Self-Healing Thermoplastic Elastomers Enabled by Dynamic Ordered Microphase Crosslinking of Random Copolymers

Abstract

Self-healing thermoplastic elastomers based on reversible supramolecular or covalent bonding often suffer from low mechanical strength to compensate their molecular mobility in ensuring effective end-to-end contact during repair. Herein, we propose a new strategy for self-healing elastomers using dynamic ordered microphase as the self-healing motif. A series of polyacrylonitrile-co-poly(n-butyl acrylate) copolymer elastomers are prepared by simple free radical polymerization. These elastomers, within a certain range of comonomer ratios, exhibit remarkable self-healing capabilities in bulk form. The ever-maintained strength of the repaired elastomer is attributed to the retention of intrinsic material strength by the dynamic ordered phase, rather than relying on reversible bonding typical of traditional self-healing materials. As a result, these elastomers deliver exceptional stretchability, mechanical strength of 7.45 MPa (vs. original 7.25 MPa), and toughness of up to 14.9 MJ m^-3, in addition to complete healing within 3 h. The designed elastomers integrate rapid healing, high repaired strength and toughness, feasible preparation, and recyclability. The rather facile synthesis of these self-healing elastomers can be generalized to other deformable strength-required and fast healing-needed materials at low cost, showing great application potentials in new energy and wearable electronics.