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Sample records for amorphous polymer solution

  1. The sorption induced glass transition in amorphous glassy polymers

    NARCIS (Netherlands)

    van der Vegt, N.F.A.; Wessling, Matthias; Strathmann, H.; Briels, Willem J.

    1999-01-01

    Sorption of CO2 in both the glassy and the rubbery state of an amorphous polyethylenelike polymer was investigated using molecular dynamics simulations. The temperature was chosen such that the system was in its glassy state at low solute concentrations and its rubbery state at large solute

  2. Magnetoimpedance of cobalt-based amorphous ribbons/polymer composites

    Energy Technology Data Exchange (ETDEWEB)

    Semirov, A.V., E-mail: semirov@mail.ru [Irkutsk State University, Irkutsk (Russian Federation); Derevyanko, M.S.; Bukreev, D.A.; Moiseev, A.A.; Kudryavtsev, V.O. [Irkutsk State University, Irkutsk (Russian Federation); Safronov, A.P. [Ural Federal University, Yekaterinburg (Russian Federation)

    2016-10-01

    The combined influence of the temperature, the elastic tensile stress and the external magnetic field on the total impedance and impedance components were studied for rapidly quenched amorphous Co{sub 75}Fe{sub 5}Si{sub 4}B{sub 16} ribbons. Both as-cast amorphous ribbons and Co{sub 75}Fe{sub 5}Si{sub 4}B{sub 16}/polymer amorphous ribbon based composites were considered. Following polymer coverings were studied: modified rubber solution in o-xylene, solution of butyl methacrylate and methacrylic acid copolymer in isopropanol and solution of polymethylphenylsiloxane resin in toluene. All selected composites showed very good adhesion of the coverings and allowed to provide temperature measurements from 163 K up to 383 K under the applied deforming tensile force up to 30 N. The dependence of the modulus of the impedance and its components on the external magnetic field was influenced by the elastic tensile stresses and was affected by the temperature of the samples. It was shown that maximal sensitivity of the impedance and its components to the external magnetic field was observed at minimal temperature and maximal deforming force depended on the frequency of an alternating current. - Highlights: • Impedance and its components of amorphous Co{sub 75}Fe{sub 5}Si{sub 4}B{sub 16} ribbons were studied. • MI sensitivity to the magnetic field depends on a temperature and a deforming force. • Polymer covering can affect the functional properties of the composite.

  3. Initial Drug Dissolution from Amorphous Solid Dispersions Controlled by Polymer Dissolution and Drug-Polymer Interaction.

    Science.gov (United States)

    Chen, Yuejie; Wang, Shujing; Wang, Shan; Liu, Chengyu; Su, Ching; Hageman, Michael; Hussain, Munir; Haskell, Roy; Stefanski, Kevin; Qian, Feng

    2016-10-01

    To identify the key formulation factors controlling the initial drug and polymer dissolution rates from an amorphous solid dispersion (ASD). Ketoconazole (KTZ) ASDs using PVP, PVP-VA, HMPC, or HPMC-AS as polymeric matrix were prepared. For each drug-polymer system, two types of formulations with the same composition were prepared: 1. Spray dried dispersion (SDD) that is homogenous at molecular level, 2. Physical blend of SDD (80% drug loading) and pure polymer (SDD-PB) that is homogenous only at powder level. Flory-Huggins interaction parameters (χ) between KTZ and the four polymers were obtained by Flory-Huggins model fitting. Solution (13)C NMR and FT-IR were conducted to investigate the specific drug-polymer interaction in the solution and solid state, respectively. Intrinsic dissolution of both the drug and the polymer from ASDs were studied using a Higuchi style intrinsic dissolution apparatus. PXRD and confocal Raman microscopy were used to confirm the absence of drug crystallinity on the tablet surface before and after dissolution study. In solid state, KTZ is completely miscible with PVP, PVP-VA, or HPMC-AS, demonstrated by the negative χ values of -0.36, -0.46, -1.68, respectively; while is poorly miscible with HPMC shown by a positive χ value of 0.23. According to solution (13)C NMR and FT-IR studies, KTZ interacts with HPMC-AS strongly through H-bonding and dipole induced interaction; with PVPs and PVP-VA moderately through dipole-induced interactions; and with HPMC weakly without detectable attractive interaction. Furthermore, the "apparent" strength of drug-polymer interaction, measured by the extent of peak shift on NMR or FT-IR spectra, increases with the increasing number of interacting drug-polymer pairs. For ASDs with the presence of considerable drug-polymer interactions, such as KTZ/PVPs, KTZ/PVP-VA, or KTZ /HPMC-AS systems, drug released at the same rate as the polymer when intimate drug-polymer mixing was ensured (i.e., the SDD systems

  4. Phenomenology of polymer solution dynamics

    National Research Council Canada - National Science Library

    Phillies, George D. J

    2011-01-01

    ... solutions, not dilute solutions or polymer melts. From centrifugation and solvent dynamics to viscosity and diffusion, experimental measurements and their quantitative representations are the core of the discussion...

  5. Laser Photolytic Approach to Cu/polymer Sols and Cu/polymer Nanocomposites with Amorphous Cu Phase.

    Czech Academy of Sciences Publication Activity Database

    Pola, Josef; Ouchi, A.; Bakardjieva, Snejana; Urbanová, Markéta; Boháček, Jaroslav; Šubrt, Jan

    2007-01-01

    Roč. 192, 2-3 (2007) , s. 84-92 ISSN 1010-6030 Institutional research plan: CEZ:AV0Z40720504; CEZ:AV0Z40320502 Keywords : Cu-polymer nanocomposite * laser solution photolysis * amorphous Cu phase Subject RIV: CH - Nuclear ; Quantum Chemistry Impact factor: 1.911, year: 2007

  6. Enhanced Physical Stability of Amorphous Drug Formulations via Dry Polymer Coating.

    Science.gov (United States)

    Capece, Maxx; Davé, Rajesh

    2015-06-01

    Although amorphous solid drug formulations may be advantageous for enhancing the bioavailability of poorly soluble active pharmaceutical ingredients, they exhibit poor physical stability and undergo recrystallization. To address this limitation, this study investigates stability issues associated with amorphous solids through analysis of the crystallization behavior for acetaminophen (APAP), known as a fast crystallizer, using a modified form of the Avrami equation that kinetically models both surface and bulk crystallization. It is found that surface-enhanced crystallization, occurring faster at the free surface than in the bulk, is the major impediment to the stability of amorphous APAP. It is hypothesized that a novel use of a dry-polymer-coating process referred to as mechanical-dry-polymer-coating may be used to inhibit surface crystallization and enhance stability. The proposed process, which is examined, simultaneously mills and coats amorphous solids with polymer, while avoiding solvents or solutions, which may otherwise cause stability or crystallization issues during coating. It is shown that solid dispersions of APAP (64% loading) with a small particle size (28 μm) could be prepared and coated with the polymer, carnauba wax, in a vibratory ball mill. The resulting amorphous solid was found to have excellent stability as a result of inhibition of surface crystallization. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  7. Amorphization of thiamine chloride hydrochloride: A study of the crystallization inhibitor properties of different polymers in thiamine chloride hydrochloride amorphous solid dispersions.

    Science.gov (United States)

    Arioglu-Tuncil, Seda; Bhardwaj, Vivekanand; Taylor, Lynne S; Mauer, Lisa J

    2017-09-01

    Amorphous solid dispersions of thiamine chloride hydrochloride (THCl) were created using a variety of polymers with different physicochemical properties in order to investigate how effective the various polymers were as THCl crystallization inhibitors. THCl:polymer dispersions were prepared by lyophilizing solutions of THCl and amorphous polymers (guar gum, pectin, κ-carrageenan, gelatin, and polyvinylpyrrolidone (PVP)). These dispersions were stored at select temperature (25 and 40°C) and relative humidity (0, 23, 32, 54, 75, and 85% RH) conditions and monitored at different time points using powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). Moisture sorption isotherms of all samples were also obtained. Initially amorphous THCl was produced in the presence of ≥40% w/w pectin, κ-carrageenan, gelatin, and guar gum or ≥60% w/w PVP. Trends in polymer THCl crystallization inhibition (pectin≥κ-carrageenan>gelatin>guar gum≫PVP) were primarily based on the ability of the polymer to interact with THCl via hydrogen bonding and/or ionic interactions. The onset of THCl crystallization from the amorphous dispersions was also related to storage conditions. THCl remained amorphous at low RH conditions (0 and 23% RH) in all 1:1 dispersions except THCl:PVP. THCl crystallized in some dispersions below the glass transition temperature (T g ) but remained amorphous in others at T~T g . At high RHs (75 and 85% RH), THCl crystallized within one day in all samples. Given the ease of THCl amorphization in the presence of a variety of polymers, even at higher vitamin concentrations than would be found in foods, it is likely that THCl is amorphous in many low moisture foods. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Thermal transitions of the amorphous polymers in wheat straw

    DEFF Research Database (Denmark)

    Stelte, Wolfgang; Clemons, Craig; Holm, Jens K.

    2011-01-01

    The thermal transitions of the amorphous polymers in wheat straw were investigated using dynamic mechanical thermal analysis (DMTA). The study included both natural and solvent extracted wheat straw, in moist (8–9% water content) and dry conditions, and was compared to spruce samples. Under...

  9. Physical stability of API/polymer-blend amorphous solid dispersions.

    Science.gov (United States)

    Lehmkemper, Kristin; Kyeremateng, Samuel O; Bartels, Mareike; Degenhardt, Matthias; Sadowski, Gabriele

    2018-03-01

    The preparation of amorphous solid dispersions (ASDs) is a well-established strategy for formulating active pharmaceutical ingredients by embedding them in excipients, usually amorphous polymers. Different polymers can be combined for designing ASDs with desired properties like an optimized dissolution behavior. One important criterion for the development of ASD compositions is the physical stability. In this work, the physical stability of API/polymer-blend ASDs was investigated by thermodynamic modeling and stability studies. Amorphous naproxen (NAP) and acetaminophen (APAP) were embedded in blends of hydroxypropyl methylcellulose acetate succinate (HPMCAS) and either poly(vinylpyrrolidone) (PVP) or poly(vinylpyrrolidone-co-vinyl acetate) (PVPVA64). Parameters for modeling the API solubility in the blends and the glass-transition temperature curves of the water-free systems with Perturbed-Chain Statistical Associating Fluid Theory and Kwei equation, respectively, were correlated to experimental data. The phase behavior for standardized storage conditions (0%, 60% and 75% relative humidity (RH)) was predicted and compared to six months-long stability studies. According to modeling and experimental results, the physical stability was reduced with increasing HPMCAS content and increasing RH. This trend was observed for all investigated systems, with both APIs (NAP and APAP) and both polymer blends (PVP/HPMCAS and PVPVA64/HPMCAS). PC-SAFT and the Kwei equation turned out to be suitable tools for modeling and predicting the physical stability of the investigated API/polymer-blends ASDs. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Network approach towards understanding the crazing in glassy amorphous polymers

    Science.gov (United States)

    Venkatesan, Sudarkodi; Vivek-Ananth, R. P.; Sreejith, R. P.; Mangalapandi, Pattulingam; Hassanali, Ali A.; Samal, Areejit

    2018-04-01

    We have used molecular dynamics to simulate an amorphous glassy polymer with long chains to study the deformation mechanism of crazing and associated void statistics. The Van der Waals interactions and the entanglements between chains constituting the polymer play a crucial role in crazing. Thus, we have reconstructed two underlying weighted networks, namely, the Van der Waals network and the entanglement network from polymer configurations extracted from the molecular dynamics simulation. Subsequently, we have performed graph-theoretic analysis of the two reconstructed networks to reveal the role played by them in the crazing of polymers. Our analysis captured various stages of crazing through specific trends in the network measures for Van der Waals networks and entanglement networks. To further corroborate the effectiveness of network analysis in unraveling the underlying physics of crazing in polymers, we have contrasted the trends in network measures for Van der Waals networks and entanglement networks in the light of stress-strain behaviour and voids statistics during deformation. We find that the Van der Waals network plays a crucial role in craze initiation and growth. Although, the entanglement network was found to maintain its structure during craze initiation stage, it was found to progressively weaken and undergo dynamic changes during the hardening and failure stages of crazing phenomena. Our work demonstrates the utility of network theory in quantifying the underlying physics of polymer crazing and widens the scope of applications of network science to characterization of deformation mechanisms in diverse polymers.

  11. Preparation and characterization of polymer-derived amorphous silicon carbide with silicon-rich stoichiometry

    Energy Technology Data Exchange (ETDEWEB)

    Masuda, Takashi, E-mail: mtakashi@jaist.ac.jp [School of Material and Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); Iwasaka, Akira [School of Material and Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); Takagishi, Hideyuki [Faculty of Symbiotic System Science, Fukushima University, 1 Kanayagawa, Fukushima-shi, Fukushima 960-1296 (Japan); Shimoda, Tatsuya [School of Material and Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan)

    2016-08-01

    Polydihydrosilane with pendant hexyl groups was synthesized to obtain silicon-rich amorphous silicon carbide (a-SiC) films via the solution route. Unlike conventional polymeric precursors, this polymer requires neither catalysts nor oxidation for its synthesis and cross-linkage. Therefore, the polymer provides sufficient purity for the fabrication of semiconducting a-SiC. Here, we investigated the correlation of Si/C stoichiometry between the polymer and the resultant a-SiC film. The structural, optical, and electrical properties of the films with various carbon contents were also explored. Experimental results suggested that the excess carbon that did not participate in Si−C configurations was decomposed and was evaporated during polymer-to-SiC conversion. Consequently, the upper limit of the carbon in resultant a-SiC film was < 50 at.%; namely, the polymer provided silicon-rich a-SiC, whereas the conventionally used polycarbosilane inevitably provides carbon-rich one. These features of this unusual polymer open up a frontier of polymer-derived SiC and solution-processed SiC electronics. - Highlights: • Polymeric precursor solution for silicon carbide (SiC) is synthesized. • Semiconducting amorphous SiC is prepared via solution route. • The excess carbon is decomposed during cross-linking resulting in Si-rich SiC films. • The grown SiC films contain substantial amount of hydrogen atoms as SiH{sub n}/CH{sub n} entities. • Presence of CH{sub n} entities induces dangling bonds, causing poor electrical properties.

  12. Dielectric breakdown in silica-amorphous polymer nanocomposite films: the role of the polymer matrix.

    Science.gov (United States)

    Grabowski, Christopher A; Fillery, Scott P; Westing, Nicholas M; Chi, Changzai; Meth, Jeffrey S; Durstock, Michael F; Vaia, Richard A

    2013-06-26

    The ultimate energy storage performance of an electrostatic capacitor is determined by the dielectric characteristics of the material separating its conductive electrodes. Polymers are commonly employed due to their processability and high breakdown strength; however, demands for higher energy storage have encouraged investigations of ceramic-polymer composites. Maintaining dielectric strength, and thus minimizing flaw size and heterogeneities, has focused development toward nanocomposite (NC) films; but results lack consistency, potentially due to variations in polymer purity, nanoparticle surface treatments, nanoparticle size, and film morphology. To experimentally establish the dominant factors in broad structure-performance relationships, we compare the dielectric properties for four high-purity amorphous polymer films (polymethyl methacrylate, polystyrene, polyimide, and poly-4-vinylpyridine) incorporating uniformly dispersed silica colloids (up to 45% v/v). Factors known to contribute to premature breakdown-field exclusion and agglomeration-have been mitigated in this experiment to focus on what impact the polymer and polymer-nanoparticle interactions have on breakdown. Our findings indicate that adding colloidal silica to higher breakdown strength amorphous polymers (polymethyl methacrylate and polyimide) causes a reduction in dielectric strength as compared to the neat polymer. Alternatively, low breakdown strength amorphous polymers (poly-4-vinylpyridine and especially polystyrene) with comparable silica dispersion show similar or even improved breakdown strength for 7.5-15% v/v silica. At ∼15% v/v or greater silica content, all the polymer NC films exhibit breakdown at similar electric fields, implying that at these loadings failure becomes independent of polymer matrix and is dominated by silica.

  13. Dynamic viscosity of polymer solutions

    Energy Technology Data Exchange (ETDEWEB)

    Peterlin, A

    1982-03-01

    The dynamic viscosity investigation of solutions of long chain polymers in very viscous solvents has definitely shown the existence of the low and high frequency plateau with the gradual transition between them. In both extreme cases the extrapolation of the measured Newtonian viscosities of the plateaus to the infinite dilution yields the limiting intrinsic viscosities. Such a behavior is expected from the dynamic intrinsic viscosity of the necklace model of the linear polymer with finite internal viscosity. The plateau at low frequency shows up in any model of polymer solution. This work shows the constant dynamic intrinsic viscosity in both extreme cases is well reproducible by the necklace model with the internal viscosity acting only between the beads on the same link. 20 references.

  14. Amorphous metallic alloys for oxygen reduction reaction in a polymer electrolyte membrane fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Huerta, R.; Guerra-Martinez, I.; Lopez, J.S. [Inst. Politecnico Nacional, ESIQIE, Mexico City (Mexico). Lab. de Electroquimica; Pierna, A.R. [Basque Country Univ., San Sebastian (Spain). Dept. of Chemical Engineering and Environment; Solorza-Feria, O. [Inst. Politenico Nacional, Centro de Investigacion y de Estudios Avanzados, Mexico City (Mexico). Dept. de Quimica

    2010-07-15

    Direct methanol fuel cells (DMFC) and polymer electrolyte membrane fuel cells (PEMFC) represent an important, environmentally clean energy source. This has motivated extensive research on the synthesis, characterization and evaluation of novel and stable oxygen reduction electrocatalysts for the direct four-electron transfer process to water formation. Studies have shown that amorphous alloyed compounds can be used as electrode materials in electrochemical energy conversion devices. Their use in PEMFCs can optimize the electrocatalyst loading in the membrane electrode assembly (MEA). In this study, amorphous metallic PtSn, PtRu and PtRuSn alloys were synthesized by mechanical milling and used as cathodes for the oxygen reduction reaction (ORR) in sulphuric acid and in a single PEM fuel cell. Two different powder morphologies were observed before and after the chemical activation in a hydrofluoric acid (HF) solution at 25 degrees C. The kinetics of the ORR on the amorphous catalysts were investigated. The study showed that the amorphous metallic PtSn electrocatalyst was the most active of the 3 electrodes for the cathodic reaction. Fuel cell experiments were conducted at various temperatures at 30 psi for hydrogen (H{sub 2}) and at 34 psi for oxygen (O{sub 2}). MEAs made of Nafion 115 and amorphous metallic PtSn dispersed on carbon powder in a PEMFC had a power density of 156 mW per cm{sup 2} at 0.43V and 80 degrees C. 12 refs., 1 tab., 5 figs.

  15. Monolithic amorphous silicon modules on continuous polymer substrate

    Energy Technology Data Exchange (ETDEWEB)

    Grimmer, D.P. (Iowa Thin Film Technologies, Inc., Ames, IA (United States))

    1992-03-01

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

  16. Glass solution formation in water - In situ amorphization of naproxen and ibuprofen with Eudragit® E PO

    DEFF Research Database (Denmark)

    Doreth, Maria; Löbmann, Korbinian; Grohganz, Holger

    2016-01-01

    is applicable to other drugs. Compacts of drug and Eudragit® E were compressed at a 2:1, 1:1 and 1:2 drug-to-polymer ratio (w/w) and immersed in water for 1 h. Physicochemical characteristics, potential interactions and dissolution behavior were analyzed and compared to non-immersed compacts. Both drugs formed...... a glass solution with Eudragit® E when immersed into water. In XRPD, reflections of the respective drugs decreased or disappeared completely. All samples showed a single glass transition temperature in the DSC, suggesting the formation of single phase amorphous systems. Ionic interactions between drug...... and polymer were identified by infrared spectroscopy. In the dissolution study (pH 4.1), especially the 1:1 (w/w) in situ amorphized samples showed an improved dissolution behavior compared to their non-immersed counterparts. It can be concluded that in situ amorphization is a promising method to amorphize...

  17. Production of amorphous starch powders by solution spray drying

    NARCIS (Netherlands)

    Niazi, Muhammad B. K.; Broekhuis, Antonius A.

    2012-01-01

    The spray drying of starch/maltodextrin formulations was evaluated as a potential technology for the manufacturing of amorphous thermoplastic starches. Mixtures of starches with high to low amylose (Am)amylopectin (Ap) ratios were spray-dried from water-based solutions and granular dispersions. The

  18. Free-volume micro-structure of the amorphous polymers at Tg

    International Nuclear Information System (INIS)

    Bartos, J.

    1995-01-01

    The positron annihilation spectroscopy was used to the study of the free-volume microstructure of the amorphous polymers [diene-elastomers, vinyl-elastomers and thermoplastics, aromatic thermoplastics

  19. Inhibition of surface crystallisation of amorphous indomethacin particles in physical drug-polymer mixtures

    DEFF Research Database (Denmark)

    Priemel, Petra A; Laitinen, Riikka; Barthold, Sarah

    2013-01-01

    stability than pure IMC whereas IMC Soluplus(®) mixtures did not. Water uptake was higher for mixtures containing Soluplus(®) than for amorphous IMC or IMC Eudragit(®) mixtures. However, the Tg of amorphous IMC was unaffected by the presence (and nature) of polymer. SEM revealed that Eudragit(®) particles...... through reduced IMC surface molecular mobility. Polymer particles may also mechanically hinder crystal growth outwards from the surface. This work highlights the importance of microparticulate surface coverage of amorphous drug particles on their stability....

  20. Dynamics of dilute polymer solutions

    International Nuclear Information System (INIS)

    Nicholson, L.K.; Higgins, J.S.

    1980-01-01

    Neutrons scattered by nuclei undergoing slow motion e.g. the internal motion within polymer chains, lose or gain very small amounts of energy. It is therefore the quasi-elastic region of the neutron scattering spectrum which is of interest and in particular the time correlation function (or intermediate scattering law S(Q,t)) which is ideally required to define the motion. The neutron spin echo spectrometer (IN11) at the ILL facilitates the measurement of very small energy changes (down to 10 neV) on scattering from a sample, by changing and keeping track of neutron beam polarization non-parallel to the magnetic guide-field (1). The resultant neutron beam polarization, when normalized against a standard (totally elastic) scatterer is directly proportional to the cosine Fourier Transform of the scattering law S(Q,ω), which is to say the time correlation function is measured directly. Dilute solutions of deuterated polystyrene (PSD) and deuterated polytetrahydrofuran (PTDF) in carbon disulphide, and of their hydrogeneous counterparts (PSH and PTHF respectively) in deuterated benzene were investigated in the range 0.027 A -1 -1 , at 30 0 C. (orig./FKS)

  1. Foaming behaviour of polymer-surfactant solutions

    International Nuclear Information System (INIS)

    Cervantes-MartInez, Alfredo; Maldonado, Amir

    2007-01-01

    We study the effect of a non-ionic amphiphilic polymer (PEG-100 stearate also called Myrj 59) on the foaming behaviour of aqueous solutions of an anionic surfactant (sodium dodecyl sulfate or SDS). The SDS concentration was kept fixed while the Myrj 59 concentration was varied. Measurements of foamability, surface tension and electrical conductivity were carried out. The results show two opposite effects depending on the polymer concentration: foamability is higher when the Myrj 59 concentration is low; however, it decreases considerably when the polymer concentration is increased. This behaviour is due to the polymer adsorption at the air/liquid interface at lower polymer concentrations, and to the formation of a polymer-surfactant complex in the bulk at higher concentrations. The results are confirmed by surface tension and electrical conductivity measurements, which are interpreted in terms of the microstructure of the polymer-surfactant solutions. The observed behaviour is due to the amphiphilic nature of the studied polymer. The increased hydrophobicity of Myrj 59, compared to that of water-soluble polymers like PEG or PEO, increases its 'reactivity' towards SDS, i.e. the strength of its interaction with this anionic surfactant. Our results show that hydrophobically modified polymers have potential applications as additives in order to control the foaming properties of surfactant solutions

  2. Effects of Intercalation on the Hole Mobility of Amorphous Semiconducting Polymer Blends

    KAUST Repository

    Cates, Nichole C.

    2010-06-08

    Fullerenes have been shown to intercalate between the side chains of many crystalline and semicrystalline polymers and to affect the properties of polymer:fullerene bulk heterojunction solar cells. Here we present the first in-depth study of intercalation in an amorphous polymer. We study blends of the widely studied amorphous polymer poly(2-methoxy-5-(3studied amorphous polymer poly(,7·studied amorphous polymer poly(-dimethyloctyloxy)-p-phenylene vinylene) (MDMO-PPV) with a variety of molecules using photoluminescence measurements, scanning electron microscopy, and space-charge limited current mobility measurements. The blends with elevated hole mobilities exhibit complete photoluminescence quenching and show no phase separation in a scanning electron microscope. We conclude that intercalation occurs in MDMO-PPV:fullerene blends and is responsible for the increase in the MDMO-PPV hole mobility by several orders of magnitude when it is blended with fullerenes, despite the dilution of the hole-conducting polymer with an electron acceptor. © 2010 American Chemical Society.

  3. Structuring of polymer solutions upon solvent evaporation

    NARCIS (Netherlands)

    Schaefer, C.; van der Schoot, P.|info:eu-repo/dai/nl/102140618; Michels, J. J.

    2015-01-01

    The morphology of solution-cast, phase-separated polymers becomes finer with increasing solvent evaporation rate. We address this observation theoretically for a model polymer where demixing is induced by steady solvent evaporation. In contrast to what is the case for a classical, thermal quench

  4. Modeling the Coupled Chemo-Thermo-Mechanical Behavior of Amorphous Polymer Networks.

    Energy Technology Data Exchange (ETDEWEB)

    Zimmerman, Jonathan A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Nguyen, Thao D. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Xiao, Rui [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2015-02-01

    Amorphous polymers exhibit a rich landscape of time-dependent behavior including viscoelasticity, structural relaxation, and viscoplasticity. These time-dependent mechanisms can be exploited to achieve shape-memory behavior, which allows the material to store a programmed deformed shape indefinitely and to recover entirely the undeformed shape in response to specific environmental stimulus. The shape-memory performance of amorphous polymers depends on the coordination of multiple physical mechanisms, and considerable opportunities exist to tailor the polymer structure and shape-memory programming procedure to achieve the desired performance. The goal of this project was to use a combination of theoretical, numerical and experimental methods to investigate the effect of shape memory programming, thermo-mechanical properties, and physical and environmental aging on the shape memory performance. Physical and environmental aging occurs during storage and through exposure to solvents, such as water, and can significantly alter the viscoelastic behavior and shape memory behavior of amorphous polymers. This project – executed primarily by Professor Thao Nguyen and Graduate Student Rui Xiao at Johns Hopkins University in support of a DOE/NNSA Presidential Early Career Award in Science and Engineering (PECASE) – developed a theoretical framework for chemothermo- mechanical behavior of amorphous polymers to model the effects of physical aging and solvent-induced environmental factors on their thermoviscoelastic behavior.

  5. Hot Melt Extrusion and Spray Drying of Co-amorphous Indomethacin-Arginine With Polymers.

    Science.gov (United States)

    Lenz, Elisabeth; Löbmann, Korbinian; Rades, Thomas; Knop, Klaus; Kleinebudde, Peter

    2017-01-01

    Co-amorphous drug-amino acid systems have gained growing interest as an alternative to common amorphous formulations which contain polymers as stabilizers. Several preparation methods have recently been investigated, including vibrational ball milling on a laboratory scale or spray drying in a larger scale. In this study, the feasibility of hot melt extrusion for continuous manufacturing of co-amorphous drug-amino acid formulations was examined, challenging the fact that amino acids melt with degradation at high temperatures. Furthermore, the need for an addition of a polymer in this process was evaluated. After a polymer screening via the solvent evaporation method, co-amorphous indomethacin-arginine was prepared by a melting-solvent extrusion process without and with copovidone. The obtained products were characterized with respect to their solid-state properties, non-sink dissolution behavior, and stability. Results were compared to those of spray-dried formulations with the same compositions and to spray-dried indomethacin-copovidone. Overall, stable co-amorphous systems could be prepared by extrusion without or with copovidone, which exhibited comparable molecular interaction properties to the respective spray-dried products, while phase separation was detected by differential scanning calorimetry in several cases. The formulations containing indomethacin in combination with arginine and copovidone showed enhanced dissolution behavior over the formulations with only copovidone or arginine. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  6. Physical stability of amorphous acetanilide derivatives improved by polymer excipients.

    Science.gov (United States)

    Miyazaki, Tamaki; Yoshioka, Sumie; Aso, Yukio

    2006-08-01

    Crystallization rates of drug-polymer solid dispersions prepared with acetaminophen (ACA) and p-aminoacetanilide (AAA) as model drugs, and polyvinylpyrrolidone and polyacrylic acid (PAA) as model polymers were measured in order to further examine the significance of drug-polymer interactions. The crystallization of AAA and ACA was inhibited by mixing those polymers. The most effective inhibition was observed with solid dispersions of AAA and PAA. The combination of AAA and PAA showed a markedly longer enthalpy relaxation time relative to drug alone as well as a higher T(g) than predicted by the Gordon-Taylor equation, indicating the existence of a strong interaction between the two components. These observations suggest that crystallization is effectively inhibited by combinations of drug and polymer that show a strong intermolecular interaction due to proton transfer between acidic and basic functional groups.

  7. Amorphous/crystal and polymer/filler interphases in biocomposites from poly(butylene succinate)

    Energy Technology Data Exchange (ETDEWEB)

    Signori, Francesca [Consiglio Nazionale delle Ricerche - Istituto per i Processi Chimico-Fisici (CNR-IPCF), Via G. Moruzzi 1, I-56124 Pisa (Italy); Pelagaggi, Martina [Universita di Pisa - Dipartimento di Chimica e Chimica Industriale, Via Risorgimento 35, I-56126 Pisa (Italy); Bronco, Simona [Consiglio Nazionale delle Ricerche - Istituto per i Processi Chimico-Fisici (CNR-IPCF), Via G. Moruzzi 1, I-56124 Pisa (Italy); Righetti, Maria Cristina, E-mail: righetti@ipcf.cnr.it [Consiglio Nazionale delle Ricerche - Istituto per i Processi Chimico-Fisici (CNR-IPCF), Via G. Moruzzi 1, I-56124 Pisa (Italy)

    2012-09-10

    Highlights: Black-Right-Pointing-Pointer The existence of intermolecular interactions between poly(butylene succinate) and hemp fibres was proved from specific heat capacities data. Black-Right-Pointing-Pointer Different degrees of mobility of the poly(butylene succinate) amorphous segments were evidenced at the amorphous/crystal interphase. Black-Right-Pointing-Pointer Devitrification of the rigid amorphous fraction in poly(butylene succinate) was found to occur before and simultaneously with the fusion. - Abstract: Poly(butylene succinate)-hemp composites (PBS-hemp), with hemp content in the range 0-40 wt.%, were prepared in the melt and characterized. This paper focuses on the detailed analysis of the thermal behaviour of the PBS-hemp composites, investigated by differential scanning calorimetry (DSC), to enlighten the polymer/fibre interphase features. The occurrence of specific intermolecular interactions between PBS and hemp was assessed from specific heat capacity data. Different degrees of mobility of the PBS amorphous segments were found at the amorphous/crystal interphases. A broadening of the bulk glass transition was observed, and attributed to the presence of polymer segments slightly constrained. Moreover, a rigid amorphous fraction that devitrifies at temperatures higher than the bulk glass transition, partly before the melting region and partly simultaneously with the fusion, was observed and quantified, and attributed to the presence of major constraints probably occurring in geometrically restricted areas.

  8. The still unknown azobenzene - Wavelength dependent photoanisotropy in amorphous azobenzene polymers

    DEFF Research Database (Denmark)

    Ramanujam, P.S.; Jensen, Ole Bjarlin; Tidemand-Lichtenberg, Peter

    2013-01-01

    We demonstrate a new type of anisotropy in thin films of amorphous azobenzene polymers induced between 570 and 633 nm, where the absorbance in the film is on the order of 0.05. The anisotropy has a pronounced radial contribution. This observation points to an additional mechanism for the alignment...

  9. Transport of organic solutes through amorphous teflon AF films.

    Science.gov (United States)

    Zhao, Hong; Zhang, Jie; Wu, Nianqiang; Zhang, Xu; Crowley, Katie; Weber, Stephen G

    2005-11-02

    Fluorous media have great potential for selective extraction (e.g., as applied to organic synthesis). Fluorous polymer films would have significant advantages in fluorous separations. Stable films of Teflon AF 2400 were cast from solution. Films appear defect-free (SEM; AFM). Rigid aromatic solutes are transported (from chloroform solution to chloroform receiving phase) in a size-dependent manner (log permeability is proportional to -0.0067 times critical volume). Benzene's permeability is about 2 orders of magnitude higher than in comparable gas-phase experiments. The films show selectivity for fluorinated solutes in comparison to the hydrogen-containing control. Transport rates are dependent on the solvent making up the source and receiving phases. The effect of solvent is, interestingly, not due to changes in partition ratio, but rather it is due to changes in the solute diffusion coefficient in the film. Solvents plasticize the films. A less volatile compound, -COOH-terminated poly(hexafluoropropylene oxide) (4), plasticizes the films (T(g) = -40 degrees C). Permeabilities are decreased in comparison to 4-free films apparently because of decreased diffusivity of solutes. The slope of dependence of log permeability on critical volume is not changed, however.

  10. Structure and dynamics of amorphous polymers: computer simulations compared to experiment and theory

    International Nuclear Information System (INIS)

    Paul, Wolfgang; Smith, Grant D

    2004-01-01

    This contribution considers recent developments in the computer modelling of amorphous polymeric materials. Progress in our capabilities to build models for the computer simulation of polymers from the detailed atomistic scale up to coarse-grained mesoscopic models, together with the ever-improving performance of computers, have led to important insights from computer simulations into the structural and dynamic properties of amorphous polymers. Structurally, chain connectivity introduces a range of length scales from that of the chemical bond to the radius of gyration of the polymer chain covering 2-4 orders of magnitude. Dynamically, this range of length scales translates into an even larger range of time scales observable in relaxation processes in amorphous polymers ranging from about 10 -13 to 10 -3 s or even to 10 3 s when glass dynamics is concerned. There is currently no single simulation technique that is able to describe all these length and time scales efficiently. On large length and time scales basic topology and entropy become the governing properties and this fact can be exploited using computer simulations of coarse-grained polymer models to study universal aspects of the structure and dynamics of amorphous polymers. On the largest length and time scales chain connectivity is the dominating factor leading to the strong increase in longest relaxation times described within the reptation theory of polymer melt dynamics. Recently, many of the universal aspects of this behaviour have been further elucidated by computer simulations of coarse-grained polymer models. On short length scales the detailed chemistry and energetics of the polymer are important, and one has to be able to capture them correctly using chemically realistic modelling of specific polymers, even when the aim is to extract generic physical behaviour exhibited by the specific chemistry. Detailed studies of chemically realistic models highlight the central importance of torsional dynamics

  11. Picot-Benoit Effect in Polymer Solutions

    Science.gov (United States)

    Beaucage, Gregory; Sukumaran, Sathish; Ilavsky, Jan

    2003-03-01

    SAXS from polymers in solution is well described at intermediate (q = 0.01-0.1 Å-1) scattering vectors by scaling theory which predicts three regimes in concentration: dilute, semi-dilute and concentrated [1-3]. A persistent problem is the appearance of excess scattering at low-q, q molecular weight dependence for these fluctuations in the dilute and semi-dilute regimes. The later is unexpected since above c* scaling theory predicts no M dependencies due to screening [1-3]. The literature associates PB features with semi-dilute and concentrated solutions, yet we have observed excess scattering even in dilute solutions of polystyrene in cyclopentane. 1) de Gennes P-G, Scaling Concepts in Polymer Physics, 1979. 2) Strobl G, The Physics of Polymers, Berlin 1997. 3) Doi M, Introduction to Polymer Physics, Oxford 1997. 4) Benoit H, Picot C Pure Appl. Chem. 12 545 (1966). 5) Benoit H, Picot C Pure Appl. Chem. 12 1271 (1966). 6) Xie Y, et al. Physica A 232 94 (1996). 7) Korberstein JT, et al. Polymer 26 673 (1985). 8) Morfin I, et al. Macromolecules 32 7208 (1999). 9) Blanco CM, et al. Langmuir 16 8585 (2000).

  12. Spin coating of an evaporating polymer solution

    KAUST Repository

    Münch, Andreas; Please, Colin P.; Wagner, Barbara

    2011-01-01

    and centrifugal forces and evaporation of the solvent. In the model both the diffusivity of the solvent in the polymer and the viscosity of the mixture are very rapidly varying functions of the solvent mass fraction. Guided by numerical solutions an asymptotic

  13. A Polymer "Pollution Solution" Classroom Activity.

    Science.gov (United States)

    Helser, Terry L.

    1996-01-01

    Explains an approach to presenting polymer chemistry to nonmajors that employs polystyrene foam, foam peanuts made from water soluble starch, and water soluble plastic bags. Students are presented with a pollution scenario and are guided to the discovery of solutions. (DDR)

  14. Polarization of positronium in amorphous polar polymers: A case study

    Energy Technology Data Exchange (ETDEWEB)

    Consolati, G., E-mail: giovanni.consolati@polimi.it; Quasso, F. [Department of Aerospace Science and Technology, Politecnico di Milano, via La Masa, 34, Milano 20156 (Italy)

    2013-11-28

    The features of positronium in an amorphous copolymer (polyvinyl acetate-crotonic acid) in a range of temperatures including the glass transition were investigated by means of positron annihilation lifetime spectroscopy. In particular, para-positronium lifetime was found to be longer than in a vacuum and to decrease with the temperature. This was attributed to the electron density at the positron (contact density), which is lower than in vacuo due to the presence of polar groups in the copolymer. A three quantum yield experiment confirmed the lifetime results.

  15. Solution growth of microcrystalline silicon on amorphous substrates

    Energy Technology Data Exchange (ETDEWEB)

    Heimburger, Robert

    2010-07-05

    This work deals with low-temperature solution growth of micro-crystalline silicon on glass. The task is motivated by the application in low-cost solar cells. As glass is an amorphous material, conventional epitaxy is not applicable. Therefore, growth is conducted in a two-step process. The first step aims at the spatial arrangement of silicon seed crystals on conductive coated glass substrates, which is realized by means of vapor-liquid-solid processing using indium as the solvent. Seed crystals are afterwards enlarged by applying a specially developed steady-state solution growth apparatus. This laboratory prototype mainly consists of a vertical stack of a silicon feeding source and the solvent (indium). The growth substrate can be dipped into the solution from the top. The system can be heated to a temperature below the softening point of the utilized glass substrate. A temperature gradient between feeding source and growth substrate promotes both, supersaturation and material transport by solvent convection. This setup offers advantages over conventional liquid phase epitaxy at low temperatures in terms of achievable layer thickness and required growth times. The need for convective solute transport to gain the desired thickness of at least 50 {mu}m is emphasized by equilibrium calculations in the binary system indium-silicon. Material transport and supersaturation conditions inside the utilized solution growth crucible are analyzed. It results that the solute can be transported from the lower feeding source to the growth substrate by applying an appropriate heating regime. These findings are interpreted by means of a hydrodynamic analysis of fluid flow and supporting FEM simulation. To ensure thermodynamic stability of all materials involved during steady-state solution growth, the ternary phase equilibrium between molybdenum, indium and silicon at 600 C was considered. Based on the obtained results, the use of molybdenum disilicide as conductive coating

  16. On electronic structure of polymer-derived amorphous silicon carbide ceramics

    Science.gov (United States)

    Wang, Kewei; Li, Xuqin; Ma, Baisheng; Wang, Yiguang; Zhang, Ligong; An, Linan

    2014-06-01

    The electronic structure of polymer-derived amorphous silicon carbide ceramics was studied by combining measurements of temperature-dependent conductivity and optical absorption. By comparing the experimental results to theoretical models, electronic structure was constructed for a carbon-rich amorphous silicon carbide, which revealed several unique features, such as deep defect energy level, wide band-tail band, and overlap between the band-tail band and defect level. These unique features were discussed in terms of the microstructure of the material and used to explain the electric behavior.

  17. Hot Melt Extrusion and Spray Drying of Co-amorphous Indomethacin-Arginine With Polymers

    DEFF Research Database (Denmark)

    Lenz, Elisabeth; Löbmann, Korbinian; Rades, Thomas

    2017-01-01

    Co-amorphous drug-amino acid systems have gained growing interest as an alternative to common amorphous formulations which contain polymers as stabilizers. Several preparation methods have recently been investigated, including vibrational ball milling on a laboratory scale or spray drying......, and stability. Results were compared to those of spray-dried formulations with the same compositions and to spray-dried indomethacin-copovidone. Overall, stable co-amorphous systems could be prepared by extrusion without or with copovidone, which exhibited comparable molecular interaction properties...... to the respective spray-dried products, while phase separation was detected by differential scanning calorimetry in several cases. The formulations containing indomethacin in combination with arginine and copovidone showed enhanced dissolution behavior over the formulations with only copovidone or arginine....

  18. Small angle neutron scattering by polymer solutions

    International Nuclear Information System (INIS)

    Farnoux, B.; Jannink, G.

    1980-08-01

    Small angle neutron scattering is an experimental technique introduced since about 10 years for the observation of the polymer conformation in all the concentration range from dilute solution to the melt. After a brief recall of the elementary relations between scattering amplitude, index of refraction and scattered intensity, two concepts related to this last quantity (the contrast and the pair correlation function) are discussed in details

  19. Spin coating of an evaporating polymer solution

    KAUST Repository

    Münch, Andreas

    2011-01-01

    We consider a mathematical model of spin coating of a single polymer blended in a solvent. The model describes the one-dimensional development of a thin layer of the mixture as the layer thins due to flow created by a balance of viscous forces and centrifugal forces and evaporation of the solvent. In the model both the diffusivity of the solvent in the polymer and the viscosity of the mixture are very rapidly varying functions of the solvent mass fraction. Guided by numerical solutions an asymptotic analysis reveals a number of different possible behaviours of the thinning layer dependent on the nondimensional parameters describing the system. The main practical interest is in controlling the appearance and development of a "skin" on the polymer where the solvent concentration reduces rapidly on the outer surface leaving the bulk of the layer still with high concentrations of solvent. In practice, a fast and uniform drying of the film is required. The critical parameters controlling this behaviour are found to be the ratio of the diffusion to advection time scales ε, the ratio of the evaporation to advection time scales δ and the ratio of the diffusivity of the pure polymer and the initial mixture exp(-1/γ). In particular, our analysis shows that for very small evaporation with δ

  20. Polymer solution phase separation: Microgravity simulation

    Science.gov (United States)

    Cerny, Lawrence C.; Sutter, James K.

    1989-01-01

    In many multicomponent systems, a transition from a single phase of uniform composition to a multiphase state with separated regions of different composition can be induced by changes in temperature and shear. The density difference between the phase and thermal and/or shear gradients within the system results in buoyancy driven convection. These differences affect kinetics of the phase separation if the system has a sufficiently low viscosity. This investigation presents more preliminary developments of a theoretical model in order to describe effects of the buoyancy driven convection in phase separation kinetics. Polymer solutions were employed as model systems because of the ease with which density differences can be systematically varied and because of the importance of phase separation in the processing and properties of polymeric materials. The results indicate that the kinetics of the phase separation can be performed viscometrically using laser light scattering as a principle means of following the process quantitatively. Isopycnic polymer solutions were used to determine the viscosity and density difference limits for polymer phase separation.

  1. 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.

  2. Evaluation of the amorphous content of lactose by solution calorimetry and Raman spectroscopy.

    Science.gov (United States)

    Katainen, Erja; Niemelä, Pentti; Harjunen, Päivi; Suhonen, Janne; Järvinen, Kristiina

    2005-11-15

    Solution calorimetry can be used to determine the amorphous content of a compound when the solubility and dissolution rate of the compound in the chosen solvent are reasonably high. Sometimes, it can be difficult find a solvent in which a sample is freely soluble. The present study evaluated the use of solution calorimetry for the assessment of the amorphous content of a sample that is poorly soluble in a solvent. Physical mixtures of lactose and spray-dried lactose samples (the amorphous content varied from 0 to 100%) were analyzed by a solution calorimeter and the results were compared with Raman spectroscopy determinations. The heat of solvation of the samples was determined by solution calorimetry in organic solvents MeOH, EtOH, ACN, THF, acetone (400mg sample/100ml solvent). Lactose is virtually insoluble in ACN, THF and acetone and very slightly soluble in EtOH and MeOH. The amorphous content of the samples could not be determined by solution calorimetry in EtOH, ACN, THF or acetone. However, an excellent correlation was observed between the heat of solvation and the amorphous content of the samples in MeOH. Furthermore, the heat of solvation values of the samples in MeOH showed a linear correlation with the Raman quantifications. Therefore, our results demonstrate that solution calorimetry may represent a rapid and simple method for determining the amorphous content also in samples that are not freely soluble in the solvent.

  3. Constant force extensional rheometry of polymer solutions

    DEFF Research Database (Denmark)

    Szabo, Peter; McKinley, Gareth H.; Clasen, Christian

    2012-01-01

    We revisit the rapid stretching of a liquid filament under the action of a constant imposed tensile force, a problem which was first considered by Matta and Tytus [J. Non-Newton. Fluid Mech. 35 (1990) 215–229]. A liquid bridge formed from a viscous Newtonian fluid or from a dilute polymer solution...... is first established between two cylindrical disks. The upper disk is held fixed and may be connected to a force transducer while the lower cylinder falls due to gravity. By varying the mass of the falling cylinder and measuring its resulting acceleration, the viscoelastic nature of the elongating fluid...... filament can be probed. In particular, we show that with this constant force pull (CFP) technique it is possible to readily impose very large material strains and strain rates so that the maximum extensibility of the polymer molecules may be quantified. This unique characteristic of the experiment...

  4. The Soft-Confined Method for Creating Molecular Models of Amorphous Polymer Surfaces

    KAUST Repository

    Liu, Hongyi; Li, Yan; Krause, Wendy E.; Rojas, Orlando J.; Pasquinelli, Melissa A.

    2012-01-01

    The goal of this work was to use molecular dynamics (MD) simulations to build amorphous surface layers of polypropylene (PP) and cellulose and to inspect their physical and interfacial properties. A new method to produce molecular models for these surfaces was developed, which involved the use of a "soft" confining layer comprised of a xenon crystal. This method compacts the polymers into a density distribution and a degree of molecular surface roughness that corresponds well to experimental values. In addition, calculated properties such as density, cohesive energy density, coefficient of thermal expansion, and the surface energy agree with experimental values and thus validate the use of soft confining layers. The method can be applied to polymers with a linear backbone such as PP as well as those whose backbones contain rings, such as cellulose. The developed PP and cellulose surfaces were characterized by their interactions with water. It was found that a water nanodroplet spreads on the amorphous cellulose surfaces, but there was no significant change in the dimension of the droplet on the PP surface; the resulting MD water contact angles on PP and amorphous cellulose surfaces were determined to be 106 and 33°, respectively. © 2012 American Chemical Society.

  5. The Soft-Confined Method for Creating Molecular Models of Amorphous Polymer Surfaces

    KAUST Repository

    Liu, Hongyi

    2012-02-09

    The goal of this work was to use molecular dynamics (MD) simulations to build amorphous surface layers of polypropylene (PP) and cellulose and to inspect their physical and interfacial properties. A new method to produce molecular models for these surfaces was developed, which involved the use of a "soft" confining layer comprised of a xenon crystal. This method compacts the polymers into a density distribution and a degree of molecular surface roughness that corresponds well to experimental values. In addition, calculated properties such as density, cohesive energy density, coefficient of thermal expansion, and the surface energy agree with experimental values and thus validate the use of soft confining layers. The method can be applied to polymers with a linear backbone such as PP as well as those whose backbones contain rings, such as cellulose. The developed PP and cellulose surfaces were characterized by their interactions with water. It was found that a water nanodroplet spreads on the amorphous cellulose surfaces, but there was no significant change in the dimension of the droplet on the PP surface; the resulting MD water contact angles on PP and amorphous cellulose surfaces were determined to be 106 and 33°, respectively. © 2012 American Chemical Society.

  6. Structure-Property Relationships in Polymer Derived Amorphous/Nano-Crystalline Silicon Carbide for Nuclear Applications

    International Nuclear Information System (INIS)

    Zunjarrao, Suraj C.; Singh, Abhishek K.; Singh, Raman P.

    2006-01-01

    Silicon carbide (SiC) is a promising candidate for several applications in nuclear reactors owing to its high thermal conductivity, high melting temperature, good chemical stability, and resistance to swelling under heavy ion bombardment. However, fabricating SiC by traditional powder processing route generally requires very high temperatures for pressureless sintering. Polymer derived ceramic materials offer unique advantages such as ability to fabricate net shaped components, incorporate reinforcements and relatively low processing temperatures. Furthermore, for SiC based ceramics fabricated using polymer infiltration process (PIP), the microstructure can be tailored by controlling the processing parameters, to get an amorphous, nanocrystalline or crystalline SiC. In this work, fabrication of polymer derived amorphous and nano-grained SiC is presented and its application as an in-core material is explored. Monolithic SiC samples are fabricated by controlled pyrolysis of allyl-hydrido-poly-carbo-silane (AHPCS) under inert atmosphere. Chemical changes, phase transformations and microstructural changes occurring during the pyrolysis process are studied as a function of the processing temperature. Polymer cross-linking and polymer to ceramic conversion is studied using infrared spectroscopy (FTIR). Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) are performed to monitor the mass loss and phase change as a function of temperature. X-ray diffraction studies are done to study the intermediate phases and microstructural changes. Variation in density is carefully monitored as a function of processing temperature. Owing to shrinkage and gas evolution during pyrolysis, precursor derived ceramics are inherently porous and composite fabrication typically involves repeated cycles of polymer re-infiltration and pyrolysis. However, there is a limit to the densification that can be achieved by this method and porosity in the final materials presents

  7. Solid solution and amorphous phase in Ti–Nb–Ta–Mn systems synthesized by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar, C., E-mail: claudio.aguilar@usm.cl [Departamento de Ingeniería Metalúrgica y Materiales, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile); Guzman, P. [Departamento de Ingeniería Metalúrgica y Materiales, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile); Lascano, S. [Departamento de Ingeniería Mecánica, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile); Parra, C. [Departamento de Física, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile); Bejar, L. [Instituto de Investigaciones Metalúrgicas, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, Morelia C.P. 58000, Michoacán (Mexico); Medina, A. [Facultad de Ingeniería Mecánica, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, C.P. 58000, Michoacán (Mexico); Guzman, D. [Departamento de Metalurgia, Universidad de Atacama, Av. España 485, Copiapó (Chile)

    2016-06-15

    This work discusses the formation of Ti–30Nb–13Ta–xMn (x: 2, 4 and 6 wt%) solid solution by mechanical alloying using a shaker mill. A solid solution was formed after 15 h of milling and an amorphous phase was formed after 30 h of milling, according to X-ray diffraction results. Disappearance of strongest X-ray diffraction peaks of Nb, Ta and Mn indicated the formation of solid solution, while, X-ray diffraction patterns of powders milled for 30 h showed an amorphous hump with crystalline peaks in the angular range of 35–45° in 2θ. TEM image analysis showed the presence of nanocrystalline intermetallic compounds embedded in an amorphous matrix. Mn{sub 2}Ti, MnTi and NbTi{sub 4} intermetallic compounds were detected and revealed crystallites with size ranging from 3 to 20 nm. The Gibbs free energy for the formation of solid solution and amorphous phase of three ternary systems (Ti–Nb–Ta, Ti–Nb–Mn and Ti–Ta–Mn) was calculated using extended Miedema's model. Experimental and thermodynamic data confirmed that solid solution was first formed in the alloy with 6wt% Mn followed by the formation of an amorphous phase as milling time increases. The presence of Mn promoted the formation of amorphous phase because the atomic radius difference between Mn with Ti, Nb and Ta. - Highlights: • Thermodynamics analysis of extension of solid solution of the Ti–Nb–Ta–Mn system. • Formation of amorphous phase and intermetallic compounds were observed. • Nanocrystalline intermetallic compounds were formed with the sizes between 3 and 20 nm.

  8. Polarization holograms in a bifunctional amorphous polymer exhibiting equal values of photoinduced linear and circular birefringences.

    Science.gov (United States)

    Provenzano, Clementina; Pagliusi, Pasquale; Cipparrone, Gabriella; Royes, Jorge; Piñol, Milagros; Oriol, Luis

    2014-10-09

    Light-controlled molecular alignment is a flexible and useful strategy introducing novelty in the fields of mechanics, self-organized structuring, mass transport, optics, and photonics and addressing the development of smart optical devices. Azobenzene-containing polymers are well-known photocontrollable materials with large and reversible photoinduced optical anisotropies. The vectorial holography applied to these materials enables peculiar optical devices whose properties strongly depend on the relative values of the photoinduced birefringences. Here is reported a polarization holographic recording based on the interference of two waves with orthogonal linear polarization on a bifunctional amorphous polymer that, exceptionally, exhibits equal values of linear and circular birefringence. The peculiar photoresponse of the material coupled with the holographic technique demonstrates an optical device capable of decomposing the light into a set of orthogonally polarized linear components. The holographic structures are theoretically described by the Jones matrices method and experimentally investigated.

  9. Experimental and modelling studies of the shape memory properties of amorphous polymer network composites

    International Nuclear Information System (INIS)

    Arrieta, J S; Diani, J; Gilormini, P

    2014-01-01

    Shape memory polymer composites (SMPCs) have become an important way to leverage improvements in the development of applications featuring shape memory polymers (SMPs). In this study, an amorphous SMP matrix has been filled with different types of reinforcements. An experimental set of results is presented and then compared to three-dimensional (3D) finite-element simulations. Thermomechanical shape memory cycles were performed in uniaxial tension. The fillers effect was studied in stress-free and constrained-strain recoveries. Experimental observations indicate complete shape recovery and put in evidence the increased sensitivity of constrained length stress recoveries to the heating ramp on the tested composites. The simulations reproduced a simplified periodic reinforced composite and used a model for the matrix material that has been previously tested on regular SMPs. The latter combines viscoelasticity at finite strain and time-temperature superposition. The simulations easily allow representation of the recovery properties of a reinforced SMP. (paper)

  10. On the Mass Fractal Character of Si-Based Structural Networks in Amorphous Polymer Derived Ceramics

    Directory of Open Access Journals (Sweden)

    Sabyasachi Sen

    2015-03-01

    Full Text Available The intermediate-range packing of SiNxC4−x (0 ≤ x ≤ 4 tetrahedra in polysilycarbodiimide and polysilazane-derived amorphous SiCN ceramics is investigated using 29Si spin-lattice relaxation nuclear magnetic resonance (SLR NMR spectroscopy. The SiCN network in the polysilylcarbodiimide-derived ceramic consists predominantly of SiN4 tetrahedra that are characterized by a 3-dimensional spatial distribution signifying compact packing of such units to form amorphous Si3N4 clusters. On the other hand, the SiCN network of the polysilazane-derived ceramic is characterized by mixed bonded SiNxC4−x tetrahedra that are inefficiently packed with a mass fractal dimension of Df ~2.5 that is significantly lower than the embedding Euclidean dimension (D = 3. This result unequivocally confirms the hypothesis that the presence of dissimilar atoms, namely, 4-coordinated C and 3-coordinated N, in the nearest neighbor environment of Si along with some exclusion in connectivity between SiCxN4−x tetrahedra with widely different N:C ratios and the absence of bonding between C and N result in steric hindrance to an efficient packing of these structural units. It is noted that similar inefficiencies in packing are observed in polymer-derived amorphous SiOC ceramics as well as in proteins and binary hard sphere systems.

  11. On the Mass Fractal Character of Si-Based Structural Networks in Amorphous Polymer Derived Ceramics.

    Science.gov (United States)

    Sen, Sabyasachi; Widgeon, Scarlett

    2015-03-17

    The intermediate-range packing of SiN x C 4- x (0 ≤ x ≤ 4) tetrahedra in polysilycarbodiimide and polysilazane-derived amorphous SiCN ceramics is investigated using 29 Si spin-lattice relaxation nuclear magnetic resonance (SLR NMR) spectroscopy. The SiCN network in the polysilylcarbodiimide-derived ceramic consists predominantly of SiN₄ tetrahedra that are characterized by a 3-dimensional spatial distribution signifying compact packing of such units to form amorphous Si₃N₄ clusters. On the other hand, the SiCN network of the polysilazane-derived ceramic is characterized by mixed bonded SiN x C 4- x tetrahedra that are inefficiently packed with a mass fractal dimension of D f ~2.5 that is significantly lower than the embedding Euclidean dimension ( D = 3). This result unequivocally confirms the hypothesis that the presence of dissimilar atoms, namely, 4-coordinated C and 3-coordinated N, in the nearest neighbor environment of Si along with some exclusion in connectivity between SiC x N 4- x tetrahedra with widely different N:C ratios and the absence of bonding between C and N result in steric hindrance to an efficient packing of these structural units. It is noted that similar inefficiencies in packing are observed in polymer-derived amorphous SiOC ceramics as well as in proteins and binary hard sphere systems.

  12. Corrosion resistance of amorphous and crystalline Pd40Ni40P20 alloys in aqueous solutions

    DEFF Research Database (Denmark)

    Wu, Y.F.; Chiang, Wen-Chi; Chu, J.

    2006-01-01

    The corrosion behaviors of amorphous and crystalline Pd40Ni40P20 alloys in various aqueous solutions are reported in this paper. The corrosion resistance of crystalline (annealed) Pd40Ni40P20 is better than that of amorphous Pd40Ni40P20 in various corrosive solutions, due to crystalline Pd40Ni40P20...... and mainly consists of inert Pd5P2, NI3P, Ni2Pd2P and noble Pd phases. These inert and noble properties result in a higher corrosion resistance in crystalline Pd40Ni40P20....

  13. Optimising Drug Solubilisation in Amorphous Polymer Dispersions: Rational Selection of Hot-melt Extrusion Processing Parameters.

    Science.gov (United States)

    Li, Shu; Tian, Yiwei; Jones, David S; Andrews, Gavin P

    2016-02-01

    The aim of this article was to construct a T-ϕ phase diagram for a model drug (FD) and amorphous polymer (Eudragit® EPO) and to use this information to understand the impact of how temperature-composition coordinates influenced the final properties of the extrudate. Defining process boundaries and understanding drug solubility in polymeric carriers is of utmost importance and will help in the successful manufacture of new delivery platforms for BCS class II drugs. Physically mixed felodipine (FD)-Eudragit(®) EPO (EPO) binary mixtures with pre-determined weight fractions were analysed using DSC to measure the endset of melting and glass transition temperature. Extrudates of 10 wt% FD-EPO were processed using temperatures (110°C, 126°C, 140°C and 150°C) selected from the temperature-composition (T-ϕ) phase diagrams and processing screw speed of 20, 100 and 200rpm. Extrudates were characterised using powder X-ray diffraction (PXRD), optical, polarised light and Raman microscopy. To ensure formation of a binary amorphous drug dispersion (ADD) at a specific composition, HME processing temperatures should at least be equal to, or exceed, the corresponding temperature value on the liquid-solid curve in a F-H T-ϕ phase diagram. If extruded between the spinodal and liquid-solid curve, the lack of thermodynamic forces to attain complete drug amorphisation may be compensated for through the use of an increased screw speed. Constructing F-H T-ϕ phase diagrams are valuable not only in the understanding drug-polymer miscibility behaviour but also in rationalising the selection of important processing parameters for HME to ensure miscibility of drug and polymer.

  14. Formation of soft magnetic high entropy amorphous alloys composites containing in situ solid solution phase

    Science.gov (United States)

    Wei, Ran; Sun, Huan; Chen, Chen; Tao, Juan; Li, Fushan

    2018-03-01

    Fe-Co-Ni-Si-B high entropy amorphous alloys composites (HEAACs), which containing high entropy solid solution phase in amorphous matrix, show good soft magnetic properties and bending ductility even in optimal annealed state, were successfully developed by melt spinning method. The crystallization phase of the HEAACs is solid solution phase with body centered cubic (BCC) structure instead of brittle intermetallic phase. In addition, the BCC phase can transformed into face centered cubic (FCC) phase with temperature rise. Accordingly, Fe-Co-Ni-Si-B high entropy alloys (HEAs) with FCC structure and a small amount of BCC phase was prepared by copper mold casting method. The HEAs exhibit high yield strength (about 1200 MPa) and good plastic strain (about 18%). Meanwhile, soft magnetic characteristics of the HEAs are largely reserved from HEAACs. This work provides a new strategy to overcome the annealing induced brittleness of amorphous alloys and design new advanced materials with excellent comprehensive properties.

  15. Performance of dielectric nanocomposites: matrix-free, hairy nanoparticle assemblies and amorphous polymer-nanoparticle blends.

    Science.gov (United States)

    Grabowski, Christopher A; Koerner, Hilmar; Meth, Jeffrey S; Dang, Alei; Hui, Chin Ming; Matyjaszewski, Krzysztof; Bockstaller, Michael R; Durstock, Michael F; Vaia, Richard A

    2014-12-10

    Demands to increase the stored energy density of electrostatic capacitors have spurred the development of materials with enhanced dielectric breakdown, improved permittivity, and reduced dielectric loss. Polymer nanocomposites (PNCs), consisting of a blend of amorphous polymer and dielectric nanofillers, have been studied intensely to satisfy these goals; however, nanoparticle aggregates, field localization due to dielectric mismatch between particle and matrix, and the poorly understood role of interface compatibilization have challenged progress. To expand the understanding of the inter-relation between these factors and, thus, enable rational optimization of low and high contrast PNC dielectrics, we compare the dielectric performance of matrix-free hairy nanoparticle assemblies (aHNPs) to blended PNCs in the regime of low dielectric contrast to establish how morphology and interface impact energy storage and breakdown across different polymer matrices (polystyrene, PS, and poly(methyl methacrylate), PMMA) and nanoparticle loadings (0-50% (v/v) silica). The findings indicate that the route (aHNP versus blending) to well-dispersed morphology has, at most, a minor impact on breakdown strength trends with nanoparticle volume fraction; the only exception being at intermediate loadings of silica in PMMA (15% (v/v)). Conversely, aHNPs show substantial improvements in reducing dielectric loss and maintaining charge/discharge efficiency. For example, low-frequency dielectric loss (1 Hz-1 kHz) of PS and PMMA aHNP films was essentially unchanged up to a silica content of 50% (v/v), whereas traditional blends showed a monotonically increasing loss with silica loading. Similar benefits are seen via high-field polarization loop measurements where energy storage for ∼15% (v/v) silica loaded PMMA and PS aHNPs were 50% and 200% greater than respective comparable PNC blends. Overall, these findings on low dielectric contrast PNCs clearly point to the performance benefits of

  16. The peculiar behavior of the glass transition temperature of amorphous drug-polymer films coated on inert sugar spheres.

    Science.gov (United States)

    Dereymaker, Aswin; Van Den Mooter, Guy

    2015-05-01

    Fluid bed coating has been proposed in the past as an alternative technology for manufacturing of drug-polymer amorphous solid dispersions, or so-called glass solutions. It has the advantage of being a one-step process, and thus omitting separate drying steps, addition of excipients, or manipulation of the dosage form. In search of an adequate sample preparation method for modulated differential scanning calorimetry analysis of beads coated with glass solutions, glass transition broadening and decrease of the glass transition temperature (Tg ) were observed with increasing particle size of crushed coated beads and crushed isolated films of indomethacin (INDO) and polyvinylpyrrolidone (PVP). Substituting INDO with naproxen gave comparable results. When ketoconazole was probed or the solvent in INDO-PVP films was switched to dichloromethane (DCM) or a methanol-DCM mixture, two distinct Tg regions were observed. Small particle sizes had a glass transition in the high Tg region, and large particle sizes had a glass transition in the low Tg region. This particle size-dependent glass transition was ascribed to different residual solvent amounts in the bulk and at the surface of the particles. A correlation was observed between the deviation of the Tg from that calculated from the Gordon-Taylor equation and the amount of residual solvent at the Tg of particles with different sizes. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  17. Clozapine-carboxylic acid plasticized co-amorphous dispersions: Preparation, characterization and solution stability evaluation

    Directory of Open Access Journals (Sweden)

    Ali Ahmed Mahmoud Abdelhaleem

    2015-06-01

    Full Text Available This study addressed the possibility of forming of co-amorphous systems between clozapine (CZ and various carboxylic acid plasticizers (CAPs. The aim was to improve the solubility and oral bioavailability of clozapine. Co-amorphous dispersions were prepared using modified solvent evaporation methodology at drug/plasticizer stoichiometric ratios of 1:1, 1:1.5 and 1:2. Solid state characterization was performed using differential scanning calorimetry, X-ray diffraction and infra red spectroscopy. Highly soluble homogeneous co-amorphous dispersions were formed between clozapine and CAPs via hydrogen bonding. The co-amorphous dispersions formed with tartaric acid (1:2 showed the highest dissolution percentage (> 95 % in 20 minutes compared to pure crystalline CZ (56 %. Highly stable solutions were obtained from co-amorphous CZ-citric and CZ-tartaric acid at 1:1.5 molar ratio. The prepared dispersions suggest the possibility of peroral or sublingual administration of highly soluble clozapine at a reduced dose with the great chance to bypass the first pass metabolism.

  18. Investigations into crazing in glassy amorphous polymers through molecular dynamics simulations

    Science.gov (United States)

    Venkatesan, Sudarkodi; Basu, Sumit

    2015-04-01

    In many glassy amorphous polymers, localisation of deformation during loading leads to crazes. Crazes are crack like features whose faces are bridged either by fibrils or a cellular network of voids and fibrils. While formation of crazes is aided by the presence of surface imperfections and embedded dust particles, in this work, we focus on intrinsic crazes that form spontaneously in the volume of the material. We perform carefully designed molecular dynamics simulations on well equilibrated samples of a model polymer with a view to gaining insights into certain incompletely understood aspects of the crazing process. These include genesis of the early nanovoids leading to craze nucleation, mechanisms of stabilising the cellular or fibrillar structure and the competition between chain scission and chain disentanglement in causing the final breakdown of the craze. Additionally, we identify and enumerate clusters of entanglement points with high functionality as effective topological constraints on macromolecular chains. We show that regions with low density of entanglement clusters serve as sites for nanovoid nucleation under high mean stress. Growth occurs by the repeated triggering of cavitation instabilities above a growing void. The growth of the void is aided by disentanglement in and flow of entanglements away from the cavitating region. Finally, for the chain lengths chosen, scission serves to supply short chains to the growing craze but breakdown occurs by complete disentanglement of the chains. In fact, most of the energy supplied to the material seems to be used in causing disentanglements and very little energy is required to create a stable fibril.

  19. A bifunctional amorphous polymer exhibiting equal linear and circular photoinduced birefringences.

    Science.gov (United States)

    Royes, Jorge; Provenzano, Clementina; Pagliusi, Pasquale; Tejedor, Rosa M; Piñol, Milagros; Oriol, Luis

    2014-11-01

    The large and reversible photoinduced linear and circular birefringences in azo-compounds are at the basis of the interest in these materials, which are potentially useful for several applications. Since the onset of the linear and circular anisotropies relies on orientational processes, which typically occur on the molecular and supramolecular length scale, respectively, a circular birefringence at least one order of magnitude lower than the linear one is usually observed. Here, the synthesis and characterization of an amorphous polymer with a dimeric repeating unit containing a cyanoazobenzene and a cyanobiphenyl moiety are reported, in which identical optical linear and circular birefringences are induced for proper light dose and ellipticity. A pump-probe technique and an analytical method based on the Stokes-Mueller formalism are used to investigate the photoinduced effects and to evaluate the anisotropies. The peculiar photoresponse of the polymer makes it a good candidate for applications in smart functional devices. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Osmotic pressure of ring polymer solutions : A Monte Carlo study

    NARCIS (Netherlands)

    Flikkema, Edwin; Brinke, Gerrit ten

    2000-01-01

    Using the wall theorem, the osmotic pressure of ring polymers in solution has been determined using an off-lattice topology conserving Monte Carlo algorithm. The ring polymers are modeled as freely-jointed chains with point-like beads, i.e., under conditions corresponding to θ-conditions for the

  1. Pressure-volume-temperature and excess molar volume prediction of amorphous and crystallizable polymer blends by equation of state

    Institute of Scientific and Technical Information of China (English)

    Fakhri Yousefi; Hajir Karimi; Maryam Gomar

    2015-01-01

    In this work the statistical mechanical equation of state was developed for volumetric properties of crystal ine and amorphous polymer blends. The Ihm–Song–Mason equations of state (ISMEOS) based on temperature and density at melting point (Tm andρm) as scaling constants were developed for crystalline polymers such as poly(propylene glycol)+poly(ethylene glycol)-200 (PPG+PEG-200), poly(ethylene glycol) methyl ether-300 (PEGME-350)+PEG-200 and PEGME-350+PEG-600. Furthermore, for amorphous polymer blends con-taining poly(2,6-dimethyl-1,4-phenylene oxide) (PPO)+polystyrene (PS) and PS+poly(vinylmethylether) (PVME), the density and surface tension at glass transition (ρg andγg) were used for estimation of second Virial coefficient. The calculation of second Virial coefficients (B2), effective van der Waals co-volume (b) and correction factor (α) was required for judgment about applicability of this model. The obtained results by ISMEOS for crys-talline and amorphous polymer blends were in good agreement with the experimental data with absolute aver-age deviations of 0.84%and 1.04%, respectively.

  2. Phase Equilibria for Complex Polymer Solutions

    DEFF Research Database (Denmark)

    Lindvig, Thomas; Hestkjær, L. L.; Hansen, A. F.

    2002-01-01

    the content of organic solvents. This work presents an investigation of the three polymer models Entropic-FV (EFV). UNIFAC-FV (UFV) and GC-Flory (GCF) for their capability of predicting solvent activity coefficients in binary systems containing complex polymers. It is possible to obtain good predictions...... at finite concentrations and satisfactory predictions at infinite dilution, particularly with the EFV model. The investigation shows that EFV is the most robust and stable of the models, which indicates that it is the most well suited model for further development of methods for predicting the miscibility...

  3. Scaling Behavior of Dendritic Nanoparticle Mobility in Semidilute Polymer Solutions

    NARCIS (Netherlands)

    Kort, de D.W.; Rombouts, W.H.; Hoeben, F.J.M.; Janssen, H.M.; As, van H.; Duynhoven, van J.P.M.

    2015-01-01

    In our studies on particle mobility in polymer solutions, we have investigated and determined self-diffusion coefficients of nanoparticles in semidilute solutions of poly(ethylene glycol) (PEG, Mw = 6, 20, 35, and 100 kDa). Specially designed PEGylated dendrimers with well-defined sizes (dh =

  4. Suppressive effects of a polymer sodium silicate solution on ...

    African Journals Online (AJOL)

    Sodium silicate was dissolved in water in either a monomer form or polymer form; the effects of both forms of sodium silicate aqueous solution on rose powdery mildew and root rot diseases of miniature rose were examined. Both forms of sodium silicate aqueous solution were applied to the roots of the miniature rose.

