Double layer electrical conductivity as a stability criterion for concentrated colloidal suspensions
authors Cruz, RCD; Segadaes, AM; Oberacker, R; Hoffmann, MJ
nationality International
journal COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
author keywords Colloidal interactions; Particle conductivity; DLVO; Electrokinetics; Alumina
keywords CHARGED-PARTICLES; POLYELECTROLYTES; ADSORPTION; KINETICS; FORCES; DLVO
abstract The slightly attractive inter-particle equilibrium potential associated with electrostatically stabilized suspensions of minimum viscosity is described by the DLVO theory and commonly gauged by static zeta-potential measurements, plagued with experimental uncertainties. In this work, the electrokinetic mobility of alumina particles was measured in suspensions prepared with selected solids content and ionic strength, as well as was the electrical conductivity of each suspension and suspending liquid. Particles electrical conductivity was then calculated and related to the colloidal stability described by the DLVO theory, enabling the identification of a processing window for the stability control of concentrated suspensions. The maximum repulsive potential and distance between particles (similar to 46 nm) corresponds to the particles maximum conductivity. When the particles conductivity is zero, the diffuse layer is fully collapsed and they stand at the minimum reversible distance (similar to 7 nm). At the equilibrium conductivity, a potential" curve is produced with a secondary attractive minimum of similar to 1.5 kT at an inter-particle distance of similar to 17 nm, as suggested by the DLVO theory and the Equipartition of Energy theorem. The condition for accurate measurement of static zeta-potential occurs at the isoconductivity point between particles and suspending liquid. 2017 Elsevier B.V. All rights reserved.
publisher ELSEVIER SCIENCE BV
issn 0927-7757
year published 2017
volume 520
beginning page 9
ending page 16
digital object identifier (doi) 10.1016/j.colsurfa.2017.01.059
web of science category Chemistry, Physical
subject category Chemistry
unique article identifier WOS:000401401100002
  ciceco authors
  impact metrics
times cited (wos core): 1
journal impact factor (jcr 2016): 2.714
5 year journal impact factor (jcr 2016): 2.838
category normalized journal impact factor percentile (jcr 2016): 55.517
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