Light-Fueled Self-Sustained Soft Robotics

Abstract

Incorporating feedback mechanisms into stimuli-responsive materials enables self-sustained motion, an archetypal non-equilibrium behavior mirroring the autonomy of biological systems. Among synthetic materials, light-responsive liquid crystal elastomers (LCEs) have emerged as a paradigm for achieving such dynamics through self-shadowing effect, where structural deformation modulates light absorption to create feedback loops. This process transforms light from a mere trigger into a continuous energy reservoir, driving spontaneous oscillations. Yet, these systems face critical limitations: limited motion amplitudes, reciprocal actuation cycles, and a decoupling of material–environment interactions.

This thesis systematically addresses these challenges posed by light-fueled self-oscillating LCE systems by exploring three interconnected frontiers: actuation mechanisms, non-reciprocal symmetry breaking, and sensing capabilities. First, force-assisted oscillation and zero-elastic-energy modes (ZEEMs) bypass kinematic restrictions observed in self-shadowing-induced oscillation. By integrating external force fields or engineering mechanical frustration, these systems achieve large- amplitude rotations and spontaneous motion under uniform illumination. Second, non-reciprocal symmetry breaking unlocks functionalities in fluid environments. Piecewise self-oscillators actuated by orthogonally aligned laser beams exhibit programmable non-reciprocal patterns, facilitating directional fluid pumping. ZEEMs toroidal architectures exploit geometric frustration to break symmetry, yielding navigated swimming in Stokes regime. Finally, these systems acquire sensing-like environmental interaction, including mechanosensitive tuning under load, hydrodynamic communication between oscillators, and boundary-guided directional adaptation—collectively bridging the gap between synthetic and biological autonomy. Through these advances, this thesis offers new insights into designing synthetic matter that merges non-equilibrium actuation with environmental adaptability.