Voltammetric Characterization of Liquid/Liquid Interfaces Modified with Cetyl-Trimethyl-Ammonium Bromide (CTAB)

Abstract

In this paper a voltammetric study of a three-phase system modified with the surfactant CTAB in a liquid/liquid interface is presented. The three-phase system consists of a nitrobenzene microdroplet (1µL) with 0.1 M ferrocene, immobilized in a paraffin impregnated graphite electrode and immersed in a LiClO 4 solution. Surfactant molecules present at the interface increase the ClO 4¯ ion transfer resistance at low concentrations, and the ferrocenium ion transfer at high concentrations. A current mapping of the ClO 4¯ ions around a nitrobenzene microdroplet using SECM is included. SECM results demonstrate that ionic transport takes place at the three-phase region, according to data published in the literature. Experimental data simulations using the finite element method qualitatively describe the system.