Self-assembling behavior of block copolymers involving competing length scales

This paper highlights our recent results concerning the self-assembling behavior of block copolymers, in which two length-scale-ordering morphologies are involved, by employing the dissipative particle dynamics (DPD) method. In particular, two molecular architectures by combining an A-homopolymer block with a BC-comb block or a BC-alternating block, which are referred as A-block-(B-graft-C) and A2-star-(B-alt-C), respectively, are examined. Generally speaking, as long as the three components are significantly incompatible one another, various types of hierarchical structures, such as spheres-within-lamellae, cylinders-within-lamellae, gyroid-within-lamellae, lamellae-within-lamellae, lamellae-within-cylinders, and lamellae-within-spheres, can be formed in both molecular architectures. However, they exhibit a completely different packing behavior of molecules due to the difference of molecular architecture. In particular, the small-length-scale lamellae formed by the B-alt-C and B-graft-C chains display a parallel and perpendicular direction, respectively, with respect to the large-length-scale structure. We believe this characteristic difference could impose different influences upon various properties of polymers, such as photoelectronic properties, and lead to different potential applications.