PHASE-DIAGRAM OF A MODEL ADHESIVE HARD-SPHERE DISPERSION

Using various experimental techniques, the phase diagram of an adhesive hard-sphere dispersion is constructed. The dispersion exists of spherical silicium oxide particles coated with stearyl alcohol dispersed in benzene. In addition to the binodal and spinodal curves corresponding to a gas-liquid transition, a gel phase is found in which the Brownian particles form an interconnected static structure. The gas-liquid critical point is located at a volume fraction of 0.19. The gel line intersects the critical point. At smaller volume fractions the gel line is located below the spinodal curve, in the unstable region of the phase diagram. For larger volume fractions, the gel line is located above the binodal curve. We also report some preliminary light scattering experiments on spinodal decomposition. (C) 1995 Academic Press, Inc.