Self-healing waterborne polyurethane elastomers based on synergistic hydrogen, disulfide and borate bonding for composite conductors

As a functional material, polyurethane elastomers have found different applications in a variety of fields such as flexible electronics and smart coatings, but due to the damage during use, they are often endowed with self-healing properties. However, conventional intrinsically self-healing polyurethanes often don't balance excellent mechanical and self-healing properties, so it has become crucial to prepare polyurethane elastomers with excellent self-healing properties and high mechanical properties. In this study, a self-healing waterborne polyurethane elastomers (IP-DTDAx-BAy-WPU-n) was synthesized based on 4, 4-diaminodiphenyl sulfide (DTDA) boronic acid (BA). The disulfide bond has high motility at low temperatures and induces molecular-level healing at the damaged interface, contributing to good repair under mild conditions. The borate ester bond limits intermolecular chain slippage and improves the mechanical properties as a dynamic cross-linking point, while its dynamic reversible effect can synergistically improve the self-healing ability. The results show that the synthesized elastomer films have good mechanical properties (strength 23.21 MPa, elongation at break 1259.08%, toughness 83.28 MJ m −3 ), good elastic recovery and self-healing properties (93%). Furthermore, a composite conductors (IP-DTDAx-BAy-WPU/AgNWs) with self-healing properties was prepared by compositing AgNWs nanowires with polyurethane elastomers, which laid the foundation for its application in flexible electronic devices and wearable sensing devices. Graphical