Electrorheology of Suspensions of Mesostructured
and Mesoporous Silica in Poly(dimethylsiloxane)

A. V. Agafonov, T. A. Nefedova, and O. I. Davydova

Institute of Chemistry of Solutions, Russian Academy of Sciences, ul. Akademicheskaya 1, Ivanovo, 153045 Russia

Received November 21, 2007

Abstract—The effect of electric fields on the viscosity and shear stress of dispersions of mesostructured silicon
dioxide powders and the products of their thermal treatment, that is, mesoporous silicas, in silicone oil is inves-
tigated. Mesostructured silicon dioxide powders are prepared using different structuring reagents, namely, octy-
lamine, dodecylamine, and polyethylenimine. It is shown that the shear stresses developing in systems contain-
ing mesostructured powders as dispersed phases under the action of electric fields are several times higher than
those in dispersions of mesoporous materials. The shear stresses developing in the systems containing powders
of mesostructured materials as dispersed phases under the effect of electric fields depend on the nature of
organic substrates present in pores and the conductivity of the systems. Electrorheological effect in dispersions
of mesoporous silicas slightly depends on the structure of the materials. The observed synergism may be related
to the interactions between the components of a mesostructured material, which manifest themselves as a rise
in interfacial polarization. The stress–strain curves were measured upon tensile and compression in electric
fields of different strengths.

DOI: 10.1134/S1061933X08050013

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