Dissipative Particle Dynamics Simulations Of The Self-assembly Of Rod-coil Block Copolymer In Solution

The rod-coil block copolymers have the ability of self-assembly intosupramolecular structures and have advanced applications in polymersynthesize technology、 nanostructure materials and optoelectronicmaterial. The self-assembly of rod-coil block copolymer is different fromthat of coil-coil copolymer due to the effect of chain topology onconformational entropy and the anisotropy and orientation of rods inaddition. The rod-coil copolymer can form well-ordered structures inspite of low molecular weight. A number of works have focused on thephase behavior of rod-coil block copolymer in recent years. In this paper,we study the self-assembly and phase behavior of rod-coil copolyemer insolution with the dissipative particle dynamics simulation method.Firstly we study three different kinds of topology structure ofrod-coil block copolymer in bulk and in coil-selective solution throughvarying the concentration of rod–coil block copolymer. We focus onthree types of rod-coil copolymer: linearl-R₅C₅, cyclicc-R₅C₅,middletetheredm-R₅C₅in solution. The observed micellar structures include:cylinders、spheres、 lamellae and inverted hollow cylinders. Thesemorphologies are associated with the topology structure、 solventselectivity and the polymer concentration. The rod block tends to orientitself relative to other rod blocks and this causes the energy decrease, sothe self–assembly morphology depend on the competition between the orientation of rods and the conformation entropy of the chain stretch.Using the dissipative particle dynamics simulation method, we havestudied the self-assembly of the blends of rod-coil block copolymer andhomopolymer in selective solution. The diverse morphologies such asdouble cylinder, lamella, lamella and cylinder mixed, inversed hollowcylinder are observed with varying the concentration of homopolymer.The anisotropy and orientation of rods, and the entropy caused by thestretch of coils can influence the morphology of aggregates. The densitygraph of homopolymer and block copolymer blends is shown that thehomopolymer aggregates in the core of cylinder when the concentrationof homopolymer is low.