Ultrahigh tough, self-healing copolymer elastomer crosslinked by reversible imine system

Abstract

Improvement of toughness is still a challenge for self-healing materials. Most of self-healing materials difficultly balance the mechanical and self-healing property. Here, a molecular design strategy of copolymer is proposed based on three combinations of reversible imine bond, chain motion and thermosensitive hydrogen bond together. The approach initially forms a co-continuous microphase separation structure and then cross-linked by aromatic imine via esterification reaction and Schiff base reaction, which features efficient self-healing, ultrahigh strength and toughness. The resultant elastomer exhibits a high stress at break (≈3 MPa) and high fracture strain (≈600 %). Additionally, the elastomer can reach 95 % self-healing efficiency after healing at 100 °C for 12 h. Extra reversible imine crosslinking displays a doubly promotion for fracture stress, and unchanging strain as well as 1times increase for self-healing efficiency, compared with merely chain motion and hydrogen bonding. This elastomer can be successfully spun into stretchable, conductive, self-healing filaments with core-shell structure by wet spinning and coating methods. It shows excellent corrosion resistance against NaCl, and conductive and self-healing property after coating by PANI polymer. This new type of self-healing polymer is promising to expand the application in future tissue engineering, soft robotics, and biomedical devices.