of a thermostable polymer/metal nanocomposite film and to combine different functional properties in a unique material. More precisely, palladium nanoparticles are in situ generated in a polyimide matrix thanks to a designed curing cycle which is applied to a polyamic acid/metal precursor solution cast on a glass plate. A metal-rich surface layer which is strongly bonded to the bulk film is formed in addition to homogeneously dispersed metal nanoparticles. This specific morphology leads to obtaining an optically reflective film. The metal nanoparticles act as gas diffusion barriers for helium, oxygen, and carbon dioxide; they induce a tortuosity effect which allows dividing the gas permeation coefficients by a factor near to 2 with respect to the neat polyimide matrix. Moreover, the ability of the in situ synthesized palladium nanoparticles to entrap hydrogen is evidenced. The nanocomposite film properties can be modulated as a function of the location of the film metal-rich surface with respect to the hydrogen feed. The synthesized nanocomposite could represent a major interest for a wide variety of applications, from specific coatings for aerospace or automotive industry, to catalysis applications or sensors.

  4. Improving Drug Loading of Mucosal Solvent Cast Films Using a Combination of Hydrophilic Polymers with Amoxicillin and Paracetamol as Model Drugs

    Directory of Open Access Journals (Sweden)

    Joshua Boateng

    2013-01-01

    Full Text Available Solvent cast mucosal films with improved drug loading have been developed by combining carboxymethyl cellulose (CMC, sodium alginate (SA, and carrageenan (CAR using paracetamol and amoxicillin as model drugs and glycerol (GLY as plasticizer. Films were characterized using X-ray powder diffraction (XRPD, scanning electron microscopy (SEM, folding resilience, swelling capacity, mucoadhesivity, and drug dissolution studies. SA, CMC, and GLY (5 : 3 : 6 films showed maximum amoxicillin loading of 26.3% whilst CAR, CMC, and GLY (1 : 2 : 3 films had a maximum paracetamol loading of 40%. XRPD analysis showed different physical forms of the drugs depending on the amount loaded. Films containing 29.4% paracetamol and 26.3% amoxicillin showed molecular dispersion of the drugs while excess paracetamol was observed on the film surface when the maximum 40% was loaded. Work of adhesion was similar for blank films with slightly higher cohesiveness for CAR and CMC based films, but the differences were significant between paracetamol and amoxicillin containing films. The stickiness and cohesiveness for drug loaded films were generally similar with no significant differences. The maximum percentage cumulative drug release was 84.65% and 70.59% for paracetamol and amoxicillin, respectively, with anomalous case two transport mechanism involving both drug diffusion and polymer erosion.

  5. Development of a model for the rational design of molecular imprinted polymer: Computational approach for combined molecular dynamics/quantum mechanics calculations

    Energy Technology Data Exchange (ETDEWEB)

    Dong Cunku [Department of Chemistry, Harbin Institute of Technology, Harbin 150090 (China); Li Xin, E-mail: lixin@hit.edu.cn [Department of Chemistry, Harbin Institute of Technology, Harbin 150090 (China); Guo Zechong [School of Municipal Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China); Qi Jingyao, E-mail: jyq@hit.edu.cn [School of Municipal Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China)

    2009-08-04

    A new rational approach for the preparation of molecularly imprinted polymer (MIP) based on the combination of molecular dynamics (MD) simulations and quantum mechanics (QM) calculations is described in this work. Before performing molecular modeling, a virtual library of functional monomers was created containing forty frequently used monomers. The MD simulations were first conducted to screen the top three monomers from virtual library in each porogen-acetonitrile, chloroform and carbon tetrachloride. QM simulations were then performed with an aim to select the optimum monomer and progen solvent in which the QM simulations were carried out; the monomers giving the highest binding energies were chosen as the candidate to prepare MIP in its corresponding solvent. The acetochlor, a widely used herbicide, was chosen as the target analyte. According to the theoretical calculation results, the MIP with acetochlor as template was prepared by emulsion polymerization method using N,N-methylene bisacrylamide (MBAAM) as functional monomer and divinylbenzene (DVB) as cross-linker in chloroform. The synthesized MIP was then tested by equilibrium-adsorption method, and the MIP demonstrated high removal efficiency to the acetochlor. Mulliken charge distribution and {sup 1}H NMR spectroscopy of the synthesized MIP provided insight on the nature of recognition during the imprinting process probing the governing interactions for selective binding site formation at a molecular level. We think the computer simulation method first proposed in this paper is a novel and reliable method for the design and synthesis of MIP.

  6. Performance enhancement of polymer electrolyte fuel cells by combining liquid removal mechanisms of a gas diffusion layer with wettability distribution and a gas channel with microgrooves

    Science.gov (United States)

    Utaka, Yoshio; Koresawa, Ryo

    2016-08-01

    Although polymer electrolyte fuel cells (PEFCs) are commercially available, there are still many problems that need to be addressed to improve their performance and increase their usage. At a high current density, generated water accumulates in the gas diffusion layer and in the gas channels of the cathode. This excess water obstructs oxygen transport, and as a result, cell performance is greatly reduced. To improve the cell performance, the effective removal of the generated water and the promotion of oxygen diffusion in the gas diffusion layer (GDL) are necessary. In this study, two functions proposed in previous reports were combined and applied to a PEFC: a hybrid GDL to form an oxygen diffusion path using a wettability distribution and a gas separator with microgrooves to enhance liquid removal. For a PEFC with a hybrid GDL and a gas separator with microgrooves, the concentration overvoltage of the PEFC was reduced, and the current density limit and maximum power density were increased compared with a conventional PEFC. Moreover, the stability of the cell voltage was markedly improved.

  7. Fire-safe polymers and polymer composites

    Science.gov (United States)

    Zhang, Huiqing

    The intrinsic relationships between polymer structure, composition and fire behavior have been explored to develop new fire-safe polymeric materials. Different experimental techniques, especially three milligram-scale methods---pyrolysis-combustion flow calorimetry (PCFC), simultaneous thermal analysis (STA) and pyrolysis GC/MS---have been combined to fully characterize the thermal decomposition and flammability of polymers and polymer composites. Thermal stability, mass loss rate, char yield and properties of decomposition volatiles were found to be the most important parameters in determining polymer flammability. Most polymers decompose by either an unzipping or a random chain scission mechanism with an endothermic decomposition of 100--900 J/g. Aromatic or heteroaromatic rings, conjugated double or triple bonds and heteroatoms such as halogens, N, O, S, P and Si are the basic structural units for fire-resistant polymers. The flammability of polymers can also be successfully estimated by combining pyrolysis GC/MS results or chemical structures with TGA results. The thermal decomposition and flammability of two groups of inherently fire-resistant polymers---poly(hydroxyamide) (PHA) and its derivatives, and bisphenol C (BPC II) polyarylates---have been systematically studied. PHA and most of its derivatives have extremely low heat release rates and very high char yields upon combustion. PHA and its halogen derivatives can completely cyclize into quasi-polybenzoxazole (PBO) structures at low temperatures. However, the methoxy and phosphate derivatives show a very different behavior during decomposition and combustion. Molecular modeling shows that the formation of an enol intermediate is the rate-determining step in the thermal cyclization of PHA. BPC II-polyarylate is another extremely flame-resistant polymer. It can be used as an efficient flame-retardant agent in copolymers and blends. From PCFC results, the total heat of combustion of these copolymers or blends

  8. Functional polymer blends and nanocomposites

    OpenAIRE

    Weder, Christoph

    2010-01-01

    The broad class of (multi)functional polymers with unusual combinations of optical, electronic, mechanical and other properties is attracting significant interest, because it conceptually combines the advantages of polymers - low cost, ease of processing and a range of attractive mechanical characteristics - with the specific, tailorable properties of functional organic molecules. The caveat is that the synthesis of functional polymers is frequently complex and involves many steps, which make...

  9. Biodegradable Polymers

    Directory of Open Access Journals (Sweden)

    Isabelle Vroman

    2009-04-01

    Full Text Available Biodegradable materials are used in packaging, agriculture, medicine and other areas. In recent years there has been an increase in interest in biodegradable polymers. Two classes of biodegradable polymers can be distinguished: synthetic or natural polymers. There are polymers produced from feedstocks derived either from petroleum resources (non renewable resources or from biological resources (renewable resources. In general natural polymers offer fewer advantages than synthetic polymers. The following review presents an overview of the different biodegradable polymers that are currently being used and their properties, as well as new developments in their synthesis and applications.

  10. Polymer electronics

    CERN Document Server

    Hsin-Fei, Meng

    2013-01-01

    Polymer semiconductor is the only semiconductor that can be processed in solution. Electronics made by these flexible materials have many advantages such as large-area solution process, low cost, and high performance. Researchers and companies are increasingly dedicating time and money in polymer electronics. This book focuses on the fundamental materials and device physics of polymer electronics. It describes polymer light-emitting diodes, polymer field-effect transistors, organic vertical transistors, polymer solar cells, and many applications based on polymer electronics. The book also disc

  11. Synthetic Metal-Containing Polymers

    Science.gov (United States)

    Manners, Ian

    2004-04-01

    The development of the field of synthetic metal-containing polymers - where metal atoms form an integral part of the main chain or side group structure of a polymer - aims to create new materials which combine the processability of organic polymers with the physical or chemical characteristics associated with the metallic element or complex. This book covers the major developments in the synthesis, properties, and applications of synthetic metal-containing macromolecules, and includes chapters on the preparation and characterization of metal-containing polymers, metallocene-based polymers, rigid-rod organometallic polymers, coordination polymers, polymers containing main group metals, and also covers dendritic and supramolecular systems. The book describes both polymeric materials with metals in the main chain or side group structure and covers the literature up to the end of 2002.

  12. Semiconducting polymer LEDs

    Directory of Open Access Journals (Sweden)

    David Braun

    2002-06-01

    The field of semiconducting polymers has its root in the 1977 discovery of the semiconducting properties of polyacetylene1. This breakthrough earned Alan Heeger, Alan MacDiarmid, and Hideki Shirakawa the 2000 Nobel Prize in Chemistry for ‘the discovery and development of conductive polymers’2–5. Other review articles capture how more than two decades of developments in the physical and chemical understanding of these novel materials has led to new device applications as active and passive electronic and optoelectronic devices ranging from diodes and transistors to polymer LEDs, photodiodes, lasers, and solar cells6–11. Much interest in plastic devices derives from the opportunities to use clever control of polymer structure combined with relatively economical polymer synthesis and processing techniques to obtain simultaneous control over electronic, optical, chemical, and mechanical features5. This article focuses on the advances leading to polymer LEDs12–14.

  13. New developments in thermally stable polymers

    Science.gov (United States)

    Hergenrother, Paul M.

    1991-01-01

    Advances in high-temperature polymers since 1985 are discussed with the emphasis on the chemistry. High-temperature polymers refer to materials that exhibit glass-transition temperatures greater than 200 C and have the chemical structure expected to provide high thermooxidative stability. Specific polymers or series of polymers were selected to show how the chemical structure influences certain properties. Poly(arylene ethers) and polyimides are the two principal families of polymers discussed. Recent work on poly(arylene ethers) has concentrated on incorporating heterocyclic units within the polymer backbone. Recent polyimide work has centered on the synthesis of new polymers from novel monomers, several containing the trifluoromethyl group strategically located on the molecule. Various members in each of these polymer families display a unique combination of properties, heretofore unattainable. Other families of polymers are also briefly discussed with a polymer from an AB maleimidobenzocyclobutene exhibiting an especially attractive combination of properties.

  14. Simultaneous separation/enrichment and detection of trace ciprofloxacin and lomefloxacin in food samples using thermosensitive smart polymers aqueous two-phase flotation system combined with HPLC.

    Science.gov (United States)

    Lu, Yang; Chen, Bo; Yu, Miao; Han, Juan; Wang, Yun; Tan, Zhenjiang; Yan, Yongsheng

    2016-11-01

    Smart polymer aqueous two phase flotation system (SPATPF) is a new separation and enrichment technology that integrated the advantages of the three technologies, i.e., aqueous two phase system, smart polymer and flotation sublation. Ethylene oxide and propylene oxide copolymer (EOPO)-(NH4)2SO4 SPATPF is a pretreatment technique, and it is coupled with high-performance liquid chromatography to analyze the trace ciprofloxacin and lomefloxacin in real food samples. The optimized conditions of experiment were determined in the multi-factor experiment by using response surface methodology. The flotation efficiency of lomefloxacin and ciprofloxacin was 94.50% and 98.23% under the optimized conditions. The recycling experimentsshowed that the smart polymer EOPO could use repeatedly, which will reduce the cost in the future application. PMID:27211613

  15. Photoaddressable Polymers

    Science.gov (United States)

    Bieringer, T.

    Polymers are the perfect materials for a variety of applications in almost every field of technical as well as human life. Because of their macromolecular architecture there are a lot of degrees of freedom in the synthesis of polymers. Owing to the change of their functional composition, they can be tailored even for quite difficult demands. Since a whole industry deals with the processing of polymers, cheap production lines have been developed for almost every polymer. This is the reason why not only the molecular composition but even the price of polymers has been optimized. Therefore these materials can be considered as encouraging components even in highly sophisticated areas of applications.

  16. Integration of active and passive polymer optics

    DEFF Research Database (Denmark)

    Christiansen, Mads Brøkner; Schøler, Mikkel; Kristensen, Anders

    2007-01-01

    We demonstrate a wafer scale fabrication process for integration of active and passive polymer optics: Polymer DFB lasers and waveguides. Polymer dye DFB lasers are fabricated by combined nanoimprint and photolithography (CNP). The CNP fabrication relies on an UV transparent stamp with nm sized...

  17. Polymer Chemistry

    Science.gov (United States)

    Williams, Martha; Roberson, Luke; Caraccio, Anne

    2010-01-01

    This viewgraph presentation describes new technologies in polymer and material chemistry that benefits NASA programs and missions. The topics include: 1) What are Polymers?; 2) History of Polymer Chemistry; 3) Composites/Materials Development at KSC; 4) Why Wiring; 5) Next Generation Wiring Materials; 6) Wire System Materials and Integration; 7) Self-Healing Wire Repair; 8) Smart Wiring Summary; 9) Fire and Polymers; 10) Aerogel Technology; 11) Aerogel Composites; 12) Aerogels for Oil Remediation; 13) KSC's Solution; 14) Chemochromic Hydrogen Sensors; 15) STS-130 and 131 Operations; 16) HyperPigment; 17) Antimicrobial Materials; 18) Conductive Inks Formulations for Multiple Applications; and 19) Testing and Processing Equipment.

  18. Supramolecular control over thermoresponsive polymers

    OpenAIRE

    Victor R. de la Rosa; Patrice Woisel; Richard Hoogenboom

    2016-01-01

    Thermoresponsive polymers facilitate the development of a wide range of applications in multiple areas spanning from construction or water management to lab-on-a-chip technologies and biomedical sciences. The combination of thermoresponsive polymers with supramolecular chemistry, inspired by the molecular mechanisms behind natural systems, is resulting in adaptive and smart materials with unprecedented properties. This work reviews the past advances on the combination of this young field of r...

  19. Polymers & People

    Science.gov (United States)

    Lentz, Linda; Robinson, Thomas; Martin, Elizabeth; Miller, Mary; Ashburn, Norma

    2004-01-01

    Each Tuesday during the fall of 2002, teams of high school students from three South Carolina counties conducted a four-hour polymer institute for their peers. In less than two months, over 300 students visited the Charleston County Public Library in Charleston, South Carolina, to explore DNA, nylon, rubber, gluep, and other polymers. Teams of…

  20. Polymer Informatics

    Science.gov (United States)

    Adams, Nico

    Polymers are arguably the most important set of materials in common use. The increasing adoption of both combinatorial as well as high-throughput approaches, coupled with an increasing amount of interdisciplinarity, has wrought tremendous change in the field of polymer science. Yet the informatics tools required to support and further enhance these changes are almost completely absent. In the first part of the chapter, a critical analysis of the challenges facing modern polymer informatics is provided. It is argued, that most of the problems facing the field today are rooted in the current scholarly communication process and the way in which chemists and polymer scientists handle and publish data. Furthermore, the chapter reviews existing modes of representing and communicating polymer information and discusses the impact, which the emergence of semantic technologies will have on the way in which scientific and polymer data is published and transmitted. In the second part, a review of the use of informatics tools for the prediction of polymer properties and in silico design of polymers is offered.

  1. Combination of computational methods, adsorption isotherms and selectivity tests for the conception of a mixed non-covalent-semi-covalent molecularly imprinted polymer of vanillin.

    Science.gov (United States)

    Puzio, Kinga; Delépée, Raphaël; Vidal, Richard; Agrofoglio, Luigi A

    2013-08-01

    A novel molecularly imprinted polymer (MIP) for vanillin was prepared by photo initiated polymerization in dichloromethane using a mixed semi-covalent and non-covalent imprinting strategy. Taking polymerisable syringaldehyde as "dummy" template, acrylamide was chosen as functional monomer on B3LYP/6-31+G(d,p) density functional theory computational method basis with counterpoise. The binding parameters for the recognition of vanillin on imprinted polymers were studied with three different isotherm models (Langmuir, bi-Langmuir and Langmuir-Freundlich) and compared. The results indicate an heterogeneity of binding sites. It was found and proved by DFT calculations that the specific binding of vanillin in the cavities is due to non-covalent interactions of the template with the hydroxyphenyl- and the amide-moieties. The binding geometry of vanillin in the MIP cavity was also modelled. The obtained MIP is highly specific for vanillin (with an imprinting factor of 7.4) and was successfully applied to the extraction of vanillin from vanilla pods, red wine spike with vanillin, natural and artificial vanilla sugar with a recovery of 80%.

  2. Self reinforced polymer-polymer composites

    Directory of Open Access Journals (Sweden)

    M. Bilewicz

    2007-10-01

    Full Text Available Purpose: Purpose of this paper is the applying of new technology in injection moulding technique and investigation of reinforcement of PC as dispersed phase inside PP matrix (Table 1. Second aim of work is enrichment of those composites by nanoclay and analyzing mechanical behaviour of nanocomposites.Design/methodology/approach: According to design of experiments (DOE specimens were injection moulded in the shape of rectangular bars. Additionally advanced technology of melt manipulation inside mold cavity after injection was used. To achieve this purpose Ferromatik Milacron injection moulding machine, equipped with externally controlled mold was used.Findings: Addition of nanoclay clearly presents highly reinforced system, especially for neat matrix. Evenly dispersed PC particles within PP majority show reinforcement as well. Inducement of shear rate in injection moulding radically improved absorption of energy in nanocomposite.Research limitations/implications: Different variation of material composition, such combination with other polymers and use of different reinforcements (flexible or either rigid is required to be checked in the further work.Practical implications: Reinforcement obtained thanks to dispersed phase and nanofillers creates composites with improved mechanical properties.Originality/value: Morphology development reflects on mechanical behaviour. Its manipulation may affect and improve mechanical properties. Use of advanced technologies opens wide range of possibilities in processing of polymer based systems. At present there is limited number of research of processing-structure-properties relationships of polymer-polymer composites and nanocomposites.

  3. Polymers and colloids

    Energy Technology Data Exchange (ETDEWEB)

    Schurtenberger, P. [ETH Zurich, Inst. fuer Polymere, Zurich (Switzerland)

    1996-11-01

    A wealth of structural information from colloid and polymer solutions on a large range of length scales can be obtained using small angle neutron scattering (SANS) experiments. After a general introduction to the field of soft condensed matter, I shall give a few selected examples on how SANS combined with suitable contrast variation schemes can be used to extract information on the size and conformation of polymer coils in solution and in the melt, and on the local structure and flexibility of polymerlike micelles and microemulsions. (author) 8 figs., tabs., 44 refs.

  4. A novel solid-phase microextraction method based on polymer monolith frit combining with high-performance liquid chromatography for determination of aldehydes in biological samples.

    Science.gov (United States)

    Xu, Hui; Wang, Shuyu; Zhang, Ganbing; Huang, Shiqiang; Song, Dandan; Zhou, Yanping; Long, Guangdou

    2011-03-25

    In this work, a polypropylene frit with porous network structure (20 μm pole size) was first utilized as the mould of polymer monolithic material, poly(methacrylic acid-co-ethylene glycol dimethacrylate) (MAA-co-EDMA) monolith was synthesized within channels and macropores of the frit. A simple and sensitive solid-phase microextraction method based on polymer monolith frit coupled with high-performance liquid chromatography (HPLC) was established and applied to analysis of hexanal and heptanal in biological samples (human urine and serum). In the method, small molecule metabolites (aldehydes) in biological samples derivatized with 2,4-dinitrophenylhydrazine (DNPH), and the formed hydrazones were extracted simultaneously on the monolithic frit and thereafter ultrasound-assisted desorbed with acetonitrile as elution solvent. The experimental parameters with regard to polymerization, derivatization and extraction were investigated. Under the optimal conditions, the linearity was in the range of 0.02-5.0 μmol L(-1) (r=0.9994) for both hexanal and heptanal and the limits of detection (S/N=3) were 0.81 nmol L(-1) for hexanal and 0.76 nmol L(-1) for heptanal. The relative standard deviations (RSDs, n=5) were less than 6.5% for the same monolithic frit and less than 8.9% for the different monolithic frits. Satisfactory recoveries ranging from 70.71% to 88.73% were obtained for the urine samples. The method possesses many advantages including simple setup, fast analysis, low cost, sufficient sensitivity, good biological compatibility and less organic solvent consumption. The proposed method is a useful assistant tool in the clinical early diagnosis of lung disease by monitoring aldehyde biomarker candidates in complex biological samples. PMID:21414440

  5. Antithrombogenic Polymer Coating.

    Science.gov (United States)

    Huang, Zhi Heng; McDonald, William F.; Wright, Stacy C.; Taylor, Andrew C.

    2003-01-21

    An article having a non-thrombogenic surface and a process for making the article are disclosed. The article is formed by (i) coating a polymeric substrate with a crosslinked chemical combination of a polymer having at least two amino substituted side chains, a crosslinking agent containing at least two crosslinking functional groups which react with amino groups on the polymer, and a linking agent containing a first functional group which reacts with a third functional group of the crosslinking agent, and (ii) contacting the coating on the substrate with an antithrombogenic agent which covalently bonds to a second functional group of the linking agent. In one example embodiment, the polymer is a polyamide having amino substituted alkyl chains on one side of the polyamide backbone, the crosslinking agent is a phosphine having the general formula (A).sub.3 P wherein A is hydroxyalkyl, the linking agent is a polyhydrazide and the antithrombogenic agent is heparin.

  6. Acoustomechanics of semicrystalline polymers

    Directory of Open Access Journals (Sweden)

    Fengxian Xin

    2016-01-01

    Full Text Available We develop an acoustomechanical theory for semicrystalline polymers and demonstrate that acoustic radiation force is capable of causing giant deformation in these materials. When a polymer layer is subjected to combined tensile mechanical force in plane and acoustic force (sound pressure through thickness, it becomes initially homogeneously thin but soon inhomogeneous when the two forces reach critical conditions. Critical conditions for such acoustomechanical instability are theoretically determined based on the J2-deformation theory. We demonstrate that pull-in instability can be acoustically triggered even if the in-plane mechanical force is fixed. Bifurcation in the critical condition for acoustomechanical instability occurs when the polymer exhibits sufficiently large hardening. The findings of this study enable reliability design of novel acoustic actuated devices.

  7. Polymer compositions, polymer films and methods and precursors for forming same

    Science.gov (United States)

    Klaehn, John R; Peterson, Eric S; Orme, Christopher J

    2013-09-24

    Stable, high performance polymer compositions including polybenzimidazole (PBI) and a melamine-formaldehyde polymer, such as methylated, poly(melamine-co-formaldehyde), for forming structures such as films, fibers and bulky structures. The polymer compositions may be formed by combining polybenzimidazole with the melamine-formaldehyde polymer to form a precursor. The polybenzimidazole may be reacted and/or intertwined with the melamine-formaldehyde polymer to form the polymer composition. For example, a stable, free-standing film having a thickness of, for example, between about 5 .mu.m and about 30 .mu.m may be formed from the polymer composition. Such films may be used as gas separation membranes and may be submerged into water for extended periods without crazing and cracking. The polymer composition may also be used as a coating on substrates, such as metal and ceramics, or may be used for spinning fibers. Precursors for forming such polymer compositions are also disclosed.

  8. Tumor hypoxia, the Warburg effect, and multidrug resistance: Modulation of hypoxia induced MDR using EGFR-targeted polymer blend nanocarriers for combination paclitaxel/lonidamine therapy

    Science.gov (United States)

    Jabr-Milane, Lara Scheherazade

    Multi-drug resistant (MDR) cancer is a significant clinical obstacle and is often implicated in cases of recurrent, non-responsive disease. The biological focus of this work is to explore the relationship between the hypoxic microenvironment of a tumor, the development of MDR, and the energetic profile characteristic of the Warburg effect (aerobic glycolysis). The therapeutic aim of this research is to develop an EGFR-targeted nanocarrier system for combination (paclitaxel/lonidamine) therapy for the treatment of MDR cancer. The stability of the nanocarrier formulation was validated in vitro and the system was characterized for drug release kinetics, size, surface modification, and EGFR-targeting ability. An orthotopic animal model of hypoxic, MDR breast cancer was developed for the pre-clinical evaluation of this system. The EGFR-targeted nanoparticles loaded with lonidamine and paclitaxel demonstrated superior pharmacokinetic parameters relative to non-targeted nanoparticles and drug solution. Combination therapy with lonidamine and paclitaxel, in solution and EGFR-targeted nanoparticle form, was more effective at suppressing tumor growth than single agent treatment. However, combination therapy with EGFR-targeted nanoparticles was less toxic than treatment with drug solution. Combination therapy did change the MDR and hypoxic character of the tumors as demonstrated by a decrease in marker proteins. This EGFR-targeted combination nanocarrier therapy has the potential to make the successful treatment of MDR a clinical reality.

  9. System Applies Polymer Powder To Filament Tow

    Science.gov (United States)

    Baucom, Robert M.; Snoha, John J.; Marchello, Joseph M.

    1993-01-01

    Polymer powder applied uniformly and in continuous manner. Powder-coating system applies dry polymer powder to continuous fiber tow. Unique filament-spreading technique, combined with precise control of tension on fibers in system, ensures uniform application of polymer powder to web of spread filaments. Fiber tows impregnated with dry polymer powders ("towpregs") produced for preform-weaving and composite-material-molding applications. System and process valuable to prepreg industry, for production of flexible filament-windable tows and high-temperature polymer prepregs.

  10. Conducting polymer 3D microelectrodes

    DEFF Research Database (Denmark)

    Sasso, Luigi; Vazquez, Patricia; Vedarethinam, Indumathi;

    2010-01-01

    Conducting polymer 3D microelectrodes have been fabricated for possible future neurological applications. A combination of micro-fabrication techniques and chemical polymerization methods has been used to create pillar electrodes in polyaniline and polypyrrole. The thin polymer films obtained...... showed uniformity and good adhesion to both horizontal and vertical surfaces. Electrodes in combination with metal/conducting polymer materials have been characterized by cyclic voltammetry and the presence of the conducting polymer film has shown to increase the electrochemical activity when compared...... with electrodes coated with only metal. An electrochemical characterization of gold/polypyrrole electrodes showed exceptional electrochemical behavior and activity. PC12 cells were finally cultured on the investigated materials as a preliminary biocompatibility assessment. These results show that the described...

  11. Conducting Polymer 3D Microelectrodes

    Directory of Open Access Journals (Sweden)

    Jenny Emnéus

    2010-12-01

    Full Text Available Conducting polymer 3D microelectrodes have been fabricated for possible future neurological applications. A combination of micro-fabrication techniques and chemical polymerization methods has been used to create pillar electrodes in polyaniline and polypyrrole. The thin polymer films obtained showed uniformity and good adhesion to both horizontal and vertical surfaces. Electrodes in combination with metal/conducting polymer materials have been characterized by cyclic voltammetry and the presence of the conducting polymer film has shown to increase the electrochemical activity when compared with electrodes coated with only metal. An electrochemical characterization of gold/polypyrrole electrodes showed exceptional electrochemical behavior and activity. PC12 cells were finally cultured on the investigated materials as a preliminary biocompatibility assessment. These results show that the described electrodes are possibly suitable for future in-vitro neurological measurements.

  12. POLYMERS BEYOND THE YEAR 2000

    Institute of Scientific and Technical Information of China (English)

    Ingolf Buethe

    2000-01-01

    At the turn of the century, the global polymer industry is undergoing the most rapid and dramatic changes in its history. Emerging markets, particularly in Asia, and their polymer consumption are catching up with other parts of the world,creating new business opportunities. Economy of scale, combined with optimized logistic concepts, is becoming a key economic success factor, thus forcing smaller suppliers out of business and creating a major hurdle for newcomers and the introduction of new products. Globalization of polymer customers and cost pressure lead to a consolidation of suppliers and products. Today standard thermoplastics have a dominant position in the market and they will retain this position in future.Engineering thermoplastics are facing growing competition due to the increased efficiency of standard polymers. This leads to a displacement process where standard polymers substitute engineering thermoplastics. Simultaneously engineering polymers are pushing into new markets or applications or displacing materials like glass, wood or metal. The recent history and future trends have a strong impact on R&D activity in the polymer industry. Competition on a global scale and increasing cost pressure are turning innovation into an essential precondition of commercial success, thus determining the objectives of industrial polymer research and development.

  13. Intraspinal transplantation of motoneuron-like cell combined with delivery of polymer-based glial cell line-derived neurotrophic factor for repair of spinal cord contusion injury

    Institute of Scientific and Technical Information of China (English)

    Alireza Abdanipour; Taki Tiraihi; Taher Taheri

    2014-01-01

    To evaluate the effects of glial cell line-derived neurotrophic factor transplantation combined with adipose-derived stem cells-transdifferentiated motoneuron delivery on spinal cord con-tusion injury, we developed rat models of spinal cord contusion injury, 7 days later, injected adipose-derived stem cells-transdifferentiated motoneurons into the epicenter, rostral and caudal regions of the impact site and simultaneously transplanted glial cell line-derived neuro-trophic factor-gelfoam complex into the myelin sheath. Motoneuron-like cell transplantation combined with glial cell line-derived neurotrophic factor delivery reduced cavity formations and increased cell density in the transplantation site. The combined therapy exhibited superior promoting effects on recovery of motor function to transplantation of glial cell line-derived neurotrophic factor, adipose-derived stem cells or motoneurons alone. These ifndings suggest that motoneuron-like cell transplantation combined with glial cell line-derived neurotrophic factor delivery holds a great promise for repair of spinal cord injury.

  14. Selective molecularly imprinted polymer combined with restricted access material for in-tube SPME/UHPLC-MS/MS of parabens in breast milk samples.

    Science.gov (United States)

    Souza, Israel D; Melo, Lidervan P; Jardim, Isabel C S F; Monteiro, Juliana C S; Nakano, Ana Marcia S; Queiroz, Maria Eugênia C

    2016-08-17

    A new molecularly imprinted polymer modified with restricted access material (a hydrophilic external layer), (MIP-RAM) was synthesized via polymerization in situ in an open fused silica capillary. This stationary phase was used as sorbent for in-tube solid phase microextraction (in-tube SPME) to determine parabens in breast milk samples by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Scanning electron micrographs (SEM) illustrate MIP surface modification after glycerol dimethacrylate (hydrophilic monomer) incorporation. The interaction between parabens and MIP-RAM was investigated by Fourier-transform infrared (FTIR) spectroscopy. The Scatchard plot for MIP-RAM presented two linear parts with different slopes, illustrating binding sites with high- and low-affinity. Endogenous compounds exclusion from the MIP-RAM capillary was demonstrated by in-tube SPME/LC-UV assays carried out with blank milk samples. The in-tube SPME/UHPLC-MS/MS method presented linear range from 10 ng mL(-1) (LLOQ) to 400 ng mL(-1) with coefficients of determination higher than 0.99, inter-assay precision with coefficient of variation (CV) values ranging from 2 to 15%, and inter-assay accuracy with relative standard deviation (RSD) values ranging from -1% to 19%. Analytical validation parameters attested that in-tube SPME/UHPLC-MS/MS is an appropriate method to determine parabens in human milk samples to assess human exposure to these compounds. Analysis of breast milk samples from lactating women demonstrated that the proposed method is effective. PMID:27286769

  15. Conducting Polymers: Emerging Commercial Materials

    OpenAIRE

    Kumar, N; S. R. Vadera; Jeevan Singh; Das, G.; S. C. Negi; Aparna, P.; Tuli, A

    1996-01-01

    Conducting polymers are materials of recent origin. They are obtained by polymerisation of simple organic monomers and doping with electron acceptor or donor species and show conductivity ranging from that of a semiconductor to that of metal. These materials are now available with unique electronic and optical properties of metals and semiconductors in combination with the attractive mechanical and processable advantages of polymers. The field has progressed to a level of maturity cons...

  16. Mechanisms of proton conductance in polymer electrolyte membranes

    DEFF Research Database (Denmark)

    Eikerling, M.; Kornyshev, A. A.; Kuznetsov, A. M.;

    2001-01-01

    We provide a phenomenological description of proton conductance in polymer electrolyte membranes, based on contemporary views of proton transfer processes in condensed media and a model for heterogeneous polymer electrolyte membrane structure. The description combines the proton transfer events i...

  17. Polymer-Graphene Nanocomposite Materials for Electrochemical Biosensing.

    Science.gov (United States)

    Sobolewski, Peter; Piwowarczyk, Magdalena; Fray, Mirosława El

    2016-07-01

    Biosensing is an important and rapidly developing field, with numerous potential applications in health care, food processing, and environmental control. Polymer-graphene nanocomposites aim to leverage the unique, attractive properties of graphene by combining them with those of a polymer matrix. Molecular imprinted polymers, in particular, offer the promise of artificial biorecognition elements. A variety of polymers, including intrinsically conducting polymers (polyaniline, polypyrrole), bio-based polymers (chitosan, polycatechols), and polycationic polymers (poly(diallyldimethylammonium chloride), polyethyleneimine), have been utilized as matrices for graphene-based nanofillers, yielding sensitive biosensors for various biomolecules, such as proteins, nucleic acids, and small molecules. PMID:27188816

  18. Engineering Polymer Informatics

    OpenAIRE

    Adams, Nico; Ryder, Jennifer; Jessop, David M; Corbett, Peter; Murray-Rust, Peter

    2007-01-01

    The poster describes a strategy of for the development of polymer informatics. In particular, the development of polymer markup language, a polymer ontology and natural language processing tools for polymer literature.

  19. Polymer Materials

    Institute of Scientific and Technical Information of China (English)

    Charles C. Han; DONG Jinyong; NIU Hui; CHENG He; HUANG Ye; ZHENG Jianfen; XU Shanshan

    2011-01-01

    @@ Since the second half of the 20th century, polymer materials have already become an essential part of our daily life.The use of polymeric materials has already exceeded that of metals and ceramics in terms of volume and is intimately connected to our clothing, food, household use, transportation, and medical needs.Meanwhile it also brought some recycle and environmental problems.In the 21 st century, human beings are facing ever increasing challenges on environmental protection, energy shortage, and health-medical problems, which have made even higher demand on polymer materials due to its light weight, flexibility and high functionality.

  20. Polymer electronics

    CERN Document Server

    Geoghegan, Mark

    2013-01-01

    Polymer electronics is the science behind many important new developments in technology, such as the flexible electronic display (e-ink) and many new developments in transistor technology. Solar cells, light-emitting diodes, and transistors are all areas where plastic electronics is likely to, or is already having, a serious impact on our daily lives. With polymer transistors and light-emitting diodes now being commercialised, there is a clear need for a pedagogic text thatdiscusses the subject in a clear and concise fashion suitable for senior undergraduate and graduate students. The content

  1. Biodegradable Polyphosphazene Based Peptide-Polymer Hybrids

    Directory of Open Access Journals (Sweden)

    Anne Linhardt

    2016-04-01

    Full Text Available A novel series of peptide based hybrid polymers designed to undergo enzymatic degradation is presented, via macrosubstitution of a polyphosphazene backbone with the tetrapeptide Gly-Phe-Leu-Gly. Further co-substitution of the hybrid polymers with hydrophilic polyalkylene oxide Jeffamine M-1000 leads to water soluble and biodegradable hybrid polymers. Detailed degradation studies, via 31P NMR spectroscopy, dynamic light scattering and field flow fractionation show the polymers degrade via a combination of enzymatic, as well as hydrolytic pathways. The peptide sequence was chosen due to its known property to undergo lysosomal degradation; hence, these degradable, water soluble polymers could be of significant interest for the use as polymer therapeutics. In this context, we investigated conjugation of the immune response modifier imiquimod to the polymers via the tetrapeptide and report the self-assembly behavior of the conjugate, as well as its enzymatically triggered drug release behavior.

  2. Polymer Science.

    Science.gov (United States)

    Frank, Curtis W.

    1979-01-01

    Described is a series of four graduate level courses in polymer science, offered or currently in preparation, at Stanford University. Course descriptions and a list of required and recommended texts are included. Detailed course outlines for two of the courses are presented. (BT)

  3. Polymer physics

    CERN Document Server

    Gedde, Ulf W

    1999-01-01

    This book is the result of my teaching efforts during the last ten years at the Royal Institute of Technology. The purpose is to present the subject of polymer physics for undergraduate and graduate students, to focus the fundamental aspects of the subject and to show the link between experiments and theory. The intention is not to present a compilation of the currently available literature on the subject. Very few reference citations have thus been made. Each chapter has essentially the same structure: starling with an introduction, continuing with the actual subject, summarizing the chapter in 30D-500 words, and finally presenting problems and a list of relevant references for the reader. The solutions to the problems presented in Chapters 1-12 are given in Chapter 13. The theme of the book is essentially polymer science, with the exclusion of that part dealing directly with chemical reactions. The fundamentals in polymer science, including some basic polymer chemistry, are presented as an introduction in t...

  4. The Plasma Chemistry of Polymer Surfaces

    CERN Document Server

    Friedrich, Jö

    2012-01-01

    This book illustrates plasma properties, polymer characteristics, surface specifics, and how to purposefully combine plasma and polymer chemistry. In so doing, it covers plasma polymerization, surface functionalization, etching, crosslinking, and deposition of monotype functional-group-bearing plasma polymers. It explains different techniques and plasma types, such as pressure-pulsed, remote, low-wattage plasmas and plasma polymerization in liquids. Finally, among the numerous applications discussed are plasmas for chemical synthesis, industrial processes or the modification of membranes and p

  5. Synthesis and characterization of polymer matrix composite material with combination of ZnO filler and nata de coco fiber as a candidate of semiconductor material

    Science.gov (United States)

    Saputra, Asep Handaya; Anindita, Hana Nabila

    2015-12-01

    Synthesis of semiconductor composite using acrylic matrix filled with ZnO and nata de coco fiber has been conducted in this research. The purpose of this research is to obtain semiconductor composite material that has a good mechanical strength and thermal resistance. In situ polymerization method is used in this research and the composites are ready to be characterized after 12 hours. The main parameter that is characterized is the electric conductivity of the composite. Additional parameters are also characterized such as composite's elastic modulus and glass transition temperature. The composites that has been made in this research can be classified as semiconductor material because the conductivity is in the range of 10-8-103 S/cm. In general the addition of ZnO and nata de coco filler can increase the conductivity of the composite. The highest semiconductor characteristic in acrylic/ZnO composite is obtained from 30% volume filler that reach 3.4 x 10-7 S/cm. Similar with acrylic/ZnO composite, in acrylic/nata de coco fiber composite the highest semiconductor characteristic is also obtained from 30% volume filler that reach 1.15 x 10-7 S/cm. Combination of 20% volume of ZnO, 10% volume of nata de coco, and 70% volume of acrylic resulting in composite with electric conductivity of 1.92 x 10-7 S/cm. In addition, combination of ZnO and nata de coco fiber as filler in composite can also improve the characteristic of composite where composite with 20% volume of ZnO filler and 10% volume of nata de coco fiber resulting in composite with elastic modulus of 1.79 GPa and glass transition temperature of 175.73°C which is higher than those in acrylic/ZnO composite.

  6. Conducting Polymers: Emerging Commercial Materials

    Directory of Open Access Journals (Sweden)

    N. Kumar

    1996-04-01

    Full Text Available Conducting polymers are materials of recent origin. They are obtained by polymerisation of simple organic monomers and doping with electron acceptor or donor species and show conductivity ranging from that of a semiconductor to that of metal. These materials are now available with unique electronic and optical properties of metals and semiconductors in combination with the attractive mechanical and processable advantages of polymers. The field has progressed to a level of maturity consistent with a new set of opportunities to develop Wide range of applications based upon conducting polymers as materials for industrial products.Examples include: static charge dissipation, EMI shielding, flexible light emitting diodes, transparent electrodes, batteries, gas sensors, gas separators, etc. Many of the conducting polymers and devices based on them are now available commercially.

  7. Conductive polymer-based material

    Science.gov (United States)

    McDonald, William F.; Koren, Amy B.; Dourado, Sunil K.; Dulebohn, Joel I.; Hanchar, Robert J.

    2007-04-17

    Disclosed are polymer-based coatings and materials comprising (i) a polymeric composition including a polymer having side chains along a backbone forming the polymer, at least two of the side chains being substituted with a heteroatom selected from oxygen, nitrogen, sulfur, and phosphorus and combinations thereof; and (ii) a plurality of metal species distributed within the polymer. At least a portion of the heteroatoms may form part of a chelation complex with some or all of the metal species. In many embodiments, the metal species are present in a sufficient concentration to provide a conductive material, e.g., as a conductive coating on a substrate. The conductive materials may be useful as the thin film conducting or semi-conducting layers in organic electronic devices such as organic electroluminescent devices and organic thin film transistors.

  8. Photogenerating work from polymers

    Directory of Open Access Journals (Sweden)

    Hilmar Koerner

    2008-07-01

    Full Text Available The ability to control the creation of mechanical work remotely, with high speed and spatial precision, over long distances, offers many intriguing possibilities. Recent developments in photoresponsive polymers and nanocomposite concepts are at the heart of these future devices. Whether driving direct conformational changes, initiating reversible chemical reactions to release stored strain, or converting a photon to a local temperature increase, combinations of photoactive units, nanoparticles, ordered mesophases, and polymeric networks are providing an expansive array of photoresponsive polymer options for mechanical devices. Framing the typically geometry-specific observations into an applied engineering vocabulary will ultimately define the role of these materials in future actuator applications, ranging from microfluidic valves in medical devices to optically controlled mirrors in displays.

  9. How do polymers degrade?

    Science.gov (United States)

    Lyu, Suping

    2011-03-01

    Materials derived from agricultural products such as cellulose, starch, polylactide, etc. are more sustainable and environmentally benign than those derived from petroleum. However, applications of these polymers are limited by their processing properties, chemical and thermal stabilities. For example, polyethylene terephthalate fabrics last for many years under normal use conditions, but polylactide fabrics cannot due to chemical degradation. There are two primary mechanisms through which these polymers degrade: via hydrolysis and via oxidation. Both of these two mechanisms are related to combined factors such as monomer chemistry, chain configuration, chain mobility, crystallinity, and permeation to water and oxygen, and product geometry. In this talk, we will discuss how these materials degrade and how the degradation depends on these factors under application conditions. Both experimental studies and mathematical modeling will be presented.

  10. Fabrication of silicon molds for polymer optics

    DEFF Research Database (Denmark)

    Nilsson, Daniel; Jensen, Søren; Menon, Aric Kumaran

    2003-01-01

    A silicon mold used for structuring polymer microcavities for optical applications is fabricated, using a combination of DRIE (deep reactive ion etching) and anisotropic chemical wet etching with KOH + IPA. For polymer optical microcavities, low surface roughness and vertical sidewalls are often...

  11. Simple numerical techniques for mesoscale polymer models

    NARCIS (Netherlands)

    E.A. Koopman

    2014-01-01

    There exist various numerical techniques for modeling polymer behavior on small time and length scales. This work introduces some new techniques in this field, and shows novel new combinations of existing techniques. Among the new techniques are multiple new thermostats, a way of modeling polymers i

  12. Nanocomposites Derived from Polymers and Inorganic Nanoparticles

    Directory of Open Access Journals (Sweden)

    In-Yup Jeon

    2010-06-01

    Full Text Available Polymers are considered to be good hosting matrices for composite materials because they can easily be tailored to yield a variety of bulk physical properties. Moreover, organic polymers generally have long-term stability and good processability. Inorganic nanoparticles possess outstanding optical, catalytic, electronic and magnetic properties, which are significantly different their bulk states. By combining the attractive functionalities of both components, nanocomposites derived from organic polymers and inorganic nanoparticles are expected to display synergistically improved properties. The potential applications of the resultant nanocomposites are various, e.g. automotive, aerospace, opto-electronics, etc. Here, we review recent progress in polymer-based inorganic nanoparticle composites.

  13. Novel Polymer Microfluidics Technology for In Situ Planetary Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Los Gatos Research proposes to develop a novel microfluidic device that combines rigid monolithic porous polymer based micro-capillary electrochromatography...

  14. Characterizing the Polymer:Fullerene Intermolecular Interactions

    KAUST Repository

    Sweetnam, Sean

    2016-02-02

    Polymer:fullerene solar cells depend heavily on the electronic coupling of the polymer and fullerene molecular species from which they are composed. The intermolecular interaction between the polymer and fullerene tends to be strong in efficient photovoltaic systems, as evidenced by efficient charge transfer processes and by large changes in the energetics of the polymer and fullerene when they are molecularly mixed. Despite the clear presence of these strong intermolecular interactions between the polymer and fullerene, there is not a consensus on the nature of these interactions. In this work, we use a combination of Raman spectroscopy, charge transfer state absorption, and density functional theory calculations to show that the intermolecular interactions do not appear to be caused by ground state charge transfer between the polymer and fullerene. We conclude that these intermolecular interactions are primarily van der Waals in nature. © 2016 American Chemical Society.

