Controlled Deformation Mode and Amplitude of Liquid Crystal Actuators Through Orthogonal Light and Heat-Induced Exchanges

Abstract

Liquid crystal elastomers (LCEs) are versatile soft actuators known for their flexible texture, low density, and ability to undergo reversible deformations that mimic the behavior of skeletal muscles. These properties make them highly attractive for applications in exoskeletons, soft robotics, and medical devices. However, their functionality is typically limited to simple and discontinuous deformations. This study introduces a novel structural design that enables precise control of both the mode and amplitude of deformation. This design integrates photo-reactive o-nitrobenzyl moieties and temperature-dependent hydrogen bonds into the LCE structure. The o-nitrobenzyl moieties enable irreversible reconfiguration of the LCE crosslinked network through photoreactions, allowing for easy alignment and reshaping of the material. Meanwhile, the hydrogen bonds act as “temperature-dependent locks”, regulating the mobility of polymer chains during thermal deformation. By adjusting the heating temperature, the deformation amplitude can be finely tuned across a wide range (0%–103%). The synergy of these two mechanisms—light-induced irreversible reconfiguration and temperature-induced reversible H-bond exchanges—empowers LCEs to achieve customizable and continuous deformations. This represents a significant advancement in bridging the gap between synthetic actuators and biological motion systems.