Multiple dynamic bonds enable high mechanical strength and efficient room-temperature self-healable polyurethane for triboelectric nanogenerators

For room temperature self-healing triboelectric nanogenerators (TENGs), the inherent contradiction between mechanical strength and self-healing properties was an urgent problem to be solved. Based on the phenol-carbamate bond, this paper proposed a strategy to design a new molecular structure and coordinate the triple dynamic bonds, which provided a feasible strategy to solve this contradiction. With polytetramethylene ether glycol (Mn = 1,000) as the soft segment in the main chain of polyurethane (PU), meanwhile methylene diphenyl diisocyanate and 4,4 '-dihydroxybiphenyl (BP) as the hard segment and chain extension agent, respectively, the combination of tetrad benzene ring endowed the resultant 4BP-PU with pi-pi interaction. The effective reversible dissociation and association with hydrogen bond not only bestowed 4BP-PU with high mechanical strength (16.14 MPa), but also promoted high self-healing efficiency (94.8%) at room temperature. 4BP-PU was selected as the elastic substrate between polydimethylsiloxane and copper sheet to prepare a self-healing TENG to collect energy from natural motion. Consequently, the rational molecular structure design provided new ideas for developing self-healing materials and fabricating energy harvest electronics.