Screened electrostatics of charged particles on a water droplet
CPMOH, CNRS-Université Bordeaux 1, 351 cours de la Libération, 33405, Talence, France
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Published online: 17 January 2006
We study the electrostatic properties of charged particles trapped at an interface in a water-in-oil microemulsion. The electrostatic potential and the counterion distribution in the water droplet are given in terms of the ratio of the Debye screening length κ-1 and the droplet radius R. In the limit R→∞ we recover the well-known results for a flat interface. Finite-size corrections are obtained in terms of the small parameter 1/κR. Part of the counterions spread along the interface and form a charged layer of one Debye length thickness. In particular, there is a uniform surface charge contribution. We derive explicit expressions for the electric field, the mobile charge density, and the charge-induced pressure on the interface.
© EDP Sciences/Società Italiana di Fisica/Springer-Verlag, 2006