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Sample records for linked polymer solution

  1. The missing link between the extensional dynamics of polymer melts and solutions

    DEFF Research Database (Denmark)

    Rasmussen, Henrik K.; Huang, Qian

    2014-01-01

    Based on extensional viscosities measured on narrow molecular weight distributed (NMMD) polystyrenes and polystyrene oligomer dilutions thereof, we discuss the relation between the flow physics of polymer solutions and melts. A polymer solution is here characterized as a dilution where the diluen...

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

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Hejun [Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan 250100 (China); Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, China West Normal University, Nanchong 637000 (China); Kan, Taotao [CNOOC Energy Technology and Services-oilfield Technology Services Co., Tanggu, Tianjin 300452 (China); Zhao, Siyuan; Qian, Yixia; Cheng, Xiyuan; Wu, Wenli [School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Wang, Xiaodong [Shandong Provincial Analysis and Test Center, Jinan 250100 (China); Zheng, Liqiang, E-mail: lqzheng@sdu.edu.cn [Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan 250100 (China)

    2013-10-15

    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.

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

    OpenAIRE

    Mhd Radzi Bin Abas; Sharifah Mohamad; Yuk Ping Chin

    2010-01-01

    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 ...

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

    Science.gov (United States)

    Chin, Yuk Ping; Mohamad, Sharifah; Abas, Mhd Radzi Bin

    2010-01-01

    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. PMID:20957106

  5. 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.

  6. Removal of parabens from aqueous solution using β-cyclodextrin cross-linked polymer.

    Science.gov (United States)

    Chin, Yuk Ping; Mohamad, Sharifah; Abas, Mhd Radzi Bin

    2010-09-20

    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.

  7. Deformation of Linked Polymer Coils

    Institute of Scientific and Technical Information of China (English)

    董朝霞; 李明远; 吴肇亮; 林梅钦

    2003-01-01

    Linked polymer solution (LPS) is defined as the solution of linked polymer coils (LPCs) dispersed in water, composed of low concentration partially hydrolyzed polyacrylamide (HPAM) and aluminum citrate (crosslinker). In the work, the conformational changes of LPCs under different conditions were investigated by the methods of membrane filtering under low pressure, dynamic light scattering and core flooding experiments. The results showed that in some conditions the LPCs could be compressed mechanically to 1/158.5 of their original volume because of relatively lower HPAM cross-linking. The hydration property of LPCs was similar to that of normal polymer coils. The deformation of LPCs was more restricted than that of ordinary polymer coils under the flow shear stress or the shift of hydration equilibrium caused in the variation of the electrolyte concentration which is responsible for the effective plugging in the throats of porous media when LPCs are used for deep diverting.

  8. 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.

  9. Functionalized polymers for binding to solutes in aqueous solutions

    Science.gov (United States)

    Smith, Barbara F.; Robison, Thomas W.

    2006-11-21

    A functionalized polymer for binding a dissolved molecule in an aqueous solution is presented. The polymer has a backbone polymer to which one or more functional groups are covalently linked. The backbone polymer can be such polymers as polyethylenimine, polyvinylamine, polyallylamine, and polypropylamine. These polymers are generally water-soluble, but can be insoluble when cross-linked. The functional group can be for example diol derivatives, polyol derivatives, thiol and dithiol derivatives, guest-host groups, affinity groups, beta-diphosphonic acids, and beta-diamides

  10. Solution Processing - Rodlike Polymers

    Science.gov (United States)

    1979-08-01

    side it necessary and identify by block number) Para-ordered Polymers High Modulus Fibers and Films Polybenzobisoxazoles Polybenzobisthiazoles 20...considerations important in solution processing are considered, with special emphasis on the dry-jet wet spinning process used to form fibers . Pertinent...Company, Summit, N.J. iii TABLE OF CONTENTS 1. INTRODUCTION ................ .......................... .. 1 2. REMARKS ON DRY-JET WET SPUN FIBER

  11. Soft Confinement for Polymer Solutions

    CERN Document Server

    Oya, Yutaka

    2014-01-01

    As a model of soft confinement for polymers, we investigated equilibrium shapes of a flexible vesicle that contains a phase-separating polymer solution. To simulate such a system, we combined the phase field theory (PFT) for the vesicle and the self-consistent field theory (SCFT) for the polymer solution. We observed a transition from a symmetric prolate shape of the vesicle to an asymmetric pear shape induced by the domain structure of the enclosed polymer solution. Moreover, when a non-zero spontaneous curvature of the vesicle is introduced, a re-entrant transition between the prolate and the dumbbell shapes of the vesicle is observed. This re-entrant transition is explained by considering the competition between the loss of conformational entropy and that of translational entropy of polymer chains due to the confinement by the deformable vesicle. This finding is in accordance with the recent experimental result reported by Terasawa, et al.

  12. Turbulence in dilute polymer solutions

    Science.gov (United States)

    Liberzon, A.; Guala, M.; Lüthi, B.; Kinzelbach, W.; Tsinober, A.

    2005-03-01

    The work reported below is a comparative study of the properties of turbulence with weak mean flow in a Newtonian fluid and in a dilute polymer solution with an emphasis on the small scale phenomena. The main tool used is a three-dimensional particle tracking system allowing to measure and follow in a Lagrangian manner the field of velocities, as well as velocity derivatives, and thus vorticity, strain, and a variety of related and dynamically significant quantities. The comparison of data from the two flows allows to directly observe the influence of polymers on these quantities as well as the evolution of material elements in the presence of polymers.

  13. Turbulence of Dilute Polymer Solution

    CERN Document Server

    Xi, Heng-Dong; Xu, Haitao

    2013-01-01

    In fully developed three dimensional fluid turbulence the fluctuating energy is supplied at large scales, cascades through intermediate scales, and dissipates at small scales. It is the hallmark of turbulence that for intermediate scales, in the so called inertial range, the average energy flux is constant and independent of viscosity [1-3]. One very important question is how this range is altered, when an additional agent that can also transport energy is added to the fluid. Long-chain polymers dissolved at very small concentrations in the fluid are such an agent [4,5]. Based on prior work by de Gennes and Tabor [6,7] we introduce a theory that balances the energy flux through the turbulent cascade with that of the energy flux into the elastic degrees of freedom of the dilute long-chain polymer solution. We propose a refined elastic length scale, $r_\\varepsilon$, which describes the effect of polymer elasticity on the turbulence energy cascade. Our experimental results agree excellently with this new energy ...

  14. Tricritical points in bimodal polymer solutions

    NARCIS (Netherlands)

    Szleifer, I.; ten Brinke, G.

    1996-01-01

    The tricritical point of polymer solutions composed by two polymer homologs of different molecular weight in a solvent is studied using the single-chain mean-field theory. The tricritical point is found for a ratio of molecular weights of the two polymers r=N-1/N-2, which decreases as a function of

  15. Foaming behaviour of polymer-surfactant solutions

    Energy Technology Data Exchange (ETDEWEB)

    Cervantes-MartInez, Alfredo [Departamento de Investigacion en PolImeros y Materiales, Universidad de Sonora, Apartado Postal 130, 83000 Hermosillo, Sonora (Mexico); Maldonado, Amir [Departamento de Fisica, Universidad de Sonora, Apartado Postal 1626, 83000 Hermosillo, Sonora (Mexico)

    2007-06-20

    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.

  16. COMPUTER SIMULATION OF POLYMER SOLUTION THERMODYNAMICS

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The statistical counting method for the computer simulation of the thermodynamic quantities of polymer solution has been reviewed. The calculating results for a single athermal chain confirm the theory of the renormalization group. The results for the athermal solution are consistent with the scaling law of the osmotic pressure with the exponent 2.25. The results for a single chain with the segmental interaction are in a good agreement with the exact results obtained by the direct counting method. The results for the polymer solution show us that the Flory-Huggins parameter is strongly dependent on both the polymer concentration and the interaction energy between segments.

  17. Flow of polymer solutions through porous media

    OpenAIRE

    Denys, K.F.J.

    2003-01-01

    These days leading oil and gas producing companies are investing increasing amounts of money into the development of non-fossil energy sources like wind-, solar-, biomass energy and forestry. On the other hand these companies are persisting in developing techniques to make energy recovery more efficient intending to stretch the life span of fossil resources. One of the more mature techniques to improve recovery efficiency is polymer flooding. Herein polymer solutions are injected in injector ...

  18. Viscosity solutions for a polymer crystal growth model

    CERN Document Server

    Cardaliaguet, Pierre; Monteillet, Aurélien

    2010-01-01

    We prove existence of a solution for a polymer crystal growth model describing the movement of a front $(\\Gamma(t))$ evolving with a nonlocal velocity. In this model the nonlocal velocity is linked to the solution of a heat equation with source $\\delta_\\Gamma$. The proof relies on new regularity results for the eikonal equation, in which the velocity is positive but merely measurable in time and with H\\"{o}lder bounds in space. From this result, we deduce \\textit{a priori} regularity for the front. On the other hand, under this regularity assumption, we prove bounds and regularity estimates for the solution of the heat equation.

  19. Simulation of Fracture Nucleation in Cross-Linked Polymer Networks

    Science.gov (United States)

    Moller, J. C.; Barr, S. A.; Schultz, E. J.; Breitzman, T. D.; Berry, R. J.

    2013-02-01

    A novel atomistic simulation method is developed whereby polymer systems can undergo strain-rate-controlled deformation while bond scission is enabled. The aim is to provide insight into the nanoscale origins of fracture. Various highly cross-linked epoxy systems including various resin chain lengths and levels of nonreactive dilution were examined. Consistent with the results of physical experiments, cured resin strength increased and ductility decreased with increasing cross-link density. An analysis of dihedral angle activity shows the locations in the molecular network that are most absorptive of mechanical energy. Bond scission occurred principally at cross-link sites as well as between phenyl rings in the bisphenol moiety. Scissions typically occurred well after yield and were accompanied by steady increases in void size and dihedral angle motion between bisphenol moieties and at cross-link sites. The methods developed here could be more broadly applied to explore and compare the atomistic nature of deformation for various polymers such that mechanical and fracture properties could be tuned in a rational way. This method and its results could become part of a solution system that spans multiple length and time scales and that could more completely represent such mechanical events as fracture.

  20. Brownian particles in supramolecular polymer solutions

    NARCIS (Netherlands)

    Gucht, van der J.; Besseling, N.A.M.; Knoben, W.; Bouteiller, L.; Cohen Stuart, M.A.

    2003-01-01

    The Brownian motion of colloidal particles embedded in solutions of hydrogen-bonded supramolecular polymers has been studied using dynamic light scattering. At short times, the motion of the probe particles is diffusive with a diffusion coefficient equal to that in pure solvent. At intermediate time

  1. Extensional properties of mobile polymer solutions

    Science.gov (United States)

    Tirel, Christophe; Renoult, Marie-Charlotte; Dumouchel, Christophe; Crumeyrolle, Olivier; Lisiecki, Denis; Mutabazi, Innocent

    2016-11-01

    A deep understanding of the influence of viscoelasticity on the dynamics of liquid flows remains a challenge in the non-Newtonian fluid mechanics field. Previous work has revealed that the addition of minute amount (2.5 part per million) of high molecular weight polymer to water, forming a viscoelastic solution with strong extensional properties, modifies the fission process during droplet snap off with spectacular effects: inhibition of the singularity observed in the reference Newtonian case and formation of a long-lived (milli-second) filament. The measurement of the extensional properties for such mobile polymer solutions is one of the most pressing problem. Here, a global measurement technique, based on the multi-scale analysis of the capillary instability of a free falling jet of a mobile polymer solution, is introduced. The method of analysis allows the characterisation of the jet breakup mechanism from which the relaxation time of the polymer solution can be extracted. One of the advantages of the technique is the simple experiment it requires.

  2. 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)

  3. Brownian particles in supramolecular polymer solutions

    NARCIS (Netherlands)

    Gucht, van der J.; Besseling, N.A.M.; Knoben, W.; Bouteiller, L.; Cohen Stuart, M.A.

    2003-01-01

    The Brownian motion of colloidal particles embedded in solutions of hydrogen-bonded supramolecular polymers has been studied using dynamic light scattering. At short times, the motion of the probe particles is diffusive with a diffusion coefficient equal to that in pure solvent. At intermediate time

  4. 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...... 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...

  5. Viscosity solutions for a polymer crystal growth model

    OpenAIRE

    Cardaliaguet, Pierre; Ley, Olivier; Monteillet, Aurélien

    2011-01-01

    International audience; We prove existence of a solution for a polymer crystal growth model describing the movement of a front $(\\Gamma(t))$ evolving with a nonlocal velocity. In this model the nonlocal velocity is linked to the solution of a heat equation with source $\\delta_\\Gamma$. The proof relies on new regularity results for the eikonal equation, in which the velocity is positive but merely measurable in time and with H\\"{o}lder bounds in space. From this result, we deduce \\textit{a pri...

  6. 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

  7. 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.

  8. 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.

  9. Irreversible adsorption from concentrated polymer solutions

    Science.gov (United States)

    Auvray, Loïc; Cruz, Margerida; Auroy, Philippe

    1992-05-01

    We study the adsorption of concentrated Poly(dimethylsiloxane) (PDMS) solutions in Dichloromethane on porous silica. We vary the plymerization index N and the chain volume fraction Φ from the overlap concentration to the melt. The adsorption of PDMS on silica by hydrogen bonding is very strong and a large amount of polymer remains bound to the surface after the washing of the silica with a good solvent of the chains. We measure this quantity Γ by small angle neutron scattering. If there is no chain desorption, Γ represents the weight of polymer attached to the solid in the initial solution, which varies as the product N^{1/2} Φ^{7/8} according to a recent prediction. This relation of proportionality indeed interprets our experimental results. When the size of the chains is comparable to the pore diameter (either 500, 1 200, or 3 000 Å depending on the samples) we observe confinement effects which lower the adsorbed amount. Nous étudions d'adsorption de solutions concentrées de Poly(dimethylsiloxane) (PDMS) dans le chlorure de méthylène sur de la silice poreuse. Nous varions le degré de polymérisation N et la fraction volumique Φ des chaînes depuis la concentration de recouvrement jusqu'au fondu. L'adsorption de PDMS sur la silice par liaison hydrogène est très forte et une grande quantité de polymère reste liée à la surface après lavage de la silice par du bon solvant. Nous mesurons cette quantité Γ par diffusion centrale des neutrons. S'il n'y a pas eu désorption des chaînes, Γ représente le poids de polymère attaché au solide dans la solution initiale qui varie selon une prédiction récente comme le produit N^{1/2} Φ^{7/8}. Cette relation de proportionnalité rend effectivement compte de nos résultats. Quand la taille des chaînes est du même ordre de grandeur que le diamètre des pores (qui prend les valeurs 500, 1 200 et 3 000 Å selon les échantillons), nous observons des effets de confinement abaissant la quantité adsorbée.

  10. Reducible, dibromomaleimide-linked polymers for gene delivery.

    Science.gov (United States)

    Tan, James-Kevin Y; Choi, Jennifer L; Wei, Hua; Schellinger, Joan G; Pun, Suzie H

    2015-01-01

    Polycations have been successfully used as gene transfer vehicles both in vitro and in vivo; however, their cytotoxicity has been associated with increasing molecular weight. Polymers that can be rapidly degraded after internalization are typically better tolerated by mammalian cells compared to their non-degradable counterparts. Here, we report the use of a dibromomaleimide-alkyne (DBM-alkyne) linking agent to reversibly bridge cationic polymer segments for gene delivery and to provide site-specific functionalization by azide-alkyne cycloaddition chemistry. A panel of reducible and non-reducible, statistical copolymers of (2-dimethylamino)ethyl methacrylate (DMAEMA) and oligo(ethylene glycol)methyl ether methacrylate (OEGMA) were synthesized and evaluated. When complexed with plasmid DNA, the reducible and non-reducible polymers had comparable DNA condensation properties, sizes, and transfection efficiencies. When comparing cytotoxicity, the DBM-linked, reducible polymers were significantly less toxic than the non-reducible polymers. To demonstrate polymer functionalization by click chemistry, the DBM-linked polymers were tagged with an azide-fluorophore and were used to monitor cellular uptake. Overall, this polymer system introduces the use of a reversible linker, DBM-alkyne, to the area of gene delivery and allows for facile, orthogonal, and site-specific functionalization of gene delivery vehicles.

  11. Stationary solutions of equations of incompressible viscoelastic polymer liquid

    Science.gov (United States)

    Bambaeva, N. V.; Blokhin, A. M.

    2014-05-01

    The equations describing flows of an incompressible viscoelastic polymer liquid are studied. Stationary solutions similar to the Poiseuille and Couette solutions for the system of the Navier-Stokes equations are constructed. Stationary discontinuous solutions of the polymer liquid equation are also considered.

  12. Flow-induced phase separation in polymer solutions

    NARCIS (Netherlands)

    Moel, K. de; Flikkema, E.; Szleifer, I.; Brinke, G. ten

    1998-01-01

    A correct description of phase behaviour in polymer solutions requires a coupling between configurational statistics and thermodynamics. The effect of flow-induced chain deformation on the polymer-solvent interaction energy depends on the concentration and on the polymer architecture. It will be dem

  13. Sorption of substituted indoles on highly cross-linked polystyrene from water-acetonitrile solutions

    Science.gov (United States)

    Shafigulin, R. V.; Myakishev, A. A.; Il'Ina, E. A.; Il'in, M. M.; Davankov, V. A.; Bulanova, A. V.

    2011-07-01

    The sorption of first synthesized indole derivatives by highly cross-linked polystyrenes from water-acetonitrile solutions was studied by high-performance liquid chromatography. The retention factors and differences in the Gibbs energy of adsorption from infinite diluted solutions were calculated, and the applicability of the Snyder-Soczewinski and Scott-Kucera models for describing the chromatographic retention of sorbates on a polymer network of highly cross-linked polystyrene was shown.

  14. Gelation in Physically Associating Polymer Solutions

    Science.gov (United States)

    Kumar, Sanat

    2001-03-01

    Macromolecules, which possess moieties capable of physical association, commonly form reversible gels when dissolved in solvents. This unusual state of matter, which displays weakly elastic character at short times, is ubiquitous in contexts ranging from foods, viscosity modifiers and the cytoskeleton of living organisms. Gel formation in these systems is currently modeled by assuming that the ``sticker" pairing times are long, thus suggesting a connection to percolation concepts developed in the 1940's. We have performed computer simulations on solutions of chains with ``weak" stickers, i.e., in a realistic limit where sticker pairing energies are comparable to thermal energy, and find that gelation is not synonymous with percolation. Rather, as the temperature is lowered below a threshold value, the stickers cluster into multiplets, thus dramatically slowing the relaxation processes in these materials. The similarity of polymer physical gelation to vitrification suggests that reversible gelation and the glass transition should be describable by a common language. This view accords with recent suggestions that gelation in colloid solutions is a nonergodicity transition, comparable to the glass transition.

  15. Gelation threshold of cross-linked polymer brushes.

    Science.gov (United States)

    Hoffmann, Max; Lang, Michael; Sommer, Jens-Uwe

    2011-02-01

    The cross-linking of polymer brushes is studied using the bond-fluctuation model. By mapping the cross-linking process into a two-dimensional (2D) percolation problem within the lattice of grafting points, we investigate the gelation transition in detail. We show that the particular properties of cross-linked polymer brushes can be reduced to the distribution of bonds which are formed between the grafted chains, and we propose scaling arguments to relate the gelation threshold to the chain length and the grafting density. The gelation threshold is lower than the percolation threshold for 2D bond percolation because of the longer range and broad distribution of bonds formed by the cross-linking process. We term this type of percolation problem star percolation. We observe a broad crossover from mean-field to critical percolation behavior by analyzing the cluster size distribution near the gelation threshold.

  16. Light harvesting by dye linked conducting polymers

    Energy Technology Data Exchange (ETDEWEB)

    Troensegaard Nielsen, K.

    2006-06-15

    The fact that the fossil fuel is finite and that the detrimental long-term effects of letting CO2 into our atmosphere exist, have created an enormous interest in developing new, cheap, renewable and less polluting energy resources. One of the most obvious abundant sources of energy in the solar system is the sun. Unfortunately the well developed silicon solar cells are very costly to produce. In an attempt to produce cheap and flexible solar cells, plastic solar cells have received a lot of attention in the last decades. There are still a lot of parameters to optimize if the plastic solar cell shall be able to compete with the silicon solar cells. One of the parameters is to ensure a high degree of charge carrier separation. Charge carrier separation can only happen at heterojunctions, which cover for example the interfaces between the polymers and the electrodes or the interface between an n-conductor and a p-conductor. The facts that the charge carrier separation only happens at the heterojunctions limits the thickness of the active layer in solar cells and thereby the effectiveness of the solar cells. In this project the charge carrier separation is attempted optimized by making plastic solar cells with a molecular heterojunction. The molecular heterojunction has been obtained by synthesizing a three domain super molecular assembly termed NPN. NPN consists of two poly[1-(2,5-dioctyltolanyl)ethynylene] chains (N-domains) coupled to the [10,20-bis(3,5-bistert-butylphenyl]-5,15-dibromoporphinato]zinc(II) (P-domain). It is shown that the N domains in NPN work as effective light harvesting antennas for the P domain and effectively transfer electrically generated excitons in the N domain to the P domain. Unfortunately the P domain does not separate the charge carriers but instead works as a charge carrier trap. This results in a performance of solar cells made of NPN that is much lower than the performance of solar cells made of pure poly[1-(2,5-dioctyltolanyl

  17. Modeling of Dilute Polymer Solutions in Confined Space

    DEFF Research Database (Denmark)

    Wang, Yanwei

    2009-01-01

    by simple mathematical analyses. When the CABS method is applied to compute the equilibrium distribution (the equilibrium partition coefficient, Ko) of polymers between a dilute macroscopic solution phase and a solution confined by inert impenetrable boundaries, a sphere-like universal partitioning feature...... of polymers in SEC, one may reach a conclusion that SEC fractionates polymers based on the steric exclusion radius, Rs . The CABS method is further applied to determine the depletion profiles of dilute polymer solutions confined to a slit or near an inert wall. We show that the entire spatial density...... that (i) the depletion layer thickness, 6, is the same no matter which reference point is used to describe the depletion profile, and (ii) the value of 6 equals the steric exclusion radius, Rs , of the macromolecule in free solution. Both results hold not only for ideal polymers as has been noticed before...

  18. INTERMOLECULAR AND INTRAMOLECULAR INTERACTIONS OF POLYMER GUAR GUM IN SOLUTIONS

    Institute of Scientific and Technical Information of China (English)

    Yun-fei Yan; Hai-yang Yang; Wen-yong Liu; Ping-ping Zhu; Ping-sheng He

    2005-01-01

    The tetrahedral borate ion can crosslink with polymer guar gum in aqueous solutions. If the concentration of guar gum is less than 0.045 g/dL, the intramolecular interaction between guar gum and borate ion increases due to the formation of crosslinks. As a result, the polymer chains of guar gum in solution shrink in size and the reduced viscosity of polymer solution decreases accordingly. On the other hand, if the concentration of guar gum is greater than 0.045 g/dL, the intermolecular interaction becomes apparent due to the same reason. The polymer chains, therefore, associate together and the reduced viscosity of polymer solution increases considerably. According to this technique, the critical concentration c*,presented by de-Gennes[1], is determined successfully.

  19. Porous polymers: enabling solutions for energy applications.

    Science.gov (United States)

    Thomas, Arne; Kuhn, Pierre; Weber, Jens; Titirici, Maria-Magdalena; Antonietti, Markus

    2009-02-18

    A new generation of porous polymers was made for various energy-related applications, e.g., as fuel cell membranes, as electrode materials for batteries, for gas storage, partly from renewable resources. This review intends to catch this emerging field by reporting on a variety of different approaches to make high performing polymers porous. This includes template techniques, polymers with inherent microporosity, polymer frameworks by ionothermal polymerization, and the polymerization of carbon from appropriate precursors and by hydrothermal polymerization. In this process, we try to not only identify the current status of the field, but also point to open question and tasks to identify the potentially relevant progress.

  20. EFFECT OF ADSORPTION ON THE VISCOSITY OF DILUTE POLYMER SOLUTION

    Institute of Scientific and Technical Information of China (English)

    Rong-shi Cheng; Yu-fang Shao; Ming-zhu Liu; Rong-qing Lu

    1999-01-01

    Careful measurements of the dilute solution viscosities of polyethylene glycol and polyvinyl alcohol in water were carried out. The reduced viscosities of both polymer solutions plot upward curves at extremely dilute concentration levels similar to the phenomena observed for many polymer solutions in the early 1950's. Upon observation of the changes of the flow times of pure water in and the wall surface wettability of the viscometer after measuring solution viscosity, a view was formed that the observed viscosity abnormality at extremely dilute concentration regions is solely due to the effect of adsorption of polymer chains onto the wall surface of viscometer. A theory of adsorption effect based on the Langmuir isotherms was proposed and a mathematical analysis for data treatment was performed. The theory could adequately describe the existing viscosity data. It seems necessary to correct the viscosity result of dilute polymer solutions measured by glass capillary viscometer by taking into account the effect of adsorption in all cases.

  1. Polymer Composition and Substrate Influences on the Adhesive Bonding of a Biomimetic, Cross-Linking Polymer

    OpenAIRE

    Matos-Pérez, Cristina R.; White, James D.; Wilker, Jonathan J.

    2012-01-01

    Hierarchical biological materials such as bone, sea shells, and marine bioadhesives are providing inspiration for the assembly of synthetic molecules into complex structures. The adhesive system of marine mussels has been the focus of much attention in recent years. Several catechol-containing polymers are being developed to mimic the cross-linking of proteins containing 3,4-dihydroxyphenylalanine (DOPA) used by shellfish for sticking to rocks. Many of these biomimetic polymer systems have be...

  2. Modeling of Dilute Polymer Solutions in Confined Space

    DEFF Research Database (Denmark)

    Wang, Yanwei

    2009-01-01

    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...... of polymers in SEC, one may reach a conclusion that SEC fractionates polymers based on the steric exclusion radius, Rs . The CABS method is further applied to determine the depletion profiles of dilute polymer solutions confined to a slit or near an inert wall. We show that the entire spatial density...... that (i) the depletion layer thickness, 6, is the same no matter which reference point is used to describe the depletion profile, and (ii) the value of 6 equals the steric exclusion radius, Rs , of the macromolecule in free solution. Both results hold not only for ideal polymers as has been noticed before...

  3. Drag reduction in electro-osmosis of polymer solutions

    Science.gov (United States)

    Chang, Feng-Ming; Tsao, Heng-Kwong

    2007-05-01

    Electro-osmosis is the preferred transport mechanism in microfluidic systems. Drag reduction in electro-osmosis of polymer solutions is observed due to polymer depletion in the electric double layer (EDL). The well-known Helmholtz-Smoluchowski (HS) equation indicates that the electro-osmosis mobility is inversely proportional to the solution viscosity. For low molecular weight the polymer size (R) is smaller than the EDL thickness (λ) and the HS equation is valid. For high molecular weight (R>λ) the chains in the EDL are partially sheared and the effective viscosity is smaller than the solution viscosity. Salt addition reduces λ and can enhance drag reduction substantially.

  4. Turbulent drag reduction in dilute polymer solutions

    Science.gov (United States)

    Sreenivasan, K. R.; White, Christopher M.

    1998-11-01

    It is well known that the addition of small amounts of flexible polymers reduces drag in turbulent pipe flows. However, the underlying physics is still poorly understood. This paper will consider two aspects: The dependence of the onset of drag reduction on polymer concentration, and the so-called maximum drag reduction asymptote. The latter defines the maximum drag reduction possible for any polymer at a given Reynolds number, independent of the polymer concentration and detailed polymeric structure [1]. It is shown tentatively that a modest reworking of de Gennes' theory [2] is compatible with available experimental data. The principal element of the theory is that the polymers do not get stretched fully, but that the partially extended polymers store elastic energy and interfere with cascade mechanisms in turbulence. A conclusive understanding requires experiments in which the polymer properties that go into the theory are directly measured. [1] P.S. Virk, AIChE J., 21, 625 (1975) [2] P.G. de Gennes, Introduction to Polymer Dynamics, University of Cambridge (1990)

  5. Preparation and Characterization of a pH-Responsive Core Cross-linked Polymer Micelle

    Energy Technology Data Exchange (ETDEWEB)

    Kousaka, Shouta; Sugahara, Makoto; Endo, Tatsuya; Yusa, Shin-ichi, E-mail: yusa@eng.u-hyogo.ac.jp [Department of Materials Science and Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280 (Japan)

    2011-01-01

    Poly(ethylene glycol)-b-poly(2-(diethylamino) ethyl methacrylate-co-2-cinnamoyl-oxyethyl acrylate) (PEG-b-P(DEA/CEA)) was prepared by reversible addition-fragmentation chain transfer (RAFT) controlled radical polymerization. pH-responsive association behaviour of PEG-b-P(DEA/CEA) in 0.1 M NaCl was characterized by dynamic light scattering (DLS). As solution pH is increased from an acidic pH, the hydrodynamic radius (R{sub h}) increases, indicative of the polymer micelle formation. The formation of a micelle was also supported by static light scattering (SLS) data. The cinnamoyl groups in the core of the polymer micelle undergo photodimerization, yielding cross-links between polymer chains. The core of the polymer micelle was fixed, which was confirmed by DLS, SLS, and small angle X-ray scattering (SAXS) techniques. When pH is decreased to 3, R{sub h} of the core cross-linked (CCL) polymer micelle slightly increases due to the protonation of the DEA unit in the cross-linked core. The reversible pH-induced swelling and shrinking behaviour can be observed.

  6. 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......Many commercially important mixtures contain complex polymers, e.g. paints and coatings. If a good thermodynamic description can be given of these systems it is possible to develop paints, which possess a certain set of properties and at the same time meet some basic requirement as, e.g. regarding...

  7. Polymer fullerene solution phase behaviour and film formation pathways.

    Science.gov (United States)

    Dattani, Rajeev; Cabral, João T

    2015-04-28

    We report the phase behaviour of polymer/fullerene/solvent ternary mixtures and its consequence for the morphology of the resulting composite thin films. We focus particularly on solutions of polystyrene (PS), C60 fullerene and toluene, which are examined by static and dynamic light scattering, and films obtained from various solution ages and thermal annealing conditions, using atomic force and light microscopy. Unexpectedly, the solution phase behaviour below the polymer overlap concentration, c*, is found to be described by a simple excluded volume argument (occupied by the polymer chains) and the neat C60/solvent miscibility. Scaling consistent with full exclusion is found when the miscibility of the fullerene in the solvent is much lower than that of the polymer, giving way to partial exclusion with more soluble fullerenes (phenyl-C61-butyric acid methyl ester, PCBM) and a less asymmetric solvent (chlorobenzene), employed in photovoltaic devices. Spun cast and drop cast films were prepared from PS/C60/toluene solutions across the phase diagram to yield an identical PS/C60 composition and film thickness, resulting in qualitatively different morphologies in agreement with our measured solution phase boundaries. Our findings are relevant to the solution processing of polymer/fullerene composites (including organic photovoltaic devices), which generally require effective solubilisation of fullerene derivatives and polymer pairs in this concentration range, and the design of well-defined thin film morphologies.

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

    Science.gov (United States)

    Ma, Xin

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

  9. Mechanical stability of end-linked polymer gel

    Energy Technology Data Exchange (ETDEWEB)

    Roy Majumder, Shashwati [Theoretical Chemistry Section, Radiation Chemistry and Chemical Dynamics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Bandyopadhyay, Tusar [Theoretical Chemistry Section, Radiation Chemistry and Chemical Dynamics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)]. E-mail: btusar@barc.ernet.in; Ghosh, Swapan K. [Theoretical Chemistry Section, Radiation Chemistry and Chemical Dynamics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2005-11-01

    The mechanical stability of end-linked polymer network (gel) at large deformation has been studied with the aid of a simplified model. The model consists of square network of end-linked Hookean spring, each representing an ideal polymer chain. To mimic the structure prevailing at the gel point, the square network of springs was self-similarly repeated to generate a deterministic fractal structure having fractal dimensions, d{sub f}=1.56-1.8. For any given d{sub f}, the distribution of pores (measured by lacunarity of the network) in the structure also serves as an important parameter that characterizes the morphology of the network. Our preliminary results show that the present minimalist model qualitatively reproduces the non-monotonous structure-stability relationship, as observed in radiation-induced cross-linked polymer networks. Structures with highest lacunarity for a given fractal network have also been found to exhibit highest mechanical stability against an external deforming force before it is finally crumpled and found to form a wrinkled network.

  10. Nanostructure investigation of polymer solutions, polymer gels, and polymer thin films

    Science.gov (United States)

    Lee, Wonjoo

    This thesis discusses two systems. One is structured hydrogels which are hydrogel systems based on crosslinked poly((2-dimethylamino)ethyl methacrylate) (PDMAEMA) containing micelles which form nanoscale pores within the PDMAEMA hydrogel. The other is nanoporous block copolymer thin films where solvent selectivity is exploited to create nanopores in PS-b-P4VP thin films. Both of these are multicomponent polymer systems which have nanoscale porous structures. 1. Small angle neutron scattering of micellization of anionic surfactants in water, polymer solutions and hydrogels. Nanoporous materials have been broadly investigated due to the potential for a wide range of applications, including nano-reactors, low-K materials, and membranes. Among those, molecularly imprinted polymers (MIP) have attracted a large amount of interest because these materials resemble the "lock and key" paradigm of enzymes. MIPs are created by crosslinking either polymers or monomers in the presence of template molecules, usually in water. Initially, functional groups on the polymer or the monomer are bound either covalently or noncovalently to the template, and crosslinking results in a highly crosslinked hydrogel. The MIPs containing templates are immersed in a solvent (usually water), and the large difference in the osmotic pressure between the hydrogel and solvent removes the template molecules from the MIP, leaving pores in the polymer network containing functionalized groups. A broad range of different templates have been used ranging from molecules to nanoscale structures inclucing stereoisomers, virus, and micelles. When micelles are used as templates, the size and shape before and after crosslinking is an important variable as micelles are thermodynamic objects whose structure depends on the surfactant concentration of the solution, temperature, electrolyte concentration and polymer concentration. In our research, the first goal is to understand the micellization of anionic

  11. Electrospinning formaldehyde cross-linked zein solutions

    Science.gov (United States)

    In order to develop zein fibers with improved physical properties and solvent resistance, formaldehyde was used as the cross-linking reagent before spinning. The cross-linking reaction was carried out in either acetic acid or ethanolic-HCl where the amount of cross-linking reagent was between 1 and...

  12. Mechanism of sulfide effect on viscosity of HPAM polymer solution

    Institute of Scientific and Technical Information of China (English)

    康万利; 周阳; 王志伟; 孟令伟; 刘述忍; 白宝君

    2008-01-01

    The effect of sulfide on HPAM solution viscosity was studied using BROOKFIELD DV-II viscometer,and the interaction mechanism was discussed.The HPAM solution viscosity was investigated through fully reducing sulfide by the addition of hydrogen peroxide oxidation,and the mechanism of increasing polymer viscosity was investigated.The experimental results also show that there is a critical concentration of 15 mg/L.Below it,the loss rate of HPAM solution viscosity increases more rapidly,but becomes slowly above the critical concentration.A theoretical guidance for oilfields to prepare polymer solution using sewage-water by eliminating sulfide,and it is also importance to prepare polymer solution using sewage-water and save fresh water.

  13. Sealing of underground workings and deep boreholes by polymer solutions

    Energy Technology Data Exchange (ETDEWEB)

    Stryczek, S.; Postawa, J.; Capik, M.; Beres, J.

    1988-05-01

    Describes application and properties of Solakryl ASM 10 and Marwit S 50 polymers for rock sealing purposes in Polish underground black coal mines. Polymer powders are mixed with water and injected into boreholes to prevent spontaneous fire propagation, stop gas release from coal seams, improve mine ventilation and prevent water influx. Diagrams for gelation performance, polymerization time and solution viscosity are provided. Solutions are also mixed with filler (fly ash, gypsum) if voids and crevices are of larger volume. Density and viscosity values of polymer solution and filler mixtures relevant for pumping procedures are given. A time function for optimum Marwit concentration and volume swelling during water absorption is also derived. AzNII-cone analysis was applied for assessing solution pumpability. Examples of successful solution injection during shaft sinking by rock freezing and during fire fighting in an underground coal mine are given. 5 refs.

  14. Entrainment Reduction and Additional Dissipation in Dilute Polymer Solutions

    Science.gov (United States)

    Holzner, Markus; Lüthi, Beat; Liberzon, Alexander; Guala, Michele; Kinzelbach, Wolfgang

    We present a comparative experimental study of a turbulent flow developing in clear water and dilute polymer solutions (25 and 50 wppm polyethylene oxide). The flow is forced by a planar grid that oscillates vertically in a square container of initially still fluid. The two-component velocity fields are measured in a vertical plane passing through the center of the tank by using time resolved Particle Image Velocimetry (PIV).We obtain a lower entrainment rate for polymer solutions as compared to clear water. Extending arguments based on similarity and fractal theory to the case of dilute polymer solutions, we derive a relation between the entrainment rate and the fraction of input energy dissipated by the polymers.

  15. Solution behavior of PEO : the ultimate biocompatible polymer.

    Energy Technology Data Exchange (ETDEWEB)

    Curro, John G.; Frischknecht, Amalie Lucile

    2004-11-01

    Poly(ethylene oxide) (PEO) is the quintessential biocompatible polymer. Due to its ability to form hydrogen bonds, it is soluble in water, and yet is uncharged and relatively inert. It is being investigated for use in a wide range of biomedical and biotechnical applications, including the prevention of protein adhesion (biofouling), controlled drug delivery, and tissue scaffolds. PEO has also been proposed for use in novel polymer hydrogel nanocomposites with superior mechanical properties. However, the phase behavior of PEO in water is highly anomalous and is not addressed by current theories of polymer solutions. The effective interactions between PEO and water are very concentration dependent, unlike other polymer/solvent systems, due to water-water and water-PEO hydrogen bonds. An understanding of this anomalous behavior requires a careful examination of PEO liquids and solutions on the molecular level. We performed massively parallel molecular dynamics simulations and self-consistent Polymer Reference Interaction Site Model (PRISM) calculations on PEO liquids. We also initiated MD studies on PEO/water solutions with and without an applied electric field. This work is summarized in three parts devoted to: (1) A comparison of MD simulations, theory and experiment on PEO liquids; (2) The implementation of water potentials into the LAMMPS MD code; and (3) A theoretical analysis of the effect of an applied electric field on the phase diagram of polymer solutions.

  16. Controlling molecular ordering in solution-state conjugated polymers.

    Science.gov (United States)

    Zhu, J; Han, Y; Kumar, R; He, Y; Hong, K; Bonnesen, P V; Sumpter, B G; Smith, S C; Smith, G S; Ivanov, I N; Do, C

    2015-10-01

    Rationally encoding molecular interactions that can control the assembly structure and functional expression in a solution of conjugated polymers hold great potential for enabling optimal organic optoelectronic and sensory materials. In this work, we show that thermally-controlled and surfactant-guided assembly of water-soluble conjugated polymers in aqueous solution is a simple and effective strategy to generate optoelectronic materials with the desired molecular ordering. We have studied a conjugated polymer consisting of a hydrophobic thiophene backbone and hydrophilic, thermo-responsive ethylene oxide side groups, which shows a step-wise, multi-dimensional assembly in water. By incorporating the polymer into phase-segregated domains of an amphiphilic surfactant in solution, we demonstrate that both chain conformation and degree of molecular ordering of the conjugated polymer can be tuned in hexagonal, micellar and lamellar phases of the surfactant solution. The controlled molecular ordering in conjugated polymer assembly is demonstrated as a key factor determining the electronic interaction and optical function.

  17. Versatile solution for growing thin films of conducting polymers.

    Science.gov (United States)

    D'Arcy, Julio M; Tran, Henry D; Tung, Vincent C; Tucker-Schwartz, Alexander K; Wong, Rain P; Yang, Yang; Kaner, Richard B

    2010-11-16

    The method employed for depositing nanostructures of conducting polymers dictates potential uses in a variety of applications such as organic solar cells, light-emitting diodes, electrochromics, and sensors. A simple and scalable film fabrication technique that allows reproducible control of thickness, and morphological homogeneity at the nanoscale, is an attractive option for industrial applications. Here we demonstrate that under the proper conditions of volume, doping, and polymer concentration, films consisting of monolayers of conducting polymer nanofibers such as polyaniline, polythiophene, and poly(3-hexylthiophene) can be produced in a matter of seconds. A thermodynamically driven solution-based process leads to the growth of transparent thin films of interfacially adsorbed nanofibers. High quality transparent thin films are deposited at ambient conditions on virtually any substrate. This inexpensive process uses solutions that are recyclable and affords a new technique in the field of conducting polymers for coating large substrate areas.

  18. Linking Atomistic and Mesoscale Simulations of Water Soluble Polymers

    Science.gov (United States)

    Jones, J. L.

    2003-03-01

    There exist a range of techniques for studying surfactants and polymers in the mesoscale regime. One of the challenges is to link mesoscale theories and simulations to other calculation methods which address different length scales of the system. We introduce some mesoscale methods of calculation for polymers and surfactants and then present a case study of where mesoscale modelling is used for mechanistic understanding, by linking the method to high throughput in-silico screening methods. We look at the adsorption onto silica of ethylene oxide (EO)/ propylene oxide (PO) block copolymers (lutrols) which have been modified by end-grafting of short, cationic dimethylamino ethyl methacrylate (DMAEMA)chains. Given that the silica surface is negatively charged, it is remarkable that in some circumstances, polymers with longercationic chains have a lower adsorption. The effect is attributed to a competition between strong adsorption of the cationic DMAEMA groups driven by electrostatics, and weaker adsorption of the more numerous EO groups. This then raises the question of how we produce the values for the mesoscale parameters in these models and in the second part of the talk we describe a calculation method for doing this for water soluble polymers. The most promising route, but notoriously costly, is based on free energy calculations at the atomistic level. Free energy calculations are computationally intensive in general, but in an aqueous system one is also faced with the additional problem of using complex continuum models and/or accurate interaction potentials for water. Here we show how potential of mean force (PMF)calculations offer a practical alternative which avoids these drawbacks, though one is still faced with extremely long simulations.

  19. Submicron flow of polymer solutions: slippage reduction due to confinement.

    Science.gov (United States)

    Cuenca, Amandine; Bodiguel, Hugues

    2013-03-01

    Pressure-driven flows of high molecular weight polyacrylamide solutions are examined in nanoslits using fluorescence photobleaching. The effective viscosity of polymer solutions decreases when the channel height decreases below the micron scale. In addition, the apparent slippage of the solutions is characterized macroscopically on similar surfaces. Though slippage can explain qualitatively the effective viscosity reduction, a quantitative comparison shows that the slip length is greatly reduced below the micron scale. This result indicates that chain migration is suppressed in confined geometries.

  20. Synthesis and Solution Properties of Hydrophobic Associating Polymers

    Institute of Scientific and Technical Information of China (English)

    任鲲; 姜桂元; 徐春明; 林梅钦

    2005-01-01

    Acrylamide/2-acrylamido alkane sulfonic acid hydrophobic associating copolymers were synthesized by micellar copolymerization. Effects of hydrophobe content, polymer concentration, salinity and surfactant on rheological behavior of copolymers were investigated and the conformation of polymers in solution was studied by means of environmental scanning electronic microscopy and dynamic light scattering. The experimental results showed that in the dilute regime the hydrophobic parts could interact intramolecularly, while in the regime where the polymer concentration was higher than the critical association concentration, intermolecular hydrophobic association became predominant. Within the limit of the solubility, the critical association concentration of the polymer decreased with the increase of the salinity. The experimental results of the solution conformation indicated the presence of the three-dimensional network structure in deionized water and the size of the mesh in the network varied with the polymer concentration. In NaG1 solution, above the critical association concentration, an increase in polymer concentration enhanced the intermolecular association and also enlarged the hydrodynamic radius. It would result in the imorovement of the thickening power of polvmers.

  1. Dynamic dilution exponent in monodisperse entangled polymer solutions

    DEFF Research Database (Denmark)

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

    2017-01-01

    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...... of the long chain extremities. Then we discuss the influence of the polymer concentration on the terminal relaxation time of the solutions and how this can be modelled by the enhanced contour length fluctuation process (CR-CLF). We point out that this larger dilution effect is not only a function...... 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...

  2. Visibly transparent polymer solar cells produced by solution processing.

    Science.gov (United States)

    Chen, Chun-Chao; Dou, Letian; Zhu, Rui; Chung, Choong-Heui; Song, Tze-Bin; Zheng, Yue Bing; Hawks, Steve; Li, Gang; Weiss, Paul S; Yang, Yang

    2012-08-28

    Visibly transparent photovoltaic devices can open photovoltaic applications in many areas, such as building-integrated photovoltaics or integrated photovoltaic chargers for portable electronics. We demonstrate high-performance, visibly transparent polymer solar cells fabricated via solution processing. The photoactive layer of these visibly transparent polymer solar cells harvests solar energy from the near-infrared region while being less sensitive to visible photons. The top transparent electrode employs a highly transparent silver nanowire-metal oxide composite conducting film, which is coated through mild solution processes. With this combination, we have achieved 4% power-conversion efficiency for solution-processed and visibly transparent polymer solar cells. The optimized devices have a maximum transparency of 66% at 550 nm.

  3. A lattice Boltzmann method for dilute polymer solutions.

    Science.gov (United States)

    Singh, Shiwani; Subramanian, Ganesh; Ansumali, Santosh

    2011-06-13

    We present a lattice Boltzmann approach for the simulation of non-Newtonian fluids. The method is illustrated for the specific case of dilute polymer solutions. With the appropriate local equilibrium distribution, phase-space dynamics on a lattice, driven by a Bhatnagar-Gross-Krook (BGK) relaxation term, leads to a solution of the Fokker-Planck equation governing the probability density of polymer configurations. Results for the bulk rheological characteristics for steady and start-up shear flow are presented, and compare favourably with those obtained using Brownian dynamics simulations. The new method is less expensive than stochastic simulation techniques, particularly in the range of small to moderate Weissenberg numbers (Wi).

  4. On turbulent entrainment and dissipation in dilute polymer solutions

    Science.gov (United States)

    Liberzon, A.; Holzner, M.; Lüthi, B.; Guala, M.; Kinzelbach, W.

    2009-03-01

    We present a comparative experimental study of a turbulent flow developing in clear water and dilute polymer solutions (25 and 50 wppm polyethylene oxide). The flow is forced by a planar grid that oscillates vertically with stroke S and frequency f in a square container of initially still fluid. Two-component velocity fields are measured in a vertical plane passing through the center of the tank by using time resolved particle image velocimetry. After the forcing is initiated, a turbulent layer develops that is separated from the initially irrotational fluid by a sharp interface, the so-called turbulent/nonturbulent interface (TNTI). The turbulent region grows in time through entrainment of surrounding fluid until the fluid in the whole container is in turbulent motion. From the comparison of the experiments in clear water and polymer solutions we conclude: (i) Polymer additives modify the large scale shape of the TNTI. (ii) Both, in water and in the polymer solution the mean depth of the turbulent layer, H(t ), follows the theoretical prediction for Newtonian fluids H(t )∝√Kt , where K ∝S2f is the "grid action." (iii) We find a larger grid action for dilute polymer solutions than for water. As a consequence, the turbulent kinetic energy of the flow increases and the rate of energy input becomes higher. (iv) The entrainment rate β =ve/vrms (where ve=dH/dt is the interface propagation velocity and vrms is the root mean square of the vertical velocity) is lower for polymers (βp≈0.7) than for water (βw≈0.8). The measured values for β are in good agreement with similarity arguments, from which we estimate that in our experiment about 28% of the input energy is dissipated by polymers.

  5. Cross-linked aromatic cationic polymer electrolytes with enhanced stability for high temperature fuel cell applications

    DEFF Research Database (Denmark)

    Ma, Wenjia; Zhao, Chengji; Yang, Jingshuai

    2012-01-01

    Diamine-cross-linked membranes were prepared from cross-linkable poly(arylene ether ketone) containing pendant cationic quaternary ammonium group (QPAEK) solution by a facile and general thermal curing method using 4,4′-diaminodiphenylmethane with rigid framework and 1,6-diaminohexane with flexible...... framework as cross-linker, respectively. Self-cross-linked cationic polymer electrolytes membranes were also prepared for comparison. The diamines were advantageously distributed within the polymeric matrix and its amine function groups interacted with the benzyl bromide of QPAEK, resulting in a double...... that the diamine-cross-linked membranes using the rigid cross-linker show much improved properties than that using the flexible cross-linker. More properties relating to the feasibility in high temperature proton exchange membrane fuel cell applications were investigated in detail....

  6. Enhancement of flagellated bacterial motility in polymer solutions

    Science.gov (United States)

    Zhang, Wenyu; Sha, Sha; Pelcovits, Robert; Tang, Jay

    2015-11-01

    Measurements of the swimming speed of many species of flagellated bacteria in polymer solutions have shown that with the addition of high molecular weight polymers, the speed initially increases as a function of the kinematic viscosity. It peaks at around 1.5-2 cP with typically 10-30% higher values than in cell media without added polymers (~ 1 cP). Past the peak, the average speed gradually decreases as the solution becomes more viscous. Swimming motility persists until solution viscosity reaches 5-10 cP. Models have been proposed to account for this behavior, and the magnitude of the peak becomes a crucial test of theoretical predictions. The status of the field is complicated in light of a recent report (Martinez et al., PNAS, 2014), stressing that low-molecular weight impurities account for the peaked speed-viscosity curves in some cases. We measured the swimming speed of a uni-flagellated bacterium, caulobacter crescentus, in solutions of a number of polymers of several different sizes. Our findings confirm the peaked speed-viscosity curve, only as the molecular weight of the flexible polymers used surpassed ~ 50,000 da. The threshold molecular weight required to augment swimming speed varies somewhat with the polymer species, but it generally corresponds to radius of gyration over tens of nanometers. This general feature is consistent with the model of Powers et al. (Physics of Fluid, 2009), predicting that nonlinear viscoelasticity of the fluid enhances swimming motility. Work Supported by the NSF Fluid Physics Program (Award number CBET 1438033).

  7. Solution electrospinning of particle-polymer composite fibres

    DEFF Research Database (Denmark)

    Christiansen, Lasse; Fojan, Peter

    2016-01-01

    into scaffolds. The formation of a particle/polymer composite results in improved mechanical stability, without compromising the porosity. In the presented study, aerogel and poly(ethylene oxide) are mixed into a solution, and spun to thin fibres. Thereby a porous membrane, on the micro- and nano...

  8. Predicting morphologies of solution processed polymer: Fullerene blends

    NARCIS (Netherlands)

    Kouijzer, S.; Michels, J.J.; Berg, M. van den; Gevaerts, V.S.; Turbiez, M.; Wienk, M.M.; Janssen, R.A.J.

    2013-01-01

    The performance of solution processed polymer:fullerene thin film photovoltaic cells is largely determined by the nanoscopic and mesoscopic morphology of these blends that is formed during the drying of the layer. Although blend morphologies have been studied in detail using a variety of

  9. Predicting morphologies of solution processed polymer: Fullerene blends

    NARCIS (Netherlands)

    Kouijzer, S.; Michels, J.J.; Berg, M. van den; Gevaerts, V.S.; Turbiez, M.; Wienk, M.M.; Janssen, R.A.J.

    2013-01-01

    The performance of solution processed polymer:fullerene thin film photovoltaic cells is largely determined by the nanoscopic and mesoscopic morphology of these blends that is formed during the drying of the layer. Although blend morphologies have been studied in detail using a variety of microscopic

  10. LIQUID-LIQUID PHASE EQUILIBRIUM OF POLYMER SOLUTIONS AND POLYMER BLENDS UNDER POSITIVE AND NEGATIVE PRESSURE

    Institute of Scientific and Technical Information of China (English)

    Attila R.Imre

    2003-01-01

    In this paper we would like to give a brief review about the extensibility of the liquid-liquid locus into the negative pressure region. Negative pressure states are hardly explored; most researchers believe that the pressure scale ends at p = 0.We would like to show that this is not true, thep = 0 point is not a special point for liquids, it can be "easily" crossed. We are going to give a few example, where the extension of liquid-liquid locus for polymer blends and solutions below p = 0 gives us some interesting results, like the merging of UCST and LCST branches in weakly interacting polymer solutions or the reason why most UCST blends exhibit pressure induced immiscibility. Also, we will see what happens with the immiscibility island of aqueous polymer solutions when - reaching the critical molar mass - it "disappears".

  11. Cake Filtration in Viscoelastic Polymer Solutions

    Science.gov (United States)

    Surý, Alexander; Machač, Ivan

    2009-07-01

    In this contribution, the filtration equations for a cake filtration in viscoelastic fluids are presented. They are based on a capillary hybrid model for the flow of a power law fluid. In order to express the elastic pressure drop excess in the flow of viscoelastic filtrate through the filter cake and filter screen, modified Deborah number correction functions are included into these equations. Their validity was examined experimentally. Filtration experiments with suspensions of hardened polystyrene particles (Krasten) in viscoelastic aqueous solutions of polyacryl amides (0.4% and 0.6%wt. Kerafloc) were carried out at a constant pressure on a cylindrical filtration unit using filter screens of different resistance.

  12. 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.

  13. Polymer composition and substrate influences on the adhesive bonding of a biomimetic, cross-linking polymer.

    Science.gov (United States)

    Matos-Pérez, Cristina R; White, James D; Wilker, Jonathan J

    2012-06-06

    Hierarchical biological materials such as bone, sea shells, and marine bioadhesives are providing inspiration for the assembly of synthetic molecules into complex structures. The adhesive system of marine mussels has been the focus of much attention in recent years. Several catechol-containing polymers are being developed to mimic the cross-linking of proteins containing 3,4-dihydroxyphenylalanine (DOPA) used by shellfish for sticking to rocks. Many of these biomimetic polymer systems have been shown to form surface coatings or hydrogels; however, bulk adhesion is demonstrated less often. Developing adhesives requires addressing design issues including finding a good balance between cohesive and adhesive bonding interactions. Despite the growing number of mussel-mimicking polymers, there has been little effort to generate structure-property relations and gain insights on what chemical traits give rise to the best glues. In this report, we examine the simplest of these biomimetic polymers, poly[(3,4-dihydroxystyrene)-co-styrene]. Pendant catechol groups (i.e., 3,4-dihydroxystyrene) are distributed throughout a polystyrene backbone. Several polymer derivatives were prepared, each with a different 3,4-dihyroxystyrene content. Bulk adhesion testing showed where the optimal middle ground of cohesive and adhesive bonding resides. Adhesive performance was benchmarked against commercial glues as well as the genuine material produced by live mussels. In the best case, bonding was similar to that obtained with cyanoacrylate "Krazy Glue". Performance was also examined using low- (e.g., plastics) and high-energy (e.g., metals, wood) surfaces. The adhesive bonding of poly[(3,4-dihydroxystyrene)-co-styrene] may be the strongest of reported mussel protein mimics. These insights should help us to design future biomimetic systems, thereby bringing us closer to development of bone cements, dental composites, and surgical glues.

  14. Modeling the Rheology of Polymer Melts and Solutions

    Science.gov (United States)

    Larson, R. G.; Desai, Priyanka S.

    2015-01-01

    We review constitutive modeling of solutions and melts of linear polymers, focusing on changes in rheological behavior in shear and extensional flow as the concentration increases from unentangled dilute, to entangled, to dense melt. The rheological changes are captured by constitutive equations, prototypes of which are the FENE-P model for unentangled solutions and the DEMG model for entangled solutions and melts. From these equations, and supporting experimental data, for dilute solutions, the extensional viscosity increases with the strain rate from the low-strain rate to the high-strain rate asymptote, but in the densely entangled state, the high-strain rate viscosity is lower than the low-shear rate value, especially when orientation-dependent friction is accounted for. In shearing flow, shear thinning increases dramatically as the entanglement density increases, which can eventually lead to a shear-banding inhomogeneity. Recent improvements in constitutive modeling are paving the way for robust and accurate numerical simulations of polymer fluid mechanics and industrial processing of polymers.

  15. The Dynamics of Nanoparticles in Polymer Solutions and Melts

    Science.gov (United States)

    Mukhopadhyay, Ashis; Alam, Sharmine; Kohli, Indermeet

    2014-03-01

    Polymer nanocomposites (PNCs) has received a lot of attention in the recent years because of their potential applications in fabricating materials with novel mechanical, electrical, and photonic properties. The mobility of nanoparticles (NPs) play crucial role in determining various properties of PNC systems. Computer simulations and recent experiments have suggested that properties such as the toughness of a composite depend upon particle mobility. Even nanocomposites with ``self-healing'' properties that can restore strength in damaged regions have been proposed and some early work of their feasibility has been demonstrated. In this talk I will present some of our experimental work on the diffusion of nano-sized gold particles in polymer solutions and melt. Unusually fast diffusion of NPs when their size is smaller than the tube diameter in an entangled polymer was observed. Comparison with current theories and simulations will be shown. If time permits, our recent results on gold nanorod diffusion in polymer solution using polarized fluorescence correlation spectroscopy will be presented. Acknowledgements are made to the Donors of the American Chemical Society Petroleum Research fund (PRF # 51694-ND10) for support of this research.

