Attraction between like-charge surfaces in polar mixtures
Department of Chemical Engineering and The Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev - 84105 Beer-Sheva, Israel
Accepted: 16 June 2011
We examine the force between two charged surfaces immersed in aqueous mixtures having a coexistence curve. For a homogeneous water-poor phase, as the distance between the surfaces is decreased, a water-rich phase condenses at a distance Dt in the range 1–100 nm. At this distance the osmotic pressure can become negative leading to a long-range attraction between the surfaces. The osmotic pressure vanishes at a distance De<Dt, representing a very deep metastable or globally stable energetic state. We give analytical and numerical results for Dt and De on the Poisson-Boltzmann level.
PACS: 64.70.Ja – Liquid-liquid transitions / 64.75.Xc – Phase separation and segregation in colloidal systems / 64.75.Jk – Phase separation and segregation in nanoscale systems
© EPLA, 2011