  15. Functional Films from Silica/Polymer Nanoparticles

    Directory of Open Access Journals (Sweden)

    Tânia Ribeiro

    2014-05-01

    Full Text Available High performance functional coatings, based on hybrid organic/inorganic materials, are being developed to combine the polymer flexibility and ease of processing with the mechanical properties and versatility of inorganic materials. By incorporating silica nanoparticles (SiNPs in the polymeric matrices, it is possible to obtain hybrid polymer films with increased tensile strength and impact resistance, without decreasing the flexural properties of the polymer matrix. The SiNPs can further be used as carriers to impart other functionalities (optical, etc. to the hybrid films. By using polymer-coated SiNPs, it is possible to reduce particle aggregation in the films and, thus, achieve more homogeneous distributions of the inorganic components and, therefore, better properties. On the other hand, by coating polymer particles with silica, one can create hierarchically structured materials, for example to obtain superhydrophobic coatings. In this review, we will cover the latest developments in films prepared from hybrid polymer/silica functional systems.

  16. Ultrafiltration of a polymer-electrolyte mixture

    NARCIS (Netherlands)

    Vonk, P; Noordman, T.R; Schippers, D; Tilstra, B; Wesselingh, J.A

    1997-01-01

    We present a mathematical model to describe the ultrafiltration behaviour of polymer-electrolyte mixtures. The model combines the proper thermodynamic forces (pressure, chemical potential and electrical potential differences) with multicomponent diffusion theory. The model is verified with experimen

  17. Polymer nanocomposites reinforced with montmorillonite

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2012-01-01

    Full Text Available Purpose: Light microscope with polarized light has been used for observation layered zone, visible thanks to polarization of the light, inside polymer-polymer composites and nanocomposites Aim of work has been concentrated on investigation of nanocomposites as promising engineering materials, basing on composition of polypropylene and montmorillonite as reinforcement in the shape of nanoparticles of 2:1 silicate.Design/methodology/approach: Conventional and non-conventional injection molding process has been used for obtaining nanocomposites. In non-conventional process has been used the special mold for inducing the shear rates, additionally equipped with external computer to control melt manipulation of solidifying polymer inside mold cavityFindings: Highly developed structure consisted of multilayer zone between skin and core mainly responsible for reinforcement and improvement of fracture toughness of polymer composites and nanocompositesResearch limitations/implications: Nanocomposites of polymer blends and montmorillonite were moulded by direct injection moulding according to melt temperature and stroke time-number combination included in design of experiments.Practical implications: Application of special injection moulding technique provides to structure development and gives possibility to create multilayer zone, which strengthen material. Besides strengthening obtaining of such nanocomposites is cheap thanks to application of low cost injection moulding technique and not expensive polyolefines with developed structure, without using additional fillers (e.g. compatybilizers.Originality/value: Very wide application of polymer composites and nanocomposites as engineering materials used for various industries like building engineering, automotive and aerospace

  18. Polymers for Micropollutants Removal from Wastewater

    OpenAIRE

    M. F. Mohd Amin

    2015-01-01

    The presence of micropollutants, especially pharmaceuticals, in wastewater has become a significant concern to both the water treatment industry as well as consumers. A new method of treatment was developed to curb this problem. The use of polymers as flocculants and combining them with materials helped to reduce the concentration of these pharmaceuticals in the final wastewater effluent. The potential usage of polymers and the combination with particles and conventional adsorbents towards re...

  19. Transparent and conductive polymer layers by gas plasma techniques

    OpenAIRE

    Groenewoud, Lucas Marinus Hendrikus

    2000-01-01

    Polymers are widely used in a great number of applications because of their general properties such as low density, low cost, and processability. If these properties could be combined with electrical conductivity, this would open up the way to desirable applications such as flexible LCD’s and polymer electronics (cheap, lightweight, etc.). For applications requiring electrical conductivity, the choice of a suitable polymer is limited to polymers with a conjugated chemical structure such as po...

  20. Effects of combination of superabsorbent polymers (SAP) with nitrogen fertilizer on growth and photosynthesis of pepper plants%保水剂与氮肥结合对辣椒生长及光合作用的影响

    Institute of Scientific and Technical Information of China (English)

    徐刚; 韩玉玲; 高文瑞; 李德翠; 韩冰; 孙艳军

    2012-01-01

    Pepper variety Chaoyue No. 5 was selected as material to study the effects of combination of superabsorbent polymers (SAP) with nitrogen fertilizer on growth and photosynthesis of pepper during flowering using SAP absorbing carbamide. The combination of SAP with nitrogen fertiliser significantly increased the height, stem diameter, fresh weight, dry weight and chlorophyll content of leaves, as well as the net photosynthetic rate (Pn), intercellular CO2 concentration (Ci) , stomatal conduct (Gs) and transpiration rate (Tr) , but decreased the stomata limitation (Ls) and water efficiency ( WUE) under the same nitrogen application condition. The growth, chlorophyll content, Pn, Ci, Gs and Tr of pepper with the treatment of SAP combining nitrogen of 0. 75 times as many as standard application level were significantly higher than those with the treatment of applying nitrogen at standard level. It indicated that using SAP to absorb urea increased the fertiliser use efficiency, and reduced the loss of fertilizer.%以辣椒品种超越5号为试验材料,采用保水剂吸收尿素溶液的方法,探讨了保水剂与氮肥结合对辣椒开花坐果期植株生长及光合特性的影响.结果表明:在相同的氮肥条件下,保水剂与氮肥结合提高了植株的株高、茎粗、干鲜重、叶绿素含量以及净光合速率(Pn)、胞间CO2浓度(Ci)、气孔导度(Gs)和蒸腾速率(Tr)等光合参数,降低了气孔限制值(Ls)和水分利用效率(WUE);同时保水剂+0.75倍标准氮肥用量处理的叶片生长量、叶绿素含量、Pn、Ci、Gs和Tr都显著高子1倍标准氮肥用量的处理,表明采用保水剂吸收尿素溶液的方式能够提高肥料利用率,降低肥料损失.

  1. FTIR Drug-Polymer Interactions Studies of Perindopril Erbumine

    International Nuclear Information System (INIS)

    The present study was carried out to prepare different combinations of Perindopril Erbumine with different polymers like Hydroxy propyl methyl cellulose, Hydroxy propyl methyl cellulose K4M, Hydroxy propyl methyl cellulose K15M, Xanthan gum and Ethyl cellulose, thereby to determine any possible interactions between Perindopril erbumine and polymers. The analytical technique Fourier Transform Infrared (FTIR) spectroscopy was used to take spectra of individual drug, polymers and combination of drug with polymers. The results were analyzed to find out any interactions of Perindopril erbumine and polymers. From this study it was concluded that there were no any significant changes in characteristic peaks of drug after combinations with polymers which indicated no interaction between Perindopril erbumine and polymers. (author)

  2. Modeling of Polymer Erosion

    OpenAIRE

    Göpferich, Achim; Langer, Robert S.

    1993-01-01

    The erosion of bioerodible polymers depends on many factors including the polymer chain length, bond cleavage velocity, swellability, crystallinity, and water diffusivity in the polymer matrix. This multitude of parameters makes modeling of erosion difficult. Only a few models exist that describe morphological changes of polymers during erosion qualitatively. In the present approach the polymer matrix was represented as the sum of small individual polymer matrix parts. The factors that determ...

  3. Discussion of Organic Combination with Theory and Practice of Polymer Chemistry Course Based on PLA Preparation%基于PLA制备的高分子化学理论与实践的有机结合

    Institute of Scientific and Technical Information of China (English)

    朱久进; 李刚

    2013-01-01

    Polymer chemistry course mainly introduces basic concepts,principles and basic methods of polymerization,and according to the mechanism,polymerization is divided into step polymerization,radical polymerization,radical copolymerization,ionic polymerization and coordination polymerization.To avoid too empty and abstract in the curriculum theory teaching,this paper uses the authors' scientific research as an example,i.e.,the synthesis process of lactic acid as raw material for preparing PLA(polylactic acid),combining with the basic principles of the polymerization reaction in the course of teaching,to discuss the reaction mechanism of linear condensation polymerization,cationic ring-opening polymerization,anionic ring-opening polymerization,coordination polymerization,etc.It integrates theory teaching,scientific research work and actual production together,to achieve a win-win of teaching and learning.%高分子化学课程以基本概念、聚合原理和基本聚合方法为主,按照聚合机理分为逐步聚合、自由基聚合、自由基共聚合、离子聚合和配位聚合.为避免课程理论教学过于空洞和抽象,作者以科研中乳酸为原料制备聚乳酸的合成过程为例,结合课程教学中聚合反应的基本原理,探讨了线性缩聚反应、阳离子开环聚合反应、阴离子开环聚合反应、配位聚合反应等反应机理,将理论教学与科研工作、生产实际相结合,使教与学达到双赢.

  4. Mass Spectrometry in Polymer Chemistry

    CERN Document Server

    Barner-Kowollik, Christopher; Falkenhagen, Jana; Weidner, Steffen

    2011-01-01

    Combining an up-to-date insight into mass-spectrometric polymer analysis beyond MALDI with application details of the instrumentation, this is a balanced and thorough presentation of the most important and widely used mass-spectrometric methods.Written by the world's most proficient experts in the field, the book focuses on the latest developments, covering such technologies and applications as ionization protocols, tandem and liquid chromatography mass spectrometry, gas-phase ion-separation techniques and automated data processing. Chapters on sample preparation, polymer degradation and the u

  5. Polyamide 6 single polymer composites

    Directory of Open Access Journals (Sweden)

    2009-08-01

    Full Text Available Combining the two basic techniques used for the preparation of single polymer composites (SPCs, hot compaction and film stacking, a polyamide 6 (PA 6 single polymer composite was manufactured. The starting materials were PA 6 high tenacity yarn (reinforcement and PA 6 film prepared via melt quenching (matrix, both expected to be the two principal polymorphic modifications of PA 6 and thus differing in their melting temperatures. The prepared single polymer composite is characterized by a layered structure and shows superior mechanical properties due to the good wetting – tensile modulus is improved by 200% and the ultimate tensile strength – by 300–400% as compared to the isotropic matrix film. Improvement of the interfacial adhesion via transreactions promoted by Sb2O3 as a catalyst was also undertaken.

  6. Photochemical stability of π-conjugated polymers for polymer solar cells: a rule of thumb

    DEFF Research Database (Denmark)

    Manceau, Matthieu; Bundgaard, Eva; Carlé, Jon Eggert;

    2011-01-01

    A comparative photochemical stability study of a wide range of π-conjugated polymers relevant to polymer solar cells is presented. The behavior of each material has been investigated under simulated sunlight (1 sun, 1000 W m−2, AM 1.5G) and ambient atmosphere. Degradation was monitored during...... ageing combining UV-visible and infrared spectroscopies. From the comparison of the collected data, the influence of the polymer chemical structure on its stability has been discussed. General rules relative to the polymer structure–stability relationship are proposed....

  7. Reconstruction of Tissue Engineering Skin by Epidermal Cells and Fibroblasts Combined with Modified Polymer of Lactic Acid%皮肤细胞复合改性聚乳酸构建组织工程皮肤

    Institute of Scientific and Technical Information of China (English)

    冯颖; 王宗良; 师铁英; 石毅; 周余来; 颜炜群

    2007-01-01

    目的:探讨以改性聚乳酸为细胞外基质网架构建组织工程皮肤的可行性.方法:采用盐溶法制备机械性能得到部分改进的聚乳酸多孔泡沫网架,向改进的聚乳酸网架接种真皮成纤维细胞和表皮角质形成细胞,以普通聚乳酸支架作为对照,构建组织工程皮肤.体外培养一周,对网架进行形态学观察.主要观察指标:①一般形态观察②组织学观察.结果:复层组织工程皮肤在结构上与正常皮肤相似,具有真皮、表皮双层结构.改性聚乳酸网架上有双层细胞生长,生长的细胞与网架接触,并且在其表面形成较为明显而连续的细胞层.随着培养时间的延长,发生了一系列变化:表皮部分细胞层数逐渐增多,真皮部分细胞也逐渐增多,并向表皮层深入,位于表皮与网架之间.结论:双醛淀粉作为良好的增柔剂在改善聚乳酸网架的机械性能的同时,也具有良好的细胞相容性,不影响细胞的生长增殖和代谢,可以进一步用作组织工程皮肤的支架材料.%Objective: To investigate the applied feasibility of scaffold with modified PLA (Polymer of lactic acid) in tissue engineering. Methods:First, we adopted salting-in method to prepare porous foam scaffold. Then, we reconstructed tissue engineering skin by epidermal cells and fibroblasts combined with modified PLA. On the 14th day of cell culturing in vitro, we was a control. Results:The arfificial skin is composed of epidermis and dermis and similar to natural skin in appearance. The skin consists of fibroblasts and keratinocytes, which are in various proliferation and differentiation stages. Fibroblasts and keratinocytes distribute on the surface of polymer of lactic acid (PLA) and the number of fibroblast and keratinocyte increase. Conclusion:Dialdehyde starches (DAS) not only improve the function of PLA but also have good effects on cells. Moreover, it does not affect the growth and the metabolism of the cells. So it is

  8. Shape memory polymers

    Science.gov (United States)

    Wilson, Thomas S.; Bearinger, Jane P.

    2015-06-09

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxyl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  9. Multicomponent Thermodynamics of Strain-Induced Polymer Crystallization.

    Science.gov (United States)

    Zha, Liyun; Wu, Yixian; Hu, Wenbing

    2016-07-14

    We developed a linear combination of two Flory's melting-point theories, one for stretched and the other for solution polymers, to predict the melting point of stretched solution polymers. The dependences of the melting strains on varying temperatures, polymer volume fractions, and solvent qualities were verified by the onset strains of crystallization in our dynamic Monte Carlo simulations of stretched solution polymers under a constant strain rate. In addition, owing to phase separation before crystallization in a poor solvent, calibration of polymer concentration to the polymer-rich phase appears necessary for the verification. Our results set up a preliminary thermodynamic background for the investigation of the multicomponent effect on strain-induced crystallization of polymers in rubbers and gels as well as on shear-induced crystallization of polymers in solutions and blends. PMID:27337066

  10. Polymer friction Molecular Dynamics

    OpenAIRE

    Sivebæk, Ion Marius; Samoilov, Vladimir N.; Persson, Bo N. J.

    2010-01-01

    We present molecular dynamics friction calculations for confined hydrocarbon solids with molecular lengths from 20 to 1400 carbon atoms. Two cases are considered: a) polymer sliding against a hard substrate, and b) polymer sliding on polymer. In the first setup the shear stresses are relatively independent of molecular length. For polymer sliding on polymer the friction is significantly larger, and dependent on the molecular chain length. In both cases, the shear stresses are proportional to ...

  11. Friction between Polymer Brushes

    OpenAIRE

    Sokoloff, J. B.

    2006-01-01

    By solving the equilibrium equations for a polymer in a neutral polymer brush, the degree of interpenetration of two polymer brushes in contact and near contact is calculated. These results are used to calculate values of the force of static friction in agreement with recent friction measurements for polymer brush lubricated surfaces. It is shown that at sufficiently light loads polymer brush coated surfaces can slide, with the load supported entirely by osmotic pressure, at a sufficiently la...

  12. Biochemical synthesis of water soluble conducting polymers

    Science.gov (United States)

    Bruno, Ferdinando F.; Bernabei, Manuele

    2016-05-01

    An efficient biomimetic route for the synthesis of conducting polymers/copolymers complexed with lignin sulfonate and sodium (polystyrenesulfonate) (SPS) will be presented. This polyelectrolyte assisted PEG-hematin or horseradish peroxidase catalyzed polymerization of pyrrole (PYR), 3,4 ethyldioxithiophene (EDOT) and aniline has provided a route to synthesize water-soluble conducting polymers/copolymers under acidic conditions. The UV-vis, FTIR, conductivity and cyclic voltammetry studies for the polymers/copolymer complex indicated the presence of a thermally stable and electroactive polymers. Moreover, the use of water-soluble templates, used as well as dopants, provided a unique combination of properties such as high electronic conductivity, and processability. These polymers/copolymers are nowadays tested/evaluated for antirust features on airplanes and helicopters. However, other electronic applications, such as photovoltaics, for transparent conductive polyaniline, actuators, for polypyrrole, and antistatic films, for polyEDOT, will be proposed.

  13. Polymer nanocomposites: polymer and particle dynamics

    KAUST Repository

    Kim, Daniel

    2012-01-01

    Polymer nanocomposites containing nanoparticles smaller than the random coil size of their host polymer chains are known to exhibit unique properties, such as lower viscosity and glass transition temperature relative to the neat polymer melt. It has been hypothesized that these unusual properties result from fast diffusion of the nanostructures in the host polymer, which facilitates polymer chain relaxation by constraint release and other processes. In this study, the effects of addition of sterically stabilized inorganic nanoparticles to entangled cis-1,4-polyisoprene and polydimethylsiloxane on the overall rheology of nanocomposites are discussed. In addition, insights about the relaxation of the host polymer chains and transport properties of nanoparticles in entangled polymer nanocomposites are presented. The nanoparticles are found to act as effective plasticizers for their entangled linear hosts, and below a critical, chemistry and molecular-weight dependent particle volume fraction, lead to reduced viscosity, glass transition temperature, number of entanglements, and polymer relaxation time. We also find that the particle motions in the polymer host are hyperdiffusive and at the nanoparticle length scale, the polymer host acts like a simple, ideal fluid and the composites\\' viscosity rises with increasing particle concentration. © 2012 The Royal Society of Chemistry.

  14. Loop polymer brushes from polymer single crystals

    Science.gov (United States)

    Zhou, Tian; Li, Christopher

    2014-03-01

    Loop polymer brushes represent a category of polymer brushes with both chain ends being tethered to a surface or interface with sufficiently high density. Due to this morphological difference, loop brushes exhibit distinct properties compared with traditional polymer brushes with single chain end being tethered. In our study, α, ω-functionalized polycaprolactone (PCL) single crystals were prepared as templates for polymer brush synthesis. By carefully controlling crystallization condition and immobilization, looped polymer brushes were successfully prepared. Comprehensive studies on the morphology and physical properties of these polymer brushes were carried out using Atomic Force Microscopy and FTIR. Advantages of using this method include exclusive loop morphology, high grafting density, controlled tethering sites and tunable loop size.

  15. Metal-containing polymers via electropolymerization.

    Science.gov (United States)

    Friebe, Christian; Hager, Martin D; Winter, Andreas; Schubert, Ulrich S

    2012-01-17

    Electropolymerization represents a suitable and well-established approach for the assembly of polymer structures, in particular with regard to the formation of thin, insoluble films. Utilization of monomers that are functionalized with metal complex units allows the combination of structural and functional benefits of polymers and metal moieties. Since a broad range of both electropolymerizable monomers and metal complexes are available, various structures and, thus, applications are possible. Recent developments in the field of synthesis and potential applications of metal-functionalized polymers obtained via electropolymerization are presented, highlighting the significant advances in this field of research. PMID:22184013

  16. Biological activity of ionene polymers

    Science.gov (United States)

    Rembaum, A.

    1973-01-01

    Ionene polymers are polyammonium salts with positive nitrogens in the backbone, resulting from the polycondensation of diamines with dihalides or from the polycondensation of halo amines. The mechanism of formation of ionene polymers of different structures and their biological activity is reviewed. The antimicrobial and antifungal properties are compared with low molecular weight ammonium salts. Ionenes were found to combine with DNA by means of ionic bonds to yield similar complexes to those obtained with polyamines (spermine and spermidine). They also combine with nerve cell receptors and exercise a more powerful and longer duration ganglionic blocking action than their monomeric analogs. The antiheparin activity of ionenes and the thromboresistance of elastomeric ionene heparin coatings is described. The enhanced biological activity of ionenes as compared with low molecular weight compounds is attributed to a cooperative effect of a large number of positive charges on the polymeric chains.

  17. Waste treatment from polymer composite materials

    OpenAIRE

    Srebrenkoska, Vineta; Capeska Bogtinoska, Dijana

    2012-01-01

    the future. Also, for this type of materials, several regulations put pressure on producers to consider the waste treatment. Waste treatment of polymer composites is more complex compared to recycling of steel and aluminium, since they contain a mixture of materials with a multitude of combinations of fibres and polymer matrixes. In addition, for sandwich constructions there is also core material to consider. In this paper we started with a research of the most important issues in...

  18. Nanocomposites Derived from Polymers and Inorganic Nanoparticles

    OpenAIRE

    In-Yup Jeon; Jong-Beom Baek

    2010-01-01

    Polymers are considered to be good hosting matrices for composite materials because they can easily be tailored to yield a variety of bulk physical properties. Moreover, organic polymers generally have long-term stability and good processability. Inorganic nanoparticles possess outstanding optical, catalytic, electronic and magnetic properties, which are significantly different their bulk states. By combining the attractive functionalities of both components, nanocomposites derived from organ...

  19. Carbon Nanotube-Conducting Polymer Composites Based Solar Cells

    Institute of Scientific and Technical Information of China (English)

    Prakash; R.Somani; M.Umeno

    2007-01-01

    1 Results Combination of carbon nanotubes (CN) with polymers is important for application towards value added composites,solar cells,fuel cells etc.Especially interesting is the combination of CN with π-conjugated polymers because of the potential interaction between the highly delocalized π-electrons of the CN and the π-electrons correlated with the lattice of polymer skeleton.Efficient exciton dissociation due to electron transfer from the photoexcited polymer to CN is of interest for photovoltaic app...

  20. Supramolecular nesting of cyclic polymers

    Science.gov (United States)

    Kondratuk, Dmitry V.; Perdigão, Luís M. A.; Esmail, Ayad M. S.; O'Shea, James N.; Beton, Peter H.; Anderson, Harry L.

    2015-04-01

    Advances in template-directed synthesis make it possible to create artificial molecules with protein-like dimensions, directly from simple components. These synthetic macromolecules have a proclivity for self-organization that is reminiscent of biopolymers. Here, we report the synthesis of monodisperse cyclic porphyrin polymers, with diameters of up to 21 nm (750 C-C bonds). The ratio of the intrinsic viscosities for cyclic and linear topologies is 0.72, indicating that these polymers behave as almost ideal flexible chains in solution. When deposited on gold surfaces, the cyclic polymers display a new mode of two-dimensional supramolecular organization, combining encapsulation and nesting; one nanoring adopts a near-circular conformation, thus allowing a second nanoring to be captured within its perimeter, in a tightly folded conformation. Scanning tunnelling microscopy reveals that nesting occurs in combination with stacking when nanorings are deposited under vacuum, whereas when they are deposited directly from solution under ambient conditions there is stacking or nesting, but not a combination of both.

  1. Polymer Fluid Dynamics.

    Science.gov (United States)

    Bird, R. Byron

    1980-01-01

    Problems in polymer fluid dynamics are described, including development of constitutive equations, rheometry, kinetic theory, flow visualization, heat transfer studies, flows with phase change, two-phase flow, polymer unit operations, and drag reduction. (JN)

  2. Polymer composites containing nanotubes

    Science.gov (United States)

    Bley, Richard A. (Inventor)

    2008-01-01

    The present invention relates to polymer composite materials containing carbon nanotubes, particularly to those containing singled-walled nanotubes. The invention provides a polymer composite comprising one or more base polymers, one or more functionalized m-phenylenevinylene-2,5-disubstituted-p-phenylenevinylene polymers and carbon nanotubes. The invention also relates to functionalized m-phenylenevinylene-2,5-disubstituted-p-phenylenevinylene polymers, particularly to m-phenylenevinylene-2,5-disubstituted-p-phenylenevinylene polymers having side chain functionalization, and more particularly to m-phenylenevinylene-2,5-disubstituted-p-phenylenevinylene polymers having olefin side chains and alkyl epoxy side chains. The invention further relates to methods of making polymer composites comprising carbon nanotubes.

  3. Statistical Investigation of Mechanical Characteristics of Polymer Concrete Using Mixture Design of Experiments

    OpenAIRE

    Daniel Lepădatu; Marinela Bărbuţă

    2007-01-01

    The aim of this paper is to present an approach for developing material models, using a statistical investigation, for analysing the mechanical characteristics of polymer concrete. The experimental studies were realized on polymer concrete prepared of epoxy resin, silica fume and aggregates. The mix combinations were designed based on the mixture design of experiments concept. For each polymer concrete combination the mechanical properties were studied. The results are reported for polymer co...

  4. ENHANCED OIL-RECOVERY EXPERIMENT AFTER POLYMER FLOOD BY COMBINING HORIZONTAL WELL WITH CHEMICAL FLOODINGS%水平井与化学驱结合提高聚驱后采收率实验

    Institute of Scientific and Technical Information of China (English)

    刘平; 李宜强; 李瑞升

    2011-01-01

    为了老油田可采储量进一步挖潜,提高特高含水油田厚油层采收率,开展了水平井聚合物驱后剩余油室内实验,研制了含黏土矿物的三维正韵律物理模型,优选了适合于水平势的化学驱油剂(高浓度聚合物、聚表剂、二元复合体系、三元复合体系),设计了台理的井网模式.实验结果表明,水平井最佳化学驱油剂为二元复合体系,最佳井网模式为水平井一注一采井网.在聚合物驱基础上采收率可再提高17.69个百分点,得到了聚驱后进一步提高采收率的新方法.%In order to further tap the potentials of mature oilfield reserves and enhance the recovery of the thick oil reservoirs for ultra-high watercut oilfield, the lab. Experiments of the remained oil after polymer flooding in a horizontal well are performed; the 3D positive-rhythm physical model, which contains clay minerals, is developed; the chemical oil-flooding agents (including high-concentration polymer, functional polymer, binary and ASP composite systems) are optimized for horizontal wells, and furthermore the reasonable well patterns are designed. The experimental results show that optimal displacing method for the horizontal well is binary (polymer-surfactant) composite system; the optimal well pattern for the horizontal well is composed of one injector and one producer. On the basis of polymer flooding, the oil recovery has been enhanced 17. 69%. In a word, a new approach to further improve oil recovery after polymer flooding is achieved.

  5. Conducting polymers as potential active materials in electrochemical supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Rudge, A.; Davey, J.; Raistrick, I.; Gottesfeld, S. [Los Alamos National Lab., NM (United States); Ferraris, J.P. [Texas Univ., Richardson, TX (United States). Dept. of Chemistry

    1992-12-01

    Electronically,conducting polymers represent an interesting class of materials for use in electrochemical capacitors because of the combination of high capacitive energy density and low materials cost. Three generalized types of electrochemical capacitors can be constructed using conducting polymers as active material, and in the third of these, which utilizes conducting polymers that can be both n- and p-doped, energy densities of up to 40 watt-hours per kilogram of active material on both electrodes have been demonstrated.

  6. Conducting polymers as potential active materials in electrochemical supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Rudge, A.; Davey, J.; Raistrick, I.; Gottesfeld, S. (Los Alamos National Lab., NM (United States)); Ferraris, J.P. (Texas Univ., Richardson, TX (United States). Dept. of Chemistry)

    1992-01-01

    Electronically,conducting polymers represent an interesting class of materials for use in electrochemical capacitors because of the combination of high capacitive energy density and low materials cost. Three generalized types of electrochemical capacitors can be constructed using conducting polymers as active material, and in the third of these, which utilizes conducting polymers that can be both n- and p-doped, energy densities of up to 40 watt-hours per kilogram of active material on both electrodes have been demonstrated.

  7. Nanoporous polymer electrolyte

    Science.gov (United States)

    Elliott, Brian; Nguyen, Vinh

    2012-04-24

    A nanoporous polymer electrolyte and methods for making the polymer electrolyte are disclosed. The polymer electrolyte comprises a crosslinked self-assembly of a polymerizable salt surfactant, wherein the crosslinked self-assembly includes nanopores and wherein the crosslinked self-assembly has a conductivity of at least 1.0.times.10.sup.-6 S/cm at 25.degree. C. The method of making a polymer electrolyte comprises providing a polymerizable salt surfactant. The method further comprises crosslinking the polymerizable salt surfactant to form a nanoporous polymer electrolyte.

  8. Polymer friction Molecular Dynamics

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Samoilov, Vladimir N.; Persson, Bo N. J.

    We present molecular dynamics friction calculations for confined hydrocarbon solids with molecular lengths from 20 to 1400 carbon atoms. Two cases are considered: a) polymer sliding against a hard substrate, and b) polymer sliding on polymer. In the first setup the shear stresses are relatively...... independent of molecular length. For polymer sliding on polymer the friction is significantly larger, and dependent on the molecular chain length. In both cases, the shear stresses are proportional to the squeezing pressure and finite at zero load, indicating an adhesional contribution to the friction force....

  9. Stochastic resonance during a polymer translocation process.

    Science.gov (United States)

    Mondal, Debasish; Muthukumar, M

    2016-04-14

    We have studied the occurrence of stochastic resonance when a flexible polymer chain undergoes a single-file translocation through a nano-pore separating two spherical cavities, under a time-periodic external driving force. The translocation of the chain is controlled by a free energy barrier determined by chain length, pore length, pore-polymer interaction, and confinement inside the donor and receiver cavities. The external driving force is characterized by a frequency and amplitude. By combining the Fokker-Planck formalism for polymer translocation and a two-state model for stochastic resonance, we have derived analytical formulas for criteria for emergence of stochastic resonance during polymer translocation. We show that no stochastic resonance is possible if the free energy barrier for polymer translocation is purely entropic in nature. The polymer chain exhibits stochastic resonance only in the presence of an energy threshold in terms of polymer-pore interactions. Once stochastic resonance is feasible, the chain entropy controls the optimal synchronization conditions significantly. PMID:27083746

  10. Thermoelectric Polymers and their Elastic Aerogels.

    Science.gov (United States)

    Khan, Zia Ullah; Edberg, Jesper; Hamedi, Mahiar Max; Gabrielsson, Roger; Granberg, Hjalmar; Wågberg, Lars; Engquist, Isak; Berggren, Magnus; Crispin, Xavier

    2016-06-01

    Electronically conducting polymers constitute an emerging class of materials for novel electronics, such as printed electronics and flexible electronics. Their properties have been further diversified to introduce elasticity, which has opened new possibility for "stretchable" electronics. Recent discoveries demonstrate that conducting polymers have thermoelectric properties with a low thermal conductivity, as well as tunable Seebeck coefficients - which is achieved by modulating their electrical conductivity via simple redox reactions. Using these thermoelectric properties, all-organic flexible thermoelectric devices, such as temperature sensors, heat flux sensors, and thermoelectric generators, are being developed. In this article we discuss the combination of the two emerging fields: stretchable electronics and polymer thermoelectrics. The combination of elastic and thermoelectric properties seems to be unique for conducting polymers, and difficult to achieve with inorganic thermoelectric materials. We introduce the basic concepts, and state of the art knowledge, about the thermoelectric properties of conducting polymers, and illustrate the use of elastic thermoelectric conducting polymer aerogels that could be employed as temperature and pressure sensors in an electronic-skin.

  11. Polymer powders for selective laser sintering (SLS)

    Science.gov (United States)

    Schmid, Manfred; Amado, Antonio; Wegener, Konrad

    2015-05-01

    Selective Laser Sintering (SLS) is close to be accepted as a production technique (Additive Manufacturing). However, one problem limiting employment of SLS for additive manufacturing in a wide-ranging industrial scope is the narrow variety of applicable polymers. The commonly applied SLS powder to date is polyamide 12 (PA 12). PA 12 or ccompounds of PA 12 (dry blends) are approximately 90 % of complete industrial consumption. The remaining small quantity is distributed on polyamide 11 (PA11) and some other `exotic' polymers (TPU, PEBA, P(E)EK). Industry is awaiting commodity polymers like polypropylene (PP) or polyethylene (PE) crucial to open new market segments. But several approaches launching those polymers failed. But what are the reasons for the difficulties in developing new SLS powders? The contribution is to answer this and highlights the combination of intrinsic and extrinsic polymer properties necessary to generate a polymer powder promising for SLS application. Particle shape, powder distribution, thermal, rheological and optical requirements must be considered and only a particularly controlled property combination leads to successful SLS implementation. Thermal behavior, particle shape and -distribution is discussed in detail, although the other properties can't be disregarded for providing new commercially successful SLS powder finally.

  12. Nanocomposite polymer electrolyte for rechargeable magnesium batteries

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Yuyan; Rajput, Nav Nidhi; Hu, Jian Z.; Hu, Mary Y.; Liu, Tianbiao L.; Wei, Zhehao; Gu, Meng; Deng, Xuchu; Xu, Suochang; Han, Kee Sung; Wang, Jiulin; Nie, Zimin; Li, Guosheng; Zavadil, K.; Xiao, Jie; Wang, Chong M.; Henderson, Wesley A.; Zhang, Jiguang; Wang, Yong; Mueller, Karl T.; Persson, Kristin A.; Liu, Jun

    2014-12-28

    Nanocomposite polymer electrolytes present new opportunities for rechargeable magnesium batteries. However, few polymer electrolytes have demonstrated reversible Mg deposition/dissolution and those that have still contain volatile liquids such as tetrahydrofuran (THF). In this work, we report a nanocomposite polymer electrolyte based on poly(ethylene oxide) (PEO), Mg(BH4)2 and MgO nanoparticles for rechargeable Mg batteries. Cells with this electrolyte have a high coulombic efficiency of 98% for Mg plating/stripping and a high cycling stability. Through combined experiment-modeling investigations, a correlation between improved solvation of the salt and solvent chain length, chelation and oxygen denticity is established. Following the same trend, the nanocomposite polymer electrolyte is inferred to enhance the dissociation of the salt Mg(BH4)2 and thus improve the electrochemical performance. The insights and design metrics thus obtained may be used in nanocomposite electrolytes for other multivalent systems.

  13. High temperature performance of polymer composites

    CERN Document Server

    Keller, Thomas

    2014-01-01

    The authors explain the changes in the thermophysical and thermomechanical properties of polymer composites under elevated temperatures and fire conditions. Using microscale physical and chemical concepts they allow researchers to find reliable solutions to their engineering needs on the macroscale. In a unique combination of experimental results and quantitative models, a framework is developed to realistically predict the behavior of a variety of polymer composite materials over a wide range of thermal and mechanical loads. In addition, the authors treat extreme fire scenarios up to more than 1000°C for two hours, presenting heat-protection methods to improve the fire resistance of composite materials and full-scale structural members, and discuss their performance after fire exposure. Thanks to the microscopic approach, the developed models are valid for a variety of polymer composites and structural members, making this work applicable to a wide audience, including materials scientists, polymer chemist...

  14. Designed polymer-metal nanocomposites: On the use of colloidal polymer templates

    Energy Technology Data Exchange (ETDEWEB)

    Roth, Stephan V.; Buffet, Adeline; Couet, Sebastien; Gehrke, Rainer; Roehlsberger, Ralf; Rothkirch, Andre; Schlage, Kai [HASYLAB, DESY, Hamburg (Germany); Herzog, Gerd [HASYLAB, DESY, Hamburg (Germany); Inst. f. Exp. Phys., Univ. Hamburg (Germany); Wurth, Wilfried [Inst. f. Exp. Phys., Univ. Hamburg (Germany); Kaune, Gunar; Koerstgens, Volker; Meier, Robert; Metwalli, Ezzeldin; Mueller-Buschbaum, Peter [TU Muenchen, Physik-Department, Lehrstuhl E13, Garching (Germany)

    2009-07-01

    Polymer-metal nanocomposites are important materials for data storage, optical and electronic technologies. In combination with the wide variety of nanostructures offered by polymer materials in thin film technology, new routes for tailoring such nanocomposite devices are possible. Especially the use of colloidal nanoparticles is very attractive for magnetic data storage by ordering the colloidal nanoparticles. In our route to produce new colloidal polymer-metal nanocomposites, we combine the advantages of ordering colloidal thin films, polymer material characteristics and sputter deposition, leading to order on multiple length scales, from metal nanoparticle to large-scale domains. To understand the build-up of these multiple length scales, we use microbeam grazing incidence small angle x-ray scattering. We investigate IN-SITU the growth kinetics of magnetic and non-magnetic metals on colloidal polystyrene thin films as a function of the template treatment and present the resulting different growth regimes.

  15. Colloidal QDs-polymer nanocomposites

    Science.gov (United States)

    Gordillo, H.; Suárez, I.; Rodríguez-Cantó, P.; Abargues, R.; García-Calzada, R.; Chyrvony, V.; Albert, S.; Martínez-Pastor, J.

    2012-04-01

    Nanometer-size colloidal semiconductor nanocrystals, or Quantum Dots (NQD), are very prospective active centers because their light emission is highly efficient and temperature-independent. Nanocomposites based on the incorporation of QDs inside a polymer matrix are very promising materials for application in future photonic devices because they combine the properties of QDs with the technological feasibility of polymers. In the present work some basic applications of these new materials have been studied. Firstly, the fabrication of planar and linear waveguides based on the incorporation of CdS, CdSe and CdTe in PMMA and SU-8 are demonstrated. As a result, photoluminescence (PL) of the QDs are coupled to a waveguide mode, being it able to obtain multicolor waveguiding. Secondly, nanocomposite films have been evaluated as photon energy down-shifting converters to improve the efficiency of solar cells.

  16. Low bandgap semiconducting polymers for polymeric photovoltaics.

    Science.gov (United States)

    Liu, Chang; Wang, Kai; Gong, Xiong; Heeger, Alan J

    2016-08-22

    In order to develop high performance polymer solar cells (PSCs), full exploitation of the sun-irradiation from ultraviolet (UV) to near infrared (NIR) is one of the key factors to ensure high photocurrents and thus high efficiency. In this review, five of the effective design rules for approaching LBG semiconducting polymers with high molar absorptivity, suitable energy levels, high charge carrier mobility and high solubility in organic solvents are overviewed. These design stratagems include fused heterocycles for facilitating π-electron flowing along the polymer backbone, groups/atoms bridging adjacent rings for maintaining a high planarity, introduction of electron-withdrawing units for lowering the bandgap (Eg), donor-acceptor (D-A) copolymerization for narrowing Eg and 2-dimensional conjugation for broadened absorption and enhanced hole mobility. It has been demonstrated that LBG semiconducting polymers based on electron-donor units combined with strong electron-withdrawing units possess excellent electronic and optic properties, emerging as excellent candidates for efficient PSCs. While for ultrasensitive photodetectors (PDs), which have intensive applications in both scientific and industrial sectors, sensing from the UV to the NIR region is of critical importance. For polymer PDs, Eg as low as 0.8 eV has been obtained through a rational design stratagem, covering a broad wavelength range from the UV to the NIR region (1450 nm). However, the response time of the polymer PDs are severely limited by the hole mobility of LBG semiconducting polymers, which is significantly lower than those of the inorganic materials. Thus, further advancing the hole mobility of LBG semiconducting polymers is of equal importance as broadening the spectral response for approaching uncooled ultrasensitive broadband polymer PDs in the future study. PMID:26548402

  17. Low bandgap semiconducting polymers for polymeric photovoltaics.

    Science.gov (United States)

    Liu, Chang; Wang, Kai; Gong, Xiong; Heeger, Alan J

    2016-08-22

    In order to develop high performance polymer solar cells (PSCs), full exploitation of the sun-irradiation from ultraviolet (UV) to near infrared (NIR) is one of the key factors to ensure high photocurrents and thus high efficiency. In this review, five of the effective design rules for approaching LBG semiconducting polymers with high molar absorptivity, suitable energy levels, high charge carrier mobility and high solubility in organic solvents are overviewed. These design stratagems include fused heterocycles for facilitating π-electron flowing along the polymer backbone, groups/atoms bridging adjacent rings for maintaining a high planarity, introduction of electron-withdrawing units for lowering the bandgap (Eg), donor-acceptor (D-A) copolymerization for narrowing Eg and 2-dimensional conjugation for broadened absorption and enhanced hole mobility. It has been demonstrated that LBG semiconducting polymers based on electron-donor units combined with strong electron-withdrawing units possess excellent electronic and optic properties, emerging as excellent candidates for efficient PSCs. While for ultrasensitive photodetectors (PDs), which have intensive applications in both scientific and industrial sectors, sensing from the UV to the NIR region is of critical importance. For polymer PDs, Eg as low as 0.8 eV has been obtained through a rational design stratagem, covering a broad wavelength range from the UV to the NIR region (1450 nm). However, the response time of the polymer PDs are severely limited by the hole mobility of LBG semiconducting polymers, which is significantly lower than those of the inorganic materials. Thus, further advancing the hole mobility of LBG semiconducting polymers is of equal importance as broadening the spectral response for approaching uncooled ultrasensitive broadband polymer PDs in the future study.

  18. Suspensions of polymer-grafted nanoparticles with added polymers — Structure and effective pair-interactions

    OpenAIRE

    Chandran, Sivasurender; Saw, Shibu; Kandar, A. K.; Dasgupta, C; Sprung, M.; Basu, Jaydeep

    2015-01-01

    We present the results of combined experimental and theoretical (molecular dynamics simulations and integral equation theory) studies of the structure and effective interactions of suspensions of polymer grafted nanoparticles (PGNPs) in the presence of linear polymers. Due to the absence of systematic experimental and theoretical studies of PGNPs, it is widely believed that the structure and effective interactions in such binary mixtures would be very similar to those of an analogous soft col...

  19. Phase behaviour of rod-like colloid + flexible polymer mixtures

    NARCIS (Netherlands)

    Lekkerkerker, H.N.W.; Stroobants, A.

    1994-01-01

    The effect of non-adsorbing, flexible polymer on the isotropic-nematic transition in dispersions of rod-like colloids is investigated. A widening of the biphasic gap is observed, in combination with a marked polymer partitioning between the coexisting phases. Under certain conditions, areas of isotr

  20. Recent progress in polymer/layered double hydroxide nanocomposites

    Institute of Scientific and Technical Information of China (English)

    DING Peng; CHEN Wei; QU Baojun

    2006-01-01

    New developments in the studies of nanocomposites based on polymer matrixes and layered double hydroxides (LDHs)in recent years are reviewed combining our relative research work, among which the synthesis techniques, the physicochemical characterizations, and the improved material properties are especially discussed. The possible application of polymer/LDH nanocomposites is also proposed.

  1. Polymer dynamics from synthetic polymers to proteins

    Indian Academy of Sciences (India)

    D Richter; R Biehl; M Monkenbush; B Hoffmann; R Merkel

    2008-10-01

    Starting from the standard model of polymer motion - the Rouse model - we briefly present some key experimental results on the mesoscopic dynamics of polymer systems. We touch the role of topological confinement as expressed in the reptation model and discuss in some more detail processes limiting the confinement. In the second part we relate to some new developments concerning the measurement of large-scale internal dynamics of proteins by neutron spin echo.

  2. Hybrid polymer photonic crystal fiber with integrated chalcogenide glass nanofilms

    DEFF Research Database (Denmark)

    Markos, Christos; Kubat, Irnis; Bang, Ole

    2014-01-01

    The combination of chalcogenide glasses with polymer photonic crystal fibers (PCFs) is a difficult and challenging task due to their different thermo-mechanical material properties. Here we report the first experimental realization of a hybrid polymer-chalcogenide PCF with integrated As2S3 glass...... makes the polymer PCF nonlinear and provides a possibility to shift the transmission band edges as much as 17 nm by changing the intensity. The proposed fabrication technique constitutes a new highway towards all-fiber nonlinear tunable devices based on polymer PCFs, which at the moment is not possible...

  3. CO2 -Responsive polymers.

    Science.gov (United States)

    Lin, Shaojian; Theato, Patrick

    2013-07-25

    This Review focuses on the recent progress in the area of CO2 -responsive polymers and provides detailed descriptions of these existing examples. CO2 -responsive polymers can be categorized into three types based on their CO2 -responsive groups: amidine, amine, and carboxyl groups. Compared with traditional temperature, pH, or light stimuli-responsive polymers, CO2 -responsive polymers provide the advantage to use CO2 as a "green" trigger as well as to capture CO2 directly from air. In addition, the current challenges of CO2 -responsive polymers are discussed and the different solution methods are compared. Noteworthy, CO2 -responsive polymers are considered to have a prosperous future in various scientific areas.

  4. Polymer radiation chemistry

    International Nuclear Information System (INIS)

    This article reviews some of the work carried out in the Polymer and Radiation Group at the University of Queensland over the past ten years. The objective of the work has been to investigate the relationships between polymer structure and sensitivity towards high energy radiation, including 60Co gamma radiation, electron beams and UV radiation. A range of synthetic polymers containing carboxyl groups, acrylate groups, sulfone groups, amide linkages and aromatic residues have been investigated. (author). 18 refs, 2 figs, 4 tabs

  5. BSA Hybrid Synthesized Polymer

    Institute of Scientific and Technical Information of China (English)

    Zong Bin LIU; Xiao Pei DENG; Chang Sheng ZHAO

    2006-01-01

    Bovine serum albumin (BSA), a naturally occurring biopolymer, was regarded as a polymeric material to graft to an acrylic acid (AA)-N-vinyl pyrrolidone (NVP) copolymer to form a biomacromolecular hybrid polymer. The hybrid polymer can be blended with polyethersulfone (PES) to increase the hydrophilicity of the PES membrane, which suggested that the hybrid polymer might have a wide application in the modification of biomaterials.

  6. Multilayer polymer microspot targets

    International Nuclear Information System (INIS)

    Last year the authors reported on the development of a seeded microspot x-ray diagnostic target. This target consisted of a 300-μm-diam, 2-μm-thick disk of silicon or sulfur-seeded hydrocarbon polymer nested tightly in a hole in a 2-μm-thick film of pure hydrocarbon polymer. This year they extended our work on the microspot target, fully encapsulating the microspot in what they call the multilayer polymer microspot target

  7. Nanostructured polymers for photonics

    OpenAIRE

    Chantal Paquet; Eugenia Kumacheva

    2008-01-01

    We review recent progress in the development of polymer nanostructured materials with periodic structures and compositions having applications in photonics and optical data storage. This review provides a brief description of the microfabrication and self-assembly methods used for the production of polymer materials with periodic structures, and highlights the properties and applications of photonic materials derived from block copolymers, colloid crystals, and microfabricated polymers. We co...

