Can pure polymer liquids be represented at two different resolutions simultaneously?

Abstract

Given that the physical properties of polymeric liquids extend on a wide range of length scales, it is computationally convenient to represent them by coarse-grained descriptions at various granularities to investigate local and global properties simultaneously. We use the Integral Equation Coarse-Graining (IECG) theory for a mixture of two species with various resolutions representing polyethylene polymeric liquids and derive interacting potentials that ensure consistencies of relevant thermodynamical and structural properties. These properties are in agreement with the corresponding atomistic resolution description. The composition, temperature, and density dependences of such mixed resolution potentials are investigated numerically and analytically. In the limit of long polymer chains, where Markovian statistics is obeyed, the potentials are analytically solved and decay with characteristic scaling exponents that depend on the mixture composition and CG resolution of the two components. The implications of the effective IECG potentials are also discussed for multiresolution simulation approaches.