Triple non-covalent dynamic interactions enabled a tough and rapid room temperature self-healing elastomer for next-generation soft antennas†
An elastomer with both mechanical robustness and self-healing capability is desired and is much needed to meet the increasing demand for next-generation soft electronics that can not only remotely sense and wirelessly communicate but also autonomically self-heal once damaged. It has long been a challenge for materials scientists and engineers to design and process such type of polymer since mechanical robustness and self-healing are largely contradictory in nature. Herein, elastomer networks based on synergetic triple dynamic non-covalent interactions are developed through a polyurethane–polyethylenimine (PU–PEI) colloidal complex. The PU–PEI elastomer exhibits a maximum tensile strength of 15.8 MPa, breaking elongation of 1360% and toughness of 127.8 MJ m−3, which are superior to those of the current suite of self-healable elastomers at room temperature. Meanwhile, the dynamic hydrogen bonds, ionic interactions and polymer entanglement interactions yield a self-healing efficiency of 86% in 3 hours in water at room temperature. The self-healing behavior can also autonomically occur in humid air. In addition to its superior mechanical properties, the PU–PEI elastomer is transparent, recyclable and solution processable. It was found that the PU–PEI colloidal complex could be doped with conductive fillers to form a printable composite ink so as to enable a self-healable 2.4 GHz Wi-Fi soft antenna, demonstrating the potential of the developed elastomer for application in integral soft electronics.