  16. Dynamic contact angles in oil-aqueous polymer solutions.

    Science.gov (United States)

    Al-Shareef, Amer; Neogi, P; Bai, Baojun

    2017-01-25

    Polymer flooding is an important process in enhanced oil recovery. The displacement front is unstable when low viscosity brine displaces the heavy crude oil in the reservoir. Water-soluble polymers are added to the brine to increase its viscosity which stabilizes the displacement process. To analyze the displacement process at the micro-level, we have investigated the dynamic contact angles in silicone oil-polymer (polyethylene oxide) solution and for the first time. The dynamic contact angle is the apparent contact angle at the three-phase contact line which governs the capillary pressure, and thus is important for the displacement process. The data show no obvious signs of either shear thinning or elastic behavior, although for some systems with highest elastic effects some unexplained effects on dynamic contact angles are observed that correlate with elastic effects. Overall, dynamic contact angles are explained well using existing models for two Newtonian fluids, when the zero shear viscosity is used for the polymer solution.

  17. Instability and morphology of polymer solutions coating a fiber

    CERN Document Server

    Boulogne, François; Giorgiutti-Dauphiné, Frédérique

    2013-01-01

    We report an experimental study on the dynamics of a thin film of polymer solution coating a vertical fiber. The liquid film has first a constant thickness and then undergoes the Rayleigh-Plateau instability which leads to the formation of sequences of drops, separated by a thin film, moving down at a constant velocity. Different polymer solutions are used, i.e. xanthan solutions and polyacrylamide (PAAm) solutions. These solutions both exhibit shear-rate dependence of the viscosity, but for PAAm solutions, there are strong normal stresses in addition of the shear-thinning effect. We characterize experimentally and separately the effects of these two non-Newtonian properties on the flow on the fiber. Thus, in the flat film observed before the emergence of the drops, only shear-thinning effect plays a role and tends to thin the film compared to the Newtonian case. The effect of the non-Newtonian rheology on the Rayleigh-Plateau instability is then investigated through the measurements of the growth rate and th...

  18. 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.

  19. Azide-based cross-linking of polymers of intrinsic microporosity (PIMs) for condensable gas separation

    KAUST Repository

    Du, Naiying

    2011-03-11

    Cross-linked polymers of intrinsic microporosity (PIM)s for gas separation membranes, were prepared by a nitrene reaction from a representative PIM in the presence of two different diazide cross-linkers. The reaction temperature was optimized using TGA. The homogenous membranes were cast from THF solutions of different ratios of PIM to azides. The resulting cross-linked structures of the PIMs membranes were formed at 175 °C after 7.5 h and confirmed by TGA, XPS, FT-IR spectroscopy and gel content analysis. These resulting cross-linked polymeric membranes showed excellent gas separation performance and can be used for O 2/N 2 and CO 2/N 2 gas pairs, as well as for condensable gases, such as CO 2/CH 4, propylene/propane separation. Most importantly, and differently from typical gas separation membranes derived from glassy polymers, the crosslinked PIMs showed no obvious CO 2 plasticization up to 20 atm pressure of pure CO 2 and CO 2/CH 4 mixtures. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Measurement of cloud point temperature in polymer solutions.

    Science.gov (United States)

    Mannella, G A; La Carrubba, V; Brucato, V

    2013-07-01

    A temperature-controlled turbidity measurement apparatus for the characterization of polymer solutions has been instrumented and set up. The main features are the coupled temperature-light transmittance measurement and the accurate temperature control, achieved by means of peltier cells. The apparatus allows to measure cloud point temperatures by adopting different cooling protocols: low rate for quasi-equilibrium measurements and high rate for detect kinetic effects. A ternary polymeric solution was adopted as case study system showing that cooling rate affects the measured cloud point temperature.

  1. Structure of polymer layers adsorbed from concentrated solutions

    Science.gov (United States)

    Auvray, Loïc; Auroy, Philippe; Cruz, Margarida

    1992-06-01

    We study by neutron scattering the interfacial strucuture of poly(dimethylsiloxane) layers irreversibly adsorbed from concentrated solutions or melts. We first measure the thickness h of the layers swollen by a good solvent as a function of the chain polymerisation index N and of the polymer volume fraction in the initial solution Φ. The relation h ≈ N^{0.8}Φ^{0.3}, recently predicted from an analogy between irreversibly adsorbed layers and grafted polymer brushes, describes well our results. We can therefore deduce that there is at least one large loop of about N monomers per adsorbed chain. We also study the shape of the polymer concentration profile in the layers by measuring on two samples the polymer-solid partial structure factor, that is proportional to the Fourier transform of the profile. The model of pseudobrushes predicts a concentration decay varying with the distance of the wall z as z^{-2/5}. This power law profile accounts quantitatively for the angular variation of the polymer-solid cross structure factor but it is difficult to distinguish it without anbiguity from less singular profiles. It implies that the adsorption of PDMS onto silica is sufficiently strong and fast to quench completely the loop distribution in the initial layer. Nous étudions par diffusion de neutrons la structure interfaciale de couches de poly(diméthylsiloxane) irréversiblement adsorbées sur de la silice à partir de solutions semidiluées et de fondus. Nous mesurons d'abord l'épaisseur h des couches gonflées par un bon solvant en fonction du degré de polymérisation des chaînes N et de la fraction volumique dans la solution initiale Φ. La relation h≈ N^{0.8}Φ^{0.3} récemment prédite à partir de l'analogie entre couches irréversiblement adsorbées et brosses de polymères greffés décrit bien nos résultats. Nous en déduisons qu'il existe au moins une grande boucle d'environ N monomères par chaîne adsorbée. Nous étudions aussi la forme du profil de

  2. Optimizing end-group cross-linking polymer electrolytes for fuel cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yu Seung [Los Alamos National Laboratory; Lee, Kwan Soo [Los Alamos National Laboratory; Jeong, Myung - Hwan [GIST, KOREA; Lee, Jae - Suk [GIST, KOREA

    2009-01-01

    This paper demonstrates the optimization of proton conductivity and water uptake for cross-linkable polymer electrolytes through synthesis and characterization of end-group cross-linkable sulfonated poly(arylene ether) copolymers (ESF-BPs). The extent of reaction of cross-linking was controlled by reaction time resulting in a series of polymers with two, independent tunable parameters, degree of sulfonation (DS) and degree of cross-linking (DC). For the polymers presented, cross-linking improved proton conductivity while reducing water uptake, an uncommon trend in polymer electrolytes where water is critical for proton conduction. Other trends relating to changes are reported and the results yield insight into the role of DS and DC and how to optimize electrochemical properties and performance of polymer electrolytes through these tunable parameters. Select polymer electrolytes were tested in fuel cells where performance and durability with accelerated relative humidity cycling were compared with Nafion{reg_sign}.

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

    KAUST Repository

    Kim, Do Hwan

    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.

  4. Predicting morphologies of solution processed polymer:fullerene blends.

    Science.gov (United States)

    Kouijzer, Sandra; Michels, Jasper J; van den Berg, Mauricio; Gevaerts, Veronique S; Turbiez, Mathieu; Wienk, Martijn M; Janssen, René A J

    2013-08-14

    The performance of solution processed polymer:fullerene thin film photovoltaic cells is largely determined by the nanoscopic and mesoscopic morphology of these blends that is formed during the drying of the layer. Although blend morphologies have been studied in detail using a variety of microscopic, spectroscopic, and scattering techniques and a large degree of control has been obtained, the current understanding of the processes involved is limited. Hence, predicting the optimized processing conditions and the corresponding device performance remains a challenge. We present an experimental and modeling study on blends of a small band gap diketopyrrolopyrrole-quinquethiophene alternating copolymer (PDPP5T) and [6,6]-phenyl-C71-butyric acid methyl ester ([70]PCBM) cast from chloroform solution. The model uses the homogeneous Flory-Huggins free energy of the multicomponent blend and accounts for interfacial interactions between (locally) separated phases, based on physical properties of the polymer, fullerene, and solvent. We show that the spinodal liquid-liquid demixing that occurs during drying is responsible for the observed morphologies. The model predicts an increasing feature size and decreasing fullerene concentration in the polymer matrix with increasing drying time in accordance with experimental observations and device performance. The results represent a first step toward a predictive model for morphology formation.

  5. Using theory and simulation to link molecular features of nanoscale fillers to morphology in polymer nanocomposites

    Science.gov (United States)

    Jayaraman, Arthi; Martin, Tyler

    2014-03-01

    Polymer nanocomposites are a class of materials that consist of a polymer matrix embedded with nanoscale fillers or additives that enhance the inherent properties of the matrix polymer. To engineer polymer nanocomposites for specific applications with target macroscopic properties (e.g. photovoltaics, photonics, automobile parts) it is important to have design rules that relate molecular features to equilibrium morphology of the composite. In the first part of the talk I will present our recent theory and simulation work on composites containing polymer grafted nanoparticles, showing how polydispersity in graft and matrix polymers (physical heterogeneity) can be used to stabilize dispersion of the nanoparticles within a polymer matrix. In the second part of the talk I will present our recent work linking block-copolymer functionalization to the nanoparticle location in a polymer matrix consisting of homopolymer blends.

  6. Tuning the critical solution temperature of polymers by copolymerization

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, Bernhard; Chudoba, Richard; Dzubiella, Joachim, E-mail: joachim.dzubiella@helmholtz-berlin.de [Institut für Weiche Materie und Funktionale Materialien, Helmholtz-Zentrum Berlin, 14109 Berlin (Germany); Institut für Physik, Humboldt-Universität zu Berlin, 12489 Berlin (Germany); Heyda, Jan [Department of Physical Chemistry, University of Chemistry and Technology, Prague, 166 28 Praha 6 (Czech Republic)

    2015-12-28

    We study statistical copolymerization effects on the upper critical solution temperature (CST) of generic homopolymers by means of coarse-grained Langevin dynamics computer simulations and mean-field theory. Our systematic investigation reveals that the CST can change monotonically or non-monotonically with copolymerization, as observed in experimental studies, depending on the degree of non-additivity of the monomer (A-B) cross-interactions. The simulation findings are confirmed and qualitatively explained by a combination of a two-component Flory-de Gennes model for polymer collapse and a simple thermodynamic expansion approach. Our findings provide some rationale behind the effects of copolymerization and may be helpful for tuning CST behavior of polymers in soft material design.

  7. Microstructure of Sheared Entangled Solutions of Semiflexible Polymers

    Directory of Open Access Journals (Sweden)

    Marc Lämmel

    2016-09-01

    Full Text Available We study the influence of finite shear deformations on the microstructure and rheology of solutions of entangled semiflexible polymers theoretically and by numerical simulations and experiments with filamentous actin. Based on the tube model of semiflexible polymers, we predict that large finite shear deformations strongly affect the average tube width and curvature, thereby exciting considerable restoring stresses. In contrast, the associated shear alignment is moderate, with little impact on the average tube parameters, and thus expected to be long-lived and detectable after cessation of shear. Similarly, topologically preserved hairpin configurations are predicted to leave a long-lived fingerprint in the shape of the distributions of tube widths and curvatures. Our numerical and experimental data support the theory.

  8. Adsorption of catechol from aqueous solution by aminated hypercrosslinked polymers

    Institute of Scientific and Technical Information of China (English)

    SUN Yue; LI Xiao-tao; XU Chao; CHEN Jin-long; LI Ai-min; ZHANG Quan-xing

    2005-01-01

    Adsorption of catechol from aqueous solution with the hypercrosslinked polymeric adsorbent NDA-100 and its derivatives AH-1,AH-2 and AH-3 aminated by dimethylamine, the commercial resin Amberlite XAD-4 and weakly basic anion exchanger resin D301 was compared. It was found that the aminated hypercrosslinked resins had the highest adsorption capacities among the tested polymers. The empirical Freundlich equation was successfully employed to describe the adsorption process. Specific surface area and micropore structure of the adsorbent, in company with tertiary amino groups on matrix affected the adsorption performance towards catechol. In addition,thermodynamic study was carried out to interpret the adsorption mechanism. Kinetic study testified that the tertiary amino groups on the polymer matrix could decrease the adsorption rate and increase the adsorption apparent activation energy.

  9. Concurrent solution-like decoloration rate and high mechanical strength from polymer-dispersed photochromic organogel.

    Science.gov (United States)

    Long, Shijun; Bi, Shuguang; Liao, Yonggui; Xue, Zhigang; Xie, Xiaolin

    2014-04-01

    To achieve a fast photochromic response in solid matrix, photochromic molecules/segments have been either dispersed into elastomers via physical doping or linked to glassy polymers by soft units through covalent bonding. However, the former is lack of high mechanical strength and the latter owes the drawback of time-consumption of synthesis. Here, we propose a facile strategy of co-solvent evaporation to prepare polymer-dispersed photochromic organogel where both high mechanical strength of the glassy polymer matrix and solution-like fast photochromism of the photochromic molecule within organogel can be retained concurrently. Glassy PVA matrix and dispersed organogel of 1,3:2,4-di-O-benzylidene-d-sorbitol/poly(propylene glycol) (DBS/PPG) provide high mechanical strength and sufficient free volume for intramolecular rotation of photochromic spiropyran (SP), respectively. Interestingly, these thin films behave a solution-like decoloration the decay rate of which is 65-70 fold faster than that in the SP-directly doped PVA film and only slightly slower than those in their corresponding PPG solutions.

  10. Theory of DNA electrophoresis in physical gels and entangled polymer solutions

    Science.gov (United States)

    Duke, Thomas; Viovy, Jean Louis

    1994-03-01

    A scaling theory is presented for the electrophoretic mobility of DNA in sieving media that form dynamically evolving meshworks, such as physical gels and solutions of entangled polymers. In such media, the topological constraints on the DNA's motion are perpetually changing as cross links break and rejoin or as the polymers diffuse. It is shown that if the rate of constraint release falls within a certain range (which depends on the field strength), fractionation can be extended to higher molecular weights than would be feasible using a permanent gel of equivalent pore size. This improvement is a consequence of the disruptive effect that constraint release has on the mechanism of molecular orientation. Numerical simulations support the predictions of the theory. The possibility of realizing such a system in practice, with the aim of improving on current electrophoresis methods, is commented upon. It is suggested that semidilute polymer solutions may be a versatile medium for the rapid separation of long single-stranded DNA molecules, and the particular quality of solution required is identified.

  11. Foaming and foam stability for mixed polymer-surfactant solutions: effects of surfactant type and polymer charge.

    Science.gov (United States)

    Petkova, R; Tcholakova, S; Denkov, N D

    2012-03-20

    Solutions of surfactant-polymer mixtures often exhibit different foaming properties, compared to the solutions of the individual components, due to the strong tendency for formation of polymer-surfactant complexes in the bulk and on the surface of the mixed solutions. A generally shared view in the literature is that electrostatic interactions govern the formation of these complexes, for example between anionic surfactants and cationic polymers. In this study we combine foam tests with model experiments to evaluate and explain the effect of several polymer-surfactant mixtures on the foaminess and foam stability of the respective solutions. Anionic, cationic, and nonionic surfactants (SDS, C(12)TAB, and C(12)EO(23)) were studied to clarify the role of surfactant charge. Highly hydrophilic cationic and nonionic polymers (polyvinylamine and polyvinylformamide, respectivey) were chosen to eliminate the (more trivial) effect of direct hydrophobic interactions between the surfactant tails and the hydrophobic regions on the polymer chains. Our experiments showed clearly that the presence of opposite charges is not a necessary condition for boosting the foaminess and foam stability in the surfactant-polymer mixtures studied. Clear foam boosting (synergistic) effects were observed in the mixtures of cationic surfactant and cationic polymer, cationic surfactant and nonionic polymer, and anionic surfactant and nonionic polymer. The mixtures of anionic surfactant and cationic polymer showed improved foam stability, however, the foaminess was strongly reduced, as compared to the surfactant solutions without polymer. No significant synergistic or antagonistic effects were observed for the mixture of nonionic surfactant (with low critical micelle concentration) and nonionic polymer. The results from the model experiments allowed us to explain the observed trends by the different adsorption dynamics and complex formation pattern in the systems studied.

  12. Solution and Melt Rheology of Polypropylene Comb and Star Polymers

    Science.gov (United States)

    Ghosh, Arnav; Colby, Ralph H.; Rose, Jeffrey M.; Cherian, Anna E.; Coates, Geoffrey W.

    2006-03-01

    Syndiotactic polypropylene macromonomer arms have been prepared by coordination-insertion polymerization. These arms have been made into polypropylene star polymers by the homopolymerization of the syndiotactic arms with a living alkene polymerization catalyst. The macromonomer arms have also been randomly copolymerized with propylene using rac-dimethylsilyl(2-methyl-4-phenylindenyl) zirconium dichloride catalysts to make polypropylene combs. Consequently we have star polymers and a series of comb polymers with different backbone lengths that are all made from the same macromonomer arms. We compare linear viscoelastic data on star and comb polypropylene melts and solutions in squalane to predictions of the tube dilation model and the tube model without tube dilation. The ratio of comb terminal relaxation time to star terminal relaxation time eliminates the friction coefficient and allows determination of the extent of tube dilation the backbone experiences when it relaxes. The concentration dependence of the comb/star terminal relaxation time ratio can be described by either model, owing to adjustable parameters that are not known apriori, so independent means to evaluate those parameters will be discussed.

  13. Core Cross-Linked Multiarm Star Polymers with Aggregation-Induced Emission and Temperature Responsive Fluorescence Characteristics

    KAUST Repository

    Zhang, Zhen

    2017-05-19

    Aggregation-induced emission (AIE) active core cross-linked multiarm star polymers, carrying polystyrene (PS), polyethylene (PE), or polyethylene-b-polycaprolactone (PE-b-PCL) arms, have been synthesized through an “arm-first” strategy, by atom transfer radical copolymerization (ATRP) of a double styrene-functionalized tetraphenylethene (TPE-2St) used as a cross-linker with linear arm precursors possessing terminal ATRP initiating moieties. Polyethylene macroinitiator (PE–Br) was prepared via the polyhomologation of dimethylsulfoxonium methylide with triethylborane followed by oxidation/hydrolysis and esterification of the produced PE–OH with 2-bromoisobutyryl bromide; polyethylene-block-poly(ε-caprolactone) diblock macroinitiator was derived by combining polyhomologation with ring-opening polymerization (ROP). All synthesized star polymers showed AIE-behavior either in solution or in bulk. At high concentration in good solvents (e.g., THF, or toluene) they exhibited low photoluminescence (PL) intensity due to the inner filter effect. In sharp contrast to the small molecule TPE-2St, the star polymers were highly emissive in dilute THF solutions. This can be attributed to the cross-linked structure of poly(TPE-2St) core which restricts the intramolecular rotation and thus induces emission. In addition, the PL intensity of PE star polymers in THF(solvent)/n-hexane(nonsolvent) mixtures, due to their nearly spherical shape, increased when the temperature decreased from 55 to 5 °C with a linear response in the range 40–5 °C.

  14. Synthesis, characterisation, and evaluation of a cross-linked disulphide amide-anhydride-containing polymer based on cysteine for colonic drug delivery.

    Science.gov (United States)

    Lim, Vuanghao; Peh, Kok Khiang; Sahudin, Shariza

    2013-12-18

    The use of disulphide polymers, a low redox potential responsive delivery, is one strategy for targeting drugs to the colon so that they are specifically released there. The objective of this study was to synthesise a new cross-linked disulphide-containing polymer based on the amino acid cysteine as a colon drug delivery system and to evaluate the efficiency of the polymers for colon targeted drug delivery under the condition of a low redox potential. The disulphide cross-linked polymers were synthesised via air oxidation of 1,2-ethanedithiol and 3-mercapto-N-2-(3-mercaptopropionamide)-3-mercapto propionic anhydride (trithiol monomers) using different ratio combinations. Four types of polymers were synthesised: P10, P11, P151, and P15. All compounds synthesised were characterised by NMR, IR, LC-MS, CHNS analysis, Raman spectrometry, SEM-EDX, and elemental mapping. The synthesised polymers were evaluated in chemical reduction studies that were performed in zinc/acetic acid solution. The suitability of each polymer for use in colon-targeted drug delivery was investigated in vitro using simulated conditions. Chemical reduction studies showed that all polymers were reduced after 0.5-1.0 h, but different polymers had different thiol concentrations. The bacterial degradation studies showed that the polymers were biodegraded in the anaerobic colonic bacterial medium. Degradation was most pronounced for polymer P15. This result complements the general consensus that biodegradability depends on the swellability of polymers in an aqueous environment. Overall, these results suggest that the cross-linked disulphide-containing polymers described herein could be used as coatings for drugs delivered to the colon.

  15. Synthesis, Characterisation, and Evaluation of a Cross-Linked Disulphide Amide-Anhydride-Containing Polymer Based on Cysteine for Colonic Drug Delivery

    Directory of Open Access Journals (Sweden)

    Vuanghao Lim

    2013-12-01

    Full Text Available The use of disulphide polymers, a low redox potential responsive delivery, is one strategy for targeting drugs to the colon so that they are specifically released there. The objective of this study was to synthesise a new cross-linked disulphide-containing polymer based on the amino acid cysteine as a colon drug delivery system and to evaluate the efficiency of the polymers for colon targeted drug delivery under the condition of a low redox potential. The disulphide cross-linked polymers were synthesised via air oxidation of 1,2-ethanedithiol and 3-mercapto-N-2-(3-mercaptopropionamide-3-mercapto propionic anhydride (trithiol monomers using different ratio combinations. Four types of polymers were synthesised: P10, P11, P151, and P15. All compounds synthesised were characterised by NMR, IR, LC-MS, CHNS analysis, Raman spectrometry, SEM-EDX, and elemental mapping. The synthesised polymers were evaluated in chemical reduction studies that were performed in zinc/acetic acid solution. The suitability of each polymer for use in colon-targeted drug delivery was investigated in vitro using simulated conditions. Chemical reduction studies showed that all polymers were reduced after 0.5–1.0 h, but different polymers had different thiol concentrations. The bacterial degradation studies showed that the polymers were biodegraded in the anaerobic colonic bacterial medium. Degradation was most pronounced for polymer P15. This result complements the general consensus that biodegradability depends on the swellability of polymers in an aqueous environment. Overall, these results suggest that the cross-linked disulphide-containing polymers described herein could be used as coatings for drugs delivered to the colon.

  16. Perovskite/polymer solar cells prepared using solution process

    Science.gov (United States)

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

    2016-11-01

    We report a simple solution-based process to fabricate a perovskite/polymer tandem solar cell using inorganic CH3NH3PM3 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 CH3NH3I (methyl ammonium iodide) with PbI2 (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/cm2 at 25 °C comprised of an open circuit voltage of 0.31 V, a short circuit current density of 2.53 mA/cm2, and a power conversion efficiency of 0.42%.

  17. 5,10-linked naphthodithiophenes as the building block for semiconducting polymers

    Science.gov (United States)

    Osaka, Itaru; Komatsu, Koki; Koganezawa, Tomoyuki; Takimiya, Kazuo

    2014-04-01

    We present new semiconducting polymers incorporating naphtho[1, 2-b:5, 6-b‧] dithiophene (NDT3) and naphtho[2, 1-b:6, 5-b‧] dithiophene (NDT4), which are linked at the naphthalene positions, in the polymer backbone. It is interesting that the trend in the ordering structure and thus charge transport properties are quite different from what were observed in the isomeric polymers where the NDT3 and NDT4 cores are linked at the thiophene α-positions. In the thiophene-linked NDT system, the NDT3-based polymer (PNDT3BT) gave the better ordering in thin films and thus the high charge carrier mobility compared to the NDT4-based polymer (PNDT4BT). In the meantime, in the naphthalene-linked NDT system, the NDT4-based polymer (PNDT4iBT) provided the superior properties. Considering that PNDT4iBT has relatively low highest occupied molecular orbital (HOMO) energy level (-5.2 eV) and moderately high mobilities in the order of 10-2 cm2 V-1 s-1, the NDT4 core, when linked at the naphthalene positions, can be a good building unit for the development of high-performance semiconducting polymers for both organic field-effect transistors and photovoltaic devices.

  18. 5,10-linked naphthodithiophenes as the building block for semiconducting polymers

    Directory of Open Access Journals (Sweden)

    Itaru Osaka

    2014-04-01

    Full Text Available We present new semiconducting polymers incorporating naphtho[1, 2-b:5, 6-b'] dithiophene (NDT3 and naphtho[2, 1-b:6, 5-b'] dithiophene (NDT4, which are linked at the naphthalene positions, in the polymer backbone. It is interesting that the trend in the ordering structure and thus charge transport properties are quite different from what were observed in the isomeric polymers where the NDT3 and NDT4 cores are linked at the thiophene α-positions. In the thiophene-linked NDT system, the NDT3-based polymer (PNDT3BT gave the better ordering in thin films and thus the high charge carrier mobility compared to the NDT4-based polymer (PNDT4BT. In the meantime, in the naphthalene-linked NDT system, the NDT4-based polymer (PNDT4iBT provided the superior properties. Considering that PNDT4iBT has relatively low highest occupied molecular orbital (HOMO energy level (−5.2 eV and moderately high mobilities in the order of 10−2 cm2 V−1 s−1, the NDT4 core, when linked at the naphthalene positions, can be a good building unit for the development of high-performance semiconducting polymers for both organic field-effect transistors and photovoltaic devices.

  19. Quantitative Modeling of Entangled Polymer Rheology: Experiments, Tube Models and Slip-Link Simulations

    Science.gov (United States)

    Desai, Priyanka Subhash

    Rheology properties are sensitive indicators of molecular structure and dynamics. The relationship between rheology and polymer dynamics is captured in the constitutive model, which, if accurate and robust, would greatly aid molecular design and polymer processing. This dissertation is thus focused on building accurate and quantitative constitutive models that can help predict linear and non-linear viscoelasticity. In this work, we have used a multi-pronged approach based on the tube theory, coarse-grained slip-link simulations, and advanced polymeric synthetic and characterization techniques, to confront some of the outstanding problems in entangled polymer rheology. First, we modified simple tube based constitutive equations in extensional rheology and developed functional forms to test the effect of Kuhn segment alignment on a) tube diameter enlargement and b) monomeric friction reduction between subchains. We, then, used these functional forms to model extensional viscosity data for polystyrene (PS) melts and solutions. We demonstrated that the idea of reduction in segmental friction due to Kuhn alignment is successful in explaining the qualitative difference between melts and solutions in extension as revealed by recent experiments on PS. Second, we compiled literature data and used it to develop a universal tube model parameter set and prescribed their values and uncertainties for 1,4-PBd by comparing linear viscoelastic G' and G" mastercurves for 1,4-PBds of various branching architectures. The high frequency transition region of the mastercurves superposed very well for all the 1,4-PBds irrespective of their molecular weight and architecture, indicating universality in high frequency behavior. Therefore, all three parameters of the tube model were extracted from this high frequency transition region alone. Third, we compared predictions of two versions of the tube model, Hierarchical model and BoB model against linear viscoelastic data of blends of 1,4-PBd

  20. MECHANISM FOR VISCOELASTIC POLYMER SOLUTION PERCOLATING THROUGH POROUS MEDIA

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li-juan; YUE Xiang-an

    2007-01-01

    The pore throat of porous media is modeled as a constricted channel or expanded channel. The flow of viscoelastic polymer solution in pore throat model is studied by numerical method. Relationship between pressure drop and flow rate is developed, viscoelasticity and throat size are found to be two main factors in high flow resistance. According to pore throat model, 2-D stochastic channel bundle is put forward to model porous media, which is composed of pore throat models in series - parallel connection with size and length accord to Haring - Greenkorn stochastic distribution. Percolation model of viscoelastic fluid is developed on the basis of Darcy equation and pressure drop vs. flow rate relation in 2-D stochastic channel bundle. Results indicate that the seepage ability of viscoelastic polymer solution decreases with the increase of viscoelasticity, injection rate, and heterogeneity as well as the decrease of mean pore size of porous media. The high pressure drop of viscoelastic fluid at the connection of pore to throat plays a great role in its anomalous high flow resistance through porous media.

  1. Theoretical analysis of microscopic oil displacement mechanism by viscoelastic polymer solution

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The microscopic oil displacement mechanism in viscoelastic polymer flooding is theoretically analyzed with mechanical method.The effects of viscoelasticity of polymer solution on such three kinds of residual oil as in pore throat,in sudden expansion pore path,and in dead end are analyzed.Results show that the critical radius of mobile residual oil for viscoelastic polymer solution is larger than that for viscous polymer solution,which makes the oil that is immobile in viscous polymer flooding displaced u...

  2. DIFFUSION COEFFICIENTS IN POLYMER-SOLVENT SYSTEMS FOR HIGHLY CONCENTRATED POLYMER SOLUTIONS

    Directory of Open Access Journals (Sweden)

    R.A. Reis

    2001-12-01

    Full Text Available The Vrentas/Duda proposal for the diffusion of polymer-solvent systems, which is based on the free-volume theory, was employed in correlating and predicting mutual diffusion coefficients in highly concentrated polymer solutions. It has been observed that the predictive version of the model is capable of qualitatively representing the experimental data, while the use of an adjustable parameter greatly improves the performance of the model. The systems studied were poly(vinyl acetate-toluene and Neoprene-acetone, and a comparison between experimental data and calculated values from the Vrentas/Duda model is reported. A new experimental apparatus based on the sorption technique was built to provide reliable diffusivity data on the Neoprene-acetone system.

  3. Investigation of anisotropic thermal transport in cross-linked polymers

    Science.gov (United States)

    Simavilla, David Nieto

    Thermal transport in lightly cross-linked polyisoprene and polybutadine subjected to uniaxial elongation is investigated experimentally. We employ two experimental techniques to assess the effect that deformation has on this class of materials. The first technique, which is based on Forced Rayleigh Scattering (FRS), allows us to measure the two independent components of the thermal diffusivity tensor as a function of deformation. These measurements along with independent measurements of the tensile stress and birefringence are used to evaluate the stress-thermal and stress-optic rules. The stress-thermal rule is found to be valid for the entire range of elongations applied. In contrast, the stress-optic rule fails for moderate to large stretch ratios. This suggests that the degree of anisotropy in thermal conductivity depends on both orientation and tension in polymer chain segments. The second technique, which is based on infrared thermography (IRT), allows us to measure anisotropy in thermal conductivity and strain induced changes in heat capacity. We validate this method measurements of anisotropic thermal conductivity by comparing them with those obtained using FRS. We find excellent agreement between the two techniques. Uncertainty in the infrared thermography method measurements is estimated to be about 2-5 %. The accuracy of the method and its potential application to non-transparent materials makes it a good alternative to extend current research on anisotropic thermal transport in polymeric materials. A second IRT application allows us to investigate the dependence of heat capacity on deformation. We find that heat capacity increases with stretch ratio in polyisoprene specimens under uniaxial extension. The deviation from the equilibrium value of heat capacity is consistent with an independent set of experiments comparing anisotropy in thermal diffusivity and conductivity employing FRS and IRT techniques. We identify finite extensibility and strain

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

    Science.gov (United States)

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

    2011-01-01

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

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

    Science.gov (United States)

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

    2014-04-01

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

  6. Phosphorylcholine substituted polyolefins: New syntheses, solution assemblies, and polymer vesicles

    Science.gov (United States)

    Kratz, Katrina A.

    This thesis describes the synthesis and applications of a new series of amphiphilic homopolymers and copolymers consisting of hydrophobic polyolefin backbone and hydrophilic phosphorylcholine (PC) pendant groups. These polymers are synthesized by ring opening metathesis polymerization (ROMP) of a novel PC- cyclooctene monomer, and copolymerization of various functionalized cyclooctene comonomers. Incorporation of different comonomers into the PC-polyolefin backbone affords copolymers with different functionalities, including crosslinkers, fluorophores, and other reactive groups, that tune the range of applications of these polymers, and their hydrophobic/hydrophilic balance. The amphiphilic nature of PC-polyolefins was exploited in oil-water interfacial assembly, providing robust polymer capsules to encapsulate and deliver nanoparticles to damaged regions of a substrate in a project termed `repair-and-go.' In repair-and-go, a flexible microcapsule filled with a solution of nanoparticles probes an imperfection-riddled substrate as it rolls over the surface. The thin capsule wall allows the nanoparticles to escape the capsules and enter into the cracks, driven in part by favorable interactions between the nanoparticle ligands and the cracked surface (i.e., hydrophobic-hydrophobic interactions). The capsules then continue their transport along the surface, filling more cracks and depositing particles into them. The amphiphilic nature of PC-polyolefins was also exploited in aqueous assembly, forming novel polymer vesicles in water. PC-polyolefin vesicles ranged in size from 50 nm to 30 µm. The mechanical properties of PC-polyolefin vesicles were measured by micropipette aspiration techniques, and found to be more robust than conventional liposomes or polymersomes prepared from block copolymers. PC-polyolefin vesicles have potential use in drug delivery; it was found that the cancer drug doxorubicin could be encapsulated efficiently in PC-polyolefin vesicles. In

  7. Designing of superporous cross-linked hydrogels containing acrylic-based polymer network

    Directory of Open Access Journals (Sweden)

    Ray Debajyoti

    2008-01-01

    Full Text Available Biodegradable cross-linked polymer, 2-hydroxyethyl methacrylate-co-acrylic acid was synthesized by free radical polymerization technique using N,N"-methylene-bis-acrylamide as cross-linker and benzoyl peroxide as reaction initiator. FT-IR, 1 H-NMR, scanning electron microscopy (SEM, and thermogravimetric analysis (TGA studies of the copolymer along with homopolymers were carried out. FT-IR studies showed no interactions on copolymerization. SEM studies of the copolymer were carried out and mean particle size was found to be 50 µm. TGA analysis indicated an increase in thermal stability by cross-linking the polymer network. Swelling behavior of the copolymer showed more swelling by increasing pH of the medum and the prepared polymer was found to be biodegradable. The prepared cross-linked polymer system holds good for further drug delivery studies in connection to its super swelling and biodegradability.

  8. Low-density, polymer foams as structural models for phase-separation in polymer solutions

    Energy Technology Data Exchange (ETDEWEB)

    Beaucage, G. [Univ. of Cincinnati, OH (United States); Lagasse, R.R.; Aubert, J.H. [Sandia National Labs., Albuquerque, NM (United States)] [and others

    1995-12-31

    Low density polymer foams are produced through nano-scale phase separation of 5 to 15% solutions yielding gels. The gels are solvent exchanged and dried by supercritical extraction. We have found that the morphology of the phase separated gel, the intermediate solvent exchanged gels and the final foams are essentially identical over a wide range of size. Through the combination of several scattering techniques covering many decades of size we can distinguish structural levels in these low-density foams. The combined scattering data spans sizes ranging from 10{mu}m to 1{Angstrom}. A recently developed global fitting approach can describe the multiple levels of structure observed in these complex materials. Several morphological classes of foams are observed. A perplexing feature in the scattering patterns from all of the foams is a 3-dimensional structure with a radius of gyration from 40 to 100{Angstrom}. By variation of the polymer molecular-weight, scattering data supports a model describing this nano-scale structure as partially isolated, collapsed polymer coils. This model indicates that collapsed base structural unit in these morphologies.

  9. 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.

  10. The adsorption of surfactant at the amorphous polymer solution interface

    CERN Document Server

    Gilchrist, V A

    2001-01-01

    Adsorption of surfactants onto amorphous polymers at the solid-solution interface is of direct relevance to many industrial sectors ranging from food, pharmaceuticals, paints, paper and photographic colour films. Although it is widely accepted that surfactants play the underpinning role in these applications, little is currently understood about the interactions between surfactants and polymeric materials at the molecular level. This lack of progress is mainly due to the inability of most existing techniques in probing this type of structural information at the wet interface. Specular neutron reflection (SNR) is a recently developed technique capable of detecting structural information with resolution down to a few angstroms (A). When combined with deuterium labeling, it is possible to distinguish the surfactant from the polymeric species at the interface. The aim of this work is to explore the appropriate experimental approach that utilizes the potential of neutron reflection to unravel molecular information...

  11. 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

  12. SOLUTION PROPERTIES OF LADDER-LIKE POLYMER POLYPHENYLSILSESQUIOXANES

    Institute of Scientific and Technical Information of China (English)

    SHI Lianghe; ZHANG Xinsheng; SI Yuandong; YE Meiling; LI Dingcai

    1987-01-01

    Solution properties of ladder-like polymer polyphenylsilsesquioxane (PPS) were studied by measurement of intrinsic viscosity, small angle laser light scattering and gel permeation chromatography. It was found that PPS can be modeled with a wormlike continuous cylinder rather than a wormlike coil. A plot of (M2/[η])1/3 vs. M1/2 was employed in obtaining the persistence length (2λ)-1 and effective hydrodynamic diameter. When MW≤5 × 105, Mark-Houwink equation is adequate in describing the relationship between MW and [η] with α about unity. This implies that PPS chain is semi-stiff. For GPC experiments, it was shown that universal calibration can be applied in PPS. When molecular weights of PPS are sufficiently high, their molecular weight distributions are often very broad.

  13. Ordering phenomena of star polymer solutions approaching the Θ state

    Science.gov (United States)

    Likos, C. N.; Löwen, H.; Poppe, A.; Willner, L.; Roovers, J.; Cubitt, B.; Richter, D.

    1998-11-01

    The liquid-state ordering phenomena of a semidilute polybutadiene 64-arm star polymer solution were investigated by small-angle neutron scattering. For this purpose, we used deuterated 1,4-dioxane, which is a Θ solvent for the star at 31.5 °C. Its quality was modified by varying the temperature in the range between 40 °C and 80 °C. Besides a swelling of the star, with increasing temperature the development of a strong correlation peak was observed in the experiment. The experimental data were described theoretically by employing an effective pair potential between stars which was introduced earlier by Mewis et al. [J. Mewis, W. J. Frith, T. A. Strivens, and W. B. Russel, AIChE J. 35, 415 (1989)].

  14. Engineering solutions for polymer composites solar water heaters production

    Science.gov (United States)

    Frid, S. E.; Arsatov, A. V.; Oshchepkov, M. Yu.

    2016-06-01

    Analysis of engineering solutions aimed at a considerable decrease of solar water heaters cost via the use of polymer composites in heaters construction and solar collector and heat storage integration into a single device representing an integrated unit results are considered. Possibilities of creating solar water heaters of only three components and changing welding, soldering, mechanical treatment, and assembly of a complicate construction for large components molding of polymer composites and their gluing are demonstrated. Materials of unit components and engineering solutions for their manufacturing are analyzed with consideration for construction requirements of solar water heaters. Optimal materials are fiber glass and carbon-filled plastics based on hot-cure thermosets, and an optimal molding technology is hot molding. It is necessary to manufacture the absorbing panel as corrugated and to use a special paint as its selective coating. Parameters of the unit have been optimized by calculation. Developed two-dimensional numerical model of the unit demonstrates good agreement with the experiment. Optimal ratio of daily load to receiving surface area of a solar water heater operating on a clear summer day in the midland of Russia is 130‒150 L/m2. Storage tank volume and load schedule have a slight effect on solar water heater output. A thermal insulation layer of 35‒40 mm is sufficient to provide an efficient thermal insulation of the back and side walls. An experimental model layout representing a solar water heater prototype of a prime cost of 70‒90/(m2 receiving surface) has been developed for a manufacturing volume of no less than 5000 pieces per year.

  15. ROMP-based thermosetting polymers from modified castor oil with various cross-linking agents

    Science.gov (United States)

    Ding, Rui

    Polymers derived from bio-renewable resources are finding an increase in global demand. In addition, polymers with distinctive functionalities are required in certain advanced fields, such as aerospace and civil engineering. In an attempt to meet both these needs, the goal of this work aims to develop a range of bio-based thermosetting matrix polymers for potential applications in multifunctional composites. Ring-opening metathesis polymerization (ROMP), which recently has been explored as a powerful method in polymer chemistry, was employed as a unique pathway to polymerize agricultural oil-based reactants. Specifically, a novel norbornyl-functionalized castor oil alcohol (NCA) was investigated to polymerize different cross-linking agents using ROMP. The effects of incorporating dicyclopentadiene (DCPD) and a norbornene-based crosslinker (CL) were systematically evaluated with respect to curing behavior and thermal mechanical properties of the polymers. Isothermal differential scanning calorimetry (DSC) was used to investigate the conversion during cure. Dynamic DSC scans at multiple heating rates revealed conversion-dependent activation energy by Ozawa-Flynn-Wall analysis. The glass transition temperature, storage modulus, and loss modulus for NCA/DCPD and NCA/CL copolymers with different cross-linking agent loading were compared using dynamic mechanical analysis. Cross-link density was examined to explain the very different dynamic mechanical behavior. Mechanical stress-strain curves were developed through tensile test, and thermal stability of the cross-linked polymers was evaluated by thermogravimetric analysis to further investigate the structure-property relationships in these systems.

  16. Solution and Diffusion Behavior of Pure Gases and Gas Mixtures in Glassy Polymer Membranes

    Institute of Scientific and Technical Information of China (English)

    庄震万; 卫伟; 时钧

    1994-01-01

    A general model for the solution and diffusion behavior in pure gas-polymer membrane systems and gas mixture-polymer membrane systems has been developed. Proved by experiments on different glassy and rubbery polymer membranes at various temperatures and pressures, this model can achieve the prediction of permeation behavior of pure gases and gas mixtures in polymer membranes only using the model parameters obtained from experiments on pure gases. The calculated results are in good agreement with experimental.

  17. 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.

  18. Vapor-liquid equilibria of polymer solutions determined by molecular mechanics

    DEFF Research Database (Denmark)

    Jonsdottir, Svava Osk; Rasmussen, Kjeld; Rasmussen, Peter

    1998-01-01

    A method of calculating interaction parameters used in phaseequilibrium calculations has been extended for predicting solventactivities of polymer solutions. A pair of interaction parameters aredetermined by calculating interaction energies between all pairs ofmolecules in the solution of interest...

  19. Vapor-liquid equilibria of polymer solutions determined by molecular mechanics

    DEFF Research Database (Denmark)

    Jonsdottir, Svava Osk; Rasmussen, Kjeld; Rasmussen, Peter;

    1998-01-01

    A method of calculating interaction parameters used in phaseequilibrium calculations has been extended for predicting solventactivities of polymer solutions. A pair of interaction parameters aredetermined by calculating interaction energies between all pairs ofmolecules in the solution of interest...

  20. Linear polymer aqueous solutions in soft lubrication:From boundary to mixed lubrication

    Institute of Scientific and Technical Information of China (English)

    LIU; ShuHai; TAN; GuiBin; WANG; DeGuo

    2013-01-01

    In order to better understand linear polymer aqueous solutions in soft lubrication from boundary to mixed lubrication,poly(ethylene glycol) and sodium hyaluronateare used as model polymers were investigated by using UMT-2 tribometer with the ball-on-disk mode. The relationship between the master Stribeck curves of the polymer aqueous solutions and the influence factors were investigated. Experimental results indicated that soft lubrication is determined by lubricant rheological properties and surface-lubricant interactions, e.g., wetting behavior of polymer aqueous solution on tribological surfaces.

  1. Effect of Cross Linking Agent on Alkali/Surfactant/Polymer

    Institute of Scientific and Technical Information of China (English)

    ZHANG,Ke; LU,Xiang-Guo

    2008-01-01

    Alkali/surfactant/polymer (ASP) multisystem flooding technique, which has an expansive application prospect,is one of the enhancing oil recovery (EOR) methods. By adding the organic chromium to the ASP, the molecular structure of polymer was made to change, and the capability of controlling mobility coefficient of ASP was improved. The results showed that multisystem could still keep ultra-low interfacial tension between the multisystem and crude oil after addition of Cr3+. The resistance factor and residual resistance factor, the indicator which describes the capability of controlling mobility, upgraded strikingly. However its storage modulus and loss modulus,the indicator which describes viscoelasticity, increased. The results of physical simulation experiment indicated that this type of improved ASP could increase the recovery ratio by 4.3% compared to common ASP multisystem.

  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.

    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.

  3. Novel Solution for Leg Motion with 5-Link Belt Mechanism

    Science.gov (United States)

    E. Ch., Lovasz; Pop, C.; Pop, F.; Dolga, V.

    2014-11-01

    From the analysis of Theo Jansen walking mechanism and of the path curve that it describes the reduced capability for crossing over obstacles of the Jansen leg (1 DOF) is pointed out. By using a 5 link belt mechanism with 2 DOF can be adapted for generating similar Jansen mechanism path curve, where the step height of this path can be increased. For this purpose a mathematical model is conceived in order to analyse and determine the parameters for driving and control of the operation of the novel walking leg solution.

  4. 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.

  5. Growth and Structure of Zirconium Hydrous Polymers in Aqueous Solutions

    Science.gov (United States)

    Singhal; Toth; Beaucage; Lin; Peterson

    1997-10-15

    Zirconium oxychloride solutions prepared at different pH were heated at elevated temperatures for various aging periods to gain an understanding of the growth mechanism and structure of zirconium hydrous polymers. Small angle X-ray scattering (SAXS) measurements were made on these solutions. It was observed that shape of clusters at the earlier stages of growth is close to a rod rather than a sheet as suggested earlier. The scattering data indicate that a rod-shaped primary particle is formed at pH 1.2, and on an increase in the pH, the primary particles become more branched. On aging more than 1250 min at 92°C, these primary particles form large aggregates while retaining the primary particle structure. These aggregates, which are mass fractal in nature, restructure while growing in size and eventually transform into dense particles. Scattering data in this study were not enough to determine a specific kinetic growth model of the aggregates because the scattering intensity at low q constantly changes with time during the restructuring process. Copyright 1997 Academic Press. Copyright 1997Academic Press

  6. Growth and structure of zirconium hydrous polymers in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Singhal, A. [Oak Ridge National Lab., TN (United States)]|[Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry; Toth, L.M.; Lin, J.S. [Oak Ridge National Lab., TN (United States); Beaucage, G. [Univ. of Cincinnati, OH (United States). Dept. of Materials Science and Engineering; Peterson, J. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry

    1997-10-15

    Zirconium oxychloride solutions prepared at different pH were heated at elevated temperatures for various aging periods to gain an understanding of the growth mechanism and structure of zirconium hydrous polymers. Small angle X-ray scattering (SAXS) measurements were made on these solutions. It was observed that shape of clusters at the earlier stages of growth is close to a rod rather than a sheet as suggested earlier. The scattering data indicate that a rod-shaped primary particle is formed at pH 1.2, and on an increase in the pH, the primary particles become more branched. On aging more than 1,250 min at 92 C, these primary particles form large aggregates while retaining the primary particle structure. These aggregates, which are mass fractal in nature, restructure while growing in size and eventually transform into dense particles. Scattering data in this study were not enough to determine a specific kinetic growth model of the aggregates because the scattering intensity at low q constantly changes with time during the restructuring process.

  7. CO2 switchable dual responsive polymers as draw solutes for forward osmosis desalination.

    Science.gov (United States)

    Cai, Yufeng; Shen, Wenming; Wang, Rong; Krantz, William B; Fane, Anthony G; Hu, Xiao

    2013-09-28

    Low molecular weight dual responsive polymers, after purging with CO2, become polyelectrolytes with high osmolality, which can be used as draw solutes for seawater desalination. These polymers precipitate above their Lower Critical Solution Temperature (LCST) after removal of CO2 via purging with inert gas for ease of recovery and reuse.

  8. Mechanically Strong, Polymer Cross-linked Aerogels (X-Aerogels)

    Science.gov (United States)

    Leventis, Nicholas

    2006-01-01

    Aerogels comprise a class of low-density, high porous solid objects consisting of dimensionally quasi-stable self-supported three-dimensional assemblies of nanoparticles. Aerogels are pursued because of properties above and beyond those of the individual nanoparticles, including low thermal conductivity, low dielectric constant and high acoustic impedance. Possible applications include thermal and vibration insulation, dielectrics for fast electronics, and hosting of functional guests for a wide variety of optical, chemical and electronic applications. Aerogels, however, are extremely fragile materials, hence they have found only limited application in some very specialized environments, for example as Cerenkov radiation detectors in certain types of nuclear reactors, aboard spacecraft as collectors of hypervelocity particles (refer to NASA's Stardust program) and as thermal insulators on planetary vehicles on Mars (refer to Sojourner Rover in 1997 and Spirit and Opportunity in 2004). Along these lines, the X-Aerogel is a new NASA-developed strong lightweight material that has resolved the fragility problem of traditional (native) aerogels. X-Aerogels are made by applying a conformal polymer coating on the surfaces of the skeletal nanoparticles of native aerogels (see Scanning Electron Micrographs). Since the relative amounts of the polymeric crosslinker and the backbone are comparable, X-Aerogels can be viewed either as aerogels modified by the templated accumulation of polymer on the skeletal nanoparticles, or as nanoporous polymers made by remplated casting of polymer on a nanostructured framework. The most striking feature of X-Aerogels is that for a nominal 3-fold increase in density (still a ultralighweight material), the mechanical strength can be up to 300 times higher than the strength of the underlying native aerogel. Thus, X-Aerogels combine a multiple of the specific compressive strength of steel, with the the thermal conductivity of styrofoam. X

  9. Selective removal of heavy metal ions by disulfide linked polymer networks

    DEFF Research Database (Denmark)

    Ko, Dongah; Sung Lee, Joo; Patel, Hasmukh A.

    2017-01-01

    Heavy metal contaminated surface water is one of the oldest pollution problems, which is critical to ecosystems and human health. We devised disulfide linked polymer networks and employed as a sorbent for removing heavy metal ions from contaminated water. Although the polymer network material has...... a moderate surface area, it demonstrated cadmium removal efficiency equivalent to highly porous activated carbon while it showed 16 times faster sorption kinetics compared to activated carbon, owing to the high affinity of cadmium towards disulfide and thiol functionality in the polymer network. The metal...... sorption mechanism on polymer network was studied by sorption kinetics, effect of pH, and metal complexation. We observed that the metal ions―copper, cadmium, and zinc showed high binding affinity in polymer network, even in the presence of competing cations like calcium in water....

  10. Spiro-linked hyperbranched architecture in electrophosphorescent conjugated polymers for tailoring triplet energy back transfer.

    Science.gov (United States)

    Shao, Shiyang; Ma, Zhihua; Ding, Junqiao; Wang, Lixiang; Jing, Xiabin; Wang, Fosong

    2012-04-17

    A spiro-linked hyperbranched architecture has been incorporated into electrophosphorescent conjugated polymers for the first time, aiming at simultaneously tailoring the intra- and intermolecular triplet energy back transfer from the phosphorescent guest to the conjugated polymer host. Based on a prototype with this unique structure, slower decay of triplet excitons, and 5-8 fold enhancement of device efficiencies are obtained compared with the conventional blending counterpart.

  11. Structure and interaction in the polymer-dependent reentrant phase behavior of a charged nanoparticle solution.

    Science.gov (United States)

    Kumar, Sugam; Ray, D; Aswal, V K; Kohlbrecher, J

    2014-10-01

    Small-angle neutron scattering (SANS) studies have been carried out to examine the evolution of interaction and structure in a nanoparticle (silica)-polymer (polyethylene glycol) system. The nanoparticle-polymer solution interestingly shows a reentrant phase behavior where the one-phase charged stabilized nanoparticles go through a two-phase system (nanoparticle aggregation) and back to one-phase as a function of polymer concentration. Such phase behavior arises because of the nonadsorption of polymer on nanoparticles and is governed by the interplay of polymer-induced attractive depletion with repulsive nanoparticle-nanoparticle electrostatic and polymer-polymer interactions in different polymer concentration regimes. At low polymer concentrations, the electrostatic repulsion dominates over the depletion attraction. However, the increase in polymer concentration enhances the depletion attraction to give rise to the nanoparticle aggregation in the two-phase system. Further, the polymer-polymer repulsion at high polymer concentrations is believed to be responsible for the reentrance to one-phase behavior. The SANS data in polymer contrast-matched conditions have been modeled by a two-Yukawa potential accounting for both repulsive and attractive parts of total interaction potential between nanoparticles. Both of these interactions (repulsive and attractive) are found to be long range. The magnitude and the range of the depletion interaction increase with the polymer concentration leading to nanoparticle clustering. At higher polymer concentrations, the increased polymer-polymer repulsion reduces the depletion interaction leading to reentrant phase behavior. The nanoparticle clusters in the two-phase system are characterized by the surface fractal with simple cubic packing of nanoparticles within the clusters. The effect of varying ionic strength and polymer size in tuning the interaction has also been examined.

  12. Photochromic cross-link polymer for color changing and sensing surface

    Science.gov (United States)

    Fu, Richard; Shi, Jianmin; Forsythe, Eric; Srour, Merric

    2016-12-01

    Photochromic cross-link polymers were developed using patented ultraviolet (UV) photoinitiator and commercial photochromic dyes. The photochromic dyes have been characterized by measuring absorbance before and after UV activation using UV-visible (Vis) spectrometry with varying activation intensities and wavelengths. Photochromic cross-link polymers were characterized by a dynamic xenon and UV light activation and fading system. The curing processes on cloth were established and tested to obtain effective photochromic responses. Both PulseForge photonic curing and PulseForge plus heat surface curing processes had much better photochromic responses (18% to 19%, 16% to 25%, respectively) than the xenon lamp treatment (8%). The newly developed photochromic cross-link polymer showed remarkable coloration contrasts and fast and comparable coloration and fading rates. Those intelligent, controlled color changing and sensing capabilities will be used on flexible and "drapeable" surfaces, which will incorporate ultra-low power sensors, sensor indicators, and identifiers.

  13. Selective removal of heavy metal ions by disulfide linked polymer networks

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Dongah [Department of Environmental Engineering, Technical University of Denmark, Miljøvej 113, 2800 Kgs. Lyngby (Denmark); Lee, Joo Sung [Graduate School of EEWS, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141 (Korea, Republic of); Patel, Hasmukh A. [Department of Chemistry, Northwestern University, Evanston, IL 60208 (United States); Jakobsen, Mogens H. [Department of Micro and Nano technology, Technical University of Denmark, Ørsteds Plads, 345B, 2800 Kgs. Lyngby (Denmark); Hwang, Yuhoon [Department of Environmental Engineering, Seoul National University of Science and Technology, 232 Gongreung-ro, Nowon-gu, Seoul 01811 (Korea, Republic of); Yavuz, Cafer T. [Graduate School of EEWS, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141 (Korea, Republic of); Hansen, Hans Chr. Bruun [Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Thorvaldsensvej 40, 1871 Frederiksberg C (Denmark); Andersen, Henrik R., E-mail: henrik@ndersen.net [Department of Environmental Engineering, Technical University of Denmark, Miljøvej 113, 2800 Kgs. Lyngby (Denmark)

    2017-06-15

    Highlights: • Disulfide/thiol polymer networks are promising as sorbent for heavy metals. • Rapid sorption and high Langmuir affinity constant (a{sub L}) for stormwater treatment. • Selective sorption for copper, cadmium, and zinc in the presence of calcium. • Reusability likely due to structure stability of disulfide linked polymer networks. - Abstract: Heavy metal contaminated surface water is one of the oldest pollution problems, which is critical to ecosystems and human health. We devised disulfide linked polymer networks and employed as a sorbent for removing heavy metal ions from contaminated water. Although the polymer network material has a moderate surface area, it demonstrated cadmium removal efficiency equivalent to highly porous activated carbon while it showed 16 times faster sorption kinetics compared to activated carbon, owing to the high affinity of cadmium towards disulfide and thiol functionality in the polymer network. The metal sorption mechanism on polymer network was studied by sorption kinetics, effect of pH, and metal complexation. We observed that the metal ions–copper, cadmium, and zinc showed high binding affinity in polymer network, even in the presence of competing cations like calcium in water.

  14. Adhesion of endothelial cells and endothelial progenitor cells on peptide-linked polymers in shear flow.

    Science.gov (United States)

    Wang, Xin; Cooper, Stuart

    2013-05-01

    The initial adhesion of human umbilical vein endothelial cells (HUVECs), cord blood endothelial colony-forming cells (ECFCs), and human blood outgrowth endothelial cells (HBOECs) was studied under radial flow conditions. The surface of a variable shear-rate device was either coated with polymer films or covered by synthetic fibers. Spin-coating was applied to produce smooth polymer films, while fibrous scaffolds were generated by electrospinning. The polymer was composed of hexyl methacrylate, methyl methacrylate, poly(ethylene glycol) methacrylate (PEGMA), and CGRGDS peptide. The peptide was incorporated into the polymer system by coupling to an acrylate-PEG-N-hydroxysuccinimide comonomer. A shear-rate-dependent increase of the attached cells with time was observed with all cell types. The adhesion of ECs increased on RGD-linked polymer surfaces compared to polymers without adhesive peptides. The number of attached ECFCs and HBOECs are significantly higher than that of HUVECs within the entire shear-rate range and surfaces examined, especially on RGD-linked polymers at low shear rates. Their superior adhesion ability of endothelial progenitor cells under flow conditions suggests they are a promising source for in vivo seeding of vascular grafts and shows the potential to be used for self-endothelialized implants.

