Kinetics of condensation of adenine at the mercury vertical bar electrolyte interface

The kinetics of phase transitions of adenine adsorbed on mercury are studie d by chronocoulometry and chronoamperometry from aqueous 0.1 M KClO4 and 0. 5 M NaF solutions. Experimental conditions have been selected to minimise, in the overall kinetic response, the contribution of the initial current de cay, due to double-layer charging and the adsorption step. The transients c orrected for these fast initial contributions present a peaked shape and ca n be described by the classical theory for nucleation and growth. The poten tial dependences of the rate constants of nucleation and growth have been o btained from double potential step experiments. The analysis of the condens ation kinetics according to the classical nucleation theory leads to the ev aluation of the line tension, and the Gibbs energy of formation of a critic al cluster and its size. (C) 2001 Elsevier Science B.V. All rights reserved .