Faculty of Chemistry, University of Ljubljana, Aškerèeva 5, 1000 Ljubljana, Slovenia
The sedimentation equilibrium of adhesive spheres mimicking a system of interacting spherical colloidal particles in suspensions in planar pores with adhesive (adsorbing) walls was studied on the basis of the solution to the hypernetted chain/Ornstein Zernike equation. The increasing interparticle adhesive attraction together with the gravity lead to the overall effect on particles to occupy the region of lower altitudes in the pore. It is found that at sufficiently strong stickiness the dense "substrate" being formed at the bottom of the pore behaves as a "condensation nucleus" for the condensation of particles from the bulk phase, the effect predominating the natural tendency of strongly adhesive particles to avoid the confined system. In the case of strongly adsorbing walls, the density profiles show a discontinuity in the slope at a distance of one particle diameter from the wall-fluid contact planes as a consequence of the exclusion volume of adsorbed monolayers. Due to gravity, this and other features are much more pronounced at the lower wall than at the upper one of the same adhesiveness.