  15. Computer simulation of randomly cross-linked polymer networks

    CERN Document Server

    Williams, T P

    2002-01-01

    In this work, Monte Carlo and Stochastic Dynamics computer simulations of mesoscale model randomly cross-linked networks were undertaken. Task parallel implementations of the lattice Monte Carlo Bond Fluctuation model and Kremer-Grest Stochastic Dynamics bead-spring continuum model were designed and used for this purpose. Lattice and continuum precursor melt systems were prepared and then cross-linked to varying degrees. The resultant networks were used to study structural changes during deformation and relaxation dynamics. The effects of a random network topology featuring a polydisperse distribution of strand lengths and an abundance of pendant chain ends, were qualitatively compared to recent published work. A preliminary investigation into the effects of temperature on the structural and dynamical properties was also undertaken. Structural changes during isotropic swelling and uniaxial deformation, revealed a pronounced non-affine deformation dependant on the degree of cross-linking. Fractal heterogeneiti...

  16. Polymeric molecular sieve membranes via in situ cross-linking of non-porous polymer membrane templates

    Science.gov (United States)

    Qiao, Zhen-An; Chai, Song-Hai; Nelson, Kimberly; Bi, Zhonghe; Chen, Jihua; Mahurin, Shannon M.; Zhu, Xiang; Dai, Sheng

    2014-04-01

    High-performance polymeric membranes for gas separation are attractive for molecular-level separations in industrial-scale chemical, energyand environmental processes. Molecular sieving materials are widely regarded as the next-generation membranes to simultaneously achieve high permeability and selectivity. However, most polymeric molecular sieve membranes are based on a few solution-processable polymers such as polymers of intrinsic microporosity. Here we report an in situ cross-linking strategy for the preparation of polymeric molecular sieve membranes with hierarchical and tailorable porosity. These membranes demonstrate exceptional performance as molecular sieves with high gas permeabilities and selectivities for smaller gas molecules, such as carbon dioxide and oxygen, over larger molecules such as nitrogen. Hence, these membranes have potential for large-scale gas separations of commercial and environmental relevance. Moreover, this strategy could provide a possible alternative to ‘classical’ methods for the preparation of porous membranes and, in some cases, the only viable synthetic route towards certain membranes.

  17. Endothelial cell adhesion and proliferation to PEGylated polymers with covalently linked RGD peptides.

    Science.gov (United States)

    Wang, Xin; Heath, Daniel E; Cooper, Stuart L

    2012-03-01

    A nonfouling peptide grafted polymer was synthesized that can promote endothelial cell (EC) binding. The polymer was composed of hexyl methacrylate, methyl methacrylate, poly(ethylene glycol) methacrylate, and CGRGDS peptide. The peptide was incorporated into the polymer system either by a chain transfer reaction or by coupling to an acrylate-PEG-N-hydroxysuccinimide (NHS) comonomer. The introduction of PEG chains minimizes protein adsorption. Human umbilical vein ECs and endothelial colony forming cells were cultured on these surfaces in short term and long-term studies. A difference in number and morphology of ECs was observed depending on the method of peptide incorporation. Both cell types adhered better to polymer films containing NHS coupled RGD peptide after 2 h even in the presence of albumin but significant cell detachment occurred after 4 days. Polymer solutions were electrospun into fibrous scaffolds. Both nonfouling and peptide binding characteristics were retained after processing. Copyright © 2012 Wiley Periodicals, Inc.

  18. Click Cross-Linking-Improved Waterborne Polymers for Environment-Friendly Coatings and Adhesives.

    Science.gov (United States)

    Hu, Jianqing; Peng, Kaimei; Guo, Jinshan; Shan, Dingying; Kim, Gloria B; Li, Qiyao; Gerhard, Ethan; Zhu, Liang; Tu, Weiping; Lv, Weizhong; Hickner, Michael A; Yang, Jian

    2016-07-13

    Waterborne polymers, including waterborne polyurethanes (WPU), polyester dispersions (PED), and polyacrylate emulsions (PAE), are employed as environmentally friendly water-based coatings and adhesives. An efficient, fast, stable, and safe cross-linking strategy is always desirable to impart waterborne polymers with improved mechanical properties and water/solvent/thermal and abrasion resistance. For the first time, click chemistry was introduced into waterborne polymer systems as a cross-linking strategy. Click cross-linking rendered waterborne polymer films with significantly improved tensile strength, hardness, adhesion strength, and water/solvent resistance compared to traditional waterborne polymer films. For example, click cross-linked WPU (WPU-click) has dramatically improved the mechanical strength (tensile strength increased from 0.43 to 6.47 MPa, and Young's modulus increased from 3 to 40 MPa), hardness (increased from 59 to 73.1 MPa), and water resistance (water absorption percentage dropped from 200% to less than 20%); click cross-linked PED (PED-click) film also possessed more than 3 times higher tensile strength (∼28 MPa) than that of normal PED (∼8 MPa). The adhesion strength of click cross-linked PAE (PAE-click) to polypropylene (PP) was also improved (from 3 to 5.5 MPa). In addition, extra click groups can be preserved after click cross-linking for further functionalization of the waterborne polymeric coatings/adhesives. In this work, we have demonstrated that click modification could serve as a convenient and powerful approach to significantly improve the performance of a variety of traditional coatings and adhesives.

  19. Elasticity and Extensibility Determine Printability and Spinnability of Polymer Solutions

    Science.gov (United States)

    Dinic, Jelena; Jimenez, Leidy; Sharma, Vivek

    Many advanced manufacturing technologies like inkjet and 3D printing, nano-fiber spinning involve complex free-surface flows, and the formation of columnar necks that undergo spontaneous capillary-driven thinning and pinch-off. The progressive self-thinning of neck is often characterized by self-similar profiles and scaling laws that depend on the relative magnitude of capillary, inertial and viscous stresses for simple (Newtonian and inelastic) fluids. Stream-wise velocity gradients that arise within the thinning columnar neck create an extensional flow field that can orient and stretch macromolecules, contributing extra elastic stresses and extensional viscosity that change thinning and pinch-off dynamics for polymeric complex fluids. Characterizing the filament thinning and break-up kinetics in jetting, dripping and stretching liquid bridge provides invaluable insight into the interplay of elastic, viscous, capillary and inertial stresses relevant for these applications. We elucidate how polymer composition, flexibility and molecular weight determine the thinning and pinch-off kinetics in our experiments. Both effective relaxation time and transient extensional viscosity are found to be strongly concentration dependent even for dilute solutions.

  20. Understanding looping kinetics of a long polymer molecule in solution. Exact solution for delta function sink model

    Science.gov (United States)

    Ganguly, Moumita; Chakraborty, Aniruddha

    2017-10-01

    A diffusion theory for intramolecular reactions of polymer chain in dilute solution is formulated. We give a detailed analytical expression for calculation of rate of polymer looping in solution. The physical problem of looping can be modeled mathematically with the use of a Smoluchowski-like equation with a Dirac delta function sink of finite strength. The solution of this equation is expressed in terms of Laplace Transform of the Green's function for end-to-end motion of the polymer in absence of the sink. We have defined two different rate constants, the long term rate constant and the average rate constant. The average rate constant and long term rate constant varies with several parameters such as length of the polymer (N), bond length (b) and the relaxation time τR. The long term rate constant is independent of the initial probability distribution.

  1. 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.

  2. Molecular Dynamics Simulations of Polymer Networks Undergoing Sequential Cross-Linking and Scission Reactions

    DEFF Research Database (Denmark)

    Rottach, Dana R.; Curro, John G.; Budzien, Joanne;

    2007-01-01

    The effects of sequential cross-linking and scission of polymer networks formed in two states of strain are investigated using molecular dynamics simulations. Two-stage networks are studied in which a network formed in the unstrained state (stage 1) undergoes additional cross-linking in a uniaxia......The effects of sequential cross-linking and scission of polymer networks formed in two states of strain are investigated using molecular dynamics simulations. Two-stage networks are studied in which a network formed in the unstrained state (stage 1) undergoes additional cross...... good agreement with the predictions of Flory and Fricker. It was found that the fractional stress reduction upon removal of the first-stage cross-links could be accurately calculated from the slip tube model of Rubinstein and Panyukov modified to use the theoretical transfer functions of Fricker.  ...

  3. Molecular dynamics simulations of highly cross-linked polymer networks: prediction of thermal and mechanical properties

    Science.gov (United States)

    Shenogina, Natalia; Tsige, Mesfin; Mukhopadhyay, Sharmila; Patnaik, Soumya

    2012-02-01

    We use all-atom molecular dynamics (MD) simulations to predict the mechanical and thermal properties of thermosetting polymers. Atomistic simulation is a promising tool which can provide detailed structure-property relationships of densely cross-linked polymer networks. In this work we study the thermo-mechanical properties of thermosetting polymers based on amine curing agents and epoxy resins and have focused on the DGEBA/DETDA epoxy system. At first we describe the modeling approach to construction of realistic all-atom models of densely cross-linked polymer matrices. Subsequently, a series of atomistic simulations was carried out to examine the simulation cell size effect as well as the role of cross-linking density and chain length of the resin strands on thermo-mechanical properties at different temperatures. Two different methods were used to deform the polymer networks. Both static and dynamic approaches to calculating the mechanical properties were considered and the thermo-mechanical properties obtained from our simulations were found in reasonable agreement with experimental values.

  4. 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

  5. Dye linked conjugated homopolymers: using conjugated polymer electroluminescence to optically pump porphyrin-dye emission

    DEFF Research Database (Denmark)

    Nielsen, K.T.; Spanggaard, H.; Krebs, Frederik C

    2004-01-01

    . Electroluminescent devices of the homopolymer itself and of the zinc-porphyrin containing polymer were prepared and the nature of the electroluminescence was characterized. The homopolymer segments were found to optically pump the emission of the zinc-porphyrin dye moities. The homopolymer exhibits blue......Zinc-porphyrin dye molecules were incorporated into the backbone of a conjugated polymer material by a method, which allowed for the incorporation of only one zinc-porphyrin dye molecule into the backbone of each conjugated polymer molecule. The electronic properties of the homopolymer were......-green emission and the zinc-porphyrin linked homopolymers emit near-infrared/infrared light. This was demonstrated to be due to electroluminescence pumping of the zinc-porphyrin moieties that were covalently linked to homopolymer material. When only one zinc-porphyrin dye was incorporated into the backbone...

  6. Variation of persistence length with concentration in a hydrogen bonding polymer solution

    Science.gov (United States)

    Sukumaran, S.; Beaucage, G.

    2000-03-01

    Miscibility of some polymers in water is usually attributed to the ability of the polymer to hydrogen bond with water. Hydrogen bonding contributes a strong interaction component to the free energy that enhances mixing between the polymer and water. It is widely known that certain conformations of the polymer have significantly higher dipole moment and consequently higher affinity for water. If the solvent alters the bond rotation energetics of the polymer it is natural to expect the average local structure of the chain to be affected leading to a change in the persistence length. Small angle neutron scattering experiments were performed on aqueous (D2O) solutions of a polymer (PEO or PVME) at different concentrations to investigate the microscopic structure of these solutions. The persistence length was strongly dependent on concentration. A simple physical explanation for this phenomenon will be provided. Possible ramifications of such a phenomenon in understanding phase behavior will be indicated.

  7. Preparation of CdTe nanocrystal-polymer composite microspheres in aqueous solution by dispersing method

    Institute of Scientific and Technical Information of China (English)

    LI Minjie; WANG Chunlei; HAN Kun; YANG Bai

    2005-01-01

    Highly fluorescent CdTe nanocrystals were synthesized in aqueous solution, and then processible CdTe nanocrystal-polymer composites were fabricated by coating the aqueous nanocrystals with copolymers of styrene and octadecyl-p-vinyl-benzyldimethylammonium chloride (SOV- DAC) directly. A dichloromethane solution of CdTe nano- crystal-polymer composites was dispersed in the aqueous solution of poly (vinyl alcohol) (PVA) generating highly fluorescent microspheres. Experimental parameters such as the concentration of nanocrystal-polymer composites, the concentration of PVA, and stirring speed which had important effect on the preparation of the microspheres were investigated in detail with fluorescent microscope characterization.

  8. Coil size oscillatory packing in polymer solutions near a surface

    NARCIS (Netherlands)

    Gucht, van der J.; Besseling, N.A.M.; Male, van J.; Cohen Stuart, M.A.

    2000-01-01

    The theory developed by Scheutjens and Fleer to describe polymer adsorption and depletion is used to calculate the density profile of nonadsorbing polymers near a surface. The theory predicts damped oscillations in the segment density profile with a wavelength of about the coil size. As a consequenc

  9. 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.

  10. Polymers and Cross-Linking: A CORE Experiment to Help Students Think on the Submicroscopic Level

    Science.gov (United States)

    Bruce, Mitchell R. M.; Bruce, Alice E.; Avargil, Shirly; Amar, Francois G.; Wemyss, Thomas M.; Flood, Virginia J.

    2016-01-01

    The Polymers and Cross-Linking experiment is presented via a new three phase learning cycle: CORE (Chemical Observations, Representations, Experimentation), which is designed to model productive chemical inquiry and to promote a deeper understanding about the chemistry operating at the submicroscopic level. The experiment is built on two familiar…

  11. Cross-Linked Nanoporous Materials from Reactive and Multifunctional Block Polymers

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-10-10

    Polylactide-b-poly(styrene-co-2-hydroxyethylmethacrylate) (PLA-b-P(S-co-HEMA)) and polylactide-b-poly(styrene-co-2-hydroxyethylacrylate) (PLA-b-P(S-co-HEA)) were synthesized by combination of ring-opening polymerization and reversible addition-fragmentation chain transfer polymerization. {sup 1}H nuclear magnetic resonance spectroscopy and size exclusion chromatography data indicated that the polymerizations were controlled and that hydroxyl groups were successfully incorporated into the block polymers. The polymers were reacted with 4,4{prime}-methylenebis(phenyl isocyanate) (MDI) to form the corresponding cross-linked materials. The materials were annealed at 150 C to complete the coupling reaction. Robust nanoporous materials were obtained from the cross-linked polymers by treatment with aqueous base to hydrolyze the PLA phase. Small-angle X-ray scattering study combined with scanning electron microscopy showed that MDI-cross-linked PLA-b-P(S-co-HEMA)/PLA-b-P(S-co-HEA) can adopt lamellar, hexagonally perforated lamellar, and hexagonally packed cylindrical morphologies after annealing. In particular, the HPL morphology was found to evolve from lamellae due to increase in volume fraction of PS phase as MDI reacted with hydroxyl groups. The reaction also kinetically trapped the morphology by cross-linking. Bicontinuous morphologies were also observed when dibutyltin dilaurate was added to accelerate reaction between the polymer and MDI.

  12. EFFECT OF ANIONIC SURFACTANT UPON THE VISCOSITY OF POLYMER GUAR GUM SOLUTIONS

    Institute of Scientific and Technical Information of China (English)

    Xiao-ming Chen; Hai-yang Yang; Xian You; Ping-ping Zhu; Ping-sheng Hea

    2006-01-01

    The reduced viscosity of polymer guar gum solutions containing a certain concentration of sodium dodecyl benzene sulfonate (SDBS) was measured. It has been found that the Huggins coefficient kH of polymer solutions is verysensitive to the concentration of the surfactant, cSDBS, in solutions. If cSDBS is lower than CMC, the critical micelle concentration of SDBS, kH increases rapidly with cSDBS. On the other hand, if cSDBS is larger than CMC, kH decreases rapidly with cSDBS. Comparatively, the intrinsic viscosity of polymer solution does not show a notable change with cSDBS. The experimental results indicate that the interchain association of polymer guar gum in solution is greatly associated with SDBS interacted with polymer chains through hydrogen bonds. However, the effect of SDBS upon the intrachain association of polymer guar gum solution is negligible, presumably due to the fact that guar gum is a slightly stiffened random-coil chain polymer.

  13. Comparative studies of photochemical cross-linking methods for stabilizing the bulk hetero-junction morphology in polymer solar cells

    DEFF Research Database (Denmark)

    Carlé, Jon Eggert; Andreasen, Birgitta; Tromholt, Thomas;

    2012-01-01

    -light illumination to give solvent resistant films and reduced phase separation and growth of PCBM crystallites in polymer:PCBM films. The stability of solar cells based on the cross-linked polymers was tested under various conditions. This study showed that cross-linking can improve morphological stability...

  14. The direct link model for polymer rings using topological field theory and the second topological moment in dense systems

    Energy Technology Data Exchange (ETDEWEB)

    Otto, Matthias [Institut fuer Theoretische Physik, Universitaet Goettingen, Goettingen (Germany)

    2001-03-30

    Polymer rings in solution are either permanently entangled or are not. Permanent topological restrictions give rise to additional entropic interactions apart from the ones arising due to mere chain flexibility or excluded volume. Conversely, entangled polymer rings systems may be formed by closing randomly entangled flexible linear chains. The dependence of linking numbers between randomly entangled rings on the chain length, more specifically the second topological moment , i.e. the average squared linking number, may be determined. In this paper, an approach recently discussed in mathematical physics and called Abelian BF theory, is presented which allows one to express the linking constraint in its simplest form, the Gauss integral, in terms of two gauge fields. The model of Brereton and Shah for a single ring entangled with many other surrounding rings is rederived. The latter model is finally used to calculate the second topological moment, in agreement with a recent result by Ferrari, Kleinert, and Lazzizzera obtained using n-component {phi}{sup 4} theory for the limit n{yields}0. (author)

  15. 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.

    2011-01-01

    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 th

  16. 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...

  17. Capillary electrophoresis investigation on equilibrium between polymer-related and surfactant-related species in aqueous polymer-surfactant solutions.

    Science.gov (United States)

    Wu, Yefan; Chen, Miaomiao; Fang, Yun; Zhu, Meng

    2017-03-17

    It was inferred from aqueous solution behavior of nonionic polymers and anionic surfactants that the formation of charged polymer-bound surfactant micelle above critical aggregation concentration (cac) and the formation of free surfactant micelle beyond polymer saturation point (psp), but there was still a lack of direct experimental evidence for the considered equilibrium chemical species. Three modes of capillary electrophoresis are applied in this paper to study the complexation between nonionic polymers, polyvinylpyrrolidone (PVP) or polyethylene glycol (PEG), and sodium dodecylbenzenesulfonate (SDBS) by successfully distinguishing the imaginary charged polymer-bound SDBS micelle from nonionic polymer and SDBS molecule. Perhaps even more important, it is the action of SDBS as both a main surfactant and a UV probe that makes the free surfactant micelle emerged in electropherogram beyond psp, and thus makes it possible for the first time to provide the equilibrium relationship of the polymer-related and the surfactant-related species in the concentration regions divided into by cac and psp. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Biomolecule-recognition gating membrane using biomolecular cross-linking and polymer phase transition.

    Science.gov (United States)

    Kuroki, Hidenori; Ito, Taichi; Ohashi, Hidenori; Tamaki, Takanori; Yamaguchi, Takeo

    2011-12-15

    We present for the first time a biomolecule-recognition gating system that responds to small signals of biomolecules by the cooperation of biorecognition cross-linking and polymer phase transition in nanosized pores. The biomolecule-recognition gating membrane immobilizes the stimuli-responsive polymer, including the biomolecule-recognition receptor, onto the pore surface of a porous membrane. The pore state (open/closed) of this gating membrane depends on the formation of specific biorecognition cross-linking in the pores: a specific biomolecule having multibinding sites can be recognized by several receptors and acts as the cross-linker of the grafted polymer, whereas a nonspecific molecule cannot. The pore state can be distinguished by a volume phase transition of the grafted polymer. In the present study, the principle of the proposed system is demonstrated using poly(N-isopropylacrylamide) as the stimuli-responsive polymer and avidin-biotin as a multibindable biomolecule-specific receptor. As a result of the selective response to the specific biomolecule, a clear permeability change of an order of magnitude was achieved. The principle is versatile and can be applied to many combinations of multibindable analyte-specific receptors, including antibody-antigen and lectin-sugar analogues. The new gating system can find wide application in the bioanalytical field and aid the design of novel biodevices.

  19. 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.

  20. POLYMER COLLOIDS FORMED BY POLYELECTROLYTE COMPLEXATION OF VINYL POLYMERS AND POLYSACCHARIDES IN AQUEOUS SOLUTION

    Institute of Scientific and Technical Information of China (English)

    Hui-dan Liu; Takahiro Sato

    2013-01-01

    The polyelectrolyte complex formed from the polyanion and polycation was studied by turbidimetry,static and electrophoretic light scattering,and elementary analysis.Sodium salts of polyacrylate (PA) and heparin (Hep) were chosen as the polyanion,and hydrochloric salts of poly(vinyl amine) (PVA) and chitosan (Chts) as the polycation.Although these vinyl polymers and polysaccharides have remarkably different backbone chemical structures and linear charge densities,all the four combinations PA-PVA,PA-Chts,Hep-PVA,and Hep-Chts provide almost stoichiometric polyelectrolyte complexes which are slightly charged owing to the adsorption of the excess polyelectrolyte component onto the neutral complex.The charges stabilize the complex colloids in aqueous solution of a non-stoichiometric mixture,and the aggregation number of the complex colloids increases with approaching to the stoichiometric mixing ratio.The mixing ratio dependence of the aggregation number for the four complexes is explained by the model proposed in the previous study.

  1. Effect of added polymer in free jets of a dilute polymer solution

    Science.gov (United States)

    Renoult, Marie-Charlotte; Charpentier, Jean-Baptiste; Crumeyrolle, Olivier; Mutabazi, Innocent

    2016-11-01

    The instability of a free viscoelastic jet is experimentally investigated by extruding an aqueous solution containing five parts per million of Poly(ethylene oxide) into air from a sixty micrometers orifice at relative low speeds. A method of image analysis was developed to quantify the effect of the added polymer on the morphology and the stability of the jet breakup. Three main representations were considered: the area versus perimeter relation for all liquid objects detected on the images, i.e. jets and jet fragments, the equivalent diameter distribution of jet fragments and the standard deviation curve of jets profiles. The former two provide information on the morphology of jet fragments: distinction of two classes, products and residues, and existence of coalescence. The latter gives information on the jet breakup stability: measurement of the growth rate and initial amplitude of the jet instability and detection of beads-on-a-string structures in the jet interface deformation. Experimental results will be presented and compared to theory.

  2. Elastic Energy Transfer in Turbulence of Dilute Polymer Solution

    Science.gov (United States)

    Xi, Heng-Dong; Bodenschatz, Eberhard; Xu, Haitao

    2012-11-01

    We present an experimental study of the energy transfer in the bulk of a turbulent flow with small amount long-chain polymer additives. By varying the Reynolds numbers Rλ, Wissenberg number Wi and polymer concentration φ. We test quantitively the elastic theory proposed by de Gennes and Tabor (Europhys. Lett., 1986; Physica A, 1986). The rate of energy transfer by polymer elasticity as inferred from the theory is consistent with that measured from the second order Eulerian structure functions. The unknown parameter n in the theory, which represents the flow topology of the stretching field, is found to be nearly 1. Based on energy transfer rate balance, We propose an elastic length scale, rɛ, which describes the effect of polymer elasticity on turbulence energy cascade and captures the scale dependence of the elastic energy transfer rate. We are grateful to the Max Planck Society, the Alexander von Humboldt Foundation and the Deutsche Forschungsgemeinschaft for their support.

  3. Core Cross-linked Star Polymers for Temperature/pH Controlled Delivery of 5-Fluorouracil

    Directory of Open Access Journals (Sweden)

    Elizabeth Sánchez-Bustos

    2016-01-01

    Full Text Available RAFT polymerization with cross-linking was used to prepare core cross-linked star polymers bearing temperature sensitive arms. The arms consisted of a diblock copolymer containing N-isopropylacrylamide (NIPAAm and 4-methacryloyloxy benzoic acid (4MBA in the temperature sensitive block and poly(hexyl acrylate forming the second hydrophobic block, while ethyleneglycol dimethacrylate was used to form the core. The acid comonomer provides pH sensitivity to the arms and also increases the transition temperature of polyNIPAAm to values in the range of 40 to 46°C. Light scattering and atomic force microscopy studies suggest that loose core star polymers were obtained. The star polymers were loaded with 5-fluorouracil (5-FU, an anticancer agent, in values of up to 30 w/w%. In vitro release experiments were performed at different temperatures and pH values, as well as with heating and cooling temperature cycles. Faster drug release was obtained at 42°C or pH 6, compared to normal physiological conditions (37°C, pH 7.4. The drug carriers prepared acted as nanopumps changing the release kinetics of 5-FU when temperatures cycles were applied, in contrast with release rates at a constant temperature. The prepared core cross-linked star polymers represent advanced drug delivery vehicles optimized for 5-FU with potential application in cancer treatment.

  4. Mathematical modeling of methoxyanabasine C11H16N2O polymer solution ultrafiltration

    Science.gov (United States)

    Satayev, Marat; Shakirov, Birzhan; Mutaliyeva, Botagoz; Satayeva, Lazzat; Altynbekov, Rustem; Baiysbay, Omirbek; Alibekov, Ravshanbek

    2012-06-01

    This work covers the mathematical modeling of ultrafiltration with immobile membranes for physiologically-active of methoxyanabasine C11H16N2O polymer solution. Methoxyanabasine is used as low toxic antineoplastic drug. On the basis of theoretical and experimental analysis of mass transfer and hydrodynamics, it is offered the mathematical model of permeability of membranes at an ultrafiltration of polymer solutions. Further the formulas for determination of factor of concentration polarization and ultrafiltration selectivity are calculated.

  5. Exact Solution of the Cluster Size Distribution for Multi-polymer Coagulation Process

    Institute of Scientific and Technical Information of China (English)

    KE Jian-Hong; LIN Zhen-Quan; WANG Xiang-Hong

    2003-01-01

    We propose a simple irreversible multi-polymer coagulation model in which m polymers consist of multiple components bond spontaneously to form a larger cluster. We solve the generalized Smoluchowski rate equation with constant reaction rates to obtain the exact solution of the cluster size distribution. The results indicate that the evolution behaviour of the system depends crucially on the polymer number m of the coagulation reaction. The cluster concentrations decay as t~m/(m~l) ; anc; tne typical size S(t) of the m-polymer coagulation system grows as t /'m~1'. On the other hand, the cluster size distribution may approach unusual scaling form in some cases.

  6. Cross-Linked Liquid Crystalline Systems From Rigid Polymer Networks to Elastomers

    CERN Document Server

    Broer, Dirk

    2011-01-01

    With rapidly expanding interest in liquid crystalline polymers and elastomers among the liquid crystal community, researchers are currently exploring the wide range of possible application areas for these unique materials, including optical elements on displays, tunable lasers, strain gauges, micro-structures, and artificial muscles. Written by respected scientists from academia and industry around the world, who are not only active in the field but also well-known in more traditional areas of research, "Cross-Linked Liquid Crystalline Systems: From Rigid Polymer Networks to Elastomers&qu

  7. Graft copolymerization onto polybutadiene: Cross-linking and thermal degradation of vinyl polymers and copolymers

    Science.gov (United States)

    Jiang, Dayue (David)

    This work consists of three parts. In Part I, the graft copolymerization of methyl methacrylate, methyl acrylate, methacylic acid and acrylic acid onto polybutadiene and its copolymers by benzoyl peroxide, BPO, or 2, 2'azobis(2-methylpropionitrile), AIBN, initiation were explored. The results show that these monomers can be grafted onto butadiene region of butadiene-containing polymers. The extent of both graft copolymerization and homopolymerization are dependent on the time and temperature of the reaction and the concentration of all of the reactants. One must specify the monomer, initiator and solvent for the efficient graft copolymerization. The methyl methacrylate adds directly to the radical sites which are formed on the backbone by the interaction of the polymer and the primary radical form the initiator, while for the other three monomers, the graft copolymerization occurs by addition of macro-radical to the double bonds. In Part II, the cross-linking of polybutadiene, butadiene-styrene copolymers, and polystyrene by irradiation, thermal and chemical processes, and Friedel-Crafts chemistry and the effect of cross-linking on the thermal stability were investigated. The proof of cross-linking of the polymer comes from the insolubility of the product after the cross-linking reaction and is characterized by gel content and swelling ratio. The results show that the thermal stability of the polymer can be improved by cross-linking. In Part III, the thermal degradation of three vinyl polymers, poly(vinylsulfonic acid) and its sodium salt and poly(vinylphosphonic acid) were studied by combination technique: TGA/FTIR. The results show that TGA/FTIR combined with analysis of residues provides an excellent opportunity to understand the degradation pathway of the compounds. The observation of foaming indicates that the char which is formed contains carbon as well as the inorganic salts which have been observed. The carbon is in a partially graphitized form. The salts

  8. Application of the van der Waals equation of state to polymers .4. Correlation and prediction of lower critical solution temperatures for polymer solutions

    DEFF Research Database (Denmark)

    Goncalves, Ana Saraiva; Kontogeorgis, Georgios; Harismiadis, Vassilis I.

    1996-01-01

    The van der Waals equation of state is used for the correlation and the prediction of the lower critical solution behavior or mixtures including a solvent and a polymer. The equation of state parameters for the polymer are estimated from experimental volumetric data at low pressures. The equation...... of state parameters for the solvent are estimated via the classical Soave method, i.e. using the critical properties and a generalized equation for the energy parameter. When extended to mixtures, the van der Waals one-fluid mixing rules along with the Berthelot combining rule for the molecular cross...... energy parameter are used. The arithmetic mean combining rule is used for the cross co-volume parameter. The deviations from the Berthelot combining rule are taken into account via a simple expression which has been previously obtained from vapor-liquid equilibrium data of athermal polymer solutions...

  9. Study on the sound absorption mechanism in gradient water-soluble polymer solution

    Institute of Scientific and Technical Information of China (English)

    WANG Yuansheng; YANG Xue; ZHU Jinhua; YAO Shuren

    2006-01-01

    Attention was paid to the study on the sound absorption mechanism of watersoluble polymer during dissolving. A specially designed water-soluble polymer coating was synthesized in our lab. The sound attenuation property was measured in sound tube. The results showed that the sound attenuation of the gradient polymer solution was larger than that of the uniform. Depending on the experimental result and the theory of sound wave propagation in layered medium, a mechanism of gradient water-soluble polymer solution was developed. This mechanism can be described as follows: a water-soluble polymer coating formed a concentration gradient layer when it was dissolved in water. This gradient layer led to multiple reflection and absorption of sound. Finally the sound energy was transferred into heat.

  10. 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...... in a self-consistent approach, it is demonstrated that the corona can be regarded as a quasi-two-dimensional polymer solution, with a concentration dependence analogous to that of an ordinary polymer solution. Scattering due to the corona profile and density fluctuation correlations are separated...

  11. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Budkov, Yu. A., E-mail: urabudkov@rambler.ru [G. A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences, Laboratory of NMR Spectroscopy and Numerical Investigations of Liquids, Ivanovo (Russian Federation); Department of Applied Mathematics, National Research University Higher School of Economics, Moscow (Russian Federation); Kolesnikov, A. L. [Institut für Nichtklassische Chemie e.V., Universitat Leipzig, Leipzig (Germany); Kiselev, M. G. [G. A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences, Laboratory of NMR Spectroscopy and Numerical Investigations of Liquids, Ivanovo (Russian Federation)

    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.

  13. Light-harvesting cross-linked polymers for efficient heterogeneous photocatalysis.

    Science.gov (United States)

    Wang, Cheng; Xie, Zhigang; deKrafft, Kathryn E; Lin, Wenbin

    2012-04-01

    Nonporous, phosphorescent cross-linked polymers (Ru-CP and Ir-CP) were synthesized via Pd-catalyzed Sonogashira cross-coupling reactions between tetra(p-ethynylphenyl)methane and dibrominated Ru(bpy)(3)(2+) or Ir(ppy)(2)(bpy)(+), respectively. The resultant particulate cross-linked polymer (CP) materials have very high catalyst loadings (76.3 wt % for Ru-CP and 71.6 wt % for Ir-CP), and are nonporous with negligibly small surface areas (2.9 m(2)/g for Ru-CP and 2.7 m(2)/g for Ir-CP). Despite their nonporous nature, the insoluble CP materials serve as highly active and recyclable heterogeneous photocatalysts for a range of organic transformations such as aza-Henry reaction, aerobic amine coupling, and dehalogenation of benzyl bromoacetate. An efficient light-harvesting mechanism, which involves collection of photons by exciting the (3)MLCT states of the phosphors and migration of the excited states to the particle surface, is proposed to account for the very high catalytic activities of these nonporous CPs. Steady-state and time-resolved emission data, as well as the reduced catalytic activity of Os(bpy)(3)(2+)-doped Ru-CPs supports efficient excited state migration for the CP frameworks. This work uncovers a new strategy in designing highly efficient photocatalysts based on light-harvesting cross-linked polymers.

  14. Emerging synthetic strategies for core cross-linked star (CCS) polymers and applications as interfacial stabilizers: bridging linear polymers and nanoparticles.

    Science.gov (United States)

    Chen, Qijing; Cao, Xueteng; Xu, Yuanyuan; An, Zesheng

    2013-10-01

    Core cross-linked star (CCS) polymers become increasingly important in polymer science and are evaluated in many value-added applications. However, limitations exist to varied degrees for different synthetic methods. It is clear that improvement in synthetic efficiency is fundamental in driving this field moving even further. Here, the most recent advances are highlighted in synthetic strategies, including cross-linking with cross-linkers of low solubility, polymerization-induced self-assembly in aqueous-based heterogeneous media, and cross-linking via dynamic covalent bonds. The understanding of CCS polymers is also further refined to advocate their role as an intermediate between linear polymers and polymeric nanoparticles, and their use as interfacial stabilizers is rationalized within this context.

  15. 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

    and polymer melts. We compare the nonlinear extensional rheology of a series of polystyrene solutions with wide concentration range between 10% and 100% (melt) in order to determine the key missing physics that can account for dilution effects. All the solutions studied have the same number of entanglements...

  16. Large velocity fluctuations in small-Reynolds-number pipe flow of polymer solutions

    NARCIS (Netherlands)

    Bonn, D.; Ingremeau, F.; Amarouchene, Y.; Kellay, H.

    2011-01-01

    The flow of polymer solutions is examined in a flow geometry where a jet is used to inject the viscoelastic solution into a cylindrical tube. We show that this geometry allows for the generation of a "turbulentlike" flow at very low Reynolds numbers with a fluctuation level which can be as high as 3

  17. 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...

  18. Shape-memory behavior of cross-linked semi-crystalline polymers and their blends

    Directory of Open Access Journals (Sweden)

    I. Kolesov

    2015-03-01

    Full Text Available The present study deals with thermally induced one-way and invertible two-way shape-memory effect (SME in covalent networks on the basis of crystallizable (copolymers and their blends and is an attempt to generalize the results of own investigation received by the authors in the last ten years. The main focus of work clearly lies on research of covalently crosslinked binary and ternary blends having two and three crystalline phases with different thermal stability, respectively. The existence of two or three crystalline phases possessing different melting and crystallization temperatures in heterogeneous polymer networks can lead to triple-shape or even quadruple-shape behavior of such networks. However, the performed investigations point to crucial effect of phase morphology of crosslinked polymer blends on multiplicity of their shapememory behavior beside the influence of blend content, crystallinity and cross-link density of blend phases as well as of processing conditions. For instance, triple-shape memory behavior in binary blends can be realized only if the continuous phase has a lower melting temperature than the dispersed phase. Cross-linked polymer blends are a facile alternative to expensive and complex synthesis of interpenetrating or block-copolymer networks used for shape memory polymers. In addition to findings of experimental investigation of SME in crystallizable covalent polymer networks, the results of modeling their shape-memory behavior on the basis of self-developed physically reasonable model have been briefly described and discussed. Thereby, good accordance between results of theory and experiment was achieved with physically justified fitting parameters.

  19. Solution electrospinning of particle-polymer composite fibres

    DEFF Research Database (Denmark)

    Christiansen, Lasse; Fojan, Peter

    2016-01-01

    Electrospinning is a fast, simple way to produce nano/microfibers, resulting in porous mats with a high surface to volume ratio. Another material with high surface to volume ratio is aerogel. A drawback of aerogels is its inherent mechanical weakness. To counteract this, aerogels can be embedded......-supporting abilities of these fibres are discussed. It is concluded that selfsupporting polymer/aerogel composites can be made by electrospinning....

  20. Elastic turbulence in a shell model of polymer solution

    CERN Document Server

    Ray, Samriddhi Sankar

    2016-01-01

    We show that, at low inertia and large elasticity, shell models of viscoelastic fluids develop a chaotic behaviour with properties similar to those of elastic turbulence. The low dimensionality of shell models allows us to explore a wide range both in polymer concentration and in Weissenberg number. Our results demonstrate that the physical mechanisms at the origin of elastic turbulence do not rely on the boundary conditions or on the geometry of the mean flow.

  1. 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.)

  2. Preparation and characterization of cross-linked β-cyclodextrin polymer/Fe3O4 composite nanoparticles with core-shell structures

    Institute of Scientific and Technical Information of China (English)

    Rui Xue Li; Shu Mei Liu; Jian Qing Zhao; Hideyuki Otsuka; Atsushi Takahara

    2011-01-01

    Cross-linked β-cyclodextrin polymer/Fe3O4 composite nanoparticles with core-shell structures were prepared via cross linking reaction on the surface of carboxymethyl β-cyclodextrin (CM-β-CD) modified Fe3O4 nanoparticles in β-cyclodextrin alkaline solution by using epichlorohydrin as crosslinking agent. The morphology, structure and magnetic properties of the prepared composite nanoparticles were investigated by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectrometry, X-ray diffraction (XRD) measurement, thermogravimetric analysis (TGA) and Vibrating sample magnetometry (VSM), respectively.

  3. Ultrafast photogeneration of charged polarons on conjugated polymer chains in dilute solution

    Science.gov (United States)

    Miranda, Paulo B.; Moses, Daniel; Heeger, Alan J.

    2004-08-01

    Ultrafast photoinduced absorption by infrared-active vibrational modes is used to study the photogeneration of polarons on semiconducting polymer chains in dilute solutions and in solid films of a soluble derivative of poly(para-phenylene vinylene). In dilute solutions, polaron pairs are photogenerated on the conjugated polymer within less than 250fs with quantum efficiencies ϕch˜3% , about one-third of that for solid films of the same polymer. The excitation spectra of ϕch for both solutions and films show that ϕch is weakly dependent on photon energy between 2.2eV (the onset of absorption) and 4.7eV . The recombination dynamics of polarons is very fast and highly dependent on the excitation density for polymer films, but it is significantly slower and less sensitive to pump intensity for the semiconducting polymer in dilute solution. We conclude that the positive and negative polarons on a single chain in solution are typically separated by hundreds of monomer repeat units and that their one-dimensional diffusion along the chain is inhibited by the intervening excitons. This, together with the suppression of interchain recombination, explains the surprisingly slower polaron recombination in isolated chains.

  4. Modeling HVDC links in composite reliability evaluation: issues and solutions

    Energy Technology Data Exchange (ETDEWEB)

    Reis, Lineu B. de [Sao Paulo Univ., SP (Brazil). Escola Politecnica; Ramos, Dorel S. [Centrais Eletricas de Sao Paulo, SP (Brazil); Morozowski Filho, Marciano [Santa Catarina Univ., Florianopolis, SC (Brazil)

    1992-12-31

    This paper deals with theoretical and practical aspects of HVDC link modeling for composite (generation and transmission) system reliability evaluation purposes. The conceptual framework used in the analysis, as well as the practical aspects, are illustrated through an application example. Initially, two distinct HVDC link operation models are described: synchronous and asynchronous. An analysis of the most significant internal failure modes and their effects on HVDC link transmission capability is presented and a reliability model is proposed. Finally, a historical performance data of the Itaipu HVDC system is shown. 6 refs., 5 figs., 8 tabs.

  5. Cross-linked supramolecular polymer metallogels constructed via a self-sorting strategy and their multiple stimulus-response behaviors.

    Science.gov (United States)

    Wang, Xu-Qing; Wang, Wei; Yin, Guang-Qiang; Wang, Yu-Xuan; Zhang, Chang-Wei; Shi, Jia-Meng; Yu, Yihua; Yang, Hai-Bo

    2015-12-01

    Novel cross-linked supramolecular polymer metallogels were successfully constructed from four components via a self-sorting strategy, and feature interesting multiple stimulus-response behaviors under various external stimuli, including halide, base, and competitive guests.

  6. 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.

  7. A modified coaxial electrospinning for preparing fibers from a high concentration polymer solution

    Directory of Open Access Journals (Sweden)

    2011-08-01

    Full Text Available A new process technology modified from conventional coaxial electrospinning process has been developed to prepare polymer fibers from a high concentration solution. This process involves a pure solvent concentrically surrounding polymer fluid in the spinneret. The concentric spinneret was constructed simply by inserting a metal needle through a high elastic silica gel tube. Two syringe pumps were used to drive the core polymer solution and the sheath solvent. Using polyvinylpyrrolidone (PVP as the polymer model, which normally has an electrospinnable concentration of 10% w/v in ethanol, it was possible to electrospin 35% w/v of PVP in the same solvent, when pure N, N-dimethylacetamide (DMAc was used as sheath fluid. The resultant fibers have a smooth surface morphology and good structural uniformity. The diameter of the fibers was 2.0±0.25 µm when the DMAc-to-polymer-solution flow rate ratio was set as 0.1. The process technology reported here opens a new window to tune the polymer fibers obtained by the electrospinning, and is useful for improving productivity of the electrospinning process.

  8. Interactions between ring polymers in dilute solution studied by Monte Carlo simulation

    Science.gov (United States)

    Suzuki, Jiro; Takano, Atsushi; Matsushita, Yushu

    2015-01-01

    The second virial coefficient, A2, for trivial-ring polymers in dilute condition was estimated from a Metropolis Monte Carlo (MC) simulation, and the temperature dependence of A2 has been discussed with their Flory's scaling exponent, ν, in Rg ∝ Nν, where Rg is radius of gyration of a polymer molecule. A limited but not too small number of polymer molecules were employed in the simulation, and the A2 values at various temperatures were calculated from the molecular density fluctuation in the solution. In the simulation, the topology of ring polymers was kept, since chain crossing was prohibited. The excluded volume effects can be screened by the attractive force between segments, which depends on the temperature, Tα, defined in the Metropolis MC method. Linear and trivial-ring polymers have the ν value of 1/2 at Tα = 10.605 and 10.504. At Tα = 10.504, the excluded volume effects are screened by the attractive force generated between segments in a ring polymer, but the A2 value for ring polymers is positive. Thus, the temperature at A2 = 0 for a ring polymer is lower than that at ν = 1/2, and this fact can be explained with the following two reasons. (a) Rg value for a ring polymer is much smaller than that for a linear polymer at the same temperature and molecular weight, where interpenetration of a ring polymer chain into neighboring chains is apparently less than a linear chain. (b) The conformation of trivial rings can be statistically described as a closed random walk at ν = 1/2, but their topologies are kept, being produced topological constraints, which strongly relate not only to the long-distance interaction between segments in a molecule but also the inter-molecular interaction.

  9. Langevin dynamcis simulations of driven polymer translocation into a cross-linked gel.

    Science.gov (United States)

    Sean, David; Slater, Gary W

    2017-03-01

    We investigate the dynamics of driving a polyelectrolyte such as DNA through a nanopore and into a cross-linked gel. Placing the gel on the trans-side of the nanopore can increase the translocation time while not negatively affecting the capture rates. Thus, this setup combines the mechanics of gel electrophoresis with nanopore translocation. However, contrary to typical gel electrophoresis scenarios, the effect of the field is localized in the immediate vicinity of the nanopore and becomes negligible inside the gel matrix. Thus, we investigate the process by which a semiflexible polymer can be pushed into a gel matrix via a localized field and we describe how the dynamics of gel penetration depends upon the field intensity, polymer stiffness, and gel pore size. Our simulation results show that a semiflexible polymer enters the gel region with two distinct mechanisms depending upon the ratio between the bending length scale and the gel pore size. In both regimes, the gel fibers cause a net increase in the mean translocation time. Interestingly, the translocation rate is found to be constant (a potentially useful feature for many applications) during the predominant part of the translocation process when the polymer is stiff over a length scale comparable to the gel pore size.

  10. 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.

  11. Influence of Salts on Electrospinning of Aqueous and Nonaqueous Polymer Solutions

    Directory of Open Access Journals (Sweden)

    Fatma Yalcinkaya

    2015-01-01

    Full Text Available A roller electrospinning system was used to produce nanofibres by using different solution systems. Although the process of electrospinning has been known for over half a century, knowledge about spinning behaviour is still lacking. In this work, we investigated the effects of salt for two solution systems on spinning performance, fibre diameter, and web structure. Polyurethane (PU and polyethylene oxide (PEO were used as polymer, and tetraethylammonium bromide and lithium chloride were used as salt. Both polymer and salt concentrations had a noteworthy influence on the spinning performance, morphology, and diameter of the nanofibres. Results indicated that adding salt increased the spinnability of PU. Salt created complex bonding with dimethylformamide solvent and PU polymer. Salt added to PEO solution decreased the spinning performance of fibres while creating thin nanofibres, as explained by the leaky dielectric model.

  12. Comparison of viscous fingering patterns in polymer and newtonian solutions

    Science.gov (United States)

    Kawaguchi, Masami; Makino, Kyoko; Kato, Tadaya

    1997-02-01

    Viscous fingering patterns of aqueous glycerol and hydroxypropyl methyl cellulose (HPMC) solutions pushed by air in the Hele-Shaw cell were observed as a function of isopropyl alcohol. An increase in isopropyl alcohol led to a decrease in surface tension as well as an increase in viscosity of the respective solutions. For the glycerol solutions, namely Newtonian fluids, only the tip splitting pattern was observed, where the fingers were indeed narrower and the number of the fingers increased with increasing isopropyl alcohol content. These morphological changes in the patterns for the glycerol solutions were in agreement with the computer simulations based on the diffusion limited aggregation model. The finger tip velocity is proportional to the ratio of the injection pressure to viscosity according to Darcy's law prediction. In contrast, for HPMC solutions, which show shear-thinning, highly branched pattern only appeared when the injection pressure was changed. When isopropyl alcohol was added to HPMC solutions, a morphological transition from highly branched pattern to tip splitting one was observed. The transition in the pattern would be related to changes in both elastic properties and surface tension. The finger tip velocity of HPMC solutions is scaled with 1.5 power of the ratio of injection pressure to viscosity.

  13. 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

    Multilayer tandem polymer solar cells were prepared by solution processing using thermocleavable polymer materials that allow for conversion to an insoluble state through a short thermal treatment. The problems associated with solubility during application of subsequent layers in the stack were...... 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...

  14. Influences of dehydration and rehydration on the lubrication properties of phospholipid polymer-grafted cross-linked polyethylene.

    Science.gov (United States)

    Yarimitsu, Seido; Moro, Toru; Kyomoto, Masayuki; Watanabe, Kenichi; Tanaka, Sakae; Ishihara, Kazuhiko; Murakami, Teruo

    2015-07-01

    Surface modification by grafting of biocompatible phospholipid polymer onto the surface of artificial joint material has been proposed to reduce the risk of aseptic loosening and improve the durability. Poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC)-grafted cross-linked polyethylene (CLPE) has shown promising results for reducing wear of CLPE. The main lubrication mechanism for the PMPC layer is considered to be the hydration lubrication. In this study, the lubrication properties of PMPC-grafted CLPE were evaluated in reciprocating friction test with rehydration process by unloading in various lubricants. The start-up friction of PMPC-grafted CLPE was reduced, and the damage of PMPC layer was suppressed by rehydration in water or hyaluronic acid solutions. In contrast, the start-up friction of PMPC-grafted CLPE increased in fetal bovine serum solution, and the damage for PMPC layer was quite noticeable. Interestingly, the start-up friction of PMPC-grafted CLPE was reduced in fetal bovine serum solution containing hyaluronic acid, and the damage of the PMPC layer was suppressed. These results indicate that the rehydration by unloading and hyaluronic acid are elemental in maximizing the lubrication effect of hydrated PMPC layer.

  15. 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.

  16. How the World Changes By Going from One- to Two-Dimensional Polymers in Solution.

    Science.gov (United States)

    Schlüter, A Dieter; Payamyar, Payam; Öttinger, Hans Christian

    2016-10-01

    Scaling behavior of one-dimensional (1D) and two-dimensional (2D) polymers in dilute solution is discussed with the goal of stimulating experimental work by chemists, physicists, and material scientists in the emerging field of 2D polymers. The arguments are based on renormalization-group theory, which is explained for a general audience. Many ideas and methods successfully applied to 1D polymers are found not to work if one goes to 2D polymers. The role of the various states exhibiting universal behavior is turned upside down. It is expected that solubility will be a serious challenge for 2D polymers. Therefore, given the crucial importance of solutions in characterization and processing, synthetic concepts are proposed that allow the local bending rigidity and the molar mass to be tuned and the long-range interactions to be engineered, all with the goal of preventing the polymer from falling into flat or compact states. © 2016 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. On turbulent kinetic energy production and dissipation in dilute polymer solutions

    Science.gov (United States)

    Liberzon, A.; Guala, M.; Kinzelbach, W.; Tsinober, A.

    2006-12-01

    Drag reduction by dilute polymer solutions is the most recognized phenomenon in wall-bounded turbulent flows, which is associated with large scales (e.g., velocity scales) in spite of a consensus that polymers act mainly on much smaller scales of velocity derivatives. We demonstrate that drag reduction is only one sort of polymers' effect on a turbulent flow and show how turbulent velocity and velocity derivatives are altered in the presence of dilute polymers, irrespective of drag reduction phenomena. This is an experimental study on the interaction of dilute polymers with a complex three-dimensional turbulent flow with small mean velocity gradients. Lagrangian data (e.g., velocities and velocity gradients) of flow tracers were obtained by using three-dimensional particle tracking velocimetry in an observational volume in the turbulent bulk region, far from the boundaries. The focus is on aspects related to the turbulent kinetic energy (TKE) production, -⟨uiuj⟩Sij (ui is the fluctuating velocity, ⟨uiuj⟩ is the Reynolds stress tensor, and Sij is the mean rate-of-strain tensor), such as an anisotropy of Reynolds stresses and the alignment of the velocity vector field with respect to the eigenframe of Sij, among others. We base our study on the comparison of turbulent quantities in flows of water and of dilute polymer solution, forced in two distinct ways: frictional forcing by smooth rotating disks and inertial forcing by disks with baffles. The comparison of the results from the water and from the dilute polymer solution flows allows a critical examination of the influence of polymers on the TKE production, viscous dissipation, and the related turbulent properties. We conclude with (i) quantification of the direct effect of polymers on the small scales of velocity derivatives, (ii) evidence of an additional dissipation mechanism by the polymers, which is the main reason for the strong inhibition of the viscous dissipation, 2νs2, in a turbulent bulk, (iii

  18. Computational exploration of polymer nanocomposite mechanical property modification via cross-linking topology

    Energy Technology Data Exchange (ETDEWEB)

    Lacevic, N; Gee, R; Saab, A; Maxwell, R

    2008-04-24

    Molecular dynamics simulations have been performed in order to study the effects of nanoscale filler cross-linking topologies and loading levels on the mechanical properties of a model elastomeric nanocomposite. The model system considered here is constructed from octa-functional polyhedral oligomeric silsesquioxane (POSS) dispersed in a poly(dimethylsiloxane) (PDMS) matrix. Shear moduli, G, have been computed for pure and for filled and unfilled PDMS as a function of cross-linking density, POSS fill loading level, and polymer network topology. The results reported here show that G increases as the cross-linking (covalent bonds formed between the POSS and the PDMS network) density increases. Further, G is found to have a strong dependence on cross-linking topology. The increase in shear modulus, G, for POSS filled PDMS is significantly higher than that for unfilled PDMS cross-linked with standard molecular species, suggesting an enhanced reinforcement mechanism for POSS. In contrast, in blended systems (POSS/PDMS mixture with no cross-linking) G was not observed to significantly increase with POSS loading. Finally, we find intriguing differences in the structural arrangement of bond strains between the cross-linked and the blended systems. In the unfilled PDMS the distribution of highly strained bonds appears to be random, while in the POSS filled system, the strained bonds form a net-like distribution that spans the network. Such a distribution may form a structural network 'holding' the composite together and resulting in increases in G compared to an unfilled, cross-linked system. These results are of importance for engineering of new POSS-based multifunctional materials with tailor-made mechanical properties.

  19. Computational exploration of polymer nanocomposite mechanical property modification via cross-linking topology.

    Science.gov (United States)

    Lacevic, Naida; Gee, Richard H; Saab, Andrew; Maxwell, Robert

    2008-09-28

    Molecular dynamics simulations have been performed in order to study the effects of nanoscale filler cross-linking topologies and loading levels on the mechanical properties of a model elastomeric nanocomposite. The model system considered here is constructed from octafunctional polyhedral oligomeric silsesquioxane (POSS) dispersed in a poly(dimethylsiloxane) (PDMS) matrix. Shear moduli, G, have been computed for pure and for filled and unfilled PDMS as a function of cross-linking density, POSS fill loading level, and polymer network topology. The results reported here show that G increases as the cross-linking (covalent bonds formed between the POSS and the PDMS network) density increases. Further, G is found to have a strong dependence on cross-linking topology. The increase in shear modulus, G, for POSS filled PDMS is significantly higher than that for unfilled PDMS cross-linked with standard molecular species, suggesting an enhanced reinforcement mechanism for POSS. In contrast, in blended systems (POSS/PDMS mixture with no cross-linking) G was not observed to significantly increase with POSS loading. Finally, we find intriguing differences in the structural arrangement of bond strains between the cross-linked and the blended systems. In the unfilled PDMS the distribution of highly strained bonds appears to be random, while in the POSS filled system, the strained bonds form a netlike distribution that spans the network. Such a distribution may form a structural network "holding" the composite together and resulting in increases in G compared to an unfilled, cross-linked system. These results are of importance for engineering of new POSS-based multifunctional materials with tailor-made mechanical properties.

  20. INFLUENCE OF SOLVENT AND POLYMER SORT ON ANOMALOUS RHEOLOGICAL BEHAVIOR OF POLYMER SOLUTION AT HIGH DILUTION

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The rheological behavior of polyvinyl acetate (PVAc) in N,N'-dimethylformamide (DMF), methyl ethyl ketone (MEK), 1,2-dichloroethane (DCE), tetrahydrofuran (THF) and toluene (TOL), polystyrene (PS) in DMF, MEK, DCE, THF and cyclohexane (CYH), and random ethylene-vinyl acetate (EVA) copolymer in DCE, TOL, CYH with and without surfactant of Span80 and in the DCE/CYH solvent mixtures with surfactant of Span80 was examined at high dilution. It was shown that the extent and type of the upsweep or downsweep (anomalous rheological behavior) of the reduced viscosity-concentration curves of these different polymers at high dilution are markedly dependent on the dielectric constant of the solvent and the polarity of the polymer used. The experimental results indicated that the anomalous rheological behavior of EVA copolymer, widely used as a flow improver, is related to its efficiency in reducing viscosity and depressing pour point of crude oil and waxy solvents.

  1. Cross-linked Composite Gel Polymer Electrolyte using Mesoporous Methacrylate-Functionalized SiO2 Nanoparticles for Lithium-Ion Polymer Batteries

    Science.gov (United States)

    Shin, Won-Kyung; Cho, Jinhyun; Kannan, Aravindaraj G.; Lee, Yoon-Sung; Kim, Dong-Won

    2016-05-01

    Liquid electrolytes composed of lithium salt in a mixture of organic solvents have been widely used for lithium-ion batteries. However, the high flammability of the organic solvents can lead to thermal runaway and explosions if the system is accidentally subjected to a short circuit or experiences local overheating. In this work, a cross-linked composite gel polymer electrolyte was prepared and applied to lithium-ion polymer cells as a safer and more reliable electrolyte. Mesoporous SiO2 nanoparticles containing reactive methacrylate groups as cross-linking sites were synthesized and dispersed into the fibrous polyacrylonitrile membrane. They directly reacted with gel electrolyte precursors containing tri(ethylene glycol) diacrylate, resulting in the formation of a cross-linked composite gel polymer electrolyte with high ionic conductivity and favorable interfacial characteristics. The mesoporous SiO2 particles also served as HF scavengers to reduce the HF content in the electrolyte at high temperature. As a result, the cycling performance of the lithium-ion polymer cells with cross-linked composite gel polymer electrolytes employing methacrylate-functionalized mesoporous SiO2 nanoparticles was remarkably improved at elevated temperatures.