  5. Impact of soft annealing on the performance of solution-processed amorphous zinc tin oxide thin-film transistors

    KAUST Repository

    Nayak, Pradipta K.; Hedhili, Mohamed N.; Cha, Dong Kyu; Alshareef, Husam N.

    2013-01-01

    It is demonstrated that soft annealing duration strongly affects the performance of solution-processed amorphous zinc tin oxide thin-film transistors. Prolonged soft annealing times are found to induce two important changes in the device: (i) a

  6. Amorphous metal composites

    International Nuclear Information System (INIS)

    Byrne, M.A.; Lupinski, J.H.

    1984-01-01

    This patent discloses an improved amorphous metal composite and process of making the composite. The amorphous metal composite comprises amorphous metal (e.g. iron) and a low molecular weight thermosetting polymer binder. The process comprises placing an amorphous metal in particulate form and a thermosetting polymer binder powder into a container, mixing these materials, and applying heat and pressure to convert the mixture into an amorphous metal composite

  7. Interaction of derived polymers from pyrrole with biocompatible solutions

    International Nuclear Information System (INIS)

    Lopez G, O. G.

    2010-01-01

    This work presents a study about the synthesis by plasma, the electric properties and superficial interaction of polymers derived from pyrrole doped with Iodine with potential use as bio material. Poly-pyrrole is a semiconductor and biocompatible polymer with potential application in the development of artificial muscles and implants where the electric interaction between cells and material is an important variable. The syntheses were made at 13.5 MHz in a glass tubular reactor of 1500 cm 3 with electrodes of 6.5 cm diameter and stainless steel flanges. An electrode was connected to the RF terminal of the power supply that is combined with a matching coupling resistance. The monomer and dopant used in this work were pyrrole and Iodine respectively, in closed containers. They were vaporized and injected separately into the reactor at room temperature and 0.1 mbar. The vapors of the reagents mixed freely in the reactor. The synthesis time was 240 min at 40, 60, 80 and 100 W. The polymers were obtained as thin films adhered to the reactor walls. The films were washed and swollen with distilled water and removed from the reactor walls with a small spatula. The polymers were irradiated with gamma rays at 18 and 22 KGy. Due to the fact that the doses are cumulative, the final dose applied was 40 KGy. The polymers characterization was carried out by Fourier Transform Infrared Spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy, contact angle, electrical conductivity and X-ray diffraction. The analyses indicates that the polymers have very similar structure in almost the entire power range, showing C-O, C=C, C-H, O-H, N-H bonds with a predominantly amorphous structure. The TGA analyses showed that the material has 4 or 5 loses of material. The first one starts after that 115 C except for the material irradiated at 40 KGy, this one begins in 87 C, the second one is in the interval of 196 and 295 C, the third one between 311 and 500 C, and the last

  8. Polymer diffusion in the interphase between surface and solution.

    Science.gov (United States)

    Weger, Lukas; Weidmann, Monika; Ali, Wael; Hildebrandt, Marcus; Gutmann, Jochen Stefan; Hoffmann-Jacobsen, Kerstin

    2018-05-22

    Total internal reflection fluorescence correlation spectroscopy (TIR-FCS) is applied to study the self-diffusion of polyethylene glycol solutions in the presence of weakly attractive interfaces. Glass coverslips modified with aminopropyl- and propyl-terminated silanes are used to study the influence of solid surfaces on polymer diffusion. A model of three phases of polymer diffusion allows to describe the experimental fluorescence autocorrelation functions. Besides the two-dimensional diffusion of adsorbed polymer on the substrate and three-dimensional free diffusion in bulk solution, a third diffusion time scale is observed with intermediate diffusion times. This retarded three-dimensional diffusion in solution is assigned to long range effects of solid surfaces on diffusional dynamics of polymers. The respective diffusion constants show Rouse scaling (D~N -1 ) indicating a screening of hydrodynamic interactions by the presence of the surface. Hence, the presented TIR-FCS method proves to be a valuable tool to investigate the effect of surfaces on polymer diffusion beyond the first adsorbed polymer layer on the 100 nm length scale.

  9. Stochastic entangled chain dynamics of dense polymer solutions.

    Science.gov (United States)

    Kivotides, Demosthenes; Wilkin, S Louise; Theofanous, Theo G

    2010-10-14

    We propose an adjustable-parameter-free, entangled chain dynamics model of dense polymer solutions. The model includes the self-consistent dynamics of molecular chains and solvent by describing the former via coarse-grained polymer dynamics that incorporate hydrodynamic interaction effects, and the latter via the forced Stokes equation. Real chain elasticity is modeled via the inclusion of a Pincus regime in the polymer's force-extension curve. Excluded volume effects are taken into account via the combined action of coarse-grained intermolecular potentials and explicit geometric tracking of chain entanglements. We demonstrate that entanglements are responsible for a new (compared to phantom chain dynamics), slow relaxation mode whose characteristic time scale agrees very well with experiment. Similarly good agreement between theory and experiment is also obtained for the equilibrium chain size. We develop methods for the solution of the model in periodic flow domains and apply them to the computation of entangled polymer solutions in equilibrium. We show that the number of entanglements Π agrees well with the number of entanglements expected on the basis of tube theory, satisfactorily reproducing the latter's scaling of Π with the polymer volume fraction φ. Our model predicts diminishing chain size with concentration, thus vindicating Flory's suggestion of excluded volume effects screening in dense solutions. The predicted scaling of chain size with φ is consistent with the heuristic, Flory theory based value.

  10. A phenomenological model for the chemo-responsive shape memory effect in amorphous polymers undergoing viscoelastic transition

    International Nuclear Information System (INIS)

    Lu, Haibao; Huang, Wei Min

    2013-01-01

    We present a phenomenological approach to study the viscoelastic transition and working mechanism of the chemo-responsive shape memory effect (SME) in amorphous shape memory polymers (SMPs). Both the copolymerization viscosity model and Doolittle equation are initially applied to quantitatively identify the influential factors behind the chemo-responsive SME in the SMPs exposure to a right solvent. After this, the Williams–Landel–Ferry (WLF) equation is employed to couple the viscosity (η), time–temperature shift factor (α τ ) and glass transition temperature (T g ) in amorphous polymers. By means of combining the WLF and Arrhenius equations together, the inductively decreased transition temperature is confirmed as the driving force for the chemo-responsive SME. Finally, a phenomenological viscoelastic model is proposed and then verified by the available experimental data reported in the literature and then compared with the simulation results of a semi-empirical model. This phenomenological model is expected to provide a powerful simulation tool for theoretical prediction and experimental substantiation of the chemo-responsive SME in amorphous SMPs by viscoelastic transition. (paper)

  11. Laser synthesis of aluminium nanoparticles in biocompatible polymer solutions

    Science.gov (United States)

    Singh, Rina; Soni, R. K.

    2014-08-01

    Pulsed laser ablation of Aluminium (Al) in pure water rapidly forms a thin alumina (Al2O3) layer which drastically modifies surface plasmon resonance (SPR) absorption characteristics in deep-UV region. Initially, pure aluminium nanoparticles (NPs) are generated in water without any stabilizers or surfactants at low laser fluence which gradually transform to stable Al-Al2O3 core-shell nanostructure with increasing either residency time or fluence. The role of laser wavelength and fluence on the SPR properties and oxidation characteristics of Al NPs has been investigated in detail. We also present a one-step in situ synthesis of oxide-free stable Al NPs in biocompatible polymer solutions using laser ablation in liquid method. We have used nonionic polymers (PVP, PVA and PEG) and anionic surfactant (SDS) stabilizer to suppress the Al2O3 formation and studied the effect of polymer functional group, polymeric chain length, polymer concentration and anionic surfactant on the incipient embryonic aluminium particles and their sizes. The different functional groups of polymers resulted in different oxidation states of Al. PVP and PVA polymers resulted in pure Al NPs; however, PEG and SDS resulted in alumina-modified Al NPs. The Al nanoparticles capped with PVP, PVA, and PEG show a good correlation between nanoparticle stability and monomeric length of the polymer chain.

  12. Alumina nanoparticle/polymer nanocomposite dielectric for flexible amorphous indium-gallium-zinc oxide thin film transistors on plastic substrate with superior stability

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Hsin-Cheng [Department of Electrical Engineering, National Chung Hsing University, Taichung 40227, Taiwan (China); Pei, Zingway, E-mail: zingway@dragon.nchu.edu.tw [Department of Electrical Engineering, National Chung Hsing University, Taichung 40227, Taiwan (China); Graduate Institute of Optoelectronic Engineering, National Chung Hsing University, Taichung 40227, Taiwan (China); Center of Nanoscience and Nanotechnology, National Chung Hsing University, Taichung 40227, Taiwan (China); Jian, Jyun-Ruri; Tzeng, Bo-Jie [Graduate Institute of Optoelectronic Engineering, National Chung Hsing University, Taichung 40227, Taiwan (China)

    2014-07-21

    In this study, the Al{sub 2}O{sub 3} nanoparticles were incorporated into polymer as a nono-composite dielectric for used in a flexible amorphous Indium-Gallium-Zinc Oxide (a-IGZO) thin-film transistor (TFT) on a polyethylene naphthalate substrate by solution process. The process temperature was well below 100 °C. The a-IGZO TFT exhibit a mobility of 5.13 cm{sup 2}/V s on the flexible substrate. After bending at a radius of 4 mm (strain = 1.56%) for more than 100 times, the performance of this a-IGZO TFT was nearly unchanged. In addition, the electrical characteristics are less altered after positive gate bias stress at 10 V for 1500 s. Thus, this technology is suitable for use in flexible displays.

  13. Ideal solution behaviour of glassy Cu–Ti, Zr, Hf alloys and properties of amorphous copper

    International Nuclear Information System (INIS)

    Ristić, R.; Cooper, J.R.; Zadro, K.; Pajić, D.; Ivkov, J.; Babić, E.

    2015-01-01

    Highlights: • Ideal solution behaviour (ISB) is established in all Cu–Ti, Zr, Hf glassy alloys. • ISB enables reliable estimates for various properties of amorphous Cu. • ISB also impacts glass forming ability in these and probably other similar alloys. - Abstract: A comprehensive study of selected properties of amorphous (a) Cu–TE alloys (TE = Ti, Zr and Hf) has been performed. Data for average atomic volumes of a-Cu–Hf, Ti alloys combined with literature data show that ideal solution behaviour (Vegard’s law) extends over the whole glass forming range (GFR) in all a-Cu–TE alloys. This enables one to obtain an insight into some properties and probable atomic arrangements for both, a-TEs (Ristić et al., 2010) and a-Cu by extrapolation of the data for alloys. Indeed the atomic volumes and other properties studied for all a-Cu–TE alloys extrapolate to the same values for a-Cu. Depending on the property, these values are either close to those of crystalline (c) Cu, or are close to those for liquid (L) Cu. In particular, the electronic transport properties of a-Cu seem close to those of L-Cu, whereas the static properties, such as the density of states, and Young’s modulus, converge to those of c-Cu. The possible impact of these results on our understanding of a-Cu–TE alloys, including glass forming ability, is discussed

  14. Nonequilibrium thermodynamics of dilute polymer solutions in flow.

    Science.gov (United States)

    Latinwo, Folarin; Hsiao, Kai-Wen; Schroeder, Charles M

    2014-11-07

    Modern materials processing applications and technologies often occur far from equilibrium. To this end, the processing of complex materials such as polymer melts and nanocomposites generally occurs under strong deformations and flows, conditions under which equilibrium thermodynamics does not apply. As a result, the ability to determine the nonequilibrium thermodynamic properties of polymeric materials from measurable quantities such as heat and work is a major challenge in the field. Here, we use work relations to show that nonequilibrium thermodynamic quantities such as free energy and entropy can be determined for dilute polymer solutions in flow. In this way, we determine the thermodynamic properties of DNA molecules in strong flows using a combination of simulations, kinetic theory, and single molecule experiments. We show that it is possible to calculate polymer relaxation timescales purely from polymer stretching dynamics in flow. We further observe a thermodynamic equivalence between nonequilibrium and equilibrium steady-states for polymeric systems. In this way, our results provide an improved understanding of the energetics of flowing polymer solutions.

  15. Numerical Simulation and Experimental Investigation of the Viscoelastic Heating Mechanism in Ultrasonic Plasticizing of Amorphous Polymers for Micro Injection Molding

    Directory of Open Access Journals (Sweden)

    Bingyan Jiang

    2016-05-01

    Full Text Available Ultrasonic plasticizing of polymers for micro-injection molding has been proposed and studied for its unique potential in materials and energy-saving. In our previous work, we have demonstrated the characteristics of the interfacial friction heating mechanism in ultrasonic plasticizing of polymer granulates. In this paper, the other important heating mechanism in ultrasonic plasticizing, i.e., viscoelastic heating for amorphous polymer, was studied by both theoretical modeling and experimentation. The influence mechanism of several parameters, such as the initial temperature of the polymer, the ultrasonic frequency, and the ultrasonic amplitude, was investigated. The results from both numerical simulation and experimentation indicate that the heat generation rate of viscoelastic heating can be significantly influenced by the initial temperature of polymer. The glass transition temperature was found to be a significant shifting point in viscoelastic heating. The heat generation rate is relatively low at the beginning and can have a steep increase after reaching glass transition temperature. In comparison with the ultrasonic frequency, the ultrasonic amplitude has much greater influence on the heat generation rate. In light of the quantitative difference in the viscoelastic heating rate, the limitation of the numerical simulation was discussed in the aspect of the assumptions and the applied mathematical models.

  16. Characterization of amorphous yttria layers deposited by aqueous solutions of Y-chelate alkoxides complex

    Science.gov (United States)

    Kim, Young-Soon; Lee, Yu-Ri; Kim, Byeong-Joo; Lee, Jae-Hun; Moon, Seung-Hyun; Lee, Hunju

    2015-01-01

    Crack-free amorphous yttria layers were deposited by dip coating in solutions of different Y-chelate alkoxides complex. Three Y-chelate solutions of different concentrations were prepared using yttrium acetate tetrahydrate, yttrium stearic acid as Y source materials. PEG, diethanolamine were used as chelating agents, while ethanol, methanol and tetradecane were used as solvent. Three different combinations of chelating and solvents were used to prepare solutions for Y2O3 dip coating on SUS, electropolished and non-electropolished Hastelloy C-276 substrates. The thickness of the films was varied by changing the number of dipping cycles. At an optimized condition, the substrate surface roughness (rms) value was reduced from ∼50 nm to ∼1 nm over a 10 × 10 μm2 area. After Y2O3 deposition, MgO was deposited using ion-beam assisted deposition (IBAD), then LaMnO3 (LMO) was deposited using sputtering and GdBCO was deposited using reactive co-evaporation by deposition and reaction (RCE-DR). Detailed X-ray study indicates that LMO/MgO/Y2O3 and GdBCO/LMO/MgO/Y2O3 stack films have good out-of-plane and in-plane textures with strong c-axis alignment. The critical current (Ic) of GdBCO/LMO/MgO/Y2O3 multilayer structure varied from 190 to 420 A/cm with different solutions, when measured at 77 K. These results demonstrated that amorphous yttria can be easily deposited by dip coating using Y-chelates complex as a diffusion barrier and nucleation layer.

  17. Stabilization of polymer solutions in the presence of oxidizing agents

    Energy Technology Data Exchange (ETDEWEB)

    Mendez, A; Serino, A; Jenkins, D; Lichaa, P M

    1974-01-01

    Many investigators in the field of heavy oil recovery techniques have confirmed the recovery efficiency which, in the miscible displacement method, has utilized polymer solutions as additives to the injection fluids. The viscosity increase of the displacing phase has lowered the mobility ratio with a significant improvement in the sweep efficiency. Recently, others have reported a notable improvement in the recovery of heavy crude by this same method of miscible displacement which causes a mobile fluid bank between the crude and the displacing fluid. There is an intervening oxidation reaction, promoting the in situ formation of surface-active agents on the interface of these 2 fluids. This study describes the effect on degradation of polymer solutions by such oxidizing agents as potassium chromate and potassium permanganate. The degradation of any polymer solution with or without additives is increased materially by an increase in temperature. The presence of NaCl brine is not often of any great significance in the time of gelation, especially with polymers of the polysaccharide type. (18 refs.)

  18. Dynamic structurization in solutions of hydrodynamically active polymers

    International Nuclear Information System (INIS)

    Pogrebnyak, V.G.; Tverdokhleb, S.V.; Naumchuk, N.V.

    1993-01-01

    The processes of ordering and self-regulation in nonlinear systems have attracted great attention because understanding the principles of self-regulation and its thermodynamics can become a clue to many physical phenomena. In this work, it is experimentally established that, under the condition of elongational flows, dynamic structurization and periodic processes may originate in the solutions of flexible, hydrodynamically-active polymers due to self-regulation in these systems. The hydrodynamic elongational field was created using the flow of a Newtonian liquid (water, acetone, dioxane) converging to a small opening. The hydrodynamically-active polymers were polyethylene oxide or hydrolyzed polyacrylamide

  19. Characterization of amorphous yttria layers deposited by aqueous solutions of Y-chelate alkoxides complex

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young-Soon, E-mail: kyscjb@i-sunam.com; Lee, Yu-Ri; Kim, Byeong-Joo; Lee, Jae-Hun; Moon, Seung-Hyun; Lee, Hunju

    2015-01-15

    Highlights: • Economical method for crack-free amorphous yttria layer deposition by dip coating. • Simpler process for planar yttria film as a diffusion barrier and nucleation layer. • Easy control over the film properties with better characteristics. • Easy control over the thickness of the deposited films. • A feasible process that can be easily adopted by HTSCC industries. - Abstract: Crack-free amorphous yttria layers were deposited by dip coating in solutions of different Y-chelate alkoxides complex. Three Y-chelate solutions of different concentrations were prepared using yttrium acetate tetrahydrate, yttrium stearic acid as Y source materials. PEG, diethanolamine were used as chelating agents, while ethanol, methanol and tetradecane were used as solvent. Three different combinations of chelating and solvents were used to prepare solutions for Y{sub 2}O{sub 3} dip coating on SUS, electropolished and non-electropolished Hastelloy C-276 substrates. The thickness of the films was varied by changing the number of dipping cycles. At an optimized condition, the substrate surface roughness (rms) value was reduced from ∼50 nm to ∼1 nm over a 10 × 10 μm{sup 2} area. After Y{sub 2}O{sub 3} deposition, MgO was deposited using ion-beam assisted deposition (IBAD), then LaMnO{sub 3} (LMO) was deposited using sputtering and GdBCO was deposited using reactive co-evaporation by deposition and reaction (RCE-DR). Detailed X-ray study indicates that LMO/MgO/Y{sub 2}O{sub 3} and GdBCO/LMO/MgO/Y{sub 2}O{sub 3} stack films have good out-of-plane and in-plane textures with strong c-axis alignment. The critical current (Ic) of GdBCO/LMO/MgO/Y{sub 2}O{sub 3} multilayer structure varied from 190 to 420 A/cm with different solutions, when measured at 77 K. These results demonstrated that amorphous yttria can be easily deposited by dip coating using Y-chelates complex as a diffusion barrier and nucleation layer.

  20. Dilute-solution Structure of Charged Arborescent Graft Polymer

    International Nuclear Information System (INIS)

    Yun, Seok; Briber, R.M.; Kee, R. Andrew; Gauthier, Mario

    2006-01-01

    The solutions of charged G1 arborescent polystyrene-graft-poly(2-vinylpyridine) copolymers in methanol-d4 and D 2 O were investigated over a dilute concentration range φ = 0.005-0.05 (φ: mass fraction) using small-angle neutron scattering (SANS). Upon addition of acid (HCl) arborescent graft polymers became charged and a peak appeared in SANS data. The interparticle distance (d exp ) calculated from a peak position corresponded to the expected value (d uni ) for a uniform particle distribution. This indicates the formation of liquid-like ordering due to long-range Coulombic repulsions. The smaller dielectric constant of methanol-d4 resulted in long-range electrostatic repulsions persisting to lower polymer concentration than in D 2 O. The slow mode scattering was observed by dynamic light scattering measurements for the same polymer solutions, indicating the presence of structural inhomogeneity in the solutions. Both the peak and slow mode disappeared by addition of NaCl or excess HCl into the solutions due to the screening of electrostatic interactions. The G1 polymer grafted with longer P2VP chains (M w ∼ 30,000 versus 5000 g mol) formed a gel on addition of HCl. This result reveals that molecular expansion is more significant for arborescent polymers with longer (M w ∼ 30,000) linear polyelectrolyte branches, resulting in gelation for φ > 0.01. Upon addition of NaCl or excess HCl a gel transformed back to a liquid resulted from the screening of electrostatic interactions.

  1. A Comprehensive study of the Effects of Chain Morphology on the Transport Properties of Amorphous Polymer Films

    Science.gov (United States)

    Mendels, Dan; Tessler, Nir

    2016-07-01

    Organic semiconductors constitute one of the main components underlying present-day paradigm shifting optoelectronic applications. Among them, polymer based semiconductors are deemed particularly favorable due to their natural compatibility with low-cost device fabrication techniques. In light of recent advances in the syntheses of these classes of materials, yielding systems exhibiting charge mobilities comparable with those found in organic crystals, a comprehensive study of their charge transport properties is presented. Among a plethora of effects arising from these systems morphological and non morphological attributes, it is shown that a favorable presence of several of these attributes, including that of rapid on-chain carrier propagation and the presence of elongated conjugation segments, can lead to an enhancement of the system’s mobility by more than 5 orders of magnitude with respect to ‘standard’ amorphous organic semiconductors. New insight for the formulation of new engineering strategies for next generation polymer based semiconductors is thus gathered.

  2. Amorphous infinite coordination polymer microparticles: a new class of selective hydrogen storage materials

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, You-Moon; Heo, Jungseok; Mirkin, Chad A [Department of Chemistry, International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL (United States); Armatas, Gerasimos S [Department of Chemistry, Northwestern University, Evanston, IL (United States); Kanatzidis, Mercouri G [Materials Science Division, Argonne National Laboratory, Argonne, IL (United States)

    2008-06-04

    A new class of micrometer-sized amorphous infinite coordination particles is selectively prepared from the coordination chemistry of a metallo-salen building block and Zn{sup 2+} ions. The particles show moderately high H{sub 2} uptake and almost no N{sub 2} adsorption, even though they are amorphous and do not have the well-defined channels typically used to explain such selectivity in metal-organic framework systems. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  3. Inhibition of crystal nucleation and growth by water-soluble polymers and its impact on the supersaturation profiles of amorphous drugs.

    Science.gov (United States)

    Ozaki, Shunsuke; Kushida, Ikuo; Yamashita, Taro; Hasebe, Takashi; Shirai, Osamu; Kano, Kenji

    2013-07-01

    The impact of water-soluble polymers on drug supersaturation behavior was investigated to elucidate the role of water-soluble polymers in enhancing the supersaturation levels of amorphous pharmaceuticals. Hydroxypropyl methylcellulose (HPMC), polyvinylpyrrolidone (PVP), and Eudragit L-100 (Eudragit) were used as representative polymers, and griseofulvin and danazol were used as model drugs. Supersaturation profiles of amorphous drugs were measured in biorelevant dissolution tests. Crystal growth rate was measured from the decrease in dissolved drug concentration in the presence of seed crystals. Nucleation kinetics was evaluated by measuring the induction time for nucleation. All experiments were performed in the presence and absence of polymers. The degree of supersaturation of the amorphous model drugs increased with an increase in the inhibitory efficiency of polymers against crystal nucleation and growth (HPMC > PVP > Eudragit). In the presence of HPMC, the addition of seed crystals diminished the supersaturation ratio dramatically for griseofulvin and moderately for danazol. The results demonstrated that the polymers contributed to drug supersaturation by inhibiting both nucleation and growth. The effect of the polymers was drug dependent. The detailed characterization of polymers would allow selection of appropriate crystallization inhibitors and a planned quality control strategy for the development of supersaturable formulations. Copyright © 2013 Wiley Periodicals, Inc.

  4. Effects of Intercalation on the Hole Mobility of Amorphous Semiconducting Polymer Blends

    KAUST Repository

    Cates, Nichole C.; Gysel, Roman; Dahl, Jeremy E. P.; Sellinger, Alan; McGehee, Michael D.

    2010-01-01

    Fullerenes have been shown to intercalate between the side chains of many crystalline and semicrystalline polymers and to affect the properties of polymer:fullerene bulk heterojunction solar cells. Here we present the first in-depth study

  5. Bulk-volume behavior of pressure-densified amorphous polymers and free-volume behavior by positron annihilation lifetime measurement

    International Nuclear Information System (INIS)

    Hagiwara, K.; Ougizawa, T.; Inoue, T.; Hirata, K.; Kobayashi, Y.

    2001-01-01

    In order to study the nature of amorphous polymers, the free volume contribution on the bulk volume change was investigated on the basis of the relationship between the bulk volume behavior by PVT (pressure-volume-temperature) measurement and the free volume behavior by PALS (positron annihilation lifetime spectroscopy) measurement. A densified glass, prepared by cooling at constant rate from the melt state temperature to room temperature under 200 MPa, showed smaller bulk volume and free volume than non-densified glass. And the densified glass showed not only the same glass transition temperature (Tg) as non-densified glass but also another transition at lower temperature around (Tg-30 C). In this glass-glass transition, both the bulk volume and free volume of densified glass recovered to those of non-densified glass. Moreover the densified glass showed different thermal behavior from the glass which was enthalpy-relaxed under atmospheric pressure. From those results, it was considered that the free volume behavior largely related to the behavior of amorphous polymers. (orig.)

  6. Influence of mechanically-induced dilatation on the shape memory behavior of amorphous polymers at large deformation

    Science.gov (United States)

    Hanzon, Drew W.; Lu, Haibao; Yakacki, Christopher M.; Yu, Kai

    2018-01-01

    In this study, we explore the influence of mechanically-induced dilatation on the thermomechanical and shape memory behavior of amorphous shape memory polymers (SMPs) at large deformation. The uniaxial tension, glass transition, stress relaxation and free recovery behaviors are examined with different strain levels (up to 340% engineering strain). A multi-branched constitutive model that incorporates dilatational effects on the polymer relaxation time is established and applied to assist in discussions and understand the nonlinear viscoelastic behaviors of SMPs. It is shown that the volumetric dilatation results in an SMP network with lower viscosity, faster relaxation, and lower Tg. The influence of the dilatational effect on the thermomechanical behaviors is significant when the polymers are subject to large deformation or in a high viscosity state. The dilation also increases the free recovery rate of SMP at a given recovery temperature. Even though the tested SMPs are far beyond their linear viscoelastic region when a large programming strain is applied, the free recovery behavior still follows the time-temperature superposition (TTSP) if the dilatational effect is considered during the transformation of time scales; however, if the programming strain is different, TTSP fails in predicting the recovery behavior of SMPs because the network has different entropy state and driving force during shape recovery. Since most soft active polymers are subject to large deformation in practice, this study provides a theoretical basis to better understand their nonlinear viscoelastic behaviors, and optimize their performance in engineering applications.

  7. Dynamic dilution exponent in monodisperse entangled polymer solutions

    DEFF Research Database (Denmark)

    Shahid, T.; Huang, Qian; Oosterlinck, F.

    2017-01-01

    of concentration but also depends on the molar mass of the chains. While the proposed approach successfully explains the viscoelastic properties of a large number of semi-dilute solutions of polymers in their own oligomers, important discrepancies are found for semi-dilute entangled polymers in small-molecule......We study and model the linear viscoelastic properties of several entangled semi-dilute and concentrated solutions of linear chains of different molar masses and at different concentrations dissolved in their oligomers. We discuss the dilution effect of the oligomers on the entangled long chains....... In particular, we investigate the influence of both concentration and molar mass on the value of the effective dynamic dilution exponent determined from the level of the storage plateau at low and intermediate frequencies. We show that the experimental results can be quantitatively explained by considering...

  8. Light scattering from polymer solutions and nanoparticle dispersions

    CERN Document Server

    Schärtl, Wolfgang; Janca, Josef

    2007-01-01

    Light scattering is a very powerful method to characterize the structure of polymers and nanoparticles in solution. Recent technical developments have strongly enhanced the possible applications of this technique, overcoming previous limitations like sample turbidity or insufficient experimental time scales. However, despite their importance, these new developments have not yet been presented in a comprehensive form. In addition, and maybe even more important to the broad audience, there lacks a simple-to-read textbook for students and non-experts interested in the basic principles and fundamental techniques of light scattering. As part of the Springer Laboratory series, this book tries not only to provide such a simple-to-read and illustrative textbook about the seemingly very complicated topic of light scattering from polymers and nanoparticles in dilute solution, but also intends to cover some of the newest technical developments in experimental light scattering.

  9. Highly conductive p-type amorphous oxides from low-temperature solution processing

    International Nuclear Information System (INIS)

    Li Jinwang; Tokumitsu, Eisuke; Koyano, Mikio; Mitani, Tadaoki; Shimoda, Tatsuya

    2012-01-01

    We report solution-processed, highly conductive (resistivity 1.3-3.8 mΩ cm), p-type amorphous A-B-O (A = Bi, Pb; B = Ru, Ir), processable at temperatures (down to 240 °C) that are compatible with plastic substrates. The film surfaces are smooth on the atomic scale. Bi-Ru-O was analyzed in detail. A small optical bandgap (0.2 eV) with a valence band maximum (VBM) below but very close to the Fermi level (binding energy E VBM = 0.04 eV) explains the high conductivity and suggests that they are degenerated semiconductors. The conductivity changes from three-dimensional to two-dimensional with decreasing temperature across 25 K.

  10. Modeling of amorphous pocket formation in silicon by numerical solution of the heat transport equation

    International Nuclear Information System (INIS)

    Kovac, D.; Otto, G.; Hobler, G.

    2005-01-01

    In this paper we present a model of amorphous pocket formation that is based on binary collision simulations to generate the distribution of deposited energy, and on numerical solution of the heat transport equation to describe the quenching process. The heat transport equation is modified to consider the heat of melting when the melting temperature is crossed at any point in space. It is discretized with finite differences on grid points that coincide with the crystallographic lattice sites, which allows easy determination of molten atoms. Atoms are considered molten if the average of their energy and the energy of their neighbors meets the melting criterion. The results obtained with this model are in good overall agreement with published experimental data on P, As, Te and Tl implantations in Si and with data on the polyatomic effect at cryogenic temperature

  11. Crossover to entangled dynamics in polymer solutions and melts

    International Nuclear Information System (INIS)

    Schweizer, K.S.; Szamel, G.

    1995-01-01

    A statistical dynamical theory of the crossover from unentangled Rouse dynamics to entangled behavior is constructed for chain polymer solutions and melts. Both time and spatial crossovers in long chain fluids, and the degree of polymerization crossover for short polymers, are treated. The analysis is based on a microscopic theory of the perturbative dynamical corrections to Rouse theory arising from chain connectivity and intermolecular excluded volume forces. The dependence of crossover properties such as the plateau shear modulus and entanglement time and length scale on solution density, solvent quality, and chain statistical segment length are derived by combining the dynamical theory with equilibrium liquid state integral equation methods. Scaling relations are obtained which appear to be in general accord with most experiments on both solutions and melts. The physical origin of the predicted scaling behaviors is the fractional power law temporal decay of the entanglement friction memory function on intermediate time scales, and power law reduced density dependence of the equilibrium force correlations. The theory is also applied to compute the dependence of the chain normal mode relaxation times on polymer density and chain length. Favorable qualitative comparisons with recent neutron spin echo experiments are made. copyright 1995 American Institute of Physics

  12. Limitations of amorphous content quantification by isothermal calorimetry using saturated salt solutions to control relative humidity: alternative methods.

    Science.gov (United States)

    Khalef, Nawel; Pinal, Rodolfo; Bakri, Aziz

    2010-04-01

    Despite the high sensitivity of isothermal calorimetry (IC), reported measurements of amorphous content by this technique show significant variability even for the same compound. An investigation into the reasons behind such variability is presented using amorphous lactose and salbutamol sulfate as model compounds. An analysis was carried out on the heat evolved as a result of the exchange of water vapor between the solid sample during crystallization and the saline solution reservoir. The use of saturated salt solutions as means of control of the vapor pressure of water within sealed ampoules bears inherent limitations that lead in turn to the variability associated with the IC technique. We present an alternative IC method, based on an open cell configuration that effectively addresses the limitations encountered with the sealed ampoule system. The proposed approach yields an integral whose value is proportional to the amorphous content in the sample, thus enabling reliable and consistent quantifications. 2009 Wiley-Liss, Inc. and the American Pharmacists Association

  13. Sequentially solution-processed, nanostructured polymer photovoltaics using selective solvents

    KAUST Repository

    Kim, Do Hwan; Mei, Jianguo; Ayzner, Alexander L.; Schmidt, Kristin; Giri, Gaurav; Appleton, Anthony L.; Toney, Michael F.; Bao, Zhenan

    2014-01-01

    We demonstrate high-performance sequentially solution-processed organic photovoltaics (OPVs) with a power conversion efficiency (PCE) of 5% for blend films using a donor polymer based on the isoindigo-bithiophene repeat unit (PII2T-C10C8) and a fullerene derivative [6,6]-phenyl-C[71]-butyric acid methyl ester (PC71BM). This has been accomplished by systematically controlling the swelling and intermixing processes of the layer with various processing solvents during deposition of the fullerene. We find that among the solvents used for fullerene deposition that primarily swell but do not re-dissolve the polymer underlayer, there were significant microstructural differences between chloro and o-dichlorobenzene solvents (CB and ODCB, respectively). Specifically, we show that the polymer crystallite orientation distribution in films where ODCB was used to cast the fullerene is broad. This indicates that out-of-plane charge transport through a tortuous transport network is relatively efficient due to a large density of inter-grain connections. In contrast, using CB results in primarily edge-on oriented polymer crystallites, which leads to diminished out-of-plane charge transport. We correlate these microstructural differences with photocurrent measurements, which clearly show that casting the fullerene out of ODCB leads to significantly enhanced power conversion efficiencies. Thus, we believe that tuning the processing solvents used to cast the electron acceptor in sequentially-processed devices is a viable way to controllably tune the blend film microstructure. © 2014 The Royal Society of Chemistry.

  14. Segment-based Eyring-Wilson viscosity model for polymer solutions

    International Nuclear Information System (INIS)

    Sadeghi, Rahmat

    2005-01-01

    A theory-based model is presented for correlating viscosity of polymer solutions and is based on the segment-based Eyring mixture viscosity model as well as the segment-based Wilson model for describing deviations from ideality. The model has been applied to several polymer solutions and the results show that it is reliable both for correlation and prediction of the viscosity of polymer solutions at different molar masses and temperature of the polymer

  15. Chemical metallization of KMPR photoresist polymer in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Zeb, Gul [MiQro Innovation Collaborative Centre (C2MI), 45, boul. de l' Aéroport, Bromont, QC, J2L 1S8 (Canada); Mining & Materials Engineering, McGill University, 3610,University Street, Montreal, QC, H3A 0C5 (Canada); Duong, Xuan Truong [Department of Mechanical Engineering, Ecole polytechnique de Montréal, Montréal, QC, H3C 3T5 (Canada); Thai Nguyen University of Technology, 3-2 Street, Thai Nguyen City (Viet Nam); Vu, Ngoc Pi; Phan, Quang The; Nguyen, Duc Tuong; Ly, Viet Anh [Thai Nguyen University of Technology, 3-2 Street, Thai Nguyen City (Viet Nam); Salimy, Siamak [ePeer Review LLC, 145 Pine Haven Shores Rd, Suite 1000-X, Shelburne, VT 05482 (United States); Le, Xuan Tuan, E-mail: xuantuan.le@teledyne.com [MiQro Innovation Collaborative Centre (C2MI), 45, boul. de l' Aéroport, Bromont, QC, J2L 1S8 (Canada); Thai Nguyen University of Technology, 3-2 Street, Thai Nguyen City (Viet Nam)

    2017-06-15

    Highlights: • Electroless deposition of Ni-B film on KMPR photoresist polymer insulator with excellent adhesion has been achieved. • This metallization has been carried out in aqueous solutions at low temperature. • Polyamine palladium complexes grafts serve as seeds for the electroless plating on KMPR. • This electroless metallization process is simple, industrially feasible, chromium-free and environment-friendly. - Abstract: While conventional methods for preparing thin films of metals and metallic alloys on insulating substrates in the field of microelectromechanical systems (MEMS) include vapor deposition techniques, we demonstrate here that electroless deposition can be considered as an alternate efficient approach to metallize the surface of insulating substrates, such as KMPR epoxy photoresist polymer. In comparison with the physical and chemical vapor deposition methods, which are well-established for metallization of photoresist polymers, our electroless nickel plating requires only immersing the substrates into aqueous solutions in open air at low temperatures. Thin films of nickel alloy have been deposited electrolessly on KMPR surface, through a cost-effective and environmental chromium-free process, mediated through direct grafting of amine palladium complexes in aqueous medium. This covalent organic coating provides excellent adhesion between KMPR and the nickel film and allows better control of the palladium catalyst content. Covalent grafting and characterization of the deposited nickel film have been carried out by means of Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy techniques.

  16. Diffusion of Lithium Ions in Amorphous and Crystalline Poly(ethylene oxide)_3:LiCF_3SO_3 Polymer Electrolytes

    International Nuclear Information System (INIS)

    Xue, Sha; Liu, Yingdi; Li, Yaping; Teeters, Dale; Crunkleton, Daniel W.; Wang, Sanwu

    2017-01-01

    The PEO_3:LiCF_3SO_3 polymer electrolyte has attracted significant research due to high conductivity and enhanced stability in lithium polymer batteries. Most experimental studies have shown that amorphous PEO lithium salt electrolytes have higher conductivity than the crystalline ones. Other studies, however, have shown that crystalline PEO salt complexes can conduct ions. As a result, further theoretical investigations are warranted to help clarify the issue. In this work, we use density functional theory with the climbing image nudged elastic band method to investigate the atomic-scale mechanism of lithium ion transport in the polymer electrolytes. We also use density functional theory and ab initio molecular dynamics simulations to obtain the amorphous structure of PEO_3:LiCF_3SO_3. The diffusion pathways and activation energies of lithium ions in both crystalline and amorphous PEO_3:LiCF_3SO_3 are determined. In crystalline PEO_3:LiCF_3SO_3, the activation energy for the low-barrier diffusion pathway is approximately 1.0 eV. In the amorphous phase, the value is 0.6 eV. This result would support the experimental observation that amorphous PEO_3:LiCF_3SO_3 has higher ionic conductivity than the crystalline phase.

  17. Study of amorphous semiconductors doped with rare earths (Gd and Er) and conducting polymers by EPR techniques and magnetic susceptibility

    International Nuclear Information System (INIS)

    Sercheli, Mauricio da Silva

    1999-01-01

    This thesis involves the study of amorphous semiconductors and conducting polymers, which have been characterized by EPR and magnetic susceptibility measurements, and to a lesser extent by Raman spectroscopy and RBS. The semiconductors were studied using thin films of silicon doped with rare earth metals, e.g. erbium and gadolinium, which had their magnetic properties studied. Using these studies we could determine the state of valence of the rare earths as well as their concentrations in the silicon matrix. According to our results, the valence of the rare earth metal ions is 3+, and we were able to conclude that 4f electronic shells could not be used for the calculation of the conducting band in this system. Furthermore, the analysis of the data on the magnetic susceptibility of the Er 3+ ion with cubic crystalline acting field, gave us the opportunity to estimate the overall splitting of their electronic states for the first time. The conducting polymers were studied using samples of poly(3-methylthiophene) doped with ClO 4 - , which show a phase transition in the range of 230 K to 130 K. The electron paramagnetic resonance also gives important information on the crystallization, doping level and the presence of polarons or bipolarons in conducting polymers. (author)

  18. Solution-mediated cladding doping of commercial polymer optical fibers

    Science.gov (United States)

    Stajanca, Pavol; Topolniak, Ievgeniia; Pötschke, Samuel; Krebber, Katerina

    2018-03-01

    Solution doping of commercial polymethyl methacrylate (PMMA) polymer optical fibers (POFs) is presented as a novel approach for preparation of custom cladding-doped POFs (CD-POFs). The presented method is based on a solution-mediated diffusion of dopant molecules into the fiber cladding upon soaking of POFs in a methanol-dopant solution. The method was tested on three different commercial POFs using Rhodamine B as a fluorescent dopant. The dynamics of the diffusion process was studied in order to optimize the doping procedure in terms of selection of the most suitable POF, doping time and conditions. Using the optimized procedure, longer segment of fluorescent CD-POF was prepared and its performance was characterized. Fiber's potential for sensing and illumination applications was demonstrated and discussed. The proposed method represents a simple and cheap way for fabrication of custom, short to medium length CD-POFs with various dopants.

  19. Extension of the segment-based Wilson and NRTL models for correlation of excess molar enthalpies of polymer solutions

    International Nuclear Information System (INIS)

    Sadeghi, Rahmat

    2005-01-01

    The polymer Wilson model and the polymer NRTL model have been extended for the representation of the excess enthalpy of multicomponent polymer solutions. Applicability of obtained equations in the correlation of the excess enthalpies of polymer solutions has been examined. It is found that the both models are suitable models in representing the published excess enthalpy data for the tested polymer solutions

  20. Solution-processed small molecule-polymer blend organic thin-film transistors with hole mobility greater than 5 cm 2/Vs

    KAUST Repository

    Smith, Jeremy N.

    2012-04-10

    Using phase-separated organic semiconducting blends containing a small molecule, as the hole transporting material, and a conjugated amorphous polymer, as the binder material, we demonstrate solution-processed organic thin-film transistors with superior performance characteristics that include; hole mobility >5 cm 2/Vs, current on/off ratio ≥10 6 and narrow transistor parameter spread. These exceptional characteristics are attributed to the electronic properties of the binder polymer and the advantageous nanomorphology of the blend film. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Solution-processed small molecule-polymer blend organic thin-film transistors with hole mobility greater than 5 cm 2/Vs

    KAUST Repository

    Smith, Jeremy N.; Zhang, Weimin; Sougrat, Rachid; Zhao, Kui; Li, Ruipeng; Cha, Dong Kyu; Amassian, Aram; Heeney, Martin J.; McCulloch, Iain A.; Anthopoulos, Thomas D.

    2012-01-01

    Using phase-separated organic semiconducting blends containing a small molecule, as the hole transporting material, and a conjugated amorphous polymer, as the binder material, we demonstrate solution-processed organic thin-film transistors with superior performance characteristics that include; hole mobility >5 cm 2/Vs, current on/off ratio ≥10 6 and narrow transistor parameter spread. These exceptional characteristics are attributed to the electronic properties of the binder polymer and the advantageous nanomorphology of the blend film. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Monolithic amorphous silicon modules on continuous polymer substrate. Final subcontract report, 9 January 1991--14 April 1991

    Energy Technology Data Exchange (ETDEWEB)

    Grimmer, D.P. [Iowa Thin Film Technologies, Inc., Ames, IA (US)

    1992-03-01

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

  3. Phase transitions of single polymer chains and of polymer solutions: insights from Monte Carlo simulations

    International Nuclear Information System (INIS)

    Binder, K; Paul, W; Strauch, T; Rampf, F; Ivanov, V; Luettmer-Strathmann, J

    2008-01-01

    The statistical mechanics of flexible and semiflexible macromolecules is distinct from that of small molecule systems, since the thermodynamic limit can also be approached when the number of (effective) monomers of a single chain (realizable by a polymer solution in the dilute limit) is approaching infinity. One can introduce effective attractive interactions into a simulation model for a single chain such that a swollen coil contracts when the temperature is reduced, until excluded volume interactions are effectively canceled by attractive forces, and the chain conformation becomes almost Gaussian at the theta point. This state corresponds to a tricritical point, as the renormalization group theory shows. Below the theta temperature a fluid globule is predicted (at nonzero concentration then phase separation between dilute and semidilute solutions occurs), while at still lower temperature a transition to a solid phase (crystal or glass) occurs. Monte Carlo simulations have shown, however, that the fluid globule phase may become suppressed, when the range of the effective attractive forces becomes too short, with the result that a direct (ultimately first-order) transition from the swollen coil to the solid occurs. This behavior is analogous to the behavior of colloidal particles with a very short range of attractive forces, where liquid-vapor-type phase separation may be suppressed. Analogous first-order transitions from swollen coils to dense rodlike or toroidal structures occur for semiflexible polymers. Finally, the modifications of the behavior discussed when the polymers are adsorbed at surfaces are also mentioned, and possible relations to wetting behavior of polymer solutions are addressed.

  4. X-ray small angle scattering of polymer solutions

    International Nuclear Information System (INIS)

    Koyama, Ryuzo

    1975-01-01

    In recent papers, the calculated results were reported on the angular dependence of the intensity of scattered light or X-ray by chain polymers, on the basis of a stiff chain model. As the results, the curves of S 2 P (theta) corresponding to Kratky plot, for different molecular expansion, showed a plateau, and the height of the plateau was proportional to the inverse of molecular expansion coefficient α 2 . But as seen later, there is some possibility that the assumption made in the calculation overestimated the expansion of small segments which theoretically determines scattering curves at large scattering angles, such as the plateau. Accordingly, modified calculation was carried out by adopting the stiff chain polymer model as the previous case. When the contour length of a chain segment is very long, it can be treated approximately as a Gaussian coil, thus the equation for a chain segment expansion coefficient α (t) was obtained. Then the mean square distance of chain segments of polymer molecules was able to be determined, and the equation for a particle scattering factor P(theta) was obtained. The numerical calculation of P(theta) showed that this modified assumption considerably decreased the effect of molecular expansion on P(theta), and the curves of S 2 P(theta) increased monotonously without showing the plateau. The result of this calculation was compared with the experimental curves of polystyrene-toluene solution, and the agreement better than before was obtained. (Kako, I.)

  5. Study of the dosimetric properties using organometallic polymers in solution

    International Nuclear Information System (INIS)

    Fernandes, David Moreira

    2012-01-01

    This work aimed to study the dosimetric characteristics of the polymer of the polymer ''poly-[ 1, l-bis (ethynyl) -4,4-biphenyl (bis-tributylphosphine) Pt (11)]'' (Pt-DEBP) compared to radiation gamma. The Pt-DEBP polymer, containing ten monomer units, was then dissolved in organic solvents as chloroform and toluene. The samples were irradiated at four concentrations (0.0500, 0.0375, 0.0250, 0.0113 mg / mL) in duplicate, with radiation doses ranging from 1 to 90 Gy. The results were evaluated based on spectroscopic techniques such as optical absorption spectroscopy (UV -Vis), fluorescence (emission), time resolved fluorescence (FRT) and Fourier transform infrared (FTIR). For DEBP-Pt solutions in chloroform, there is a shift in the position of the main optical absorption band (πt - π*) to lower wavelength (blue-shift), allied to a decreasing absorption intensity with increasing radiation dose. In fluorescence spectroscopy, there was a shift to longer wavelengths (redshift) allied to an increasing emission intensity with increasing radiation dose. FRT experiments on irradiated samples dissolved in chloroform indicated the presence of a new emitter center. FTIR spectra show the incorporation of chlorine in the polymer chain, justifying the blue-shift observed in the absorption spectra and the new emission center. In addition, the behavior of linear results in the absorption and fluorescence studies was investigated based on the relationship between the wavelength of maximum absorption/emission and the radiation dose. For both cases, a linear behavior was observed in relation to the sample concentration. Repeatability and stability tests were also performed. For the samples dissolved in toluene, there was no significant shift of the spectrum of absorption or fluorescence for all doses. The results show that the Pt-DEBP polymer dissolved in chloroform can be used as a dosimeter for x-ray doses between 1 - 30 Gy based on the changes in absorption and/or emission

  6. Turbulent structures of non-Newtonian solutions containing rigid polymers

    Science.gov (United States)

    Mohammadtabar, M.; Sanders, R. S.; Ghaemi, S.

    2017-10-01

    The turbulent structure of a channel flow of Xanthan Gum (XG) polymer solution is experimentally investigated and compared with water flow at a Reynolds number of Re = 7200 (based on channel height and properties of water) and Reτ = 220 (based on channel height and friction velocity, uτ0). The polymer concentration is varied from 75, 100, and 125 ppm to reach the point of maximum drag reduction (MDR). Measurements are carried out using high-resolution, two-component Particle Image Velocimetry (PIV) to capture the inner and outer layer turbulence. The measurements showed that the logarithmic layer shifts away from the wall with increasing polymer concentration. The slopes of the mean velocity profile for flows containing 100 and 125 ppm XG are greater than that measured for XG at 75 ppm, which is parallel with the slope obtained for deionized water. The increase in slope results in thickening buffer layer. At MDR, the streamwise Reynolds stresses are as large as those of the Newtonian flow while the wall-normal Reynolds stresses and Reynolds shear stresses are significantly attenuated. The sweep-dominated region in the immediate vicinity of the wall extends further from the wall with increasing polymer concentration. The near-wall skewness intensifies towards positive streamwise fluctuations and covers a larger wall-normal length at larger drag reduction values. The quadrant analysis at y + 0 = 25 shows that the addition of polymers inclines the principal axis of v versus u plot to almost zero (horizontal) as the joint probability density function of fluctuations becomes symmetric with respect to the u axis at MDR. The reduction of turbulence production is mainly associated with the attenuation of the ejection motions. The spatial-correlation of the fluctuating velocity field shows that increasing the polymer concentration increases the spatial coherence of u fluctuations in the streamwise direction while they appear to have the opposite effect in the wall

  7. Suppression of persistent photo-conductance in solution-processed amorphous oxide thin-film transistors

    Science.gov (United States)

    Lee, Minkyung; Kim, Minho; Jo, Jeong-Wan; Park, Sung Kyu; Kim, Yong-Hoon

    2018-01-01

    This study offers a combinatorial approach for suppressing the persistent photo-conductance (PPC) characteristic in solution-processed amorphous oxide semiconductor (AOS) thin-film transistors (TFTs) in order to achieve rapid photo-recovery. Various analyses were used to examine the photo-instability of indium-gallium-zinc-oxide (IGZO) TFTs including negative-bias-illumination-stress (NBIS) and transient photo-response behaviors. It was found that the indium ratio in metallic components had a significant impact on their PPC and photo-recovery characteristics. In particular, when the indium ratio was low (51.5%), the PPC characteristic was significantly suppressed and achieving rapid photo-recovery was possible without significantly affecting the electrical performance of AOSs. These results imply that the optimization of the indium composition ratio may allow achieving highly photo-stable and near PPC-free characteristics while maintaining high electrical performance of AOSs. It is considered that the negligible PPC behavior and rapid photo-recovery observed in IGZO TFTs with a lower indium composition are attributed to the less activation energy required for the neutralization of ionized oxygen vacancies.

  8. Perovskite/polymer solar cells prepared using solution process

    International Nuclear Information System (INIS)

    Rosa, E. S.; Shobih; Nursam, N. M.; Saputri, D. G.

    2016-01-01

    We report a simple solution-based process to fabricate a perovskite/polymer tandem solar cell using inorganic CH 3 NH 3 PM 3 as an absorber and organic PCBM (6,6 phenyl C61- butyric acid methyl ester) as an electron transport layer. The absorber solution was prepared by mixing the CH 3 NH 3 I (methyl ammonium iodide) with PbI 2 (lead iodide) in DMF (N,N- dimethyl formamide) solvent. The absorber and electron transport layer were deposited by spin coating method. The electrical characteristics generated from the cell under 50 mW/cm 2 at 25 °C comprised of an open circuit voltage of 0. 3 1 V, a short circuit current density of 2.53 mA/cm 2 , and a power conversion efficiency of 0.42%. (paper)

  9. Understanding Interfacial Alignment in Solution Coated Conjugated Polymer Thin Films

    International Nuclear Information System (INIS)

    Qu, Ge; Zhao, Xikang; Newbloom, Gregory M.; Zhang, Fengjiao; Mohammadi, Erfan

    2017-01-01

    Domain alignment in conjugated polymer thin films can significantly enhance charge carrier mobility. However, the alignment mechanism during meniscus-guided solution coating remains unclear. Furthermore, interfacial alignment has been rarely studied despite its direct relevance and critical importance to charge transport. In this study, we uncover a significantly higher degree of alignment at the top interface of solution coated thin films, using a donor–acceptor conjugated polymer, poly(diketopyrrolopyrrole-co-thiopheneco- thieno[3,2-b]thiophene-co-thiophene) (DPP2T-TT), as the model system. At the molecular level, we observe in-plane π–π stacking anisotropy of up to 4.8 near the top interface with the polymer backbone aligned parallel to the coating direction. The bulk of the film is only weakly aligned with the backbone oriented transverse to coating. At the mesoscale, we observe a well-defined fibril-like morphology at the top interface with the fibril long axis pointing toward the coating direction. Significantly smaller fibrils with poor orientational order are found on the bottom interface, weakly aligned orthogonal to the fibrils on the top interface. The high degree of alignment at the top interface leads to a charge transport anisotropy of up to 5.4 compared to an anisotropy close to 1 on the bottom interface. We attribute the formation of distinct interfacial morphology to the skin-layer formation associated with high Peclet number, which promotes crystallization on the top interface while suppressing it in the bulk. As a result, we further infer that the interfacial fibril alignment is driven by the extensional flow on the top interface arisen from increasing solvent evaporation rate closer to the meniscus front.

  10. Hot Melt Extruded Amorphous Solid Dispersion of Posaconazole with Improved Bioavailability: Investigating Drug-Polymer Miscibility with Advanced Characterisation

    Directory of Open Access Journals (Sweden)

    Ritesh Fule

    2014-01-01

    Full Text Available Invasive antifungal infections are reasons for morbidity and mortality in immunogenic patients worldwide. Posaconazole is a most promising antifungal agent against all types of invasive infections with high % of cure rate. The marketed suspension formulation has low bioavailability and is needed to be taken with food. In this paper, PCZ hot melt extruded amorphous solid dispersion (SD with immediate release and improved bioavailability was prepared using Soluplus (Sol as primary carrier for solubilization. Surfactants such as PEG 400, Lutrol F27, Lutrol F68, and TPGS are also used in combination with Soluplus to improve the physicochemical performance of the formulation when it comes in contact with GI (gastrointestinal fluid. Drug-polymer miscibility of SD was investigated using advanced techniques. In the in vivo study, the AUC(0–72 and Cmax of PCZ/Soluplus were 11.5 and 11.74 time higher than those of pure PCZ. The formulation of the extrudate SD had an AUC(0–72 and Cmax higher than those with the commercial capsule (Noxafil. Molecular dynamic (MD simulation studies were carried out using in silico molecular modelling to understand the drug-polymer intermolecular behaviour. The results of this research ensure enhanced dissolution and bioavailability of the solid dispersion of PCZ prepared by HME compared with the PCZ suspension.

  11. The Specific Refractive Index Increments for POSS Polymers in Solution

    National Research Council Canada - National Science Library

    Largo, Sheryl

    2004-01-01

    Partial contents: Hybrid Inorganic/Organic Polymers, Introduction to POSS, Anatomy of a POSS Nanostructure, POSS Polymer Incorporation, POSS Styrene Monomer Synthesis, POSS Styrene Copolymer Synthesis, 1HNMR...

  12. Reduced viscosity for flagella moving in a solution of long polymer chains

    Science.gov (United States)

    Zhang, Yuchen; Li, Gaojin; Ardekani, Arezoo M.

    2018-02-01

    The bacterial flagellum thickness is smaller than the radius of gyration of long polymer chain molecules. The flow velocity gradient over the length of polymer chains can be nonuniform and continuum models of polymeric liquids break in this limit. In this work, we use Brownian dynamics simulations to study a rotating helical flagellum in a polymer solution and overcome this limitation. As the polymer size increases, the viscosity experienced by the flagellum asymptotically reduces to the solvent viscosity. The contribution of polymer molecules to the local viscosity in a solution of long polymer chains decreases with the inverse of polymer size to the power 1/2. The difference in viscosity experienced by the bacterial cell body and flagella can predict the nonmonotonic swimming speed of bacteria in polymer solutions.

  13. Development of amorphous dispersions of artemether with hydrophilic polymers via spray drying: Physicochemical and in silico studies

    Directory of Open Access Journals (Sweden)

    Jaywant N. Pawar

    2016-06-01

    Full Text Available Artemether (ARM is a poorly water soluble and poorly permeable drug effective against acute and severe falciparum malaria, hence there is a strong need to improve its solubility. The objective of the study was to enhance the solubility and dissolution rate of ARM by preparation of solid dispersions using spray-drying technique. Solid dispersions of ARM were prepared with Soluplus, Kollidon VA 64, HPMC and Eudragit EPO at weight ratios of 1:1, 1:2, 1:3 using spray drying technology, and characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry (DSC, and X-ray powder diffraction (XRD to identify the physicochemical interaction between drug and carrier, as well as effect on dissolution. The prepared solid dispersion of ARM with polymers showed reduced crystallinity as compared to neat ARM, which was confirmed by DSC and XRD. Drug/polymer interactions were studied in-silico by docking and molecular dynamics which indicated formation of van der Waals type of interactions of ARM with the polymers. Based on solubility studies, the optimum drug/Soluplus ratio was found to be 1:3. The dissolution studies of formulation SD3 showed highest drug release up to 82% compared to neat ARM giving only 20% at 60 minutes. The spray-dried products were free of crystalline ARM; possessed higher dissolution rates, and were stable over a period according to ICH guidelines. These findings suggest that an amorphous solid dispersion of ARM could be a viable option for enhancing the dissolution rate of ARM.

  14. The relation between relaxed enthalpy and volume during physical aging of amorphous polymers and selenium

    Czech Academy of Sciences Publication Activity Database

    Slobodian, P.; Říha, Pavel; Rychwalski, R. W.; Emri, I.; Sáha, P.; Kubát, J.

    2006-01-01

    Roč. 42, č. 10 (2006), s. 2824-2837 ISSN 0014-3057 R&D Projects: GA AV ČR IAA2060401 Institutional research plan: CEZ:AV0Z20600510 Keywords : Enthalpy relaxation * Polymer aging Subject RIV: BJ - Thermodynamics Impact factor: 2.113, year: 2006

  15. Comparison of acidic polymers for the removal of cobalt from water solutions by polymer assisted ultrafiltration

    Energy Technology Data Exchange (ETDEWEB)

    Dambies, Laurent, E-mail: chemjobs@netcourrir.com [Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw (Poland); Jaworska, Agnieszka, E-mail: a.jaworska@ichtj.waw.pl [Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw (Poland); Zakrzewska-Trznadel, Grazyna; Sartowska, Bozena [Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw (Poland)

    2010-06-15

    In this study, three sulfonated water-soluble polymers based on poly(vinyl alcohol) of different molecular weights (10,000, 50,000 and 100,000 Da) were prepared and tested against commercially available poly(acrylic acid) for the removal of cobalt using polymer assisted ultrafiltration. High rejection rates were obtained between pH 3 and 6 with sulfonated poly(vinyl alcohol) (PVA 10,000 and 50,000 Da) whereas poly(acrylic acid) (PAA) of similar molecular weights performed rather poorly in this pH range. Sulfonation improved significantly sorption capability of PVA. Sulfonated PVA 10,000 was the best complexing agent with rejection rate above 95% between pH 3 and 6. For unmodified PVA the rejection rate was only 30-45% at pH 6 and there was no rejection at pH 3 at all. PAA rejection rate was above 90% at pH 6 and only about 10% at pH 3. Large scale experiment in cross-flow, continuous apparatus conducted by using PVA-SO{sub 3}H 10,000 Da to remove {sup 60}Co radioisotope from water solutions showed excellent results demonstrating the potential of this polymer to purify acidic radioactive wastes containing cobalt radioisotopes.

  16. Chemical metallization of KMPR photoresist polymer in aqueous solutions

    Science.gov (United States)

    Zeb, Gul; Duong, Xuan Truong; Vu, Ngoc Pi; Phan, Quang The; Nguyen, Duc Tuong; Ly, Viet Anh; Salimy, Siamak; Le, Xuan Tuan

    2017-06-01

    While conventional methods for preparing thin films of metals and metallic alloys on insulating substrates in the field of microelectromechanical systems (MEMS) include vapor deposition techniques, we demonstrate here that electroless deposition can be considered as an alternate efficient approach to metallize the surface of insulating substrates, such as KMPR epoxy photoresist polymer. In comparison with the physical and chemical vapor deposition methods, which are well-established for metallization of photoresist polymers, our electroless nickel plating requires only immersing the substrates into aqueous solutions in open air at low temperatures. Thin films of nickel alloy have been deposited electrolessly on KMPR surface, through a cost-effective and environmental chromium-free process, mediated through direct grafting of amine palladium complexes in aqueous medium. This covalent organic coating provides excellent adhesion between KMPR and the nickel film and allows better control of the palladium catalyst content. Covalent grafting and characterization of the deposited nickel film have been carried out by means of Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy techniques.

  17. A ‘frozen volume’ transition model and working mechanism for the shape memory effect in amorphous polymers

    Science.gov (United States)

    Lu, Haibao; Wang, Xiaodong; Yao, Yongtao; Qing Fu, Yong

    2018-06-01

    Phenomenological models based on frozen volume parameters could well predict shape recovery behavior of shape memory polymers (SMPs), but the physical meaning of using the frozen volume parameters to describe thermomechanical properties has not been well-established. In this study, the fundamental working mechanisms of the shape memory effect (SME) in amorphous SMPs, whose temperature-dependent viscoelastic behavior follows the Eyring equation, have been established with the considerations of both internal stress and its resulted frozen volume. The stress-strain constitutive relation was initially modeled to quantitatively describe effects of internal stresses at the macromolecular scale based on the transient network theory. A phenomenological ‘frozen volume’ model was then established to characterize the macromolecule structure and SME of amorphous SMPs based on a two-site stress-relaxation model. Effects of the internal stress, frozen volume and strain rate on shape memory behavior and thermomechanical properties of the SMP were investigated. Finally, the simulation results were compared with the experimental results reported in the literature, and good agreements between the theoretical and experimental results were achieved. The novelty and key differences of our newly proposed model with respect to the previous reports are (1). The ‘frozen volume’ in our study is caused by the internal stress and governed by the two-site model theory, thus has a good physical meaning. (2). The model can be applied to characterize and predict both the thermal and thermomechanical behaviors of SMPs based on the constitutive relationship with internal stress parameters. It is expected to provide a power tool to investigate the thermomechanical behavior of the SMPs, of which both the macromolecular structure characteristics and SME could be predicted using this ‘frozen volume’ model.

  18. Microscopic theory of light-induced deformation in amorphous side-chain azobenzene polymers.

    Science.gov (United States)

    Toshchevikov, V; Saphiannikova, M; Heinrich, G

    2009-04-16

    We propose a microscopic theory of light-induced deformation of side-chain azobenzene polymers taking into account the internal structure of polymer chains. Our theory is based on the fact that interaction of chromophores with the polarized light leads to the orientation anisotropy of azobenzene macromolecules which is accompanied by the appearance of mechanical stress. It is the first microscopic theory which provides the value of the light-induced stress larger than the yield stress. This result explains a possibility for the inscription of surface relief gratings in glassy side-chain azobenzene polymers. For some chemical architectures, elongation of a sample demonstrates a nonmonotonic behavior with the light intensity and can change its sign (a stretched sample starts to be uniaxially compressed), in agreement with experiments. Using a viscoplastic approach, we show that the irreversible strain of a sample, which remains after the light is switched off, decreases with increasing temperature and can disappear at certain temperature below the glass transition temperature. This theoretical prediction is also confirmed by recent experiments.

  19. Study of the flow development of polymer solutions through capillaries

    International Nuclear Information System (INIS)

    Perez-Gonzalez, J.; De Vargas, L.; Tejero, M.

    1991-01-01

    Flow experiments through capillaries with semirigid and rigid polymers in aqueous solutions were carried out in order to study the dependence of the flow development on the molecular conformation and the length to diameter ratio (L/D), of the capillary at relatively low shear rates. It was found that the apparent viscosity has a strong dependence upon the ratio L/D for a given shear rate, although an asymptotic value is reached. This dependence was reflected in the non-linearity of Bagley's plots. The asymptotic value was attained at lower L/D values for semirigid molecules than for rigid ones, showing the influence of the molecular conformation on the flow field development due to the different modes of relaxation for each type of molecule. (Author)

  20. Flow induced/ refined solution crystallization of a semiconducting polymer

    Science.gov (United States)

    Nguyen, Ngoc A.

    Organic photovoltaics, a new generation of solar cells, has gained scientific and economic interests due to the ability of solution-processing and potentially low-cost power production. Though, the low power conversion efficiency of organic/ plastic solar cells is one of the most pertinent challenges that has appealed to research communities from many different fields including materials science and engineering, electrical engineering, chemical engineering, physics and chemistry. This thesis focuses on investigating and controlling the morphology of a semi-conducting, semi-crystalline polymer formed under shear-flow. Molecular structures and processing techniques are critical factors that significantly affect the morphology formation in the plastic solar cells, thus influencing device performance. In this study, flow-induced solution crystallization of poly (3-hexylthiophene) (P3HT) in a poor solvent, 2-ethylnapthalene (2-EN) was utilized to make a paint-like, structural liquid. The polymer crystals observed in this structured paint are micrometers long, nanometers in cross section and have a structure similar to that formed under quiescent conditions. There is pi-pi stacking order along the fibril axis, while polymer chain folding occurs along the fibril width and the order of the side-chain stacking is along fibril height. It was revealed that shear-flow not only induces P3HT crystallization from solution, but also refines and perfects the P3HT crystals. Thus, a general strategy to refine the semiconducting polymer crystals from solution under shear-flow has been developed and employed by simply tuning the processing (shearing) conditions with respect to the dissolution temperature of P3HT in 2-EN. The experimental results demonstrated that shear removes defects and allows more perfect crystals to be formed. There is no glass transition temperature observed in the crystals formed using the flow-induced crystallization indicating a significantly different

  1. 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...

  2. Fabrication of amorphous silica nanowires via oxygen plasma treatment of polymers on silicon

    Science.gov (United States)

    Chen, Zhuojie; She, Didi; Chen, Qinghua; Li, Yanmei; Wu, Wengang

    2018-02-01

    We demonstrate a facile non-catalytic method of fabricating silica nanowires at room temperature. Different polymers including photoresists, parylene C and polystyrene are patterned into pedestals on the silicon substrates. The silica nanowires are obtained via the oxygen plasma treatment on those pedestals. Compared to traditional strategies of silica nanowire fabrication, this method is much simpler and low-cost. Through designing the proper initial patterns and plasma process parameters, the method can be used to fabricate various regiment nano-scale silica structure arrays in any laboratory with a regular oxygen-plasma-based cleaner or reactive-ion-etching equipment.

  3. Artificial Neural Network Model to Estimate the Viscosity of Polymer Solutions for Enhanced Oil Recovery

    Directory of Open Access Journals (Sweden)

    Pan-Sang Kang

    2016-06-01

    Full Text Available Polymer flooding is now considered a technically- and commercially-proven method for enhanced oil recovery (EOR. The viscosity of the injected polymer solution is the key property for successful polymer flooding. Given that the viscosity of a polymer solution has a non-linear relationship with various influential parameters (molecular weight, degree of hydrolysis, polymer concentration, cation concentration of polymer solution, shear rate, temperature and that measurement of viscosity based on these parameters is a time-consuming process, the range of solution samples and the measurement conditions need to be limited and precise. Viscosity estimation of the polymer solution is effective for these purposes. An artificial neural network (ANN was applied to the viscosity estimation of FlopaamTM 3330S, FlopaamTM 3630S and AN-125 solutions, three commonly-used EOR polymers. The viscosities measured and estimated by ANN and the Carreau model using Lee’s correlation, the only method for estimating the viscosity of an EOR polymer solution in unmeasured conditions, were compared. Estimation accuracy was evaluated by the average absolute relative deviation, which has been widely used for accuracy evaluation of the results of ANN models. In all conditions, the accuracy of the ANN model is higher than that of the Carreau model using Lee’s correlation.

  4. Localized solid-state amorphization at grain boundaries in a nanocrystalline Al solid solution subjected to surface mechanical attrition

    Energy Technology Data Exchange (ETDEWEB)

    Wu, X [State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080 (China); Tao, N [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Hong, Y [State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080 (China); Lu, J [LASMIS, University of Technology of Troyes, 10000, Troyes (France); Lu, K [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

    2005-11-21

    Using high-resolution electron microscopy, localized solid-state amorphization (SSA) was observed in a nanocrystalline (NC) Al solid solution (weight per cent 4.2 Cu, 0.3 Mn, the rest being Al) subjected to a surface mechanical attrition treatment. It was found that the deformation-induced SSA may occur at the grain boundary (GB) where either the high density dislocations or dislocation complexes are present. It is suggested that lattice instability due to elastic distortion within the dislocation core region plays a significant role in the initiation of the localized SSA at defective sites. Meanwhile, the GB of severely deformed NC grains exhibits a continuously varying atomic structure in such a way that while most of the GB is ordered but reveals corrugated configurations, localized amorphization may occur along the same GB.

  5. Influence of complexing on physicochemical properties of polymer-salt solutions

    International Nuclear Information System (INIS)

    Ostroushko, A.A.; Yushkova, S.M.; Koridze, N.V.; Skobkoreva, N.V.; Zhuravleva, L.I.; Palitskaya, T.A.; Antropova, S.V.; Ostroushko, I.P.; AN SSSR, Moscow

    1993-01-01

    Using the methods of spectrophotometry, viscosimetry, conductometry the influence of salt-polymer complexing processes on physicochemical prperties of aqueous solutions of yttrium, barium, copper nitrates and formates with polyvinyl alcohol was studied. Change of dynamic viscosity, specific electric conductivity of solutions in the process of complexing was shown. Thermal effects of salt-polymer interaction were measured. It is shown that decrease of transition temperature of polymer to plastic state in films, temperature and effective activation energy of salt decomposition is also connected with complexing. Effective values of surface tension on the boundary with air are measured. Coefficients of cation diffusion in polymer-salt solutions are estimated

  6. Side Chain Engineering in Solution-Processable Conjugated Polymers

    KAUST Repository

    Mei, Jianguo; Bao, Zhenan

    2014-01-01

    Side chains in conjugated polymers have been primarily utilized as solubilizing groups. However, these side chains have roles that are far beyond. We advocate using side chain engineering to tune a polymer's physical properties, including absorption

  7. Sustainability of silver nanoparticles in solutions and polymer materials

    International Nuclear Information System (INIS)

    Khaydarov, R.R.; Malikov, Sh.; Khaydarov, R.A.; Mironov, V.V.

