Nanostructure formation in polymer thin films: Dissipative particle dynamics simulation using a space-time coarse-grained model

We have devised a soft-attractive-and-repulsive pair-potential model, which has a hardness parameter (beta) and a smooth cut-off, to adopt coarse-graining procedures for soft-matter. A model with beta=3.0 analytically represents a time-averaged U-eff(r) over a long time-span, and gives excellent energy conservation at a very long time-step. In this work, we extended our model to represent copolymer systems, and combined it with dissipative particle dynamics (DPD) method. We have performed DPD simulations to study the nano-pattern formation in symmetric block copolymer film, and found that the simulated surface structures resembled those patterns observed in experiment of copolymers thin films on a solid substrate.