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In this study, an investigation has been carried out regarding the reciprocating translocation (i.e. back and forth motion) of a polymer chain in a microchannel. External force is one of the important factors in the movement of the polymer chain. In this investigation, variable forces are applied to the polymer chain and all fluid particles in which at a certain time, the direction of the force and the movement will change in this simulation. The behaviour and the properties of the chain, such as the radius of gyration, the centre of mass velocity and the amount of translocation, have been examined in this reciprocating movement. Based on the present results, when employing a longer polymer chain and especially applying the force on the polymer and fluid particles, due to the inertia effect, it would not be easily possible to stop the polymer chain. Consequently, changing the direction of polymer motion would not instantly occur by changing the force direction. In fact, some amount of displacement and lost time (LT) (around 6 dissipative particle dynamics units out of a total time of 40) will be associated with the case of applying force on just a polymer chain and imposing variable external force on all particles, LT has increased dramatically (dimensionless LT parameter is around 50%). The present method is a suitable tool for simulating the variable movement of polymer for the design of micro-actuators or polymer sensors. [ABSTRACT FROM AUTHOR]

An electroelastic constitutive model for dielectric elastomers based on the Langevin statistic is proposed in this paper. We start by deriving the Gibbs energy for electroelastic processes to obtain the Langevin function representing statistical configuration of polymer chain segments. To make a closed-form solution possible, we use the average stretch given by the 8-chain model to express the proposed model for the evaluation of its instability characteristics. We find that our proposed model can capture well the experimental data from the homogeneous responses and the instability characteristics. [ABSTRACT FROM AUTHOR]

The adsorption behavior of polymer chains on a checkerboard‐patterned surface consisting of attractive and neutral square blocks is simulated using dynamic Monte Carlo method. The polymer chain is adsorbed on the surface below the critical adsorption temperature Tc and finally form a recognizable state below the pattern recognition temperature Tr. Both Tc and Tr increase with increasing the block width L. The increase of Tc is because that the effect of neutral blocks reduces with increasing L, while the increase of Tr indicates that it is easy for the adsorbed polymer chain to recognize large pattern. Moreover, below Tc, the polymer chain is in a multi‐block adsorption state (MBAS) and multi‐block recognition state (MBRS) for small L and in a single‐block adsorption state (SBAS) and single‐block recognition state (SBRS) for large L. For moderate L, as the temperature decreases, the polymer changes from the SBAS to the MBAS or from SBRS to MBRS below the single‐block to multi‐block adsorption temperature Tsm. Tc and Tsm increase with increasing N, whereas Tr decreases with increasing N. Lastly, the intra‐polymer attraction helps the polymer chain to recognize in a SBRS. [ABSTRACT FROM AUTHOR]

A statistically based strain energy is proposed for rubber-like materials at large stretches. It is based on the micro-mechanically vectorial modeling of a single polymer chain, and its entropy is used in order to account for the entropic elasticity of rubbery macromolecules. We propose a framework for derivation of a microscopic free energy function based on a multidimensional form of a generic normal (Gauss) probability distribution function (pdf). Homogenization of the microscopic free energy by means of statistical tools renders a macroscopic free energy. The random variables of the general formulation are specified as bond angle differences, representing bending and torsion, respectively, for each bead of the single chain. A further step is a formulation of both quantities in terms of the applied stretch, which eventually renders the macroscopic strain energy as a hyperelastic energy function. Additionally, we propose a methodology to satisfy a normalization condition for the related integral of the pdf over the constraint statistic domain. A numerical example illustrates the capability of the proposed energy function to simulate the S-shape behavior of the well-known experimental data for vulcanized rubbers by Treloar (Trans Faraday Soc 40:59–70, 1944). [ABSTRACT FROM AUTHOR]