    2006-01-01

    The technology of obtaining stable silver nanoparticles in solutions and composite materials for attainment of antimicrobial and antifungal properties to different surfaces has been developed. The shape of particles is spherical, diameter is about 5 nm. Various concentrations of silver nanoparticles have been deposited onto surfaces of different materials (cotton and synthetic fabrics, fibroid sorbents and polymer materials). Different ways of treatment and densities of nanoparticles on the treated surface have been studied during 6 months with respect to the best sustainability. In order to prevent agglomeration of obtained metal nanoparticles on the surface of materials treated, stabilizing reagents (ethylene glycol, formic acid, sodium dodecyl sulphate, etc.) have been used and their relative efficacy has been examined. Residual concentrations of the nanoparticles on various fabrics after 1, 3, 5 and 10 cycles of washing have been also studied. The treated fabrics keep their antibacterial properties after at least 3 times of laundering. The best finishing process to attach silver nanoparticles combination to various materials has been compared with biocidal properties of such antibacterial agents as metal salt solutions and zinc pyrithione.The possibility of treatment of nuclear track membranes by silver nanoparticles in order to prevent microbial growth on the surface of membranes has been discussed. (author)

  8. Electrostatics of polymer translocation events in electrolyte solutions.

    Science.gov (United States)

    Buyukdagli, Sahin; Ala-Nissila, T

    2016-07-07

    We develop an analytical theory that accounts for the image and surface charge interactions between a charged dielectric membrane and a DNA molecule translocating through the membrane. Translocation events through neutral carbon-based membranes are driven by a competition between the repulsive DNA-image-charge interactions and the attractive coupling between the DNA segments on the trans and the cis sides of the membrane. The latter effect is induced by the reduction of the coupling by the dielectric membrane. In strong salt solutions where the repulsive image-charge effects dominate the attractive trans-cis coupling, the DNA molecule encounters a translocation barrier of ≈10 kBT. In dilute electrolytes, the trans-cis coupling takes over image-charge forces and the membrane becomes a metastable attraction point that can trap translocating polymers over long time intervals. This mechanism can be used in translocation experiments in order to control DNA motion by tuning the salt concentration of the solution.

  9. Metallic glasses: viable tool materials for the production of surface microstructures in amorphous polymers by micro-hot-embossing

    International Nuclear Information System (INIS)

    Henann, David L; Srivastava, Vikas; Taylor, Hayden K; Hale, Melinda R; Hardt, David E; Anand, Lallit

    2009-01-01

    Metallic glasses possess unique mechanical properties which make them attractive materials for fabricating components for a variety of applications. For example, the commercial Zr-based metallic glasses possess high tensile strengths (≈2.0 GPa), good fracture toughnesses (≈10–50 MPa√m) and good wear and corrosion resistances. A particularly important characteristic of metallic glasses is their intrinsic homogeneity to the nanoscale because of the absence of grain boundaries. This characteristic, coupled with their unique mechanical properties, makes them ideal materials for fabricating micron-scale components, or high-aspect-ratio micro-patterned surfaces, which may in turn be used as dies for the hot-embossing of polymeric microfluidic devices. In this paper we consider a commercially available Zr-based metallic glass which has a glass transition temperature of T g ≈ 350 °C and describe the thermoplastic forming of a tool made from this material, which has the (negative) microchannel pattern for a simple microfluidic device. This tool was successfully used to produce the microchannel pattern by micro-hot-embossing of the amorphous polymers poly(methyl methacrylate) (T g ≈ 115 °C) and Zeonex-690R (T g ≈ 136 °C) above their glass transition temperatures. The metallic glass tool was found to be very robust, and it was used to produce hundreds of high-fidelity micron-scale embossed patterns without degradation or failure

  10. Role of Molecular Interactions for Synergistic Precipitation Inhibition of Poorly Soluble Drug in Supersaturated Drug-Polymer-Polymer Ternary Solution.

    Science.gov (United States)

    Prasad, Dev; Chauhan, Harsh; Atef, Eman

    2016-03-07

    We are reporting a synergistic effect of combined Eudragit E100 and PVP K90 in precipitation inhibition of indomethacin (IND) in solutions at low polymer concentration, a phenomenon that has significant implications on the usefulness of developing novel ternary solid dispersion of poorly soluble drugs. The IND supersaturation was created by cosolvent technique, and the precipitation studies were performed in the absence and the presence of individual and combined PVP K90 and Eudragit E100. The studies were also done with PEG 8000 as a noninteracting control polymer. A continuous UV recording of the IND absorption was used to observe changes in the drug concentration over time. The polymorphic form and morphology of precipitated IND were characterized by Raman spectroscopy and scanning electron microscopy. The change in the chemical shift in solution (1)H NMR was used as novel approach to probe IND-polymer interactions. Molecular modeling was used for calculating binding energy between IND-polymer as another indication of IND-polymer interaction. Spontaneous IND precipitation was observed in the absence of polymers. Eudragit E100 showed significant inhibitory effect on nuclei formation due to stronger interaction as reflected in higher binding energy and greater change in chemical shift by NMR. PVP K90 led to significant crystal growth inhibition due to adsorption on growing IND crystals as confirmed by modified crystal habit of precipitate in the presence of PVP K90. Combination of polymers resulted in a synergistic precipitation inhibition and extended supersaturation. The NMR confirmed interaction between IND-Eudragit E100 and IND-PVP K90 in solution. The combination of polymers showed similar peak shift albeit using lower polymer concentration indicating stronger interactions. The results established the significant synergistic precipitation inhibition effect upon combining Eudragit E100 and PVP K90 due to drug-polymer interaction.

  11. Influence of isotopic disorder on solid state amorphization and polyamorphism in solid H2O -D2O solutions

    Science.gov (United States)

    Gromnitskaya, E. L.; Danilov, I. V.; Lyapin, A. G.; Brazhkin, V. V.

    2015-10-01

    We present a low-temperature and high-pressure ultrasonic study of elastic properties of isotopic H2O-D2O solid solutions, comparing their properties with those of the isotopically pure H2O and D2O ices. Measurements were carried out for solid state amorphization (SSA) from 1h to high-density amorphous (HDA) ice upon compression up to 1.8 GPa at 77 K and for the temperature-induced (77 -190 K ) u-HDA (unrelaxed HDA) → e-HDA (expanded HDA) → low-density amorphous (LDA )→1 c cascade of ice transformations near room pressure. There are many similarities in the elasticity behaviour of H2O ,D2O , and H2O-D2O solid solutions, including the softening of the shear elastic modulus as a precursor of SSA and the HDA →LDA transition. We have found significant isotopic effects during H/D substitution, including elastic softening of H2O -D2O solid solutions with respect to the isotopically pure ices in the case of the bulk moduli of ices 1c and 1h and for both bulk and shear elastic moduli of HDA ice at high pressures (>1 GPa ) . This softening is related to the configurational isotopic disorder in the solid solutions. At low pressures, the isotope concentration dependence of the elastic moduli of u-HDA ice changes remarkably and becomes monotonic with pronounced change of the bulk modulus (≈20 %) .

  12. Small-angle x-ray scattering study on conformation of amorphous polymer chain in the bulk

    International Nuclear Information System (INIS)

    Hayashi, Hisao; Hamada, Fumiyuki; Nakajima, Akio

    1975-01-01

    In a previous paper, the new method for the determination of the conformation of polymer chains in concentrated solution and in bulk by small angle X-ray scattering was reported. The purpose of this paper is to estimate the dimension and conformation of polystyrene chains in bulk by this method. The tagged polymer used was the copolymer of styrene and p-iodostyrene. Excess scattering was obtained by subtracting the intensity of polystyrene matrix from that of a mixture containing polystyrene and a small fraction of the tagged polystyrene. Since the excess scattering originates from the group of iodine atoms in the tagged polystyrene, the radius of gyration of the tagged polystyrene is estimated by Guinier plot. Measurement was made with a Kratky camera, and in order to obtain high scattering intensity, the primary beam with line-shaped cross section was used. The intercepts of two limiting curves in the plotted radius of gyration diagram showed good agreement, and the measured molecular dimension agreed with the unperturbed dimension of this polymer. It was concluded that the molecular chains in bulk are mutually penetrable, and the centers of gravity of the molecules distribute almost randomly. It was suggested from the plot of the excess scattering intensity that the conformation of the tagged molecules is a random coil. The present results did not support the ordered structure revealed by bundle model and meander model. (Kako, I.)

  13. Understanding API-polymer proximities in amorphous stabilized composite drug products using fluorine-carbon 2D HETCOR solid-state NMR.

    Science.gov (United States)

    Abraham, Anuji; Crull, George

    2014-10-06

    A simple and robust method for obtaining fluorine-carbon proximities was established using a (19)F-(13)C heteronuclear correlation (HETCOR) two-dimensional (2D) solid-state nuclear magnetic resonance (ssNMR) experiment under magic-angle spinning (MAS). The method was applied to study a crystalline active pharmaceutical ingredient (API), avagacestat, containing two types of fluorine atoms and its API-polymer composite drug product. These results provide insight into the molecular structure, aid with assigning the carbon resonances, and probe API-polymer proximities in amorphous spray dried dispersions (SDD). This method has an advantage over the commonly used (1)H-(13)C HETCOR because of the large chemical shift dispersion in the fluorine dimension. In the present study, fluorine-carbon distances up to 8 Å were probed, giving insight into the API structure, crystal packing, and assignments. Most importantly, the study demonstrates a method for probing an intimate molecular level contact between an amorphous API and a polymer in an SDD, giving insights into molecular association and understanding of the role of the polymer in API stability (such as recrystallization, degradation, etc.) in such novel composite drug products.

  14. Self and collective dynamics of ordered star polymer solutions

    CERN Document Server

    Stellbrink, J; Monkenbusch, M; Richter, D; Ehlers, G; Schleger, P

    2002-01-01

    We investigated the dynamics of 18-arm polyisoprene star polymer solutions well above their overlap concentration c sup *. Combining neutron spin echo spectroscopy (NSE) and selective H/D labelling, we were able to separate inter- (collective) and intra-star (self) dynamics. Only at low Q-vectors do self and collective dynamics become discernible. Here, collective dynamics are found to be consistent with a colloidal approach resulting from star-star interactions. The collective short time diffusion coefficient D sub e sub f sub f is well described by the term D sub 0 /S(Q), with D sub 0 the diffusion coefficient at infinite dilution. At Q sub m , the peak position in the structure factor S(Q), no difference is observable between collective and self dynamics. For covering the slowed-down dynamics at Q sub m the time range of NSE was extended for the first time up to 350 ns using long wavelengths, lambda=19 A, at IN15 (ILL, Grenoble). We found that S(Q,t)/S(Q,0) relaxes into a concentration-dependent plateau. T...

  15. Shock wave emission from laser-induced cavitation bubbles in polymer solutions.

    Science.gov (United States)

    Brujan, Emil-Alexandru

    2008-09-01

    The role of extensional viscosity on the acoustic emission from laser-induced cavitation bubbles in polymer solutions and near a rigid boundary is investigated by acoustic measurements. The polymer solutions consist of a 0.5% polyacrylamide (PAM) aqueous solution with a strong elastic component and a 0.5% carboxymethylcellulose (CMC) aqueous solution with a weak elastic component. A reduction of the maximum amplitude of the shock wave pressure and a prolongation of the oscillation period of the bubble were found in the elastic PAM solution. It might be caused by an increased resistance to extensional flow which is conferred upon the liquid by the polymer additive. In both polymer solutions, however, the shock pressure decays proportionally to r(-1) with increasing distance r from the emission centre.

  16. Modeling of Dilute Polymer Solutions in Confined Space

    DEFF Research Database (Denmark)

    Wang, Yanwei

    2009-01-01

    This thesis deals with modeling of a polymer chain subject to spatial confinement. The properties of confined macromolecules are both of fundamental interest in polymer physics and of practical importance in a variety of applications including chromatographic separation of polymers, and the use...... of polymers to control the stability of colloidal suspensions. Furthermore, recent advances in micro- and nano-structuring techniques have led to the production of fluidic channels of critical dinlension approaching the molecular scales, in which areas understanding the effects of spatial restrictions...... to macromolecules is critical to the design and application of those devices. Our primary interest is to provide an understanding of the separation principle of polymers in size exclusion chromatography (SEC), where under ideal conditions the polymer concentration is low, and detailed enthalpic interactions...

  17. Evolution of the magnesium incorporated amorphous calcium phosphate to nano-crystallized hydroxyapatite in alkaline solution

    Science.gov (United States)

    Zhang, Xiao-Juan; Lin, Dong-Yang; Yan, Xiao-Hui; Wang, Xiao-Xiang

    2011-12-01

    A homogeneous amorphous calcium phosphate (ACP) coating containing magnesium was achieved on titanium substrates by electrochemical deposition (ECD). Its amorphous structure is confirmed by transmission electron microscope (TEM) together with grazing reflection absorption infrared spectroscopy (IR) spectrometer. In the images of high-resolution transmission electron microscope (HRTEM), the ACP spheres are assembled by nano-particles with the diameter of 5-10 nm. In the alkaline environment, nucleation of hydroxyapatite (HAP) occurs on the surfaces of ACP spheres. By consuming the Ca and PO 4 ions inside the ACP spheres, the HAP nuclei grow outward. Confirmed by TEM, the ACP spheres converse to hollow HAP spheres composed of HAP nano-needles. The coating is finally constructed by the HAP nano-needles, which are themselves aggregated by numerous nano-particles.

  18. Side Chain Engineering in Solution-Processable Conjugated Polymers

    KAUST Repository

    Mei, Jianguo

    2014-01-14

    Side chains in conjugated polymers have been primarily utilized as solubilizing groups. However, these side chains have roles that are far beyond. We advocate using side chain engineering to tune a polymer\\'s physical properties, including absorption, emission, energy level, molecular packing, and charge transport. To date, numerous flexible substituents suitable for constructing side chains have been reported. In this Perspective article, we advocate that the side chain engineering approach can advance better designs for next-generation conjugated polymers. © 2013 American Chemical Society.

  19. Aspects récents de la thermodynamique des solutions de polymères Recent Aspects of the Thermodynamics of Polymer Solutions

    Directory of Open Access Journals (Sweden)

    Dayantis J.

    2006-11-01

    Full Text Available On examine dans cet article différentes approches de la thermodynamique des solutions de polymères placées dans leur contexte historique. On rappelle d'abord le modèle du réseau de Flory-Huggins et on en souligne les déficiences. On traite ensuite brièvement de la mécanique statistique des solutions de polymères introduite par Prigogine en 1957 et on montre qu'elle constitue un progrès qualitatif par rapport à la théorie du réseau, mais qu'elle ne prévoit cependant pas de manière quantitative les propriétés de ces solutions. On montre ensuite que le concept de volume libre, qui permet un traitement simplifié de certaines quantités, permet également d'expliquer tout naturellement l'existence d'une deuxième température de séparation en phase lorsque l'on élève la température, propriété qui différencie les solutions de polymères des mélanges de liquidés simples. Enfin, dans une dernière partie, on mentionne brièvement les travaux récents de l'École de Paris, qui traite les solutions de polymères par analogie avec les transitions magnétiques. This article examines différent approaches ta the thermodynamics of polymer solutions set in their historical context. First of all, the Flory-Huggins network model is described and ifs deficiencies are pointed out. Then attention is briefly drawn to the statistical mechanics of polymer solutions as introduced by Prigogine in 1957, and this mechanics is shown to be a qualitative advance compared with the network theory, but it nonetheless does not quantitatively predict the properties of such solutions. It is then shown that the concept of free volume, enabling some quantifies to be treated in a simplified way, also serves to provide a quite natural explanation for the existence of a second phase separation temperature when the temperature is raised, i. e. a property that differentiates polymer solutions from simple liquid mixtures. In the final part, brief mention is made

  20. Toward a Mesoscale Model for the Dynamics of Polymer Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Miller, G H; Trebotich, D

    2006-10-02

    To model entire microfluidic systems containing solvated polymers we argue that it is necessary to have a numerical stability constraint governed only by the advective CFL condition. Advancements in the treatment of Kramers bead-rod polymer models are presented to enable tightly-coupled fluid-particle algorithms in the context of system-level modeling.

  1. Solution electrospinning of particle-polymer composite fibres

    DEFF Research Database (Denmark)

    Christiansen, Lasse; Fojan, Peter

    2016-01-01

    -scale, is produced. The maximum polymer-silica weight-ratio yielding stable fibres has also been determined. The morphology of the fibres at different weight ratios has been investigated by optical microscopy and scanning electron microscope (SEM). Low aerogel concentrations yield few particles located in polymer...

  2. Controlling solution-phase polymer aggregation with molecular weight and solvent additives to optimize polymer-fullerene bulk heterojunction solar cells

    KAUST Repository

    Bartelt, Jonathan A.; Douglas, Jessica D.; Mateker, William R.; El Labban, Abdulrahman; Tassone, Christopher J.; Toney, Michael F.; Fré chet, Jean Mj J; Beaujuge, Pierre; McGehee, Michael D.

    2014-01-01

    The bulk heterojunction (BHJ) solar cell performance of many polymers depends on the polymer molecular weight (M n) and the solvent additive(s) used for solution processing. However, the mechanism that causes these dependencies is not well

  3. Boiling characteristics of dilute polymer solutions and implications for the suppression of vapor explosions

    Energy Technology Data Exchange (ETDEWEB)

    Bang, K.H.; Kim, M.H. [Univ. of Science and Technology, Pohang (Korea, Republic of)

    1995-09-01

    Quenching experiments of hot solid spheres in dilute aqueous solutions of polyethylene oxide polymer have been conducted for the purpose of investigating the physical mechanisms of the suppression of vapor explosions in this polymer solutions. Two spheres of 22.2mm and 9.5mm-diameter were tested in the polymer solutions of various concentrations at 30{degrees}C. Minimum film boiling temperature ({Delta}T{sub MFB}) in this highly-subcooled liquid rapidly decreased from over 700{degrees}c for pure water to about 150{degrees}C as the polymer concentration was increased up to 300ppm for 22.2mm sphere, and it decreased to 350{degrees}C for 9.5mm sphere. This rapid reduction of minimum film boiling temperature in the PEO aqueous solutions can explain its ability of the suppression of spontaneous vapor explosions. The ability of suppression of vapor explosions by dilute polyethylene oxide solutions against an external trigger pressure was tested by dropping molten tin into the polymer solutions at 25{degrees}C. It was observed that in 50ppm solutions more mass fragmented than in pure water, but produced weaker explosion pressures. The explosion was completely suppressed in 300ppm solutions with the external trigger. The debris size distributions of fine fragments smaller than 0.7mm were shown almost identical regardless of the polymer concentrations.

  4. Universal aspects of macromolecules in polymer blends, solutions, and supercritical mixtures

    International Nuclear Information System (INIS)

    Melnichenko, Y.B.; Wignall, G.D.; Schwahn, D.

    2002-01-01

    We demonstrate that macromolecules in miscible polymer blends may behave as good, Θ, and poor polymeric solvents for each other. We construct a conceptual phase diagram, delineating the range of validity of the random-phase approximation, outside of which polymers contract or expand beyond their unperturbed dimensions, contrary to common assumptions. Remarkably, the correlation length for polymer blends, solutions, and supercritical mixtures collapses onto a master curve, reflecting universal behavior for macromolecules in polymeric and small-molecule Θ solvents

  5. Simple solution-processed titanium oxide electron transport layer for efficient inverted polymer solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Liang [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Shen, Wenfei [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Institute of Hybrid Materials, Laboratory of New Fiber Materials and Modern Textile—The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Chen, Weichao [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Bao, Xichang, E-mail: baoxc@qibebt.ac.cn [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Wang, Ning; Dou, Xiaowei; Han, Liangliang; Wen, Shuguang [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China)

    2014-12-31

    Titanium oxide (TiO{sub X}) is an effective electron transport layer (ETL) in polymer solar cells (PSCs). We report efficient inverted PSCs with a simple solution-processed amorphous TiO{sub X} (s-TiO{sub X}) film as an ETL. The s-TiO{sub X} film with high light transmittance was prepared by spin-coating titanium (IV) isopropoxide isopropanol solution on indium tin oxide coated glass in inert and then placed in air under room temperature for 60 min. The introduction of s-TiO{sub X} ETL greatly improved the short circuit current density of the devices. PSCs based on poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester and poly(4,8-bis-alkyloxy-benzo[1,2-b:4,5-b′]dithiophene-alt-alkylcarbonyl -thieno[3,4-b]thiophene):[6,6]-phenyl- C71-butyric acid methyl ester using s-TiO{sub X} film as ETL shows high power conversion efficiency of 4.29% and 6.7% under the illumination of AM 1.5G, 100 mW/cm{sup 2}, which shows enhancements compared to the conventional PSCs with poly(styrenesulfonate)-doped poly(ethylenedioxythiophene) as anode buffer layer. In addition, the device exhibits good stability in a humid ambient atmosphere without capsulation. The results indicate that the annealing-free, simple solution processed s-TiO{sub X} film is an efficient ETL for high-performance PSCs. - Highlights: • High quality s-TiO{sub X} films were prepared by a simple, solution method without thermal treatment. • The s-TiO{sub X} films with high transmittance are very smooth. • The organic photovoltaic performance with s-TiO{sub X} film improved greatly and exhibited good stability. • The annealing-free, simple prepared s-TiO{sub X} film will be much compatible with flexible substrates.

  6. High performance solution-deposited amorphous indium gallium zinc oxide thin film transistors by oxygen plasma treatment

    KAUST Repository

    Nayak, Pradipta K.

    2012-05-16

    Solution-deposited amorphous indium gallium zinc oxide (a-IGZO) thin film transistors(TFTs) with high performance were fabricated using O2-plasma treatment of the films prior to high temperature annealing. The O2-plasma treatment resulted in a decrease in oxygen vacancy and residual hydrocarbon concentration in the a-IGZO films, as well as an improvement in the dielectric/channel interfacial roughness. As a result, the TFTs with O2-plasma treated a-IGZO channel layers showed three times higher linear field-effect mobility compared to the untreated a-IGZO over a range of processing temperatures. The O2-plasma treatment effectively reduces the required processing temperature of solution-deposited a-IGZO films to achieve the required performance.

  7. Sorption of Ochratoxin A from aqueous solutions using beta-cyclodextrin-polyurethane polymer

    Science.gov (United States)

    The ability of a cyclodextrin-polyurethane polymer to remove ochratoxin A from aqueous solutions, including wine, was examined by batch rebinding assays and equilibrium sorption isotherms. The results were fit to two parameter models. Freundlich analysis of the sorption isotherm indicates the polyme...

  8. Generalized Langevin Theory Of The Brownian Motion And The Dynamics Of Polymers In Solution

    International Nuclear Information System (INIS)

    Tothova, J.; Lisy, V.

    2015-01-01

    The review deals with a generalization of the Rouse and Zimm bead-spring models of the dynamics of flexible polymers in dilute solutions. As distinct from these popular theories, the memory in the polymer motion is taken into account. The memory naturally arises as a consequence of the fluid and bead inertia within the linearized Navier-Stokes hydrodynamics. We begin with a generalization of the classical theory of the Brownian motion, which forms the basis of any theory of the polymer dynamics. The random force driving the Brownian particles is not the white one as in the Langevin theory, but “colored”, i.e., statistically correlated in time, and the friction force on the particles depends on the history of their motion. An efficient method of solving the resulting generalized Langevin equations is presented and applied to the solution of the equations of motion of polymer beads. The memory effects lead to several peculiarities in the time correlation functions used to describe the dynamics of polymer chains. So, the mean square displacement of the polymer coils contains algebraic long-time tails and at short times it is ballistic. It is shown how these features reveal in the experimentally observable quantities, such as the dynamic structure factors of the scattering or the viscosity of polymer solutions. A phenomenological theory is also presented that describes the dependence of these quantities on the polymer concentration in solution. (author)

  9. Polymers for enhanced oil recovery : A paradigm for structure-property relationship in aqueous solution

    NARCIS (Netherlands)

    Wever, D. A. Z.; Picchioni, F.; Broekhuis, A. A.

    Recent developments in the field of water-soluble polymers aimed at enhancing the aqueous solution viscosity are reviewed. Classic and novel associating water-soluble polymers for enhanced oil recovery (EOR) applications are discussed along with their limitations. Particular emphasis is placed on

  10. Micromechanics of Amorphous Metal/Polymer Hybrid Structures with 3D Cellular Architectures: Size Effects, Buckling Behavior, and Energy Absorption Capability.

    Science.gov (United States)

    Mieszala, Maxime; Hasegawa, Madoka; Guillonneau, Gaylord; Bauer, Jens; Raghavan, Rejin; Frantz, Cédric; Kraft, Oliver; Mischler, Stefano; Michler, Johann; Philippe, Laetitia

    2017-02-01

    By designing advantageous cellular geometries and combining the material size effects at the nanometer scale, lightweight hybrid microarchitectured materials with tailored structural properties are achieved. Prior studies reported the mechanical properties of high strength cellular ceramic composites, obtained by atomic layer deposition. However, few studies have examined the properties of similar structures with metal coatings. To determine the mechanical performance of polymer cellular structures reinforced with a metal coating, 3D laser lithography and electroless deposition of an amorphous layer of nickel-boron (NiB) is used for the first time to produce metal/polymer hybrid structures. In this work, the mechanical response of microarchitectured structures is investigated with an emphasis on the effects of the architecture and the amorphous NiB thickness on their deformation mechanisms and energy absorption capability. Microcompression experiments show an enhancement of the mechanical properties with the NiB thickness, suggesting that the deformation mechanism and the buckling behavior are controlled by the brittle-to-ductile transition in the NiB layer. In addition, the energy absorption properties demonstrate the possibility of tuning the energy absorption efficiency with adequate designs. These findings suggest that microarchitectured metal/polymer hybrid structures are effective in producing materials with unique property combinations. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Lattice cluster theory of associating polymers. I. Solutions of linear telechelic polymer chains.

    Science.gov (United States)

    Dudowicz, Jacek; Freed, Karl F

    2012-02-14

    The lattice cluster theory (LCT) for the thermodynamics of a wide array of polymer systems has been developed by using an analogy to Mayer's virial expansions for non-ideal gases. However, the high-temperature expansion inherent to the LCT has heretofore precluded its application to systems exhibiting strong, specific "sticky" interactions. The present paper describes a reformulation of the LCT necessary to treat systems with both weak and strong, "sticky" interactions. This initial study concerns solutions of linear telechelic chains (with stickers at the chain ends) as the self-assembling system. The main idea behind this extension of the LCT lies in the extraction of terms associated with the strong interactions from the cluster expansion. The generalized LCT for sticky systems reduces to the quasi-chemical theory of hydrogen bonding of Panyioutou and Sanchez when correlation corrections are neglected in the LCT. A diagrammatic representation is employed to facilitate the evaluation of the corrections to the zeroth-order approximation from short range correlations. © 2012 American Institute of Physics

  12. Suppressive effects of a polymer sodium silicate solution on ...

    African Journals Online (AJOL)

    Mohsen

    2015-10-21

    Oct 21, 2015 ... suppressive effects of sodium silicate in the polymer form were confirmed against powdery mildew and ... crops (such as rice) controls diseases and could reduce ... negative charge and sodium ions with a positive charge.

  13. Effect of gamma irradiation on viscosity of aqueous solutions of some natural polymers

    International Nuclear Information System (INIS)

    Nguyen Tan Man; Truong Thi Hanh; Le Quang Luan; Le Hai; Nguyen Quoc Hien

    2000-01-01

    Effect of gamma irradiation on viscosity of aqueous solution of alginate and carbon xylmethyl cellulose (CMC) irradiated in solid state has been carried out. the viscosity of aqueous solution of alginate and CMC decreased remarkably with increasing dose and the viscosity of 2% solution of above polymers irradiated at 50 kGy was about 100 times lower than the original one. (author)

  14. A NOVEL INTERPRETATION OF CONCENTRATION DEPENDENCE OF VISCOSITY OF DILUTE POLYMER SOLUTION

    Institute of Scientific and Technical Information of China (English)

    Yan Pan; Rong-shi Cheng

    2000-01-01

    The concentration dependence of the reduced viscosity of dilute polymer solution is interpreted in the light of a new concept of the self-association of polymer chains in dilute solution. The apparent self-association constant is defined as the molar association constant divided by the molar mass of individual polymer chain and is numerically interconvertible with the Huggins coefficient. The molar association constant is directly proportional to the effective hydrodynamic volume of the polymer chain in solution and is irrespective of the chain architecture. The effective hydrodynamic volume accounts for the non-spherical conformation of a short polymer chain in solution and is a product of a shape factor and hydrodynamic volume. The observed enhancement of Huggins coefficient for short chain and branched polymer is satisfactorily interpreted by the concept of self-association. The concept of self-association allows us to predict the existence of a boundary concentration Cs (dynamic contact concentration) which divides the dilute polymer solution into two regions.

  15. Phases of polymer systems in solution studied via molecular dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Joshua Allen [Iowa State Univ., Ames, IA (United States)

    2009-05-01

    Polymers are amazingly versatile molecules with a tremendous range of applications. Our lives would be very different without them. There would be no multitudes of plastic encased electronic gizmos, no latex paint on the walls and no rubber tires, just to name a few of the many commonplace polymer materials. In fact, life as we know it wouldn’t exist without polymers as two of the most essential types of molecules central to cellular life, Proteins and DNA, are both polymers! [1] With their wide range of application to a variety of uses, polymers are still a very active field in basic research. Of particular current interest is the idea of combining polymers with inorganic particles to form novel composite materials. [2] As computers are becoming faster, they are becoming all the more powerful tools for modeling and simulating real systems. With recent advances in computing on graphics processing units (GPUs) [3–7], questions can now be answered via simulation that could not even be asked before. This thesis focuses on the use of computer simulations to model novel polymerinorganic composite systems in order to predict what possible phases can form and under what conditions. The goal is to provide some direction for future experiments and to gain a deeper understanding of the fundamental physics involved. Along the way, there are some interesting and essential side-tracks in the areas of equilibrating complicated phases and accelerating the available computer power with GPU computing, both of which are necessary steps to enable the study of polymer nanocomposites.

  16. Influence of PVP molecular weight on the microwave assisted in situ amorphization of indomethacin

    DEFF Research Database (Denmark)

    Doreth, Maria; Löbmann, Korbinian; Priemel, Petra

    2018-01-01

    . After plasticization by moisture, PVP K12 reached a Tg below ambient temperature (16 ± 2 °C) indicating that the Tg of the plasticized polymer is a key factor for the success of in situ amorphization. DSC analysis showed that the amorphized drug was part of a ternary glass solution consisting of IND......, PVP K12 and water. In dissolution tests, IND:PVP K12 compacts showed a delayed initial drug release due to a lack of compact disintegration, but reached a higher total drug release eventually. In summary, this study showed that the microwave assisted in situ amorphization was highly dependent...... on the Tg of the plasticized polymer....

  17. Modification of a Turbulent Boundary Layer within a Homogeneous Concentration of Drag reducing Polymer Solution

    Science.gov (United States)

    Farsiani, Yasaman; Elbing, Brian

    2017-11-01

    High molecular weight polymer solutions in wall-bounded flows can reduce the local skin friction by as much as 80%. External flow studies have typical focused on injection of polymer within a developing turbulent boundary layer (TBL), allowing the concentration and drag reduction level to evolve with downstream distance. Modification of the log-law region of the TBL is directly related to drag reduction, but recent results suggest that the exact behavior is dependent on flow and polymer properties. Weissenberg number and the viscosity ratio (ratio of solvent viscosity to the zero-shear viscosity) are concentration dependent, thus the current study uses a polymer ocean (i.e. a homogenous concentration of polymer solution) with a developing TBL to eliminate uncertainty related to polymer properties. The near-wall modified TBL velocity profiles are acquired with particle image velocimetry. In the current presentation the mean velocity profiles and the corresponding flow (Reynolds number) and polymer (Weissenberg number, viscosity ratio, and length ratio) properties are reported. Note that the impact of polymer degradation on molecular weight will also be quantified and accounted for when estimating polymer properties This work was supported by NSF Grant 1604978.

  18. Amorphous and nanocrystalline titanium nitride and carbonitride materials obtained by solution phase ammonolysis of Ti(NMe2)4

    International Nuclear Information System (INIS)

    Jackson, Andrew W.; Shebanova, Olga; Hector, Andrew L.; McMillan, Paul F.

    2006-01-01

    Solution phase reactions between tetrakisdimethylamidotitanium (Ti(NMe 2 ) 4 ) and ammonia yield precipitates with composition TiC 0.5 N 1.1 H 2.3 . Thermogravimetric analysis (TGA) indicates that decomposition of these precursor materials proceeds in two steps to yield rocksalt-structured TiN or Ti(C,N), depending upon the gas atmosphere. Heating to above 700 deg. C in NH 3 yields nearly stoichiometric TiN. However, heating in N 2 atmosphere leads to isostructural carbonitrides, approximately TiC 0.2 N 0.8 in composition. The particle sizes of these materials range between 4-12 nm. Heating to a temperature that corresponds to the intermediate plateau in the TGA curve (450 deg. C) results in a black powder that is X-ray amorphous and is electrically conducting. The bulk chemical composition of this material is found to be TiC 0.22 N 1.01 H 0.07 , or Ti 3 (C 0.17 N 0.78 H 0.05 ) 3.96 , close to Ti 3 (C,N) 4 . Previous workers have suggested that the intermediate compound was an amorphous form of Ti 3 N 4 . TEM investigation of the material indicates the presence of nanocrystalline regions x (C,N) y crystalline phases

  19. Communication: Polarizable polymer chain under external electric field in a dilute polymer solution.

    Science.gov (United States)

    Budkov, Yu A; Kolesnikov, A L; Kiselev, M G

    2015-11-28

    We study the conformational behavior of polarizable polymer chain under an external homogeneous electric field within the Flory type self-consistent field theory. We consider the influence of electric field on the polymer coil as well as on the polymer globule. We show that when the polymer chain conformation is a coil, application of external electric field leads to its additional swelling. However, when the polymer conformation is a globule, a sufficiently strong field can induce a globule-coil transition. We show that such "field-induced" globule-coil transition at the sufficiently small monomer polarizabilities goes quite smoothly. On the contrary, when the monomer polarizability exceeds a certain threshold value, the globule-coil transition occurs as a dramatic expansion in the regime of first-order phase transition. The developed theoretical model can be applied to predicting polymer globule density change under external electric field in order to provide more efficient processes of polymer functionalization, such as sorption, dyeing, and chemical modification.

  20. Effect of substrate temperature on corrosion performance of nitrogen doped amorphous carbon thin films in NaCl solution

    Energy Technology Data Exchange (ETDEWEB)

    Khun, N.W. [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Liu, E., E-mail: MEJLiu@ntu.edu.s [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2009-07-01

    Nitrogen doped amorphous carbon (a-C:N) thin films were deposited on p-Si substrates by DC magnetron sputtering at varying substrate temperature from room temperature (RT) to 300 {sup o}C. The bonding structure, surface morphology and adhesion strength of the a-C:N films were investigated by using X-ray photoelectron spectroscopy (XPS), micro-Raman spectroscopy, atomic force microscopy (AFM) and micro-scratch testing. The corrosion behavior of the a-C:N films was evaluated by potentiodynamic polarization test in a 0.6 M NaCl solution. The results indicated that the corrosion resistance of the films depended on the sp{sup 3}-bonded cross-link structure that was significantly affected by the substrate temperature.

  1. Effect of substrate temperature on corrosion performance of nitrogen doped amorphous carbon thin films in NaCl solution

    International Nuclear Information System (INIS)

    Khun, N.W.; Liu, E.

    2009-01-01

    Nitrogen doped amorphous carbon (a-C:N) thin films were deposited on p-Si substrates by DC magnetron sputtering at varying substrate temperature from room temperature (RT) to 300 o C. The bonding structure, surface morphology and adhesion strength of the a-C:N films were investigated by using X-ray photoelectron spectroscopy (XPS), micro-Raman spectroscopy, atomic force microscopy (AFM) and micro-scratch testing. The corrosion behavior of the a-C:N films was evaluated by potentiodynamic polarization test in a 0.6 M NaCl solution. The results indicated that the corrosion resistance of the films depended on the sp 3 -bonded cross-link structure that was significantly affected by the substrate temperature.

  2. The nonaqueous inhibition of Fe-Co-B-Si amorphous electrodes: An a.c. impedance study in HCl solutions

    International Nuclear Information System (INIS)

    Habib, K.; Abdullah, A.

    1995-01-01

    An electrochemical study on Fe-Co-B-Si amorphous electrodes has been conducted. The study was focused on determining the electrochemical impedance spectroscopy (EIS) of four different alloys of Fe-Co-B-Si in various HCl acid solutions. The A.C. impedance and the capacitance of Fe-Co-B-Si, Co-Fe-Ni-B-Si, Co-Fe-Mn-B-Si, and Co-Fe-Ni-Mo-B-Si alloys were obtained in 25, 50, 75 and 100% of HCl acid at room temperature. Electrochemical parameters, i.e., impedance, were found to vary depending on additions of the Ni, Mn, Ni-Mo to Fe-Co-B-Si alloy, the acid concentration, and the nanoscopic surface roughness of the electrodes. Consequently, a correlation between the obtained data is established

  3. Multiresolution Modeling of Semidilute Polymer Solutions: Coarse-Graining Using Wavelet-Accelerated Monte Carlo

    Directory of Open Access Journals (Sweden)

    Animesh Agarwal

    2017-09-01

    Full Text Available We present a hierarchical coarse-graining framework for modeling semidilute polymer solutions, based on the wavelet-accelerated Monte Carlo (WAMC method. This framework forms a hierarchy of resolutions to model polymers at length scales that cannot be reached via atomistic or even standard coarse-grained simulations. Previously, it was applied to simulations examining the structure of individual polymer chains in solution using up to four levels of coarse-graining (Ismail et al., J. Chem. Phys., 2005, 122, 234901 and Ismail et al., J. Chem. Phys., 2005, 122, 234902, recovering the correct scaling behavior in the coarse-grained representation. In the present work, we extend this method to the study of polymer solutions, deriving the bonded and non-bonded potentials between coarse-grained superatoms from the single chain statistics. A universal scaling function is obtained, which does not require recalculation of the potentials as the scale of the system is changed. To model semi-dilute polymer solutions, we assume the intermolecular potential between the coarse-grained beads to be equal to the non-bonded potential, which is a reasonable approximation in the case of semidilute systems. Thus, a minimal input of microscopic data is required for simulating the systems at the mesoscopic scale. We show that coarse-grained polymer solutions can reproduce results obtained from the more detailed atomistic system without a significant loss of accuracy.

  4. Specific Ion Effects in Thermo-Responsive Polymer Solutions

    DEFF Research Database (Denmark)

    Moghaddam, Saeed Zajforoushan

    Stimuli-responsive polymers are macromolecules that undergo a significant change in conformation and interactions in response to an external stimulus such as temperature and addition of salts. The applications of these materials are numerous ranging from biomedical applications to fabrication of ...

  5. Scaling Behavior of Dilute Polymer Solutions Confined between Parallel Plates

    NARCIS (Netherlands)

    Vliet, J.H. van; Luyten, M.C.; Brinke, G. ten

    1992-01-01

    The average size and shape of a polymer coil confined in a slit between two parallel plates depends on the distance L between the plates. On the basis of numerical results, four different regimes can be distingubhed. For large values of L the coil is essentially unconfined. For intermediate values

  6. On the origin of the Vogel–Fulcher–Tammann law in the thermo-responsive shape memory effect of amorphous polymers

    International Nuclear Information System (INIS)

    Lu, Haibao; Huang, Wei Min

    2013-01-01

    All amorphous shape memory polymers (SMPs) are featured by their relaxation behavior above and below the switching transition temperature (T SW ). Above T SW , the glass transition and secondary transition merge together, resulting in the cooperative (α) movement in polymer macromolecules. Below T SW , movement is non-cooperative (β). In this study, three thermodynamic constitutive frameworks for the shape recovery behavior in amorphous SMPs are proposed based on the Arrhenius, Vogel–Fulcher–Tammann (VFT) and Bässler laws, respectively, and incorporated with parameters (stress, strain and relaxation time) as functions of temperature. The relaxation times of α and β movements satisfy the VFT and Arrhenius laws, respectively. The simulation is compared with the available experimental results reported in the literature for verification. The VFT law is found to be better than the other models, and is able to provide an accurate prediction for the temperature dependent relaxation behavior, from the Arrhenius behavior below, to the Williams–Landel–Ferry behavior above T SW . (paper)

  7. CONDENSED MATTER: STRUCTURE, MECHANICAL AND THERMAL PROPERTIES: Molecular Dynamics Study of Stability of Solid Solutions and Amorphous Phase in the Cu-Al System

    Science.gov (United States)

    Yang, Bin; Lai, Wen-Sheng

    2009-06-01

    The relative stability of fcc and bcc solid solutions and amorphous phase with different compositions in the Cu-Al system is studied by molecular dynamics simulations with n-body potentials. For Cu1-xAlx alloys, the calculations show that the fcc solid solution has the lowest energies in the composition region with x 0.72, while the bee solid solution has the lowest energies in the central composition range, in agreement with the ball-milling experiments that a single bcc solid solution with 0.30 < x < 0.70 is obtained. The evolution of structures in solid solutions and amorphous phase is studied by the coordination number (CN) and bond-length analysis so as to unveil the underlying physics. It is found that the energy sequence among three phases is determined by the competition in energy change originating from the bond length and CNs (or the number of bonds).

  8. Improvement of Physico-mechanical Properties of Partially Amorphous Acetaminophen Developed from Hydroalcoholic Solution Using Spray Drying Technique

    Science.gov (United States)

    Sadeghi, Fatemeh; Torab, Mansour; Khattab, Mostafa; Homayouni, Alireza; Afrasiabi Garekani, Hadi

    2013-01-01

    Objective(s): This study was performed aiming to investigate the effect of particle engineering via spray drying of hydroalcoholic solution on solid states and physico-mechanical properties of acetaminophen. Materials and Methods: Spray drying of hydroalcoholic solution (25% v/v ethanol/water) of acetaminophen (5% w/v) in the presence of small amounts of polyninylpyrrolidone K30 (PVP) (0, 1.25, 2.5 and 5% w/w based on acetaminophen weight) was carried out. The properties of spray dried particles namely morphology, surface characteristics, particle size, crystallinity, dissolution rate and compactibility were evaluated. Results: Spray drying process significantly changed the morphology of acetaminophen crystals from acicular (rod shape) to spherical microparticle. Differential scanning calorimetery (DSC) and x-ray powder diffraction (XRPD) studies ruled out any polymorphism in spray dried samples, however, a major reduction in crystallinity up to 65%, especially for those containing 5% w/w PVP was observed. Spray dried acetaminophen particles especially those obtained in the presence of PVP exhibited an obvious improvement of the dissolution and compaction properties. Tablets produced from spray dried samples exhibited excellent crushing strengths and no tendency to cap. Conclusions: The findings of this study revealed that spray drying of acetaminophen from hydroalcoholic solution in the presence of small amount of PVP produced partially amorphous particles with improved dissolution and excellent compaction properties. PMID:24379968

  9. Investigation of the in-solution relaxation of polymer optical fibre Bragg gratings

    DEFF Research Database (Denmark)

    Fasano, Andrea; Woyessa, Getinet; Janting, Jakob

    2016-01-01

    We investigate the response of PMMA microstructured polymer optical fibre Bragg gratings whenimmersed in methanol/water solutions. Overall we observe a permanent blue-shift in Bragg gratingwavelength after solvent evaporation. The main contribution in the resonance wavelength shift probably...... arisesfrom a permanent change in the size of the fibre, as already reported for high-temperature annealing ofpolymer optical fibres. As a consequence of the solution concentration dependence of the glass transitiontemperature of polymers, different methanol/water solutions lead to various degrees of frozen...

  10. Comparison of nanoparticle diffusion using fluorescence correlation spectroscopy and differential dynamic microscopy within concentrated polymer solutions

    Science.gov (United States)

    Shokeen, Namita; Issa, Christopher; Mukhopadhyay, Ashis

    2017-12-01

    We studied the diffusion of nanoparticles (NPs) within aqueous entangled solutions of polyethylene oxide (PEO) by using two different optical techniques. Fluorescence correlation spectroscopy, a method widely used to investigate nanoparticle dynamics in polymer solution, was used to measure the long-time diffusion coefficient (D) of 25 nm radius particles within high molecular weight, Mw = 600 kg/mol PEO in water solutions. Differential dynamic microscopy (DDM) was used to determine the wave-vector dependent dynamics of NPs within the same polymer solutions. Our results showed good agreement between the two methods, including demonstration of normal diffusion and almost identical diffusion coefficients obtained by both techniques. The research extends the scope of DDM to study the dynamics and rheological properties of soft matter at a nanoscale. The measured diffusion coefficients followed a scaling theory, which can be explained by the coupling between polymer dynamics and NP motion.

  11. SANS structural characterization of fullerenol-derived star polymers in solutions

    CERN Document Server

    Jeng, U S; Wang, L Y; Chiang, L Y; Ho, D L; Han, C C

    2002-01-01

    We have studied the chain conformations of fullerenol-derived star polymers in two organic solvents using small-angle neutron scattering (SANS). The SANS results indicate that the six poly(urethane-ether) arms, chemically bonded on the fullerenol of the C sub 6 sub 0 -based star polymer, have a Gaussian chain conformation in toluene. However, these arms exhibit a pronounced excluded-volume effect in dimethylformamide solutions. We use a scattering model, with the polydispersity of the polymer taken into account, and a fractal model to extract the radius of gyration R sub g values and the persistence lengths of the C sub 6 sub 0 -star polymers in these two organic solutions. (orig.)

  12. Manufacturing polymer light emitting diode with high luminance efficiency by solution process

    Science.gov (United States)

    Kim, Miyoung; Jo, SongJin; Yang, Ho Chang; Yoon, Dang Mo; Kwon, Jae-Taek; Lee, Seung-Hyun; Choi, Ju Hwan; Lee, Bum-Joo; Shin, Jin-Koog

    2012-06-01

    While investigating polymer light emitting diodes (polymer-LEDs) fabricated by solution process, surface roughness influences electro-optical (E-O) characteristics. We expect that E-O characteristics such as luminance and power efficiency related to surface roughness and layer thickness of emitting layer with poly-9-Vinylcarbazole. In this study, we fabricated polymer organic light emitting diodes by solution process which guarantees easy, eco-friendly and low cost manufacturing for flexible display applications. In order to obtain high luminescence efficiency, E-O characteristics of these devices by varying parameters for printing process have been investigated. Therefore, we optimized process condition for polymer-LEDs by adjusting annealing temperatures of emission, thickness of emission layer showing efficiency (10.8 cd/A) at 10 mA/cm2. We also checked wavelength dependent electroluminescence spectrum in order to find the correlation between the variation of efficiency and the thickness of the layer.

  13. Visualizing phase transition behavior of dilute stimuli responsive polymer solutions via Mueller matrix polarimetry.

    Science.gov (United States)

    Narayanan, Amal; Chandel, Shubham; Ghosh, Nirmalya; De, Priyadarsi

    2015-09-15

    Probing volume phase transition behavior of superdiluted polymer solutions both micro- and macroscopically still persists as an outstanding challenge. In this regard, we have explored 4 × 4 spectral Mueller matrix measurement and its inverse analysis for excavating the microarchitectural facts about stimuli responsiveness of "smart" polymers. Phase separation behavior of thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) and pH responsive poly(N,N-(dimethylamino)ethyl methacrylate) (PDMAEMA) and their copolymers were analyzed in terms of Mueller matrix derived polarization parameters, namely, depolarization (Δ), diattenuation (d), and linear retardance (δ). The Δ, d, and δ parameters provided useful information on both macro- and microstructural alterations during the phase separation. Additionally, the two step action ((i) breakage of polymer-water hydrogen bonding and (ii) polymer-polymer aggregation) at the molecular microenvironment during the cloud point generation was successfully probed via these parameters. It is demonstrated that, in comparison to the present techniques available for assessing the hydrophobic-hydrophilic switch over of simple stimuli-responsive polymers, Mueller matrix polarimetry offers an important advantage requiring a few hundred times dilute polymer solution (0.01 mg/mL, 1.1-1.4 μM) at a low-volume format.

  14. Making Molecular Balloons in Laser-Induced Explosive Boiling of Polymer Solutions

    International Nuclear Information System (INIS)

    Leveugle, Elodie; Sellinger, Aaron; Fitz-Gerald, James M.; Zhigilei, Leonid V.

    2007-01-01

    The effect of the dynamic molecular rearrangements leading to compositional segregation is revealed in coarse-grained molecular dynamics simulations of short pulse laser interaction with a polymer solution in a volatile matrix. An internal release of matrix vapor at the onset of the explosive boiling of the overheated liquid is capable of pushing polymer molecules to the outskirts of a transient bubble, forming a polymer-rich surface layer enclosing the volatile matrix material. The results explain unexpected 'deflated balloon' structures observed in films deposited by the matrix-assisted pulsed laser evaporation technique

  15. Inert gas annealing effect in solution-processed amorphous indium-gallium-zinc-oxide thin-film transistors

    Science.gov (United States)

    Lee, Seungwoon; Jeong, Jaewook

    2017-08-01

    In this paper, the annealing effect of solution-processed amorphous indium-gallium-zinc-oxide thin-film transistors (a-IGZO TFTs), under ambient He (He-device), is systematically analyzed by comparison with those under ambient O2 (O2-device) and N2 (N2-device), respectively. The He-device shows high field-effect mobility and low subthreshold slope owing to the minimization of the ambient effect. The degradation of the O2- and N2-device performances originate from their respective deep acceptor-like and shallow donor-like characteristics, which can be verified by comparison with the He-device. However, the three devices show similar threshold voltage instability under prolonged positive bias stress due to the effect of excess oxygen. Therefore, annealing in ambient He is the most suitable method for the fabrication of reference TFTs to study the various effects of the ambient during the annealing process in solution-processed a-IGZO TFTs.

  16. Investigation of the required length for fully developed pipe flow with drag-reducing polymer solutions

    Science.gov (United States)

    Farsiani, Yasaman; Elbing, Brian

    2015-11-01

    Adding trace amounts of long chain polymers into a liquid flow is known to reduce skin friction drag by up to 80%. While polymer drag reduction (PDR) has been successfully implemented in internal flows, diffusion and degradation have limited its external flow applications. A weakness in many previous PDR studies is that there was no characterization of the polymer being injected into the turbulent boundary layer, which can be accomplished by testing a sample in a pressure-drop tube. An implicit assumption in polymer characterization is that the flow is fully developed at the differential pressure measurement. While available data in the literature shows that the entry length to achieve fully developed flow increases with polymeric solutions, it is unclear how long is required to achieve fully developed flow for non-Newtonian turbulent flows. In the present study, the pressure-drop is measured across a 1.05 meter length section of a 1.04 cm inner diameter pipe. Differential pressure is measured with a pressure transducer for different entry lengths, flow and polymer solution properties. This presentation will present preliminary data on the required entrance length as well as characterization of polymer solution an estimate of the mean molecular weight.

  17. Drag reduction behavior of hydrolyzed polyacrylamide/xanthan gum mixed polymer solutions

    Institute of Scientific and Technical Information of China (English)

    Mehdi Habibpour; Peter E.Clark

    2017-01-01

    Partially hydrolyzed polyacrylamide (HPAM) as the main component of slickwater fracturing fluid is a shear-sensitive polymer,which suffers from mechanical degradation at turbulent flow rates.Five different concentrations of HPAM as well as mixtures of polyacrylamide/xanthan gum were prepared to investigate the possibility of improving shear stability of HPAM.Drag reduction (DR)measurements were performed in a closed flow loop.For HPAM solutions,the extent of DR increased from 30% to 67% with increasing HPAM concentration from 100 to 1000 wppm.All the HPAM solutions suffered from mechanical degradation and loss of DR efficiency over the shearing period.Results indicated that the resistance to shear degradation increased with increasing polymer concentration.DR efficiency of 600 wppm xanthan gum (XG)was 38%,indicating that XG was not as good a drag reducer as HPAM.But with only 6% DR decline,XG solution exhibited a better shear stability compared to HPAM solutions.Mixed HPAM/XG solutions initially exhibited greater DR (40% and 55%) compared to XG,but due to shear degradation,DR% dropped for HPAM/XG solutions.Compared to 200 wppm HPAM solution,addition of XG did not improve the drag reduction efficiency of HPAM/XG mixed solutions though XG slightly improved the resistance against mechanical degradation in HPAM/XG mixed polymer solutions.

  18. Rheological Properties of Associative Star Polymers in Aqueous Solutions: Effect of Hydrophobe Length and Polymer Topology

    DEFF Research Database (Denmark)

    Hietala, Sami; Strandman, Satu; Jarvi, Paula

    2009-01-01

    triblock copolymer. These polymers, synthesized by atom transfer radical polymerization (ATRP), were found to form hydrogels due to intermolecular association originating from the PS blocks. The increasing length of the PS block was observed to lead to more elastic networks due to increased hydrophobic...

  19. Carbon Nanotube Dispersion in Solvents and Polymer Solutions: Mechanisms, Assembly, and Preferences.

    Science.gov (United States)

    Pramanik, Chandrani; Gissinger, Jacob R; Kumar, Satish; Heinz, Hendrik

    2017-12-26

    Debundling and dispersion of carbon nanotubes (CNTs) in polymer solutions play a major role in the preparation of carbon nanofibers due to early effects on interfacial ordering and mechanical properties. A roadblock toward ultrastrong fibers is the difficulty to achieve homogeneous dispersions of CNTs in polyacrylonitrile (PAN) and poly(methyl methacrylate) (PMMA) precursor solutions in solvents such as dimethyl sulfoxide (DMSO), N,N-dimethylacetamide (DMAc), and N,N-dimethylformamide (DMF). In this contribution, molecular dynamics simulations with accurate interatomic potentials for graphitic materials that include virtual π electrons are reported to analyze the interaction of pristine single wall CNTs with the solvents and polymer solutions at 25 °C. The results explain the barriers toward dispersion of SWCNTs and quantify CNT-solvent, polymer-solvent, as well as CNT-polymer interactions in atomic detail. Debundling of CNTs is overall endothermic and unfavorable with dispersion energies of +20 to +30 mJ/m 2 in the pure solvents, + 20 to +40 mJ/m 2 in PAN solutions, and +20 to +60 mJ/m 2 in PMMA solutions. Differences arise due to molecular geometry, polar, van der Waals, and CH-π interactions. Among the pure solvents, DMF restricts CNT dispersion less due to the planar geometry and stronger van der Waals interactions. PAN and PMMA interact favorably with the pure solvents with dissolution energies of -0.7 to -1.1 kcal per mole monomer and -1.5 to -2.2 kcal per mole monomer, respectively. Adsorption of PMMA onto CNTs is stronger than that of PAN in all solvents as the molecular geometry enables more van der Waals contacts between alkyl groups and the CNT surface. Polar side groups in both polymers prefer interactions with the polar solvents. Higher polymer concentrations in solution lead to polymer aggregation via alkyl groups and reduce adsorption onto CNTs. PAN and PMMA solutions in DMSO and dilute solutions in DMF support CNT dispersion more than other

  20. Sorption of ochratoxin A from aqueous solutions using β-cyclodextrin-polyurethane polymer.

    Science.gov (United States)

    Appell, Michael; Jackson, Michael A

    2012-02-01

    The ability of a cyclodextrin-polyurethane polymer to remove ochratoxin A from aqueous solutions was examined by batch rebinding assays. The results from the aqueous binding studies were fit to two parameter models to gain insight into the interaction of ochratoxin A with the nanosponge material. The ochratoxin A sorption data fit well to the heterogeneous Freundlich isotherm model. The polymer was less effective at binding ochratoxin A in high pH buffer (9.5) under conditions where ochratoxin A exists predominantly in the dianionic state. Batch rebinding assays in red wine indicate the polymer is able to remove significant levels of ochratoxin A from spiked solutions between 1-10 μg·L(-1). These results suggest cyclodextrin nanosponge materials are suitable to reduce levels of ochratoxin A from spiked aqueous solutions and red wine samples.

  1. Assessment of Some Synthetic Polymers for the Removal of Pollutants from Waste Solutions

    International Nuclear Information System (INIS)

    Ayoub, R.; El-Naggar, H.A.; Ezz EL-Din, M.R.; Moussa, A.R.

    1999-01-01

    The sorption capacity of 134 Cs, 60 Co, 152+154 Eu and Cu (II) by three prepared has been studied using batch and column techniques. The three polymers are polyacrylic acid (PAA), polyacrylamide-acrylic acid (PAM-AA) and polyacrylamide-N-vinyl-2-pyrraldone (PAM-NVP). These polymers were prepared by gamma radiation initiated polymerization of their corresponding monomer solutions. The appropriate value for V/m ratio (volume of solution to mass of polymer) that can result in reasonably high distribution coefficient, Kd, was determined. The variation of the amount sorbed of the isotope per gram polymer (X/m) with concentration of the relevant element was found to follow a Frendlich type isotherm. The distribution coefficient, Kd, of the studied element was found to be affected by the ph of the solution. The desorption of the investigated metal ions is also studied at different ph. For column studies, the percent removed of the radioisotopes 134 Cs, 60 Co, ( 152+154 )Eu in addition to some heavy metals ions such as Pb, Cd, Zn and Cu(II) was determined. More than 95% of these elements were removed when 3 beds column of PAA or PAM-AA was used. From the data obtained we can conclude that the polymer PAA or PAM-AA can considered as an efficient sorbent for metal cations from their aqueous solution

  2. Bridging the Gap between Polymer Melts and Solutions in Extensional Rheology

    DEFF Research Database (Denmark)

    Huang, Qian; Hengeller, Ludovica; Alvarez, Nicolas J.

    2015-01-01

    Since its inception, the tube model of polymer dynamics has undergone several modifications to account for observed experimental trends. One trend that has yet to be captured by a modified version of the tube model is the observed experimental difference between concentrated polymer solutions...... per chain and are diluted in the same solvent (oligomeric styrene). We show that the difference in nonlinear rheological behavior between polystyrene melts reported by Bach et al.1 and polystyrene solutions reported by Bhattacharjee et al.2 and Sridhar et al.3 can be bridged by changing...... the polystyrene concentration. The results presented represent a unique benchmark for all future modifications to the tube model....

  3. CISM Course on Fluid Mechanics of Surfactant and Polymer Solutions

    CERN Document Server

    Ivanov, Ivan

    2004-01-01

    Colloidal systems and dispersions are of great importance in oil recovery, waist water treatment, coating, food and beverage industry, pharmaceutical industry, medicine, environmental protection etc. Colloidal systems and dispersions are always multi-component and multiphase systems. In these systems at least one dimension is in a range of colloidal forces action: colloidal dispersions/emulsions are examples of three dimensional colloidal systems, while thin liquid films are examples of one dimensional colloidal systems. The contribution presented in this issue deals with flow, distribution and redistribution, coating and deposition of surfactant and polymer molecules in colloidal systems. The book presents reviews of recent advances and trends by well-know scientists and engineers in this area.

  4. Spectroscopic and calorimetric investigation of short and intermediate-range structures and energetics of amorphous SiCO, SiCN, and SiBCN polymer-derived ceramics

    Science.gov (United States)

    Widgeon, Scarlett J.

    Polymer-derived ceramics (PDCs) are a new class of amorphous ceramics in the Si-B-C-N system that are synthesized by the pyrolysis of silicon-based organic polymers. PDCs are lightweight and are resistant to creep, crystallization, and oxidation at temperatures near 1800 K making them ideal for a variety of high temperature applications. In spite of being X-ray amorphous, these materials display structural heterogeneity at the nanometer length scale. Their structure and resulting properties can be drastically altered by the utilization of preceramic polymers with differing chemistry and architectures. Fundamental understanding of the atomic structure is critical in deciphering the structure-property relationships and ultimately in controlling their properties for specific engineering applications. The short-range atomic structure has been extensively investigated using a variety of techniques, however, the structures at length scales beyond next-nearest neighbors remained highly controversial. Here we report the results of a spectroscopic and calorimetric study of short and intermediate -range structure and energetic of SiOC and SiBCN PDCs derived from a wide variety of precursors. SiOC PDCs with different carbon contents were synthesized from polysiloxane precurors and their structures were studied using high-resolution 13C and 29Si nuclear magnetic resonance (NMR) spectroscopy. The results suggest that these PDCs consists of a continuous mass fractal backbone of corner-shared SiC xO4-x tetrahedral units with "voids" occupied by sp 2-hybridized graphitic carbon. The oxygen-rich SiCxO 4-x units are located at the interior of this backbone with a mass fractal dimension of ~ 2.5, while the carbon-rich units occupy the two-dimensional interface between the backbone and the free carbon nanodomains. Such fractal topology is expected to give rise to unusual mechanical and transport properties characteristic of fractal percolation networks. For example, elastic moduli and

  5. Monomers and polymers in a centrifugal field : a new method to produce refractive-index gradients in polymers

    NARCIS (Netherlands)

    Duijnhoven, van F.G.H.; Bastiaansen, C.W.M.

    1999-01-01

    A new method is presented to generate and to fixate compositional gradients in blends of two miscible and amorphous polymers. A compositional gradient is introduced into a solution of a polymer in a monomer by use of a centrifugal field, and this gradient is subsequently fixated by polymerization of

  6. Photoinduced partial charge transfer between conjugated polymer and fullerene in solutions

    International Nuclear Information System (INIS)

    Lin Hongzhen; Weng Yufeng; Huang Hongmin; He Qingguo; Zheng Min; Bai Fenglian

    2004-01-01

    Photoinduced charge transfer between a conjugated polymer and C 60 and the related processes were investigated in dilute solutions. The substantial fluorescence quenching is correlated with the efficient exciton diffusion within the polymer chains, according to which a sphere-of-action mechanism is proposed. An emissive exciplex was found formed between the conjugated polymer and fullerene in a nonpolar solvent, indicating the occurrence of a photoinduced partial charge transfer process. The low-energy sites in the polymer are believed to play a crucial role in the partial charge transfer. The asymmetry of the exciplex provides a method for evaluating the tendency of photoinduced charge separation between the donor and the acceptor. This method allows screening candidates for photovoltaic applications

  7. Impact of soft annealing on the performance of solution-processed amorphous zinc tin oxide thin-film transistors

    KAUST Repository

    Nayak, Pradipta K.

    2013-05-08

    It is demonstrated that soft annealing duration strongly affects the performance of solution-processed amorphous zinc tin oxide thin-film transistors. Prolonged soft annealing times are found to induce two important changes in the device: (i) a decrease in zinc tin oxide film thickness, and (ii) an increase in oxygen vacancy concentration. The devices prepared without soft annealing exhibited inferior transistor performances, in comparison to devices in which the active channel layer (zinc tin oxide) was subjected to soft annealing. The highest saturation field-effect mobility - 5.6 cm2 V-1 s-1 with a drain-to-source on-off current ratio (Ion/Ioff) of 2 × 108 - was achieved in the case of devices with 10-min soft-annealed zinc tin oxide thin films as the channel layer. The findings of this work identify soft annealing as a critical parameter for the processing of chemically derived thin-film transistors, and it correlates device performance to the changes in material structure induced by soft annealing. © 2013 American Chemical Society.

  8. Free Surface Flows and Extensional Rheology of Polymer Solutions

    Science.gov (United States)

    Dinic, Jelena; Jimenez, Leidy Nallely; Biagioli, Madeleine; Estrada, Alexandro; Sharma, Vivek

    Free-surface flows - jetting, spraying, atomization during fuel injection, roller-coating, gravure printing, several microfluidic drop/particle formation techniques, and screen-printing - all involve the formation of axisymmetric fluid elements that spontaneously break into droplets by a surface-tension-driven instability. The growth of the capillary-driven instability and pinch-off dynamics are dictated by a complex interplay of inertial, viscous and capillary stresses for simple fluids. Additional contributions by elasticity, extensibility and extensional viscosity play a role for complex fluids. We show that visualization and analysis of capillary-driven thinning and pinch-off dynamics of the columnar neck in an asymmetric liquid bridge created by dripping-onto-substrate (DoS) can be used for characterizing the extensional rheology of complex fluids. Using a wide variety of complex fluids, we show the measurement of the extensional relaxation time, extensional viscosity, power-law index and shear viscosity. Lastly, we elucidate how polymer composition, flexibility, and molecular weight determine the thinning and pinch-off dynamics of polymeric complex fluids.

  9. Synthesis and Rheological Properties of an Associative Star Polymer in Aqueous Solutions

    DEFF Research Database (Denmark)

    Hietala, Sami; Mononen, Pekka; Strandman, Satu

    2007-01-01

    synthesised by atom transfer radical. polymerization (ATRP) was found to fonn hydrogels at room temperature at polymer concentrations. Cp, over 22 gIL due to the interpolymer drophobic association of the PS blocks. Increasing Cp leads to stronger elastic networks at room temperature that show a gel......Rheological properties of aqueous solutions and hydrogels fonned by an amphiphiIic star block copolymer poly(acrylic acid)-blockpolystyrene (PAAS4-b-PS6)4. were investigated as a function of the polymer concentration (Cp), temperature, and added saIt concentration. The water-soluble polymer......-to-solution transition with increasing temperature. Increase of ionic strength decreases the moduli compared with the pure hydrogel but did not affect the gel-sol transition temperature significantly. Small-angle X-ray experiments showed two distinct scattering correlation peaks for samples above the gelling Cp, which...

  10. Degradation of homogeneous polymer solutions in high shear turbulent pipe flow

    Science.gov (United States)

    Elbing, B. R.; Winkel, E. S.; Solomon, M. J.; Ceccio, S. L.

    2009-12-01

    This study quantifies degradation of polyethylene oxide (PEO) and polyacrylamide (PAM) polymer solutions in large diameter (2.72 cm) turbulent pipe flow at Reynolds numbers to 3 × 105 and shear rates greater than 105 1/s. The present results support a universal scaling law for polymer chain scission reported by Vanapalli et al. (2006) that predicts the maximum chain drag force to be proportional to Re 3/2, validating this scaling law at higher Reynolds numbers than prior studies. Use of this scaling gives estimated backbone bond strengths from PEO and PAM of 3.2 and 3.8 nN, respectively. Additionally, with the use of synthetic seawater as a solvent the onset of drag reduction occurred at higher shear rates relative to the pure water solvent solutions, but had little influence on the extent of degradation at higher shear rates. These results are significant for large diameter pipe flow applications that use polymers to reduce drag.

  11. Cementation of the solid radioactive waste with polymer-cement solutions using the method of impregnation

    International Nuclear Information System (INIS)

    Gorbunova, O.

    2015-01-01

    Cementation of solid radioactive waste (SRW), i.e. inclusion of solid radioactive waste into cement matrix without cavities - is one of the main technological processes used for conditioning low and intermediate level radioactive waste. At FSUE 'Radon' the industrialized method of impregnation has been developed and since 2003 has been using for cementation of solid radioactive waste. The technology is that the polymer-cement solution, having high penetrating properties, is supplied under pressure through a tube to the bottom of the container in which solid radioactive waste has preliminarily been placed. The polymer-cement solution is evenly moving upwards through the channels between the particles of solid radioactive waste, fills the voids in the bulk volume of the waste and hardens, forming a cement compound, the amount of which is equal to the original volume. The aim of the investigation was a selection of a cement solution suitable for SRW impregnation (including fine particles) without solution depletion and bottom layers stuffing. It has been chosen a polymer: PHMG (polyhexamethylene-guanidine), which is a stabilizing and water-retaining component of the cement solution. The experiments confirm that the polymer increases the permeability of the cement solution by a 2-2.5 factor, the viscosity by a 1.2 factor, the stability of the consistency by a 1.5-1.7 factor, and extends the operating range of the W/C ratio to 0.5-1.1. So it is possible to penetrate a volume of SRW bigger by a 1.5-2.0 factor. It has been proved, that PHMG polymer increases strength and frost-resistance of the final compounds by a 1.8-2.7 factor, and contributes to fast strength development at the beginning of hardening and it decreases Cs-137 leashing rate by a 1.5-2 factor

  12. Preferential adsorption of uranium ions in aqueous solutions by polymers

    International Nuclear Information System (INIS)

    Sakuragi, Masako; Ichimura, Kunihiro; Fujishige, Shoei; Kato, Masao

    1981-01-01

    Amidoxime fiber and triazine fiber were prepared by chemical modification of commercially available polyacrylonitril fiber. It was found that the Amidoxime fiber is efficient to adsorb uranium ions in the artificial sea water. The efficiency of the preferential adsorption decreases by treatment the material with an acid-or an alkaline-solution. The triazine fiber adsorbs uranium ions only in aqueous solutions of such uranyl acetate, in the absence of other ions. In the artificial sea water, it adsorbs other ions instead of uranium. The preferential adsorption of uranium ions was further investigated with a series of polystyrenesulfonamides. Among the polystyrene derivatives, those having carboxyl groups, derived from imino diacetic acid (PSt-Imi), β-alanine (PSt-Ala), glycine (PSt-Gly), and sarcosine (PSt-Sar) were qualified for further discussion. However, it was found that the amount of adsorption of uranium ions by PSt-Imi decreases with increasing the volume of the artificial sea water and/or the duration of the treatment. Taking into account the facts, the preferential adsorption of uranium ions by PSt-Imi in aqueous solution was discussed in detail. (author)

  13. Hydrodynamics of isotropic and liquid crystalline active polymer solutions.

    Science.gov (United States)

    Ahmadi, Aphrodite; Marchetti, M C; Liverpool, T B

    2006-12-01

    We describe the large-scale collective behavior of solutions of polar biofilaments and stationary and mobile crosslinkers. Both mobile and stationary crosslinkers induce filament alignment promoting either polar or nematic order. In addition, mobile crosslinkers, such as clusters of motor proteins, exchange forces and torques among the filaments and render the homogeneous states unstable via filament bundling. We start from a Smoluchowski equation for rigid filaments in solutions, where pairwise crosslink-mediated interactions among the filaments yield translational and rotational currents. The large-scale properties of the system are described in terms of continuum equations for filament and motor densities, polarization, and alignment tensor obtained by coarse-graining the Smoluchovski equation. The possible homogeneous and inhomogeneous states of the systems are obtained as stable solutions of the dynamical equations and are characterized in terms of experimentally accessible parameters. We make contact with work by other authors and show that our model allows for an estimate of the various parameters in the hydrodynamic equations in terms of physical properties of the crosslinkers.

  14. Thermally Activated Delayed Fluorescence in Polymers: A New Route toward Highly Efficient Solution Processable OLEDs.

    Science.gov (United States)

    Nikolaenko, Andrey E; Cass, Michael; Bourcet, Florence; Mohamad, David; Roberts, Matthew

    2015-11-25

    Efficient intermonomer thermally activated delayed fluorescence is demonstrated for the first time, opening a new route to achieving high-efficiency solution processable polymer light-emitting device materials. External quantum efficiency (EQE) of up to 10% is achieved in a simple fully solution-processed device structure, and routes for further EQE improvement identified. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. On the dynamics of polymer mixtures in solution using the RPA

    International Nuclear Information System (INIS)

    Benmouna, M.

    1989-09-01

    The dynamics of polymer mixtures and copolymers in solution is investigated using the Random Phase Approximation (RPA). It is shown that the known results for the intermediate scattering functions are recovered in the Rouse limit only. If hydrodynamic interaction is not negligible, a discrepancy appears. This discrepancy can be observed by combining static and dynamic scattering experiments. (author). 10 refs

  16. All-solution processed polymer light-emitting diodes with air stable metal-oxide electrodes

    NARCIS (Netherlands)

    Bruyn, P. de; Moet, D.J.D.; Blom, P.W.M.

