Construction of self-healing disulfide-linked silicone elastomers by thiol oxidation coupling reaction

Abstract

Developing self-healing silicone elastomers are highly significant because of their promising applications. Herein, we present novel self-healing disulfide-linked silicone elastomers (SEs) based on thiol-terminated sulfur-containing heterochain polysiloxanes (P-SHs) and three thiolcontaining crosslinkers, including pentaerythritol tetrakis(β-mercaptopropionate) (PETMP), octa (3-mercaptopropyl)silsesquioxane (POSS-SH), and poly[(mercaptopropyl)methylsiloxane] (PMMS), via the thiol oxidation coupling reactions. The construction of these SEs can rapidly proceed at room temperature. The effects of crosslinker species and amounts on the formability and mechanical properties were investigated. The silicone elastomers can be self-healed by heating at 150◦C for 2 h or under UV radiation for 30 min after cutting them into pieces and the self-healing efficiency is >70%. Moreover, they can be utilized as adhesives for bonding glass sheets, which can hold a 200 g weight. The bonding is reversible and can repeatedly proceed many times, indicating that these materials can promisingly be applied as reversible adhesives. These results indicate that a thiol oxidation coupling reaction is a simple and effective strategy for the construction of self-healing disulfide-linked elastomers. Under this strategy, more disulfide-linked organic elastomers with self-healing properties can be designed and constructed and their applications can be further explored.