Self-Assembly of Linear ABCBA Pentablock Terpolymers

Abstract

The phase behavior of linear ABCBA pentablock terpolymers is examined and compared with corresponding linear ABC triblock terpolymers by using the 3-D self-consistent field theory. In particular, phase diagrams of the melts are constructed and used to discuss how the self-assembled morphologies are influenced by the compositions of the three components and the block number per chain. Since the two free ends of A blocks in the ABCBA copolymers enable the macromolecules to relieve the packing frustration within the structures as well as more types of chain conformation, the ABCBA pentablocks exhibit diverse complex network structures and binary crystalline phases of cylinders and spheres. Compared with most linear diblock and triblock copolymers, for which the gyroid phase occupies a narrow region in the phase space, the ABCBA pentablocks tend to form a variety of continuous networks including diamond, hexagonally perforated lamellae, Fddd network, and gyroid. Moreover, the ABCBA pentablocks exhibit differe...