  2. Cross-linked Composite Gel Polymer Electrolyte using Mesoporous Methacrylate-Functionalized SiO2 Nanoparticles for Lithium-Ion Polymer Batteries.

    Science.gov (United States)

    Shin, Won-Kyung; Cho, Jinhyun; Kannan, Aravindaraj G; Lee, Yoon-Sung; Kim, Dong-Won

    2016-05-18

    Liquid electrolytes composed of lithium salt in a mixture of organic solvents have been widely used for lithium-ion batteries. However, the high flammability of the organic solvents can lead to thermal runaway and explosions if the system is accidentally subjected to a short circuit or experiences local overheating. In this work, a cross-linked composite gel polymer electrolyte was prepared and applied to lithium-ion polymer cells as a safer and more reliable electrolyte. Mesoporous SiO2 nanoparticles containing reactive methacrylate groups as cross-linking sites were synthesized and dispersed into the fibrous polyacrylonitrile membrane. They directly reacted with gel electrolyte precursors containing tri(ethylene glycol) diacrylate, resulting in the formation of a cross-linked composite gel polymer electrolyte with high ionic conductivity and favorable interfacial characteristics. The mesoporous SiO2 particles also served as HF scavengers to reduce the HF content in the electrolyte at high temperature. As a result, the cycling performance of the lithium-ion polymer cells with cross-linked composite gel polymer electrolytes employing methacrylate-functionalized mesoporous SiO2 nanoparticles was remarkably improved at elevated temperatures.

  3. Cross-linked Composite Gel Polymer Electrolyte using Mesoporous Methacrylate-Functionalized SiO2 Nanoparticles for Lithium-Ion Polymer Batteries

    Science.gov (United States)

    Shin, Won-Kyung; Cho, Jinhyun; Kannan, Aravindaraj G.; Lee, Yoon-Sung; Kim, Dong-Won

    2016-01-01

    Liquid electrolytes composed of lithium salt in a mixture of organic solvents have been widely used for lithium-ion batteries. However, the high flammability of the organic solvents can lead to thermal runaway and explosions if the system is accidentally subjected to a short circuit or experiences local overheating. In this work, a cross-linked composite gel polymer electrolyte was prepared and applied to lithium-ion polymer cells as a safer and more reliable electrolyte. Mesoporous SiO2 nanoparticles containing reactive methacrylate groups as cross-linking sites were synthesized and dispersed into the fibrous polyacrylonitrile membrane. They directly reacted with gel electrolyte precursors containing tri(ethylene glycol) diacrylate, resulting in the formation of a cross-linked composite gel polymer electrolyte with high ionic conductivity and favorable interfacial characteristics. The mesoporous SiO2 particles also served as HF scavengers to reduce the HF content in the electrolyte at high temperature. As a result, the cycling performance of the lithium-ion polymer cells with cross-linked composite gel polymer electrolytes employing methacrylate-functionalized mesoporous SiO2 nanoparticles was remarkably improved at elevated temperatures. PMID:27189842

  4. Modeling lower critical solution temperature behavior of associating polymer brushes with classical density functional theory.

    Science.gov (United States)

    Gong, Kai; Marshall, Bennett D; Chapman, Walter G

    2013-09-07

    We study the lower critical solution temperature (LCST) behavior of associating polymer brushes (i.e., poly(N-isopropylacrylamide)) using classical density functional theory. Without using any empirical or temperature-dependent parameters, we find the phase transition of polymer brushes from extended to collapsed structure with increasing temperature, indicating the LCST behavior of polymer brushes. The LCST behavior of associating polymer brushes is attributed to the interplay of hydrogen bonding interactions and Lennard-Jones attractions in the system. The effect of grafting density and molecular weight on the phase behavior of associating polymer brushes has been also investigated. We find no LCST behavior at low grafting density or molecular weight. Moreover, increasing grafting density decreases the LCST and swelling ratio of polymer brushes. Similarly, increasing molecular weight decreases the LCST but increases the swelling ratio. At very high grafting density, a partial collapsed structure appears near the LCST. Qualitatively consistent with experiments, our results provide insight into the molecular mechanism of LCST behavior of associating polymer brushes.

  5. 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

    interaction. Polymers bearing shorter PS blocks gave gels with relatively long linear response followed by strain hardening before shear thinning while the longer PS blocks lead to formation of elastic but brittle gels with limited linear regime before shear thinning. Star-block copolymers showed more elastic...... that the thermal properties of the gels are changed by increasing the PS block lengths. Gels with short PS blocks soften upon heating at lower temperatures compared with the gels with longer PS blocks....

  6. Use of pH-sensitive polymer hydrogels in lead removal from aqueous solution.

    Science.gov (United States)

    Ramírez, Elizabeth; Burillo, S Guillermina; Barrera-Díaz, C; Roa, Gabriela; Bilyeu, Bryan

    2011-08-30

    Three gamma crosslinked polymeric hydrogels were synthesized and evaluated as lead ion sorbents. A crosslinked poly(acrylic acid) hydrogel was compared with two 4-vinylpiridine-grafted poly(acrylic acid) hydrogels (26.74 and 48.1% 4-vinylpiridine). The retention properties for Pb(II) from aqueous solutions of these three polymers were investigated by batch equilibrium procedure. The effects of pH, contact time and Pb(II) concentration were evaluated. The optimal pH range for all polymers was 4-6. The lightly grafted polymer (PAAc-g-4VP at 26.74%) exhibited a Pb(II) removal close to 80% at 5h and above 90% at 24h. The maximum Pb(II) removal was 117.9mg g(-1) of polymer and followed the Freundlich adsorption model. XPS characterization indicates that the carboxyl groups are involved in the Pb(II) removal.

  7. Quasi-elastic neutron scattering study on water and polymer dynamics in thermo/pressure sensitive polymer solutions.

    Science.gov (United States)

    Osaka, Noboru; Shibayama, Mitsuhiro; Kikuchi, Tatsuya; Yamamuro, Osamu

    2009-10-01

    Dynamics of water and poly(N-isopropylacrylamide) (PNIPA) in concentrated aqueous solutions, where the majority of water molecules are attached to polymer chains, has been investigated with use of incoherent quasi-elastic neutron scattering (QENS) and dynamic light scattering (DLS) measurements as functions of temperature, T, and hydrostatic pressure, P. It was observed by QENS that the self-diffusion coefficient, D(water), of water in PNIPA/H(2)O solutions increased by P at temperatures below the lower critical solution temperature (LCST) of PNIPA aqueous solutions. However, above the LCST, D(water) decreased by P, as is often reported in non-hydrogen bonding solutions. In isobaric heating runs, therefore, the jump in D(water) at LCST decreased with increasing pressure. On the other hand, the mean-square displacement, , of the local vibrational motion of PNIPA in PNIPA/D(2)O solutions, where the incoherent scattering signal of PNIPA was predominantly observed, was reduced due to the aggregation behavior of PNIPA by pressurizing, which was also confirmed by using DLS. The jump in at the LCST became gradual by pressurizing, which was consistent with the changes of the dynamics of water obtained in PNIPA/H(2)O solutions.

  8. Flow-enhanced solution printing of all-polymer solar cells.

    Science.gov (United States)

    Diao, Ying; Zhou, Yan; Kurosawa, Tadanori; Shaw, Leo; Wang, Cheng; Park, Steve; Guo, Yikun; Reinspach, Julia A; Gu, Kevin; Gu, Xiaodan; Tee, Benjamin C K; Pang, Changhyun; Yan, Hongping; Zhao, Dahui; Toney, Michael F; Mannsfeld, Stefan C B; Bao, Zhenan

    2015-08-12

    Morphology control of solution coated solar cell materials presents a key challenge limiting their device performance and commercial viability. Here we present a new concept for controlling phase separation during solution printing using an all-polymer bulk heterojunction solar cell as a model system. The key aspect of our method lies in the design of fluid flow using a microstructured printing blade, on the basis of the hypothesis of flow-induced polymer crystallization. Our flow design resulted in a ∼90% increase in the donor thin film crystallinity and reduced microphase separated donor and acceptor domain sizes. The improved morphology enhanced all metrics of solar cell device performance across various printing conditions, specifically leading to higher short-circuit current, fill factor, open circuit voltage and significantly reduced device-to-device variation. We expect our design concept to have broad applications beyond all-polymer solar cells because of its simplicity and versatility.

  9. Direct Uniaxial Alignment of a Donor-Acceptor Semiconducting Polymer Using Single-Step Solution Shearing.

    Science.gov (United States)

    Shaw, Leo; Hayoz, Pascal; Diao, Ying; Reinspach, Julia Antonia; To, John W F; Toney, Michael F; Weitz, R Thomas; Bao, Zhenan

    2016-04-13

    The alignment of organic semiconductors (OSCs) in the active layers of electronic devices can confer desirable properties, such as enhanced charge transport properties due to better ordering, charge transport anisotropy for reduced device cross-talk, and polarized light emission or absorption. The solution-based deposition of highly aligned small molecule OSCs has been widely demonstrated, but the alignment of polymeric OSCs in thin films deposited directly from solution has typically required surface templating or complex pre- or postdeposition processing. Therefore, single-step solution processing and the charge transport enhancement afforded by alignment continue to be attractive. We report here the use of solution shearing to tune the degree of alignment in poly(diketopyrrolopyrrole-terthiophene) thin films by controlling the coating speed. A maximum dichroic ratio of ∼7 was achieved on unpatterned substrates without any additional pre- or postdeposition processing. The degree of polymer alignment was found to be a competition between the shear alignment of polymer chains in solution and the complex thin film drying process. Contrary to previous reports, no charge transport anisotropy was observed because of the small crystallite size relative to the channel length, a meshlike morphology, and the likelihood of increased grain boundaries in the direction transverse to coating. In fact, the lack of aligned morphological structures, coupled with observed anisotropy in X-ray diffraction data, suggests the alignment of polymer molecules in both the crystalline and the amorphous regions of the films. The shear speed at which maximum dichroism is achieved can be controlled by altering deposition parameters such as temperature and substrate treatment. Modest changes in molecular weight showed negligible effects on alignment, while longer polymer alkyl side chains were found to reduce the degree of alignment. This work demonstrates that solution shearing can be used

  10. Polymeric Nanocapsule from Silica Nanoparticle@Cross-linked Polymer Nanoparticles via One-Pot Approach

    Directory of Open Access Journals (Sweden)

    Shen Ruoping

    2009-01-01

    Full Text Available Abstract A facile strategy was developed here to prepare cross-linked polymeric nanocapsules (CP nanocapsules with silica nanoparticles as templates. The silica nanoparticle@cross-linked polymer nanoparticles were prepared by the encapsulation of the silica nanoparticles by the one-pot approach via surface-initiated atom transfer radical polymerization of hydroxyethyl acrylate in the presence ofN,N′-methylenebisacrylamide as a cross-linker from the initiator-modified silica nanoparticles. After the silica nanoparticle templates were etched with hydrofluoric acid, the CP nanocapsules with particle size of about 100 nm were obtained. The strategy developed was confirmed with Fourier transform infrared, thermogravimetric analysis and transmission electron microscopy.

  11. Preparation, Characterization and Efficacy Evaluation of Synthetic Biocompatible Polymers Linking Natural Antioxidants

    Directory of Open Access Journals (Sweden)

    Nevio Picci

    2012-10-01

    Full Text Available The purpose of this work was the synthesis, characterization and efficacy evaluation of new biocompatible antioxidant polymers linking trans-ferulic acid or a-lipoic acid. In particular, ferulic or lipoic acid were introduced in the preformed polymeric backbone. The new antioxidant biopolymers were characterized by Fourier transform infrared spectroscopy and gel permeation chromatography. The degree of functionalization (moles of antioxidant per gram of polymer was determined by the Gaur-Gupta method for free amino group determination and by the Folin method for the phenolic groups. Their ability to inhibit lipid peroxidation were estimated in rat liver microsomal membranes induced in vitro by tert-BOOH (tert-butyl hydroperoxide, as a source of free radicals. The DPPH (1,1-diphenyl-2-picrylhydrazyl radical-scavenging effect was also evaluated. The obtained systems, with different solubility, showed strong antioxidant and antiradical activities, suggesting potential use as packaging materials for foods, cosmetics, pharmaceuticals and personal care products. Moreover, the cytotoxicity of the synthesized polymers was also evaluated on Caco-2 cell cultures in order to verify their biocompatibility when exposed to an absorptive epithelial cell line.

  12. Physico-chemical durability criteria of oils and linked bio-based polymers

    Directory of Open Access Journals (Sweden)

    Irshad Ambreen

    2015-01-01

    Full Text Available The oxidative stability or durability is an important indicator of performance that depends on the composition of the sample. The fatty oil or polymer degradation processes have generally been established as being free radical mechanism yielding primary oxidation products. We propose to explain in detail all the analytical methods and tools used for the determination of the initial physico-chemical properties of oils and the properties in ageing conditions. Chemical titrations for acid or peroxide value, Rancimat method or thermogravimetric measurements are discussed. Accelerated ageing tools for thermal or photochemical exposures are also shown. After the assessment of oil durability, the development of new bio-based polymer with vegetable oil is tackled because of its industrial interest. It is essential to understand the long term behavior of oils and biopolymers and to assess exactly the durability which is useful to produce life cycle analysis of materials. At last we underline the advantages of a new Fourier transform infrared (FTIR instrumentation with in-situ irradiation and gas cell to give a screening of the durability of various oils or polymers. Main durability criteria of oils and biopolymers are linked to the production of volatile organic compounds and the resistance to the oxidation process.

  13. Preparation, characterization and efficacy evaluation of synthetic biocompatible polymers linking natural antioxidants.

    Science.gov (United States)

    Trombino, Sonia; Cassano, Roberta; Ferrarelli, Teresa; Leta, Sonia; Puoci, Francesco; Picci, Nevio

    2012-10-26

    The purpose of this work was the synthesis, characterization and efficacy evaluation of new biocompatible antioxidant polymers linking trans-ferulic acid or a-lipoic acid. In particular, ferulic or lipoic acid were introduced in the preformed polymeric backbone. The new antioxidant biopolymers were characterized by Fourier transform infrared spectroscopy and gel permeation chromatography. The degree of functionalization (moles of antioxidant per gram of polymer) was determined by the Gaur-Gupta method for free amino group determination and by the Folin method for the phenolic groups. Their ability to inhibit lipid peroxidation were estimated in rat liver microsomal membranes induced in vitro by tert-BOOH (tert-butyl hydroperoxide), as a source of free radicals. The DPPH (1,1-diphenyl-2-picrylhydrazyl) radical-scavenging effect was also evaluated. The obtained systems, with different solubility, showed strong antioxidant and antiradical activities, suggesting potential use as packaging materials for foods, cosmetics, pharmaceuticals and personal care products. Moreover, the cytotoxicity of the synthesized polymers was also evaluated on Caco-2 cell cultures in order to verify their biocompatibility when exposed to an absorptive epithelial cell line.

  14. Liquid-liquid equilibria for binary and ternary polymer solutions with PC-SAFT

    DEFF Research Database (Denmark)

    Lindvig, Thomas; Michelsen, Michael Locht; Kontogeorgis, Georgios

    2004-01-01

    Two algorithms for evaluating liquid-liquid equilibria (LLE) for binary and ternary polymer solutions are presented. The binary algorithm provides the temperature versus concentration cloud-point curve at fixed pressure, whereas the ternary algorithm provides component 1 versus component 2...

  15. Prediction of Solution Properties of Flexible-Chain Polymers: A Computer Simulation Undergraduate Experiment

    Science.gov (United States)

    de la Torre, Jose Garcia; Cifre, Jose G. Hernandez; Martinez, M. Carmen Lopez

    2008-01-01

    This paper describes a computational exercise at undergraduate level that demonstrates the employment of Monte Carlo simulation to study the conformational statistics of flexible polymer chains, and to predict solution properties. Three simple chain models, including excluded volume interactions, have been implemented in a public-domain computer…

  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. Tension, rigidity and preferential curvature of interfaces between coexisting polymer solutions

    NARCIS (Netherlands)

    Tromp, R.H.; Blokhuis, E.M.

    2013-01-01

    The properties of the interface in a phase-separated solution of polymers with different degrees of polymerization and Kuhn segment lengths are calculated. The starting point is the planar interface, the profile of which is calculated in the so-called “blob model”, which incorporates the solvent in

  18. Effect of stretching-induced changes in hydrodynamic screening on coil-stretch hysteresis of unentangled polymer solutions

    Science.gov (United States)

    Prabhakar, Ranganathan; Sasmal, Chandi; Nguyen, Duc At; Sridhar, Tam; Prakash, J. Ravi

    2017-01-01

    Extensional rheometry and Brownian dynamics simulations of flexible polymer solutions confirm predictions based on blob concepts that coil-stretch hysteresis in extensional flows increases with concentration, reaching a maximum at the critical overlap concentration c* before progressively vanishing in the semidilute regime. These observations demonstrate that chain stretching strengthens intermolecular hydrodynamic screening in dilute solutions, but weakens it in semidilute solutions. Flow can thus strongly modify the concentration dependence of viscoelastic properties of polymer solutions.

  19. Flow of Viscoelastic Polymer Solutions through Filter Screens

    Science.gov (United States)

    Machač, Ivan; Surý, Alexander; Šiška, Bedřich

    2011-07-01

    In this contribution, the measurements are presented of the pressure drop in the creeping flow of viscoelastic solution of polyacrylamides through metal wire screens, differing in wire diameter, aperture dimension, and type of weaving. In this flow, a strong elastic pressure drop excess manifest itself. Analysing the extensive set of experimental data, it was verified that for engineering estimation of the pressure drop excess, a simple form of the corrective Deborah number function can be used.

  20. Skin formation and bubble growth during drying process of polymer solution.

    Science.gov (United States)

    Arai, S; Doi, M

    2012-07-01

    When a polymer solution with volatile solvent is dried, skins are often formed at the surface of the solution. It has been observed that after the skin is formed, bubbles often appear in the solution. We conducted experiments to clarify the relation between the skin formation and the bubble formation. We measured the time dependence of the thickness of the skin layer, the size of the bubbles, and the pressure in the solution. From our experiments, we concluded that i) the gas in the bubble is a mixture of solvent vapor and air dissolved in the solution, ii) the bubble nucleation is assisted by the pressure decrease in the solution covered by the skin layer, and iii) the growth of the bubbles is diffusion limited, mainly limited by the diffusion of air molecules dissolved in the solution.

  1. HaidaLink : a clean energy solution for Haida Gwaii

    Energy Technology Data Exchange (ETDEWEB)

    Burns, M. [NaiKun Wind Development Inc., Vancouver, BC (Canada)

    2007-07-01

    NaiKun Wind Energy Group has worked in partnership with First Nations and the wind power industry to meet the energy needs of remote communities in British Columbia. NaiKun developed North America's first offshore wind project. This presentation introduced NaiKun's proposed HaidaLink Project connecting Haida Gwaii to the BC electricity grid via an underwater cable. Approximately 100 turbines in the Hecate Strait currently provide 320 MW of wind energy. NaiKun has contributed to the objectives of Haida Gwaii which include the preservation and stewardship of Haida Gwaii; develop employment potential; provide income for the community; manage new resource development; and, replace diesel generation. Currently, there are 3 generating stations on Haida Gwaii, notably 2 diesel and 1 hydro. In 2006, the load was 52 GWh. The northern and southern grids are not connected. Greenhouse gas emissions are 26,000 tonnes per year and economic growth is impeded by the poor reliability and quality of power. The community is in support of displacing diesel generation. The first phase of NaiKun's HaidaLink project involves the installation of a 50 km, 70 kV cable to connect Haida Gwaii with the BC grid. The $54 million project depends on approval and participation of BC Hydro and the British Columbia Utilities Commission, and is contingent upon completion of an environmental impact assessment. figs.

  2. Effect of some anionic polymers on pH of triethanolamine aqueous solutions.

    Science.gov (United States)

    Musiał, Witold; Kubis, Aleksander

    2004-01-01

    One of the suggested approaches in the management and prophylaxis of acne involves binding of free fatty acids in the form of soap with alcoholamines. Due to a possible irritating effect of alcoholamines associated with a relatively high pH of their aqueous solutions, complexation of alcoholamines with acid polymers is advocated. Triethanolamine is one of the best recognized alcoholamines. It was conventionally neutralized with Carbopols, Eudragits, alginic acid and pectin. During neutralization of polymer dispersions with triethanolamine, variations in the course of the neutralization curve have been observed among individual macromolecular compounds. The pH of 0.1 mol/l triethanolamine solution reaches 10.51, while following a complete neutralization with anionic polymers, such as Carbopols, Eudragits, alginic acid and pectin, pH ranges from 3.88 for systems neutralized with alginic acid to 8.50 for the system neutralized with Eudragit S-100. Complexation of triethanolamine with anionic polymers decreases its pH, and it is possible to find such pH range in which pH of the preparation containing the polymer and triethanolamine will correspond to the physiological pH of the skin.

  3. Phase behavior and second osmotic virial coefficient for competitive polymer solvation in mixed solvent solutions.

    Science.gov (United States)

    Dudowicz, Jacek; Freed, Karl F; Douglas, Jack F

    2015-11-21

    We apply our recently developed generalized Flory-Huggins (FH) type theory for the competitive solvation of polymers by two mixed solvents to explain general trends in the variation of phase boundaries and solvent quality (quantified by the second osmotic virial coefficient B2) with solvent composition. The complexity of the theoretically predicted miscibility patterns for these ternary mixtures arises from the competitive association between the polymer and the solvents and from the interplay of these associative interactions with the weak van der Waals interactions between all components of the mixture. The main focus here lies in determining the influence of the free energy parameters for polymer-solvent association (solvation) and the effective FH interaction parameters {χαβ} (driving phase separation) on the phase boundaries (specifically the spinodals), the second osmotic virial coefficient B2, and the relation between the positions of the spinodal curves and the theta temperatures at which B2 vanishes. Our classification of the predicted miscibility patterns is relevant to numerous applications of ternary polymer solutions in industrial formulations and the use of mixed solvent systems for polymer characterization, such as chromatographic separation where mixed solvents are commonly employed. A favorable comparison of B2 with experimental data for poly(methyl methacrylate)/acetonitrile/methanol (or 1-propanol) solutions only partially supports the validity of our theoretical predictions due to the lack of enough experimental data and the neglect of the self and mutual association of the solvents.

  4. Current applications of foams formed from mixed surfactant-polymer solutions.

    Science.gov (United States)

    Bureiko, Andrei; Trybala, Anna; Kovalchuk, Nina; Starov, Victor

    2015-08-01

    Foams cannot be generated without the use of special foaming agents, as pure liquids do not foam. The most common foaming agents are surfactants, however often for foam stability one active agent is not enough, it is necessary to add other component to increase foam lifetime. Foams on everyday use are mostly made from mixture of different components. Properly chosen combinations of two active ingredients lead to a faster foam formation and increased foam stability. During the last decade polymers (mainly polyelectrolytes and proteins) have become frequently used additives to foaming solutions. Mixtures of surfactants and polymers often demonstrate different foaming properties in comparison to surfactant only or polymer only solutions. The nature of surfactant-polymer interactions is complicated and prediction of resulting foaming properties of such formulations is not straightforward. Properties and foaming of surfactant-polymer mixtures are discussed as well as current applications of foams and foaming agents as foams are widely used in cosmetics, pharmaceutics, medicine and the food industry.

  5. New Aptes Cross-linked Polymers from Poly(ethylene oxide)s and Cyanuric Chloride for Lithium Batteries

    Science.gov (United States)

    Tigelaar, Dean M.; Meador, Mary Ann B.; Kinder, James D.; Bennett, William R.

    2005-01-01

    A new series of polymer electrolytes for use as membranes for lithium batteries are described. Electrolytes were made by polymerization between cyanuric chloride and diamino-terminated poly(ethylene oxide)s, followed by cross-linking via a sol-gel process. Thermal analysis and lithium conductivity of freestanding polymer films were studied. The effects of several variables on conductivity were investigated, such as length of backbone PEO chain, length of branching PEO chain, extent of branching, extent of cross-linking, salt content, and salt counterion. Polymer films with the highest percentage of PEO were found to be the most conductive, with a maximum lithium conductivity of 3.9 x 10(exp -5) S/cm at 25 C. Addition of plasticizer to the dry polymers increased conductivity by an order of magnitude.

  6. Preparation of Laminin-apatite-polymer Composites Using Metastable Calcium Phosphate Solutions

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A synthetic polymer with a laminin-apatite composite layer on its surface would be useful as a percutaneous device. The preparation of such a composite was attempted in the present study using poly ( ethylene terephthalate ) (PET) and polyethylene ( PE ) as the synthetic polymer. PET and PE plates and those pretreated with an oxygen plasma were alternately dipped in calcium and phosphate ion solutions, and then immersed in a metastable ealcium phosphate solution supplemented with laminin ( LCP solution ). The PET and PE plates pretreated with an oxygen plasma formed a uniform and continuous layer of a laminin- apatite composite on their surfaces. In contrast, the PET and PE plates that had not been pretreated with an oxygen plasma did not form a continuous layer of a laminin-apatite composite on their surfaces. The hydrophilic functional groups on the PET and PE surfaces introduced by the plasma treatment were responsible for the successful laminin-apatite composite coating.

  7. Solution Behavior of Modified Polyethylenimine (PEI) Polymers by Light Scattering Investigations

    Energy Technology Data Exchange (ETDEWEB)

    Sonny A. Ekhorutomwen; Samuel P. Sawan; Barbara F. Smith; Thomas W. Robison; Kennard V. Wilson

    2004-03-18

    The eight average molecular weights, as well as other characteristics such as the second virial coefficients and root-mean-square (RMS) radii of gyration of poly (ethyleneimine) (PEI) and various derivatives, have been determined in solution light scattering studies. The solution dynamics of PEI and carboxylated and phosphorylated derivatives were studied a pH of 3.3, 7.0 and 10.0. Measurements were made in freshly distilled and de-ionized water as well as in 0.1 M, 1 M and 5-M solutions of sodium chloride in water. Molecular weights were calculated from Berry plots. The purified polymer, PEI-1, gave a molecular weight of 39,600 g/mol., while the same polymer, which was not purified, PEI-2, has MW of 43,100 g/mol.

  8. A solution state diode using semiconductor polymer nanorods with nanogap electrodes.

    Science.gov (United States)

    Mutlu, Senol; Sonmez, Bedri Gurkan

    2012-06-22

    A solution state polymer diode, which uses regioregular poly(3-hexylthiophene-2,5-diyl) (P3HT):dichlorobenzene solution as the semiconductor between highly doped p-type silicon and aluminum electrodes has been built. Electrodes separated by a 40 nm gap enable intra-chain charge carrier transfer through the lengths of single polymer chains. This prevents chain to chain hopping and chain entanglements, increasing carrier mobility. The degradation with time and hysteresis effects of the diodes are measured. An optimal P3HT solution concentration of 6 mg ml(-1) is found. A current density of at least 300 mA cm(-2) is achieved, indicating at least a six-fold improvement in carrier mobility compared to previously fabricated solid state P3HT diodes.

  9. Diffusion in Evaporating Polymer Solutions: A Model in the Dissipative Formalism of Nonequilibrium Thermodynamics

    CERN Document Server

    Es-haghi, Siamak Shams

    2012-01-01

    In this paper, diffusion in polymer solutions undergoing evaporation of solvent is modeled as a coupled heat and mass transfer problem with moving boundary condition within the framework of nonequilibrium thermodynamics. The proposed governing equations derived from the fundamental equation of classical thermodynamics using the local equilibrium hypothesis display more complex connection between heat and non-convective mass fluxes than what has been presented in the previous research works. Numerical computations, performed using an explicit finite difference scheme, indicate that the model is able to capture the effect of thermal diffusion in polymer solutions. This effect manifests itself as an increase in local concentration of solvent near warm substrates during solution casting process.

  10. Displacement of polymer solution on residual oil trapped in dead ends

    Institute of Scientific and Technical Information of China (English)

    张立娟; 岳湘安

    2008-01-01

    For waterflooding reservoir,oil trapped in pore’s dead ends is hardly flushed out,and usually becomes one typical type of residual oil.The microscopic displacement characteristics of polymer solution with varied viscoelastic property were studied by numerical and experimental method.According to main pore structure characteristics and rheological property of polymer solution through porous media,displacement models for residual oil trapped in dead ends were proposed,and upper-convected Maxwell rheological model was used as polymer solution’s constitutive equation.The flow and stress field was given and displacement characteristic was quantified by introducing a parameter of micro swept coefficient.The calculated and experimental results show that micro swept coefficient rises with the increase of viscoelasticity;for greater viscoelasticity of polymer solution,vortices in the dead end have greater swept volume and displacing force on oil,and consequently entraining the swept oil in time.In addition,micro swept coefficient in dead end is function of the inclination angle(θ) between pore and dead end.The smaller of θ and 180-θ,the flow field of viscoelastic fluid is developed in dead ends more deeply,resulting in more contact with oil and larger swept coefficient.

  11. 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 (MoS2) 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 depressants

  12. Solution-processed cathode interfacial layer materials for high-efficiency polymer solar cells

    Directory of Open Access Journals (Sweden)

    Biao Xiao

    2015-09-01

    Full Text Available Polymer solar cells (PSCs are a new type of renewable energy source currently being extensively investigated due to perceived advantages; such as being lightweight, low-cost and because of the unlimited materials resource. The power conversion efficiency of state-of-the-art PSCs has increased dramatically in the past few years, obtained mainly through the development of new electron donor polymers, acceptors, and novel device structures through the use of various electrode interfacial materials. In this short review, recent progress in solution-processed cathode interfacial layers that could significantly improve device performances is summarized and highlighted.

  13. AN UNSTEADY SEEPAGE FLOW MODEL OF VISCO-ELASTIC POLYMER SOLUTION

    Institute of Scientific and Technical Information of China (English)

    YIN Hong-jun; FU Chun-quan; LV Yan-ping

    2004-01-01

    With the consideration of the visco-elasticity,the adsorption effect and the variation of rheological parameters, a seepage flow model of visco-elastic polymer solutions was established. The model was numerically treated with the finite difference method. Then curves of Bottom Hole Pressure (BHP) and formation pressure were drawn. The influences of the relaxation time, the injection rate, the permeability reduction co efficient, the consistency coefficient and the power-law exponent of the injected fluid on pressure performance were analyzed. This study shows that it is necessary to consider the visco-elasticity of non-Newtonian fluid in analyzing of pressure performance in the polymer flooding.

  14. Networking properties of cyclodextrin-based cross-linked polymers probed by inelastic light-scattering experiments.

    Science.gov (United States)

    Rossi, Barbara; Caponi, Silvia; Castiglione, Franca; Corezzi, Silvia; Fontana, Aldo; Giarola, Marco; Mariotto, Gino; Mele, Andrea; Petrillo, Caterina; Trotta, Francesco; Viliani, Gabriele

    2012-05-03

    An integrated experimental approach, based on inelastic light-scattering techniques, has been here employed for a multilength scale characterization of networking properties of cyclodextrin nanosponges, a new class of cross-linked polymeric materials built up from natural oligosaccharides cyclodextrins. By using Raman and Brillouin scattering experiments, we performed a detailed inspection of the vibrational dynamics of these polymers over a wide frequency window ranging from gigahertz to terahertz, with the aim of providing physical descriptors correlated to the cross-linking degree and elastic properties of the material. The results seem to suggest that the stiffness of cross-linked polymers can be successfully tuned by acting on the type and the relative amount of the cross-linker during the synthesis of a polymer matrix, predicting and controlling their swelling and entrapment properties. The proposed experimental approach is a useful tool for investigating the structural and physicochemical properties of polymeric network systems.

  15. Dynamics of single semiflexible polymers in dilute solution

    Science.gov (United States)

    Nikoubashman, Arash; Milchev, Andrey; Binder, Kurt

    2016-12-01

    We study the dynamics of a single semiflexible chain in solution using computer simulations, where we systematically investigate the effect of excluded volume, chain stiffness, and hydrodynamic interactions. We achieve excellent agreement with previous theoretical considerations, but find that the crossover from the time τb, up to which free ballistic motion of the monomers describes the chain dynamics, to the times W-1 or τ0, where anomalous monomer diffusion described by Rouse-type and Zimm-type models sets in, requires two decades of time. While in the limit of fully flexible chains the visibility of the anomalous diffusion behavior is thus rather restricted, the t3/4 power law predicted for stiff chains without hydrodynamic interactions is verified. Including hydrodynamics, evidence for the predicted [tln (t ) ] 3 /4 behavior is obtained. Similar good agreement with previous theoretical predictions is found for the decay of the bond autocorrelation functions and the end-to-end vector correlation. Finally, several predictions on the variation of characteristic relaxation times with persistence length describing the chain stiffness are tested.

  16. Polymer-additive extraction via pressurized fluids and organic solvents of variously cross-linked poly(methylmethacrylates).

    Science.gov (United States)

    Nazem, N; Taylor, L T

    2002-04-01

    Variously cross-linked poly(methylmethacrylates) (PMMAs) are synthesized with three additives incorporated at theoretically 1000 microg of the additive per gram of prepared polymer. The additives are Irganox 1010, Irganox 1076, and Irgafos 168. The in-house" synthesized polyacrylates are then subjected to supercritical fluid extraction (SFE) to determine if additive recovery is a function of percent cross-linking. Although considerable work in this regard has been performed with non-cross-linked polyolefins, the literature is lacking regarding polyacrylates. Some additive degradation apparently occurs during the synthesis, as judged by the increased complexity of the extract high-performance liquid chromatographic trace and the low percent recoveries observed especially for the Irganoxes. For low polymer cross-linking (1%), it appears that both PMMA synthetic reproducibility and readily observed polymer swelling during SFE are serious issues that adversely affect additive percent recovery and precision of results. Higher percent cross-linking yields more consistent analytical data than low percent cross-linking, even though the amount of additive extracted in all PMMA samples (regardless of cross-linking percentage) is essentially the same whether the extraction is via SFE or liquid-solid extraction with methylene chloride. Results for comparably cross-linked poly(ethylmethacrylate) and poly(butylmethacrylate) are similar to PMMA.

  17. Biodegradable Polycaprolactone as Ion Solvating Polymer for Solution-Processed Light-Emitting Electrochemical Cells

    Science.gov (United States)

    Jürgensen, Nils; Zimmermann, Johannes; Morfa, Anthony John; Hernandez-Sosa, Gerardo

    2016-11-01

    In this work, we demonstrate the use of the biodegradable polymer polycaprolactone (PCL) as the ion solvating polymer in solution-processed light-emitting electrochemical cells (LEC). We show that the inclusion of PCL in the active layer yields higher ionic conductivities and thus contributes to a rapid formation of the dynamic p-i-n junction and reduction of operating voltages. PCL shows no phase separation with the emitter polymer and reduces film roughness. The devices show light-emission at voltages as low as 3.2 V and lifetimes on the order of 30 h operating above 150 cd m‑2 with turn-on times <20 s and current and luminous efficacies of 3.2 Cd A‑1 and 1.5 lm W‑1 respectively.

  18. Henry constants in polymer solutions with the van der Waals equation of state

    DEFF Research Database (Denmark)

    Bithas, Sotiris; Kalospiros, Nikolaos; Kontogeorgis, Georgios

    1996-01-01

    The simple der Waals equation of state, as extended to polymer systems, is applied to the correlation and prediction of Henry constants in polymer solutions comprising five polymers and many nonpolar and polar solvents, including supercritical gases. The correlation achieved with one adjustable...... parameter is satisfactory, with typical errors within the experimental uncertainty and comparable to those with the more complex Perturbed Hard Chain Theory-based equations of state with the same number of adjustable parameters. A predictive scheme for calculating Henry constants is also presented, which...... is a corresponding-states correlation for a dimensionless Henry constant defined based on the van der Waals equation of state. Satisfactory results-often close to the ones from the one-parameter correlation-are obtained for all systems investigated in this work. Compared with literature models that have been applied...

  19. 100G shortwave wavelength division multiplexing solutions for multimode fiber data links

    DEFF Research Database (Denmark)

    Cimoli, Bruno; Estaran Tolosa, Jose Manuel; Rodes Lopez, Guillermo Arturo

    2016-01-01

    We investigate an alternative 100G solution for optical short-range data center links. The presented solution adopts wavelength division multiplexing technology to transmit four channels of 25G over a multimode fiber. A comparative performance analysis of the wavelength-grid selection for the wav...

  20. Linking water age and solute dynamics in streamflow at the Hubbard Brook Experimental Forest, NH, USA

    Science.gov (United States)

    Paolo Benettin; Scott W. Bailey; John L. Campbell; Mark B. Green; Andrea Rinaldo; Gene E. Likens; Kevin J. McGuire; Gianluca Botter

    2015-01-01

    We combine experimental and modeling results from a headwater catchment at the Hubbard Brook Experimental Forest (HBEF), New Hampshire, USA, to explore the link between stream solute dynamics and water age. A theoretical framework based on water age dynamics, which represents a general basis for characterizing solute transport at the catchment scale, is here applied to...

  1. Polymer solutions in co-rotating Taylor-Couette flow without vorticity

    Science.gov (United States)

    Zell, A.; Wagner, C.

    2012-02-01

    We present experimental results of the flow of dilute and semi-dilute polymer solutions in co-rotating Taylor-Couette cylinders. The experimental set-up consists of a modified Mars II rheometer (Thermo Scientific) with two drive units that are mounted opposite each other. The rotational velocities of the inner and outer cylinders are chosen in a way such that the angular velocity has a 1/r profile and the flow is free of vorticity, but the direction of elongation is not constant, but rotates with the flow. Our particle image velocimetry (PIV) measurements show that for polymer solutions without shear thinning the flow is indeed free of vorticity and is equal to a stagnation point flow at a given position and a given instant in time. In contrast, torque measurements reveal that the stresses are identical to the stresses that are present in a plane shear flow. Thus, we find that for polymer solutions a flow with vorticity and a constant direction of elongation is equal to a flow without vorticity in which the direction of elongation is rotating. Finally, we show that for shear thinning solutions the flow velocity becomes non-monotonic through the gap and resembles a pluglike profile which is known from the Poiseuille flow.

  2. Sodium chloride methanol solution spin-coating process for bulk-heterojunction polymer solar cells

    Science.gov (United States)

    Liu, Tong-Fang; Hu, Yu-Feng; Deng, Zhen-Bo; Li, Xiong; Zhu, Li-Jie; Wang, Yue; Lv, Long-Feng; Wang, Tie-Ning; Lou, Zhi-Dong; Hou, Yan-Bing; Teng, Feng

    2016-08-01

    The sodium chloride methanol solution process is conducted on the conventional poly(3-hexylthiophene) (P3HT)/[6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) polymer bulk heterojunction solar cells. The device exhibits a power conversion efficiency of up to 3.36%, 18% higher than that of the device without the solution process. The measurements of the active layer by x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and ultraviolet photoelectron spectroscopy (UPS) indicate a slight phase separation in the vertical direction and a sodium chloride distributed island-like interface between the active layer and the cathode. The capacitance-voltage (C-V) and impedance spectroscopy measurements prove that the sodium chloride methanol process can reduce the electron injection barrier and improve the interfacial contact of polymer solar cells. Therefore, this one-step solution process not only optimizes the phase separation in the active layers but also forms a cathode buffer layer, which can enhance the generation, transport, and collection of photogenerated charge carriers in the device simultaneously. This work indicates that the inexpensive and non-toxic sodium chloride methanol solution process is an efficient one-step method for the low cost manufacturing of polymer solar cells. Project supported by the Fundamental Research Funds for the Central Universities, China (Grant No. 2014JBZ009) and the National Natural Science Foundation of China (Grant Nos. 61274063, 61377028, 61475014, and 61475017).

  3. FTIR spectroscopy and thermodynamics of hydrogen adsorbed in a cross-linked polymer.

    Science.gov (United States)

    Spoto, Giuseppe; Vitillo, Jenny G; Cocina, Donato; Damin, Alessandro; Bonino, Francesca; Zecchina, Adriano

    2007-09-28

    The adsorption of H(2) in a cross-linked poly(styrene-co-divinylbenzene) (St-DVB) microporous polymer (BET surface area 920 m(2) g(-1)) is studied by volumetric and gravimetric methods, FTIR spectroscopy at variable temperature (300-14 K) and ab initio calculations. At 77 K the polymer reversibly stores up to 1.3 mass% H(2) at a pressure of 1 bar and 1.8 mass% at 10 bar. The adsorption process involves the specific interaction of H(2) with the structural phenyl rings through weak dispersive forces. The interacting molecules become IR active and give rise to vibrational and rotational-vibrational manifestations which are affected by the temperature, the contact time and the H(2) equilibrium pressure. The spectra of the H(2)/St-DVB system reported here represent the first IR evidence of the adsorption of hydrogen on unsaturated molecules. The adsorption enthalpy is evaluated by the VTIR (variable temperature IR spectroscopy) method (C. Otero Areán et al., Phys. Chem. Chem. Phys., 2007, DOI: 10.1039/b615535a) and compared with the results of ab initio calculations for the H(2)/benzene interaction and with literature data.

  4. Silica-shell cross-linked micelles encapsulating fluorescent conjugated polymers for targeted cellular imaging.

    Science.gov (United States)

    Tan, Happy; Zhang, Yu; Wang, Miao; Zhang, Zhongxing; Zhang, Xinhai; Yong, Anna Marie; Wong, Siew Yee; Chang, Alex Yuang-chi; Chen, Zhi-Kuan; Li, Xu; Choolani, Mahesh; Wang, John

    2012-01-01

    A bioinspired silification approach was successfully used to encapsulate fluorescent conjugated polymers inside silica-shell cross-linked polymeric micelles (CP-SSCL) in the highly benign synthesis environment of room temperature and near-neutral aqueous environment. Four different conjugated polymers were employed to demonstrate the versatility of the bioinspired silification, resulting in the formation of CP-SSCL with different emission wavelengths across the visible spectrum. The CP-SSCL are characterized by a large absorption coefficient and high quantum yield, indicating that they exhibit the required high fluorescence brightness for cellular imaging application. In addition, the CP-SSCL also exhibit a high colloidal stability and low cytotoxicity. The in vitro studies of using MDA-MB-231 breast cancer cells show that the CP-SSCL are successfully uptaken by the cancer cells and located at the cytoplasm of the cells. Furthermore, by conjugating folic acid on their surfaces, the uptake of CP-SSCL by MDA-MB-231 cells was enhanced significantly, suggesting their great potential for targeted imaging and early detection of cancer cells.

  5. Fabrication and morphology of spongelike polymer material based on cross-linked sulfonated polystyrene particles.

    Science.gov (United States)

    Ji, Xiang; Wang, Mozhen; Xu, Dezhi; Ge, Xuewu; Liu, Huarong; Tang, Tao

    2012-04-03

    A novel spongelike polymer material has been fabricated by γ-ray induced polymerization of methylmethacrylate (MMA) in an emulsion containing cross-linked sulfonated polystyrene (CSP) particles. Scanning electron microscopy (SEM) images reveal that the spongelike structure is made up of interlinked nanosized PMMA particles with micrometer-sized CSP-PMMA particles embedded inside. The nitrogen adsorption isotherm discloses that the spongelike material has a high specific surface area of 29 m(2)/g and a narrow pore size distribution of 60-120 nm. The formation mechanism is discussed in this paper, which indicates that the key steps to form the spongelike material include a Pickering emulsion stabilized by the CSP particles, followed by the swelling process of MMA into these particles. This approach offers a more convenient alternative to prepare polymeric spongelike material without any etching procedure.

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

    Science.gov (United States)

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

    2001-03-08

    The electrical and optical properties of conjugated polymers have received considerable attention in the context of potentially low-cost replacements for conventional metals and inorganic semiconductors. Charge transport in these organic materials has been characterized in both the doped-metallic and the semiconducting state, but superconductivity has not hitherto been observed in these polymers. Here we report a distinct metal-insulator transition and metallic levels of conductivity in a polymer field-effect transistor. The active material is solution-cast regioregular poly(3-hexylthiophene), which forms relatively well ordered films owing to self-organization, and which yields a high charge carrier mobility (0.05-0.1 cm2 V(-1) s(-1)) at room temperature. At temperatures below approximately 2.35 K with sheet carrier densities exceeding 2.5 x 10(14) cm(-2), the polythiophene film becomes superconducting. The appearance of superconductivity seems to be closely related to the self-assembly properties of the polymer, as the introduction of additional disorder is found to suppress superconductivity. Our findings therefore demonstrate the feasibility of tuning the electrical properties of conjugated polymers over the largest range possible-from insulating to superconducting.

  7. Coarse-graining polymer solutions: A critical appraisal of single- and multi-site models

    Science.gov (United States)

    D'Adamo, G.; Menichetti, R.; Pelissetto, A.; Pierleoni, C.

    2015-09-01

    We critically discuss and review the general ideas behind single- and multi-site coarse-grained (CG) models as applied to macromolecular solutions in the dilute and semi-dilute regime. We first consider single-site models with zero-density and density-dependent pair potentials. We highlight advantages and limitations of each option in reproducing the thermodynamic behavior and the large-scale structure of the underlying reference model. As a case study we consider solutions of linear homopolymers in a solvent of variable quality. Secondly, we extend the discussion to multi-component systems presenting, as a test case, results for mixtures of colloids and polymers. Specifically, we found the CG model with zero-density potentials to be unable to predict fluid-fluid demixing in a reasonable range of densities for mixtures of colloids and polymers of equal size. For larger colloids, the polymer volume fractions at which phase separation occurs are largely overestimated. CG models with density-dependent potentials are somewhat less accurate than models with zero-density potentials in reproducing the thermodynamics of the system and, although they present a phase separation, they significantly underestimate the polymer volume fractions along the binodal. Finally, we discuss a general multi-site strategy, which is thermodynamically consistent and fully transferable with the number of sites, and that allows us to overcome most of the limitations discussed for single-site models.

  8. Polymer dynamics in semidilute solution during electrospinning: A simple model and experimental observations

    Science.gov (United States)

    Greenfeld, Israel; Arinstein, Arkadii; Fezzaa, Kamel; Rafailovich, Miriam H.; Zussman, Eyal

    2011-10-01

    Electrospun polymer nanofibers demonstrate outstanding mechanical and thermodynamic properties as compared to macroscopic-scale structures. Our previous work has demonstrated that these features are attributed to nanofiber microstructure [Nat. Nanotechnol.1748-338710.1038/nnano.2006.172 2, 59 (2007)]. It is clear that this microstructure is formed during the electrospinning process, characterized by a high stretching rate and rapid evaporation. Thus, when studying microstructure formation, its fast evolution must be taken into account. This study focuses on the dynamics of a highly entangled semidilute polymer solution under extreme longitudinal acceleration. The theoretical modeling predicts substantial longitudinal stretching and transversal contraction of the polymer network caused by the jet hydrodynamic forces, transforming the network to an almost fully stretched state. This prediction was verified by x-ray phase-contrast imaging of electrospinning jets of poly(ethylene oxide) and poly(methyl methacrylate) semidilute solutions, which revealed a noticeable increase in polymer concentration at the jet center, within less than 1 mm from the jet start. Thus, the proposed mechanism is applicable to the initial stage of the microstructure formation.

  9. New developments in polymer-controlled, bioinspired calcium phosphate mineralization from aqueous solution.

    Science.gov (United States)

    Bleek, Katrin; Taubert, Andreas

    2013-05-01

    The polymer-controlled and bioinspired precipitation of inorganic minerals from aqueous solution at near-ambient or physiological conditions avoiding high temperatures or organic solvents is a key research area in materials science. Polymer-controlled mineralization has been studied as a model for biomineralization and for the synthesis of (bioinspired and biocompatible) hybrid materials for a virtually unlimited number of applications. Calcium phosphate mineralization is of particular interest for bone and dental repair. Numerous studies have therefore addressed the mineralization of calcium phosphate using a wide variety of low- and high-molecular-weight additives. In spite of the growing interest and increasing number of experimental and theoretical data, the mechanisms of polymer-controlled calcium phosphate mineralization are not entirely clear to date, although the field has made significant progress in the last years. A set of elegant experiments and calculations has shed light on some details of mineral formation, but it is currently not possible to preprogram a mineralization reaction to yield a desired product for a specific application. The current article therefore summarizes and discusses the influence of (macro)molecular entities such as polymers, peptides, proteins and gels on biomimetic calcium phosphate mineralization from aqueous solution. It focuses on strategies to tune the kinetics, morphologies, final dimensions and crystal phases of calcium phosphate, as well as on mechanistic considerations.

  10. Polymer-Controlled Growth of CuO Nanodiscs in the Mild Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    PENG Yin; LIU Zhengyin; YANG Zihui

    2009-01-01

    CuO nanodiscs have been synthesized on a large scale by a facile solution-based method using polymers as crystal growth modifiers. X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and high resolu-tion transmission electron microscopy (HRTEM) were carded out to characterize the structures and morphologies of the obtained products. The effects of reaction temperature, concentrations of polyacrylamide (PAM) and reac-tants on the morphology and size of the product were studied. The results revealed that the CuO nanodisc had sin-gle-crystal monoclinic structures, and grew along (002) and (110) planes. Experimental conditions had all influence on the shape and size of the final products, but polymer PAM played the key role in formation of the CuO nanodisc.A possible growth mechanism of the CuO nanostructures based on typical polymer-crystal interactions in a mild aqueous solution was given. Polymer-directed crystal growth may provide promising routes to rational synthesis of various ordered inorganic and inorganic-organic hybrid materials with complex forms and structural specialization.

  11. Solution processed organic light-emitting diodes using the plasma cross-linking technology

    Science.gov (United States)

    He, Kongduo; Liu, Yang; Gong, Junyi; Zeng, Pan; Kong, Xun; Yang, Xilu; Yang, Cheng; Yu, Yan; Liang, Rongqing; Ou, Qiongrong

    2016-09-01

    Solution processed multilayer organic light-emitting diodes (OLEDs) present challenges, especially regarding dissolution of the first layer during deposition of a second layer. In this work, we first demonstrated a plasma cross-linking technology to produce a solution processed OLED. The surfaces of organic films can be cross-linked after mixed acetylene and Ar plasma treatment for several tens of seconds and resist corrosion of organic solvent. The film thickness and surface morphology of emissive layers (EMLs) with plasma treatment and subsequently spin-rinsed with chlorobenzene are nearly unchanged. The solution processed triple-layer OLED is successfully fabricated and the current efficiency increases 50% than that of the double-layer OLED. Fluorescent characteristics of EMLs are also observed to investigate factors influencing the efficiency of the triple-layer OLED. Plasma cross-linking technology may open up a new pathway towards fabrication of all-solution processed multilayer OLEDs and other soft electronic devices.

  12. Jacket-free stir bar sorptive extraction with bio-inspired polydopamine-functionalized immobilization of cross-linked polymer on stainless steel wire.

    Science.gov (United States)

    Zhang, Zixin; Zhang, Wenpeng; Bao, Tao; Chen, Zilin

    2015-08-14

    Stainless steel wire (SSW) is a good substrate for stir bar sorptive extraction (SBSE). However, it is still a challenge to immobilize commonly used cross-linked polymers onto SSW. In this work, we present a new approach for immobilization of the cross-linked organic polymer onto SSW for jacket-free SBSE. A dopamine derivative was firstly synthesized; by introducing a mussel-inspired polydopamine process, a stable coating layer was finally generated on the surface of SSW. Secondly, the cross-linked polymer was synthesized on the polydopamine-modified SSW by using acetonitrile as the porogen, acrylamide (AA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker and 2,2'-azobis (2-methylpropionitrile) as the initiator. A diluted pre-polymerization solution was carefully prepared to generate a thin layer of the polymer. The prepared poly(EGDMA-AA)-modified stir bar showed high stability and good tolerance toward stirring, ultrasonication, organic solvents, and strong acidic and basic conditions. Morphology and structure characterization of coatings were performed by scanning electron microscopy and Fourier transform infrared spectra, respectively. The prepared poly(EGDMA-AA)-modified stir bar showed great extraction efficiency toward protoberberines, with enrichment factors of 19-42. An SBSE-HPLC method was also developed for quantitative analysis of protoberberines. The method showed low limits of detection (0.06-0.15 ng mL(-1)), wide linear range (0.5-400 ng mL(-1)), good linearity (R≥0.9980) and good reproducibility (RSD≤3.60% for intra-day, RSD≤4.73% for inter-day). The developed method has been successfully applied to determine protoberberines in herb and rat plasma samples, with recoveries of 88.53-114.61%. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Polymer Conformation near the Critical Demixing Point of a Binary Solution

    Science.gov (United States)

    He, Lilin; Cheng, Gang; Melnichenko, Yuri

    2012-02-01

    We have used Contrast Matching Small Angle Neutron Scattering (CMSANS) to probe directly the conformation change of polyethylene glycerol (PEO) chains in the critical demixing region of Acetonitrile-d3 in (D2O + H2O) at concentration of the components corresponding to zero-average contrast condition. The d-PEO and h-PEO were mixed to match the scattering length density (SLD) of the critical liquid solution, which allowed us to extract single-chain dimension of polymer molecules in the aggregates near the critical point of the solvent. A non-monotonic variation of Rg was detected as temperature approached the critical temperature of phase demixing of acetonitrile- water solution, which was attributed to the interaction asymmetry of the solvent molecules with polymers predicted by Brochard and de Gennes two decades ago. To our best knowledge, this is the first direct experimental evidence supporting this prediction.

  14. Correlation between thermal diffusion and solvent self-diffusion in semidilute and concentrated polymer solutions.

    Science.gov (United States)

    Rauch, J; Hartung, M; Privalov, A F; Köhler, W

    2007-06-07

    We have performed measurements of thermal diffusion coefficients DT and solvent self-diffusion coefficients Dss in semidilute to concentrated polymer solutions. Solutes of different glass transition temperatures and solvents of different solvent qualities have been used. The investigated systems are in detail: poly(dimethyl-siloxane) in toluene, tristyrene in toluene, polystyrene in toluene, polystyrene in tetrahydrofuran, polystyrene in benzene, and polystyrene in cyclohexane. The thermal diffusion data are compared to our data and literature data for solvent self-diffusion coefficients. In all systems the concentration dependence of DT closely parallels the one of Dss which may be viewed as a local probe for friction on a length scale of the size of one polymer segment. This identifies local friction as the dominating parameter determining the concentration dependence of DT. Solvent quality, in contrast, has no influence on DT.

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

    Energy Technology Data Exchange (ETDEWEB)

    Minelli, Matteo; Doghieri, Ferruccio [Dipartimento di Ingegneria Civile, Chimica, Ambientale e dei Materiali (DICAM), Centro Interdipartimentale per la Ricerca Industriale - Meccanica Avanzata e Materiali (CIRI-MAM), Alma Mater Studiorum - Università di Bologna, via Terracini 28 - (Italy)

    2014-05-15

    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.

  16. Efficient inverted tandem polymer solar cells with a solution-processed recombination layer

    Energy Technology Data Exchange (ETDEWEB)

    Kouijzer, Sandra; Esiner, Serkan; Frijters, Corne H.; Wienk, Martijn M.; Janssen, Rene A.J. [Molecular Materials and Nanosystems, Eindhoven University of Technology (Netherlands); Turbiez, Mathieu [BASF Schweiz AG, Basel (Switzerland)

    2012-08-15

    Solution-processed tandem polymer solar cells with an inverted polarity configuration provide a power conversion efficiency of 5.8%. The tandem cells use an almost loss-free recombination layer and two photoactive layers, with wide and small bandgaps, to increase the power conversion efficiency beyond that of the corresponding single-layer cells. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Impact of Polymer Conformation on the Crystal Growth Inhibition of a Poorly Water-Soluble Drug in Aqueous Solution

    OpenAIRE

    Schram, Caitlin J.; Beaudoin, Stephen P.; Taylor, Lynne S.

    2014-01-01

    Poor aqueous solubility is a major hindrance to oral delivery of many emerging drugs. Supersaturated drug solutions can improve passive absorption across the gastrointestinal tract membrane as long as crystallization can be inhibited, enhancing the delivery of such poorly soluble therapeutics. Polymers can inhibit crystallization and prolong supersaturation; therefore, it is desirable to understand the attributes which render a polymer effective. In this study, the conformation of a polymer a...

