A highly-stable multi-responsive bimorph liquid crystal actuator with chemically soldered heterogenous interface

Abstract

<p>Stimuli-responsive liquid crystal (LC) actuators are in high demand in bioinspired robotics and tissue engineering. However, multiple stimuli-responsiveness with low actuation threshold and high long-term stability is still suspected, because it remains challenging to seamlessly integrate multifunctional elements into LC polymer matrix while maintaining ordered mesogenic alignments. Here, we demonstrate a metal coordination-assisted interfacial polymerization strengthening strategy for the fabrication of a stable and multi-responsive LC actuator with an integrated bilayer architecture through a surface modification combining with two-stage polymerization. Thanks to high heat conduction of the tightly-combined heterogeneous interface and notable photo- and electro-thermal performances of silver nanowires, the resulting actuator can achieve fast light-driven upward arching shape-morphing to 181<sup>o</sup> in 2.4 s at a low near-infrared intensity of 0.9 W cm<sup>-2</sup> and strong voltage-tolerant rolled deformation at a bending angle of 400<sup>o</sup> over <styled-content style-type="number">1000</styled-content> cycles at 2.2 V. With the copolymerization of hydrophilic chains in LC matrix, the hydrophilic disturbance-triggered anisotropic expansion drives a humidity-responsive actuation. As a top-performing actuator among the previously reported multi-stimuli responsive actuators, diverse smart robots of photo-actuated crawler, electric-powered gripper and electro-humidity driven oscillator are realized. This work promises an opportunity for intelligent soft robotics.</p>