Multifactoring at a single electrode

An Ellipsometric Study of Surface Films on Copper Electrodes Undergoing Electropolishing

“…In the case of metals forming colored ions, a viscous liquid layer can be detected visually. This viscous liquid layer has been considered to be in contact with film-free metal (3)(4)(5)(6), with metal covered with an adsorbed layer of oxygen or anions (7)(8)(9), or with metal covered with oxide or salt layers varying in thickness from about one monolayer to several tens of angstroms (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21), according to the references quoted. This controversial situation has arisen most probably because the particular in situ methods used hitherto (impedance measurements, coulometry, current-potential curves) are not capable of yielding direct evidence about the thickness and nature of the film or films present.…”