8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

P9.56Tue 611:23-14:00Structural signature of a brittle-to-ductile transition inself-assembled networksLaurence Ramos, 1 Arnaud Laperrousaz, 1 Philippe Dieudonné, 1 and ChristianLigoure 11 L2C, Université Montpellier 2, 34095, Montpellier, FranceWe have designed a novel class of transient self-assembled networks by reversibly bridging surfactantmicelles with telechelic polymers. By changing in a controlled fashion the morphologyof the micelles (from sphere to rod to entangled wormlike micelles), one is able to tune both thelinear visco-elasticity and the non linear rheology of the networks. A transition from qualitativelydifferent flow curves is observed when the morphology of the micelles varies. We couple rheologyand time-resolved structural measurements, using Synchrotron small-angle X-ray scattering,in order to characterize the transition. We show that a close parallel between the fracture of solidsand the fracture of visco-elastic fluids under shear can be drawn, and propose a structural basis forthe characterization of the brittle or ductile nature of viscoelastic fluids. Our experiments whichcombine structural information and concomitant rheology measurements provide an unambiguoussignature of the brittle to ductile transition in viscoelastic fluids.56