Abstract: Rheo-Physics of Shear Thickening Fluid Suspoemulsions (2011 Annual Meeting)

Monday, October 17, 2011

Exhibit Hall B (Minneapolis Convention Center)

Prachi Thareja¹, Ingo Hoffmann², Matthew W. Liberatore³, Matthew E. Helgeson⁴, Thomas Hu⁵, Michael Gradzielski² and Norman J. Wagner⁶, (1)Chemical Engineeirng, University of Delaware, Newark, DE, (2)Institut für Chemie Technische Universität Berlin, Berlin, Germany, (3)Department of Chemical Engineering, Colorado School of Mines, Golden, CO, (4)Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, (5)Research and Development, Unilever, Trumbull, CT, (6)Chemical Engineering, University of Delaware, Newark, DE

The rheological behavior and microstructure of branched, cationic worm like micellar (WLM) solutions of 40 mM erucyl bis(hydroxyethyl)methylammonium chloride (EHAC) is studied as a function of added salt (sodium salycilate) concentration, temperature, and shear rate via Rheo-Small-Angle Light Scattering (Rheo-SALS). These WLM solutions exhibit shear enhanced concentration fluctuations leading to induced phase separation (SIPS), manifested as visual turbidity under shear and the appearance of a characteristic "butterfly" scattering pattern in Rheo-SALS experiments. Flow kinematics measurements in a Couette geometry are used to determine the relationship between SIPS and shear banding i.e., the splitting of the viscometric flow into shear bands with different local shear rates. Modeling using the Giesekus constitutive equation aids in discrimination between banding and non-banding solutions. The combination of Rheo-SALS, dynamic rheology, velocimetry, and constitutive equation modeling allows detailed exploration of the relationship between SIPS, shear banding, fluid microstructure and the equilibrium phase behavior.

Extended Abstract: File Not Uploaded

See more of this Session: Poster Session: Fluid Mechanics
See more of this Group/Topical: Engineering Sciences and Fundamentals