  A soft particle model for diblock (AB) copolymer melts is proposed. Each
molecule is mapped onto two soft spheres built by Gaussian A- and B-monomer
distributions. An approximate analytical expression for the joint distribution
function for the distance between both spheres and their radii of gyration is
derived, which determines the entropic contribution to the intramolecular free
energy. Adding a mean-field expression for the intermolecular interactions, we
obtain the total free energy of the system. Based on this free energy, Monte
Carlo simulations are carried out to study the kinetics of microphase ordering
in the bulk and its effect on molecular diffusion. This is followed by an
analysis of thin films with emphasis on pattern transfer from walls with a
periodic structure. It is shown that the level of coarse graining in the soft
particle model is suitable to describe structural and kinetic properties of
copolymers on mesoscopic scales.