  8. Thermally conductive polymers

    Science.gov (United States)

    Byrd, N. R.; Jenkins, R. K.; Lister, J. L. (Inventor)

    1971-01-01

    A thermally conductive polymer is provided having physical and chemical properties suited to use as a medium for potting electrical components. The polymer is prepared from hydroquinone, phenol, and formaldehyde, by conventional procedures employed for the preparation of phenol-formaldehyde resins. While the proportions of the monomers can be varied, a preferred polymer is formed from the monomers in a 1:1:2.4 molar or ratio of hydroquinone:phenol:formaldehyde.

  9. Antioxidant Stabilisation of Polymers

    Science.gov (United States)

    Shlyapnikov, Yurii A.

    1981-06-01

    Physicochemical aspects of the stabilisation of polymers are discussed. Attention is paid mainly to the aging and stabilisation of polymers under processing conditions. Topics considered are the kinetics and mechanism of the high-temperature oxidation of polymers, critical phenomena in the inhibited oxidation of polymers, the theory of synergism and antagonism among antioxidants, the reasons for differences in efficiency of antioxidants, and certain aspects of the relation between the efficiency of antioxidants and their molecular structure. A list of 132 references is included.

  10. Characterisation of polymers, 1

    CERN Document Server

    Crompton, Roy

    2008-01-01

    This essential guide to Polymer Characterisation is a complete compendium of methodologies that have evolved for the determination of the chemical composition of polymers. This 478-page book gives an up-to-date and thorough exposition of the state-of-the-art theories and availability of instrumentation needed to effect chemical and physical analysis of polymers. This is supported by approximately 1200 references. Volume 1 covers the methodology used for the determination of metals, non-metals and organic functional groups in polymers, and for the determination of the ratio in which different m

  11. Biopolymers Versus Synthetic Polymers

    Directory of Open Access Journals (Sweden)

    Florentina Adriana Cziple

    2008-10-01

    Full Text Available This paper present an overview of important synthetic and natural polymers with emphasis on polymer structure, the chemistry of polymer formation. an introduction to polymer characterization. The biodegradation process can take place aerobically and anaerobically with or without the presence of light. These factors allow for biodegradation even in landfill conditions which are normally inconducive to any degradation. The sheeting used to make these packages differs significantly from other “degradable plastics” in the market as it does not attempt to replace the current popular materials but instead enhances them by rendering them biodegradable.

  12. Nanostructured polymers for photonics

    Directory of Open Access Journals (Sweden)

    Chantal Paquet

    2008-04-01

    Full Text Available We review recent progress in the development of polymer nanostructured materials with periodic structures and compositions having applications in photonics and optical data storage. This review provides a brief description of the microfabrication and self-assembly methods used for the production of polymer materials with periodic structures, and highlights the properties and applications of photonic materials derived from block copolymers, colloid crystals, and microfabricated polymers. We conclude with a summary of current and future research efforts and opportunities in the development of polymer materials for photonic applications.

  13. Organic/Inorganic Hybrid Polymer/Clay Nanocomposites

    Science.gov (United States)

    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. Chemical virology: Packing polymers in protein cages

    Science.gov (United States)

    Cornelissen, Jeroen J. L. M.

    2012-10-01

    The combination of addressable synthetic macromolecules with proteins of precise structure and function often leads to materials with unique properties, as is now shown by the efficient multi-site initiation of polymer growth inside the cavity of a virus capsid.

  15. Protein-polymer nanoreactors for medical applications

    OpenAIRE

    Palivan, C. G.; Fischer-Onaca, O.; Delcea, M.; Itel, F.; Meier, W

    2012-01-01

    Major challenges that confront nanoscience in medicine today include the development of efficacious therapies with minimum side effects, diagnostic methods featuring significantly higher sensitivities and selectivities, and personalized diagnostics and therapeutics for theragnostic approaches. With these goals in mind, combining biological molecules and synthetic carriers/templates, such as polymer supramolecular assemblies, represents a very promising strategy. In this critical review, we pr...

  16. Polymers for Micropollutants Removal from Wastewater

    NARCIS (Netherlands)

    Mohd Amin, M.F.

    2015-01-01

    The presence of micropollutants, especially pharmaceuticals, in wastewater has become a significant concern to both the water treatment industry as well as consumers. A new method of treatment was developed to curb this problem. The use of polymers as flocculants and combining them with materials he

  17. Interpenetrating networks of two conducting polymers

    DEFF Research Database (Denmark)

    Winther-Jensen, Bjørn; West, Keld

    2005-01-01

    Interpenetrating networks (IPNs) of two conjugated polymers are prepared by a combination of a chemical oxidation step and a vapour phase polymerisation step on non-conducting surfaces. In this work ferric tosylate was used as the oxidant as it gives very smooth and homogeneous coatings...

  18. Triclosan antimicrobial polymers

    Science.gov (United States)

    Petersen, Richard C.

    2016-01-01

    Triclosan antimicrobial molecular fluctuating energies of nonbonding electron pairs for the oxygen atom by ether bond rotations are reviewed with conformational computational chemistry analyses. Subsequent understanding of triclosan alternating ether bond rotations is able to help explain several material properties in Polymer Science. Unique bond rotation entanglements between triclosan and the polymer chains increase both the mechanical properties of polymer toughness and strength that are enhanced even better through secondary bonding relationships. Further, polymer blend compatibilization is considered due to similar molecular relationships and polarities. With compatibilization of triclosan in polymers a more uniform stability for nonpolar triclosan in the polymer solid state is retained by the antimicrobial for extremely low release with minimum solubility into aqueous solution. As a result, triclosan is projected for long extended lifetimes as an antimicrobial polymer additive. Further, triclosan rapid alternating ether bond rotations disrupt secondary bonding between chain monomers in the resin state to reduce viscosity and enhance polymer blending. Thus, triclosan is considered for a polymer additive with multiple properties to be an antimicrobial with additional benefits as a nonpolar toughening agent and a hydrophobic wetting agent. The triclosan material relationships with alternating ether bond rotations are described through a complete different form of medium by comparisons with known antimicrobial properties that upset bacterial cell membranes through rapid fluctuating mechanomolecular energies. Also, triclosan bond entanglements with secondary bonding can produce structural defects in weak bacterial lipid membranes requiring pliability that can then interfere with cell division. Regarding applications with polymers, triclosan can be incorporated by mixing into a resin system before cure, melt mixed with thermoplastic polymers that set on cooling

  19. Oriented nanofibers embedded in a polymer matrix

    Science.gov (United States)

    Barrera, Enrique V. (Inventor); Rodriguez-Macias, Fernando J. (Inventor); Lozano, Karen (Inventor); Chibante, Luis Paulo Felipe (Inventor); Stewart, David Harris (Inventor)

    2011-01-01

    A method of forming a composite of embedded nanofibers in a polymer matrix is disclosed. The method includes incorporating nanofibers in a plastic matrix forming agglomerates, and uniformly distributing the nanofibers by exposing the agglomerates to hydrodynamic stresses. The hydrodynamic said stresses force the agglomerates to break apart. In combination or additionally elongational flow is used to achieve small diameters and alignment. A nanofiber reinforced polymer composite system is disclosed. The system includes a plurality of nanofibers that are embedded in polymer matrices in micron size fibers. A method for producing nanotube continuous fibers is disclosed. Nanofibers are fibrils with diameters of 100 nm, multiwall nanotubes, single wall nanotubes and their various functionalized and derivatized forms. The method includes mixing a nanofiber in a polymer; and inducing an orientation of the nanofibers that enables the nanofibers to be used to enhance mechanical, thermal and electrical properties. Orientation is induced by high shear mixing and elongational flow, singly or in combination. The polymer may be removed from said nanofibers, leaving micron size fibers of aligned nanofibers.

  20. Viscoelasticity and primitive path analysis of entangled polymer liquids: From f-actin to polyethylene

    OpenAIRE

    Uchida, Nariya; Grest, Gary S.; Everaers, Ralf

    2007-01-01

    We combine computer simulations and scaling arguments to develop a unified view of polymer entanglement based on the primitive path analysis (PPA) of the microscopic topological state. Our results agree with experimentally measured plateau moduli for three different polymer classes over a wide rangeof reduced polymer densities: (i) semi-dilute theta solutions of synthetic polymers, (ii) the corresponding dense melts above the glass transition or crystallization temperature, and (iii) solution...

  1. Luminescent composite polymer fibers: In situ synthesis of silver nanoclusters in electrospun polymer fibers and application

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Wenran, E-mail: gaoshang5566@126.com [State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, Jilin University, Changchun 130012 (China); Wang, Xumei, E-mail: wxmddp@163.com [Chinese National Petroleum Corporation Bohai Drilling Engineering Company Limited, Tianjin 300457 (China); Xu, Weiqing, E-mail: xuwq@jlu.edu.cn [State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, Jilin University, Changchun 130012 (China); Xu, Shuping, E-mail: xusp@jlu.edu.cn [State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, Jilin University, Changchun 130012 (China)

    2014-09-01

    The purpose of this study is to prepare multifunctional polymer fibers. We report a simple and controllable method for in situ synthesis of Ag nanoclusters (NCs) in electrospun polymer fibers via a photochemical reaction. The prepared composite polymer fibers emit pink luminescence and the luminescence property can be optimized by pH and Ag(I) precursor concentration. The as-prepared Ag NCs in electrospun polymer fibers were mainly Ag{sub 2–5} with a quantum yield of 6.81% and a lifetime of 2.29 ns. The in situ growth of Ag NCs avoids excessive surface modifications which may cause the aggregation of Ag NCs in many ex situ assembly methods. The combination of Ag NCs with polymer fibers greatly improves the stability of Ag NCs and broadens their applications. The storage of Ag NCs becomes facilitative due to the formation of bulky mat. Furthermore, these luminescence composite polymer fibers show strong antibacterial activity against Staphylococcus aureus (S. aureus). - Highlights: • Luminescent composite polymer nanofibers were fabricated. • Ag nanoclusters were in situ growth in the electrospun nanofiber membrane. • The prepared Ag nanoclusters have high chemical stability and antibacterial ability.

  2. Polymers in Waveguide Packaging

    Institute of Scientific and Technical Information of China (English)

    G; Z.; Xiao; C.; P.; Grover

    2003-01-01

    Polymers were successfully used in the packaging of waveguide-based photonic components in the area of fiber-to-waveguide coupling, waveguide die attachment, strain relief, and waveguide encapsulation. The application results of these polymers were described in this paper.

  3. Stiff Quantum Polymers

    OpenAIRE

    Kleinert, H

    2007-01-01

    At ultralow temperatures, polymers exhibit quantum behavior, which is calculated here for the second and fourth moments of the end-to-end distribution in the large-stiffness regime. The result should be measurable for polymers in wide optical traps.

  4. Melons are branched polymers

    CERN Document Server

    Gurau, Razvan

    2013-01-01

    Melonic graphs constitute the family of graphs arising at leading order in the 1/N expansion of tensor models. They were shown to lead to a continuum phase, reminiscent of branched polymers. We show here that they are in fact precisely branched polymers, that is, they possess Hausdorff dimension 2 and spectral dimension 4/3.

  5. Doped Chiral Polymer Metamaterials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Doped Chiral Polymer Metamaterials (DCPM) with tunable resonance frequencies have been developed by adding plasmonic inclusions into chiral polymers with variable...

  6. Selective micro metallization of polymers for biomedical and medical application

    DEFF Research Database (Denmark)

    Islam, Mohammad Aminul; Hansen, Hans Nørgaard; Tang, Peter Torben

    Integration of micro/nano metallic structures in polymer devices is a broad multi-disciplinary research field, consisting of various combinations of mechanical, chemical and physical fabrication methods. Some of these combinations have been known for years and other combinations or methods are very...

  7. Radiation-induced doping of conducting polymers

    International Nuclear Information System (INIS)

    Conducting polymers have the potential form many applications in electronics. The various patterns of doped regions of conducting polymers should be generated for the applications. Doping of conducting polymers is achieved by contact of the polymer with dopant or electrochemically. By these methods, doping occurs in the entire area exposed to the dopant. It is necessary to combine these doping techniques with lithography for achieving the patterned doping. Radiation-induced doping effects of conducting polymers have been reported. The doping is performed by irradiation of polymers in an atmosphere of gases, which do not react without irradiation, such as CH3Br, SF6, and N2O. If only the irradiated area was doped, patterned doping could be achieved without using lithography technique. We have elucidated the mechanism of the radiation-induced doping. The electrical conductivity was increased by irradiation the gas near the polymer film without irradiating the film itself. This result indicates that dopants were generated upon irradiation in the gas phase and the dopants react with the polymer. Hence, the pattern of doping is blurred by this method. We then developed another method of radiation-induced doping. Solid dopant precursor was coated on the polymer, and irradiation was performed. Figure 1 shows the results for poly(3-octylhitophene)(P3OT) by this method. A film of poly(3-octylthiophene) was prepared by spin coating from a solution of tetrahydrofuran on a quartz plate. The thickness of the film was approximately 100 nm. The polymer film was dried overnight at 80 degree C in a vacuum, and Au electrodes were evaporated on the films for electrical conductivity measurements. Saturated solution of 1,2,5,6,9,10-hexabromocyclododecane (HBCD) in 1-bromopropane was dropped on the film and dried at room temperature in a vacuum. The film was put in a vacuum chamber, which has a 0.2-mm-thick Be window. X rays entered through the Be window, and the films were irradiated

  8. Theory of polymer blends

    International Nuclear Information System (INIS)

    We have recently developed a new theoretical approach to the study of polymer liquids. The theory is based on the ''reference interaction site model'' (RISM theory) of Chandler and Andersen, which has been successful in describing the structure of small molecule liquids. We have recently extended our polymer RISM theory to the case of polymer blends. In the present investigation we have applied this theory to two special binary blends: (1) the athermal mixture where we isolate structural effects, and (2) the isotopic mixture in which structurally identical polymer chains interact with dissimilar attractive interactions. By studying these two special cases we are able to obtain insights into the molecular factors which control the miscibility in polymer mixtures. 18 refs., 2 figs

  9. Electroactive polymers for sensing.

    Science.gov (United States)

    Wang, Tiesheng; Farajollahi, Meisam; Choi, Yeon Sik; Lin, I-Ting; Marshall, Jean E; Thompson, Noel M; Kar-Narayan, Sohini; Madden, John D W; Smoukov, Stoyan K

    2016-08-01

    Electromechanical coupling in electroactive polymers (EAPs) has been widely applied for actuation and is also being increasingly investigated for sensing chemical and mechanical stimuli. EAPs are a unique class of materials, with low-moduli high-strain capabilities and the ability to conform to surfaces of different shapes. These features make them attractive for applications such as wearable sensors and interfacing with soft tissues. Here, we review the major types of EAPs and their sensing mechanisms. These are divided into two classes depending on the main type of charge carrier: ionic EAPs (such as conducting polymers and ionic polymer-metal composites) and electronic EAPs (such as dielectric elastomers, liquid-crystal polymers and piezoelectric polymers). This review is intended to serve as an introduction to the mechanisms of these materials and as a first step in material selection for both researchers and designers of flexible/bendable devices, biocompatible sensors or even robotic tactile sensing units. PMID:27499846

  10. Ion Implantation of Polymers

    DEFF Research Database (Denmark)

    Popok, Vladimir

    2012-01-01

    The current paper presents a state-of-the-art review in the field of ion implantation of polymers. Numerous published studies of polymers modified by ion beams are analysed. General aspects of ion stopping, latent track formation and changes of structure and composition of organic materials...... are discussed. Related to that, the effects of radiothermolysis, degassing and carbonisation are considered. Specificity of depth distributions of implanted into polymers impurities is analysed and the case of high-fluence implantation is emphasised. Within rather broad topic of ion bombardment, the focus...... is put on the low-energy implantation of metal ions causing the nucleation and growth of nanoparticles in the shallow polymer layers. Electrical, optical and magnetic properties of metal/polymer composites are under the discussion and the approaches towards practical applications are overviewed....

  11. Antiviral Polymer Therapeutics

    DEFF Research Database (Denmark)

    Smith, Anton Allen Abbotsford

    2014-01-01

    and the drug which increased the potency of the conjugates significantly. A different approach to drug delivery is that of surface mediated drug delivery. Hydrogels of poly(vinyl alcohol) has shown great promise in this regard. The chemical opportunities of this polymer are explored through the virtues...... of reversible-addition-fragmentation chain transfer polymerization, which not only controls the size of polymer, but also allows the introduction of a terminal amine on the polymer which can be used for further conjugation. This has allowed for not only fluorescent labeling of the polymer, but also protein......The field of drug delivery is in essence an exercise in engineered pharmacokinetics. Methods of doing so have been developed through the introduction of a vehicle carrying the drug, either by encapsulation or covalent attachment. The emergence of polymer therapeutics in anticancer therapy has...

  12. Polymer wear evaluation

    DEFF Research Database (Denmark)

    Lagerbon, Mikkel; Sivebæk, Ion Marius

    2012-01-01

    Polymer wear plays an increasing role in manufacturing of machine parts for e.g. medical devices. Some of these have an expected lifetime of five to eight years during which very little wear of the components is acceptable. Too much wear compromises the dosage accuracy of the device and thereby...... the safety of the patients. Prediction of the wear of polymers is complicated by the low thermal conductivity of this kind of material. It implies that any acceleration of testing conditions by increased contact pressure and/or sliding velocity will make the polymer fail due to exaggerated heat buildup....... This is not the kind of wear observed in medical devices. In the present work a method was developed capable of evaluating the wear progression in polymer-polymer contacts. The configuration of the setup is injection moulded specimens consisting of an upper part having a toroid shape and a lower flat part. The sliding...

  13. Study of Hydrophobic and Ionizable Hydrophilic Copolymers at Polymer/Solid and Polymer/Liquid Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Perahia, Dvora

    2011-11-01

    Joint experimental-computational efforts were set to characterize the interfacial effects on the structure and dynamics of polymers consisting of highly rigid hydrophilic-ionizable and hydrophobic sub-units within one polymeric chain casted into thin films of several molecular dimensions. Focusing on the ultra thin film region we separate out the interfacial effects from bulk characteristics. Specifically, the study sought to: identify the parameters that control the formation of a stable polymer-solid interface. The study consists of two components, experimental investigations and computational efforts. The experimental component was designed to derive empirical trends that can be used to correlate the set of coupled polymer molecular parameters with the interfacial characteristics of these polymers, and their response to presence of solvents. The computational study was designed to provide molecular insight into the ensemble averages provided by the experimental efforts on multiple length scales from molecular dimensions, to the nanometer lengths to a macroscopic understanding of solvent interactions with structured polymers. With the ultimate goal of correlating molecular parameters to structure, dynamics and properties of ionic polymers, the first stage of the research began with the study of two systems, one which allowed tailoring the flexibility of the backbone without the presence of ionic groups, but with a potential to sulfonate groups at a later stage, and a polymer whose backbone is rigid and the density of the ionic group can be varied. The combined experimental and computational studies significantly extended the understanding of polymers at interfaces from model systems to polydispersed copolymers with blocks of varying nature and complexity. This new insight directly affects the design of polymers for sustainable energy applications from batteries and fuel cells to solar energy.

  14. Polymer-Polymer Miscibility and Enthalpy Relaxations

    NARCIS (Netherlands)

    Bosma, Martin; Brinke, Gerrit ten; Ellis, Thomas S.

    1988-01-01

    Annealing of polymers below the glass transition temperature results in a decrease in enthalpy that is recovered during heating. The enthalpy recovery is visible as an endothermic peak in a differential scanning calorimetry (DSC) scan. The position of this peak depends on the thermal treatment given

  15. Neutron studies of polymers

    International Nuclear Information System (INIS)

    The possibility to contrast given fractions of a polymer system at a cost of a low enthalpy difference is responsible for the success of the neutron method. This approach is especially useful for polymers as compared to colloids or simple liquids, because of the significative intra- and inter-molecular correlations. In this respect, the pseudo diblock copolymer constitutes one of the best test molecule of homogeneous polymer system. A review is given of main results: polymer size in melts, true backbone conformation and universal constants related to polymer structures. Effects of mechanical stress, of mesogenic order have been revealed. Neutron spin-echo experiments have given characteristic dispersion relations of intra- and inter-polymer diffusive motions. The labelling method is however more powerful than first realized. The amplitude associated with a polymer structure at an interface has been obtained directly (as in ellipsometry) with the use of contrast variation. Such structures are currently investigated by neutron reflectivity. Latest developments are found in the use of spin polarized targets, from which important cross correlations are derived

  16. Polymer Science Pilot Program

    Science.gov (United States)

    Maier, Mary L.

    1996-07-01

    Natural polymers such as cellulose, proteins, and DNA have been part of earth's store of chemicals long before chemists existed. However, polymers synthesized by chemists first appeared on this planet only sixty years ago. A veritable explosion of materials first known as plastics, later polymers, followed. Today polymers, natural and synthetic, are everywhere, and it is appropriate to include an introduction to polymers in the education of future scientists. The Polymer Science Pilot Program consists of a sequence of experiences with polymers, designed to focus upon the ways in which these materials resemble and/or compare with nonpolymers in physical properties, versatility, and function. The modular format makes it possible for educators to select specific sections of the program for integration into other college chemistry courses. The team learning aspect of he program can also be recommended to educators who select a specific module. When this program was presented at a Middle Atlantic Regional Meeting of the American Chemical Society, some attendees were concerned about the limited number of participants as compared with the seemingly large number of college instructors. It was explained that the concentrated format of the four day program necessitates this instructor-to-student ratio; one class consisting of eighteen participants was tried and it was found that some aspects of the program, especially the research paper preparation, were not as thoroughly moderated.

  17. Ion implantation in polymers

    Science.gov (United States)

    Wintersgill, M. C.

    1984-02-01

    An introductory overview will be given of the effects of ion implantation on polymers, and certain areas will be examined in more detail. Radiation effects in general and ion implantation in particular, in the field of polymers, present a number of contrasts with those in ionic crystals, the most obvious difference being that the chemical effects of both the implanted species and the energy transfer to the host may profoundly change the nature of the target material. Common effects include crosslinking and scission of polymer chains, gas evolution, double bond formation and the formation of additional free radicals. Research has spanned the chemical processes involved, including polymerization reactions achievable only with the use of radiation, to applied research dealing both with the effects of radiation on polymers already in commercial use and the tailoring of new materials to specific applications. Polymers are commonly divided into two groups, in describing their behavior under irradiation. Group I includes materials which form crosslinks between molecules, whereas Group II materials tend to degrade. In basic research, interest has centered on Group I materials and of these polyethylene has been studied most intensively. Applied materials research has investigated a variety of polymers, particularly those used in cable insulation, and those utilized in ion beam lithography of etch masks. Currently there is also great interest in enhancing the conducting properties of polymers, and these uses would tend to involve the doping capabilities of ion implantation, rather than the energy deposition.

  18. A numerical model to simulate foams during devolatilization of polymers

    Science.gov (United States)

    Khan, Irfan; Dixit, Ravindra

    2014-11-01

    Customers often demand that the polymers sold in the market have low levels of volatile organic compounds (VOC). Some of the processes for making polymers involve the removal of volatiles to the levels of parts per million (devolatilization). During this step the volatiles are phase separated out of the polymer through a combination of heating and applying lower pressure, creating foam with the pure polymer in liquid phase and the volatiles in the gas phase. The efficiency of the devolatilization process depends on predicting the onset of solvent phase change in the polymer and volatiles mixture accurately based on the processing conditions. However due to the complex relationship between the polymer properties and the processing conditions this is not trivial. In this work, a bubble scale model is coupled with a bulk scale transport model to simulate the processing conditions of polymer devolatilization. The bubble scale model simulates the nucleation and bubble growth based on the classical nucleation theory and the popular ``influence volume approach.'' As such it provides the information of bubble size distribution and number density inside the polymer at any given time and position. This information is used to predict the bulk properties of the polymer and its behavior under the applied processing conditions. Initial results of this modeling approach will be presented.

  19. Influence of Polymer Molecular Weight on Drug-Polymer Solubility

    DEFF Research Database (Denmark)

    Knopp, Matthias Manne; Olesen, Niels Erik; Holm, Per;

    2015-01-01

    In this study, the influence of polymer molecular weight on drug-polymer solubility was investigated using binary systems containing indomethacin (IMC) and polyvinylpyrrolidone (PVP) of different molecular weights. The experimental solubility in PVP, measured using a differential scanning...... the solubility in the polymer. Hence, if a drug is soluble in an analogue of the polymer, it is most likely also soluble in the polymer. In conclusion, the solubility of a given drug-polymer system is determined by the strength of the drug-polymer interactions rather than the molecular weight of the...... polymer. Therefore, during the first screenings for drug solubility in polymers, only one representative molecular weight per polymer is needed....

  20. Conducting polymers: Synthesis and industrial applications

    Energy Technology Data Exchange (ETDEWEB)

    Gottesfeld, S. [Los Alamos National Laboratory, NM (United States)

    1995-05-01

    The Conducting Polymer project funded by the AIM Materials Program is developing new methods for the synthesis of electronically conducting polymers and is evaluating new industrial applications for these materials which will result in significant reductions in energy usage or industrial waste. The applications specifically addressed during FY 1994 are electrochemical capacitors and membranes for gas separation. As an active material in electrochemical capacitors, conducting polymers have the potential of storing large amounts of electrical energy in low cost materials. Such devices are needed in electronics for power failure back-up and peak power, in power supplies for filtering, and in electric vehicles for peak power and load leveling. As a gas electrically adapt the membrane for specific gas combinations. Potential energy savings in the US. for this application are estimated at 1 to 3 quads/yr.

  1. Soluble porphyrin polymers

    Science.gov (United States)

    Gust, Jr., John Devens; Liddell, Paul Anthony

    2015-07-07

    Porphyrin polymers of Structure 1, where n is an integer (e.g., 1, 2, 3, 4, 5, or greater) ##STR00001## are synthesized by the method shown in FIGS. 2A and 2B. The porphyrin polymers of Structure 1 are soluble in organic solvents such as 2-MeTHF and the like, and can be synthesized in bulk (i.e., in processes other than electropolymerization). These porphyrin polymers have long excited state lifetimes, making the material suitable as an organic semiconductor for organic electronic devices including transistors and memories, as well as solar cells, sensors, light-emitting devices, and other opto-electronic devices.

  2. Polymer artificial muscles

    Directory of Open Access Journals (Sweden)

    Tissaphern Mirfakhrai

    2007-04-01

    Full Text Available The various types of natural muscle are incredible material systems that enable the production of large deformations by repetitive molecular motions. Polymer artificial muscle technologies are being developed that produce similar strains and higher stresses using electrostatic forces, electrostriction, ion insertion, and molecular conformational changes. Materials used include elastomers, conducting polymers, ionically conducting polymers, and carbon nanotubes. The mechanisms, performance, and remaining challenges associated with these technologies are described. Initial applications are being developed, but further work by the materials community should help make these technologies applicable in a wide range of devices where muscle-like motion is desirable.

  3. Development of Silicate Polymers

    DEFF Research Database (Denmark)

    Søgaard, Erik Gydesen; Simonsen, Morten Enggrob

      The development of inorganic polymers is a new promising technology that may be used in many applications. The syntheses of inorganic polymers are normally carried out either by mixing an amorphous material for example silicium dioxide with a mineral base or dissolving metal oxids or metal...... hydroxide in acid and increase pH to saturation of the metal hydroxide. It is assumed that the syntheses of the inorganic polymer are carried out through polymerisation of oligomers (dimer, trimer) which provide the actual unit structures of the three dimensional macromolecular structure. In this work...

  4. Lectures on random polymers

    CERN Document Server

    Caravenna, Francesco; Pétrélis, Nicolas

    2011-01-01

    These lecture notes are a guided tour through the fascinating world of polymer chains interacting with themselves and/or with their environment. The focus is on the mathematical description of a number of physical and chemical phenomena, with particular emphasis on phase transitions and space-time scaling. The topics covered, though only a selection, are typical for the area. Sections 1-3 describe models of polymers without disorder, Sections 4-6 models of polymers with disorder. Appendices A-E contain tutorials in which a number of key techniques are explained in more detail.

  5. Biomedical applications of polymers

    CERN Document Server

    Gebelein, C G

    1991-01-01

    The biomedical applications of polymers span an extremely wide spectrum of uses, including artificial organs, skin and soft tissue replacements, orthopaedic applications, dental applications, and controlled release of medications. No single, short review can possibly cover all these items in detail, and dozens of books andhundreds of reviews exist on biomedical polymers. Only a few relatively recent examples will be cited here;additional reviews are listed under most of the major topics in this book. We will consider each of the majorclassifications of biomedical polymers to some extent, inclu

  6. The interplay of nanostructure and efficiency of polymer solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Yin Chunhong

    2008-12-04

    The aim of this thesis is to achieve a deep understanding of the working mechanism of polymer based solar cells and to improve the device performance. Two types of the polymer based solar cells are studied here: the polymer-polymer solar cells, and the polymer-small molecule solar cell which has polymer as electron donor incorporating with organic small molecule as electron acceptor. For the polymer-polymer devices, I compared the photocurrent characteristics of bilayer and blend devices as well as the blend devices with different nano-morphology, which is fine tuned by applying solvents with different boiling points. The main conclusion based on the complementary measurements is that the performance-limiting step is the field-dependent generation of free charge carriers, while bimolecular recombination and charge extraction do not compromise device performance. Regarding polymer-small molecular hybrid solar cells I combined the hole-transporting polymer M3EH-PPV with a novel small molecule electron acceptor vinazene. This molecule can be either deposited from solution or by thermal evaporation, allowing for a large variety of layer architectures to be realized. I then demonstrated that the layer architecture has a large influence on the photovoltaic properties. Solar cells with very high fill factors of up to 57 % and an open circuit voltage of 1V without thermal treatment of the devices were achieved. In the past, fill factors of solar cells exceeding 50 % have only been observed when using fullerene-derivatives as the electron-acceptor. The finding that proper processing of polymer-vinazene devices leads to similar high values is a major step towards the design of efficient polymer-based solar cells. (orig.)

  7. Precursor polymer approach towards functional conjugated polymer networks and ultrathin film electro-optical applications

    Science.gov (United States)

    Taranekar, Prasad

    Conjugated polymers are organic semiconductors which are of interest to a wide variety of optical, electronic, opto-electronic, and sensory applications; including light emitting diodes, thin film transistors, photovoltaic cells, and chemical sensors. While conducting polymers have some similarities to conventional polymeric materials, it is clearly the extensive main chain pi-conjugated structure and its implicit electro-optical properties that make it distinct. The same structure, however, gives it "chain stiffness" that affects its physical behavior. As a direct consequence of this, virtually all unsubstituted conducting polymers are found to be intractable and insoluble. This dissertation details the issue of tailoring the electro-optical properties and processability of conjugated polymers via a novel "precursor polymer approach". In this approach, electroactive side group units of either similar or different kind are tethered to a polymeric backbone. This combination determines the eventual electro-optical and electrochemical properties of these polymers including their ability to form ultrathin films. Thus, the desired macroscopic property is transformed by designing new precursor polymer structures, manipulating polymer-based compositions and blends, and the exploration and exploitation of their electrochemical processing conditions. In Chapters 2, 3, and 4, we have used single or binary electroactive compositions of species such as pyrrole, thiophene, carbazole and terthiophene are tethered to a linear polymeric backbone. Besides, the linear approach, in Chapters 5 and 6, we have also explored the use of generational dendrimers as backbone with carbazole units attached as peripheral electroactive groups. These precursor polymers were then subjected to electrochemical cross-linking to generate high optical quality ultrathin films on a conducting substrate such as indium tin oxide (ITO) or Au surfaces. The reaction of such electroactive species inimically

  8. Conducting polymers: Synthesis and industrial applications

    Energy Technology Data Exchange (ETDEWEB)

    Gottesfeld, S. [Los Alamos National Lab., NM (United States)

    1997-04-01

    The Conducting Polymer project funded by the AIM Program has developed new methods for the synthesis of conducting polymers and evaluated new industrial applications for these materials which will result in significant reductions in energy usage or industrial waste. The applications specifically addressed during FY 1996 included two ongoing efforts on membranes for gas separation and on electrochemical capacitors and a third new application: electrochemical reactors (ECRs) based on polymeric electrolytes. As a gas separation membrane, conducting polymers offer high selectivity and the potential to chemically or electrically adapt the membrane for specific gas combinations. Potential energy savings in the US for this application are estimated at 1 to 3 quads/yr. As an active material in electrochemical capacitors, electronically conducting polymers have the potential of storing large amounts of electric energy in low cost materials. Potential energy savings estimated at 1 quad/yr would result from introduction of electrochemical capacitors as energy storage devices in power trains of electric and hybrid vehicles, once such vehicles reach 20% of the total transportation market in the US. In the chlor-alkali industry, electrochemical reactors based on polymer electrolyte membranes consume around 1 % of the total electric power in the US. A new activity, started in FY 1996, is devoted to energy efficient ECRs. In the case of the chlor-alkali industry, energy savings as high as 50% seem possible with the novel ECR technology demonstrated by the author in 1996.

  9. Polymers for Protein Conjugation

    Directory of Open Access Journals (Sweden)

    Gianfranco Pasut

    2014-01-01

    Full Text Available Polyethylene glycol (PEG at the moment is considered the leading polymer for protein conjugation in view of its unique properties, as well as to its low toxicity in humans, qualities which have been confirmed by its extensive use in clinical practice. Other polymers that are safe, biodegradable and custom-designed have, nevertheless, also been investigated as potential candidates for protein conjugation. This review will focus on natural polymers and synthetic linear polymers that have been used for protein delivery and the results associated with their use. Genetic fusion approaches for the preparation of protein-polypeptide conjugates will be also reviewed and compared with the best known chemical conjugation ones.

  10. Electroactive polymers for sensing

    Science.gov (United States)

    2016-01-01

    Electromechanical coupling in electroactive polymers (EAPs) has been widely applied for actuation and is also being increasingly investigated for sensing chemical and mechanical stimuli. EAPs are a unique class of materials, with low-moduli high-strain capabilities and the ability to conform to surfaces of different shapes. These features make them attractive for applications such as wearable sensors and interfacing with soft tissues. Here, we review the major types of EAPs and their sensing mechanisms. These are divided into two classes depending on the main type of charge carrier: ionic EAPs (such as conducting polymers and ionic polymer–metal composites) and electronic EAPs (such as dielectric elastomers, liquid-crystal polymers and piezoelectric polymers). This review is intended to serve as an introduction to the mechanisms of these materials and as a first step in material selection for both researchers and designers of flexible/bendable devices, biocompatible sensors or even robotic tactile sensing units. PMID:27499846

  11. Shape-memory polymers

    Directory of Open Access Journals (Sweden)

    Marc Behl

    2007-04-01

    Full Text Available Shape-memory polymers are an emerging class of active polymers that have dual-shape capability. They can change their shape in a predefined way from shape A to shape B when exposed to an appropriate stimulus. While shape B is given by the initial processing step, shape A is determined by applying a process called programming. We review fundamental aspects of the molecular design of suitable polymer architectures, tailored programming and recovery processes, and the quantification of the shape-memory effect. Shape-memory research was initially founded on the thermally induced dual-shape effect. This concept has been extended to other stimuli by either indirect thermal actuation or direct actuation by addressing stimuli-sensitive groups on the molecular level. Finally, polymers are introduced that can be multifunctional. Besides their dual-shape capability, these active materials are biofunctional or biodegradable. Potential applications for such materials as active medical devices are highlighted.

  12. THERMOCHROMIC POLYMER MATERIALS

    Institute of Scientific and Technical Information of China (English)

    A.Seeboth; A.Klukowska; R.Ruhmann; D.L(o)tzsch

    2007-01-01

    Thermochromic polymers will play an extremely important role in the next future.The physical background of thermochromism and the state of development of thermochromic polymers based on light absorption effects are reported.In detail.the interactions between the polymer matrix and the thermochromic composite-composed of leuco or indicator dyes-are discussed on a molecular level.Thermochromic hydrogels with extremely high transparency,an outstanding switching behavior from colorless to colored or between different colors is presented.Preparation of thermosetting and thermoplastic polymers,including the resulting optical,and,for the first time,the mechanical properties are discussed in relation to matrix tuned high-resistant microcapsules.

  13. Polymers Best Paper Award 2015

    Directory of Open Access Journals (Sweden)

    Alexander Böker

    2015-01-01

    Full Text Available Polymers is instituting an annual award to recognize the outstanding papers in the area of polymer science published in Polymers. We are pleased to announce the second “Polymers Best Paper Award” for 2015 [1]. Nominations were selected by the Editor-in-Chief and Editorial Board members of Polymers from all papers published in 2011. The awards are issued to reviews and articles respectively. We are pleased to announce that the following five papers were chosen:[...

  14. Polymers Best Paper Award 2014

    Directory of Open Access Journals (Sweden)

    Alexander Böker

    2014-01-01

    Full Text Available Polymers is instituting an annual award to recognize outstanding papers in the area of polymer science published in Polymers. We are pleased to announce the first “Polymers Best Paper Award” for 2014. Nominations were selected by the Editor-in-Chief and Editorial Board members of Polymers from all papers published in 2010. The awards are issued to reviews and articles respectively.

  15. Supramolecular polymers in inhomogeneous systems

    OpenAIRE

    Zweistra, H.J.A.

    2007-01-01

    This thesis describes theoretical results of supramolecular polymers in inhomogeneous systems. Supramolecular polymers are linear assemblies of which the monomers are joined by reversible bonds. Many types of supramolecular polymers have been synthesized in recent years. Moreover, there are numerous compounds in nature which exhibit similar behavior. Simulations of coarse-grained models of supramolecular polymers yielded new insights into the properties of supramolecular polymers in inhomogen...

  16. Edible Polymers: Challenges and Opportunities

    OpenAIRE

    Subhas C. Shit; Shah, Pathik M.

    2014-01-01

    Edible polymers have established substantial deliberation in modern eons because of their benefits comprising use as edible materials over synthetic polymers. This could contribute to the reduction of environmental contamination. Edible polymers can practically diminish the complexity and thus improve the recyclability of materials, compared to the more traditional non-environmentally friendly materials and may be able to substitute such synthetic polymers. A synthetic hydrogel polymer unlock...

  17. Polymer optical motherboard technology

    Science.gov (United States)

    Keil, N.; Yao, H.; Zawadzki, C.; Grote, N.; Schell, M.

    2008-02-01

    In this paper, different hybridly integrated optical devices including optical multiplexer/ demultiplexer and optical transceivers are described. The devices were made using polymer planar light wave circuit (P2LC) technology. Laser diodes, photodiodes, and thin-film filters have been integrated. Key issues involved in this technology, in particular the coupling between laser diodes and polymer waveguides, and between waveguides and photodiodes and also fibers are discussed.

  18. Active Polymer Gel Actuators

    OpenAIRE

    Shuji Hashimoto; Ryo Yoshida; Yusuke Hara; Shingo Maeda

    2010-01-01

    Many kinds of stimuli-responsive polymer and gels have been developed and applied to biomimetic actuators or artificial muscles. Electroactive polymers that change shape when stimulated electrically seem to be particularly promising. In all cases, however, the mechanical motion is driven by external stimuli, for example, reversing the direction of electric field. On the other hand, many living organisms can generate an autonomous motion without external driving stimuli like self-beating of he...

  19. Polymer Protected Gold Nanoparticles

    OpenAIRE

    Shan, Jun

    2006-01-01

    Polymer protected gold nanoparticles have successfully been synthesized by both "grafting-from" and "grafting-to" techniques. The synthesis methods of the gold particles were systematically studied. Two chemically different homopolymers were used to protect gold particles: thermo-responsive poly(N-isopropylacrylamide), PNIPAM, and polystyrene, PS. Both polymers were synthesized by using a controlled/living radical polymerization process, reversible addition-fragmentation chain transfer (RAFT)...

  20. Dielectric Actuation of Polymers

    OpenAIRE

    Niu, Xiaofan

    2013-01-01

    Dielectric polymers are widely used in a plurality of applications, such as electrical insulation, dielectric capacitors, and electromechanical actuators. Dielectric polymers with large strain deformations under an electric field are named dielectric elastomers (DE), because of their relative low modulus, high elongation at break, and outstanding resilience. Dielectric elastomer actuators (DEA) are superior to traditional transducers as a muscle-like technology: large strains, high energy den...

  1. Toxicology of Biomedical Polymers

    OpenAIRE

    P. V. Vedanarayanan; A. C. Fernandez

    1987-01-01

    This paper deals with the various types of polymers, used in the fabrication of medical devices, their diversity of applications and toxic hazards which may arise out of their application. The potential toxicity of monomers and the various additives used in the manufacture of biomedical polymers have been discussed along with hazards which may arise out of processing of devices such as sterilization. The importance of quality control and stringent toxicity evaluation methods have been emphasi...

  2. Thermal conductivity and multiferroics of electroactive polymers and polymer composites

    Science.gov (United States)

    Jin, Jiezhu

    Electronically conducting polymers and electromechanical polymers are the two important branches of the cutting-edge electroactive polymers. They have shown significant impact on many modern technologies such as flat panel display, energy transport, energy conversion, sensors and actuators. To utilize conducting polymers in microelectronics, optoelectronics and thermoelectrics, it is necessary to have a comprehensive study of their thermal conductivity since thermal conductivity is a fundamental materials property that is particularly important and sometimes a determining factor of the device performance. For electromechanical polymers, larger piezoelectric effect will contribute to the improvement of magnetoelectric (ME) coupling efficiency in their multiferroic composites. This dissertation is devoted to characterizing electronically conducting polymers for their electrical and thermal conductivity, and developing new classes of electromechanical polymers and strain-mediated electromechanical polymer-based multiferroic ME composites. Conducting polymers opened up new possibilities for devices combining novel electrical and thermal properties, but there has been limited understanding of the length-scale effect of the electrical and thermal conductivity, and the mechanism underlying the electricity and heat transport behavior. In this dissertation, the analytical model and experimental technique are presented to measure the in-plane thermal conductivity of polyaniline thin films. For camphorsulfonic acid doped polyaniline patterned on silicon oxide/silicon substrate using photolithography and reactive ion etching, the thermal conductivity of the film with thickness of 20 nm is measured to be 0.0406 W/m˙K, which significantly deviates from their bulk (> 0.26 W/m˙K). The size effect on thermal conductivity at this scale is attributed to the significant phonon boundary scattering. When the film goes up to 130 nm thick, the thermal conductivity increases to 0.166 W

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

    Science.gov (United States)

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

    2015-01-01

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

  4. Reticulated Nanoporous Polymers by Controlled Polymerization-Induced Microphase Separation

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Myungeun; Hillmyer, Marc A. (UMM)

    2013-04-08

    Materials with percolating mesopores are attractive for applications such as catalysis, nanotemplating, and separations. Polymeric frameworks are particularly appealing because the chemical composition and the surface chemistry are readily tunable. We report on the preparation of robust nanoporous polymers with percolating pores in the 4- to 8-nanometer range from a microphase-separated bicontinuous precursor. We combined polymerization-induced phase separation with in situ block polymer formation from a mixture of multifunctional monomers and a chemically etchable polymer containing a terminal chain transfer agent. This marriage results in microphase separation of the mixture into continuous domains of the etchable polymer and the emergent cross-linked polymer. Precise control over pore size distribution and mechanical integrity renders these materials particularly suited for various advanced applications.

  5. Self-Sensing Ionic Polymer Actuators: A Review

    Directory of Open Access Journals (Sweden)

    Karl Kruusamäe

    2015-03-01

    Full Text Available Ionic electromechanically active polymers (IEAP are laminar composites that can be considered attractive candidates for soft actuators. Their outstanding properties such as low operating voltage, easy miniaturization, and noiseless operation are, however, marred by issues related to the repeatability in the production and operation of these materials. Implementing closed-loop control for IEAP actuators is a viable option for overcoming these issues. Since IEAP laminates also behave as mechanoelectrical sensors, it is advantageous to combine the actuating and sensing functionalities of a single device to create a so-called self-sensing actuator. This review article systematizes the state of the art in producing self-sensing ionic polymer actuators. The IEAPs discussed in this paper are conducting (or conjugated polymers actuators (CPA, ionic polymer-metal composite (IPMC, and carbonaceous polymer laminates.

  6. Rapid Polymer Sequencer

    Science.gov (United States)

    Stolc, Viktor (Inventor); Brock, Matthew W (Inventor)

    2013-01-01

    Method and system for rapid and accurate determination of each of a sequence of unknown polymer components, such as nucleic acid components. A self-assembling monolayer of a selected substance is optionally provided on an interior surface of a pipette tip, and the interior surface is immersed in a selected liquid. A selected electrical field is impressed in a longitudinal direction, or in a transverse direction, in the tip region, a polymer sequence is passed through the tip region, and a change in an electrical current signal is measured as each polymer component passes through the tip region. Each of the measured changes in electrical current signals is compared with a database of reference electrical change signals, with each reference signal corresponding to an identified polymer component, to identify the unknown polymer component with a reference polymer component. The nanopore preferably has a pore inner diameter of no more than about 40 nm and is prepared by heating and pulling a very small section of a glass tubing.

  7. Conductivity behaviour of polymer gel electrolytes: Role of polymer

    Indian Academy of Sciences (India)

    S S Sekhon

    2003-04-01

    Polymer is an important constituent of polymer gel electrolytes along with salt and solvent. The salt provides ions for conduction and the solvent helps in the dissolution of the salt and also provides the medium for ion conduction. Although the polymer added provides mechanical stability to the electrolytes yet its effect on the conductivity behaviour of gel electrolytes as well as the interaction of polymer with salt and solvent has not been conclusively established. The conductivity of lithium ion conducting polymer gel electrolytes decreases with the addition of polymer whereas in the case of proton conducting polymer gel electrolytes an increase in conductivity has been observed with polymer addition. This has been explained to be due to the role of polymer in increasing viscosity and carrier concentration in these gel electrolytes.

