Structure-based Coarse Graining of Homopolymer Solutions: Designing the Implicit-Solvent Model with PRISM Theory

Implicit-solvent (IS) models are widely used in molecular simulations of polymer solutions, with the advantage of dramatically saving the amount of computation and the hope of faithfully reproducing some properties of the corresponding explicit-solvent (ES) model. In practice, however, an IS model often gives qualitatively different results from the corresponding ES model. In this work, we take a simple model system of homopolymer solutions as an example to examine the features of the effective pair potential between polymer segments in the IS model that is designed, using the well-developed polymer reference interaction site model (PRISM) theory, to reproduce the pair correlation functions between polymer segments in the corresponding ES model. To assess the accuracy of the PRISM theory, we also quantitatively compare its predictions with Monte Carlo simulation results.