Overall, more homogeneous NPG films are formed from Au oxides prepared by HV electrolysis at 300 V compared to 540 V. Exfoliation of the Au oxide only occurs after 30 s electrolysis time at 300 V, where the Au oxide is thicker than that formed at 540 V, but is also less homogeneous. This suggests that thick Au oxide films might not adhere as well to the substrate as thin Au oxide films. Whether the Au oxide film exfoliates during the HV electrolysis or the emersion of the electrode from the electrolysis solution can not be deduced from our experiment. Why the structural properties of the Au substrate in the regions where the NPG film exfoliated are different for the preparation procedures at both voltages is currently unclear. Finally, the question remains, why NPG films formed from Au oxide films prepared by HV electrolysis at 300 V between times of 2 s to 15 s are more stable than those formed from Au oxides prepared by HV electrolysis at 540 V at the same times? Specifically, since for such short electrolysis times as at 2 s, no plasma was yet ignited around the POSC, but instead, normal electrolysis takes place according to the jt curves in Fig. . Thus, the Au oxide film formed under these different conditions must have some distinctly different structural properties, such as adhesion to the substrate in general or lateral interactions within the NPG film.