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

Abstract

OPLS force field has been successfully validated for PPO in comparison with quantum chemical DFT 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 simulations of 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.This article is protected by copyright. All rights reserved

Crystallinity and Melting of Functionalized Poly(2,6-dimethyl-1,4-phenylene) oxide (PPO)

“…This side-group insertion into the intrahelical channels would maintain energetic feasibility of packing of the large-diameter PPO helices, even after high degrees of polymer functionalization. Meanwhile, intrahelical insertion of the side groups could stabilize crystalline helices by host–guest nonbonded interactions, like those occurring in CC PPO phases …”

“…Meanwhile, intrahelical insertion of the side groups could stabilize crystalline helices by host−guest nonbonded interactions, like those occurring in CC PPO phases. 53 Projections, along (A) and perpendicular (A′) to the helical axis of the large-diameter helix, which was proposed for the NC α form of PPO, 52 is shown in Figure 7. The same projections of this large-diameter helix, when it hosts a few chloroacetyl side groups (DF ≈ 17 mol %), is shown in Figures 7B,B′.…”

All-atom molecular dynamics simulations of polymer and polyelectrolyte brushes

“…Many research groups including ours use the OPLS-AA forcefield to model polymeric systems. 97–100 To explicitly model the solvent water there are many kinds of models: SPC, SPC/E, TIP4P, TIP3P, etc. The water models are generally parameterized to reproduce the following experimental quantities: static dielectric constant, self-diffusion coefficient, thermal expansion coefficient, and isobaric heat capacity.…”