Shear‐induced microstructural changes in flocculated suspensions of fumed silica

Non-Newtonian behaviour of flocculated suspensions

Structure of polymer solutions containing fumed silica.

Small angle neutron scattering is employed to estimate the interactions in complex multicomponent systems. The method is applied to describe a ternary system, poly(dimethyl siloxane) toluene with silica filler particles. Contrast variation by solvent deuteration is used to distinguish the three different partial structure factors of filled polymer samples, S(pp)(q), S(pf)(q), and S(ff)(q), wher...

Shear-Thickening Response of Fumed Silica Suspensions under Steady and Oscillatory Shear

Suspensions of fumed silica in polypropylene glycol exhibit shear-thickening under steady shear and "strain-thickening" under oscillatory shear. Strain-thickening refers to a sharp increase in the complex viscosity eta* observed at critical combinations of strain-amplitude and frequency. Two regimes of strain-thickening behavior have been found: The first occurs at high critical strains and low...

Flocculated suspensions from microstructure to macroscopic behavior

Emanuela Del Gado ETH Zürich Institut für Baustoffe (IfB), Schafmattstrasse 6 CH-8093 Zürich/Switzerland. [email protected] Gelation of Brownian and non-Brownian suspensions Modeling and numerical simulations gain significant insight into local processes and physical mechanisms underlying the interplay of gelation and flocculation in colloidal suspensions. We study local rearrangements, ...

Equilibrium-state Density Profiles of Centrifuged Cakes of Flocculated Suspensions

Many advanced ceramics are formed by colloidal consolidation using techniques such as sedimentation, centrifugation, or pressure filtration. In all these, the minimization of density variations of various colloidally-consolidated cakes has not been examined systematically until recently. Schilling et al.' used y-ray densitometry to study the density variations in a sedimented cake and showed th...