지속적 운동 가능한 자극-반응성 액정 엘라스토머 액추에이터 개발 및 응용

Abstract

Soft robotics has been gaining significant attention across various fields due to its potential for creating bio-mimetic and micro-scale actuators. In contrast to traditional rigid robots, soft robots possess deformable, flexible bodies that can take on different shapes and be miniaturized to sizes as small as centimeters or even smaller. Among various stimuli-responsive materials, liquid crystal elastomers (LCEs), which has their remarkable anisotropy, have become highly sought-after materials for soft robotics due to their capable of fast, powerful, reversible and controllable responsiveness. LCEs exhibit a nematic-isotropic phase transition property, allowing their oriented mesogen to reversibly respond to various stimuli such as heat, light, chemicals, resulting in macroscopic deformations like bending and twisting. To achieve multi-modal locomotion, conventional approaches often involve attaching multiple film-based actuators, each responsive to a specific stimulus, or stacking different films capable of responding to distinct types of stimuli. Accordingly, in this study, we developed an monolithic LCE film actuator that respond to both heat and light by incorporating a light-responsive azo-compound into the LCE film fabrication process. Based on this film, we studied the behavior of a multi-stimulus, multi-motion monolithic LCE film. Additionally, we explored LCE soft robotics in the form of filament shape. The flexibility of filaments in three-dimensional space allowed for the realization of complex locomotion that was previously unattainable with traditional film-type actuators. By introducing a helical structure into the LCE filament, we were able to achieve lateral-rolling locomotion. we further demonstrated the ability to program the rolling direction, enabling the filament to follow desired paths, from straight to curvilinear, by adjusting factors such as filament diameter, pitch, modulus, and environmental temperature. Based on this, we fabricated a self-adjusting, lateral-rolling LCE helical filament that can autonomously explore various terrains. This study showcased the diverse capabilities of this technology, including terrain exploration, maze navigation, target tracking, and overcoming obstacles such as staircases through adaptable rolling.