Hollow liquid crystal elastomer fiber used as versatile platform towards functional composites

The design and engineering of liquid crystal elastomers (LCE) composites for enhanced multifunctionality and responsiveness is highly desired. Here, a hollow LCE (h-LCE) fiber fabricated via coaxial spinning, enabling the straightforward yet effective creation of functional LCE composites, is reported. Inspired by the sophisticated fiber-tubule architecture in mammalian skeletal muscles, the hollow fiber features an LCE outer shell for programmable actuation and an inner channel allowing for the integration of a variety of functional media. Thus, the h-LCE fiber can serve as a versatile platform for multifunctionalities in LCE composites. With this unique design strategy, we fabricate h-LCE fibers with lengths exceeding 3 meters in the lab with outer diameters and inner diameters as small as 250 µm and 120 µm, respectively. We further demonstrate the versatility of these h-LCE fibers across various applications, from fast-response stiffness-tunable actuators by integrating water flow as the triggering media and shape memory polymer (SMP) for enhanced mechanical properties, to electrically driven actuating systems through the incorporation of liquid metal, and actuating light-guides