Dissipative Particle Dynamics Simulation on Aggregation of Rod-Coil-Rod Triblock Copolymer in Dilute Solution

The aggregate morphology of rod-coil-rod copolymers in a dilute solution was investigated by dissipative particle dynamics simulations. The influences of the mutual compatibility between rod and coil blocks, the solvent property, the coil length, and the copolymer concentration on the aggregate structure were studied in detail. The simulation results show that the increase of the mutual compatibility between rod and coil blocks induces transformation of the aggregate morphology from spherical, to onionlike, to cage-like, and ultimately to cylindrical. With the increase in the hydrophobicity of the coil block, the cagelike aggregate changes into an onion-like aggregate, then a patchy aggregate, and then an inverted onionlike aggregate. Finally, a phase diagram of the rod-coil-rod triblock copolymers as a function of the coil length and the copolymer concentration is presented. It shows that cage aggregates are easily formed when the coil length is long and the concentration is relatively low, whereas onionlike aggregates are preferred when the coil length is short and the concentration is moderately low.