Fusion of emulsion particles to the polarized 1,2-dichloroethane ∣ water interface

Abstract

Current–potential curves at the interface between the 1,2-dichloroethane (DCE) solution of Aerosol-OT (AOT, sodium diisooctyl sulfosuccinate, DOSS −Na +) and the aqueous solution of LiCi (W) show unusual current spikes, which are distinctly different from the curves predicted from the diffusion-controlled transfer of Na + ions across the interface. After the initial negative current, presumably corresponding to the transfer of Na + ions from DCE to W, the current reduces to the level of that of the base solution and concomitantly whitish emulsions become visible only in the DCE side of the interface. Then intermittent current spikes appear. The quantity of electric charge transferred by a single current spike far exceeds the charge that one emulsion particle bears, suggesting the avalanche-type transfer of many emulsion particles across the interface. Video-imaging of the interface demonstrates that the current spikes are triggered by the fusion to the interface of a large water droplet probably formed by the coalescence of W/O emulsion particles in the bulk of the DCE phase.