Hydrophobic deep eutectic solvent-based hydrophobic polymer adhesive with on-demand detachability and strong broad-spectrum adhesion in air/aquatic environments

Abstract

The significant advancements in wet/underwater adhesives present considerable challenges concerning the longevity, reusability, and universality of adhesives, which are the features that are seldom adhered by existing adhesives. Herein, a new design strategy is proposed to prepare hydrophobic polymer adhesives via a one-step copolymerization of hydrophobic monomers in hydrophobic deep eutectic solvents. The abundant noncovalent interactions and the hydrophobic structure within the adhesive system collectively endowed the adhesive with broad-spectrum adhesion capacity to various hydrophobic and hydrophilic solid surfaces. Intriguingly, the lap-shear adhesion strength reached up to 2.5 MPa on representative hydrophilic steel and 467 kPa on challengeable hydrophobic polytetrafluoroethylene with smooth surface and low surface energy. Additionally, the adhesive exhibited excellent environmental tolerance and maintained strong adhesion performance for up to 10 days in air, pure water, seawater, and strong acid and alkali mediums. Furthermore, the temperature-dependent viscoelastic behavior resulted in a precipitous decrease in the adhesive strength when the temperature exceeded 50 °C or dropped below −20 °C. Controlling the temperature or using a hot ethyl acetate solvent achieved rapid, on-demand detachability of the adhesive. This study offers a novel strategy for the development of hydrophobic adhesives to address specific requirements in practical applications.