Synthesis and Characterization of Flexible Hydrogel Electrodes for Electrochemical Impedance Measurements of Protective Coatings on Metal Sculptures

A novel conductive anionic hydrogel was synthesized for use as a solid electrolyte for electrochemical impedance spectroscopy (EIS) characterization of the barrier properties of protective coatings on outdoor metalworks, such as bronze sculptures. The AMPS-co-PAA hydrogel was soaked in a variety of aqueous salt solutions and characterized by swelling capacity and conductivity in order to determine the most appropriate gel/liquid electrolyte combination for use on culturally significant objects. K2PIPES-equilibrated hydrogels were selected as the preferred electrodes for this particular application and were used to measure the impedance of a coated substrate, yielding spectra similar to those from standard liquid cells.