Soft, self-sensing, and programmable actuators are of great interest to applications ranging from robotics to adaptive structures. Liquid crystal elastomers (LCEs) are promising actuator materials due to their large reversible, anisotropic, and contractile strain with high energy density in response to heat stimulus. Recently, we have demonstrated LCE inks and an extrusion based alignment method to align liquid crystal mesogens (i.e., direction of contraction) to a 3D printing path, where alignment depends on processing conditions and ink rheology. Here, we present a method of fabricating innervated LCEs (iLCEs) with core-shell 3D printing, where composite filaments are comprised of a LCE shell and coaxial liquid metal core. iLCEs are Joule heated through the core with programmable and predictable heat generation and strain. Importantly, iLCEs self-sense their own deformation during actuation, as strain closely correlates with resistance in both unidirectional and 3D morphing structures. Additionally, their large concomitant changes in length and resistance and their high energy density enables closed loop control of iLCE fibers and spiral architectures, with actuation sequence regulation even with large bias loads. Our platform enables multimaterial 3D programming of soft actuation with embedded liquid metal features for seamless integration into complex, 3D printed robotic matter and adaptive shape-morphing structures.

Innervated, self-sensing liquid crystal elastomer actuators with closed loop control

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.