Stabilization Of Dispersions By The Surfactants
STABILIZATION OF DISPERSIONS BY THE SURFACTANTS
AND POLYMERS
M. M. Soltys, Z. M. Yaremko, V. D. Havryliv
Ivan Franko National University of L’viv, Chemical Department,
Kyryla & Mefodiy Str. 6, L’viv, 79005, Ukraine, e-mail: soltys@franko.lviv.ua
The aggregate stability of aqueous dispersions depends significantly on distribution of counter-ions around charged colloid particles.
Distribution of low-molecular counter-ions in diffuse part of a double electrical layer depends on the nature and concentration of electrolytes and is defined by the Poisson-Boltzmann equation. Surfactants and polymers are widely used for the regulation of dispersion properties, however, their influence on the distribution of counter-ions in the adsorption layer is not finally established.
If adsorption isotherms of low-molecular substances allow to make certain conclusions about the structure of the adsorption layer, adsorption isotherms of the surfactants and polymers are less informative in this respect. Therefore, the study of electrophoretic mobility of colloid particles and aggregate stability of dispersions in solutions of surfactants and polymers invokes significant interest.
The results of complex investigation of aqueous dispersions of titanum dioxide in solutions of the following surfactants TRITON CF-10, ATLAS-G3300, DEXTROL OC.50, TAMOL-731, Polymethacrylic acid - PMAA-10) are discussed in this report.
The model is proposed that takes into account both the change in surface potential of particles and the change in the position of a sliding plane during electrophoretic movement of particles in the electric field due to the adsorption on the surface of particles of surfactants and polymers.
The mutual influence of surfactants and electrolytes as well as mutual influence of low (TRITON CF-10) and high (PMAA-100) surfactants on the aggregative stability of aqueous dispersions of titanium dioxide are discussed within the framework of this model.
The influence of methods of introduction of surfactants in titanium dioxide dispersions on their aggregative stability and stability as to the action of low-molecular electrolytes has been confirmed experimentally.
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