The influences of interactions between carboxymethyl cellulose (CMC) and CMC/europium (III)–terbium (III) (CET) on the structure and properties of the resultant CMC/CET films were investigated by rheology at three stages of the film-drying process. According to the water content at different drying times, the kinetics curves during the film-drying process were drawn. Then, the rheology properties of film-forming solutions during the drying process were characterized by dynamic modulus, Han plots, zero shear complex viscosity and relaxation time. When the water content was 90%, the film contained either 0.1 or 0.2 g of CET, which had good fluidity, while the film with 0.3 g of CET was elastic-dominated. Han plots and XRD analyses showed that the interactions between the CMC and CET were not hydrogen bonds but random entanglements. The zero-shear complex viscosity and relaxation time spectrum confirmed that the entanglements enhanced as the CET content increased. Meanwhile, aggregation formed in the solution of CMC with 0.3 g of CET. When CMC-CET films with different CET additions were compared, the film with 0.2 g of CET had an even and tight sheet structure, the greatest fluorescence intensity, and superior tensile strength of 78.76 MPa. [ABSTRACT FROM AUTHOR]

Under electric loading produced by compliant electrodes, a dielectric elastomer is prone to material instabilities which, in a microstructural level, may connect to single polymer chain instability. To reveal if such connection exists, we aim to use an electroelastic energy model for single polymer chain to study the chain instability. We approximate curvature shape of the chain under the electric loading by using trigonometry series in a spatial coordinate. The Rayleigh–Ritz method is then applied to solve the energy equation formed by the trigonometry series. We demonstrate in the numerical examples that the instability of the chain may occur at the value of electric field with corresponding configuration of the chain close to its full length. • An electroelastics energy equation for studying instability of a polymer chain. • The Rayleigh-Ritz method used to evaluate single polymer chain equilibrium. • Energy from chain dipole moments evaluated with the von Mises–Fisher distribution. • The onset of chain instability indicated by its straight configuration. [ABSTRACT FROM AUTHOR]

In recent years, the synthesis of monomer sequence-defined polymers has expanded into broad-spectrum applications in biomedical, chemical, and materials science fields. Pursuing the characterization and inverse design of these polymer systems requires our fundamental understanding not only at the individual monomer level, but also considering the chain scales, such as polymer configuration, self-assembly, and phase separation. However, our accessibility to this field is still rudimentary due to the limitations of traditional design approaches, the complexity of chemical space along with the burdened cost and time issues that prevent us from unveiling the underlying monomer sequence-structure-property relationships. Fortunately, thanks to the recent advancements in molecular dynamics simulations and machine learning (ML) algorithms, the bottlenecks in the tasks of establishing the structure-function correlation of the polymer chains can be overcome. In this review, we will discuss the applications of the integration between ML techniques and coarse-grained molecular dynamics (CGMD) simulations to solve the current issues in polymer science at the chain level. In particular, we focus on the case studies in three important topics—polymeric configuration characterization, feed-forward property prediction, and inverse design—in which CGMD simulations are leveraged to generate training datasets to develop ML-based surrogate models for specific polymer systems and designs. By doing so, this computational hybridization allows us to well establish the monomer sequence-functional behavior relationship of the polymers as well as guide us toward the best polymer chain candidates for the inverse design in undiscovered chemical space with reasonable computational cost and time. Even though there are still limitations and challenges ahead in this field, we finally conclude that this CGMD/ML integration is very promising, not only in the attempt of bridging the monomeric and macroscopic characterizations of polymer materials, but also enabling further tailored designs for sequence-specific polymers with superior properties in many practical applications.

The quantitative characterization of micromechanical properties of polymer biomaterials and the development of advanced biological micro / nano-technology and devices need quantitative analysis of the statistical thermodynamic properties and behaviors of polymer chains such as biological macromolecules in complex microenvironment. To achieve this goal, the cross research of continuum mechanics and statistical thermodynamics plays a very important role. Aimed at the mechanics problems in this field, starting from the force stretching of DNA molecules, several theoretical models were introduced to describe the statistical thermodynamic properties of polymer chains, and the wormlike chain model was deemed to have more significant advantages in describing the relationship between forces and configuration changes of semiflexible polymer chains than other ideal random chain models, so that the qualitative and quantitative understanding of the statistical thermodynamic properties and behaviors of polymers in complex microenvironment was deemed to be largely dependent on the relevant research progresses based on the wormlike chain model. Based on this fact, the research on the influence of geometric constraints on the random conformation distribution of polymer chains, the research on the statistical thermodynamic model for polymer chains under the simultaneous action of tension and constraints, and the simulation research on the statistical physical properties of polymer chains based on high-performance computers, were reviewed, and the latest progress and challenging problems in the research of statistical thermodynamic properties and behavior of worm chains under different constraints and stress microenvironments were summarized. Finally, through summary and analysis, it is pointed out that the study of statistical thermodynamics of worm chains in complex microenvironment is an important basis for understanding life phenomena from the molecular and cellular scale, developing advanced micro- and nano-technology and constructing the constitutive relationship of soft matter. At present, it has become a very challenging frontier topic in the interdisciplinary of mechanics. [ABSTRACT FROM AUTHOR]

