Anomalous pH dependent stability behavior of surfactant-free nonpolar oil drops in aqueous electrolyte solutions

Lucy Y. Clasohm, Ivan Uriev Vakarelski, Raymond R. Dagastine*, Derek Y.C. Chan, Geoffrey W. Stevens, Franz Grieser

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

37 Scopus citations

Abstract

Recent advances in atomic force microscopy (AFM) force measurement techniques have allowed the direct measurement and theoretical interpretation of the interaction between a liquid droplet and a solid surface or between two liquid droplets. In this study, we investigated the interaction across an aqueous thin film between fluorocarbon (perfluoropentane) droplets, hydrocarbon (tetradecane) droplets, and a droplet and a flat mica surface in the absence of stabilizers. It was found that even at a relatively elevated electrolyte concentration of 0.1 M NaNO3, depending on the solution pH, interactions between two identical droplets or a droplet and a mica surface could be repulsive. A simple theoretical analysis of the magnitude and range of these interactive forces suggests that the DLVO theory cannot explain the observed behavior. The measured force behavior is discussed in the context of ion adsorption, and the arising charging effects, at the bare oil-water interface.

Original languageEnglish (US)
Pages (from-to)9335-9340
Number of pages6
JournalLangmuir
Volume23
Issue number18
DOIs
StatePublished - Aug 28 2007

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

Fingerprint Dive into the research topics of 'Anomalous pH dependent stability behavior of surfactant-free nonpolar oil drops in aqueous electrolyte solutions'. Together they form a unique fingerprint.

Cite this