Salicylhydroxamic Acid as a Novel Switchable Adhesive Molecule

The feasibility of salicylhydroxamic acid (SHAM) to functionasa pH-responsive, switchable adhesive molecule is explored here. Usinga custom-built Johnson-Kendall-Roberts contact mechanicstest setup, SHAM-containing adhesive demonstrated strong, wet adhesionto various surfaces (glass, titanium, polystyrene and amine-functionalizedglass) at pH 5 with adhesive properties that were comparable to thoseof catechol. The work of adhesion of SHAM decreased by nearly 98%with increasing pH and fully recovered when treated with pH 5. Mostimpressively, SHAM recovered its adhesive property even after itsexposure to pH as high as 11, indicating superior stability towardbase treatment. This result contrasts the case of catechol, whichdid not recover its initial adhesive property due to irreversibleoxidation. Finally, density functional theory calculations were usedto confirm that the observed tunable adhesion property was due tothe deprotonation of SHAM.

Automated summary

The feasibility of salicylhydroxamic acid (SHAM) as a pH-responsive, switchable adhesive molecule was explored. SHAM-containing adhesive demonstrated strong, wet adhesion to various surfaces at pH 5, comparable to catechol. The adhesive properties of SHAM decreased with increasing pH but fully recovered at pH 5, indicating superior stability towards base treatment.