The influences of interactions between carboxymethyl cellulose (CMC) and CMC/europium (III)–terbium (III) (CET) on the structure and properties of the resultant CMC/CET films were investigated by rheology at three stages of the film-drying process. According to the water content at different drying times, the kinetics curves during the film-drying process were drawn. Then, the rheology properties of film-forming solutions during the drying process were characterized by dynamic modulus, Han plots, zero shear complex viscosity and relaxation time. When the water content was 90%, the film contained either 0.1 or 0.2 g of CET, which had good fluidity, while the film with 0.3 g of CET was elastic-dominated. Han plots and XRD analyses showed that the interactions between the CMC and CET were not hydrogen bonds but random entanglements. The zero-shear complex viscosity and relaxation time spectrum confirmed that the entanglements enhanced as the CET content increased. Meanwhile, aggregation formed in the solution of CMC with 0.3 g of CET. When CMC-CET films with different CET additions were compared, the film with 0.2 g of CET had an even and tight sheet structure, the greatest fluorescence intensity, and superior tensile strength of 78.76 MPa.

Monte Carlo simulations are used to simulate a single polymer chain in a more generalized model. The more generalized model differs from the simpler models by including dipole-dipole interactions. The polymer chain is modeled as a freely rotating chain where the neighboring beads are connected by harmonic spring. Excluded volume effects are included employing modified Lennard-Jones potential. As the extension in this work, each monomer unit carries permanently a freely-rotating electric dipole moment. After getting the system equilibrated the average values are measured and Θ-temperature of the system is determined. The effects of the presence of the dipole moments to the Θ-temperature of the system are investigated. The results are analyzed in comparison with a bare model. [ABSTRACT FROM AUTHOR]

In this research, the numerical simulation of a soft polymer micro actuator performance has been investigated using the dissipative particle dynamics method in electro-osmotic flow. Effective factors including electro-osmotic flow and polymer chain parameters have been studied. First of all, considering a wide range of electro-osmotic parameters, the validation of analytical results is carried out in a simple micro channel. The electric field and zeta potential changes are linearly related to the flow rate, and the kh parameter behaves nonlinearly to around the kh = 10. In the following, a convergent–divergent channel is used for the soft micro actuator simulation in which a polymer chain as a heart of actuation is embedded in the middle. As the main control parameter, the direction of the electric field is changed every 4 s, and it leads to a reciprocating motion. The numerical results indicate that the displacement of the soft polymer chain will be increased by enhancing the electric field, the number of beads, decreasing the harmonic bond coefficient and also exposing more length of a polymer chain in front of fluid flow. The results of this study may be useful for some future applications such as artificial fibres and muscles. [ABSTRACT FROM AUTHOR]

Organic materials have been found to be promising candidates for low-temperature thermoelectric applications. In particular, poly (3-hexylthiophene) (P3HT) has been attracting great interest due to its desirable intrinsic properties, such as excellent solution processability, chemical and thermal stability, and high field-effect mobility. However, its poor electrical conductivity has limited its application as a thermoelectric material. It is therefore important to improve the electrical conductivity of P3HT layers. In this work, we studied how molecular weight (MW) influences the thermoelectric properties of P3HT films. The films were doped with lithium bis(trifluoromethane sulfonyl) imide salt (LiTFSI) and 4-tert butylpyridine (TBP). Various P3HT layers with different MWs ranging from 21 to 94 kDa were investigated. UV−Vis spectroscopy and atomic force microscopy (AFM) analysis were performed to investigate the morphology and structure features of thin films with different MWs. The electrical conductivity initially increased when the MW increased and then decreased at the highest MW, whereas the Seebeck coefficient had a trend of reducing as the MW grew. The maximum thermoelectric power factor (1.87 μW/mK2) was obtained for MW of 77 kDa at 333 K. At this temperature, the electrical conductivity and Seebeck coefficient of this MW were 65.5 S/m and 169 μV/K, respectively.

