A Coarse-Grained Force Field for Molecular Dynamics Simulation of (High Molar Mass) Atactic Polystyrene

VARTORELLI, M.R.; VEGA, J.R.

Heredia

Simposio; XII Simposio Latinoamericano de Polímeros SLAP 2010 - X Congreso Iberoamericano de Polímeros; 2010

Molecular dynamics (MD) is a simulation technique based on a semi-empirical parameterized force field: an analytical expression for the potential energy, V(r), which accounts for every kind of interactions (bonds, angles, torsions, electrostatics, etc.). Through MD, a large amount of microscopic information is gathered from atomistic simulations; and then macroscopic properties of the system can be derived from the ensemble averages, provided that the ergodicity of the sampled phase space can be ensured. Melts or solutions of high molecular weight polymers are difficult to be simulated at atomic scale by MD, due to the large amount of degrees of freedom. In general, MD simulations are used to investigate time- and space-windows in the nanometer scale. A huge effort is required to get information at mesoscopic scale (in between the microscopic and macroscopic levels); e.g., to describe processes like diffusion rates, conformational changes kinetics, or entanglement dynamics of polymers.