Detail:
Abstract: Surface forces are conventionally interpreted under constant charge or constant potential conditions. But constant potential is a special case involving charge transfer between solution and surface. Other charging mechanisms include charge regulation, competitive site binding, and redox charging of electrodes. In each case the forces are influenced by the nonelectrostatic physisorption energy of potential determining ions. This results in distinct surface forces where some charging mechanisms lead to purely attractive forces while others show repulsion. A true constant potential condition may be set up without charge transfer at all, corresponding to an electrode (supercapacitor) charged by an external power source. We also review how forces may be described with charge exchange throughout the volume of a layer rather than at the surface. This modification to theory is required in order to properly model surface forces with polymeric layers.