Abstract Polymers are widely used in industry and in our daily life because of their diverse functionality, light weight, low cost and excellent chemical stability. However, on some applications such as heat exchangers and electronic packaging, the low thermal conductivity of polymers is one of the major technological barriers. Enhancing the thermal conductivity of polymers is important for these applications and has become a very active research topic over the past two decades. In this review article, we aim to: 1). systematically summarize the molecular level understanding on the thermal transport mechanisms in polymers in terms of polymer morphology, chain structure and inter-chain coupling; 2). highlight the rationales in the recent efforts in enhancing the thermal conductivity of nanostructured polymers and polymer nanocomposites. Finally, we outline the main advances, challenges and outlooks for highly thermal-conductive polymer and polymer nanocomposites. [ABSTRACT FROM AUTHOR]

Fluoride complexes of indium(III) with mixed monovalent M+ (M = Rb, Cs, NH4) and divalent [Cu(H2O)4]2+ cations of the composition M[Cu(H2O)4]InF6·nH2O (M = Rb, Cs, NH4; n = 0, 1) are synthesized for the first time and their crystal structures with a polymer chain character are studied. The structures of M[Cu(H2O)4]InF6·nH2O (M = Rb, Cs, NH4; n = 0, 1) are formed of monovalent Rb+, Cs+, NH4+ cations respectively, complex [Cu(H2O)4]2+ cations, slightly distorted octahedral complex [InF6]3- anions, and crystallization H2O molecules. By attaching one F atom from the neighboring InF6 groups, the [Cu(H2O)4]2+ cations form distorted octahedral Cu(H2O)4F2 groups. Via the bridging F atoms, the [Cu(H2O)4]2+ cations and [InF6]3- anions alternatively join into zigzag anionic polymer chains. A branched system of hydrogen O-H···F, O-H···Ow, and N-H···F bonds arrange the anionic chains into a threedimensional framework in whose voids the monovalent cations and crystallization H2O molecules are located. The structures of M[Cu(H2O)4]InF6·nH2O (M = Rb, Cs, NH4; n = 0, 1) are a new structure type. [ABSTRACT FROM AUTHOR]

We investigated the self-oscillating behaviors of two types of polymer chains induced by the Belousov–Zhabotinsky (BZ) reaction. One consisted of N-isopropylacrylamide (NIPAAm) and the Ru catalyst of the BZ reaction, and the other consisted of NIPAAm, the Ru catalyst, and acrylamide-2-methylpropanesulfonic acid (AMPS) with a negatively charged domain as a solubility control site. A comparison of the two types of self-oscillation systems showed that the anionic AMPS portion of the polymer chain significantly affected the self-oscillating behavior under strongly acidic condition. The periods of self-oscillation for the two types of self-oscillating polymer chains were investigated by changing the initial concentrations of the three BZ substrates and the temperature. As a result, it was demonstrated that the period of self-oscillation could be controlled by the concentration of the BZ substrates and the temperature. Furthermore, the activation energies of the two types of the self-oscillating polymer chains gave similar values as normal BZ reactions, i.e., not including the self-oscillating polymer system with a Ru moiety. In addition, it was clarified the activation energy was hardly affected by the initial concentration of the three BZ substrates.

