Liquid crystal elastomers (LCEs) possess intrinsic anisotropy, capable of undergoing reversible large deformations or pronounced color changes in response to external stimuli. When fabricated into one-dimensional LCE fibers, their structural characteristics of high aspect ratio and large specific surface area further confer special advantages, exhibiting flexible constructability and excellent response properties in applications such as actuators, artificial muscles, soft robots, and mechanochromic sensors. In recent years, with the advancement of advanced manufacturing technologies, significant progress has been made in the preparation and performance studies of LCE fibers.

The research group led by Zhongqiang Yang from the Department of Chemistry, Tsinghua University conducted a systematic review of LCE fibers to gain a deeper understanding of their development history and potential applications. Firstly, they introduced the development history and research significance of LCE fibers. Secondly, they explained the stimulus-response principle of LCE fibers. Based on the arrangement of liquid crystalline units, LCE fibers are classified into axially oriented LCE fibers and cholesteric LCE fibers. The former typically undergo reversible large deformations in response to external stimuli, including thermally based stimuli (heat, light, electricity) and non-thermal stimuli (pneumatic pressure); the latter exhibit obvious color changes under external stimuli, with mechanical force stimulation being widely studied. Subsequently, the review focused on the preparation methods of LCE fibers, including melt spinning, dry spinning, wet spinning, electrospinning, and template methods. They analyzed the structure, responsiveness, and deformation characteristics of the obtained LCE fibers and elaborated on the advantages and disadvantages of each preparation method in detail. Following this, they summarized the research and application progress of LCE fibers in the fields of actuators, artificial muscles, soft robots, and mechanochromic sensors, revealing their important status and role as emerging smart materials. Finally, they discussed the limitations and challenges faced during the development of LCE fibers and outlined future research directions in this field. Specifically, these include improving actuation response speed, optimizing actuation mechanical properties, exploring novel actuation modes, enhancing multifunctionality, and promoting interdisciplinary research.

Figure 1. Schematic of the fabrication methods, type of stimuli, and applications for LCE fibers

Figure 2. Stimulus-response mechanisms of LCE fibers