A Biologically Muscle-Inspired Polyurethane with Super-Tough, Thermal Reparable and Self-Healing Capabilities for Stretchable Electronics

Polymeric elastomers play an increasingly important role in the development of stretchable electronics. A highly demanded elastic matrix is preferred to own not only excellent mechanical properties, but also additional features like high toughness and fast self-healing. Here, a polyurethane (DA-PU) is synthesized with donor and acceptor groups alternately distributed along the main chain to achieve both intra-chain and inter-chain donor-acceptor self-assembly, which endow the polyurethane with toughness, self-healing, and, more interestingly, thermal repair, like human muscle. In detail, DA-PU exhibits an amazing mechanical performance with elongation at break of 1900% and toughness of 175.9 MJ m(-3). Moreover, it shows remarkable anti-fatigue and anti-stress relaxation properties as manifested by cyclic tensile and stress relaxation tests, respectively. Even in case of large strain deformation or long-time stretch, it can almost completely restore to original length by thermal repair at 60 degrees C in 60 s. The self-healing speed of DA-PU is gradually enhanced with the increasing temperature, and can be 1.0-6.15 mu m min(-1) from 60 to 80 degrees C. At last, a stretchable and self-healable capacitive sensor is constructed and evaluated to prove that DA-PU matrix can ensure the stability of electronics even after critical deformation and cut off.