EFFECTS OF THE DIMENSIONALITY ON THE STRUCTURE OF COLLOIDAL SUSPENSIONS

The average ordering of colloidal particles in suspension changes duri ng 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 t his to happen: first, the interaction between particles is now also me diated, and hence modified, by the walls, and second, a spatial degree of freedom is hindered. Effects of the latter type, referred to as ef fects of the dimensionality, are studied in this work, from a theoreti cal point of view, for colloidal suspensions of charged and uncharged hard spheres. They are studied by comparing the structure of three- an d two-dimensional systems without considering any modification in the interparticle pair potential. We show that the system may undergo phas e transitions induced by the change in its dimensionality. (C) 1996 Ac ademic Press, Inc.