Defect-Induced Order–Order Phase Transition in Triblock Copolymer Thin Films

Abstract

When a cylinder forming triblock copolymer thin film is exposed to supercritical carbon dioxide (scCO2), the system suffers an order–order phase transition from parallel (C∥) to perpendicularly oriented cylinders (C⊥). Here, we found that, during the phase transition, defects modify the energetic barriers for nucleation and provide a strong orientational correlation between the configurations of stable and unstable phases. The topological defects in the primitive phase survive the transition, and its population provides a lower bound for the density of defects in the post-transitional phase. Results, based on experiments and mean-field theory, show that control over the orientational order in the primitive phase can be used to manipulate order and defects in the transversely isotropic hexagonal pattern.

Skyrmion fluid and bimeron glass protected by a chiral spin liquid on a kagome lattice

“…In particular, the patterns of Fig. 5 are reminiscent of the intermediate dynamical regime in the order-order transition of copolymer thin films [52]. These connections between skyrmions and other branches of physics are promising, and further work is needed to investigate this peculiar type of glass, made of zero-and one-dimensional topological defects.…”