All-Atom Molecular Dynamics Simulations of Poly(2,6-dimethyl-1,4-phenylene) Oxide: Validation of OPLS-AA Force Field for Conformational Behaviour in Vacuum and in Carbon Tetrachloride

OPLS force field has been successfully validated for poly(2,6-dimethyl-1,4-phenylene) oxide (PPO) in comparison with quantum chemical results and available experimental data. The formation of stable polymer solvent complexes, where solvent molecules are hosted in closed loops, has been detected in molecular dynamics (MD) simulations of OPLS all-atom (OPLS-AA) models of diluted solutions of PPO in CCl4. Estimations of free energy of solvation indicate an entropic stabilization of the polymer solvent complexes. A very high similarity of these structures with the intra-helical channels observed in the structure of PPO co-crystals suggests their possible role in the nucleation process inducing the crystallization of PPO from organic solvents.