Differential Effective Medium Theory (D-EMT) is applied to derive expressions for the viscosity of a colloidal suspension or an emulsion as a function of the volume fraction of the dispersed phase. The application of D-EMT to this problem depends on how the solvent liquid is partitioned between mobile liquid, solvated liquid, and liquid entrapped in flocculated clusters. The resulting equation for viscosity depends on whether or not the volume of mobile liquid is conserved as the concentration of dispersed phase is increased. The approach is a more generalized analog of one used by Pal and Rhodes to derive a viscosity-concentration equation , and the present approach provides a more rigorous basis for their result. Finally, we derive expressions that relate suspension composition to a solvation factor that is the ratio of the effective volume of the dispersed phase to its true volume. The solvation factor has important applications in determining the stability and rheological properties of colloidal suspensions.
Citation: Journal of Colloid and Interface Science
Pub Type: Journals
viscosity, differential effective medium theory, solvation factor