  8. East Coalinga polymer project: polymer comparisons. [California

    Energy Technology Data Exchange (ETDEWEB)

    Snell, G.

    1976-01-01

    Shell Oil Co. conducted a series of injection and filtration tests in the E. Colainga field, California, to determine the injection characteristics of biopolymer and polyacrylamides. The choice of Xanflood biopolymer was made in order to evaluate the relative merits of polymer flooding and waterflooding in the Temblor Zone II reservoir. Conclusions to the field injection tests were (1) Xanflood biopolymers maintain their mobility properties during these tests; (2) it is possible to remove unhydrated Xanflood biopolymer or unhydrated biopolymer and bacterial debris with DE Filtration without significant loss in biopolymer viscosity; (3) the introduction of an optimum level of shear in the biopolymer mixing process increases the mobility control available for a given concentration of polymer; (4) currently available commercial biopolymers cause well-bore impairment so that effective filtration of the polymer solution is required to maintain injectivity; (5) at test injection rates (33 bpd/ft), polyacrylamide loses most of its mobility control by shear degradation at the injection well perforations; (6) polyacrylamide can be delivered to the sand face without severe loss of viscosity; and (7) polyacrylamide will not impair the formation. (12 refs.)

  9. Electrically contractile polymers augment right ventricular output in the heart.

    Science.gov (United States)

    Ruhparwar, Arjang; Piontek, Patricia; Ungerer, Matthias; Ghodsizad, Ali; Partovi, Sasan; Foroughi, Javad; Szabo, Gabor; Farag, Mina; Karck, Matthias; Spinks, Geoffrey M; Kim, Seon Jeong

    2014-12-01

    Research into the development of artificial heart muscle has been limited to assembly of stem cell-derived cardiomyocytes seeded around a matrix, while nonbiological approaches to tissue engineering have rarely been explored. The aim of the study was to apply electrically contractile polymer-based actuators as cardiomyoplasty for positive inotropic support of the right ventricle. Complex trilayer polypyrrole (PPy) bending polymers for high-speed applications were generated. Bending motion occurred directly as a result of electrochemically driven charging and discharging of the PPy layers. In a rat model (n = 5), strips of polymers (3 × 20 mm) were attached and wrapped around the right ventricle (RV). RV pressure was continuously monitored invasively by direct RV cannulation. Electrical activation occurred simultaneously with either diastole (in order to evaluate the polymer's stand-alone contraction capacity; group 1) or systole (group 2). In group 1, the pressure generation capacity of the polymers was measured by determining the area under the pressure curve (area under curve, AUC). In group 2, the RV pressure AUC was measured in complexes directly preceding those with polymer contraction and compared to RV pressure complexes with simultaneous polymer contraction. In group 1, the AUC generated by polymer contraction was 2768 ± 875 U. In group 2, concomitant polymer contraction significantly increased AUC compared with complexes without polymer support (5987 ± 1334 U vs. 4318 ± 691 U, P ≤ 0.01). Electrically contractile polymers are able to significantly augment right ventricular contraction. This approach may open new perspectives for myocardial tissue engineering, possibly in combination with fetal or embryonic stem cell-derived cardiomyocytes.

  10. Plasmonic polymers unraveled through single particle spectroscopy

    Science.gov (United States)

    Slaughter, Liane S.; Wang, Lin-Yung; Willingham, Britain A.; Olson, Jana M.; Swanglap, Pattanawit; Dominguez-Medina, Sergio; Link, Stephan

    2014-09-01

    Plasmonic polymers are quasi one-dimensional assemblies of nanoparticles whose optical responses are governed by near-field coupling of localized surface plasmons. Through single particle extinction spectroscopy correlated with electron microscopy, we reveal the effect of the composition of the repeat unit, the chain length, and extent of disorder on the energies, intensities, and line shapes of the collective resonances of individual plasmonic polymers constructed from three different sizes of gold nanoparticles. Our combined experimental and theoretical analysis focuses on the superradiant plasmon mode, which results from the most attractive interactions along the nanoparticle chain and yields the lowest energy resonance in the spectrum. This superradiant mode redshifts with increasing chain length until an infinite chain limit, where additional increases in chain length cause negligible change in the energy of the superradiant mode. We find that, among plasmonic polymers of equal width comprising nanoparticles with different sizes, the onset of the infinite chain limit and its associated energy are dictated by the number of repeat units and not the overall length of the polymer. The intensities and linewidths of the superradiant mode relative to higher energy resonances, however, differ as the size and number of nanoparticles are varied in the plasmonic polymers studied here. These findings provide general guidelines for engineering the energies, intensities, and line shapes of the collective optical response of plasmonic polymers constructed from nanoparticles with sizes ranging from a few tens to one hundred nanometers.Plasmonic polymers are quasi one-dimensional assemblies of nanoparticles whose optical responses are governed by near-field coupling of localized surface plasmons. Through single particle extinction spectroscopy correlated with electron microscopy, we reveal the effect of the composition of the repeat unit, the chain length, and extent of

  11. Review of Polymer, Dye-Sensitized, and Hybrid Solar Cells

    Directory of Open Access Journals (Sweden)

    S. N. F. Mohd-Nasir

    2014-01-01

    Full Text Available The combination of inorganic nanoparticles semiconductor, conjugated polymer, and dye-sensitized in a layer of solar cell is now recognized as potential application in developing flexible, large area, and low cost photovoltaic devices. Several conjugated low bandgap polymers, dyes, and underlayer materials based on the previous studies are quoted in this paper, which can provide guidelines in designing low cost photovoltaic solar cells. All of these materials are designed to help harvest more sunlight in a wider range of the solar spectrum besides enhancing the rate of charge transfer in a device structure. This review focuses on developing solid-state dye-synthesized, polymer, and hybrid solar cells.

  12. Hybrid Polymer-Network Hydrogels with Tunable Mechanical Response

    OpenAIRE

    Sebastian Czarnecki; Torsten Rossow; Sebastian Seiffert

    2016-01-01

    Hybrid polymer-network gels built by both physical and covalent polymer crosslinking combine the advantages of both these crosslinking types: they exhibit high mechanical strength along with excellent fracture toughness and extensibility. If these materials are extensively deformed, their physical crosslinks can break such that strain energy is dissipated and irreversible fracturing is restricted to high strain only. This mechanism of energy dissipation is determined by the kinetics and therm...

  13. Modelling polymer draft gears

    Science.gov (United States)

    Wu, Qing; Yang, Xiangjian; Cole, Colin; Luo, Shihui

    2016-09-01

    This paper developed a new and simple approach to model polymer draft gears. Two types of polymer draft gears were modelled and compared with experimental data. Impact characteristics, in-train characteristics and frequency responses of these polymer draft gears were studied and compared with those of a friction draft gear. The impact simulations show that polymer draft gears can withstand higher impact speeds than the friction draft gear. Longitudinal train dynamics simulations show that polymer draft gears have significantly longer deflections than friction draft gears in normal train operations. The maximum draft gear working velocities are lower than 0.2 m/s, which are significantly lower than the impact velocities during shunting operations. Draft gears' in-train characteristics are similar to their static characteristics but are very different from their impact characteristics; this conclusion has also been reached from frequency response simulations. An analysis of gangway bridge plate failures was also conducted and it was found that they were caused by coupler angling behaviour and long draft gear deflections.

  14. The structural diversity of artificial genetic polymers

    OpenAIRE

    Anosova, Irina; Kowal, Ewa A.; Dunn, Matthew R.; Chaput, John C.; Van Horn, Wade D.; Egli, Martin

    2015-01-01

    Synthetic genetics is a subdiscipline of synthetic biology that aims to develop artificial genetic polymers (also referred to as xeno-nucleic acids or XNAs) that can replicate in vitro and eventually in model cellular organisms. This field of science combines organic chemistry with polymerase engineering to create alternative forms of DNA that can store genetic information and evolve in response to external stimuli. Practitioners of synthetic genetics postulate that XNA could be used to safeg...

  15. Hybrid Photonic Integration on a Polymer Platform

    OpenAIRE

    Ziyang Zhang; David Felipe; Vasilis Katopodis; Panos Groumas; Christos Kouloumentas; Hercules Avramopoulos; Jean-Yves Dupuy; Agnieszka Konczykowska; Alberto Dede; Antonio Beretta; Antonello Vannucci; Giulio Cangini; Raluca Dinu; Detlef Schmidt; Martin Moehrle

    2015-01-01

    To fulfill the functionality demands from the fast developing optical networks, a hybrid integration approach allows for combining the advantages of various material platforms. We have established a polymer-based hybrid integration platform (polyboard), which provides flexible optical input/ouptut interfaces (I/Os) that allow robust coupling of indium phosphide (InP)-based active components, passive insertion of thin-film-based optical elements, and on-chip attachment of optical fibers. This ...

  16. Structure-property relationships in polymer nanocomposites

    OpenAIRE

    Matveeva, Anna

    2015-01-01

    Tese de Doutoramento em Ciência e Engenharia de Polímeros e Compósitos Carbon nanotubes/ carbon nanofibres (CNTs/CNFs) are considered to be among the most promising reinforcements for improving the mechanical properties of polymers while at the same time offering enhanced electrical and thermal conductivity. Because of their exceptionally high aspect ratio and high surface area in combination with a low density, already small volume fractions can potentially transfer their supe...

  17. Statistical Investigation of Mechanical Characteristics of Polymer Concrete Using Mixture Design of Experiments

    Directory of Open Access Journals (Sweden)

    Daniel Lepădatu

    2007-01-01

    Full Text Available The aim of this paper is to present an approach for developing material models, using a statistical investigation, for analysing the mechanical characteristics of polymer concrete. The experimental studies were realized on polymer concrete prepared of epoxy resin, silica fume and aggregates. The mix combinations were designed based on the mixture design of experiments concept. For each polymer concrete combination the mechanical properties were studied. The results are reported for polymer concrete realized of epoxy resin and silica fume (SUF as filler using Response Surface Methodology (RSM. The effect of each variable on the response was analysed by this advanced method adapted on the study.

  18. Enhancement of Polymer Cytocompatibility by Nanostructuring of Polymer Surface

    OpenAIRE

    Petr Slepička; Nikola Slepičková Kasálková; Lucie Bačáková; Zdeňka Kolská; Václav Švorčík

    2012-01-01

    Polymers with their advantageous physical, chemical, mechanical, and electrical properties and easy manufacturing are widely used in biology, tissue engineering, and medicine, for example, as prosthetic materials. In some cases the polymer usage may be impeded by low biocompatibility of common synthetic polymers. The biocompatibility can be improved by modification of polymer surface, for example, by plasma discharge, irradiation with ionizing radiation, and sometime subsequent grafting with ...

  19. Optimization of Polymer Separation by Gradient Polymer Elution Chromatography

    OpenAIRE

    Liem, Gideon R; Wang, Linda Nien-Hwa

    2013-01-01

    High Performance Liquid Chromatography (HPLC) has been a versatile separation method for polymers for many years. Analysis of different polymers by HPLC is typically done by utilizing the differential solubility of the polymers by mixing a good solvent and an anti-solvent in various compositions. This method is called Gradient Polymer Elution Chromatography (GPEC). While GPEC has been used extensively, it commonly uses a linear gradient to separate components. Linear solvent gradients consume...

  20. Polymer Photovoltaic Cells

    Institute of Scientific and Technical Information of China (English)

    Jianhui Hou; Chunhe Yang; Erjun Zhou; Chang He; Zhan'ao Tan; Youjun He; Yongfang Li

    2005-01-01

    @@ 1Introduction Polymer photovoltaic cells (PPVCs) have attracted much attention recently because of its easy fabrication, low cost and possibility to make flexible devices[1]. PPVC is composed of a conjugated polymer/C60blend layer (photosensitive layer) sandwiched between a transparent ITO electrode and a metal electrode.When a light through ITO electrode irradiates on the photosensitive layer, the photons with appropriate energy will be absorbed by the conjugated polymer (CP) and excitons (electron-hole pair) are produced. The excitons move to the interface of CP/C60 where the electrons transfer to the LUMO of C60 and holes leave on the HOMO of the CP. The separated electrons migrate through the C60 network to and are collected by the metal electrode, and the holes migrate through the CP network to and are collected by the ITO electrode, so that the photocurrent and photovoltage are attained.

  1. 'Stuffed' conducting polymers

    DEFF Research Database (Denmark)

    Winther-Jensen, Bjørn; Chen, Jun; West, Keld;

    2005-01-01

    Conducting polymers (CP) obtained by oxidative polymerization using iron(III) salts shrink when Fe(II) and the excess counter ions are washed out after polymerization. This phenomenon can be used to incorporate active molecules into the CP matrix via their addition to the wash liquid. In the pres......Conducting polymers (CP) obtained by oxidative polymerization using iron(III) salts shrink when Fe(II) and the excess counter ions are washed out after polymerization. This phenomenon can be used to incorporate active molecules into the CP matrix via their addition to the wash liquid....... In the present work we demonstrate this principle on three different CP's: polypyrrole (PPy), poly-terthiophene (PTTh) and poly(3,4-ethylenedioxy thiophene) (PEDT), using ferrocene as a model molecule to be trapped in the polymer films. (c) 2005 Elsevier Ltd. All rights reserved....

  2. Semi-metallic polymers

    DEFF Research Database (Denmark)

    Bubnova, Olga; Khan, Zia Ullah; Wang, Hui;

    2014-01-01

    Polymers are lightweight, flexible, solution-processable materials that are promising for low-cost printed electronics as well as for mass-produced and large-area applications. Previous studies demonstrated that they can possess insulating, semiconducting or metallic properties; here we report...... that polymers can also be semi-metallic. Semi-metals, exemplified by bismuth, graphite and telluride alloys, have no energy bandgap and a very low density of states at the Fermi level. Furthermore, they typically have a higher Seebeck coefficient and lower thermal conductivities compared with metals, thus being...... a Fermi glass to a semi-metal. The high Seebeck value, the metallic conductivity at room temperature and the absence of unpaired electron spins makes polymer semi-metals attractive for thermoelectrics and spintronics....

  3. Protein Polymers and Amyloids

    DEFF Research Database (Denmark)

    Risør, Michael Wulff

    2014-01-01

    that inhibits its target protease through a large conformational change but mutations compromise this function and cause premature structural collapse into hyperstable polymers. Understanding the conformational disorders at a molecular level is not only important for our general knowledge on protein folding...... of this mechanism were investigated through a series of interaction experiments. Despite a very buried location in the native structure, evidence here suggest that the C-terminal tail is labile under slightly destabilizing conditions, providing new detail to this matter. A small infectious polymer unit was also...... constructed and used to show how polymerogenic seeding and polymer propagation might happen inside the body. The locking of central structural elements during α1AT folding or in the native state represents a therapeutic strategy to prevent polymerization. Using Molecular Dynamics simulations, we identified...

  4. Active Polymer Gel Actuators

    Directory of Open Access Journals (Sweden)

    Shuji Hashimoto

    2010-01-01

    Full Text Available Many kinds of stimuli-responsive polymer and gels have been developed and applied to biomimetic actuators or artificial muscles. Electroactive polymers that change shape when stimulated electrically seem to be particularly promising. In all cases, however, the mechanical motion is driven by external stimuli, for example, reversing the direction of electric field. On the other hand, many living organisms can generate an autonomous motion without external driving stimuli like self-beating of heart muscles. Here we show a novel biomimetic gel actuator that can walk spontaneously with a wormlike motion without switching of external stimuli. The self-oscillating motion is produced by dissipating chemical energy of oscillating reaction. Although the gel is completely composed of synthetic polymer, it shows autonomous motion as if it were alive.

  5. Toxicology of Biomedical Polymers

    Directory of Open Access Journals (Sweden)

    P. V. Vedanarayanan

    1987-04-01

    Full Text Available This paper deals with the various types of polymers, used in the fabrication of medical devices, their diversity of applications and toxic hazards which may arise out of their application. The potential toxicity of monomers and the various additives used in the manufacture of biomedical polymers have been discussed along with hazards which may arise out of processing of devices such as sterilization. The importance of quality control and stringent toxicity evaluation methods have been emphasised since in our country, at present, there are no regulations covering the manufacturing and marketing of medical devices. Finally the question of the general and subtle long term systemic toxicity of biomedical polymers have been brought to attention with the suggestion that this question needs to be resolved permanently by appropriate studies.

  6. Coil–globule transition of a polymer involved in excluded-volume interactions with macromolecules

    Energy Technology Data Exchange (ETDEWEB)

    Odagiri, Kenta [School of Network and Information, Senshu University, Kawasaki 214-8580 (Japan); Seki, Kazuhiko, E-mail: k-seki@aist.go.jp [National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 5, Tsukuba, Ibaraki 305-8565 (Japan)

    2015-10-07

    Polymers adopt extended coil and compact globule states according to the balance between entropy and interaction energies. The transition of a polymer between an extended coil state and compact globule state can be induced by changing thermodynamic force such as temperature to alter the energy/entropy balance. Previously, this transition was theoretically studied by taking into account the excluded-volume interaction between monomers of a polymer chain using the partition function. For binary mixtures of a long polymer and short polymers, the coil-globule transition can be induced by changing the concentration of the shorter polymers. Here, we investigate the transition caused by short polymers by generalizing the partition function of the long polymer to include the excluded-volume effect of short polymers. The coil-globule transition is studied as a function of the concentration of mixed polymers by systematically varying Flory’s χ-parameters. We show that the transition is caused by the interplay between the excluded-volume interaction and the dispersion state of short polymers in the solvent. We also reveal that the same results can be obtained by combining the mixing entropy and elastic energy if the volume of a long polymer is properly defined.

  7. Delocalization in polymer models

    CERN Document Server

    Jitomirskaya, S Yu; Stolz, G

    2003-01-01

    A polymer model is a one-dimensional Schroedinger operator composed of two finite building blocks. If the two associated transfer matrices commute, the corresponding energy is called critical. Such critical energies appear in physical models, an example being the widely studied random dimer model. Although the random models are known to have pure-point spectrum with exponentially localized eigenstates for almost every configuration of the polymers, the spreading of an initially localized wave packet is here proven to be at least diffusive for every configuration.

  8. Polymers at cryogenic temperatures

    CERN Document Server

    Fu, Shao-Yun

    2013-01-01

    Kalia and Fu's novel monograph covers cryogenic treatment, properties and applications of cryo-treated polymer materials. Written by numerous international experts, the twelve chapters in this book offer the reader a comprehensive picture of the latest findings and developments, as well as an outlook on the field. Cryogenic technology has seen remarkable progress in the past few years and especially cryogenic properties of polymers are attracting attention through new breakthroughs in space, superconducting, magnetic and electronic techniques. This book is a valuable resource for researchers, educators, engineers and graduate students in the field and at technical institutions.

  9. Shape memory polymer foams

    Science.gov (United States)

    Santo, Loredana

    2016-02-01

    Recent advances in shape memory polymer (SMP) foam research are reviewed. The SMPs belong to a new class of smart polymers which can have interesting applications in microelectromechanical systems, actuators and biomedical devices. They can respond to specific external stimulus changing their configuration and then remember the original shape. In the form of foams, the shape memory behaviour can be enhanced because they generally have higher compressibility. Considering also the low weight, and recovery force, the SMP foams are expected to have great potential applications primarily in aerospace. This review highlights the recent progress in characterization, evaluation, and proposed applications of SMP foams mainly for aerospace applications.

  10. Nanoparticles from Renewable Polymers

    Directory of Open Access Journals (Sweden)

    Frederik Roman Wurm

    2014-07-01

    Full Text Available The use of polymers from natural resources can bring many benefits for novel polymeric nanoparticle systems. Such polymers have a variety of beneficial properties such as biodegradability and biocompatibility, they are readily available on large scale and at low cost. As the amount of fossil fuels decrease, their application becomes more interesting even if characterization is in many cases more challenging due to structural complexity, either by broad distribution of their molecular weights polysaccharides, polyesters, lignin or by complex structure (proteins, lignin. This review summarizes different sources and methods for the preparation of biopolymer-based nanoparticle systems for various applications.

  11. Antibacterial polymer coatings.

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Mollye C.; Allen, Ashley N.; Barnhart, Meghan; Tucker, Mark David; Hibbs, Michael R.

    2009-09-01

    A series of poly(sulfone)s with quaternary ammonium groups and another series with aldehyde groups are synthesized and tested for biocidal activity against vegetative bacteria and spores, respectively. The polymers are sprayed onto substrates as coatings which are then exposed to aqueous suspensions of organisms. The coatings are inherently biocidal and do not release any agents into the environment. The coatings adhere well to both glass and CARC-coated coupons and they exhibit significant biotoxicity. The most effective quaternary ammonium polymers kills 99.9% of both gram negative and gram positive bacteria and the best aldehyde coating kills 81% of the spores on its surface.

  12. Edible Polymers: Challenges and Opportunities

    Directory of Open Access Journals (Sweden)

    Subhas C. Shit

    2014-01-01

    Full Text Available Edible polymers have established substantial deliberation in modern eons because of their benefits comprising use as edible materials over synthetic polymers. This could contribute to the reduction of environmental contamination. Edible polymers can practically diminish the complexity and thus improve the recyclability of materials, compared to the more traditional non-environmentally friendly materials and may be able to substitute such synthetic polymers. A synthetic hydrogel polymer unlocked a new possibility for development of films, coatings, extrudable pellets, and synthetic nanopolymers, particularly designed for medical, agricultural, and industrial fields. Edible polymers offer many advantages for delivering drugs and tissue engineering. Edible polymer technology helps food industries to make their products more attractive and safe to use. Novel edible materials have been derived from many natural sources that have conventionally been regarded as discarded materials. The objective of this review is to provide a comprehensive introduction to edible polymers by providing descriptions in terms of their origin, properties, and potential uses.

  13. Composite solid polymer electrolyte membranes

    Energy Technology Data Exchange (ETDEWEB)

    Formato, Richard M. (Shrewsbury, MA); Kovar, Robert F. (Wrentham, MA); Osenar, Paul (Watertown, MA); Landrau, Nelson (Marlborough, MA); Rubin, Leslie S. (Newton, MA)

    2001-06-19

    The present invention relates to composite solid polymer electrolyte membranes (SPEMs) which include a porous polymer substrate interpenetrated with an ion-conducting material. SPEMs of the present invention are useful in electrochemical applications, including fuel cells and electrodialysis.

  14. Polymer-solvent molecular compounds

    CERN Document Server

    Guenet, Jean-Michel

    2010-01-01

    Crystallisable polymers represent a large share of the polymers used for manufacturing a wide variety of objects, and consequently have received continuous attention from scientists these past 60 years. Molecular compounds from crystallisable polymers, particularly from synthetic polymers, are receiving growing interest due to their potential application in the making of new materials such as multiporous membranes capable of capturing large particles as well as small pollutant molecules. The present book gives a detailed description of these promising systems. The first chapter

  15. Shape memory polymer medical device

    Science.gov (United States)

    Maitland, Duncan; Benett, William J.; Bearinger, Jane P.; Wilson, Thomas S.; Small, IV, Ward; Schumann, Daniel L.; Jensen, Wayne A.; Ortega, Jason M.; Marion, III, John E.; Loge, Jeffrey M.

    2010-06-29

    A system for removing matter from a conduit. The system includes the steps of passing a transport vehicle and a shape memory polymer material through the conduit, transmitting energy to the shape memory polymer material for moving the shape memory polymer material from a first shape to a second and different shape, and withdrawing the transport vehicle and the shape memory polymer material through the conduit carrying the matter.

  16. Polymer's anchoring behavior in liquid crystal cells

    Science.gov (United States)

    Cui, Yue

    The current dissertation mainly discusses about the polymers anchoring behavior in liquid crystal cells in two aspects: surface interaction and bulk interaction. The goal of the research is to understand the fundamental physics of anchoring strength and apply the knowledge to liquid crystal display devices. Researchers proposed two main contributors to the surface anchoring strength: the micro grooves generated by external force and the polymer chain's alignment. Both of them has experimental proofs. In the current study, explorations were made to understand the mechanisms of surface anchoring strength and easy axis of surface liquid crystal provided by rubbed polymer alignment layer. The work includes not only the variation of the alignment layer itself such as thickness(Chapter 3) and polymer side chain (Chapter 5), but also the variation of external conditions such as temperature (Chapter 4) and rubbing condition (Chapter 6). To determine the polar and azimuthal anchoring strengths, Rapini-Papoular's expression was applied. However, it was discovered that higher order terms may be required in order to fit the experimental result or theoretically predict unique anchoring behaviors (Chapter 2, Chapter 6). SEM and AFM technologies were introduced to gather the actual structures of polymer alignment layer and extrapolate the alignment of liquid crystal in a micro scale. The result shows that the anchoring strength can be adjusted by the layer thickness, side chain structure, while the easy axis direction can be adjusted by a second rubbing direction. In addition, different anchoring conditions combined with liquid crystal's elastic energy can generate quite different forms of liquid crystals (Chapter 7). In the study of bulk alignment, the main contrition from the current dissertation is applying the understanding of anchoring behavior to optimizing actual switchable devices. Conventional PDLC performance can be tuned with the knowledge of the polymer and the liquid

  17. Self-Assembled Conjugated Polymer Nanometer Scale Devices

    Institute of Scientific and Technical Information of China (English)

    Wenping Hu; Hiroshi Nakashima; Keiichi Torimitsu; Yunqi Liu; Daoben Zhu

    2005-01-01

    @@ 1Introduction Nanometer scale devices, as the next generation devices of electronics, have got a worldwide attention and rapid development recently. Simultaneously, conjugated polymers have been applied in organic electronics successfully because of their outstanding electronic-photonic properties. However, as far as we know few reports have dealt with the fabrication of nanometer scale devices by using conjugated polymers, although the combination of nanometer scale devices and polymers will not only extend conjugated polymers to Nanoelectronics, but also excavate the behaviors of polymer molecules at nano-molecular level, such as the electron transport through polymer molecules. One reason for this case is due to the lack of rigidity for most polymers.It results in the failure to bridge them between electrodes or to stand on substrates, therefore, fails to be characterized by scanning probe microscopy. Another reason is that the non-functionalized end-group of most polymers is impossible to graft on substrates through chemical bonds. Here, we introduce a self-assembled conjugated polymer can be used to fabricate nanodevices by self-assembly. The conjugated polymer is a derivative of poly(p-phenyleneethynylene)s (PPE) with thioacetyl end groups (Fig. 1). In general, it is known that for self-assembling ideal nanojunctions the materials should possess: a) conductivity, b) rigidity (for wiring and bridging between electrodes), and c) connectivity (for covalent attachment to metallic or semiconductor solid surfaces). PPE provides good conductivity owing to its special π-conjugated configuration. It is also believed that in principle PPE molecules possess rigidity because of the presence of the triple bond in their molecules,which prevents the rotation of adjacent phenyl rings with respect to each other.

  18. In Situ Nanopressing: A General Approach to Robust Nanoparticles-Polymer Surface Structures

    Science.gov (United States)

    Zhang, Xiaojie; He, Junhui; Jin, Binbin

    2016-01-01

    We report a novel, facile and general approach, in situ nanopressing, to integrate nanoparticles and polymers in a thin film configuration, where both nanoparticles exposure and film robustness are indispensable for applications. By simply pressing silica nanoparticles into a polymer thin film under an external force, we successfully attained a nanoparticles-polymer thin film, where the silica nanoparticles were partly embedded in the polymer thin film. The outstanding characteristic of easy-to-fabricate nanoparticles-polymer thin films combined the properties of both materials, giving excellent antireflective and antifogging properties, as well as enhanced the robustness of composite thin film. This in situ nanopressing may not only provide an alternative to meet the challenge of constructing mechanically robust nanoparticles-polymer thin films that require nanoparticles on the film surface, but also enrich the methodology to integrate nanoparticles and polymers. PMID:27642153

  19. Immobilization of enzyme on a polymer surface

    Science.gov (United States)

    Shen, Lei; Cheng, Kenneth Chun Kuen; Schroeder, McKenna; Yang, Pei; Marsh, E. Neil G.; Lahann, Joerg; Chen, Zhan

    2016-06-01

    We successfully immobilized enzymes onto polymer surfaces via covalent bonds between cysteine groups of the enzyme and dibromomaleimide functionalities present at the polymer surface. In this work, we used nitroreductase (NfsB) as a model enzyme molecule. The polymers were prepared by chemical vapor deposition (CVD) polymerization, resulting in surfaces with dibromomaleimide groups. NfsB variants were engineered so that each NfsB molecule only has one cysteine group on the enzyme surface. Two different NfsB constructs were studied, with cysteines at the positions of H360 and V424, respectively. A combination of sum frequency generation (SFG) vibrational and attenuated total reflectance Fourier transformed infrared (ATR-FTIR) spectroscopies were used to deduce the orientation of the immobilized enzymes on the surface. It was found that the orientation of the immobilized enzymes is controlled by the position of the cysteine residue in the protein. The NfsB H360C construct exhibited a similar orientational behavior on the polymer surface as compared to that on the self-assembled monolayer surface, but the NsfB V424C construct showed markedly different orientations on the two surfaces.

  20. Nanomembranes and Nanofibers from Biodegradable Conducting Polymers

    Directory of Open Access Journals (Sweden)

    Jordi Puiggalí

    2013-09-01

    Full Text Available This review provides a current status report of the field concerning preparation of fibrous mats based on biodegradable (e.g., aliphatic polyesters such as polylactide or polycaprolactone and conducting polymers (e.g., polyaniline, polypirrole or polythiophenes. These materials have potential biomedical applications (e.g., tissue engineering or drug delivery systems and can be combined to get free-standing nanomembranes and nanofibers that retain the better properties of their corresponding individual components. Systems based on biodegradable and conducting polymers constitute nowadays one of the most promising solutions to develop advanced materials enable to cover aspects like local stimulation of desired tissue, time controlled drug release and stimulation of either the proliferation or differentiation of various cell types. The first sections of the review are focused on a general overview of conducting and biodegradable polymers most usually employed and the explanation of the most suitable techniques for preparing nanofibers and nanomembranes (i.e., electrospinning and spin coating. Following sections are organized according to the base conducting polymer (e.g., Sections 4–6 describe hybrid systems having aniline, pyrrole and thiophene units, respectively. Each one of these sections includes specific subsections dealing with applications in a nanofiber or nanomembrane form. Finally, miscellaneous systems and concluding remarks are given in the two last sections.

  1. Magnetic field control of fluorescent polymer nanorods

    International Nuclear Information System (INIS)

    Nanoscale objects that combine high luminescence output with a magnetic response may be useful for probing local environments or manipulating objects on small scales. Ideally, these two properties would not interfere with each other. In this paper, we show that a fluorescent polymer host material can be doped with high concentrations of 20–30 nm diameter magnetic γ-Fe2O3 particles and then formed into 200 nm diameter nanorods using porous anodic alumina oxide templates. Two different polymer hosts are used: the conjugated polymer polydioctylfluorene and also polystyrene doped with the fluorescent dye Lumogen Red. Fluorescence decay measurements show that 14% by weight loading of the γ-Fe2O3 nanoparticles quenches the fluorescence of the polydioctylfluorene by approximately 33%, but the polystyrene/Lumogen Red fluorescence is almost unaffected. The three-dimensional orientation of both types of nanorods can be precisely controlled by the application of a moderate strength (∼0.1 T) external field with sub-second response times. Transmission electron microscope images reveal that the nanoparticles cluster in the polymer matrix, and these clusters may serve both to prevent fluorescence quenching and to generate the magnetic moment that rotates in response to the applied magnetic field.

  2. Nanopatterned polymer brushes by reactive writing

    Science.gov (United States)

    Nawroth, Jonas F.; Neisser, Claudia; Erbe, Artur; Jordan, Rainer

    2016-03-01

    Polymer brush patterns were prepared by a combination of electron beam induced damage in self-assembled monolayers (SAMs), creating a stable carbonaceous deposit, and consecutive self-initiated photografting and photopolymerization (SIPGP). This newly applied technique, reactive writing (RW), is investigated with 1H,1H,2H,2H-perfluorooctyltriethoxysilane SAM (PF-SAM) on silicon oxide, which, when modified by RW, can be selectively functionalized by SIPGP. With the monomer N,N-dimethylaminoethyl methacrylate (DMAEMA), we demonstrate the straightforward formation of polymer brush gradients and single polymer lines of sub-100 nm lateral dimensions, with high contrast to the PF-SAM background. The lithography parameters acceleration voltage, irradiation dose, beam current and dwell time were systematically varied to identify the optimal conditions for the maximum conversion of the SAM into a carbonaceous deposit. The results of this approach were compared to patterns prepared by carbon templating (CT) under analogous conditions, revealing a dwell time dependency, which differs from earlier reports. This new technique expands the range of CT by giving the opportunity to not only vary the chemistry of the created polymer patterns with monomer choice but also vary the chemistry of the surrounding substrate.

  3. ASPECTS OF THERMODYNAMICS OF POLYMER MIXTURES

    Institute of Scientific and Technical Information of China (English)

    CHAI Zhikuan

    1987-01-01

    In this brief review article some aspects of the thermodynamics of polymer mixtures are discussed,mainly based on the author's research. The studies of poly (methyl methacrylate)/chlorinated polyethylene (CPE), poly (butyl acrylate)/CPE and CPE/CPE (different chlorine content) mixture verify the "dissimilarity" and "similarity" principles for predicting miscibility of polymer mixtures. The sign of heat of mixing of oligomeric analogues is not sufficient in predicting the miscibility. The Flory equation of state theory has been applied to simulate the phase boundaries of polymer mixtures. The empirical entropy parameter Q12 plays an important role in the calculation, this reduces the usefulness of the theory. With energy parameter X12 ≠ 0 and Q12 ≠ 0 the spinodals so calculated are reasonable compared to experiments.A hole model was suggested for the statistics of polymer mixtures. The new hole theory combines the features of both the Flory equation of state theory and the Sanchez lattice fluid theory and can be reduced to them under some conditions.

  4. Polymer Thermoelectric Generators: Device Considerations

    Science.gov (United States)

    Yee, Shannon

    2014-03-01

    Recent control of the transport properties in polymers has encouraged the development of polymer thermoelectric (TE) devices. Polymer TEs are thought to be less expensive and more scalable than their inorganic counterparts. The cost of the raw material is less and polymer TEs can leverage the large areal manufacturing technique established by the plastics industry. Additionally, while the overall ZT of polymer TEs appears attractive, individual polymer properties have a very different scale than their inorganic counterparts (i.e., the thermal conductivity and electrical conductivity are approximately one and two orders of magnitude smaller, respectively). Furthermore, the majority of TE measurements on polymers have been limited to thin-films where traditional TE materials are measured in bulk. So why should it be expected that polymer TE devices resemble traditional TE devices? Given the uniqueness of polymers, different device architectures are proposed that can leverage the unique strengths of polymer films. It will be shown that by logically considering device requirements, new polymer TE devices have non-linear features that are more attractive than linear inorganic TE devices. This leads to very different device optimizations that favor polymer TEs.

  5. Adsorption theory for polydisperse polymers.

    NARCIS (Netherlands)

    Roefs, S.P.F.M.; Scheutjens, J.M.H.M.; Leermakers, F.A.M.

    1994-01-01

    Most polymers are polydisperse. We extend the self-consistent field polymer adsorption theory due to Scheutjens and Fleer to account for an arbitrary polymer molecular weight distribution with a cutoff chain length Nmax. In this paper, the treatment is restricted to homopolymers. For this case a ver

  6. Polymer modification via. cluster formation

    International Nuclear Information System (INIS)

    Ion beam treatment studies have been carried out to investigate the potential for improvements in conductivity properties of the polymers. Change in polymer stoichiometry were characterised by investigating into the carbon clusters formed along the latent tracks of energetic ions in polymers. Here we present some new results which have been derived from UV-Vis spectroscopic examinations. (author)

  7. Aerogel/polymer composite materials

    Science.gov (United States)

    Williams, Martha K. (Inventor); Smith, Trent M. (Inventor); Fesmire, James E. (Inventor); Roberson, Luke B. (Inventor); Clayton, LaNetra M. (Inventor)

    2010-01-01

    The invention provides new composite materials containing aerogels blended with thermoplastic polymer materials at a weight ratio of aerogel to thermoplastic polymer of less than 20:100. The composite materials have improved thermal insulation ability. The composite materials also have better flexibility and less brittleness at low temperatures than the parent thermoplastic polymer materials.

  8. Viscoelastic Properties of Polymer Blends

    Science.gov (United States)

    Hong, S. D.; Moacanin, J.; Soong, D.

    1982-01-01

    Viscosity, shear modulus and other viscoelastic properties of multicomponent polymer blends are predicted from behavior of individual components, using a mathematical model. Model is extension of two-component-blend model based on Rouse-Bueche-Zimm theory of polymer viscoelasticity. Extension assumes that probabilities of forming various possible intracomponent and intercomponent entanglements among polymer molecules are proportional to relative abundances of components.

  9. Nonlinear microstructured polymer optical fibres

    DEFF Research Database (Denmark)

    Frosz, Michael Henoch

    is potentially the case for microstructured polymer optical fibres (mPOFs). Another advantage is that polymer materials have a higher biocompatibility than silica, meaning that it is easier to bond certain types of biosensor materials to a polymer surface than to silica. As with silica PCFs, it is difficult...

  10. Multifunctional Nanotube Polymer Nanocomposites for Aerospace Applications: Adhesion between SWCNT and Polymer Matrix

    Science.gov (United States)

    Park, Cheol; Wise, Kristopher E.; Kang, Jin Ho; Kim, Jae-Woo; Sauti, Godfrey; Lowther, Sharon E.; Lillehei, Peter T.; Smith, Michael W.; Siochi, Emilie J.; Harrison, Joycelyn S.; Jordan, Kevin

    2008-01-01

    Multifunctional structural materials can enable a novel design space for advanced aerospace structures. A promising route to multifunctionality is the use of nanotubes possessing the desired combination of properties to enhance the characteristics of structural polymers. Recent nanotube-polymer nanocomposite studies have revealed that these materials have the potential to provide structural integrity as well as sensing and/or actuation capabilities. Judicious selection or modification of the polymer matrix to promote donor acceptor and/or dispersion interactions can improve adhesion at the interface between the nanotubes and the polymer matrix significantly. The effect of nanotube incorporation on the modulus and toughness of the polymer matrix will be presented. Very small loadings of single wall nanotubes in a polyimide matrix yield an effective sensor material that responds to strain, stress, pressure, and temperature. These materials also exhibit significant actuation in response to applied electric fields. The objective of this work is to demonstrate that physical properties of multifunctional material systems can be tailored for specific applications by controlling nanotube treatment (different types of nanotubes), concentration, and degree of alignment.

  11. Segmented conjugated polymers

    Indian Academy of Sciences (India)

    G Padmanaban; S Ramakrishnan

    2003-08-01

    Segmented conjugated polymers, wherein the conjugation is randomly truncated by varying lengths of non-conjugated segments, form an interesting class of polymers as they not only represent systems of varying stiffness, but also ones where the backbone can be construed as being made up of chromophores of varying excitation energies. The latter feature, especially when the chromophores are fluorescent, like in MEHPPV, makes these systems particularly interesting from the photophysics point of view. Segmented MEHPPV- samples, where x represents the mole fraction of conjugated segments, were prepared by a novel approach that utilizes a suitable precursor wherein selective elimination of one of the two eliminatable groups is affected; the uneliminated units serve as conjugation truncations. Control of the composition x of the precursor therefore permits one to prepare segmented MEHPPV- samples with varying levels of conjugation (elimination). Using fluorescence spectroscopy, we have seen that even in single isolated polymer chains, energy migration from the shorter (higher energy) chromophores to longer (lower energy) ones occurs – the extent of which depends on the level of conjugation. Further, by varying the solvent composition, it is seen that the extent of energy transfer and the formation of poorly emissive inter-chromophore excitons are greatly enhanced with increasing amounts of non-solvent. A typical S-shaped curve represents the variation of emission yields as a function of composition suggestive of a cooperative collapse of the polymer coil, reminiscent of conformational transitions seen in biological macromolecules.

  12. Phosphazene Polymers Containing Carborane

    Science.gov (United States)

    Fewell, L. L.; Parker, J. A.; Basi, R. J.

    1986-01-01

    Addition of carborane increases thermal stability. Carborane-substituted polyphosphazenes prepared by thermal polymerization of phenylcarbonyl-pentachlorocyclotriphosphazene followed by reaction with sodium trifluoroethoxide to replace remaining chlorine atoms with trifluoroethoxy groups. Improved polymers offer high char yields and resistance to hydrolysis.

  13. Cyclic polymers from alkynes

    Science.gov (United States)

    Roland, Christopher D.; Li, Hong; Abboud, Khalil A.; Wagener, Kenneth B.; Veige, Adam S.

    2016-08-01

    Cyclic polymers have dramatically different physical properties compared with those of their equivalent linear counterparts. However, the exploration of cyclic polymers is limited because of the inherent challenges associated with their synthesis. Conjugated linear polyacetylenes are important materials for electrical conductivity, paramagnetic susceptibility, optical nonlinearity, photoconductivity, gas permeability, liquid crystallinity and chain helicity. However, their cyclic analogues are unknown, and therefore the ability to examine how a cyclic topology influences their properties is currently not possible. We have solved this challenge and now report a tungsten catalyst supported by a tetraanionic pincer ligand that can rapidly polymerize alkynes to form conjugated macrocycles in high yield. The catalyst works by tethering the ends of the polymer to the metal centre to overcome the inherent entropic penalty of cyclization. Gel-permeation chromatography, dynamic and static light scattering, viscometry and chemical tests are all consistent with theoretical predictions and provide unambiguous confirmation of a cyclic topology. Access to a wide variety of new cyclic polymers is now possible by simply choosing the appropriate alkyne monomer.

  14. Metal-Polymer Nanocomposites

    Science.gov (United States)

    Nicolais, Luigi; Carotenuto, Gianfranco

    2004-09-01

    A unique guide to an essential area of nanoscience Interest in nano-sized metals has increased greatly due to their special characteristics and suitability for a number of advanced applications. As technology becomes more refined-including the ability to effectively manipulate and stabilize metals at the nanoscale-these materials present ever-more workable solutions to a growing range of problems. Metal-Polymer Nanocomposites provides the first guide solely devoted to the unique properties and applications of this essential area of nanoscience. It offers a truly multidisciplinary approach, making the text accessible to readers in physical, chemical, and materials science as well as areas such as engineering and topology. The thorough coverage includes: * The chemical and physical properties of nano-sized metals * Different approaches to the synthesis of metal-polymer nanocomposites (MPN) * Advanced characterization techniques and methods for study of MPN * Real-world applications, including color filters, polarizers, optical sensors, nonlinear optical devices, and more * An extensive list of references on the topics covered A unique, cutting-edge resource for a vital area of nanoscience development, Metal-Polymer Nanocomposites is an invaluable text for students and practitioners of materials science, engineering, polymer science, chemical engineering, electrical engineering, and optics.

  15. Mechanically Invisible Polymer Coatings

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a composition comprising encapsulated particles in a polymeric material. The composition comprises a continuous phase and a discontinuous phase incorporated therein, wherein the continuous phase comprises a first polymeric material and wherein the discontinuous ph...... invisible polymer coatings....

  16. Conformational properties of polymers

    Indian Academy of Sciences (India)

    A R Singh; D Giri; S Kumar

    2008-08-01

    We discuss exact enumeration technique and its application to polymers and biopolymers. Using this method one can obtain phase diagram in thermodynamic limit. The method works quite well in describing the outcomes of single molecule force spectroscopy results where finite size effects play a crucial role.

  17. Self-sterilizing polymers

    Science.gov (United States)

    Tulis, J. J.; Daley, D. J.; Phillips, G. B.

    1973-01-01

    Addition of approximately 1% paraformaldehyde to room-temperature-vulcanizing potting polymer results in effective, controllable germicide. When heated above ambient temperatures, paraformaldehyde releases dry formaldehyde, which can penetrate enclosed areas and packages, will not damage material, and leaves no permanent residue.

  18. Transferases in Polymer Chemistry

    NARCIS (Netherlands)

    van der Vlist, Jeroen; Loos, Katja; Palmans, ARA; Heise, A

    2010-01-01

    Transferases are enzymes that catalyze reactions in which a group is transferred from one compound to another. This makes these enzymes ideal catalysts for polymerization reactions. In nature, transferases are responsible for the synthesis of many important natural macromolecules. In synthetic polym

  19. Dynamics of Polaron at Polymer/Polymer Interface

    Institute of Scientific and Technical Information of China (English)

    DI Bing; MENG Yan; AN Zhong; LI You-Cheng

    2008-01-01

    The migration of a polaron at polymer/polymer interface is believed to be of fundamental importance for the transport and light-emitting properties of conjugated polymer-based light emitting diodes.Based on the onedimensional tight-binding Su-Schrieffer-Heeger(SSH)model,we have investigated polaron dynamics in a onedimensional polymer/polymer system by using a nonadiabatic evolution method.In particular,we focus on how a polaron migrates through the conjugated polymer/polymer interface in the presence of external electric field.The results show that the migration of polaron at the interface depends sensitively on the hopping integrals,the potential barrier induced by the energy mismatch,and the strength of applied electric field which increases the polaron kinetic energy.

  20. A review of the fundamentals of polymer-modified asphalts: Asphalt/polymer interactions and principles of compatibility.

