Tunable, reusable, and recyclable perfluoropolyether periodic dynamic polymers with high underwater adhesion strength

Abstract

•Molecular design of hydrophobic, nanophase-separated morphologies •Understanding the influence of bulk dynamics on adhesive strength •Demonstration of a high-strength recyclable underwater adhesive Most adhesives lose adhesion in the presence of water. Here, hydrophobic perfluoropolyether (PFPE) dynamic polymers with periodically embedded hydrogen bonding units operate as effective underwater adhesives by enhancing van der Waals interactions and minimizing bulk water uptake. Optimizing the bonding interactions in the polymers and their bulk dynamics enables high cohesive strength while maintaining a hydrophobic, nanophase-separated morphology to prevent water-based failure mechanisms. The resulting adhesives have high adhesion strength and can be reversibly applied in fully underwater conditions to polyimide, glass, and steel substrates without any solvent or covalent crosslinking, at room temperature, and without substrate modifications. Moreover, the polymer adhesive can be readily recycled due to the use of dynamic crosslinking to achieve adhesion. This work shows how dynamic PFPE polymers with tunable structures and properties can be designed for high-strength recyclable underwater adhesives, which could enable reversibly attachable and detachable waterproof wearable devices. Most adhesives lose adhesion in the presence of water. Here, hydrophobic perfluoropolyether (PFPE) dynamic polymers with periodically embedded hydrogen bonding units operate as effective underwater adhesives by enhancing van der Waals interactions and minimizing bulk water uptake. Optimizing the bonding interactions in the polymers and their bulk dynamics enables high cohesive strength while maintaining a hydrophobic, nanophase-separated morphology to prevent water-based failure mechanisms. The resulting adhesives have high adhesion strength and can be reversibly applied in fully underwater conditions to polyimide, glass, and steel substrates without any solvent or covalent crosslinking, at room temperature, and without substrate modifications. Moreover, the polymer adhesive can be readily recycled due to the use of dynamic crosslinking to achieve adhesion. This work shows how dynamic PFPE polymers with tunable structures and properties can be designed for high-strength recyclable underwater adhesives, which could enable reversibly attachable and detachable waterproof wearable devices.