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Title:Electrostatic, electrokinetic, and ordering properties of concentrated suspensions of polystyrene latex
Author(s):Voegtli, Leo Paul
Doctoral Committee Chair(s):Zukoski, Charles F.
Department / Program:Chemical and Biomolecular Engineering
Discipline:Chemical Engineering
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Engineering, Chemical
Abstract:The electrokinetic properties of polystyrene latexes are investigated and data reduction indicates that surface charge regulation occurs through the adsorption of ions from the suspending medium. An independent non-electrokinetic method of determining ionic adsorption is developed confirming these results. Changes in particle surface properties and interaction potentials with volume fraction are examined with a model that indicates surface properties change little with volume fraction at moderate surface potentials and when the average particle separation is not too small. Further tests of how surface properties change with suspension volume fraction and fluid phase ionic strength are carried out by developing a model of suspension thermodynamic properties based on pair interactions. The statistical mechanical technique correctly predicts suspension osmotic pressures and the order/disorder phase transition.
The study of the thermodynamic properties of concentrated suspensions of polystyrene latex indicates that these properties can be accurately predicted using hard sphere perturbation theory if the particle surface chemistry is understood. As a large portion of the particle surface charge is determined by ion adsorption, charge regulation as volume fraction or fluid phase ionic strength are altered is expected to play a large role in determining suspension properties at elevated volume fractions. The success of the models developed in this thesis indicates that the most important variable is the change of particle charge with ionic strength. As a consequence of the weak dependence of charge upon volume fraction, the low volume fraction characterization of surface charge can be used in predicting the thermodynamic properties of concentrated suspensions.
Issue Date:1989
Rights Information:Copyright 1989 Voegtli, Leo Paul
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9011063
OCLC Identifier:(UMI)AAI9011063

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