    2012-01-01

    We present an all-solution processed polymer light-emitting diode (PLED) using spincoated zinc oxide (ZnO) and vanadium pentoxide (V2O5) as electron and hole injecting contact, respectively. We compare the performance of these devices to the standard PLED design using PEDOT:PSS as anode and Ba/Al as

  17. Understanding diffusion of intrinsically disordered proteins in polymer solutions: A disorder plus collapse model

    Directory of Open Access Journals (Sweden)

    Juan Wang

    2017-11-01

    Full Text Available Understanding diffusion of intrinsically disordered proteins (IDPs under crowded environments is of ubiquitous importance to modelling related dynamics in biological systems. In the present work, we proposed a theoretical framework to study the diffusion behavior of IDPs in polymer solutions. IDP is modeled as an ensemble of particles with a wide range of gyration radius subject to Flory-Fisk distribution, where the collapse effect which leads to the shrink of IDP due to polymer crowding is included. The diffusion coefficient of IDP is calculated as the average, denoted by 〈D〉, over the values of the particle samples. By properly incorporating the scaling relations for diffusion coefficient of nanoparticle (NP in polymer solutions, we are able to evaluate 〈D〉 straightforwardly and reveal the disorder and collapse effects on IDP’s diffusion in an explicit manner. Particular attentions are paid on comparison between the diffusion coefficient of an IDP and that of a NP. Results demonstrate that both disorder and collapse can enhance IDP diffusion rate. Our analysis shows that the crossover behavior reported by experiments can be actually a general phenomenon, namely, while a NP with smaller size than that of an IDP diffuses faster in simple solutions, the IDP may become the faster one under crowded conditions. We apply our theory to analyze the diffusion of several types of IDP in a few different polymer solutions. Good agreements between the theoretical results and the experimental data are obtained.

  18. Statistical Investigation on Coherent Vortex Structure in Turbulent Drag Reducing Channel Flow with Blown Polymer Solution

    International Nuclear Information System (INIS)

    Ishitsuka, Shota; Motozawa, Masaaki; Kawaguchi, Yasuo; Iwamoto, Kaoru; Ando, Hirotomo; Senda, Tetsuya

    2011-01-01

    Coherent vortex structure in turbulent drag-reducing channel flow with blown polymer solution from the wall was investigated. As a statistical analysis, we carried out Galilean decomposition, swirling strength and linear stochastic estimation of the PIV data obtained by the PIV measurement in x – y plane. Reynolds number based on bulk velocity and channel height was set to 40000. As a result, the angle of shear layer that cleared up by using Galilean decomposition becomes small in the drag-reducing flow. Q3 events were observed near the shear layer. In addition, as a result of linear stochastic estimation (LSE) based on swirling strength, we confirmed that the velocity under the vortex core is strong in the water flow. This result shows Q2 (ejection) are dominant in the water flow. However, in the drag-reducing flow with blown polymer solution, the velocity above the vortex core become strong, that is, Q4 (sweep) events are relatively strong around the vortex core. This is the result of Q4 events to come from the channel center region because the polymer solution does not exist in this region. The typical structure like this was observed in the drag -reducing flow with blown polymer solution from the wall.

  19. Formation and thermodynamic stability of (polymer + porphyrin) supramolecular structures in aqueous solutions

    International Nuclear Information System (INIS)

    Costa, Viviana C.P. da; Hwang, Barrington J.; Eggen, Spencer E.; Wallace, Megan J.; Annunziata, Onofrio

    2014-01-01

    Highlights: • Thermodynamic stability of a (polymer + porphyrin) supramolecular structure was characterized. • Isothermal titration calorimetry provided two ways to determine reaction enthalpies. • Exothermic (polymer + porphyrin) binding competes with porphyrin self-association. • (Polymer + porphyrin) binding is entropically favored with respect to porphyrin self-association. • Spectral shifts show importance of porphyrin central hydrogens in polymer binding. - Abstract: Optical properties of porphyrins can be tuned through (polymer + porphyrin) (host + guest) binding in solution. This gives rise to the formation of supramolecular structures. In this paper, the formation, thermodynamic stability and spectroscopic properties of (polymer + porphyrin) supramolecular structures and their competition with porphyrin self-association were investigated by both isothermal titration calorimetry (ITC) and absorption spectroscopy. Specifically, reaction enthalpies and equilibrium constants were measured for meso-tetrakis(4-sulfonatophenyl) porphyrin (TPPS) self-association and TPPS binding to the polymer poly(vinylpyrrolidone) (PVP, 40 kg/mol) in aqueous solutions at pH 7 and three different temperatures (12, 25 and 37 °C). ITC, compared to spectroscopic techniques, provides two independent means to determine reaction enthalpies: direct measurements and Van’t Hoff plot. This was used as a criterion to assess that (1) self-association of TPPS is limited to the formation of dimers and (2) TPPS binds to PVP in its monomeric state only. The formation of TPPS dimers and (PVP + TPPS) supramolecular structures are both enthalpically driven. However, (polymer + porphyrin) binding was found to be entropically favored compared to dimerization. Furthermore, the reaction enthalpies of these two processes significantly depend on temperature. This behavior was attributed to hydrophobic interactions. Finally, the limiting absorption spectra of monomeric, dimeric and polymer

  20. Dilute and Semidilute Solutions of a Nonionic, Rigid, Water-soluble Polymer

    Science.gov (United States)

    Russo, Paul; Huberty, Wayne; Zhang, Donghui; Water-Soluble Rodlike Polymer Team Collaboration

    2014-03-01

    The solution physics of random polymer chains was established largely on the behavior of commercial polymers such as polystyrene for organic solvents or nonionic poly(ethyleneoxide) for aqueous solvents. Not only are these materials widely available for industrial use, they can be synthesized to be essentially monodisperse. When it comes to stiff polymers, good choices are few and less prone to be used in industrial applications. Much was learned from polypeptides such as poly(benzylglutamate) or poly(stearylglutamate) in polar organic solvents and nonpolar organic solvents, respectively, but aqueous systems generally require charge. Poly(Nɛ-2-[2-(2-Methoxyethoxy) ethoxy]acetyl-L-Lysine) a.k.a. PEGL was pioneered by Deming and coworkers. In principle, PEGL provides a convenient platform from which to study stiff polymer behavior--phase relations, dynamics, liquid crystal formation and gelation--all with good molecular weight control and uniformity and without electrical charge. Still, a large gap in knowledge exists between PEGL and traditional rodlike polymer systems. To narrow this gap, dynamic and static scattering, circular dichroism, and viscosity measurements have been made in dilute and semidilute solutions as necessary preliminaries for lyotropic liquid crystalline and gel phases. Supported by NSF DMR 1306262. Department of Chemistry and Macromolecular Studies Group. Current address: Georgia Institute of Technology, School of Materials Science and Engineering.

  1. Removal of Parabens from Aqueous Solution Using β-Cyclodextrin Cross-Linked Polymer

    Directory of Open Access Journals (Sweden)

    Mhd Radzi Bin Abas

    2010-09-01

    Full Text Available The removal of four parabens, methyl-, ethyl-, propyl-, and benzyl-paraben, by β-cyclodextrin (β-CD polymer from aqueous solution was studied. Different β-CD polymers were prepared by using two cross-linkers, i.e., hexamethylene diisocyanate (HMDI and toluene-2,6-diisocyanate (TDI, with various molar ratios of cross-linker. β-CD-HMDI polymer with molar ratio of 1:7 and β-CD-TDI polymer with ratio 1:4 gave the highest adsorption of parabens among the β-CD-HMDI and β-CD-TDI series, and were subsequently used for further studies. The adsorption capacity of β-CD-HMDI is 0.0305, 0.0376, 0.1854 and 0.3026 mmol/g for methyl-, ethyl-, propyl-, and benzyl-paraben, respectively. β-CD-TDI have higher adsorption capacities compared with β-CD-HMDI, the adsorption capacity are 0.1019, 0.1286, 0.2551, and 0.3699 mmol/g methyl-, ethyl-, propyl-, and benzyl-paraben respectively. The parameters studied were adsorption capacity, water retention, and reusability. Role of both cross-linker in adsorption, hydrophobicity of polymers, and adsorption capacity of different parabens were compared and discussed. All experiments were conducted in batch adsorption technique. These polymers were applied to real samples and showed positive results.

  2. Solution-processable ambipolar diketopyrrolopyrrole-selenophene polymer with unprecedentedly high hole and electron mobilities.

    Science.gov (United States)

    Lee, Junghoon; Han, A-Reum; Kim, Jonggi; Kim, Yiho; Oh, Joon Hak; Yang, Changduk

    2012-12-26

    There is a fast-growing demand for polymer-based ambipolar thin-film transistors (TFTs), in which both n-type and p-type transistor operations are realized in a single layer, while maintaining simplicity in processing. Research progress toward this end is essentially fueled by molecular engineering of the conjugated backbones of the polymers and the development of process architectures for device fabrication, which has recently led to hole and electron mobilities of more than 1.0 cm(2) V(-1) s(-1). However, ambipolar polymers with even higher performance are still required. By taking into account both the conjugated backbone and side chains of the polymer component, we have developed a dithienyl-diketopyrrolopyrrole (TDPP) and selenophene containing polymer with hybrid siloxane-solubilizing groups (PTDPPSe-Si). A synergistic combination of rational polymer backbone design, side-chain dynamics, and solution processing affords an enormous boost in ambipolar TFT performance, resulting in unprecedentedly high hole and electron mobilities of 3.97 and 2.20 cm(2) V(-1) s(-1), respectively.

  3. Diffusion of drag-reducing polymer solutions within a rough-walled turbulent boundary layer

    Science.gov (United States)

    Elbing, Brian R.; Dowling, David R.; Perlin, Marc; Ceccio, Steven L.

    2010-04-01

    The influence of surface roughness on diffusion of wall-injected, drag-reducing polymer solutions within a turbulent boundary layer was studied with a 0.94 m long flat-plate test model at speeds of up to 10.6 m s-1 and Reynolds numbers of up to 9×106. The surface was hydraulically smooth, transitionally rough, or fully rough. Mean concentration profiles were acquired with planar laser induced fluorescence, which was the primary flow diagnostic. Polymer concentration profiles with high injection concentrations (≥1000 wppm) had the peak concentration shifted away from the wall, which was partially attributed to a lifting phenomenon. The diffusion process was divided into three zones—initial, intermediate, and final. Studies of polymer injection into a polymer ocean at concentrations sufficient for maximum drag reduction indicated that the maximum initial zone length is of the order of 100 boundary layer thicknesses. The intermediate zone results indicate that friction velocity and roughness height are important scaling parameters in addition to flow and injection conditions. Lastly, the current results were combined with those in Petrie et al. ["Polymer drag reduction with surface roughness in flat-plate turbulent boundary layer flow," Exp. Fluids 35, 8 (2003)] to demonstrate that the influence of polymer degradation increases with increased surface roughness.

  4. Interaction Mechanisms between Air Bubble and Molybdenite Surface: Impact of Solution Salinity and Polymer Adsorption.

    Science.gov (United States)

    Xie, Lei; Wang, Jingyi; Yuan, Duowei; Shi, Chen; Cui, Xin; Zhang, Hao; Liu, Qi; Liu, Qingxia; Zeng, Hongbo

    2017-03-07

    The surface characteristics of molybdenite (MoS 2 ) such as wettability and surface interactions have attracted much research interest in a wide range of engineering applications, such as froth flotation. In this work, a bubble probe atomic force microscope (AFM) technique was employed to directly measure the interaction forces between an air bubble and molybdenite mineral surface before/after polymer (i.e., guar gum) adsorption treatment. The AFM imaging showed that the polymer coverage on the surface of molybdenite could achieve ∼5.6, ∼44.5, and ∼100% after conditioning in 1, 5, and 10 ppm polymer solution, respectively, which coincided with the polymer coverage results based on contact angle measurements. The electrolyte concentration and surface treatment by polymer adsorption were found to significantly affect bubble-mineral interaction and attachment. The experimental force results on bubble-molybdenite (without polymer treatment) agreed well with the calculations using a theoretical model based on the Reynolds lubrication theory and augmented Young-Laplace equation including the effect of disjoining pressure. The overall surface repulsion was enhanced when the NaCl concentration decreased from 100 to 1 mM, which inhibited the bubble-molybdenite attachment. After conditioning the molybdenite surface in 1 ppm polymer solution, it was more difficult for air bubbles to attach to the molybdenite surface due to the weakened hydrophobic interaction with a shorter decay length. Increasing the polymer concentration to 5 ppm effectively inhibited bubble attachment on mineral surface, which was mainly due to the much reduced hydrophobic interaction as well as the additional steric repulsion between the extended polymer chains and bubble surface. The results provide quantitative information on the interaction mechanism between air bubbles and molybdenite mineral surfaces on the nanoscale, with useful implications for the development of effective polymer

  5. Engineering polyelectrolyte multilayer structure at the nanometer length scale by tuning polymer solution conformation.

    Science.gov (United States)

    Boddohi, Soheil; Killingsworth, Christopher; Kipper, Matt

    2008-03-01

    Chitosan (a weak polycation) and heparin (a strong polyanion) are used to make polyelectrolyte multilayers (PEM). PEM thickness and composition are determined as a function of solution pH (4.6 to 5.8) and ionic strength (0.1 to 0.5 M). Over this range, increasing pH increases the PEM thickness; however, the sensitivity to changes in pH is a strong function of ionic strength. The PEM thickness data are correlated to the polymer conformation in solution. Polyelectrolyte conformation in solution is characterized by gel permeation chromatography (GPC). The highest sensitivity of PEM structure to pH is obtained at intermediate ionic strength. Different interactions govern the conformation and adsorption phenomena at low and high ionic strength, leading to reduced sensitivity to solution pH at extreme ionic strengths. The correspondence between PEM thickness and polymer solution conformation offers opportunities to tune polymer thin film structure at the nanometer length scale by controlling simple, reproducible processing conditions.

  6. Chain propagator, mass, and universality in polymer solutions from Brownian relativity

    International Nuclear Information System (INIS)

    Mezzasalma, Stefano A.

    2005-01-01

    A Lagrangian theory for single chains in polymer solutions is addressed via a recent Brownian relativity. By employing generalized diffusive coordinates, statements of covariance and diffusivity invariance result into free particle Lagrangians, where mass turns out to rise as a universal spacetime property. It descends from lowering diffusivity (or curving spacetime), so identifying a mechanism which conceptually resemble those ruling macromolecular scaling laws. An extended chain propagator recovers the Gaussian end-to-end distribution and, in the limits of time-like and space-like orbits, the dualism for diffusive paths and polymer random-walks

  7. Structure of amorphous sulfur

    CSIR Research Space (South Africa)

    Eichinger, BE

    2001-06-01

    Full Text Available The lambda-transition of elemental sulfur occurring at about 159°C has long been associated with the conversion of cyclic S8 rings (c-S8) to amorphous polymer (a-S) via a ring opening polymerization. It is demonstrated, with the use of both density...

  8. Hydrogenated amorphous carbon next deposit after heat treatment

    International Nuclear Information System (INIS)

    Salancon, E.; Durbeck, T.; Schwarz-Selinger, T.; Jacob, W.

    2006-01-01

    One of the main safety problems in the ITER tokamak project is the tritium adsorption in the reactor walls and in particular the deposits which appear after the plasma discharge. These deposits are amorphous hydrogenated carbon films, type polymer (soft a-C:H). The heating of these deposits with a pulse laser is a proposed solution for the tritium desorption. Meanwhile, Gibson and al show that in experimental conditions, products are deposed on the walls before entering the mass spectrometer. The authors present thermo-desorption spectra of different amorphous carbon films. (A.L.B.)

  9. Leaching of irradiated polymers: solution characterization and actinides complexation

    International Nuclear Information System (INIS)

    Fromentin, Elodie

    2017-01-01

    The first aim of this work is to study the degradation of an industrial poly-esterurethane (PURm) by radio-oxidation and then by leaching in an alkaline aqueous solution. The second aim is to measure the complexing power of hydro-soluble degradation products (HDP) with actinides. To reach these goals, PURm was first characterized and then radio-oxidized at room temperature with γ rays up to 10 MGy. Second, it was leached at pH 13.3 at different temperature values. Numerous analytical techniques were employed in order to characterize the HDP which were obtained. Europium(III) was used as an analogue of actinides(III) and the behavior of HDP with europium(III) was analyzed by time-resolved luminescence spectroscopy (TRLS). Whatever the dose received by PURm, adipic acid and butane-1,4-diol are the two main HDP in leachates. The leaching data acquired at 40 and 60 C, on the 1 MGy radio-oxidized PURm, correlate with the model given by Yoon et al. (1997). However, the data at room temperature (22 C in average) are not in agreement with the model. Nevertheless, it seems that the plateau which was reached at long-term leaching is the same whatever the temperature used in this study. The results allow to conclude that the predominant mechanism occurring during the leaching of unirradiated and radio-oxidized PURm in an alkaline medium is the hydrolysis of the soft segments ester groups. The complexation of europium(III) by HDP in alkaline medium was demonstrated. The measurement of the complexing power and the identification of ligands was achieved under certain conditions. (author) [fr

  10. Effect of crystallization condition on the Microwave properties of Fe-based amorphous alloy flakes and polymer composites

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Byoung-Gi [Department of Advanced Metallic Materials, Korea Institute of Materials Science, 531 Changwondaero, Changwon, Kyungnam (Korea, Republic of); Hong, Soon-Ho; Sohn, Keun Yong; Park, Won-Wook [School of Nano Engineering, Inje University, 607 Obang-dong, Kimhae, Kyungnam (Korea, Republic of); Kwon, Sang-Kyun; Song, Yong-Sul [Amosense Co., 185-1 Sucham-ri, Tongjin-myun, Gimposi, Kyungkido (Korea, Republic of); Lee, Taek-Dong, E-mail: bgmoon@kims.re.k [Department of Materials Science and Engineering, Korea Insititute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon (Korea, Republic of)

    2009-01-01

    The electromagnetic (EM) wave absorption properties with a variation of crystallization temperature have been investigated in a sheet-type absorber made of the amorphous Fe{sub 73}Si{sub 16}B{sub 7}Nb{sub 3}Cu{sub 1}Finemet powder. With the variation of the annealing temperature, the magnetic and dielectric properties of the crystallized Fe-based absorber with a nano-structure were changed. The complex permittivity increased with increasing the annealing temperature, whereas the complex permeability was maximized after annealing at 530 deg. C for 1 hour. The absolute value of the reflection parameter, |S{sub 11}|, increased with increasing annealing temperature of the nanocrystalline alloy powder. On the contrary, the transmission one, |S{sub 21}|, showed the highest value after annealing at 530 deg. C for 1 hour, which is regarded as the optimum temperature for the improvement of EM wave absorption properties.

  11. Enhanced efficiency of hybrid amorphous silicon solar cells based on single-walled carbon nanotubes/polymer composite thin film.

    Science.gov (United States)

    Rajanna, Pramod Mulbagal; Gilshteyn, Evgenia; Yagafarov, Timur; Alekseeva, Alena; Anisimov, Anton; Sergeev, Oleg; Neumueller, Alex; Bereznev, Sergei; Maricheva, Jelena; Nasibulin, Albert

    2018-01-09

    We report a simple approach to fabricate hybrid solar cells (HSCs) based on a single-walled carbon nanotube (SWCNT) film and a thin film hydrogenated amorphous silicon (a-Si:H). Randomly oriented high quality SWCNTs with an enhanced conductivity by means of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate are used as a window layer and a front electrode. A series of HSCs are fabricated in ambient conditions with different SWCNT film thicknesses. The polymethylmethacrylate layer drop-casted on fabricated HSCs reduces the reflection fourfold and enhances the short-circuit Jsc, open-circuit Voc, and efficiency by nearly 10%. A state-of-the-art J-V performance is shown for SWCNT/a-Si HSC with an open-circuit voltage of 900 mV and efficiency of 3.4% under simulated one-sun AM 1.5G direct illumination. © 2018 IOP Publishing Ltd.

  12. Enhanced efficiency of hybrid amorphous silicon solar cells based on single-walled carbon nanotubes and polymer composite thin film

    Science.gov (United States)

    Rajanna, Pramod M.; Gilshteyn, Evgenia P.; Yagafarov, Timur; Aleekseeva, Alena K.; Anisimov, Anton S.; Neumüller, Alex; Sergeev, Oleg; Bereznev, Sergei; Maricheva, Jelena; Nasibulin, Albert G.

    2018-03-01

    We report a simple approach to fabricate hybrid solar cells (HSCs) based on a single-walled carbon nanotube (SWCNT) film and thin film hydrogenated amorphous silicon (a-Si:H). Randomly oriented high-quality SWCNTs with conductivity enhanced by means of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate are used as a window layer and a front electrode. A series of HSCs are fabricated in ambient conditions with varying SWCNT film thicknesses. The polymethylmethacrylate layer drop-casted on fabricated HSCs reduces the reflection fourfold and enhances the short-circuit J sc , open-circuit V oc , and efficiency by nearly 10%. A state-of-the-art J-V performance is shown for SWCNT/a-Si HSC with an open-circuit voltage of 900 mV and an efficiency of 3.4% under simulated one-sun AM 1.5 G direct illumination.

  13. Self-Assembly of Telechelic Tyrosine End-Capped PEO Star Polymers in Aqueous Solution.

    Science.gov (United States)

    Edwards-Gayle, Charlotte J C; Greco, Francesca; Hamley, Ian W; Rambo, Robert P; Reza, Mehedi; Ruokolainen, Janne; Skoulas, Dimitrios; Iatrou, Hermis

    2018-01-08

    We investigate the self-assembly of two telechelic star polymer-peptide conjugates based on poly(ethylene oxide) (PEO) four-arm star polymers capped with oligotyrosine. The conjugates were prepared via N-carboxy anhydride-mediated ring-opening polymerization from PEO star polymer macroinitiators. Self-assembly occurs above a critical aggregation concentration determined via fluorescence probe assays. Peptide conformation was examined using circular dichroism spectroscopy. The structure of self-assembled aggregates was probed using small-angle X-ray scattering and cryogenic transmission electron microscopy. In contrast to previous studies on linear telechelic PEO-oligotyrosine conjugates that show self-assembly into β-sheet fibrils, the star architecture suppresses fibril formation and micelles are generally observed instead, a small population of fibrils only being observed upon pH adjustment. Hydrogelation is also suppressed by the polymer star architecture. These peptide-functionalized star polymer solutions are cytocompatible at sufficiently low concentration. These systems present tyrosine at high density and may be useful in the development of future enzyme or pH-responsive biomaterials.

  14. Pattern Formation During Phase Separation of Polymer-Ionic Liquid Co-Solutions

    Science.gov (United States)

    Meng, Zhiyong; Osuji, Chinedum

    2010-03-01

    Co-solutions of polystyrene (PS) with a 1-butyl-3-methylimidazolium based ionic liquid (IL) in DMF phase separated into IL-rich and PS-rich domains on solvent evaporation. Over a limited range of polymer molecular weights and substrate temperatures, a variety of striped and cellular or polygonal structures were found on the resulting film surface, as visualized using bright-field and phase-contrast optical microscopy. This effect appears to be due to a Benard-Marangoni instability at the free surface of the liquid film as it undergoes evaporation, setting up convection rolls inside the fluid which become locked in place as the system vitrifies on solvent removal. Differential scanning calorimetry shows that the IL does not significantly plasticize the polymer, suggesting that the viscosity of the polystyrene solution itself controls the formation of this instability.

  15. γ-radiation resistance of amorphous films of a-Si1-xGex:H solid solution

    International Nuclear Information System (INIS)

    Najafov, B.A.; Isakov, G.I.; Figarov, V.R.

    2004-01-01

    Full text: a-Si 1-x Ge x :H solid solution amorphous films (with x=0.4; 0.7, H=17 at. %) were fabricated by the plasma-chemical deposition method 1 μm thick, at the substrate temperature of 200 deg. C, the rate of deposition was 0.1 A /s, and the distance between the target and the substrate was L∼25 cm. The dispersion process was conducted in a hydrogenous plasma medium, that had been obtained with the use of a magnetron and a RF field. Taken ESR spectra of a-Si 1-x Ge x :H at 80 K were asymmetric in form, inasmuch as they were composed of two kinds relating to free bonds of Si and Ge, respectively. At the same time the observed signal was not a simple superposition of the two signals (for Si and for Ge), since they violently interacted with each other and the resulting signal in the intervening interval aimed to assume the form of a sole line. Because of this the observed spectrum on the left and on the right could be depicted by a superposition of the two signal: with g-factor of g=2.004-2.006 and the line width of 51-65 G and with g=2.018-2.022 and 73-86 G relating to the silicon and germanium free bonds, respectively. In this way it could be evaluated densities of Si and Ge free bonds, taken separately. But in accordance with computation of molecular orbitals in a-Si 1-x Ge x :H, the presence of atoms, adjacent to the orbitals, almost does not alter g-value of ESR-signals from both Si and Ge free bonds. By the IR absorption spectrum determining a number of Si-H bonds, and also a number of Ge-H bonds, it may assert that a number of Ge free bonds is 8-10 times larger than that of Si. It is proved that in a-Si 1 x Ge x : H films H atoms are mainly bound to Si atoms and so a total number of H is reduced with increasing of Ge content. That stands for the density of Ge free bonds decreases a number of H atoms, bound to Ge, but it does not a number of H atoms, bound to Si. This fact is also confirmed by ESR investigations. ESR investigations in a-Si 1-x Ge x :H

  16. A new scaling for the rotational diffusion of molecular probes in polymer solutions.

    Science.gov (United States)

    Qing, Jing; Chen, Anpu; Zhao, Nanrong

    2017-12-13

    In the present work, we propose a new scaling form for the rotational diffusion coefficient of molecular probes in semi-dilute polymer solutions, based on a theoretical study. The mean-field theory for depletion effect and semi-empirical scaling equation for the macroscopic viscosity of polymer solutions are properly incorporated to specify the space-dependent concentration and viscosity profiles in the vicinity of the probe surface. Following the scheme of classical fluid mechanics, we numerically evaluate the shear torque exerted on the probes, which then allows us to further calculate the rotational diffusion coefficient D r . Particular attention is given to the scaling behavior of the retardation factor R rot ≡ D/D r with D being the diffusion coefficient in pure solvent. We find that R rot has little relevance to the macroscopic viscosity of the polymer solution, while it can be well featured by the characteristic length scale r h /δ, i.e. the ratio between the hydrodynamic radius of the probe r h and the depletion thickness δ. Correspondingly, we obtain a novel scaling form for the rotational retardation factor, following R rot = exp[a(r h /δ) b ] with rather robust parameters of a ≃ 0.51 and b ≃ 0.56. We apply the theory to an extensive calculation for various probes in specific polymer solutions of poly(ethylene glycol) (PEG) and dextran. Our theoretical results show good agreements with the experimental data, and clearly demonstrate the validity of the new scaling form. In addition, the difference of the scaling behavior between translational and rotational diffusions is clarified, from which we conclude that the depletion effect plays a more significant role on the local rotational diffusion rather than the long-range translation diffusion.

  17. Dynamical scaling in polymer solutions investigated by the neutron spin echo technique

    International Nuclear Information System (INIS)

    Richter, D.; Ewen, B.

    1979-01-01

    Chain dynamics in polymer solutions was investigated by means of the recently developed neutron spin echo spectroscopy. - By this technique, it was possible for the first time to verify unambiguously the scaling predictions of the Zimm model in the case of single chain behaviour and to observe the cross over to many chain behaviour. The segmental diffusion of single chains exhibits deviations from a simple exponential law, indicating the importance of memory effects. (orig.) [de

  18. Solute induced relaxation in glassy polymers: Experimental measurements and nonequilibrium thermodynamic model

    International Nuclear Information System (INIS)

    Minelli, Matteo; Doghieri, Ferruccio

    2014-01-01

    Data for kinetics of mass uptake from vapor sorption experiments in thin glassy polymer samples are here interpreted in terms of relaxation times for volume dilation. To this result, both models from non-equilibrium thermodynamics and from mechanics of volume relaxation contribute. Different kind of sorption experiments have been considered in order to facilitate the direct comparison between kinetics of solute induced volume dilation and corresponding data from process driven by pressure or temperature jumps

  19. Theory of the high-frequency limiting viscosity of a dilute polymer solution. Pt. 2

    Energy Technology Data Exchange (ETDEWEB)

    Doi, M; Nakajima, H; Wada, Y

    1976-06-01

    High-frequency limiting viscosities of dilute polymer solutions are calculated on the basis of the author's previous theory for (1) necklace model of a chain with constant bond length and bond angle under a hindering rotational potential, and (2) broken rod model consisting of N rods with equal length connected by universal joints. Exact treatment is possible for a once-broken rod model, but the Monte Carlo method is used in the other calculations.

  20. Stacking layered structure of polymer light emitting diodes prepared by evaporative spray deposition using ultradilute solution for improving carrier balance

    International Nuclear Information System (INIS)

    Aoki, Youichi; Shakutsui, Masato; Fujita, Katsuhiko

    2009-01-01

    Polymer light-emitting diodes (PLEDs) with staking layered structures are prepared by the evaporative spray deposition using ultradilute solution (ESDUS) method, which has enabled forming a polymer layer onto another polymer layer even if both polymers are soluble in a solvent used for the preparation. By this method, polymers having various HOMO and LUMO levels can be stacked as a hole transport layer, an emitting layer and an electron transport layer as commonly employed in small molecule-based organic light emitting diodes. Here we demonstrated that a PLED having a tri-layer structure using three kinds of polymers showed significant improvement in quantum efficiency compared with those having a single or bi-layer structure of corresponding polymers.

  1. Ultra-Flexible, Invisible Thin-Film Transistors Enabled by Amorphous Metal Oxide/Polymer Channel Layer Blends

    Science.gov (United States)

    2015-02-25

    coordination num- bers (CNs), bond lengths , and Debye –Waller factors from Equation ( 1) : [ 45 ] ( ) ( ) sin 2 i i 0 2 i 2 i i 2 ( ) 2 j i 2 2 k N f k S...through a shadow mask (channel length L = 50 µm, channel width W = 1 mm). The newly developed In 2 O 3 : x %PVP semiconducting fi lms were fi rst...coordination numbers, In–O bond lengths , and σ 2 values for the indicated fi lms. e,f) X-ray photoelectron spectroscopy (XPS) of In 2 O 3 :polymer fi

  2. Polymer-based oral rehydration solution for treating acute watery diarrhoea

    Science.gov (United States)

    Gregorio, Germana V; Gonzales, Maria Liza M; Dans, Leonila F; Martinez, Elizabeth G

    2016-01-01

    Background Acute diarrhoea is one of the main causes of morbidity and mortality among children in low-income countries. Glucose-based oral rehydration solution (ORS) helps replace fluid and prevent further dehydration from acute diarrhoea. Since 2004, the World Health Organization (WHO) has recommended the osmolarity of less than 270 mOsm/L (ORS ≤ 270) versus greater than 310 mOsm/L formulation (ORS ≥ 310). Polymer-based ORS (for example, prepared using rice or wheat) slowly releases glucose and may be superior to glucose-based ORS. Objectives To compare polymer-based oral rehydration solution (polymer-based ORS) with glucose-based oral rehydration solution (glucose-based ORS) for treating acute watery diarrhoea. Search methods We searched the following sources up to 5 September 2016: the Cochrane Infectious Diseases Group (CIDG) Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2016, Issue 9), MEDLINE (1966 to 5 September 2016), EMBASE (1974 to 5 September 2016), LILACS (1982 to 5 September 2016), and mRCT (2007 to 5 September 2016). We also contacted researchers, organizations, and pharmaceutical companies, and searched reference lists. Selection criteria We included randomized controlled trials (RCTs) of people with acute watery diarrhoea (cholera and non-cholera associated) that compared polymer-based and glucose-based ORS (with identical electrolyte contents). Data collection and analysis Two review authors independently assessed the search results and risk of bias, and extracted data. In multiple-treatment arms with two or more treatment groups, we combined outcomes as appropriate and compared collectively with the control group. Main results Thirty-five trials that included 4284 participants met the inclusion criteria: 28 trials exclusively included children, five included adults, and two included both adults and children. Polymer-based ORS versus glucose-based ORS (osmolarity ≤ 270) Eight trials

  3. INFLUENCE OF THE COOLING RATE AND THE BLEND RATIO ON THE PHYSICAL STABILTIY OF CO-AMORPHOUS NAPROXEN/INDOMETHACIN

    DEFF Research Database (Denmark)

    Beyer, Andreas; Grohganz, Holger; Löbmann, Korbinian

    2016-01-01

    Co-amorphisation represents a promising approach to increase the physical stability and dissolution rate of amorphous active pharmaceutical ingredients (APIs) as an alternative to polymer glass solutions. For amorphous and co-amorphous systems, it is reported that the preparation method and the b......Co-amorphisation represents a promising approach to increase the physical stability and dissolution rate of amorphous active pharmaceutical ingredients (APIs) as an alternative to polymer glass solutions. For amorphous and co-amorphous systems, it is reported that the preparation method...... and the blend ratio play major roles with regard to the resulting physical stability. Therefore, in the present study, co-amorphous naproxen-indomethacin (NAP/IND) was prepared by melt-quenching at three different cooling rates and at ten different NAP/IND blend ratios. The samples were analyzed using XRPD...... and FTIR, both directly after preparation and during storage to investigate their physical stabilities. All cooling methods led to fully amorphous samples, but with significantly different physical stabilities. Samples prepared by fast cooling had a higher degree of crystallinity after 300 d of storage...

  4. Surface modification of aluminum nitride by polysilazane and its polymer-derived amorphous silicon oxycarbide ceramic for the enhancement of thermal conductivity in silicone rubber composite

    Science.gov (United States)

    Chiu, Hsien Tang; Sukachonmakul, Tanapon; Kuo, Ming Tai; Wang, Yu Hsiang; Wattanakul, Karnthidaporn

    2014-02-01

    Polysilazane (PSZ) and its polymer-derived amorphous silicon oxycarbide (SiOC) ceramic were coated on aluminum nitride (AlN) by using a dip-coating method to allow moisture-crosslinking of PSZ on AlN, followed by heat treatment at 700 °C in air to convert PSZ into SiOC on AlN. The results from FTIR, XPS and SEM indicated that the surface of AlN was successfully coated by PSZ and SiOC film. It was found that the introduction of PSZ and SiOC film help improve in the interfacial adhesion between the modified AlN (PSZ/AlN and SiOC/AlN) and silicone rubber lead to the increase in the thermal conductivity of the composites since the thermal boundary resistance at the filler-matrix interface was decreased. However, the introduction of SiOC as an intermediate layer between AlN and silicone rubber could help increase the thermal energy transport at the filler-matrix interface rather than using PSZ. This result was due to the decrease in the surface roughness and thickness of SiOC film after heat treatment at 700 °C in air. Thus, in the present work, a SiOC ceramic coating could provide a new surface modification for the improvement of the interfacial adhesion between the thermally conductive filler and the matrix in which can enhance the thermal conductivity of the composites.

  5. Physicochemical characterization of atorvastatin calcium/ezetimibe amorphous nano-solid dispersions prepared by electrospraying method.

    Science.gov (United States)

    Jahangiri, Azin; Barzegar-Jalali, Mohammad; Javadzadeh, Yousef; Hamishehkar, Hamed; Adibkia, Khosro

    2017-09-01

    In the present study, electrospraying was applied as a novel method for the fabrication of amorphous nano-solid dispersions (N-SDs) of atorvastatin calcium (ATV), ezetimibe (EZT), and ATV/EZT combination as poorly water-soluble drugs. N-SDs were prepared using polyvinylpyrrolidone K30 as an amorphous carrier in 1:1 and 1:5 drug to polymer ratios and the total solid (including drug and polymer) concentrations of 10 and 20% (w/v). The prepared formulations were further investigated for their morphological, physicochemical, and dissolution properties. Scanning electron microscopy studies indicated that the morphology and diameter of the electrosprayed samples (ESs) were influenced by the solution concentration and drug:polymer ratio, so that an increase in the solution concentration resulted in fiber formation while an increase in the polymer ratio led to enhancement of the particle diameter. Differential scanning calorimetry and X-ray powder diffraction studies together with in vitro dissolution test revealed that the ESs were present in an amorphous form with improved dissolution properties. Infrared spectroscopic studies showed hydrogen-bonding interaction between the drug and polymer in ESs. Since the electrospraying method benefits from the both amorphization and nanosizing effect, this novel approach seems to be an efficient method for the fabrication of N-SDs of poorly water-soluble drugs.

  6. Atmospheric Pressure Plasma Jet Treatment of Poly-ε-caprolactone Polymer Solutions To Improve Electrospinning.

    Science.gov (United States)

    Grande, Silvia; Van Guyse, Joachim; Nikiforov, Anton Y; Onyshchenko, Iuliia; Asadian, Mahtab; Morent, Rino; Hoogenboom, Richard; De Geyter, Nathalie

    2017-09-27

    An atmospheric pressure plasma jet (APPJ) specifically designed for liquid treatment has been used in this work to improve the electrospinnability of a 5 w/v % solution of poly-ε-caprolactone (PCL) in a mixture of chloroform and N,N-dimethylformamide. Untreated PCL solutions were found to result in nonuniform fibers containing a large number of beads, whereas plasma-treated solutions (exposure time of 2-5 min) enabled the generation of beadless, uniform nanofibers with an average diameter of 450 nm. This enhanced electrospinnability was found to be mainly due to the highly increased conductivity of the plasma-modified PCL solutions. Consequently, more stretching of the polymer jet occurred during electrospinning, leading to the generation of bead-free fibers. Plasma treatment also results in an increased viscosity and decreased pH values. To explain these observed changes, optical emission spectroscopy (OES) has been used to examine the excited species present in the APPJ in contact with the PCL solution. This study revealed that the peaks attributed to H, CH, CH 2 , and C 2 species could be responsible for the degradation of solvent molecules and/or PCL structures during the plasma treatment. Size exclusion chromatography and X-ray photoelectron spectroscopy results showed that the molecular weight and the chemical composition of PCL were not significantly affected by the APPJ treatment. Plasma exposure mainly results in the degradation of the solvent molecules instead of modifying the PCL macromolecules, preserving the original polymer as much as possible. A hypothesis for the observed macroscopic changes in viscosity and pH values could be the generation of new chemical species such as HCl and/or HNO 3 . These species are characterized by their high conductivity, low pH values, and strong polarity and could enhance the solvent quality for PCL, leading to the expansion of the polymer coil, which could in turn explain the observed enhanced viscosity after plasma

  7. Amorphization within the tablet

    DEFF Research Database (Denmark)

    Doreth, Maria; Hussein, Murtadha Abdul; Priemel, Petra A.

    2017-01-01

    , the feasibility of microwave irradiation to prepare amorphous solid dispersions (glass solutions) in situ was investigated. Indomethacin (IND) and polyvinylpyrrolidone K12 (PVP) were tableted at a 1:2 (w/w) ratio. In order to study the influence of moisture content and energy input on the degree of amorphization......, tablet formulations were stored at different relative humidity (32, 43 and 54% RH) and subsequently microwaved using nine different power-time combinations up to a maximum energy input of 90 kJ. XRPD results showed that up to 80% (w/w) of IND could be amorphized within the tablet. mDSC measurements...

  8. Modeling of the (liquid + liquid) equilibrium of polydisperse hyperbranched polymer solutions by lattice-cluster theory

    International Nuclear Information System (INIS)

    Enders, Sabine; Browarzik, Dieter

    2014-01-01

    Graphical abstract: - Highlights: • Calculation of the (liquid + liquid) equilibrium of hyperbranched polymer solutions. • Description of branching effects by the lattice-cluster theory. • Consideration of self- and cross association by chemical association models. • Treatment of the molar-mass polydispersity by the use of continuous thermodynamics. • Improvement of the theoretical results by the incorporation of polydispersity. - Abstract: The (liquid + liquid) equilibrium of solutions of hyperbranched polymers of the Boltorn type is modeled in the framework of lattice-cluster theory. The association effects are described by the chemical association models CALM (for self association) and ECALM (for cross association). For the first time the molar mass polydispersity of the hyperbranched polymers is taken into account. For this purpose continuous thermodynamics is applied. Because the segment-molar excess Gibbs free energy depends on the number average of the segment number of the polymer the treatment is more general than in previous papers on continuous thermodynamics. The polydispersity is described by a generalized Schulz–Flory distribution. The calculation of the cloud-point curve reduces to two equations that have to be numerically solved. Conditions for the calculation of the spinodal curve and of the critical point are derived. The calculated results are compared to experimental data taken from the literature. For Boltorn solutions in non-polar solvents the polydispersity influence is small. In all other of the considered cases polydispersity influences the (liquid + liquid) equilibrium considerably. However, association and polydispersity influence phase equilibrium in a complex manner. Taking polydispersity into account the accuracy of the calculations is improved, especially, in the diluted region

  9. Solution-processable MoOx nanocrystals enable highly efficient reflective and semitransparent polymer solar cells

    KAUST Repository

    Jagadamma, Lethy Krishnan

    2016-09-09

    Solution-manufacturing of organic solar cells with best-in-class power conversion efficiency (PCE) will require all layers to be solution-coated without compromising solar cell performance. To date, the hole transporting layer (HTL) deposited on top of the organic bulk heterojunction layer in the inverted architecture is most commonly an ultrathin (<10 nm) metal oxide layer prepared by vacuum-deposition. Here, we show that an alcohol-based nanocrystalline MoOx suspension with carefully controlled nanocrystal (NC) size can yield state of the art reflective and semitransparent solar cells. Using NCs smaller than the target HTL thickness (∼10 nm) can yield compact, pinhole-free films which result in highly efficient polymer:fullerene bulk heterojunction (BHJ) solar cells with PCE=9.5%. The solution processed HTL is shown to achieve performance parity with vacuum-evaporated HTLs for several polymer:fullerene combinations and is even shown to work as hole injection layer in polymer light emitting diodes (PLED). We also demonstrate that larger MoOx NCs (30–50 nm) successfully composite MoOx with Ag nanowires (NW) to form a highly conducting, transparent top anode with exceptional contact properties. This yields state-of-the-art semitransparent polymer: fullerene solar cells with PCE of 6.5% and overall transmission >30%. The remarkable performance of reflective and semitransparent OPVs is due to the uncommonly high fill factors achieved using a carefully designed strategy for implementation of MoOx nanocrystals as HTL materials. © 2016 Elsevier Ltd

  10. Temperature-induced phase separation and hydration in aqueous polymer solutions studied by NMR and IR spectroscopy: comparison of poly(N-vinylcaprolactam) and acrylamide-based polymers

    Czech Academy of Sciences Publication Activity Database

    Spěváček, Jiří; Dybal, Jiří

    2014-01-01

    Roč. 336, č. 1 (2014), s. 39-46 ISSN 1022-1360. [International IUPAC Conference on Polymer-Solvent Complexes and Intercalates /9./ - POLYSOLVAT-9. Kiev, 11.09.2012-14.09.2012] R&D Projects: GA ČR GA202/09/1281 Institutional support: RVO:61389013 Keywords : aqueous polymer solutions * FT-IR * NMR Subject RIV: CD - Macromolecular Chemistry

  11. Entanglements in Marginal Solutions: A Means of Tuning Pre-Aggregation of Conjugated Polymers with Positive Implications for Charge Transport

    KAUST Repository

    Hu, Hanlin

    2015-06-17

    The solution-processing of conjugated polymers, just like commodity polymers, is subject to solvent and molecular weight-dependent solubility, interactions and chain entanglements within the polymer, all of which can influence the crystallization and microstructure development in semi-crystalline polymers and consequently affect charge transport and optoelectronic properties. Disentanglement of polymer chains in marginal solvents was reported to work via ultrasonication, facilitating the formation of photophysically ordered polymer aggregates. In this contribution, we explore how a wide range of technologically relevant solvents and formulations commonly used in organic electronics influence chain entanglement and the aggregation behaviour of P3HT using a combination of rheological and spectrophotometric measurements. The specific viscosity of the solution offers an excellent indication of the degree of entanglements in the solution, which is found to be related to the solubility of P3HT in a given solvent. Moreover, deliberately disentangling the solution in the presence of solvophobic driving forces, leads consistently to formation of photophysically visible aggregates which is indicative of local and perhaps long range order in the solute. We show for a broad range of solvents and molecular weights that disentanglement ultimately leads to significant ordering of the polymer in the solid state and a commensurate increase in charge transport properties. In doing so we demonstrate a remarkable ability to tune the microstructure which has important implications for transport properties. We discuss its potential implications in the context of organic photovoltaics.

  12. Entanglements in Marginal Solutions: A Means of Tuning Pre-Aggregation of Conjugated Polymers with Positive Implications for Charge Transport

    KAUST Repository

    Hu, Hanlin; Zhao, Kui; Fernandes, Nikhil J.; Boufflet, Pierre; Bannock, James Henry; Yu, Liyang; de Mello, John C; Stingelin, Natalie; Heeney, Martin; Giannelis, Emmanuel P.; Amassian, Aram

    2015-01-01

    The solution-processing of conjugated polymers, just like commodity polymers, is subject to solvent and molecular weight-dependent solubility, interactions and chain entanglements within the polymer, all of which can influence the crystallization and microstructure development in semi-crystalline polymers and consequently affect charge transport and optoelectronic properties. Disentanglement of polymer chains in marginal solvents was reported to work via ultrasonication, facilitating the formation of photophysically ordered polymer aggregates. In this contribution, we explore how a wide range of technologically relevant solvents and formulations commonly used in organic electronics influence chain entanglement and the aggregation behaviour of P3HT using a combination of rheological and spectrophotometric measurements. The specific viscosity of the solution offers an excellent indication of the degree of entanglements in the solution, which is found to be related to the solubility of P3HT in a given solvent. Moreover, deliberately disentangling the solution in the presence of solvophobic driving forces, leads consistently to formation of photophysically visible aggregates which is indicative of local and perhaps long range order in the solute. We show for a broad range of solvents and molecular weights that disentanglement ultimately leads to significant ordering of the polymer in the solid state and a commensurate increase in charge transport properties. In doing so we demonstrate a remarkable ability to tune the microstructure which has important implications for transport properties. We discuss its potential implications in the context of organic photovoltaics.

  13. Carrier Transport Enhancement in Conjugated Polymers through Interfacial Self-Assembly of Solution-State Aggregates

    KAUST Repository

    Zhao, Kui

    2016-07-13

    We demonstrate that local and long range orders of poly(3-hexylthiophene) (P3HT) semicrystalline films can be synergistically improved by combining chemical functionalization of the dielectric surface with solution-state disentanglement and pre-aggregation of P3HT in a theta solvent, leading to a very significant enhancement of the field effect carrier mobility. The pre-aggregation and surface functionalization effects combine to enhance the carrier mobility nearly 100-fold as compared with standard film preparation by spin-coating, and nearly 10-fold increase over the benefits of pre-aggregation alone. In situ quartz crystal microbalance with dissipation (QCM-D) experiments reveal enhanced deposition of pre-aggregates on surfaces modified with an alkyl-terminated self-assembled monolayer (SAM) in comparison to un-aggregated polymer chains. Additional investigations reveal the combined pre-aggregation and surface functionalization significantly enhances local order of the conjugated polymer through planarization and extension of the conjugated backbone of the polymer which clearly translate to significant improvements of carrier transport at the semiconductor-dielectric interface in organic thin film transistors. This study points to opportunities in combining complementary routes, such as well-known pre-aggregation with substrate chemical functionalization, to enhance the polymer self-assembly and improve its interfacial order with benefits for transport properties.

  14. A salt water battery with high stability and charging rates made from solution processed conjugated polymers with polar side chains

    OpenAIRE

    Moia, Davide; Giovannitti, Alexander; Szumska, Anna A.; Schnurr, Martin; Rezasoltani, Elham; Maria, Iuliana P.; Barnes, Piers R. F.; McCulloch, Iain; Nelson, Jenny

    2017-01-01

    We report a neutral salt water based battery which uses p-type and n-type solution processed polymer films as the cathode and the anode of the cell. The specific capacity of the electrodes (approximately 30 mAh cm-3) is achieved via formation of bipolarons in both the p-type and n-type polymers. By engineering ethylene glycol and zwitterion based side chains attached to the polymer backbone we facilitate rapid ion transport through the non-porous polymer films. This, combined with efficient t...

  15. A Solution-Doped Polymer Semiconductor:Insulator Blend for Thermoelectrics

    KAUST Repository

    Kiefer, David; Yu, Liyang; Fransson, Erik; Gó mez, André s; Primetzhofer, Daniel; Amassian, Aram; Campoy-Quiles, Mariano; Mü ller, Christian

    2016-01-01

    Poly(ethylene oxide) is demonstrated to be a suitable matrix polymer for the solution-doped conjugated polymer poly(3-hexylthiophene). The polarity of the insulator combined with carefully chosen processing conditions permits the fabrication of tens of micrometer-thick films that feature a fine distribution of the F4TCNQ dopant:semiconductor complex. Changes in electrical conductivity from 0.1 to 0.3 S cm−1 and Seebeck coefficient from 100 to 60 μV K−1 upon addition of the insulator correlate with an increase in doping efficiency from 20% to 40% for heavily doped ternary blends. An invariant bulk thermal conductivity of about 0.3 W m−1 K−1 gives rise to a thermoelectric Figure of merit ZT ∼ 10−4 that remains unaltered for an insulator content of more than 60 wt%. Free-standing, mechanically robust tapes illustrate the versatility of the developed dopant:semiconductor:insulator ternary blends.

  16. A Solution-Doped Polymer Semiconductor:Insulator Blend for Thermoelectrics

    KAUST Repository

    Kiefer, David

    2016-09-01

    Poly(ethylene oxide) is demonstrated to be a suitable matrix polymer for the solution-doped conjugated polymer poly(3-hexylthiophene). The polarity of the insulator combined with carefully chosen processing conditions permits the fabrication of tens of micrometer-thick films that feature a fine distribution of the F4TCNQ dopant:semiconductor complex. Changes in electrical conductivity from 0.1 to 0.3 S cm−1 and Seebeck coefficient from 100 to 60 μV K−1 upon addition of the insulator correlate with an increase in doping efficiency from 20% to 40% for heavily doped ternary blends. An invariant bulk thermal conductivity of about 0.3 W m−1 K−1 gives rise to a thermoelectric Figure of merit ZT ∼ 10−4 that remains unaltered for an insulator content of more than 60 wt%. Free-standing, mechanically robust tapes illustrate the versatility of the developed dopant:semiconductor:insulator ternary blends.

  17. Interpolymer reactions of nonionic polymers with polyacrylic acid in aqueous solutions

    Directory of Open Access Journals (Sweden)

    E. Shaikhutdinov

    2012-03-01

    Full Text Available Results of fundamental investigations in the intermacromolecular reactions and interpolymer complexes to be performed by authors with co-workes within last 20 years have been intergrated and summarized in the present review. The raw of fundamental regularities in the effect of factors of different nature (pH, ionic strength, temperature, hydrophilic-hydrophobic balance of macrochain, etc. on the complexation of nonionic polymers with polycarboxylic acids in aqueous solutions has been revealed. Critical pH upon complexation (pHcrit. has been used for evaluation of the complexing ability of the polymers. It was shown tha tdepending on pHcrit. all systems can be divided into 2 groups, namely, weak complexing and strongly complexing. The existence of two critical pH upon complexation responsible for formation typical interpolymer complexes and hydrophilic associations has been demonstrated by the method of luminescence spectroscopy.

  18. Rapid adsorption of Pb, Cu and Cd from aqueous solutions by β-cyclodextrin polymers

    Science.gov (United States)

    He, Junyong; Li, Yulian; Wang, Chengming; Zhang, Kaisheng; Lin, Dongyue; Kong, Lingtao; Liu, Jinhuai

    2017-12-01

    Removing heavy metals from aqueous solutions has drawn more and more attentions these years because of their serious global health challenge to human society. To develop an adsorbent with low-cost and high-efficiency for removal of heavy metals (HMs), β-cyclodextrin (β-CD) polymers crosslinked with rigid aromatic groups were prepared and used for lead (Pb), copper (Cu) and cadmium (Cd) removal for the first time. The negatively charged β-CD polymers with large BET surface area were suitable to be used in HMs adsorption. The adsorption process completed in 5 min was well fit by Freundlich isotherm model and pseudo-second-order model. The intraparticle diffusion model was also appropriate to describe the adsorption of Pb, Cu and Cd on β-CD polymer. The maximum of adsorption capacities at 25 °C for Pb, Cu and Cd were 196.42, 164.43 and 136.43 mg/g when the initial concentration was 200 mg/L. The HMs adsorption process on the surface of β-CD polymer was an endothermic and spontaneous process. Both of the electrostatic interaction and distribution of Pb, Cu and Cd species influenced the adsorption process at different pH values. The order of removal efficiencies in multi-component adsorption for the three metal ions were Pb > Cu > Cd. The adsorption mechanisms were H+ ions on hydroxyl groups exchanged with heavy metal ions and electrostatic interactions. This study indicated that β-CD polymers could be developed into effective adsorbents for rapid removal of heavy metals.

  19. Characterization of ethyl cellulose polymer.

    Science.gov (United States)

    Mahnaj, Tazin; Ahmed, Salah U; Plakogiannis, Fotios M

    2013-01-01

    Ethyl cellulose (EC) polymer was characterized for its property before considering the interactions with the plasicizer. Ethocel Std.10 FP Premium from Dow chemical company USA was tested for its solubility, morphology and thermal properties. Seven percentage of EC solution in ethanol was found to be the right viscosity used to prepare the film. The EC polymer and EC film without any plasticizers showed almost identical thermal behavior, but in X-ray diffraction showed different arrangements of crystallites and amorphous region. Dynamic mechanical analysis of film showed that without a plasticizer, EC film was not flexible and had very low elongation with high applied force. The aim of the work was to avoid using the commercially available EC dispersions Surelease® and Aquacoat®; both already have additives on it. Instead, Ethocel EC polymer (powder) was characterized in our laboratory in order to find out the properties of polymer before considering the interactions of the polymer with various plasticizers.

  20. Effect of solution processed and thermally evaporated interlayers on the performance of backgrated polymer solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Jayawardena, K.D.G.I.; Amarasinghe, K.M.P.; Nismy, N.A. [Advanced Technology Institute, Department of Electronic Engineering, University of Surrey, Guildford GU2 7XH (United Kingdom); Mills, C.A. [Advanced Technology Institute, Department of Electronic Engineering, University of Surrey, Guildford GU2 7XH (United Kingdom); Advanced Coatings Group, Surface Engineering Department, Tata Steel Research Development and Technology, Swinden Technology Centre, Rotherham, S60 3AR (United Kingdom); Silva, S.R.P., E-mail: s.silva@surrey.ac.uk [Advanced Technology Institute, Department of Electronic Engineering, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2015-09-30

    Polymer solar cells are fast gaining momentum as a potential solution towards low cost sustainable energy generation. However, the performance of architectures is known to be limited by the thin film nature of the active layer which, although required due to low charge carrier mobilities, limits the optical coupling to the active layer. The formation of periodic backgratings has been proposed as a solution to this problem. Here, we investigate the effect of solution processed and thermally evaporated interlayers on the performance of backgrated polymer solar cells. Analysis of device performance under standard conditions indicates higher power conversion efficiencies with the incorporation of the evaporated interlayer (5.7%) over a sol–gel processed interlayer (4.9%). This is driven by a more conformal coating as evidenced through two orders of magnitude higher electron mobilities (10{sup −5} versus 10{sup −7} cm{sup 2} V{sup −1} s{sup −1}) as well as the balanced electron and hole transport observed for the former architecture. It is believed that these results will catalyse further development of such device engineering concepts for improved optical coupling in thin film photovoltaics. - Highlights: • Effect of interlayers on backgrated photovoltaic devices is tested. • Evaporated interlayers lead to better device performance. • Better charge extraction is observed for evaporated interlayers.

  1. Gold nanorod linking to control plasmonic properties in solution and polymer nanocomposites.

    Science.gov (United States)

    Ferrier, Robert C; Lee, Hyun-Su; Hore, Michael J A; Caporizzo, Matthew; Eckmann, David M; Composto, Russell J

    2014-02-25

    A novel, solution-based method is presented to prepare bifunctional gold nanorods (B-NRs), assemble B-NRs end-to-end in various solvents, and disperse linked B-NRs in a polymer matrix. The B-NRs have poly(ethylene glycol) grafted along its long axis and cysteine adsorbed to its ends. By controlling cysteine coverage, bifunctional ligands or polymer can be end-grafted to the AuNRs. Here, two dithiol ligands (C6DT and C9DT) are used to link the B-NRs in organic solvents. With increasing incubation time, the nanorod chain length increases linearly as the longitudinal surface plasmon resonance shifts toward lower adsorption wavelengths (i.e., red shift). Analogous to step-growth polymerization, the polydispersity in chain length also increases. Upon adding poly(ethylene glycol) or poly(methyl methacrylate) to chloroform solution with linked B-NR, the nanorod chains are shown to retain end-to-end linking upon spin-casting into PEO or PMMA films. Using quartz crystal microbalance with dissipation (QCM-D), the mechanism of nanorod linking is investigated on planar gold surfaces. At submonolayer coverage of cysteine, C6DT molecules can insert between cysteines and reach an areal density of 3.4 molecules per nm(2). To mimic the linking of Au NRs, this planar surface is exposed to cysteine-coated Au nanoparticles, which graft at 7 NPs per μm(2). This solution-based method to prepare, assemble, and disperse Au nanorods is applicable to other nanorod systems (e.g., CdSe) and presents a new strategy to assemble anisotropic particles in organic solvents and polymer coatings.

  2. Communication: Relationship between solute localization and diffusion in a dynamically constrained polymer system

    Energy Technology Data Exchange (ETDEWEB)

    Saylor, David M.; Jawahery, Sudi; Silverstein, Joshua S.; Forrey, Christopher [Center for Devices and Radiological Health, FDA, Silver Spring, Maryland 20993 (United States)

    2016-07-21

    We investigate the link between dynamic localization, characterized by the Debye–Waller factor, 〈u{sup 2}〉, and solute self-diffusivity, D, in a polymer system using atomistic molecular dynamics simulations and vapor sorption experiments. We find a linear relationship between lnD and 1/〈u{sup 2}〉 over more than four decades of D, encompassing most of the glass formation regime. The observed linearity is consistent with the Langevin dynamics in a periodically varying potential field and may offer a means to rapidly assess diffusion based on the characterization of dynamic localization.

  3. Dynamic proton polarisation on polymers in solution: creating contrast in neutron scattering

    International Nuclear Information System (INIS)

    Grinten, M.G.D. van der

    1995-01-01

    Dynamic nuclear polarisation (DNP) as an alternative or additional method to create contrast in neutron small angle scattering has been investigated with emphasis on the study of polymers in solution. The need for high polarisations imposes specific requirements on the sample and its environment. Vitreous beads have been used as samples. Nuclear relaxation times show that they contain dissolved air. Parasitic scattering from the solvent is observed, probably arising from nanometer air bubbles. DNP is shown to be useful, in particular for samples that consist of mixtures of hydrogen-free and hydrogen-rich molecules, where the different molecules can be highlighted by changing the polarisation. ((orig.))

  4. Utilization of carbon dioxide for polymer electrolytes [I]: Effect of supercritical treatment conditions on ionic conduction in amorphous polyether/salt mixtures

    International Nuclear Information System (INIS)

    Oe, Yoshiyuki; Tominaga, Yoichi

    2011-01-01

    Highlights: ► Supercritical CO 2 treatment on amorphous polyether/salt mixtures improves ionic conductivity in the dry state. ► Suitable CO 2 condition for high conductivity exists in near the critical temperature and pressure. ► Conductivity decreases only 20% after 30 days. ► Dissociation of free ClO 4 − and interactions between ether chains and Li + increase in treated electrolytes. - Abstract: Supercritical carbon dioxide (scCO 2 ) as a treatment medium has a possibility to realize excellent room temperature conductivity more than 10 −4 S/cm for polymer electrolytes in the dry state. In this study, a typical high ion-conductive polyether-based electrolyte which consists of poly-[ethylene oxide-co-2-(2-methoxyethoxy)ethyl glycidyl ether] (P(EO/EM)) and lithium perchlorate (LiClO 4 ) was used as a model sample for the scCO 2 treatment. We found the suitable scCO 2 treatment conditions (pressure, temperature and time) for high conductivity. The conductivity of sample treated at 7.5 MPa and 40 °C for 40 min was more than 100-times higher than that of original without the treatment, and the value decreased only 20% after 30 days. DSC measurement revealed that the decrease in glass transition temperature (T g ) is caused by the scCO 2 -treatment. The change of ionic association in the scCO 2 -treated samples was confirmed using FT-IR measurement. The scCO 2 treatment gave rise to increase in peak fraction of free ClO 4 − anions (620–625 cm −1 ) and peak shift of ν(C–O–C) mode to lower frequency region (1060–1070 cm −1 ) depending on ether–Li + interactions.

  5. Photogeneration of H2O2 in SPEEK/PVA aqueous polymer solutions.

    Science.gov (United States)

    Little, Brian K; Lockhart, PaviElle; Slaten, B L; Mills, G

    2013-05-23

    Photolysis of air-saturated aqueous solutions containing sulphonated poly(ether etherketone) and poly(vinyl alcohol) results in the generation of hydrogen peroxide. Consumption of oxygen and H2O2 formation are initially concurrent processes with a quantum yield of peroxide generation of 0.02 in stirred or unstirred solutions within the range of 7 ≤ pH ≤ 9. The results are rationalized in terms of O2 reduction by photogenerated α-hydroxy radicals of the polymeric ketone in competition with radical-radical processes that consume the macromolecular reducing agents. Generation of H2O2 is controlled by the photochemical transformation that produces the polymer radicals, which is most efficient in neutral and slightly alkaline solutions. Quenching of the excited state of the polyketone by both H3O(+) and OH(-) affect the yields of the reducing macromolecular radicals and of H2O2. Deprotonation of the α-hydroxy polymeric radicals at pH > 9 accelerate their decay and contribute to suppressing the peroxide yields in basic solutions. Maxima in [H2O2] are observed when illuminations are performed with static systems, where O2 reduction is faster than diffusion of oxygen into the solutions. Under such conditions H2O2 can compete with O2 for the reducing radicals resulting in a consumption of the peroxide.

  6. Enhanced removal of humic acid from aqueous solution by novel stabilized nano-amorphous calcium phosphate: Behaviors and mechanisms

    Science.gov (United States)

    Jiang, Ling; Li, Yiming; Shao, Yi; Zhang, Yong; Han, Ruiming; Li, Shiyin; Wei, Wei

    2018-01-01

    Stabilized nano-amorphous calcium phosphate (nACP) was prepared using polyethylene glycol as stabilizer to obtain a nanosized amorphous adsorbent. The produced nACP was evaluated by using XRD, FTIR, SEM and X-ray photoelectron spectroscopy (XPS). The sedimentation test demonstrated that nACP exhibited better stability than crystallized hydroxyapatite. The adsorption efficiency of the nACP material for aqueous humic acid (HA) was evaluated from the point of view of medium pH, adsorption time, temperature, and ionic strength, as well as the presences of metal ions. The results of the study showed very good adsorption performance towards aqueous HA. The Sips modeling results revealed that the stabilized nACP adsorbent had a considerably high adsorption capacity (248.3 mg/g) for HA at 298 K. The adsorption data fitted well into pseudo-second order and Elovich kinetic models. XPS analyses indicated that HA retention on nACP material might be due to the surface complexation reaction between oxygen-containing group and calcium of HA and nACP, respectively. Moreover, the HA adsorption capacity of nACP could still keep more than 86% after four adsorption-desorption cycles. By taking into account all results it was concluded that the nACP adsorbent leveraged its stability in combination with its high uptake capacity to offer a great promise for HA adsorption from water.

  7. Solution-Mediated Annealing of Polymer Optical Fiber Bragg Gratings at Room Temperature

    DEFF Research Database (Denmark)

    Fasano, Andrea; Woyessa, Getinet; Janting, Jakob

    2017-01-01

    In this letter, we investigate the response of poly(methylmethacrylate) (PMMA) microstructured polymer optical fiber Bragg gratings (POFBGs) after immersion inmethanol/water solutions at room temperature. As the glass transition temperature of solution-equilibrated PMMA differs from the one...... of solvent-free PMMA, different concentrations of methanol and water lead to various degrees of frozen-in stress relaxation in the fiber. After solvent evaporation, we observe a permanent blue-shift in the grating resonance wavelength. The main contribution in the resonance wavelength shift arises from...... a permanent change in the size of the fiber. The results are compared with conventional annealing. The proposed methodology is cost-effective as it does not require a climate chamber. Furthermore, it enables an easy-to-control tuning of the resonance wavelength of POFBGs....

  8. Chemical solution deposition of YBCO thin film by different polymer additives

    International Nuclear Information System (INIS)

    Wang, W.T.; Li, G.; Pu, M.H.; Sun, R.P.; Zhou, H.M.; Zhang, Y.; Zhang, H.; Yang, Y.; Cheng, C.H.; Zhao, Y.

    2008-01-01

    A polymer-assisted chemical solution deposition approach has been proposed for the preparation of YBCO thin film. Different additives like PVB (polyvinyl butyral), PEG (polyethylene glycol) and PVP (polyvinylpyrrolidone) have been used to adjust the final viscosity of the precursor solution and thus the film formation. In this fluorine-free approach, YBCO has been deposited on single crystal substrates with metal acetates being starting materials. Biaxially textured YBCO thin films have been obtained. However, different additives lead to different microstructure. Dense, smooth and crack-free YBCO film prepared with PVB as additive yields sharp superconducting transition around T c = 90 K as well as high J c (0 T, 77 K) over 3 MA/cm 2

  9. Solution-processed parallel tandem polymer solar cells using silver nanowires as intermediate electrode.

    Science.gov (United States)

    Guo, Fei; Kubis, Peter; Li, Ning; Przybilla, Thomas; Matt, Gebhard; Stubhan, Tobias; Ameri, Tayebeh; Butz, Benjamin; Spiecker, Erdmann; Forberich, Karen; Brabec, Christoph J

    2014-12-23

    Tandem architecture is the most relevant concept to overcome the efficiency limit of single-junction photovoltaic solar cells. Series-connected tandem polymer solar cells (PSCs) have advanced rapidly during the past decade. In contrast, the development of parallel-connected tandem cells is lagging far behind due to the big challenge in establishing an efficient interlayer with high transparency and high in-plane conductivity. Here, we report all-solution fabrication of parallel tandem PSCs using silver nanowires as intermediate charge collecting electrode. Through a rational interface design, a robust interlayer is established, enabling the efficient extraction and transport of electrons from subcells. The resulting parallel tandem cells exhibit high fill factors of ∼60% and enhanced current densities which are identical to the sum of the current densities of the subcells. These results suggest that solution-processed parallel tandem configuration provides an alternative avenue toward high performance photovoltaic devices.

  10. Chemical solution deposition of YBCO thin film by different polymer additives

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W.T.; Li, G.; Pu, M.H.; Sun, R.P.; Zhou, H.M.; Zhang, Y. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu 610031 (China); Zhang, H. [Department of Physics, Peking University, Beijing 100871 (China); Yang, Y. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu 610031 (China); Cheng, C.H. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu 610031 (China); School of Materials Science and Engineering, University of New South Wale, Sydney, 2052 NSW (Australia); Zhao, Y. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu 610031 (China); School of Materials Science and Engineering, University of New South Wale, Sydney, 2052 NSW (Australia)], E-mail: yzhao@swjtu.edu.cn

    2008-09-15

    A polymer-assisted chemical solution deposition approach has been proposed for the preparation of YBCO thin film. Different additives like PVB (polyvinyl butyral), PEG (polyethylene glycol) and PVP (polyvinylpyrrolidone) have been used to adjust the final viscosity of the precursor solution and thus the film formation. In this fluorine-free approach, YBCO has been deposited on single crystal substrates with metal acetates being starting materials. Biaxially textured YBCO thin films have been obtained. However, different additives lead to different microstructure. Dense, smooth and crack-free YBCO film prepared with PVB as additive yields sharp superconducting transition around T{sub c} = 90 K as well as high J{sub c} (0 T, 77 K) over 3 MA/cm{sup 2}.

  11. EXTRACTION AND SORPTION BENZOIC ACID FROM AQUEOUS SOLUTIONS OF POLYMERS BASED ON N-VINYLAMIDES

    Directory of Open Access Journals (Sweden)

    A. G. Savvina

    2015-01-01

    Full Text Available The widespread use of aromatic acids (benzoic acid, salicylic as preservatives necessitates their qualitative and quantitative determination in food. Effective and common way to separation and concentration of aromatic acids liquid extraction. Biphasic system of water-soluble polymers based on (poly-N-vinyl pyrrolidone, and poly-N-vinylcaprolactam satisfy the requirements of the extraction system. When sorption concentration improved definition of the metrological characteristics, comply with the requirements for sensitivity and selectivity definition appears possible, use of inexpensive and readily available analytical equipment. When studying the adsorption of benzoic acid used as a sorbent crosslinked polymer based on N-vinyl pyrrolidone, obtained by radical polymerisation of a functional monomer and crosslinker. In the extraction of benzoic acid to maximize the allocation of water and the organic phase of the polymer used salt solutions with concentrations close to saturation. Regardless of the nature of the anion salt is used as salting-out agent, aromatic acids sorption increases with the size of the cations. In the experiment the maximum recovery rate (80% benzoic acid obtained in the PVP (0.2 weight%. Ammonium sulphate. The dependence stepepni benzoic acid extraction from time sorption sorbent mass and the pH of the aqueous phase. To establish equilibrium in the system, for 20 minutes. The dependence of the degree of extraction of the acid pH indicates that the acid is extracted into the molecular form. The maximum adsorption is reached at pH 3,5, with its efficiency decreases symbatically reduce the amount of undissociated acid molecules in solution.

  12. On the role of specific interactions in the diffusion of nanoparticles in aqueous polymer solutions.

    Science.gov (United States)

    Mun, Ellina A; Hannell, Claire; Rogers, Sarah E; Hole, Patrick; Williams, Adrian C; Khutoryanskiy, Vitaliy V

    2014-01-14

    Understanding nanoparticle diffusion within non-Newtonian biological and synthetic fluids is essential in designing novel formulations (e.g., nanomedicines for drug delivery, shampoos, lotions, coatings, paints, etc.), but is presently poorly defined. This study reports the diffusion of thiolated and PEGylated silica nanoparticles, characterized by small-angle neutron scattering, in solutions of various water-soluble polymers such as poly(acrylic acid) (PAA), poly(N-vinylpyrrolidone) (PVP), poly(ethylene oxide) (PEO), and hydroxyethylcellulose (HEC) probed using NanoSight nanoparticle tracking analysis. Results show that the diffusivity of nanoparticles is affected by their dimensions, medium viscosity, and, in particular, the specific interactions between nanoparticles and the macromolecules in solution; strong attractive interactions such as hydrogen bonding hamper diffusion. The water-soluble polymers retarded the diffusion of thiolated particles in the order PEO > PVP > PAA > HEC whereas for PEGylated silica particles retardation followed the order PAA > PVP = HEC > PEO. In the absence of specific interactions with the medium, PEGylated nanoparticles exhibit enhanced mobility compared to their thiolated counterparts despite some increase in their dimensions.

  13. Recent Advances in Characterization of Lignin Polymer by Solution-State Nuclear Magnetic Resonance (NMR Methodology

    Directory of Open Access Journals (Sweden)

    Run-Cang Sun

    2013-01-01

    Full Text Available The demand for efficient utilization of biomass induces a detailed analysis of the fundamental chemical structures of biomass, especially the complex structures of lignin polymers, which have long been recognized for their negative impact on biorefinery. Traditionally, it has been attempted to reveal the complicated and heterogeneous structure of lignin by a series of chemical analyses, such as thioacidolysis (TA, nitrobenzene oxidation (NBO, and derivatization followed by reductive cleavage (DFRC. Recent advances in nuclear magnetic resonance (NMR technology undoubtedly have made solution-state NMR become the most widely used technique in structural characterization of lignin due to its versatility in illustrating structural features and structural transformations of lignin polymers. As one of the most promising diagnostic tools, NMR provides unambiguous evidence for specific structures as well as quantitative structural information. The recent advances in two-dimensional solution-state NMR techniques for structural analysis of lignin in isolated and whole cell wall states (in situ, as well as their applications are reviewed.

