Shining Liquid Crystal Elastomer Material: The Balance of Micro-Rigidity and Macro-Elasticity and the Inherent Mechanism

Polymeric room-temperature phosphorescent (RTP) materials have attracted considerable attention due to their impressive luminescence behaviors. However, most polymer matrices are rigid materials, the lack of flexibility has been hindering the development of multi-functional RTP materials. In this work, a new phosphorescent liquid crystal elastomer was prepared, which could not only emit RTP but also show temperature-responsive elastic behavior. LQ-4TPA has a lifetime of 532 ms and an afterglow of 3 s observed by the naked eye with the elongation at break high up to 315%. The hydrostatic pressure results demonstrate that the liquid crystal framework is the key component for RTP emission. Excitingly, this work also reveals the inherent mechanism of a rigid environment that the volume of chromophores and matching interaction with the polymeric network play important roles in achieving excellent RTP performance in the liquid crystal elastomer material. After the uniaxially aligned program, the monodomain liquid crystal elastomer presented a reversible shape actuation character. Thus, the biomimetic liquid crystal flower and smart liquid crystal gripper were successfully programmed and could contract and elongate regularly under different temperatures, demonstrating the extended applications of RTP material with the combination of RTP performance and temperature-dependent elastic deformation.