Fig. 2
a Interaction profiles Fn(D)/R between gold and bare mica surfaces across 2 mM NaNO3, at a given contact point, under different applied potentials Ψapp. Gold surface potential Ψgold values in legend are extracted from respective fits (black curves) to the PB equation with constant charge (mica) vs. constant potential (gold) boundary conditions, augmented by vdW attraction44,45. b An example for dynamic measurements (D(t) plots) taken at different surface separations, in response to positive and negative step potential between – 0.2 V and + 0.2 V. The peaks indicate the transient movement of the lower surface (mica) in response to application of the step potential changes. Measurements both of the interaction profiles (a) and the response to potential changes were performed between the same surfaces and salt solution (2 mM NaNO3). c A magnified view of transient peaks (circled in the D(t) plots in b) obtained at different gold-mica separations, where Di and Df are the initial and extremal surface separation values, respectively. Scale bars: horizontal – 0.2 s; vertical – 5 nm
