Self-Healable Silicone Elastomer Based on the Synergistic Effect of the Coordination and Ionic Bonds

The construction of silicone elastomers with mechanical strength and a self-healing property can be verified as an effective method by multiple dynamic bond strategies. However, it means that some complex synthesis strategies or small molecules with specific chemical structures are required. So, it is more challenging to construct a kind of polymer matrix with two kinds of interactions by matured methods directly. Herein, we report a dynamic silicone elastomer with two kinds of interactions that was prepared by incorporating a "carboxyl-amino ionic bond" and "carboxyl-Al3+ coordinated ionic bond". The carboxyl groups are bonded with amino groups and Al3+ ions to form common ionic bonds and coordinated ionic bonds, respectively. The coexistence of these strong and weak ionic synergistic interactions was verified by setting several experiments in spectroscopic analysis and mechanical tests. It was indicated that the carboxyl-Al3+ interactions can improve the mechanical property of this material effectively, while the dense common ionic network between carboxyl and amino groups can maintain the integrity of the dynamic cross-linking network, which may ensure the good recoverability and self-healable ability of the silicone elastomer. Compared with the control samples based on single ionic bonds, the hybrid network exhibited the better mechanical property with an optimistic tensile strength of ∼0.73 MPa and elongation at breaking of ∼548%, and the network also exhibited a good autonomous self-healing ability at a higher temperature (8 h, 80–136% at 60 °C) and a considerable recoverability at a large scale of stretching (∼70% of elongation at break) with a moderate low hysteresis ratio of only 28.7%. We expect this strategy would be beneficial for the expansion of a convenient way of mixing to prepare elastomers with a synchronous mechanical property and self-healing performance by multiple dynamic bond strategies.