STRUCTURAL-PROPERTIES OF COLLOIDAL SUSPENSIONS

Structural properties of three- and two-dimensional colloids composed by hard spheres and/or by Yukawa particles, which can have different d iameters and charges, are studied by solving the Omstein-Zernike equat ion, together with Percus-Yevick, hypernetted chain and Rogers-Young a pproximations. From the partial radial distribution functions g(ij)(T) the partial structure factors S-ij(k) are determined, and with them t he compressibility structure factor S-chi(k), the measured structure f actor 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 o n the structure of binary mixtures, the position and height of the mai n 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 sp heres the structure is given by two different scales. A liquid-solid p hase transition induced by a change in the dimensionality was found fo r monodisperse systems.