  18. Radiation chemical studies on thermosensitive N-isopropylacrylamide and its polymer in aqueous solutions.

    Science.gov (United States)

    Acharya, Anjali; Mohan, Hari; Sabharwal, S

    2003-12-01

    The pulse radiolysis technique has been employed to determine the initiation and propagation rates of different transient species involved in the polymerization of N-isopropylacrylamide (NIPA) in aqueous solutions. Polymerization by anionic mechanism has been observed to be faster than by the free-radical mechanism. The kinetic, spectroscopic and redox properties of the transient species formed upon reaction of primary radiolytic species of water radiolysis with NIPA have been evaluated. The one-electron oxidation potential for the formation of a radical cation is quite high (>2 V), but the one-electron reduction potential is low (in the range of -0.3 to -0.7 V). The radical anion of NIPA is able to undergo an electron-transfer reaction with MV(2+), and has a pK(a) value of 3.2. The tert-butyl alcohol radical was also able to initiate polymerization. Gamma radiation-induced polymerization studies showed that the reaction of H(.)/(.)OH/e(aq)(-)/tert-butyl alcohol radicals with NIPA results in a nearly equal yield of the gel fraction. The hydrogel is observed to have very little swelling below pH 3 and above pH 10. The linear polymer of NIPA formed by irradiating dilute aqueous solution is found to be a thermosensitive polymer with lower a critical solution temperature (LCST) of ~33 degrees C. The diameters of polymer molecules were 290 and 20 nm at temperature below and above LCST, respectively.

  19. Dynamics of associative polymer solutions: Capillary break-up, jetting and rheology

    Science.gov (United States)

    Sharma, Vivek; Serdy, James G.; Threfall-Holmes, Phil; McKinley, Gareth H.

    2011-11-01

    Associative polymer solutions are used in extensively in the formulations for water-borne paints, food, inks, cosmetics, etc to control the rheology and processing behavior of multi-component dispersions. These complex dispersions are processed and used over a broad range of shear and extensional rates. Furthermore, the commercially relevant formulations use dilute solutions of associative polymers, which have low viscosity and short relaxation times, and hence their non-Newtonian response is not apparent in a conventional rheometer. In this talk, we explore several methods for systematically exploring the linear and nonlinear solution rheology of associative polymer dispersions, including: fractional model description of physical gelation, high frequency oscillatory tests at frequencies up to 10 kHz, microfluidic shear rheometry at deformation rates up to 1000000 /s and the influence of transient extensional rheology in the jet breakup. We show that high deformation rates can be obtained in jetting flows, and the growth and evolution of instability during jetting and break-up of these viscoelastic fluids shows the influence of both elasticity and extensibility.

  20. Solution-based single molecule imaging of surface-immobilized conjugated polymers.

    Science.gov (United States)

    Dalgarno, Paul A; Traina, Christopher A; Penedo, J Carlos; Bazan, Guillermo C; Samuel, Ifor D W

    2013-05-15

    The photophysical behavior of conjugated polymers used in modern optoelectronic devices is strongly influenced by their structural dynamics and conformational heterogeneity, both of which are dependent on solvent properties. Single molecule studies of these polymer systems embedded in a host matrix have proven to be very powerful to investigate the fundamental fluorescent properties. However, such studies lack the possibility of examining the relationship between conformational dynamics and photophysical response in solution, which is the phase from which films for devices are deposited. By developing a synthetic strategy to incorporate a biotin moiety as a surface attachment point at one end of a polyalkylthiophene, we immobilize it, enabling us to make the first single molecule fluorescence measurements of conjugated polymers for long periods of time in solution. We identify fluctuation patterns in the fluorescence signal that can be rationalized in terms of photobleaching and stochastic transitions to reversible dark states. Moreover, by using the advantages of solution-based imaging, we demonstrate that the addition of oxygen scavengers improves optical stability by significantly decreasing the photobleaching rates.

  1. Exceptionally stable polymer electrolyte for a lithium battery based on cross-linking by a residue-free process

    Science.gov (United States)

    Daigle, Jean-Christophe; Asakawa, Yuichiro; Vijh, Ashok; Hovington, Pierre; Armand, Michel; Zaghib, Karim

    2016-11-01

    In this paper, we report the synthesis of cross-linked copolymers of glycidyl methacrylate (GMA) and poly (ethylene glycol) methyl methacrylate (PEGMA) for use as solid polymer electrolytes (SPE). The cross-linking is performed with volatile ethylene diamine, thus preventing the accumulation of undesirable precursors in the final membrane. The structure of the cross-linked polymer electrolyte was investigated by 13C solid NMR and its physical properties were examined by DSC, TGA and stress-strain tests. The ionic conductivities were determined by AC Impedance, which showed that the SPEs have good conductivities (10-5 Scm-1) at 80 °C. The highest capacity measured with these polymers was 151 mAh g-1 at C/6 and 80 °C for a LFP/SPE/Lithium battery. The retention capacity is high, at 97% after 80 cycles at different rates of cycling. The Young's modulus of the membranes is as high as 1 GPa. The SEM images showed no evidence of lithium dendrites and no degradation after cycling. Therefore, the polymer is a good candidate for battery operation over a long time. Especially important is the ability of this polymer to prevent growth of dendrites on the Li-metal electrode.

  2. 5 GHz 200 Mbit/s radio over polymer fibre link with envelope detection at 650 nm wavelength

    DEFF Research Database (Denmark)

    Caballero Jambrina, Antonio; Jensen, Jesper Bevensee; Yu, Xianbin;

    2008-01-01

    All-optical envelope detection of a 5 GHz 200 Mbit/s modulated radio frequency signal is achieved using a 650 nm resonant cavity light emitting diode. Error-free transmission is achieved over a 50 m-long link of 1 mm diameter graded index polymer optical fibre (POF). The presented system has...... potential applications in low cost and low complexity short range wireless and wireline POF-based transmission links....

  3. AN INTERMOLECULAR 13C{1H} NUCLEAR OVERHAUSER EFFECT FOR THE CARBON OF CCl4 IN POLYMER SOLUTIONS

    Institute of Scientific and Technical Information of China (English)

    YAN Xin; WANG Dehua; QIAN Baogong

    1991-01-01

    An intermolecular 13C{1H} NOE of CCl4 in the solutions of polystyrene and polybutadiene and their copolymers was observed. The results show that the defined polymer-CCl4 interaction variable has a linear relation with the polymer composition and the difference of solubility parameters and exponentially depends on the reciprocal of temperature.

  4. 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

  5. Continuum theory of critical phenomena in polymer solutions: Formalism and mean field approximation

    Science.gov (United States)

    Goldstein, Raymond E.; Cherayil, Binny J.

    1989-06-01

    A theoretical description of the critical point of a polymer solution is formulated directly from the Edwards continuum model of polymers with two- and three-body excluded-volume interactions. A Hubbard-Stratonovich transformation analogous to that used in recent work on the liquid-vapor critical point of simple fluids is used to recast the grand partition function of the polymer solution as a functional integral over continuous fields. The resulting Landau-Ginzburg-Wilson (LGW) Hamiltonian is of the form of a generalized nonsymmetric n=1 component vector model, with operators directly related to certain connected correlation functions of a reference system. The latter is taken to be an ensemble of Gaussian chains with three-body excluded-volume repulsions, and the operators are computed in three dimensions by means of a perturbation theory that is rapidly convergent for long chains. A mean field theory of the functional integral yields a description of the critical point in which the power-law variations of the critical polymer volume fraction φc, critical temperature Tc, and critical amplitudes on polymerization index N are essentially identical to those found in the Flory-Huggins theory. In particular, we find φc ˜N-1/2, Tθ-Tc˜N-1/2 with (Tθ the theta temperature), and that the composition difference between coexisting phases varies with reduced temperature t as N-1/4t1/2. The mean field theory of the interfacial tension σ between coexisting phases near the critical point, developed by considering the LGW Hamiltonian for a weakly inhomogeneous solution, yields σ˜N-1/4t3/2, with the correlation length diverging as ξ˜N1/4t-1/2 within the same approximation, consistent with the mean field limit of de Gennes' scaling form. Generalizations to polydisperse systems are discussed.

  6. 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.

  7. 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.

  8. Shear Rheology of Suspensions of Porous Zeolite Particles in Concentrated Polymer Solutions

    Science.gov (United States)

    Olanrewaju, Kayode O.; Breedveld, Victor

    2008-07-01

    We present experimental data on the shear rheology of Ultem (polyetherimide)/NMP(l-methyl-2-pyrrolidinone) solutions with and without suspended surface-modified porous/nonporous zeolite (ZSM-5) particles. We found that the porous zeolite suspensions have relative viscosities that significantly exceed the Krieger-Dougherty predictions for hard sphere suspensions. The major origin of this discrepancy is the selective absorption of NMP solvent into the zeolite pores, which raises both the polymer concentration and the particle volume fraction, thus enhancing both the viscosity of the continuous phase Ultem/NMP polymer solution and the particle contribution to the suspension viscosity. Other factors, such as zeolite non-sphericity and specific interactions with Ultem polymer, contribute to the suspension viscosity to a lesser extent. We propose a predictive model for the viscosity of porous zeolite suspensions by incorporating an absorption parameter, α, into the Krieger-Dougherty model. We also propose independent approaches to determine α. The first one is indirect and based on zeolite density/porosity data, assuming that all pores will be filled with solvent. The other method is based on our experimental data, by comparing the viscosity data of porous versus non-porous zeolite suspensions. The different approaches are compared.

  9. Solution-Processed p-Dopant as Interlayer in Polymer Solar Cells.

    Science.gov (United States)

    Guillain, F; Endres, J; Bourgeois, L; Kahn, A; Vignau, L; Wantz, G

    2016-04-13

    We report here an original approach to dope the semiconducting polymer-metal interface in an inverted bulk-heterojunction (BHJ) organic solar cell. Solution-processed 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), is deposited on top of a P3HT:PC61BM layer before deposition of the top electrode. Doping of P3HT by F4-TCNQ occurs after thermally induced diffusion at 100 °C of the latter into the BHJ. Diffusion and doping are evidenced by XPS and UV-vis-NIR absorption. XPS highlights the decrease in Fluorine concentration on top of the BHJ after annealing. In the same time, a charge transfer band attributed to doping is observed in the UV-vis-NIR absorption spectrum. Inverted polymer solar cells using solution-processed F4-TCNQ exhibit power conversion efficiency of nearly 3.5% after annealing. This simple and efficient approach, together with the low annealing temperature required to allow diffusion and doping, leads to standard efficiency P3HT:PC61BM polymer solar cells, which are suitable for printing on plastic flexible substrate.

  10. Physically Cross-linked Polymer Binder Induced by Reversible Acid-Base Interaction for High-Performance Silicon Composite Anodes.

    Science.gov (United States)

    Lim, Sanghyun; Chu, Hodong; Lee, Kukjoo; Yim, Taeeun; Kim, Young-Jun; Mun, Junyoung; Kim, Tae-Hyun

    2015-10-28

    Silicon is greatly promising for high-capacity anode materials in lithium-ion batteries (LIBs) due to their exceptionally high theoretical capacity. However, it has a big challenge of severe volume changes during charge and discharge, resulting in substantial deterioration of the electrode and restricting its practical application. This conflict requires a novel binder system enabling reliable cyclability to hold silicon particles without severe disintegration of the electrode. Here, a physically cross-linked polymer binder induced by reversible acid-base interaction is reported for high performance silicon-anodes. Chemical cross-linking of polymer binders, mainly based on acidic polymers including poly(acrylic acid) (PAA), have been suggested as effective ways to accommodate the volume expansion of Si-based electrodes. Unlike the common chemical cross-linking, which causes a gradual and nonreversible fracturing of the cross-linked network, a physically cross-linked binder based on PAA-PBI (poly(benzimidazole)) efficiently holds the Si particles even after the large volume changes due to its ability to reversibly reconstruct ionic bonds. The PBI-containing binder, PAA-PBI-2, exhibited large capacity (1376.7 mAh g(-1)), high Coulombic efficiency (99.1%) and excellent cyclability (751.0 mAh g(-1) after 100 cycles). This simple yet efficient method is promising to solve the failures relating with pulverization and isolation from the severe volume changes of the Si electrode, and advance the realization of high-capacity LIBs.

  11. Insight into the crystallization of amorphous imine-linked polymer networks to 2D covalent organic frameworks.

    Science.gov (United States)

    Smith, Brian J; Overholts, Anna C; Hwang, Nicky; Dichtel, William R

    2016-03-04

    We explore the crystallization of a high surface area imine-linked two-dimensional covalent organic framework (2D COF). The growth process reveals rapid initial formation of an amorphous network that subsequently crystallizes into the layered 2D network. The metastable amorphous polymer may be isolated and resubjected to growth conditions to form the COF. These experiments provide the first mechanistic insight into the mechanism of imine-linked 2D COF formation, which is distinct from that of boronate-ester linked COFs.

  12. Polymer supported synthesis of novel benzoxazole linked benzimidazoles under microwave conditions: in vitro evaluation of VEGFR-3 kinase inhibition activity.

    Science.gov (United States)

    Chanda, Kaushik; Maiti, Barnali; Yellol, Gorakh S; Chien, Ming-Hsien; Kuo, Min-Liang; Sun, Chung-Ming

    2011-03-21

    An efficient soluble polymer-supported method has been developed for the parallel synthesis of substituted benzimidazole linked benzoxazoles using focused microwave irradiation. The key step involves the amidation of 4-hydroxy-3-nitrobenzoic acid with polymer-immobilized o-phenylenediamine. Application of mild acidic conditions promoted the ring closure to furnish the benzimidazole ring. After hydrogenation of the nitro-group to amine, the resulted polymer conjugates underwent efficient ring closure with various alkyl, aryl and heteroaryl isothiocyanates to generate the polymer-bound benzimidazolyl benzoxazoles. The polymer-bound compounds were finally cleaved from the support to furnish benzimidazole linked benzoxazole derivatives. The efficacy of the resultant angular bis-heterocyclic library was studied against vascular endothelial growth factor receptor (VEGFR-3). The preliminary screening of these novel compounds exhibits moderate to high inhibition (IC(50) = 0.56-1.42 μM). This protocol provides an easy access to novel angular bis-heterocycles which have potential for the discovery of novel leads for targeted cancer therapeutics.

  13. Correlation of inhibitory effects of polymers on indomethacin precipitation in solution and amorphous solid crystallization based on molecular interaction.

    Science.gov (United States)

    Chauhan, Harsh; Kuldipkumar, Anuj; Barder, Timothy; Medek, Ales; Gu, Chong-Hui; Atef, Eman

    2014-02-01

    To correlate the polymer's degree of precipitation inhibition of indomethacin in solution to the amorphous stabilization in solid state. Precipitation of indomethacin (IMC) in presence of polymers was continuously monitored by a UV spectrophotometer. Precipitates were characterized by PXRD, IR and SEM. Solid dispersions with different polymer to drug ratios were prepared using solvent evaporation. Crystallization of the solid dispersion was monitored using PXRD. Modulated differential scanning calorimetry (MDSC), IR, Raman and solid state NMR were used to explore the possible interactions between IMC and polymers. PVP K90, HPMC and Eudragit E100 showed precipitation inhibitory effects in solution whereas Eudragit L100, Eudragit S100 and PEG 8000 showed no effect on IMC precipitation. The rank order of precipitation inhibitory effect on IMC was found to be PVP K90 > Eudragit E100 > HPMC. In the solid state, polymers showing precipitation inhibitory effect also exhibited amorphous stabilization of IMC with the same rank order of effectiveness. IR, Raman and solid state NMR studies showed that rank order of crystallization inhibition correlates with strength of molecular interaction between IMC and polymers. Correlation is observed in the polymers ability to inhibit precipitation in solution and amorphous stabilization in the solid state for IMC and can be explained by the strength of drug polymer interactions.

  14. Polymer-clay nanocomposites obtained by solution polymerization of vinyl benzyl triammonium chloride in the presence of advanced functionalized clay

    Indian Academy of Sciences (India)

    Raluca Ianchis; Dan Donescu; Ludmila Otilia Cinteza; Violeta Purcar; Cristina Lavinia Nistor; Critian Petcu; Cristian Andi Nicolae; Raluca Gabor; Silviu Preda

    2014-05-01

    Polymer-clay nanocomposites were synthesized by solution polymerization method using advanced functionalized clay and vinyl benzyl trimethyl ammonium chloride as monomer. First stage consisted in the silylation of a commercial organo-modified clay-Cl 20A using alkoxysilanes with different chain lengths. In the second step, the synthesis and characterization of polymer-nanocomposites were followed. To evaluate the clay functionalization process as well as the final polymer-clay products, thermogravimetric,X-ray diffraction, dynamic light scattering, Fourier transform infrared spectroscopy and three test liquid contact angles analyses were used. The loss of ammonium ions from commercial clay, the grafting degree, the lengths and the nature of alkyl chain influence the dispersion of the advanced modified clay into the polymer solution and, furthermore, the properties of the final polymer-clay nanocomposite film.

  15. Deviations from a simple Debye relaxation in aqueous solutions of differently flexible polyions induced by polymer concentration.

    Science.gov (United States)

    Cametti, C; Sennato, S; Truzzolillo, D

    2009-07-21

    The electrical conductivity of aqueous solutions of differently flexible polymers has been measured in the frequency range from 1 MHz to 2 GHz. This note evidences how the shape parameter alpha of the conductivity relaxation associated with the orientational polarization of the aqueous phase depends on the polymer concentration and, moreover, reflects the different concentration regimes of the polymer solution (dilute, semidilute entangled and nonentangled, and concentrated regimes). The relevance of this dependence, as far as the microscopic environment of water molecules is concerned, is briefly discussed.

  16. Linking Precursor Alterations to Nanoscale Structure and Optical Transparency in Polymer Assisted Fast-Rate Dip-Coating of Vanadium Oxide Thin Films

    Science.gov (United States)

    Glynn, Colm; Creedon, Donal; Geaney, Hugh; Armstrong, Eileen; Collins, Timothy; Morris, Michael A.; Dwyer, Colm O.'

    2015-06-01

    Solution processed metal oxide thin films are important for modern optoelectronic devices ranging from thin film transistors to photovoltaics and for functional optical coatings. Solution processed techniques such as dip-coating, allow thin films to be rapidly deposited over a large range of surfaces including curved, flexible or plastic substrates without extensive processing of comparative vapour or physical deposition methods. To increase the effectiveness and versatility of dip-coated thin films, alterations to commonly used precursors can be made that facilitate controlled thin film deposition. The effects of polymer assisted deposition and changes in solvent-alkoxide dilution on the morphology, structure, optoelectronic properties and crystallinity of vanadium pentoxide thin films was studied using a dip-coating method using a substrate withdrawal speed within the fast-rate draining regime. The formation of sub-100 nm thin films could be achieved rapidly from dilute alkoxide based precursor solutions with high optical transmission in the visible, linked to the phase and film structure. The effects of the polymer addition was shown to change the crystallized vanadium pentoxide thin films from a granular surface structure to a polycrystalline structure composed of a high density of smaller in-plane grains, resulting in a uniform surface morphology with lower thickness and roughness.

  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. 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.

  19. Molecular Dynamics Simulation of Cross-Linked Epoxy Polymers: the Effect of Force Field on the Estimation of Properties

    Directory of Open Access Journals (Sweden)

    B. Arab

    2013-03-01

    Full Text Available In this paper, the molecular dynamics method was used to calculate the physical and mechanical properties of the cross-linked epoxy polymer composed of diglycidyl ether of bisphenol-A (DGEBA as resin and diethylenetriamine (DETA as curing agent. Calculation of the properties was performed using the constant-strain (static approach. A series of independent simulations were carried out based on four widely used force fields; COMPASS, PCFF, UFF and Dreiding. Proper comparisons between the results and also with experimental observations were made to find the most suitable force field for molecular dynamics simulation of polymer materials.

  20. Telecare and Social Link Solution for Ambient Assisted Living Using a Robot Companion with Visiophony

    Science.gov (United States)

    Varène, Thibaut; Hillereau, Paul; Simonnet, Thierry

    An increasing number of people are in need of help at home (elderly, isolated and/or disabled persons; people with mild cognitive impairment). Several solutions can be considered to maintain a social link while providing tele-care to these people. Many proposals suggest the use of a robot acting as a companion. In this paper we will look at an environment constrained solution, its drawbacks (such as latency) and its advantages (flexibility, integration…). A key design choice is to control the robot using a unified Voice over Internet Protocol (VoIP) solution, while addressing bandwidth limitations, providing good communication quality and reducing transmission latency

  1. Microchip-based 3D-Cell Culture Using Polymer Nanofibers Generated by Solution Blow Spinning.

    Science.gov (United States)

    Chen, Chengpeng; Townsend, Alexandra D; Sell, Scott A; Martin, R Scott

    2017-06-14

    Polymer nano/micro fibers have found many applications including 3D cell culture and the creation of wound dressings. The fibers can be produced by a variety of techniques that include electrospinning, the primary disadvantage of which include the requirement for a high voltage supply (which may cause issues such as polymer denaturation) and lack of portability. More recently, solution blow spinning, where a high velocity sheath gas is used instead of high voltage, has been used to generate polymer fibers. In this work, we used blow spinning to create nano/microfibers for microchip-based 3D cell culture. First, we thoroughly investigated fiber generation from a 3D printed gas sheath device using two polymers that are amenable to cell culture (polycaprolactone, PCL and polystyrene, PS) as well as the parameters that can affect PCL and PS fiber quality. Using the 3D printed sheath device, it was found that the pressure of the sheath N2 and the concentration of polymer solutions determine if fibers can be produced as well as the resulting fiber morphology. In addition, we showed how these fibers can be used for 3D cell culture by directly depositing PCL fibers in petri dishes and well plates. It is shown the fibers have good compatibility with RAW 264.7 macrophages and the PCL fiber scaffold can be as thick as 178 ± 14 μm. PCL fibers created from solution blow spinning (with the 3D printed sheath device) were then integrated with a microfluidic device for the first time to fabricate a 3D cell culture scaffold with a flow component. After culturing and stimulating macrophages on the fluidic device, it was found that the integrated 3D fibrous scaffold is a better mimic of the extracellular matrix (as opposed to a flat, 2D substrate), with enhanced nitrite accumulation (product of nitric oxide release) from macrophages stimulated with lipopolysaccharide. PS fibers were also made and integrated in a microfluidic device for 3D culture of endothelial cells, which stayed

  2. Formation of enzyme polymer engineered structure for laccase and cross-linked laccase aggregates stabilization.

    Science.gov (United States)

    Hassani, Thanina; Ba, Sidy; Cabana, Hubert

    2013-01-01

    Laccase and laccase-based cross-linked enzyme aggregates (CLEAs) were stabilized through the formation of a surrounding polymeric network made of chitosan and 3-aminopropyltriethoxysilane. The thermoresistance of the resulting enzyme polymer engineered structures of laccase (EPES-lac) and CLEAs (EPES-CLEA) were more than 30 times higher than that of free laccase and CLEAs at pH 3 and 40 °C. The EPES showed higher residual activity than the unmodified biocatalysts against chaotropic salts (up to 10 times), EDTA (up to 5 times), methanol (up to 15 times) and acetone (up to 20 times). The Michaelis-Menten kinetic parameters revealed that the affinity for 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) has doubled for the EPES-lac and EPES CLEA compared to their unmodified forms. The EPES-lac structures acted optimally at pH 4 and their activity was nearly temperature-independent, while the laccase activity of EPES-CLEA was optimal at pH 4 and 60 °C. Globally, the EPES have shown significantly improved properties which make them attractive candidate for the development of laccase-based applications.

  3. Optimization of β-cyclodextrin cross-linked polymer for monitoring of quercetin

    Science.gov (United States)

    Zhu, Xiashi; Ping, Wenhui

    2014-11-01

    A novel method for the separation/analysis of quercetin was described, which was based on the investigation of the inclusion interactions of β-cyclodextrin cross-linked polymer (β-CDCP) with quercetin (Qu) and the adsorption behavior of Qu on β-CDCP. The inclusion interaction of β-CDCP with Qu was studied through FTIR, TGA and 13C NMR. Under the optimum conditions, the preconcentration factor of the proposed method was approximately 8.8, the β-CDCP could be used repeatedly for 30 times and offered better recovery. The linear range, limit of detection (LOD) and the relative standard deviation (RSD) was found to be 0.10-12.0 μg mL-1, 4.6 ng mL-1 and 3.10% (n = 3, c = 2.0 μg mL-1) respectively. This technique had been successfully applied to the determination of Qu in real samples.

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

    Science.gov (United States)

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

    2016-11-10

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

  5. Highly Stable and Porous Cross-Linked Polymers for Efficient Photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Zhigang; Wang, Cheng; deKrafft, Kathryn E.; Lin, Wenbin

    2011-02-23

    Porous cross-linked polymers (PCPs) with phosphorescent [Ru(bpy)₃]{sup 2+} and [Ir(ppy)₂(bpy)]{sup +} building blocks were obtained via octacarbonyldicobalt (Co₂(CO)₈)-catalyzed alkyne trimerization reactions. The resultant Ru- and Ir-PCPs exhibited high porosity with specific surface areas of 1348 and 1547 m²/g, respectively. They are thermally stable at up to 350 °C in air and do not dissolve or decompose in all solvents tested, including concentrated hydrochloric acid. The photoactive PCPs were shown to be highly effective, recyclable, and reusable heterogeneous photocatalysts for aza-Henry reactions, α-arylation of bromomalonate, and oxyamination of an aldehyde, with catalytic activities comparable to those of the homogeneous [Ru(bpy)₃]{sup 2+} and [Ir(ppy)₂(bpy)]{sup +} photocatalysts. This work highlights the potential of developing photoactive PCPs as highly stable, molecularly tunable, and recyclable and reusable heterogeneous photocatalysts for a variety of important organic transformations.

  6. 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.

  7. Removal of Chloroform from Hydrochloride Acid Solution Using Fine Powder of Polymer as Adsorbent

    Institute of Scientific and Technical Information of China (English)

    LU,Yingzhou; QUE,Yong; LI,Chunxi; MENG,Hong; WANG,Zihao

    2009-01-01

    In order to choose a suitable adsorbent for the removal of chloroform from its hydrochloric acid solution,the adsorptive ability of some polymer adsorbents was investigated in terms of their adsorption curves in water and 20% hydrochloric acid solutions at 298.15 K,and compared with that of active carbon (AC) and solid paraffin (SP).The adsorbents studied include the fine powders of chlorinated rubber (CR),polypropylene (PP),chlorinated polypropylene (CPP) and polyvinylchloride (PVC).The results showed that the adsorption behavior followed the Langmuir equation and the adsorption ability of these adsorbents followed the order AC > PVC > CR > PP > CPP> SP.This order is basically in line with the decrease of chloro-content of the adsorbents from PVC to SP.The adsorptivity of PVC and CR was nearly equivalent to that of AC with their saturated adsorption being about 1.4 g-CHCl3 (g-absorbent) -1.For all adsorbents studied,the adsorption capacity always decreases with the increase of hydrochloric acid concentration.It is showed that the commercial polymer powder of PVC or CR can be used as an efficient absorbent for the removal of chloroform from its aqueous solution for its low cost,good adsorption ability and ease of thermal desorption for recycling.

  8. Using Selected Chemical and Physical Factors to Cross-link a BioCo Polymer Binder - Mineral Matrix System

    Directory of Open Access Journals (Sweden)

    B. Grabowska

    2013-04-01

    Full Text Available This publication describes research on the course of the process of cross-linking new BioCo polymer binders - in the form of water-based polymer compositions of poly(acrylic acid or poly(sodium acrylate/modified polysaccharide - using selected physical and chemical factors. It has been shown that the type of cross-linking factor used influences the strength parameters of the moulding sand. The crosslinking factors selected during basic research make it possible to obtain sand strengths similar to those of samples of sands bonded with commercial binders. Microwave radiation turned out to be the most effective cross-linking factor in a binder-matrix system. It was proven that adsorption in the microwave radiation field leads to the formation of polymer lattices with hydrogen bonds which play a major role in maintaining the formed cross-linked structures in the binder-matrix system. As a result, the process improves the strength parameters of the sand, whereas the hardening process in a microwave field significantly shortens the setting time.

  9. Mannitol influence on the separation of DNA fragments by capillary electrophoresis in entangled polymer solutions.

    Science.gov (United States)

    Han, F; Xue, J; Lin, B

    1998-08-01

    A new kind of sieving matrix is presented in this paper to allow satisfactory separation of DNA fragments in a relatively low viscous solution. When a certain amount of mannitol was added to cellulose solution not concentrated enough to separate PGEM-3Zf(+)/HaeIII standards well, a polymer solution with low viscosity but with very good separation effects was obtained. The separation result of this sieving buffer was comparable with those using highly concentrated cellulose solutions. The sieving ability of solutions with different cellulose concentrations and different amounts of mannitol has been investigated. It was proved that 0.5% was the minimum hydroxypropylmethylcellulose (HPMC) concentration that could be used to separate DNA fragments satisfactorily. HPMC solutions with a concentration of less than 0.5% could not separate the standard DNA fragments even in the presence of mannitol. It was found that 6% was the optimized mannitol concentration because either more or less mannitol will lead a decrease of resolution. The principle of the positive influence of mannitol has also been discussed.

  10. 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

    2016-12-13

    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. To compare polymer-based oral rehydration solution (polymer-based ORS) with glucose-based oral rehydration solution (glucose-based ORS) for treating acute watery diarrhoea. 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. 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). 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. 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 (752 participants) evaluated this comparison, and seven trials used rice as a polymer source

  11. Thermoresponsive Polymers with Lower Critical Solution Temperature- or Upper Critical Solution Temperature-Type Phase Behaviour Do Not Induce Toxicity to Human Endothelial Cells.

    Science.gov (United States)

    Ji, Yuejia; Zhu, Mengxiang; Gong, Yu; Tang, Haoyu; Li, Juan; Cao, Yi

    2017-01-01

    Thermoresponsive polymers have gained extensive attention as biomedical materials especially for targeted drug delivery systems. We have recently developed water-soluble polypeptide-based thermoresponsive polymers that exhibit lower critical solution temperature (LCST)- or upper critical solution temperature (UCST)-type phase behaviours. In this study, the toxicity of these polymers to human umbilical vein endothelial cells (HUVECs) was investigated to assess the safety and biocompatibility. Up to 100 μg/ml, thermoresponsive polymers did not induce cytotoxicity to HUVECs, showing as unaltered mitochondrial viability assessed as cell counting kit-8 (CCK-8) assay and membrane integrity assessed as lactate dehydrogenase (LDH) assay. Inflammatory response, assessed as the release of chemokine-soluble monocyte chemotactic protein 1 (sMCP-1) and interleukin-8 (IL-8) as well as cytokine IL-6, was not significantly affected by the polymers. In addition, 1 μM thapsigargin (TG), an endoplasmic reticulum (ER) stress inducer, significantly decreased mitochondrial viability, but did not affect membrane integrity or inflammatory response. The presence of thermoresponsive polymers with LCST-type phase behaviour did not further affect the effects of TG. In conclusion, the thermoresponsive polymers used in this study are not toxic to endothelial cells and therefore could be further considered as safe materials for biomedical applications.

  12. Elastic effects of dilute polymer solution on bubble generation in a microfluidic flow-focusing channel

    Science.gov (United States)

    Kim, Dong Young; Shim, Tae Soup; Kim, Ju Min

    2017-05-01

    Recently, two-phase flow in microfluidics has attracted much attention because of its importance in generating droplets or bubbles that can be used as building blocks for material synthesis and biological applications. However, there are many unresolved issues in understanding droplet and bubble generation processes, especially when complex fluids are involved. In this study, we investigated elastic effects on bubble generation processes in a flow-focusing geometry and the shapes of the produced bubbles flowing through a microchannel. We used dilute polymer solutions with nearly constant shear viscosities so that the shear-thinning effects on bubble generation could be precluded. We observed that a very small amount of polymer (poly(ethylene oxide) at O(10) ppm) significantly affects bubble generation. When the polymer was added to a Newtonian fluid, the fluctuation in bubble size increased notably, which was attributed to the chaotic flow dynamics in the flow-focusing region. In addition, it was demonstrated that the bubbles were thinner along the minor axis in the viscoelastic fluid than they were in the Newtonian fluid. We expect that the current results will contribute to understanding the dynamics of two-phase flow in microchannels and the design and operation of the microfluidic devices to generate microbubbles.

  13. 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

    electrostatic attraction and form a protective layer. For example, polyacrylic acid (PAA) showed a reduction in coefficient of friction by ca. 28% and wear rate by 50% at a concentration of 10 mg/mL in PBS solution compared to polymer-free buffer solution. This effect was comparable to reported lubricating...

  14. Preparation of porous, chemically cross-linked, PVdF-based gel polymer electrolytes for rechargeable lithium batteries

    Science.gov (United States)

    Cheng, C. L.; Wan, C. C.; Wang, Y. Y.

    This study reports the development of a new system of porous, chemically cross-linked, gel polymer electrolytes based on poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) copolymer as a polymer matrix, polyethylene glycol (PEG) as a plasticizer, and polyethylene glycol dimethacrylate (PEGDMA) as a chemical cross-linking oligomer. The electrolytes are prepared by a combination of controlled evaporation and thermal polymerization of PEGDMA. PVdF-HFP/PEG/PEGDMA gel polymer electrolytes with a composition of 5/3/2 exhibit both high ambient ionic conductivity, viz., >1 mS cm -1, and a high tensile modulus of 52 MPa, because of their porous and network structures. All the blends of electrolytes are electrochemically stable up to 5 V versus Li/Li + in the presence of 1 M LiPF 6/ethylene carbonate-diethyl carbonate (EC-DEC). With these polymer electrolytes, rechargeable lithium batteries composed of carbon anode and LiCoO 2 cathode have acceptable cycleability and a good rate capability.

  15. Fabrication of conductive polymer nanofibers through SWNT supramolecular functionalization and aqueous solution processing

    Science.gov (United States)

    Naeem, Fahim; Prestayko, Rachel; Saem, Sokunthearath; Nowicki, Lauren; Imit, Mokhtar; Adronov, Alex; Moran-Mirabal, Jose M.

    2015-10-01

    Polymeric thin films and nanostructured composites with excellent electrical properties are required for the development of advanced optoelectronic devices, flexible electronics, wearable sensors, and tissue engineering scaffolds. Because most polymers available for fabrication are insulating, one of the biggest challenges remains the preparation of inexpensive polymer composites with good electrical conductivity. Among the nanomaterials used to enhance composite performance, single walled carbon nanotubes (SWNTs) are ideal due to their unique physical and electrical properties. Yet, a barrier to their widespread application is that they do not readily disperse in solvents traditionally used for polymer processing. In this study, we employed supramolecular functionalization of SWNTs with a conjugated polyelectrolyte as a simple approach to produce stable aqueous nanotube suspensions, that could be effortlessly blended with the polymer poly(ethyleneoxide) (PEO). The homogeneous SWNT:PEO mixtures were used to fabricate conductive thin films and nanofibers with improved conductivities through drop casting and electrospinning. The physical characterization of electrospun nanofibers through Raman spectroscopy and SEM revealed that the SWNTs were uniformly incorporated throughout the composites. The electrical characterization of SWNT:PEO thin films allowed us to assess their conductivity and establish a percolation threshold of 0.1 wt% SWNT. Similarly, measurement of the nanofiber conductivity showed that the electrospinning process improved the contact between nanotube complexes, resulting in conductivities in the S m-1 range with much lower weight loading of SWNTs than their thin film counterparts. The methods reported for the fabrication of conductive nanofibers are simple, inexpensive, and enable SWNT processing in aqueous solutions, and offer great potential for nanofiber use in applications involving flexible electronics, sensing devices, and tissue engineering

  16. Mixing and structural properties of model polymer solutions: Molecular theory and simulation

    Science.gov (United States)

    McDaniels, Brian S.

    1999-12-01

    Recent advances in new single-site catalysts continue to fuel an already growing polymer market. As the market increases, a better understanding of polymers becomes critical. The majority of this understanding has been acquired through experimentation. While important, experimentation may be expensive and time consuming. Thus, it is desirable to predict polymer properties from molecular level characteristics. While a large amount of work has been performed in the area of overall properties of pure and mixture fluids, little work has been done in the area of mixing properties. Our initial effort into this area includes investigating the ability of the compressible Flory, generalized Flory dimer, and interpolating equations of state to predict mixing properties of a model polymer system. In determining the accuracy of the equations, Monte Carlo simulations have been performed in the Gibbs ensemble. A problem in the simulation of these systems, limited access to sampling space, has occurred and an established remedy has been discussed. We have determined that the most effective solution to the problem is a combination of conventional moves and the established correction. Predictions of the overall pressure, osmotic pressure, activity coefficient and Flory Chi parameter have been compared with simulation results, good agreement occurs at high densities, long chain lengths, and high chain concentrations except for the compressible Flory equation of state which only provides qualitatively correct predictions for the mixing properties. The structure of the fluid also is discussed. An increase in the packing fraction results in chain contraction. The addition of a monomeric solvent causes solvation in low to medium packing fraction fluids. Because the addition of solvent increases the packing fraction, the chains also contract. The effect of increasing packing fraction is stronger than the addition of solvent. The monomeric solvent forms clusters over the range of

  17. Fabrication of conductive polymer nanofibers through SWNT supramolecular functionalization and aqueous solution processing.

    Science.gov (United States)

    Naeem, Fahim; Prestayko, Rachel; Saem, Sokunthearath; Nowicki, Lauren; Imit, Mokhtar; Adronov, Alex; Moran-Mirabal, Jose M

    2015-10-02

    Polymeric thin films and nanostructured composites with excellent electrical properties are required for the development of advanced optoelectronic devices, flexible electronics, wearable sensors, and tissue engineering scaffolds. Because most polymers available for fabrication are insulating, one of the biggest challenges remains the preparation of inexpensive polymer composites with good electrical conductivity. Among the nanomaterials used to enhance composite performance, single walled carbon nanotubes (SWNTs) are ideal due to their unique physical and electrical properties. Yet, a barrier to their widespread application is that they do not readily disperse in solvents traditionally used for polymer processing. In this study, we employed supramolecular functionalization of SWNTs with a conjugated polyelectrolyte as a simple approach to produce stable aqueous nanotube suspensions, that could be effortlessly blended with the polymer poly(ethyleneoxide) (PEO). The homogeneous SWNT:PEO mixtures were used to fabricate conductive thin films and nanofibers with improved conductivities through drop casting and electrospinning. The physical characterization of electrospun nanofibers through Raman spectroscopy and SEM revealed that the SWNTs were uniformly incorporated throughout the composites. The electrical characterization of SWNT:PEO thin films allowed us to assess their conductivity and establish a percolation threshold of 0.1 wt% SWNT. Similarly, measurement of the nanofiber conductivity showed that the electrospinning process improved the contact between nanotube complexes, resulting in conductivities in the S m(-1) range with much lower weight loading of SWNTs than their thin film counterparts. The methods reported for the fabrication of conductive nanofibers are simple, inexpensive, and enable SWNT processing in aqueous solutions, and offer great potential for nanofiber use in applications involving flexible electronics, sensing devices, and tissue engineering

  18. 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}.

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

    Science.gov (United States)

    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.

    2008-09-01

    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 Tc = 90 K as well as high Jc (0 T, 77 K) over 3 MA/cm 2.

  20. 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.

  1. Study of diffusion in polymer solutions and networks by fluorescence correlation spectroscopy

    Science.gov (United States)

    Chehreghanianzabi, Yasaman

    Diffusion in polymer solutions and networks is a topic of vast importance in many fields related to medical devices, tissue engineering, and drug delivery. Understanding diffusion in such environments is also essential for describing molecular transport through biological systems such as cells and tissues. Fluorescence correlation spectroscopy (FCS) is single molecule spectroscopic technique that measures the fluctuations of fluorescent probes in a defined confocal volume and correlates them in time to give information on diffusion times, concentrations, and interactions as well as indirectly, on macromolecular structure or conformation. In the first project we used diffusivity data obtained by FCS to develop a novel homogenization theory model to accurately predict solute diffusivity in polymer solutions. We focused on a setting where diffusivity was hindered by obstruction only. By choosing experimental conditions that satisfied the model assumptions, we were able to validate the homogenization theory model. While testing diffusivity in various polymer solutions, we also observed an unexpected phenomenon--a dramatic decrease in diffusivity of small fluorophores in dilute solutions of polyethylene glycol (PEG), which led to the second project. Here, we determined that the rapid drop was due to a complexation between the PEG and the fluorophore. We also determined that this complexation was highly specific and could be attributed to hydrogel bonding between the ether oxygen of PEG and the carboxylic hydrogen of the fluorophore. We then transitioned to a more complex hydrogel network environment, namely fluorophore diffusivity in various alginate hydrogels--varied by concentration and modifications with a cell adhesive ligand. Importantly, we were able to determine that while the fluorophore diffusivity was hindered due to electrostatic interactions, it was the same irrespective of the alginate concentration or modifications. The last part of this thesis was focused

  2. The corrosion effect of ozonated seawater solution on titanium in polymer generated crevice environments

    Energy Technology Data Exchange (ETDEWEB)

    Leveillee, S.Y.

    1998-01-01

    Two different tests were designed to evaluate the reaction of various polymers and grade-2 titanium in ozonated seawater in conjunction with a comparative analysis in an aerated seawater solution. The first was a weight loss test measuring the weight change of Polyvinyl chloride (PVC), Polyethylene and Teflon{trademark} in both ozonated and aerated artificial seawater baths. The second test was designed to induce crevice corrosion on the titanium test samples using various crevice generating materials in both ozonated and aerated solutions. The materials used to create the crevices were grade-2 titanium washers, PVC, Polyethylene, Saran and Teflon{trademark}. The weight loss test showed that all three polymers lost weight in the ozonated bath. The results of the titanium washer crevice test provided no indication of corrosion or surface discoloration in either the ozonated or aerated solutions. Energy dispersive spectrometry (EDS) analysis found no fluorine, chlorine or other corrosion product. The PVC samples in the aerated bath also showed no signs of corrosion, but the PVC samples in the ozonated tank had light brown rings of surface discoloration. One of the ozonated PVC samples did show evidence of chlorine in the corrosion product. The outer circumference of the ozonated PVC washers exhibited the same type bleaching effect as in the weight loss samples, but the whitening of these samples were more pronounced. The polyethylene samples under aeration showed no discoloration or presence of fluorine or chlorine. The polyethylene crevice samples in the ozonated solution all exhibited the distinct brilliant blue color of titanium oxide. Fluorine was found in the corrosion product on only one of the samples. Chlorine was found on the surface of one of the other corrosion coupons. The results of the Teflon{trademark} crevice samples substantiated the previous Rensselaer study.

  3. 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.

  4. Hydrodynamic effects on phase separation morphologies in evaporating thin films of polymer solutions

    Science.gov (United States)

    Zoumpouli, Garyfalia A.; Yiantsios, Stergios G.

    2016-08-01

    We examine effects of hydrodynamics on phase separation morphologies developed during drying of thin films containing a volatile solvent and two dissolved polymers. Cahn-Hilliard and Flory-Huggins theories are used to describe the free energy of the phase separating systems. The thin films, considered as Newtonian fluids, flow in response to Korteweg stresses arising due to concentration non-uniformities that develop during solvent evaporation. Numerical simulations are employed to investigate the effects of a Peclet number, defined in terms of system physical properties, as well as the effects of parameters characterizing the speed of evaporation and preferential wetting of the solutes at the gas interface. For systems exhibiting preferential wetting, diffusion alone is known to favor lamellar configurations for the separated phases in the dried film. However, a mechanism of hydrodynamic instability of a short length scale is revealed, which beyond a threshold Peclet number may deform and break the lamellae. The critical Peclet number tends to decrease as the evaporation rate increases and to increase with the tendency of the polymers to selectively wet the gas interface. As the Peclet number increases, the instability moves closer to the gas interface and induces the formation of a lateral segregation template that guides the subsequent evolution of the phase separation process. On the other hand, for systems with no preferential wetting or any other property asymmetries between the two polymers, diffusion alone favors the formation of laterally separated configurations. In this case, concentration perturbation modes that lead to enhanced Korteweg stresses may be favored for sufficiently large Peclet numbers. For such modes, a second mechanism is revealed, which is similar to the solutocapillary Marangoni instability observed in evaporating solutions when interfacial tension increases with the concentration of the non-volatile component. This mechanism may lead

  5. Viscoelastic rheological property of different types of polymer solutions for enhanced oil recovery

    Institute of Scientific and Technical Information of China (English)

    孟令伟; 康万利; 周阳; 王志伟; 刘述忍; 白宝君

    2008-01-01

    The capability of hydrophobic association polymer(HAPAM) to displace oil is different from that of hydrolyzed polyacrylamide(HPAM) because they have different rheological properties.The viscoelasticity of five polymers was measured using Physica MCR301 rheometer and was compared.The five polymers include three HAPAMs with relative molecular mass of 1 248×104(TypeⅠ),750×104(TypeⅡ),and 571×104(Type Ⅲ) separately and two HPAMs with relative molecular mass of 1 200×104 and 3 800×104 respectively.The experiment results indicate that the viscoelasticity of HAPAM is better than that of HPAM.The storage modulus G’ and the loss modulus G″ for HAPAM solutions are also larger than those for HPAM.Comparing the rheological curves of different HAPAM types,it is found that the viscosity of typeⅡ and type Ⅲ is almost same at different shear rates while the viscosity of type I is the lower than that of Types Ⅱ and Ⅲ.The storage modulus G’ and the loss modulus G″ for three types of HAPAM were measured in low oscillation frequency range,and the results show that G’ is greater than G″ for all three different types of HAPAM,but their loss modulus is almost same,and the G’ is in the order of type Ⅱ>type Ⅲ>type I.In addition,the G’ and G″ increase with aging time for all three HAPAM solutions were stayed at different days.The viscoelasticity of type Ⅰ reaches the highest value when aging time is 9 d at 45 ℃,but it is 7 d for type Ⅱ and type Ⅲ.The different viscoelasticity properties can be attributed to self-organization supermolecule networks which is formed by hydrophobic association of HAPAM molecular and molecular chain entanglement.

  6. Polymer fractionation

    Energy Technology Data Exchange (ETDEWEB)

    Hadermann, A. F.

    1985-04-09

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

  7. Nano Copper Powders Synthesized by a Polymer Solution Method at Low Temperature.

    Science.gov (United States)

    Han, Young-Min; Jung, Choong-Hwan; Lee, Sang-Jin

    2015-07-01

    Copper (Cu) nano particles were successfully fabricated at a significantly low temperature through a simple polymer solution route. In the process, the organic-inorganic precursor sols were turned to porous gels exhibiting volume expansion during the drying process. The PVA polymer, as an organic carrier, contributed to make an atom-scale homogeneous copper precursor gel, which resulted in fully crystallized, nano-sized copper powders through a low calcination temperature of 300 °C under Ar-4%H2 atmosphere. Variations in the processing technique, such as the content of PVA and calcination temperature, affected the microstructure and crystallization behavior of the synthesized powders. The copper powder synthesized with the PVA content of 4:1 ratio showed a crystallite size of about 10 nm or less with a high surface area. In this paper, the PVA solution technique for the fabrication of a nano-sized copper powder is introduced. The effects of the PVA content and calcination conditions on the powder morphology and crystallization are also studied. The characterization of the synthesized powders is conducted by using XRD, DTA/TG, SEM and TEM.

  8. Pore scale mixing and macroscopic solute dispersion regimes in polymer flows inside 2D model networks

    CERN Document Server

    D'Angelo, M V; Allain, C; Hulin, J P; Angelo, Maria Veronica D'; Auradou, Harold; Allain, Catherine; Hulin, Jean-Pierre

    2006-01-01

    A change of solute dispersion regime with the flow velocity has been studied both at the macroscopic and pore scales in a transparent array of capillary channels using an optical technique allowing for simultaneous local and global concentration mappings. Two solutions of different polymer concentrations (500 and 1000 ppm) have been used at different P\\'eclet numbers. At the macroscopic scale, the displacement front displays a diffusive spreading: for $Pe \\leq 10$, the dispersivity $l\\_d$ is constant with $Pe$ and increases with the polymer concentration; for $Pe > 10$, $l\\_d$ increases as $Pe^{1.35}$ and is similar for the two concentrations. At the local scale, a time lag between the saturations of channels parallel and perpendicular to the mean flow has been observed and studied as a function of the flow rate. These local measurements suggest that the change of dispersion regime is related to variations of the degree of mixing at the junctions. For $Pe \\leq 10$, complete mixing leads to pure geometrical di...

  9. 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.

  10. 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.

  11. 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.

  12. A SLOW RELAXATION MODE OF POLYMER CHAINS IN A SEMIDILUTE SOLUTION

    Institute of Scientific and Technical Information of China (English)

    Jun-fang Li; Yi-jie Lu; Guang-zhao Zhang; Wei Li; Chi Wu

    2008-01-01

    Dust-free semidilute and concentrated polystyrene (PS) solutions in different solvents were prepared by slow evaporation and in situ anionic polymerization, which removes the effects of troublesome artifacts such as dust contamination and concentration gradient. The dynamics was reexamined by a combination of static and dynamic laser light scattering. In benzene and toluene (good solvents for PS), only one fast diffusive mode of polymer chains can be observed when the concentration (c) is up to 20%, which is attributed to thermally agitated fluctuation of "blobs" or chain segments.Static and dynamic correlation lengths (ξS and ξD) are scaled with c as ξSS(or ξD)~c-0.72±0.02. In cyclohexane, whose quality decreases with temperature in the range 32-50℃, an additional slow mode of polymer chains can be observed. Such a slow mode is viewed more obviously at a large scattering angle even in a concentrated solution with high chain entanglement. The present study indicates that the slow mode is due to the solvent quality.

  13. Visualization of TCE recovery mechanisms using surfactant-polymer solutions in a two-dimensional heterogeneous sand model.

    Science.gov (United States)

    Robert, Thomas; Martel, Richard; Conrad, Stephen H; Lefebvre, René; Gabriel, Uta

    2006-06-30

    This research focused on the optimization of TCE dissolution in a physical two-dimensional model providing a realistic representation of a heterogeneous granular aquifer. TCE was infiltrated in the sand pack where it resided both in pools and in zones of residual saturation. Surfactant was initially injected at low concentration to minimize TCE remobilization at first contact but was incrementally increased later during the experiment. Xanthan gum was added to the injected surfactant solution to optimize the sweep efficiency through the heterogeneous medium. Photographs and digital image analysis illustrated the interactions between TCE and the injected fluids. During the polymer flood, the effects of heterogeneities inside the sand pack were greatly reduced by the increased fluid viscosity and the shear-thinning effects of the polymer. The polymer also improved the contact between the TCE ganglia and the surfactant-polymer solution, thereby promoting dissolution. Surfactants interacted with the polymer reducing the overall viscosity of the solution. At first contact with a 0.5%(mass) surfactant solution, the TCE pools drained and some remobilization occurred. However, no TCE bank was formed and TCE did not penetrate into any previously uncontaminated areas. As a result, TCE surface area was increased. Subsequent surfactant floods at higher surfactant concentrations did not trigger more remobilization. TCE was mainly dissolved by the solution with the highest surfactant concentration. Plugging from bacterial growth or microgel formation associated to the polymer at the inflow screen prevented the full completion of the experiment. However, more than 90% of TCE was recovered with the circulation of less than 6 pore volumes of surfactant-polymer solution.

  14. Simulation and theory of self-assembly and network formation in reversibly cross-linked equilibrium polymers

    Science.gov (United States)

    Kindt, James T.

    2005-10-01

    A simulation model of hard spheres capable of reversible assembly into chains, which then may reversibly cross-link into networks, has been studied through grand canonical Monte Carlo simulation. Effects of varying intra- and interchain bond strengths, chain flexibilities, and restrictions on cross-linking angle were investigated. Observations including chain-length distributions and phase separation could be captured in most cases using a simple model theory. The coupling of chain growth to cross-linking was shown to be highly sensitive to the treatment of cross-linking by chain ends. In some systems, ladderlike domains of several cross-links joining two chains were common, resulting from cooperativity in the cross-linking. Extended to account for this phenomenon, the model theory predicts that such cooperativity will suppress phase separation in weakly polymerizing chains and at high cross-link concentration. In the present model, cross-linking stabilizes the isotropic phase with respect to the nematic phase, causing a shift in the isotropic-nematic transition to higher monomer concentration than in simple equilibrium polymers.

  15. 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

  16. Liquid crystalline polymers IX Main chain thermotropic poly (azomethine – ethers containing thiazole moiety linked with polymethylene spacers

    Directory of Open Access Journals (Sweden)

    2007-04-01

    Full Text Available A new homologous series of thermally stable thermotropic liquid crystalline poly(azomethine-ethers based on thiazole moiety were synthesized by solution polycondensation of 4,4`-diformyl-α,ω-diphenoxyalkanes, I–IV or 4,4`-diformyl-2,2`-dimethoxy-α,ω-diphenoxyalkanes V–VIII with the new bis(2-aminothiazole monomer X. A model compound XI was synthesized from X with benzaldehyde and characterized by elemental and spectral analyses. The inherent viscosities of the resulting polymers were in the range 0.43–1.34 dI/g. All the poly(azomethine-ethers were insoluble in common organic solvents but dissolved completely in concentrated H2SO4 and formic acid. The mesomorphic properties of these polymers were studied as a function of the diphenoxyalkane space length. Their thermotropic liquid crystalline properties were examined by DSC and optical polarizing microscopy and demonstrated that the resulting polymers form nematic mesophases over wide temperature ranges. The thermogravimetric analyses of those polymers were evaluated by TGA and DSC measurements and correlated to their structural units. X-ray analysis showed that polymers having some degree of crystallinity in the region 2θ = 5–60°. In addition, the morphological properties of selected examples were tested by scanning electron microscopy.

  17. Post polymerization cure shape memory polymers

    Science.gov (United States)

    Wilson, Thomas S; Hearon, Michael Keith; Bearinger, Jane P

    2014-11-11

    This invention relates to chemical polymer compositions, methods of synthesis, and fabrication methods for devices regarding polymers capable of displaying shape memory behavior (SMPs) and which can first be polymerized to a linear or branched polymeric structure, having thermoplastic properties, subsequently processed into a device through processes typical of polymer melts, solutions, and dispersions and then crossed linked to a shape memory thermoset polymer retaining the processed shape.

  18. Post polymerization cure shape memory polymers

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Thomas S.; Hearon, II, Michael Keith; Bearinger, Jane P.

    2017-01-10

    This invention relates to chemical polymer compositions, methods of synthesis, and fabrication methods for devices regarding polymers capable of displaying shape memory behavior (SMPs) and which can first be polymerized to a linear or branched polymeric structure, having thermoplastic properties, subsequently processed into a device through processes typical of polymer melts, solutions, and dispersions and then crossed linked to a shape memory thermoset polymer retaining the processed shape.

  19. Post polymerization cure shape memory polymers

    Science.gov (United States)

    Wilson, Thomas S.; Hearon, II, Michael Keith; Bearinger, Jane P.

    2017-01-10

    This invention relates to chemical polymer compositions, methods of synthesis, and fabrication methods for devices regarding polymers capable of displaying shape memory behavior (SMPs) and which can first be polymerized to a linear or branched polymeric structure, having thermoplastic properties, subsequently processed into a device through processes typical of polymer melts, solutions, and dispersions and then crossed linked to a shape memory thermoset polymer retaining the processed shape.

  20. Optical Nonlinear Properties of Gold Nanoparticles Synthesized by Laser Ablation in Polymer Solution

    Directory of Open Access Journals (Sweden)

    M. Tajdidzadeh

    2017-01-01

    Full Text Available In the present study, gold nanoparticles were synthesized in various polymer solutions by means of employing laser ablation technique at the same ablation time. Specifically, gold nanoparticles were synthesized in polyethylene glycol and chitosan solutions, in order to compare the effects of the liquid media which served as stabilizers for particle size and volume fraction of nanoparticles. In addition, this experiment was repeated in distilled water for reference purposes. As the findings indicated, the particle size which was obtained in polyethylene glycol was about 7.49 nm, that is, smaller than those of chitosan solution and distilled water, respectively. In contrast, it was observed that the volume fraction of gold nanoparticles increased in polyethylene glycol in comparison with the other media which indicated an effect on the formation of NPs. On the other hand, Z-scan technique was employed to measure the nonlinear refractive index and nonlinear absorption coefficient of nanofluids containing gold nanoparticles. Consequently, the nonlinear properties of nanofluids pointed to a significant contribution with the number of nanoparticles observed in fluids and both optical nonlinear parameters were observed to increase by means of a prior increase in the volume fraction of Au-NPs in polyethylene glycol solution.

  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. Inclusion of mPRISM potential for polymer-induced protein interactions enables modeling of second osmotic virial coefficients in aqueous polymer-salt solutions.

    Science.gov (United States)

    Herhut, Marcel; Brandenbusch, Christoph; Sadowski, Gabriele

    2016-01-01

    The downstream processing of therapeutic proteins is a challenging task. Key information needed to estimate applicable workup strategies (e.g. crystallization) are the interactions of the proteins with other components in solution. This information can be deduced from the second osmotic virial coefficient B22 , measurable by static light scattering. Thermodynamic models are very valuable for predicting B22 data for different process conditions and thus decrease the experimental effort. Available B22 models consider aqueous salt solutions but fail for the prediction of B22 if an additional polymer is present in solution. This is due to the fact that depending on the polymer concentration protein-protein interactions are not rectified as assumed within these models. In this work, we developed an extension of the xDLVO model to predict B22 data of proteins in aqueous polymer-salt solutions. To show the broad applicability of the model, lysozyme, γ-globulin and D-xylose ketol isomerase in aqueous salt solution containing polyethylene glycol were considered. For all proteins considered, the modified xDLVO model was able to predict the experimentally observed non-monotonical course in B22 data with high accuracy. When used in an early stage in process development, the model will contribute to an efficient and cost effective downstream processing development.

