Molecular Dynamics Simulation of Miscibility in Several Polymer Blends

TL;DR

This study uses Molecular Dynamics simulations to analyze the miscibility of various polymer blends, comparing simulation results with experimental data and other computational methods to understand their phase behavior.

Contribution

It introduces an atomistic simulation approach to determine the Flory-Huggins parameter for polymer blends and compares it with experimental and simpler computational methods.

Findings

Simulation results agree with experimental data on miscibility.

The Flory-Huggins parameter varies with temperature as predicted.

The method provides a detailed molecular-level understanding of blend interactions.

Abstract

The miscibility in several polymer blend mixtures (polymethylmethacrylate/polystyrene, (1,4-cis) polyisoprene/polystyrene, and polymethylmethacrylate/polyoxyethylene) has been investigated using Molecular Dynamics simulations for atomistic representations of the polymer chains. The trajectories obtained from simulation boxes representing the mixtures have been analyzed in terms of the collective scattering structure function. The Flory-Huggins parameter is determined from fits of the simulation results for this function to the random phase approximation expression. The numerical values of this parameter and its variation with temperature obtained with this procedure show a general qualitative and quantitative agreement with existing experimental data for the different systems. These results together with those previously obtained for the polyvylmethylether/polystyrene blends with the same method are compared with data yielded by other computational simpler approaches.