Thermal and Mechanical Activation of Dynamically Stable Ionic Interaction toward Self-Healing Strengthening Elastomers

Abstract Biological tissues can grow stronger after mechanical damage and self-healing. However, artificial self-healing materials usually show decreased mechanical properties after repairing mechanical damage. Here, a self-healing strengthening elastomer (SSE) is developed by engineering kinetic stability in elastomeric ionomers through introduction of large steric hindrance. Elastomeric ionomers are usually thermodynamically instable due to the none-directionality and none-saturation of electrostatic interaction and the high mobility of molecular chains; thus, their mechanical properties change with time in an uncontrollable manner. However, the large steric hindrance on the cationic groups prevents the formation of new ionic bonds and rearrangement of ionic aggregates under room temperature, thus SSE is kinetically stable. Once heat or external force is applied, the kinetic stability is disrupted and the material becomes stronger driven by the thermodynamic instability. Consequently, the self-healing efficiency of fractured SSE is as high as 143%. This work provides controllable and universal strategy to fabricate biomimetic self-healing strengthening materials.