High-Strength, Recyclable, Self-Healing Polyurethane Elastomers with Mechanically Responsive Self-Reinforcement

Abstract

Self-healing materials have significant potential in applications such as electronic skin and soft robotics. However, integrating self-healing properties with mechanical properties remains a major challenge, which limits their applications. In this study, we introduce a polyurethane (PU) elastomer based on strain-induced crystallization (SIC), which exhibits high tensile strength (21.5 MPa), toughness (157.6 MJ m–3), and fracture energy (83.1 kJ m–2), along with a self-healing efficiency of up to 98% under mild conditions (60 °C). These extraordinary mechanical performances arise primarily from the carefully engineered structural design of the molecular chains and the optimized ratio of soft segments. During large deformations, the dynamic disulfide and hydrogen bonds within the elastomer effectively dissipate stress energy while preserving the SIC crystalline structure formed by the soft chains, which serve as physical cross-linking points and reinforcing phases. Additionally, the loosely packed hard domain structure and dynamic bonding interactions enable the elastomer to maintain excellent self-healing properties. This SIC-based elastomer can be used to fabricate flexible electronic sensors for stable and accurate detection of human motion signals.