Mussel-Inspired Green Cross-Linking of Silicone Elastomers and Its Tunable Adhesion Behavior and Underwater Curing Capability

Silicone elastomers have been widely used in underwater environments as significant sealants and adhesives. However, silicone elastomers usually need to be cured in air because excess water can inhibit or prevent their curing process. In this study, inspired by mussels, we have prepared catalyst-free and eco-friendly silicone elastomers using catechol as a green cross-linker. Under mild conditions (pH 8.5), catechol- and amino-functionalized polysiloxanes are cross-linked to form elastomers by Michael addition and Schiff base reactions. As an adhesive, it shows excellent adhesion to different materials. The lap shear strength with the aluminum substrate is 2.1 times higher than that of conventional silicone rubber, reaching 0.62 MPa, and the adhesive tensile strength can reach 0.72 MPa. Notably, it can significantly accelerate the curing of elastomers in the presence of a hydrogen peroxide solution, which results in very fast curing underwater. Moreover, the as-prepared silicone elastomers can effectively plug leaks and exhibit excellent adhesion properties in water. Developing bioinspired silicone elastomers that can be cured underwater may shed light on the research of eco-friendly silicone materials and offer innovative insight for mussel-inspired adhesives.