Electrochemical Deactivation of Switchable Catechol-Containing Smart Adhesive from Nonconductive Surfaces

The feasibility of deactivating and reactivating catechol-containing smart adhesive electrochemically while in direct contact with a nonconductive surface was explored in this work. The adhesive was coated over an aluminum mesh-attached polydimethylsiloxane (AM-PDMS) substrate. The aluminum mesh served as an electrode to apply electricity through the adhesive. A silver (Ag) counter electrode was coated in the periphery of the adhesive-substrate interface to deactivate the adhesive attached to the nonconductive surfaces including glass and poly(methl methacrylate) (PMMA) substrates. The deactivation of adhesive was performed with the application of up to 20 V of applied electricity utilizing the Ag electrode as a cathode and aluminum mesh as an anode. The adhesion strength of adhesive towards nonconductive surfaces decreased by 98% after in situ application of electricity. The deactivation rate was tunable with the applied voltage level, exposure time to applied voltage, surface area of the adhesive interface, and aluminum mesh size. The deactivated adhesive was reactivated electrochemically by reversing the electrode polarity up to 3 cycles utilizing catechol-boronate complexation chemistry.