Self-Healing and\nRecyclable Fabric Coatings Based\non Boroxine–Polyurethane

Fabric coatings, offering a range of benefits to personal\nhealth\nand the environment and addressing other specific needs, present a\npromising application in various fields. However, ensuring their long-term\nreliability, durability, and recyclability remains crucial to meet\nthe demands of practical applications and sustainable development.\nTo address this problem, we have developed a self-healing polyurethane\n(BPU) that integrates phenylboronic acid groups into the polyurethane\nchains and cross-links them to form dynamic boroxine bonds. This unique\nstructure endows the BPU with a healing efficiency of 94%, a recycling\nefficiency of 93%, and an adhesion strength to cotton fabric of 1.42\nMPa due to the high mobility of polymer chains and dynamic boroxine\nbonds. Leveraging these exceptional properties, we successfully prepared\na multifunctional coating fabric (BPU/APD) by incorporating an azobenzene–polyurethane\npolymeric dye (APD) with BPU as a binder. This BPU/APD-coated fabric\nshows reversible photoisomeric behavior, remarkable ultraviolet protection\nfunction (UPF = 85.8), and excellent durability against washing and\nadhesion. Notably, the coated fabric can fully heal tiny scratches\nat 60 °C under 3 MPa for 5 min. After undergoing four healing\ncycles, the fractured coating fabric retains over 85% of its initial\nstrength following the first healing, indicating its multiple healing\ncapabilities. Moreover, the BPU/APD coatings on the waste fabrics\ncan be recycled and reused repeatedly, maintaining a similar color\nstrength and adhesion strength. This research paves the way for the\ndevelopment of multifunctional coating fabrics through the creation\nof self-healing polyurethane coatings, proving its great potential\nin smart textiles.