  4. Remarkable swelling capability of amino acid based cross-linked polymer networks in organic and aqueous medium.

    Science.gov (United States)

    Roy, Saswati Ghosh; Haldar, Ujjal; De, Priyadarsi

    2014-03-26

    This work reports design and synthesis of side chain amino acid based cross-linked polymeric gels, able to switch over from organogel to hydrogel by a simple deprotection reaction and showing superabsorbancy in water. Amino acid based methacrylate monomers, tert-butoxycarbonyl (Boc)-l/d-alanine methacryloyloxyethyl ester (Boc-l/d-Ala-HEMA), have been polymerized in the presence of a cross-linker via conventional free radical polymerization (FRP) and the reversible addition-fragmentation chain transfer (RAFT) technique for the synthesis of cross-linked polymer gels. The swelling behaviors of these organogels are investigated in organic solvents, and they behave as superabsorbent materials for organic solvents such as dichloromethane, acetone, tetrahydrofuran, etc. Swollen cross-linked polymer gels release the absorbed organic solvent rapidly. After Boc group deprotection from the pendant alanine moiety, the organogels transform to the hydrogels due to the formation of side chain ammonium (-NH3(+)) groups, and these hydrogels showed a significantly high swelling ratio (∼560 times than their dry volumes) in water. The morphology of organogels and hydrogels is studied by field emission scanning electron microscopy (FE-SEM). Amino acid based cross-linked gels could find applications as absorbents for oil spilled on water as well as superabsorbent hydrogels.

  5. Power-Aware Routing and Network Design with Bundled Links: Solutions and Analysis

    Directory of Open Access Journals (Sweden)

    Rosario G. Garroppo

    2013-01-01

    Full Text Available The paper deeply analyzes a novel network-wide power management problem, called Power-Aware Routing and Network Design with Bundled Links (PARND-BL, which is able to take into account both the relationship between the power consumption and the traffic throughput of the nodes and to power off both the chassis and even the single Physical Interface Card (PIC composing each link. The solutions of the PARND-BL model have been analyzed by taking into account different aspects associated with the actual applicability in real network scenarios: (i the time for obtaining the solution, (ii the deployed network topology and the resulting topology provided by the solution, (iii the power behavior of the network elements, (iv the traffic load, (v the QoS requirement, and (vi the number of paths to route each traffic demand. Among the most interesting and novel results, our analysis shows that the strategy of minimizing the number of powered-on network elements through the traffic consolidation does not always produce power savings, and the solution of this kind of problems, in some cases, can lead to spliting a single traffic demand into a high number of paths.

  6. 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.

  7. PEG encapsulated by porous triamide-linked polymers as support for solid-liquid phase change materials for energy storage

    Science.gov (United States)

    Andriamitantsoa, Radoelizo S.; Dong, Wenjun; Gao, Hongyi; Wang, Ge

    2017-03-01

    A series of porous triamide-linked polymers labeled as PTP were prepared by condensation of 1,3,5-benzenetricarbonyl trichloride with benzene-1,4-diamine (A), 4,4‧-methylenediamine (B) and 1,3,5-triazine-2,4,6-triamine (C) respectively. The as-synthesized polymers exhibit permanent porosity and high surface areas which guarantee to hold polyethylene glycol (PEG) molecules in their network for shape-stabilized phase change materials. They possess different effects on the phase change properties of the composite due to their different porosities. PTP-A have intrinsic well-ordered morphology, microstructure and good enough pores to keep the PCMs compared to PTP-B and PTP-C. PEG 2000 used as PCMs could be retained up to 85 wt% in PTP-A polymer materials and these composites were defined as form-stable composite PCMs without the leakage of melted PCM. The thermal study revealed a good storage effect of encapsulated polymer and the enthalpy of melting increases in the order PTP-C storage capacity. The latent heats for melting and freezing was found to be 155 and 141.7 kJ/kg with a peak appearing at around 53.13 and 29.67 °C respectively. The study suggests that pore size is important for the preparation of shape-stabilized PCMs.

  8. In Vitro and in Vivo Evaluation of Novel Cross-Linked Saccharide Based Polymers as Bile Acid Sequestrants

    Directory of Open Access Journals (Sweden)

    Francisco Javier Lopez-Jaramillo

    2015-02-01

    Full Text Available Bile acid sequestrants (BAS represent a therapeutic approach for the management of hypercholesterolemia that relies on the cationic polymeric nature of BAS to selectively bind negatively charged bile acids. We hypothesized that the cross-linking of β-cyclodextrin (β-CD and saccharides such as starch or dextrin with divinyl sulfone (DVS yields homo- and hetero-polymeric materials with the ability to trap sterols. Our hypothesis was put to test by synthesizing a library of 22 polymers that were screened to evaluate their capability to sequester both cholesterol (CHOL and cholic and deoxycholic acids (CA and DCA. Three polymers synthesized in high yield were identified as promising. Two were neutral hetero-polymers of β-CD and starch or dextrin and the third was a weakly cationic homo-polymer of starch, highlighting the importance of the cavity effect. They were tested in hypercholesterolemic male Wistar rats and their ability to regulate hypercholesterolemia was similar to that for the reference BAS cholestyramine, but with two additional advantages: (i they normalized the TG level and (ii they did not increase the creatinine level. Neither hepatotoxicity nor kidney injury was detected, further supporting them as therapeutical candidates to manage hypercholesterolemia.

  9. Linking homogeneous and heterogeneous enantioselective catalysis through a self-assembled coordination polymer.

    Science.gov (United States)

    García, José I; López-Sánchez, Beatriz; Mayoral, José A

    2008-11-01

    Combining the advantages of homogeneous and heterogeneous enantioselective catalysis is possible through self-supported copper coordination polymers, based on a new kind of ditopic chiral ligand bearing two azabis(oxazoline) moieties. When the coordination polymer is used to catalyze a cyclopropanation reaction, it becomes soluble in reaction conditions but precipitates after reaction completion, allowing easy recovery and efficient reuse in the same reaction up to 14 times.

  10. Effect of Cross-Linking on the Structure and Growth of Polymer Films Prepared by Interfacial Polymerization.

    Science.gov (United States)

    Berezkin, Anatoly V; Kudryavtsev, Yaroslav V

    2015-11-10

    Interfacial polymerization of tri- and bifunctional monomers (A3B2 polymerization) is investigated by dissipative particle dynamics to reveal an effect of cross-linking on the reaction kinetics and structure of the growing polymer film. Regardless of the comonomer reactivity and miscibility, the kinetics in an initially bilayer melt passes from the reaction to diffusion control. Within the crossover period, branched macromolecules undergo gelation, which drastically changes the scenario of the polymerization process. Comparison with the previously studied linear interfacial polymerization (Berezkin, A. V.; Kudryavtsev, Y. V. Linear Interfacial Polymerization: Theory and Simulations with Dissipative Particle Dynamics J. Chem. Phys. 2014, 141, 194906) shows similar conversion rates but very different product characteristics. Cross-linked polymer films are markedly heterogeneous in density, their average polymerization degree grows with the comonomer miscibility, and end groups are mostly trapped deeply in the film core. Products of linear interfacial polymerization demonstrate opposite trends as they are spontaneously homogenized by a convective flow of macromolecules expelled from the reactive zone to the film periphery, which we call the reactive extrusion effect and which is hampered in branched polymerization. Influence of the comonomer architecture on the polymer film characteristics could be used in various practical applications of interfacial polymerization, such as fabrication of membranes, micro- and nanocapsules and 3D printing.

  11. [Synthesis and structure of silver(I) coordination polymers with bis(pyridyl) ligands linked by an aromatic sulfonamide].

    Science.gov (United States)

    Katagiri, Kosuke

    2014-01-01

    Aromatic sulfonamides exist in a synclinal conformation with the twisted structure arising from rotation around the S-N bond in both the solid state and in solution. Simple bidentate ligands containing the sulfonamide moiety can be extended to form elongated ligands, and optically active components can be added to form a versatile building block for the construction of coordination polymers with many structures. Mixing the simple ligands 1 and 2 and the elongated ligands 3 and 4 with different Ag(I) salts yielded the corresponding complexes [Ag(1)OTf]n (1a), [Ag(2)]n•nOTf(2a), [Ag(3)OTf]n (3a), [Ag(3)]n•nBF₄ (3b), [Ag(4)CH₃CN]n•nBF₄•nCHCl₃ (4b), and [Ag(4)]n•nSbF₆•nCH₄O (4c). Straight chains and racemic helical polymers were observed in the crystal structure of complexes 1a and 2a, respectively. In the crystal structures of complexes 3a and 4b, infinite 1D straight chains containing a T-shaped coordination geometry about the Ag(I) centers were formed by the reaction of ligands 3 or 4 with Ag(I) salts in CH₃CN/CHCl₃. A continuous 1D coordination polymer containing a racemic mixture of left- and right-handed helices formed in the crystal structure of complex 3b. Furthermore, a layered coordination polymer consisting of a racemic mixture of left- and right-handed polymers was observed from the crystal structure of complex 4c. The construction of optically pure left- or right-handed 1D helical polymers via the introduction of chiral functional groups on the nitrogen atom of the sulfonamide ligand is currently under investigation in our laboratory.

  12. Mimicking conjugated polymer thin-film photophysics with a well-defined triblock copolymer in solution.

    Science.gov (United States)

    Brazard, Johanna; Ono, Robert J; Bielawski, Christopher W; Barbara, Paul F; Vanden Bout, David A

    2013-04-25

    Conjugated polymers (CPs) are promising materials for use in electronic applications, such as low-cost, easily processed organic photovoltaic (OPV) devices. Improving OPV efficiencies is hindered by a lack of a fundamental understanding of the photophysics in CP-based thin films that is complicated by their heterogeneous nanoscale morphologies. Here, we report on a poly(3-hexylthiophene)-block-poly(tert-butyl acrylate)-block-poly(3-hexylthiophene) rod-coil-rod triblock copolymer. In good solvents, this polymer resembles solutions of P3HT; however, upon the addition of a poor solvent, the two P3HT chains within the triblock copolymer collapse, affording a material with electronic spectra identical to those of a thin film of P3HT. Using this new system as a model for thin films of P3HT, we can attribute the low fluorescence quantum yield of films to the presence of a charge-transfer state, providing fundamental insights into the condensed phase photophysics that will help to guide the development of the next generation of materials for OPVs.

  13. A novel polymer inclusion membrane applied in chromium (VI) separation from aqueous solutions.

    Science.gov (United States)

    Gherasim, Cristina-Veronica; Bourceanu, Gelu; Olariu, Romeo-Iulian; Arsene, Cecilia

    2011-12-15

    In the present work, we analyze the transport properties of a novel polymer inclusion membrane (PIM) containing a poly-vinyl chloride (PVC) polymer matrix and the organic anion exchanger Aliquat 336 as a specific carrier, without addition of plasticizers. The study was specifically focused on the transport properties of Cr(VI) in conditions simulating industrial wastewaters. We analyzed the impact of several parameters on the Cr(VI) transport process such as: the carrier content of the PIM, the pH, and the phases' composition. We concluded that efficient transport processes occur through a PIM containing 40% Aliquat 336/60% PVC (w/w). The process is very fast and efficient for solutions of initial Cr(VI) concentration smaller than 10(-3)mol/L, in which nearly all of Cr(VI) is removed within 3h. The performed experiments prove that Cr(VI) transport through the membrane is a facilitated counter-transport process. The obtained results sustain that this novel non-plasticized membrane possesses enhanced transport properties towards other liquid membranes and plasticized PIMs previously reported as used for Cr(VI) transport. Additionally, it possesses an excellent reliability and a high selectivity for Cr(VI) from mixtures with other metal ions and anions existing in the real industrial effluents. The PIM characterization highlights the plasticizing role of the carrier Aliquat 336.

  14. 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.

  15. 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......-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...... indicates the aggregates fonmed due to hydrophobic association. Upon heating the intensity of the scattering correlation peaks was found to decrease indicating the loss of the network structure due to thermal motion....

  16. Tuning the Microcavity of Organic Light Emitting Diodes by Solution Processable Polymer-Nanoparticle Composite Layers.

    Science.gov (United States)

    Preinfalk, Jan B; Schackmar, Fabian R; Lampe, Thomas; Egel, Amos; Schmidt, Tobias D; Brütting, Wolfgang; Gomard, Guillaume; Lemmer, Uli

    2016-02-01

    In this study, we present a simple method to tune and take advantage of microcavity effects for an increased fraction of outcoupled light in solution-processed organic light emitting diodes. This is achieved by incorporating nonscattering polymer-nanoparticle composite layers. These tunable layers allow the optimization of the device architecture even for high film thicknesses on a single substrate by gradually altering the film thickness using a horizontal dipping technique. Moreover, it is shown that the optoelectronic device parameters are in good agreement with transfer matrix simulations of the corresponding layer stack, which offers the possibility to numerically design devices based on such composite layers. Lastly, it could be shown that the introduction of nanoparticles leads to an improved charge injection, which combined with an optimized microcavity resulted in a maximum luminous efficacy increase of 85% compared to a nanoparticle-free reference device.

  17. A simple derivation of the critical condition for the ultrasonic atomization of polymer solutions.

    Science.gov (United States)

    Kim, Hyungsu; Lee, Jaegeun; Won, You-Yeon

    2015-08-01

    A simple model is proposed for the ultrasonic atomization of polymer solutions. In this model, the atomization process is approximated as an equilibrium process. It is shown that the minimum attainable droplet size is determined by two parameters, the (Rayleigh) acoustic pressure acting on the surface of the liquid, and the surface tension of the liquid. Increasing the viscosity of the liquid suppresses the formation of small-sized droplets because of increased attenuation of the sound wave and thus decreased acoustic pressure. Lowering the surface tension of the liquid (e.g., by spreading a surfactant film on the liquid surface) has the opposite effect of enhancing the formation of smaller droplets. Also, there exists a maximum limit for the droplet size, because when the produced droplet is too large, the aspiration flow is unable to carry the droplet against sedimentation. These predictions are supported by experimental observations.

  18. Modelling of solid polymer and direct methanol fuel cells: Phenomenological equations and analytical solutions

    Science.gov (United States)

    Kauranen, P. S.

    1993-04-01

    In the solid state concept of a direct methanol fuel cell (DMFC), methanol is directly oxidized at the anode of a solid polymer electrolyte fuel cell (SPEFC). Mathematical modelling of the transport and reaction phenomena within the electrodes and the electrolyte membrane is needed in order to get a closer insight into the operation of the fuel cell. In the work, macro-homogenous porous electrode and dilute solution theories are used to derive the phenomenological equations describing the transport and reaction mechanisms in a SPEFC single cell. The equations are first derived for a conventional H2/air SPEFC, and then extended for a DMFC. The basic model is derived in a one dimensional form in which it is assumed that species transport take place only in the direction crossing the cell sandwich. In addition, two dimensional descriptions of the catalyst layer are reviewed.

  19. 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.

  20. Investigation of Cross-Linked and Additive Containing Polymer Materials for Membranes with Improved Performance in Pervaporation and Gas Separation

    Directory of Open Access Journals (Sweden)

    Karl Kleinermanns

    2012-10-01

    Full Text Available Pervaporation and gas separation performances of polymer membranes can be improved by crosslinking or addition of metal-organic frameworks (MOFs. Crosslinked copolyimide membranes show higher plasticization resistance and no significant loss in selectivity compared to non-crosslinked membranes when exposed to mixtures of CO2/CH4 or toluene/cyclohexane. Covalently crosslinked membranes reveal better separation performances than ionically crosslinked systems. Covalent interlacing with 3-hydroxypropyldimethylmaleimide as photocrosslinker can be investigated in situ in solution as well as in films, using transient UV/Vis and FTIR spectroscopy. The photocrosslinking yield can be determined from the FTIR-spectra. It is restricted by the stiffness of the copolyimide backbone, which inhibits the photoreaction due to spatial separation of the crosslinker side chains. Mixed-matrix membranes (MMMs with MOFs as additives (fillers have increased permeabilities and often also selectivities compared to the pure polymer. Incorporation of MOFs into polysulfone and Matrimid® polymers for MMMs gives defect-free membranes with performances similar to the best polymer membranes for gas mixtures, such as O2/N2 H2/CH4, CO2/CH4, H2/CO2, CH4/N2 and CO2/N2 (preferentially permeating gas is named first. The MOF porosity, its particle size and content in the MMM are factors to influence the permeability and the separation performance of the membranes.

  1. Correlation between wetting, adhesion and adsorption in the polymer-aqueous solutions of ternary surfactant mixtures-air systems

    Science.gov (United States)

    Szymczyk, Katarzyna; Zdziennicka, Anna; Krawczyk, Joanna; Jańczuk, Bronisław

    2014-01-01

    The correlation between the wettability of polymers and adsorption of ternary mixtures including CTAB, TX-100 and TX-114 at the polymer-aqueous solution interface as well as the adhesion of aqueous solution of these mixtures to apolar polytetrafluoroethylene (PTFE), monopolar polymethyl methacrylate (PMMA) and nylon 6 was considered on the basis of the contact angle measurements and the literature data of the solutions surface tension. From these considerations it appeared that the efficiency and effectiveness of the adsorption at the PTFE-water interface are comparable to those at the water-air one, but for the PMMA-water and nylon 6-water interfaces they are lower than those for the water-air one for a given series of solutions. The efficiency and effectiveness are reflected in the composition of the mixed monolayer at the polymer-solution interface which even for the PTFE-solution interface is somewhat different from the water-air interface. The properties of the mixed monolayer at these interfaces influence the critical surface tension of polymer wetting which for PTFE is somewhat higher but for PMMA and nylon 6 considerably lower than their surface tension. From these considerations it also appeared that the work of adhesion of aqueous solutions of ternary mixtures of surfactants to the PTFE surface does not depend on the composition and concentration of solution contrary to PMMA and nylon 6. The adhesion work of these solutions to the PMMA and nylon 6 surface can be determined on the basis of van Oss et al. and Neumann et al. equations.

  2. Threshold-like complexation of conjugated polymers with small molecule acceptors in solution within the neighbor-effect model.

    Science.gov (United States)

    Sosorev, Andrey Yu; Parashchuk, Olga D; Zapunidi, Sergey A; Kashtanov, Grigoriy S; Golovnin, Ilya V; Kommanaboyina, Srikanth; Perepichka, Igor F; Paraschuk, Dmitry Yu

    2016-02-14

    In some donor-acceptor blends based on conjugated polymers, a pronounced charge-transfer complex (CTC) forms in the electronic ground state. In contrast to small-molecule donor-acceptor blends, the CTC concentration in polymer:acceptor solution can increase with the acceptor content in a threshold-like way. This threshold-like behavior was earlier attributed to the neighbor effect (NE) in the polymer complexation, i.e., next CTCs are preferentially formed near the existing ones; however, the NE origin is unknown. To address the factors affecting the NE, we record the optical absorption data for blends of the most studied conjugated polymers, poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV) and poly(3-hexylthiophene) (P3HT), with electron acceptors of fluorene series, 1,8-dinitro-9,10-antraquinone (), and 7,7,8,8-tetracyanoquinodimethane () in different solvents, and then analyze the data within the NE model. We have found that the NE depends on the polymer and acceptor molecular skeletons and solvent, while it does not depend on the acceptor electron affinity and polymer concentration. We conclude that the NE operates within a single macromolecule and stems from planarization of the polymer chain involved in the CTC with an acceptor molecule; as a result, the probability of further complexation with the next acceptor molecules at the adjacent repeat units increases. The steric and electronic microscopic mechanisms of NE are discussed.

  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. Precise Synthesis of Block Polymers Composed of Three or More Blocks by Specially Designed Linking Methodologies in Conjunction with Living Anionic Polymerization System

    Directory of Open Access Journals (Sweden)

    Akira Hirao

    2013-07-01

    Full Text Available This article reviews the successful development of two specially designed linking methodologies in conjunction with a living anionic polymerization system for the synthesis of novel multiblock polymers, composed of three or more blocks, difficult to be synthesized by sequential polymerization. The first methodology with the use of a new heterofunctional linking agent, 2-(4-chloromethylphenylethyldimethylchlorosilane (1, was developed for the synthesis of multiblock polymers containing poly(dimethylsiloxane (PDMS blocks. This methodology is based on the selective reaction of the chain-end silanolate anion of living PDMS, with the silyl chloride function of 1, and subsequent linking reaction of the resulting ω-chain-end-benzyl chloride-functionalized polymer with either a living anionic polymer or living anionic block copolymer. With this methodology, various multiblock polymers containing PDMS blocks, up to the pentablock quintopolymer, were successfully synthesized. The second methodology using an α-phenylacrylate (PA reaction site was developed for the synthesis of multiblock polymers composed of all-vinyl polymer blocks. In this methodology, an α-chain-end-PA-functionalized polymer or block copolymer, via the living anionic polymerization, was first prepared and, then, reacted with appropriate living anionic polymer or block copolymer to link the two polymer chains. As a result, ACB (BCA, BAC (CAB, (ABn, (ACn, ABA, ACA, BCB, and ABCA multiblock polymers, where A, B, and C were polystyrene, poly(2-vinylpyridine, and poly(methyl methacrylate segments, could be successfully synthesized. The synthesis of triblock copolymers, BAB, CAC, and CBC, having molecular asymmetry in both side blocks, was also achieved. Furthermore, the use of living anionic polymers, derived from many other monomers, categorized as either of styrene, 2-vinylpyridine, or methyl methacrylate in monomer reactivity, in the linking methodology enabled the number of

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

    Directory of Open Access Journals (Sweden)

    O. Arjmand

    2012-08-01

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

  6. Polymer assisted solution processing of Ti-doped indium oxide transparent conducting thin films for organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Vishwanath, Sujaya Kumar [Division of Advanced Materials Engineering, Kongju National University, Cheonan, Chungchungnam-do 331-717 (Korea, Republic of); Jin, Won-Yong [The Graduate School of Flexible and Printable Electronics, Polymer BIN Fusion Research Center, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Kang, Jae-Wook, E-mail: jwkang@jbnu.ac.kr [The Graduate School of Flexible and Printable Electronics, Polymer BIN Fusion Research Center, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Kim, Jihoon, E-mail: jihoon.kim@kongju.ac.kr [Division of Advanced Materials Engineering, Kongju National University, Cheonan, Chungchungnam-do 331-717 (Korea, Republic of)

    2015-05-15

    Highlights: • Polymer assisted solution process. • Ti-doped indium oxide (TIO) transparent conducting films. • Replacement of sputtered ITO with polymer-assisted-solution-coated TIO films. • High mobility transparent conducting films. • Application of polymer-assisted-solution-coated TIO films to organic solar cells. - Abstract: We report the preparation and evaluation of Ti-doped indium oxide (TIO) transparent conducting films by a polymer-assisted solution (PAS) process, as well as the evaluation of this type of film as a transparent cathode in an inverted organic solar cell (IOCS). Both Ti- and In-PASs have been synthesized by coordinating Ti- and In-anionic complexes with polyethyleneimine. The final TIO–PAS was formed by mixing Ti-PAS into In-PAS with a Ti concentration between 1 at.% and 7 at.%. The TIO–PAS was spin-coated onto glass substrates to form uniform thin films of Ti-doped indium oxide, which were then annealed at high temperature. The optimum Ti concentration to achieve the best electrical and optical properties of PAS–TIO films was found to be 3 at.%. With the film thickness of 650 nm, PAS–TIO films had a sheet resistance of 65 Ω/sq and an optical transmittance greater than 85%. The feasibility of PAS-coated TIO thin film as a transparent electrode was evaluated by applying it to the fabrication of IOSCs, which showed the energy conversion efficiency of 4.60%.

  7. Investigation of optical spacer layers from solution based precursors for polymer solar cells using X-ray reflectometry

    DEFF Research Database (Denmark)

    Andersen, Philip Hvidthøft Delff; Skårhøj, Jakob; Andreasen, Jens Wenzel

    2009-01-01

    Optical spacer layers based on titaniumalkoxide precursor solutions were prepared by spin-coating on top of bulk heterojunction layers based on poly-3-hexylthiophene (P3HT) and phenyl-C61-butyric acid methylester (PCBM). Models and experiment have shown that the performance of polymer solar cells...

  8. Effect of acid-catalyzed formation rates of benzimidazole-linked polymers on porosity and selective CO2 capture from gas mixtures.

    Science.gov (United States)

    Altarawneh, Suha; İslamoğlu, Timur; Sekizkardes, Ali Kemal; El-Kaderi, Hani M

    2015-04-01

    Benzimidazole-linked polymers (BILPs) are emerging candidates for gas storage and separation applications; however, their current synthetic methods offer limited control over textural properties which are vital for their multifaceted use. In this study, we investigate the impact of acid-catalyzed formation rates of the imidazole units on the porosity levels of BILPs and subsequent effects on CO2 and CH4 binding affinities and selective uptake of CO2 over CH4 and N2. Treatment of 3,3'-Diaminobenzidine tetrahydrochloride hydrate with 1,2,4,5-tetrakis(4-formylphenyl)benzene and 1,3,5-(4-formylphenyl)-benzene in anhydrous DMF afforded porous BILP-15 (448 m(2) g(-1)) and BILP-16 (435 m(2) g(-1)), respectively. Alternatively, the same polymers were prepared from the neutral 3,3'-Diaminobenzidine and catalytic amounts of aqueous HCl. The resulting polymers denoted BILP-15(AC) and BILP-16(AC) exhibited optimal surface areas; 862 m(2) g(-1) and 643 m(2) g(-1), respectively, only when 2 equiv of HCl (0.22 M) was used. In contrast, the CO2 binding affinity (Qst) dropped from 33.0 to 28.9 kJ mol(-1) for BILP-15 and from 32.0 to 31.6 kJ mol(-1) for BILP-16. According to initial slope calculations at 273 K/298 K, a notable change in CO2/N2 selectivity was observed for BILP-15(AC) (61/50) compared to BILP-15 (83/63). Similarly, ideal adsorbed solution theory (IAST) calculations also show the higher specific surface area of BILP-15(AC) and BILP-16(AC) compromises their CO2/N2 selectivity.

  9. Removal of chromium(VI) from aqueous solutions by polymer inclusion membranes.

    Science.gov (United States)

    Kozlowski, Cezary A; Walkowiak, Wladyslaw

    2002-11-01

    The transport through polymer inclusion membranes (PIMs) was found as the effective and selective method of chromium(VI) anions removal from chloride acidic aqueous solutions. The optimal PIMs content was as follows: 41 wt% of cellulose triacetate as the support, 23 wt% of tri-n-octylamine as the ionic carrier, and 36 wt% of o-nitrophenyl pentyl ether as the plasticizer. The results obtained show a linear decrease of permeability coefficient and initial flux values with source phase pH increase. Also linear decrease of initial flux in log-log scale with chromium(VI) concentration increase was observed. Value of slope of this relationship was found to be 0.96 which indicates a first order of chromium(VI) reaction with tri-n-octylamine at membrane/aqueous source interface. Transport of chromium(VI) through PIMs reduces the concentration of chromium(VI) in source aqueous phase from 1.0 to 0.0028 ppm, which is below permissible limit in drinking water in Poland. Competitive transport of chromium(VI), cadmium(II), zinc(II), and iron(III) from acidic aqueous solution across PIMs was found to be efficient for chromium(VI) (99%), and cadmium(II) (99%).

  10. Polymer-based adsorbent for heavy metals removal from aqueous solution

    Science.gov (United States)

    Mahmud, H. N. M. E.; Huq, A. K. O.; Yahya, R.

    2017-06-01

    A novel conducting polymer-based adsorbent, polypyrrole (PPy) fine powder has successfully been prepared as a new adsorbent and utilized in the adsorption of heavy metal ions like arsenic, zinc and cadmium ions from aqueous solution. PPy was chemically synthesized by using FeCl3.6H2O as an oxidant. The prepared PPy adsorbent was characterized by Brunauer-Emmet-Teller (BET) surface analysis, field emission scanning electron microscopy (FESEM) and attenuated total reflectance fourier transform infrared ATR-(FTIR) spectroscopy. The adsorption was conducted by varying different parameters such as, contact time, pH and adsorbent dosage. The concentrations of metal ions were measured by inductively coupled plasma mass spectroscopy (ICP-MS). The results show that PPy acts as an effective sorbent for the removal of arsenic, zinc and cadmium ions from aqueous solution. The as-prepared PPy fine powder is easy to prepare and appeared as an effective adsorbent for heavy metal ions particularly arsenic in wastewater treatment.

  11. EXPERIMENTAL STUDY OF MICROSCALE FLOW FOR MICRO MOLECULE LIQUID AND POLYMER SOLUTION

    Institute of Scientific and Technical Information of China (English)

    LIU Zhong-chun; YUE Xiang-an; HOU Ji-rui; ZHANG Li-juan

    2005-01-01

    The flow performances of water, white oil and Hydrolyzing Polyacrylamide (HPAM) solution in fused quartz channels and the effect of wettability on the microscale flows have been studied respectively in this paper. The adaptability of classical fluid mechanics in channels with different sizes has been discussed. The results show that water flows in channels of 2μm diameter also have few size effects and white oil flow accord with classical fluid mechanics theory in channels of 25μm diameter too, but polymer solution appears an obvious size effect as diameters of channels decrease to 16μm. The wettability does not produce any influences on the water or white oil flows in channels of 25μm or 50μm diameter. The experimental technology of microscale flows has been first applied for studying the flow performances of pores in low permeability reservoir. This study found a base for deep investigating the percolation mechanism in low permeability reservoirs.

  12. 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.

  13. Solution-phase laser processing of π-conjugated polymers: Switching between different molecular states

    Science.gov (United States)

    Takada, K.; Tomioka, A.

    2012-04-01

    Liquid-phase laser processing, where the laser-irradiated target material is immersed in water for cooling, has been reported as a promising processing technique for thermally fragile organic materials. Although nanometer-sized particles have been reported to be obtained with the liquid-phase laser processing, the physical property did not change because quantum-mechanical size effect does not exhibit itself in the zero-radius Frenkel excitons. In the present study, we step further to use solution droplets as a target material, where organic molecules are molecularly dispersed in organic solvent and, therefore, expected to easily alter the conformation and the energy state upon laser irradiation. Small volume organic solvent is quickly evaporated upon laser irradiation, letting the bare organic molecule placed in water and rapidly cooled. To prevent the chemical decomposition of the target π-conjugated molecule, the specimen was resonantly irradiated by a ns-pulse green laser, not by a conventional UV laser. When the solid state spin-coat film made from MEH-PPV chloroform solution was used as a irradiation target immersed in water, resulting MEH-PPV particles showed similar photoluminescence (PL) like the PL of the spin-coat film and PL of the chloroform solution, including the 0→1, 0→2 vibrational transitions: this indicates that the energy levels were not modified from the spin-coat film. In comparison, when tiny droplets of MEH-PPV chloroform solution (orange color) were suspended in water, laser irradiation gave rise to yellow MEH-PPV particles which showed 550 nm and 530 nm PL (type B), blue-shifted from the spin-coat film PL 580 nm (type A), suggesting a successful phase transition of MEH-PPV polymer to type B. Further solution-phase laser processing left the type B state unchanged. The irreversible phase transition from type A to type B suggests that the type B ground state has lower energy than type A, which is consistent with the blue-shifted PL of

  14. Solution conformation of C-linked antifreeze glycoprotein analogues and modulation of ice recrystallization.

    Science.gov (United States)

    Tam, Roger Y; Rowley, Christopher N; Petrov, Ivan; Zhang, Tianyi; Afagh, Nicholas A; Woo, Tom K; Ben, Robert N

    2009-11-01

    Antifreeze glycoproteins (AFGPs) are a unique class of proteins that are found in many organisms inhabiting subzero environments and ensure their survival by preventing ice growth in vivo. During the last several years, our laboratory has synthesized functional C-linked AFGP analogues (3 and 5) that possess custom-tailored antifreeze activity suitable for medical, commercial, and industrial applications. These compounds are potent inhibitors of ice recrystallization and do not exhibit thermal hysteresis. The current study explores how changes in the length of the amide-containing side chain between the carbohydrate moiety and the polypeptide backbone in 5 influences ice recrystallization inhibition (IRI) activity. Analogue 5 (n = 3, where n is the number of carbons in the side chain) was a potent inhibitor of ice recrystallization, while 4, 6, and 7 (n = 4, 2, and 1, respectively) exhibited no IRI activity. The solution conformation of the polypeptide backbone in C-linked AFGP analogues 4-7 was examined using circular dichroism (CD) spectroscopy. The results suggested that all of the analogues exhibit a random coil conformation in solution and that the dramatic increase in IRI activity observed with 5 is not due to a change in long-range solution conformation. Variable-temperature (1)H NMR studies on truncated analogues 26-28 failed to elucidate the presence of persistent intramolecular bonds between the amide in the side chain and the peptide backbone. Molecular dynamics simulations performed on these analogues also failed to show persistent intramolecular hydrogen bonds. However, the simulations did indicate that the side chain of IRI-active analogue 26 (n = 3) adopts a unique short-range solution conformation in which it is folded back onto the peptide backbone, orienting the more hydrophilic face of the carbohydrate moiety away from the bulk solvent. In contrast, the solution conformation of IRI-inactive analogues 25, 27, and 28 had fully extended side chains

  15. Linking water age and solute dynamics in streamflow at the Hubbard Brook Experimental Forest, NH, USA

    Science.gov (United States)

    Benettin, Paolo; Bailey, Scott W.; Campbell, John L.; Green, Mark B.; Rinaldo, Andrea; Likens, Gene E.; McGuire, Kevin J.; Botter, Gianluca

    2015-11-01

    We combine experimental and modeling results from a headwater catchment at the Hubbard Brook Experimental Forest (HBEF), New Hampshire, USA, to explore the link between stream solute dynamics and water age. A theoretical framework based on water age dynamics, which represents a general basis for characterizing solute transport at the catchment scale, is here applied to conservative and weathering-derived solutes. Based on the available information about the hydrology of the site, an integrated transport model was developed and used to compute hydrochemical fluxes. The model was designed to reproduce the deuterium content of streamflow and allowed for the estimate of catchment water storage and dynamic travel time distributions (TTDs). The innovative contribution of this paper is the simulation of dissolved silicon and sodium concentration in streamflow, achieved by implementing first-order chemical kinetics based explicitly on dynamic TTD, thus upscaling local geochemical processes to catchment scale. Our results highlight the key role of water stored within the subsoil glacial material in both the short-term and long-term solute circulation. The travel time analysis provided an estimate of streamflow age distributions and their evolution in time related to catchment wetness conditions. The use of age information to reproduce a 14 year data set of silicon and sodium stream concentration shows that, at catchment scales, the dynamics of such geogenic solutes are mostly controlled by hydrologic drivers, which determine the contact times between the water and mineral interfaces. Justifications and limitations toward a general theory of reactive solute circulation at catchment scales are discussed.

  16. Separation and quantification of viral double-stranded RNA fragments by capillary electrophoresis in hydroxyethylcellulose polymer solutions.

    Science.gov (United States)

    Shambaugh, C L; Bodmer, J L; Hsu, D; Ranucci, C S

    2004-10-01

    Capillary electrophoresis (CE) is an analytical technique widely utilized to resolve complex mixtures of nucleic acids. CE uses a variety of polymers in solution that act as a molecular sieve to separate nucleic acid fragments according to size. It has been shown previously that purified dsDNA can be resolved efficiently by solutions of hydroxyethylcellulose (HEC) polymer, providing a rapid and high resolution method of separation. We have applied this separation technique to viral double-stranded (ds) RNA segments derived from rotavirus process samples. HEC polymers of various molecular masses and concentrations were identified and compared for their ability to separate dsRNA based on the extent of expected polymer network formation. The HEC polymer exhibiting the most desirable separation characteristics was then used for subsequent optimization of various method parameters, such as, injection time, electric field strength, dye concentration and capillary equilibration. The optimized method was then applied to the quantification of genome concentration based on a representative segment of the rotavirus genome. This study demonstrated that purified viral dsRNA material of known concentration could be used to generate an external standard curve relating concentration to peak area. This standard curve was used to determine the concentration of unknown samples by interpolation. This novel RNA quantification assay is likely to be applicable to other types of virus, including those containing dsDNA.

  17. Solution-processed low dimensional nanomaterials with self-assembled polymers for flexible photo-electronic devices (Presentation Recording)

    Science.gov (United States)

    Park, Cheolmin

    2015-09-01

    Self assembly driven by complicated but systematic hierarchical interactions offers a qualified alternative for fabricating functional micron or nanometer scale pattern structures that have been potentially useful for various organic and nanotechnological devices. Self assembled nanostructures generated from synthetic polymer systems such as controlled polymer blends, semi-crystalline polymers and block copolymers have gained a great attention not only because of the variety of nanostructures they can evolve but also because of the controllability of these structures by external stimuli. In this presentation, various novel photo-electronic materials and devices are introduced based on the solution-processed low dimensional nanomaterials such as networked carbon nanotubes (CNTs), reduced graphene oxides (rGOs) and 2 dimensional transition metal dichalcogenides (TMDs) with self assembled polymers including field effect transistor, electroluminescent device, non-volatile memory and photodetector. For instance, a nanocomposite of networked CNTs and a fluorescent polymer turned out an efficient field induced electroluminescent layer under alternating current (AC) as a potential candidate for next generation displays and lightings. Furthermore, scalable and simple strategies employed for fabricating rGO as well as TMD nanohybrid films allowed for high performance and mechanically flexible non-volatile resistive polymer memory devices and broad band photo-detectors, respectively.

  18. 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

  19. Polymer pendant ligand chemistry. 3. A biomimetic approach to selective metal ion removal and recovery from aqueous solution with polymer-supported sulfonated catechol and linear catechol amide ligands

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Song-Ping; Li, Wei; Franz, K.J.; Albright, R.L.; Fish, R.H. [Univ. of California, Berkeley, CA (United States)

    1995-05-24

    The design of organic ligands to selectively remove and recover metal ions from aqueous solution is a new and important area of environmental inorganic chemistry. One approach to designing organic ligands for these purposes is to use biological systems as examples for selective metal ion complexation. Thus, the authors report results on the synthesis of several biomimetically important polymer-supported, sulfonated catechol (PS-CATS), sulfonated bis(catechol) linear amide (PS-2-6-LICAMS), and sulfonated 3.3-linear tris(catechol) amide (PS-3,3-LICAMS) ligands that are chemically bonded to modified 6% cross-linked macroporous polystyrene-divinylbenzene beads (PS-DVB) for selective removal and recovery of environmentally and economically important metal ions from aqueous solution, as a function of pH. The Fe{sup 3+} ion selectivity was dramatically shown for PS-CATS, PS-2-6-LICAMS and PS-3,3-LICAMS polymer beads in competition with a similar concentration of Cu{sup 2+}, Zn{sup 2+}, Mn{sup 2+}, Ni{sup 2+}, Mg{sup 2+}, Al{sup 3+}, and Cr{sup 3+} ions at pH 1-3, while metal ion selectivity could be changed at higher pH values in the absence of Fe{sup 3+} (for example, Hg{sup 2+} at pH 3). Rates of removal and recovery of the Fe{sup 3+} ion with the PS-CATS, PS-2-6LICAMS and PS-3,3-LICAMS polymer beads were also studied as well as relative equilibrium selectivity coefficient (K{sub m}) values for all metal competition studies.

  20. A simple experiment to determine the activation energy of the viscous flow of polymer solutions using a glass capillary viscometer

    Science.gov (United States)

    Rohindra, D. R.; Lata, R. A.; Coll, R. K.

    2012-09-01

    A simple viscometry experiment undertaken by an undergraduate polymer class as a research project is described. Viscosity is a measure of a fluid's resistance to flow and is affected by several factors, such as concentration and temperature. In this experiment, the viscosities of polyvinylpyrrolidone solutions (a polymeric material) of different concentrations were prepared in water and measured at various temperatures. The solution viscosity was found to increase gradually with increasing concentration up to ∼5 mass%, with a dramatic increase after this. The calculated viscosity of water at different temperatures was comparable to reported values. The activation energy of viscous flow (Ea) of the different solutions was calculated and followed a similar trend as that for the viscosities of solutions of various concentrations. This experiment allowed students to better understand and explain the behaviour of macromolecules with respect to changing concentration and temperature. Furthermore, students correlated the viscosity and Ea results to understand how an increase in the concentration of a polymer solution resulted in increased entanglement of the polymer chains, consequently leading to an increase in viscosity and an increase in the activation energy of viscous flow. This experiment is safe, low cost, simple and requires only readily available apparatus.

  1. Orientation and Relaxation of Polymer-clay Solutions Studied by Rheology and Small-angle Neutron Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Malwitz, M. M. [Louisiana State University; Butler, Paul D [ORNL; Porcar, L. [National Institute of Standards and Technology (NIST); Angelette, D. P. [Louisiana State University; Schmidt, G. [National Institute of Standards and Technology (NIST)

    2004-01-01

    The influence of shear on viscoelastic solutions of poly(ethylene oxide) (PEO) and clay [montmorillonite, i.e., Cloisite NA+ (CNA)] was investigated with rheology and small-angle neutron scattering (SANS). The steady-state viscosity and SANS were used to measure the shear-induced orientation and relaxation of the polymer and clay platelets. Anisotropic scattering patterns developed at much lower shear rates than in pure clay solutions. The scattering anisotropy saturated at low shear rates, and the CNA clay platelets aligned with the flow, with the surface normal parallel to the gradient direction. The cessation of shear led to partial and slow randomization of the CNA platelets, whereas extremely fast relaxation was observed for laponite (LRD) platelets. These PEO-CNA networklike solutions were compared with previously reported PEO-LRD networks, and the differences and similarities, with respect to the shear orientation, relaxation, and polymer-clay interactions, were examined.

  2. Effect of plasticizer on surface of free films prepared from aqueous solutions of salts of cationic polymers with different plasticizers

    Science.gov (United States)

    Bajdik, János; Fehér, Máté; Pintye-Hódi, Klára

    2007-06-01

    Acquisition of a more detailed understanding of all technological processes is currently a relevant tendency in pharmaceutical technology and hence in industry. A knowledge of film formation from dispersion of polymers is very important during the coating of solid dosage forms. This process and the structure of the film can be influenced by different additives. In the present study, taste-masking films were prepared from aqueous citric acid solutions of a cationic polymer (Eudragit ® E PO) with various hydrophilic plasticizers (glycerol, propylene glycol and different poly(ethylene glycols)). The mechanical properties, film thickness, wetting properties and surface free energy of the free films were studied. The aim was to evaluate the properties of surface of free films to predict the arrangement of macromolecules in films formed from aqueous solutions of salts of cationic polymers. A high molecular weight of the plasticizer decreased the work of deformation. The surface free energy and the polarity were highest for the film without plasticizer; the hydrophilic additives decreased these parameters. The direction of the change in polarity (a hydrophilic component caused a decrease in the polarity) was unexpected. It can be explained by the change in orientation of the macromolecules, a hydrophobic surface being formed. Examination of the mechanical properties and film thickness can furnish additional results towards a knowledge of film formation by this not frequently applied type of polymer from aqueous solution.

  3. 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

  4. Redox-controlled upper critical solution temperature behaviour of a nitroxide containing polymer in alcohol-water mixtures

    OpenAIRE

    Bertrand, Olivier; Vlad, Alexandru; Hoogenboom, Richard; Gohy, Jean-François

    2016-01-01

    Research on stimuli responsive polymers builds momentum as nature-inspired applications using man-made materials are increasingly sought. Here, we show for the first time the thermo-responsive upper critical solution temperature (UCST) behaviour of a nitroxide containing polymer based on (2,6,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO). It is demonstrated that poly(TEMPO methacrylate) (PTMA) exhibits a UCST-type cloud point temperature in alcohol-water mixtures that can be tuned by an external...

  5. 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.

  6. Initiated Chemical Vapor Deposition (iCVD) of Highly Cross-Linked Polymer Films for Advanced Lithium-Ion Battery Separators.

    Science.gov (United States)

    Yoo, Youngmin; Kim, Byung Gon; Pak, Kwanyong; Han, Sung Jae; Song, Heon-Sik; Choi, Jang Wook; Im, Sung Gap

    2015-08-26

    We report an initiated chemical vapor deposition (iCVD) process to coat polyethylene (PE) separators in Li-ion batteries with a highly cross-linked, mechanically strong polymer, namely, polyhexavinyldisiloxane (pHVDS). The highly cross-linked but ultrathin pHVDS films can only be obtained by a vapor-phase process, because the pHVDS is insoluble in most solvents and thus infeasible with conventional solution-based methods. Moreover, even after the pHVDS coating, the initial porous structure of the separator is well preserved owing to the conformal vapor-phase deposition. The coating thickness is delicately controlled by deposition time to the level that the pore size decreases to below 7% compared to the original dimension. The pHVDS-coated PE shows substantially improved thermal stability and electrolyte wettability. After incubation at 140 °C for 30 min, the pHVDS-coated PE causes only a 12% areal shrinkage (versus 90% of the pristine separator). The superior wettability results in increased electrolyte uptake and ionic conductivity, leading to significantly improved rate performance. The current approach is applicable to a wide range of porous polymeric separators that suffer from thermal shrinkage and poor electrolyte wetting.

  7. Novel SERS materials for multiplex biomolecular detection via controlled nanoparticle linking and polymer encapsulation

    Energy Technology Data Exchange (ETDEWEB)

    Braun, G B; Lee, S J; Laurence, T; Fera, N; Fabris, L; Bazan, G C; Moskovits, M; Reich, N O

    2008-07-21

    Over the past decade the emphasis on single-molecule sensitivity of surface-enhanced Raman spectroscopy (SERS) has brought to prominence the special role played by so-called SERS 'hot spots', oftentimes nanometer-scale junctions between nanostructures. In this report, optimally SERS enhancing silver clusters were synthesized using bifunctional linkers and polymer and/or protein encapsulation. The synthesis, which results in stable clusters even when stored for months or dried and re-dissolved, is scalable to large quantities. Using a sacrificial linker approach we also employ a permeable polymer/protein shell for general small molecule sensing. Finally, we utilize these nanomaterials by tagging specific epitopes on cancer cells and show that SERS signals from single clusters can be measured routinely.

  8. Fabrication of Redox-Responsive Degradable Capsule Particles by a Shell-Selective Photoinduced Cross-Linking Approach from Spherical Polymer Particles.

    Science.gov (United States)

    Kitayama, Yukiya; Takeuchi, Toshifumi

    2017-09-18

    In this study, a fabrication route towards functional capsule particles was successfully developed by means of a self-templating shell-selective cross-linking strategy that enables us to prepare shell-cross-linked hollow polymer particles directly from homogeneous spherical polymer particles. To prepare redox-responsive degradable capsule particles, a newly designed monomer bearing a photoinduced post-cross-linking group (cinnamoyl group) and a redox-environment-responsive cleavable group (disulfide group), N-cinnamoyl-N'-methyacryloylcystamine (MCC), was synthesized. Redox-responsive degradable capsule particles were successfully prepared from homogeneous spherical poly(MCC)-based particles by a self-templating shell-selective photoinduced cross-linking approach. Moreover, the cargo loading capability of the shell-cross-linked hollow particles was confirmed through a solvent exchange procedure using dyes, polymer precursors and anticancer reagents. Furthermore, redox-responsive degradability of the capsule polymer particles was also confirmed by adding a reducing agent for cleavage of the disulfide linkage. We hope that the efficient fabrication route of functional capsule particles directly from spherical polymer particles opens efficient routes for the fabrication of a wide range of capsule particles; in particular, this technique is robust, productive, and facile because neither additional sacrificial template particles nor toxic solvents are required. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Ocean acidification: Linking science to management solutions using the Great Barrier Reef as a case study.

    Science.gov (United States)

    Albright, Rebecca; Anthony, Kenneth R N; Baird, Mark; Beeden, Roger; Byrne, Maria; Collier, Catherine; Dove, Sophie; Fabricius, Katharina; Hoegh-Guldberg, Ove; Kelly, Ryan P; Lough, Janice; Mongin, Mathieu; Munday, Philip L; Pears, Rachel J; Russell, Bayden D; Tilbrook, Bronte; Abal, Eva

    2016-11-01

    Coral reefs are one of the most vulnerable ecosystems to ocean acidification. While our understanding of the potential impacts of ocean acidification on coral reef ecosystems is growing, gaps remain that limit our ability to translate scientific knowledge into management action. To guide solution-based research, we review the current knowledge of ocean acidification impacts on coral reefs alongside management needs and priorities. We use the world's largest continuous reef system, Australia's Great Barrier Reef (GBR), as a case study. We integrate scientific knowledge gained from a variety of approaches (e.g., laboratory studies, field observations, and ecosystem modelling) and scales (e.g., cell, organism, ecosystem) that underpin a systems-level understanding of how ocean acidification is likely to impact the GBR and associated goods and services. We then discuss local and regional management options that may be effective to help mitigate the effects of ocean acidification on the GBR, with likely application to other coral reef systems. We develop a research framework for linking solution-based ocean acidification research to practical management options. The framework assists in identifying effective and cost-efficient options for supporting ecosystem resilience. The framework enables on-the-ground OA management to be the focus, while not losing sight of CO2 mitigation as the ultimate solution.

  10. Miscibility of poly(lactic acid) and poly(ethylene oxide) solvent polymer blends and nanofibers made by solution blow spinning

    Science.gov (United States)

    The miscibility of blends of poly(lactic acid) (PLA) and poly(ethylene oxide) (PEO) was studied in polymer solutions by dilute solution viscometry and in solution blow spun nanofibers by microscopy (SEM, TEM) and by thermal and spectral analysis. Three blends of PLA and PEO were solution blended in...

  11. Clinical safety and wear resistance of the phospholipid polymer-grafted highly cross-linked polyethylene liner.

    Science.gov (United States)

    Moro, Toru; Takatori, Yoshio; Tanaka, Sakae; Ishihara, Kazuhiko; Oda, Hiromi; Kim, Yoon Taek; Umeyama, Takashige; Fukatani, Eisei; Ito, Hideya; Kyomoto, Masayuki; Oshima, Hirofumi; Tanaka, Takeyuki; Kawaguchi, Hiroshi; Nakamura, Kozo

    2016-11-03

    To reduce the production of wear particles and subsequent aseptic loosening, we created a human articular cartilage-mimicked surface for a highly cross-linked polyethylene liner, whose surface grafted layer consisted of a biocompatible phospholipid polymer, poly(2-methacryloyloxyethyl phosphorylcholine). Although our previous in vitro findings showed that poly(2-methacryloyloxyethyl phosphorylcholine)-grafted particles were biologically inert and caused no subsequent bone resorptive responses, and poly(2-methacryloyloxyethyl phosphorylcholine) grafting markedly decreased wear in hip joint simulator tests, the clinical safety, and in vivo wear resistance of poly(2-methacryloyloxyethyl phosphorylcholine)-grafted highly cross-linked polyethylene liners remained open to question. Therefore, in the present study, we evaluated clinical and radiographic outcomes of poly(2-methacryloyloxyethyl phosphorylcholine)-grafted highly cross-linked polyethylene liners 5 years subsequent to total hip replacement in 68 consecutive patients. No reoperation was required for any reason, and no adverse events were associated with the implanted liners. The average Harris Hip Score increased from 38.6 preoperatively to 96.5 5 years postoperatively, and health-related quality of life, as indicated by the Short Form 36 Health Survey, improved. Radiographic analyses showed no periprosthetic osteolysis or implant migration. Between 1 and 5 years postoperatively, the mean steady-state wear rate was 0.002 mm/year, which represented a marked reduction relative to other highly cross-linked polyethylene liners, and appeared to be unaffected by patient-related or surgical factors. Although longer follow up is required, poly(2-methacryloyloxyethyl phosphorylcholine)-grafted highly cross-linked polyethylene liners improved mid-term clinical outcomes. The clinical safety and wear-resistance results are encouraging with respect to the improvement of long-term clinical outcomes with poly(2

  12. 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.

  13. Polymères hydrosolubles d'origine naturelle et synthétique Relation structure/propriétés en solution Water-Soluble Polymers of Natural and Synthetic Origin. Structure/Property Relations in Solution

    Directory of Open Access Journals (Sweden)

    Muller G.

    2006-11-01

    Full Text Available Les polymères hydrosolubles utilisés dans les opérations pétrolières (forage, cimentation, stimulation, récupération assistée peuvent être d'origine très variée (polymères naturels, de fermentation, semi-synthétiques et synthétiques. Leur utilisation et leur efficacité sont directement liées à la connaissance de la relation existant entre leur structure chimique (macrostructure et microstructure et leurs propriétés en solution. Ce rapport fait la synthèse des divers types de polymères hydrosolubles qui ont un intérêt pratique et définit les paramètres structuraux et fonctionnels gouvernant leur efficacité en fonction d'un certain nombre de paramètres extérieurs (pH, salinité, température. The capacity of water-soluble polymers to modify the rheology of aqueous solutions explains their importance for various oil-recovery operations. The choice of the most appropriate polymer depends on its molecular and macromolecular properties in solution, which are closely related to the nature of their primary, secondary and tertiary structures and of their microstructure. This article describes the different types of water-soluble polymers that are of practical interest, and it defines the structural and functional parameters that govern their efficacy as a function of external parameters (pH, salinity and temperature. There are four main types of polymers, depending on their origin. They are :(a Natural biopolymers (of vegetable origin and biotechnological biopolymers (produced by microorganisms, i. e. neutral and/or charged polysaccharides. (b Modified biopolymers having synthetic side chains. (c Polyvinylsaccharides (synthetic side chains. (d Synthetic polymers. For all of them, it is indispensable to know the relationship between structure, conformation and functional properties. The solubility in water and the properties in solution of polysaccharides depend on four main factors: (i the presence of branched chains, (ii the

  14. 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

  15. ``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

  16. Mechanism of dialkyl phthalates removal from aqueous solution using γ-cyclodextrin and starch based polyurethane polymer adsorbents.

    Science.gov (United States)

    Okoli, Chukwunonso Peter; Adewuyi, Gregory Olufemi; Zhang, Qian; Diagboya, Paul N; Guo, Qingjun

    2014-12-19

    Phthalate esters have been known as potent endocrine disruptors and carcinogens; and their removal from water have been of considerable concern recently. In the present study, γ-cyclodextrin polyurethane polymer (GPP), γ-cyclodextrin/starch polyurethane copolymer (GSP), and starch polyurethane polymer (SPP) have been synthesized and characterized. Their adsorption efficiencies for the removal of dimethyl phthalate (DMP) and diethyl phthalate (DEP) from aqueous solutions were investigated. The characterization results showed the success of the synthesis. The isotherms were L-type, and both the Langmuir and Freundlich adsorption isotherm gave good fittings to the adsorption data. Adsorption mechanisms suggested that these adsorbents spontaneously adsorb phthalate molecules driven mainly by enthalpy change, and the adsorption process was attributed to multiple adsorbent-adsorbate interactions such as hydrogen bonding, π-π stacking, and pore filling. The results showed that starch and γ-cyclodextrin polyurethane polymer adsorbents have excellent potential as adsorbent materials for the removal of phthalates from the contaminated water.

  17. Stabilized sulfonated aromatic polymers by in situ solvothermal cross-linking

    Directory of Open Access Journals (Sweden)

    Maria Luisa eDi Vona

    2014-10-01

    Full Text Available The cross-link reaction via sulfone bridges of sulfonated polyetheretherketone (SPEEK by thermal treatment at 180 °C in presence of dimethylsulfoxide (DMSO is discussed. The modifications of properties subsequent to the cross-linking are presented. The mechanical strength as well as the hydrolytic stability increased with the thermal treatment time, i.e., with the degree of cross-linking. The proton conductivity was determined as function of temperature, IEC, degree of cross-linking and hydration number. The memory effect, which is the membrane ability to remember the water uptake reached at high temperature also at lower temperature, is exploited in order to achieve high values of conductivity. Membranes swelled at 110 °C can reach a conductivity of 0.14 S/cm at 80°C with a hydration number ( of 73.

  18. Solution-processed ultrasensitive polymer photodetectors with high external quantum efficiency and detectivity.

    Science.gov (United States)

    Liu, Xilan; Wang, Hangxing; Yang, Tingbin; Zhang, Wei; Gong, Xiong

    2012-07-25

    Operating at room temperature, polymer photodetectors (PDs) with external quantum efficiency approximately 80%, detectivity over 10(13) Jones, linear dynamic range over 120 dB, and dark current a few decades of nA/cm(2) were demonstrated. All these performance parameters were achieved by combined treatment of active layer with solvent vapor annealing and of polymer PDs with postproduction thermal annealing. These high performance parameters demonstrated that polymer PDs is comparable to or better than inorganic counterparts.

