Photo actuation performances of animal hair fiber-reinforced polysiloxane liquid crystalline elastomer composites

Liquid crystalline elastomers (LCEs) are an emerging class of smart materials for soft actuation machines. LCE composites (LCECs), via the incorporation of fillers into LCE matrices, bring superior functionalities to overcome the modest robustness and mechanical actuation performance. Considering the distinctive structures, good physico-chemical and mechanical properties of some animal fibers, we propose a cost-effective design and fabrication of LCECs by dispersing cat hair fibers into a polysiloxane LCE matrix, forming a cat hair fiber reinforced polysiloxane main-chain LCEC. The cat hair fibers demonstrate good integration and compatibility properties with the matrix, and construct a reinforcement network, which can enhance the mechanical actuation properties while adapting to the large reversible deformable capability of LCE matrix due to its high flexibility. By doping the LCE matrix with a small amount of graphene, the LCECs demonstrate strong photothermal actuation performances. The modulus, tensile strength, and output driving force activated by light stimulus are remarkably enhanced. LCECs also demonstrate greatly increased resisting fatigue failure reliability under high loadings and repetitive cycles of photo actuation. The liquid crystal phase structure, mesomorphic properties, phase transition temperature and deformation ratio of LCE matrix do not change or weaken. Our LCEC design and fabrication provide a promising way for LCE application potential, and can be extended to other animal fiber incorporated LCECs, bringing more rich actuation capabilities needed by soft actuators and beyond.