The statistical mechanics and the thermodynamics of small systems are characterized by the non-equivalence of the statistical ensembles. When concerning a polymer chain or an arbitrary chain of independent units, this concept leads to different force-extension responses for the isotensional (Gibbs) and the isometric (Helmholtz) thermodynamic ensembles for a limited number of units (far from the thermodynamic limit). While the average force-extension response has been largely investigated in both Gibbs and Helmholtz ensembles, the full statistical characterization of this thermo-mechanical behavior has not been approached by evaluating the corresponding probability densities. Therefore, we elaborate in this paper a technique for obtaining the probability density of the extension when force is applied (Gibbs ensemble) and the probability density of the force when the extension is prescribed (Helmholtz ensemble). This methodology, here developed at thermodynamic equilibrium, is applied to a specific chain composed of units characterized by a bistable potential energy, which is able to mimic the folding and unfolding of several macromolecules of biological origin.

The title compound, C19H20N4O3S, was synthesized by refluxing equimolar amounts of 1-phenyl-3-methyl-4-propionylpyrazol-5-one and benzenesulfonyl hydrazide in ethanol. The compound crystallizes in the keto form and the carbonyl O atom forms an intramolecular N—H...O hydrogen bond with the neighbouring NH group. There is also C—H...O short contact involving the neighbouring phenyl ring. Probably as a result of this, the phenyl ring is inclined to the pyrazolone ring by only 7.58 (12)°. The dihedral angle between the phenyl ring and the benzenesulfonyl ring is 22.78 (11)°. In the crystal, molecules are linked by pairs of N—H...O hydrogen bonds, forming inversion dimers with an R22(14) ring motif. The dimers are linked via pairs of C—H...O hydrogen bonds, forming chains propagating along [100].

We demonstrate that the arrangement differs of posts have significant effect on the translocation of polymer chains which are embedded in the post arrays by using Monte Carlo algorithm. Due to the equivalent entropic force, polymers have a tendency to translocate to the disordered-arranged post array side other than the ordered-arranged side even though the post densities are equal on both sides. By changing the diameter of the posts, we find that the associated translocation times are strongly affected by the structure of the post array. Since the entropic force is almost identical for each monomer of the polymer chain and the free energy difference between two differently-arranged sides increases linearly with the polymer chain length, the directional preference strongly depends on the polymer chain length, and the ratio between the probabilities for a polymer to move either side obeys the Boltzmann distribution. Hence, a new microfabricated device which is used to separate deoxyribonucleic acid (DNA) by molecular weight can be designed using this idea. Moreover, this study can help us to develop a better understanding on the passages of polymers across membranes in nature. [ABSTRACT FROM AUTHOR]

The crystal structures of isostructural mixed-ligand fluorosulfate complex compounds of indium(III) M[InF(SO)HO] (M = K, NH), formed of K cations, NH respectively, and complex [InF(SO)HO] anions are determined. In the complex anion, the indium atom surrounded by three F atoms, the oxygen atom of the coordinated HO molecule, and two oxygen atoms of the bridging sulfate group forms a slightly distorted octahedron (CN 6). Via alternating bridging SO groups, the polyhedra of In(III) atoms are arranged in polymer chains. The O-H•••F hydrogen bonds organize the chains in a three-dimensional network. The K and NH cations are located in the structure framework and additionally strengthen it. [ABSTRACT FROM AUTHOR]

Isostructural fluorooxalate complex compounds of indium(III) M[InF(CO)HO] (M = K, Rb), being the first representatives of a new class of mixed-ligand fluoro-containing complex compounds of indium(III) are synthesized and structurally studied for the first time. The crystal structures of M[InF(CO)HO] (M = K, Rb) are formed of K cations (Rb respectively) and complex [InF(CO)HO] anions. The indium atom in the complex anion is surrounded by four F atoms, two of which are bridging, the oxygen atom of the coordinated HO molecule, and two oxygen atoms of the bis-bidentate (tetradentate) oxalate group. The coordination polyhedron of the indium atom (CN 7) is a pentagonal bipyramid. Via alternating double bridging F atoms and tetradentate bridging CO group, the In(III) atom polyhedra are arranged in polymers chains. Via hydrogen O-H⋯F bonds the chains are organized in layers. Between the layers, the K or Rb cations are located, which strengthen the crystal structure. [ABSTRACT FROM AUTHOR]

