Light-modulated liquid crystal elastomer actuator with multimodal shape morphing and multifunction

Abstract

Stimulus-responsive materials provide an attractive platform to design and build distinguished soft robots that can dynamically change their shapes to adapt for a variety of functions. However, in most cases, soft robots mainly rely on delicately and laboriously tailoring material composition and molecular orientations to achieve desirable shape morphing. Moreover, the integration of multimodal shape morphing into a single robot, control of the evolution between different morphing modes, complex locomotion, and facile fabrication represent major challenges in this area. Here, we show a facile strategy to photomanipulate shape morphing of a soft millirobot made of an NIR-active liquid crystal elastomer by programming the direction and magnitude of strain gradient in the LCE by using the spatial and localized features of light stimuli. This photomanipulation strategy not only enables the millirobot to generate a wide range of morphing modes, but also allows local and reversible evolution between different morphing modes in a single soft robot. With these phototunable morphing capabilities, the millirobot is able to exert multimodal locomotive behaviors, including crawling, shifting, rotating, somersaulting, rolling, and even fast autonomous rocking driven by a self-oscillatory motion. In addition, the highly mobile millirobots show the multifunctions of not only navigating with controllable directions but also escaping out from heavy weight and even swimming through a small pipe. It is anticipated that this photoactive and reconfigurable material system would open exciting possibilities to develop intelligent soft robots with seamless integration of multimodal shape morphing and multifunctions.