Secondary super-structures in random copolymers

Secondary domain superstructures in correlated random block copolymers are considered theoretically using the concept of the second order parameter re lated to fluctuations of the local mean block length. It is shown that the size of secondary domains, Lambda, is much larger than the primary domain s ize, L: Lambda proportional to epsilon(-1), while L proportional to epsilon (-1/2), where epsilon is a small parameter defining the composition asymmet ry. Different secondary morphologies are characterized. It is also shown th at separation of the system in two macroscopic phases with different primar y morphologies predicted earlier using the free energy expansion up to psi( 4) (psi is the usual order parameter related to local composition) is an ar tifact of this widely accepted theoretical model.