Regular irregularity in the transfer of anionic surfactant across the liquid/liquid interface.

Abstract

Irregular current spikes and other anomalies seen in voltammetry of the transfer of anionic surfactants, alkyl sulfonates, and alkyl sulfates across the 1,2-dichloroethane/water (DCE/W) interface are reproducible. The anomalies have a certain regularity that is predicted by a recently proposed concept, the electrochemical instability. Irregular current spikes follow after the augmentation of the current induced when the phase-boundary potential is brought close to the mid-point potential of the transferring surfactant ions. Potential-step chronoamperometry clearly demonstrates the presence of the instability window, that is, the potential region where the interface becomes unstable only in the limited range of the phase-boundary potential.