Bioinspired Photonic Polyurethane: Uniting Self-Healing and Flexibility for Multiple Sensing
Flexible photonic crystal (PC) materials exhibit exceptional optical properties but suffer structural degradation under repeated mechanical stress, leading to photonic band gap impairment and limited sustainability. This study introduces a self-healing thermoplastic polyurethane (STPU) with an inverse-opal PC structure, inspired by natural structural coloration and self-healing mechanisms. Synergistic dynamic covalent disulfide bonds and hydrogen bonds enable reversible mechanical adjustment, yielding a tensile strength of 26.76 MPa and elongation at break of 2000%. The inverse opal structure facilitates reversible color transitions in response to solvents (water, ethanol) and mechanical strain (0–70%) via lattice spacing modulation. Incorporating an interpenetrating network of polyacrylamide hydrogel and carbon nanotubes enhances strain sensitivity and structural color stability. The material demonstrates broad potential in flexible sensors, adaptive optical devices, bioinspired robotic skins, and dynamic anti-counterfeiting encryption, overcoming traditional PC limitations such as high fragility and single functionality. This strategy advances durable intelligent sensing materials with enhanced environmental adaptability and multifunctional integration.