Structural properties of colloidal suspensions

Abstract

Structural properties of three- and two-dimensional colloids composed by hard spheres and/or by Yukawa particles, which can have different diameters and charges, are studied by solving the Ornstein-Zernike equation, together with Percus-Yevick, hypernetted chain and Rogers-Young approximations. From the partial radial distribution functions g ij ( r) the partial structure factors S ij ( k) are determined, and with them the compressibility structure factor S x ( k), the measured structure factor S M ( k) and the Bhatia-Thornton structure factors S NN ( k), S NQ ( k) and S QQ ( k). As an effect of diameter and/or charge polydispersity on the structure of binary mixtures, the position and height of the main peak of S M ( k), and its value at k = 0, change non-monotonously with the composition. In the case of binary mixtures of hard and Yukawa spheres the structure is given by two different scales. A liquid-solid phase transition induced by a change in the dimensionality was found for monodisperse systems.