A unified new analytical approximation for positive feedback currents with a microdisk SECM tip

Analytical approximations for steady-state positive feedback currents in scanning electrochemical microscopy (SECM) experiments using a microdisk are discussed. The use of a conformal map transformation leads to the use of new mathematical functions. A general analytical expression for all values of tip–substrate distances and all types of microdisk (with various insulator thicknesses) are thus obtained with only four adjustable parameters.