    Science.gov (United States)

    Polacco, Giovanni; Filippi, Sara; Merusi, Filippo; Stastna, George

    2015-10-01

    the specification and techniques proposed to quantify the storage stability, state-of-the-art knowledge about the internal structure and morphology of polymer-modified asphalts is presented. Moreover, the chemical, physical, and processing solutions suggested in the scientific and patent literature to improve storage stability are extensively discussed, with particular attention to an emerging class of asphalt binders in which the technologies of polymer-modified asphalts and polymer nanocomposites are combined. These polymer-modified asphalt nanocomposites have been introduced less than ten years ago and still do not meet the requirements of industrial practice, but they may constitute a solution for both the performance and storage requirements. PMID:26277208

  1. A novel route for fabricating metal-polymer composite nanoparticles with phase-separated structures.

    Science.gov (United States)

    Yabu, Hiroshi; Koike, Kazutaka; Motoyoshi, Kiwamu; Higuchi, Takeshi; Shimomura, Masatsugu

    2010-07-15

    Au nanoparticles (NPs) and polymer composite particles with phase-separation structures were prepared based on phase separation structures. Au NPs were successfully synthesized in amphiphilic block-copolymer micelles, and then composite particles were formed by a simple solvent evaporation process from Au NPs and polymer solution. The phase separated structures (Janus and Core-shell) were controlled by changing the combination of polymers having differing hydrophobicity. PMID:21567522

  2. Inorganic-organic hybrid polymers: Solution-processible coating materials for defined surface functionalization

    OpenAIRE

    Keßler, Daniel

    2009-01-01

    A new class of inorganic-organic hybrid polymers could successfully been prepared by the combination of different polymerization techniques. The access to a broad range of organic polymers incorporated into the hybrid polymer was realized using two independent approaches.rnIn the first approach a functional poly(silsesquioxane) (PSSQ) network was pre-formed, which was capable to initiate a controlled radical polymerization to graft organic vinyl-type monomers from the PSSQ precursor. As contr...

  3. Formulation Development and Evaluation of Innovative Two-Polymer (SR-2P) Bioadhesive Vaginal Gel

    OpenAIRE

    Podaralla, Satheesh; Alt, Carsten; Shankar, Gita N.

    2014-01-01

    The main objective of this investigation was to study the feasibility of developing a vaginal bioadhesive microbicide using a SRI’s proprietary two-polymer gel platform (SR-2P). Several formulations were prepared with different combinations of temperature-sensitive polymer (Pluronic® F-127) and mucoadhesive polymer (Noveon® AA-1), producing gels of different characteristics. Prototype polymeric gels were evaluated for pH, osmolality, buffering capacity, and viscosity under simulated vaginal s...

  4. Performance of Polymer Modified Mortar with Different Dosage of Polymeric Modifier

    OpenAIRE

    Ganesan Shankar; Othuman Mydin Md Azree; Sani Norazmawati Md.; Che Ani Adi Irfan

    2014-01-01

    Polymer modified mortar system is defined as hydraulic cement combined at the time of mixing with organic polymers that are dispersed or re-dispersed in water, with or without aggregates. The compressive strength and flexural strength of polymer modified mortar obtained at early age are low and it required prolong curing period for the strength enhancement. In order to enhance the mechanical properties of cementitious mixture as well as its durability, hybridization of polymeric modifiers are...

  5. Design of electrically conducting polymer hybrid composites based on polyvinyl chloride and polyethylene

    OpenAIRE

    Kuryptya, Yaroslav; Sova, Nadiya; Savchenko, Bohdan; Slieptsov, Aleksander; Plavan, Viktoriia

    2016-01-01

    Interest to electrically conducting polymer composite materials in recent times has grown considerably, which is associated with the design of new branches of science and technology. The existing analogues are different in the complexity of production and high cost. One of the ways of solving the problem may be designing polymer composite materials with a combined filler. The research was carried out on creating electrically conducting hybrid polymer composites, based on emulsion polyvinyl ch...

  6. Nanoparticle-assisted high photoconductive gain in polymer/fullerene matrix

    OpenAIRE

    Chen, Hsiang-Yu; Lo, Michael K. F.; Yang, Guanwen; Harold G. Monbouquette; Yang, Yang

    2008-01-01

    Polymer/inorganic nanocrystal composites1–10 offer an attractive means to combine the merits of organic and inorganic materials into novel electronic and photonic systems. However, many applications of these composites are limited by the solubility11 and distribution of nanocrystals (NCs) in polymer matrices. Here, a high photoconductive gain has been achieved by blending cadmium telluride (CdTe) nanoparticles (NPs) into a polymer/fullerene matrix followed by a solvent annealing12 process. Th...

  7. POLYMER ELECTROLYTE MEMBRANE FUEL CELLS

    DEFF Research Database (Denmark)

    2001-01-01

    thermoplastic polymers for high temperature polymer electrolyte fuel cells have also been developed. Miscible blends are used for solution casting of polymer membranes (solid electrolytes). High conductivity and enhanced mechanical strength were obtained for the blend polymer solid electrolytes....... With the thermally resistant polymer, e.g., polybenzimidazole or a mixture of polybenzimidazole and other thermoplastics as binder, the carbon-supported noble metal catalyst is tape-cast onto a hydrophobic supporting substrate. When doped with an acid mixture, electrodes are assembled with an acid doped solid...

  8. Frictional properties of confined polymers

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Samoilov, Vladimir N; Persson, Bo N J

    2008-01-01

    We present molecular dynamics friction calculations for confined hydrocarbon solids with molecular lengths from 20 to 1400 carbon atoms. Two cases are considered: a) polymer sliding against a hard substrate, and b) polymer sliding on polymer. In the first setup the shear stresses are relatively...... independent of molecular length. For polymer sliding on polymer the friction is significantly larger, and dependent on the molecular chain length. In both cases, the shear stresses are proportional to the squeezing pressure and finite at zero load, indicating an adhesional contribution to the friction force...

  9. A Modified Polymer from Polyacrylonitrile

    Directory of Open Access Journals (Sweden)

    Indra Bajaj

    1969-07-01

    Full Text Available Polyacrylonitrile has been modified by introducing thioamide groups (-CSNH/sub 2/ in place of nitride groups (-CN in the chain by passing dry H/sub 2/ S gas through a 5% solution of the polymer in N-N dimethylformamide. The modified polymer is soluble in acetone. X-ray study revealed the complete loss of crystallinity in the modified polymer. Infra-red spectrum of the polymer film shows strong absorption bands at 3390 cm/sup 1/, 2273 cm/sup 1/ and 1667 cm/sup 1/ indicating the presence of both thioamide and nitride groups in the polymer chain.

  10. Conducting Polymers for Neutron Detection

    Energy Technology Data Exchange (ETDEWEB)

    Kimblin, Clare; Miller, Kirk; Vogel, Bob; Quam, Bill; McHugh, Harry; Anthony, Glen; Mike, Grover

    2007-12-01

    Conjugated polymers have emerged as an attractive technology for large-area electronic applications. As organic semiconductors, they can be used to make large-area arrays of diodes or transistors using fabrication techniques developed for polymer coatings, such as spraying and screen-printing. We have demonstrated both neutron and alpha detection using diodes made from conjugated polymers and have done preliminary work to integrate a boron carbide layer into the conventional polymer device structure to capture thermal neutrons. The polymer devices appear to be insensitive to gamma rays, due to their small physical thickness and low atomic number.

  11. In situ preparation of Nanoparticles/polymer composites

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Nanoparticle (NP) is the matter between molecule and bulk material. It has attracted much attention in catalysis, optoelectronics and biology due to its unique physical and chemical properties. Incorporation of these NPs into the polymer matrix is one of the best methods to display their special functions, which not only stabilize the NPs but also realize the functional assembly of NPs and polymers. However, reali- zation of this idea depends largely on the compatibility of NPs and polymers as well as the interaction between them. Therefore, many methods have been developed to prepare the composites of NPs and polymers in order to obtain the function ex- pected. In this review, we mainly focus on the combination of in situ method with other methods to synthesize different functional one-dimension, two-dimension as well as bulk composites, which has been recently developed by our group. The most striking character of our method is the excellent compatibility between NPs and polymers which ensures a homogeneous distribution of NPs in the polymer matrix. The existence of the polymer network makes the NPs more stable, and is significant for displaying their functions.

  12. In situ preparation of Nanoparticles/polymer composites

    Institute of Scientific and Technical Information of China (English)

    SUN HaiZhu; YANG Bai

    2008-01-01

    Nanoparticle (NP) is the matter between molecule and bulk material. It has attracted much attention in catalysis, optoelectronics and biology due to its unique physical and chemical properties. Incorporation of these NPs into the polymer matrix is one of the best methods to display their special functions, which not only stabilize the NPs but also realize the functional assembly of NPs and polymers. However, reali-zation of this idea depends largely on the compatibility of NPs and polymers as well as the interaction between them. Therefore, many methods have been developed to prepare the composites of NPs and polymers in order to obtain the function ex-pected. In this review, we mainly focus on the combination of in situ method with other methods to synthesize different functional one-dimension, two-dimension as well as bulk composites, which has been recently developed by our group. The most striking character of our method is the excellent compatibility between NPs and polymers which ensures a homogeneous distribution of NPs in the polymer matrix. The existence of the polymer network makes the NPs more stable, and is significant for displaying their functions.

  13. Molecular Design of Synthetic Biodegradable Polymers as Cell Scaffold Materials

    Institute of Scientific and Technical Information of China (English)

    WANG Shen-guo; WAN Yu-qing; CAI Qing; HE Bin; CHEN Wen-na

    2004-01-01

    Poly(lactic acid) and its copolymers are regarded as the most useful biomaterials. The good biocompatibility, biodegradability and mechanical properties of them make the synthetic biodegradable polymers have primary application to tissue engineering. The advantages and disadvantages of the synthetic biodegradable polymers as cell scaffold materials are evaluated. This article reviews the modification of polylactide-family aliphatic polymers to improve the cell affinity when the polymers are used as cell scaffolds. We have developed four main approaches: to modify polyester cell scaffolds in combination of plasma treating and collagen coating; to introduce hydrophilic segments into aliphatic polyester backbones; to introduce pendant functional groups into polyester chains; to modify polyester with dextran. The results of the cell cultures prove that the approaches mentioned above have improved the cell affinity of the polyesters and have modulated cell function such as adhesion, proliferation and migration.

  14. Microbial production of building block chemicals and polymers.

    Science.gov (United States)

    Lee, Jeong Wook; Kim, Hyun Uk; Choi, Sol; Yi, Jongho; Lee, Sang Yup

    2011-12-01

    Owing to our increasing concerns on the environment, climate change, and limited natural resources, there has recently been considerable effort exerted to produce chemicals and materials from renewable biomass. Polymers we use everyday can also be produced either by direct fermentation or by polymerization of monomers that are produced by fermentation. Recent advances in metabolic engineering combined with systems biology and synthetic biology are allowing us to more systematically develop superior strains and bioprocesses for the efficient production of polymers and monomers. Here, we review recent trends in microbial production of building block chemicals that can be subsequently used for the synthesis of polymers. Also, recent successful cases of direct one-step production of polymers are reviewed. General strategies for the production of natural and unnatural platform chemicals are described together with representative examples. PMID:21420291

  15. Polymer-metal hybrid transparent electrodes for flexible electronics

    Science.gov (United States)

    Kang, Hongkyu; Jung, Suhyun; Jeong, Soyeong; Kim, Geunjin; Lee, Kwanghee

    2015-01-01

    Despite nearly two decades of research, the absence of ideal flexible and transparent electrodes has been the largest obstacle in realizing flexible and printable electronics for future technologies. Here we report the fabrication of ‘polymer-metal hybrid electrodes’ with high-performance properties, including a bending radius 95% and a sheet resistance plastic substrates using an amine-containing nonconjugated polyelectrolyte, which provides ideal metal-nucleation sites with a surface-density on the atomic scale, in combination with the successive deposition of a facile anti-reflective coating using a conducting polymer. The hybrid electrodes are fully functional as universal electrodes for high-end flexible electronic applications, such as polymer solar cells that exhibit a high power conversion efficiency of 10% and polymer light-emitting diodes that can outperform those based on transparent conducting oxides. PMID:25790133

  16. Investigation into the Relaxation Dynamics of Polymer-Protein Conjugates Reveals Surprising Role of Polymer Solvation on Inherent Protein Flexibility.

    Science.gov (United States)

    Russo, Daniela; Plazanet, Marie; Teixeira, José; Moulin, Martine; Härtlein, Michael; Wurm, Frederik R; Steinbach, Tobias

    2016-01-11

    Fully biodegradable protein-polymer conjugates, namely, MBP-PMeEP (maltose binding protein-poly methyl-ethylene phosphonate), have been investigated in order to understand the role of polymer solvation on protein flexibility. Using elastic and quasi-elastic incoherent neutron scattering, in combination with partially deuterated conjugate systems, we are able to disentangle the polymer dynamics from the protein dynamics and meaningfully address the coupling between both components. We highlight that, in the dry state, the protein-polymer conjugates lack any dynamical transition in accordance with the generally observed behavior for dry proteins. In addition, we observe a larger flexibility of the conjugated protein, compared to the native protein, as well as a lack of polymer-glass transition. Only upon water hydration does the conjugate recover its dynamical transition, leading to the conclusion that exclusive polymer solvation is insufficient to unfreeze fluctuations on the picosecond-nanosecond time scale in biomolecules. Our results also confirm the established coupling between polymer and protein dynamics in the conjugate.

  17. Development of Bionic Polymers

    Institute of Scientific and Technical Information of China (English)

    Xu Jian; Xie Qiongdan; Guo Xinlin; Feng Lin; Jiang Lei; Tang Wenghong; Luo Xiandong; Zhang Xiaoli; Han Charles C.

    2004-01-01

    Bionics, an artificial imitation of natural products, has always been a forever dream in the fairy tale or scientific fiction when we were childhood and children live now. However, the development of science in molecular scale makes this dream of childhood and manhood realize today.Bionics, a branch of science concerned with application the data about the functioning of biological system to the solution of engineering problems, become top-priority of science in the 21st century.However, few examples are given in molecular-level or nano-scale controlling lotus-like surface (a bionic surface for vast potential application). In the same time, such a typical bionic surface (as well known, so called "Lotus-effect") is a symbol or a totem that scientists can develop a novel approach to prepare desired surface and to control its microstructure or morphology at one's pleasure.In general, a film with a water contact angle (CA) higher than 150° can be defined as a superhydrophobic surface. The Langmuir-Blodgett film prepared by using CF3(CF2)10COOH possesses the lowest surface tension, which is 6 mJ/m2 (1). However, the water CA on a smooth surface with regularly aligned C20F42 with close-hexagonal packed -CF3 groups is only 119° (2).Obviously, only adjusting chemical composition is not enough to produce a superhydrophobic surface. Wenzel et al (3) suggested that the contact angle θ' of a liquid droplet on a rough solid surface should be written as:cosθ, =γcosθ = γ(γs-γsl)/γl, here γ is a roughness factor and γsl, γs and γl denote the interfacial tensions of the solid-liquid, the solid-gas, and the liquid-gas interfaces,respectively. This γ is always larger than 1 and a rough surface will be more water-repellent or more wettable to a liquid when intrinsic contact angle θ is bigger or smaller than 90°, respectively.Therefore, a general approach to obtain superhydrophobic surfaces is using a combination of depressing surface energy and enhancing surface

  18. Polymer recycling: potential application of radiation technology

    Energy Technology Data Exchange (ETDEWEB)

    Burillo, Guillermina; Clough, Roger L. E-mail: rlcloug@sandia.gov; Czvikovszky, Tibor; Guven, Olgun; Le Moel, Alain; Liu Weiwei; Singh, Ajit; Yang Jingtian; Zaharescu, Traian

    2002-04-01

    Management of solid waste is an important problem, which is becoming progressively worse as a byproduct of continuing economic growth and development. Polymeric materials (plastics and rubbers) comprise a steadily increasing proportion of the municipal and industrial waste going into landfill. Development of technologies for reducing polymeric waste, which are acceptable from the environmental standpoint, and which are cost-effective, has proven to be a difficult challenge due to complexities inherent in the reuse of polymers. Establishing optimal processes for the reuse/recycling of polymeric materials thus remains a worldwide challenge as we enter the new century. Due to the ability of ionizing radiation to alter the structure and properties of bulk polymeric materials, and the fact that it is applicable to essentially all polymer types, irradiation holds promise for impacting the polymer waste problem. The three main possibilities for use of radiation in this application are: (1) enhancing the mechanical properties and performance of recovered materials or material blends, principally through crosslinking, or through surface modification of different phases being combined; (2) treatment causing or enhancing the decomposition of polymers, particularly through chain scission, leading to recovery of either low molecular weight mixtures, or powders, for use as chemical feedstocks or additives; (3) production of advanced polymeric materials designed for environmental compatibility. This paper provides an overview of the polymer recycling problem, describes the major technological obstacles to the implementation of recycling technologies, and outlines some of the approaches being taken. A review of radiation-based recycling research is then provided, followed by a discussion of future directions where irradiation may be relevant to the problems currently inhibiting the widespread recycling of polymeric materials.

  19. Ion-Conducting Organic/Inorganic Polymers

    Science.gov (United States)

    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.

  20. An overview of the pharmacokinetics of polymer-based nanoassemblies and nanoparticles.

    Science.gov (United States)

    Zhao, Qing-He; Qiu, Li-Yan

    2013-10-01

    Advancements in the design and synthesis of polymer-based nanoassemblies and nanoparticles, combined with achievements in nanotechnology and medicine, have resulted in remarkable applications of polymer nanosystems in the areas of nanomedicine and pharmaceutical sciences. However, a complete understanding of the absorption, distribution, metabolism, and elimination (ADME) processes of such polymer nanosystems in living systems has not been achieved. The influences of the pharmacokinetic parameters of polymer nanomaterials on the ADME processes are reviewed in this article, with discussions of the absorption and transportation of polymer nanoparticles across biological barriers, the factors affecting the bodily distribution of polymer nanocarriers, the transformation of polymer nanomaterials in vivo, the elimination pathway of polymer nanoparticles from biological systems, and perspectives of future pharmacokinetics and safety investigations of polymer-based nanoassemblies. A full and better understanding of the pharmacokinetic parameters of polymer-based nanomaterials is of vital importance in developing polymer nanosystems with optimal pharmacokinetics and biological safety for applications in nanomedicine and the pharmaceutical industry. PMID:24016113

  1. New method for preparing a liquid crystal polymer that exhibits linearly polarized white fluorescence

    Science.gov (United States)

    Zheng, Shi-jun; Kun, Wang; Kobayashi, Takaomi

    2011-03-01

    With the aim of developing a single-chain white-light-emitting polymer, liquid crystal (LC) polymers with a shish-kebab-type moiety on their cross-conjugated (p-phenylene)s-poly(p-phenylenevinylene)s main chain were synthesized by Gilch polymerization. They were characterized by nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and polarizing optical microscopy (POM). 1H-NMR indicated that the polymers had a shish-kebab structure, which strongly suppressed the formation of structural defects in the polymers. DSC revealed that the polymers had thermotropic LC properties, indicating that the LC polymers were enantiotropic. XRD showed that the polymers had a mesophase, which implies that they were in a smectic LC phase. A polymer with "kebabs" of 2,5-bis(4'-alkoxyphenyl)benzene was combined with an aligned polyimide film with orientated microgrooves. The polymer main chain was aligned due to the orientation of the "kebabs" of the uniform cross-conjugated structure. It lay between the kebabs and the "shish" of the polymer main chains. The aligned polymer main chain emitted yellow light while and the oriented LC side chains emitted blue light emission. These two emissions resulted in linearly polarized white fluorescence.

  2. Polymerization of cyanoacetylene under pressure: Formation of carbon nitride polymers and bulk structures

    Science.gov (United States)

    Khazaei, Mohammad; Liang, Yunye; Venkataramanan, Natarajan S.; Kawazoe, Yoshiyuki

    2012-02-01

    High-pressure phase transitions of polar and nonpolar molecular structures of cyanoacetylene (HC3N) are studied by using first-principles simulations at constant pressure. In both polar and nonpolar crystals, at pressure ˜20 GPa, the cyanoacetylene molecules are interconnected together and form polyacrylonitrile (PA) polymers. At pressure ˜30 GPa, PA polymers are transformed to polymers with fused pyridine rings (FPR's). The individual geometrical structures of PA and FPR polymers obtained from polar and nonpolar molecular crystals of cyanoacetylene are identical, but their stacking is different. At pressures above 40 GPa, the FPR polymers are interconnected together and new three-dimensional (3D) carbon nitride systems are formed. At ambient pressure, the long-length PA and FPR polymers are metallic, and the created 3D structures are an insulator with energy band gaps around 2.85 eV. The electron transport characteristics of FPR polymers with different lengths are investigated at finite biases by using the nonequilibrium Green's function technique combined with density functional theory (DFT) by connecting the polymers to gold electrodes. The results show that FPR polymers have negative differential resistance behavior. Our time-dependent DFT calculations reveal that FPR polymers can absorb light in the visible region. From our results, it is expected that the FPR polymers will be a good material for optoelectronic applications.

  3. Polymer:fullerene bulk heterojunction solar cells

    Directory of Open Access Journals (Sweden)

    Jenny Nelson

    2011-10-01

    Full Text Available The efficiency of solar cells made from a conjugated polymer blended with a fullerene derivative has risen from around 1 % to over 9 % in the last ten years, making organic photovoltaic technology a viable contender for commercialization. The efficiency increases have resulted from the development of new materials with lower optical gaps, new polymer:fullerene combinations with higher charge separated state energies, and new approaches to control the blend microstructure, all driven by a qualitative understanding of the principles governing organic solar cell operation. In parallel, a device physics framework has been developed that enables the rational design of device structures and materials for improved organic photovoltaic devices. We review developments in both materials science and device physics for organic photovoltaics.

  4. Metal-polymer nanocomposites for functional applications

    Energy Technology Data Exchange (ETDEWEB)

    Faupel, Franz; Zaporojtchenko, Vladimir; Strunskus, Thomas [Christian-Albrechts-Universitaet zu Kiel (Germany). Institut fuer Materialwissenschaft - Materialverbunde; Elbahri, Mady [Christian-Albrechts-Universitaet zu Kiel (Germany). Institut fuer Materialwissenschaft - Nanochemistry and Engineering

    2010-12-15

    Nanocomposites combine favorable features of the constituents on the nanoscale to obtain new functionalities. The present paper is concerned with the preparation of polymer-based nanocomposites consisting of metal nanoparticles in a polymer matrix and the resulting functional properties. Emphasis is placed on vapor phase deposition which inter alia allows the incorporation of alloy clusters with well defined composition and tailored filling factor profiles. Examples discussed here include optical composites with tuned particle surface plasmon resonances for plasmonic applications, magnetic high frequency materials with cut-off frequencies well above 1 GHz, sensors that are based on the dramatic change in the electronic properties near the percolation threshold, and antibacterial coatings which benefit from the large effective surface of nanoparticles and the increased chemical potential which both strongly enhance ion release. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Nanostructured assemblies from amphiphilic ABC multiblock polymers

    Science.gov (United States)

    Hillmyer, Marc A.

    2012-02-01

    Amphiphilic AB diblock copolymers containing a water compatible segment can self-assemble in aqueous media to give supramolecular structures that include simple spherical micelles and macromolecular vesicles termed polymersomes. Amphiphilic ABA triblocks with hydrophobic end blocks can adopt analogous structures but can also form gels at high polymer concentrations. The structural and chemical diversity demonstrated in block copolymer micelles and gels makes them attractive for applications ranging from drug delivery to personal care products to nanoreactors. The inclusion of a third block in amphiphilic ABC triblock systems can lead to a much wider array of self-assembled structures that depend not only on composition but also on block sequence, architecture and incompatibility considerations. I will present our recent efforts on tuning micelle and gel structure and behavior using controlled architecture ABC triblocks. The combination of diverse polymer segments into a single macromolecule is a powerful method for development of self-assembled structures with both new form and new function.

  6. High temperature chemically resistant polymer concrete

    Science.gov (United States)

    Sugama, T.; Kukacka, L.E.

    High temperature chemically resistant, non-aqueous polymer concrete composites consist of about 12 to 20% by weight of a water-insoluble polymer binder. The binder is polymerized in situ from a liquid vinyl-type monomer or mixture of vinyl containing monomers such as triallylcyanurate, styrene, acrylonitrile, acrylamide, methacrylamide, methyl-methacrylate, trimethylolpropane trimethacrylate and divinyl benzene. About 5 to 40% by weight of a reactive inorganic filler selected from the group consisting of tricalcium silicate and dicalcium silicate and mixtures containing less than 2% free lime, and about 48 to 83% by weight of silica sand/ and a free radical initiator such as di-tert-butyl peroxide, azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide, other orgaic peroxides and combinations to initiate polymerization of the monomer in the presence of the inorganic filers are used.

  7. Understanding Molecular Interactions within Chemically Selective Layered Polymer Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Gary J. Blanchard

    2009-06-30

    This work focuses on two broad issues. These are (1) the molecular origin of the chemical selectivity achieved with ultrathin polymer multilayers, and (2) how the viscoelastic properties of the polymer layers are affected by exposure to solvent and analytes. These issues are inter-related, and to understand them we need to design experiments that probe both the energetic and kinetic aspects of interfacial adsorption processes. This project focuses on controling the chemical structure, thickness, morphology and sequential ordering of polymer layers bound to interfaces using maleimide-vinyl ether and closely related alternating copolymerization chemistry and efficient covalent cross-linking reactions that allow for layer-by-layer polymer deposition. This chemistry has been developed during the funding cycle of this Grant. We have measure the equilibrium constants for interactions between specific layers within the polymer interfaces and size-controlled, surface-functionalized gold nanoparticles. The ability to control both size and functionality of gold nanoparticle model analytes allows us to evaluate the average “pore size” that characterizes our polymer films. We have measured the “bulk” viscosity and shear modulus of the ultrathin polymer films as a function of solvent overlayer identity using quartz crystal microbalance complex impedance measurements. We have measured microscopic viscosity at specific locations within the layered polymer interfaces with time-resolved fluorescence lifetime and depolarization techniques. We combine polymer, cross-linking and nanoparticle synthetic expertise with a host of characterization techniques, including QCM gravimetry and complex impedance analysis, steady state and time-resolved spectroscopies.

  8. Dielectric Actuation of Polymers

    Science.gov (United States)

    Niu, Xiaofan

    Dielectric polymers are widely used in a plurality of applications, such as electrical insulation, dielectric capacitors, and electromechanical actuators. Dielectric polymers with large strain deformations under an electric field are named dielectric elastomers (DE), because of their relative low modulus, high elongation at break, and outstanding resilience. Dielectric elastomer actuators (DEA) are superior to traditional transducers as a muscle-like technology: large strains, high energy densities, high coupling efficiency, quiet operation, and light weight. One focus of this dissertation is on the design of DE materials with high performance and easy processing. UV radiation curing of reactive species is studied as a generic synthesis methodology to provide a platform for material scientists to customize their own DE materials. Oligomers/monomers, crosslinkers, and other additives are mixed and cured at appropriate ratios to control the stress-strain response, suppress electromechanical instability of the resulting polymers, and provide stable actuation strains larger than 100% and energy densities higher than 1 J/g. The processing is largely simplified in the new material system by removal of the prestretching step. Multilayer stack actuators with 11% linear strain are demonstrated in a procedure fully compatible with industrial production. A multifunctional DE derivative material, bistable electroactive polymer (BSEP), is invented enabling repeatable rigid-to-rigid deformation without bulky external structures. Bistable actuation allows the polymer actuator to have two distinct states that can support external load without device failure. Plasticizers are used to lower the glass transition temperature to 45 °C. Interpenetrating polymer network structure is established inside the BSEP to suppress electromechanical instability, providing a breakdown field of 194 MV/m and a stable bistable strain as large as 228% with a 97% strain fixity. The application of BSEP

  9. Oxygen reduction on carbon supported platinum catalysts in high temperature polymer electrolytes

    DEFF Research Database (Denmark)

    Qingfeng, Li; Hjuler, Hans Aage; Bjerrum, Niels

    2000-01-01

    Oxygen reduction on carbon supported platinum catalysts has been investigated in H3PO4, H3PO4-doped Nafion and polybenzimidazole (PBI) polymer electrolytes in a temperature range up to 190 degrees C. Compared with pure H3PO4, the combination of H3PO4 and polymer electrolytes can significantly imp...

  10. Dynamics of polymers

    Energy Technology Data Exchange (ETDEWEB)

    Buchenau, U. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Energieverfahrenstechnik

    1996-11-01

    Neutron scattering from amorphous polymers allows to switch from incoherent to coherent scattering in the same substance. The power of the tool for the study of the picosecond dynamics of disordered matter is illustrated for polybutadiene, polycarbonate and polystyrene. The results suggest a mixture of sound waves and localized modes, strongly interacting with each other, in the picosecond range. (author) 8 figs., tabs., 39 refs.

  11. Dynamics of polymers

    International Nuclear Information System (INIS)

    Neutron scattering from amorphous polymers allows to switch from incoherent to coherent scattering in the same substance. The power of the tool for the study of the picosecond dynamics of disordered matter is illustrated for polybutadiene, polycarbonate and polystyrene. The results suggest a mixture of sound waves and localized modes, strongly interacting with each other, in the picosecond range. (author) 8 figs., tabs., 39 refs

  12. High performance polymer concrete

    OpenAIRE

    Frías, M.; San-José, J. T.

    2007-01-01

    This paper studies the performance of concrete whose chief components are natural aggregate and an organic binder —a thermosetting polyester resin— denominated polymer concrete or PC. The material was examined macro- and microscopically and its basic physical and mechanical properties were determined using mercury porosimetry, scanning electron microscopy (SEM-EDAX), X-ray diffraction (XRD) and strength tests (modulus of elasticity, stress-strain curves and ultimate strengths). A...

  13. Knots in polymers

    Indian Academy of Sciences (India)

    Yacov Kantov

    2005-06-01

    Knots and topological entanglements play an important role in the statistical mechanics of polymers. While topological entanglement is a global property, it is possible to study the size of a knotted region both numerically and analytically. It can be shown that long-range repulsive interactions, as well as entropy favor small knots in dilute systems. However, in dense systems and at the -point in two dimensions the uncontracted knot configuration is the most likely.

  14. CLASSIFICATION OF BIODEGRADABLE POLYMERS

    Directory of Open Access Journals (Sweden)

    I. I. Karpunin

    2015-01-01

    Full Text Available The executed investigations have made it possible to ascertain that a morphological structure of starch granules mainly determine technological peculiarities of starch isolation from raw material, its modification and its later use. Morphological structure of starch granules primarily depends on type of plant starch-containing raw material which has been used for its isolation. Class of raw material exerts a strong impact on the shape and size of the granules. Linear “light” amylose chains and “heavy” amylopectin branch chains form a starch granule ultrastructure. X-ray research has proved that starch granules are characterized by presence of interlacing amorphous and crystalline regions. In this case polymer orientation using stretching of the obtained end product influences on its physical and mechanical  indices which are increasing due to polymer orientation. For the purpose of packaging orientation of polymer films can solve such important problems as significant improvement of operational properties, creation of  thermosetting film materials, improvement of qualitative indices of the recycled film.Results of the conducted research have proved the fact that it is necessary to make changes in technology in order to increase biological degradability of the recycled packaging made from polymers and improve physical and mechanical indices. In this regard film production technology presupposes usage of such substances as stark and others which are characterized by rather large presence of branch chains of molecules and interlacing amorphous and crystalline regions. Such approach makes it possible to obtain after-use package which is strong and quickly degradable by micro-organisms.

  15. Conjugated polymer nanoparticles

    Science.gov (United States)

    Tuncel, Dönüs; Demir, Hilmi Volkan

    2010-04-01

    Conjugated polymer nanoparticles are highly versatile nano-structured materials that can potentially find applications in various areas such as optoelectronics, photonics, bio-imaging, bio-sensing and nanomedicine. Their straightforward synthesis in desired sizes and properties, biocompatibility and non-toxicity make these materials highly attractive for the aforementioned applications. This feature article reviews the recent developments in the synthesis, characterization, properties and application of these exciting nanostructured materials.

  16. Electrochemical polymer electrolyte membranes

    CERN Document Server

    Fang, Jianhua; Wilkinson, David P

    2015-01-01

    Electrochemical Polymer Electrolyte Membranes covers PEMs from fundamentals to applications, describing their structure, properties, characterization, synthesis, and use in electrochemical energy storage and solar energy conversion technologies. Featuring chapters authored by leading experts from academia and industry, this authoritative text: Discusses cutting-edge methodologies in PEM material selection and fabricationPoints out important challenges in developing PEMs and recommends mitigation strategies to improve PEM performanceAnalyzes the cur

  17. Polymers in Fractal Disorder

    OpenAIRE

    Fricke, Niklas

    2016-01-01

    This work presents a numerical investigation of self-avoiding walks (SAWs) on percolation clusters, a canonical model for polymers in disordered media. A new algorithm has been developed allowing exact enumeration of over ten thousand steps. This is an increase of several orders of magnitude compared to previously existing enumeration methods, which allow for barely more than forty steps. Such an increase is achieved by exploiting the fractal structure of critical percolation clusters: they a...

  18. Mass transport in polymers

    OpenAIRE

    Ferrari, Maria Chiara

    2009-01-01

    The study of mass transport in polymeric membranes has grown in importance due to its potential application in many processes such as separation of gases and vapors, packaging, controlled drug release. The diffusion of a low molecular weight species in a polymer is often accompanied by other phenomena like swelling, reactions, stresses, that have not been investigated in all their aspects yet. Furthermore, novel materials have been developed that include inorganic fillers, reactive functional...

  19. Conductive Polymer Composites

    OpenAIRE

    Pierini, Filippo

    2013-01-01

    In recent years, nanotechnologies have led to the production of materials with new and sometimes unexpected qualities through the manipulation of nanoscale components. This research aimed primarily to the study of the correlation between hierarchical structures of hybrid organic-inorganic materials such as conductive polymer composites (CPCs). Using a bottom-up methodology, we could synthesize a wide range of inorganic nanometric materials with a high degree of homogeneity and purity, ...

  20. Absorbable and biodegradable polymers

    CERN Document Server

    Shalaby, Shalaby W

    2003-01-01

    INTRODUCTION NOTES: Absorbable/Biodegradable Polymers: Technology Evolution. DEVELOPMENT AND APPLICATIONOF NEW SYSTEMS: Segmented Copolyesters with Prolonged Strength Retention Profiles. Polyaxial Crystalline Fiber-Forming Copolyester. Polyethylene Glycol-Based Copolyesters. Cyanoacrylate-Based Systems as Tissue Adhesives. Chitosan-Based Systems. Hyaluronic Acid-Based Systems. DEVELOPMENTS IN PREPARATIVE, PROCESSING, AND EVALUATION METHODS: New Approaches to the Synthesis of Crystalline. Fiber-Forming Aliphatic Copolyesters. Advances in Morphological Development to Tailor the Performance of Me

  1. Tuning the entropic spring to dictate order and functionality in polymer conjugated peptide biomaterials

    Science.gov (United States)

    Keten, Sinan

    Hybrid peptide-polymer conjugates have the potential to combine the advantages of natural proteins and synthetic polymers, resulting in biomaterials with improved stability, controlled assembly, and tailored functionalities. However, the effect of polymer conjugation on peptide structural organization and functionality, along with the behavior of polymers at the interface with biomolecules remain to be fully understood. This talk will summarize our recent efforts towards establishing a modeling framework to design entropic forces in helix-polymer conjugates and polymer-conjugated peptide nanotubes to achieve hierarchical self-assembling systems with predictable order. The first part of the talk will discuss how self-assembly principles found in biology, combined with polymer physics concepts can be used to create artificial membranes that mimic certain features of ion channels. Thermodynamics and kinetics aspects of self-assembly and how it governs the growth and stacking sequences of peptide nanotubes will be discussed, along with its implications for nanoscale transport. The second part of the talk will review advances related to modeling polymer conjugated coiled coils at relevant length and time scales. Atomistic simulations combined with sampling techniques will be presented to discuss the energy landscapes governing coiled-coil stability, revealing cascades of events governing disassembly. This will be followed by a discussion of mechanisms through which polymers can stabilize small proteins, such as shielding of solvents, and how specific peptide sequences can reciprocate by altering polymer conformations. Correlations between mechanical and thermal stability of peptides will be discussed. Finally, coarse-grained simulations will provide insight into how the location of polymer attachment changes entropic forces and higher-level organization in helix bundle assemblies. Our findings set the stage for a materials-by-design capability towards dictating complex

  2. Lattice polymer automata

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, S. [Los Alamos National Lab., NM (United States)]|[Santa Fe Institute, NM (United States); Smith, J.R. [Santa Fe Institute, NM (United States)]|[Massachusetts Media Lab., Cambridge, MA (United States). Physics and Media Group

    1995-05-01

    We present a new style of molecular dynamics and self-assembly simulation, the Lattice Polymer Automaton (LPA). In the LPA all interactions, including electromagnetic forces, are decomposed and communicated via propagating particles, {open_quotes}photons.{close_quotes} The monomer-monomer bondforces, the molecular excluded volume forces, the longer range intermolecular forces, and the polymer-solvent interactions may all be modeled with propagating particles. The LPA approach differs significantly from both of the standard approaches, Monte Carlo lattice methods and Molecular Dynamics simulations. On the one hand, the LPA provides more realism than Monte Carlo methods, because it produces a time series of configurations of a single molecule, rather than a set of causally unrelated samples from a distribution of configurations. The LPA can therefore be used directly to study dynamical properties; one can in fact watch polymers move in real time. On the other hand, the LPA is fully discrete, and therefore much simpler than traditional Molecular Dynamics models, which are continuous and operate on much shorter time scales. Due to this simplicity it is possible to simulate longer real time periods, which should enable the study of molecular self-organization on workstations supercomputers are not needed.

  3. Hyperbranched Polymer-Based Electrolyte for Lithium Polymer Batteries

    Institute of Scientific and Technical Information of China (English)

    Takahito Itoh

    2005-01-01

    @@ 1Introduction Solid polymer electrolytes have attracted much attention as electrolyte materials for all solid-state recharge able lithium batteries, and poly ( ethylene oxide) ( PEO)-based polymer electrolytes are among the most intensively studied systems[1-3]. Hyperbranched polymers have unique properties such as completely amorphous, highly soluble in common organic solvent and processible because of the highly branched nature[4,5].

  4. Polymer crowding and shape distributions in polymer-nanoparticle mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Wei Kang; Denton, Alan R., E-mail: alan.denton@ndsu.edu [Department of Physics, North Dakota State University, Fargo, North Dakota 58108-6050 (United States)

    2014-09-21

    Macromolecular crowding can influence polymer shapes, which is important for understanding the thermodynamic stability of polymer solutions and the structure and function of biopolymers (proteins, RNA, DNA) under confinement. We explore the influence of nanoparticle crowding on polymer shapes via Monte Carlo simulations and free-volume theory of a coarse-grained model of polymer-nanoparticle mixtures. Exploiting the geometry of random walks, we model polymer coils as effective penetrable ellipsoids, whose shapes fluctuate according to the probability distributions of the eigenvalues of the gyration tensor. Accounting for the entropic cost of a nanoparticle penetrating a larger polymer coil, we compute the crowding-induced shift in the shape distributions, radius of gyration, and asphericity of ideal polymers in a theta solvent. With increased nanoparticle crowding, we find that polymers become more compact (smaller, more spherical), in agreement with predictions of free-volume theory. Our approach can be easily extended to nonideal polymers in good solvents and used to model conformations of biopolymers in crowded environments.

  5. Polymer-filled microcontainers for oral delivery loaded using supercritical impregnation

    DEFF Research Database (Denmark)

    Marizza, Paolo; Keller, Stephan Sylvest; Müllertz, Anette;

    2014-01-01

    with a quasi-no-waste performance. Then ketoprofen is impregnated in the polymer matrix by using supercritical carbon dioxide (scCO2) as loading medium. The amount of polymer is controlled by the volume and the number of droplets of dispensed polymer and drug loading is tuned by varying the impregnation...... parameters. Compared to solid dispersions of the same drug and polymer, scCO2-impregnated microcontainers exhibit a more reproducible drug loading and a faster dissolution rate of the active compound which allows drug release to be modulated. The combination of these loading techniques potentially allows...

  6. Processing polymers with cyclodextrins

    Science.gov (United States)

    Williamson, Brandon Robert

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

  7. Simulation of magnetic active polymers for versatile microfluidic devices

    CERN Document Server

    Gusenbauer, Markus; Fischbacher, Johann; Reichel, Franz; Exl, Lukas; Bance, Simon; Kataeva, Nadezhda; Binder, Claudia; Brückl, Hubert; Schrefl, Thomas

    2013-01-01

    We propose to use a compound of magnetic nanoparticles (20-100 nm) embedded in a flexible polymer (Polydimethylsiloxane PDMS) to filter circulating tumor cells (CTCs). The analysis of CTCs is an emerging tool for cancer biology research and clinical cancer management including the detection, diagnosis and monitoring of cancer. The combination of experiments and simulations lead to a versatile microfluidic lab-on-chip device. Simulations are essential to understand the influence of the embedded nanoparticles in the elastic PDMS when applying a magnetic gradient field. It combines finite element calculations of the polymer, magnetic simulations of the embedded nanoparticles and the fluid dynamic calculations of blood plasma and blood cells. With the use of magnetic active polymers a wide range of tunable microfluidic structures can be created. The method can help to increase the yield of needed isolated CTCs.

  8. Claisen thermally rearranged (CTR) polymers

    Science.gov (United States)

    Tena, Alberto; Rangou, Sofia; Shishatskiy, Sergey; Filiz, Volkan; Abetz, Volker

    2016-01-01

    Thermally rearranged (TR) polymers, which are considered the next-generation of membrane materials because of their excellent transport properties and high thermal and chemical stability, are proven to have significant drawbacks because of the high temperature required for the rearrangement and low degree of conversion during this process. We demonstrate that using a [3,3]-sigmatropic rearrangement, the temperature required for the rearrangement of a solid glassy polymer was reduced by 200°C. Conversions of functionalized polyimide to polybenzoxazole of more than 97% were achieved. These highly mechanically stable polymers were almost five times more permeable and had more than two times higher degrees of conversion than the reference polymer treated under the same conditions. Properties of these second-generation TR polymers provide the possibility of preparing efficient polymer membranes in a form of, for example, thin-film composite membranes for various gas and liquid membrane separation applications.

  9. Terminology of Polymers Containing Ionizable or Ionic Groups and of Polymers Containing Ions, VII.3

    Directory of Open Access Journals (Sweden)

    Jarm, V.

    2009-10-01

    Full Text Available The class of ionic polymers has widespread application in many areas of everyday life, in industrial production, and in the processes of living matter. The properties of ionic polymers depend on the polymer structure, and the nature, content, and location of the ionic groups. To clear differences among various ionic polymers, the IUPAC recommendations present 34 definitionsfor the ionomer, polyacid, polybase, polyampholytic polymer, ion-exchange polymer, polybetaine, polyelectrolyte, intrinsically conducting polymer, solid polymer electrolyte, etc

  10. Method for bonding a thermoplastic polymer to a thermosetting polymer component

    OpenAIRE

    Van Tooren, M.J.L.

    2012-01-01

    The invention relates to a method for bonding a thermoplastic polymer to a thermosetting polymer component, the thermoplastic polymer having a melting temperature that exceeds the curing temperature of the thermosetting polymer. The method comprises the steps of providing a cured thermosetting polymer component comprising an implant of a thermoplastic polymer at least at the part of the thermosetting polymer component to be bonded, locating a thermoplastic polymer in contact with at least the...

  11. Side-chain functionalized poly(3-hexylthiophene)-based copolymers: synsthesis and characterization of derivatives for application in polymer solar cells

    OpenAIRE

    CAMPO, Bert

    2009-01-01

    Conjugated polymers combine semi-conductive electrical properties with desirable mechanical properties such as light weight and high mechanical strength and flexibility. This enables the development of new technologies and applications based on these materials. Poly(3-hexylthiophene) is a conjugated polymer that has been extensively investigated in polymer:fullerene bulk heterojunction solar cells. ...

  12. Investigations of functional electroactive polymers

    OpenAIRE

    Tiitu, Mari

    2006-01-01

    Conjugated polymers containing pi-conjugated backbones form a scientifically and technologically important class of polymers. In their undoped form they are semiconductors, but they can be doped for electrical conductivity, and allow redox-activity, which all can lead to functional materials. One of the most important conjugated polymers in large scale applications is polyaniline due to its economics and good stability. Polyaniline is used for applications requiring conductivity as well as co...

  13. Friction between Ring Polymer Brushes

    OpenAIRE

    2015-01-01

    Friction between ring-polymer brushes at melt densities sliding past each other are studied using extensive course-grained molecular dynamics simulations and scaling arguments, and the results are compared to the friction between linear-polymer brushes. We show that for a velocity range spanning over three decades, the frictional forces measured for ring-polymer brushes are half the corresponding friction in case of linear brushes. In the linear-force regime, the weak inter-digitation of two ...

  14. Wear of polymers and composites

    CERN Document Server

    Abdelbary, Ahmed

    2015-01-01

    In the field of tribology, the wear behaviour of polymers and composite materials is considered a highly non-linear phenomenon. Wear of Polymers and Composites introduces fundamentals of polymers and composites tribology. The book suggests a new approach to explore the effect of applied load and surface defects on the fatigue wear behaviour of polymers, using a new tribometer and thorough experiments. It discusses effects of surface cracks, under different static and cyclic loading parameters on wear, and presents an intelligent algorithm, in the form of a neural network, to map the relations

  15. Progress in polymer solar cell

    Institute of Scientific and Technical Information of China (English)

    LI LiGui; LU GuangHao; YANG XiaoNiu; ZHOU EnLe

    2007-01-01

    This review outlines current progresses in polymer solar cell. Compared to traditional silicon-based photovoltaic (PV) technology, the completely different principle of optoelectric response in the polymer cell results in a novel configuration of the device and more complicated photovoltaic generation process. The conception of bulk-heterojunction (BHJ) is introduced and its advantage in terms of morphology is addressed. The main aspects including the morphology of photoactive layer, which limit the efficiency and stability of polymer solar cell, are discussed in detail. The solutions to boosting up both the efficiency and stability (lifetime) of the polymer solar cell are highlighted at the end of this review.

