Title: Shape-Switchable Liquid-Crystal Polymer Actuators with Light-Induced Shape Memory Effect

Author: Jinlei Wang, Feng Pan, Xiaojun Liu, Lang Qin*, Yanlei Yu

Journal: ACS Appl. Mater. Interfaces, 2025, 17, 48815−48823

Abstract:

The initial shape of a soft actuator plays a vital role in its functional performance as it dictates the internal stress distribution and deformation pathway during the actuation process. Photodeformable liquid-crystal polymers (LCPs) have demonstrated significant potential in soft actuators due to their fast, localized, precise, and reversible deformation under light irradiation. However, the initial shape of LCP actuators is generally nonswitchable once fabricated, limiting them to a single deformation mode and monofunctionality. Herein, we present a strategy for fabricating shape-switchable LCP actuators by integrating an athermal light-induced shape memory effect (SME) into photodeformable LCP systems. The reversible photodimerization of coumarins introduces an additional crosslinking network that regulates the mobility of molecular chains, enabling LCPs to exhibit a light-induced SME for shape-switching. Moreover, the photothermal effect of disperse red 1 acrylate induces mesogen alignment changes under 470 nm light irradiation, allowing for the independent actuation of each switched shape. Leveraging this unique shape-switching mechanism, we fabricated a soft actuator capable of transforming among multiple motion modes, including rolling, crawling, and gripping, for the first time. This study establishes a novel design paradigm for developing multimorphology and multifunctional soft actuators, advancing the complexity and versatility of LCP-based intelligent systems.

Fulltext Link：https://pubs.acs.org/doi/10.1021/acsami.5c12533

The initial shape of soft actuators is crucial to their functional performance, as it determines the internal stress distribution and deformation pathway during actuation. Photoresponsive liquid crystal polymers (LCPs) have demonstrated great potential in soft actuators owing to their rapid, localized, precise, and reversible deformation capabilities under light irradiation. However, conventional LCP actuators, once fabricated, possess a fixed initial shape that cannot be switched, thereby restricting them to a single deformation mode and a single function. Here, we propose a strategy to construct shape-switchable LCP actuators by incorporating a non-thermal light-induced shape memory effect into the photoresponsive LCP system. The reversible photodimerization of coumarin moieties introduces an additional crosslinked network that can modulate the chain mobility of the polymer, endowing the LCP with light-induced shape memory functionality for shape switching. Moreover, the photothermal effect of Disperse Red 1 acrylate can induce changes in the alignment of mesogens under 470 nm light, enabling independent actuation of various shape-switched configurations. Leveraging this unique shape-switching mechanism, we report for the first time soft actuators capable of transitioning among multiple locomotion modes, including rolling, crawling, and grasping. This study establishes a new design paradigm for developing multi-morphology and multifunctional soft actuators, thereby enhancing the complexity and versatility of LCP-based intelligent systems.