Hard Science at Soft Interfaces

Ecole Polytechnique Federale de Lausanne Department of Chemistry and Chemical Engineering, Switzerland 

Electrochemistry at soft interfaces is a very interesting topic, as many different types of charge transfer reactions can take place in parallel and concomitantly. The different charge reactions include (i) ion transfer reactions where the flux of ions crossing the interface gives rise to a current (ii) assisted ion transfer reactions where the extraction of, for example, an aqueous ion by an organic soluble ionophore also gives rise to an ionic current and (iii) 

Developments in Electrochemistry Science Inspired by Martin Fleischmann, First Edition. Edited by Derek Fletcher, Zhong-Qun Tian and David E. Williams. 

Usually, when thinking of electrochemical reactions, reactions are considered at a metal/electrolyte or semiconductor/electrolyte interface, but rarely about the interface between electrolyte solutions or, more recently, the electrolyte-ionic liquid interface or even the interface between two immiscible ionic liquids. 

If it is accepted that an electrochemical reaction is one where the Gibbs energy of the reaction depends on the potential difference between two phases, as well as temperature and pressure (as do classical chemical reactions), then charge transfer reactions at soft interfaces are truly electrochemical reactions. Indeed, their characteristic is to be potential-dependent and controlled by the Galvani potential difference between the two phases in contact. 

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