  16. Polymer-based solar cells

    Directory of Open Access Journals (Sweden)

    Alex C. Mayer

    2007-11-01

    Full Text Available A significant fraction of the cost of solar panels comes from the photoactive materials and sophisticated, energy-intensive processing technologies. Recently, it has been shown that the inorganic components can be replaced by semiconducting polymers capable of achieving reasonably high power conversion efficiencies. These polymers are inexpensive to synthesize and can be solution-processed in a roll-to-roll fashion with high throughput. Inherently poor polymer properties, such as low exciton diffusion lengths and low mobilities, can be overcome by nanoscale morphology. We discuss polymer-based solar cells, paying particular attention to device design and potential improvements.

  17. Small angle scattering and polymers

    Energy Technology Data Exchange (ETDEWEB)

    Cotton, J.P. [Laboratoire Leon Brillouin (LLB) - Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)

    1996-12-31

    The determination of polymer structure is a problem of interest for both statistical physics and industrial applications. The average polymer structure is defined. Then, it is shown why small angle scattering, associated with isotopic substitution, is very well suited to the measurement of the chain conformation. The corresponding example is the old, but pedagogic, measurement of the chain form factor in the polymer melt. The powerful contrast variation method is illustrated by a recent determination of the concentration profile of a polymer interface. (author) 12 figs., 48 refs.

  18. Colorometric detection of water using MOF-polymer films and composites

    Science.gov (United States)

    Allendorf, Mark D.; Talin, Albert Alec

    2016-05-24

    A method including exposing a mixture of a porous metal organic framework (MOF) and a polymer to a predetermined molecular species, wherein the MOF has an open metal site for the predetermined molecular species and the polymer has a porosity for the predetermined molecular species; and detecting a color change of the MOF in the presence of the predetermined molecular species. A method including combining a porous metal organic framework (MOF) and a polymer, wherein the MOF has an open metal site for a predetermined molecular species and the polymer has a porosity for the predetermined molecular species. An article of manufacture including a mixture of a porous metal organic framework (MOF) and a polymer, wherein the MOF has an open metal site for a predetermined molecular species and the polymer has a porosity for the predetermined molecular species.

  19. Hybrid Polymer-Network Hydrogels with Tunable Mechanical Response

    Directory of Open Access Journals (Sweden)

    Sebastian Czarnecki

    2016-03-01

    Full Text Available Hybrid polymer-network gels built by both physical and covalent polymer crosslinking combine the advantages of both these crosslinking types: they exhibit high mechanical strength along with excellent fracture toughness and extensibility. If these materials are extensively deformed, their physical crosslinks can break such that strain energy is dissipated and irreversible fracturing is restricted to high strain only. This mechanism of energy dissipation is determined by the kinetics and thermodynamics of the physical crosslinking contribution. In this paper, we present a poly(ethylene glycol (PEG based material toolkit to control these contributions in a rational and custom fashion. We form well-defined covalent polymer-network gels with regularly distributed additional supramolecular mechanical fuse links, whose strength of connectivity can be tuned without affecting the primary polymer-network composition. This is possible because the supramolecular fuse links are based on terpyridine–metal complexation, such that the mere choice of the fuse-linking metal ion adjusts their kinetics and thermodynamics of complexation–decomplexation, which directly affects the mechanical properties of the hybrid gels. We use oscillatory shear rheology to demonstrate this rational control and enhancement of the mechanical properties of the hybrid gels. In addition, static light scattering reveals their highly regular and well-defined polymer-network structures. As a result of both, the present approach provides an easy and reliable concept for preparing hybrid polymer-network gels with rationally designed properties.

  20. Drug Delivery Vehicles Based on Albumin-Polymer Conjugates.

    Science.gov (United States)

    Jiang, Yanyan; Stenzel, Martina

    2016-06-01

    Albumin has been a popular building block to create nanoparticles for drug delivery purposes. The performance of albumin as a drug carrier can be enhanced by combining protein with polymers, which allows the design of carriers to encompass a broader spectrum of drugs while features unique to synthetic polymers such as stimuli-responsiveness are introduced. Nanoparticles based on polymer-albumin hybrids can be divided into two classes: one that carries album as a bioactive surface coating and the other that uses albumin as biocompatible, although nonbioactive, building block. Nanoparticles with bioactive albumin surface coating can either be prepared by self-assembly of albumin-polymer conjugates or by postcoating of existing nanoparticles with albumin. Albumin has also been used as building block, either in its native or denatured form. Existing albumin nanoparticles are coated with polymers, which can influence the degradation of albumin or impact on the drug release. Finally, an alternative way of using albumin by denaturing the protein to generate a highly functional chain, which can be modified with polymer, has been presented. These albumin nanoparticles are designed to be extremely versatile so that they can deliver a wide variety of drugs, including traditional hydrophobic drugs, metal-based drugs and even therapeutic proteins and siRNA. PMID:26947019

  1. Self-assembled polymer nanocomposites and their networks

    Science.gov (United States)

    Patil, Nitin Vikas

    This dissertation describes new routes to synthesize polymer nanocomposite networks via self-assembly. Polymerizable structure directing agents (referred to as surfmers) obtained by end-group functionalization preserves the structure-directing capabilities of the surfactant for templating ordered mesoporous silica particle growth, while simultaneously generating a reactive matrix for polymer network formation through reactive end groups in the presence of intimately mixed mesoporous silicates. A combination of small angle X-ray scattering, surface area, and microscopy experiments on mesoporous silica indicated the structure directing capabilities of surfmers. Free-radical polymerization of the surfmer leads to novel crosslinked nanocomposites networks. Multiple experiments, including gel permeation chromatography, swelling, and solid state NMR experiments on polymer nanocomposites gave evidence of the polymerization of surfmer leading to formation of crosslink networks. Polymer nanocomposites with varied silica content were prepared. Effects of silica content on polymer nanocomposites were studied on rheometer. Results obtained from rheological experiments indicate that the storage (G') and loss modulus (G") increases with increase in the content of mesoporous silica. In this way, the nanocomposites networks obtained via self-assembly shows independent behavior with respect to frequency in rheological experiments. Additionally, this self-assembled route was extended to synthesize biodegradable and biocompatible polymer nanocomposites networks. The nanocomposite networks obtained with 15% of silica content showed the increase in storage modulus by two orders of magnitude in rheological experiments.

  2. Relaxor fluorinated polymers: novel applications and recent developments

    Science.gov (United States)

    Bauer, François; Dos Santos, Domingues; Zhang, Qiming

    2011-04-01

    It has been found that by introducing defects into the P(VDF-TrFE) copolymers, it is possible to convert the polymer from a normal ferroelectric to a relaxor ferroelectric. A new class of ferroelectric polymers, i.e., the terpolymers of P(VDF-TrFE-CFE) or of P(VDF-TrFE-CTFE), was developed from the normal ferroelectric PVDF-TrFE polymer by employing proper defect modifications which eliminate detrimental effects associated with a normal first order F-P transition while maintaining high material responses. Relevant studies show that this class of electroactive polymers offers unique properties in comparison with other ferroelectric polymers. The syntheses of these relaxor ferroelectric polymers have been done by a combination of the suspension polymerization process and an oxygen-activated initiator at a temperature of 40 °C. Films from cast solution can be made in different length and thicknesses. Stretching of these films increases the performance as well as the mechanical properties. These relaxor-ferroelectric terpolymers P(VDF-TrFE-CFE), P(VDF-TrFE-CTFE) are multifunctional i.e. electrostrictive material, dielectric for electric energy storage. The terpolymer exhibits high electrostrictive strain (>7%) with relatively high modulus (>0.4GPa). Examples of devices applications using unimorphe systems are presented. Micropump and Optical device concerning a liquid-filled varifocal lens on a chip are described.

  3. Drug Delivery Vehicles Based on Albumin-Polymer Conjugates.

    Science.gov (United States)

    Jiang, Yanyan; Stenzel, Martina

    2016-06-01

    Albumin has been a popular building block to create nanoparticles for drug delivery purposes. The performance of albumin as a drug carrier can be enhanced by combining protein with polymers, which allows the design of carriers to encompass a broader spectrum of drugs while features unique to synthetic polymers such as stimuli-responsiveness are introduced. Nanoparticles based on polymer-albumin hybrids can be divided into two classes: one that carries album as a bioactive surface coating and the other that uses albumin as biocompatible, although nonbioactive, building block. Nanoparticles with bioactive albumin surface coating can either be prepared by self-assembly of albumin-polymer conjugates or by postcoating of existing nanoparticles with albumin. Albumin has also been used as building block, either in its native or denatured form. Existing albumin nanoparticles are coated with polymers, which can influence the degradation of albumin or impact on the drug release. Finally, an alternative way of using albumin by denaturing the protein to generate a highly functional chain, which can be modified with polymer, has been presented. These albumin nanoparticles are designed to be extremely versatile so that they can deliver a wide variety of drugs, including traditional hydrophobic drugs, metal-based drugs and even therapeutic proteins and siRNA.

  4. Electrochromic artificial muscles based on nanoporous metal-polymer composites

    NARCIS (Netherlands)

    Detsi, E.; Onck, P. R.; De Hosson, J. T. M.

    2013-01-01

    This work shows that a nano-coating of electrochromic polymer grown onto the ligaments of nanoporous gold causes reversible dimensional and color changes during electrochemical actuation. This combination of electromechanical and optical properties opens additional avenues for the applications of ar

  5. Recent developments in polyurethane-based conducting polymer composites

    OpenAIRE

    Njuguna, James A. K.; Pielichowski, Krzysztof

    2004-01-01

    Polyurethane-based conducting composites with polyaniline, polythiophene or polypyrrole are in the class of modern macromolecular materials that combine the toughness and elasticity of polyurethane matrix with conductivity of intrinsically conducting polymers. Since the methods of preparation strongly influence the structure and properties of resulting composite/blend, this works aim at systematic description of polyurethane based conducting composites. This review has been ...

  6. Microactuators based on ion implanted dielectric electroactive polymer (EAP) membranes

    NARCIS (Netherlands)

    Dubois, Philippe; Rosset, Samuel; Koster, Sander; Stauffer, Johann; Mikhailov, Serguei; Dadras, Massoud; de Rooij, Nico-F.; Shea, Herbert

    2006-01-01

    We report on the first successfully microfabricated and tested ion implanted dielectric electroactive polymer (DEAP) actuators. Dielectric EAP (DEAP) actuators combine exceptionally high energy-density with large amplitude displacements [S. Ashley, Artificial muscles, Sci. Am. 289 (2003) 52-59: R. P

  7. The structural diversity of artificial genetic polymers.

    Science.gov (United States)

    Anosova, Irina; Kowal, Ewa A; Dunn, Matthew R; Chaput, John C; Van Horn, Wade D; Egli, Martin

    2016-02-18

    Synthetic genetics is a subdiscipline of synthetic biology that aims to develop artificial genetic polymers (also referred to as xeno-nucleic acids or XNAs) that can replicate in vitro and eventually in model cellular organisms. This field of science combines organic chemistry with polymerase engineering to create alternative forms of DNA that can store genetic information and evolve in response to external stimuli. Practitioners of synthetic genetics postulate that XNA could be used to safeguard synthetic biology organisms by storing genetic information in orthogonal chromosomes. XNA polymers are also under active investigation as a source of nuclease resistant affinity reagents (aptamers) and catalysts (xenozymes) with practical applications in disease diagnosis and treatment. In this review, we provide a structural perspective on known antiparallel duplex structures in which at least one strand of the Watson-Crick duplex is composed entirely of XNA. Currently, only a handful of XNA structures have been archived in the Protein Data Bank as compared to the more than 100 000 structures that are now available. Given the growing interest in xenobiology projects, we chose to compare the structural features of XNA polymers and discuss their potential to access new regions of nucleic acid fold space. PMID:26673703

  8. Hybrid Photonic Integration on a Polymer Platform

    Directory of Open Access Journals (Sweden)

    Ziyang Zhang

    2015-09-01

    Full Text Available To fulfill the functionality demands from the fast developing optical networks, a hybrid integration approach allows for combining the advantages of various material platforms. We have established a polymer-based hybrid integration platform (polyboard, which provides flexible optical input/ouptut interfaces (I/Os that allow robust coupling of indium phosphide (InP-based active components, passive insertion of thin-film-based optical elements, and on-chip attachment of optical fibers. This work reviews the recent progress of our polyboard platform. On the fundamental level, multi-core waveguides and polymer/silicon nitride heterogeneous waveguides have been fabricated, broadening device design possibilities and enabling 3D photonic integration. Furthermore, 40-channel optical line terminals and compact, bi-directional optical network units have been developed as highly functional, low-cost devices for the wavelength division multiplexed passive optical network. On a larger scale, thermo-optic elements, thin-film elements and an InP gain chip have been integrated on the polyboard to realize a colorless, dual-polarization optical 90° hybrid as the frontend of a coherent receiver. For high-end applications, a wavelength tunable 100Gbaud transmitter module has been demonstrated, manifesting the joint contribution from the polyboard technology, high speed polymer electro-optic modulator, InP driver electronics and ceramic electronic interconnects.

  9. Conjugated microporous polymers: design, synthesis and application.

    Science.gov (United States)

    Xu, Yanhong; Jin, Shangbin; Xu, Hong; Nagai, Atsushi; Jiang, Donglin

    2013-10-21

    Conjugated microporous polymers (CMPs) are a class of organic porous polymers that combine π-conjugated skeletons with permanent nanopores, in sharp contrast to other porous materials that are not π-conjugated and with conventional conjugated polymers that are nonporous. As an emerging material platform, CMPs offer a high flexibility for the molecular design of conjugated skeletons and nanopores. Various chemical reactions, building blocks and synthetic methods have been developed and a broad variety of CMPs with different structures and specific properties have been synthesized, driving the rapid growth of the field. CMPs are unique in that they allow the complementary utilization of π-conjugated skeletons and nanopores for functional exploration; they have shown great potential for challenging energy and environmental issues, as exemplified by their excellent performance in gas adsorption, heterogeneous catalysis, light emitting, light harvesting and electrical energy storage. This review describes the molecular design principles of CMPs, advancements in synthetic and structural studies and the frontiers of functional exploration and potential applications.

  10. Incorporation of polydiacetylene sensors into commercial polymers

    Science.gov (United States)

    Kauffman, Jennifer Susan

    Polydiacetylenes (PDAs) exhibit a chromatic response to solvents, temperature, strain and other environmental perturbations. When formed in a solid-state polymerization, the backbone of the polymer is planar and continuous pi-overlap is observed. However, when the PDA backbone is distorted by an outside force the extended conjugation is interrupted and an optical shift from blue to red is observed. By exploiting the PDAs properties within polymer systems, smart fibers and films have been created that enhance the original intention of the host. Under this umbrella, a strain sensitive polydiacetylene-polyurethane blend was created using 3 and 4-butoxycarbonylmethylurethane PDA and a medical grade polyurethane, TecoflexRTM. Additionally, a temperature sensitive material has been developed with the renewable resource polymer, polylactic acid (PLA) blended with 10,12-pentacosadiynoic acid (PCDA). Finally, PCDA has been incorporated into sodium alginate to be used as environmentally responsive fibers. To match the aqueous solubility of the alginate, the PCDA was forced into a micellular structure through heating and probe sonication. After crystallization and polymerization, the water-soluble micelles were combined with the sodium alginate and wet-spun into calcium alginate "smart" fibers. The visual colorimetric detection (blue to red) was monitored optically and quantitatively by absorbance and Raman spectroscopy.

  11. Numerical solution of the polymer system

    Energy Technology Data Exchange (ETDEWEB)

    Haugse, V.; Karlsen, K.H.; Lie, K.-A.; Natvig, J.R.

    1999-05-01

    The paper describes the application of front tracking to the polymer system, an example of a nonstrictly hyperbolic system. Front tracking computes piecewise constant approximations based on approximate Remain solutions and exact tracking of waves. It is well known that the front tracking method may introduce a blow-up of the initial total variation for initial data along the curve where the two eigenvalues of the hyperbolic system are identical. It is demonstrated by numerical examples that the method converges to the correct solution after a finite time that decreases with the discretization parameter. For multidimensional problems, front tracking is combined with dimensional splitting and numerical experiments indicate that large splitting steps can be used without loss of accuracy. Typical CFL numbers are in the range of 10 to 20 and comparisons with the Riemann free, high-resolution method confirm the high efficiency of front tracking. The polymer system, coupled with an elliptic pressure equation, models two-phase, tree-component polymer flooding in an oil reservoir. Two examples are presented where this model is solved by a sequential time stepping procedure. Because of the approximate Riemann solver, the method is non-conservative and CFL members must be chosen only moderately larger than unity to avoid substantial material balance errors generated in near-well regions after water breakthrough. Moreover, it is demonstrated that dimensional splitting may introduce severe grid orientation effects for unstable displacements that are accentuated for decreasing discretization parameters. 9 figs., 2 tabs., 26 refs.

  12. ORGANOSILANE POLYMERS:OXIDATION-CROSSLINKABLE CYCLOTETRAMETHYLENESILYLENE POLYMER AND COPOLYMERS

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xinghua; Robert West

    1987-01-01

    Polysilane polymers containing cyclotetramethylenesilylene units were synthesized by sodium coupling of diorganodichlorosilanes in toluene. These polymers are soluble in common solvents, can be formed into a variety of shapes by molding, casting, coating or potting. They can be crosslinked by irradiation and oxidation at moderate or room temperature.

  13. Thermoresponsive Polymers for Nuclear Medicine: Which Polymer Is the Best?

    Science.gov (United States)

    Sedláček, Ondřej; Černoch, Peter; Kučka, Jan; Konefal, Rafał; Štěpánek, Petr; Vetrík, Miroslav; Lodge, Timothy P; Hrubý, Martin

    2016-06-21

    Thermoresponsive polymers showing cloud point temperatures (CPT) in aqueous solutions are very promising for the construction of various systems in biomedical field. In many of these applications these polymers get in contact with ionizing radiation, e.g., if they are used as carriers for radiopharmaceuticals or during radiation sterilization. Despite this fact, radiosensitivity of these polymers is largely overlooked to date. In this work, we describe the effect of electron beam ionizing radiation on the physicochemical and phase separation properties of selected thermoresponsive polymers with CPT between room and body temperature. Stability of the polymers to radiation (doses 0-20 kGy) in aqueous solutions increased in the order poly(N-vinylcaprolactam) (PVCL, the least stable) ≪ poly[N-(2,2-difluoroethyl)acrylamide] (DFP) polymer radiotherapeutics and sterilization of biomedical systems, cause significant increase in molecular weight due to cross-linking (except for POX, where this effect is weak). In the case of PVCL irradiated with low doses, the increase in molecular weight induced an increase in the CPT of the polymer. For PNIPAM and DFP, there is strong chain hydrophilization leading to an increase in CPT. From this perspective, POX is the most suitable polymer for the construction of delivery systems that experience exposure to radiation, while PVCL is the least suitable and PNIPAM and DFP are suitable only for low radiation demands.

  14. Thermoresponsive Polymers for Nuclear Medicine: Which Polymer Is the Best?

    Science.gov (United States)

    Sedláček, Ondřej; Černoch, Peter; Kučka, Jan; Konefal, Rafał; Štěpánek, Petr; Vetrík, Miroslav; Lodge, Timothy P; Hrubý, Martin

    2016-06-21

    Thermoresponsive polymers showing cloud point temperatures (CPT) in aqueous solutions are very promising for the construction of various systems in biomedical field. In many of these applications these polymers get in contact with ionizing radiation, e.g., if they are used as carriers for radiopharmaceuticals or during radiation sterilization. Despite this fact, radiosensitivity of these polymers is largely overlooked to date. In this work, we describe the effect of electron beam ionizing radiation on the physicochemical and phase separation properties of selected thermoresponsive polymers with CPT between room and body temperature. Stability of the polymers to radiation (doses 0-20 kGy) in aqueous solutions increased in the order poly(N-vinylcaprolactam) (PVCL, the least stable) ≪ poly[N-(2,2-difluoroethyl)acrylamide] (DFP) polymer radiotherapeutics and sterilization of biomedical systems, cause significant increase in molecular weight due to cross-linking (except for POX, where this effect is weak). In the case of PVCL irradiated with low doses, the increase in molecular weight induced an increase in the CPT of the polymer. For PNIPAM and DFP, there is strong chain hydrophilization leading to an increase in CPT. From this perspective, POX is the most suitable polymer for the construction of delivery systems that experience exposure to radiation, while PVCL is the least suitable and PNIPAM and DFP are suitable only for low radiation demands. PMID:27238593

  15. Radiation Synthesis of Superabsorbent Polymers Based on Natural Polymers

    International Nuclear Information System (INIS)

    The objectives of proposed research contract were first synthesize superabsorbent polymers based on natural polymers to be used as disposable diapers and soil conditioning materials in agriculture, horticulture and other super adsorbent using industries. We have planned to use the natural polymers; locust beam gum, tara gum, guar gum and sodium alginate on the preparation of natural superabsorbent polymers(SAP). The aqueous solution of natural polymers and their blends with trace amount of monomer and cross-linking agents will be irradiated in paste like conditions by gamma rays for the preparation of cross-linked superabsorbent systems. The water absorption and deswellling capacity of prepared super adsorbents and retention capacity, absorbency under load, suction power, swelling pressure and pet-rewet properties will be determined. Use of these materials instead of synthetic super absorbents will be examined by comparing the performance of finished products. The experimental studies achieved in the second year of project mainly on the effect of radiation on the chemistry of sodium alginate polymers in different irradiation conditions and structure-property relationship particularly with respect to radiation induced changes on the molecular weight of natural polymers and preliminary studies on the synthesis of natural-synthetic hydride super adsorbent polymers were given in details

  16. Nanoparticles as strengthening agents in polymer systems

    Science.gov (United States)

    Shahid, Naureen

    2005-11-01

    Carboxylate-substituted alumina nanoparticles are produced solvent free using mechanical shear. The general nature of this method has been demonstrated for L-lysine-, stearate, and p-hydroxybenzoate-derived materials. The reaction rate and particle size is controlled by a combination of temperature and shear rate. The nanoparticles are spectroscopically equivalent to those reported from aqueous syntheses, however, the average particle size can be decreased and the particle size distribution narrowed depending on the reaction conditions. Lysine and p-hydroxybenzoato alumoxanes have been introduced in carbon fiber reinforced epoxide resin composites. Different preparation conditions have been studied to obtain composite with enhanced performances that are ideal for the motor sports and aerospace industries. A new composite material has been fabricated utilizing surface-modified carboxylate alumoxane nanoparticles and the biodegradable polymer poly(propylene fumarate)/poly(propylene fumarate)-diacrylate (PPF/PPF-DA). For this study, composites were prepared using various functional groups including: a surfactant alumoxane to enhance nanoparticle dispersion into the polymer; an activated-alumoxane to enhance nanoparticle interaction with the polymer matrix; a mixed alumoxane containing both activated and surfactant groups. Nanocomposites prepared with all types of alumoxane, as well as blank polymer resin and unmodified boehmite, underwent mechanical testing and were characterized by SEM and microprobe analysis. A nanocomposite composed of mixed alumoxane nanoparticles dispersed in PPF/PPF-DA exhibited increased flexural modulus compared to polymer resin alone, and a significant enhancement over both the activated and surfacted alumoxanes. Boric acid is used as the cross-linking agent in oil well drilling industry even though the efficacy of the borate ion, [B(OH)4]- , as a cross-linking agent is poor. The reaction product of boric acid and the polysaccharide guaran

  17. All Polymer Micropump

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen

    2008-01-01

    of the substrate, the PEDOT is integrated into the non-conductive polymer. The result is a material that retains the good conductivity of PEDOT, but gains the mechanical stability of the substrate. The best results were obtained for PEDOTjPMMA. The new mechanically stable PEDOTjPMMA was micro-patterned using clean...... (ACEO) micropump. The ACEO pump consists of an array of interdigitated small and large PEDOTjPMMA encapsulated in a polyurethane (PUR) channel system. The pumping velocity was detected using fluorescent microspheres and a confocal microscope. The pump characteristics resembled those of pumps based...

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

    Science.gov (United States)

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

    2011-01-01

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

  19. Controlled Synthesis of Polymer Brushes via Polymer Single Crystal Templates

    Science.gov (United States)

    Zhou, Tian

    A novel synthetic method of polymer brushes using polymer single crystals (PSCs) as solid-state templates is introduced in this study. PSC has a quasi-2D lamellae structure with polymer chains fold back-and-forth perpendicular to the lamellae surfaces. During crystallization, the chain ends are excluded from the unit cell onto the lamellae surfaces, which makes the material extremely versatile in its functionality. Such structure holds the unique capability to harvest nanoparticles, or being immobilized onto macroscopic flat surfaces. After dissolving PSCs in good solvent, polymer brushes are chemically tethered on either nanoparticles or flat macroscopic surfaces. Because the chain-folding structure can be conveniently tailored by changing the molecular weight of polymer and the crystallization temperature, the thickness, grafting density and morphology of resulted polymer brushes can be precisely controlled. As a model system, poly(?-caprolactone) with thiol or alkoxysilane terminal groups was used, and polymer brushes were successfully prepared on both nanoparticles and glass/Au flat surfaces. The structure-property relationships of the as-prepared polymer brushes were studied in detail using multiple characterization techniques. First of all, when functionalizing nanoparticles, by engineering the chain-folding structure of the PSCs, interesting complex nanostructures can be formed by nanoparticles including Janus nanoparticles and nanoparticle dimers. These unique structures render hybrid nanoparticles very interesting responsive behavior which have been studied in detail in this dissertation. When grafted onto a flat surface on the other hand, not only the molecular weight and grafting density can be precisely controlled, the tethering points of a single polymer chain can also be conveniently tailored, resulting polymer brushes with either tail or loop structures. Such difference in brush structure can significantly alter the properties of functional surface

  20. Compatibility of polymers and chemical oxidants for enhanced groundwater remediation.

    Science.gov (United States)

    Smith, Megan M; Silva, Jeff A K; Munakata-Marr, Junko; McCray, John E

    2008-12-15

    Polymer floods provide a promising method to more effectively deliver conventional groundwater treatment agents to organic contaminants distributed within heterogeneous aquifer systems. Combinations of nontoxic polymers (xanthan and hydrolyzed polyacrylamide) and common chemical oxidants (potassium permanganate and sodium persulfate) were investigated to determine the suitability of these mixtures for polymer-enhanced in situ chemical oxidation applications. Oxidant demand and solution viscosity were utilized as initial measures of chemical compatibility. After 72 h of reaction with both test oxidants, solution viscosities in mixtures containing hydrolyzed polyacrylamide were decreased by more than 90% (final viscosities approximately 2 cP), similar to the 95% viscosity loss (final viscosities approximately 1 cP, near that of water) observed in xanthan/persulfate experiments. In contrast, xanthan solutions exposed to potassium permanganate preserved 60-95% of initial viscosity after 72 h. Permanganate depletion in xanthan-containing experiments ranged from 2% to 24% over the same test period. Although oxidant consumption in xanthan/permanganate solutions appeared to be correlated with increasing xanthan concentrations, solutions of up to 2000 mg/L xanthan did not inhibit permanganate from oxidizing a dissolved-phase test contaminant (tetrachloroethene, PCE) in xanthan solution. These advantageous characteristics (high viscosity retention, moderate oxidant demand, and lack of competitive effects on PCE oxidation rate) render xanthan/permanganate the most compatible polymer/oxidant combination of those tested for remediation by polymer-enhanced chemical oxidation. PMID:19174907

  1. Diffusive mixing of polymers investigated by Raman microspectroscopy and microrheology.

    Science.gov (United States)

    Jonás, A; De Luca, A C; Pesce, G; Rusciano, G; Sasso, A; Caserta, S; Guido, S; Marrucci, G

    2010-09-01

    Diffusive mixing in a model polymer blend of limited miscibility (i.e., the pair polydimethylsiloxane/polyisobutene) is investigated. The diffusion process is followed in the actual droplet-based microstructure of the polymer blend, as opposed to the ideal planar geometry used in previous studies (Brochard et al. Macromolecules 1983, 16, 1638; Composto et al. Nature 1987, 328, 234). In our experiments we combine Raman microspectroscopy and video particle-tracking microrheology. The first technique allows us to monitor local concentration of the two polymers with high spatial resolution both inside and outside a micrometer-size droplet of the dispersed phase. In addition, microrheology enables to follow how the local viscosity inside the droplet changes during the diffusion. The polymer viscosity inside the droplet is determined by video tracking the Brownian motion of a polystyrene bead microinjected into the droplet. The microspectroscopic and microrheological data are combined to estimate the concentration dependence of the monomer friction factor of the two species, which is a key parameter to calculate the interdiffusion coefficient D. Numerical calculations based on such concentration-dependent interdiffusion coefficient D and several alternative models of the polymer diffusion are compared to the experimental concentration profiles. A satisfactory agreement is found for the so-called "slow theory" (Brochard et al.). A phenomenological model improving the agreement of the model with the experimental data is also presented.

  2. High-Performance Non-Fullerene Polymer Solar Cells Based on a Pair of Donor-Acceptor Materials with Complementary Absorption Properties.

    Science.gov (United States)

    Lin, Haoran; Chen, Shangshang; Li, Zhengke; Lai, Joshua Yuk Lin; Yang, Guofang; McAfee, Terry; Jiang, Kui; Li, Yunke; Liu, Yuhang; Hu, Huawei; Zhao, Jingbo; Ma, Wei; Ade, Harald; Yan, He

    2015-12-01

    A 7.3% efficiency non-fullerene polymer solar cell is realized by combining a large-bandgap polymer PffT2-FTAZ-2DT with a small-bandgap acceptor IEIC. The complementary absorption of donor polymer and small-molecule acceptor is responsible for the high-performance of the solar-cell device. This work provides important guidance to improve the performance of non-fullerene polymer solar cells.

  3. Optical properties of polymer nanocomposites

    Indian Academy of Sciences (India)

    S Srivastava; M Haridas; J K Basu

    2008-06-01

    Nanomaterials have emerged as an area of interest motivated by potential applications of these materials in light emitting diodes, solar cells, polarizers, light – stable colour filters, optical sensors, optical data communication and optical data storage. Nanomaterials are of particular interest as they combine the properties of two or more different materials with the possibility of possessing novel mechanical, electronic or chemical behaviour. Understanding and tuning such effects could lead to hybrid devices based on these nanocomposites with improved optical properties. We have prepared polymer nanocomposites of well-defined compositions and studied the optical properties of powders and their thin films. UV-vis absorption spectroscopy on nanocomposite powders and spectroscopic ellipsometry measurements on thin films was used to study the effect of interfacial morphology, interparticle spacing and finite size effects on optical properties of nanocomposites. Systematic shift in the imaginary part of the dielectric function can be seen with variation in size and fraction of the gold nanoparticle. The thickness of the film also plays a significant role in the tunability of the optical spectra.

  4. Differential scanning calorimetry (DSC) of semicrystalline polymers.

    Science.gov (United States)

    Schick, C

    2009-11-01

    Differential scanning calorimetry (DSC) is an effective analytical tool to characterize the physical properties of a polymer. DSC enables determination of melting, crystallization, and mesomorphic transition temperatures, and the corresponding enthalpy and entropy changes, and characterization of glass transition and other effects that show either changes in heat capacity or a latent heat. Calorimetry takes a special place among other methods. In addition to its simplicity and universality, the energy characteristics (heat capacity C(P) and its integral over temperature T--enthalpy H), measured via calorimetry, have a clear physical meaning even though sometimes interpretation may be difficult. With introduction of differential scanning calorimeters (DSC) in the early 1960s calorimetry became a standard tool in polymer science. The advantage of DSC compared with other calorimetric techniques lies in the broad dynamic range regarding heating and cooling rates, including isothermal and temperature-modulated operation. Today 12 orders of magnitude in scanning rate can be covered by combining different types of DSCs. Rates as low as 1 microK s(-1) are possible and at the other extreme heating and cooling at 1 MK s(-1) and higher is possible. The broad dynamic range is especially of interest for semicrystalline polymers because they are commonly far from equilibrium and phase transitions are strongly time (rate) dependent. Nevertheless, there are still several unsolved problems regarding calorimetry of polymers. I try to address a few of these, for example determination of baseline heat capacity, which is related to the problem of crystallinity determination by DSC, or the occurrence of multiple melting peaks. Possible solutions by using advanced calorimetric techniques, for example fast scanning and high frequency AC (temperature-modulated) calorimetry are discussed.

  5. COUPLING THE ALKALINE-SURFACTANT-POLYMER TECHNOLOGY AND THE GELATION TECHNOLOGY TO MAXIMIZE OIL PRODUCTION

    Energy Technology Data Exchange (ETDEWEB)

    Malcolm Pitts; Jie Qui; Dan Wilson; Phil Dowling

    2004-05-01

    Gelation technologies have been developed to provide more efficient vertical sweep efficiencies for flooding naturally fractured oil reservoirs or more efficient areal sweep efficiency those with high permeability contrast ''thief zones''. The field proven alkaline-surfactant-polymer technology economically recovers 15% to 25% OOIP more oil than waterflooding in the swept pore space of an oil reservoir. However, alkaline-surfactant-polymer technology is not amenable to the naturally fractured reservoirs or those with thief zones because much of the injected solution bypasses the target pore space containing oil. The objective of this work is to investigate whether combining these two technologies could broaden the applicability of alkaline-surfactant-polymer flooding into these reservoirs. Fluid-fluid interaction with different gel chemical compositions and alkaline-surfactant-polymer solution with pH values ranging from 9.2 to 12.9 have been tested. Aluminum-polyacrylamide gels are not stable to alkaline-surfactant-polymer solutions at any pH. Chromium--polyacrylamide gels with polymer to chromium ion ratios of 25 or greater were stable to alkaline-surfactant-polymer solutions if solution pH was 10.6 or less. When the polymer to chromium ion was 15 or less, chromium-polyacrylamide gels were stable to alkaline-surfactant-polymer solutions with pH values up to 12.9. Chromium-xanthan gum gels were stable to alkaline-surfactant-polymer solutions with pH values of 12.9 at the polymer to chromium ion ratios tested. Silicate-polyacrylamide, resorcinol-formaldehyde, and sulfomethylated resorcinol-formaldehyde gels were also stable to alkaline-surfactant-polymer solutions with pH values ranging from 9.2 to 12.9. Iron-polyacrylamide gels were immediately destroyed when contacted with any of the alkaline-surfactant-polymer solutions with pH values of 9.2 to 12.9.

  6. Graphene/Polymer Nanocomposites

    Science.gov (United States)

    Macosko, Chris

    2010-03-01

    Graphite has attracted large attention as a reinforcement for polymers due to its ability to modify electrical conductivity, mechanical and gas barrier properties of host polymers and its potentially lower cost than carbon nanotubes. If graphite can be exfoliated into atomically thin graphene sheets, it is possible to achieve the highest property enhancements at the lowest loading. However, small spacing and strong van der Waals forces between graphene layers make exfoliation of graphite via conventional composite manufacturing strategies challenging. Recently, two different approaches to obtain exfoliated graphite prior to blending were reported: thermal treatment (Schniepp et al., JACS 2006) and chemical modification (Stankovich et al., J Mat Chem 2006). Both start from graphite oxide. We will describe and evaluate these exfoliation approaches and the methods used to produce graphene reinforced thermoplastics, particularly polyester, polycarbonate and polyurethane nanocomposites. Three different dispersion methods - melt blending, solution mixing and in-situ polymerization -- are compared. Characterization of dispersion quality is illustrated with TEM, rheology and in electrical conductivity, tensile modulus and gas barrier property improvement.

  7. Polymer dye lasers

    DEFF Research Database (Denmark)

    Balslev, Søren

    2006-01-01

    , elektronstrålelithografi og Röntgenstrålelithografi. Andre polymerer er også blevet formgivet via ”nanoimprint” lithografi for at skabe laserresonatorer. En række lasere, både baseret på et flydende forstærkningsmedium og et faststof forstærkningsrmedium er blevet udviklet. Laserne giver både lys i flere ”modes” og i een......Formålet med dette Ph.D. arbejde har været at udvikle miniaturiserede polymer farvestoflasere, egnet til at blive integreret i mikrochips som også indeholder andre polymerstrukturer – som for eksempel kan findes i ”Laboratorie-på-en-chip” kredsløb. Lasernes funktion skal være at levere lys til...... meget følsomme sensorformål, og at undgå at skulle opliniere eksterne lyskilder til sensorer på polymerchips. En enkelt type gennemsigtig ”resist” (SU-8) er blevet brugt til at udvikle en række laserresonatorer i polymer. ”Resisten” er blevet formgivet via en række lithografiske teknikker: UV lithografi...

  8. Polymer-based photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Edrington, A.C.; Urbas, A.M.; Fink, Y.; Thomas, E.L. [Massachusetts Inst. of Tech., Cambridge (United States). Dept. of Materials Science and Engineering; DeRege, P. [Firmenich, Inc., Port Newark, NJ (United States); Chen, C.X.; Swager, T.M. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Chemistry; Hadjichristidis, N. [Athens Univ. (Greece). Dept. of Chemistry; Xenidou, M.; Fetters, L.J. [ExxonMobil Research Corp., Annandale, NJ (United States); Joannopoulos, J.D. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Physics

    2001-03-16

    The development of polymers as photonic crystals is highlighted, placing special emphasis on self-assembled block copolymers. 1D self-assembled multilayers as well as 2D and 3D self-assembled structures are examined, then intricate block polymer structures such as that shown in the Figure are discussed as are birefringent multilayer and elastomeric films. (orig.)

  9. Wood and concrete polymer composites

    International Nuclear Information System (INIS)

    There are several ways to prepare and use wood and concrete polymer composites. The most important improvements in the case of concrete polymer composites are obtained for compressive and tensile strengths. The progress in this field in United States and other countries is discussed in this rview. (M.S.)

  10. Polymer highlights for September 1975

    Energy Technology Data Exchange (ETDEWEB)

    Hammon, H.G.; Althouse, L.P.; Buckner, A.T.; McKinley, B.; Walkup, C.M.; Rinde, J.; Lorensen, L.L.; Cady, W.E.; Caley, L.E.

    1988-12-15

    Research programs in polymer chemistry are briefly described. The following polymers are under investigation for use as adhesives, nozzles, insulators, or fluid cushions: urethanes, teflon, TFE, Tefzel, Ryton, H Resin, Imidite 2803, PPQ, KELF 800, and KELF 5500. Areas of research application include geothermal and solar energy fields. (CBS)

  11. All-Polymer Electrochemical Sensors

    DEFF Research Database (Denmark)

    Kafka, Jan Robert

    This thesis presents fabrication strategies to produce different types of all-polymer electrochemical sensors based on electrodes made of the highly conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT). Three different systems are presented, fabricated either by using microdrilling or by hot...

  12. Fifty years of polymer science

    NARCIS (Netherlands)

    Prez, Du Filip; Hoogenboom, Richard; Klumperman, Bert; Meier, Michael; Monteiro, Michael; Müller, Alejandro; Vancso, Julius

    2015-01-01

    The European Polymer Journal (EPJ) has been serving the scientific community for 50 years, which makes it one of the older macromolecular journals with a broad focus. Since its launch 50 years ago, EPJ has provided a distinguished forum for publications in polymer research, including chemistry, phys

  13. Review of polymer MEMS micromachining

    Science.gov (United States)

    Kim, Brian J.; Meng, Ellis

    2016-01-01

    The development of polymer micromachining technologies that complement traditional silicon approaches has enabled the broadening of microelectromechanical systems (MEMS) applications. Polymeric materials feature a diverse set of properties not present in traditional microfabrication materials. The investigation and development of these materials have opened the door to alternative and potentially more cost effective manufacturing options to produce highly flexible structures and substrates with tailorable bulk and surface properties. As a broad review of the progress of polymers within MEMS, major and recent developments in polymer micromachining are presented here, including deposition, removal, and release techniques for three widely used MEMS polymer materials, namely SU-8, polyimide, and Parylene C. The application of these techniques to create devices having flexible substrates and novel polymer structural elements for biomedical MEMS (bioMEMS) is also reviewed.

  14. Neutron scattering in polymer physics

    Science.gov (United States)

    Richter, D.

    2000-03-01

    By example this short review presents recent scientific advances which were achieved by the application of neutron scattering to polymer systems, thereby, keeping in mind also practical applications. We first focus on experiments on the structure and morphology of polymer systems covering conformational studies, investigations on polymer-microemulsions systems and the observation of aggregation states in living polymerization. Thereafter, we present recent results in the field of polymer dynamics. We begin with local motions which are behind the classical relaxation processes in polymer melts. Then we relate to universal dynamics, we address the Rouse model and its limits, present new results on the dynamic miscibility in blends and display the latest investigations on entanglement dynamics. Finally, we report first observations of ripplon excitations of phase boundaries in diblock copolymer melts.

  15. Controlled release from recombinant polymers.

    Science.gov (United States)

    Price, Robert; Poursaid, Azadeh; Ghandehari, Hamidreza

    2014-09-28

    Recombinant polymers provide a high degree of molecular definition for correlating structure with function in controlled release. The wide array of amino acids available as building blocks for these materials lend many advantages including biorecognition, biodegradability, potential biocompatibility, and control over mechanical properties among other attributes. Genetic engineering and DNA manipulation techniques enable the optimization of structure for precise control over spatial and temporal release. Unlike the majority of chemical synthetic strategies used, recombinant DNA technology has allowed for the production of monodisperse polymers with specifically defined sequences. Several classes of recombinant polymers have been used for controlled drug delivery. These include, but are not limited to, elastin-like, silk-like, and silk-elastinlike proteins, as well as emerging cationic polymers for gene delivery. In this article, progress and prospects of recombinant polymers used in controlled release will be reviewed.

  16. Polymer research by neutron scattering

    International Nuclear Information System (INIS)

    Polymer physics aims on an understanding of the macroscopic behavior of polymer systems on the basis of their molecular structure and dynamics. For this purpose neutrons serve as a unique probe, allowing a simultaneous investigation of polymer structure and dynamics on a molecular scale. Furthermore, hydrogen deuterium exchange facilitates molecular labeling and offers the possibility to observe selected chains or chain parts in dense systems. Neutron small angle scattering reveals information on the conformation and possible aggregation of polymer chains. Data on linear and star like molecules are shown as examples. High resolution neutron spin-echospectroscopy observes the molecular dynamics of long chain molecules. Results on the large scale motion of chins in polymer melts are presented. finally, experiments on chain relaxation close to the glass transition are displayed. Three distinctly different relaxation processes are revealed. (author)

  17. Polymers for Cardiovascular Stent Coatings

    Directory of Open Access Journals (Sweden)

    Anne Strohbach

    2015-01-01

    Full Text Available Polymers have found widespread applications in cardiology, in particular in coronary vascular intervention as stent platforms (scaffolds and coating matrices for drug-eluting stents. Apart from permanent polymers, current research is focussing on biodegradable polymers. Since they degrade once their function is fulfilled, their use might contribute to the reduction of adverse events like in-stent restenosis, late stent-thrombosis, and hypersensitivity reactions. After reviewing current literature concerning polymers used for cardiovascular applications, this review deals with parameters of tissue and blood cell functions which should be considered to evaluate biocompatibility of stent polymers in order to enhance physiological appropriate properties. The properties of the substrate on which vascular cells are placed can have a large impact on cell morphology, differentiation, motility, and fate. Finally, methods to assess these parameters under physiological conditions will be summarized.

  18. Color formation in irradiated polymers

    Science.gov (United States)

    Clough, R. L.; Gillen, K. T.; Malone, G. M.; Wallace, J. S.

    1996-11-01

    Discoloration is a problem in the radiation processing of polymers (such as radiation sterilization), and also in emerging applications in which optical-property materials are used in radiation environments (such as scintillation detectors). We have completed a survey of 17 different types of optical polymers, in which it is found that these materials form both permanent and annealable color centers, but in very different magnitudes and ratios. Optical absorption spectra of irradiated polymers both immediately after irradiation and following different time periods of annealing are provided. Also provided are tables showing rank ordering of the relative resistance of different polymer types to induced discoloration. It is found that the extent of radiation-induced discoloration of polymers has little or no dependence on whether the macromolecule is aromatic or aliphatic, and shows no correlation with the relative extent of radiation-induced mechanical property change. Examples of the influence of stabilizer additives on the extent of discoloration are discussed.

  19. Direct Photopatterning of Electrochromic Polymers

    DEFF Research Database (Denmark)

    Jensen, Jacob; Dyer, Aubrey L.; Shen, D. Eric;

    2013-01-01

    Propylenedioxythiophene (ProDOT) polymers are synthesized using an oxidative polymerization route that results in methacrylate substituted poly(ProDOTs) having a Mn of 10–20 kDa wherein the methacrylate functionality constitutes from 6 to 60% of the total monomer units. Solutions of these polymers...... show excellent film forming abilities, with thin films prepared using both spray‐casting and spin‐coating. These polymers are demonstrated to crosslink upon UV irradiation at 350 nm, in the presence of an appropriate photoinitiator, to render the films insoluble to common organic solvents....... Electrochemical, spectroelectrochemical, and colorimetric analyses of the crosslinked polymer films are performed to establish that they retain the same electrochromic qualities as the parent polymers with no detriment to the observed properties. To demonstrate applicability for multi‐film processing...

  20. Fundamental studies of polymer filtration

    Energy Technology Data Exchange (ETDEWEB)

    Smith, B.F.; Lu, M.T.; Robison, T.W.; Rogers, Y.C.; Wilson, K.V.

    1998-12-31

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The objectives of this project were (1) to develop an enhanced fundamental understanding of the coordination chemistry of hazardous-metal-ion complexation with water-soluble metal-binding polymers, and (2) to exploit this knowledge to develop improved separations for analytical methods, metals processing, and waste treatment. We investigated features of water-soluble metal-binding polymers that affect their binding constants and selectivity for selected transition metal ions. We evaluated backbone polymers using light scattering and ultrafiltration techniques to determine the effect of pH and ionic strength on the molecular volume of the polymers. The backbone polymers were incrementally functionalized with a metal-binding ligand. A procedure and analytical method to determine the absolute level of functionalization was developed and the results correlated with the elemental analysis, viscosity, and molecular size.