  14. Neutron spin echo spectroscopy. Its application to the study of the dynamics of polymers in solution

    International Nuclear Information System (INIS)

    Papoular, Robert

    1992-06-01

    This work focuses on Neutron Spin Echo (NSE) spectroscopy and on the NSE spectrometer MESS, which we have built at the L.L.B. (CE Saclay). After analyzing in detail the classical and quantum principles of this type of instrument, and illustrated them with optical analogies, we expound a simple formalism for the interpretation of polarized neutron experiments of the most general type. In a second part, we describe the MESS spectrometer extensively; its characteristics and performances as well as the first results obtained with this instrument. In particular, we include two papers showing how the neutron depolarization, spin rotation and echoes can be used to investigate high-Tc superconductors. The last part deals with the dynamics of Polymer-Polymer-Solvent ternary solutions and demonstrates how the Neutron Spin Echo technique becomes a privileged tool for such physico-chemical studies thanks to the joint use of NSE and contrast variation methods, coupled with the adequate ranges of time and scattering vectors accessible. Finally, we describe the specific case of partially deuterated polydimethyl-siloxane (PDMS) in semi-dilute solution in Toluene. We have experimentally and separately evidenced the cooperative and inter-diffusive diffusion modes predicted by the theory of Akcasu, Benoit, Benmouna et al. These results, obtained at the L.L.B. (CE Saclay) are the subject matter of the last paper included in this work. (author) [fr

  15. Fully solution-processing route toward highly transparent polymer solar cells.

    Science.gov (United States)

    Guo, Fei; Kubis, Peter; Stubhan, Tobias; Li, Ning; Baran, Derya; Przybilla, Thomas; Spiecker, Erdmann; Forberich, Karen; Brabec, Christoph J

    2014-10-22

    We report highly transparent polymer solar cells using metallic silver nanowires (AgNWs) as both the electron- and hole-collecting electrodes. The entire stack of the devices is processed from solution using a doctor blading technique. A thin layer of zinc oxide nanoparticles is introduced between photoactive layer and top AgNW electrode which plays decisive roles in device functionality: it serves as a mechanical foundation which allows the solution-deposition of top AgNWs, and more importantly it facilitates charge carriers extraction due to the better energy level alignment and the formation of ohmic contacts between the active layer/ZnO and ZnO/AgNWs. The resulting semitransparent polymer:fullerene solar cells showed a power conversion efficiency of 2.9%, which is 72% of the efficiency of an opaque reference device. Moreover, an average transmittance of 41% in the wavelength range of 400-800 nm is achieved, which is of particular interest for applications in transparent architectures.

  16. Ambipolar Small-Molecule:Polymer Blend Semiconductors for Solution-Processable Organic Field-Effect Transistors.

    Science.gov (United States)

    Kang, Minji; Hwang, Hansu; Park, Won-Tae; Khim, Dongyoon; Yeo, Jun-Seok; Kim, Yunseul; Kim, Yeon-Ju; Noh, Yong-Young; Kim, Dong-Yu

    2017-01-25

    We report on the fabrication of an organic thin-film semiconductor formed using a blend solution of soluble ambipolar small molecules and an insulating polymer binder that exhibits vertical phase separation and uniform film formation. The semiconductor thin films are produced in a single step from a mixture containing a small molecular semiconductor, namely, quinoidal biselenophene (QBS), and a binder polymer, namely, poly(2-vinylnaphthalene) (PVN). Organic field-effect transistors (OFETs) based on QBS/PVN blend semiconductor are then assembled using top-gate/bottom-contact device configuration, which achieve almost four times higher mobility than the neat QBS semiconductor. Depth profile via secondary ion mass spectrometry and atomic force microscopy images indicate that the QBS domains in the films made from the blend are evenly distributed with a smooth morphology at the bottom of the PVN layer. Bias stress test and variable-temperature measurements on QBS-based OFETs reveal that the QBS/PVN blend semiconductor remarkably reduces the number of trap sites at the gate dielectric/semiconductor interface and the activation energy in the transistor channel. This work provides a one-step solution processing technique, which makes use of soluble ambipolar small molecules to form a thin-film semiconductor for application in high-performance OFETs.

  17. Controlling solution-phase polymer aggregation with molecular weight and solvent additives to optimize polymer-fullerene bulk heterojunction solar cells

    KAUST Repository

    Bartelt, Jonathan A.

    2014-03-20

    The bulk heterojunction (BHJ) solar cell performance of many polymers depends on the polymer molecular weight (M n) and the solvent additive(s) used for solution processing. However, the mechanism that causes these dependencies is not well understood. This work determines how M n and solvent additives affect the performance of BHJ solar cells made with the polymer poly(di(2-ethylhexyloxy)benzo[1,2-b:4,5-b\\']dithiophene-co- octylthieno[3,4-c]pyrrole-4,6-dione) (PBDTTPD). Low M n PBDTTPD devices have exceedingly large fullerene-rich domains, which cause extensive charge-carrier recombination. Increasing the M n of PBDTTPD decreases the size of these domains and significantly improves device performance. PBDTTPD aggregation in solution affects the size of the fullerene-rich domains and this effect is linked to the dependency of PBDTTPD solubility on M n. Due to its poor solubility high M n PBDTTPD quickly forms a fibrillar polymer network during spin-casting and this network acts as a template that prevents large-scale phase separation. Furthermore, processing low M n PBDTTPD devices with a solvent additive improves device performance by inducing polymer aggregation in solution and preventing large fullerene-rich domains from forming. These findings highlight that polymer aggregation in solution plays a significant role in determining the morphology and performance of BHJ solar cells. The performance of poly(di(2-ethylhexyloxy) benzo[1,2-b:4,5-b\\']dithiophene-co-octylthieno[3,4-c]pyrrole-4,6-dione) (PBDTTPD) bulk heterojunction solar cells strongly depends on the polymer molecular weight, and processing these bulk heterojunctions with a solvent additive preferentially improves the performance of low molecular weight devices. It is demonstrated that polymer aggregation in solution significantly impacts the thin-film bulk heterojunction morphology and is vital for high device performance. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. A Mathematical Model of Repeated Impregnation of Porous Bodies with Solutions of Polymers

    Directory of Open Access Journals (Sweden)

    I. V. Glebov

    2015-01-01

    Full Text Available The paper describes basic methods of impregnating porous bodies with solutions of polymers and their use to manufacture prepregs. It also describes the existing methods of manufacturing multilayer prepregs to produce aerospace coating of the spacecraft "Soyuz". It is shown that these prepregs have to meet high requirements for the content of the polymer, as compared with other composite materials, about 35 - 40% of the mass. Methods used for their manufacturing are long-term and non-controllable. The assumption is made that using the vacuum impregnation technology of a woven material will allow to accelerate the manufacturing process of these prepregs and improve their quality.In reviewing the technical literature have been found works on modeling the processes of impregnation, but they are aimed only at studying the speed of the woven material impregnation by various fluids and determining the time of impregnation. There were no models found to define prepreg parameters during the process of multiple impregnations. The aim of this work is to develop the simple mathematical model, which enables us to predict the polymer content of volatile products in the prepreg after each cycle of multiple impregnation of woven material with a solution of the polymer.To consider the vacuum impregnation method are used the prepregs based on silica and silica-nylon stitch-bonding fabric and bakelite varnish LBS-4 containing 50 - 60% of phenol resin and the solvent with minor impurities of pure phenol and water, as an example. To describe the process of vacuum impregnation of the porous work-piece is developed a mathematical description of the process of filling the porous space of the material with a varnish. It is assumed that the varnish components fill the porous space of the material in the same proportion as they are contained in the varnish.It is shown that a single impregnation cannot ensure the content of phenol resin in the prepreg over 32%, which does

  19. Interaction of derived polymers from pyrrole with biocompatible solutions; Interaccion de polimeros derivados de pirrol con soluciones biocompatibles

    Energy Technology Data Exchange (ETDEWEB)

    Lopez G, O. G.

    2010-07-01

    This work presents a study about the synthesis by plasma, the electric properties and superficial interaction of polymers derived from pyrrole doped with Iodine with potential use as bio material. Poly-pyrrole is a semiconductor and biocompatible polymer with potential application in the development of artificial muscles and implants where the electric interaction between cells and material is an important variable. The syntheses were made at 13.5 MHz in a glass tubular reactor of 1500 cm{sup 3} with electrodes of 6.5 cm diameter and stainless steel flanges. An electrode was connected to the RF terminal of the power supply that is combined with a matching coupling resistance. The monomer and dopant used in this work were pyrrole and Iodine respectively, in closed containers. They were vaporized and injected separately into the reactor at room temperature and 0.1 mbar. The vapors of the reagents mixed freely in the reactor. The synthesis time was 240 min at 40, 60, 80 and 100 W. The polymers were obtained as thin films adhered to the reactor walls. The films were washed and swollen with distilled water and removed from the reactor walls with a small spatula. The polymers were irradiated with gamma rays at 18 and 22 KGy. Due to the fact that the doses are cumulative, the final dose applied was 40 KGy. The polymers characterization was carried out by Fourier Transform Infrared Spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy, contact angle, electrical conductivity and X-ray diffraction. The analyses indicates that the polymers have very similar structure in almost the entire power range, showing C-O, C=C, C-H, O-H, N-H bonds with a predominantly amorphous structure. The TGA analyses showed that the material has 4 or 5 loses of material. The first one starts after that 115 C except for the material irradiated at 40 KGy, this one begins in 87 C, the second one is in the interval of 196 and 295 C, the third one between 311 and 500 C, and the

  20. The exact solution of a three-dimensional lattice polymer confined in a slab with sticky walls

    Energy Technology Data Exchange (ETDEWEB)

    Brak, R; Iliev, G K; Owczarek, A L [Department of Mathematics and Statistics, University of Melbourne, Parkville, Vic 3010 (Australia); Whittington, S G [Department of Chemistry, University of Toronto, Toronto M5S 3H6 (Canada)

    2010-04-02

    We present the exact solution of a three-dimensional lattice model of a polymer confined between two sticky walls, that is within a slab. We demonstrate that the model behaves in a similar way to its two-dimensional analogues and agrees with Monte Carlo evidence based upon simulations of self-avoiding walks in slabs. The model on which we focus is a variant of the partially directed walk model on the cubic lattice. We consider both the phase diagram of relatively long polymers in a macroscopic slab and the effective force of the polymer on the walls of the slab.

  1. Solvent-dependent self-assembly and ordering in slow-drying semi-crystalline conjugated polymer solutions

    KAUST Repository

    Zhao, Kui

    2015-09-07

    The mechanistic understanding of the intrinsic molecular self-assembly of conjugated polymers is of immense importance to controlling the microstructure development in organic semiconducting thin films, with meaningful impact on charge transport and optoelectronic properties. Yet, to date the vast majority of studies have focused on the fast solution process itself, with studies of slower intrinsic molecular self-assembly in formulations lagging behind. Here we have investigated molecular self-assembly during spontaneous organization and uncovered how changes in formulation influence the microstructure, morphology and transport properties of conjugated polymer thin films. Our results suggest that the polymer-solvent interaction is the key factor for the molecular self-assembly and changes in macroscopic charge transport, which is in contrast with most solution processes, such as spin-coating and blade coating, where solvent drying kinetics dominates the aggregation and crystallization processes. Energetically favourable interactions between the polymer and its solvent are shown to cause chain expansion, resulting in a large hydrodynamic volume and few chain entanglements in solution. This provides molecular freedom for self-assembly and is shown to greatly enhance the local and long range order of the polymer, intra-chain backbone planarity and crystallite size. These improvements, in turn, are shown to endow the conjugated polymer with high carrier transport, as demonstrated by organic thin film transistors.

  2. 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.

  3. High-Reynolds-number turbulent-boundary-layer wall-pressure fluctuations with dilute polymer solutions

    Science.gov (United States)

    Elbing, Brian R.; Winkel, Eric S.; Ceccio, Steven L.; Perlin, Marc; Dowling, David R.

    2010-08-01

    Wall-pressure fluctuations were investigated within a high-Reynolds-number turbulent boundary layer (TBL) modified by the addition of dilute friction-drag-reducing polymer solutions. The experiment was conducted at the U.S. Navy's Large Cavitation Channel on a 12.9 m long flat-plate test model with the surface hydraulically smooth (k+<0.2) and achieving downstream-distance-based Reynolds numbers to 220×106. The polymer (polyethylene oxide) solution was injected into the TBL through a slot in the surface. The primary flow diagnostics were skin-friction drag balances and an array of flush-mounted dynamic pressure transducers 9.8 m from the model leading edge. Parameters varied included the free-stream speed (6.7, 13.4, and 20.2 m s-1) and the injection condition (polymer molecular weight, injection concentration, and volumetric injection flux). The behavior of the pressure spectra, convection velocity, and coherence, regardless of the injection condition, were determined primarily based on the level of drag reduction. Results were divided into two regimes dependent on the level of polymer drag reduction (PDR), nominally separated at a PDR of 40%. The low-PDR regime is characterized by decreasing mean-square pressure fluctuations and increasing convection velocity with increasing drag reduction. This shows that the decrease in the pressure spectra with increasing drag reduction is due in part to the moving of the turbulent structures from the wall. Conversely, with further increases in drag reduction, the high-PDR regime has negligible variation in the mean-squared pressure fluctuations and convection velocity. The convection velocity remains constant at approximately 10% above the baseline-flow convection velocity, which suggests that the turbulent structures no longer move farther from the wall with increasing drag reduction. In light of recent numerical work, the coherence results indicate that in the low-PDR regime, the turbulent structures are being elongated in

  4. Self-Assembled CNT-Polymer Hybrids in Single-Walled Carbon Nanotubes Dispersed Aqueous Triblock Copolymer Solutions

    Science.gov (United States)

    Vijayaraghavan, D.; Manjunatha, A. S.; Poojitha, C. G.

    2018-04-01

    We have carried out scanning electron microscopy (SEM), differential scanning calorimetry (DSC), small angle X-ray scattering (SAXS), electrical conductivity, and 1H NMR studies as a function of temperature on single-walled carbon nanotubes (SWCNTs) dispersed aqueous triblock copolymer (P123) solutions. The single-walled carbon nanotubes in this system aggregate to form bundles, and the bundles aggregate to form net-like structures. Depending on the temperature and phases of the polymer, this system exhibits three different self-assembled CNT-polymer hybrids. We find CNT-unimer hybrid at low temperatures, CNT-micelle hybrid at intermediate temperatures wherein the polymer micelles are adsorbed in the pores of the CNT nets, and another type of CNT-micelle hybrid at high temperatures wherein the polymer micelles are adsorbed on the surface of the CNT bundles. Our DSC thermogram showed two peaks related to these structural changes in the CNT-polymer hybrids. Temperature dependence of the 1H NMR chemical shifts of the molecular groups of the polymer and the AC electrical conductivity of the composite also showed discontinuous changes at the temperatures at which the CNT-polymer hybrid's structural changes are seen. Interestingly, for a higher CNT concentration (0.5 wt.%) in the system, the aggregated polymer micelles adsorbed on the CNTs exhibit cone-like and cube-like morphologies at the intermediate and at high temperatures respectively.

  5. A new algorithm for DNS of turbulent polymer solutions using the FENE-P model

    Science.gov (United States)

    Vaithianathan, T.; Collins, Lance; Robert, Ashish; Brasseur, James

    2004-11-01

    Direct numerical simulations (DNS) of polymer solutions based on the finite extensible nonlinear elastic model with the Peterlin closure (FENE-P) solve for a conformation tensor with properties that must be maintained by the numerical algorithm. In particular, the eigenvalues of the tensor are all positive (to maintain positive definiteness) and the sum is bounded by the maximum extension length. Loss of either of these properties will give rise to unphysical instabilities. In earlier work, Vaithianathan & Collins (2003) devised an algorithm based on an eigendecomposition that allows you to update the eigenvalues of the conformation tensor directly, making it easier to maintain the necessary conditions for a stable calculation. However, simple fixes (such as ceilings and floors) yield results that violate overall conservation. The present finite-difference algorithm is inherently designed to satisfy all of the bounds on the eigenvalues, and thus restores overall conservation. New results suggest that the earlier algorithm may have exaggerated the energy exchange at high wavenumbers. In particular, feedback of the polymer elastic energy to the isotropic turbulence is now greatly reduced.

  6. Efficiency of solution-processed multilayer polymer light-emitting diodes using charge blocking layers

    Science.gov (United States)

    Kasparek, Christian; Rörich, Irina; Blom, Paul W. M.; Wetzelaer, Gert-Jan A. H.

    2018-01-01

    By blending semiconducting polymers with the cross-linkable matrix ethoxylated-(4)-bisphenol-a-dimethacrylate (SR540), an insoluble layer is acquired after UV-illumination. Following this approach, a trilayer polymer light-emitting diode (PLED) consisting of a blend of poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine] (poly-TPD) and SR540 as an electron-blocking layer, Super Yellow-Poly(p-phenylene vinylene) (SY-PPV) blended with SR540 as an emissive layer, and poly(9,9-di-n-octylfluorenyl-2,7-diyl) as a hole-blocking layer is fabricated from solution. The trilayer PLED shows a 23% increase in efficiency at low voltage as compared to a single layer SY-PPV PLED. However, at higher voltage, the advantage in current efficiency gradually decreases. A combined experimental and modelling study shows that the increased efficiency is not only due to the elimination of exciton quenching at the electrodes but also due to suppressed nonradiative trap-assisted recombination due to carrier confinement. At high voltages, holes can overcome the hole-blocking barrier, which explains the efficiency roll-off.

  7. Removal of anionic azo dyes from aqueous solution by functional ionic liquid cross-linked polymer

    International Nuclear Information System (INIS)

    Gao, Hejun; Kan, Taotao; Zhao, Siyuan; Qian, Yixia; Cheng, Xiyuan; Wu, Wenli; Wang, Xiaodong; Zheng, Liqiang

    2013-01-01

    Highlights: • Equilibrium, kinetic and thermodynamic of adsorption of dyes onto PDVB-IL was investigated. • PDVB-IL has a high adsorption capacity to treat dyes solution. • Higher adsorption capacity is due to the functional groups of PDVB-IL. • Molecular structure of dyes influences the adsorption capacity. -- Abstract: A novel functional ionic liquid based cross-linked polymer (PDVB-IL) was synthesized from 1-aminoethyl-3-vinylimidazolium chloride and divinylbenzene for use as an adsorbent. The physicochemical properties of PDVB-IL were investigated by Fourier transform infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis. The adsorptive capacity was investigated using anionic azo dyes of orange II, sunset yellow FCF, and amaranth as adsorbates. The maximum adsorption capacity could reach 925.09, 734.62, and 547.17 mg/g for orange II, sunset yellow FCF and amaranth at 25 °C, respectively, which are much better than most of the other adsorbents reported earlier. The effect of pH value was investigated in the range of 1–8. The result shows that a low pH value is found to favor the adsorption of those anionic azo dyes. The adsorption kinetics and isotherms are well fitted by a pseudo second-order model and Langmuir model, respectively. The adsorption process is found to be dominated by physisorption. The introduction of functional ionic liquid moieties into cross-linked poly(divinylbenzene) polymer constitutes a new and efficient kind of adsorbent

  8. Amorphous nanophotonics

    CERN Document Server

    Scharf, Toralf

    2013-01-01

    This book represents the first comprehensive overview over amorphous nano-optical and nano-photonic systems. Nanophotonics is a burgeoning branch of optics that enables many applications by steering the mould of light on length scales smaller than the wavelength with devoted nanostructures. Amorphous nanophotonics exploits self-organization mechanisms based on bottom-up approaches to fabricate nanooptical systems. The resulting structures presented in the book are characterized by a deterministic unit cell with tailored geometries; but their spatial arrangement is not controlled. Instead of periodic, the structures appear either amorphous or random. The aim of this book is to discuss all aspects related to observable effects in amorphous nanophotonic material and aspects related to their design, fabrication, characterization and integration into applications. The book has an interdisciplinary nature with contributions from scientists in physics, chemistry and materials sciences and sheds light on the topic fr...

  9. An In Vitro Study on the Effect of Amorphous Calcium Phosphate and Fluoride Solutions on Color Improvement of White Spot Lesions

    Directory of Open Access Journals (Sweden)

    Fahimeh Farzanegan

    2018-06-01

    Full Text Available The ability of remineralizing agents to improve the color of white spot lesions (WSL is an important aspect that should be investigated. The aim of this study was to evaluate the effects of 0.05% amorphous calcium phosphate (ACP, 0.5% ACP, and 0.05% fluoride solutions, as well as artificial saliva on the color improvement of white spot lesions (WSLs. In this in vitro study, 50 human premolar teeth were randomly classified into five groups. At baseline, all the samples were assessed by using a colorimeter (E0. Then, white spot lesions were induced on the surface of the teeth by means of a pH-cycling model, and the colorimeter was used again (E1. Afterwards, samples of the 1st and 2nd groups were kept in 0.05% ACP and 0.5% ACP solutions for 1 min/day, respectively. The 3rd group specimens were placed in 0.05% fluoride solution for 1 min/day. The other two groups were kept in artificial saliva and distilled in water separately. All the samples were assessed by the colorimeter for a third time (E2. We found no significant difference between the groups in ∆E1. There was also no significant difference among 0.05% ACP solution, 0.5% ACP solution, 0.05% fluoride solution, and artificial saliva considering ∆E2. However, a significant difference was noted between the above-mentioned solutions and distilled water in ∆E2. With respect to ∆E3, there were considerable differences between ACP solution and artificial saliva. The same results were obtained for the difference between fluoride solution and artificial saliva. However, no significant difference was found among 0.05% ACP, 0.5% ACP, and 0.05% fluoride solutions in terms of ∆E3. In Conclusion, ACP is as effective as fluoride in the color improvement of WSLs and the recommended treatment for this purpose is daily use of 0.05% ACP, 0.5% ACP or 0.05% fluoride solutions.

  10. Size-exclusion partitioning of neutral solutes in crosslinked polymer networks: A Monte Carlo simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Quesada-Pérez, Manuel; Maroto-Centeno, José Alberto [Departamento de Física, Escuela Politécnica Superior de Linares, Universidad de Jaén, 23700 Linares, Jaén (Spain); Adroher-Benítez, Irene [Grupo de Física de Fluidos y Biocoloides, Departamento de Física Aplicada, Facultad de Ciencias, Universidad de Granada, 18071 Granada (Spain)

    2014-05-28

    In this work, the size-exclusion partitioning of neutral solutes in crosslinked polymer networks has been studied through Monte Carlo simulations. Two models that provide user-friendly expressions to predict the partition coefficient have been tested over a wide range of volume fractions: Ogston's model (especially devised for fibrous media) and the pore model. The effects of crosslinking and bond stiffness have also been analyzed. Our results suggest that the fiber model can acceptably account for size-exclusion effects in crosslinked gels. Its predictions are good for large solutes if the fiber diameter is assumed to be the effective monomer diameter. For solutes sizes comparable to the monomer dimensions, a smaller fiber diameter must be used. Regarding the pore model, the partition coefficient is poorly predicted when the pore diameter is estimated as the distance between adjacent crosslinker molecules. On the other hand, our results prove that the pore sizes obtained from the pore model by fitting partitioning data of swollen gels are overestimated.

  11. DESIGN AND TECHNOLOGICAL SOLUTIONS FOR THE RESTORATION OF SEWERS USING ELEMENTS OF RECYCLED POLYMER COMPOSITE MATERIALS

    Directory of Open Access Journals (Sweden)

    GONCHARENKO D. F.

    2017-01-01

    Full Text Available Problem statement. Currently sanitary drainage systems of large cities in Ukraine are significantly worn down with prolonged use and due to inefficient solutions for protection of the structures from aggressive effects of the environment, poor quality of materials and construction and installation works during building. Restoration of performance characteristics, reliability and durability of sewer tunnels is the costly and technically complex task, which is urgently needed to be fulfilled to prevent accidents including those with serious environmental impact. Modern work technique and the materials used for restoration allow us to solve these problems with different levels of efficiency, while reducing the cost of restoration due to use of recycled polymeric raw material, as well as to improvement of technological solutions is a currently important direction of research. Purpose of the article. To develop solutions for restoring serviceability, reliability and durability of sewer tunnels taking into account the accumulated experience in renovation of water disposal networks. Conclusion. Use of components made of recycled polymer composite materials during restoring sewer tunnels has significant economic and environmental effects and allows to undertake repair work in hard-to-reach areas.

  12. Size-exclusion partitioning of neutral solutes in crosslinked polymer networks: A Monte Carlo simulation study

    International Nuclear Information System (INIS)

    Quesada-Pérez, Manuel; Maroto-Centeno, José Alberto; Adroher-Benítez, Irene

    2014-01-01

    In this work, the size-exclusion partitioning of neutral solutes in crosslinked polymer networks has been studied through Monte Carlo simulations. Two models that provide user-friendly expressions to predict the partition coefficient have been tested over a wide range of volume fractions: Ogston's model (especially devised for fibrous media) and the pore model. The effects of crosslinking and bond stiffness have also been analyzed. Our results suggest that the fiber model can acceptably account for size-exclusion effects in crosslinked gels. Its predictions are good for large solutes if the fiber diameter is assumed to be the effective monomer diameter. For solutes sizes comparable to the monomer dimensions, a smaller fiber diameter must be used. Regarding the pore model, the partition coefficient is poorly predicted when the pore diameter is estimated as the distance between adjacent crosslinker molecules. On the other hand, our results prove that the pore sizes obtained from the pore model by fitting partitioning data of swollen gels are overestimated

  13. Solution processable organic polymers and small molecules for bulk-heterojunction solar cells: A review

    International Nuclear Information System (INIS)

    Sharma, G. D.

    2011-01-01

    Solution processed bulk heterojunction (BHJ) organic solar cells (OSCs) have gained wide interest in past few years and are established as one of the leading next generation photovoltaic technologies for low cost power production. Power conversion efficiencies up to 6% and 6.5% have been reported in the literature for single layer and tandem solar cells, respectively using conjugated polymers. A recent record efficiency about 8.13% with active area of 1.13 cm 2 has been reported. However Solution processable small molecules have been widely applied for photovoltaic (PV) devices in recent years because they show strong absorption properties, and they can be easily purified and deposited onto flexible substrates at low cost. Introducing different donor and acceptor groups to construct donor--acceptor (D--A) structure small molecules has proved to be an efficient way to improve the properties of organic solar cells (OSCs). The power conversion efficiency about 4.4 % has been reported for OSCs based on the small molecules. This review deals with the recent progress of solution processable D--A structure small molecules and discusses the key factors affecting the properties of OSCs based on D--A structure small molecules: sunlight absorption, charge transport and the energy level of the molecules.

  14. A solution-processed binary cathode interfacial layer facilitates electron extraction for inverted polymer solar cells.

    Science.gov (United States)

    Zhang, Xinyuan; Li, Zhiqi; Liu, Chunyu; Guo, Jiaxin; Shen, Liang; Guo, Wenbin

    2018-03-15

    The charge transfer and separation are significantly affected by the electron properties of the interface between the electron-donor layer and the carrier-transporting layer in polymer solar cells (PSCs). In this study, we investigate the electron extraction mechanism of PSCs with a low temperature solution-processed ZnO/PEI as electron transport layer. The incorporation of PEI layer can decrease the work function of ZnO and reduce interfacial barrier, which facilitates electron extraction and suppresses bimolecular recombination, leading to a significant performance enhancement. Furthermore, PEI layer can induce phase separation and passivite inorganic surface trap states as well as shift the interfacial energy offset between metal oxide and organic materials. This work offers a simple and effective way to improve the charge transporting property of organic photovoltaic devices. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Studies on transport phenomena in polymer solutions and suspensions flowing through tubes of tortuous wall geometry

    Science.gov (United States)

    Narayanan, C. M.

    2014-02-01

    Attempts have been made to analyse the momentum and heat transfer characteristics in tortuous flow of non-Newtonian fluids such as suspensions and polymer solutions through tubes of diverging-converging geometry. The results of the study indicate that the transfer coefficients are significantly higher in such systems as compared to the conventional couette flow (through uniform cylindrical tubes). Moreover, the simultaneous increase in pressure drop due to the tortuous wall geometry has been observed to be relatively insignificant. Fluids with different rheological characteristics such as Bingham plastic fluids, pseudoplastic fluids, Ellis model fluids and fluids obeying Reiner-Philippoff rheology have been studied. The specific advantages of these geometries in providing enhanced performance efficiency have been effectively highlighted.

  16. Viscoelasticity and nonlinear simple shear flow behavior of an entangled asymmetric exact comb polymer solution

    KAUST Repository

    Snijkers, F.; Kirkwood, K. M.; Vlassopoulos, D.; Leal, L. G.; Nikopoulou, A.; Hadjichristidis, Nikolaos; Coppola, S.

    2016-01-01

    We report upon the characterization of the steady-state shear stresses and first normal stress differences as a function of shear rate using mechanical rheometry (both with a standard cone and plate and with a cone partitioned plate) and optical rheometry (with a flow-birefringence setup) of an entangled solution of asymmetric exact combs. The combs are polybutadienes (1,4-addition) consisting of an H-skeleton with an additional off-center branch on the backbone. We chose to investigate a solution in order to obtain reliable nonlinear shear data in overlapping dynamic regions with the two different techniques. The transient measurements obtained by cone partitioned plate indicated the appearance of overshoots in both the shear stress and the first normal stress difference during start-up shear flow. Interestingly, the overshoots in the start-up normal stress difference started to occur only at rates above the inverse stretch time of the backbone, when the stretch time of the backbone was estimated in analogy with linear chains including the effects of dynamic dilution of the branches but neglecting the effects of branch point friction, in excellent agreement with the situation for linear polymers. Flow-birefringence measurements were performed in a Couette geometry, and the extracted steady-state shear and first normal stress differences were found to agree well with the mechanical data, but were limited to relatively low rates below the inverse stretch time of the backbone. Finally, the steady-state properties were found to be in good agreement with model predictions based on a nonlinear multimode tube model developed for linear polymers when the branches are treated as solvent.

  17. Viscoelasticity and nonlinear simple shear flow behavior of an entangled asymmetric exact comb polymer solution

    KAUST Repository

    Snijkers, F.

    2016-03-31

    We report upon the characterization of the steady-state shear stresses and first normal stress differences as a function of shear rate using mechanical rheometry (both with a standard cone and plate and with a cone partitioned plate) and optical rheometry (with a flow-birefringence setup) of an entangled solution of asymmetric exact combs. The combs are polybutadienes (1,4-addition) consisting of an H-skeleton with an additional off-center branch on the backbone. We chose to investigate a solution in order to obtain reliable nonlinear shear data in overlapping dynamic regions with the two different techniques. The transient measurements obtained by cone partitioned plate indicated the appearance of overshoots in both the shear stress and the first normal stress difference during start-up shear flow. Interestingly, the overshoots in the start-up normal stress difference started to occur only at rates above the inverse stretch time of the backbone, when the stretch time of the backbone was estimated in analogy with linear chains including the effects of dynamic dilution of the branches but neglecting the effects of branch point friction, in excellent agreement with the situation for linear polymers. Flow-birefringence measurements were performed in a Couette geometry, and the extracted steady-state shear and first normal stress differences were found to agree well with the mechanical data, but were limited to relatively low rates below the inverse stretch time of the backbone. Finally, the steady-state properties were found to be in good agreement with model predictions based on a nonlinear multimode tube model developed for linear polymers when the branches are treated as solvent.

  18. Synthesis of the Markov model of the thermochemical degradation of a polymer in solution

    Directory of Open Access Journals (Sweden)

    V. K. Bityukov

    2017-01-01

    Full Text Available The paper deals with the problem of mathematical modeling of thermochemical destruction process. The apparatus of Markov's chains is used to synthesize a mathematical model. The authors of the study suggest to consider the destruction process as a random one, where the system state changes, which is characterized by the proportion of macromolecules in each fraction of the molecular- and weight distribution. The intensities of transitions from one state to another characterize the corresponding rates of destruction processes for each fraction of the molecular- and weight distribution. The processes of crosslinking and polymerization in this work were neglected, and it was accepted that there is a probability of transition from any state with a lower order index (corresponding to fractions with higher molecular weights to any state with a higher index (corresponding to fractions with lower molecular weights. Markov's chain with discrete states and continuous time was taken as the mathematical model basis. Interactive graphical simulation environment MathWorksSimulink was used as a simulation environment. Experimental studies of polybutadiene destruction in solution were carried out to evaluate the mathematical model parameters. The GPC (gel-penetration chromatography data of the polybutadiene solution were used as the initial (starting data for estimating the polymer WMD (molecular weight distribution. Mean-square deviation of the calculated data from the experimental data for each fraction and at specified times was minimized for the numerical search of parameter values. The results of comparison of experimental and calculated on mathematical model data showed an error of calculations on the average about 5%, which indicates an acceptable error in estimating of polymer fractions proportions change during the process of destruction for the process under consideration and conditions.

  19. Ultrasound degradation of xanthan polymer in aqueous solution: Its scission mechanism and the effect of NaCl incorporation.

    Science.gov (United States)

    Saleh, H M; Annuar, M S M; Simarani, K

    2017-11-01

    Degradation of xanthan polymer in aqueous solution by ultrasonic irradiation was investigated. The effects of selected variables i.e. sonication intensity, irradiation time, concentration of xanthan gum and molar concentration of NaCl in solution were studied. Combined approach of full factorial design and conventional one-factor-at-a-time was applied to obtain optimum degradation at sonication power intensity of 11.5Wcm -2 , irradiation time 120min and 0.1gL -1 xanthan in a salt-free solution. Molecular weight reduction of xanthan gum under sonication was described by an exponential decay function with higher rate constant for polymer degradation in the salt free solution. The limiting molecular weight where fragments no longer undergo scission was determined from the function. The incorporation of NaCl in xanthan solution resulted in a lower limiting molecular weight. The ultrasound-mediated degradation of aqueous xanthan polymer chain agreed with a random scission model. Side chain of xanthan polymer is proposed to be the primary site of scission action. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. A free-volume modification of GEM-QC to correlate VLE and LLE in polymer solutions

    International Nuclear Information System (INIS)

    Radfarnia, H.R.; Taghikhani, V.; Ghotbi, C.; Khoshkbarchi, M.K.

    2004-01-01

    The generalized quasi-chemical (GEM-QC) model proposed by Wang and Vera is modified to correlate better the phase equilibrium and to overcome the shortcoming of the original model to predict the lower critical solution temperature (LCST) of binary polymer solutions. This shortcoming is mainly because the GEM-QC model does not consider the effect of free-volume, which is important in systems containing molecules with large size differences. The proposed modification is based on replacing the combinatorial term of the GEM-QC model by a term proposed by Kontogerogis et al., which includes the effect of the free-volume. The main advantage of the free volume generalized quasi-chemical (GEM-QC-FV) model over the original GEM-QC is its ability to predict the phase behaviour of binary polymer solutions with LCST behaviour. In addition, the free volume UNIQUAC (UNIQUAC-FV) model is used to correlate VLE and LLE experimental data for binary polymer solutions. The comparison of the results obtained from the GEM-QC-FV model and the UNIQUAC-FV model shows the superiority of the GEM-QC-FV model in correlating the VLE and LLE experimental data for binary polymer solutions

  1. Highly uniform resistive switching properties of amorphous InGaZnO thin films prepared by a low temperature photochemical solution deposition method.

    Science.gov (United States)

    Hu, Wei; Zou, Lilan; Chen, Xinman; Qin, Ni; Li, Shuwei; Bao, Dinghua

    2014-04-09

    We report on highly uniform resistive switching properties of amorphous InGaZnO (a-IGZO) thin films. The thin films were fabricated by a low temperature photochemical solution deposition method, a simple process combining chemical solution deposition and ultraviolet (UV) irradiation treatment. The a-IGZO based resistive switching devices exhibit long retention, good endurance, uniform switching voltages, and stable distribution of low and high resistance states. Electrical conduction mechanisms were also discussed on the basis of the current-voltage characteristics and their temperature dependence. The excellent resistive switching properties can be attributed to the reduction of organic- and hydrogen-based elements and the formation of enhanced metal-oxide bonding and metal-hydroxide bonding networks by hydrogen bonding due to UV irradiation, based on Fourier-transform-infrared spectroscopy, X-ray photoelectron spectroscopy, and Field emission scanning electron microscopy analysis of the thin films. This study suggests that a-IGZO thin films have potential applications in resistive random access memory and the low temperature photochemical solution deposition method can find the opportunity for further achieving system on panel applications if the a-IGZO resistive switching cells were integrated with a-IGZO thin film transistors.

  2. Discrepancy between different estimates of the hydrodynamic diameter of polymer-coated iron oxide nanoparticles in solution

    International Nuclear Information System (INIS)

    Regmi, R.; Gumber, V.; Subba Rao, V.; Kohli, I.; Black, C.; Sudakar, C.; Vaishnava, P.; Naik, V.; Naik, R.; Mukhopadhyay, A.; Lawes, G.

    2011-01-01

    We have synthesized iron oxide nanoparticles coated with a monolayer of dextran, with molecular weights of the polymer between 5 and 670 kDa. Transmission electron microscopy images confirm that the hard core has a crystalline diameter of approximately 12 nm. The hydrodynamic diameters of these coated nanoparticles in solution measured using dynamical light scattering and estimated from magnetic susceptibility studies vary from near 90 nm for the lightest polymer to 140 nm for the heaviest polymer. Conversely, fluorescence correlation spectroscopy measurements yield a diameter of approximately 55 nm for the 15–20 kDa dextran coated nanoparticles, which is consistent with the expected value estimated from the sum of the hard-core diameter and monolayer dextran coating. We discuss the implications of this discrepancy for applications involving polymer-coated magnetic nanoparticles.

  3. One-Dimensional Modelling of Polymer Flood Performance. Analytical and Graphical Solutions Modélisation de l'efficacité du déplacement unidimensionnel par injection de polymères. Solutions analytiques et graphiques

    Directory of Open Access Journals (Sweden)

    Grattoni C. A.

    2006-11-01

    Full Text Available A graphical method for simulating linear polymer flooding is proposed. The method is based upon the analytical solution of Darcy's law and continuity equation which describe the two-phase, one-dimensional, incompressible flow of oil and polymer solution through the reservoir rock. Continuous polymer injection and polymer slug injection are considered. Several physical mechanisms determining microscopic displacement efficiency are taken into account: resistance factor, residual resistance factor, retention composed by adsorption and mechanical entrapment, and inaccessible pore volume. Other properties are not considered: mixing and dispersion, shear and thermal degradation. This analytical-graphical model closely reproduces linear laboratory oil displacement experiments. Consequently, it can be used by the Field Engineer to rapidly estimate the additional oil recoverable by a linear polymer flood. On propose dans cet article une méthode graphique de simulation de l'injection de polymères dans le cas unidimensionnel. Cette méthode est basée sur la solution analytique de la loi de Darcy et de l'équation de continuité qui décrivent l'écoulement diphasique incompressible unidimen-sionnel d'huile et d'une solution de polymères à travers la roche réservoir. On examine l'injection continue et l'injection de bouchons de polymères. On prend en compte plusieurs mécanismes physiques qui déterminent l'efficacité du déplacement microscopique : facteur de ré-sistance, facteur de résistance résiduel, rétention due à l'adsorption et au piégeage mécanique et, enfin, volume des pores inacessibles. On ne tient pas compte des autres propriétés : mélange et dispersion, dégradation mécanique et thermique. Ce modèle analytique et graphique reproduit très directement les expériences de laboratoire de déplacement d'huile en milieu unidimensionnel. II peut donc être utilisé par l'ingénieur de chantier pour une estimation rapide de l

  4. Crystallization inhibitors for amorphous oxides

    International Nuclear Information System (INIS)

    Reznitskij, L.A.; Filippova, S.E.

    1993-01-01

    Data for the last 10 years, in which experimental results of studying the temperature stabilization of x-ray amorphous oxides (including R 3 Fe 5 O 12 R-rare earths, ZrO 2 , In 2 O 3 , Sc 2 O 3 ) and their solid solution are presented, are generalized. Processes of amorphous oxide crystallization with the production of simple oxides, solid solutions and chemical compounds with different polyhedral structure, are investigated. Energy and crystallochemical criteria for selecting the doping inhibitor-components stabilizing the amorphous state are ascertained, temperatures and enthalpies of amorpous oxide crystallization are determined, examination of certain provisions of iso,orphous miscibility theory is conducted

  5. Branched multifunctional polyether polyketals: variation of ketal group structure enables unprecedented control over polymer degradation in solution and within cells.

    Science.gov (United States)

    Shenoi, Rajesh A; Narayanannair, Jayaprakash K; Hamilton, Jasmine L; Lai, Benjamin F L; Horte, Sonja; Kainthan, Rajesh K; Varghese, Jos P; Rajeev, Kallanthottathil G; Manoharan, Muthiah; Kizhakkedathu, Jayachandran N

    2012-09-12

    Multifunctional biocompatible and biodegradable nanomaterials incorporating specific degradable linkages that respond to various stimuli and with defined degradation profiles are critical to the advancement of targeted nanomedicine. Herein we report, for the first time, a new class of multifunctional dendritic polyether polyketals containing different ketal linkages in their backbone that exhibit unprecedented control over degradation in solution and within the cells. High-molecular-weight and highly compact poly(ketal hydroxyethers) (PKHEs) were synthesized from newly designed α-epoxy-ω-hydroxyl-functionalized AB(2)-type ketal monomers carrying structurally different ketal groups (both cyclic and acyclic) with good control over polymer properties by anionic ring-opening multibranching polymerization. Polymer functionalization with multiple azide and amine groups was achieved without degradation of the ketal group. The polymer degradation was controlled primarily by the differences in the structure and torsional strain of the substituted ketal groups in the main chain, while for polymers with linear (acyclic) ketal groups, the hydrophobicity of the polymer may play an additional role. This was supported by the log P values of the monomers and the hydrophobicity of the polymers determined by fluorescence spectroscopy using pyrene as the probe. A range of hydrolysis half-lives of the polymers at mild acidic pH values was achieved, from a few minutes to a few hundred days, directly correlating with the differences in ketal group structures. Confocal microscopy analyses demonstrated similar degradation profiles for PKHEs within live cells, as seen in solution and the delivery of fluorescent marker to the cytosol. The cell viability measured by MTS assay and blood compatibility determined by complement activation, platelet activation, and coagulation assays demonstrate that PKHEs and their degradation products are highly biocompatible. Taken together, these data

  6. Evaluation of the numerical solution of polymer flooding; Avaliacao da solucao numerica da injecao de polimeros em reservatorios de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, Vinicius Ligiero; Pires, Adolfo Puime; Bedrikovetsky, Pavel G. [Universidade Estadual do Norte Fluminense (UENF), Macae, RJ (Brazil). Lab. de Engenharia e Exploracao do Petroleo (LENEP)

    2004-07-01

    Enhanced Oil Recovery (EOR) methods include injection of different fluids into reservoirs to improve oil displacement. The EOR methods may be classified into the following kinds: injection of chemical solutions, injection of solvents and thermal methods. The chemical fluids most commonly injected are polymers, surfactants, micellar solutions, etc. Displacement of oil by any of these fluids involves complex physico-chemical processes of interphase mass transfer, phase transitions and transport properties changes. These processes can be divided into two main categories: thermodynamical and hydrodynamical ones. They occur simultaneously during the displacement, and are coupled in the modern mathematical models of EOR. The model for one-dimensional displacement of oil by polymer solutions is analyzed in this paper. The Courant number is fixed, and we compare the results of different runs of a numerical simulator with the analytical solution of this problem. Each run corresponds to a different spatial discretization. (author)

  7. Free-radical-induced chain scission and cross-linking of polymers in aqueous solution. An overview

    International Nuclear Information System (INIS)

    Von Sonntag, C.

    2002-01-01

    Complete text of publication follows. In the radiolysis of N 2 O-saturated aqueous solutions OH are generated. In their reactions with polymers, they give rise to polymer-derived radicals. The kinetics of the formation and decay of these radicals are reviewed. The rate of reaction of a polymer with a reactive free radical is noticeably lower than that of an equivalent concentration of monomer due to the non-random distribution of the reaction sites. Once a larger number of radicals are formed on one polymer molecule, e.g. upon pulse radiolysis, close-by radicals recombine more rapidly while the more distant ones survive for much longer times than an equivalent concentration of freely diffusing radicals. Intermolecular cross-linking (between two polymer chains, increase in molecular weight) and intramolecular cross-linking (formation of small loops, no increase in polymer weight) are competing processes, and their relative yields thus depend on the dose rate and polymer concentration. Hydrogen-transfer reactions within the polymer, e.g. transformation of a secondary radical into a tertiary one, are common and facilitated by the high local density of reactive sites. Due to repulsive forces, the lifetime of radicals of charged polymers is substantially increased. This enables even relatively slow b-fragmentation reactions to become of importance. In the case of poly(methacrylic acid), where β-fragmentation is comparatively fast, this even leads to an unzipping, and as a consequence of the efficient release of methacrylic acid the situation of equilibrium polymerization is approached. Heterolytic β-fragmentation is possible when adequate leaving groups are available, e.g. in polynucleotides and DNA. In the presence of O 2 , chain scission occurs via oxyl radicals as intermediates. Some implications for technical applications are discussed

  8. Influence of complexing on physicochemical properties of polymer-salt solutions. Vliyanie kompleksoobrazovaniya na fiziko-khimicheskie svojstva polimerno-solevykh rastvorov

    Energy Technology Data Exchange (ETDEWEB)

    Ostroushko, A A; Yushkova, S M; Koridze, N V; Skobkoreva, N V; Zhuravleva, L I; Palitskaya, T A; Antropova, S V; Ostroushko, I P [Ural' skij Gosudarstvennyj Univ., Sverdlovsk (Russian Federation) AN SSSR, Moscow (Russian Federation). Inst. Obshchej i Neorganicheskoj Khimii

    1993-06-01

    Using the methods of spectrophotometry, viscosimetry, conductometry the influence of salt-polymer complexing processes on physicochemical prperties of aqueous solutions of yttrium, barium, copper nitrates and formates with polyvinyl alcohol was studied. Change of dynamic viscosity, specific electric conductivity of solutions in the process of complexing was shown. Thermal effects of salt-polymer interaction were measured. It is shown that decrease of transition temperature of polymer to plastic state in films, temperature and effective activation energy of salt decomposition is also connected with complexing. Effective values of surface tension on the boundary with air are measured. Coefficients of cation diffusion in polymer-salt solutions are estimated.

  9. Improvement of the physicochemical properties of Co-amorphous naproxen-indomethacin by naproxen-sodium

    DEFF Research Database (Denmark)

    Beyer, Andreas; Grohganz, Holger; Löbmann, Korbinian

    2017-01-01

    Improvement of the physicochemical properties of amorphous active pharmaceutical ingredients (APIs) applying the concept of co-amorphisation is a promising alternative to the use of polymer glass solutions. In co-amorphous systems, the physical stability and the dissolution rate of the involved c...... or full exchange of naproxen by its sodium salt was performed, which may present a general optimization method to improve co-amorphous systems....... In the present study, it was thus tested if the physicochemical properties of co-amorphous naproxen-indomethacin could be optimized by incorporation of the naproxen sodium into the system. Three different co-amorphous systems in nine different molar ratios were prepared by quench-cooling: naproxen...... components may be improved in comparison to the respective single amorphous phases. However, for the co-amorphous naproxen-indomethacin model system it has been reported that recrystallization could not be prevented for more than 112days regardless of the applied preparation method and blend ratio...

  10. (Liquid plus liquid) equilibria of binary polymer solutions using a free-volume UNIQUAC-NRF model

    DEFF Research Database (Denmark)

    Radfarnia, H.R.; Ghotbi, C.; Taghikhani, V.

    2006-01-01

    + liquid) equilibria (LLE) for a number of binary polymer solutions at various temperatures. The values for the binary characteristic energy parameters for the proposed model and the FV-UNIQUAC model along with their average relative deviations from the experimental data were reported. It should be stated...

  11. Dual Function Behavior of Carbon Fiber-Reinforced Polymer in Simulated Pore Solution

    Directory of Open Access Journals (Sweden)

    Ji-Hua Zhu

    2016-02-01

    Full Text Available The mechanical and electrochemical performance of carbon fiber-reinforced polymer (CFRP were investigated regarding a novel improvement in the load-carrying capacity and durability of reinforced concrete structures by adopting CFRP as both a structural strengthener and an anode of the impressed current cathodic protection (ICCP system. The mechanical and anode performance of CFRP were investigated in an aqueous pore solution in which the electrolytes were available to the anode in a cured concrete structure. Accelerated polarization tests were designed with different test durations and various levels of applied currents in accordance with the international standard. The CFRP specimens were mechanically characterized after polarization. The measured feeding voltage and potential during the test period indicates CFRP have stable anode performance in a simulated pore solution. Two failure modes were observed through tensile testing. The tensile properties of the post-polarization CFRP specimens declined with an increased charge density. The CFRP demonstrated success as a structural strengthener and ICCP anode. We propose a mathematic model predicting the tensile strengths of CFRP with varied impressed charge densities.

  12. Diffusion of inorganic ion aqueous solution into hydrophilic polymer fiber and molecular orientation

    International Nuclear Information System (INIS)

    Kawaguchi, Akio

    2001-01-01

    The adsorption process of iodine to nylon 6 (polyamide-6), as well as deiodination process, has been an issue of controversy in the past half century from the view points related to the conversion of hydrogen bonding (α phase vs. γ phase). In the researches since late '80s, it has been revealed that the adsorption or inclusion of iodine to polyamides causes formations of various kind of structures to be called complexes whether they are crystalline or amorphous, and the formation of complex is reflected on the physical properties (especially on adsorption and ion mobility). Among them, it has been reported about both the doubly-oriented samples and the non-oriented samples that the ion diffusion causes molecular chain orientation during the complex formation. In the present experiment the change of molecular orientation in the early stage of the complex formation is studied by the time-resolved measurement with synchrotron radiation facility at SPring-8. Through-view and edge-view diffraction patterns of doubly oriented nylon 6 and non-oriented one were measured at 0.1 nm wavelength introducing I2-KI aqueous solution. It is observed that the formation of complex (i.e. diffusion of polyiodine) is attained in about 0.3 to 0.4 sec. even in non-oriented sample. From the analysis of the diffraction behavior, it is summarized that the inclusion of iodine into the crystalline phase of nylon 6 is possible from either sides of the molecular directions, namely normal diffusion and parallel diffusion. It is concluded that the diffusion and adsorption of inorganic ions including polyiodine to polyamide causes not only the formation of complexes in the crystalline phase but also give motive force to change structure in the surrounding non-crystalline region. (S. Funahashi)

  13. Mechanics of amorphous solids—identification and constitutive modelling

    NARCIS (Netherlands)

    van Dommelen, J.A.W.; Estevez, R.

    2018-01-01

    Both polymers and metals can be in an organised crystalline or amorphous glassy state, where for polymers usually at least a part of the structure is amorphous and metals are in a glassy state only when processed under special conditions. At the 15th European Mechanics of Materials Conference in

  14. 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

  15. A salt water battery with high stability and charging rates made from solution processed conjugated polymers with polar side chains

    KAUST Repository

    Moia, Davide

    2017-11-28

    We report a neutral salt water based battery which uses p-type and n-type solution processed polymer films as the cathode and the anode of the cell. The specific capacity of the electrodes (approximately 30 mAh cm-3) is achieved via formation of bipolarons in both the p-type and n-type polymers. By engineering ethylene glycol and zwitterion based side chains attached to the polymer backbone we facilitate rapid ion transport through the non-porous polymer films. This, combined with efficient transport of electronic charge via the conjugated polymer backbones, allowed the films to maintain constant capacity at high charge and discharge rates (>1000 C-rate). The electrodes also show good stability during electrochemical cycling (less than 30% decrease in capacity over >1000 cycles) and an output voltage up to 1.4 V. The performance of these semiconducting polymers with polar side-chains demonstrates the potential of this material class for fast-charging, water based electrochemical energy storage devices.

  16. Effect of crystallization on corrosion behavior of Fe40Ni38B18Mo4 amorphous alloy in 3.5% sodium chloride solution

    DEFF Research Database (Denmark)

    Wu, Y.F.; Chiang, Wen-Chi; Wu, J.K.

    2008-01-01

    After the crystallization of F40Ni38B18Mo4 amorphous alloy by vacuum annealing, the corrosion resistance of its crystalline state shows inferior to its amorphous state due to the local cell action between Ni phase and (Fe, Ni, Mo)(23)B-6 phase in matrix.......After the crystallization of F40Ni38B18Mo4 amorphous alloy by vacuum annealing, the corrosion resistance of its crystalline state shows inferior to its amorphous state due to the local cell action between Ni phase and (Fe, Ni, Mo)(23)B-6 phase in matrix....

  17. A comparison of amorphous calcium carbonate crystallization in aqueous solutions of MgCl2 and MgSO4: implications for paleo-ocean chemistry

    Science.gov (United States)

    Han, Mei; Zhao, Yanyang; Zhao, Hui; Han, Zuozhen; Yan, Huaxiao; Sun, Bin; Meng, Ruirui; Zhuang, Dingxiang; Li, Dan; Liu, Binwei

    2018-04-01

    Based on the terminology of "aragonite seas" and "calcite seas", whether different Mg sources could affect the mineralogy of carbonate sediments at the same Mg/Ca ratio was explored, which was expected to provide a qualitative assessment of the chemistry of the paleo-ocean. In this work, amorphous calcium carbonate (ACC) was prepared by direct precipitation in anhydrous ethanol and used as a precursor to study crystallization processes in MgSO4 and MgCl2 solutions having different concentrations at 60 °C (reaction times 240 and 2880 min). Based on the morphology of the aragonite crystals, as well as mineral saturation indices and kinetic analysis of geochemical processes, it was found that these crystals formed with a spherulitic texture in 4 steps. First, ACC crystallized into columnar Mg calcite by nearly oriented attachment. Second, the Mg calcite changed from columnar shapes into smooth dumbbell forms. Third, the Mg calcite transformed into rough dumbbell or cauliflower-shaped aragonite forms by local dissolution and precipitation. Finally, the aragonite transformed further into spherulitic radial and irregular aggregate forms. The increase in Ca2+ in the MgSO4 solutions compared with the MgCl2 solutions indicates the fast dissolution and slow precipitation of ACC in the former solutions. The phase transition was more complete in the 0.005 M MgCl2 solution, whereas Mg calcite crystallized from the 0.005 M MgSO4 solution, indicating that Mg calcite could be formed more easily in an MgSO4 solution. Based on these findings, aragonite and Mg calcite relative to ACC could be used to provide a qualitative assessment of the chemistry of the paleo-ocean. Therefore, calcite seas relative to high-Mg calcite could reflect a low concentration MgSO4 paleo-ocean, while aragonite seas could be related to an MgCl2 or high concentration of MgSO4 paleo-ocean.

  18. Investigating the particle to fibre transition threshold during electrohydrodynamic atomization of a polymer solution

    Energy Technology Data Exchange (ETDEWEB)

    Husain, O.; Lau, W.; Edirisinghe, M.; Parhizkar, M., E-mail: maryam.parhizkar.09@ucl.ac.uk

    2016-08-01

    Electrohydrodynamic atomization (EHDA) is a key research area for producing micro and nano-sized structures. This process can be categorized into two main operating regimes: electrospraying for particle generation and electrospinning for fibre production. Producing particles/fibres of the desired size or morphology depends on two main factors; properties of the polymeric solution used and the processing conditions including flow rate, applied voltage and collection distance. In this work the particle-fibre transition region was analyzed by changing the polymer concentration of PLGA poly (lactic-co-glycolic acid) in acetone between 2 and 25 wt%. Subsequently the processing conditions were adjusted to study the optimum transition parameters. Additionally the EHDA configuration was also modified by adding a metallic plate to observe the deposition area. The diameter and the distance of the plate from the capillary tip were adjusted to investigate variations in particle and fibre morphologies as well. It was found that complete transition from particles to fibres occurs at 20 wt% indicating concentration to be the dominant criterion. Low flow rates yielded fibres without beads. However the applied voltage and distance between the tip of the nozzle jetting the polymer solution and collector (working distance) did not yield definitive results. Reducing the collector distance and increasing applied voltages produces smooth as well as beaded fibres. Addition of a metal plate reduces particle size by ~ 1 μm; the fibre size increases especially with increasing plate diameter while bead density and size reduces when the disc is fixed closer to the capillary tip. Additionally, the deposition area is reduced by 70% and 57% with the addition of metal plates of 30 mm and 60 mm, respectively. The results indicate that a metal plate can be utilized further to tune the particle/fibre size and morphology and this also significantly increases the yield of EHDA process which is

  19. Certain laws governing the influence of high molecular polymer additives on specific electrical conductivity and viscosity of zincate alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Dmitrenko, V.Ye.; Toropetsera, T.N.; Zubov, M.S.

    1983-01-01

    A study was made of the influence of polymer additives of different nature: polyelectrolyte, copolymer of ethylene with maleic anhydride, polymethacrylic acid and nonpolyectrolyte copolymer of vinyl alcohol with vinyleneglycol and polyvinyleneglycol on specific electrical conductance and viscosity of the zincate alkaline solution. It is indicated that with an increase in the content of additives, the specific conductance of the solution diminishes according to a linear law, while the viscosity rises. The additives of polyelectrolyte nature reduce more strongly the specific conductance and increase the viscosity than the nonpolyelectrolyte additives. From a comparison of the data on specific conductance and viscosity the following conclusion is drawn: the more the polymer ''structures'' the zincate alkaline solution, the more strongly it reduces its specific electrical conductance.

  20. Removal of phenol from aqueous solution using polymer inclusion membrane based on mixture of CTA and CA

    Science.gov (United States)

    Benosmane, Nadjib; Boutemeur, Baya; Hamdi, Safouane M.; Hamdi, Maamar

    2018-03-01

    Nowadays, there are increasingly stringent regulations requiring more and more treatment of industrial effluents to generate product waters which could be easily reused or disposed of to the environment without any harmful effects. In the present work, the removal of phenol from aqueous solution across polymer inclusion membrane (PIM), based on mixture of cellulose triacetate and cellulose acetate as support (75/25%), calix[4]resorcinarene derivative as a carrier and 2-nitrophenyl octyl ether (2-NPOE) as plasticizer was investigated. The experimental part of this investigation involved the influence of carrier nature, plasticizer concentration, pH phases, and phenol initial concentration on the removal efficiency of phenol from synthetic wastewater. A PIM containing 0.1 g (of mixture polymer), (0.15 g/g mixture of polymer) of carrier and (0.03 ml/g mixture of polymer) of 2-NPOE provided the highest percentage of phenol removal efficiency over a 6-day transport; the removal was found to be about 95%, indeed the removal was found to be highly dependent of pH phases. The feed solution in these transport experiments was at pH 2, while the stripping solution contained 0.20 M NaOH. This study claims that the PIM with a mixture of cellulose derivatives can be used effectively to remove phenols from wastewaters.

  1. The degree of doubly charged cation binding in solutions of (co)polymers of 2-acrylamido-2-methylpropanesulfonic acid salts

    International Nuclear Information System (INIS)

    Kurenkov, V.F.; Kolesnikova, I.Yu.; Antonovich, O.A.

    2002-01-01

    The degree of binding the ions of the alkaline-earth metals (M = Mg, Ca, Sr, Ba) by the polysulfate anions in the aqueous solutions of the polymers of the 2-acrylamido-2-methylpropanesulfonic acid (N-AMS) salts and their binary copolymers with the acrylamide (AA) and N-vinylpyrrolidone (VP) is quantitatively evaluated through the Terayama and Wall viscosimetric method. It is established, that the degree of binding decreases in the Sr>Ca>Mg sequence for the N-AMS polymer salts and in the reverse sequence (Mg>Ca>Sr(Ba)) for the binary copolymers of the N-AMS salts with AA and VP [ru

  2. Solution processing of polymer semiconductor: Insulator blends-Tailored optical properties through liquid-liquid phase separation control

    KAUST Repository

    Hellmann, Christoph

    2014-12-17

    © 2014 Wiley Periodicals, Inc. It has been demonstrated that the 0-0 absorption transition of poly(3-hexylthiophene) (P3HT) in blends with poly(ethylene oxide) (PEO) could be rationally tuned through the control of the liquid-liquid phase separation process during solution deposition. Pronounced J-like aggregation behavior, characteristic for systems of a low exciton band width, was found for blends where the most pronounced liquid-liquid phase separation occurred in solution, leading to domains of P3HT and PEO of high phase purity. Since liquid-liquid phase separation could be readily manipulated either by the solution temperature, solute concentration, or deposition temperature, to name a few parameters, our findings promise the design from the out-set of semiconductor:insulator architectures of pre-defined properties by manipulation of the interaction parameter between the solutes as well as the respective solute:solvent system using classical polymer science principles.

  3. Solution processing of polymer semiconductor: Insulator blends-Tailored optical properties through liquid-liquid phase separation control

    KAUST Repository

    Hellmann, Christoph; Treat, Neil D.; Scaccabarozzi, Alberto D.; Razzell Hollis, Joseph; Fleischli, Franziska D.; Bannock, James H.; de Mello, John; Michels, Jasper J.; Kim, Ji-Seon; Stingelin, Natalie

    2014-01-01

    © 2014 Wiley Periodicals, Inc. It has been demonstrated that the 0-0 absorption transition of poly(3-hexylthiophene) (P3HT) in blends with poly(ethylene oxide) (PEO) could be rationally tuned through the control of the liquid-liquid phase separation process during solution deposition. Pronounced J-like aggregation behavior, characteristic for systems of a low exciton band width, was found for blends where the most pronounced liquid-liquid phase separation occurred in solution, leading to domains of P3HT and PEO of high phase purity. Since liquid-liquid phase separation could be readily manipulated either by the solution temperature, solute concentration, or deposition temperature, to name a few parameters, our findings promise the design from the out-set of semiconductor:insulator architectures of pre-defined properties by manipulation of the interaction parameter between the solutes as well as the respective solute:solvent system using classical polymer science principles.

  4. Amorphous superconductors

    International Nuclear Information System (INIS)

    Missell, F.P.

    1985-01-01

    We describe briefly the strong coupling superconductivity observed in amorphous alloys based upon simple metals. For transition metal alloys we discuss the behavior of the superconducting transition temperature T c , the upper critical field H (sub)c2 and the critical current J c . A survey of current problems is presented. (author) [pt

  5. Application des techniques de diffusion de la lumière des rayons x et des neutrons à l'étude des systèmes colloïdaux. Deuxième partie : étude des différents systèmes : polymères en solution à l'état solide, solutions micellaires, systèmes fractals Application of Light, X-Ray and Neutron Diffusion Techniques to the Study of Colloidal Systems. Part Two: Research on Different Systems: Polymers in Solution in the Solid State, Micellar Solutions, Fractals Systems

    Directory of Open Access Journals (Sweden)

    Espinat D.

    2006-11-01

    Full Text Available Cet article fait suite à la première partie (Revue Inst. Franç. du Pétrole, vol. 45, n°6, novembre-décembre 1990 concernant l'application des techniques de diffusion de la lumière, des rayons X et des neutrons à l'étude des systèmes colloïdaux et plus précisément à la présentation théorique des trois méthodes. L'objet de cette deuxième partie est la présentation non exhaustive de quelques domaines d'applications. Nous nous attacherons tout particulièrement à présenter les potentialités des méthodes pour la caractérisation de systèmes colloïdaux ou divisés rencontrés dans de nombreuses branches d'activité de l'industrie pétrolière. Nous aborderons dans une première partie les solutions polymériques et colloïdales. En particulier nous nous attarderons sur l'importance des techniques de diffusion pour la caractérisation des polymères en solution et des solutions micellaires. Nous verrons également quelles informations la diffusion centrale peut apporter sur la macrostructure des polymères cristallisés ou amorphes à l'état solide. De nombreux systèmes présentent une structure de type fractal ; après présentation de quelques exemples, nous montrerons que les méthodes de diffusion peuvent apporter certaines informations sur ces matériaux, notamment la dimension fractale. This article is the second one (the first one was published in Revue de l'Institut Français du Pétrole No. 6, NovemberDecember 1990 concerning the application of techniques of light scattering, X rays and neutrons to the analysis of colloidal systems and more specifically to the theoretical description of the three methods. The aim of this second part is to make a nonexhaustive description of several fields of applications. A special effort is made to describe the potential of these methods for characterizing colloidal or divided systems encountered in a great many activities involving the petroleum industry. The first part of this

  6. ``Living polymers'' in organic solvents : stress relaxation in bicopper tetracarboxylate/tert-butyl cyclohexane solutions

    Science.gov (United States)

    Terech, P.; Maldivi, P.; Dammer, C.

    1994-10-01

    Viscoelastic solutions of a bicopper tetracarboxylate complex in tert-butylcyclohexane have been studied by dynamic rheology in a wide range of concentrations (0.5-1.5 % volume fraction). The zero shear viscosity, the elastic modulus, the terminal stress relaxation time and the height of the high-frequency dip, in a Cole-Cole representation of the complex elastic modulus, follow scaling laws. The related exponents are discussed in the context of the physics of “living polymers” : a term used to describe worm-like species undergoing scission/recombination reactions competing mainly with the reptation motions of the chains. The current system, made up of molecular threads (17.5 Å diameter) of Cu2(O2C-CH(C2H5)C4H9)4 in the apolar solvent, is representative of a “living polymer” where, instead of mechanisms involving transient star polymeric crosslinks, a reversible scission mechanism prevails. The dynamics in the high-frequency range evolves from a regime where reptation is the dominant relaxation mechanism to a cross-over regime where “breathing” fluctuations and Rouse motions become important. Large modifications of the stress relaxation function occur for more concentrated systems. The binary system is the first example of a “living polymer” in an organic solvent and exhibits elastic moduli (G ≈ ca. 120 Pa à φ = 1 %) which are at least 20 times larger than those found for the aqueous “living polymer” systems. Les solutions viscoélastiques d'un tétracarboxylate binucléaire de cuivre dans le tert-butylcyclohexane sont étudiées par rhéologie en mode dynamique dans une gamme étendue de concentrations (0,5 %-15,5 %). La viscosité à gradient nul, le module élastique, le temps terminal de relaxation et la hauteur du puits à haute fréquence, dans une représentation Cole-Cole du module élastique complexe, suivent des lois d'échelles. Les exposants correspondants sont discutés dans le contexte de la physique des “polymères vivants

  7. Low-temperature fabrication of an HfO2 passivation layer for amorphous indium-gallium-zinc oxide thin film transistors using a solution process.

    Science.gov (United States)

    Hong, Seonghwan; Park, Sung Pyo; Kim, Yeong-Gyu; Kang, Byung Ha; Na, Jae Won; Kim, Hyun Jae

    2017-11-24

    We report low-temperature solution processing of hafnium oxide (HfO 2 ) passivation layers for amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs). At 150 °C, the hafnium chloride (HfCl 4 ) precursor readily hydrolyzed in deionized (DI) water and transformed into an HfO 2 film. The fabricated HfO 2 passivation layer prevented any interaction between the back surface of an a-IGZO TFT and ambient gas. Moreover, diffused Hf 4+ in the back-channel layer of the a-IGZO TFT reduced the oxygen vacancy, which is the origin of the electrical instability in a-IGZO TFTs. Consequently, the a-IGZO TFT with the HfO 2 passivation layer exhibited improved stability, showing a decrease in the threshold voltage shift from 4.83 to 1.68 V under a positive bias stress test conducted over 10,000 s.

  8. Method of preparing Ru-immobilized polymer-supported catalyst for hydrogen generation from NaBH{sub 4} solution

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ching-Wen; Chen, Chuh-Yung; Huang, Yao-Hui [Department of Chemical Engineering, National Cheng Kung University, No.1, University Road, Tainan City 70101 (China)

    2009-03-15

    A method of preparing a polymer-supported catalyst for hydrogen generation is introduced in this article. This polymer-supported catalyst is the structure of ruthenium (Ru) nanoparticle immobilized on a monodisperse polystyrene (PSt) microsphere. The diameter of the Ru nanoparticle is around 16 nm, and the diameter of the PSt microsphere is 2.65 um. This preparation method is accomplished by two unique techniques: one is sodium lauryl sulfate/sodium formaldehyde sulfoxylate (SLS/SFS) interface-initiated system, the other is 2-methacrylic acid 3-(bis-carboxymethylamino)-2-hydroxy-propyl ester (GMA-IDA) chelating monomer. By taking advantage of these two techniques, Ru{sup 3+} ion will be chelated and then reduced to Ru{sup (0)} nanoparticle over PSt surface predominantly. The hydrolysis of alkaline sodium borohydride (NaBH{sub 4}) solution catalyzed by this Ru-immobilized polymer-supported catalyst is also examined in this article. It reveals that the hydrogen generation rate is 215.9 ml/min g-cat. in a diluted solution containing 1 wt.% NaBH{sub 4} and 1 wt.% NaOH, and this Ru-immobilized polymer-supported catalyst could be recycled during the reaction. (author)

  9. Solution processable 2-(trityloxy)ethyl and tert-butyl group containing amorphous molecular glasses of pyranylidene derivatives with light-emitting and amplified spontaneous emission properties

    Science.gov (United States)

    Zarins, Elmars; Vembris, Aivars; Misina, Elina; Narels, Martins; Grzibovskis, Raitis; Kokars, Valdis

    2015-11-01

    Small organic molecules with incorporated 4H-pyran-4-ylidene (pyranylidene) fragment as the π-conjugation system which bonds the electron acceptor fragment (A) with electron donor part (D) in the molecule - also well known as derivatives of 4-(dicyano-methylene)-2-methyl-6-[p-(dimethylamino)styryl]-4H-pyran (DCM) laser dye-have attracted considerable attention of scientists as potential new generation materials for organic photonics and molecular electronics due to their low-cost fabrication possibility, flexibility and low-weight. Six glassy derivatives of 4H-pyran-4-ylidene (pyranylidene) with attached bulky 2-(trityloxy)ethyl and tert-butyl groups are described in this report. Almost all of the synthesized compounds form good optical quality transparent amorphous films from volatile organic solvents and could be obtained in good yields up to 75%. Their light emission in solution and thin solid films is in the range of 600-700 nm, they are thermally stable and show glass transition in the range of 108-158 °C. The amplified spontaneous emission threshold values of the neat films of the glassy pyranylidene derivatives vary from 155 to 450 μJ/cm2 and their HOMO and LUMO energy levels are between of those of tris(8-hydroxy quinolinato) aluminum (Alq3). The photoluminescence quantum yields of the glassy compounds are in the range from 1% to about 7.7% and their electroluminescence properties have been investigated. Therefore, glassy pyranylidene derivatives could be a very potential low-cost solution processable materials for Alq3 hosted light-amplification and light-emitting application studies.

