Thermodynamically consistent coarse-grained models

The lack of thermodynamic consistency between various representations of a coarse-grained model has delayed the widespread use of coarse-grained models in engineering and material science, more …

A Langevin Equation 4 Protein Dynamics -> LE4PD

We utilize a multi-scale approach where molecular dynamic simulations are performed to obtain quantitative structural averages used as input to a coarse-grained Langevin Equation for Protein Dynamics, which can be solved analytically. More …




A Multichain Theory of Polymer Dynamics

The dynamics of polymer melts in both the unentangled and entangled regimes is described by a Langevin Equation for the correlated motion of a group of chains, which explicitly includes intramolecular and intermolecular interactions. Entanglements are accounted for by an intermonomer confining potential that has no effect on short chains, while interpolymer interactions, responsible for correlated motion and subdiffusive center-of-mass dynamics, are represented by an intermolecular center-of-mass potential derived from the Ornstein-Zernike equation. The calculated dynamic structure factor for polyethylene melts is found to be in quantitative agreement with Neutron Spin Echo experiments for polymers in a range of chain lengths that span unentangled and entangled dynamics (see figure on the left). The theory shows a progressive localization of the cooperative chain dynamics at the crossover from unentangled to the entangled regime, in the spirit of the reptation model. More …