  1. Grafted polymer under shear flow

    Science.gov (United States)

    Kumar, Sanjiv; Foster, Damien P.; Giri, Debaprasad; Kumar, Sanjay

    2016-04-01

    A self-attracting-self-avoiding walk model of polymer chain on a square lattice has been used to gain an insight into the behaviour of a polymer chain under shear flow in a slit of width L. Using exact enumeration technique, we show that at high temperature, the polymer acquires the extended state continuously increasing with shear stress. However, at low temperature the polymer exhibits two transitions: a transition from the coiled to the globule state and a transition to a stem-flower like state. For a chain of finite length, we obtained the exact monomer density distributions across the layers at different temperatures. The change in density profile with shear stress suggests that the polymer under shear flow can be used as a molecular gate with potential application as a sensor.

  2. Review of polymer MEMS micromachining

    International Nuclear Information System (INIS)

    The development of polymer micromachining technologies that complement traditional silicon approaches has enabled the broadening of microelectromechanical systems (MEMS) applications. Polymeric materials feature a diverse set of properties not present in traditional microfabrication materials. The investigation and development of these materials have opened the door to alternative and potentially more cost effective manufacturing options to produce highly flexible structures and substrates with tailorable bulk and surface properties. As a broad review of the progress of polymers within MEMS, major and recent developments in polymer micromachining are presented here, including deposition, removal, and release techniques for three widely used MEMS polymer materials, namely SU-8, polyimide, and Parylene C. The application of these techniques to create devices having flexible substrates and novel polymer structural elements for biomedical MEMS (bioMEMS) is also reviewed. (topical review)

  3. Accelerated Characterization of Polymer Properties

    Energy Technology Data Exchange (ETDEWEB)

    R. Wroczynski; l. Brewer; D. Buckley; M. Burrell; R. Potyrailo

    2003-07-30

    This report describes the efforts to develop a suite of microanalysis techniques that can rapidly measure a variety of polymer properties of industrial importance, including thermal, photo-oxidative, and color stability; as well as ductility, viscosity, and mechanical and antistatic properties. Additional goals of the project were to direct the development of these techniques toward simultaneous measurements of multiple polymer samples of small size in real time using non-destructive and/or parallel or rapid sequential measurements, to develop microcompounding techniques for preparing polymers with additives, and to demonstrate that samples prepared in the microcompounder could be analyzed directly or used in rapid off-line measurements. These enabling technologies are the crucial precursors to the development of high-throughput screening (HTS) methodologies for the polymer additives industry whereby the rate of development of new additives and polymer formulations can be greatly accelerated.

  4. Polymer in Agriculture: a Review

    Directory of Open Access Journals (Sweden)

    Francesco Puoci

    2008-01-01

    Full Text Available In agricultural field, polymers are widely used for many applications. Although they were used, in the first time, just as structural materials (inhert polymers, in the last decades functionalized polymers revolutionized the agricultural and food industry with new tools for several applications. Smart polymeric materials and smart delivery systems helped the agricultural industryto combat viruses and other crop pathogens, functionalized polymers were used to increase the efficiency of pesticides and herbicides, allowing lower doses to be used and to indirectly protect the environment through filters or catalysts to reduce pollution and clean-up existing pollutants. This report will review the key aspects of used polymers in agricultural area, highlighting current research in this field and the future impacts they may have.

  5. The role of electron affinity in determining whether fullerenes catalyze or inhibit photooxidation of polymers for solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Hoke, Eric T.; Sachs-Quintana, I.T.; Kauvar, Isaac; Mateker, William R.; Peters, Craig H.; McGehee, Michael D. [Department of Material Science and Engineering, Stanford University, 476 Lomita Mall, Stanford, CA 94305 (United States); Lloyd, Matthew T.; Nardes, Alexandre M.; Kopidakis, Nikos [National Renewable Energy Laboratory, 1617 Cole Blvd, Golden, CO 80401 (United States)

    2012-11-15

    Understanding the stability and degradation mechanisms of organic solar materials is critically important to achieving long device lifetimes. Here, an investigation of the photodegradation of polymer:fullerene blend films exposed to ambient conditions for a variety of polymer and fullerene derivative combinations is presented. Despite the wide range in polymer stabilities to photodegradation, the rate of irreversible polymer photobleaching in blend films is found to consistently and dramatically increase with decreasing electron affinity of the fullerene derivative. Furthermore, blends containing fullerenes with the smallest electron affinities photobleached at a faster rate than films of the pure polymer. These observations can be explained by a mechanism where both the polymer and fullerene donate photogenerated electrons to diatomic oxygen to form the superoxide radical anion which degrades the polymer. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. The Role of Electron Affinity in Determining Whether Fullerenes Catalyze or Inhibit Photooxidation of Polymers for Solar Cells

    KAUST Repository

    Hoke, Eric T.

    2012-05-21

    Understanding the stability and degradation mechanisms of organic solar materials is critically important to achieving long device lifetimes. Here, an investigation of the photodegradation of polymer:fullerene blend fi lms exposed to ambient conditions for a variety of polymer and fullerene derivative combinations is presented. Despite the wide range in polymer stabilities to photodegradation, the rate of irreversible polymer photobleaching in blend fi lms is found to consistently and dramatically increase with decreasing electron affi nity of the fullerene derivative. Furthermore, blends containing fullerenes with the smallest electron affi nities photobleached at a faster rate than fi lms of the pure polymer. These observations can be explained by a mechanism where both the polymer and fullerene donate photogenerated electrons to diatomic oxygen to form the superoxide radical anion which degrades the polymer. © 2012 WILEY-VCH Verlag GmbH & Co.

  7. EDITORIAL: Electroactive polymer materials

    Science.gov (United States)

    Bar-Cohen, Yoseph; Kim, Kwang J.; Ryeol Choi, Hyouk; Madden, John D. W.

    2007-04-01

    Imitating nature's mechanisms offers enormous potential for the improvement of our lives and the tools we use. This field of the study and imitation of, and inspiration from, nature's methods, designs and processes is known as biomimetics. Artificial muscles, i.e. electroactive polymers (EAPs), are one of the emerging technologies enabling biomimetics. Polymers that can be stimulated to change shape or size have been known for many years. The activation mechanisms of such polymers include electrical, chemical, pneumatic, optical and magnetic. Electrical excitation is one of the most attractive stimulators able to produce elastic deformation in polymers. The convenience and practicality of electrical stimulation and the continual improvement in capabilities make EAP materials some of the most attractive among activatable polymers (Bar-Cohen Y (ed) 2004 Electroactive Polymer (EAP) Actuators as Artificial Muscles—Reality, Potential and Challenges 2nd edn, vol PM136 (Bellingham, WA: SPIE Press) pp 1-765). As polymers, EAP materials offer many appealing characteristics that include low weight, fracture tolerance and pliability. Furthermore, they can be configured into almost any conceivable shape and their properties can be tailored to suit a broad range of requirements. These capabilities and the significant change of shape or size under electrical stimulation while being able to endure many cycles of actuation are inspiring many potential possibilities for EAP materials among engineers and scientists in many different disciplines. Practitioners in biomimetics are particularly excited about these materials since they can be used to mimic the movements of animals and insects. Potentially, mechanisms actuated by EAPs will enable engineers to create devices previously imaginable only in science fiction. For many years EAP materials received relatively little attention due to their poor actuation capability and the small number of available materials. In the last fifteen

  8. Polymers – A New Open Access Scientific Journal on Polymer Science

    Directory of Open Access Journals (Sweden)

    Shu-Kun Lin

    2009-12-01

    Full Text Available Polymers is a new interdisciplinary, Open Access scientific journal on polymer science, published by Molecular Diversity Preservation International (MDPI. This journal welcomes manuscript submissions on polymer chemistry, macromolecular chemistry, polymer physics, polymer characterization and all related topics. Both synthetic polymers and natural polymers, including biopolymers, are considered. Manuscripts will be thoroughly peer-reviewed in a timely fashion, and papers will be published, if accepted, within 6 to 8 weeks after submission. [...

  9. SULFUR POLYMER ENCAPSULATION

    International Nuclear Information System (INIS)

    Sulfur polymer cement (SPC) is a thermoplastic polymer consisting of 95 wt% elemental sulfur and 5 wt% organic modifiers to enhance long-term durability. SPC was originally developed by the U.S. Bureau of Mines as an alternative to hydraulic cement for construction applications. Previous attempts to use elemental sulfur as a construction material in the chemical industry failed due to premature degradation. These failures were caused by the internal stresses that result from changes in crystalline structure upon cooling of the material. By reacting elemental sulfur with organic polymers, the Bureau of Mines developed a product that successfully suppresses the solid phase transition and significantly improves the stability of the product. SPC, originally named modified sulfur cement, is produced from readily available, inexpensive waste sulfur derived from desulfurization of both flue gases and petroleum. The commercial production of SPC is licensed in the United States by Martin Resources (Odessa, Texas) and is marketed under the trade name Chement 2000. It is sold in granular form and is relatively inexpensive ((approx)$0.10 to 0.12/lb). Application of SPC for the treatment of radioactive, hazardous, and mixed wastes was initially developed and patented by Brookhaven National Laboratory (BNL) in the mid-1980s (Kalb and Colombo, 1985; Colombo et al., 1997). The process was subsequently investigated by the Commission of the European Communities (Van Dalen and Rijpkema, 1989), Idaho National Engineering Laboratory (Darnell, 1991), and Oak Ridge National Laboratory (Mattus and Mattus, 1994). SPC has been used primarily in microencapsulation applications but can also be used for macroencapsulation of waste. SPC microencapsulation has been demonstrated to be an effective treatment for a wide variety of wastes, including incinerator hearth and fly ash; aqueous concentrates such as sulfates, borates, and chlorides; blowdown solutions; soils; and sludges. It is not

  10. Conducting Polymer Based Nanobiosensors

    Directory of Open Access Journals (Sweden)

    Chul Soon Park

    2016-06-01

    Full Text Available In recent years, conducting polymer (CP nanomaterials have been used in a variety of fields, such as in energy, environmental, and biomedical applications, owing to their outstanding chemical and physical properties compared to conventional metal materials. In particular, nanobiosensors based on CP nanomaterials exhibit excellent performance sensing target molecules. The performance of CP nanobiosensors varies based on their size, shape, conductivity, and morphology, among other characteristics. Therefore, in this review, we provide an overview of the techniques commonly used to fabricate novel CP nanomaterials and their biosensor applications, including aptasensors, field-effect transistor (FET biosensors, human sense mimicking biosensors, and immunoassays. We also discuss prospects for state-of-the-art nanobiosensors using CP nanomaterials by focusing on strategies to overcome the current limitations.

  11. Self-healing polymers

    Science.gov (United States)

    Klein, Daniel J. (Inventor)

    2011-01-01

    A three dimensional structure fabricated from a self-healing polymeric material, comprising poly(ester amides) obtained from ethylene glycol, azelaic acid and 1,1-aminoundecanoic acid, wherein polymeric material has a melt index above 2.5 g/10 min. as determined by ASTM D1238 at 190.degree. C. and 2.16kg, impact resistance and ductility sufficient to resist cracking and brittle fracture upon impact by a 9 mm bullet fired at a temperature of about 29.degree. C. at subsonic speed in a range from about 800 feet/sec to about 1000 feet/sec. It has been determined that the important factors necessary for self-healing behavior of polymers include sufficient impact strength, control of the degree of crystallinity, low melting point and the ability to instantly melt at impacted area.

  12. Polymers in Curved Boxes

    CERN Document Server

    Yaman, K; Solis, F J; Witten, T A

    1996-01-01

    We apply results derived in other contexts for the spectrum of the Laplace operator in curved geometries to the study of an ideal polymer chain confined to a spherical annulus in arbitrary space dimension D and conclude that the free energy compared to its value for an uncurved box of the same thickness and volume, is lower when $D < 3$, stays the same when $D = 3$, and is higher when lowers the effective bending elasticity of the walls, and might induce spontaneous symmetry breaking, i.e. bending. (Actually, the above mentioned results show that {\\em {any}} shell in $D = 3$ induces this effect, except for a spherical shell). We compute the contribution of this effect to the bending rigidities in the Helfrich free energy expression.

  13. Polymer Parametrised Field Theory

    CERN Document Server

    Laddha, Alok

    2008-01-01

    Free scalar field theory on 2 dimensional flat spacetime, cast in diffeomorphism invariant guise by treating the inertial coordinates of the spacetime as dynamical variables, is quantized using LQG type `polymer' representations for the matter field and the inertial variables. The quantum constraints are solved via group averaging techniques and, analogous to the case of spatial geometry in LQG, the smooth (flat) spacetime geometry is replaced by a discrete quantum structure. An overcomplete set of Dirac observables, consisting of (a) (exponentials of) the standard free scalar field creation- annihilation modes and (b) canonical transformations corresponding to conformal isometries, are represented as operators on the physical Hilbert space. None of these constructions suffer from any of the `triangulation' dependent choices which arise in treatments of LQG. In contrast to the standard Fock quantization, the non- Fock nature of the representation ensures that the algebra of conformal isometries as well as tha...

  14. Polymer matrix and graphite fiber interface study

    Science.gov (United States)

    Adams, D. F.; Zimmerman, R. S.; Odom, E. M.

    1985-01-01

    Hercules AS4 graphite fiber, unsized, or with EPON 828, PVA, or polysulfone sizing, was combined with three different polymer matrices. These included Hercules 3501-6 epoxy, Hercules 4001 bismaleimide, and Hexcel F155 rubber toughened epoxy. Unidirectional composites in all twelve combinations were fabricated and tested in transverse tension and axial compression. Quasi-isotropic laminates were tested in axial tension and compression, flexure, interlaminar shear, and tensile impact. All tests were conducted at both room temperature, dry and elevated temperature, and wet conditions. Single fiber pullout testing was also performed. Extensive scanning electron microphotographs of fracture surfaces are included, along with photographs of single fiber pullout failures. Analytical/experimental correlations are presented, based on the results of a finite element micromechanics analysis. Correlations between matrix type, fiber sizing, hygrothermal environment, and loading mode are presented. Results indicate that the various composite properties were only moderately influenced by the fiber sizings utilized.

  15. Fragmentation pathways of polymer ions.

    Science.gov (United States)

    Wesdemiotis, Chrys; Solak, Nilüfer; Polce, Michael J; Dabney, David E; Chaicharoen, Kittisak; Katzenmeyer, Bryan C

    2011-01-01

    Tandem mass spectrometry (MS/MS) is increasingly applied to synthetic polymers to characterize chain-end or in-chain substituents, distinguish isobaric and isomeric species, and determine macromolecular connectivities and architectures. For confident structural assignments, the fragmentation mechanisms of polymer ions must be understood, as they provide guidelines on how to deduce the desired information from the fragments observed in MS/MS spectra. This article reviews the fragmentation pathways of synthetic polymer ions that have been energized to decompose via collisionally activated dissociation (CAD), the most widely used activation method in polymer analysis. The compounds discussed encompass polystyrenes, poly(2-vinyl pyridine), polyacrylates, poly(vinyl acetate), aliphatic polyester copolymers, polyethers, and poly(dimethylsiloxane). For a number of these polymers, several substitution patterns and architectures are considered, and questions regarding the ionization agent and internal energy of the dissociating precursor ions are also addressed. Competing and consecutive dissociations are evaluated in terms of the structural insight they provide about the macromolecular structure. The fragmentation pathways of the diverse array of polymer ions examined fall into three categories, viz. (1) charge-directed fragmentations, (2) charge-remote rearrangements, and (3) charge-remote fragmentations via radical intermediates. Charge-remote processes predominate. Depending on the ionizing agent and the functional groups in the polymer, the incipient fragments arising by pathways (1)-(3) may form ion-molecule complexes that survive long enough to permit inter-fragment hydrogen atom, proton, or hydride transfers. PMID:20623599

  16. Nanoscale Study of Polymer Dynamics.

    Science.gov (United States)

    Keshavarz, Masoumeh; Engelkamp, Hans; Xu, Jialiang; Braeken, Els; Otten, Matthijs B J; Uji-I, Hiroshi; Schwartz, Erik; Koepf, Matthieu; Vananroye, Anja; Vermant, Jan; Nolte, Roeland J M; De Schryver, Frans; Maan, Jan C; Hofkens, Johan; Christianen, Peter C M; Rowan, Alan E

    2016-01-26

    The thermal motion of polymer chains in a crowded environment is anisotropic and highly confined. Whereas theoretical and experimental progress has been made, typically only indirect evidence of polymer dynamics is obtained either from scattering or mechanical response. Toward a complete understanding of the complicated polymer dynamics in crowded media such as biological cells, it is of great importance to unravel the role of heterogeneity and molecular individualism. In the present work, we investigate the dynamics of synthetic polymers and the tube-like motion of individual chains using time-resolved fluorescence microscopy. A single fluorescently labeled polymer molecule is observed in a sea of unlabeled polymers, giving access to not only the dynamics of the probe chain itself but also to that of the surrounding network. We demonstrate that it is possible to extract the characteristic time constants and length scales in one experiment, providing a detailed understanding of polymer dynamics at the single chain level. The quantitative agreement with bulk rheology measurements is promising for using local probes to study heterogeneity in complex, crowded systems. PMID:26688072

  17. Non-strinking siloxane polymers

    Science.gov (United States)

    Loy, Douglas A.; Rahimian, Kamyar

    2001-01-01

    Cross-linked polymers formed by ring-opening polymerization of a precursor monomer of the general formula R[CH.sub.2 CH(Si(CH.sub.3).sub.2).sub.2 O].sub.2, where R is a phenyl group or an alkyl group having at least two carbon atoms. A cross-linked polymer is synthesized by mixing the monomer with a co-monomer of the general formula CH.sub.2 CHR.sup.2 (SiMe.sub.2).sub.2 O in the presence of an anionic base to form a cross-linked polymer of recurring units of the general formula R(Me.sub.2 SiOCH.sub.2 CHSiMe.sub.2).sub.2 [CH.sub.2 CHR.sup.2 (SiMe.sub.2).sub.2 O].sub.n, where R.sup.2 is hydrogen, phenyl, ethyl, propyl or butyl. If the precursor monomer is a liquid, the polymer can be directly synthesized in the presence of an anionic base to a cross-linked polymer containing recurring units of the general formula R(Me.sub.2 SiOCH.sub.2 CHSiMe.sub.2).sub.2. The polymers have approximately less than 1% porosity and are thermally stable at temperatures up to approximately 500.degree. C. The conversion to the cross-linked polymer occurs by ring opening polymerization and results in shrinkage of less than approximately 5% by volume.

  18. Monitoring of polymer melt processing

    International Nuclear Information System (INIS)

    The paper reviews the state-of-the-art of in-line and on-line monitoring during polymer melt processing by compounding, extrusion and injection moulding. Different spectroscopic and scattering techniques as well as conductivity and viscosity measurements are reviewed and compared concerning their potential for different process applications. In addition to information on chemical composition and state of the process, the in situ detection of morphology, which is of specific interest for multiphase polymer systems such as polymer composites and polymer blends, is described in detail. For these systems, the product properties strongly depend on the phase or filler morphology created during processing. Examples for optical (UV/vis, NIR) and ultrasonic attenuation spectra recorded during extrusion are given, which were found to be sensitive to the chemical composition as well as to size and degree of dispersion of micro or nanofillers in the polymer matrix. By small-angle light scattering experiments, process-induced structures were detected in blends of incompatible polymers during compounding. Using conductivity measurements during extrusion, the influence of processing conditions on the electrical conductivity of polymer melts with conductive fillers (carbon black or carbon nanotubes) was monitored. (topical review)

  19. Elastic Behavior of Polymer Chains

    Institute of Scientific and Technical Information of China (English)

    Teng Lu; Tao Chen; Hao-jun Liang

    2008-01-01

    The elastic behavior of the polymer chain was investigated in a three-dimensional off-lattice model. We sample more than 109 conformations of each kind of polymer chain by using a Monte Carlo algorithm, then analyze them with the non-Gaussian theory of rubberlike elasticity, and end with a statistical study. Through observing the effect of the chain flexibility and the stretching ratio on the mean-square end-to-end distance,the average energy, the average Helmholtz free energy, the elastic force, the contribution of energy to the elastic force, and the entropy contribution to elastic force of the polymer chain, we find that a rigid polymer chain is much easier to stretch than a flexible polymer chain. Also, a rigid polymer chain will become difficult to stretch only at a quite high stretching ratio because of the effect of the entropy contribution.These results of our simulation calculation may explain some of the macroscopic phenomena of polymer and biomacromolecular elasticity.

  20. Combination Light

    Science.gov (United States)

    1990-01-01

    The Rayovac TANDEM is an advanced technology combination work light and general purpose flashlight that incorporates several NASA technologies. The TANDEM functions as two lights in one. It features a long range spotlight and wide angle floodlight; simple one-hand electrical switching changes the beam from spot to flood. TANDEM developers made particular use of NASA's extensive research in ergonomics in the TANDEM's angled handle, convenient shape and different orientations. The shatterproof, water resistant plastic casing also draws on NASA technology, as does the shape and beam distance of the square diffused flood. TANDEM's heavy duty magnet that permits the light to be affixed to any metal object borrows from NASA research on rare earth magnets that combine strong magnetic capability with low cost. Developers used a NASA-developed ultrasonic welding technique in the light's interior.

  1. Coupling the Alkaline-Surfactant-Polymer Technology and The Gelation Technology to Maximize Oil Production

    Energy Technology Data Exchange (ETDEWEB)

    Malcolm Pitts; Jie Qi; Dan Wilson; Phil Dowling; David Stewart; Bill Jones

    2005-12-01

    Performance and produced polymer evaluation of four alkaline-surfactant-polymer projects concluded that only one of the projects could have benefited from combining the alkaline-surfactant-polymer and gelation technologies. Cambridge, the 1993 Daqing, Mellott Ranch, and the Wardlaw alkaline-surfacant-polymer floods were studied. An initial gel treatment followed by an alkaline-surfactant-polymer flood in the Wardlaw field would have been a benefit due to reduction of fracture flow. Numerical simulation demonstrated that reducing the permeability of a high permeability zone of a reservoir with gel improved both waterflood and alkaline-surfactant-polymer flood oil recovery. A Minnelusa reservoir with both A and B sand production was simulated. A and B sands are separated by a shale layer. A sand and B sand waterflood oil recovery was improved by 196,000 bbls or 3.3% OOIP when a gel was placed in the B sand. Alkaline-surfactant-polymer flood oil recovery improvement over a waterflood was 392,000 bbls or 6.5% OOIP. Placing a gel into the B sand prior to an alkaline-surfactant-polymer flood resulted in 989,000 bbl or 16.4% OOIP more oil than only water injection. A sand and B sand alkaline-surfactant-polymer flood oil recovery was improved by 596,000 bbls or 9.9% OOIP when a gel was placed in the B sand.

  2. Polymer therapeutics-prospects for 21st century: the end of the beginning.

    Science.gov (United States)

    Duncan, Ruth; Vicent, María J

    2013-01-01

    The term "polymer therapeutics" was coined to describe polymeric drugs, polymer conjugates of proteins, drugs and aptamers, together with those block copolymer micelles and multicomponent non-viral vectors which contain covalent linkages. These often complex, multicomponent constructs are actually "drugs" and "macromolecular prodrugs" in contrast to drug delivery systems that simply entrap (non-covalently) therapeutic agents. They have also been described as nanomedicines. First polymer-protein conjugates entered routine clinical use in 1990 and a growing number of polymeric drugs/sequestrants and PEGylated proteins/aptamers have since come into the market. Valuable lessons have been learnt over >3 decades of clinical development, especially in relation to critical product attributes governing safety and efficacy, the validated methods needed for product characterisation. Not least there has been improved understanding of polymer therapeutic-specific biomarkers that will in future enable improved selection of patients for therapy. Advances in synthetic polymer chemistry (including control of 3D architecture), the move towards greater use of biodegradable polymers, polymers delivering combination therapy, increased understanding of polymer therapeutic critical product attributes to guide pharmaceutical development, and advances in understanding of endocytosis and intracellular trafficking pathways in health and disease are opening new opportunities for design and clinical use of polymer-based therapeutics in the decades to come.

  3. Multi-Stimuli-Responsive Polymer Materials: Particles, Films, and Bulk Gels.

    Science.gov (United States)

    Cao, Zi-Quan; Wang, Guo-Jie

    2016-06-01

    Stimuli-responsive polymers have received tremendous attention from scientists and engineers for several decades due to the wide applications of these smart materials in biotechnology and nanotechnology. Driven by the complex functions of living systems, multi-stimuli-responsive polymer materials have been designed and developed in recent years. Compared with conventional single- or dual-stimuli-based polymer materials, multi-stimuli-responsive polymer materials would be more intriguing since more functions and finer modulations can be achieved through more parameters. This critical review highlights the recent advances in this area and focuses on three types of multi-stimuli-responsive polymer materials, namely, multi-stimuli-responsive particles (micelles, micro/nanogels, vesicles, and hybrid particles), multi-stimuli-responsive films (polymer brushes, layer-by-layer polymer films, and porous membranes), and multi-stimuli-responsive bulk gels (hydrogels, organogels, and metallogels) from recent publications. Various stimuli, such as light, temperature, pH, reduction/oxidation, enzymes, ions, glucose, ultrasound, magnetic fields, mechanical stress, solvent, voltage, and electrochemistry, have been combined to switch the functions of polymers. The polymer design, preparation, and function of multi-stimuli-responsive particles, films, and bulk gels are comprehensively discussed here. PMID:27153184

  4. Multi-Stimuli-Responsive Polymer Materials: Particles, Films, and Bulk Gels.

    Science.gov (United States)

    Cao, Zi-Quan; Wang, Guo-Jie

    2016-06-01

    Stimuli-responsive polymers have received tremendous attention from scientists and engineers for several decades due to the wide applications of these smart materials in biotechnology and nanotechnology. Driven by the complex functions of living systems, multi-stimuli-responsive polymer materials have been designed and developed in recent years. Compared with conventional single- or dual-stimuli-based polymer materials, multi-stimuli-responsive polymer materials would be more intriguing since more functions and finer modulations can be achieved through more parameters. This critical review highlights the recent advances in this area and focuses on three types of multi-stimuli-responsive polymer materials, namely, multi-stimuli-responsive particles (micelles, micro/nanogels, vesicles, and hybrid particles), multi-stimuli-responsive films (polymer brushes, layer-by-layer polymer films, and porous membranes), and multi-stimuli-responsive bulk gels (hydrogels, organogels, and metallogels) from recent publications. Various stimuli, such as light, temperature, pH, reduction/oxidation, enzymes, ions, glucose, ultrasound, magnetic fields, mechanical stress, solvent, voltage, and electrochemistry, have been combined to switch the functions of polymers. The polymer design, preparation, and function of multi-stimuli-responsive particles, films, and bulk gels are comprehensively discussed here.

  5. Porous polymer electrolytes with high ionic conductivity and good mechanical property for rechargeable batteries

    Science.gov (United States)

    Liang, Bo; Jiang, Qingbai; Tang, Siqi; Li, Shengliang; Chen, Xu

    2016-03-01

    Porous polymer electrolytes (PPEs) are attractive for developing lithium-ion batteries because of the combined advantages of liquid and solid polymer electrolytes. In the present study, a new porous polymer membrane doped with phytic acid (PA) is prepared, which is used as a crosslinker in polymer electrolyte matrix and can also plasticize porous polymer electrolyte membranes, changing them into soft tough flexible materials. A PEO-PMMA-LiClO4-x wt.% PA (x = weight of PA/weight of polymer, PEO: poly(ethylene oxide); PMMA: poly(methyl methacrylate)) polymer membrane is prepared by a simple evaporation method. The effects of the ratio of PA to PEO-PMMA on the properties of the porous membrane, including morphology, porous structure, and mechanical property, are systematically studied. PA improves the porous structure and mechanical properties of polymer membrane. The maximum tensile strength and elongation of the porous polymer membranes are 20.71 MPa and 45.7% at 15 wt.% PA, respectively. Moreover, the PPEs with 15 wt.% PA has a conductivity of 1.59 × 10-5 S/cm at 20 °C, a good electrochemical window (>5 V), and a low interfacial resistance. The results demonstrate the compatibility of the mechanical properties and conductivity of the PPEs, indicating that PPEs have good application prospects for lithium-ion batteries.

  6. Carbon nanotube and conducting polymer composites for supercapacitors

    Institute of Scientific and Technical Information of China (English)

    Chuang Peng; Shengwen Zhang; Daniel Jewell; George Z. Chen

    2008-01-01

    Composites of carbon nanotubes and conducting polymers can be prepared via chemical synthesis, electrochemical deposition on pre-formed carbon nanotube electrodes, or by electrochemical co-deposition. The composites combine the large pseudocapacitance of the conducting polymers with the fast charging/discharging double-layer capacitance and excellent mechanical properties of the carbon nanotubes. The electrochemically co-deposited composites are the most homogeneous and show an unusual interaction between thepolymer and nanotubes, giving rise to a strengthened electron delocalisation and conjugation along the polymer chains. As a result they exhibit excellent electrochemical charge storage properties and fast charge/discharge switching, making them promising electrode mate-rials for high power supercapacitors.

  7. Quantitative microstructure analysis of polymer-modified mortars.

    Science.gov (United States)

    Jenni, A; Herwegh, M; Zurbriggen, R; Aberle, T; Holzer, L

    2003-11-01

    Digital light, fluorescence and electron microscopy in combination with wavelength-dispersive spectroscopy were used to visualize individual polymers, air voids, cement phases and filler minerals in a polymer-modified cementitious tile adhesive. In order to investigate the evolution and processes involved in formation of the mortar microstructure, quantifications of the phase distribution in the mortar were performed including phase-specific imaging and digital image analysis. The required sample preparation techniques and imaging related topics are discussed. As a form of case study, the different techniques were applied to obtain a quantitative characterization of a specific mortar mixture. The results indicate that the mortar fractionates during different stages ranging from the early fresh mortar until the final hardened mortar stage. This induces process-dependent enrichments of the phases at specific locations in the mortar. The approach presented provides important information for a comprehensive understanding of the functionality of polymer-modified mortars.

  8. Thermal analysis of cement pastes with superabsorbent polymers

    DEFF Research Database (Denmark)

    Esteves, Luis Pedro; Jensen, Ole Mejlhede; Lukosiute, Irena;

    2013-01-01

    Thermal analysis of cement systems is very helpful in the understanding of many different properties of cementitious compounds, both for the original reacting compounds, and also for the resulting hydration products. Superabsorbent polymers can be added to cement systems with many different reasons......, so it is relevant that fundamental knowledge of this new compound on the development of hydration is well understood [1-3]. This paper reports research on thermal analysis of cement pastes with superabsorbent polymers. We have studied several parameters: the concentration of SAP in the system...... and understanding of cementitious materials when internal curing is active. [1] Luís P. Esteves, On the hydration of water-entrained cement–silica systems: Combined SEM, XRD and thermal analysis in cement pastes, Thermochimica Acta, 2011, vol. 518: pp. 27–35. [2] Luís P. Esteves, Superabsorbent Polymers...

  9. Polymer grouts for plugging lost circulation in geothermal wells.

    Energy Technology Data Exchange (ETDEWEB)

    Galbreath, D. (Green Mountain International, Waynesvile, NC); Mansure, Arthur James; Bauer, Stephen J.

    2004-12-01

    We have concluded a laboratory study to evaluate the survival potential of polymeric materials used for lost circulation plugs in geothermal wells. We learned early in the study that these materials were susceptible to hydrolysis. Through a systematic program in which many potential chemical combinations were evaluated, polymers were developed which tolerated hydrolysis for eight weeks at 500 F. The polymers also met material, handling, cost, and emplacement criteria. This screening process identified the most promising materials. A benefit of this work is that the components of the polymers developed can be mixed at the surface and pumped downhole through a single hose. Further strength testing is required to determine precisely the maximum temperature at which extrusion through fractures or voids causes failure of the lost circulation plug.

  10. Polymer amide in the Allende and Murchison meteorites

    Science.gov (United States)

    McGeoch, Julie E. M.; McGeoch, Malcolm W.

    2015-11-01

    It has been proposed that exothermic gas phase polymerization of amino acids can occur in the conditions of a warm dense molecular cloud to form hydrophobic polymer amide (HPA) (McGeoch and McGeoch 2014). In a search for evidence of this presolar chemistry Allende and Murchison meteorites and a volcano control were diamond burr-etched and Folch extracted for potential HPA yielding 85 unique peaks in the meteorite samples via matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI TOF/MS). The amino acids after acid hydrolysis in Allende were below the level of detection but many of the Allende peaks via the more sensitive MALDI/TOF analysis could be fitted to a polymer combination of glycine, alanine, and alpha-hydroxyglycine with high statistical significance. A similar significant fit using these three amino acids could not be applied to the Murchison data indicating more complex polymer chemistry.

  11. Electrically conductive, optically transparent polymer/carbon nanotube composites

    Science.gov (United States)

    Connell, John W. (Inventor); Smith, Jr., Joseph G. (Inventor); Harrison, Joycelyn S. (Inventor); Park, Cheol (Inventor); Watson, Kent A. (Inventor); Ounaies, Zoubeida (Inventor)

    2011-01-01

    The present invention is directed to the effective dispersion of carbon nanotubes (CNTs) into polymer matrices. The nanocomposites are prepared using polymer matrices and exhibit a unique combination of properties, most notably, high retention of optical transparency in the visible range (i.e., 400-800 nm), electrical conductivity, and high thermal stability. By appropriate selection of the matrix resin, additional properties such as vacuum ultraviolet radiation resistance, atomic oxygen resistance, high glass transition (T.sub.g) temperatures, and excellent toughness can be attained. The resulting nanocomposites can be used to fabricate or formulate a variety of articles such as coatings on a variety of substrates, films, foams, fibers, threads, adhesives and fiber coated prepreg. The properties of the nanocomposites can be adjusted by selection of the polymer matrix and CNT to fabricate articles that possess high optical transparency and antistatic behavior.

  12. Colloidal lithography for fabricating patterned polymer-brush microstructures

    Directory of Open Access Journals (Sweden)

    Tao Chen

    2012-05-01

    Full Text Available We exploit a series of robust, but simple and convenient colloidal lithography (CL approaches, using a microsphere array as a mask or as a guiding template, and combine this with surface-initiated atom-transfer radical polymerization (SI-ATRP to fabricate patterned polymer-brush microstructures. The advantages of the CL technique over other lithographic approaches for the fabrication of patterned polymer brushes are (i that it can be carried out with commercially available colloidal particles at a relatively low cost, (ii that no complex equipment is required to create the patterned templates with micro- and nanoscale features, and (iii that polymer brush features are controlled simply by changing the size or chemical functionality of the microspheres or the substrate.

  13. Physical properties of polymers handbook

    CERN Document Server

    2007-01-01

    This book offers concise information on the properties of polymeric materials, particularly those most relevant to physical chemistry and chemical physics. Extensive updates and revisions to each chapter include eleven new chapters on novel polymeric structures, reinforcing phases in polymers, and experiments on single polymer chains. The study of complex materials is highly interdisciplinary, and new findings are scattered among a large selection of scientific and engineering journals. This book brings together data from experts in the different disciplines contributing to the rapidly growing area of polymers and complex materials.

  14. Multilayer Electroactive Polymer Composite Material

    Science.gov (United States)

    Ounaies, Zoubeida (Inventor); Park, Cheol (Inventor); Harrison, Joycelyn S. (Inventor); Holloway, Nancy M. (Inventor); Draughon, Gregory K. (Inventor)

    2011-01-01

    An electroactive material comprises multiple layers of electroactive composite with each layer having unique dielectric, electrical and mechanical properties that define an electromechanical operation thereof when affected by an external stimulus. For example, each layer can be (i) a 2-phase composite made from a polymer with polarizable moieties and an effective amount of carbon nanotubes incorporated in the polymer for a predetermined electromechanical operation, or (ii) a 3-phase composite having the elements of the 2-phase composite and further including a third component of micro-sized to nano-sized particles of an electroactive ceramic incorporated in the polymer matrix.

  15. Statistical properties of curved polymer

    Indian Academy of Sciences (India)

    Surya Kanta Ghosh; Anirban Sain

    2008-08-01

    Intrinsic curvature of biopolymers is emerging as an essential feature in various biological phenomena. Examples of polymers with intrinsic curvature are microtubule in eukaryotic cells or FtsZ filaments in prokaryotic cells. We consider the general model for polymers with intrinsic curvature. We aim to study both equilibrium and dynamic properties of such polymers. Here we report preliminary results on the equilibrium distribution function $P({\\mathbf{R}})$ of the end-to-end distance ${\\mathbf{R}}$. We employ transfer matrix method for this study.

  16. Physics of photorefraction in polymers

    CERN Document Server

    West, Dave

    2004-01-01

    Photorefractive polymer composites are an unusually sensitive class of photopolymers. Physics of Photorefraction in Polymers describes our current understanding of the physical processes that produce a photorefractive effect in key composite materials. Topics as diverse as charge generation, dispersive charge transport, charge compensation and trapping, molecular diffusion, organic composite structure, and nonlinear optical wave coupling are all developed from a physical perspective. Emphasis is placed on explaining how these physical processes lead to observable properties of the polymers, and the authors discuss various applications, including holographic archiving.

  17. Metal-containing conducting polymers

    Energy Technology Data Exchange (ETDEWEB)

    Higgins, S. (Dept. of Chemistry, Univ. of St. Andrews, Fife (United Kingdom)); Crayston, J.A. (Dept. of Chemistry, Univ. of St. Andrews, Fife (United Kingdom))

    1993-03-22

    Poly-(2,6-di-(2-thienyl) pyridine) was investigated for its ability to complex to metals via the pyridine group. Ag[sup +], Cu[sup 2+] and Pd[sup 2+] were reducible in MeCN at the polymer coated electrode after it had been activated by cathodic potentials. The polymer was insulating in aqueous media but in MeCN the cation Ru[sub 3]O(OAc)[sub 6](py)[sub 2](MeOH)[sup +], py=pyridine, was adsorbed onto the polymer as a monolayer. (orig.)

  18. Bioderadable Polymers in Food Packaging

    Directory of Open Access Journals (Sweden)

    P.A.Pawar

    2013-01-01

    Full Text Available In recent years, there has been a marked increase in the interest in use of biodegradable materials in packaging. The principal function of packaging is protection and preservation of food from external contamination. This function involves retardation of deterioration, extension of shelf life, and maintenance of quality and safety of packaged food. Biodegradable polymers are the one which fulfill all these functions without causing any threat to the environment. The belief is that biodegradable polymer materials will reduce the need for synthetic polymer production (thus reducing pollution at a low cost, thereby producing a positive effect both environmentally and economically.

  19. Thermoresponsive Polymers for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Theoni K. Georgiou

    2011-08-01

    Full Text Available Thermoresponsive polymers are a class of “smart” materials that have the ability to respond to a change in temperature; a property that makes them useful materials in a wide range of applications and consequently attracts much scientific interest. This review focuses mainly on the studies published over the last 10 years on the synthesis and use of thermoresponsive polymers for biomedical applications including drug delivery, tissue engineering and gene delivery. A summary of the main applications is given following the different studies on thermoresponsive polymers which are categorized based on their 3-dimensional structure; hydrogels, interpenetrating networks, micelles, crosslinked micelles, polymersomes, films and particles.

  20. Wetting of brushes by polymer melts

    NARCIS (Netherlands)

    Maas, J.

    2001-01-01

    The scientific and practical importance of thin polymer films is evident and in many applications polymer films are required. Hence, studying properties of polymer films is relevant. Adsorption of polymer at liquid/solid interfaces can stabilise particles in a matrix. Homopolymers are often used for

  1. Carbon dioxide foaming of glassy polymers

    NARCIS (Netherlands)

    Wessling, M.; Borneman, Z.; Boomgaard, van den Th.; Smolders, C.A.

    1994-01-01

    The mechanism of foaming a glassy polymer using sorbed carbon dioxide is studied in detail. A glassy polymer supersaturated with nitrogen forms a microcellular foam, if the polymer is quickly heated above its glass transition temperature. A glassy polymer supersaturated with CO2 forms this foam-like

  2. Migration and sensory evaluation of irradiated polymers

    NARCIS (Netherlands)

    Stoffers, N.H.; Linssen, J.P.H.; Franz, R.; Welle, F.

    2004-01-01

    The effects on ionising irradiation on polymer additives, monomers and polymers themselves have been investigated. Changes of initial concentrations of certain additives and monomers, a change in their specific migration as well as sensory changes of the polymers were examined. Polymer stabilizers s

  3. Carbon nanotube-polymer composite actuators

    Science.gov (United States)

    Gennett, Thomas; Raffaelle, Ryne P.; Landi, Brian J.; Heben, Michael J.

    2008-04-22

    The present invention discloses a carbon nanotube (SWNT)-polymer composite actuator and method to make such actuator. A series of uniform composites was prepared by dispersing purified single wall nanotubes with varying weight percents into a polymer matrix, followed by solution casting. The resulting nanotube-polymer composite was then successfully used to form a nanotube polymer actuator.

  4. The Workshop on Conductive Polymers: Final Report

    Science.gov (United States)

    1985-10-01

    Reports are made by groups on: polyacetylene, polyphenylene, polyaniline, and related systems; molecular, crystallographic, and defect structures in conducting polymers; heterocyclic polymers; synthesis of new and improved conducting polymers; future applications possibilities for conducting polymers; and challenges for improved understanding of properties. (DLC)

  5. Method for bonding a thermoplastic polymer to a thermosetting polymer component

    NARCIS (Netherlands)

    Van Tooren, M.J.L.

    2012-01-01

    The invention relates to a method for bonding a thermoplastic polymer to a thermosetting polymer component, the thermoplastic polymer having a melting temperature that exceeds the curing temperature of the thermosetting polymer. The method comprises the steps of providing a cured thermosetting polym

  6. Polymer and Polymer Gel of Liquid Crystalline Semiconductors

    Institute of Scientific and Technical Information of China (English)

    Teppei Shimakawa; Naoki Yoshimoto; Jun-ichi Hanna

    2004-01-01

    It prepared a polymer and polymer gel of a liquid crystalline (LC) semiconductor having a 2-phenylnaphthalene moiety and studied their charge carrier transport properties by the time-of-flight technique. It is found that polyacrylate having the mesogenic core moiety of 2-phenylnaphtalene (PNP-acrylate) exhibited a comparable mobility of 10-4cm2/Vs in smectic A phase to those in smectic A (SmA) phase of small molecular liquid crystals with the same core moiety, e.g., 6-(4'-octylphenyl)- 2-dodecyloxynaphthalene (8-PNP-O12), and an enhanced mobility up to 10-3cm2/Vs in the LC-glassy phase at room temperature, when mixed with a small amount of 8-PNP-O12. On the other hand, the polymer gel consisting of 20 wt %-hexamethylenediacrylate (HDA)-based cross-linked polymer and 8-PNP-O12 exhibited no degraded mobility when cross-linked at the mesophase. These results indicate that the polymer and polymer composite of liquid crystalline semiconductors provide us with an easy way to realize a quality organic semiconductor thin film for the immediate device applications.

  7. The Role of Polymer Fractionation in Energetic Losses and Charge Carrier Lifetimes of Polymer: Fullerene Solar Cells

    KAUST Repository

    Baran, Derya

    2015-08-10

    Non-radiative recombination reduces the open-circuit voltage relative to its theoretical limit and leads to reduced luminescence emission at a given excitation. Therefore it is possible to correlate changes in luminescence emission with changes in open-circuit voltage and in the charge carrier lifetime. Here we use luminescence studies combined with transient photovoltage and differential charging analyses to study the effect of polymer fractionation in indacenoedithiophene-co-benzothiadiazole (IDTBT):fullerene solar cells. In this system, polymer fractionation increases electroluminescence and reduces non-radiative recombination. High molecular weight and fractionated IDTBT polymers exhibit higher carrier lifetime-mobility product compared to their non-fractionated analogues, resulting in improved solar cell performance.

  8. 3D Viscoelastic Finite Element Modelling of Polymer Flow in the Fiber Drawing Process for Microstructured Polymer Optical Fiber Fabrication

    DEFF Research Database (Denmark)

    Fasano, Andrea; Rasmussen, Henrik K.; Marín, J. M. R.

    2015-01-01

    The process of drawing an optical fiber from a polymer preform is still not completely understood,although it represents one of the most critical steps in the process chain for the fabrication of microstructuredpolymer optical fibers (mPOFs). Here we present a new approach for the numerical...... modelling of the fiber drawingprocess using a fully three-dimensional and time-dependent finite element method, giving significant insightinto this widely spread mPOF production technique. Our computational predictions are physically based on theviscoelastic fluid dynamics of polymers. Until now...... the numerical modelling of mPOF drawing has mainly beenbased on principles, such as generalized Newtonian fluid dynamics, which are not able to cope with the elasticcomponent in polymer flow. In the present work, we employ the K-BKZ constitutive equation, a non-linearsingle-integral model that combines both...

