Rheology on the Way from Dilute to Concentrated Emulsions

The short review presents the analysis of the consecutive evolution of the rheology of emulsions starting from dilute systems (behavior of an individual liquid droplet in a continuous liquid phase) till the highly concentrated emulsions, in which droplets loose their spherical shape and become polygons. Along with the increase of the internal phase concentration, this is the transition from a simple Newtonian fluid via non-Newtonian fluid and up to a plastic medium demonstrating solid-like behavior at low shear stresses, yield stress threshold and non-Newtonian time-dependent properties. The special features of the emulsions rheology are related to the droplet deformation, orientation in flow, break-up and interdroplet interaction in concentrated emulsions. The similarities and differences in the rheology of suspensions and emulsions are discussed. Copyright © 2010 Praise Worthy Prize S.r.l. All rights reserved.