Geometrically insensitive deform-and-go liquid crystal elastomer actuators through controlled radical diffusion

Abstract

The geometric shape and programming of mesogen alignment are two critical prerequisites for the effective actuation of liquid crystal elastomer (LCE) actuators. However, existing alignment programming approaches inevitably impose limitations on the geometric design of LCEs. In this study, we introduce a controlled radical diffusion mechanism that enables geometrically insensitive programming of actuation. Our findings show that LCEs can be deformed into complex structures via soft-elasticity and achieve the required mesogen alignment by simply soaking the LCE in an aqueous solvent of a free-radical initiator. The process requires no external assistance (maintained force, fixture, heating, or light) and the omnidirectional radicals’ diffusion enables precise implementation of actuation across arbitrary geometries, including those produced through 3D printing, molding, embossing, and origami techniques. This “deform-and-go” strategy allows for scalable and versatile fabrication of advanced LCE actuators, representing a significant advancement in soft robotics engineering. Liquid crystal elastomers are used in actuators, though methods to pre-program actuation limits the geometric design. Here the authors show a method of treating the elastomers in free-radical initiator to program actuation.