Like-charged particles at a liquid liquid interface
by Tom Kodger
M.G. Nikolaides, A.R. Bausch, M.F. Hsu, A.D. Dinsmore, M.P. Brenner, C. Gay, D.A. Weitz and M. Megens, J. Aizenberg Nature Communications 424, August (2003);
Dipole, Electrostatics in oil, Interface distortion
This communication discusses a simple enigmatic attraction at an oil-water interface between like charged particles. The original paper (Nature 420, 299-310, 2002) claims that a distortion of the interface due to a diploar electric field induces a long range capillary attraction. Megens and Aizenberg claims= that this cannot be so due to a fundamental force balance. In this communcation, these authors claim that the range of the capillary distortion is only short ranged and insignifanct (10^-5 kT). The original authors then respond by acknowledging that their original response was not complete but defend their original approach of a capillary distortion. This is true when but only when the free charge density of the oil is accounted for, thus a large dipole imbalance can be created.
Capillarity In Action
The original paper claims an attactive potential of,
<math>U(r) = (F2/(2 π γ) * ln(r/r0)</math>