The surface of an electrode is rarely, if ever, a homogenous surface. It is often incorrectly assumed to be in order to simplify data interpretation and mathematical modeling. However, a corroding metal will certainly have areas of both anodic and cathodic nature, and a sensor will have areas of varying surface conductivity. In a traditional bulk electrochemical measurement, the current from the entire working electrode is recorded. This gives an integrated response. It is then impossible to distinguish if the sample has a uniform response distributed evenly about its surface; or a small number of sites of much greater intensity.
The VersaSCAN consists of an advanced three-dimensional closed-loop (100-nm resolution) positioning system mounted onto an optical base. Depending on the ancillary equipment mounted onto or connected to this positioning system, the VersaSCAN can provide a breadth of information. As different as each of the techniques is, they have the common goal of providing localized information relative to the sample under investigation.