  10. (Surfactant + polymer) interaction parameter studied by (liquid + liquid) equilibrium data of quaternary aqueous solution containing surfactant, polymer, and salt

    Energy Technology Data Exchange (ETDEWEB)

    Foroutan, Masumeh [Physical Chemistry Department, School of Chemistry, College of Science, University of Tehran, 14155-6455 Tehran (Iran, Islamic Republic of)], E-mail: foroutan@khayam.ut.ac.ir; Heidari, Nosrat; Mohammadlou, Maryam [Chemistry Department, Faculty of Science, Uremia University, Uremia (Iran, Islamic Republic of); Sojahrood, Amin Jafari [Physics Department, Faculty of Science, Uremia University, Uremia (Iran, Islamic Republic of)

    2009-02-15

    (Liquid + liquid) equilibrium (LLE) data of quaternary aqueous system containing polyoxyethylene (20) cetyl ether (with abbreviation name Brij 58, non-ionic surfactant), diammonium hydrogen phosphate, and poly ethylene glycol (PEG) with three molar masses {l_brace}M{sub W} = (1000, 6000, and 35,000) g . mol{sup -1}{r_brace} have been determined experimentally at T = 313.15 K. Furthermore, the Flory-Huggins theory with two electrostatic terms (Debye-Hueckel and Pitzer-Debye-Hueckel equations) have been used to calculate the phase behavior of the quaternary systems and (surfactant + polymer) interaction parameter as well as interaction parameters between other species. Temperature dependency of the parameters of the Flory-Huggins theory has been obtained. Also an effort have been done to show that addition of PEG as well as increasing the temperature can shift the binodal curves of the ternary aqueous system containing surfactant and salt to lower mole fraction of salt. Also the effect of polymer molar mass on the binodal diagram displacement has been discussed.

  11. Spontaneous Structuration of Hydrophobic Polymer Surfaces in Contact with Salt Solutions

    NARCIS (Netherlands)

    Sîretanu, Igor; Saadaoui, Hassan; Chapel, Jean Paul; Drummond, Carlos; Rodriguez-Hernandez, Juan; Drummond, Carlos

    2015-01-01

    It has been described in previous chapters how spontaneous instabilities related to interfacial phenomena can be used to produce controlled patterns on polymer surfaces. Strategies of polymer patterning assisted by dewetting or water drop condensation were described. In this chapter we present a

  12. Spinning process variables and polymer solution effects in the die-swell phenomenon during hollow fiber membranes formation

    Directory of Open Access Journals (Sweden)

    Pereira C.C.

    2000-01-01

    Full Text Available During hollow fiber spinning many variables are involved whose effects are still not completely clear. However, its understanding is of great interest because the control of these variables may originate membranes with the desired morphologies and physical properties. In this work, the phase inversion process induced by the immersion precipitation technique was applied to prepare hollow fibers membranes. It was verified that some of the variables involved, can promote a visco-elastic polymer solution expansion, called die-swell phenomenon, which is undesired since it may lead to low reproducibility of the permeation properties. The effects of the distance between spinneret and precipitation bath, the bore liquid composition, and the polymer solution composition were analyzed and discussed in order to avoid this phenomenon. According to the results, it was verified that the parameters investigated might promote a delay precipitation, which restrained the visco-elastic expansion.

  13. Sorption of 2-Chlorophenol from aqueous solutions by functionalized cross-linked polymers

    Directory of Open Access Journals (Sweden)

    Rodrigo Martins Fráguas

    2013-01-01

    Full Text Available This manuscript describes the synthesis of three polymers based on styrene (STY, divinylbenzene (DVB and two different vinyl monomers: methyl methacrylate (MMA and acrylonitrile (AN. The STY-DVB, STY-DVB-MMA and STY-DVB-AN polymers were synthesized employing the aqueous suspension technique. Reaction yields were 73%, 81% and 75%, respectively. They were morphological and chemically characterized using different techniques. The extraction capacity of the polymers was evaluated using 2-chlorophenol. The polymer extraction capacities were evaluated varying contact time the (1 h, 3 h and 5 h, temperature (30 °C, 35 °C and 40 °C, and pH (3, 5.6 and 8. The STY-DVB-AN polymer was the most efficient; it removed around 95% of the analyte using a contact time 50 h.

  14. Research on the structure in solution of optically active synthetic polymers (propylene polysulphide, propylene polyoxide, tertio-butyl polysulphide)

    International Nuclear Information System (INIS)

    Sarrazin, Brigitte

    1971-03-01

    It was proposed to study the structure of sulphur-containing synthetic polymers, stereo-regular, optically active in solution and able to adopt a spiral conformation, with special reference to propylene polysulphide. Two methods were used, the first mathematical (conformational energy calculations) and the second physico-chemical, essentially spectroscopic. By conformational analysis it is possible to choose the most probable structures liable to be adopted by a given polymer in solution while the spectro-polarimetric study should, in principle, invalidate or confirm certain of these hypotheses. The conformational energy calculations showed that in fact there is no energy conformation low enough to be stable in solution. Strictly speaking however we can refer to a region of stability in which steric hindrance is low and many energy minima exist. These minima are indistinguishable both by their energy values and by their spatial localizations and are all enclosed in the region bounded by the barriers due to steric hindrance. This uncertainty does not arise from approximations made in the calculations, but from the multitude of stereochemical structure possible. Investigations into the variation of the optical rotary dispersion and the circular dichroism as a function of temperature indicated the existence of three or more equilibrium states in the dioxane. The spectra appear to be the summation of the optical activities of the numerous simultaneously possible conformations. It appears that polymers, such as propylene polysulphide or propylene polyoxide do not have stable structures in solution. These are molecules of great flexibility possessing a large number of degrees of freedom. These properties distinguish them from the natural polymers, carrying precise information, such as DNA which must consequently have stable conformations. (author) [fr

  15. Hydrodynamic fluctuations, nonequilibrium equations of state, and the shift of the spinodal line in polymer solutions under flow

    International Nuclear Information System (INIS)

    Criado-Sancho, M.; Casas-Vazquez, J.; Jou, D.

    1997-01-01

    In the literature, the shift of the spinodal line of polymer solutions under flow is attributed either to an actual shift of the spinodal due to a nonequilibrium modification of the equation of state for the chemical potential, or to an apparent shift due to an increase of hydrodynamic fluctuations owing to the flow. Here we see that both approaches are compatible and that both effects add up. copyright 1997 The American Physical Society

  16. Using in-situ polymerization of conductive polymers to enhance the electrical properties of solution-processed carbon nanotube films and fibers.

    Science.gov (United States)

    Allen, Ranulfo; Pan, Lijia; Fuller, Gerald G; Bao, Zhenan

    2014-07-09

    Single-walled carbon nanotubes/polymer composites typically have limited conductivity due to a low concentration of nanotubes and the insulating nature of the polymers used. Here we combined a method to align carbon nanotubes with in-situ polymerization of conductive polymer to form composite films and fibers. Use of the conducting polymer raised the conductivity of the films by 2 orders of magnitude. On the other hand, CNT fiber formation was made possible with in-situ polymerization to provide more mechanical support to the CNTs from the formed conducting polymer. The carbon nanotube/conductive polymer composite films and fibers had conductivities of 3300 and 170 S/cm, respectively. The relatively high conductivities were attributed to the polymerization process, which doped both the SWNTs and the polymer. In-situ polymerization can be a promising solution-processable method to enhance the conductivity of carbon nanotube films and fibers.

  17. Emerging trends in the stabilization of amorphous drugs.

    Science.gov (United States)

    Laitinen, Riikka; Löbmann, Korbinian; Strachan, Clare J; Grohganz, Holger; Rades, Thomas

    2013-08-30

    The number of active pharmaceutical substances having high therapeutic potential but low water solubility is constantly increasing, making it difficult to formulate these compounds as oral dosage forms. The solubility and dissolution rate, and thus potentially the bioavailability, of these poorly water-soluble drugs can be increased by the formation of stabilized amorphous forms. Currently, formulation as solid polymer dispersions is the preferred method to enhance drug dissolution and to stabilize the amorphous form of a drug. The purpose of this review is to highlight emerging alternative methods to amorphous polymer dispersions for stabilizing the amorphous form of drugs. First, an overview of the properties and stabilization mechanisms of amorphous forms is provided. Subsequently, formulation approaches such as the preparation of co-amorphous small-molecule mixtures and the use of mesoporous silicon and silica-based carriers are presented as potential means to increase the stability of amorphous pharmaceuticals. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Elucidation of the Structure Formation of Polymer-Conjugated Proteins in Solution and Block Copolymer Templates

    Science.gov (United States)

    Ferebee, Rachel L.

    The broader technical objective of this work is to contribute to the development of enzyme-functionalized nanoporous membranes that can function as autonomous and target selective dynamic separators. The scientific objective of the research performed within this thesis is to elucidate the parameters that control the mixing of proteins in organic host materials and in block copolymers templates in particular. A "biomimetic" membrane system that uses enzymes to selectively neutralize targets and trigger a change in permeability of nanopores lined with a pH-responsive polymer has been fabricated and characterized. Mechanical and functional stability, as well as scalability, have been demonstrated for this system. Additional research has focused on the role of polymeric ligands on the solubility characteristics of the model protein, Bovine Serum Albumin (BSA). For this purpose BSA was conjugated with poly(ethylene glycol) (PEG) ligands of varied degree of polymerization and grafting density. Combined static and dynamic light scattering was used (in conjunction with MALDI-TOF) to determine the second virial coefficient in PBS solutions. At a given mass fraction PEG or average number of grafts, the solubility of BSA-PEG conjugates is found to increase with the degree of polymerization of conjugated PEG. This result informs the synthesis of protein-conjugate systems that are optimized for the fabrication of block copolymer blend materials with maximum protein loading. Blends of BSA-PEG conjugates and block copolymer (BCP) matrices were fabricated to evaluate the dispersion morphology and solubility limits in a model system. Electron microscopy was used to evaluate the changes in lamellar spacing with increased filling fraction of BSA-PEG conjugates.

  19. Determination of the interaction parameter and topological scaling features of symmetric star polymers in dilute solution

    KAUST Repository

    Rai, Durgesh K.; Beaucage, Gregory; Ratkanthwar, Kedar; Beaucage, Peter; Ramachandran, Ramnath; Hadjichristidis, Nikolaos

    2015-01-01

    Star polymers provide model architectures to understand the dynamic and rheological effects of chain confinement for a range of complex topological structures like branched polymers, colloids, and micelles. It is important to describe the structure of such macromolecular topologies using small-angle neutron and x-ray scattering to facilitate understanding of their structure-property relationships. Modeling of scattering from linear, Gaussian polymers, such as in the melt, has applied the random phase approximation using the Debye polymer scattering function. The Flory-Huggins interaction parameter can be obtained using neutron scattering by this method. Gaussian scaling no longer applies for more complicated chain topologies or when chains are in good solvents. For symmetric star polymers, chain scaling can differ from ν=0.5(df=2) due to excluded volume, steric interaction between arms, and enhanced density due to branching. Further, correlation between arms in a symmetric star leads to an interference term in the scattering function first described by Benoit for Gaussian chains. In this work, a scattering function is derived which accounts for interarm correlations in symmetric star polymers as well as the polymer-solvent interaction parameter for chains of arbitrary scaling dimension using a hybrid Unified scattering function. The approach is demonstrated for linear, four-arm and eight-arm polyisoprene stars in deuterated p-xylene.

  20. Experimental Study on the Properties and Displacement Effects of Polymer Surfactant Solution

    Directory of Open Access Journals (Sweden)

    Ke-Liang Wang

    2013-01-01

    Full Text Available Based on the characteristics of oil reservoirs and the requirements of further enhancing oil recovery at high water cut stage of Pubei Oilfield, the displacement performance of polymer surfactant is evaluated. Reasonable injection parameters and oil displacement effects after water flooding are also researched. Compared with conventional polymer with intermediate molecular weight, polymer surfactant has the properties of higher viscosity at low concentration condition and lower interfacial tension. Laboratory experiments indicate that the displacement effect of polymer surfactant is much better than that of conventional polymer at a slug size of 0.57 PV. The oil recovery of polymer surfactant increases by more than 10% after water flooding. Considering the actual situation of low-permeability of Pubei Oilfield reservoirs, the system viscosity of 30 mPa·s is chosen. The corresponding concentration of Type III polymer surfactant is 600 mg/L and the injected slug is 0.57 PV and the oil recovery can be increased by 11.69%.

  1. Determination of the interaction parameter and topological scaling features of symmetric star polymers in dilute solution

    KAUST Repository

    Rai, Durgesh K.

    2015-07-15

    Star polymers provide model architectures to understand the dynamic and rheological effects of chain confinement for a range of complex topological structures like branched polymers, colloids, and micelles. It is important to describe the structure of such macromolecular topologies using small-angle neutron and x-ray scattering to facilitate understanding of their structure-property relationships. Modeling of scattering from linear, Gaussian polymers, such as in the melt, has applied the random phase approximation using the Debye polymer scattering function. The Flory-Huggins interaction parameter can be obtained using neutron scattering by this method. Gaussian scaling no longer applies for more complicated chain topologies or when chains are in good solvents. For symmetric star polymers, chain scaling can differ from ν=0.5(df=2) due to excluded volume, steric interaction between arms, and enhanced density due to branching. Further, correlation between arms in a symmetric star leads to an interference term in the scattering function first described by Benoit for Gaussian chains. In this work, a scattering function is derived which accounts for interarm correlations in symmetric star polymers as well as the polymer-solvent interaction parameter for chains of arbitrary scaling dimension using a hybrid Unified scattering function. The approach is demonstrated for linear, four-arm and eight-arm polyisoprene stars in deuterated p-xylene.

  2. Physicochemical characterization of in situ drug-polymer nanocomplex formed between zwitterionic drug and ionomeric material in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Salamanca, Constain H., E-mail: chsalamanca@icesi.edu.co [Pharmaceutical physical chemistry laboratory, Department of Pharmacy, Faculty of Natural Sciences, ICESI University, Cali (Colombia); Castillo, Duvan F.; Villada, Juan D. [Pharmaceutical physical chemistry laboratory, Department of Pharmacy, Faculty of Natural Sciences, ICESI University, Cali (Colombia); Rivera, Gustavo R. [SIT Biotech GmbH, BMZ 2 Otto-Hahn-Str. 15, 44227 Dortmund (Germany)

    2017-03-01

    Biocompatible polymeric materials with the potential to form functional structures, in association with different therapeutic molecules, in physiological media, represent a great potential for biological and pharmaceutical applications. Therefore, here the formation of a nano-complex between a synthetic cationic polymer and model drug (ampicillin trihydrate) was studied. The formed complex was characterized by size and zeta potential measurements, using dynamic light scattering and capillary electrophoresis. Moreover, the chemical and thermodynamically stability of these complexes were studied. The ionomeric material, here referred as EuCl, was obtained by equimolar reaction between Eudragit E and HCl. The structural characterization was carried out by potentiometric titration, FTIR spectroscopy, and DSC. The effect of pH, time, polymer concentration and ampicillin/polymer molar ratio over the hydrodynamic diameter and zeta potential were established. The results show that EuCl ionomer in aqueous media presents two different populations of nanoparticles; one of this tends to form flocculated aggregates in high pH and concentrations, by acquiring different conformations in solution by changing from a compact to an extended conformation. Moreover, the formation of an in situ interfacial polymer-drug complex was demonstrated, this could slightly reduce the hydrolytic degradation of the drug while affecting its solubility, mainly under acidic conditions. - Highlights: • The EuCl ionomer in aqueous media presents two different populations of nanoparticle, corresponding to proximally 15 nm and 150 nm. • The EuCl ionomer in aqueous media may form different structure depending on the pH and polymer concentration, which tends to form flocculated aggregates in high pH and concentrations. • The formation of an in situ interfacial polymer-drug complex was demonstrated, which could slightly reduce the hydrolytic degradation of the drug and affecting its solubility in

  3. Imprinting of Phenylalanine ethyl ester in cyclodextrin polymers in aqueous solution

    DEFF Research Database (Denmark)

    Detcheva, Anna Hr.; Yu, Donghong; Larsen, Kim Lambertsen

    During the last decades there has been a wide interest of developing molecularly imprinted polymers, which selectively can recognize small molecules. Cyclodextrins offer relatively strong binding site of a wide range of small molecules in water and molecular imprinted polymers of these have...... previously been produced with some success. Nevertheless most molecules of interest for molecular imprinting are too samll to accommodate more than one cyclodextrin per molecule and thus limited selectivity may be expected. In order to improve the selectivity of cyclodextrin based molecular imprinted polymer...

  4. Thermoelectric Properties of Solution-Processed n-Doped Ladder-Type Conducting Polymers

    DEFF Research Database (Denmark)

    Wang, Suhao; Sun, Hengda; Ail, Ujwala

    2016-01-01

    Ladder-type "torsion-free" conducting polymers (e.g., polybenzimidazobenzophenanthroline (BBL)) can outperform "structurally distorted" donor-acceptor polymers (e.g., P(NDI2OD-T2)), in terms of conductivity and thermoelectric power factor. The polaron delocalization length is larger in BBL than...... in P(NDI2OD-T2), resulting in a higher measured polaron mobility. Structure-function relationships are drawn, setting material-design guidelines for the next generation of conducting thermoelectric polymers....

  5. Carrier Transport Enhancement in Conjugated Polymers through Interfacial Self-Assembly of Solution-State Aggregates

    KAUST Repository

    Zhao, Kui; Khan, Hadayat Ullah; Li, Ruipeng; Hu, Hanlin; Amassian, Aram

    2016-01-01

    and extension of the conjugated backbone of the polymer which clearly translate to significant improvements of carrier transport at the semiconductor-dielectric interface in organic thin film transistors. This study points to opportunities in combining

  6. Development of Novel Method for Rapid Extract of Radionuclides from Solution Using Polymer Ligand Film

    Science.gov (United States)

    Rim, Jung H.

    Accurate and fast determination of the activity of radionuclides in a sample is critical for nuclear forensics and emergency response. Radioanalytical techniques are well established for radionuclides measurement, however, they are slow and labor intensive, requiring extensive radiochemical separations and purification prior to analysis. With these limitations of current methods, there is great interest for a new technique to rapidly process samples. This dissertation describes a new analyte extraction medium called Polymer Ligand Film (PLF) developed to rapidly extract radionuclides. Polymer Ligand Film is a polymer medium with ligands incorporated in its matrix that selectively and rapidly extract analytes from a solution. The main focus of the new technique is to shorten and simplify the procedure necessary to chemically isolate radionuclides for determination by alpha spectrometry or beta counting. Five different ligands were tested for plutonium extraction: bis(2-ethylhexyl) methanediphosphonic acid (H2DEH[MDP]), di(2-ethyl hexyl) phosphoric acid (HDEHP), trialkyl methylammonium chloride (Aliquat-336), 4,4'(5')-di-t-butylcyclohexano 18-crown-6 (DtBuCH18C6), and 2-ethylhexyl 2-ethylhexylphosphonic acid (HEH[EHP]). The ligands that were effective for plutonium extraction further studied for uranium extraction. The plutonium recovery by PLFs has shown dependency on nitric acid concentration and ligand to total mass ratio. H2DEH[MDP] PLFs performed best with 1:10 and 1:20 ratio PLFs. 50.44% and 47.61% of plutonium were extracted on the surface of PLFs with 1M nitric acid for 1:10 and 1:20 PLF, respectively. HDEHP PLF provided the best combination of alpha spectroscopy resolution and plutonium recovery with 1:5 PLF when used with 0.1M nitric acid. The overall analyte recovery was lower than electrodeposited samples, which typically has recovery above 80%. However, PLF is designed to be a rapid field deployable screening technique and consistency is more important

  7. Unraveling the Solution-State Supramolecular Structures of Donor-Acceptor Polymers and their Influence on Solid-State Morphology and Charge-Transport Properties.

    Science.gov (United States)

    Zheng, Yu-Qing; Yao, Ze-Fan; Lei, Ting; Dou, Jin-Hu; Yang, Chi-Yuan; Zou, Lin; Meng, Xiangyi; Ma, Wei; Wang, Jie-Yu; Pei, Jian

    2017-11-01

    Polymer self-assembly in solution prior to film fabrication makes solution-state structures critical for their solid-state packing and optoelectronic properties. However, unraveling the solution-state supramolecular structures is challenging, not to mention establishing a clear relationship between the solution-state structure and the charge-transport properties in field-effect transistors. Here, for the first time, it is revealed that the thin-film morphology of a conjugated polymer inherits the features of its solution-state supramolecular structures. A "solution-state supramolecular structure control" strategy is proposed to increase the electron mobility of a benzodifurandione-based oligo(p-phenylene vinylene) (BDOPV)-based polymer. It is shown that the solution-state structures of the BDOPV-based conjugated polymer can be tuned such that it forms a 1D rod-like structure in good solvent and a 2D lamellar structure in poor solvent. By tuning the solution-state structure, films with high crystallinity and good interdomain connectivity are obtained. The electron mobility significantly increases from the original value of 1.8 to 3.2 cm 2 V -1 s -1 . This work demonstrates that "solution-state supramolecular structure" control is critical for understanding and optimization of the thin-film morphology and charge-transport properties of conjugated polymers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Reexamination of the Classical View of how Drag-Reducing Polymer Solutions Modify the Mean Velocity Profile: Baseline Results

    Science.gov (United States)

    Farsiani, Yasaman; Baade, Jacquelyne; Elbing, Brian

    2016-11-01

    Recent numerical and experimental data have shown that the classical view of how drag-reducing polymer solutions modify the mean turbulent velocity profile is incorrect. The classical view is that the log-region is unmodified from the traditional law-of-the-wall for Newtonian fluids, though shifted outward. Thus the current study reexamines the modified velocity distribution and its dependence on flow and polymer properties. Based on previous work it is expected that the behavior will depend on the Reynolds number, Weissenberg number, ratio of solvent viscosity to the zero-shear viscosity, and the ratio between the coiled and fully extended polymer chain lengths. The long-term objective for this study includes a parametric study to assess the velocity profile sensitivity to each of these parameters. This study will be performed using a custom design water tunnel, which has a test section that is 1 m long with a 15.2 cm square cross section and a nominal speed range of 1 to 10 m/s. The current presentation focuses on baseline (non-polymeric) measurements of the velocity distribution using PIV, which will be used for comparison of the polymer modified results. Preliminary polymeric results will also be presented. This work was supported by NSF Grant 1604978.

  9. Driving High-Performance n- and p-type Organic Transistors with Carbon Nanotube/Conjugated Polymer Composite Electrodes Patterned Directly from Solution

    KAUST Repository

    Hellstrom, Sondra L.; Jin, Run Zhi; Stoltenberg, Randall M.; Bao, Zhenan

    2010-01-01

    We report patterned deposition of carbon nanotube/conjugated polymer composites from solution with high nanotube densities and excellent feature resolution. Such composites are suited for use as electrodes in high-performance transistors

  10. Osmotic pressure and virial coefficients of star and comb polymer solutions: dissipative particle dynamics.

    Science.gov (United States)

    Wang, Tzu-Yu; Fang, Che-Ming; Sheng, Yu-Jane; Tsao, Heng-Kwong

    2009-03-28

    The effects of macromolecular architecture on the osmotic pressure pi and virial coefficients (B(2) and B(3)) of star and comb polymers in good solvents are studied by dissipative particle dynamics simulations for both dilute and semiconcentrated regimes. The dependence of the osmotic pressure on polymer concentration is directly calculated by considering two reservoirs separated by a semipermeable, fictitious membrane. Our simulation results show that the ratios A(n+1) identical with B(n+1)/R(g)(3n) are essentially constant and A(2) and A(3) are arm number (f) dependent, where R(g) is zero-density radius of gyration. The value of dimensionless virial ratio g = A(3)/A(2)(2) increases with arm number of stars whereas it is essentially arm number independent for comb polymers. In semiconcentrated regime the scaling relation between osmotic pressure and volume fraction, pi proportional to phi(lambda), still holds for both star and comb polymers. For comb polymers, the exponent lambda is close to lambda(*) (approximately = 2.73 for linear chains) and is independent of the arm number. However, for star polymers, the exponent lambda deviates from lambda(*) and actually grows with increasing the arm number. This may be attributed to the significant ternary interactions near the star core in the many-arm systems.

  11. All-Solution-Processed, Ambient Method for ITO-Free, Roll-Coated Tandem Polymer Solar Cells using Solution- Processed Metal Films

    DEFF Research Database (Denmark)

    Angmo, Dechan; Dam, Henrik Friis; Andersen, Thomas Rieks

    2014-01-01

    A solution-processed silver film is employed in the processing of top-illuminated indium-tin-oxide (ITO)-free polymer solar cells in single- and double-junction (tandem) structures. The nontransparent silver film fully covers the substrate and serves as the bottom electrode whereas a PEDOT...... in terms of surface morphological and topographical properties and to ITO in terms of flexibility. The slot–die coated Ag film demonstrates extremely low roughness (a root-meansquare roughness of 3 nm was measured over 240_320 mm2 area), is highly conductive (

  12. Solution-Processed Donor-Acceptor Polymer Nanowire Network Semiconductors For High-Performance Field-Effect Transistors

    Science.gov (United States)

    Lei, Yanlian; Deng, Ping; Li, Jun; Lin, Ming; Zhu, Furong; Ng, Tsz-Wai; Lee, Chun-Sing; Ong, Beng S.

    2016-01-01

    Organic field-effect transistors (OFETs) represent a low-cost transistor technology for creating next-generation large-area, flexible and ultra-low-cost electronics. Conjugated electron donor-acceptor (D-A) polymers have surfaced as ideal channel semiconductor candidates for OFETs. However, high-molecular weight (MW) D-A polymer semiconductors, which offer high field-effect mobility, generally suffer from processing complications due to limited solubility. Conversely, the readily soluble, low-MW D-A polymers give low mobility. We report herein a facile solution process which transformed a lower-MW, low-mobility diketopyrrolopyrrole-dithienylthieno[3,2-b]thiophene (I) into a high crystalline order and high-mobility semiconductor for OFETs applications. The process involved solution fabrication of a channel semiconductor film from a lower-MW (I) and polystyrene blends. With the help of cooperative shifting motion of polystyrene chain segments, (I) readily self-assembled and crystallized out in the polystyrene matrix as an interpenetrating, nanowire semiconductor network, providing significantly enhanced mobility (over 8 cm2V−1s−1), on/off ratio (107), and other desirable field-effect properties that meet impactful OFET application requirements. PMID:27091315

  13. Photoluminescence Spectroscopy of Rhodamine 800 Aqueous Solution and Dye-Doped Polymer Thin-Film: Concentration and Solvent Effects

    Science.gov (United States)

    Le, Khai Q.; Dang, Ngo Hai

    2018-05-01

    This paper investigates solvent and concentration effects on photoluminescence (PL) or fluorescence properties of Rhodamine 800 (Rho800) dyes formed in aqueous solution and polymer thin-film. Various commonly used organic solvents including ethanol, methanol and cyclopentanol were studied at a constant dye concentration. There were small changes in the PL spectra for the different solvents in terms of PL intensity and peak wavelength. The highest PL intensity was observed for cyclopentanol and the lowest for ethanol. The longest peak wavelength was found in cyclopentanol (716 nm) and the shortest in methanol (708 nm). Dissolving the dye powder in the methanol solvent and varying the dye concentration in aqueous solution from the high concentrated solution to highly dilute states, the wavelength tunability was observed between about 700 nm in the dilute state and 730 nm at high concentration. Such a large shift may be attributed to the formation of dye aggregates. Rho800 dye-doped polyvinyl alcohol (PVA) polymer thin-film was further investigated. The PL intensity of the dye in the form of thin-film is lower than that of the aqueous solution form whereas the peak wavelength is redshifted due to the presence of PVA. This paper, to our best knowledge, reports the first study of spectroscopic properties of Rho800 dyes in various forms and provides useful guidelines for production of controllable organic luminescence sources.

  14. The processing of CdSe/Polymer nanocomposites via solution organometallic chemistry

    International Nuclear Information System (INIS)

    Khanna, P.K.; Singh, Narendra; Charan, Shobhit; Lonkar, Sunil P.; Reddy, A. Satyanarayana; Patil, Yogesh; Viswanath, A. Kasi

    2006-01-01

    This paper presents in situ preparation of CdSe nanoparticles using poly(vinyl alcohol) [PVA] and polymethylmethacrylate [PMMA] as matrices by use of organoselenium compound. Reaction of cadmium metal salt and 1,2,3-selenadiazole (the source of selenium) enabled formation of CdSe nanoparticles. Use of selenadiazole in the present work with polymer is first of its kind. The radical polymerization of methycrylate monomer with benzoyl peroxide followed by reaction of respective reagents have been successfully employed to synthesize CdSe/PMMA nanocomposite. Similarly, reaction between selenadiazole and cadmium metal salt in aq. PVA yielded polymer coated or mixed CdSe nanoparticles. The UV-vis absorption spectra showed blue shift of about 200 nm with respect to band-gap energy of bulk CdSe, due to size quantization effect in CdSe particles. An emission band was observed at 530 nm in photoluminescence spectrum (PL) of CdSe/PMMA. IR spectra indicated shifts in the values of the polymer functional group due to nanoparticles. X-ray measurement of CdSe/Polymer nano-composites showed broad pattern for cubic CdSe and particle size of CdSe was estimated to be <10 nm. TGA revealed gradual weight loss between 200 and 400 deg. C indicating increased thermal stability of the polymer

  15. Radiation amorphization of materials

    International Nuclear Information System (INIS)

    Neklyudov, I.M.; Chernyaeva, T.P.

    1993-01-01

    The results of experimental and theoretical research on radiation amorphization are presented in this analytical review. Mechanism and driving forces of radiation amorphization are described, kinetic and thermodynamic conditions of amorphization are formulated. Compositional criteria of radiation amorphization are presented, that allow to predict irradiation behaviour of materials, their tendency to radiation amorphization. Mechanism of transition from crystalline state to amorphous state are considered depending on dose, temperature, structure of primary radiation damage and flux level. (author). 134 refs., 4 tab., 25 fig

  16. Pyramid shape of polymer solar cells: a simple solution to triple efficiency

    International Nuclear Information System (INIS)

    Xia, Yuxin; Hou, Lintao; Ma, Kaijie; Wang, Biao; Xiong, Kang; Liu, Pengyi; Liao, Jihai; Wen, Shangsheng; Wang, Ergang

    2013-01-01

    Pyramid-shaped polymer solar cells fabricated on flexible substrates were investigated. Effective light trapping can be realized due to light reflection in all 360° directions, and 100% space utilization is achieved when assembled into arrays. The power conversion efficiency is enhanced by 200% ([60]PCBM as the acceptor) and 260% ([70]PCBM as the acceptor) with a dihedral angle of 30° between the opposite sides of the pyramid compared with a planar device, and a high V oc of 3.5 V in series connection is obtained. Considering the material utilization, an angle of 90° for pyramid-shaped polymer solar cells is proposed. Pyramid-shaped polymer solar cells are particularly suitable for installation on roof of vehicles and houses, which have limited surface area. (paper)

  17. Corrosion at the Polymer-Metal Interface in Artificial Seawater Solutions

    Directory of Open Access Journals (Sweden)

    Amelia M. Anderson-Wile

    2012-01-01

    Full Text Available Polymer components for liquid sealing applications are employed in a variety of potentially corrosive environments, such as seawater. Frequently, corrosion of the metal is found at or adjacent to the rubber-metal interface rather than at a noncontact area. The corrosion of different metal alloys (titanium, bronze, nickel, aluminum, 316 stainless steel, and 4130 steel in combination with rubber O-rings (Buna-N and EPDM of varying internal diameters and cross-sectional shapes in seawater over a period of four years is described herein. The corrosion of some metals (i.e., 4130 stainless steel was found to be accelerated through interaction with Buna-N rubber O-rings. Theories to account for corrosion at the polymer-metal interface, especially with respect to polymer composition and O-ring size and shape, are discussed.

  18. A New Methodology to Select the Preferred Solutions from the Pareto-optimal Set: Application to Polymer Extrusion

    International Nuclear Information System (INIS)

    Ferreira, Jose C.; Gaspar-Cunha, Antonio; Fonseca, Carlos M.

    2007-01-01

    Most of the real world optimization problems involve multiple, usually conflicting, optimization criteria. Generating Pareto optimal solutions plays an important role in multi-objective optimization, and the problem is considered to be solved when the Pareto optimal set is found, i.e., the set of non-dominated solutions. Multi-Objective Evolutionary Algorithms based on the principle of Pareto optimality are designed to produce the complete set of non-dominated solutions. However, this is not allays enough since the aim is not only to know the Pareto set but, also, to obtain one solution from this Pareto set. Thus, the definition of a methodology able to select a single solution from the set of non-dominated solutions (or a region of the Pareto frontier), and taking into account the preferences of a Decision Maker (DM), is necessary. A different method, based on a weighted stress function, is proposed. It is able to integrate the user's preferences in order to find the best region of the Pareto frontier accordingly with these preferences. This method was tested on some benchmark test problems, with two and three criteria, and on a polymer extrusion problem. This methodology is able to select efficiently the best Pareto-frontier region for the specified relative importance of the criteria

  19. Block copolymer micelle coronas as quasi-two-dimensional dilute or semidilute polymer solutions

    DEFF Research Database (Denmark)

    Svaneborg, C.; Pedersen, J.S.

    2001-01-01

    Chain-chain interactions in a corona of polymers tethered to a spherical core under good solvent conditions are studied using Monte Carlo simulations. The total scattering function of the corona as well as different partial contributions are sampled. By combining the different contributions...

  20. A simple relation for the concentration dependence of osmotic pressure and depletion thickness in polymer solutions

    NARCIS (Netherlands)

    Fleer, G.J.; Skvortsov, A.M.; Tuinier, R.

    2007-01-01

    We propose simple expressions II/IIo = 1 + and (omega/omega(ex))(3 alpha-1) and (delta(0)/delta)(2) = 1 + (omega/omega(ex))(2 alpha) for the osmotic pressure II and the depletion thickness 6 as a function of the polymer concentration omega. Here, IIo and delta 0 correspond to the dilute limit, and

  1. Boosting the ambipolar performance of solution-processable polymer semiconductors via hybrid side-chain engineering.

    Science.gov (United States)

    Lee, Junghoon; Han, A-Reum; Yu, Hojeong; Shin, Tae Joo; Yang, Changduk; Oh, Joon Hak

    2013-06-26

    Ambipolar polymer semiconductors are highly suited for use in flexible, printable, and large-area electronics as they exhibit both n-type (electron-transporting) and p-type (hole-transporting) operations within a single layer. This allows for cost-effective fabrication of complementary circuits with high noise immunity and operational stability. Currently, the performance of ambipolar polymer semiconductors lags behind that of their unipolar counterparts. Here, we report on the side-chain engineering of conjugated, alternating electron donor-acceptor (D-A) polymers using diketopyrrolopyrrole-selenophene copolymers with hybrid siloxane-solubilizing groups (PTDPPSe-Si) to enhance ambipolar performance. The alkyl spacer length of the hybrid side chains was systematically tuned to boost ambipolar performance. The optimized three-dimensional (3-D) charge transport of PTDPPSe-Si with pentyl spacers yielded unprecedentedly high hole and electron mobilities of 8.84 and 4.34 cm(2) V(-1) s(-1), respectively. These results provide guidelines for the molecular design of semiconducting polymers with hybrid side chains.

  2. Photostability of solutions of rare earth chelates in organic solvents and polymers

    International Nuclear Information System (INIS)

    Karasev, V.E.; Mirochnik, A.G.; Lysun, T.V.; Vovna, V.I.

    1990-01-01

    Consideration is given to results of comparative study of photochemical properties of rare erath chelate complexes (adducts of rare earth β-diketonates with triphenylphosphine oxide, hexamethylphosphotriamide, phenanthroline) in organic solvents and polymers. Effect of excitation conditions, composition, solvent, nature of ligand and rare earth ion on photolysis rate was investigated. 9 refs.; 2 figs.; 4 tabs

  3. Rate of Pu(IV) polymer formation in nitric acid solutions. A parametric study

    Energy Technology Data Exchange (ETDEWEB)

    Toth, L.M.; Osborne, M.M.

    1984-07-01

    The kinetics of Pu(IV) polymer formation has been examined with the intent of developing a simple mathematical equation that would predict the appearance of polymer. The fundamental polymerization rate has been found to be dependent on [Pu(IV)]{sup 1} {sup 2} and [HNO{sub 3}]{sup -6}. The activation energy for polymer formation is real temperature dependent, varying from 66.9 kJ/mol (16 kcal/mol) at 25{sup 0}C to 150.5 kJ/mol (36 kcal/mol) at 105{sup 0}C. These relationships have guided the developement of an empirical model that gives time to form 2% polymer in hours, t = [Pu/sub T/]/sup a/[HNO{sub 3}]/sup b/ Ae/sup c/T/, where a = -1.6, b = 4.6, c = 12.300 K, and A = 7.66 x 10{sup -16} h M{sup -3}; [Pu/sub T/] is the total plutonium concentration, mol/L; and [HNO{sub 3}] is the makeup nitric acid concentration, mol/L. 11 references, 26 figures, 1 table.

  4. Improvement of mechanical properties of hydrogel by irradiation of polymers in aqueous solution with κ-carrageenan

    International Nuclear Information System (INIS)

    Makuuchi, K.; Yoshii, F.; Zhai, M.

    2000-01-01

    Predominate radiation reaction of κ-carrageenan (KC) hydrogel is the main chain scission of KC. The gel strength of KC hydrogel decreased with increasing irradiation dose. However, KC was found to enhances the radiation crosslinking of synthetic water-soluble polymer (SWSP) such as poly(ethylene oxide) (PEO) and poly(N-vinylpyrolidone) (PVP) in aqueous solution. The gel strength of SWSP hydrogel increased with increasing dose when KC was blended. Probably the radiation degraded KC radicals are recombined with radicals of PVP and PEO. The hydrogel thus prepared absorbs huge amounts of water due to the presence of strong hydrophilic -OSO 3 - groups in KC. (author)

  5. Improvement of mechanical properties of hydrogel by irradiation of polymers in aqueous solution with {kappa}-carrageenan

    Energy Technology Data Exchange (ETDEWEB)

    Makuuchi, K.; Yoshii, F. [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Aranilla, C.T. [Philippine Nuclear Research Institute, Diliman, Quezon (Philippines); Zhai, M. [Department of Technical Physics, Peking Univ., Beijing (China)

    2000-03-01

    Predominate radiation reaction of {kappa}-carrageenan (KC) hydrogel is the main chain scission of KC. The gel strength of KC hydrogel decreased with increasing irradiation dose. However, KC was found to enhances the radiation crosslinking of synthetic water-soluble polymer (SWSP) such as poly(ethylene oxide) (PEO) and poly(N-vinylpyrolidone) (PVP) in aqueous solution. The gel strength of SWSP hydrogel increased with increasing dose when KC was blended. Probably the radiation degraded KC radicals are recombined with radicals of PVP and PEO. The hydrogel thus prepared absorbs huge amounts of water due to the presence of strong hydrophilic -OSO{sub 3}{sup -} groups in KC. (author)

  6. Gelatin Nano-coating for Inhibiting Surface Crystallization of Amorphous Drugs.

    Science.gov (United States)

    Teerakapibal, Rattavut; Gui, Yue; Yu, Lian

    2018-01-05

    Inhibit the fast surface crystallization of amorphous drugs with gelatin nano-coatings. The free surface of amorphous films of indomethacin or nifedipine was coated by a gelatin solution (type A or B) and dried. The coating's effect on surface crystallization was evaluated. Coating thickness was estimated from mass change after coating. For indomethacin (weak acid, pK a  = 4.5), a gelatin coating of either type deposited at pH 5 and 10 inhibited its fast surface crystal growth. The coating thickness was 20 ± 10 nm. A gelatin coating deposited at pH 3, however, provided no protective effect. These results suggest that an effective gelatin coating does not require that the drug and the polymer have opposite charges. The ineffective pH 3 coating might reflect the poor wetting of indomethacin's neutral, hydrophobic surface by the coating solution. For nifedipine (weak base, pK a  = 2.6), a gelatin coating of either type deposited at pH 5 inhibited its fast surface crystal growth. Gelatin nano-coatings can be conveniently applied to amorphous drugs from solution to inhibit fast surface crystallization. Unlike strong polyelectrolyte coatings, a protective gelatin coating does not require strict pairing of opposite charges. This could make gelatin coating a versatile, pharmaceutically acceptable coating for stabilizing amorphous drugs.

  7. Effect of micro-environment modification and polymer type on the in-vitro dissolution behavior and in-vivo performance of amorphous solid dispersions.

    Science.gov (United States)

    Sun, Weiwei; Pan, Baoliang

    2017-06-15

    This study investigates the effects of micro-environment modification and polymer type on the in-vitro dissolution behavior and in-vivo performance of micro-environment pH modifying solid dispersions (pH M -SD) for the poorly water-soluble model drug Toltrazuril (TOL). Various pH M -SDs were prepared using Ca(OH) 2 as a pH-modifier in hydrophilic polymers, including polyethylene glycol 6000 (PEG6000), polyvinylpyrrolidone k30 (PVPk30) and hydroxypropyl methylcellulose (HPMC). Based on the results of physicochemical characterizations and in-vitro dissolution testing, the representative ternary (Ca(OH) 2 :TOL:PEG6000/HPMC/PVPk30=1:8:24, w/w/w) and binary (TOL:PVPk30=1:3, w/w) solid dispersions were selected and optimized to perform in-vivo pharmacokinetic study. The micro-environment pH modification improved the in-vitro water-solubility and in-vivo bioavailability of parent drug TOL. Furthermore, the addition of alkalizers not only enhanced the release and absorption of prototype drug, but also promoted the generation of active metabolites, including toltrazuril sulfoxide (TOLSO) and toltrazuril sulfone (TOLSO 2 ). The in-vitro dissolution profiles and in-vivo absorption, distribution and metabolism behaviors of the pH M -SDs varied with polymer type. Moreover, in-vivo bioavailability of three active pharmaceutical ingredients increased with an increase in in-vitro dissolution rates of the drug from the pH M -SDs prepared with various polymers. Therefore, a non-sink in-vitro dissolution method can be used to predict the in-vivo performance of pH M -SDs formulated with various polymers with trend consistency. In-vitro and in-vivo screening procedures revealed that the pH M -SD composed of Ca(OH) 2 , TOL and PVPk30 at a weight ratio of 1:8:24, of which the safety was adequately proved via histopathological examination, may be a promising candidate for providing better clinical outcomes. Copyright © 2017. Published by Elsevier B.V.

  8. Calculation of amorphous silica solubilities at 25° to 300°C and apparent cation hydration numbers in aqueous salt solutions using the concept of effective density of water

    Science.gov (United States)

    Fournier, Robert O.; Williams, Marshall L.

    1983-01-01

    The solubility of amorphous silica in aqueous salt solutions at 25° to 300°C can be calculated using information on its solubility in pure water and a model in which the activity of water in the salt solution is defined to equal the effective density. pe, of “free” water in that solution. At temperatures of 100°C and above, pe closely equals the product of the density of the solution times the weight fraction of water in the solution. At 25°C, a correction parameter must be applied to pe that incorporates a term called the apparent cation hydration number, h. Because of the many assumptions and other uncertainties involved in determining values of h, by the model used here, the reported numbers are not necessarily real hydration numbers even though they do agree with some published values determined by activity and diffusion methods. Whether or not h is a real hydration number, it would appear to be useful in its inclusion within a more extensive activity coefficient term that describes the departure of silica solubilities in concentrated salt solutions from expected behavior according to the model presented here. Values of h can be calculated from measured amorphous silica solubilities in salt solutions at 25°C provided there is no complexing of dissolved silica with the dissolved salt, or if the degree of complexing is known. The previously postulated aqueous silica-sulfate complexing in aqueous Na2SO4 solutions is supported by results of the present effective density of water model

  9. Impact of polymer type on bioperformance and physical stability of hot melt extruded formulations of a poorly water soluble drug.

    Science.gov (United States)

    Mitra, Amitava; Li, Li; Marsac, Patrick; Marks, Brian; Liu, Zhen; Brown, Chad

    2016-05-30

    Amorphous solid dispersion formulations have been widely used to enhance bioavailability of poorly soluble drugs. In these formulations, polymer is included to physically stabilize the amorphous drug by dispersing it in the polymeric carrier and thus forming a solid solution. The polymer can also maintain supersaturation and promote speciation during dissolution, thus enabling better absorption as compared to crystalline drug substance. In this paper, we report the use of hot melt extrusion (HME) to develop amorphous formulations of a poorly soluble compound (FaSSIF solubility=1μg/mL). The poor solubility of the compound and high dose (300mg) necessitated the use of amorphous formulation to achieve adequate bioperformance. The effect of using three different polymers (HPMCAS-HF, HPMCAS-LF and copovidone), on the dissolution, physical stability, and bioperformance of the formulations was demonstrated. In this particular case, HPMCAS-HF containing HME provided the highest bioavailability and also had better physical stability as compared to extrudates using HPMCAS-LF and copovidone. The data demonstrated that the polymer type can have significant impact on the formulation bioperformance and physical stability. Thus a thorough understanding of the polymer choice is imperative when designing an amorphous solid dispersion formulation, such that the formulation provides robust bioperformance and has adequate shelf life. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Removal of Cr(VI and Toxic Ions from Aqueous Solutions and Tannery Wastewater Using Polymer-Clay Composites

    Directory of Open Access Journals (Sweden)

    Abd El-Azeem Sallam

    2017-10-01

    Full Text Available Polymer-clay composites were prepared by natural zeolite (clinoptilolite or naturally local clay deposits in an N,N-methylene-bis-acrylamide as cross-linked. The resultant composites were used for the removal of Cr(VI from an aqueous solution. Additionally, their effects on soluble ions of tannery wastewater were investigated. The produced composites were characterized using X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR, and scanning electron microscopy (SEM. The results showed that Cr(VI removal is dependent upon initial concentrations and pH. The adsorption quantity of Cr(VI onto the polymerized clay deposit followed by polymerized zeolite exhibited higher values than their original samples. The polymer-clay composite of clay deposit showed the highest removal of 76.3–100% overall initial concentrations of 10–50 mg L−1 and at initial pH of 2. Kinetics of Cr(VI removal by various sorbents was predicted using a pseudo–second order model. Our findings showed that the levels of salinity and various soluble ions (Cr2+, Na+, Cl− and SO42− in tannery wastewater are very high, and their levels were reduced after treatment, especially by polymerized sorbents. It could be concluded that the polymer-clay composites may be employed as a highly efficient sorbent for the removal of Cr(VI and toxic ions from the wastewater.

  11. Solution-processable MoOx nanocrystals enable highly efficient reflective and semitransparent polymer solar cells

    KAUST Repository

    Jagadamma, Lethy Krishnan; Hu, Hanlin; Kim, Taesoo; Ngongang Ndjawa, Guy Olivier; Mansour, Ahmed; El Labban, Abdulrahman; Faria, Jorge C.D.; Munir, Rahim; Anjum, Dalaver H.; McLachlan, Martyn A.; Amassian, Aram

    2016-01-01

    Solution-manufacturing of organic solar cells with best-in-class power conversion efficiency (PCE) will require all layers to be solution-coated without compromising solar cell performance. To date, the hole transporting layer (HTL) deposited on top

  12. Modeling of the branching influence on liquid–liquid equilibrium of binary and ternary polymer solutions by lattice–cluster theory

    International Nuclear Information System (INIS)

    Browarzik, Dieter; Langenbach, Kai; Enders, Sabine; Browarzik, Christina

    2013-01-01

    Highlights: ► Liquid–liquid equilibrium (LLE) is calculated with the lattice–cluster theory (LCT). ► Equations of the LCT are reduced to only three geometrical parameters. ► Branching influence on the LLE is modeled for binary and ternary polymer solutions. ► Branched and linear solvents and polymers are compared in their influence on LLE. ► Solutions of branched polymers in branched solvents show the best miscibility. -- Abstract: The liquid–liquid equilibrium (LLE) of ternary model systems of the type solvent A + polymer B + solvent C is treated in the framework of lattice–cluster theory (LCT). There are a linear and a branched type of A-molecules as well as a linear and two types of strongly branched polymer molecules. The C-molecules are assumed to occupy only one lattice site. For nine binary and six ternary polymer solutions the branching influence on LLE is discussed. Currently, the LCT is the most useful model to take the architecture of the molecules into account. However, particularly for ternary systems the model is not comfortable because of the very numerous terms of the Gibbs energy. Using some relationships between the geometrical parameters of the model a considerable simplification is possible. In this paper the new and simpler equations of the LCT are presented. For comparison with experimental data critical temperatures of solutions of linear and branched polyethylene samples in diphenyl ether are calculated

  13. A corrosion-protective coating based on a solution-processable polymer-grafted graphene oxide nanocomposite

    International Nuclear Information System (INIS)

    Qi, Kai; Sun, Yimin; Duan, Hongwei; Guo, Xingpeng

    2015-01-01

    Highlights: • Solution-processable polymer-grafted graphene nanocomposite is synthesized. • The nanocomposite exhibits synergistic properties of both building blocks. • The nanocomposite can be easily applied to form a protective coating on metals. • The coating can effectively prevent corrosion of copper substrate. - Abstract: A new type of solution-processable graphene coating has been synthesized by grafting polymethylmethacrylate (PMMA) brushes on graphene oxide (GO) via surface-initiated atom transfer radical polymerization (ATRP). One major finding is that the PMMA-grafted GO nanocomposite exhibits synergistic properties of both building blocks, i.e., permeation inhibition of GO and solubility of PMMA in a variety of solvents, which makes it compatible with commonly used coating methods to form uniform coatings with controlled thickness. Our results demonstrate that PMMA-grafted GO coating can effectively block charge transfer at the metal–electrolyte interface and prevent corrosion of the copper substrate under aggressive saline conditions

  14. Stable Inverted Low-Bandgap Polymer Solar Cells with Aqueous Solution Processed Low-Temperature ZnO Buffer Layers

    Directory of Open Access Journals (Sweden)

    Chunfu Zhang

    2016-01-01

    Full Text Available Efficient inverted low-bandgap polymer solar cells with an aqueous solution processed low-temperature ZnO buffer layer have been investigated. The low-bandgap material PTB-7 is employed so that more solar light can be efficiently harvested, and the aqueous solution processed ZnO electron transport buffer layer is prepared at 150°C so that it can be compatible with the roll-to-roll process. Power conversion efficiency (PCE of the inverted device reaches 7.12%, which is near the control conventional device. More importantly, the inverted device shows a better stability, keeping more than 90% of its original PCE after being stored for 625 hours, while PCE of the conventional device is only 75% of what it was. In addition, it is found that the ZnO thin film annealed in N2 can obviously increase PCE of the inverted device further to 7.26%.

  15. Emission characteristics in solution-processed asymmetric white alternating current field-induced polymer electroluminescent devices

    Science.gov (United States)

    Chen, Yonghua; Xia, Yingdong; Smith, Gregory M.; Gu, Yu; Yang, Chuluo; Carroll, David L.

    2013-01-01

    In this work, the emission characteristics of a blue fluorophor poly(9, 9-dioctylfluorene) (PFO) combined with a red emitting dye: Bis(2-methyl-dibenzo[f,h]quinoxaline)(acetylacetonate)iridium (III) [Ir(MDQ)2(acac)], are examined in two different asymmetric white alternating current field-induced polymer electroluminescent (FIPEL) device structures. The first is a top-contact device in which the triplet transfer is observed resulting in the concentration-dependence of the emission similar to the standard organic light-emitting diode (OLED) structure. The second is a bottom-contact device which, however, exhibits concentration-independence of emission. Specifically, both dye emission and polymer emission are found for the concentrations as high as 10% by weight of the dye in the emitter. We attribute this to the significant different carrier injection characteristics of the two FIPEL devices. Our results suggest a simple and easy way to realize high-quality white emission.

  16. A New Property of Conjugated Polymer PFP: Catalytic Degradation of Methylene Blue Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A new property of conjugated polymer poly(furancarbinol-co-phenol)(PFP) was studied.The target copolymer was used as a catalyst after proper heating treatment. And dye methylene blue (MB) could be fully degraded and largely mineralized on PFP, under natural light or even in dark, in a few minutes. Furthermore, the catalytic activity could be preserved after several runs and the catalyst was readily separated. The effect of calcination temperature was also observed.

  17. On the origin of brittle fracture of entangled polymer solutions and melts

    DEFF Research Database (Denmark)

    Wagner, Manfred H.; Narimissa, Esmaeil; Huang, Qian

    2018-01-01

    A novel criterion for brittle fracture of entangled polymer liquids is presented: Crack initiation follows from rupture of primary C-C bonds, when the strain energy of an entanglement segment reaches the energy of the covalent bond. Thermal fluctuations lead to a short-time concentration...... of the strain energy on one C-C bond of the entanglement segment, and the chain ruptures. This limits the maximum achievable stretch of entanglement segments to a critical stretch of f(c)...

  18. Long Range Polymer Chain Dynamics of Highly Flexible Polysiloxane in Solution Probed by Pyrene Excimer Fluorescence

    Directory of Open Access Journals (Sweden)

    Janine L. Thoma

    2018-03-01

    Full Text Available A poly(dimethylsiloxane-co-(3-aminopropylmethylsiloxane polymer (PDMS with 20.3 mol % of (3-aminopropylmethyl siloxane monomer has been labeled randomly with 1-pyreneacetyl groups to generate a series of polysiloxanes (Py-PDMS with pyrenyl contents ranging from 0.7 mol % to 5.2 mol % of the total number of structural units. The remainder of the amino groups were acetylated to avoid intra-chain quenching of the excited singlet states of pyrene via exciplex formation with free amino groups while allowing the formation of excimers to proceed. The fluorescence spectra and temporal decays of the Py-PDMS samples were acquired in tetrahydrofuran (THF, N,N-dimethylformamide (DMF, and dioxane. blob, the average rate constant for intra-chain pyrene excimer formation, was determined from the analysis of the fluorescence decays. blob was found to equal 1.16 (±0.13 × 109, 1.14 (±0.12 × 109, and 0.99 (±0.10 × 109 s−1 in THF, DMF, and dioxane, respectively, at room temperature. They are the largest values found to date for any polymeric backbone in these solvents. The qualitative relationship found here between blob and the chemical structures of the polymers indicates that the luminescence characteristics of randomly labeled polymers is a very useful method to probe the long range dynamics of chains of almost any polymer that is amenable to substitution by a lumophore.

  19. Trap Healing for High-Performance Low-Voltage Polymer Transistors and Solution-Based Analog Amplifiers on Foil.

    Science.gov (United States)

    Pecunia, Vincenzo; Nikolka, Mark; Sou, Antony; Nasrallah, Iyad; Amin, Atefeh Y; McCulloch, Iain; Sirringhaus, Henning

    2017-06-01

    Solution-processed semiconductors such as conjugated polymers have great potential in large-area electronics. While extremely appealing due to their low-temperature and high-throughput deposition methods, their integration in high-performance circuits has been difficult. An important remaining challenge is the achievement of low-voltage circuit operation. The present study focuses on state-of-the-art polymer thin-film transistors based on poly(indacenodithiophene-benzothiadiazole) and shows that the general paradigm for low-voltage operation via an enhanced gate-to-channel capacitive coupling is unable to deliver high-performance device behavior. The order-of-magnitude longitudinal-field reduction demanded by low-voltage operation plays a fundamental role, enabling bulk trapping and leading to compromised contact properties. A trap-reduction technique based on small molecule additives, however, is capable of overcoming this effect, allowing low-voltage high-mobility operation. This approach is readily applicable to low-voltage circuit integration, as this work exemplifies by demonstrating high-performance analog differential amplifiers operating at a battery-compatible power supply voltage of 5 V with power dissipation of 11 µW, and attaining a voltage gain above 60 dB at a power supply voltage below 8 V. These findings constitute an important milestone in realizing low-voltage polymer transistors for solution-based analog electronics that meets performance and power-dissipation requirements for a range of battery-powered smart-sensing applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Scaling exponent and dispersity of polymers in solution by diffusion NMR.

    Science.gov (United States)

    Williamson, Nathan H; Röding, Magnus; Miklavcic, Stanley J; Nydén, Magnus

    2017-05-01

    Molecular mass distribution measurements by pulsed gradient spin echo nuclear magnetic resonance (PGSE NMR) spectroscopy currently require prior knowledge of scaling parameters to convert from polymer self-diffusion coefficient to molecular mass. Reversing the problem, we utilize the scaling relation as prior knowledge to uncover the scaling exponent from within the PGSE data. Thus, the scaling exponent-a measure of polymer conformation and solvent quality-and the dispersity (M w /M n ) are obtainable from one simple PGSE experiment. The method utilizes constraints and parametric distribution models in a two-step fitting routine involving first the mass-weighted signal and second the number-weighted signal. The method is developed using lognormal and gamma distribution models and tested on experimental PGSE attenuation of the terminal methylene signal and on the sum of all methylene signals of polyethylene glycol in D 2 O. Scaling exponent and dispersity estimates agree with known values in the majority of instances, leading to the potential application of the method to polymers for which characterization is not possible with alternative techniques. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. A new model and extension of Wong-Sandler mixing rule for prediction of (vapour + liquid) equilibrium of polymer solutions using EOS/GE

    International Nuclear Information System (INIS)

    Haghtalab, Ali; Espanani, Reza

    2004-01-01

    The cubic equation of state (CEOS) is a powerful method for calculation of (vapour + liquid) equilibrium (VLE) in polymer solutions. Using CEOS for both the vapour and liquid phases allows one to calculate the non-ideality of polymer solutions based on a single EOS approach. However, the traditional mixing rules are not appropriate to extend the CEOS to non-ideal mixtures such as polymer solutions. Several authors have applied the EOS/G E approach to predict (vapour + liquid) equilibria in polymer solutions, however, incorporating an appropriate excess Gibbs free energy for the new mixing rule is a major step. In this research, the NRTL-NRF model was extended in terms of volume fraction of polymer and solvent (instead of mole fraction), then equilibrium calculations were carried out using PRSV EOS and Wong-Sandler mixing rules. Using the adjustable parameters as a function of solution temperature, the NRTL-NRF model can be used as a predictive model. In comparison with NRTL model, the results of the new NRTL-NRF model show better accuracy

  2. Influence of Carrier (Polymer Type and Drug-Carrier Ratio in the Development of Amorphous Dispersions for Solubility and Permeability Enhancement of Ritonavir

    Directory of Open Access Journals (Sweden)

    Vivek S. Dave

    2017-09-01

    Full Text Available The influence of the ratio of Eudragit® L100-55 or Kolliphor® P188 on the solubility, dissolution, and permeability of ritonavir was studied with a goal of preparing solid dispersions (SDs of ritonavir. SDs were formulated using solvent evaporation or lyophilization techniques, and evaluated for their physical-chemical properties. The dissolution and permeability assessments of the functionality of the SDs were carried out. The preliminary functional stability of these formulations was assessed at accelerated storage conditions for a period of six months. Ritonavir: Eudragit® L100-55 (RE, 1:3 SD showed a 36-fold higher ritonavir solubility compared to pure ritonavir. Similarly, ritonavir: Kolliphor® P188 (RP, 1:2 SD exhibited a 49-fold higher ritonavir solubility compared to pure ritonavir. Ritonavir dissolution from RE formulations increased with increasing ratios of Eudragit® L100-55, up to a ritonavir: carrier ratio of 1:3. The ritonavir dissolution from RP formulations was highest at ritonavir: Kolliphor® P188 ratio of 1:2. Dissolution efficiencies of these formulations were found to be in line with, and supported the dissolution results. The permeability of ritonavir across the biological membrane from the optimized formulations RE (1:3 and RP (1:2 were ~76 % and ~97 %, respectively; and were significantly higher compared to that of pure ritonavir (~20 %. A preliminary (six-month stability study demonstrated the functional stability of prepared solid dispersions. The present study demonstrates that ritonavir solubility, dissolution, and permeability improvement can be achieved with a careful choice of the carrier polymer, and optimizing the amount of polymer in a SD formulation.

  3. Spray-dried HPMC microparticles of Indomethacin: Impact of drug-polymer ratio and viscosity of the polymeric solution on dissolution

    International Nuclear Information System (INIS)

    Alanazi, Fars K.; El-Badry, M.; Alsarra, Ibrahim A.

    2006-01-01

    Polymeric microparticles prepared by spray-drying techniques were investigated to enhance the dissolution rate of indomethacin (IM) in comparison with conventional microparticles prepared by co-precipitation solid dispersion method. Drug-polymer ratios and viscosity of polymeric solutions as potential factors were used in order to enhance the dissolution rate of IM. Spray-drying technique was used for preparing of microparticles using aqueous suspension of IM in hydroxypropyl methylcellulose (HPMC) polymer solution. The effect of drug-polymer ratios on dissolution rates of IM was studied in simulating intestinal medium. IM was analyzed spectrophotometrically at λ =320nm. For each drug-polymer ratios, low and high viscosity polymeric solutions were prepared and their impacts on the dissolution of IM were observed. Microparticles were morphologically characterized by optical microscopy. The interaction between IM and HPMC was studied by differential scanning caloremetry (DSC) and x-ray diffractometry (XRD). Spherical fluffy microparticles of IM were obtained using HPMC. It was observed that the prepared spray-dried microparticles significantly increase the dissolution rate of IM. The increase in dissolution rates was achieved with drug: polymer ratios 1: 1 as well as 1:2 and interestingly, the decrease in drug content in ratio exceeding 1:2 resulted in reduction in dissolution rates. Also, with all drug-polymer ratios, the low viscosity polymeric solutions gave the higher dissolution rates. In conclusion, HPMC microparticles loaded with IM were prepared by spray drying-technique and the potential of this technique to enhance the dissolution was studied. The findings indicate that the dissolution profile of IM microparticles prepared by spray -drying technique relied on drug-polymer ratios and viscosity of polymeric solutions. (author)

  4. Consistent model reduction of polymer chains in solution in dissipative particle dynamics: Model description

    KAUST Repository

    Moreno Chaparro, Nicolas

    2015-06-30

    We introduce a framework for model reduction of polymer chain models for dissipative particle dynamics (DPD) simulations, where the properties governing the phase equilibria such as the characteristic size of the chain, compressibility, density, and temperature are preserved. The proposed methodology reduces the number of degrees of freedom required in traditional DPD representations to model equilibrium properties of systems with complex molecules (e.g., linear polymers). Based on geometrical considerations we explicitly account for the correlation between beads in fine-grained DPD models and consistently represent the effect of these correlations in a reduced model, in a practical and simple fashion via power laws and the consistent scaling of the simulation parameters. In order to satisfy the geometrical constraints in the reduced model we introduce bond-angle potentials that account for the changes in the chain free energy after the model reduction. Following this coarse-graining process we represent high molecular weight DPD chains (i.e., ≥200≥200 beads per chain) with a significant reduction in the number of particles required (i.e., ≥20≥20 times the original system). We show that our methodology has potential applications modeling systems of high molecular weight molecules at large scales, such as diblock copolymer and DNA.

  5. Application of a novel 3-fluid nozzle spray drying process for the microencapsulation of therapeutic agents using incompatible drug-polymer solutions.

    Science.gov (United States)

    Sunderland, Tara; Kelly, John G; Ramtoola, Zebunnissa

    2015-04-01

    The aim of this study was to evaluate a novel 3-fluid concentric nozzle (3-N) spray drying process for the microencapsulation of omeprazole sodium (OME) using Eudragit L100 (EL100). Feed solutions containing OME and/or EL100 in ethanol were assessed visually for OME stability. Addition of OME solution to EL100 solution resulted in precipitation of OME followed by degradation of OME reflected by a colour change from colourless to purple and brown. This was related to the low pH of 2.8 of the EL100 solution at which OME is unstable. Precipitation and progressive discoloration of the 2-fluid nozzle (2-N) feed solution was observed over the spray drying time course. In contrast, 3-N solutions of EL100 or OME in ethanol were stable over the spray drying period. Microparticles prepared using either nozzle showed similar characteristics and outer morphology however the internal morphology was different. DSC showed a homogenous matrix of drug and polymer for 2-N microparticles while 3-N microparticles had defined drug and polymer regions distributed as core and coat. The results of this study demonstrate that the novel 3-N spray drying process can allow the microencapsulation of a drug using an incompatible polymer and maintain the drug and polymer in separate regions of the microparticles.

  6. Investigation of itraconazole ternary amorphous solid dispersions based on povidone and Carbopol.

    Science.gov (United States)

    Meng, Fan; Meckel, Jordan; Zhang, Feng

    2017-08-30

    We investigate a ternary system that consists of itraconazole (ITZ) and two polymers: povidone K12 and Carbopol 907. The interactions between these two polymers and their effects on the properties of ternary ITZ amorphous solid dispersions (ASDs) are studied. These two polymers can form a water-insoluble complex in acidic aqueous media. The critical pH is determined to be 4.17. The weight percentage of Carbopol 907 in the interpolymer complex range from 59 to 70%, depending on the initial ratios between these two polymers in the starting solutions. This complexation is driven by a negative enthalpy change from the H-bonding between the two polymers and a positive entropy change from the freed water molecules. Due to the slow precipitation of the interpolymer complex in aqueous media, the attempt to prepare ternary ASD using solvent-controlled coprecipitation is not successful. Melt extrusion is identified to be the only viable method to prepare this ternary ASD. We find that interpolymer complex-based ASDs are physically less stable and demonstrate the poorest drug-release properties when compared to individual polymer-based binary ASDs. This study illustrates that the too strong interaction between polymers in ternary ASDs is detrimental to their performance. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Two-dimensional charge transport in self-organized, high-mobility conjugated polymers

    DEFF Research Database (Denmark)

    Sirringhaus, H.; Brown, P.J.; Friend, R.H.

    1999-01-01

    Self-organization in many solution-processed, semiconducting conjugated polymers results in complex microstructures, in which ordered microcrystalline domains are embedded in an amorphous matrix(I). This has important consequences for electrical properties of these materials: charge transport...... of the ordered microcrystalline domains in the conjugated polymer poly(3-hexylthiophene), P3HT, Self-organization in P3HT results in a lamella structure with two-dimensional conjugated sheets formed by interchain stacking. We find that, depending on processing conditions, the lamellae can adopt two different...... of polymer transistors in logic circuits(5) and active-matrix displays(4,6)....

  8. A study of diazonium couplings with aromatic nucleophiles both in solution and on a polymer surface

    Science.gov (United States)

    Chng, Shuyun; Parker, Emily M.; Griffiths, Jon-Paul; Moloney, Mark G.; Wu, Linda Y. L.

    2017-04-01

    Diazonium coupling is a technique finding wider application to materials and biological science, for hybridization and linking processes, and for the construction of responsive surface functionality. For this reason, detailed examination of solution and surface processes was warranted, and results of such a study are reported here. The modification of polystyrene surfaces was examined as a model, and the process compared to a solution mimic using N,N-dimethylaniline. It was confirmed that solution and solid surface reactions proceed in a similar manner in terms of the chemical functionality generated, but with lower chemical efficiency and reaction times slower for the latter, in a reaction which was pH dependent. The solution process was shown to give only the trans-azo para- coupled products. Whilst there are clear similarities between the solution and surface chemistry, the efficiency of coupling at a surface is not necessarily replicated in the chemical yield of the mimicking solution processes, but nonetheless provides an alternative to other Click-type surface modifications. It should not be assumed that such couplings occur with quantitative efficiency at the surface.

  9. Removal of Chromium(VI from Aqueous Solutions Using Fe3O4 Magnetic Polymer Microspheres Functionalized with Amino Groups

    Directory of Open Access Journals (Sweden)

    Kai Wang

    2015-12-01

    Full Text Available Magnetic polymer microspheres (MPMs using glycidylmethacrylate (GMA as a functional monomer were synthesized in the presence of Fe3O4 nanoparticles via dispersion polymerization. After polymerization, the magnetic polymer microbeads were modified with ethylenediamine (EDA. The obtained ethylenediamine-functionalized magnetic microspheres (EDA-MPMs were characterized by scanning electron microscope (SEM, X-ray diffraction (XRD, vibrating-sample magnetometer (VSM and Fourier transform infrared (FT-IR spectroscopy. Then the EDA-MPMs were applied as adsorbents for the removal of Cr(VI from aqueous solution. Langmuir equation was appropriate to describe the experimental data. The maximum adsorption capacities obtained from the Langmuir model were 236.9, 242.1 and 253.2 mg/g at 298, 308 and 318 K, respectively. The Cr(VI adsorption equilibrium was established within 120 min and the adsorption kinetics was compatibly described by the pseudo-second order equation. The thermodynamic parameters (ΔG°, ΔH°, ΔS° of the sorption process revealed that the adsorption was spontaneous and was an endothermic process. The regeneration study demonstrated that the EDA-MPMs could be repeatedly utilized with no significant loss of adsorption efficiency.

  10. Modeling the dynamics of polymer chains in water solution. Application to sensor design

    Science.gov (United States)

    Starovoitov, V. N.; Starovoitova, B. N.

    2017-10-01

    This paper is devoted to a mathematical model of a chaotic dynamics of a polymer chain in water. The model consists of a parabolic equation that is derived according to the self-consistent field approach. This model is employed for the numerical simulation of a biological sensor that detects the presence of a specific protein in the fluid. The sensor is absolutely simple and seems to be new. Besides that, the suggested equation is interesting from the mathematical point of view. It includes a non-local operator of integration not only over the past time interval as in the problems with memory but also over the future time interval. It is unusual for parabolic problems.

  11. Bulk Heterojunction versus Diffused Bilayer: The Role of Device Geometry in Solution p-Doped Polymer-Based Solar Cells.

    Science.gov (United States)

    Loiudice, Anna; Rizzo, Aurora; Biasiucci, Mariano; Gigli, Giuseppe

    2012-07-19

    We exploit the effect of molecular p-type doping of P3HT in diffused bilayer (DB) polymer solar cells. In this alternative device geometry, the p-doping is accomplished in solution by blending the F4-TCNQ with P3HT. The p-doping both increases the film conductivity and reduces the potential barrier at the interface with the electrode. This results in an excellent power conversion efficiency of 4.02%, which is an improvement of ∼48% over the p-doped standard bulk heterojunction (BHJ) device. Combined VOC-light intensity dependence measurements and Kelvin probe force microscopy reveal that the DB device configuration is particularly advantageous, if compared to the conventional BHJ, because it enables optimization of the donor and acceptor layers independently to minimize the effect of trapping and to fully exploit the improved transport properties.

  12. Water-compatible 'aspartame'-imprinted polymer grafted on silica surface for selective recognition in aqueous solution.

    Science.gov (United States)

    Singh, Meenakshi; Kumar, Abhishek; Tarannum, Nazia

    2013-05-01

    Molecularly imprinted polymers selective for aspartame have been prepared using N-[2-ammonium-ethyl-piperazinium) maleimidopropane sulfonate copolymer bearing zwitterionic centres along the backbone via a surface-confined grafting procedure. Aspartame, a dipeptide, is commonly used as an artificial sweetener. Polymerisation on the surface was propagated by means of Michael addition reaction on amino-grafted silica surface. Electrostatic interactions along with complementary H-bonding and other hydrophobic interactions inducing additional synergetic effect between the template (aspartame) and the imprinted surface led to the formation of imprinted sites. The MIP was able to selectively and specifically take up aspartame from aqueous solution and certain pharmaceutical samples quantitatively. Hence, a facile, specific and selective technique using surface-grafted specific molecular contours developed for specific and selective uptake of aspartame in the presence of various interferrants, in different kinds of matrices is presented.

