We are studying model liquid dispersions of spherical colloidal particles in contact with a flat solid surface, which is made of the same material as the particles. The particle-particle and particle-surface attractions are then increased by increasing the concentration of an added polymer depletant. Recent theoretical work by Per Linse and Håkan Wennerström has shown that in such a situation, for purely geometric reasons, the particles should adsorb to the infinite flat surface before phase separation occurs in the bulk. This prediction has been verified by ellipsometry for uncharged model systems (hydrophobically modified silica particles and silica surfaces in cyclohexane) and, also, for charged silica particles and surfaces in water. QCM and AFM are also used to study the surface phenomena.

People: Samia Ouhajji, Gerda Kamsma, Lennart Piculell, Tommy Nylander, A. Philipse and Remco Tuinier (University of Utrecht).

Contact person:Lennart Piculell