The thermal conductivity of the crystalline delta phase of syndiotactic polystyrene has been investigated by reverse nonequilibrium molecular dynamics simulations. The results are in the expected range. An anisotropy is found for the thermal conductivity, with the component in chain direction being 2.5-3 larger than perpendicular to it. Any increase in the density causes an increase also in the thermal conductivity, particularly in the perpendicular directions. As side results, the simulations confirm an earlier finding on the force field dependence of the thermal conductivity: The thermal conductivity has a tendency to decrease when the number of active degrees of freedom in the system is reduced by the introduction of constraints. This dependence is, however, weaker and more erratic than previously found for molecular liquids and amorphous polymers.

We studied the thermal diffusion behavior of equimolar mixtures of hydrocarbon chains in cyclohexane, p-xylene and o-xylene experimentally and by reverse nonequilibrium molecular dynamics.The hydrocarbon chains heptane, 2,3-dimethylpentane, 2,4-dimethylpentane, 2-ethyl 3 methyl butadiene and 2,4 dimethylpentadiene -1,3 with the same number of carbon atoms were considered in order to conserve the mass contribution and to investigate the shape influence on the Soret coefficient. Compared to the experimental data, the simulation results show the same trend. With increasing degree of branching the Soret coefficient becomes larger. The negative Soret coefficient of the hydrocarbon chains indicates the enrichment in the warm side. We were able to find a empirical correlation between the properties of the pure components and the Soret coeffcients of the mixture.

MD studies of liquid isopropyl alcohol and melts of short poly(vinyl alcohol) (PVA) oligomers are described. The specific volume was found to depend inversely on the number N of repeat units. If the chain length is enhanced, the viscosity of the PVA melt increases and the peaks in the radial distribution function become sharper. Additional peaks that appear in melts of PVA chains are of pure intramolecular origin. The calculated radius of gyration was found to depend on the number of formula units via $N^{0.65 \pm 0.03}$. The orientation correlation functions showed that all molecular vectors of PVA melts with chain lengths N = 1, 2, 3 relax completely within a few nanoseconds. The relaxation times for the OH bond vector as obtained via the Kohlrausch‐Williams‐Watts expression showed an exponential dependence on the number of repeat units.magnified image

Ensemble growth Monte Carlo (EGMC) and dynamic Monte Carlo (DMC) simulations are used to study sequential folding and thermodynamic stability of hydrophobic-polar (HP) chains that fold to a compact structure. Molecularly imprinted cavities are modeled as hard walls having sites that are attractive to specific polar residues on the chain. Using EGMC simulation, we find that the folded conformation can be stabilized using a small number of carefully selected residue-specific sites while a random selection of surface-bound residues may only slightly contribute toward stabilizing the folded conformation, and in some cases may hinder the folding of the chain. DMC simulations of the surface-bound chain confirm increased stability of the folded conformation over a free chain. However, a different trend of the equilibrium population of folded chains as a function of residue-external site interactions is predicted with the two simulation methods.