This review introduces the self-oscillating behavior of two types of nonthermoresponsive polymer systems with Ru catalyst moieties for the Belousov-Zhabotinsky (BZ) reaction: one with a poly-vinylpyrrolidone (PVP) main chain, and the other with a poly(2-propenamide) (polyacrylamide) (PAM) main chain. The amplitude of the VP-based self-oscillating polymer chain and the activation energy for self-oscillation are hardly affected by the initial concentrations of the BZ substrates. The influences of the initial concentrations of the BZ substrates and the temperature on the period of the swelling-deswelling self-oscillation are examined in detail. Logarithmic plots of the period against the initial concentration of one BZ substrate, when the concentrations of the other two BZ substrates are fixed, show good linear relationships. The period of the swelling-deswelling self-oscillation decreases with increasing temperature, in accordance with the Arrhenius equation. The maximum frequency (0.5 Hz) of the poly(VP-co-Ru(bpy)3) gel is 20 times that of the poly(NIPAAm-co-Ru(bpy)3) gel. It is also demonstrated that the amplitude of the volume self-oscillation for the gel has a tradeoff with the self-oscillation period. In addition, this review reports the self-oscillating behavior of an AM-based self-oscillating polymer chain as compared to that of the VP-based polymer chain.

In this paper, we investigated the activation energies of the aggregation–disaggregation self-oscillation induced by the Belousov-Zhabotinsky (BZ) reaction by utilizing the nonthermoresponsive polymer chain in a wide temperature range. This is because the conventional type self-oscillating polymer chain, with thermoresponsive poly(Nisopropylacrylamide) (poly(NIPAAm) main-chain covalently bonded to the ruthenium catalyst (Ru(bpy)3) of the BZ reaction, cannot evaluate the activation energy over the lower critical solution temperature (LCST). The nonthermoresponsive self-oscillating polymer chain is composed of a poly-vinylpyrrolidone (PVP) main-chain with the ruthenium catalyst (Ru(bpy)3). As a result, we clarified that the activation energy of the aggregation–disaggregation self-oscillation of the polymer chain is hardly affected by the concentrations of the BZ substrates. In addition, the activation energy of the nonthermoresponsive self-oscillating polymer chain was found to be almost the same value as normal BZ reaction, i.e., not including the self-oscillating polymer system with Ru moiety.

We succeeded in causing transmittance self-oscillations of a novel self-oscillating polymer chain induced by the Belouzov-Zhabotinsky (BZ) reaction under constant conditions. The novel polymer chain was composed of a biocompatible and non-thermoresponsive poly-vinylpyrrolidone (PVP) main-chain, covalently-bonded to the ruthenium catalyst (Ru(bpy)3) of the BZ reaction. We investigated the influence of initial substrate concentrations of the three BZ substrates on the transmittance self-oscillation of the novel polymer solution. As a result, we demonstrated that the width of the transmittance self-oscillation is significantly affected by these initial concentrations. However, the amplitude of the transmittance self-oscillation is hardly affected by the BZ substrate conditions. Furthermore, the period of the self‑oscillation has a good linear relationship to the concentration of the BZ substrates. Therefore, the period of the self-oscillation can be controlled by the selection of the initial concentrations of the BZ substrates.

If we could realize an autonomous polymer system driven under biological conditions by a tailor-made molecular design, human beings could create unprecedented biomimetic functions and materials such as heartbeats, autonomous peristaltic pumps, etc. In order to achieve this objective, we have investigated the molecular design of such a polymer system. As a result, we were the first to demonstrate a self-oscillating polymer system driven in a solution where only malonic acid existed, which could convert the chemical energy of the Belousov-Zhabotinsky (BZ) reaction into a change in the conformation of the polymer chain. To cause the self-oscillation in solution, we have attempted to construct a built-in system where the required BZ system substrates other than the organic acid are incorporated into the polymer itself. That is, the novel polymer chain incorporated the metal catalyst of the BZ reaction, a pH-control site and an oxidant supply site at the same time. As a result of introducing the pH control and oxidant supply sites into the conventional-type self-oscillating polymer chain, the novel polymer chain caused aggregation-disaggregation self-oscillations in the solution. We clarified that the period of the self-oscillation of the novel self-oscillating polymer chain was proportional to the concentration of the malonic acid. Therefore, the concentration of the malonic acid can be determined by measuring the period of the novel self-oscillating polymer solution. In this review, we introduce the detailed molecular design of the novel self-oscillating polymer chain and its self-oscillating behavior. Moreover, we report an autonomous self-oscillating polymer gel actuator that causes a bending-stretching motion under the constant conditions.

