Rheology of attractive emulsions

Rheology of attractive emulsions.

We show how attractive interactions dramatically influence emulsion rheology. Unlike the repulsive case, attractive emulsions below random close packing, φ(RCP), can form soft gel-like elastic solids. However, above φ(RCP), attractive and repulsive emulsions have similar elasticities. Such compressed attractive emulsions undergo an additional shear-driven relaxation process during yielding. Our...

Interface composition of multiple emulsions: rheology as a probe.

We have investigated the dynamic rheological properties of concentrated multiple emulsions to characterize their amphiphile composition at interfaces. Multiple emulsions (W1/O/W2) consist of water droplets (W1) dispersed into oil globules (O), which are redispersed in an external aqueous phase (W2). A small-molecule surfactant and an amphiphilic polymer were used to stabilize the inverse emulsi...

Vorticity alignment and negative normal stresses in sheared attractive emulsions.

Attractive emulsions near the colloidal glass transition are investigated by rheometry and optical microscopy under shear. We find that (i) the apparent viscosity eta drops with increasing shear rate, then remains approximately constant in a range of shear rates, then continues to decay; (ii) the first normal stress difference N1 transitions sharply from nearly zero to negative in the region of...

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 s...

Linking self-assembly, rheology, and gel transition in attractive colloids