Phase transition of asymmetric diblock copolymer induced by nanorods of different properties* *Project supported by the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi (Grant No. 2019L0957), the Key Research and Development Project of the Introduction of High-Level Scientific and Technological Talents in Lvliang (Grant No. 201701102), and the Shanxi Provincial Natural Science Foundation, China (Grant No.

Abstract

We investigate the microphase transition of asymmetric diblock copolymer induced by nanorods of different properties using cell dynamics simulation and Brown dynamics. The results show the phase diagram and representative nanostructures of the diblock copolymer nanocomposite. Various structures such as sea-island structure (SI), sea-island and lamellar structure (SI-L), and lamellar structure (L) are observed in the phase diagram. The system undergoes phase transition from SI-L to SI or from L to SI with increasing length of A-like sites for all numbers of nanorods except 10 and 300, and from SI to L with increasing number of nanorods for all lengths of A-like sites. Notably, the polymer system transforms from a tilted layered structure to a parallel lamellar, perpendicular lamellar, and subsequently sea-island structure with increasing length of A-like sites for a rod number of 240. To gain more detailed insight into these structural formation mechanisms, we analyze the evolution kinetics of the system with various lengths of A-like sites of the rods. The pattern evolution and domain growth of the ordered parallel/perpendicular lamellar structure are also investigated. Furthermore, the effects of the wetting strength, rod-rod interaction, polymerization degree, and length of nanorods on the self-assembled structure of asymmetric diblock copolymer/nanorods are studied. Our simulations provide theoretical guidance on the construction of complex-assembled structures and the design of novel functional materials.