A comparison of Y-, H-, and π-shaped diblock copolymers via dissipative particle dynamics

The phase behaviors, molecular conformations, and structural length scales of Y- (AB(2)) H- (B(2)AB(2) and pi-shaped [B(A)B(A)B] copolymers are compared using dissipative particle dynamics. Though their phase diagrams are similar, the stability of microstructures is enhanced with increasing complexity of molecular sarchitecture (linear -> Y -> H or pi). In addition, the greater entropy loss associated with the disorder-to-order transition for H and pi architectures makes it more difficult for them to undergo a microphase separation. When the H and pi molecules pack to form an ordered structure, due to the significant presence of the chains in a bridge conformation, the structural length scales are strongly restricted.