Enhancement of Defect Annihilation in Self-Assembled Block Copolymer Nanostructures

Abstract

The self-assembly of block copolymers usually suffers from dense structural defects. The defects are spontaneously formed in the process of nanostructure formation, and their annihilation is strongly suppressed due to significant energy barrier for polymer chain diffusion and structural reorganization. With the careful introduction of self-consistent mean field method, I have studied how the mixing of solvents or short random copolymers can enhance the long range order of block copolymers. Especially, one theory/experiment collaboration demonstrates that in the block copolymer nanostructure the neutral random copolymer chains are localized at defect cores. It is shown that the localized disordered state at defect cores greatly relieves the energy penalty for the chain diffusion and lamellar reorganization, and thus they trigger anomalously large grain growth of lamellar morphology in the block copolymer thin films.