Detection of Water-in-Oil Droplet Formation within an Interfacial Region Formed by an Aqueous/1, 2-Dichloroethane Interface Using Transient Cell Impedance Measurements at a Single High Frequency

Abstract

The detection of water-in-oil (w/o) droplet formation within an interfacial region formed by an interface between an aqueous phase and 1,2-DCE using transient impedance measurements in an unconventional electrochemical cell is herein reported. Droplet formation causes a large peak-like increase in transient real cell impedance. Peaks are likely caused by significant decrease in ion concentration within the interfacial region by formation of w/o droplets containing electrolyte. Droplet formation and an accompanying interfacial stability was observed when antagonistic salts (consisting of a hydrophobic ion of \({\rm{\Delta }}G_{{\rm{tr}}}^{^ \circ ,{\rm{water}} \to 1,2 - {\rm{DCE}}} \le \) TBA⁺) were mixed with conventional aqueous electrolytes in the aqueous phase. The instability manifests as Marangoni convection, causing rapid mass transport in the adjacent fluid on both sides of the liquid/liquid interface.