Towards Multi-Responsive and Autonomous Soft Actuators Based on Liquid Crystal Elastomers

Abstract

Inspiration from nature has long guided the development of materials that do more than simply exist. Living systems autonomously adapt, move, and respond to their surroundings through a delicate balance between structure, energy, and environment. Recreating even a small part of this complexity in synthetic matter remains a central challenge in materials science. Stimuli-responsive materials offer one possible route, as they can convert external input, such as light, heat, or magnetic fields, into macroscopic functionalities, including mechanical motion. Among them, liquid crystal elastomers (LCEs) stand out for their ability to couple molecular order with macroscopic elasticity, enabling reversible and tunable shape changes. Their versatile responsiveness makes them an ideal platform for exploring synthetic materials with life-inspired functions.

This thesis advances this vision by studying how LCEs can express different life-inspired functionalities, in particular multi-responsiveness, biomimetic shape changes, and autonomy. Through material design, stimuli integration, and geometric programming, LCEs are shown to evolve from simple, externally driven actuation toward coordinated, self-sustained motions. Multi-responsive functionality is achieved by combining optical and magnetic stimuli within a single material, enabling versatile control and operation in aqueous environments. Controlled shape changes are demonstrated through spatiotemporally programmed light actuation, producing wave-like deformations reminiscent of biological motion. Autonomy is realized in a light-powered self-oscillating system, where intrinsic feedback between deformation, illumination, and heat dissipation sustains rhythmic motion under constant energy input. Collectively, these findings illustrate how LCEs can serve as a platform to translate behaviors observed in nature into the realm of synthetic soft materials.