Direct Observation of Double Layer Interactions between the Potential-controlled Gold Electrode Surfaces Using the Electrochemical Surface Forces Apparatus
We have designed a new apparatus, an electrochemical SFA, for measuring the forces between symmetric gold electrode surfaces under electrochemical potential control. The surface separation was determined by two-beam (twin-path) interferometry. The potential was applied to the gold surfaces (working electrode) in 1 mM aqueous KClO4 using Ag/AgCl as the reference and Pt as the counter electrode. We observed the van der Waals attraction and the double layer repulsion which decreased with the increasing potential from −0.1 to 0.2 V (vs. Ag/AgCl).