On the stability and necessary electrophoretic mobility of bare oil nanodroplets in water
Résumé
Hydrophobic oil droplets, particles, and air bubbles can be dispersed in water as kinetically stabilized dispersions. It has been estab-lished since the 19th century that such objects harbor a negative electrostatic potential roughly twice larger than the thermal energy. Thesource of this charge continues to be one of the core observations in relation to hydrophobicity, and its molecular explanation is stilldebated. What is clear though is that the stabilizing interaction in these systems is understood in terms of electrostatic repulsion via Der-jaguin, Landau, Verwey, and Overbeek theory. Recent work [A. P. Carpenteret al., Proc. Natl. Acad. Sci. U. S. A.116, 9214 (2019)]has added another element into the discussion, reporting the creation of bare near-zero charged droplets of oil in neat water that arestable for several days. Key to the creation of the droplets is a rigorous glassware cleaning procedure. Here, we investigate these con-clusions and show that the cleaning procedure of glassware has no influence on the electrophoretic mobility of the droplets and that oildroplets with near-zero charge are unstable. We provide an alternative possible explanation for the observations involving glass surfacechemistry.
Domaines
Physique [physics]Origine | Fichiers éditeurs autorisés sur une archive ouverte |
---|
Loading...