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

    Science.gov (United States)

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

    2015-01-01

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

  10. Applications of polymers for biomolecule immobilization in electrochemical biosensors

    International Nuclear Information System (INIS)

    Polymers are becoming inseparable from biomolecule immobilization strategies and biosensor platforms. Their original role as electrical insulators has been progressively substituted by their electrical conductive abilities, which opens a new and broad scope of applications. In addition, recent advances in diagnostic chips and microfluidic systems, together with the requirements of mass-production technologies, have raised the need to replace glass by polymeric materials, which are more suitable for production through simple manufacturing processes. Conducting polymers (CPs), in particular, are especially amenable for electrochemical biosensor development for providing biomolecule immobilization and for rapid electron transfer. It is expected that the combination of known polymer substrates, but also new transducing and biocompatible interfaces, with nanobiotechnological structures, like nanoparticles, carbon nanotubes (CNTs) and nanoengineered 'smart' polymers, may generate composites with new and interesting properties, providing higher sensitivity and stability of the immobilized molecules, thus constituting the basis for new and improved analytical devices for biomedical and other applications. This review covers the state-of-the-art and main novelties about the use of polymers for immobilization of biomolecules in electrochemical biosensor platforms

  11. Polymer nanofibrous structures: Fabrication, biofunctionalization, and cell interactions.

    Science.gov (United States)

    Beachley, Vince; Wen, Xuejun

    2010-07-01

    Extracellular matrix fibers (ECM) such as collagen, elastin, and keratin provide biological and physical support for cell attachment, proliferation, migration, differentiation and ultimately cell fate. Therefore, ECM fibers are an important component in tissue and organ development and regeneration. Meanwhile, polymer nanofibers could play the same critical role in tissue regeneration process. Fibrous structures can be fabricated from a variety of materials and methods with diameters ranging throughout the size scale where cells can sense individual fibers (several nanometers to several microns). Polymer nanofiber scaffolds can be designed in a way that predictably modulates a variety of important cell behaviors towards a desired overall function. The nanofibrous topography itself, independent of the fiber material, has demonstrated the potential to modulate cell behaviors desirable in tissue engineering such as: unidirectional alignment; increased viability, attachment, and ECM production; guided migration; and controlled differentiation. The versatility of polymer nanofibers for functionalization with biomolecules opens the door to vast opportunities for the design of tissue engineering scaffolds with even greater control over cell incorporation and function. Despite the promise of polymer nanofibers as tissue engineering scaffolds there have been few clinically relevant successes because no single fabrication technique currently combines control over structural arrangement, material composition, and biofunctionalization, while maintaining reasonable cost and yield. Promising strategies are currently being investigated to allow for the fabrication of optimal polymer nanofiber tissue engineering scaffolds with the goal of treating damaged and degenerated tissues in a clinical setting.

  12. Mineralized polymer composites as biogenic bone substitute material

    Science.gov (United States)

    Shah, Rushita; Saha, Nabanita; Kitano, Takeshi; Saha, Petr

    2015-05-01

    Mineralized polymer composites (MPC) are recognized as potential fillers of bone defects. Though bioceramics exhibits quite a good bone-bonding and vascularization, it is considered to be too stiff and brittle for using alone. Thus, the use of polymer scaffold instead of bioceramics has several advantages including combining the osteoconductivity and bone-bonding potential of the inorganic phase with the porosity and interconnectivity of the three-dimensional construction. Aiming the advantages of ceramic-polymer composite scaffolds, the calcium carbonate (CaCO3) based biomineralized scaffold was prepared, where the PVP-CMC hydrogel was used as an extracellular matrix. This paper is reported about the morphology, swelling trend (in physiological solution) and viscoelastic behavior of (90 min mineralized) MPC. The dry MPC are off-white, coarse in texture, comparatively less flexible than the original PVP-CMC based hydrogel film, and the deposition of granular structures on the surface of the hydrogel film confirms about the development of biomineralized scaffold/polymer composites. Irrespective of thickness, the dry MPC shows higher values of swelling ratio within 30 min, which varies between 200-250 approximately. The dynamic viscoelastic nature of freshly prepared MPC was investigated applying 1% and 10% strain. At higher strain the viscoelastic moduli (G' and G") show significant change, and the nature of MPC turns from elastic to viscous. Based on the observed basic properties, the MPC (calcite based polymer composites) can be recommended for the treatment of adyanamic bone disorder.

  13. Approaches for Making High Performance Polymer Materials from Commodity Polymers

    Institute of Scientific and Technical Information of China (English)

    Xu Xi

    2004-01-01

    A brief surrey of ongoing research work done for improving and enhancing the properties of commodity polymers by the author and author's colleagues is given in this paper. A series of high performance polymers and polymer nanomaterials were successfully prepared through irradiation and stress-induced reactions of polymers and hydrogen bonding. The methods proposed are viable, easy in operation, clean and efficient.1. The effect of irradiation source (UV light, electron beam, γ -ray and microwave), irradiation dose, irradiation time and atmosphere etc. on molecular structure of polyolefine during irradiation was studied. The basic rules of dominating oxidation, degradation and cross-linking reactions were mastered. Under the controlled conditions, cross-linking reactions are prevented, some oxygen containing groups are introduced on the molecular chain of polyolefine to facilitate the interface compatibility of their blends. A series of high performance polymer materials: u-HDPE/PA6,u-HDPE/CaCO3, u-iPP/STC, γ-HDPE/STC, γ-LLDPE/ATH, e-HDPE, e-LLDPE and m-HDPEfilled system were prepared (u- ultraviolet light irradiated, γ- γ-ray irradiated, e- electron beam irradiated, m- microwave irradiated)2. The effect of ultrasonic irradiation, jet and pan-milling on structure and changes in properties of polymers were studied. Imposition of critical stress on polymer chain can cause the scission of bonds to form macroradicals. The macroradicals formed in this way may recombine or react with monomer or other radicals to form linear, branched or cross-linked polymers or copolymers. About 20 kinds of block/graft copolymers have been synthesized from polymer-polymer or polymer-monomer through ultrasonic irradiation.Through jet-milling, the molecular weight of PVC is decreased somewhat, the intensity of its crystalline absorption bonds becomes indistinct. The processability, the yield strength, strength at break and elongation at break of PVC get increased quite a lot after

  14. Recent advances in photorefractive polymers

    Science.gov (United States)

    Thomas, Jayan; Christenson, C. W.; Lynn, B.; Blanche, P.-A.; Voorakaranam, R.; Norwood, R. A.; Yamamoto, M.; Peyghambarian, N.

    2011-10-01

    Photorefractive composites derived from conducting polymers offer the advantage of dynamically recording holograms without the need for processing of any kind. Thus, they are the material of choice for many cutting edge applications, such as updatable three-dimensional (3D) displays and 3D telepresence. Using photorefractive polymers, 3D images or holograms can be seen with the unassisted eye and are very similar to how humans see the actual environment surrounding them. Absence of a large-area and dynamically updatable holographic recording medium has prevented realization of the concept. The development of a novel nonlinear optical chromophore doped photoconductive polymer composite as the recording medium for a refreshable holographic display is discussed. Further improvements in the polymer composites could bring applications in telemedicine, advertising, updatable 3D maps and entertainment.

  15. SCATTERING FUNCTION OF POLYMER BLENDS

    Institute of Scientific and Technical Information of China (English)

    Lin-ping Ke; Mei-li Guo; De-lu Zhao

    2004-01-01

    For a system of flexible polymer molecules, the concepts of two concentrations, namely the segmental and the molecular concentrations, have been proposed in this paper. The former is equivalent to the volume fraction. The latter can be defined as the number of the gravity centers of macromolecules in a unit volume. The two concentrations should be correlated with each other by the conformational function of the polymer chain and should be discussed in different thermodynamic equations. On the basis of these concepts it has been proved that the Flory-Huggins entropy of mixing should be the result of the mixing "ideal gases of the gravity centers of macromolecules". The general correlation between the free energy of mixing and the scattering function (structural factor) of polymer blends has been studied based on the general fluctuation theory. When the Flory-Huggins free energy of mixing is adopted, the de Gennes scattering function of a polymer blend can be derived.

  16. Deformation of Linked Polymer Coils

    Institute of Scientific and Technical Information of China (English)

    董朝霞; 李明远; 吴肇亮; 林梅钦

    2003-01-01

    Linked polymer solution (LPS) is defined as the solution of linked polymer coils (LPCs) dispersed in water, composed of low concentration partially hydrolyzed polyacrylamide (HPAM) and aluminum citrate (crosslinker). In the work, the conformational changes of LPCs under different conditions were investigated by the methods of membrane filtering under low pressure, dynamic light scattering and core flooding experiments. The results showed that in some conditions the LPCs could be compressed mechanically to 1/158.5 of their original volume because of relatively lower HPAM cross-linking. The hydration property of LPCs was similar to that of normal polymer coils. The deformation of LPCs was more restricted than that of ordinary polymer coils under the flow shear stress or the shift of hydration equilibrium caused in the variation of the electrolyte concentration which is responsible for the effective plugging in the throats of porous media when LPCs are used for deep diverting.

  17. Light-emitting polymer LEDs

    Energy Technology Data Exchange (ETDEWEB)

    Moratti, S.C.; Bradley, D.D.C.; Cervini, R.; Friend, R.H.; Greenham, N.C.; Holmes, A.B. [Univ. of Cambridge (United Kingdom)

    1994-12-31

    Simple light emitting diodes can be constructed using fluorescent organic materials. Conjugated polymers can be used both for charge transport and for light emission. It is considered necessary for maximum device efficiency to balance the rates of electron and hole injection. The authors report the synthesis of a poly(cyanoterephthalylidenene) that was designed to exhibit an increased electron affinity. Electrochemical measurements showed a significant shift in the oxidation and reduction potentials due to the cyano functionality. The use of this polymer in a range of electroluminescent devices is described. Internal quantum efficiencies of up to 4% can be achieved in a bilayer device using stable electrode materials. The route used to synthesize this polymer is amenable to considerable variation in the subunits employed. This allows tuning of both the band-gap and the electron affinity of the resulting polymer.

  18. Polymer electronic devices and materials.

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, William Kent; Baca, Paul Martin; Dirk, Shawn M.; Anderson, G. Ronald; Wheeler, David Roger

    2006-01-01

    Polymer electronic devices and materials have vast potential for future microsystems and could have many advantages over conventional inorganic semiconductor based systems, including ease of manufacturing, cost, weight, flexibility, and the ability to integrate a wide variety of functions on a single platform. Starting materials and substrates are relatively inexpensive and amenable to mass manufacturing methods. This project attempted to plant the seeds for a new core competency in polymer electronics at Sandia National Laboratories. As part of this effort a wide variety of polymer components and devices, ranging from simple resistors to infrared sensitive devices, were fabricated and characterized. Ink jet printing capabilities were established. In addition to promising results on prototype devices the project highlighted the directions where future investments must be made to establish a viable polymer electronics competency.

  19. Conjugated Polymers for Energy Production

    DEFF Research Database (Denmark)

    Livi, Francesco

    This dissertation is aimed at developing materials for flexible, large area, ITO-free polymer solar cells (PSCs) fully printed under ambient conditions. A large screening of conjugated polymers, both novel and well-known materials, has been carried out in order to find suitable candidates...... for scalable PSCs fully printed under ambient conditions [Adv. Energy Mater. 2015, 5, 1402186]. PPDTBT resulted to be the conjugated polymer with the best photovoltaic performance within the 104 synthesized macromolecules. Therefore, further studies have been done on such material. The impact of side chain...... arylation (DAr) and direct arylation polymerization (DArP) have been applied to the preparation of PPDTBT, making this polymer readily available in only 4 synthetic steps and thus easily transferable to a large scale-production setup. DArP avoids organometallic species and therefore is an appealing...

  20. Color Changes Mark Polymer Reactions.

    Science.gov (United States)

    Krieger, James H.

    1980-01-01

    Describes how polydiacetylenes can be used as educational aids. These polymers have conjugated backbones, which cause changes in color when the polydiacetylenes undergo various chemical and physical processes. Diagrams summarize all chemical reactions and their associated color changes. (CS)

  1. Modeling the polymer product maceration

    Science.gov (United States)

    Ahunov, D. N.; Karpova, M. N.

    2014-12-01

    The article contains a view of mass transmission simulation procedure conformably to control of manufacturing method's automation, and also is shown a simulator of polymer product maceration process, and results of developed for this simulator realization program system

  2. Finely divided, irradiated tetrafluorethylene polymers

    International Nuclear Information System (INIS)

    Dry non-sticky fine lubricant powders are made by γ-irradiation of unsintered coagulated dispersion grade tetrafluoroethylene polymers. These powders may also be dispersed in an organic medium for lubricating purposes

  3. Sonochemical Preparation of Polymer Nanocomposites

    Directory of Open Access Journals (Sweden)

    Hyoung Jin Choi

    2009-06-01

    Full Text Available Thisreview covers sonochemical fabrication of polymer nanocomposites. In addition to its application to the synthesis of various polymeric systems, due to its powerful efficiency, sonochemistry has been widely used not only as the assistant of dispersion for nanomaterials such as carbon nanotubes (CNT and organophillic clay, but also as a special initiator to enhance polymerization for fabrication of polymer nanocomposites with CNT and metallic nanoparticles. Recent developments in the preparation of multi-walled carbon nanotube/polymer nanocomposites with polystyrene and PMMA, magnetic particle/CNT composites and polymer/clay nanocomposites along with their physical characteristics and potential engineering applications will be introduced. Physical characterizations include morphological, thermal, and rheological properties under either an applied electric or magnetic field.

  4. Polymer Bose–Einstein condensates

    Energy Technology Data Exchange (ETDEWEB)

    Castellanos, E., E-mail: ecastellanos@fis.cinvestav.mx [Departamento de Física, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, A.P. 14-740, México D.F. 07000 (Mexico); Chacón-Acosta, G., E-mail: gchacon@correo.cua.uam.mx [Departamento de Matemáticas Aplicadas y Sistemas, Universidad Autónoma Metropolitana-Cuajimalpa, Artificios 40, México D.F. 01120 (Mexico)

    2013-05-13

    In this work we analyze a non-interacting one-dimensional polymer Bose–Einstein condensate in a harmonic trap within the semiclassical approximation. We use an effective Hamiltonian coming from the polymer quantization that arises in loop quantum gravity. We calculate the number of particles in order to obtain the critical temperature. The Bose–Einstein functions are replaced by series, whose high order terms are related to powers of the polymer length. It is shown that the condensation temperature presents a shift respect to the standard case, for small values of the polymer scale. In typical experimental conditions, it is possible to establish a bound for λ{sup 2} up to ≲10{sup −16} m{sup 2}. To improve this bound we should decrease the frequency of the trap and also decrease the number of particles.

  5. Polyphosphazine-based polymer materials

    Science.gov (United States)

    Fox, Robert V.; Avci, Recep; Groenewold, Gary S.

    2010-05-25

    Methods of removing contaminant matter from porous materials include applying a polymer material to a contaminated surface, irradiating the contaminated surface to cause redistribution of contaminant matter, and removing at least a portion of the polymer material from the surface. Systems for decontaminating a contaminated structure comprising porous material include a radiation device configured to emit electromagnetic radiation toward a surface of a structure, and at least one spray device configured to apply a capture material onto the surface of the structure. Polymer materials that can be used in such methods and systems include polyphosphazine-based polymer materials having polyphosphazine backbone segments and side chain groups that include selected functional groups. The selected functional groups may include iminos, oximes, carboxylates, sulfonates, .beta.-diketones, phosphine sulfides, phosphates, phosphites, phosphonates, phosphinates, phosphine oxides, monothio phosphinic acids, and dithio phosphinic acids.

  6. Cyclodextrin Inclusion Polymers Forming Hydrogels

    Science.gov (United States)

    Li, Jun

    This chapter reviews the advances in the developments of supramolecular hydrogels based on the polypseudorotaxanes and polyrotaxanes formed by inclusion complexes of cyclodextrins threading onto polymer chains. Both physical and chemical supramolecular hydrogels of many different types are discussed with respect to their preparation, structure, property, and gelation mechanism. A large number of physical supramolecular hydrogels were formed induced by self-assembly of densely packed cyclodextrin rings threaded on polymer or copolymer chains acting as physical crosslinking points. The thermo-reversible and thixotropic properties of these physical supramolecular hydrogels have inspired their applications as injectable drug delivery systems. Chemical supramolecular hydrogels synthesized from polypseudorotaxanes and polyrotaxanes were based on the chemical crosslinking of either the cyclodextrin molecules or the included polymer chains. The chemical supramolecular hydrogels were often made biodegradable through incorporation of hydrolyzable threading polymers, end caps, or crosslinkers, for their potential applications as biomaterials.

  7. Photosensitized oxidation of unsaturated polymers

    Science.gov (United States)

    Golub, M. A.

    1980-01-01

    A review of the photosensitized oxidation of singlet oxygenation of unsaturated hydrocarbon polymers and of their model compounds is presented. The cis and trans forms of 1,4-polyisoprene, 1,4-polybutadiene and 1,2-poly(1,4-hexadiene) are studied, and their microstructural changes which occur on reaction with (IO2) in solution were investigated by infrared, (H-1) and (C-13) NMR spectroscopy. The polymers yielded allylic hydroperoxides with shifted double bonds according to the 'ene' mechanism of simple olefins. It was shown that single oxygenation of unsaturated polymers is similar to their low molecular weight analogs, and that the differences are due to secondary processes affecting the (IO2)-reacted polymers.

  8. Emergent tilt order in Dirac polymer liquids

    OpenAIRE

    Souslov, Anton; Loewe, Benjamin; Goldbart, Paul M.

    2014-01-01

    We study a liquid of zigzagging two-dimensional directed polymers with bending rigidity, i.e., polymers whose conformations follow checkerboard paths. In the continuum limit the statistics of such polymers obey the Dirac equation for particles of imaginary mass. We exploit this observation to investigate a liquid of these polymers via a quantum many-fermion analogy. A self-consistent approximation predicts a phase of tilted order, in which the polymers may develop a preference to zig rather t...

  9. Are Entangled Polymer Melts Different From Solutions?

    OpenAIRE

    Huang, Qian; Mednova, Olga; Rasmussen, Henrik K.; Skov, Anne Ladegaard; Almdal, Kristoffer; Hassager, Ole

    2012-01-01

    The possible existence of a qualitative difference on extensional steady state viscosity between polymer melts and polymer solutions is still an open question. Recent experiments [1-4] showed the extensional viscosity of both polymer melts and solutions decayed as a function of strain rate with an exponent of -0.5. When the strain rate became higher than the order of inverse Rouse time, the polymer solutions showed an upturn [1, 4]. However, in the same regime for polymer melts, the experimen...

  10. Physical Organic Chemistry of Supramolecular Polymers

    Science.gov (United States)

    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

  11. Surface segregation of conformationally asymmetric polymer blends

    OpenAIRE

    Stepanow, Semjon; Fedorenko, Andrei A.

    2005-01-01

    We have generalized the Edwards' method of collective description of dense polymer systems in terms of effective potentials to polymer blends in the presence of a surface. With this method we have studied conformationally asymmetric athermic polymer blends in the presence of a hard wall to the first order in effective potentials. For polymers with the same gyration radius $R_g$ but different statistical segment lengths $l_{A}$ and $l_{B}$ the excess concentration of stiffer polymers at the su...

  12. Study about polymer applications in footwear

    OpenAIRE

    Khan, Majbaur

    2015-01-01

    This thesis was written to study polymer uses in footwear and to define engineered polymers in footwear. How and why polymers are used nowadays in footwear. Though leather is a prime material for footwear but polymers are used for their some properties which are suitable for footwear. It is also significant in this thesis the comparison of leather and polymers as a footwear material. To describe the classification and mechanism of adhesive those are used in this sector is also a very importan...

  13. Polymer-phyllosilicate nanocomposites and their preparation

    Science.gov (United States)

    Chaiko, David J.

    2007-01-09

    Polymer-phyllosilicate nanocomposites that exhibit superior properties compared to the polymer alone, and methods-for producing these polymer-phyllosilicate nanocomposites, are provided. Polymeric surfactant compatabilizers are adsorbed onto the surface of hydrophilic or natural phyllosilicates to facilitate the dispersal and exfoliation of the phyllosilicate in a polymer matrix. Utilizing polymeric glycol based surfactants, polymeric dicarboxylic acids, polymeric diammonium surfactants, and polymeric diamine surfactants as compatabilizers facilitates natural phyllosilicate and hydrophilic organoclay dispersal in a polymer matrix to produce nanocomposites.

  14. Wetting of brushes by polymer melts

    OpenAIRE

    Maas, J

    2001-01-01

    The scientific and practical importance of thin polymer films is evident and in many applications polymer films are required. Hence, studying properties of polymer films is relevant. Adsorption of polymer at liquid/solid interfaces can stabilise particles in a matrix. Homopolymers are often used for steric stabilisation of particles although these polymers can also destabilise the system by bridging. Diblock copolymers with one adsorbing (anchor) block and one non-adsorbing (buoy) block may b...

  15. 树脂膜控释尿素及普通尿素配施对强筋小麦产量、品质和氮肥利用率的影响%Effects of Combined Application of Polymer-coated Controlled Release Urea and Common Urea on Yield, Quality and Fertilizer Nitrogen Use Efficiency of Strong Gluten Wheat

    Institute of Scientific and Technical Information of China (English)

    李敏; 郭熙盛; 叶舒娅; 曹承富; 武际; 黄义德

    2013-01-01

    为给小麦高产优质栽培中控释尿素的合理应用提供理论依据,以控释期90 d的树脂膜控释尿素为材料,通过田间小区试验,研究了树脂膜控释尿素及普通尿素配施对强筋小麦产量、品质及氮肥利用率的影响.结果表明,与普通尿素(PU)全部底施相比,树脂膜控释尿素及普通尿素配施抑制剂处理均能显著提高小麦产量和氮肥利用率,增幅分别达5.6%~12.6%和32.4%~137.3%.与分次施用普通尿素相比,树脂膜控释尿素及普通尿素配施抑制剂处理使籽粒产量增加1.5%~8.2%;等氮量施用树脂膜控释尿素处理显著提高了籽粒蛋白质含量、沉降值及湿面筋含量;等氮量施用树脂膜控释尿素及普通尿素配施抑制剂处理显著提高了氮肥利用率,增幅达13.9%~42.6%.小麦籽粒产量、品质、土壤无机氮与氮肥利用率皆以树脂膜控释尿素70%+普通尿素30%处理最高,其中产量和氮肥利用率与其他施氮处理差异显著.%Using polymer-coated controlled release urea fertilizers (CRU) with releasing period of 90 d as experimental materials, a field experiment was conducted to study the effects of CRU on yield, quality and nitrogen use efficiency of wheat, and to improve wheat production and quality and N utilization. Compared with all urea used as base fertilizer (PU100%), CRU and combined application of common urea with inhibitors significantly increased the grain yield by 5. 6% -12. 6%, and N use efficiency by 32. 4% ~ 137. 3%. Compared with urea used as base and dressing fertilizer (PU60%+ PU40%), CRU and combined application of common urea with inhibitors increased the grain yield by 1. 5%~8. 2%. Application with CRU at equal N content greatly improved protein content, sedimentation volume and wet gluten content. Application with CRU and common urea with inhibitors significantly at equal N content improved N use efficiency by 13. 9%~42. 6%. The grain yield and

  16. β-磷酸三钙复合有机高分子聚合物骨支架材料:制备及应用中的问题%Beta-tricalcium phosphate combined with organic polymer as bone scaffolds:scaffold preparation and application

    Institute of Scientific and Technical Information of China (English)

    叶铄; 甄平

    2014-01-01

    背景:通过研究发现,将β-磷酸三钙与其他高分子化合物复合,可以提高其力学强度和组织相容性,符合临床应用的要求。  目的:评价骨组织工程复合支架的选择和制备方法,并叙述面临的问题。  方法:由第一作者应用计算机检索2002至2014年PubMed数据库、GOOGLE学术数据库、CNKI数据库、万方数据库、维普数据库,中文检索词为“β-磷酸三钙或β-TCP,聚乳酸-羟基乙酸共聚物,聚乳酸,制备,骨组织工程支架”,英文检索词为“β-tricalcium phosphate,PLGA,PLA,scaffold,prepare”。  结果与结论:为了解决骨移植中骨量不足的问题,聚乳酸-羟基乙酸共聚物/聚乳酸复合β-磷酸三钙材料作为骨组织工程支架材料已取得较大的进展,目前可采用微球烧结、纤维黏结、溶剂浇铸/粒子沥滤、乳化/冷冻干燥技术、气体发泡法、相分离技术、快速成型技术和静电纺丝等方法制备复合有机高分子聚合物的支架。聚乳酸-羟基乙酸共聚物/聚乳酸与β-磷酸三钙复合支架可定制,可以通过改进制造技术、工艺等问题,以满足不同的骨组织工程应用需求。%BACKGROUND:Studies have shown that theβ-tricalcium phosphate can be combined with other macromolecular compounds to improve the mechanical strength and histocompatibility, meeting the requirements of clinical application. OBJECTIVE:To evaluate the selection and preparation methods of composite scaffold in bone tissue engineering, and to describe the problems we are facing. METHODS:The first author retrieved PubMed, Google Scholar, CNKI, Wanfang, and VIP databases by computer using the keywords of“β-tricalcium phosphate,β-TCP, PLGA, PLA, scaffold, prepare”in English and Chinese, respectively. RESULTS AND CONCLUSION:β-tricalcium phosphate combined with polylactic acid-glycolic acid/polylactic acid as bone tissue engineering scaffolds

  17. Characterization of Tantalum Polymer Capacitors

    Science.gov (United States)

    Spence, Penelope

    2012-01-01

    Overview Reviewed data Caution must be taken when accelerating test conditions Data not useful to establish an acceleration model Introduction of new failure mechanism skewing results Evidence of Anti-Wear-Out De-doping of polymer Decreased capacitance Increased ESR Not dielectric breakdown Needs further investigation Further investigation into tantalum polymer capacitor technology Promising acceleration model for Manufacturer A Possibility for use in high-reliability space applications with suitable voltage derating.

  18. Thermodynamics of tubelike flexible polymers

    OpenAIRE

    Vogel, T.; Neuhaus, T; Bachmann, M.; Janke, W.

    2009-01-01

    In this work, we discuss the general phase behavior of short tubelike flexible polymers. The geometric thickness constraint is implemented through the concept of the global radius of curvature. We use sophisticated Monte Carlo sampling methods to simulate small bead-stick polymer models with Lennard-Jones interaction among nonbonded monomers. We analyze energetic fluctuations and structural quantities to classify conformational pseudophases. We find that the tube thickness influences the ther...

  19. Nanoporous polymer liquid core waveguides

    DEFF Research Database (Denmark)

    Gopalakrishnan, Nimi; Christiansen, Mads Brøkner; Ndoni, Sokol;

    2010-01-01

    We demonstrate liquid core waveguides defined by UV to enable selective water infiltration in nanoporous polymers, creating an effective refractive index shift Δn=0.13. The mode confinement and propagation loss in these waveguides are presented.......We demonstrate liquid core waveguides defined by UV to enable selective water infiltration in nanoporous polymers, creating an effective refractive index shift Δn=0.13. The mode confinement and propagation loss in these waveguides are presented....

  20. Biocompatible and Bioeliminable Hydrophilic Polymers

    Institute of Scientific and Technical Information of China (English)

    Paolo; FerrutiUniversità

    2007-01-01

    1 Introduction This presentation will report on some recent results obtained in Milan on two polymer families of biomedical interest, namely poly(N-vinyl-2-pyrrolidinone) and polyamidoamines. 2 Results and DiscussionPoly(N-vinyl-2-pyrrolidinone) (PVP) is a well known bioactive and biocompatible polymer. In its soluble form, it is largely used as excipient of oral pharmaceutical formulations, especially for its high water solubilising power.In its crosslinked form, it plays a relevant role as biomateria...

  1. High cation transport polymer electrolyte

    Science.gov (United States)

    Gerald, II, Rex E.; Rathke, Jerome W.; Klingler, Robert J.

    2007-06-05

    A solid state ion conducting electrolyte and a battery incorporating same. The electrolyte includes a polymer matrix with an alkali metal salt dissolved therein, the salt having an anion with a long or branched chain having not less than 5 carbon or silicon atoms therein. The polymer is preferably a polyether and the salt anion is preferably an alkyl or silyl moiety of from 5 to about 150 carbon/silicon atoms.

  2. Heterogeneity in Polymer Thin Films

    OpenAIRE

    Kanaya, Toshiji; Inoue, Rintaro; Nishida, Koji

    2011-01-01

    In the last two decades very extensive studies have been performed on polymer thin films to reveal very interesting but unusual properties. One of the most interesting findings is the decrease in glass transition temperature Tg with film thickness in polystyrene (PS) thin film supported on Si substrate. Another interesting finding is apparent negative thermal expansivity in glassy state for thin films below ∼25 nm. In order to understand the unusual properties of polymer thin films we have st...

  3. Radiation processing of natural polymer

    International Nuclear Information System (INIS)

    Radiation processing of natural polymer has been the subject of interest of countries in this region in the past 5 ∼ 7 years. Although some of the output of the research have been commercialized in particular for the applications in the agriculture and healthcare sectors, the potential applications of radiation processing of natural polymers in the medical sector are yet to be fully understood and developed. (author)

  4. Methods of polymer binder examination

    Directory of Open Access Journals (Sweden)

    M. Holtzer

    2010-10-01

    Full Text Available This article presents selected methods of examining polymer binders (in particular current or promising ones, including spectroscopy, microscopy, nanometry, chromatography and thermal analysis. The table (containing 23 literature references collates and generally characterises over 20 analytical methods from the above groups. In addition, information is presented on research conducted by the Environmental Protection Lab of the Chair of Casting Process Engineering, Faculty of Foundry Engineering, AGH University of Science and Technology concerning the physical chemistry of polymer casting binders.

  5. Polymer nanocomposites reinforced with montmorillonite

    OpenAIRE

    L.A. Dobrzański; M. Bilewicz; Viana, J. C.

    2012-01-01

    Purpose: Light microscope with polarized light has been used for observation layered zone, visible thanks to polarization of the light, inside polymer-polymer composites and nanocomposites Aim of work has been concentrated on investigation of nanocomposites as promising engineering materials, basing on composition of polypropylene and montmorillonite as reinforcement in the shape of nanoparticles of 2:1 silicate.Design/methodology/approach: Conventional and non-conventional injection molding ...

  6. Polymer compositions based on PXE

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jin; Eitouni, Hany Basam; Singh, Mohit

    2015-09-15

    New polymer compositions based on poly(2,6-dimethyl-1,4-phenylene oxide) and other high-softening-temperature polymers are disclosed. These materials have a microphase domain structure that has an ionically-conductive phase and a phase with good mechanical strength and a high softening temperature. In one arrangement, the structural block has a softening temperature of about 210.degree. C. These materials can be made with either homopolymers or with block copolymers.

  7. Changes in molecular structure and properties of irradiated polymers of different compositions - ESR and NMR study

    International Nuclear Information System (INIS)

    Investigations of molecular structural changes in polymers during exposure to high energy radiation is the long term interest of the Polymer Materials and Radiation Group at the University of Queensland. Recently, the group had looked at a range of polymers including natural and synthetic rubbers, methacrylates and polyesters. The objective of the work has been to investigate the relationships between polymer structure and sensitivity towards high energy radiation, including gamma radiation. This report will focus on the Electron Spin Resonance (ESR) and Nuclear Magnetic Resonance (NMR) studies of the effects of gamma irradiation on these polymers. Other methods such as Gas Chromatography (GC), Gel Permeation Chromatography (GPC), Fourier Transformed Infra Red (FTIR), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA) and Dynamic Mechanical Analysis (DMA) have also been used as these methods combine with ESR and NMR, to provide a more complete picture of the mechanism of the structural changes. (author)

  8. Biomaterials for periodontal regeneration: a review of ceramics and polymers.

    Science.gov (United States)

    Shue, Li; Yufeng, Zhang; Mony, Ullas

    2012-01-01

    Periodontal disease is characterized by the destruction of periodontal tissues. Various methods of regenerative periodontal therapy, including the use of barrier membranes, bone replacement grafts, growth factors and the combination of these procedures have been investigated. The development of biomaterials for tissue engineering has considerably improved the available treatment options above. They fall into two broad classes: ceramics and polymers. The available ceramic-based materials include calcium phosphate (eg, tricalcium phosphate and hydroxyapatite), calcium sulfate and bioactive glass. The bioactive glass bonds to the bone with the formation of a layer of carbonated hydroxyapatite in situ. The natural polymers include modified polysaccharides (eg, chitosan,) and polypeptides (collagen and gelatin). Synthetic polymers [eg, poly(glycolic acid), poly(L-lactic acid)] provide a platform for exhibiting the biomechanical properties of scaffolds in tissue engineering. The materials usually work as osteogenic, osteoconductive and osteoinductive scaffolds. Polymers are more widely used as a barrier material in guided tissue regeneration (GTR). They are shown to exclude epithelial downgrowth and allow periodontal ligament and alveolar bone cells to repopulate the defect. An attempt to overcome the problems related to a collapse of the barrier membrane in GTR or epithelial downgrowth is the use of a combination of barrier membranes and grafting materials. This article reviews various biomaterials including scaffolds and membranes used for periodontal treatment and their impacts on the experimental or clinical management of periodontal defect.

  9. From chromosome crumpling to the interacting randomly branched polymers

    Science.gov (United States)

    Everaers, Ralf

    The conformational statistics of ring polymers in melts or dense solutions is strongly affected by their quenched microscopic topological state. The effect is particularly strong for non-concatenated unknotted rings, which are known to crumple and segregate and which have been implicated as models for the generic behavior of interphase chromosomes. In we have used a computationally efficient multi-scale approach to identify the subtle physics underlying their behavior, where we combine massive Molecular Dynamics simulations on the fiber level with Monte Carlo simulations of a wide range of lattice models for the large scale structure. This allowed us to show that ring melts can be quantitatively mapped to coarse-grained melts of interacting randomly branched primitive paths. To elucidate the behavior of interacting branched polymers, we use a combination of scaling arguments and computer simulations. The simulations are carried out for different statistical ensembles: ideal randomly branching polymers, melts of interacting randomly branching polymers, and self-avoiding trees with annealed and quenched connectivities. In all cases, we perform a detailed analysis of the tree connectivities and conformations. We find that the scaling behaviour of average properties is very well described by the Flory theory of Gutin et al. [Macromolecules 26, 1293 (1993)]. A detailed study of the corresponding distribution functions allows us to propose a coherent framework of the behavior of interacting trees, including generalised Fisher-Pincus relationships and the detailed analysis of contacts statistics.

  10. Physical properties of Li ion conducting polyphosphazene based polymer electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Sanderson, S.; Zawodzinski, T.; Hermes, R.; Davey, J.; Dai, Hongli

    1996-12-31

    We report a systematic study of the transport properties and the underlying physical chemistry of some polyphosphazene (PPhz)-based polymer electrolytes. We synthesized MEEP and variants which employed mixed combinations of different length oxyethylene side-chains. We compare the conductivity and ion-ion interactions in polymer electrolytes obtained with lithium triflate and lithium bis(trifluoromethanesulfonyl)imide (TFSI) salts added to the polymer. The combination of the lithium imide salt and MEEP yields a maximum conductivity of 8 x 10{sup -5} {Omega}{sup -1} cm{sup -1} at room temperature at a salt loading of 8 monomers per lithium. In one of the mixed side-chain variations, a maximum conductivity of 2 x 10{sup -4} {Omega}{sup -1} cm{sup -1} was measured at the same molar ratio. Raman spectral analysis shows some ion aggregation and some polymer - ion interactions in the PPhz-LiTFSI case but much less than observed with Li CF{sub 3}SO{sub 3}. A sharp increase in the Tg as salt is added corresponds to concentrations above which the conductivity significantly decreases and ion associations appear.

  11. Towards Monodispersed Polymer Microspheres

    Science.gov (United States)

    Senuma, Yoshinori; Hilborn, Jons

    1998-03-01

    Uniform polymer microspheres prepared by Spinning Disk Atomization Our spinning disk atomization (SDA) can, relative to other existing techniques, produce micron-sized particles of very narrow size distribution. Around the edge of the disk, small teeth channel the flow into identical droplets that are flung off over the disk rim. These solidify during flight to form spherical particles. Applications for spheres produced by SDA can be found in areas such as adhesives, powder coatings, food, biomedical use, drug delivery systems, etc. We have atomized polyethyleneglycol into very narrowly dispersed microspheres ranging from 50 to 500 =B5m. The aim of this work is to model the droplet formation occurring at the rim of the spinning disk in order to better understand the experimental results. The viscosity contribution in the fluid breakup is qualitatively analyzed and is adapted to the theoretical model to show how it affects the droplet size. We have used the pendant drop model (Ramesh Babu, S. Journal of Colloid and Interface Science 116, 350-372 (1987).) for spinning disk atomization to describe the drop-shape evolution during growth.

  12. 高分子合金膜体系的相容性%Polymer blend miscibility and compatibility study for polymer alloy membrane material modification

    Institute of Scientific and Technical Information of China (English)

    孙本惠

    2011-01-01

    Polymer alloy technologies enable two or more polymers to be combined to realize new properties and levels of performance that were not possible with the individual polymers themselves. Therefore, they have become the most feasible and effective methods to realize the modification of polymeric membrane materials. The miscibility and compatibility of the various polymeric components, and thus the formation of homogenious phase to multiphase systems in casting solution play a decisive role in influencing the physical properties of the membranes prepared from it. In this article, the principles of thermodynamic to evaluate the miscibility and compatibility between polymers in polymer blend or alloy systems were thoroughly reviewed and discussed, including the basic theory and models for polymer miscibility study, the analysis of the ternary phase diagram of polymer A-polymer Insolvent mixture system, the thermodynamics of polymer blend phase separation during phase inversion, the critical phase separation condition, and the theoretical prediction of the polymer blend miscibility and compatibility.%高分子膜材料的合金化是最为简便有效的膜材料改性方法,不同聚合物之间的相容性是决定高分子合金膜物理性质的关键因素.文章讨论了涉及高分子合金膜体系相容性的几个主要热力学基础问题,包括两组分聚合物相容性的相图分析、高分子共混物在相转化过程中发生相分离的热力学、相分离的临界条件、高分子合金体系相容性的理论预测.

  13. Efficiency Improvement of Heterojunction Polymer Photovoltaic Cells through Controlling the Morphology of the Polymer Film

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1 Results Polymer photovoltaic cells, which provide clean and renewable energy sources, have gained more and more attention. Polymer photovoltaic cells have the advantage of low fabrication cost and high mechanical flexibility. Polymers can be processed through a solution process, so that a homogeneous polymer film could be readily prepared in a large area. Recently, the light-to-electricity conversion efficiency of the polymer photovoltaic cells was improved significantly[1-2]. Polymer donor and organi...

  14. A polymer surfactant corona dynamically replaces water in solvent-free protein liquids and ensures macromolecular flexibility and activity.

    Science.gov (United States)

    Gallat, François-Xavier; Brogan, Alex P S; Fichou, Yann; McGrath, Nina; Moulin, Martine; Härtlein, Michael; Combet, Jérôme; Wuttke, Joachim; Mann, Stephen; Zaccai, Giuseppe; Jackson, Colin J; Perriman, Adam W; Weik, Martin

    2012-08-15

    The observation of biological activity in solvent-free protein-polymer surfactant hybrids challenges the view of aqueous and nonaqueous solvents being unique promoters of protein dynamics linked to function. Here, we combine elastic incoherent neutron scattering and specific deuterium labeling to separately study protein and polymer motions in solvent-free hybrids. Myoglobin motions within the hybrid are found to closely resemble those of a hydrated protein, and motions of the polymer surfactant coating are similar to those of the hydration water, leading to the conclusion that the polymer surfactant coating plasticizes protein structures in a way similar to hydration water.

  15. Application of the van der Waals equation of state to polymers .4. Correlation and prediction of lower critical solution temperatures for polymer solutions

    DEFF Research Database (Denmark)

    Goncalves, Ana Saraiva; Kontogeorgis, Georgios; Harismiadis, Vassilis I.;

    1996-01-01

    The van der Waals equation of state is used for the correlation and the prediction of the lower critical solution behavior or mixtures including a solvent and a polymer. The equation of state parameters for the polymer are estimated from experimental volumetric data at low pressures. The equation...... of state parameters for the solvent are estimated via the classical Soave method, i.e. using the critical properties and a generalized equation for the energy parameter. When extended to mixtures, the van der Waals one-fluid mixing rules along with the Berthelot combining rule for the molecular cross...... energy parameter are used. The arithmetic mean combining rule is used for the cross co-volume parameter. The deviations from the Berthelot combining rule are taken into account via a simple expression which has been previously obtained from vapor-liquid equilibrium data of athermal polymer solutions...

  16. Dihydroxybenzene/benzoquinone-containing polymers: organic redox polymers

    Energy Technology Data Exchange (ETDEWEB)

    Moulay, S. [Universite de Blida, Lab. de Chimie-Physique Macromoleculaire, Institut de Chimie Industrielle (Algeria)

    2000-08-01

    Polymers containing hydroquinone, catechol or their corresponding benzoquinones are a special class of redox polymers. Three pathways of their syntheses are possible: condensation polymerization of suitable monomers, addition polymerization of vinyl monomers containing redox moiety, and chemical attachment of redox unit onto pre-made polymeric matrix. A range of functionalized matrices have been employed such as polyethers, polyesters, polycarbonates, polyurethanes, polyamides and others. Protection of their phenolic functionality has conducted to chemically interesting redox polymer precursors. The presence of a redox moiety coupled with the extant functionalization of the polymer matrix makes the materials very valuable, of wide properties and consequently of vast applicability. For instance, in the oil field, some polymers such as carboxy-methyl-cellulose (CMC) are often applied as to bring about a viscosity improvement and therefore to facilitate the oil drilling. In this regard, Patel evaluated sulfo-alkylated polymeric catechol, namely sulfo-methylated and sulfo-ethylated resins. Indeed, polymeric catechol chemically modified as such exhibited a marked ability to control the viscosity, the gel strength, as well as the filtrate loss of aqueous oil drilling fluids.

  17. Polymer Stamps for Imprinting Nanopatterns in Polymer Substrate.

    Science.gov (United States)

    Wu, Jiahao; Amirsadeghi, Alborz; Kim, Jinsoo; Park, Sunggook

    2015-01-01

    Using a silicone or metallic stamp for imprinting multiscale patterns comprising micro down to nanoscale patterns into polymer substrates often results in significant deformation in the molded substrate and loss of pattern transfer fidelity for nanopatterns. In the worst case, the expensive stamp can also be damaged. One method to reduce the problem is to use polymer as the stamp material, which will reduce both adhesion and thermal stress generated at the stamp/substrate interface. In this paper, stamps made of three different polymer materials, i.e., polydimethylsiloxane (PDMS), PPGDA-based UV resin and TPGDA-based UV-resin, were fabricated from the same master containing nanofluidic structures and the replication fidelity from the master, polymer stamps, to thermal-imprinted poly(methyl methacrylate) substrate (PMMA) was compared. The largest loss of pattern fidelity occurs in the thermal imprinting step. Polymer stamps with higher Young's moduli result in a better fidelity in pattern transfer. With TPGDA-based UV resin stamps, multiscale structures with a nanochannel with minimum width and height of -70 nm can be imprinted onto PMMA substrate together with macro-scale patterns by a single nanoimprinting processes. PMID:26328384

  18. Quantitative equivalence between polymer nanocomposites and thin polymer films.

    Science.gov (United States)

    Bansal, Amitabh; Yang, Hoichang; Li, Chunzhao; Cho, Kilwon; Benicewicz, Brian C; Kumar, Sanat K; Schadler, Linda S

    2005-09-01

    The thermomechanical responses of polymers, which provide limitations to their practical use, are favourably altered by the addition of trace amounts of a nanofiller. However, the resulting changes in polymer properties are poorly understood, primarily due to the non-uniform spatial distribution of nanoparticles. Here we show that the thermomechanical properties of 'polymer nanocomposites' are quantitatively equivalent to the well-documented case of planar polymer films. We quantify this equivalence by drawing a direct analogy between film thickness and an appropriate experimental interparticle spacing. We show that the changes in glass-transition temperature with decreasing interparticle spacing for two filler surface treatments are quantitatively equivalent to the corresponding thin-film data with a non-wetting and a wetting polymer-particle interface. Our results offer new insights into the role of confinement on the glass transition, and we conclude that the mere presence of regions of modified mobility in the vicinity of the particle surfaces, that is, a simple two-layer model, is insufficient to explain our results. Rather, we conjecture that the glass-transition process requires that the interphase regions surrounding different particles interact. PMID:16086021

  19. Nanostructured polymer membranes for proton conduction

    Science.gov (United States)

    Balsara, Nitash Pervez; Park, Moon Jeong

    2013-06-18

    Polymers having an improved ability to entrain water are characterized, in some embodiments, by unusual humidity-induced phase transitions. The described polymers (e.g., hydrophilically functionalized block copolymers) have a disordered state and one or more ordered states (e.g., a lamellar state, a gyroid state, etc.). In one aspect, the polymers are capable of undergoing a disorder-to-order transition while the polymer is exposed to an increasing temperature at a constant relative humidity. In some aspects the polymer includes a plurality of portions, wherein a first portion forms proton-conductive channels within the membrane and wherein the channels have a width of less than about 6 nm. The described polymers are capable of entraining and preserving water at high temperature and low humidity. Surprisingly, in some embodiments, the polymers are capable of entraining greater amounts of water with the increase of temperature. The polymers can be used in Polymer Electrolyte Membranes in fuel cells.

  20. Mechanics of biological polymer composites

    Science.gov (United States)

    Lomakin, Joseph

    2009-12-01

    displayed a darker coloration and significantly increased n of 0.0470.004, suggesting both cuticles to be less cross-linked, a finding consistent with reduced beta-alanine metabolism. Suppression of the tanning enzyme laccase2 (TcLac2) resulted in a pale cuticle with an n of 0.043+/-0.005, implicating laccases in the formation of both pigments and cross-links during sclerotization. Cuticular cross-linking was increased and n decreased with decreased expression of structural proteins, CP10 and CP20. This work establishes n as an important novel parameter for confirming metabolic pathways within load bearing tissues and for understanding structure function relationships within biological polymer composites. Additionally, Tribolium castaneum elytral indentation modulus (800+/-200 MPa) was determined by nanoindentation and a 4nm regular hexagonal pattern on the dorsal side of elytra investigated via scanning, transmission and atomic microscopy. Based on studied biological materials, the combination of rigid macromolecules immersed in a ductile matrix was found to be significant in achieving exceptional mechanical performance. Inspired by this biological design principle, the synthesis, properties and structure of Poly(ethylene glycol) diacrylate/agarose semi-interpenetrating network hydrogels were explored. The resulting novel composite materials were 9x stiffer than agarose and 5x tougher than PEGDA alone and showed good biocompatibility, suggesting promise as a scaffold material for tissue engineering constructs for cartilage regeneration.