Coadsorption of 3-methylisoquinoline molecules and perchlorate ions at the mercury—aqueous solution interface

Abstract

The coadsorption of 3-methyl-isoquinoline (3-MeisoQ) and perchlorate ions has been examined at the mercury—aqueous solution interface by various electrocapillary methods. As a function of the surfactant and anion concentrations, three distinct superficial films have been characterized. At very negative potentials, the perchlorate ions are excluded from the condensed film formed by vertically oriented 3-MeisoQ molecules. At less negative potentials, a transition delimits a region of existence of a mixed film where the superficial organization differs only from that prevailing more negatively by the presence of the adsorbed perchlorate. The third film is present mainly in dilute solutions of 3-MeisoQ or perchlorate.