A tough polyurethane elastomer with self-healing ability

Due to sufficient polymer chain mobility and molecular diffusion, most of the present intrinsic self-healing polymers that heal damage by utilizing reversible bonds are soft or gel. However, a tough self-healing polymer is needed as they can be used as strong and light weight material for engineering applications . Based on the high versitility of polyurethanes , herein we report the development of a disulfide-containing poly(urea-urethane) (PUU) network, where aromatic disulfide diamine is used to establish linkages for tri-functional homopolymer of hexamethylene diisocyanates (tri-HDI) as well as aliphatic prepolymer chains, resulting in the readily conversion between a well cross-linked network and an un-crosslinked structure. With this linkage, the network is able to balance the two seemly contradictory forces, exhibiting simultaneously superior mechanical performances and high self-healing efficiencies in the absence of any catalyst or external intervention. In addition, these materials are capable of repairing themselves repeatedly thus possessing a high potential for industrial applications with further investigation.