Critical phenomena at electrosorption of organic compounds on electrodes

Abstract

Problems associated with the effect of surfactants on polarization characteristics of a liquid metal electrode-electrolyte interface, as well as the fluctuations of its adsorption coverage, are considered. For the effective adsorption potential, the analytical dependence of which on the state parameters is determined by a nonequilibrium surface pressure, an expression derived earlier in terms of a quasichemical approximation is proposed. It is shown that the excessive differential capacitance of the interface, associated with the specific adsorption of surfactants, turns to infinity on the spinodal. The relaxation and correlation of equilibrium fluctuations of the adsorption process completeness in the interface plane at different electrode potentials are studied. Expressions for the correlation length of fluctuation are obtained. Their fundamental importance as the natural scale for the size and the duration of a nanochemical process is discussed. It is shown that the relaxation time and the correlation radius of fluctuations turn to infinity at the adsorption phase stability limit.