Self-assembly of π-shaped copolymers

Abstract

Dissipative particle dynamics (DPD) simulation is employed to examine the self-assembly of π-shaped copolymers possessing rigid backbones (rod blocks A) and two flexible (coiled) side chains B in a selective solvent. The dependence of the morphologies of the nanostructures generated on the positions of the junction points of the two side chains on the rod block, on the concentration of the copolymer, on the nature of the solvent, as well as on the repulsive interactions between the two coiled side chains B and the rod blocks A of the copolymer, was investigated. Nanostructures (such as interacting micelles, multicore micelles, nanocages, nanotires) of various shapes were identified. In addition, stacked disks with the two-dimensional sequence BAAB were observed. By varying the selectivity of the solvent for coils B, one can change the internal structure of the self-assemblies. The coil-block cages can be changed in rod-block cages by varying the selectivity of the solvent for the coil blocks B and/or by modifying the interaction between the coil blocks and rod blocks. The kinetics of formation of nanotires and of the two kinds of cages are also examined.