Ultra‐Strong and Conductive Bio‐Based Polyurethane Urea Eutectic Gel for On‐Skin Sensing and Health Monitoring

ABSTRACT Flexible electronic skin (E‐skin) represents a core component of wearable health monitoring systems, offering substantial potential in intelligent healthcare applications. However, the development of E‐skin materials that integrate high mechanical strength, excellent conductivity, and sustainability remains a formidable challenge. Herein, inspired by human skin, we develop a high‐strength and highly conductive bio‐based polyurethane urea eutectic gel (BPUU‐E), fabricated by incorporating bio‐based polyurethane urea (BPUU) into a zinc chloride/ethylene glycol (ZnCl 2 /EG)‐based metal salt deep eutectic solvent (MDES). Leveraging the “trident” coordination sites within BPUU molecular chains, a dual dynamic crosslinking network of “multiple hydrogen bonds—metal coordination bonds” is constructed, endowing the material with excellent mechanical properties (fracture strength up to 83.2 MPa, fracture toughness of 556.6 MJ m −3 ) and ionic conductivity (43.6 mS m −1 ). The flexible strain sensor based on BPUU‐E can stably monitor human joint movements and dynamic injury repair. Furthermore, integrating a sensing array and combining the Internet of Things and machine learning, enables high‐precision recognition of gait patterns. This study presents an innovative strategy for developing flexible E‐skin that possesses high strength, high conductivity, sustainability, and has significant application prospects in the field of intelligent wearable healthcare.