Visible Light-Responsive Covalent Adaptable Liquid Crystal Elastomers Enabled by Dynamic Allyl Selenide Bonds

Abstract

Liquid crystal elastomers (LCEs) are excellent polymer materials for a wide range of applications, including soft actuators and shape memory materials. At present, some dynamic covalent bonds (DCBs) have been introduced into LCEs to achieve reprogrammability. However, the contradiction between reprogrammability and stable actuation performance is still a challenge. One of the solutions is to introduce photoactivated DCBs into thermotropic LCEs to maintain their thermal adaptability. Therefore, it is meaningful to find a DCB with thermal stability and mild photoresponse for application in thermotropic LCEs. Herein, we adopt dynamic chemistry of allyl selenide, which not only achieves the separation of network reconfiguration conditions (light) from LC phase transition conditions (heat) but also achieves multiple network reconfiguration of LCEs under visible light conditions (405−450 nm). This dynamic covalent chemistry with mild stimulation conditions and sustainable dynamic exchange capability offers great possibilities for the application and design of covalently adaptable LCEs.

Understanding the application of covalent adaptable networks in self-repair materials based on molecular simulation

“…18–22 In contrast to traditional polymers, CANs demonstrate outstanding solvent resistance, mechanical properties, and reprocessability. These materials find wide applications in areas such as stimuli responsiveness, 23–25 shape memory, 26–28 molecular transport, 29–31 etc. According to the reaction mechanism, CANs can be further classified into dissociative CANs (Diss-CANs) and associative CANs (Asso-CANs, also known as vitrimers).…”