A coarse-grained model for particle dynamics simulations of complex fluids

We have devised a ‘soft-attractive-and-repulsive’ pair-potential model, which has a hardness parameter (β) besides energy and length parameters, to adopt three coarse-graining procedures for soft-matter. Namely, (i) Grouping for a monomer or segment; (ii) Packing for a group of molecules; and (iii) Time-averaging to take account of effective potential over a time-span. The resulting models are capable of reproducing liquid–vapor coexistence curves of real fluids at various coarse-grained levels. A model with β=3.0 is analytically representing a time-averaged effective potential over a long time-span. Its combination with Dissipative Particle Dynamics method allows us to reproduce dynamic properties for complex fluids.