Micro-rheology of soft glassy materials: Collective phenomena in concentrated emulsions

In previous studies, non local effects have been evidenced and modeled [1, 2]. The fluidity is the number of rearrangement of droplets by unit of time, and appears to be a critical parameter to describe experimental data. In the present work, flows of flocculated and non-flocculated concentrated emulsions within Hele-Shaw cells are investigated. Fast confocal imaging is used to determine fluidity and cooperative length, and the Kinetic Elasto-Plastic model is challenged for systems with different interdroplet attractions\\[4pt] [1] J. Goyon, A. Colin, G. Olvarlez, A. Ajdari, and L. Bocquet, Nature 454 (2008) 84-87.\\[0pt] [2] L. Bocquet, A. Colin, and A. Ajdari, PRL 103 (2009).