Using soft potentials for the simulation of block copolymer morphologies

A simulation strategy for the creation of equilibrated nanostructured copolymer melt morphologies is proposed. Molecular dynamics simulations of bead-spring chains with a soft pair potential are used for efficient modeling of phase separation, while preserving Gaussian chain statistics and chain conformations of an underlying microscopic model. In a second step, hard excluded volume interactions are reintroduced that match the copolymer segregation strength but only require reequilibration of local packing structure. We show that substantial computational gains can be achieved for equilibrating moderately entangled bead-spring polymers. The resultant configurations can be used for further studies of structural and mechanical properties in melts or glasses.