DIFFUSION-LIMITED CURRENTS AT HEMISPHEROIDAL MICROELECTRODES

An analytical solution is presented to the problem of steady-state diffusion to a hemispheroidally shaped electrode resting on an infinite plane. Electrodes of a wide range of shapes are found to pass steady-state diffusion-limited currents that approximate nFDcb2πA 1 2 in magnitude so that the area A of the electrode largely determines the current, the effect of shape being minor. "Whisker" microelectrodes, however, contravene this generalization and show a pronounced shape effect. The short-time current at a hemispheroid is also reported; its time-independent component generally exceeds the steady-state current. Two modelling applications of hemispheroidal electrodes are suggested. © 1990.