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Title: Viscoelastic and rheological behavior of concentrated colloidal suspensions

Abstract

Molecular approaches are discussed to the density ({phi}), viscoelastic ({omega}), and rheological ({gamma}) behavior of the viscosity {eta}({phi}, {omega}, {gamma}) of concentrated colloidal suspensions with 0.3 < {phi} < 0.6, where {phi} is the volume fraction, {omega} the applied frequency, and {gamma} the shear rate. These theories are based on the calculation of the pair distribution function P{sub 2}(r; {omega}, {gamma}), where r is the relative position of a pair of colloidal particles. The linear visoelastic behavior {eta}({phi}, {omega}, {gamma} = 0) follows from an equation for P{sub 2}(r, {omega}, {gamma}) derived from the Smoluchowski equation for small {phi}, generalized to large {phi} by introducing the spatial ordering and (cage) diffusion typical for concentrated suspensions. The rheological behavior {eta}({phi}, {omega} = 0, {gamma}) follows from an equation for P{sub 2}(r; {gamma}) of a dense hard-sphere fluid derived from the Liouville equation. This leads to a hard-sphere viscosity {eta}{sup hs}({phi}, {gamma}) which yields the colloidal one {eta}({phi}, {gamma}) by the scaling relation {eta}({phi}, {gamma})/{eta}{sub 0} = {eta}{sup hs}({phi}, {gamma})/{eta}{sub B}, where {eta}{sub 0} is the solvent viscosity, {eta}{sub B} is the dilute hard-sphere (Boltzmann) viscosity, and the {gamma}`s are appropriately scaled. {eta}({phi}, {omega}) and {eta}({phi}, {gamma}) agree well with experiment. Amore » unified theory for {eta}({phi}, {omega}, {gamma}) is clearly needed and pursued.« less

Authors:
 [1];  [2]
  1. Delft Univ. of Technology (Netherlands)
  2. Rockefeller Univ., New York, NY (United States)
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
50770
Report Number(s):
CONF-940633-
Journal ID: IJTHDY; ISSN 0195-928X; TRN: 95:003581-0005
DOE Contract Number:  
FG02-88ER13847
Resource Type:
Journal Article
Journal Name:
International Journal of Thermophysics
Additional Journal Information:
Journal Volume: 15; Journal Issue: 6; Conference: 12. symposium on thermophysical properties, Boulder, CO (United States), 19-24 Jun 1994; Other Information: PBD: Nov 1994
Country of Publication:
United States
Language:
English
Subject:
66 PHYSICS; COLLOIDS; VISCOSITY; DENSITY; RHEOLOGY; BEHAVIOR; BOLTZMANN-VLASOV EQUATION; SUSPENSIONS

Citation Formats

Schepper, I.M. de, and Cohen, E G.D. Viscoelastic and rheological behavior of concentrated colloidal suspensions. United States: N. p., 1994. Web. doi:10.1007/BF01458826.
Schepper, I.M. de, & Cohen, E G.D. Viscoelastic and rheological behavior of concentrated colloidal suspensions. United States. https://doi.org/10.1007/BF01458826
Schepper, I.M. de, and Cohen, E G.D. Tue . "Viscoelastic and rheological behavior of concentrated colloidal suspensions". United States. https://doi.org/10.1007/BF01458826.
@article{osti_50770,
title = {Viscoelastic and rheological behavior of concentrated colloidal suspensions},
author = {Schepper, I.M. de and Cohen, E G.D.},
abstractNote = {Molecular approaches are discussed to the density ({phi}), viscoelastic ({omega}), and rheological ({gamma}) behavior of the viscosity {eta}({phi}, {omega}, {gamma}) of concentrated colloidal suspensions with 0.3 < {phi} < 0.6, where {phi} is the volume fraction, {omega} the applied frequency, and {gamma} the shear rate. These theories are based on the calculation of the pair distribution function P{sub 2}(r; {omega}, {gamma}), where r is the relative position of a pair of colloidal particles. The linear visoelastic behavior {eta}({phi}, {omega}, {gamma} = 0) follows from an equation for P{sub 2}(r, {omega}, {gamma}) derived from the Smoluchowski equation for small {phi}, generalized to large {phi} by introducing the spatial ordering and (cage) diffusion typical for concentrated suspensions. The rheological behavior {eta}({phi}, {omega} = 0, {gamma}) follows from an equation for P{sub 2}(r; {gamma}) of a dense hard-sphere fluid derived from the Liouville equation. This leads to a hard-sphere viscosity {eta}{sup hs}({phi}, {gamma}) which yields the colloidal one {eta}({phi}, {gamma}) by the scaling relation {eta}({phi}, {gamma})/{eta}{sub 0} = {eta}{sup hs}({phi}, {gamma})/{eta}{sub B}, where {eta}{sub 0} is the solvent viscosity, {eta}{sub B} is the dilute hard-sphere (Boltzmann) viscosity, and the {gamma}`s are appropriately scaled. {eta}({phi}, {omega}) and {eta}({phi}, {gamma}) agree well with experiment. A unified theory for {eta}({phi}, {omega}, {gamma}) is clearly needed and pursued.},
doi = {10.1007/BF01458826},
url = {https://www.osti.gov/biblio/50770}, journal = {International Journal of Thermophysics},
number = 6,
volume = 15,
place = {United States},
year = {1994},
month = {11}
}