Europhys. Lett.
Volume 75, Number 6, September 2006
Page(s) 978 - 984
Section Interdisciplinary physics and related areas of science and technology
Published online 23 August 2006
Europhys. Lett., 75 (6), pp. 978-984 (2006)
DOI: 10.1209/epl/i2006-10209-3

Capillary attraction of charged particles at a curved liquid interface

Alois Würger

CPMOH, CNRS-Université Bordeaux 1 - 351 cours de la Libération 33405 Talence, France

received 26 June 2006; accepted in final form 27 July 2006
published online 23 August 2006

A recent experiment revealed the existence of an attractive pair potential of colloidal particles trapped on water droplets in an oil phase (Nikolaides M. G. et al., Nature 420, (2002) 299). We show that such a capillary attraction occurs for stronlgy charged particles at a curved interface, due to the incomplete compensation of the interface pressure and the counterforce on the particle. This attractive force varies as Z4 with the bare valency, and as (a0/R)4 with the ratio of particle size a0 and droplet radius R; it vanishes in the limit $R\rightarrow\infty$, i.e., for a flat interface.

82.70.-y - Disperse systems; complex fluids.

© EDP Sciences 2006