A mesoscopic rheological model of moderately concentrated colloids

Core--shell microgels as model colloids for rheological studies

We review recent work done on the rheology of thermosensitive suspensions. These systems consist of aqueous suspensions of coreshell particIes having asolid polystyrene core and a shell of thermosensitive crosslinked poly(N-isopropylacrylamide) (PNIPA). In cold water the thermosensitive PNIPA-network is swollen leading to a high effective volume fraction of the particles in suspension. Approach...

The rheological behavior of concentrated colloidal dispersions

A simple model for the rheological behavior of concentrated colloidal dispersions is developed. For a suspension of Brownian hard spheres there are two contributions to the macroscopic stress: a hydrodynamic and a Brownian stress. For small departures from equilibrium, the hydrodynamic contribution is purely dissipative and gives the high-frequency dynamic viscosity. The Brownian contribution h...

Local transient rheological behavior of concentrated suspensions

A structural analysis of concentrated, aggregated colloids under flow

Using both instantaneous snapshots and simulation generated scattering data, the steady-state ̄ ow behaviour of a concentrated aggregated colloidal suspension is analysed in terms of its structure factor S(k). We ® nd that in the shear thinning regime, unlike model hard sphere results, S(k) exhibits pre-peaks at small k, which we interpret as indicative of intermediate range order in the shear i...

Dynamics of concentrated hard-sphere colloids near a wall.

We investigate the Brownian motion of hard-sphere colloids near a solid wall by Evanescent Wave Dynamic Light Scattering (EWDLS). We carried out measurements for various volume fractions of sterically stabilized poly(methyl methacrylate) (PMMA) particles over a range of scattering wave vectors, q. While in the dilute regime, the near wall short-time diffusion is significantly slowed down due to...