Electrospun TPU/LCE Composite Fibers for High-Performance Biomimetic Tendon Actuation

Abstract

Traditional rigid actuators in soft robotics, particularly for bionic hands, suffer from structural complexity, bulkiness, and limited biomimetic motion. To address these limitations, we developed an electrospun composite fiber membrane composed of thermoplastic polyurethane (TPU) and liquid crystal elastomer (LCE), and demonstrated its feasibility as a tendon-like soft actuator in an artificial finger. TPU provides elasticity and mechanical robustness, while LCE contributes reversible thermal contraction as the actuation unit. The resulting TPU-LCE fibers exhibit high flexibility comparable to biological muscle and outstanding actuation performance. Under thermal stimulation, the actuator achieved a contraction strain of up to 44.4% and a load-bearing capacity exceeding 3,500 times its own weight, while maintaining durability over 120 actuation cycles without significant degradation. Integrated into a tendon-driven biomimetic finger, the actuator enabled smooth and natural joint motions, closely resembling human finger flexion–extension gestures. This work presents a reliable and scalable bio-inspired actuation strategy, offering promising potential for soft robotics applications.