THE CASE OF TWO-DIMENSIONAL PHASE-TRANSITIONS INVOLVING SURFACTANTS AT THE WATER MERCURY INTERFACE

many organic surfactants, which are dissolved in an aqueous electrolyte in contact with a mercury electrode, adsorb in the form of compact monolayer films which are strongly stabilized by lateral attractions of the Fowler-Frumkin type. For some systems, a two-dimensional phase transition separates two distinct phases, which are characterized by different molecular orientations and may be either liquid- or solid-like monolayers. The elucidation of the nature and properties of the adsorbed layers is based on experimental results obtained at equilibrium as well as under non-steady state conditions.