  13. Solution plasma applications for the synthesis/modification of inorganic nanostructured materials and the treatment of natural polymers

    Science.gov (United States)

    Watthanaphanit, Anyarat; Saito, Nagahiro

    2018-01-01

    Reducing the use of toxic chemicals, production steps, and time consumption are important concerns for researchers and process engineers to contribute in the quest for an efficient process in any production. If an equipment setup is simple, the process additionally becomes more profitable. Combination of the mentioned requirements has opened up various applications of the solution plasma process (SPP) — a physical means of generating plasma through an electrical discharge in a liquid medium at atmospheric pressure and room temperature. This review shows the progress of scientific research on the applications of the SPP for the synthesis/modification of inorganic nanostructured materials and the treatment of natural polymers. Development achieved in each application is demonstrated.

  14. High-performance solution-processed polymer ferroelectric field-effect transistors

    NARCIS (Netherlands)

    Naber, RCG; Tanase, C; Blom, PWM; Gelinck, GH; Marsman, AW; Touwslager, FJ; Setayesh, S; De Leeuw, DM; Naber, Ronald C.G.; Gelinck, Gerwin H.; Marsman, Albert W.; Touwslager, Fred J.

    We demonstrate a rewritable, non-volatile memory device with flexible plastic active layers deposited from solution. The memory device is a ferroelectric field-effect transistor (FeFET) made with a ferroelectric fluoropolymer and a bisalkoxy-substituted poly(p-phenylene vinylene) semiconductor

  15. Concentrated Polymer Solutions are Different from Melts: Role of Entanglement Molecular Weight

    DEFF Research Database (Denmark)

    Huang, Qian; Mednova, Olga; Rasmussen, Henrik K.

    2013-01-01

    We compare viscoelastic properties of several polystyrene solutions and melts with the same number of entanglements. It is demonstrated that the modulus and time can be shifted such that the linear viscoelastic properties are identical provided the number of entanglements are identical. However...

  16. Solvation consequences of polymer PVP with biological buffers MES, MOPS, and MOPSO in aqueous solutions

    International Nuclear Information System (INIS)

    Gupta, Bhupender S.; Chen, Bo-Ren; Lee, Ming-Jer

    2015-01-01

    Highlights: • Densities and viscosities data for aqueous solutions with PVP and/or buffer. • The studied buffers include MES, MOPS, and MOPSO. • DFT was used to estimate the binding energies of the (PVP + buffer) complexes. • The viscosity data were correlated with the Jones–Dole equation. • The investigated buffers behave as Kosmotropies. - Abstract: Densities and viscosities were measured for the aqueous buffer (MES, MOPS, or MOPSO) solutions containing different concentrations of polyvinylpyrrolidone (PVP) (5, 10, 15, 20 and 30) mass% at temperatures from (298.15 to 318.15) K under atmospheric pressure. The DFT calculations were also performed and the binding energies of the possible (PVP + buffer) complexes were obtained. The experimental and computational results reveal the interactions of the PVP with the constituent compounds in the aqueous buffer solutions. Additionally we have explored the solvation behavior of the buffers by measuring the densities and the viscosities data of the aqueous buffer solutions from (0.0 to 1.0) mol · kg"−"1 at temperatures from (298.15 to 318.15) K. The viscosity results were correlated with the Jones–Dole equation. The correlated results confirmed that all the investigated buffers behave as Kosmotropes (structure makers).

  17. Synthesis and characterization of a molecularly imprinted polymer for the isolation of the 16 US-EPA priority polycyclic aromatic hydrocarbons (PAHs) in solution.

    Science.gov (United States)

    Ncube, Somandla; Kunene, Phumlile; Tavengwa, Nikita T; Tutu, Hlanganani; Richards, Heidi; Cukrowska, Ewa; Chimuka, Luke

    2017-09-01

    A smart sorbent consisting of benzo[k]fluoranthene-imprinted and indeno[1 2 3-cd]pyrene-imprinted polymers mixed at 1:1 (w/w) was successfully screened from several cavity-tuning experiments and used in the isolation of polycyclic aromatic hydrocarbons from spiked solution. The polymer mixture showed high cross selectivity and affinity towards all the 16 US-EPA priority polycyclic aromatic hydrocarbons. The average extraction efficiency from a cyclohexane solution was 65 ± 13.3% (n = 16, SD). Batch adsorption and kinetic studies confirmed that the binding of polycyclic aromatic hydrocarbons onto the polymer particles resulted in formation of a monolayer and that the binding process was the rate limiting step. The imprinted polymer performance studies confirmed that the synthesized polymer had an imprinting efficiency of 103.9 ± 3.91% (n = 3, SD). A comparison of the theoretical number of cavities and the experimental binding capacity showed that the overall extent of occupation of the imprinted cavities in the presence of excess polycyclic aromatic hydrocarbons was 128 ± 6.45% (n = 3, SD). The loss of selectivity was estimated at 2.9% with every elution cycle indicating that the polymer can be re-used several times with limited loss of selectivity and sensitivity. The polymer combination has shown to be an effective adsorbent that can be used to isolate all the 16 US-EPA priority polycyclic aromatic hydrocarbons in solution. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Kinetics of the electropolymerization of aminoanthraquinone from aqueous solutions and analytical applications of the polymer film

    Directory of Open Access Journals (Sweden)

    Shymaa S. Medany

    2012-07-01

    Full Text Available Poly 1-amino-9, 10-anthraquinone (PAAQ films were prepared by the electropolymerization of 1-amino-9,10-anthraquinone (AAQ on platinum substrate from aqueous media, where 5.0 × 10−3 mol L−1 AAQ and 6.0 mol L−1 H2SO4 were used. The kinetics of the electropolymerization process was investigated by determining the change of the charge consumed during the polymerization process with time at different concentrations of both monomer and electrolyte. The results have shown that the process follows first order kinetics with respect to the monomer concentration. The order of the reaction with respect to the aqueous solvent i.e. H2SO4 was found to be negative. The polymer films were successfully used as sensors for the electroanalytical determination of many hazardous compounds, e.g. phenols, and biologically important materials like dopamine. The electroanalytical determination was based on the measurements of the oxidation current peak of the material in the cyclic voltammetric measurements. The cyclic voltammograms were recorded at a scan rate of 100 mV s−1 and different analyte concentrations. A calibration curve was constructed for each analyte, from which the determination of low concentrations of catechol and hydroquinone (HQ as examples of hazardous compounds present in waste water and also for ascorbic acid and dopamine as examples of valuable biological materials can be achieved.

  19. Fully Solution-Processed Inverted Polymer Solar Cells with Laminated Nanowire Electrodes

    KAUST Repository

    Gaynor, Whitney

    2010-01-26

    We demonstrate organic photovoltaic cells in which every layer is deposited by solution processing on opaque metal substrates, with efficiencies similar to those obtained in conventional device structures on transparent substrates. The device architecture is enabled by solution-processed, laminated silver nanowire films serving as the top transparent anode. The cells are based on the regioregular poly(3- hexylthiophene) and C 61 butyric acid methyl ester bulk heterojunction and reach an efficiency of 2.5% under 100 mW/cm 2 of AM 1.5G illumination. The metal substrates are adequate barriers to moisture and oxygen, in contrast to transparent plastics that have previously been used, giving rise to the possibility of roll-to-roll solutionprocessed solar cells that are packaged by lamination to glass substrates, combining the cost advantage of roll-toroll processing with the barrier properties of glass and metal foil. © 2010 American Chemical Society.

  20. Fully Solution-Processed Inverted Polymer Solar Cells with Laminated Nanowire Electrodes

    KAUST Repository

    Gaynor, Whitney; Lee, Jung-Yong; Peumans, Peter

    2010-01-01

    We demonstrate organic photovoltaic cells in which every layer is deposited by solution processing on opaque metal substrates, with efficiencies similar to those obtained in conventional device structures on transparent substrates. The device architecture is enabled by solution-processed, laminated silver nanowire films serving as the top transparent anode. The cells are based on the regioregular poly(3- hexylthiophene) and C 61 butyric acid methyl ester bulk heterojunction and reach an efficiency of 2.5% under 100 mW/cm 2 of AM 1.5G illumination. The metal substrates are adequate barriers to moisture and oxygen, in contrast to transparent plastics that have previously been used, giving rise to the possibility of roll-to-roll solutionprocessed solar cells that are packaged by lamination to glass substrates, combining the cost advantage of roll-toroll processing with the barrier properties of glass and metal foil. © 2010 American Chemical Society.

  1. Polymer solar cells with efficiency >10% enabled via a facile solution-processed Al-doped ZnO electron transporting layer

    KAUST Repository

    Jagadamma, Lethy Krishnan; Al-Senani, Mohammed; Amassian, Aram

    2015-01-01

    The present work details a facile and low-temperature (125C) solution-processed Al-doped ZnO (AZO) buffer layer functioning very effectively as electron accepting/hole blocking layer for a wide range of polymer:fullerene bulk heterojunction systems

  2. Phase separation in polymer solutions. II. Determination of thermodynamic parameters of poly (2,6-dimethyl-1,4-phenylene oxide) toluene mixtures

    NARCIS (Netherlands)

    van Emmerik, P.T.; Smolders, C.A.

    1972-01-01

    In liquid systems where it is possible to perform light scattering experiments at the melting points of polymer solutions without nucleation taking place because of undercooling, the thermodynamic parameters necessary to calculate the correction parameter g in the Flory-Huggins equation as modified

  3. Inorganic polymers from laterite using activation with phosphoric acid and alkaline sodium silicate solution: Mechanical and microstructural properties

    International Nuclear Information System (INIS)

    Enzo Ferrari, Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy))" data-affiliation=" (Dipartimento di Ingegneria Enzo Ferrari, Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy))" >Lassinantti Gualtieri, Magdalena; Enzo Ferrari, Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy))" data-affiliation=" (Dipartimento di Ingegneria Enzo Ferrari, Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy))" >Romagnoli, Marcello; Pollastri, Simone; Gualtieri, Alessandro F.

    2015-01-01

    Geopolymers from laterite, an iron-rich soil available in developing countries, have great potential as building materials. In this work, laterite from Togo (Africa) was used to prepare geopolymers using both phosphoric acid and alkaline sodium silicate solution. Microstructural properties were investigated by scanning electron microscopy, X-ray powder diffraction and mercury porosimetry, whereas thermal properties were evaluated by thermal analyses. The local environment of iron was studied by X-ray Absorption Spectroscopy (XANES region). The mechanical properties were determined. Modulus of Rupture and Young's modulus fell in the ranges 3.3–4.5 MPa and 12–33 GPa, respectively, rendering the materials good candidates for construction purposes. Heating above 900 °C results in weight-gain, presumably due to iron redox reactions. X-ray Absorption Spectroscopy data evidence changes in the chemical and structural environments of iron following thermal treatment of geopolymers. These changes indicate interaction between the geopolymer structure and iron during heating, possibly leading to redox properties. -- Highlights: •Geopolymerization of laterite is promising for fabrication of building materials. •Both phosphoric acid and alkaline sodium silicate solution can be used for activation. •Thermally activated redox properties of the inorganic polymers were observed

  4. Inorganic polymers from laterite using activation with phosphoric acid and alkaline sodium silicate solution: Mechanical and microstructural properties

    Energy Technology Data Exchange (ETDEWEB)

    Lassinantti Gualtieri, Magdalena, E-mail: magdalena.gualtieri@unimore.it [Dipartimento di Ingegneria " Enzo Ferrari" , Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy); Romagnoli, Marcello [Dipartimento di Ingegneria " Enzo Ferrari" , Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy); Pollastri, Simone; Gualtieri, Alessandro F. [Dipartimento di Scienze Chimiche e Geologiche, Università degli studi di Modena e Reggio Emilia, Via S. Eufemia 19I, I-41121 Modena (Italy)

    2015-01-15

    Geopolymers from laterite, an iron-rich soil available in developing countries, have great potential as building materials. In this work, laterite from Togo (Africa) was used to prepare geopolymers using both phosphoric acid and alkaline sodium silicate solution. Microstructural properties were investigated by scanning electron microscopy, X-ray powder diffraction and mercury porosimetry, whereas thermal properties were evaluated by thermal analyses. The local environment of iron was studied by X-ray Absorption Spectroscopy (XANES region). The mechanical properties were determined. Modulus of Rupture and Young's modulus fell in the ranges 3.3–4.5 MPa and 12–33 GPa, respectively, rendering the materials good candidates for construction purposes. Heating above 900 °C results in weight-gain, presumably due to iron redox reactions. X-ray Absorption Spectroscopy data evidence changes in the chemical and structural environments of iron following thermal treatment of geopolymers. These changes indicate interaction between the geopolymer structure and iron during heating, possibly leading to redox properties. -- Highlights: •Geopolymerization of laterite is promising for fabrication of building materials. •Both phosphoric acid and alkaline sodium silicate solution can be used for activation. •Thermally activated redox properties of the inorganic polymers were observed.

  5. Multilayered phosphorescent polymer light-emitting diodes using a solution-processed n-doped electron transport layer

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yuehua; Zhang, Mengke [Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing University of Posts & Telecommunications, Nanjing 210023 (China); Zhang, Xinwen, E-mail: iamxwzhang@njupt.edu.cn [Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing University of Posts & Telecommunications, Nanjing 210023 (China); Lei, Zhenfeng; Zhang, Xiaolin; Hao, Lin; Fan, Quli [Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing University of Posts & Telecommunications, Nanjing 210023 (China); Lai, Wenyong, E-mail: iamwylai@njupt.edu.cn [Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing University of Posts & Telecommunications, Nanjing 210023 (China); Huang, Wei [Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing University of Posts & Telecommunications, Nanjing 210023 (China); Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing 211816 (China)

    2017-06-15

    Efficient multilayered green phosphorescent polymer light-emitting devices (PhPLEDs) were successfully fabricated using a solution-processed n-doped small molecular electron transporting layer (ETL) composed of 1,3,5-tris(N-phenyl-benzimidazol-2-yl)-benzene (TPBi) and CsF. We found that the electroluminescence properties of the devices with n-doped ETLs are significantly improved. The maximum luminance efficiency of the device with 7.5 wt% CsF doped TPBi ETL reached 26.9 cd/A, which is 1.5 times as large as that of the undoped device. The impedance spectra of the devices and electron transport properties of the CsF doped ETLs demonstrate that doping dramatically decreases the impedance and enhances the electrical conductivity. Similarly, enhanced performance of PhPLED is also observed by use of CsF-doped 4,7-diphenyl-1,10 -phenanthroline (BPhen) ETL. These results demonstrate that CsF can be used as an effective n-dopant in solution-processed devices.

  6. Multilayered phosphorescent polymer light-emitting diodes using a solution-processed n-doped electron transport layer

    International Nuclear Information System (INIS)

    Chen, Yuehua; Zhang, Mengke; Zhang, Xinwen; Lei, Zhenfeng; Zhang, Xiaolin; Hao, Lin; Fan, Quli; Lai, Wenyong; Huang, Wei

    2017-01-01

    Efficient multilayered green phosphorescent polymer light-emitting devices (PhPLEDs) were successfully fabricated using a solution-processed n-doped small molecular electron transporting layer (ETL) composed of 1,3,5-tris(N-phenyl-benzimidazol-2-yl)-benzene (TPBi) and CsF. We found that the electroluminescence properties of the devices with n-doped ETLs are significantly improved. The maximum luminance efficiency of the device with 7.5 wt% CsF doped TPBi ETL reached 26.9 cd/A, which is 1.5 times as large as that of the undoped device. The impedance spectra of the devices and electron transport properties of the CsF doped ETLs demonstrate that doping dramatically decreases the impedance and enhances the electrical conductivity. Similarly, enhanced performance of PhPLED is also observed by use of CsF-doped 4,7-diphenyl-1,10 -phenanthroline (BPhen) ETL. These results demonstrate that CsF can be used as an effective n-dopant in solution-processed devices.

  7. Removal of Sr from radioactive waste solutions by polymer enhanced ultra filtration: study of selectivity and mechanism of the process

    International Nuclear Information System (INIS)

    Kedari, C.S.; Yadav, J.S.; Gandhi, P.M.; Banerjee, K.

    2016-01-01

    The removal of 90 Sr in liquid radioactive wastes is an important issue for waste disposal. Because of the physical and biological half-life of 90 Sr, it is one of the most hazardous radionuclides for internal exposure. Accumulation in bones tissues and high-energy beta particles from its daughter nuclide, 90 Y (half-life: 64.1 h), cause the damage to bone marrow. These characteristics are forcing the implementation of monitoring 90 Sr activities and its elimination from the industrial waste solutions. Filtration through semi permeable membrane with the potential of selective retention is a well-established commercial technique, which also has great applicability in nuclear waste processing. The UF based separation is a solute fractionation using appropriate pore size membrane as a sieve. The advantage of working with UF is: high throughput can be achieved as compared to RO while using low driving pressure and temperature. The objective of this research was to determine the effectiveness of separation of divalent strontium by complexing with water soluble cation exchange polymer and its removal by ultra filtration

  8. Short range order in amorphous polycondensates

    Energy Technology Data Exchange (ETDEWEB)

    Lamers, C.; Richter, D.; Schweika, W. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Festkoerperforschung; Batoulis, J.; Sommer, K. [Bayer AG, Leverkusen (Germany); Cable, J.W. [Oak Ridge National Lab., TN (United States); Shapiro, S.M. [Brookhaven National Lab., Upton, NY (United States)

    1992-12-01

    The static coherent structure factors S(Q) of the polymer glass Bisphenol-A-Polycarbonate and its chemical variation Bisphenol-A- Polyctherkctone- both in differently deuterated versions- have been measured by spin polarized neutron scattering. The method of spin polarization analysis provided an experimental separation of coherent and incoherent scattering and a reliable intensity calibration. Results are compared to structure factors calculated for model structures which were obtained by ``amorphous cell`` computer simulations. In general reasonable agreement is found between experiment and simulation; however, certain discrepancies hint at an insufficient structural relaxation in the amorphous cell method. 15 refs, 1 fig, 1 tab.

  9. All solution processed tandem polymer solar cells based on thermocleavable materials

    DEFF Research Database (Denmark)

    Hagemann, Ole; Bjerring, Morten; Nielsen, Niels Chr.

    2008-01-01

    efficiently solved. Devices comprised a transparent front cathode based on solution processed zinc oxide nanoparticles, a large band gap active layer based on a bulk heterojunction between zinc oxide and poly(3-carboxydithiophene) (P3CT) followed by a layer of PEDOT:PSS processed from water. The second cell...... in the stack employed a zinc oxide front cathode processed on top of the PEDOT:PSS layer from an organic solvent, a low band gap active layer based on a bulk heterojunction between zinc oxide and the novel poly(carboxyterthiophene-co-diphenylthienopyrazine) (P3CTTP) followed by a layer of PEDOT:PSS again...

  10. Theory of amorphous ices.

    Science.gov (United States)

    Limmer, David T; Chandler, David

    2014-07-01

    We derive a phase diagram for amorphous solids and liquid supercooled water and explain why the amorphous solids of water exist in several different forms. Application of large-deviation theory allows us to prepare such phases in computer simulations. Along with nonequilibrium transitions between the ergodic liquid and two distinct amorphous solids, we establish coexistence between these two amorphous solids. The phase diagram we predict includes a nonequilibrium triple point where two amorphous phases and the liquid coexist. Whereas the amorphous solids are long-lived and slowly aging glasses, their melting can lead quickly to the formation of crystalline ice. Further, melting of the higher density amorphous solid at low pressures takes place in steps, transitioning to the lower-density glass before accessing a nonequilibrium liquid from which ice coarsens.

  11. Polymer Concentration-Controlled Substrate Specificity in Solvolysis of p-Nitrophenyl Alkanoates Catalyzed by 4-(Dialkylamino)pyridine- Functionalized Polymer in Aqueous Methanol Solution

    National Research Council Canada - National Science Library

    Wang, Guang-Jia

    1996-01-01

    The substrate specificity in solvolysis reactions of p-nitrophenyl alkanoates 2 (n=2-18) catalyzed by 4-(dialkylamino)pyridine-functionalized polymer 1 can be controlled by the concentration of 1 in 1...

  12. Selective removal/recovery of RCRA metals from waste and process solutions using polymer filtration{trademark} technology

    Energy Technology Data Exchange (ETDEWEB)

    Smith, B.F. [Los Alamos National Lab., NM (United States)

    1997-10-01

    Resource Conservation and Recovery Act (RCRA) metals are found in a number of process and waste streams at many DOE, U.S. Department of Defense, and industrial facilities. RCRA metals consist principally of chromium, mercury, cadmium, lead, and silver. Arsenic and selenium, which form oxyanions, are also considered RCRA elements. Discharge limits for each of these metals are based on toxicity and dictated by state and federal regulations (e.g., drinking water, RCRA, etc.). RCRA metals are used in many current operations, are generated in decontamination and decommissioning (D&D) operations, and are also present in old process wastes that require treatment and stabilization. These metals can exist in solutions, as part of sludges, or as contaminants on soils or solid surfaces, as individual metals or as mixtures with other metals, mixtures with radioactive metals such as actinides (defined as mixed waste), or as mixtures with a variety of inert metals such as calcium and sodium. The authors have successfully completed a preliminary proof-of-principle evaluation of Polymer Filtration{trademark} (PF) technology for the dissolution of metallic mercury and have also shown that they can remove and concentrate RCRA metals from dilute solutions for a variety of aqueous solution types using PF technology. Another application successfully demonstrated is the dilute metal removal of americium and plutonium from process streams. This application was used to remove the total alpha contamination to below 30 pCi/L for the wastewater treatment plant at TA-50 at Los Alamos National Laboratory (LANL) and from nitric acid distillate in the acid recovery process at TA-55, the Plutonium Facility at LANL (ESP-CP TTP AL16C322). This project will develop and optimize the PF technology for specific DOE process streams containing RCRA metals and coordinate it with the needs of the commercial sector to ensure that technology transfer occurs.

  13. Selective removal/recovery of RCRA metals from waste and process solutions using polymer filtration trademark technology

    International Nuclear Information System (INIS)

    Smith, B.F.

    1997-01-01

    Resource Conservation and Recovery Act (RCRA) metals are found in a number of process and waste streams at many DOE, U.S. Department of Defense, and industrial facilities. RCRA metals consist principally of chromium, mercury, cadmium, lead, and silver. Arsenic and selenium, which form oxyanions, are also considered RCRA elements. Discharge limits for each of these metals are based on toxicity and dictated by state and federal regulations (e.g., drinking water, RCRA, etc.). RCRA metals are used in many current operations, are generated in decontamination and decommissioning (D ampersand D) operations, and are also present in old process wastes that require treatment and stabilization. These metals can exist in solutions, as part of sludges, or as contaminants on soils or solid surfaces, as individual metals or as mixtures with other metals, mixtures with radioactive metals such as actinides (defined as mixed waste), or as mixtures with a variety of inert metals such as calcium and sodium. The authors have successfully completed a preliminary proof-of-principle evaluation of Polymer Filtration trademark (PF) technology for the dissolution of metallic mercury and have also shown that they can remove and concentrate RCRA metals from dilute solutions for a variety of aqueous solution types using PF technology. Another application successfully demonstrated is the dilute metal removal of americium and plutonium from process streams. This application was used to remove the total alpha contamination to below 30 pCi/L for the wastewater treatment plant at TA-50 at Los Alamos National Laboratory (LANL) and from nitric acid distillate in the acid recovery process at TA-55, the Plutonium Facility at LANL (ESP-CP TTP AL16C322). This project will develop and optimize the PF technology for specific DOE process streams containing RCRA metals and coordinate it with the needs of the commercial sector to ensure that technology transfer occurs

  14. Microfluidic rheometry of a polymer solution by micron resolution particle image velocimetry: a model validation study

    International Nuclear Information System (INIS)

    Hemaka Bandalusena, H C; Zimmerman, William B; Rees, Julia M

    2009-01-01

    The main purpose of this study is to model non-Newtonian fluid flows in microgeometries. Velocity fields of dilute xanthan gum solutions in a microfluidic T-junction have been measured for pressure-driven flow using micron resolution particle image velocimetry (µ-PIV). Xanthan gum at a fixed concentration is a power-law fluid. Varying the concentration changes the rheology, effectively altering the power-law parameters reflecting the changes in the fluid's shear response since viscoelasticity and extensional viscosity are negligible for dilute solutions of this substance. As the flow is forced to turn the corner of the T-junction, a range of shear rates, and hence viscosities, is produced. If this feature could be incorporated into a viscometer, then potentially the constitutive parameters of a complex fluid could be ascertained from a single experiment. A mathematical model based on a finite element technique has been developed to simulate the fluid flow in the experimental system. Model predictions of the velocity field are found to agree well (less than 5% error) with observations, thus validating the model

  15. Morphologies and separation characteristics of polyphenyl sulfone-based solvent resistant nanofiltration membranes: Effect of polymer concentration in casting solution and membrane pretreatment condition

    International Nuclear Information System (INIS)

    Sani, Nur Aimie Abdullah; Lau, Woei Jye; Ismail, Ahmad Fauzi

    2015-01-01

    The performance of polyphenylsulfone (PPSU) solvent resistant nanofiltration (SRNF)-based flat sheet membranes prepared from phase inversion method was investigated by varying the concentration of polymer in the dope solution and condition of membrane pretreatment process. The membrane properties were characterized by SEM, FTIR, AFM and contact angle goniometer, while their performance was evaluated by measuring methanol flux and rejection of different molecular weight of dyes (ranging from 269 to 1,470 g/mol) in methanol. The experimental results showed that the polymer concentration has great impact not only on the final membrane morphology but also its separation characteristics. Increasing polymer concentration from 17 to 25wt% tended to suppress finger-like structure and more pear-like pores were developed, causing methanol flux to decrease. This can be explained by the decrease in molecular weight cut off (MWCO) of the membrane prepared at high polymer concentration. With respect to the effect of membrane pretreatment conditions, the rejection of membrane was negatively affected with longer immersion period in methanol solution prior to filtration experiment. The variation in membrane rejection can be attributed to the rearrangement of the polymer chain, which results in membrane swelling and/or change of membrane surface hydrophilicity

  16. Morphologies and separation characteristics of polyphenyl sulfone-based solvent resistant nanofiltration membranes: Effect of polymer concentration in casting solution and membrane pretreatment condition

    Energy Technology Data Exchange (ETDEWEB)

    Sani, Nur Aimie Abdullah; Lau, Woei Jye; Ismail, Ahmad Fauzi [Universiti Teknologi Malaysia, Skudai (Malaysia)

    2015-04-15

    The performance of polyphenylsulfone (PPSU) solvent resistant nanofiltration (SRNF)-based flat sheet membranes prepared from phase inversion method was investigated by varying the concentration of polymer in the dope solution and condition of membrane pretreatment process. The membrane properties were characterized by SEM, FTIR, AFM and contact angle goniometer, while their performance was evaluated by measuring methanol flux and rejection of different molecular weight of dyes (ranging from 269 to 1,470 g/mol) in methanol. The experimental results showed that the polymer concentration has great impact not only on the final membrane morphology but also its separation characteristics. Increasing polymer concentration from 17 to 25wt% tended to suppress finger-like structure and more pear-like pores were developed, causing methanol flux to decrease. This can be explained by the decrease in molecular weight cut off (MWCO) of the membrane prepared at high polymer concentration. With respect to the effect of membrane pretreatment conditions, the rejection of membrane was negatively affected with longer immersion period in methanol solution prior to filtration experiment. The variation in membrane rejection can be attributed to the rearrangement of the polymer chain, which results in membrane swelling and/or change of membrane surface hydrophilicity.

  17. Comparison of the influence of polyaspartic acid and polylysine functional groups on the adsorption at the Cr2O3-Aqueous polymer solution interface

    Science.gov (United States)

    Ostolska, Iwona; Wiśniewska, Małgorzata

    2014-08-01

    Polyamino acids are a group of synthesized polymers obtained by polymerization of a given kind of amino acid monomer. Because of high biodegradability of this class of polymers, they can be used as flocculation or stabilization agents in the environmental aspects. Therefore determination of their influence on the stability of the aqueous suspension of metal oxides is important. An influence of different functional groups of polyamino acids, their molecular weight and concentration on the adsorption at the chromium (III) oxide (Cr2O3)-aqueous solution interface was determined. Experiments were carried out for four values of solution pH varying from 3 to 10 (3, 4, 7.6 and 10, respectively). Two polymers were used: anionic polyaspartic acid (ASP) of 6800 and 27,000 as well as polylysine (LYS) of 4900 and 33,000 molecular weights. Changes of surface charge density of colloidal Cr2O3 in the presence and in the absence of macromolecular substances were determined using potentiometric titration. In these studies the influence of the concentration and molecular weight of the ionic polymers on the pHpzc value was determined. Additionally, due to the lack of appropriate literature data, potentiometric titration of the selected polymers was performed to determine pKa values.

  18. Solubility of crystalline organic compounds in high and low molecular weight amorphous matrices above and below the glass transition by zero enthalpy extrapolation.

    Science.gov (United States)

    Amharar, Youness; Curtin, Vincent; Gallagher, Kieran H; Healy, Anne Marie

    2014-09-10

    Pharmaceutical applications which require knowledge of the solubility of a crystalline compound in an amorphous matrix are abundant in the literature. Several methods that allow the determination of such data have been reported, but so far have only been applicable to amorphous polymers above the glass transition of the resulting composites. The current work presents, for the first time, a reliable method for the determination of the solubility of crystalline pharmaceutical compounds in high and low molecular weight amorphous matrices at the glass transition and at room temperature (i.e. below the glass transition temperature), respectively. The solubilities of mannitol and indomethacin in polyvinyl pyrrolidone (PVP) K15 and PVP K25, respectively were measured at different temperatures. Mixtures of undissolved crystalline solute and saturated amorphous phase were obtained by annealing at a given temperature. The solubility at this temperature was then obtained by measuring the melting enthalpy of the crystalline phase, plotting it as a function of composition and extrapolating to zero enthalpy. This new method yielded results in accordance with the predictions reported in the literature. The method was also adapted for the measurement of the solubility of crystalline low molecular weight excipients in amorphous active pharmaceutical ingredients (APIs). The solubility of mannitol, glutaric acid and adipic acid in both indomethacin and sulfadimidine was experimentally determined and successfully compared with the difference between their respective calculated Hildebrand solubility parameters. As expected from the calculations, the dicarboxylic acids exhibited a high solubility in both amorphous indomethacin and sulfadimidine, whereas mannitol was almost insoluble in the same amorphous phases at room temperature. This work constitutes the first report of the methodology for determining an experimentally measured solubility for a low molecular weight crystalline solute

  19. Lagrangian theory with zero component. Application to the study of the polymers in solution (chains with exclued volume) and of the properties of electrons in a random potential

    International Nuclear Information System (INIS)

    Des Cloizeaux, J.

    1976-01-01

    The Lagrangian theory of a field with n components can be generalized for values of n which are not integers and in particular for n=0. This extension is made by introducing ordered Green's functions. It is shown how the zero components Lagrangian theory can be used to describe the behaviour of an isolated polymer or of a solution of polymers with large molecular masses. It is remarked that by analytic continuation with respect to the coupling constant, it should be possible to study the properties of electrons in a random potential and perhaps the nature of the mobility edges [fr

  20. Formation of biodegradated polymers as components of future composite materials on the basis of shape memory alloy of medical appointment

    Science.gov (United States)

    Nasakina, E. O.; Baikin, A. S.; Sergiyenko, K. V.; Kaplan, M. A.; Konushkin, S. V.; Yakubov, A. D.; Izvin, A. V.; Sudarchikova, M. A.; Sevost’yanov, M. A.; Kolmakov, A. G.

    2018-04-01

    The processes of formation of polymer polylactide or polyglycylidactide films for the subsequent creation of a layered composite with a biodegradable layer on the basis of a nickel-free shape memory alloy TiNbTaZr are studied. The structure of the samples was determined using an SEM. The correspondence of morphology of surfaces of and the substrate itself is noted. High adhesion of the polymer to the future basis of the developed composite material is supposed. The formed films is homogeneous and amorphous throughout the polymer volume. By varying the volume of solutions, it is possible to obtain films of a given thickness for any type of polymer, its molecular weight, and the solution concentration of the polymer in chloroform. Poly (glycolide-lactide) should be more plastic than polylactide.

  1. Comparative study of hydro soluble polymers solutions and surfactants aiming the polymer-rock interactions in consolidated sandstone; Estudo comparativo de solucoes de polimeros hidrossoluveis e tensoativos visando as interacoes polimero-rocha em arenito consolidado

    Energy Technology Data Exchange (ETDEWEB)

    Valentim, Adriano Cesar M.; Marcelino, Cleuton Pereira; Medeiros, Ana Catarina R.; Garcia, Rosangela Balaban [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Lab. de Pesquisa em Petroleo (LAPET)

    2004-07-01

    The polyacrylamide is one of the main polymers used in the petroleum industry. Among its properties, stands out the capacity to alter the permeability of the rock to water. However, the polyacrylamide presents some limitations, such as low tolerance to the presence of salts, what can promote its precipitation resulting in low oil recovery efficiency. The application of the polymer in emulsion can promote a larger stability, due to the presence of a surfactant, which has the capacity to modify the interfacial tension and to form a film between the phases of the emulsion. Thereby, the injection of a polymer emulsion can promote an increase of oil recovery. In this work, a preliminary study of the effect of a anionic surfactant (SDS) and polyacrylamides (anionic and neutral) on the surface tension and rheology is presented in aqueous solutions contend salt (NaCl). The results showed surface tension of the mixtures had been remained constant and low (around 32 mN/m), independent of the polymer concentration. A viscosity reduction was observed at polymeric solutions as much in presence of salt, as in presence of the surfactant. Both the samples showed a pseudo plastic behavior. (author)

  2. Adsorption of Cr (III from aqueous solution by two forms of a superabsorbant polymer : parametric study and effect of activation mode

    Directory of Open Access Journals (Sweden)

    Ouass A.

    2018-01-01

    Full Text Available The adsorption of chromium ions Cr3+ using two forms of a superabsorbant polymer PANa from aqueous solution was investigated. On one hand the equilibrium pH with the distilled water and the pH of point of zero charge have been studied in order to characterize the acid-base behavior of both of PANa forms. On the other hand, the effect of contact time between PANa and the metallic solution and stirring speed of aqueous solution on the adsorption rate were established to highlight the importance of PANa as an efficient adsorbent of chromium ions Cr3+.

  3. Structural and Electrical Properties of Graphene Oxide-Doped PVA/PVP Blend Nanocomposite Polymer Films

    Directory of Open Access Journals (Sweden)

    S. K. Shahenoor Basha

    2018-01-01

    Full Text Available Graphene oxide (GO nanoparticles were incorporated in PVA/PVP blend polymers for the preparation of nanocomposite polymer films by the solution cast technique. XRD, FTIR, DSC, SEM, and UV-visible studies were performed on the prepared nanocomposite polymer films. XRD revealed the amorphous nature of the prepared films. Thermal analysis of the nanocomposite polymer films was analyzed by DSC. SEM revealed the morphological features and the degree of roughness of the samples. DC conductivity studies were under taken on the samples, and the conductivity was found to be 6.13 × 10−4 S·cm−1 for the polymer film prepared at room temperature. A solid-state battery has been fabricated with the chemical composition of Mg+/(PVA/PVP  :  GO/(I2 + C + electrolyte, and its cell parameters like power density and current density were calculated.

  4. Fluorescence and picosecond induced absorption from the lowest singlet excited states of quercetin in solutions and polymer films

    Science.gov (United States)

    Bondarev, S. L.; Tikhomirov, S. A.; Buganov, O. V.; Knyukshto, V. N.; Raichenok, T. F.

    2017-03-01

    The spectroscopic and photophysical properties of the biologically important plant antioxidant quercetin in organic solvents, polymer films of polyvinyl alcohol, and a buffer solution at pH 7.0 are studied by stationary luminescence and femtosecond laser spectroscopy at room temperature and 77 K. The large magnitude of the dipole moment of the quercetin molecule in the excited Franck-Condon state μ e FC = 52.8 C m indicates the dipolar nature of quercetin in this excited state. The transient induced absorption spectra S 1→ S n in all solvents are characterized by a short-wave band at λ abs max = 460 nm with exponential decay times in the range of 10.0-20.0 ps. In the entire spectral range at times of >100 ps, no residual induced absorption was observed that could be attributed to the triplet-triplet transitions T 1 → T k in quercetin. In polar solvents, two-band fluorescence was also recorded at room temperature, which is due to the luminescence of the initial enol form of quercetin ( 415 nm) and its keto form with a transferred proton (550 nm). The short-wave band is absent in nonpolar 2-methyltetrahydrofuran (2-MTHF). The spectra of fluorescence and fluorescence excitation exhibit a low dependence on the wavelength of excitation and detection, which may be related to the solvation and conformational changes in the quercetin molecule. Decreasing the temperature of a glassy-like freezing quercetin solution in ethanol and 2-MTHF to 77 K leads to a strong increase in the intensity (by a factor of 100) of both bands. The energy circuits for the proton transfer process are proposed depending on the polarity of the medium. The main channel for the exchange of electronic excitation energy in the quercetin molecule at room temperature is the internal conversion S 1 ⇝ S 0, induced by the state with a proton transfer.

  5. Solution-Processed n-Type Graphene Doping for Cathode in Inverted Polymer Light-Emitting Diodes.

    Science.gov (United States)

    Kwon, Sung-Joo; Han, Tae-Hee; Kim, Young-Hoon; Ahmed, Towfiq; Seo, Hong-Kyu; Kim, Hobeom; Kim, Dong Jin; Xu, Wentao; Hong, Byung Hee; Zhu, Jian-Xin; Lee, Tae-Woo

    2018-02-07

    n-Type doping with (4-(1,3-dimethyl-2,3-dihydro-1H-benzoimidazol-2-yl)phenyl) dimethylamine (N-DMBI) reduces a work function (WF) of graphene by ∼0.45 eV without significant reduction of optical transmittance. Solution process of N-DMBI on graphene provides effective n-type doping effect and air-stability at the same time. Although neutral N-DMBI act as an electron receptor leaving the graphene p-doped, radical N-DMBI acts as an electron donator leaving the graphene n-doped, which is demonstrated by density functional theory. We also verify the suitability of N-DMBI-doped n-type graphene for use as a cathode in inverted polymer light-emitting diodes (PLEDs) by using various analytical methods. Inverted PLEDs using a graphene cathode doped with N-DMBI radical showed dramatically improved device efficiency (∼13.8 cd/A) than did inverted PLEDs with pristine graphene (∼2.74 cd/A). N-DMBI-doped graphene can provide a practical way to produce graphene cathodes with low WF in various organic optoelectronics.

  6. Solution processed transition metal oxide anode buffer layers for efficiency and stability enhancement of polymer solar cells

    Science.gov (United States)

    Ameen, M. Yoosuf; Shamjid, P.; Abhijith, T.; Reddy, V. S.

    2018-01-01

    Polymer solar cells were fabricated with solution-processed transition metal oxides, MoO3 and V2O5 as anode buffer layers (ABLs). The optimized device with V2O5 ABL exhibited considerably higher power conversion efficiency (PCE) compared to the devices based on MoO3 and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) ABLs. The space charge limited current measurements and impedance spectroscopy results of hole-only devices revealed that V2O5 provided a very low charge transfer resistance and high hole mobility, facilitating efficient hole transfer from the active layer to the ITO anode. More importantly, incorporation of V2O5 as ABL resulted in substantial improvement in device stability compared to MoO3 and PEDOT:PSS based devices. Unencapsulated PEDOT:PSS-based devices stored at a relative humidity of 45% have shown complete failure within 96 h. Whereas, MoO3 and V2O5 based devices stored in similar conditions retained 22% and 80% of their initial PCEs after 96 h. Significantly higher stability of the V2O5-based device is ascribed to the reduction in degradation of the anode/active layer interface, as evident from the electrical measurements.

  7. Self-consistent field theoretic simulations of amphiphilic triblock copolymer solutions: Polymer concentration and chain length effects

    Directory of Open Access Journals (Sweden)

    X.-G. Han

    2014-06-01

    Full Text Available Using the self-consistent field lattice model, polymer concentration φP and chain length N (keeping the length ratio of hydrophobic to hydrophilic blocks constant the effects on temperature-dependent behavior of micelles are studied, in amphiphilic symmetric ABA triblock copolymer solutions. When chain length is increased, at fixed φP, micelles occur at higher temperature. The variations of average volume fraction of stickers φcos and the lattice site numbers Ncols at the micellar cores with temperature are dependent on N and φP, which demonstrates that the aggregation of micelles depends on N and φP. Moreover, when φP is increased, firstly a peak appears on the curve of specific heat CV for unimer-micelle transition, and then in addition a primary peak, the secondary peak, which results from the remicellization, is observed on the curve of CV. For a long chain, in intermediate and high concentration regimes, the shape of specific heat peak markedly changes, and the peak tends to be a more broad peak. Finally, the aggregation behavior of micelles is explained by the aggregation way of amphiphilic triblock copolymer. The obtained results are helpful in understanding the micellar aggregation process.

  8. Influence of electric field on the properties of the polymer stabilized luminescent quantum dots in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Zharkova, Irina S.; Markina, Natalia E. [Saratov State University, Astrakhanskaya 83, 410012 Saratov (Russian Federation); Markin, Alexey V., E-mail: av_markin@mail.ru [Saratov State University, Astrakhanskaya 83, 410012 Saratov (Russian Federation); Drozd, Daniil D.; Speranskaya, Elena S. [Saratov State University, Astrakhanskaya 83, 410012 Saratov (Russian Federation); Goryacheva, Irina Yu. [Saratov State University, Astrakhanskaya 83, 410012 Saratov (Russian Federation); Saint-Petersburg State University, Universitetskii pr. 26, 198504 Petrodvorets, Saint-Petersburg (Russian Federation)

    2016-08-15

    The application of external electric field for verification of quantum dots (QDs) stability in aqueous medium was proposed. Hydrophilic CdSe core-shell nanocrystals were synthesized and used with three polymer-based organic stabilizers, two of which contain PEG chains. An increasing of the stability under applied electric field (EF) was shown for stabilizer containing higher amount of PEG chains and terminal amino-groups: introduction of additional PEG chains allowed reducing degradation of luminescence intensity for about 60%. The changes of QDs solutions after EF treatment were examined by dynamic light scattering measurements, luminescence and absorbance spectroscopy, and conductivity measurements and explained by decreasing of quantum yield of the samples due to degradation of stabilizer coating. - Highlights: • Hydrophilic QDs with three types of stabilizer coatings were prepared and treated by electric field in water environment. • Permanent QDs luminescence quenching in aqueous medium under low electric field strength was observed. • Luminescence stability to EF treatment increases by stabilizer with higher PEG content. • Redox mechanism of luminescence quenching was proved via conductivity, DLS, and UV-visible absorbance measurements.

  9. Investigation of Poly(3,4-ethylenedioxythiophene:Poly(styrenesulfonate Hole Transport Layer for Solution-Processed Polymer Solar Cells

    Directory of Open Access Journals (Sweden)

    Chengxi Zhang

    2015-01-01

    Full Text Available The inverted polymer solar cell was prepared by self-made spray-coating system, and the poly(3,4-ethylenedioxythiophene:poly(styrenesulfonate (PEDOT:PSS hole transport layer was studied. 220 nm poly-(3-hexylthiophene:[6,6]-phenylC61butyric-acid methyl-ester (P3HT:PCBM and 40 nm PEDOT:PSS were deposited on ZnO thin film subsequently by solution spray coating. Different volume of isopropyl alcohol was introduced into PEDOT:PSS to decrease the contact angle and obtain the optimum Marangoni flow. The surface morphology and roughness of PEDOT:PSS films were characterized by atomic force microscopy with varied deposition temperature from 70°C to 160°C. The improvement of power conversion efficiency (PCE was attributed to the enhancement of vertical phase separation in PEDOT:PSS film, which improved the charge transfer in the bulk cell. The highest PCE of spray-coated PSCs reached 2.80% after postannealing for 10 min.

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

    Science.gov (United States)

    Yu, You; Yan, Casey; Zheng, Zijian

    2014-08-20

    Metal interconnects, contacts, and electrodes are indispensable elements for most applications of flexible, stretchable, and wearable electronics. Current fabrication methods for these metal conductors are mainly based on conventional microfabrication procedures that have been migrated from Si semiconductor industries, which face significant challenges for organic-based compliant substrates. This Research News highlights a recently developed full-solution processing strategy, polymer-assisted metal deposition (PAMD), which is particularly suitable for the roll-to-roll, low-cost fabrication of high-performance compliant metal conductors (Cu, Ni, Ag, and Au) on a wide variety of organic substrates including plastics, elastomers, papers, and textiles. This paper presents i) the principles of PAMD, and how to use it for making ii) flexible, stretchable, and wearable conductive metal electrodes, iii) patterned metal interconnects, and d) 3D stretchable and compressible metal sponges. A critical perspective on this emerging strategy is also provided. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Amorphous is not always better—A dissolution study on solid state forms of carbamazepine

    DEFF Research Database (Denmark)

    Jensen, Linda G.; Skautrup, Frederik B.; Müllertz, Anette

    2017-01-01

    state forms of carbamazepine, crystalline or amorphous drug, with or without either polyvinylpyrrolidone (PVP) or hydroxypropylmethylcellulose (HPMC) and glass solutions of the drug with both polymers (2:1, 4:1 and 10:1 (w/w) drug-to-polymer ratio) were tested with respect to their dissolution behaviour...... in a biorelevant gastric medium (for 30 min) and subsequently in intestinal conditions (for 2 h). Carbamazepine form III in the absence of polymer dissolved to a drug concentration of 540 μg/ml, but the concentration decreased after around 70 min due to precipitation of the dihydrate form, and reached 436 μg....../ml after 2.5 h dissolution testing. The presence of PVP led to a similar dissolution profile with a slightly earlier onset of decrease in drug concentration, while in the presence of HPMC no decline in dissolved drug concentration was observed. Surprisingly, amorphous carbamazepine did not result in any...

  12. Detecting phase separation of freeze-dried binary amorphous systems using pair-wise distribution function and multivariate data analysis

    DEFF Research Database (Denmark)

    Chieng, Norman; Trnka, Hjalte; Boetker, Johan

    2013-01-01

    The purpose of this study is to investigate the use of multivariate data analysis for powder X-ray diffraction-pair-wise distribution function (PXRD-PDF) data to detect phase separation in freeze-dried binary amorphous systems. Polymer-polymer and polymer-sugar binary systems at various ratios were...... freeze-dried. All samples were analyzed by PXRD, transformed to PDF and analyzed by principal component analysis (PCA). These results were validated by differential scanning calorimetry (DSC) through characterization of glass transition of the maximally freeze-concentrate solute (Tg'). Analysis of PXRD......-PDF data using PCA provides a more clear 'miscible' or 'phase separated' interpretation through the distribution pattern of samples on a score plot presentation compared to residual plot method. In a phase separated system, samples were found to be evenly distributed around the theoretical PDF profile...

  13. Building mechanism for a high open-circuit voltage in an all-solution-processed tandem polymer solar cell.

    Science.gov (United States)

    Kong, Jaemin; Lee, Jongjin; Kim, Geunjin; Kang, Hongkyu; Choi, Youna; Lee, Kwanghee

    2012-08-14

    Additional post-processing techniques, such as post-thermal annealing and UV illumination, were found to be required to obtain desirable values of the cell parameters in a tandem polymer solar cell incorporated with solution-processed basic n-type titanium sub-oxide (TiO(x))/acidic p-type poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) interlayers. Subsequent to the fabrication of the tandem polymer solar cells, the open-circuit voltage (V(OC)) of the cells exhibited half of the expected value. Only after the application of the post-treatments, the V(OC) of a tandem cell increased from the initial half-cell value (∼0.6 V) to its full-cell value (∼1.2 V). The selective light-biased incident photon-to-current efficiency (IPCE) measurements indicated that the initial V(OC) originated from the back subcell and that the application of the post-processing treatments revived the front subcell, such that the net photocurrent of the tandem cell was finally governed by a recombination process of holes from the back subcell and electrons from the front subcell. Based on our experimental results, we suggest that a V(OC) enhancement could be ascribed to two types of subsequent junction formations at the interface between the TiO(x) and PEDOT:PSS interlayers: an 'ion-mediated dipole junction', resulting from the electro-kinetic migration of cationic ions in the interlayers during post-thermal annealing in the presence of a low-work-function metal cathode, and a 'photoinduced Schottky junction', formed by increasing the charge carrier density in the n-type TiO(x) interlayer during UV illumination process. The two junctions separately contributed to the formation of a recombination junction through which the electrons in TiO(x) and the holes in PEDOT:PSS were able to recombine without substantial voltage drops.

  14. Evaluation of conductive polymers as an adsorbent for eradication of As (III from aqueous solution using inductively coupled plasma optical emission spectroscopy (ICP-OES

    Directory of Open Access Journals (Sweden)

    Muhammad Imran Din

    2014-04-01

    Full Text Available 1024x768 The main focused of this research work is the preparation of conductive polymers like polypyrrole, polyaniline and polythiophene and their application as adsorbent materials for the removal of hyper toxic metal As (III from aqueous solution. The metal ions get attached on the π-electrons at the back bone of polymer that illustrate excellent affinity for metal ions. The adsorption of As (II ions was carried out on polythiophene due to its redox properties and the stronger interaction between sulfur atoms with arsenic atoms. To attain large surface area and for maximum interaction of As (III ions with polymers, the particle size of polymers was ranged in nano scale. As the surface area increases with decrease in particle size, the active sites for metal ions also increases. These polymers were characterized by FIIR spectroscopy and SEM analysis. Adsorption isothermal data was examined by two parameters (Langmuir, Freundlich, and Dubinin-Radushkevich and three parameters Redlich-Petrson, Sips and Toth models. Experimental results showed that based on standard deviation (SD and Chi square test (χ2 the experimental data was best explained by Freundlich and Toth isotherm. Thermodynamics parameters such as free energy change (ΔG0, enthalpy change (ΔH0 and entropy change (ΔS0 have been calculated respectively, which revealed the spontaneous, endothermic and feasible nature of adsorption process.   Normal 0 false false false EN-US X-NONE X-NONE

  15. Unusual photoanisotropic alignment in amorphous azobenzene polymers

    DEFF Research Database (Denmark)

    Ramanujam, P.S.

    2015-01-01

    560 and 630nm, where the absorption is minimal, results in a possible uniaxial hedgehog arrangement of the molecules. Experiments performed with a dye laser, which can be tuned continuously between 560 and 630nm, are described. Not only azobenzene but also another photosensitive molecule...

  16. Thermal residual stresses in amorphous thermoplastic polymers

    Science.gov (United States)

    Grassia, Luigi; D'Amore, Alberto

    2010-06-01

    An attempt to calculate the internal stresses in a cylindrically shaped polycarbonate (LEXAN-GE) component, subjected to an arbitrary cooling rate, will be described. The differential volume relaxation arising as a result of the different thermal history suffered by each body point was considered as the primary source of stresses build up [1-3]. A numerical routine was developed accounting for the simultaneous stress and structural relaxation processes and implemented within an Ansys® environment. The volume relaxation kinetics was modeled by coupling the KAHR (Kovacs, Aklonis, Hutchinson, Ramos) phenomenological theory [4] with the linear viscoelastic theory [5-7]. The numerical algorithm translates the specific volume theoretical predictions at each body point as applied non-mechanical loads acting on the component. The viscoelastic functions were obtained from two simple experimental data, namely the linear viscoelastic response in shear and the PVT (pressure volume temperature) behavior. The dimensionless bulk compliance was extracted from PVT data since it coincides with the memory function appearing in the KAHR phenomenological theory [7]. It is showed that the residual stress scales linearly with the logarithm of the Biot's number.

  17. Study on the substrate-induced crystallisation of amorphous SiC-precursor ceramics. TIB/A; Untersuchungen zur substratinduzierten Kristallisation amorpher SiC-Precursorkeramiken

    Energy Technology Data Exchange (ETDEWEB)

    Rau, C.

    2000-12-01

    In the present thesis the crystallization behaviour of amorphous silicon-carbon materials (SiC{sub x}) was studied. The main topic of the experimental studies formed thereby the epitactical crystallization of thin silicon carbide layers on monocrystalline substrates of silicon carbides or silicon. Furthermore by thermolysis of the polymer amorphous SiC{sub x}-powder was obtained.

  18. Processing of thermoplastic polymers using reactive solvents

    NARCIS (Netherlands)

    Meijer, H.E.H.; Venderbosch, R.W.; Goossens, J.G.P.; Lemstra, P.J.

    1996-01-01

    The use of reactive solvents offers an interesting and flexible route to extent the processing characteristics of thermoplastic polymers beyond their existing limits. This holds for both intractable and tractable polymers. The first mainly applies for amorphous high-Tg polymers where processing may

  19. Renewable Resources and a Recycled Polymer as Raw Materials: Mats from Electrospinning of Lignocellulosic Biomass and PET Solutions

    Directory of Open Access Journals (Sweden)

    Rachel Passos de Oliveira Santos

    2018-05-01

    . DMA showed superior values of storage modulus (E’ at 30 °C for the mats characterized in the preferential direction of fiber alignment. For example, for mats obtained from solutions prepared from a 0.4 ratio of sisal fibers/PET, Sisal/PET0.40dir presented a high E’ value of 765 MPa compared to Sisal/PET0.40op that presented an E’ value of 88.4 MPa. The fiber alignment did not influence the Tg values (from tan δ peak of electrospun mats with the same compositions, as they presented similar values for this property. The tensile properties of the electrospun mats were significantly impacted by the alignment of the fibers: e.g., Sisal/PET0.40dir presented a high tensile strength value of 15.72 MPa, and Sisal/PET0.40op presented a value of approximately 2.5 MPa. An opposite trend was observed regarding the values of elongation at break for these materials. Other properties of the mats are also discussed; such as the index of fiber alignment, average porosity, and surface contact angle. To our knowledge, this is the first time that the influence of fiber alignment on the properties of electrospun mats based on untreated lignocellulosic biomass combined with a recycled polymer, such as PET, has been evaluated. The mats obtained in this study have potential for diversified applications, such as reinforcement for polymeric matrices in nanocomposites, membranes for filtration, and support for enzymes, wherein the fiber alignment, together with other evaluated properties, can impact their effectiveness in these applications.

  20. Emerging trends in the stabilization of amorphous drugs

    DEFF Research Database (Denmark)

    Laitinen, Riikka; Löbmann, Korbinian; Strachan, Clare J.

    2013-01-01

    The number of active pharmaceutical substances having high therapeutic potential but low water solubility is constantly increasing, making it difficult to formulate these compounds as oral dosage forms. The solubility and dissolution rate, and thus potentially the bioavailability, of these poorly...... water-soluble drugs can be increased by the formation of stabilized amorphous forms. Currently, formulation as solid polymer dispersions is the preferred method to enhance drug dissolution and to stabilize the amorphous form of a drug. The purpose of this review is to highlight emerging alternative...... of mesoporous silicon and silica-based carriers are presented as potential means to increase the stability of amorphous pharmaceuticals....

  1. Fabrication of amorphous InGaZnO thin-film transistor with solution processed SrZrO3 gate insulator

    Science.gov (United States)

    Takahashi, Takanori; Oikawa, Kento; Hoga, Takeshi; Uraoka, Yukiharu; Uchiyama, Kiyoshi

    2017-10-01

    In this paper, we describe a method of fabrication of thin film transistors (TFTs) with high dielectric constant (high-k) gate insulator by a solution deposition. We chose a solution processed SrZrO3 as a gate insulator material, which possesses a high dielectric constant of 21 with smooth surface. The IGZO-TFT with solution processed SrZrO3 showed good switching property and enough saturation features, i.e. field effect mobility of 1.7cm2/Vs, threshold voltage of 4.8V, sub-threshold swing of 147mV/decade, and on/off ratio of 2.3×107. Comparing to the TFTs with conventional SiO2 gate insulator, the sub-threshold swing was improved by smooth surface and high field effect due to the high dielectric constant of SrZrO3. These results clearly showed that use of solution processed high-k SrZrO3 gate insulator could improve sub-threshold swing. In addition, the residual carbon originated from organic precursors makes TFT performances degraded.

  2. Amorphous iron (II) carbonate

    DEFF Research Database (Denmark)

    Sel, Ozlem; Radha, A.V.; Dideriksen, Knud

    2012-01-01

    Abstract The synthesis, characterization and crystallization energetics of amorphous iron (II) carbonate (AFC) are reported. AFC may form as a precursor for siderite (FeCO3). The enthalpy of crystallization (DHcrys) of AFC is similar to that of amorphous magnesium carbonate (AMC) and more...

  3. Locomotion of Amorphous Surface Robots

    Science.gov (United States)

    Bradley, Arthur T. (Inventor)

    2018-01-01

    An amorphous robot includes a compartmented bladder containing fluid, a valve assembly, and an outer layer encapsulating the bladder and valve assembly. The valve assembly draws fluid from a compartment(s) and discharges the drawn fluid into a designated compartment to displace the designated compartment with respect to the surface. Another embodiment includes elements each having a variable property, an outer layer that encapsulates the elements, and a control unit. The control unit energizes a designated element to change its variable property, thereby moving the designated element. The elements may be electromagnetic spheres with a variable polarity or shape memory polymers with changing shape and/or size. Yet another embodiment includes an elongated flexible tube filled with ferrofluid, a moveable electromagnet, an actuator, and a control unit. The control unit energizes the electromagnet and moves the electromagnet via the actuator to magnetize the ferrofluid and lengthen the flexible tube.

  4. Analysis of water sorption isotherms of amorphous food materials by solution thermodynamics with relevance to glass transition: evaluation of plasticizing effect of water by the thermodynamic parameters.

    Science.gov (United States)

    Shimazaki, Eriko; Tashiro, Akiko; Kumagai, Hitomi; Kumagai, Hitoshi

    2017-04-01

    Relation between the thermodynamic parameters obtained from water sorption isotherms and the degree of reduction in the glass transition temperature (T g ), accompanied by water sorption, was quantitatively studied. Two well-known glassy food materials namely, wheat gluten and maltodextrin were used as samples. The difference between the chemical potential of water in a solution and that of pure water ([Formula: see text]), the difference between the chemical potential of solid in a solution and that of a pure solid ([Formula: see text]), and the change in the integral Gibbs free energy ([Formula: see text]) were obtained by analyzing the water sorption isotherms using solution thermodynamics. The parameter [Formula: see text] correlated well with ΔT g (≡T g  - T g0 ; where T g0 is the glass transition temperature of dry material), which had been taken to be an index of plasticizing effect. This indicates that plasticizing effect of water on foods can be evaluated through the parameter [Formula: see text].

  5. Solvent-dependent self-assembly and ordering in slow-drying semi-crystalline conjugated polymer solutions

    KAUST Repository

    Zhao, Kui; Yu, Xinhong; Li, Ruipeng; Amassian, Aram; Han, Yanchun

    2015-01-01

    The mechanistic understanding of the intrinsic molecular self-assembly of conjugated polymers is of immense importance to controlling the microstructure development in organic semiconducting thin films, with meaningful impact on charge transport

  6. Hydrogen in amorphous silicon

    International Nuclear Information System (INIS)

    Peercy, P.S.

    1980-01-01

    The structural aspects of amorphous silicon and the role of hydrogen in this structure are reviewed with emphasis on ion implantation studies. In amorphous silicon produced by Si ion implantation of crystalline silicon, the material reconstructs into a metastable amorphous structure which has optical and electrical properties qualitatively similar to the corresponding properties in high-purity evaporated amorphous silicon. Hydrogen studies further indicate that these structures will accomodate less than or equal to 5 at.% hydrogen and this hydrogen is bonded predominantly in a monohydride (SiH 1 ) site. Larger hydrogen concentrations than this can be achieved under certain conditions, but the excess hydrogen may be attributed to defects and voids in the material. Similarly, glow discharge or sputter deposited amorphous silicon has more desirable electrical and optical properties when the material is prepared with low hydrogen concentration and monohydride bonding. Results of structural studies and hydrogen incorporation in amorphous silicon were discussed relative to the different models proposed for amorphous silicon

  7. A salt water battery with high stability and charging rates made from solution processed conjugated polymers with polar side chains

    KAUST Repository

    Moia, Davide; Giovannitti, Alexander; Szumska, Anna A.; Schnurr, Martin; Rezasoltani, Elham; Maria, Iuliana P.; Barnes, Piers R. F.; McCulloch, Iain; Nelson, Jenny

    2017-01-01

    conjugated polymer backbones, allowed the films to maintain constant capacity at high charge and discharge rates (>1000 C-rate). The electrodes also show good stability during electrochemical cycling (less than 30% decrease in capacity over >1000 cycles) and an output voltage up to 1.4 V. The performance of these semiconducting polymers with polar side-chains demonstrates the potential of this material class for fast-charging, water based electrochemical energy storage devices.

  8. 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...

  9. High-Performance Solution-Processed Amorphous InGaZnO Thin Film Transistors with a Metal–Organic Decomposition Method

    Directory of Open Access Journals (Sweden)

    Yingtao Xie

    2018-01-01

    Full Text Available A facile solution process was introduced for the preparation of IGZO thin films via a metal–organic decomposition (MOD method. The IGZO ink was synthesized by mixing the solutions of gallium acetylacetonate [Ga(C5H7O23], zinc acetylacetonate hydrate [Zn(C5H7O22·xH2O] dissolved in ethanol, and indium acetylacetonate [In(C5H7O23] dissolved in tetrahydrofuran (THF. The deposited films by spin-coating were annealed at moderate process temperature (≤500°C. The relationship between device performance and postannealing temperature was studied. The result demonstrated that mobility of IGZO TFT increased as the annealing temperature increased. Based on the analysis of O 1s statement, the annealing temperature can influence the number of oxygen vacancy to further affect the carrier centration. In addition, the IGZO TFT devices with various Ga molar ratios were compared to demonstrate the influence of the Ga addition. The result demonstrated that the saturated mobilities (μe decreased and VTH shifted to positive voltage as the Ga molar ratio was increased. It is likely that Ga can offer stronger chemical bonds between metal and oxygen that reduced the concentration of free carriers and thus help reducing VTH. As a result, the optimized performance of IGZO TFT with the mobility of 3.4 cm2V−1s−1 showed the MOD process was a promising approach.

  10. Physics of amorphous metals

    CERN Document Server

    Kovalenko, Nikolai P; Krey, Uwe

    2008-01-01

    The discovery of bulk metallic glasses has led to a large increase in the industrial importance of amorphous metals, and this is expected to continue. This book is the first to describe the theoretical physics of amorphous metals, including the important theoretical development of the last 20 years.The renowned authors stress the universal aspects in their description of the phonon or magnon low-energy excitations in the amorphous metals, e.g. concerning the remarkable consequences of the properties of these excitations for the thermodynamics at low and intermediate temperatures. Tunneling

  11. Characterization of proton conducting blend polymer electrolyte using PVA-PAN doped with NH{sub 4}SCN

    Energy Technology Data Exchange (ETDEWEB)

    Premalatha, M. [PG & Research Department of Physics, N.M.S.S.Vellaichamy Nadar College, Madurai-625 019 (India); Materials Research Center, Coimbatore-641 045 (India); Mathavan, T., E-mail: tjmathavan@gmail.com, E-mail: kingslin.genova20@gmail.com [PG & Research Department of Physics, N.M.S.S.Vellaichamy Nadar College, Madurai-625 019 (India); Selvasekarapandian, S. [Materials Research Center, Coimbatore-641 045 (India); Genova, F. Kingslin Mary, E-mail: tjmathavan@gmail.com, E-mail: kingslin.genova20@gmail.com; Umamaheswari, R. [Department of physics, S.F.R College for Women, Sivakasi-626 128 (India)

    2016-05-23

    Polymer electrolytes with proton conductivity based on blend polymer using polyvinyl alcohol (PVA) and poly acrylo nitrile (PAN) doped with ammonium thiocyanate have been prepared by solution casting method using DMF as solvent. The complex formation between the blend polymer and the salt has been confirmed by FTIR Spectroscopy. The amorphous nature of the blend polymer electrolytes have been confirmed by XRD analysis. The highest conductivity at 303 K has been found to be 3.25 × 10{sup −3} S cm{sup −1} for 20 mol % NH{sub 4}SCN doped 92.5PVA:7.5PAN system. The increase in conductivity of the doped blend polymer electrolytes with increasing temperature suggests the Arrhenius type thermally activated process. The activation energy is found to be low (0.066 eV) for the highest conductivity sample.

  12. Definition and properties of ideal amorphous structures

    International Nuclear Information System (INIS)

    Stachurski, Z.H.

    2002-01-01

    Full text: Amorphous structure is usually defined by what it is not (ie, no crystalline peaks in XRS, no bond correlation in NMR), rather than by what it is. The interest in defining the structure of non-crystalline materials is long standing; packing geometry of spheres, molecular structure of glassy SiO 2 , or the structure of atactic polymers are prime examples. The earliest definitions of amorphous structure were in terms of a microcrystallite model of Valenkov, or continuous random network by Zachariasen. The random close packing of spheres of equal size, and an amorphous structure, composed of freely jointed linear chains of hard spheres, has been described mathematically in terms of a linear homogeneous Poisson process. This paper aims to describe some geometrical, kinematic, and topological properties of these two ideal amorphous structures, which belong to the same amorphous class. The geometry of packing is elucidated, and the use of Voronoi tessellation method for measuring the structures is described. The ideal amorphous solid has no symmetry elements; its volume can not be divided into identical unit cells. However, there is a volume element small enough to allow the distinction of its nanoscopic inhomogeneities, and sufficiently large enough to represent, accurately the overall behaviour. We define this volume element, the representative volume element. Suitable boundary conditions must be prescribed for a choice of RVE, and satisfy certain requirements. Topologically, a catchment region on the Born-Oppenheimer potential energy surface over nuclear configuration space, is defined by Mezey and Bader as an energetically stable geometry of the open region of R 3 traversed by all the trajectories which terminate at a local maximum. Two topological properties will be described: (i) the boundaries of the catchment region as a direct geometrical correspondence to the Voronoi polyhedron for a given atom in a given structure, and (ii) the constriction points

  13. Improvement of bias-stability in amorphous-indium-gallium-zinc-oxide thin-film transistors by using solution-processed Y{sub 2}O{sub 3} passivation

    Energy Technology Data Exchange (ETDEWEB)

    An, Sungjin; Mativenga, Mallory; Kim, Youngoo; Jang, Jin, E-mail: jjang@khu.ac.kr [Advanced Display Research Center, Department of Information Display, Kyung Hee University, Dongdaemun-gu, Seoul 130-701 (Korea, Republic of)

    2014-08-04

    We demonstrate back channel improvement of back-channel-etch amorphous-indium-gallium-zinc-oxide (a-IGZO) thin-film transistors by using solution-processed yttrium oxide (Y{sub 2}O{sub 3}) passivation. Two different solvents, which are acetonitrile (35%) + ethylene glycol (65%), solvent A and deionized water, solvent B are investigated for the spin-on process of the Y{sub 2}O{sub 3} passivation—performed after patterning source/drain (S/D) Mo electrodes by a conventional HNO{sub 3}-based wet-etch process. Both solvents yield devices with good performance but those passivated by using solvent B exhibit better light and bias stability. Presence of yttrium at the a-IGZO back interface, where it occupies metal vacancy sites, is confirmed by X-ray photoelectron spectroscopy. The passivation effect of yttrium is more significant when solvent A is used because of the existence of more metal vacancies, given that the alcohol (65% ethylene glycol) in solvent A may dissolve the metal oxide (a-IGZO) through the formation of alkoxides and water.

  14. Positrons in amorphous alloys

    International Nuclear Information System (INIS)

    Moser, Pierre.

    1981-07-01

    Positron annihilation techniques give interesting informations about ''empty spaces'' in amorphous alloys. The results of an extensive research work on the properties of either pre-existing or irradiation induced ''empty spaces'' in four amorphous alloys are presented. The pre-existing empty spaces appear to be small vacancy-like defects. The irradiation induced defects are ''close pairs'' with widely distributed configurations. There is a strong interaction between vacancy like and interstitial like components. A model is proposed, which explains the radiation resistance mechanism of the amorphous alloys. An extensive joint research work to study four amorphous alloys, Fe 80 B 20 ,Fe 40 Ni 40 P 14 B 6 , Cu 50 Ti 50 , Pd 80 Si 20 , is summarized

  15. Facile construction of terpridine-based metallo-polymers in hydrogels, crystals and solutions directed by metal ions.

    Science.gov (United States)

    Li, Yajuan; Guo, Jiangbo; Dai, Bo; Geng, Lijun; Shen, Fengjuan; Zhang, Yajun; Yu, Xudong

    2018-07-01

    Driven by tunable metal-ligand interactions, a polydentate ligand TC containing terpyridine and carboxylic acid units was developed to construct metallo-polymers that showed multiple aggregation modes with controlled macroscopic properties. In the presence of different kind of Zn 2+ ions or NaOH, TC could form metallo-polymers via π-π stacking and metal-ligand interaction that further trapped water molecules, resulting in hydrogels and crystals. Moreover, these TC/Zn 2+ hydrogels could transform to soluble and fluorescent aggregates in the presence of NaOH due to the formation of binuclear metallo-polymers with enhanced ICT emission. The metal-ligand interactions tuned by different metal salts in gels, crystals, and sols were also studied and illustrated in detail, it was also proved that water was an essential linker for constructing Na + -based metallo-polymers from the TC/NaOH crystal data. This work demonstrated the engineered coordination pathways in generating controllable hydrogels and metallo-polymers for the first time, which led to novel approach for facilely constructing a number of hydrogels with tailorable macroscopic properties. Copyright © 2018 Elsevier Inc. All rights reserved.

  16. Superplasticity of amorphous alloy

    International Nuclear Information System (INIS)

    Levin, Yu.B.; Likhachev, V.L.; Sen'kov, O.N.

