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

B. R. Silver B. R. Silver
Российский электрохимический журнал
Abstract / Full Text

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.

Author information
  • Biophysical Chemistry Department, J. Heyrovský Institute of Physical Chemistry of the CAS, v. v. i. c, Prague 8, Prague, 18223, Czech Republic

    B. R. Silver

  1. Silver, B.R., Holub, K., and Mareček, V., Spontaneous emulsification at surfactantless liquid/liquid interfaces, J. Electroanal. Chem., 2017, vol. 805, p. 91.
  2. Sadakane, K., Onuki, A., Nishida, K., Koizumi, S., and Seto, H., Multilamellar structures induced by hydrophilic and hydrophobic ions added to a binary mixture of D2O and 3-methylpyridine, Phys. Rev. Lett., 2009, vol. 103, no. 16, p. 167803.
  3. Sadakane, K. and Seto, H., Membrane formation in liquids by adding an antagonistic salt, Front. Phys., 2018, vol. 6, p. 26.
  4. Onuki, A., Yabunaka, S., Araki, T., and Okamoto, R., Structure formation due to antagonistic salts, Curr. Opin. Colloid Interface Sci., 2016, vol. 22, p. 59.
  5. Marecek, V., Electrochemical monitoring of the co-extraction of water with hydrated ions into an organic solvent, Electrochem. Commun., 2018, vol. 88, p. 57.
  6. Silver, B.R., Holub, K., and Mareček, V., Ion transfer kinetics at the micro-interface between two immiscible electrolyte solutions investigated by electrochemical impedance spectroscopy and steady-state voltammetry, J. Electroanal. Chem., 2014, vol. 731, p. 107.
  7. Bard, A.J., Faulkner, L.R., Leddy, J., and Zoski, C.G., Electrochemical Methods: Fundamentals and Applications, New York: Wiley, 1980, vol. 2.