COLLOIDAL INTERACTIONS IN PARTIALLY QUENCHED SUSPENSIONS OF CHARGED-PARTICLES

We report measurements of the effective pair potential between charged colloidal particles in a bidimensional matrix of fixed obstacles. A b inary mixture of polystyrene spheres in water is confined between two glass plates. The larger particles are trapped by the plates in a diso rdered configuration with respect to which the smaller species of part icles equilibrates. The structures of both the mobile and the fixed sp ecies are measured by videomicroscopy. The pair potential, obtained by deconvoluting the structural information via the Ornstein-Zernike equ ation, exhibits two attractive components.