    1988-01-01

    Results of mechanical tests of Co 57 Ni 10 Fe 5 Si 11 B 17 amorphous alloy are presented and the effect of crystallization, occurring during deformation process, on plastic low characteristics is investiagted. Superplasticity of amorphous tape is investigated. It is shown, that this effect occurs only when during deformation the crystallization takes place. Process model, based on the usage disclination concepts about glass nature, is suggested

  17. Amorphous and Crystalline Particulates: Challenges and Perspectives in Drug Delivery.

    Science.gov (United States)

    Al-Obaidi, Hisham; Majumder, Mridul; Bari, Fiza

    2017-01-01

    Crystalline and amorphous dispersions have been the focus of academic and industrial research due to their potential role in formulating poorly water-soluble drugs. This review looks at the progress made starting with crystalline carriers in the form of eutectics moving towards more complex crystalline mixtures. It also covers using glassy polymers to maintain the drug as amorphous exhibiting higher energy and entropy. However, the amorphous form tends to recrystallize on storage, which limits the benefits of this approach. Specific interactions between the drug and the polymer may retard this spontaneous conversion of the amorphous drug. Some studies have shown that it is possible to maintain the drug in the amorphous form for extended periods of time. For the drug and the polymer to form a stable mixture they have to be miscible on a molecular basis. Another form of solid dispersions is pharmaceutical co-crystals, for which research has focused on understanding the chemistry, crystal engineering and physico-chemical properties. USFDA has issued a guidance in April 2013 suggesting that the co-crystals as a pharmaceutical product may be a reality; but just not yet! While some of the research is still oriented towards application of these carriers, understanding the mechanism by which drug-carrier miscibility occurs is also covered. Within this context is the use of thermodynamic models such as Flory-Huggins model with some examples of studies used to predict miscibility. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  18. Characterization of amorphous and nanocrystalline carbon films

    International Nuclear Information System (INIS)

    Chu, Paul K.; Li Liuhe

    2006-01-01

    Amorphous and nanocrystalline carbon films possess special chemical and physical properties such as high chemical inertness, diamond-like properties, and favorable tribological proprieties. The materials usually consist of graphite and diamond microstructures and thus possess properties that lie between the two. Amorphous and nanocrystalline carbon films can exist in different kinds of matrices and are usually doped with a large amount of hydrogen. Thus, carbon films can be classified as polymer-like, diamond-like, or graphite-like based on the main binding framework. In order to characterize the structure, either direct bonding characterization methods or the indirect bonding characterization methods are employed. Examples of techniques utilized to identify the chemical bonds and microstructure of amorphous and nanocrystalline carbon films include optical characterization methods such as Raman spectroscopy, Ultra-violet (UV) Raman spectroscopy, and infrared spectroscopy, electron spectroscopic and microscopic methods such as scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy, transmission electron microscopy, and electron energy loss spectroscopy, surface morphology characterization techniques such as scanning probe microscopy (SPM) as well as other characterization methods such as X-ray reflectivity and nuclear magnetic resonance. In this review, the structures of various types of amorphous carbon films and common characterization techniques are described

  19. Study of amorphous semiconductors doped with rare earths (Gd and Er) and conducting polymers by EPR techniques and magnetic susceptibility; Estudo de semicondutores amorfos dopados com terras raras (Gd e Er) e de polimeros condutores atraves das tecnicas de RPE e susceptibilidade magnetica

    Energy Technology Data Exchange (ETDEWEB)

    Sercheli, Mauricio da Silva

    1999-07-01

    This thesis involves the study of amorphous semiconductors and conducting polymers, which have been characterized by EPR and magnetic susceptibility measurements, and to a lesser extent by Raman spectroscopy and RBS. The semiconductors were studied using thin films of silicon doped with rare earth metals, e.g. erbium and gadolinium, which had their magnetic properties studied. Using these studies we could determine the state of valence of the rare earths as well as their concentrations in the silicon matrix. According to our results, the valence of the rare earth metal ions is 3+, and we were able to conclude that 4f electronic shells could not be used for the calculation of the conducting band in this system. Furthermore, the analysis of the data on the magnetic susceptibility of the Er{sup 3+} ion with cubic crystalline acting field, gave us the opportunity to estimate the overall splitting of their electronic states for the first time. The conducting polymers were studied using samples of poly(3-methylthiophene) doped with ClO{sub 4}{sup -}, which show a phase transition in the range of 230 K to 130 K. The electron paramagnetic resonance also gives important information on the crystallization, doping level and the presence of polarons or bipolarons in conducting polymers. (author)

  20. Amorphous V-O-C composite nanofibers electrospun from solution precursors as binder- and conductive additive-free electrodes for supercapacitors with outstanding performance

    Science.gov (United States)

    Chen, Xia; Zhao, Bote; Cai, Yong; Tadé, Moses O.; Shao, Zongping

    2013-11-01

    Flexible V-O-C composite nanofibers were fabricated from solution precursors via electrospinning and were investigated as free-standing and additive-free film electrodes for supercapacitors. Specifically, composite nanofibers (V0, V5, V10 and V20) with different vanadyl acetylacetonate (VO(acac)2) contents of 0, 5, 10 and 20 wt% with respect to polyacrylonitrile (PAN) were prepared. The composite nanofibers were comparatively studied using XRD, Raman spectroscopy, XPS, N2 adsorption-desorption, FE-SEM, TEM and S-TEM. The vanadium element was found to be well-dispersed in the carbon nanofibers, free from the formation of an aggregated crystalline phase, even in the case of V20. A specific surface area of 587.9 m2 g-1 was reached for V10 after calcination, which is approximately twice that of the vanadium-free carbon nanofibers (V0, 300.9 m2 g-1). To perform as an electrode for supercapacitors in an aqueous electrolyte, the V10 film delivered a specific capacitance of 463 F g-1 at 1 A g-1. V10 was also able to retain a specific capacitance of 380 F g-1, even at a current density of 10 A g-1. Additionally, very stable cycling stability was achieved, maintaining an outstanding specific capacitance of 400 F g-1 at 5 A g-1 after charge-discharge cycling 5000 times. Thus, V-O-C composite nanofibers are highly attractive electrode materials for flexible, high-power, thin film energy storage devices and applications.Flexible V-O-C composite nanofibers were fabricated from solution precursors via electrospinning and were investigated as free-standing and additive-free film electrodes for supercapacitors. Specifically, composite nanofibers (V0, V5, V10 and V20) with different vanadyl acetylacetonate (VO(acac)2) contents of 0, 5, 10 and 20 wt% with respect to polyacrylonitrile (PAN) were prepared. The composite nanofibers were comparatively studied using XRD, Raman spectroscopy, XPS, N2 adsorption-desorption, FE-SEM, TEM and S-TEM. The vanadium element was found to be well

  1. Investigation of the degradation and stability of acrylamide-based polymers in acid solution: Functional monomer modified polyacrylamide

    Directory of Open Access Journals (Sweden)

    Yuxin Pei

    2016-12-01

    Full Text Available Acrylamide copolymers are often used as acidizing diverting and thickening agents for their advantageous thickening, flocculation, adhesion and resistance reduction properties. Experimental results indicate that the acid concentration greatly affects the properties of acrylamide polymers, which varies from results reported by other researchers. Considering the theoretical and field application value of the present study, four comparable acrylamide-based polymers were synthesized, and their macro- and micro-changes as well as the related changes in viscosity and molecular weight were studied in high-concentration hydrochloric acid. A proposed mechanism of acrylamide copolymer stability and degradation is provided, and further suggestions are made for the modification of acrylamide copolymers.

  2. Reduction in Friction and Wear of Alumina Surfaces as Assisted with Surface-Adsorbing Polymers in Aqueous Solutions

    DEFF Research Database (Denmark)

    Røn, Troels; Lee, Seunghwan

    2016-01-01

    We have investigated the aqueous lubricating effects of various polymers for the sliding contacts of self-mated alumina surfaces in neutral aqueous environment. Given that isoelectric point (IEP) of alumina is ca. pH 9, polyanions can readily adsorb onto alumina surface at neutral pH via electros......We have investigated the aqueous lubricating effects of various polymers for the sliding contacts of self-mated alumina surfaces in neutral aqueous environment. Given that isoelectric point (IEP) of alumina is ca. pH 9, polyanions can readily adsorb onto alumina surface at neutral pH via...

  3. Corrosion behavior of amorphous and crystalline Cu50Ti50 and Cu50Zr50 alloys

    International Nuclear Information System (INIS)

    Naka, M.; Hoshimoto, K.; Masumoto, T.

    1978-01-01

    Corrosion rates and anodic polarization curves of amorphous and crystalline Cu 50 Ti 50 and Cu 50 Zr 50 alloys have been examined in various acidic, neutral and alkaline solutions. The amorphous alloys are very stable in acidic and alkaline solutions, but unstable in agressive chloride solutions. The corrosion resistance of these amorphous alloys is higher than that of the crystallized alloys. The high corrosion resistance of amorphous alloys is attributable to the high chemical homogeneity of amorphous alloys without localized crystalline defects such as precipitates, segregates, grain boundaries, etc. Metalloid elements play an important role in the corrosion behavior of amorphous alloys; the addition of phosphorus to amorphous Cu-Ti alloy greatly increases the corrosion resistance, even in 1N HCl. (Auth.)

  4. A universal route to fabricate n-i-p multi-junction polymer solar cells via solution processing

    NARCIS (Netherlands)

    Rasi, Dario Di Carlo; Hendriks, Koen H.; Heintges, Gael H. L.; Simone, Giulio; Gelinck, Gerwin H.; Gevaerts, Veronique S.; Andriessen, Ronn; Pirotte, Geert; Maes, Wouter; Li, Weiwei; Wienk, Martijn M.; Janssen, Rene A. J.

    The interconnection layer (ICL) that connects adjacent subcells electrically and optically in solution‐processed multi‐junction polymer solar cells must meet functional requirements in terms of work functions, conductivity, and transparency, but also be compatible with the multiple layer stack in

  5. Vapour–Liquid Equilibria in the Polymer + Solvent System Containing Lower Concentrations of Solute at Normal or Reduced Pressures

    Czech Academy of Sciences Publication Activity Database

    Pavlíček, Jan; Bogdanić, Grozdana; Wichterle, Ivan

    2013-01-01

    Roč. 358, 25 NOV (2013), s. 301-303 ISSN 0378-3812 Institutional support: RVO:67985858 Keywords : vapour–liquid equilibrium * experimental data * polymer-solvent system Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.241, year: 2013

  6. Driving High-Performance n- and p-type Organic Transistors with Carbon Nanotube/Conjugated Polymer Composite Electrodes Patterned Directly from Solution

    KAUST Repository

    Hellstrom, Sondra L.

    2010-07-12

    We report patterned deposition of carbon nanotube/conjugated polymer composites from solution with high nanotube densities and excellent feature resolution. Such composites are suited for use as electrodes in high-performance transistors of pentacene and C60, with bottom-contact mobilities of ?0.5 and ?1 cm2 V-1 s-1, respectively. This represents a clear step towards development of inexpensive, high-performance all-organic circuits. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Solution-Processed rGO/AgNPs/rGO Sandwich Structure as a Hole Extraction Layer for Polymer Solar Cells

    Directory of Open Access Journals (Sweden)

    Quang Trung Tran

    2015-01-01

    Full Text Available We found that inserting silver nanoparticles (AgNPs between two layers of reduced grapheme oxide (rGO has an effect on tailoring the work function of rGO. The utilization of rGO/AgNPs/rGO sandwich structure as the hole extraction layer in polymer solar cells is demonstrated. Solution-processable fabrication of this sandwich structure at the ITO/active layer interface facilitates the extraction of hole from active layer into ITO anode because of lowering the barrier level alignment at the interface. It results in an improvement of the short circuit current density and the overall photovoltaic performance.

  8. Infrared spectroscopic studies of uranyl(VI) species adsorbed from aqueous [UO2(CO3)3]4- solutions on to a polymer bearing amidoxime groups

    International Nuclear Information System (INIS)

    Hirotsu, Takahiro; Katoh, Shunsaku; Sugasaka, Kazuhiko; Seno, Manabu; Itagaki, Takaharu

    1987-01-01

    Infrared spectra of uranyl(VI) species adsorbed from aqeuous [UO 2 (CO 3 ) 3 ] 4- solutions on to a polymer having amidoxime groups were examined in order to obtain information on the adsorption mechanism. The subtraction spectra in a region of 500-1 500 cm -1 exhibit only a distinct band at 886 cm -1 ascribed to the v 3 mode of the O=U=O moiety and no band assigned to carbonato ligands, suggesting the existence of a carbonato-free uranyl(VI) complex; this is consistent with the adsorption equilibrium reported previously. (author)

  9. Changes in the Spectral Features of Zinc Phthalocyanine Induced by Nitrogen Dioxide Gas in Solution and in Solid Polymer Nanofiber Media.

    Science.gov (United States)

    Zugle, Ruphino; Tetteh, Samuel

    2017-03-01

    The changes in the spectral features of zinc phthalocyanine in the visible domain as a result of its interaction with nitrogen dioxide gas were assessed in this work. This was done both in solution and when the phthalocyanine was incorporated into a solid polystyrene polymer nanofiber matrix. The spectral changes were found to be spontaneous and marked in both cases suggesting a rapid response criterion for the detection of the gas. In particular, the functionalised nano-fabric material could serve as a practical fire alarm system as it rapidly detects the nitrogen dioxide gas generated during burning.

  10. Indium-Free PTB7/PC71BM Polymer Solar Cells with Solution-Processed Al:ZnO Electrodes on PET Substrates

    Directory of Open Access Journals (Sweden)

    P. Fuchs

    2016-01-01

    Full Text Available Inverted PTB7/PC71BM polymer solar cells are prepared on solution-processed Al:ZnO transparent contacts on PET substrates. Al:ZnO is deposited by a low temperature chemical bath deposition route (T < 100°C at any step to comply with the temperature sensitive substrate. A maximum conversion efficiency of 6.4% and 6.9% is achieved for the indium-free solar cells on PET and glass substrates, respectively. The devices are relatively stable in air whereby an initial efficiency loss in the order of 15% after storage for 15 days can be fully recovered by light soaking.

  11. Characterization of Amorphous and Co-Amorphous Simvastatin Formulations Prepared by Spray Drying

    Directory of Open Access Journals (Sweden)

    Goedele Craye

    2015-12-01

    Full Text Available In this study, spray drying from aqueous solutions, using the surface-active agent sodium lauryl sulfate (SLS as a solubilizer, was explored as a production method for co-amorphous simvastatin–lysine (SVS-LYS at 1:1 molar mixtures, which previously have been observed to form a co-amorphous mixture upon ball milling. In addition, a spray-dried formulation of SVS without LYS was prepared. Energy-dispersive X-ray spectroscopy (EDS revealed that SLS coated the SVS and SVS-LYS particles upon spray drying. X-ray powder diffraction (XRPD and differential scanning calorimetry (DSC showed that in the spray-dried formulations the remaining crystallinity originated from SLS only. The best dissolution properties and a “spring and parachute” effect were found for SVS spray-dried from a 5% SLS solution without LYS. Despite the presence of at least partially crystalline SLS in the mixtures, all the studied formulations were able to significantly extend the stability of amorphous SVS compared to previous co-amorphous formulations of SVS. The best stability (at least 12 months in dry conditions was observed when SLS was spray-dried with SVS (and LYS. In conclusion, spray drying of SVS and LYS from aqueous surfactant solutions was able to produce formulations with improved physical stability for amorphous SVS.

  12. Characterization of Amorphous and Co-Amorphous Simvastatin Formulations Prepared by Spray Drying.

    Science.gov (United States)

    Craye, Goedele; Löbmann, Korbinian; Grohganz, Holger; Rades, Thomas; Laitinen, Riikka

    2015-12-03

    In this study, spray drying from aqueous solutions, using the surface-active agent sodium lauryl sulfate (SLS) as a solubilizer, was explored as a production method for co-amorphous simvastatin-lysine (SVS-LYS) at 1:1 molar mixtures, which previously have been observed to form a co-amorphous mixture upon ball milling. In addition, a spray-dried formulation of SVS without LYS was prepared. Energy-dispersive X-ray spectroscopy (EDS) revealed that SLS coated the SVS and SVS-LYS particles upon spray drying. X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) showed that in the spray-dried formulations the remaining crystallinity originated from SLS only. The best dissolution properties and a "spring and parachute" effect were found for SVS spray-dried from a 5% SLS solution without LYS. Despite the presence of at least partially crystalline SLS in the mixtures, all the studied formulations were able to significantly extend the stability of amorphous SVS compared to previous co-amorphous formulations of SVS. The best stability (at least 12 months in dry conditions) was observed when SLS was spray-dried with SVS (and LYS). In conclusion, spray drying of SVS and LYS from aqueous surfactant solutions was able to produce formulations with improved physical stability for amorphous SVS.

  13. Electrochemical synthesis of novel polymer based on (4-(2,3-dihydrothieno[3,4-6][1,4][dioxin-5-yl) aniline) in aqueous solution: Characterization and application

    International Nuclear Information System (INIS)

    Shahhosseini, Leyla; Nateghi, Mohammad Reza; Kazemipour, Maryam; Borhani Zarandi, Mahmoud

    2016-01-01

    4-(2,3-dihydrothieno[3,4-6][1,4][dioxin-5-yl) aniline, an interesting novel monomer was successfully synthesized in which α-carbon on ethylenedioxythiophene was linked to aniline at para position. The structure of the monomer was approved by infrared (IR), gas chromatography-mass spectrometry (GC-MS) and "1H nuclear magnetic resonance ("1H NMR) spectroscopies. Poly (4-(2,3-dihydrothieno[3,4-6][1,4][dioxin-5-yl) aniline) and its composite with graphene were electrochemically synthesized in aqueous solution by cyclic potential sweep method. The Polymer was characterized by IR and UV–vis spectroscopies, scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy techniques. Electrochemical synthesis conditions were optimized to prepare high conducting and porous polymer so it can be efficiently used as a counter electrode in fabrication of dye sensitized solar cells. Photovoltaic experiments revealed that energy conversion efficiency of the solar cell fabricated using polymer composite (7.52%) is 21% greater than that prepared by Pt counter electrode (6.19%). - Highlights: • A Novel monomer comprising aniline and EDOT was synthesized by a simple process. • Poly (ANI-EDOT) was synthesized and characterized by cyclic potential sweep method. • The copolymer changes from yellow at −0.9 V to dark green color at +0.9 V reversibly. • Poly (ANI-EDOT)/graphene is porous with electrocatalytic effect on I_3"− reduction.

  14. Structural changes in amorphous organic compounds and their role during chemical transformations

    International Nuclear Information System (INIS)

    Gusakovskaya, I.G.

    1994-01-01

    Using butanediol vinylacetate and dimetacrylate as an example, it can be shown that structural changes of amorphous-liquid substance play an important part at chemical transformations of amorphous compounds and chemical reaction rate provides an function of local order. When the amorphous polymer is viewed as an system of multiple transformations, each gives birth to the definite local order, the calculation of recombination reaction of active centers accumulated during irradiation of polymer at 77 K is carried out. Concentration of recombinated centers rises steeply near each transformation T k

  15. Relating hydrogen-bonding interactions with the phase behavior of naproxen/PVP K 25 solid dispersions: evaluation of solution-cast and quench-cooled films.

    Science.gov (United States)

    Paudel, Amrit; Nies, Erik; Van den Mooter, Guy

    2012-11-05

    In this work, we investigated the relationship between various intermolecular hydrogen-bonding (H-bonding) interactions and the miscibility of the model hydrophobic drug naproxen with the hydrophilic polymer polyvinylpyrrolidone (PVP) across an entire composition range of solid dispersions prepared by quasi-equilibrium film casting and nonequilibrium melt quench cooling. The binary phase behavior in solid dispersions exhibited substantial processing method dependence. The solid state solubility of crystalline naproxen in PVP to form amorphous solid dispersions was 35% and 70% w/w naproxen in solution-cast films and quench-cooled films, respectively. However, the presence of a single mixed phase glass transition indicated the amorphous miscibility to be 20% w/w naproxen for the films, beyond which amorphous-amorphous and/or crystalline phase separations were apparent. This was further supported by the solution state interactions data such as PVP globular size distribution and solution infrared spectral profiles. The borderline melt composition showed cooling rate dependence of amorphization. The glass transition and melting point depression profiles of the system were treated with the analytical expressions based on Flory-Huggins mixing theory to interpolate the equilibrium solid solubility. FTIR analysis and subsequent spectral deconvolution revealed composition and miscibility dependent variations in the strength of drug-polymer intermolecular H-bonding. Two types of H-bonded populations were evidenced from 25% w/w and 35% w/w naproxen in solution-cast films and quench-cooled films, respectively, with the higher fraction of strongly H-bonded population in the drug rich domains of phase separated amorphous film compositions and highly drug loaded amorphous quench-cooled dispersions.

  16. Sm-doped CeO2 single buffer layer for YBCO coated conductors by polymer assisted chemical solution deposition (PACSD) method

    International Nuclear Information System (INIS)

    Li, G.; Pu, M.H.; Sun, R.P.; Wang, W.T.; Wu, W.; Zhang, X.; Yang, Y.; Cheng, C.H.; Zhao, Y.

    2008-01-01

    An over 150 nm thick Sm 0.2 Ce 0.8 O 1.9-x (SCO) single buffer layer has been deposited on bi-axially textured NiW (2 0 0) alloy substrate. Highly in-plane and out-of-plane oriented, dense, smooth and crack free SCO single layer has been obtained via a polymer-assisted chemical solution deposition (PACSD) approach. YBCO thin film has been deposited equally via a PACSD route on the SCO-buffered NiW, the as grown YBCO yielding a sharp transition at T c0 = 87 K as well as J c (0 T, 77 K) ∼ 1 MA/cm 2 . These results indicates that RE (lanthanides other than Ce) doping may be an effective approach to improve the critical thickness of solution derived CeO 2 film, which renders it a promising candidate as single buffer layer for YBCO coated conductors

  17. Structural amorphous steels

    International Nuclear Information System (INIS)

    Lu, Z.P.; Liu, C.T.; Porter, W.D.; Thompson, J.R.

    2004-01-01

    Recent advancement in bulk metallic glasses, whose properties are usually superior to their crystalline counterparts, has stimulated great interest in fabricating bulk amorphous steels. While a great deal of effort has been devoted to this field, the fabrication of structural amorphous steels with large cross sections has remained an alchemist's dream because of the limited glass-forming ability (GFA) of these materials. Here we report the discovery of structural amorphous steels that can be cast into glasses with large cross-section sizes using conventional drop-casting methods. These new steels showed interesting physical, magnetic, and mechanical properties, along with high thermal stability. The underlying mechanisms for the superior GFA of these materials are discussed

  18. A Molecular-Level View of the Physical Stability of Amorphous Solid Dispersions

    Science.gov (United States)

    Yuan, Xiaoda

    Many pharmaceutical compounds being developed in recent years are poorly soluble in water. This has led to insufficient oral bioavailability of many compounds in vitro. The amorphous formulation is one of the promising techniques to increase the oral bioavailability of these poorly water-soluble compounds. However, an amorphous drug substance is inherently unstable because it is a high energy form. In order to increase the physical stability, the amorphous drug is often formulated with a suitable polymer to form an amorphous solid dispersion. Previous research has suggested that the formation of an intimately mixed drug-polymer mixture contributes to the stabilization of the amorphous drug compound. The goal of this research is to better understand the role of miscibility, molecular interactions and mobility on the physical stability of amorphous solid dispersions. Methods were developed to detect different degrees of miscibility on nanometer scale and to quantify the extent of hydrogen-bonding interactions between the drug and the polymer. Miscibility, hydrogen-bonding interactions and molecular mobility were correlated with physical stability during a six-month period using three model systems. Overall, this research provides molecular-level insights into many factors that govern the physical stability of amorphous solid dispersions which can lead to a more effective design of stable amorphous formulations.

  19. Polymer Solar Cells with Efficiency >10% Enabled via a Facile Solution-Processed Al-Doped ZnO Electron Transporting Layer

    KAUST Repository

    Jagadamma, Lethy Krishnan

    2015-04-22

    A facile and low-temperature (125 °C) solution-processed Al-doped ZnO (AZO) buffer layer functioning very effectively as electron accepting/hole blocking layer for a wide range of polymer:fullerene bulk heterojunction systems, yielding power conversion efficiency in excess of 10% (8%) on glass (plastic) substrates is described. The ammonia-treatment of the aqueous AZO nanoparticle solution produces compact, crystalline, and smooth thin films, which retain the aluminum doping, and eliminates/reduces the native defects by nitrogen incorporation, making them good electron transporters and energetically matched with the fullerene acceptor. It is demonstrated that highly efficient solar cells can be achieved without the need for additional surface chemical modifications of the buffer layer, which is a common requirement for many metal oxide buffer layers to yield efficient solar cells. Also highly efficient solar cells are achieved with thick AZO films (>50 nm), highlighting the suitability of this material for roll-to-roll coating. Preliminary results on the applicability of AZO as electron injection layer in F8BT-based polymer light emitting diode are also presented. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Amorphous calcium carbonate particles form coral skeletons

    Science.gov (United States)

    Mass, Tali; Giuffre, Anthony J.; Sun, Chang-Yu; Stifler, Cayla A.; Frazier, Matthew J.; Neder, Maayan; Tamura, Nobumichi; Stan, Camelia V.; Marcus, Matthew A.; Gilbert, Pupa U. P. A.

    2017-09-01

    Do corals form their skeletons by precipitation from solution or by attachment of amorphous precursor particles as observed in other minerals and biominerals? The classical model assumes precipitation in contrast with observed “vital effects,” that is, deviations from elemental and isotopic compositions at thermodynamic equilibrium. Here, we show direct spectromicroscopy evidence in Stylophora pistillata corals that two amorphous precursors exist, one hydrated and one anhydrous amorphous calcium carbonate (ACC); that these are formed in the tissue as 400-nm particles; and that they attach to the surface of coral skeletons, remain amorphous for hours, and finally, crystallize into aragonite (CaCO3). We show in both coral and synthetic aragonite spherulites that crystal growth by attachment of ACC particles is more than 100 times faster than ion-by-ion growth from solution. Fast growth provides a distinct physiological advantage to corals in the rigors of the reef, a crowded and fiercely competitive ecosystem. Corals are affected by warming-induced bleaching and postmortem dissolution, but the finding here that ACC particles are formed inside tissue may make coral skeleton formation less susceptible to ocean acidification than previously assumed. If this is how other corals form their skeletons, perhaps this is how a few corals survived past CO2 increases, such as the Paleocene-Eocene Thermal Maximum that occurred 56 Mya.

  1. Anodic electrochemical treatment of amorphous alloys

    International Nuclear Information System (INIS)

    Isaev, N.I.; Yakovlev, V.B.; Osipov, Eh.K.; Isaev, A.V.; Trofimova, E.A.; Vasil'ev, V.Yu.

    1983-01-01

    The aim of the investigation is to reveal peculiarities of the process of anodic oxidation and properties of anode oxide films, formed on the surface of amorphous alloys. Amorphous alloys on the base of rectifying metals of Zr-Ni, Zr-Cu-Ni, Zr-Al-Ni, Zr-Cu-Sn, Zr-Al, Zr-Mo systems are studied. Electrolytes which do not dissolve or weakly dissolve oxide film, such as boric acid electrolyte (40-45 g/l H 3 BO 3 and 18 cm 3 /l of the 25% aqueous NH 4 OH solution) and 20% H 2 SO 4 solution, are used for oxidation. Results of investigations, carried out on amorphous alloys, contaning noticeable quantities of non-rectifying components - Cu, Ni, Sn, Fe, Mo etc - have shown that non-rectifying components harden a process of anodic oxidation and decrease the current efficiency. Amorphous alloys, containing only rectifying components are oxidated in anodic way, the regularities of film growth being similar to those obtained for crystalline materials

  2. Understanding the generation and maintenance of supersaturation during the dissolution of amorphous solid dispersions using modulated DSC and 1H NMR.

    Science.gov (United States)

    Baghel, Shrawan; Cathcart, Helen; O'Reilly, Niall J

    2018-01-30

    In this study, the dissolution behaviour of dipyridamole (DPM) and cinnarizine (CNZ) spray-dried amorphous solid dispersions (ASDs) using polyvinyl pyrrolidone (PVP) and polyacrylic acid (PAA) as a carrier matrix were evaluated and compared. The drug concentrations achieved from the dissolution of PVP and PAA solid dispersions were significantly greater than the equilibrium solubility of crystalline DPM and CNZ in phosphate buffer pH 6.8 (PBS 6.8). The maximum drug concentration achieved by dissolution of PVP and PAA solid dispersions did not exceed the theoretically calculated apparent solubility of amorphous DPM and CNZ. However, the degree of supersaturation of DPM and CNZ increased considerably as the polymer weight fraction within the solid dispersion increased. In addition, the supersaturation profile of DPM and CNZ were studied in the presence and absence of the polymers. PAA was found to maintain a higher level of supersaturation compared to PVP. The enhanced drug solution concentration following dissolution of ASDs can be attributed to the reduced crystal growth rates of DPM and CNZ at an equivalent supersaturation. We have also shown that, for drugs having high crystallization tendency and weak drug-polymer interaction, the feasible way to increase dissolution might be increase the polymer weight fraction in the ASD. Solution 1 H NMR spectra were used to understand dissolution mechanism and to identify drug-polymer interaction. The change in electron densities of proton attached to different groups in DPM and CNZ suggested drug-polymer interaction in solution. The relative intensities of peak shift and nature of interaction between drug and polymer in different systems are different. These different effects suggest that DPM and CNZ interacts in a different way with PVP and PAA in solution which goes some way towards explaining the different polymeric effect, particularly in terms of inhibition of drug recrystallization and dissolution of DPM and CNZ ASDs

  3. Research on the structure in solution of optically active synthetic polymers (propylene polysulphide, propylene polyoxide, tertio-butyl polysulphide); Recherche de la structure en solution de polymeres synthetiques, optiquement actifs (polysulfure de propylene, polyoxyde de propylene, polysulfure de tertiobutyle)

    Energy Technology Data Exchange (ETDEWEB)

    Sarrazin, Brigitte

    1971-03-15

    It was proposed to study the structure of sulphur-containing synthetic polymers, stereo-regular, optically active in solution and able to adopt a spiral conformation, with special reference to propylene polysulphide. Two methods were used, the first mathematical (conformational energy calculations) and the second physico-chemical, essentially spectroscopic. By conformational analysis it is possible to choose the most probable structures liable to be adopted by a given polymer in solution while the spectro-polarimetric study should, in principle, invalidate or confirm certain of these hypotheses. The conformational energy calculations showed that in fact there is no energy conformation low enough to be stable in solution. Strictly speaking however we can refer to a region of stability in which steric hindrance is low and many energy minima exist. These minima are indistinguishable both by their energy values and by their spatial localizations and are all enclosed in the region bounded by the barriers due to steric hindrance. This uncertainty does not arise from approximations made in the calculations, but from the multitude of stereochemical structure possible. Investigations into the variation of the optical rotary dispersion and the circular dichroism as a function of temperature indicated the existence of three or more equilibrium states in the dioxane. The spectra appear to be the summation of the optical activities of the numerous simultaneously possible conformations. It appears that polymers, such as propylene polysulphide or propylene polyoxide do not have stable structures in solution. These are molecules of great flexibility possessing a large number of degrees of freedom. These properties distinguish them from the natural polymers, carrying precise information, such as DNA which must consequently have stable conformations. (author) [French] On s'est propose d'etudier la structure de polymeres synthetiques soufres, stereoreguliers, optiquement actifs en

  4. Characterization of Amorphous and Co-Amorphous Simvastatin Formulations Prepared by Spray Drying

    DEFF Research Database (Denmark)

    Craye, Goedele; Löbmann, Korbinian; Grohganz, Holger

    2015-01-01

    In this study, spray drying from aqueous solutions, using the surface-active agent sodium lauryl sulfate (SLS) as a solubilizer, was explored as a production method for co-amorphous simvastatin-lysine (SVS-LYS) at 1:1 molar mixtures, which previously have been observed to form a co...

  5. Kinetics of polymer degradation in solution. 6. Laser flash photolysis and pulse radiolysis studies of polymethylvinylketone in solution using the light scattering detection method

    Energy Technology Data Exchange (ETDEWEB)

    Lindenau, D; Beavan, S W; Beck, G; Schnabel, W [Hahn-Meitner-Institut fuer Kernforschung Berlin G.m.b.H. (Germany, F.R.)

    1977-01-01

    Polymethylvinylketone (PMVK) was irradiated in solution with 2 ..mu..s pulses of 15 MeV electrons or with 15 ns flashes of 262 nm light. The change of the intensity of the light scattered by the solution (LSI) after the irradiation was measured. For the radiolysis experiments, a main chain scission process tausub(1/2) (decr) approximately 20 ..mu..s) and a subsequent crosslinking process (tausub(1/2) (incr) approximately 0.4 sec) could be discriminated. The LSI change pertaining to the main chain degradation was found to be due to disentanglement diffusion, whereas the LSI change pertaining to the crosslinking process could be correlated to a chemical reaction. The rate constant for combination of lateral macroradicals in acetone solution was estimated as 2 k/sub 2/ - (4.5 +- 1.5)10/sup 6/ M/sup -1/ sec/sup -1/. Stationary irradiation with /sup 60/Co-..gamma..-rays showed that PMVK is predominantly crosslinked to form a macrogel when irradiated in the solid state or in solution at concentrations greater than 100 g/l. At lower concentrations, microgel formation occurred. Photolysis of PMVK in solution yielded only main chain degradation. The LSI change was found to be due to disentanglement diffusion as during radiolysis. It was concluded that the same mechanism for main chain rupture is operative as in radiolysis. Stationary irradiations with uv light (lambda > 260 nm ) resulted in main chain degradation; no indication of crosslinking was obtained.

  6. Synthesis, characterization, and application of novel Zn(II)-ionic imprinted polymer for preconcentration of Zn(II) ions from aqueous solution

    Science.gov (United States)

    Wirawan, T.; Supriyanto, G.; Soegianto, A.

    2018-04-01

    Preparation of a new Zn2+ ion-imprinted polymer (Zn-IIP) is presented in this report. The Zn-IIP are prepared by precipitation polymerization using 8-hydroxyquinoline (8HQ) as a ligand, methacrylic acid (MAA) as functional monomer, and ethylene glycol dimethacrylate (EGDMA) as a cross-linker has been prepared. The benzoyl peroxide and ethanol/acetonitrile (2:1) mixture were used as initiator and porogen, respectively. Precipitation polymerization was carried out by heating in a water bath at 60°C for 8 hours. After polymerization, cavities in the polymer particles corresponding to the Zn2+ ions were created by leaching the polymer with 2 mol L-1 HNO3. The polymer was washed with aquabidest and dried in an oven at the temperature of 60°C for 24 hours. The Zn-IIP was characterized by Fourier Transform Infrared Spectrophotometry (FT-IR) and Scanning Electron Microscopy (SEM). The synthesized Zn-IIP was used as a new adsorbent for solid phase extraction (SPE) of Zn(II) prior to Flame Atomic Absorption Spectrometry (FAAS) determination. The experimental parameters for SPE, such as pH of the sample, loading rate, and elution volume, have been optimized. The effect of pH of the sample on the extraction of analyte was studied in batch mode. The effects of loading rate and elution volume on the extraction of analyte were studied in dynamic mode by loading of the sample through IIP-SPE cartridge containing 100 mg of the synthesized Zn-IIP. The imprinted polymer (Zn-IIP) have bands at 3433.06 cm-1 (O-H), 1508.23 cm-1 (C=N aromatics), 1284.5 cm-1 (C-N aromatics), 1056.9 cm-1 (C-O phenol), 1724.24 cm-1 (C=O), and 1639.38 cm-1 (conjugated C=O with C=C). The Scanning Electron Microscopy (SEM) images of IIP and IIP show that the IIP is seen to have more cavities than NIP. The optimum pH for quantitative Zn(II) retention was 5.5, and the elution was completed with 2 mL of 1.0 mol L-1 nitric acid. The optimum loading rate was 0.5 mL min-1. The recovery of Zn(II) from solution

  7. Mechanical response of melt-spun amorphous filaments

    International Nuclear Information System (INIS)

    Leal, A A; Reifler, F A; Hufenus, R; Mohanty, G; Michler, J

    2014-01-01

    High-speed melt spinning of a cyclo-olefin polymer (COP) and a copolyamide (CoPA) have been performed. Differential scanning calorimetry curves of the resulting monofilaments show that they remain in an amorphous state even after hot drawing. Wide angle x-ray diffraction patterns of undrawn and drawn COP filaments show that although the material remains in an amorphous state, a degree of orientation is induced in the polymer after drawing. The amorphous filaments show an enhanced bending recovery with respect to different semi-crystalline monofilaments commercially available. However, single fiber axial compressive testing indicates that the amorphous filaments exhibit a compressive modulus value which is 50% lower than what is observed for a reference semi-crystalline PET filament. Analysis of the compressive strains applied by the bending recovery test indicates that while the maximum applied strains remain well within the region of elastic deformation of the amorphous materials, the threshold between elastic and plastic deformation is reached for the semi-crystalline materials. (paper)

  8. Electrodriven selective transport of Cs+ using chlorinated cobalt dicarbollide in polymer inclusion membrane: a novel approach for cesium removal from simulated nuclear waste solution.

    Science.gov (United States)

    Chaudhury, Sanhita; Bhattacharyya, Arunasis; Goswami, Asok

    2014-11-04

    The work describes a novel and cleaner approach of electrodriven selective transport of Cs from simulated nuclear waste solutions through cellulose tri acetate (CTA)/poly vinyl chloride (PVC) based polymer inclusion membrane. The electrodriven cation transport together with the use of highly Cs+ selective hexachlorinated derivative of cobalt bis dicarbollide, allows to achieve selective separation of Cs+ from high concentration of Na+ and other fission products in nuclear waste solutions. The transport selectivity has been studied using radiotracer technique as well as atomic emission spectroscopic technique. Transport studies using CTA based membrane have been carried out from neutral solution as well as 0.4 M HNO3, while that with PVC based membrane has been carried out from 3 M HNO3. High decontamination factor for Cs+ over Na+ has been obtained in all the cases. Experiment with simulated high level waste solution shows selective transport of Cs+ from most of other fission products also. Significantly fast Cs+ transport rate along with high selectivity is an interesting feature observed in this membrane. The current efficiency for Cs+ transport has been found to be ∼100%. The promising results show the possibility of using this kind of electrodriven membrane transport methods for nuclear waste treatment.

  9. Organic-Inorganic Hybrid Polymers as Adsorbents for Removal of Heavy Metal Ions from Solutions: A Review

    Science.gov (United States)

    Samiey, Babak; Cheng, Chil-Hung; Wu, Jiangning

    2014-01-01

    Over the past decades, organic-inorganic hybrid polymers have been applied in different fields, including the adsorption of pollutants from wastewater and solid-state separations. In this review, firstly, these compounds are classified. These compounds are prepared by sol-gel method, self-assembly process (mesopores), assembling of nanobuilding blocks (e.g., layered or core-shell compounds) and as interpenetrating networks and hierarchically structures. Lastly, the adsorption characteristics of heavy metals of these materials, including different kinds of functional groups, selectivity of them for heavy metals, effect of pH and synthesis conditions on adsorption capacity, are studied. PMID:28788483

  10. Low-temperature, solution-processed aluminum-doped zinc oxide as electron transport layer for stable efficient polymer solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Qianqian [College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Bao, Xichang, E-mail: baoxc@qibebt.ac.cn [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Yu, Jianhua [College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Zhu, Dangqiang [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Zhang, Qian [College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Gu, Chuantao [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Dong, Hongzhou [College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Yang, Renqiang [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Dong, Lifeng, E-mail: DongLifeng@qust.edu.cn [College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Department of Physics, Hamline University, St. Paul, MN 55104 (United States)

    2016-04-30

    A simple low-temperature solution-processed zinc oxide (ZnO) and aluminum-doped ZnO (AZO) were synthesized and investigated as an electron transport layer (ETL) for inverted polymer solar cells. A solar cell with a blend of poly(4,8-bis-alkyloxy-benzo[1,2-b:4,5-b′] dithiophene-alt-alkylcarbonyl-thieno [3,4-b] thiophene) and (6,6)-phenyl-C71-butyric acid methyl ester as an active layer and AZO as ETL demonstrates a high power conversion efficiency (PCE) of 7.36% under the illumination of AM 1.5G, 100 mW/cm{sup 2}. Compared to the cells with ZnO ETL (PCE of 6.85%), the PCE is improved by 7.45% with the introduction of an AZO layer. The improved PCE is ascribed to the enhanced short circuit current density, which results from the electron transport property of the AZO layer. Moreover, AZO is a more stable interfacial layer than ZnO. The PCE of the solar cells with AZO as ETL retain 85% of their original value after storage for 120 days, superior to the 39% of cells with ZnO ETL. The results above indicate that a simple low-temperature solution-processed AZO film is an efficient and economical ETL for high-performance inverted polymer solar cells. Due to its environmental friendliness, good electrical properties, and simple preparation approach, AZO has the potential to be applied in high-performance, large-scale industrialization of solar cells and other electronic devices. - Highlights: • ZnO and AZO were synthesized by a simple low-temperature solution-processed method. • AZO films show high transmittance and conductivity. • The photovoltaic performance can be improved with AZO as ETL. • AZO-based devices demonstrate excellent stability, with 85% retained after 120 days.

  11. Monte Carlo simulations of confined polymer systems

    NARCIS (Netherlands)

    Vliet, Johannes Henricus van

    1991-01-01

    This thesis considers confined polymer systems. These systems are of considerable interest, e.g., thin polymer films, chromotography of polymer solutions, drag reduction, enhanced oil recovery, stabilization of colloidal dispersions, lubrication and biolubrication. The method used to study these

  12. 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.

  13. Fabrication and characterization of WO3/Ag/WO3 multilayer transparent anode with solution-processed WO3 for polymer light-emitting diodes.

    Science.gov (United States)

    Jeon, Kangmin; Youn, Hongseok; Kim, Seongbeom; Shin, Seongbeom; Yang, Minyang

    2012-05-15

    The dielectric/metal/dielectric multilayer is suitable for a transparent electrode because of its high-optical and high-electrical properties; however, it is fabricated by an expensive and inefficient multistep vacuum process. We present a WO3/Ag/WO3 (WAW) multilayer transparent anode with solution-processed WO3 for polymer light-emitting diodes (PLEDs). This WAW multilayer not only has high transmittance and low resistance but also can be easily and rapidly fabricated. We devised a novel method to deposit a thin WO3 layer by a solution process in an air environment. A tungstic acid solution was prepared from an aqueous solution of Na2WO4 and then converted to WO3 nanoparticles (NPs) by a thermal treatment. Thin WO3 NP layers form WAW multilayer with a thermal-evaporated Ag layer, and they improve the transmittance of the WAW multilayer because of its high transmittance and refractive index. Moreover, the surface of the WO3 layer is homogeneous and flat with low roughness because of the WO3 NP generation from the tungstic acid solution without aggregation. We performed optical simulation and experiments, and the optimized WAW multilayer had a high transmittance of 85% with a sheet resistance of 4 Ω/sq. Finally, PLEDs based on the WAW multilayer anode achieved a maximum luminance of 35,550 cd/m2 at 8 V, and this result implies that the solution-processed WAW multilayer is appropriate for use as a transparent anode in PLEDs.

  14. [Verification of a decrease in the rigidity of the phage lambda DNA polymeric chain in low ionic strength aqueous solutions by testing the polymer-polymer interlink interactions].

    Science.gov (United States)

    Arutiunian, A V; Ivanova, M A; Kurliand, D I; Kapshin, Iu S; Landa, S B; Poshekhonov, S T; Drobchenko, E A; Shevelev, I V

    2011-01-01

    Changes in the rigidity of the polymetric chain of phage lambda double-strand DNA have been studied by laser correlation spectroscopy. It was shown that, as the ionic strength increases, the effect of the screening of the hydrodynamic interaction of the links of the polymeric chain specific for polymeric coils arises in a DNA solution. It is assumed that the screening occurs when the threshold of the overlapping of DNA coils is achieved. The overlapping of coils is the result of a previously observed significant rise of DNA coil size from abnormally small DNA coils in low ionic strength buffers (about 10(-2) M Na+ or less) to maximum possible large coils in the 5SSC and 5SSC-like buffers. Further analysis of the far interlink interactions in linear lambda phage DNA coils in similar buffers at pH 7 and 4 confirms the earlier proposal about the role of H+ ions in the appearance of abnormally small DNA coils. The abnormal decrease in the DNA coil size in low ionic strength buffers is not a specific feature of lambda phage DNA only.

  15. A novel method for determining the solubility of small molecules in aqueous media and polymer solvent systems using solution calorimetry.

    Science.gov (United States)

    Fadda, Hala M; Chen, Xin; Aburub, Aktham; Mishra, Dinesh; Pinal, Rodolfo

    2014-07-01

    To explore the application of solution calorimetry for measuring drug solubility in experimentally challenging situations while providing additional information on the physical properties of the solute material. A semi-adiabatic solution calorimeter was used to measure the heat of dissolution of prednisolone and chlorpropamide in aqueous solvents and of griseofulvin and ritonavir in viscous solutions containing polyvinylpyrrolidone and N-ethylpyrrolidone. Dissolution end point was clearly ascertained when heat generation stopped. The heat of solution was a linear function of dissolved mass for all drugs (solution of 9.8 ± 0.8, 28.8 ± 0.6, 45.7 ± 1.6 and 159.8 ± 20.1 J/g were obtained for griseofulvin, ritonavir, prednisolone and chlorpropamide, respectively. Saturation was identifiable by a plateau in the heat signal and the crossing of the two linear segments corresponds to the solubility limit. The solubilities of prednisolone and chlopropamide in water by the calorimetric method were 0.23 and 0.158 mg/mL, respectively, in agreement with the shake-flask/HPLC-UV determined values of 0.212 ± 0.013 and 0.169 ± 0.015 mg/mL, respectively. For the higher solubility and high viscosity systems of griseofulvin and ritonavir in NEP/PVP mixtures, respectively, solubility values of 65 and 594 mg/g, respectively, were obtained. Solution calorimetry offers a reliable method for measuring drug solubility in organic and aqueous solvents. The approach is complementary to the traditional shake-flask method, providing information on the solid properties of the solute. For highly viscous solutions, the calorimetric approach is advantageous.

  16. Electrochemical synthesis of novel polymer based on (4-(2,3-dihydrothieno[3,4-6][1,4][dioxin-5-yl) aniline) in aqueous solution: Characterization and application

    Energy Technology Data Exchange (ETDEWEB)

    Shahhosseini, Leyla [Chemistry Department, Kerman Branch, Islamic Azad University, Kerman (Iran, Islamic Republic of); Nateghi, Mohammad Reza, E-mail: mnateghi@iauyazd.ac.ir [Chemistry Department, Yazd Branch, Islamic Azad University, Yazd (Iran, Islamic Republic of); Kazemipour, Maryam [Chemistry Department, Kerman Branch, Islamic Azad University, Kerman (Iran, Islamic Republic of); Borhani Zarandi, Mahmoud [Department of Physics, Yazd University, P.O. Box 97175/615, Yazd (Iran, Islamic Republic of)

    2016-07-01

    4-(2,3-dihydrothieno[3,4-6][1,4][dioxin-5-yl) aniline, an interesting novel monomer was successfully synthesized in which α-carbon on ethylenedioxythiophene was linked to aniline at para position. The structure of the monomer was approved by infrared (IR), gas chromatography-mass spectrometry (GC-MS) and {sup 1}H nuclear magnetic resonance ({sup 1}H NMR) spectroscopies. Poly (4-(2,3-dihydrothieno[3,4-6][1,4][dioxin-5-yl) aniline) and its composite with graphene were electrochemically synthesized in aqueous solution by cyclic potential sweep method. The Polymer was characterized by IR and UV–vis spectroscopies, scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy techniques. Electrochemical synthesis conditions were optimized to prepare high conducting and porous polymer so it can be efficiently used as a counter electrode in fabrication of dye sensitized solar cells. Photovoltaic experiments revealed that energy conversion efficiency of the solar cell fabricated using polymer composite (7.52%) is 21% greater than that prepared by Pt counter electrode (6.19%). - Highlights: • A Novel monomer comprising aniline and EDOT was synthesized by a simple process. • Poly (ANI-EDOT) was synthesized and characterized by cyclic potential sweep method. • The copolymer changes from yellow at −0.9 V to dark green color at +0.9 V reversibly. • Poly (ANI-EDOT)/graphene is porous with electrocatalytic effect on I{sub 3}{sup −} reduction.

  17. Roll-to-Roll Printed Silver Nanowire Semitransparent Electrodes for Fully Ambient Solution-Processed Tandem Polymer Solar Cells

    DEFF Research Database (Denmark)

    Angmo, Dechan; Andersen, Thomas Rieks; Bentzen, Janet Jonna

    2015-01-01

    Silver nanowires (AgNWs) and zinc oxide (ZnO) are deposited on flexible substrates using fast roll-to-roll (R2R) processing. The AgNW film on polyethylene terephthalate (PET) shows >80% uniform optical transmission in the range of 550-900 nm. This electrode is compared to the previously reported...... spectrum reaching up to 40% increased transmission at 750 nm in comparison to Flextrode. The functionality of AgNW electrodes is demonstrated in single and tandem polymer solar cells and compared with parallel devices on traditional Flextrode. All layers, apart from the semitransparent electrodes which...... are large-scale R2R produced, are fabricated in ambient conditions on a laboratory roll-coater using printing and coating methods which are directly transferrable to large-scale R2R processing upon availability of materials. In a single cell structure, Flextrode is preferable with active layers based...

  18. Removal and recovery of molybdenum from aqueous solutions by adsorption onto Surfactant-Modified coir pith, a lignocellulosic polymer

    Energy Technology Data Exchange (ETDEWEB)

    Namasivayam, Chinnaiya [Environmental Chemistry Division, Department of Environmental Sciences, Bharathiar University, Coimbatore (India); Sureshkumar, Molagoundanpalayam Venkatachalam [Department of Chemistry, PARK College of Engineering and Technology, Coimbatore (India)

    2009-01-15

    Coconut coir pith, a lignocellulosic polymer, is an unwanted by-product of the coir fiber industry. The pith was used as a biosorbent for the removal of Molybdenum(VI) after modification with a cationic surfactant, hexadecyltrimethylammonium bromide. The optimum pH for maximum adsorption of Mo(VI) was found to be 3.0. Langmuir, Freundlich and Dubinin Radushkevich isotherms were used to model the adsorption equilibrium data and the system was seen to follow all three isotherms. The Langmuir adsorption capacity of the biosorbent was found to be 57.5 mg g{sup -1}. Kinetic studies showed that the adsorption generally obeyed a second-order kinetic model. Desorption studies showed that the recovery of Mo(VI) from the spent adsorbent was feasible. The effect of foreign anions on the adsorption of Mo(VI) was also examined. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  19. Molar mass fractionation in aqueous two-phase polymer solutions of dextran and poly(ethylene glycol).

    Science.gov (United States)

    Zhao, Ziliang; Li, Qi; Ji, Xiangling; Dimova, Rumiana; Lipowsky, Reinhard; Liu, Yonggang

    2016-06-24

    Dextran and poly(ethylene glycol) (PEG) in phase separated aqueous two-phase systems (ATPSs) of these two polymers, with a broad molar mass distribution for dextran and a narrow molar mass distribution for PEG, were separated and quantified by gel permeation chromatography (GPC). Tie lines constructed by GPC method are in excellent agreement with those established by the previously reported approach based on density measurements of the phases. The fractionation of dextran during phase separation of ATPS leads to the redistribution of dextran of different chain lengths between the two phases. The degree of fractionation for dextran decays exponentially as a function of chain length. The average separation parameters, for both dextran and PEG, show a crossover from mean field behavior to Ising model behavior, as the critical point is approached. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Polymer solar cells with efficiency >10% enabled via a facile solution-processed Al-doped ZnO electron transporting layer

    KAUST Repository

    Jagadamma, Lethy Krishnan

    2015-10-05

    The present work details a facile and low-temperature (125C) solution-processed Al-doped ZnO (AZO) buffer layer functioning very effectively as electron accepting/hole blocking layer for a wide range of polymer:fullerene bulk heterojunction systems, and yielding power conversion efficiency in excess of 10% (8%) on glass (plastic) substrates. We show that ammonia addition to the aqueous AZO nanoparticle solution is a critically important step toward producing compact and smooth thin films which partially retain the aluminum doping and crystalline order of the starting AZO nanocrystals. The ammonia treatment appears to reduce the native defects via nitrogen incorporation, making the AZO film a very good electron transporter and energetically matched with the fullerene acceptor. Importantly, highly efficient solar cells are achieved without the need for additional surface chemical passivation or modification, which has become an increasingly common route to improving the performance of evaporated or solution-processed ZnO ETLs in solar cells.

  1. Shelf life stability comparison in air for solution processed pristine PDPP3T polymer and doped spiro-OMeTAD as hole transport layer for perovskite solar cell

    Directory of Open Access Journals (Sweden)

    Ashish Dubey

    2016-06-01

    Full Text Available This data in brief includes forward and reverse scanned current density–voltage (J–V characteristics of perovskite solar cells with PDPP3T and spiro-OMeTAD as HTL, stability testing conditions of perovskite solar cell shelf life in air for both PDPP3T and spiro-OMeTAD as HTL as per the description in Ref. [1], and individual J–V performance parameters acquired with increasing time exposed in ambient air are shown for both type of devices using PDPP3T and spiro-OMeTAD as HTL. The data collected in this study compares the device stability with time for both PDPP3T and spiro-OMeTAD based perovskite solar cells and is directly related to our research article “solution processed pristine PDPP3T polymer as hole transport layer for efficient perovskite solar cells with slower degradation” [2].

  2. Corrosion inhibition of aluminum with a series of aniline monomeric surfactants and their analog polymers in 0.5 M HCl solution

    Directory of Open Access Journals (Sweden)

    M.M. El-Deeb

    2015-07-01

    Full Text Available The inhibition effect of 3-(12-sodiumsulfonate dodecyloxy aniline monomeric surfactant (MC12 and its analog polymer Poly 3-(dodecyloxy sulfonic acid aniline (PC12 on the corrosion of aluminum in 0.5 M HCl solution was investigated using weight loss and potentiodynamic polarization techniques. The presence of these two compounds in 0.5 M HCl inhibits the corrosion of aluminum without modifying the mechanism of corrosion process. It was found that these inhibitors act as mixed-type inhibitors with anodic predominance as well as the inhibition efficiency increases with increasing inhibitor concentration, but decreases with raising temperature. Langmuir and Frumkin adsorption isotherms fit well with the experimental data. Thermodynamic functions for both dissolution and adsorption processes were determined. The obtained results from weight loss and potentiodynamic polarization techniques are in good agreement with contact angle measurements.

  3. Amorphous silicon radiation detectors

    Science.gov (United States)

    Street, Robert A.; Perez-Mendez, Victor; Kaplan, Selig N.

    1992-01-01

    Hydrogenated amorphous silicon radiation detector devices having enhanced signal are disclosed. Specifically provided are transversely oriented electrode layers and layered detector configurations of amorphous silicon, the structure of which allow high electric fields upon application of a bias thereby beneficially resulting in a reduction in noise from contact injection and an increase in signal including avalanche multiplication and gain of the signal produced by incoming high energy radiation. These enhanced radiation sensitive devices can be used as measuring and detection means for visible light, low energy photons and high energy ionizing particles such as electrons, x-rays, alpha particles, beta particles and gamma radiation. Particular utility of the device is disclosed for precision powder crystallography and biological identification.

  4. Synthesis and characterization of an electrolyte system based on a biodegradable polymer

    Directory of Open Access Journals (Sweden)

    K. Sownthari

    2013-06-01

    Full Text Available A polymer electrolyte system has been developed using a biodegradable polymer namely poly-ε-caprolactone (PCL in combination with zinc triflate [Zn(CF3SO32] in different weight percentages and characterized during this investigation. Free-standing thin films of varying compositions were prepared by solution casting technique. The successful doping of the polymer has been confirmed by means of Fourier transform infrared spectroscopy (FTIR by analyzing the carbonyl (C=O stretching region of the polymer. The maximum ionic conductivity obtained at room temperature (25°C was found to be 8.8x10–6 S/cm in the case of PCL complexed with 25 wt% Zn(CF3SO32 which is five orders of magnitude higher than that of the pure polymer host material. The increase in amorphous phase with an increase in salt concentration of the prepared polymer electrolyte has also been confirmed from the concordant results obtained from X-ray diffraction (XRD, differential scanning calorimetry (DSC and scanning electron microscopic (SEM analyses. Furthermore, the electrochemical stability window of the prepared polymer electrolyte was found to be 3.7 V. An electrochemical cell has been fabricated based on Zn/MnO2 electrode couple as an application area and its discharge characteristics were evaluated.

  5. Formation and structure of V-Zr amorphous alloy thin films

    KAUST Repository

    King, Daniel J M; Middleburgh, Simon C.; Liu, A. C Y; Tahini, Hassan Ali; Lumpkin, Gregory R.; Cortie, Michael B.

    2015-01-01

    . Atomic-scale modelling was used to investigate the enthalpies of formation of the various competing structures. The calculations confirmed that an amorphous solid solution would be significantly more stable than a random body-centred solid solution

  6. All solution roll-to-roll processed polymer solar cells free from indium-tin-oxide and vacuum coating steps

    DEFF Research Database (Denmark)

    Krebs, Frederik C

    2009-01-01

    of a bottom electrode comprising silver nanoparticles on a 130 micron thick polyethyleneternaphthalate (PEN) substrate. Subsequently an electron transporting layer of zinc oxide nanoparticles was applied from solution followed by an active layer of P3HT-PCBM and a hole transporting layer of PEDOT......, 3 and 8 stripes. All five layers in the device were processed from solution in air and no vacuum steps were employed. An additional advantage is that the use of indium-tin-oxide (ITO) is avoided in this process. The devices were tested under simulated sunlight (1000 W m−2, AM1.5G) and gave a typical...

  7. Solution-processed high-LUMO-level polymers in n-type organic field-effect transistors: a comparative study as a semiconducting layer, dielectric layer, or charge injection layer

    International Nuclear Information System (INIS)

    Liu, Chuan; Xu, Yong; Liu, Xuying; Minari, Takeo; Sirringhaus, Henning; Noh, Yong-Young

    2015-01-01

    In solution-processed organic field-effect transistors (OFETs), the polymers with high level of lowest unoccupied molecular orbitals (LUMOs, > −3.5 eV) are especially susceptible to electron-trapping that causes low electron mobility and strong instability in successive operation. However, the role of high-LUMO-level polymers could be different depending on their locations relative to the semiconductor/insulator interface, or could even possibly benefit the device in some cases. We constructed unconventional polymer heterojunction n-type OFETs to control the location of the same polymer with a high LUMO level, to be in, under, or above the accumulation channel. We found that although the devices with the polymer in the channel suffer from dramatic instability, the same polymer causes much less instability when it acts as a dielectric modification layer or charge injection layer. Especially, it may even improve the device performance in the latter case. This result helps to improve our understanding of the electron-trapping and explore the value of these polymers in OFETs. (invited article)

  8. Thermotropic phase transition in aqueous polymer solutions and gels as studied by .sup.1./sup.H NMR methods

    Czech Academy of Sciences Publication Activity Database

    Spěváček, Jiří; Hanyková, L.; Starovoytova, L.; Ilavský, Michal

    2002-01-01

    Roč. 2, č. 3 (2002), s. 36-43 ISSN 1335-8243 R&D Projects: GA AV ČR IAA4050209 Grant - others:GA UK(XC) 164/2001B Institutional research plan: CEZ:AV0Z4050913 Keywords : thermotropic phase transition * collapse * D 2 O solutions and gels Subject RIV: CD - Macromolecular Chemistry

  9. Methods of amorphization and investigation of the amorphous state

    OpenAIRE

    EINFALT, TOMAŽ; PLANINŠEK, ODON; HROVAT, KLEMEN

    2013-01-01

    The amorphous form of pharmaceutical materials represents the most energetic solid state of a material. It provides advantages in terms of dissolution rate and bioavailability. This review presents the methods of solid-state amorphization described in literature (supercooling of liquids, milling, lyophilization, spray drying, dehydration of crystalline hydrates), with the emphasis on milling. Furthermore, we describe how amorphous state of pharmaceuticals differ depending on method of prepara...

  10. The Stabilization of Amorphous Zopiclone in an Amorphous Solid Dispersion.

    Science.gov (United States)

    Milne, Marnus; Liebenberg, Wilna; Aucamp, Marique

    2015-10-01

    Zopiclone is a poorly soluble psychotherapeutic agent. The aim of this study was to prepare and characterize an amorphous form of zopiclone as well as the characterization and performance of a stable amorphous solid dispersion. The amorphous form was prepared by the well-known method of quench-cooling of the melt. The solid dispersion was prepared by a solvent evaporation method of zopiclone, polyvinylpyrrolidone-25 (PVP-25), and methanol, followed by freeze-drying. The physico-chemical properties and stability of amorphous zopiclone and the solid dispersion was studied using differential scanning calorimetry (DSC), infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), hot-stage microscopy (HSM), X-ray diffractometry (XRD), solubility, and dissolution studies. The zopiclone amorphous solid-state form was determined to be a fragile glass; it was concluded that the stability of the amorphous form is influenced by both temperature and water. Exposure of amorphous zopiclone to moisture results in rapid transformation of the amorphous form to the crystalline dihydrated form. In comparison, the amorphous solid dispersion proved to be more stable with increased aqueous solubility.

  11. Low-cost fused taper polymer optical fiber (LFT-POF) splitters for environmental and home-networking solution

    Science.gov (United States)

    Supian, L. S.; Ab-Rahman, Mohammad Syuhaimi; Harun, Mohd Hazwan; Gunab, Hadi; Sulaiman, Malik; Naim, Nani Fadzlina

    2017-08-01

    In visible optical communication over the multimode PMMA fibers, the overall cost of optical network can be reduced by deploying economical splitters for distributing the optical data signals from a point to multipoint in transmission network. The low-cost splitters shall have two main characteristics; good uniformity and high power efficiency. The most cost-effective and environmental friendly optical splitter having those characteristics have been developed. The device material is 100% purely based on the multimode step-index PMMA Polymer Optical Fiber (POF). The region which all fibers merged as single fiber is called as fused-taper POF. This ensures that all fibers are melted and fused properly. The results for uniformity and power efficiency of all splitters have been revealed by injecting red LED transmitter with 650 nm wavelength into input port while each end of output fibers measured by optical power meter. Final analysis shows our fused-taper splitter has low excess loss 0.53 dB and each of the output port has low insertion loss, which the average value is below 7 dB. In addition, the splitter has good uniformity that is 32:37:31% in which it is suitably used for demultiplexer fabrication.

  12. Final Closeout report for grant FG36-08GO18018, titled: Functional Multi-Layer Solution Processable Polymer Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Adam J. Moule

    2012-05-01

    The original objectives were: (1) Develop a method to deposit multiple conjugated polymer film layers and avoid the problem of dissolution from mutually solubility; (2) Use this deposition method to develop multi-layer polymer based solar cells with layers that are function specific; (3) characterize these layers and devices; (4) develop electrical and optical models that describe and predict the properties of the multi-layers; and (5) Ultimate efficiency goals are {approx}6.75% with J{sub sc} = 12 mA/cm{sup 2}, FF = 0.75, and V{sub oc} = 0.75. The question of whether photovoltaic (PV) cells will ever be able to replace fossil fuels as the main provider of electrical power is not just a question of device efficiency; it is a question of how much power can be provided for what price. It has been well documented that PV devices at 10% power efficiency can provide for all of the world's power needs without covering too much of the earth's surface. Assuming desert like cloud coverage, an area equivalent to the land area of Texas would have to be covered. However, it has also been shown that using the current state-of-the-art silicon devices, the price-per-Watt will never be low enough to be economically feasible for large-scale development. Solution-processable PV devices based on polymers are a very attractive alternative to traditional Silicon PV because this technology is much lower in materials cost and in environmentally toxic waste production. Solution-based polymers can be rapidly deposited using printing technologies and are compatible with light-weight flexible substrates that can increase the range of available PV applications. In the past ten years, the efficiency of polymer based PV devices has increased from {approx}1% to over 10%. The highest efficiency organic solar cells are based upon a single layer than consists of a mixture of donor and acceptor moieties. This one layer has multiple optical and electrical functions, so the design of a

  13. Pre-physical treatment: an important procedure to improve spectral resolution in polymers microstructure studies using 13C solution NMR

    International Nuclear Information System (INIS)

    Pedroza, Oscar J.O.; Tavares, Maria I.B.

    2004-01-01

    Changes in physical properties of polymeric materials can be evaluated from their microstructures, which can be investigated using solution carbon-13 nuclear magnetic resonance (NMR). In this type of study spectral resolution is very important, which obviously depend on the sample and solvent. A pre physical treatment allows for an improvement in the spectral resolution. Consequently, more information on chain linking can be obtained, thus facilitating the determination of the stereo sequences. (author)

  14. Ion implantation and amorphous metals

    International Nuclear Information System (INIS)

    Hohmuth, K.; Rauschenbach, B.

    1981-01-01

    This review deals with ion implantation of metals in the high concentration range for preparing amorphous layers (>= 10 at%, implantation doses > 10 16 ions/cm 2 ). Different models are described concerning formation of amorphous phases of metals by ion implantation and experimental results are given. The study of amorphous phases has been carried out by the aid of Rutherford backscattering combined with the channeling technique and using transmission electron microscopy. The structure of amorphous metals prepared by ion implantation has been discussed. It was concluded that amorphous metal-metalloid compounds can be described by a dense-random-packing structure with a great portion of metal atoms. Ion implantation has been compared with other techniques for preparing amorphous metals and the adventages have been outlined

  15. Preparation, characterization and application of superparamagnetic iron oxide nanoparticles modified with natural polymers for removal of {sup 60}Co-radionuclides from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Sharaf El-Deen, Gehan E. [Atomic Energy Authority, Cairo (Egypt). Radioactive Waste Management Dept.; Imam, Neama G. [Atomic Energy Authority, Cairo (Egypt). Experimental Physics Dept.; Elettra, Sincrotrone, Trieste (Italy); Ayoub, Refaat R. [Atomic Energy Authority, Cairo (Egypt). Nuclear Chemistry Dept.

    2017-04-01

    Superparamagnetic iron oxide nanoparticles (IO-MNPs) coated with natural polymers, starch (IO-S MNPs) and dextrin (IO-D MNPs), were synthesized by modified co-precipitation method. IO and hybrid-IO-MNPs were characterized by XRD, SEM, HRTEM, FT-IR spectroscopy, vibrating sample magnetometer (VSM) and zeta potential (ZP). IO-S MNPs and IO-D MNPs have IO core-shell structure with core of 10.8 nm and 13.8 nm and shell of 7.5 nm and 5.9 nm, respectively. The efficiency of the hybrid IO-MNPs for sorption of {sup 60}Co(II)-radionuclides from aqueous solution was investigated under varying experimental conditions. Kinetic data were described well by pseudo-second-order mode, sorption isotherms were fitted quite with Freundlich model with maximum adsorption capacity 36.89 (mmol.g{sup -1})/(L.mmol{sup -1}){sup n} for IO-S MNPs and 24.9 (mmol.g{sup -1})/(L.mmol{sup -1}){sup n} for IO-D MNPs. Sorption of {sup 60}Co-radionuclides by IO-S MNPs was suppressed with salinity and most of the adsorbed {sup 60}Co onto IO-S MNPs could be remove with 0.1 M HCl solution. IO-S MNPs exhibits superparamagnetic properties, easier separation according to higher saturation magnetization (47 emu/g) and better adsorption for {sup 60}CO-radionuclides than IO-D MNPs.

  16. Sm-doped CeO{sub 2} single buffer layer for YBCO coated conductors by polymer assisted chemical solution deposition (PACSD) method

    Energy Technology Data Exchange (ETDEWEB)

    Li, G.; Pu, M.H.; Sun, R.P.; Wang, W.T.; Wu, W.; Zhang, X.; Yang, Y. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu 610031 (China); Cheng, C.H. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu 610031 (China); School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW (Australia); Zhao, Y. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu 610031 (China); School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW (Australia)], E-mail: yzhao@home.swjtu.edu.cn

    2008-10-20

    An over 150 nm thick Sm{sub 0.2}Ce{sub 0.8}O{sub 1.9-x} (SCO) single buffer layer has been deposited on bi-axially textured NiW (2 0 0) alloy substrate. Highly in-plane and out-of-plane oriented, dense, smooth and crack free SCO single layer has been obtained via a polymer-assisted chemical solution deposition (PACSD) approach. YBCO thin film has been deposited equally via a PACSD route on the SCO-buffered NiW, the as grown YBCO yielding a sharp transition at T{sub c0} = 87 K as well as J{sub c}(0 T, 77 K) {approx} 1 MA/cm{sup 2}. These results indicates that RE (lanthanides other than Ce) doping may be an effective approach to improve the critical thickness of solution derived CeO{sub 2} film, which renders it a promising candidate as single buffer layer for YBCO coated conductors.

  17. Origins of amorphous interstellar grains

    International Nuclear Information System (INIS)

    Hasegawa, H.

    1984-01-01

    The existence of amorphous interstellar grains has been suggested from infrared observations. Some carbon stars show the far infrared emission with a lambda -1 wavelength dependence. Far infrared emission supposed to be due to silicate grains often show the lambda -1 wavelength dependence. Mid infrared spectra around 10 μm have broad structure. These may be due to the amorphous silicate grains. The condition that the condensed grains from the cosmic gas are amorphous is discussed. (author)

  18. Amorphous silicon based particle detectors

    OpenAIRE

    Wyrsch, N.; Franco, A.; Riesen, Y.; Despeisse, M.; Dunand, S.; Powolny, F.; Jarron, P.; Ballif, C.

    2012-01-01

    Radiation hard monolithic particle sensors can be fabricated by a vertical integration of amorphous silicon particle sensors on top of CMOS readout chip. Two types of such particle sensors are presented here using either thick diodes or microchannel plates. The first type based on amorphous silicon diodes exhibits high spatial resolution due to the short lateral carrier collection. Combination of an amorphous silicon thick diode with microstrip detector geometries permits to achieve micromete...

  19. Yield stress distribution in injection-moulded glassy polymers

    NARCIS (Netherlands)

    Verbeeten, W.M.H.; Kanters, M.J.W.; Engels, T.A.P.; Govaert, L.E.

    2015-01-01

    A methodology for structural analysis simulations is presented that incorporates the distribution of mechanical propertiesalong the geometrical dimensions of injection-moulded amorphous polymer products. It is based on a previously developedmodelling approach, where the thermomechanical history

  20. Thermal analysis studies of doping effects on the conformational motions of polymer chains in solid solutions with lasing molecules

    Science.gov (United States)

    Kalogeras, Ioannis M.; Pallikari, Fotini; Vassilikou-Dova, Aglaia; Neagu, Eugen R.

    2007-05-01

    The advancement of the solid-state dye laser performance largely depends on the systematic study of the dye-matrix interactions at the nanoscopic scale. The current work deals with blends of a comparatively inert dye host, poly(methyl methacrylate) (PMMA), with nonionic/apolar (substituted perylenes) and ionic/polar (rhodamine 6G, pyrromethene 567) dyes at ≈10-4 mol L-1 loading. Differential scanning calorimetry (DSC) and thermally stimulated currents (TSC) were used to explore the relative strength of inter- and intramolecular guest-host interactions by monitoring blending-induced modifications of the high-temperature signals: the segmental relaxation, the space-charge relaxation, and the liquid-liquid transition. Both techniques revealed the antiplasticizing role of the oligomeric organics on the relaxation dynamics of polymer segments, evidenced by clear glass-transition temperature upshifts. It becomes apparent that this effect is independent of the size, polarity, and ionicity of the dopant, signifying a common mechanism underway. It is suggested that, at least for the dyes under investigation, the chromophores simply fill the voids within the matrix, imposing strong steric hindrances on the rearrangement of the long-range structure. A comparison between the present results and earlier low-temperature dielectric data reveals that the large-scale relaxation dynamics show stronger perturbations due to blending, in comparison to the localized rotational motion of the pendant groups. DSC provided estimates for the unconverted monomer percentages in the solid blends. These were also determined more accurately by nuclear magnetic resonance (NMR), which additionally confirmed that the tacticity of the chains is not affected by the presence of the dye.