Molecular Simulations and Mechanistic Analysis of the Effect of CO Sorption on Thermodynamics, Structure, and Local Dynamics of Molten Atactic Polystyrene.

A simulation strategy encompassing different scales was applied to the systematic study of the effects of CO uptake on the properties of atactic polystyrene (aPS) melts. The analysis accounted for the influence of temperature between 450 and 550 K, polymer molecular weights ( ) between 2100 and 31000 g/mol, and CO pressures up to 20 MPa on the volumetric, swelling, structural, and dynamic properties of the polymer as well as on the CO solubility and diffusivity by performing molecular dynamics (MD) simulations of the system in a fully atomistic representation. A hierarchical scheme was used for the generation of the higher polymer systems, which consisted of equilibration at a coarse-grained level of representation through efficient connectivity-altering Monte Carlo simulations, and reverse-mapping back to the atomistic representation, obtaining the configurations used for subsequent MD simulations.

Molecular Modeling Investigations of Sorption and Diffusion of Small Molecules in Glassy Polymers.

With a wide range of applications, from energy and environmental engineering, such as in gas separations and water purification, to biomedical engineering and packaging, glassy polymeric materials remain in the core of novel membrane and state-of the art barrier technologies. This review focuses on molecular simulation methodologies implemented for the study of sorption and diffusion of small molecules in dense glassy polymeric systems. Basic concepts are introduced and systematic methods for the generation of realistic polymer configurations are briefly presented.

Thermophysical properties of imidazolium tricyanomethanide ionic liquids: experiments and molecular simulation.

The low-viscous tricyanomethanide ([TCM](-))-based ionic liquids (ILs) are gaining increasing interest as attractive fluids for a variety of industrial applications. The thermophysical properties (density, viscosity, surface tension, electrical conductivity and self-diffusion coefficient) of the 1-alkyl-3-methylimidazolium tricyanomethanide [Cnmim][TCM] (n = 2, 4 and 6-8) IL series were experimentally measured over the temperature range from 288 to 363 K. Moreover, a classical force field optimized for the imidazolium-based [TCM](-) ILs was used to calculate their thermodynamic, structural and transport properties (density, surface tension, self-diffusion coefficients, viscosity) in the temperature range from 300 to 366 K.

Molecular simulations of imidazolium-based tricyanomethanide ionic liquids using an optimized classical force field.

Imidazolium-based ionic liquids (ILs) incorporating the tricyanomethanide ([TCM(-)]) anion are studied using an optimized classical force field. These ILs are very promising candidates for use in a wide range of cutting-edge technologies and, to our knowledge, it is the first time that this IL family is subject to a molecular simulation study with the use of a classical atomistic force field. The [C4mim(+)][TCM(-)] ionic liquid at 298.

Elucidation of the binding mechanism of renin using a wide array of computational techniques and biological assays.

We investigate the binding mechanism in renin complexes, involving three drugs (remikiren, zankiren and enalkiren) and one lead compound, which was selected after screening the ZINC database. For this purpose, we used ab initio methods (the effective fragment potential, the variational perturbation theory, the energy decomposition analysis, the atoms-in-molecules), docking, molecular dynamics, and the MM-PBSA method. A biological assay for the lead compound has been performed to validate the theoretical findings.

Coarse graining using pretabulated potentials: liquid benzene.

The large length and time scales involved in polymer simulation render the atomistic representation of polymer systems a computationally expensive and unnecessarily detailed procedure. We present a novel coarse-graining method for the description of nonbonded interactions between moieties composing the monomeric units of polymers, phenyl rings in particular. The method is based on the determination of the interactions between pairs of moieties from precalculated and tabulated values of the energy between the moieties in their atomistic representation.