A cosolvency effect on tunable thermosensitive core-shell nanoparticle gels.

The influence of co-solvents on the swelling behavior of tunable thermosensitive core-shell nanoparticle gels was investigated. The poly(methyl methacrylate) (PMMA) core and poly(2-hydroxyethyl methacrylate) (PHEMA) shell network in 1-propanol reacted differently upon the addition of three co-solvents (cyclohexane (CHX), 1,3-propanediol (PDO), and water), resulting in highly controllable swelling properties of the core-shell gels. In particular, a strongly enhanced solvation effect, called the cosolvency phenomenon, occurred even with a very small amount of water (1-3 wt%).

Ab initio potential energy surface for methane and carbon dioxide and application to vapor-liquid coexistence.

A six-dimensional intermolecular potential energy surface for a rigid methane (CH4) and carbon dioxide (CO2) dimer was developed from the counterpoise-corrected supermolecular approach at the CCSD(T) level of theory. A total of 466 grid points distributed to 46 orientations were calculated from the complete basis set limit extrapolation based on up to aug-cc-pVQZ basis set. A modified site-site pair potential function was proposed for rapid representation of the high level ab initio calculations.

Molecular thermodynamic analysis for assessing the relationship between reentrant swelling behavior and ternary liquid-liquid equilibrium for poly(N-isopropylacrylamide) nanometer-sized gel particles in a water-tetrahydrofuran cosolvent system.

The influence of phase separation on swelling behavior was investigated based on the thermodynamic framework of reswelling phenomena. The cloud-point for a ternary system of water(1)-tetrahydrofuran (THF)(2)-poly(N-isopropylacrylamide)(3) was examined by thermo-optical analysis (TOA). Nanometer-sized N-isopropylacrylamide (NIPA) gel particles were prepared by precipitation polymerization, and their swelling behaviors were determined using photon correlation spectroscopy (PCS).

Understanding liquid mixture phase miscibility via pair energy parameter behaviors with respect to temperatures determined from molecular simulations.

The miscibility behaviors of binary liquid mixtures were studied by a combination of molecular simulations and thermodynamic theories. Pairwise interaction parameters were obtained from molecular simulations that accounted for the effect of temperature. From a thermodynamic perspective, different types of liquid-liquid equilibrium (LLE) and different degrees of miscibility can be expressed in terms of energy behaviors with respect to temperature.

Theoretical consideration of osmotic pressure in aqueous protein/salt systems based on extended hard core Lennard-Jones potential.

A simple and analytical pair potential function was developed to represent the osmotic pressures in aqueous protein/salt systems under various conditions. Based on a hard core Lennard-Jones (HCLJ) potential model, the new potential function considers various interactions by extending the attractive Lennard-Jones potential. A temperature-dependent coefficient term was introduced to take into account the specific properties of given materials.

Phase equilibrium calculations of ternary liquid mixtures with binary interaction parameters and molecular size parameters determined from molecular dynamics.

The method presented in this paper was developed to predict liquid-liquid equilibria in ternary liquid mixtures by using a combination of a thermodynamic model and molecular dynamics simulations. In general, common classical thermodynamic models have many parameters which are determined by fitting a model with experimental data. This proposed method, however, provides a simple procedure for calculating liquid-liquid equilibria utilizing binary interaction parameters and molecular size parameters determined from molecular dynamics simulations.

The dependence of the electrochemical properties of perfluorosulfonic acid membrane/water systems on repeat unit structure.

We developed a molecular thermodynamic framework to describe the dependence of the electrochemical properties of a perfluorosulfonic acid (PFSA) membrane/water system on the polymer structure. To better understand the behavior of the polymer membrane/water system, we developed a lattice model based on lattice cluster theory. We performed hypothetical calculations for a variety of repeat unit structures.

Phase behaviors of polymer solutions using molecular simulation technique.

Phase behaviors of polymer solutions are estimated using a combination of thermodynamic models and molecular simulation technique. In general, many parameters of binary systems are determined by fitting a thermodynamic model with experimental data. In this study, we obtained all parameters using molecular simulation.

Novel core-shell-structured Li[(Ni0.8Co0.2)0.8(Ni0.5Mn0.5)0.2]O2 via coprecipitation as positive electrode material for lithium secondary batteries.

We have successfully synthesized a spherical core-shell structure based on Li[(Ni0.8Co0.2)0.

Cloud-point temperatures of lysozyme in electrolyte solutions by thermooptical analysis technique.

Liquid-liquid phase-separation data are obtained for aqueous solutions of lysozyme. Thermooptical analysis (TOA) technique overcomes many defects of the light scattering method, which is most commonly used for this purpose, and provides a simple, rapid and reliable experimental method to determine cloud-point temperatures (CPTs) of aqueous protein solution systems. The TOA apparatus described here needs very small amount of samples (0.

Lysozyme-lysozyme and lysozyme-salt interactions in the aqueous saline solution: a new square-well potential.

We investigate lysozyme-lysozyme and lysozyme-salt interactions in electrolyte solutions using a molecular-thermodynamic model. An equation of state based on the statistical mechanical perturbation theory is applied to describe the interactions. The perturbation term includes a new square-well potential of mean force, which implies the information about the lysozyme surface and salt type.

Salting-out in the aqueous single-protein solution: the effect of shape factor.

A molecular-thermodynamic model is developed to describe salt-induced protein precipitation. The protein-protein interaction goes through the potential of mean force. An equation of state is derived based on the generalized van der Waals partition function.

Theory for the capillary electrophoretic separation of DNA in polymer solutions.

We present a mathematical model based on the models of Hubert et al. [Macromolecules 29 (1996) 1006] and Sunada and Blanch [Electrophoresis, 19 (1998) 3128] to describe the electrophoretic mobility of DNA by a transient entanglement coupling mechanism. The proposed model takes into account the interactions between molecules in the capillary and the cross-section of collision between DNA and polymer molecules.