Hydrophobic Deep Eutectic Solvent Based Hydrophobic Polymer Adhesive with On-demand Detachability, Strong Broad-Spectrum Adhesion in Air/Aquatic Environments

Abstract

The significant advancement in wet/underwater adhesives presents considerable challenges concerning longevity, reusability, and universality in achieving adhesion, features that are seldom addressed by existing adhesives. Herein, a new design strategy, rarely reported previously, is proposed to prepare hydrophobic polymer adhesives via one-step copolymerization of hydrophobic monomers in hydrophobic deep eutectic solvents. The abundant noncovalent interactions and the hydrophobic structure within adhesive system collectively endow the adhesive 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 exhibits excellent environmental tolerance and maintains strong adhesion performance for up to 10 days in air, pure water, seawater, strong acid and alkali mediums. Furthermore, the temperature-dependent viscoelastic behavior results in a precipitous drop of adhesive strength once the temperature exceeds 50 °C or falls below -20 °C. Controlling temperature or utilizing hot ethyl acetate solvent can both achieve 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.