Dynamic Programme Locking of Isomerization Behavior of Molecular Switch in Liquid Crystal Elastomers

Abstract The reversible isomerization behavior of molecular switches in liquid crystal elastomers (LCEs) usually only can be monotonically repeated, because the molecular motion environment is the same for each isomerization cycle in a permanently cross‐linked polymer network. Therefore, achieving a tunable photostationary state (PSS) in the same LCE material system is a significant challenge. Herein, a spiropyran‐based material (SPBM) as the molecular switch is introduced into a LCE system, which constructed a typical photo‐responsive material with reversible isomerization behavior. Furthermore, dynamic cross‐linked polymer networks via diselenide bonds endow the SPBM in this system with a tunable molecular motion environment, which switches freely or restrictedly depending on the size of the free volume. Thus, the molecular switch can endow the LCE with programmable photo‐response, and a program locking or unlocking is enabled by tuning the free volume. This post‐programming locking (PPL) strategy may offer a new sight for promoting the higher controllability of the stimulus‐responsive behavior of the smart materials.