Hofmeister‐Effect‐Driven Hybrid Glycerogels for Perfect Wide‐Temperature Shape Fixity and Shape Recovery in Soft Robotics Applications

Abstract

Shape memory gels have emerged as crucial elements in soft robotics, actuators, and biomedical devices; however, several problems persist, like the trade‐off between shape fixity and shape recovery, and the limited temperature range for their application. This article introduces a new class of shape memory hybrid glycerogels (GGs) designed to address these limitations. The well‐modulated internal structure of the GGs, facilitated by the Hofmeister salting‐out effect, strategically incorporates a higher crystallite content, abundant crosslinking points, and a high elastic modulus. Unlike reported shape memory gels, the GG exhibits a perfect triple‐step shape memory behavior in air with 100% shape fixity in a wide programming temperature range (75–135 °C) and simultaneously achieves 100% shape recoverability. The gel recovers its shape at −40 °C under near‐infrared light across a wide programming temperature range (25–135 °C), showing unexpected initiation even at subzero temperatures. Inspired by the mechanics of composite structures, a method is proposed to integrate the GG seamlessly with a shape memory alloy, which further expands the temperature range that yields perfect shape memory properties. Finally, two light‐controlled fluttering and crawling soft robot prototypes are engineered to illustrate the versatility and potential applications of the composite gel in soft robotics.