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Pullanchery_Droplets_stability.pdf (905.33 kB)

Communication: On the Stability and Necessary Electrophoretic Mobility of Bare Oil Nanodroplets in Water

submitted on 09.06.2020, 07:14 and posted on 11.06.2020, 05:19 by Saranya Pullanchery, Sergey Kulik, Halil I. Okur, Hilton. B. de Aguiar, Sylvie Roke
Hydrophobic oil droplets, particles and air bubbles can be dispersed in water as kinetically stabilized dispersions. It has been established since the 19th century that such objects harbor a negative electrostatic potential roughly twice larger than the thermal energy. The source of this charge continues to be one of the core observations in relation to hydrophobicity and its molecular explanation is still debated. What is clear though, is that the stabilizing interaction in these systems is understood in terms of electrostatic repulsion via DLVO theory. Recent work [Carpenter et al., PNAS 116 (2019) 9214] has added another element into the discussion, reporting the creation of bare near-zero charged droplets of oil in water that are stable for several days. Key to the creation of the droplets is a rigorous glassware cleaning procedure. Here, we investigate these conclusions and show that the cleaning procedure of glassware has no influence on the electrophoretic mobility of the droplets, that oil droplets with near-zero charge are unstable, and provide an alternative possible explanation for the observations involving glass surface chemistry.


Swiss National Science Foundation 200021-182606-1

EU MCSA-IF (899088)

LabEx ENS-ICFP: ANR-10-LABX-0010/ANR-10-IDEX-0001-02 PSL.


Email Address of Submitting Author


École Polytechnique Fédérale de Lausanne (EPFL)



ORCID For Submitting Author


Declaration of Conflict of Interest

Authors declare no conflict of interest