A Transparent Self-Healing Polyurethane-Isophorone-Diisocyanate Elastomer Based on Hydrogen-Bonding Interactions

Self-healing elastomers that can repair physical damage and extend their service life in medium- and low-temperature environments have attracted considerable attention in the field of flexible materials. However, the self-healing polyurethane (PU) healing process reported in previous studies regularly needs to be supported by high heating temperature and long healing time. In this study, a simple method was developed to synthesize a self-healing PU film using isophorone diisocyanate (IPDI) and a transparent rubber solution. The high transmittance (89%) of the resulting polyurethane-isophorone-diisocyanate (PUI) film was confirmed by UV-vis spectroscopy. FT-IR spectroscopy revealed that the hydrogen bonds formed by the imino group and the C═O bonds in IPDI and the transparent rubber facilitated the self-healing of the PUI composite film. The optical microscope observed that the self-healing PU can complete the self-healing of cracks in a short period. Moreover, a PUI film restored at 60 °C for 1 h withstood a load of 1 kg. Tensile tests showed that healing efficiencies of 82% and 99% were achieved by the PUI film healed at 60 °C for 1 and 2 h, respectively. A self-healing experiment conducted on a silver-nanowire/PUI-film system confirmed the synergistic recovery performance of PUI on a conductive coating. The self-healing PUI elastomers might have potential commercial prospects in transparent coatings, self-healing antibacterial films, robotic skins, and flexible electronics.