The diffusion of polymer in long cylindrical tubes is investigated by using Monte Carlo simulations. Two kinds of cylindrical tubes are taken into account: (1) a homogeneous tube where the polymer-tube interaction is independent of monomer position along the longitudinal direction of the tube, and (2) a periodic one where the interaction is periodically changed along the tube. In the homogeneous tube, the diffusion coefficient along the longitudinal direction decreases with the decrease in the tube radius and decreases with the increase in the polymer-tube interaction. While in the periodic tube, the diffusion coefficient is further influenced by period length of potential. We find that the diffusion coefficient changes non-monotonically with the period length and the result can be attributed to the competition between polymer statistical size and period length of potential. The diffusion coefficient is relatively high when polymer size roughly matches the period length or when polymer size is much larger than the period length. [ABSTRACT FROM AUTHOR]

The Lees–Edwards boundary condition (LEbc) is widely used in particle-based simulation for producing shear flow. Application of traditional LEbc in dissipative particle dynamics (DPD) method may encounter certain problems, e.g. it will destroy the momentum conservation law at the near boundary region, and the coordinate system gives an incorrect end-to-end vector for polymer beads. Special treatments of the implementation of LEbc in DPD method are introduced in this paper. A single side ghost layer is used to keep the momentum conservation, and the global coordinate system is employed to obtain a correct calculation of the spring force between polymer beads. The simulation results give a good prediction of velocity profile and system temperature, and the elastic dumbbell model for current method can well represent the Oldroyd-B fluid. [ABSTRACT FROM AUTHOR]

Lithium ion-conducting membranes with poly(ethylene oxide) (PEO)/poly(vinylidene chloride-co-acrylonitrile) (PVdC-co-AN)/lithium perchlorate (LiClO) were prepared by solution casting method. Different plasticizers ethylene carbonate (EC), propylene carbonate (PC), gamma butyrolactone (gBL), diethyl carbonate (DEC), dimethyl carbonate (DMC), and dibutyl phthalate (DBP) were complexed with the fixed ratio of PEO/PVdC-co-AN/LiClO. The preparation and physical and electrochemical properties of the gel polymer electrolytes have been briefly elucidated in this paper. The maximum ionic conductivity value computed from the ac impedance spectroscopy is found to be 3 × 10 S cm for the EC-based system. From DBP-based system down to EC-based system, a decrease of crystallinity and an increase of amorphousity are depicted by X-ray diffraction technique, the decrease of band gap energy is picturized through UV-visible analysis, the decrease of glass transition temperature is perceived from differential scanning calorimetry plots, and the reduction of photoluminescence intensity is described through photoluminescence spectroscopy study at an excitation wavelength of 280 nm. Atomic force microscopic images of EC-based polymer electrolyte film show the escalation of micropores. Fourier transform infrared spectroscopy study supports the complex formation and the interaction between the polymers, salt, and plasticizer. The maximum thermal stability is obtained from thermogravimetry/differential thermal analysis, which is found to be 222 °C for the sample complexed with EC. The cyclic voltagram of the sample having a maximum ionic conductivity shows a small redox current at the anode, and cathode and the chemical stability is confirmed by linear sweep voltammetry. [ABSTRACT FROM AUTHOR]

We report a selective metal-vapor deposition phenomenon based on solvent printing and evaporation on polymer surfaces and propose a method to prepare fine metal patterns using maskless vacuum deposition. Evaporation of the solvent molecules from the surface caused large free volumes between surface polymer chains and resulted in high mobility of the chains, enhancing metal-vapor atom desorption from the surface. This phenomenon was applied to prepare metal patterns on the polymer surface using solvent printing and maskless metal vacuum deposition. Metal patterns with high resolution of micron scale were obtained for various metal species and semiconductor polymer substrates including poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] and poly(3-hexylthiophene-2,5-diyl). [ABSTRACT FROM AUTHOR]