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Accueil > Publications > Archives 2004-2010 > 2006

Yielding and Flow in Adhesive and Nonadhesive Concentrated Emulsions

L. Bécu, S. Manneville, and A. Colin — Phys. Rev. Lett. 96 (2006) 138302

publié le

The nonlinear rheological response of soft glassy materials is addressed experimentally by focusing on
concentrated emulsions where interdroplet attraction is tuned through varying the surfactant content.
Velocity profiles are recorded using ultrasonic velocimetry simultaneously to global rheological data in
the Couette geometry. Our data show that nonadhesive and adhesive emulsions have radically different
flow behaviors in the vicinity of yielding : while the flow remains homogeneous in the nonadhesive
emulsion and the Herschel-Bulkley model for a yield stress fluid describes the data very accurately, the
adhesive system displays shear localization and does not follow a simple constitutive equation, suggesting
that the mechanisms involved in yielding transitions are not universal.