Dresden 2017 – scientific programme
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BP: Fachverband Biologische Physik
BP 21: Posters - Membranes and Vesicles
BP 21.2: Poster
Tuesday, March 21, 2017, 14:00–16:00, P1A
Shear-thinning and shear-thickening of a confined suspension of vesicles — •Abdessamad Nait Ouhra1,2, Marine Thiébaud1, Othmane Aouane1,3, Hamid Ez-Zahraouy2, Abdelilah Benyoussef2, Christian Wagner3, and Chaouqi Misbah1 — 1Université Grenoble Alpes France — 2Université Mohammed V Rabat Maroc — 3Experimental Physics, Saarland University, Saarbrücken, Germany
Widely regarded as an interesting model system for studying flow properties of blood, vesicles are closed membranes of phospholipids that mimic the cytoplasmic membranes of red blood cells (RBCs). In this study we analyse the rheology of a suspension of vesicles in a confined geometry: the suspension, bound by planar planes on each side, is subjected to a shear flow. Flow properties are then anaylzed as a function of shear rate γ, the concentration of the suspension φ and the viscosity ratio λ=ηin/ηout, where ηin and ηout are the fluid viscosities of the inner (hemoglobin solution for RBC) and outer fluids, respectively. We find that the apparent (or effective viscosity) of the suspension exhibits either shear-thinning (decreasing viscosity with shear rate) or shear-thickening (increasing viscosity with shear rate). The shear thinning or thickening behaviors appear as subtle phenomena, dependant on viscosity contrast λ. We provide arguments about the possible sources of these phenomena.