Molecular dynamics simulations of athermal polymer blends: Comparison with integral equation theory

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Abstract
Molecular dynamics simulations of a binary, athermal blend of chains consisting of 50 sites were carried out over a range of compositions at an overall packing fraction of 0.465. The species in the blend interact with Lennard‐Jones repulsive interactions chosen to give effective hard core diameters of 1.015 and 1.215 for the A and B sites, respectively. The intramolecular structure of the chains was seen to be weakly dependent on composition, with the mean‐square end‐to‐end distance of the minority component at low volume fractions tending towards that of the host component. The three intermolecular radial distribution functionsg AA (r), g BB (r), and g AB (r) were observed to increase with increasing concentrations of the A chains. Polymer reference interaction site model (PRISM) calculations were performed on this same blend and very good agreement was found between the theory and the simulation over a range of compositions. Significant nonrandom mixing was observed from the molecular dynamics simulations on local length scales; PRISM theory was able to accurately predict these nonrandom local features in the packing.