  19. Cold-spotting: linking primary care and public health to create communities of solution.

    Science.gov (United States)

    Westfall, John M

    2013-01-01

    By providing enhanced primary care and social services to patients with high utilization of expensive emergency and hospital care, there is evidence that their health can improve and their costs can be lowered. This type of "hot-spotting" improves the care of individual patients. It may be that these patients live in communities with disintegrated social determinants of health, little community support, and poor access to primary care. These "cold spots" in the community may be amenable to interventions targeted at linking primary care and public health at broader community and population levels. Building local communities of solution that address the individual and population may help decrease these cold spots, thereby eliminating the hot spots as well.

  20. Analytic solutions for links and triangles distributions in finite Barabási-Albert networks

    Science.gov (United States)

    Ferreira, Ricardo M.; de Almeida, Rita M. C.; Brunnet, Leonardo G.

    2017-01-01

    Barabási-Albert model describes many different natural networks, often yielding sensible explanations to the subjacent dynamics. However, finite size effects may prevent from discerning among different underlying physical mechanisms and from determining whether a particular finite system is driven by Barabási-Albert dynamics. Here we propose master equations for the evolution of the degrees, links and triangles distributions, solve them both analytically and by numerical iteration, and compare with numerical simulations. The analytic solutions for all these distributions predict the network evolution for systems as small as 100 nodes. The analytic method we developed is applicable for other classes of networks, representing a powerful tool to investigate the evolution of natural networks.

  1. A colourimetric method for the determination of the degree of chemical cross-linking in aspartic acid-based polymer gels

    Directory of Open Access Journals (Sweden)

    B. Gyarmati

    2015-02-01

    Full Text Available A 2,4,6-trinitrobenzenesulphonic acid (TNBS-based assay is developed to determine the degree of chemical cross-linking in aspartic acid-based polymer gels. The conventional colourimetric method for the quantitative determination of amine groups is difficult to use in polymer networks; thus, an improved method is developed to analyse polymer gels swollen in dimethyl sulfoxide (DMSO. Reaction products of the derivatizing reaction are examined by NMR. The chemical stability of the reagent is increased in DMSO, and the method shows satisfactory linearity and accuracy. The degree of chemical cross-linking in the investigated gels is close to its theoretical maximum, but the conversion of the pendant amine groups to cross-linking points is strongly dependent on the feed composition of the gels.

  2. Activation energy for mobility of dyes and proteins in polymer solutions: from diffusion of single particles to macroscale flow.

    Science.gov (United States)

    Sozański, Krzysztof; Wiśniewska, Agnieszka; Kalwarczyk, Tomasz; Hołyst, Robert

    2013-11-27

    We measure the activation energy Ea for the diffusion of molecular probes (dyes and proteins of radii from 0.52 to 6.9 nm) and for macroscopic flow in a model complex liquid-aqueous solutions of polyethylene glycol. We cover a broad range of polymer molecular weights, concentrations, and temperatures. Fluorescence correlation spectroscopy and rheometry experiments reveal a relationship between the excess of the activation energy in polymer solutions over the one in pure solvent ΔEa and simple parameters describing the structure of the system: probe radius, polymer hydrodynamic radius, and correlation length. ΔEa varies by more than an order of magnitude in the investigated systems (in the range of ca. 1-15 kJ/mol) and for probes significantly larger than the polymer hydrodynamic radius approaches the value measured for macroscopic flow. We develop an explicit formula describing the smooth transition of ΔEa from the diffusion of molecular probes to macroscopic flow. This formula is a reference for the quantitative analysis of specific interactions of moving nano-objects with their environment as well as active transport. For instance, the power developed by a molecular motor moving at constant velocity u is proportional to u2exp(Ea/RT).

  3. A Modified Mixing Rule for PSRK Model and Application for the Prediction of Vapor-Liquid Equilibria of Polymer Solutions

    Institute of Scientific and Technical Information of China (English)

    李敏; 王利生; J.Gmehling

    2004-01-01

    To extend the PSRK (predictive Soave-Redlich-Kwong equation of state) model to vapor-liquid equilibria of polymer solutions, a new EOS-gE mixing rule is applied in which the term ∑xiln(b/bi) in the PSRK mixing rule for the parameter a, and the combinatorial part in the original universal functional activity coefficient (UNIFAC) model are cancelled. To take into account the free volume contribution to the excess Gibbs energy in polymer solution, a quadratic mixing rule for the cross co-volume bij with an exponent equals to 1/2 is applied [bij1/2=1/2(bi1/2+bj1/2)]. The literature reported Soave-Redlich-Kwong equation of state (SRK EOS) parameters of i3 - 2- pure polymer are employed. The PSRK model with the modified mixing rule is used to predict the vapor-liquid equilibrium (VLE) of 37 solvent-polymer systems over a large range of temperature and pressure with satisfactory results.

  4. Stable Lithium Deposition Generated from Ceramic-Cross-Linked Gel Polymer Electrolytes for Lithium Anode.

    Science.gov (United States)

    Tsao, Chih-Hao; Hsiao, Yang-Hung; Hsu, Chun-Han; Kuo, Ping-Lin

    2016-06-22

    In this work, a composite gel electrolyte comprising ceramic cross-linker and poly(ethylene oxide) (PEO) matrix is shown to have superior resistance to lithium dendrite growth and be applicable to gel polymer lithium batteries. In contrast to pristine gel electrolyte, these nanocomposite gel electrolytes show good compatibility with liquid electrolytes, wider electrochemical window, and a superior rate and cycling performance. These silica cross-linkers allow the PEO to form the lithium ion pathway and reduce anion mobility. Therefore, the gel not only features lower polarization and interfacial resistance, but also suppresses electrolyte decomposition and lithium corrosion. Further, these nanocomposite gel electrolytes increase the lithium transference number to 0.5, and exhibit superior electrochemical stability up to 5.0 V. Moreover, the lithium cells feature long-term stability and a Coulombic efficiency that can reach 97% after 100 cycles. The SEM image of the lithium metal surface after the cycling test shows that the composite gel electrolyte with 20% silica cross-linker forms a uniform passivation layer on the lithium surface. Accordingly, these features allow this gel polymer electrolyte with ceramic cross-linker to function as a high-performance lithium-ionic conductor and reliable separator for lithium metal batteries.

  5. 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.

  6. Promoting wired links in wireless mesh networks: an efficient engineering solution.

    Science.gov (United States)

    Barekatain, Behrang; Raahemifar, Kaamran; Ariza Quintana, Alfonso; Triviño Cabrera, Alicia

    2015-01-01

    Wireless Mesh Networks (WMNs) cannot completely guarantee good performance of traffic sources such as video streaming. To improve the network performance, this study proposes an efficient engineering solution named Wireless-to-Ethernet-Mesh-Portal-Passageway (WEMPP) that allows effective use of wired communication in WMNs. WEMPP permits transmitting data through wired and stable paths even when the destination is in the same network as the source (Intra-traffic). Tested with four popular routing protocols (Optimized Link State Routing or OLSR as a proactive protocol, Dynamic MANET On-demand or DYMO as a reactive protocol, DYMO with spanning tree ability and HWMP), WEMPP considerably decreases the end-to-end delay, jitter, contentions and interferences on nodes, even when the network size or density varies. WEMPP is also cost-effective and increases the network throughput. Moreover, in contrast to solutions proposed by previous studies, WEMPP is easily implemented by modifying the firmware of the actual Ethernet hardware without altering the routing protocols and/or the functionality of the IP/MAC/Upper layers. In fact, there is no need for modifying the functionalities of other mesh components in order to work with WEMPPs. The results of this study show that WEMPP significantly increases the performance of all routing protocols, thus leading to better video quality on nodes.

  7. Promoting wired links in wireless mesh networks: an efficient engineering solution.

    Directory of Open Access Journals (Sweden)

    Behrang Barekatain

    Full Text Available Wireless Mesh Networks (WMNs cannot completely guarantee good performance of traffic sources such as video streaming. To improve the network performance, this study proposes an efficient engineering solution named Wireless-to-Ethernet-Mesh-Portal-Passageway (WEMPP that allows effective use of wired communication in WMNs. WEMPP permits transmitting data through wired and stable paths even when the destination is in the same network as the source (Intra-traffic. Tested with four popular routing protocols (Optimized Link State Routing or OLSR as a proactive protocol, Dynamic MANET On-demand or DYMO as a reactive protocol, DYMO with spanning tree ability and HWMP, WEMPP considerably decreases the end-to-end delay, jitter, contentions and interferences on nodes, even when the network size or density varies. WEMPP is also cost-effective and increases the network throughput. Moreover, in contrast to solutions proposed by previous studies, WEMPP is easily implemented by modifying the firmware of the actual Ethernet hardware without altering the routing protocols and/or the functionality of the IP/MAC/Upper layers. In fact, there is no need for modifying the functionalities of other mesh components in order to work with WEMPPs. The results of this study show that WEMPP significantly increases the performance of all routing protocols, thus leading to better video quality on nodes.

  8. Linking mineralisation process and sedimentary product in terrestrial carbonates using a solution thermodynamic approach

    Science.gov (United States)

    Rogerson, M.; Pedley, H. M.; Kelham, A.; Wadhawan, J. D.

    2014-04-01

    discontinuous (oncoidal) deposition. However, a strong microbiological division is demonstrated between these sites on the basis of suspended bacterial cell distribution, which reach a prominent maximum where tufa-like deposits are forming. We conclude that at high supersaturation, the thermodynamic properties of solutions provide a highly satisfactory means of linking process and product, raising the opportunity of identifying water characteristics from sedimentological/petrological characteristics of ancient deposits. At low supersaturation, we recommend that future research focuses on geomicrobiological processes rather than the more traditional, inorganic solution chemistry approach dominant in the past.

  9. Linking process and product in terrestrial carbonates using a solution thermodynamic approach

    Science.gov (United States)

    Rogerson, M.; Pedley, H. M.; Kelham, A.

    2013-09-01

    suspended bacterial cell distribution, which reach a prominent maximum where tufa-like deposits are forming. We conclude that at high supersaturation, the thermodynamic properties of solutions provide a highly satisfactory means of linking process and product, raising the opportunity of identifying water characteristics from sedimentological/petrological characteristics of ancient deposits. At low supersaturation, we recommend that future research focuses on geomicrobiological processes rather than the more traditional, inorganic solution chemistry approach dominant in the past.

  10. 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 previ...

  11. 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 previ...

  12. Polymers and surfactants in solution and at interfaces : a model study on detergency

    NARCIS (Netherlands)

    Torn, L.H.

    2000-01-01

    This thesis deals with detergency-related adsorption phenomena of (mixtures of) polymers and surfactants. Both types of molecules play an important role in the removal and subsequent stabilization of soil from a substrate. Starting with a model detergency system consisting of polymers, surfactants,

  13. WinLALS for a linked-atom least-square refinement program for helical polymers on WINDOWS PCs.

    Science.gov (United States)

    Okada, Kenji; Noguchi, Keiichi; Okuyama, Kenji; Arnott, Struther

    2003-07-01

    Fiber diffraction dada from polymers are sufficiently different in kind and quantity from single crystal data as to warrant analyses with a different emphasis: refinement of competing molecular models where torsion angles and bond angles are the explicit variables rather than atomic coordinates. The first linked-atom least-squares (LALS) refinement program had been devolved at Arnott's laboratories at King's College London [Arnott, S., Wonacott, A.J., 1966a. Polymer 7, 157] on mainframe and several revised versions were maintained at Purdue University [Smith, P.J.C., Arnott, S., 1978. Acta Crystallogr. Sect. A 34, 3; Chandrasekan, R. 2000. LALS Users Manual, Whistler Centre for Carbohydrate Researchm Purdue University, West Lafayette, IN] on workstation. Today the LALS users have to choose correctly any one program that they want to use, trigonometric or Bessel functions, from some versions. To develop a new WinLALS program based on the dimensioned version of the latest LALS2000 program [LALS Users Manual (2000)], we reviewed all the mathematical expressions and corrected the optimization of the non-bonded atomic contact terms. The WinLALS is coded with FORTRAN 90 and runs on MICROSOFT-WINDOWS PCs and the many amendments including changing input/output assignments, expanding array sizes, arranging that the update files have all output parameters of each cycle, and correcting several bugs are performed. This paper describes the mathematical expressions in detail employed in WinLALS and compares results of its applications obtained with those obtained earlier.

  14. Development of atom transfer radical polymer-modified gold nanoparticle-based enzyme-linked immunosorbent assay (ELISA).

    Science.gov (United States)

    Chen, Feng; Hou, Shike; Li, Qingsheng; Fan, Haojun; Fan, Rong; Xu, Zhongwei; Zhala, Gahu; Mai, Xia; Chen, Xiaoyi; Chen, Xuyi; Liu, Yingfu

    2014-10-21

    In this work, a novel enzyme-linked immunosorbent assay (ELISA) with a low limit of detection and high sensitivity was developed using atom transfer radical polymer (ATRP)-modified gold nanoparticles (AuNPs). Clear signal amplification was achieved by introducing an abundance of horseradish peroxidase (HRP) to the AuNPs, because of the ATRP modification. This result suggested that the new ELISA was able to detect antigens in complex mixtures, and the limit of detection (LOD) was lower than that of conventional ELISA by a factor of 81. The new ELISA strategy greatly decreased the LOD during analysis and exhibited excellent reproducibility, stability, and feasibility. Therefore, it is a promising technique with many potential applications in biochemistry and medical science research.

  15. 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.

  16. Rapid prototyping of all-solution-processed multi-lengthscale electrodes using polymer-induced thin film wrinkling

    Science.gov (United States)

    Gabardo, Christine M.; Adams-McGavin, Robert C.; Fung, Barnabas C.; Mahoney, Eric J.; Fang, Qiyin; Soleymani, Leyla

    2017-02-01

    Three-dimensional electrodes that are controllable over multiple lengthscales are very important for use in bioanalytical systems that integrate solid-phase devices with solution-phase samples. Here we present a fabrication method based on all-solution-processing and thin film wrinkling using smart polymers that is ideal for rapid prototyping of tunable three-dimensional electrodes and is extendable to large volume manufacturing. Although all-solution-processing is an attractive alternative to vapor-based techniques for low-cost manufacturing of electrodes, it often results in films suffering from low conductivity and poor substrate adhesion. These limitations are addressed here by using a smart polymer to create a conformal layer of overlapping wrinkles on the substrate to shorten the current path and embed the conductor onto the polymer layer. The structural evolution of these wrinkled electrodes, deposited by electroless deposition onto a nanoparticle seed layer, is studied at varying deposition times to understand its effects on structural parameters such as porosity, wrinkle wavelength and height. Furthermore, the effect of structural parameters on functional properties such as electro-active surface area and surface-enhanced Raman scattering is investigated. It is found that wrinkling of electroless-deposited thin films can be used to reduce sheet resistance, increase surface area, and enhance the surface-enhanced Raman scattering signal.

  17. A unifying model for elongational flow of polymer melts and solutions based on the interchain tube pressure concept

    Science.gov (United States)

    Wagner, Manfred Hermann; Rolón-Garrido, Víctor Hugo

    2015-04-01

    An extended interchain tube pressure model for polymer melts and concentrated solutions is presented, based on the idea that the pressures exerted by a polymer chain on the walls of an anisotropic confinement are anisotropic (M. Doi and S. F. Edwards, The Theory of Polymer Dynamics, Oxford University Press, New York, 1986). In a tube model with variable tube diameter, chain stretch and tube diameter reduction are related, and at deformation rates larger than the inverse Rouse time τR, the chain is stretched and its confining tube becomes increasingly anisotropic. Tube diameter reduction leads to an interchain pressure in the lateral direction of the tube, which is proportional to the 3rd power of stretch (G. Marrucci and G. Ianniruberto. Macromolecules 37, 3934-3942, 2004). In the extended interchain tube pressure (EIP) model, it is assumed that chain stretch is balanced by interchain tube pressure in the lateral direction, and by a spring force in the longitudinal direction of the tube, which is linear in stretch. The scaling relations established for the relaxation modulus of concentrated solutions of polystyrene in oligomeric styrene (M. H. Wagner, Rheol. Acta 53, 765-777, 2014, M. H. Wagner, J. Non-Newtonian Fluid Mech. http://dx.doi.org/10.1016/j.jnnfm.2014.09.017, 2014) are applied to the solutions of polystyrene (PS) in diethyl phthalate (DEP) investigated by Bhattacharjee et al. (P. K. Bhattacharjee et al., Macromolecules 35, 10131-10148, 2002) and Acharya et al. (M. V. Acharya et al. AIP Conference Proceedings 1027, 391-393, 2008). The scaling relies on the difference ΔTg between the glass-transition temperatures of the melt and the glass-transition temperatures of the solutions. ΔTg can be inferred from the reported zero-shear viscosities, and the BSW spectra of the solutions are obtained from the BSW spectrum of the reference melt with good accuracy. Predictions of the EIP model are compared to the steady-state elongational viscosity data of PS

  18. Polymer physics

    CERN Document Server

    Gedde, Ulf W

    1999-01-01

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

  19. The Performance of a Thermally Cross-Linked Polymer of Intrinsic Microporosity (PIM-1) for Gas Separation

    KAUST Repository

    Alghunaimi, Fahad I.

    2013-05-01

    Gas transport properties of PIM-1 (the first ladder polymer with intrinsic microporosity) and TC-PIM-1 (thermally cross-linked PIM-1) at 35°C and different pressures were thoroughly studied. The purpose of this study was to evaluate and compare the performance of the TC-PIM-1 membranes with PIM-1 for natural gas separation. The TC-PIM-1 polymer was prepared by post-modification of PIM-1 at 300°C for a period of two days. Sorption isotherms of seven gases, including N2, O2, CH4, CO2, C2H6, C3H8 and n-C4H10, were determined for PIM-1 and TC-PIM-1 using the dual-volume barometric sorption technique at 35°C at different pressures. The sorption isotherms followed the dual-mode sorption model, which is typical for glassy polymers. Moreover, permeability (P) of eight gases, including He, H2, N2, O2, CH4, CO2, C3H8 and n-C4H10, were determined for PIM-1 and TC-PIM-1 at 35°C and 2.0 atm. Furthermore, average diffusion coefficients (D ̅) were calculated from the permeability and solubility data for all tested gases for both polymers. The sorption (S), permeability (P) and average diffusion coefficients (D ̅) for the TC-PIM-1 membrane exhibited lower values than the PIM-1 membrane. However, the TC-PIM-1 membrane showed exceptional gas separation performance. The TC-PIM-1 membrane had a helium (He) permeability of 1218 barrer with He/CH4 and He/N2 ideal selectivities of 27.1 and 23.9 respectively, and carbon dioxide (CO2) permeability of 1088 barrer with CO2/CH4 and CO2/N2 ideal selectivities of 24.2 and 21.3 respectively. Additionally, the TC-PIM-1 membrane showed a hydrogen (H2) permeability of 2452 barrer with an ideal H2/CH4 selectivity of 54.5.

  20. 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.

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

    Science.gov (United States)

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

    2015-07-01

    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(d(f)=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. Surface segregation of fluorinated moieties on random copolymer films controlled by random-coil conformation of polymer chains in solution.

    Science.gov (United States)

    Xue, Dongwu; Wang, Xinping; Ni, Huagang; Zhang, Wei; Xue, Gi

    2009-02-17

    The relationship between solution properties, film-forming methods, and the solid surface structures of random copolymers composed of butyl methacrylate and dodecafluorheptyl methylacrylate (DFHMA) was investigated by contact angle measurements, X-ray photoelectron spectroscopy, sum frequency generation vibrational spectroscopy, and surface tension measurements. The results, based on thermodynamic considerations, demonstrated that the random copolymer chain conformation at the solution/air interface greatly affected the surface structure of the resulting film, thereby determining the surface segregation of fluorinated moieties on films obtained by various film-forming techniques. When the fluorinated monomer content of the copolymer solution was low, entropic forces dominated the interfacial structure, with the perfluoroalkyl groups unable to migrate to the solution/air interface and thus becoming buried in a random-coil chain conformation. When employing this copolymer solution for film preparation by spin-coating, the copolymer chains in solution were likely extended due to centrifugal forces, thereby weakening the entropy effect of the polymer chains. Consequently, this resulted in the segregation of the fluorinated moieties on the film surface. For the films prepared by casting, the perfluoroalkyl groups were, similar to those in solution, incapable of segregating at the film surface and were thus buried in the random-coil chains. When the copolymers contained a high content of DFHMA, the migration of perfluoroalkyl groups at the solution/air interface was controlled by enthalpic forces, and the perfluoroalkyl groups segregated at the surface of the film regardless of the film-forming technique. The aim of the present work was to obtain an enhanced understanding of the formation mechanism of the chemical structure on the surface of the polymer film, while demonstrating that film-forming methods may be used in practice to promote the segregation of fluorinated

  3. 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....

  4. Oxidation increases mucin polymer cross-links to stiffen airway mucus gels.

    Science.gov (United States)

    Yuan, Shaopeng; Hollinger, Martin; Lachowicz-Scroggins, Marrah E; Kerr, Sheena C; Dunican, Eleanor M; Daniel, Brian M; Ghosh, Sudakshina; Erzurum, Serpel C; Willard, Belinda; Hazen, Stanley L; Huang, Xiaozhu; Carrington, Stephen D; Oscarson, Stefan; Fahy, John V

    2015-02-25

    Airway mucus in cystic fibrosis (CF) is highly elastic, but the mechanism behind this pathology is unclear. We hypothesized that the biophysical properties of CF mucus are altered because of neutrophilic oxidative stress. Using confocal imaging, rheology, and biochemical measures of inflammation and oxidation, we found that CF airway mucus gels have a molecular architecture characterized by a core of mucin covered by a web of DNA and a rheological profile characterized by high elasticity that can be normalized by chemical reduction. We also found that high levels of reactive oxygen species in CF mucus correlated positively and significantly with high concentrations of the oxidized products of cysteine (disulfide cross-links). To directly determine whether oxidation can cross-link mucins to increase mucus elasticity, we exposed induced sputum from healthy subjects to oxidizing stimuli and found a marked and thiol-dependent increase in sputum elasticity. Targeting mucin disulfide cross-links using current thiol-amino structures such as N-acetylcysteine (NAC) requires high drug concentrations to have mucolytic effects. We therefore synthesized a thiol-carbohydrate structure (methyl 6-thio-6-deoxy-α-D-galactopyranoside) and found that it had stronger reducing activity than NAC and more potent and fast-acting mucolytic activity in CF sputum. Thus, oxidation arising from airway inflammation or environmental exposure contributes to pathologic mucus gel formation in the lung, which suggests that it can be targeted by thiol-modified carbohydrates.

  5. Nature Inspired Solutions for Polymers: Will Cutinase Enzymes Make Polyesters and Polyamides Greener?

    Directory of Open Access Journals (Sweden)

    Valerio Ferrario

    2016-12-01

    Full Text Available The polymer and plastic sectors are under the urge of mitigating their environmental impact. The need for novel and more benign catalysts for polyester synthesis or targeted functionalization led, in recent years, to an increasing interest towards cutinases due to their natural ability to hydrolyze ester bonds in cutin, a natural polymer. In this review, the most recent advances in the synthesis and hydrolysis of various classes of polyesters and polyamides are discussed with a critical focus on the actual perspectives of applying enzymatic technologies for practical industrial purposes. More specifically, cutinase enzymes are compared to lipases and, in particular, to lipase B from Candida antarctica, the biocatalyst most widely employed in polymer chemistry so far. Computational and bioinformatics studies suggest that the natural role of cutinases in attacking natural polymers confer some essential features for processing also synthetic polyesters and polyamides.

  6. 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.

  7. A Study of The Elongational Flow of Dilute Polymer Solutions : Estimation of The Elongational Stresses by Utilizing Pressure Drops with Orifice Flows

    OpenAIRE

    福冨, 清; 長谷川, 富市; Fukutomi, Kiyoshi; Hasegawa, Tomiichi

    1988-01-01

    By assuming a uniformly converging radial flow on the upstream side of an orifice and integrating the equation of motion, an expression was derived to estimate elongational stresses for dilute polymer solutions at the orifice exit from pressure drops between the upstream and downstream of the orifice. The expression shown that the dilute polymer solutions usually give lower values of pressure drop than the solvent (water) does. An experiment was carried out to obtain the pressure drops for th...

  8. 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.

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

    Science.gov (United States)

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

    2015-10-26

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

  10. Link technologies and BlackBerry mobile health (mHealth) solutions: a review.

    Science.gov (United States)

    Adibi, Sasan

    2012-07-01

    The number of wearable wireless sensors is expected to grow to 400 million by the year 2014, while the number of operational mobile subscribers has already passed the 5.2 billion mark in 2011. This growth results in an increasing number of mobile applications including: Machine-to-Machine (M2M) communications, Electronic-Health (eHealth), and Mobile-Health (mHealth). A number of emerging mobile applications that require 3G and 4G mobile networks for data transport relate to telemedicine, including establishing, maintaining, and transmitting health-related information, research, education, and training. This review paper takes a closer look at these applications, specifically with regard to the healthcare industry and their underlying link technologies. The authors believe that the BlackBerry platform and the associated infrastructure (i.e., BlackBerry Enterprise Server) is a logical and practical solution for eHealth, mHealth, sensor and M2M deployments, which are considered in this paper.

  11. Investigation of cross-linking characteristics of novel hole-transporting materials for solution-processed phosphorescent OLEDs

    Science.gov (United States)

    Lee, Jaemin; Ameen, Shahid; Lee, Changjin

    2016-04-01

    After the success of commercialization of the vacuum-evaporated organic light-emitting diodes (OLEDs), solutionprocessing or printing of OLEDs are currently attracting much research interests. However, contrary to various kinds of readily available vacuum-evaporable OLED materials, the solution-processable OLED materials are still relatively rare. Hole-transporting layer (HTL) materials for solution-processed OLEDs are especially limited, because they need additional characteristics such as cross-linking to realize multilayer structures in solution-processed OLEDs, as well as their own electrically hole-transporting characteristics. The presence of such cross-linking characteristics of solutionprocessable HTL materials therefore makes them more challenging in the development stage, and also makes them essence of solution-processable OLED materials. In this work, the structure-property relationships of thermally crosslinkable HTL materials were systematically investigated by changing styrene-based cross-linking functionalities and modifying the carbazole-based hole-transporting core structures. The temperature dependency of the cross-linking characteristics of the HTL materials was systematically investigated by the UV-vis. absorption spectroscopy. The new HTL materials were also applied to green phosphorescent OLEDs, and their device characteristics were also investigated based on the chemical structures of the HTL materials. The device configuration was [ITO / PEDOT:PSS / HTL / EML / ETL / CsF / Al]. We found out that the chemical structures of the cross-linking functionalities greatly affect not only the cross-linking characteristics of the resultant HTL materials, but also the resultant OLED device characteristics. The increase of the maximum luminance and efficiency of OLEDs was evident as the cross-linking temperature decreases from higher than 200°C to at around 150°C.

  12. Nanosecond laser-induced periodic surface structuring of cross-linked azo-polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Berta, Marco, E-mail: marco.berta@univ-amu.fr [Aix Marseille Université, CNRS, ICR (Institut de Chimie Radicalaire) UMR 7273, 13397 Marseille Cedex 20 (France); Biver, Émeric [Aix Marseille Université, CNRS, LP3 UMR 7341, 13288 Marseille (France); Maria, Sébastien; Phan, Trang N.T. [Aix Marseille Université, CNRS, ICR (Institut de Chimie Radicalaire) UMR 7273, 13397 Marseille Cedex 20 (France); D’Aleo, Anthony; Delaporte, Philippe; Fages, Frederic [Aix Marseille Université, CNRS, CINaM UMR 7325, 13288 Marseille (France); Gigmes, Didier [Aix Marseille Université, CNRS, ICR (Institut de Chimie Radicalaire) UMR 7273, 13397 Marseille Cedex 20 (France)

    2013-10-01

    In this work we discuss the response to laser ablation of a poly(4-vinylbenzyl azide-random-methyl methacrylate) (p((S-N{sub 3})-r-MMA)) random copolymer. This material is cross-linkable thermally and upon exposure to UV light, and on cross-linked films the irradiation with a 248 nm ns KrF laser induces the formation of laser induced periodical surface structure (LIPSS). The LIPSS morphology is dependent on the amount of 4-vinylbenzyl azide (S-N{sub 3}) groups in the pristine copolymer. We propose a crosslinking mechanism based on the scission of azide with formation of azo groups and we discuss the possible relationship between this chemical modifications and the formation of ripples on the bottom of laser ablation cavities.

  13. Nanosecond laser-induced periodic surface structuring of cross-linked azo-polymer films

    Science.gov (United States)

    Berta, Marco; Biver, Émeric; Maria, Sébastien; Phan, Trang N. T.; D'Aleo, Anthony; Delaporte, Philippe; Fages, Frederic; Gigmes, Didier

    2013-10-01

    In this work we discuss the response to laser ablation of a poly(4-vinylbenzyl azide-random-methyl methacrylate) (p((S-N3)-r-MMA)) random copolymer. This material is cross-linkable thermally and upon exposure to UV light, and on cross-linked films the irradiation with a 248 nm ns KrF laser induces the formation of laser induced periodical surface structure (LIPSS). The LIPSS morphology is dependent on the amount of 4-vinylbenzyl azide (S-N3) groups in the pristine copolymer. We propose a crosslinking mechanism based on the scission of azide with formation of azo groups and we discuss the possible relationship between this chemical modifications and the formation of ripples on the bottom of laser ablation cavities.

  14. Highly stable CO2/N2 and CO2/CH4 selectivity in hyper-cross-linked heterocyclic porous polymers.

    Science.gov (United States)

    Saleh, Muhammad; Lee, Han Myoung; Kemp, K Christian; Kim, Kwang S

    2014-05-28

    The largest obstacles for landfill/flue gas separation using microporous materials are small adsorption values and low selectivity ratios. This study demonstrates that these adsorption and selectivity challenges can be overcome by utilizing a series of hyper-cross-linked heterocyclic polymer networks. These microporous organic polymers (MOPs) were synthesized in a single step by inexpensive Friedel-Crafts-catalyzed reactions using dimethoxymethane as an external linker. The amorphous networks show moderate Brunauer-Emmett-Teller surface areas up to 1022 m(2) g(-1), a narrow pore size distribution in the range from 6 to 8 Å, and high physicochemical stability. Owing to the presence of the heteroatomic pore surfaces in the networks, they exhibit maximum storage capacities for CO2 of 11.4 wt % at 273 K and 1 atm. Additionally, remarkable selectivity ratios for CO2 adsorption over N2 (100) and CH4 (15) at 273 K were obtained. More importantly, as compared with any other porous materials, much higher selectivity for CO2/N2 (80) and CO2/CH4 (15) was observed at 298 K, showing that these selectivity ratios remain high at elevated temperature. The very high CO2/N2 selectivity values are ascribed to the binding affinity of abundantly available electron-rich basic heteroatoms, high CO2 isoteric heats of adsorption (49-38 kJ mol(-1)), and the predominantly microporous nature of the MOPs. Binding energies calculated using the high level of ab initio theory showed that the selectivity is indeed attributed to the heteroatom-CO2 interactions. By employing an easy and economical synthesis procedure these MOPs with high thermochemical stability are believed to be a promising candidate for selective CO2 capture.

  15. [Exposure to mineral oils at worksites and novel solutions for polymer protective materials in selected personal protective equipment].

    Science.gov (United States)

    Krzemińska, Sylwia; Irzmańska, Emilia

    2011-01-01

    Exposure of workers to health hazards due to contact with mineral oils occurs primarily in the chemical, petrochemical, machine-building, metallurgic and car industries. Under worksite conditions, the respiratory system and the skin are the primary routes of entry of mineral oils into the human body. Long-term exposure of the skin to oily substances may lead not only to irritation and allergic lesions. The studies conducted in this area have confirmed a significant increase in the incidence of skin cancers in persons chronically exposed to mineral oils. Protection of workers' health at worksites associated with the risk of contact with mineral oils requires, in addition to collective protective and organizational solutions, personal protective equipment with appropriate protection and utility parameters confirmed by laboratory tests. The essential preventive measures include protection of the human skin by means of appropriate protective clothing and gloves, which provide an effective barrier against a wide spectrum of chemical compounds present in mineral oils. Knowledge of polymer materials is the prerequisite for designing more and more effective and functional protective clothing and gloves. Studies aimed at obtaining higher levels of skin protection against varied toxic substances, including mineral oils, have been conducted, among others, to develop modern glove and clothing materials ensuring resistance to oils. The rapid progress of nanotechnology and the use of nanoadditives in polymer materials has made it possible to undertake works aimed at developing modern polymer nanostructures designed for construction of oil-resistant protective clothing and gloves. In this review paper the authors have presented the current knowledge of polymer materials, from traditional ones to polymer nanostructures, used in personal equipment protecting against mineral oils.

  16. The Research of Biomedical Intelligent Polymer Materials

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi-bin; CHEN Yuan-wei; TANG Chang-wei; QIU Kai; LUO Juan; XU Cheng-yin; WAN Chang-xiu

    2004-01-01

    The properties of biomedical intelligent polymer materials can be changed obviously when there is a little physical or chemical change caused by external condition. They are in the forms of solids, solutions and the polymers on the surface of carrier, and include water solution of hydrophilic polymers, cross-linking hydrophilic polymers(i.e. hydrogels) and the polymers on the surface of carrier. The environmental stimulating factors are temperature, pH value, composition of solution, ionic intention, light intention, electric field, stress field and magnetic field etc.. The properties of intelligent polymer are those of phase, photics, mechanics, electric field, surface energy,reaction ratio, penetrating ratio and recognition etc..Stimulation-response of intelligent water-soluble polymerWater-soluble intelligent polymer can be separated out from solution under special external condition. It can be used as the switch of temperature or pH indicator. When water-soluble intelligent polymer is mixed with soluble-enzyme matter or cell suspension, the polymer can bring phase separation and react with soluble-enzyme matter or cell membrane through accepting some external stimulation. Other water-soluble intelligent polymer is that can make the main chemical group of some natural biomolecular recognition sequence section to arrange on skeleton of polymer at random. It is the same ratio as natural biomolecules.Stimulation-response of intelligent polymer of carrier surface Intelligent polymer can be fixed on the surface of solid polymer carrier through chemical grafting or physical adsorption. When the external conditions are changed, the thickness, humidity and electric field of the surface layer will be changed. Intelligent polymer can be preparated the permanence switch by precipitating into the hole of porous surface, and it can control on-off state of the hole. When protein or cell interacts with intelligent polymer surface to be placed in to open or close, they can be

  17. Enhancing the efficiency of solution-processed polymer:colloidal nanocrystal hybrid photovoltaic cells using ethanedithiol treatment.

    Science.gov (United States)

    Zhou, Renjia; Stalder, Romain; Xie, Dongping; Cao, Weiran; Zheng, Ying; Yang, Yixing; Plaisant, Marc; Holloway, Paul H; Schanze, Kirk S; Reynolds, John R; Xue, Jiangeng

    2013-06-25

    Advances in colloidal inorganic nanocrystal synthesis and processing have led to the demonstration of organic-inorganic hybrid photovoltaic (PV) cells using low-cost solution processes from blends of conjugated polymer and colloidal nanocrystals. However, the performance of such hybrid PV cells has been limited due to the lack of control at the complex interfaces between the organic and inorganic hybrid active materials. Here we show that the efficiency of hybrid PV devices can be significantly enhanced by engineering the polymer-nanocrystal interface with proper chemical treatment. Using two different conjugated polymers, poly(3-hexylthiophene) (P3HT) and poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']-dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT), we show that treating the polymer:nanocrystal hybrid film in an ethanedithiol-containing acetonitrile solution can increase the efficiency of the hybrid PV devices by 30-90%, and a maximum power conversion efficiency of 5.2 ± 0.3% was obtained in the PCPDTBT:CdSe devices at 0.2 sun (AM 1.5G), which was slightly reduced to 4.7 ± 0.3% at 1 sun. The ethanedithiol treatment did not result in significant changes in the morphology and UV-vis optical absorption of the hybrid thin films; however, infrared absorption, NMR, and X-ray photoelectron spectroscopies revealed the effective removal of organic ligands, especially the charged phosphonic acid ligands, from the CdSe nanorod surface after the treatment, accompanied by the possible monolayer passivation of nanorod surfaces with Cd-thiolates. We attribute the hybrid PV cell efficiency increase upon the ethanedithiol treatment to the reduction in charge and exciton recombination sites on the nanocrystal surface and the simultaneous increase in electron transport through the hybrid film.

  18. Molecular dynamics simulation of cross-linked urea-formaldehyde polymers for self-healing nanocomposites: prediction of mechanical properties and glass transition temperature.

    Science.gov (United States)

    Arab, Behrouz; Shokuhfar, Ali

    2013-11-01

    Urea-formaldehyde polymers, which are utilized in the adhesives industry, have recently been shown to be suitable materials for synthesizing micro/nanocapsules for use in self-healing (nano)composites. In this study, molecular dynamics was employed to simulate the process in which urea and formaldehyde are cross-linked via methylene and ether cross linkers, and to study the structure and mechanical/thermal properties of simulated poly(urea-formaldehyde)s (PUFs). The elastic stiffness constants of the simulated materials were calculated using the constant-strain (static) method. A temperature cycle was applied to the cross-linked PUFs, and the glass transition behavior of each material was investigated through the mean squared displacement (MSD) and temperature evolution of the energy and the specific volume of the polymer. The simulation results confirmed that there was considerable improvement in the properties of the poly(UF) materials upon cross linking. The radial distribution function was also used to study the local structures of the polymers, and this revealed that increasing the temperature and cross linking density results in a significant drop in hydrogen bonding intensity in the cross-linked PUF systems.

  19. FLUORESCENCE PROBING OF THE FORMATION OF HYDROPHOBIC MICRODOMAINS BY CROSS-LINKED POLY(ALKYLMETHYLDIALLYLAMMONIUM BROMIDES) IN AQUEOUS-SOLUTION

    NARCIS (Netherlands)

    WANG, GJ; ENGBERTS, J B F N

    Pyrene has been used as a fluorescence probe to investigate the conformational behavior of cross-linked poly(alkylmethyldiallylammonium bromides) in aqueous solutions. Binding of pyrene to hydrophobic microdomains, formed by the polysoaps, is reflected by a change in the ratio I-1/I-3 of the

  20. Adsorption of phenolic compounds from aqueous solutions by aminated hypercrosslinked polymers

    Institute of Scientific and Technical Information of China (English)

    JIANG Zhen-mao; LI Ai-min; CAI Jian-guo; WANG Chun; ZHANG Quan-xin

    2007-01-01

    Two novel polymers (NJ- 1 and NJ-2) were synthesized by chemically modified a hypercrosslinked polymer NJ-0 with dimethylamine and trimethylamine, respectively. The comparison of the adsorption properties of the three polymers toward phenol, resorcin and phloroglucin was made. The study focused on the static equilibrium adsorption behaviors and the adsorption thermodynamics.Freundlich equation was found to fit the adsorption results well. The effect of amino groups introduced onto the surface of the resin and the structure of phenolic compounds on the adsorption were also studied. The hydrogen-bonding interaction and electrostatic interaction could happen between the amino groups and the adsorbates. The adsorption impetus increased as quantity of hydroxyl groups increased, but the adsorption capacity decreased due to the drop of the matching degree of the aperture of resins and the diameter of adsorbate molecules.

  1. 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.

  2. Mass and Heat Diffusion in Ternary Polymer Solutions: A Classical Irreversible Thermodynamics Approach

    CERN Document Server

    Es-haghi, S Shams

    2016-01-01

    Governing equations for evolution of concentration and temperature in three-component systems were derived in the framework of classical irreversible thermodynamics using Onsager variational principle and were presented for solvent/solvent/polymer and solvent/polymer/polymer systems. The derivation was developed from the Gibbs equation of equilibrium thermodynamics using the local equilibrium hypothesis, Onsager reciprocal relations and Prigogine theorem for systems in mechanical equilibrium. It was shown that the details of mass and heat diffusion phenomena in a ternary system are completely expressed by a 3x3 matrix whose entries are mass diffusion coefficients (4 entries), thermal diffusion coefficients (2 entries) and three entries that describe the evolution of heat in the system. The entries of the diffusion matrix are related to the elements of Onsager matrix that are bounded by some constraints to satisfy the positive definiteness of entropy production in the system. All the elements of diffusion matr...

  3. Antimicrobial Polymers in Solution and on Surfaces: Overview and Functional Principles

    Directory of Open Access Journals (Sweden)

    Felix Siedenbiedel

    2012-01-01

    Full Text Available The control of microbial infections is a very important issue in modern society. In general there are two ways to stop microbes from infecting humans or deteriorating materials—disinfection and antimicrobial surfaces. The first is usually realized by disinfectants, which are a considerable environmental pollution problem and also support the development of resistant microbial strains. Antimicrobial surfaces are usually designed by impregnation of materials with biocides that are released into the surroundings whereupon microbes are killed. Antimicrobial polymers are the up and coming new class of disinfectants, which can be used even as an alternative to antibiotics in some cases. Interestingly, antimicrobial polymers can be tethered to surfaces without losing their biological activity, which enables the design of surfaces that kill microbes without releasing biocides. The present review considers the working mechanisms of antimicrobial polymers and of contact-active antimicrobial surfaces based on examples of recent research as well as on multifunctional antimicrobial materials.

  4. Cholesterol modification of (Bio)polymers using UV-Vis traceable chemistry in aqueous solutions.

    Science.gov (United States)

    Rasmussen, Kasper F; Smith, Anton A A; Ruiz-Sanchis, Pau; Edlund, Katrine; Zelikin, Alexander N

    2014-01-01

    Cholesterol modification of synthetic and biological polymers is achieved using of thiocholesterol (TC) and thiol-disulfide exchange. TC is reacted with Ellman's reagent to produce a mixed disulfide (TC-ER) which is activated towards thiol-disulfide exchange. TC-ER is used to obtain an inclusion complex with methyl-β-cyclodextrin, which is then employed to achieve cholesterol functionalization of a model peptide, synthetic polymers, and physical hydrogels based on poly(vinyl alcohol). It is anticipated that the established techniques will significantly broaden the use of cholesterol in bio- and nanotechnology and specifically biomedicine.

  5. Direct measurement of the intermolecular forces confining a single molecule in an entangled polymer solution.

    Science.gov (United States)

    Robertson, Rae M; Smith, Douglas E

    2007-09-21

    We use optical tweezers to directly measure the intermolecular forces acting on a single polymer imposed by surrounding entangled polymers (115 kbp DNA, 1 mg/ml). A tubelike confining field was measured in accord with the key assumption of reptation models. A time-dependent harmonic potential opposed transverse displacement, in accord with recent simulation findings. A tube radius of 0.8 microm was determined, close to the predicted value (0.5 microm). Three relaxation modes (approximately 0.4, 5, and 34 s) were measured following transverse displacement, consistent with predicted relaxation mechanisms.

  6. Corneal Collagen Cross-Linking with Hypoosmolar Riboflavin Solution in Keratoconic Corneas

    Directory of Open Access Journals (Sweden)

    Shaofeng Gu

    2014-01-01

    Full Text Available Purpose. To report the 12-month outcomes of corneal collagen cross-linking (CXL with a hypoosmolar riboflavin and ultraviolet-A (UVA irradiation in thin corneas. Methods. Eight eyes underwent CXL using a hypoosmolar riboflavin solution after epithelial removal. The corrected distance visual acuity (CDVA, manifest refraction, the mean thinnest corneal thickness (MTCT, and the endothelial cell density (ECD were evaluated before and 6 and 12 months after CXL. Results. The MTCT was 413.9 ± 12.4 μm before treatment and reduced to 381.1 ± 7.3 μm after the removal of the epithelium. After CXL, the thickness decreased to 410.3 ± 14.5 μm at the last follow-up. Before treatment, the mean K-value of the apex of the keratoconus corneas was 58.7 ± 3.5 diopters and slightly decreased (57.7 ± 4.9 diopters at 12 months. The mean CDVA was 0.54 ± 0.23 logarithm of the minimal angle of resolution before treatment and increased to 0.51 ± 0.21 logarithm at the last follow-up. The ECD was 2731.4 ± 191.8 cells/mm2 before treatment and was 2733.4 ± 222.6 cells/mm2 at 12 months after treatment. Conclusions. CXL with a hypoosmolar riboflavin in thin corneas seems to be a promising method for keratoconic eyes with the mean thinnest corneal thickness less than 400 μm without epithelium.

  7. Thiolated and S-protected hydrophobically modified cross-linked poly(acrylic acid)--a new generation of multifunctional polymers.

    Science.gov (United States)

    Bonengel, Sonja; Haupstein, Sabine; Perera, Glen; Bernkop-Schnürch, Andreas

    2014-10-01

    The aim of this study was to create a novel multifunctional polymer by covalent attachment of l-cysteine to the polymeric backbone of hydrophobically modified cross-linked poly(acrylic acid) (AC1030). Secondly, the free thiol groups of the resulting thiomer were activated using 2-mercaptonicotinic acid (2-MNA) to provide full reactivity and stability. Within this study, 1167.36 μmol cysteine and 865.72 μmol 2-MNA could be coupled per gram polymer. Studies evaluating mucoadhesive properties revealed a 4-fold extended adherence time to native small intestinal mucosa for the thiomer (AC1030-cysteine) as well as an 18-fold prolonged adhesion for the preactivated thiomer (AC1030-Cyst-2-MNA) compared to the unmodified polymer. Modification of the polymer led to a higher tablet stability concerning the thiomer and the S-protected thiomer, but a decelerated water uptake could be observed only for the preactivated thiomer. Neither the novel conjugates nor the unmodified polymer showed severe toxicity on Caco-2 cells. Evaluation of emulsification capacity proofed the ability to incorporate lipophilic compounds like medium chain triglycerides and the preservation of the emulsifying properties after the modifications. According to these results thiolated AC1030 as well as the S-protected thiolated polymer might provide a promising tool for solid and semisolid formulations in pharmaceutical development.

  8. 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)

  9. 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 o

  10. 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

  11. 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 o

  12. Classical and recent free-volume models for polymer solutions: A comparative evaluation

    DEFF Research Database (Denmark)

    Radfarnia, H.R.; Kontogeorgis, Georgios; Ghotbi, C.

    2007-01-01

    to improve the performance of a recent model, the so-called Freed-FV First, we propose a modification of the Freed-FV model accounting for the anomalous free-volume behavior of aqueous systems (unlike the other solvents, water has a lower free-volume percentage than polymers). The results predicted...

  13. Extensional Rheology Experiment Developed to Investigate the Rheology of Dilute Polymer Solutions in Microgravity

    Science.gov (United States)

    Logsdon, Kirk A.

    2001-01-01

    A fundamental characteristic of fluid is viscosity; that is, the fluid resists forces that cause it to flow. This characteristic, or parameter, is used by manufacturers and end-users to describe the physical properties of a specific material so that they know what to expect when a material, such as a polymer, is processed through an extruder, a film blower, or a fiber-spinning apparatus. Normally, researchers will report a shear viscosity that depends on the rate of an imposed shearing flow. Although this type of characterization is sufficient for some processes, simple shearing experiments do not provide a complete picture of what a processor may expect for all materials. Extensional stretching flows are common in many polymer-processing operations such as extrusion, blow molding, and fiber spinning. Therefore, knowledge of the complete rheological (ability to flow and be deformed) properties of the polymeric fluid being processed is required to accurately predict and account for the flow behavior. In addition, if numerical simulations are ever able to serve as a priori design tools for optimizing polymer processing operations such as those described above, an accurate knowledge of the extensional viscosity of a polymer system and its variation with temperature, concentration, molecular weight, and strain rate is critical.

  14. Optimum design of amphiphilic polymers bearing hydrophobic groups for both cell surface ligand presentation and intercellular cross-linking.

    Science.gov (United States)

    Takeo, Masafumi; Li, Cuicui; Matsuda, Masayoshi; Nagai, Hiroko; Hatanaka, Wataru; Yamamoto, Tatsuhiro; Kishimura, Akihiro; Mori, Takeshi; Katayama, Yoshiki

    2015-01-01

    Amphiphilic polymers bearing hydrophobic alkyl groups are expected to be applicable for both ligand presentation on the cell surface and intercellular crosslinking. To explore the optimum design for each application, we synthesized eight different acyl-modified dextrans with varying molecular weight, alkyl length, and alkyl modification degree. We found that the behenate-modified polymers retained on the cell surface longer than the palmitate-modified ones. Since the polymers were also modified with biotin, streptavidin can be presented on the cell surface through biotin-streptavidin recognition. The duration of streptavidin on the cell surface is longer in the behenate-modified polymer than the palmitate-modified one. As for the intercellular crosslinking, the palmitate-modified polymers were more efficient than the behenate-modified polymers. The findings in this research will be helpful to design the acyl-modified polymers for the cell surface engineering.

  15. 疏水缔合聚合物的合成及溶液性质研究%Synthesis and Solution Properties of Hydrophobic Associating Polymers

    Institute of Scientific and Technical Information of China (English)

    任鲲; 姜桂元; 徐春明; 林梅钦

    2005-01-01

    Acrylamide/2-acrylamido alkane sulfonic acid hydrophobic associating copolymers were synthesized by micellar copolymerization. Effects of hydrophobe content, polymer concentration, salinity and surfactant on rheological behavior of copolymers were investigated and the conformation of polymers in solution was studied by means of environmental scanning electronic microscopy and dynamic light scattering. The experimental results showed that in the dilute regime the hydrophobic parts could interact intramolecularly, while in the regime where the polymer concentration was higher than the critical association concentration, intermolecular hydrophobic association became predominant. Within the limit of the solubility, the critical association concentration of the polymer decreased with the increase of the salinity. The experimental results of the solution conformation indicated the presence of the three-dimensional network structure in deionized water and the size of the mesh in the network varied with the polymer concentration. In NaCl solution, above the critical association concentration, an increase in polymer concentration enhanced the intermolecular association and also enlarged the hydrodynamic radius. It would result in the improvement of the thickening power of polymers.

  16. Highly branched and loop-rich gels via formation of metal-organic cages linked by polymers.

    Science.gov (United States)

    Zhukhovitskiy, Aleksandr V; Zhong, Mingjiang; Keeler, Eric G; Michaelis, Vladimir K; Sun, Jessie E P; Hore, Michael J A; Pochan, Darrin J; Griffin, Robert G; Willard, Adam P; Johnson, Jeremiah A

    2016-01-01

    Gels formed via metal-ligand coordination typically have very low branch functionality, f, as they consist of ∼2-3 polymer chains linked to single metal ions that serve as junctions. Thus, these materials are very soft and unable to withstand network defects such as dangling ends and loops. We report here a new class of gels assembled from polymeric ligands and metal-organic cages (MOCs) as junctions. The resulting 'polyMOC' gels are precisely tunable and may feature increased branch functionality. We show two examples of such polyMOCs: a gel with a low f based on a M2L4 paddlewheel cluster junction and a compositionally isomeric one of higher f based on a M12L24 cage. The latter features large shear moduli, but also a very large number of elastically inactive loop defects that we subsequently exchanged for functional ligands, with no impact on the gel's shear modulus. Such a ligand substitution is not possible in gels of low f, including the M2L4-based polyMOC.

  17. Compressive cyclic ratcheting and fatigue of synthetic, soft biomedical polymers in solution.

    Science.gov (United States)

    Miller, Andrew T; Safranski, David L; Smith, Kathryn E; Guldberg, Robert E; Gall, Ken

    2016-02-01

    The use of soft, synthetic materials for the replacement of soft, load-bearing tissues has been largely unsuccessful due to a lack of materials with sufficient fatigue and wear properties, as well as a lack of fundamental understanding on the relationship between material structure and behavior under cyclic loads. In this study, we investigated the response of several soft, biomedical polymers to cyclic compressive stresses under aqueous conditions and utilized dynamic mechanical analysis and differential scanning calorimetry to evaluate the role of thermo-mechanical transitions on such behavior. Studied materials include: polycarbonate urethane, polydimethylsiloxane, four acrylate copolymers with systematically varied thermo-mechanical transitions, as well as bovine meniscal tissue for comparison. Materials showed compressive moduli between 2.3 and 1900MPa, with polycarbonate urethane (27.3MPa) matching closest to meniscal tissue (37.0MPa), and also demonstrated a variety of thermo-mechanical transition behaviors. Cyclic testing resulted in distinct fatigue-life curves, with failure defined as either classic fatigue fracture or a defined increased in maximum strain due to ratcheting. Our study found that polymers with sufficient dissipation mechanisms at the testing temperature, as evidenced by tan delta values, were generally tougher than those with less dissipation and exhibited ratcheting rather than fatigue fracture much like meniscal tissue. Strain recovery tests indicated that, for some toughened polymers, the residual strain following our cyclic loading protocol could be fully recovered. The similarity in ratcheting behavior, and lack of fatigue fracture, between the meniscal tissue and toughened polymers indicates that such polymers may have potential as artificial soft tissue.

  18. Impact of polymer conformation on the crystal growth inhibition of a poorly water-soluble drug in aqueous solution.

    Science.gov (United States)

    Schram, Caitlin J; Beaudoin, Stephen P; Taylor, Lynne S

    2015-01-01

    Poor aqueous solubility is a major hindrance to oral delivery of many emerging drugs. Supersaturated drug solutions can improve passive absorption across the gastrointestinal tract membrane as long as crystallization can be inhibited, enhancing the delivery of such poorly soluble therapeutics. Polymers can inhibit crystallization and prolong supersaturation; therefore, it is desirable to understand the attributes which render a polymer effective. In this study, the conformation of a polymer adsorbed to a crystal surface and its impact on crystal growth inhibition were investigated. The crystal growth rate of a poorly soluble pharmaceutical compound, felodipine, was measured in the presence of hydroxypropyl methylcellulose acetate succinate (HPMCAS) at two different pH conditions: pH 3 and pH 6.8. HPMCAS was found to be a less effective growth rate inhibitor at pH 3, below its pKa. It was expected that the ionization state of HPMCAS would most likely influence its conformation at the solid-liquid interface. Further investigation with atomic force microscopy (AFM) revealed significant differences in the conformation of HPMCAS adsorbed to felodipine at the two pH conditions. At pH 3, HPMCAS formed coiled globules on the surface, whereas at pH 6.8, HPMCAS adsorbed more uniformly. Thus, it appeared that the reduced effectiveness of HPMCAS at pH 3 was directly related to its conformation. The globule formation leaves many felodipine growth sites open and available for growth units to attach, rendering the polymer less effective as a growth rate inhibitor.

  19. Low-Temperature All-Solution-Processed Transparent Silver Nanowire-Polymer/AZO Nanoparticles Composite Electrodes for Efficient ITO-Free Polymer Solar Cells.

    Science.gov (United States)

    Zhang, Xiaoqin; Wu, Jiang; Wang, Jiantai; Yang, Qingqing; Zhang, Baohua; Xie, Zhiyuan

    2016-12-21

    We present a kind of all-solution-processed transparent conductive film comprising of silver nanowire (AgNW), polyvinyl butyral (PVB), and Al-doped ZnO nanoparticles (AZO NPs) composite (APA) by layer-by-layer blade-coating on glass substrate at low temperature. This kind of transparent APA film exhibits high transmittance at a wide range of 400-700 nm. The sheet resistance of the APA film can be as low as 21 Ω sq(-1) with transmittance over 94% at 550 nm. The introduction of PVB significantly improves the APA composite adhesion to glass substrate. The overlaid coating of AZO NPs not only reduces the sheet resistance but also improves the ambient and thermal stability of the APA film. This highly conductive and transparent APA film on glass substrate is employed as the bottom electrode to fabricate high-efficiency polymer solar cells (PSCs). A power conversion efficiency of 8.98% is achieved for the PBDTTT-EFT:PC71BM PSCs employing the APA composite as transparent bottom electrode, close to 9.54% of the control device fabricated on the commercial indium tin oxide substrate. As it can be easily prepared with all-solution-processed blade-coating method at low temperature, this kind of AgNW-based composite film is promising to integrate with roll-to-roll manufacturing of flexible PSCs.

