Fabrication and characterization of a fully screen-printed Ag/AgCl reference electrode using silica gel inks exhibiting instantaneous usability and long-term stability

Abstract

An instantly usable screen-printed Ag/AgCl electrode with long-term stability was fabricated for use as a cost-effective disposable reference electrode. A new silica gel–poly(vinylidene difluoride) ink was prepared to form the hydrophilic liquid junction and electrolyte layer of a planar-type reference electrode and the temporal evolution of its open-circuit potential in different electrolyte solutions was subsequently compared to that of a commercial reference electrode. The potential stabilized within 3 min and remained constant over 20 days. The impedance of the liquid junction was ~2500 Ω, which is close to the value observed for a commercial reference electrode. These results implied that the as-fabricated reference electrode was well-suited for practical measurements.