Electrospun TPU/LCE Composite Fibers for High-Performance Biomimetic Tendon Actuation
Yongzheng Luo, Shen Gao, Mingjun Tang, Yue Wang, Tao Yue
AI summary
Problem
Traditional rigid actuators lack the safety, efficiency, and biomimetic motion of biological muscles, while existing liquid crystal elastomer (LCE) fibers remain too brittle and weak for practical tendon applications.
Approach
The researchers combined thermoplastic polyurethane (TPU) with LCE through an optimized electrospinning process, followed by mechanical stretching and UV curing, to create tough, uniaxially aligned fibers that act as artificial tendons.
Key results
- Stable electrospinning process for uniaxially aligned TPU-LCE composite fibers
- 44.4% thermal contraction strain with load capacity exceeding 3,500 times self-weight
- Durable cyclic operation over 120 thermal actuation cycles without degradation
- Integration into a 3D-printed biomimetic finger enabling smooth, human-like joint flexion-extension
Why it matters
Offers a scalable, bio-inspired material platform that overcomes the brittleness of pure LCEs, advancing the development of durable and biomimetic soft robotic systems.
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.