Stretchable Self-Healing Polymeric Networks with Recyclability and Dual Responsiveness

Intelligent polymers with tough networks are of considerable significance for the development of highly proficient polymer science and technology. In this work, polymeric elastomers with integrated stretchable and self-healable characteristics were designed by cross-linking hyperbranched polymers with flexible segments. The hyperbranched polymer with multiple terminal groups provided various cross-linking points so that mechanically robust networks could be achieved. Driven by the reversibility of imine and disulfide bonds employed, the elastomers exhibited good self-healing property, and the healing efficiency reached up to 99% under ambient environments. Furthermore, the dynamic reversibility of the polymers was investigated at the molecular level. The imine and disulfide bonds were incorporated into the networks to construct a soluble and recyclable hyperbranched polymer with pH and redox responsiveness via an A2 + B3 approach and Schiff base polymerization. The polymers containing imine bonds completed the polymerization-depolymerization transition and underwent reversible cycles several times through changing pH. Moreover, in the presence of disulfide bonds, the polymers were provided with a redox cleavage property triggered by dithiothreitol. This study provides new opportunities for the design and application of intelligent polymers with tough networks through regulation of topological structures.