Hard sphere colloidal dispersions: Mechanical relaxation pertaining to thermodynamic forces

Abstract

The complex viscosity of sterically stabilized (hard) silica spheres in cyclohexane has been measured between 80 Hz and 170 kHz with torsion pendulums and a nickel tube resonator. The observed relaxation behaviour can be attributed to the interplay of hydrodynamic and thermodynamic forces. The validity of the Cox-Merz rule is checked.

The rheology of hard sphere suspensions at arbitrary volume fractions: An improved differential viscosity model

“…On the other hand, putting φ ef f = φ/φ c in the denominator of Eq. (14) we recover the empirical expression obtained by Krieger and Dougherty [18], Eq. (8).…”

“…The simple formulas reviewed are of fundamental importance for the understanding of the rheology of suspensions. However, these formulas are far from satisfactory since they only lead to good quantitative results in the low volume fraction regime [12,13,14].…”

Effect Of Inp Passivation On Carrier Recombination in InxGa1-xAs/GaAs Surface Quantum Wells

“…The behaviour of microgels dispersions below C m is similar to that exhibited by colloidal suspensions. This analogy is supported by the low-frequency dependence of the storage and loss moduli which vary as G (ω) ∼ ω 2 and G (ω) ∼ ω, just like in hard-sphere suspensions [8]. The divergence of the low-shear viscosity is associated with the appearance of slow relaxation modes which manifest themselves at low frequencies by a sudden drop in G (ω) and by a bump in G (ω) near C m .…”

Rheo-SANS Study of an Aqueous Suspension of Poly(Methyl Methacrylate-co-Styrene) Particle

“…In fact, the φ eff dependence of η 0 of the MS particles was in close agreement with the φ dependence seen for hard-core silica particles, 4) the latter being subjected to (almost) fully screened electrostatic interaction to have a negligibly thin electrostatic shell. This result suggested that the terminal relaxation of the MS suspensions corresponds to the relaxation of the thermodynamic stress, as similar to the situation in the hard-core suspensions: [4][5][6][7] The thermodynamic stress reflects a strain/flow-induced distortion in the spatial distribution of the particles and relaxes through the Brownian motion of the particles. [8][9][10][11][12] *: To whom correspondence should be addressed.…”