Effects of the dimensionality on the structure of colloidal suspensions

The average ordering of colloidal particles in suspension changes during the process of reducing one spatial dimension, for example, when a finite volume of the suspension is squeezed between two plates until a quasi-two-dimensional system is produced. There are two reasons for this to happen: first, the interaction between particles is now also mediated, and hence modified, by the walls, and second, a spatial degree of freedom is hindered. Effects of the latter type, referred to as effects of the dimensionality, are studied in this work, from a theoretical point of view, for colloidal suspensions of charged and uncharged hard spheres. They are studied by comparing the structure of three- and two-dimensional systems without considering any modification in the interparticle pair potential. We show that the system may undergo phase transitions induced by the change in its dimensionality. (C) 1996 Academic Press, Inc.