  20. From the Solution Processing of Hydrophilic Molecules to Polymer-Phthalocyanine Hybrid Materials for Ammonia Sensing in High Humidity Atmospheres

    Science.gov (United States)

    Gaudillat, Pierre; Jurin, Florian; Lakard, Boris; Buron, Cédric; Suisse, Jean-Moïse; Bouvet, Marcel

    2014-01-01

    We have prepared different hybrid polymer-phthalocyanine materials by solution processing, starting from two sulfonated phthalocyanines, s-CoPc and CuTsPc, and polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), poly(acrylic acid-co-acrylamide) (PAA-AM), poly(diallyldimethylammonium chloride) (PDDA) and polyaniline (PANI) as polymers. We also studied the response to ammonia (NH3) of resistors prepared from these sensing materials. The solvent casted films, prepared from s-CoPc and PVP, PEG and PAA-AM, were highly insulating and very sensitive to the relative humidity (RH) variation. The incorporation of s-CoPc in PDDA by means of layer-by-layer (LBL) technique allowed to stabilize the film, but was too insulating to be interesting. We also prepared PANI-CuTsPc hybrid films by LBL technique. It allowed a regular deposition as evidenced by the linear increase of the absorbance at 688 nm as a function of the number of bilayers. The sensitivity to ammonia (NH3) of PANi-CuTsPc resistors was very high compared to that of individual materials, giving up to 80% of current decrease when exposed to 30 ppm NH3. Contrarily to what happens with neutral polymers, in PANI, CuTsPc was stabilized by strong electrostatic interactions, leading to a stable response to NH3, whatever the relative humidity in the range 10%–70%. Thus, the synergy of PANI with ionic macrocycles used as counteranions combined with their simple aqueous solution processing opens the way to the development of new gas sensors capable of operating in real world conditions. PMID:25061841

  1. From the solution processing of hydrophilic molecules to polymer-phthalocyanine hybrid materials for ammonia sensing in high humidity atmospheres.

    Science.gov (United States)

    Gaudillat, Pierre; Jurin, Florian; Lakard, Boris; Buron, Cédric; Suisse, Jean-Moïse; Bouvet, Marcel

    2014-07-24

    We have prepared different hybrid polymer-phthalocyanine materials by solution processing, starting from two sulfonated phthalocyanines, s-CoPc and CuTsPc, and polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), poly(acrylic acid-co-acrylamide) (PAA-AM), poly(diallyldimethylammonium chloride) (PDDA) and polyaniline (PANI) as polymers. We also studied the response to ammonia (NH3) of resistors prepared from these sensing materials. The solvent casted films, prepared from s-CoPc and PVP, PEG and PAA-AM, were highly insulating and very sensitive to the relative humidity (RH) variation. The incorporation of s-CoPc in PDDA by means of layer-by-layer (LBL) technique allowed to stabilize the film, but was too insulating to be interesting. We also prepared PANI-CuTsPc hybrid films by LBL technique. It allowed a regular deposition as evidenced by the linear increase of the absorbance at 688 nm as a function of the number of bilayers. The sensitivity to ammonia (NH3) of PANi-CuTsPc resistors was very high compared to that of individual materials, giving up to 80% of current decrease when exposed to 30 ppm NH3. Contrarily to what happens with neutral polymers, in PANI, CuTsPc was stabilized by strong electrostatic interactions, leading to a stable response to NH3, whatever the relative humidity in the range 10%-70%. Thus, the synergy of PANI with ionic macrocycles used as counteranions combined with their simple aqueous solution processing opens the way to the development of new gas sensors capable of operating in real world conditions.

  2. From the Solution Processing of Hydrophilic Molecules to Polymer-Phthalocyanine Hybrid Materials for Ammonia Sensing in High Humidity Atmospheres

    Directory of Open Access Journals (Sweden)

    Pierre Gaudillat

    2014-07-01

    Full Text Available We have prepared different hybrid polymer-phthalocyanine materials by solution processing, starting from two sulfonated phthalocyanines, s-CoPc and CuTsPc, and polyvinylpyrrolidone (PVP, polyethylene glycol (PEG, poly(acrylic acid-co-acrylamide (PAA-AM, poly(diallyldimethylammonium chloride (PDDA and polyaniline (PANI as polymers. We also studied the response to ammonia (NH3 of resistors prepared from these sensing materials. The solvent casted films, prepared from s-CoPc and PVP, PEG and PAA-AM, were highly insulating and very sensitive to the relative humidity (RH variation. The incorporation of s-CoPc in PDDA by means of layer-by-layer (LBL technique allowed to stabilize the film, but was too insulating to be interesting. We also prepared PANI-CuTsPc hybrid films by LBL technique. It allowed a regular deposition as evidenced by the linear increase of the absorbance at 688 nm as a function of the number of bilayers. The sensitivity to ammonia (NH3 of PANi-CuTsPc resistors was very high compared to that of individual materials, giving up to 80% of current decrease when exposed to 30 ppm NH3. Contrarily to what happens with neutral polymers, in PANI, CuTsPc was stabilized by strong electrostatic interactions, leading to a stable response to NH3, whatever the relative humidity in the range 10%–70%. Thus, the synergy of PANI with ionic macrocycles used as counteranions combined with their simple aqueous solution processing opens the way to the development of new gas sensors capable of operating in real world conditions.

  3. Moving through the phase diagram: morphology formation in solution cast polymer-fullerene blend films for organic solar cells.

    Science.gov (United States)

    Schmidt-Hansberg, Benjamin; Sanyal, Monamie; Klein, Michael F G; Pfaff, Marina; Schnabel, Natalie; Jaiser, Stefan; Vorobiev, Alexei; Müller, Erich; Colsmann, Alexander; Scharfer, Philip; Gerthsen, Dagmar; Lemmer, Uli; Barrena, Esther; Schabel, Wilhelm

    2011-11-22

    The efficiency of organic bulk heterojunction solar cells strongly depends on the multiscale morphology of the interpenetrating polymer-fullerene network. Understanding the molecular assembly and the identification of influencing parameters is essential for a systematic optimization of such devices. Here, we investigate the molecular ordering during the drying of doctor-bladed polymer-fullerene blends on PEDOT:PSS-coated substrates simultaneously using in situ grazing incidence X-ray diffraction (GIXD) and laser reflectometry. In the process of blend crystallization, we observe the nucleation of well-aligned P3HT crystallites in edge-on orientation at the interface at the instant when P3HT solubility is crossed. A comparison of the real-time GIXD study at ternary blends with the binary phase diagrams of the drying blend film gives evidence of strong polymer-fullerene interactions that impede the crystal growth of PCBM, resulting in the aggregation of PCBM in the final drying stage. A systematic dependence of the film roughness on the drying time after crossing P3HT solubility has been shown. The highest efficiencies have been observed for slow drying at low temperatures which showed the strongest P3HT interchain π-π-ordering along the substrate surface. By adding the "unfriendly" solvent cyclohexanone to a chlorobenzene solution of P3HT:PCBM, the solubility can be crossed prior to the drying process. Such solutions exhibit randomly orientated crystalline structures in the freshly cast film which results in a large crystalline orientation distribution in the dry film that has been shown to be beneficial for solar cell performance.

  4. Solutions for lipophilic drugs: a biodegradable polymer acting as solvent, matrix, and carrier to solve drug delivery issues.

    Science.gov (United States)

    Asmus, Lutz R; Gurny, Robert; Möller, Michael

    2011-02-01

    The purpose of this study was to investigate the polyester hexylsubstituted poly(lactide) (hexPLA) as a possible solvent for lipophilic substances and excipient for pharmaceutical formulations. HexPLA is a biodegradable and semi-solid polymer, which allows the incorporation of active substances by simple mixing and local or systemic application to the patient through injection. The solvent behavior of hexPLA was investigated by adding the lipophilic dye Sudan III to the polymer matrix and optical monitoring of the dissolution process over time by microscopy. As a drug, the antipsychotic compound haloperidol was analyzed for its solubility in hexPLA of different molecular weights by preparing saturated solutions, and measuring the amount of incorporated drug with UV spectroscopy. The influence of the rate of solubilized to suspended drug on the burst release behavior of haloperidol from hexPLA-formulations was investigated in release tests. It is demonstrated that hexPLA dissolves both lipophilic substances, Sudan III and Haloperidol. In the molecular weight range between 2,000 g/mol and 10,000 g/mol, a lower molecular weight hexPLA resulted in a higher incorporation capacity for haloperidol. By changing from a suspension formulation of haloperidol to a solution formulation, the initial burst release established for classical PLA and PLGA systems could be minimized. HexPLA is shown to be a potent solvent and excipient for lipophilic drugs, allowing the initial burst of drug release to be modified and controlled.

  5. RESEARCH ON COHERENT STRUCTURES IN A MIXING LAYER OF THE FENE-P POLYMER SOLUTION

    Institute of Scientific and Technical Information of China (English)

    邵雪明; 林建忠; 余钊圣

    2001-01-01

    The evolution of the coherent structures in a two-dimensional time-developing mixing layer of the FENE-P fluids is examined numerically. By the means of an appropriate filtering for the polymer stress, some characteristics of the coherent structures at high b were obtained, which Azaiez and Homsy did not address. The results indicate that adding polymer to the Newtonian fluids will cause stronger vorticity diffusion, accompanied with weaker fundamental and subharmonical perturbations and slower rotational motion of neighboring vortices during pairing. This effect decreases with the Weissenberg number, but increases with b. In addition, the time when the consecutive rollers are completely coalesced into one delays in the viscoelastic mixing layer compared with the Newtonian one of the same total viscosity.

  6. Dissipated work in driven harmonic diffusive systems: General solution and application to stretching Rouse polymers

    Science.gov (United States)

    Speck, T.; Seifert, U.

    2005-02-01

    We study n-dimensional diffusive motion in an externally driven harmonic potential. For these systems the probability distribution of the applied work is a Gaussian. We give explicit expressions for its mean and variance, which are determined by a non-local integral kernel relating the time-derivatives of the applied forces. As illustrations, we specialize our results to dragging a colloidal particle through a viscous fluid and to stretching a Rouse polymer with different protocols.

  7. Biological destruction of polymer solutions used to improve oil bed output

    Energy Technology Data Exchange (ETDEWEB)

    Gareyshina, A.Z.; Gazizov, A.Sh.; Nazmutdinov, R.Ya.; Ozhiganova, G.U.; Yaus, L.I.

    1984-01-01

    A plan is presented and the results of studying biological destruction of polyacrylamide by fresh water microflora in dynamics. It is shown that polymer destruction as a result of the vital activity of microorganisms occurs most intensively in the first 1-1.5 months. During this period, the degree of destruction of polyacrylamide reaches 70-80%, which corresponds to a decrease in the average molecular mass 4-5-fold.

  8. 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.

  9. One-pot synthesis of ZnS/polymer composites in supercritical CO2-ethanol solution and their applications in degradation of dyes.

    Science.gov (United States)

    Xie, Yun; Zhang, Chengliang; Miao, Shiding; Liu, Zhimin; Ding, Kunlun; Miao, Zhenjiang; An, Guimin; Yang, Zhenzhong

    2008-02-01

    A facile method to decorate the polymeric hollow spheres with ZnS nanoparticles has been presented. In this method, the precursors, Zn(Ac)(2)H(2)O and CH(3)CSNH(2), were first adsorbed by the polymer substrate in supercritical CO(2)-ethanol solution at 35 degrees C. Followed by heating the mixture at 100 degrees C for 2 h, ZnS/polymer composites were obtained. The as-produced ZnS/polymer composites were characterized by means of IR spectra, X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy. It was demonstrated that crystalline ZnS nanoparticles with size of 3-5 nm were uniformly decorated on the polymer spheres under suitable conditions. The resultant ZnS/polymer composites exhibited high efficiency for degrading eosin B, methyl orange and methylene blue under UV light irradiation.

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

    Science.gov (United States)

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

    2016-06-21

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

  11. 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 (Mw/Mn) 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 D2O. 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.

  12. Laplacian spectra of recursive treelike small-world polymer networks: analytical solutions and applications.

    Science.gov (United States)

    Liu, Hongxiao; Zhang, Zhongzhi

    2013-03-21

    A central issue in the study of polymer physics is to understand the relation between the geometrical properties of macromolecules and various dynamics, most of which are encoded in the Laplacian spectra of a related graph describing the macrostructural structure. In this paper, we introduce a family of treelike polymer networks with a parameter, which has the same size as the Vicsek fractals modeling regular hyperbranched polymers. We study some relevant properties of the networks and show that they have an exponentially decaying degree distribution and exhibit the small-world behavior. We then study the Laplacian eigenvalues and their corresponding eigenvectors of the networks under consideration, with both quantities being determined through the recursive relations deduced from the network structure. Using the obtained recursive relations we can find all the eigenvalues and eigenvectors for the networks with any size. Finally, as some applications, we use the eigenvalues to study analytically or semi-analytically three dynamical processes occurring in the networks, including random walks, relaxation dynamics in the framework of generalized Gaussian structure, as well as the fluorescence depolarization under quasiresonant energy transfer. Moreover, we compare the results with those corresponding to Vicsek fractals, and show that the dynamics differ greatly for the two network families, which thus enables us to distinguish between them.

  13. Preparation of molecularly imprinted polymer nanoparticles for selective removal of fluoroquinolone antibiotics in aqueous solution.

    Science.gov (United States)

    Tan, Feng; Sun, Daming; Gao, Jinsuo; Zhao, Qian; Wang, Xiaochun; Teng, Fei; Quan, Xie; Chen, Jingwen

    2013-01-15

    In this study, novel molecularly imprinted polymer nanoparticles (nanoMCN@MIPs) were prepared by covalent grafting of ofloxacin-imprinted polymer onto the surface of mesoporous carbon nanoparticles (MCNs). SEM analyses indicated that the prepared nanoMCN@MIPs were almost uniform, and their geometrical mean diameter was about 230 nm. The sorption behaviors of the nanoMCN@MIPs including sorption kinetics and isotherms, effect of pH, ionic strength, and cross-reactivity were investigated in detail. The adsorption capacity of the nanoparticles for ofloxacin was 40.98 mg/g, with a selectivity factor of 2.6 compared to the nonimprinted polymer nanoparticles (nanoMCN@NIPs). The feasibility of removing fluoroquinolone antibiotics (FQs) from environmental waters with the nanoMCN@MIPs was demonstrated using sea water spiked with six typical FQs (ofloxacin, gatifloxacin, balofloxcacin, enrofloxacin, norfloxacin and sarafloxacin). The nanoMCN@MIPs could be reused at least five times with removal efficiency more than 90% except for norfloxacin. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Chemistry and physical properties of melt-processed and solution-cross-linked corn zein.

    Science.gov (United States)

    Sessa, David J; Mohamed, Abdellatif; Byars, Jeffrey A

    2008-08-27

    Corn zein was cross-linked with glutaraldehyde (GDA) using glacial acetic acid (HAc) as catalyst. The objectives are to evaluate the swelling characteristics of GDA cross-linked zein gels in water, ethanol, and their combinations. Similar formulations, upon solvent evaporation, form films. The mechanical properties of the films are compared to compression molded tensile bars from GDA melt-processed zein as a second objective. Chemistry of the cross-linking reaction was based on the aldehyde binding characteristics defined by use of fluorescence spectroscopy; sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) to demonstrate the cross-linking reaction; FTIR to observe absorption differences of the cross-linked product; differential scanning calorimetry, dynamic mechanical analysis and thermogravimetric analysis to assess thermal properties; and the use of Instron Universal Testing Machine to evaluate mechanical properties. A reaction mechanism for acid catalyzed GDA cross-linking of zein is proposed. Thermal and mechanical properties of tensile bars cut from either film or formed by compression molding were similar, where both showed increased tensile strengths, ductility and stiffness when compared with unmodified controls. Samples that were reacted with 8% GDA by weight based on weight of zein from either process retained their integrity when tensile bars from each were subjected to boiling water for 10 min or soaking in either water or HAc for 24 h. The melt-processed, cross-linked zein is a more environmentally friendly method that would eliminate the need for HAc recovery.

  15. Chelating fibers prepared with a wet spinning technique using a mixture of a viscose solution and a polymer ligand for the separation of metal ions in an aqueous solution.

    Science.gov (United States)

    Kagaya, Shigehiro; Miyazaki, Hiroyuki; Inoue, Yoshinori; Kato, Toshifumi; Yanai, Hideyuki; Kamichatani, Waka; Kajiwara, Takehiro; Saito, Mitsuru; Tohda, Koji

    2012-02-15

    Chelating fibers containing polymer ligands such as carboxymethylated polyallylamine, carboxymethylated polyethyleneimine, and a copolymer of diallylamine hydrochloride/maleic acid were prepared with a wet spinning technique using mixtures of a viscose solution and the polymer ligands. The chelating fibers obtained effectively adsorbed various metal ions, including Cd(II), Co(II), Cr(III), Cu(II), Fe(III), Mn(II), Ni(II), Pb(II), Ti(IV), and Zn(II). The metal ions adsorbed could be readily desorbed using 0.1 or 0.5 mol L(-1) HNO(3). The chelating fiber containing carboxymethylated polyallylamine was available for the separation of some metal ions in synthetic wastewater containing a large amount of Na(2)SO(4). The wet spinning technique using a solution containing a base polymer and a polymer ligand was quite simple and effective and would be applicable for preparing various chelating fibers.

  16. A Flexible 5G Wide Area Solution for TDD with Asymmetric Link Operation

    DEFF Research Database (Denmark)

    Pedersen, Klaus I.; Berardinelli, Gilberto; Frederiksen, Frank

    2017-01-01

    A flexible multi-service 5G wide area (WA) solution for time division duplex (TDD) operation is outlined in this article. In particular, the Associated frame design is in focus. Given the fundamental tradeoffs between capacity, coverage, latency, and reliability, a flexible solution that allows...

  17. Preparation and application of polymer inclusion membranes (PIMs) including alamine 336 for the extraction of metals from an aqueous solution: Priprava in uporaba membrane iz polimera (PIM) in alamina 336 za ločenje kovin iz vodnih raztopin:

    OpenAIRE

    2014-01-01

    Polymer inclusion membranes (PIMs) present an attractive approach for the separation of metals from an aqueous solution. The present study is about the application of Alamine 336 as an ion carrier in PIMs. The separation of copper (II), cobalt (II), nickel (II) and cadmium (II) from aqueous solutions with polymer inclusion membranes was investigated. PIMs are formed by casting a solution containing a carrier (extractant), a plasticizer and a base polymer, such as cellulose tri-acetate (CTA) o...

  18. Fluorescence Development of Latent Fingerprint with Conjugated Polymer Nanoparticles in Aqueous Colloidal Solution.

    Science.gov (United States)

    Chen, Hong; Ma, Rong-Liang; Chen, Yun; Fan, Li-Juan

    2017-02-08

    Poly(p-phenylenevinylene) (PPV) nanoparticles in aqueous colloidal solution have been prepared via a modified Wessling method, with the addition of surfactant. The fluorescent colloidal solution was used as the developing solution to develop the fingerprints on different substrates. The developing process was accomplished simply by immersing the substrates into developing solution and then taking out, followed by rinsing with deionized water. The initial study about the fingerprints on the adhesive tapes showed that the developing solution is very effective in fluorescence development on both fresh and aged visible fingerprints; and such an effect was negligibly affected by treating the fingerprints with water or other organic solvents, whether before developing or after. Further study on latent fingerprints (LFPs) demonstrated that PPV nanoparticles in colloidal solution have high sensitivity in developing fingerprints to give very clearly fluorescent patterns. At least 6 months of storage of the colloidal solution did not reduce the developing effect; and each developing solution (3.6 mg/mL, 5.0 mL) can be used to develop at least 30 fingerprints without sacrificing the legibility of the pattern. The preliminary mechanism investigation suggested that selectivity achieved toward the ridge of the fingerprint is very likely due to the affinity between PPV molecules and oily secretions of the fingerprints. Digital magnification of the developed fingerprints provided more details about the fingerprint.

  19. Ligase detection reaction for the analysis of point mutations using free-solution conjugate electrophoresis in a polymer microfluidic device.

    Science.gov (United States)

    Sinville, Rondedrick; Coyne, Jennifer; Meagher, Robert J; Cheng, Yu-Wei; Barany, Francis; Barron, Annelise; Soper, Steven A

    2008-12-01

    We have developed a new method for the analysis of low abundant point mutations in genomic DNA using a combination of an allele-specific ligase detection reaction (LDR) with free-solution conjugate electrophoresis (FSCE) to generate and analyze the genetic products. FSCE eliminates the need for a polymer sieving matrix by conjugating chemically synthesized polyamide "drag-tags" onto the LDR primers. The additional drag of the charge-neutral drag-tag breaks the linear scaling of the charge-to-friction ratio of DNA and enables size-based separations of DNA in free solution using electrophoresis with no sieving matrix. We successfully demonstrate the conjugation of polyamide drag-tags onto a set of four LDR primers designed to probe the K-ras oncogene for mutations highly associated with colorectal cancer, the simultaneous generation of fluorescently labeled LDR/drag-tag conjugate (LDR-dt) products in a multiplexed, single-tube format with mutant:WT ratios as low as 1:100, respectively, and the single-base, high-resolution separation of all four LDR-dt products. Separations were conducted in free solution with no polymer network using both a commercial capillary array electrophoresis (CAE) system and a PMMA microchip replicated via hot-embossing with only a Tris-based running buffer containing additives to suppress the EOF. Typical analysis times for LDR-dt were 11 min using the CAE system and as low as 85 s for the PMMA microchips. With resolution comparable to traditional gel-based CAE, FSCE along with microchip electrophoresis decreased the separation time by more than a factor of 40.

  20. Phase Behavior of the Ternary Solution Involving Rodlike and Random Coil Polymers

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The present paper covers the phase behavior of poly(p-benzamide)(PBA)/Nylon 6/H2SO4 and poly(p-phenylene terephthalamide) (PPTA)/Nylon 6/H2SO4 systems. The transition temperatures detected by the Depolarized Light Intensity measurements were used to construct the phase diagram in which the influence of temperature was shown. The enhanced depolarized light intensity observed in the ternary system suggests that the coil polymer chains may tend to be extended and contribute to the overall anisotropy of the liquid crystal phase.

  1. Solution-processable donor-acceptor polymers with modular electronic properties and very narrow bandgaps.

    Science.gov (United States)

    Foster, Michael E; Zhang, Benjamin A; Murtagh, Dustin; Liu, Yi; Sfeir, Matthew Y; Wong, Bryan M; Azoulay, Jason D

    2014-09-01

    Bridgehead imine-substituted cyclopentadithiophene structural units, in combination with highly electronegative acceptors that exhibit progressively delocalized π-systems, afford donor-acceptor (DA) conjugated polymers with broad absorption profiles that span technologically relevant wavelength (λ) ranges from 0.7 electronic properties so as to achieve very narrow optical bandgaps (Eg (opt) < 0.5 eV). This strategy affords modular DA copolymers with broad- and long-wavelength light absorption in the infrared and materials with some of the narrowest bandgaps reported to date.

  2. Polymer solution, fiber mat, and nanofiber membrane-electrode-assembly therewith, and method of fabricating same

    DEFF Research Database (Denmark)

    2016-01-01

    In one aspect of the present invention, a fiber mat is provided. The fiber mat includes at least one type of fibers, which includes one or more polymers. The fiber mat may be a single fiber mat which includes one type of fibers, or may be a dual or multi fiber mat which includes multiple types...... of fibers. The fibers may further include particles of a catalyst. The fiber mat may be used to form an electrode or a membrane. In a further aspect, a fuel cell membrane-electrode-assembly has an anode electrode, a cathode electrode, and a membrane disposed between the anode electrode and the cathode...

  3. Effect of Nano silica and Salts on Xanthan gum polymer-Bentonite solution

    OpenAIRE

    Fiveland, Annbjørg

    2015-01-01

    The application of nanotechnology shows positive results in the oil and gas industry, with respect to cement, drilling fluid and enhanced oil recovery. In this thesis, an optimized nano-fluid in Xanthan gum (XC) polymer treated bentonite mud system was investigated. The composition of the bestformulated nano-system is: 500g H2O+ 25g Bentonite+ 0.5g XC+ 2.5g KCl+ 0.1g Nano silica. The best-formulated mud system was further analysed for its viscoelastic behaviour. Simulatio...

  4. Adsorption properties of the nanozirconia/anionic polyacrylamide system-Effects of surfactant presence, solution pH and polymer carboxyl groups content

    Science.gov (United States)

    Wiśniewska, Małgorzata; Chibowski, Stanisław; Urban, Teresa

    2016-05-01

    The adsorption mechanism of anionic polyacrylamide (PAM) on the nanozirconia surface was examined. The effects of solution pH, carboxyl groups content in macromolecules and anionic surfactant (sodium dodecyl sulfate-SDS) addition were determined. The more probable structure of polymer adsorption layer was characterized based on the data obtained from spectrophotometry, viscosimetry and potentiometric titration methods. The adsorbed amount of polymer, size of macromolecules in the solution and surface charge density of ZrO2 particles in the absence and presence of PAM were assessed, respectively. Analysis of these results indicated that the increase of solution pH and content of carboxyl groups in the polymeric chains lead to more expanded conformations of adsorbing macromolecules. As a result, the adsorption of anionic polyacrylamide decreased. The SDS presence caused the significant increase of PAM adsorbed amount at pH 3, whereas at pH 6 and 9 the surfactant addition resulted in reduction of polymer adsorption level.

  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. Magnesium(II) polyporphine: The first electron-conducting polymer with directly linked unsubstituted porphyrin units obtained by electrooxidation at a very low potential

    Energy Technology Data Exchange (ETDEWEB)

    Vorotyntsev, Mikhail A., E-mail: mv@u-bourgogne.f [Institut de Chimie Moleculaire de l' Universite de Bourgogne, Universite de Bourgogne, CNRS UMR 5260, 21078 Dijon (France); Konev, Dmitry V. [Institut de Chimie Moleculaire de l' Universite de Bourgogne, Universite de Bourgogne, CNRS UMR 5260, 21078 Dijon (France); Devillers, Charles H., E-mail: charles.devillers@u-bourgogne.f [Institut de Chimie Moleculaire de l' Universite de Bourgogne, Universite de Bourgogne, CNRS UMR 5260, 21078 Dijon (France); Bezverkhyy, Igor; Heintz, Olivier [Institut Carnot de Bourgogne, Universite de Bourgogne, CNRS UMR 5209, 21078 Dijon (France)

    2010-09-01

    Electrooxidation of magnesium(II) porphine, a totally unsubstituted porphyrin, in acetonitrile solution under potentiostatic or potentiodynamic regime leads to a polymer film at the electrode surface. Polymer deposition takes place at extremely low potential, several hundred mV less positive even compared to the deposition potential for pyrrole or EDOT (at identical monomer concentrations) in the same solvent. Film thickness can be controlled by the passed deposition charge. This material and its THF-soluble fraction have been characterized by various electrochemical methods as well as by UV-visible and IR spectroscopies, XPS, XRD and MALDI-TOF techniques. This analysis has allowed us to conclude that the polymer film is composed by chains of Mg porphine building blocks, with single bonds between the neighboring units. In the course of the potential sweep, this polymer film demonstrates a redox response resembling that of polythiophene-coated electrodes. Namely, the film is electroactive and electronically conducting in two potential ranges (p- and n-doping), which are separated by a broad interval where the film possesses a much higher resistance. The polymer may be switched between all these redox states repeatedly by the change of the potential. The film capacitance in the electroactive potential intervals is proportional to the deposition charge.

  7. On the Link between Umbilic Geodesics and Soliton Solutions of Nonlinear PDEs

    OpenAIRE

    1995-01-01

    In this paper we describe a new class of soliton solutions, called umbilic solitons, for certain nonlinear integrable PDES. These umbilic solitons have the property that as the space variable x tends to infinity, the solution tends to a periodic wave, and as x tends to minus infinity, it tends to a phase shifted wave of the same shape. The equations admitting solutions in this new class include the Dym equation and equations in its hierarchy. The methods used to find and analyse these solutio...

  8. 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.

  9. SOLUTION RHEOLOGY OF HYPERBRANCHED POLYESTERS AND THEIR BLENDS WITH LINEAR POLYMERS

    Science.gov (United States)

    In this study, the rheological properties of different generations of hyperbranched polyesters in 1-methyl-2-pyrrolidinone solvent and their blends with poly(2-hydroxyethyl methacrylate) have ben investigated. All the hyperbranched polyester solutions exhibited Newtonian behavior...

  10. SOLUTION RHEOLOGY OF HYPERBRANCHED POLYESTERS AND THEIR BLENDS WITH LINEAR POLYMERS

    Science.gov (United States)

    In this study, the rheological properties of different generations of hyperbranched polyesters in 1-methyl-2-pyrrolidinone solvent and their blends with poly(2-hydroxyethyl methacrylate) have ben investigated. All the hyperbranched polyester solutions exhibited Newtonian behavior...

  11. Reduced Solubility of Polymer-Oriented Water for Sodium Salts, Sugars, Amino Acids, and other Solutes Normally Maintained at Low Levels in Living Cells,

    Science.gov (United States)

    1983-01-01

    polymer was prepared often with aid of gentle heating. The polymer solution was then inserted into 1/4 inch dialysis tubing, the ends of the sac tied...it was moved to another tube filled also with non-labelled solution and the process repeated many times until after the final washing, the sacs were...tragacanth (74C-0207); and gum xantham (888-0200); corn starch (6813-0216); potato starch (65B-2060); pectin (107B-0090); alginic acid (766-818); also

  12. 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.

  13. Removal of Chromium(VI) from Aqueous Solutions Using Fe₃O₄ Magnetic Polymer Microspheres Functionalized with Amino Groups.

    Science.gov (United States)

    Wang, Kai; Qiu, Guangming; Cao, Hongyu; Jin, Ruifa

    2015-12-03

    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.

  14. High fill factor polymer solar cells incorporating a low temperature solution processed WO{sub 3} hole extraction layer

    Energy Technology Data Exchange (ETDEWEB)

    Stubhan, Tobias; Li, Ning; Matt, Gebhard J. [Institute of Materials for Electronics and Energy Technology (I-MEET), Friedrich-Alexander-University Erlangen-Nuremberg, Martensstrasse 7, 91058 Erlangen (Germany); Luechinger, Norman A.; Halim, Samuel C. [Nanograde Llc., Wolfgang-Pauli-Strasse, P/O Box 239, 8093 Zurich (Switzerland); Brabec, Christoph J. [Institute of Materials for Electronics and Energy Technology (I-MEET), Friedrich-Alexander-University Erlangen-Nuremberg, Martensstrasse 7, 91058 Erlangen (Germany); Bavarian Center for Applied Energy Research (ZAE Bayern), Haberstrasse 2a, 91058 Erlangen (Germany)

    2012-12-15

    We demonstrate solution-processed tungsten trioxide (WO{sub 3}) incorporated as hole extraction layer (HEL) in polymer solar cells (PSCs) with active layers comprising either poly(3-hexylthiophene) (P3HT) or poly[(4,4'-bis(2-ethylhexyl)dithieno[3,2-b:2',3'-d]silole)-2,6-diyl-alt-(4,7-bis(2-thienyl)-2,1,3-benzothiadiazole)-5,50-diyl] (Si-PCPDTBT) mixed with a fullerene derivative. The WO{sub 3} layers are deposited from an alcohol-based, surfactant-free nanoparticle solution. A short, low-temperature (80 C) annealing is sufficient to result in fully functional films without the need for an oxygen-plasma treatment. This allows the application of the WO{sub 3} buffer layer in normal as well as inverted architecture solar cells. Normal architecture devices based on WO{sub 3} HELs show comparable performance to the PEDOT:PSS reference devices with slightly better fill factors and open circuit voltages. Very high shunt resistances (over 1 M{Omega} cm{sup 2}) and excellent diode rectification underline the charge selectivity of the solution-processed WO{sub 3} layers. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Linked open data on its way into next generation library management and discovery solutions

    Directory of Open Access Journals (Sweden)

    Axel Kaschte

    2013-01-01

    Full Text Available Library Linked Data Model is an important topic for librarianship and it is equally of interest to the many organizations that provide products and services to that community. Ex Libris, as one of those organizations, frequently gets asked: “Where do we see it fitting into our plans?”. In order to be able to answer questions like this, we need to ask: “What exactly are the problems being solved for the profession by this technology that can only be solved with the Library Linked Data model?” What most developers/providers of products analyzing the potential of library linked data would see is that at this stage, this technology is very much in the research stage. The presentation talks about the research ExLibris is involved in and how this can be utilized by innovative libraries to help defining the actual use cases in which the potential of the Library Linked Data Modell is indeed exploited.

  16. Biosorption Performance of Biodegradable Polymer Powders for the Removal of Gallium(III ions from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Lee Ching-Hwa

    2015-09-01

    Full Text Available Gallium (Ga is considered an important element in the semiconducting industry and as the lifespan of electronic products decrease annually Ga-containing effluent has been increasing. The present study investigated the use of biodegradable polymer powders, crab shell and chitosan, in the removal of Ga(III ions from aqueous solution. Ga(III biosorption was modeled to Lagergren-first, pseudo-second order and the Weber-Morris models. Equilibrium data was modeled to the Langmuir, Freundlich and Langmuir-Freundlich adsorption isotherms to determine the probable biosorption behavior of Ga(III with the biosorbents. The biosorbents were investigated by Fourier Transform Infrared Spectroscopy, X-ray Diffraction and Scanning Electron Microscopy/Energy Dispersive Spectra analysis.

  17. 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.

  18. Predicting the vapor-liquid equilibrium of hydrocarbon binary mixtures and polymer solutions using predetermined pure component parameters

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Sang Kyu [Division of Chemical Engineering and Molecular Thermodynamics Laboratory, Hanyang University, Seoul 133-791 (Korea, Republic of); Bae, Young Chan, E-mail: ycbae@hanyang.ac.kr [Division of Chemical Engineering and Molecular Thermodynamics Laboratory, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2012-05-25

    Highlights: Black-Right-Pointing-Pointer We have developed a close-packed lattice model for chain-like molecules. Black-Right-Pointing-Pointer The chain length dependence determined from Monte-Carlo simulation results were used. Black-Right-Pointing-Pointer To consider the volume effect, hole theory and two mixing steps were used. Black-Right-Pointing-Pointer A lattice fluid equation of state (LF-EoS) is presented for VLE of hydrocarbon mixtures. Black-Right-Pointing-Pointer Correlation of pure polymer solutions data with use of the LF-EoS. - Abstract: In our previous work, a new close-packed lattice model was developed for multi-component system of chain fluids with taking the chain length dependence from Monte-Carlo (MC) simulation results into account. In this work, we further extend this model to describe pressure, volume and temperature (PVT) properties, such as vapor-liquid equilibrium (VLE). To consider the effect of pressure on the phase behavior, the volume change effect is taken into account by introducing holes into the incompressible lattice model with two mixing steps. The corresponding new lattice fluid equation of state (LF-EoS) is applied to predict the thermodynamic properties of pure and binary mixtures of hydrocarbons as well as pure polymer solutions. The results of the proposed model are compared to other predictive approaches based on VLE calculations using predetermined pure model parameters without further adjustment. Thermodynamic properties predicted using the method developed in this work are consistent with the experimental data.

  19. Influence of polymeric electron injection layers on the electrical properties of solution-processed multilayered polymer light-emitting diodes

    Science.gov (United States)

    Itoh, Eiji; Kurami, Kazuhiko

    2016-02-01

    In this study, we fabricated multilayered polymer-based light-emitting diodes (pLEDs) with various solution-processed electron-injection layers (EILs), and investigated the influence of the EILs on the electrical properties of pLEDs in indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonic acid) (PEDOT:PSS)/poly[(9,9-dioctylfluorene-alt-(1,4-phenylene((4-sec-butylphenyl)amino)-1,4-phenylene))] (TFB) (HTL)/poly(9,9-dioctylfluorene-alt-1,4-benzothiadiazole) (F8BT) (EML)/EIL/Al structures. We have used the quaternized ammonium π-conjugated polyelectrolyte derivative (poly[(9,9-di(3,3‧-N,N‧-trimethylammonium)propylfluorenyl-2,7-diyl)-co-(1,4-phenylene)]diiodide salt) (PF-PDTA), a mixture of PF-PDTA and CS2CO3, and the aliphatic-amine-based polymer poly(ethylene imine) (PEI) as solution-processed EILs, and compared them with LiF as a solvent-free EIL. The EILs enhanced the electron injection and improve the pLED performance. High external quantum efficiencies of nearly 4% were obtained in the pLEDs with the combination of a multilayered structure fabricated by a transfer printing technique and EILs of a PF-PDTA:CS2CO3 mixture and PEI. On the other hand, the device with PF-PDTA exhibited lower efficiency, higher driving voltage, and larger leakage current at lower voltage. The migration of ionic charges was suggested from the abnormal dielectric behaviors, and serious damage on the electrode material occurred when both an acid hole-injection layer (PEDOT:PSS) and PF-PDTA were used. On the other hand, the pLEDs with ultrathin PEI showed high performance and stable device operation in terms of the influence of ionic charges.

  20. Polymers as Reference Partitioning Phase: Polymer Calibration for an Analytically Operational Approach To Quantify Multimedia Phase Partitioning.

    Science.gov (United States)

    Gilbert, Dorothea; Witt, Gesine; Smedes, Foppe; Mayer, Philipp

    2016-06-07

    Polymers are increasingly applied for the enrichment of hydrophobic organic chemicals (HOCs) from various types of samples and media in many analytical partitioning-based measuring techniques. We propose using polymers as a reference partitioning phase and introduce polymer-polymer partitioning as the basis for a deeper insight into partitioning differences of HOCs between polymers, calibrating analytical methods, and consistency checking of existing and calculation of new partition coefficients. Polymer-polymer partition coefficients were determined for polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and organochlorine pesticides (OCPs) by equilibrating 13 silicones, including polydimethylsiloxane (PDMS) and low-density polyethylene (LDPE) in methanol-water solutions. Methanol as cosolvent ensured that all polymers reached equilibrium while its effect on the polymers' properties did not significantly affect silicone-silicone partition coefficients. However, we noticed minor cosolvent effects on determined polymer-polymer partition coefficients. Polymer-polymer partition coefficients near unity confirmed identical absorption capacities of several PDMS materials, whereas larger deviations from unity were indicated within the group of silicones and between silicones and LDPE. Uncertainty in polymer volume due to imprecise coating thickness or the presence of fillers was identified as the source of error for partition coefficients. New polymer-based (LDPE-lipid, PDMS-air) and multimedia partition coefficients (lipid-water, air-water) were calculated by applying the new concept of a polymer as reference partitioning phase and by using polymer-polymer partition coefficients as conversion factors. The present study encourages the use of polymer-polymer partition coefficients, recognizing that polymers can serve as a linking third phase for a quantitative understanding of equilibrium partitioning of HOCs between any two phases.

  1. Magnetic molecularly imprinted polymers synthesized by surface-initiated reversible addition-fragmentation chain transfer polymerization for the enrichment and determination of synthetic estrogens in aqueous solution.

    Science.gov (United States)

    Chen, Fangfang; Zhang, Jingjing; Wang, Minjun; Kong, Jie

    2015-08-01

    Magnetic molecularly imprinted polymers have attracted significant interest because of their multifunctionality of selective recognition of target molecules and rapid magnetic response. In this contribution, magnetic molecularly imprinted polymers were synthesized via surface-initiated reversible addition addition-fragmentation chain transfer polymerization using diethylstilbestrol as the template for the enrichment of synthetic estrogens. The uniform imprinted surface layer and the magnetic property of the magnetic molecularly imprinted polymers favored a fast binding kinetics and rapid analysis of target molecules. The static and selective binding experiments demonstrated a desirable adsorption capacity and good selectivity of the magnetic molecularly imprinted polymers in comparison to magnetic non-molecularly imprinted polymers. Accordingly, a corresponding analytical method was developed in which magnetic molecularly imprinted polymers were employed as magnetic solid-phase extraction materials for the concentration and determination of four synthetic estrogens (diethylstilbestrol, hexestrol, dienestrol, and bisphenol A) in fish pond water. The recoveries of these synthetic estrogens in spiked fish pond water samples ranged from 61.2 to 99.1% with a relative standard deviation of lower than 6.3%. This study provides a versatile approach to prepare well-defined magnetic molecularly imprinted polymers sorbents for the analysis of synthetic estrogens in water solution. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Cross-linked branching nanohybrid polymer electrolyte with monodispersed TiO2 nanoparticles for high performance lithium-ion batteries

    Science.gov (United States)

    Ma, Cheng; Zhang, Jinfang; Xu, Mingquan; Xia, Qingbing; Liu, Jiatu; Zhao, Shuai; Chen, Libao; Pan, Anqiang; Ivey, Douglas G.; Wei, Weifeng

    2016-06-01

    Nanohybrid polymer electrolytes (NHPE) with ceramic particles have attracted significant attention owing to their improvement in electrochemical performance. However, particle aggregation and weak nanoparticle/polymer matrix interaction restrict their further application in lithium-ion batteries (LIBs). We demonstrate a facile in-situ polymerization/crystallization method to synthesize a homogeneous TiO2-grafted NHPE with a cross-linked branching structure, comprised of ion-conducting poly(ethylene glycol) methyl ether methacrylate (PEGMEM) and non-polar stearyl methacrylate (SMA). This technique is different from existing methods of blending functionalized ceramic particles into the polymer matrix. Highly monodispersed TiO2 nanocrystals enhance the effective interfacial interactions between particles and polymer matrix, which suppress the crystallization of ethylene oxide (EO) groups and facilitate forming continuously interconnected ion-conducting channels. Moreover, an increased dissociation degree of Li salt can also be achieved. The TiO2-grafted NHPE exhibits superior electrochemical properties with an ionic conductivity of 1.1 × 10-4 S cm-1 at 30 °C, a high lithium ion transference number and excellent interfacial compatibility with the lithium electrode. In particular, a lithium-ion battery based on TiO2-grafted NHPE demonstrates good C-rate performance, as well as excellent cycling stability with an initial discharge capacity of 153.5 mAh g-1 and a capacity retention of 96% after 300 cycles at 1 C (80 °C).

  3. One-Step Synthesis of Cross-Linked Ionic Polymer Thin Films in Vapor Phase and Its Application to an Oil/Water Separation Membrane.

    Science.gov (United States)

    Joo, Munkyu; Shin, Jihye; Kim, Jiyeon; You, Jae Bem; Yoo, Youngmin; Kwak, Moo Jin; Oh, Myung Seok; Im, Sung Gap

    2017-02-15

    In spite of the huge research interest, ionic polymers could not have been synthesized in the vapor phase because the monomers of ionic polymers contain nonvolatile ionic salts, preventing the monomers from vaporization. Here, we suggest a new, one-step synthetic pathway to form a series of cross-linked ionic polymers (CIPs) in the vapor phase via initiated chemical vapor deposition (iCVD). 2-(Dimethylamino)ethyl methacrylate (DMAEMA) and 4-vinylbenzyl chloride (VBC) monomers are introduced into the iCVD reactor in the vapor phase to form a copolymer film. Simultaneously in the course of the deposition process, the tertiary amine in DMAEMA and benzylic chloride in VBC undergo a Menshutkin nucleophilic substitution reaction to form an ionic ammonium-chloride complex, forming a highly cross-linked ionic copolymer film of p(DMAEMA-co-VBC). To the best of our knowledge, this is the first report on the synthesis of CIP films in the vapor phase. The newly developed CIP thin film is further applied to the surface modification of the membrane for oil/water separation. With the hydrophilic and underwater oleophobic membrane whose surface is modified with the CIP film, excellent separation efficiency (>99%) and unprecedentedly high permeation flux (average 2.32 × 10(5) L m(-2) h(-1)) are achieved.

  4. Removal of cobalt ions from aqueous solutions by polymer assisted ultrafiltration using experimental design approach. part 1: optimization of complexation conditions.

    Science.gov (United States)

    Cojocaru, Corneliu; Zakrzewska-Trznadel, Grazyna; Jaworska, Agnieszka

    2009-09-30

    The polymer assisted ultrafiltration process combines the selectivity of the chelating agent with the filtration ability of the membrane acting in synergy. Such hybrid process (complexation-ultrafiltration) is influenced by several factors and therefore the application of experimental design for process optimization using a reduced number of experiments is of great importance. The present work deals with the investigation and optimization of cobalt ions removal from aqueous solutions by polymer enhanced ultrafiltration using experimental design and response surface methodological approach. Polyethyleneimine has been used as chelating agent for cobalt complexation and the ultrafiltration experiments were carried out in dead-end operating mode using a flat-sheet membrane made from regenerated cellulose. The aim of this part of experiments was to find optimal conditions for cobalt complexation, i.e. the influence of initial concentration of cobalt in feed solution, polymer/metal ratio and pH of feed solution, on the rejection efficiency and binding capacity of the polymer. In this respect, the central compositional design has been used for planning the experiments and for construction of second-order response surface models applicable for predictions. The analysis of variance has been employed for statistical validation of regression models. The optimum conditions for maximum rejection efficiency of 96.65% has been figured out experimentally by gradient method and was found to be as follows: [Co(2+)](0)=65 mg/L, polymer/metal ratio=5.88 and pH 6.84.

  5. 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

    single heterojunction layer is based upon the idea of balancing good and bad properties within a single film. This proposal addresses the idea that the use of multiple layers that have differing electrical and optical functions could lead to greater efficiency because fewer materials compromises must be made. This idea is not new, multiple functional layer have been successfully used in cross-linked OLED's and organic small molecule evaporated PV devices. The main reason that multiple layers of polymers are not commonly deposited is that most conjugated polymers are mutually soluble in the same solvents. The work outlined in the proposal was intended to develop a new deposition strategy that would allow multiple organic layers to be deposited from solution using spin coating. The deposition method that we proposed was successful, sometimes, but ultimately not reliable. Instead we focused on more reliable methods to implement doping along the interface between layers. This work has been very successful. We found that using PEDOT:PSS, the PSS would form a surface layer of {approx}2-3 nm thickness that would mix with and electrochemically react with P3HT upon heating. This mechanism is also a crosslinking reaction in that H{sub 2} is released and permanent new bonds are formed. Using the Plextronics Inc. replacement to PEDOT:PSS, for which there are no mobile dopants, we were able to show that a second and different mechanism can be used to p-type dope organic materials. We are currently working with Plextronics to develop a new product. Finally we produced n-type doping of a thin fullerene layer near the cathode also using a self-assembly method. Low work function metals will diffuse into the BHJ layer and dope the fullerene upon heating. This doping also affects the vertical segregation of BHJ materials in a predictable way. We accomplished all of the scientific goals that we set out in the proposal written in May 2007. Some of the methods we proposed were not fully

  6. 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 t...

  7. 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.

    2005-01-01

    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 mater

  8. Quasi-logarithmic spacing law in dewetting patterns from the drying meniscus of a polymer solution

    CERN Document Server

    Chen, Yong-Jun; Mahara, Hitoshi; Yamaguchi, Tomohiko

    2012-01-01

    We report on a periodic precipitation pattern emerged from a drying meniscus via evaporation of a polystyrene solution in a Petri dish. It appeared a quasi-logarithmic spacing relation in the pattern as a result of stick-slip motion of the contact line towards the wall. A model based on the dynamics of the evaporating meniscus is proposed.

  9. Experimental investigations and numerical simulations for an open channel flow of a weak elastic polymer solution around a T-profile

    Energy Technology Data Exchange (ETDEWEB)

    Balan, C.; Neagoe, A.; Nistoran, D. [Hydraulics and Hydraulic Machinery Department - REOROM Group, University ' ' Politehnica' ' of Bucharest, Splaiul Independentei 313, 79590, Bucharest (Romania); Legat, V. [University of Louvain-la-Neuve - Center for Systems Engineering Applied Mechanics (CESAME), Batiment Euler, Av. Georges Lemaitre 4, 1348, Louvain-la-Neuve (Belgium)

    2004-03-01

    The present paper is concerned with experimental and numerical investigations of planar complex flows of ''weak'' elastic polymer solutions (whose concentration are below the critical overlap concentration), characterised by small relaxation times ({lambda}<0.1 s) and almost constant shear viscosities for small and medium shear rates. The main aim of the study is to detect to what extent a very small amount of elasticity present in a viscous fluid can influence its behaviour in complex flows, without introducing major modifications of classical rheological tests. The samples are polymer solutions of low PIB molecular weight dissolved in highly viscous Newtonian mineral oil. The analysed motion is steady, and takes place in an open channel around a ''T'' profile. Maximum values of the characteristic parameters for the experiments, the Reynolds and Weissenberg numbers, were 45 and 0.1, respectively. The experiments show a decrease of the wake length downstream the profile for weak elastic solutions in comparison to the Newtonian solvent. Actually, the same wake length as in the Newtonian case was obtained for tested polymer solutions, but at higher Re numbers. Numerical simulations using the Giesekus model predict the same behaviour and are consistent with experiments from both qualitative and quantitative point of views. The results of research conclude that, even in small amounts, the presence of elasticity in pure viscous liquids induces quantitative changes from Newtonian flow in complex dominant elongational flows, at elongational rates for which the sudden thickening of extensional viscosity is remarkable. The study is important, since it should enable better understanding and modelling of viscoelastic flows that involve dilute polymer solutions, or fluids with similar rheology; biofluid mechanics being one area of application of this research. Corroboration of experimental flow visualization with numerical simulation is

  10. 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.

  11. Evaluation of polymer inclusion membranes containing crown ethers for selective cesium separation from nuclear waste solution.

    Science.gov (United States)

    Mohapatra, P K; Lakshmi, D S; Bhattacharyya, A; Manchanda, V K

    2009-09-30

    Transport behaviour of (137)Cs from nitric acid feed was investigated using cellulose triacetate plasticized polymer inclusion membrane (PIM) containing several crown ether carriers viz. di-benzo-18-crown-6 (DB18C6), di-benzo-21-crown-7 (DB21C7) and di-tert-butylbenzo-18-crown-6 (DTBB18C6). The PIM was prepared from cellulose triacetate (CTA) with various crown ethers and plasticizers. DTBB18C6 and tri-n-butyl phosphate (TBP) were found to give higher transport rate for (137)Cs as compared to other carriers and plasticizers. Effect of crown ether concentration, nitric acid concentration, plasticizer and CTA concentration on the transport rate of Cs was also studied. The Cs selectivity with respect to various fission products obtained from an irradiated natural uranium target was found to be heavily dependent on the nature of the plasticizer. The present work shows that by choosing a proper plasticizer, one can get either good transport efficiency or selectivity. Though TBP plasticized membranes showed good transport efficiency, it displayed poor selectivities. On the other hand, an entirely opposite separation behaviour was observed with 2-nitrophenyloctylether (NPOE) plasticized membranes suggesting the possible application of the later membranes for the removal of bulk (137)Cs from the nuclear waste. The stability of the membrane was tested by carrying out transport runs for nearly 25 days.

  12. Calculation of the (liquid + liquid) equilibrium of solutions of hyperbranched polymers with the lattice-cluster theory combined with an association model

    Energy Technology Data Exchange (ETDEWEB)

    Zeiner, T. [Technical University of Dortmund, Lehrstuhl fuer Fluidverfahrenstechnik, Emil-Figge Str. 70, 44227 Dortmund (Germany); Browarzik, C. [Technical University of Berlin, Institut fuer Prozess- und Verfahrenstechnik (TK7), Fachgebiet Thermodynamik und thermische Verfahrenstechnik, Strasse des 17, Juni 135, 10623 Berlin (Germany); Browarzik, D., E-mail: dieter.browarzik@chemie.uni-halle.de [Martin-Luther University Halle-Wittenberg, Institut fuer Chemie/Physikalische Chemie, 06099 Halle (Germany); Enders, S. [Technical University of Berlin, Institut fuer Prozess- und Verfahrenstechnik (TK7), Fachgebiet Thermodynamik und thermische Verfahrenstechnik, Strasse des 17, Juni 135, 10623 Berlin (Germany)

    2011-12-15

    Highlights: > The (liquid + liquid) equilibrium of hyperbranched polyester solutions is calculated. > The solvents are n-alkanes, propan-1-ol, and butan-1-ol. > The lattice-cluster theory is combined with a chemical association model. > The solvent molecules are assumed to be linear chains of segments. > The calculations agree reasonably well with the experimental data. - Abstract: The (liquid + liquid) equilibrium of solutions of hyperbranched polyesters is calculated with the lattice-cluster theory (LCT) combined with a chemical association model. The considered solvents are n-alkanes as well as propan-1-ol and butan-1-ol. The structure of the solvents is also considered in the framework of the LCT, assuming the solvent molecules as linear chains of several segments. For polymer solutions with the non-associating n-alkanes only the self association of the hyperbranched polymer molecules has to be considered by the chemical association lattice model (CALM). For the solutions of the type alcohol + hyperbranched polymer additionally the cross association is taken into account by a modified version of the extended chemical association lattice model (ECALM). The association effects are proved to influence strongly the phase equilibrium. Calculating the cloud-point curve and the critical point the polydispersity of the polymer samples is neglected. There is a reasonable agreement of the calculated curves with the experimental data taken from the literature.

  13. Phase separation of polymer solutions. The calculation of the cloudpoint curve with a concentration and temperature-dependent free energy correction parameter

    NARCIS (Netherlands)

    Emmerik, van P.T.; Smolders, C.A.

    1973-01-01

    The free enthalpy correction parameter g in the Flory-Huggins equation for the Gibbs free enthalpy of mixing in polymer solutions is considered generally as a concentration- and temperature-independent parameter. It has been extended here with linear concentration- and temperature-dependent terms. W

  14. Phase separation in polymer solutions. II. Determination of thermodynamic parameters of poly (2,6-dimethyl-1,4-phenylene oxide) toluene mixtures

    NARCIS (Netherlands)

    Emmerik, van 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

  15. 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.

  16. Solution-processable graphene oxide as an efficient hole transport layer in polymer solar cells.

    Science.gov (United States)

    Li, Shao-Sian; Tu, Kun-Hua; Lin, Chih-Cheng; Chen, Chun-Wei; Chhowalla, Manish

    2010-06-22

    The utilization of graphene oxide (GO) thin films as the hole transport and electron blocking layer in organic photovoltaics (OPVs) is demonstrated. The incorporation of GO deposited from neutral solutions between the photoactive poly(3-hexylthiophene) (P3HT):phenyl-C61-butyric acid methyl ester (PCBM) layer and the transparent and conducting indium tin oxide (ITO) leads to a decrease in recombination of electrons and holes and leakage currents. This results in a dramatic increase in the OPV efficiencies to values that are comparable to devices fabricated with PEDOT:PSS as the hole transport layer. Our results indicate that GO could be a simple solution-processable alternative to PEDOT:PSS as the effective hole transport and electron blocking layer in OPV and light-emitting diode devices.

  17. Removal of transition metals from dilute aqueous solution by carboxylic acid group containing absorbent polymers

    Science.gov (United States)

    A new carboxylic acid group containing resin with cation exchange capacity, 12.67 meq/g has been used to remove Cu2+, Co2+ and Ni2+ ions from dilute aqueous solution. The resin has Cu2+, Co2+ and Ni2+ removal capacity, 216 mg/g, 154 mg/g and 180 mg/g, respectively. The selectivity of the resin to ...

  18. A hybrid CMOS-imager with a solution-processable polymer as photoactive layer

    Science.gov (United States)

    Baierl, Daniela; Pancheri, Lucio; Schmidt, Morten; Stoppa, David; Dalla Betta, Gian-Franco; Scarpa, Giuseppe; Lugli, Paolo

    2012-11-01

    The solution-processability of organic photodetectors allows a straightforward combination with other materials, including inorganic ones, without increasing cost and process complexity significantly compared with conventional crystalline semiconductors. Although the optoelectronic performance of these organic devices does not outmatch their inorganic counterparts, there are certain applications exploiting the benefit of the solution-processability. Here we demonstrate that the small pixel fill factor of present complementary metal oxide semiconductor-imagers, decreasing the light sensitivity, can be increased up to 100% by replacing silicon photodiodes with an organic photoactive layer deposited with a simple low-cost spray-coating process. By performing a full optoelectronic characterization on this first solution-processable hybrid complementary metal oxide semiconductor-imager, including the first reported observation of different noise types in organic photodiodes, we demonstrate the suitability of this novel device for imaging. Furthermore, by integrating monolithically different organic materials to the chip, we show the cost-effective portability of the hybrid concept to different wavelength regions.

  19. Enhanced efficiency of inverted polymer solar cells by using solution-processed TiOx/CsOx cathode buffer layer.

    Science.gov (United States)

    Zhou, Xiaodong; Fan, Xi; Sun, Xianke; Zhang, Yunli; Zhu, Ziqiang

    2015-01-01

    In this work, a double-buffer film of TiOx coated with CsOx (TiOx/CsOx) was solution prepared to be applied in poly(3-hexylthiophene):indene-C60 bisadduct (P3HT:ICBA) and P3HT:[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) inverted polymer solar cells (PSCs). Compared with TiOx films and CsOx films, the TiOx/CsOx double-buffer film exhibited a favorable energy-level alignment among TiOx, CsOx, and the electron acceptor of PCBM or ICBA a better surface morphology; and an enhanced wetting and adhesion property with a contact angle of 21.0°, leading to a higher electron mobility of 5.52 × 10(-3) cm(2) V(-1)·s(-1). Moreover, the P3HT:ICBA and P3HT:PCBM photovoltaic devices with the double-buffer film showed the best power conversion efficiency up to 5.65% and 3.76%, respectively. Our results not only present that the double-buffer film is superior than the single film of TiOx and CsOx, but also imply that the solution-processed film has a potential to be generally used in roll-to-roll processed organic photovoltaic devices.

  20. 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.