Industrial & Engineering Chemistry Research, Vol.49, No.18, 8532-8537, 2010
Improvement of Wetting Properties of Colloid Silica Binders
Wetting properties of colloid silica binders modified by addition of surfactants were investigated. Perfluorononanoic, an anionic surfactant, the nonionic fluorinated surfactant Zonyl FSO-100, the nonionic commercial surfactant Rokafenol, and their mixtures were studied. As a model silica binder, a 30% colloid dispersion of SiO2 in water was used, which was compared with the commercial binder Sizol, also based on colloid silica. The size of particles in these dispersions was determined by dynamic light scattering and by the atomic force microscopy imaging of particles deposited on mica. The zeta potential of particles was measured by microelectrophoresis. The dynamic surface tension and contact angles of binders on a paraffin substrate was determined by drop shape analysis. Our investigations showed that the Zonyl-FSO surfactant and its mixture with Rokafenol effectively reduced the dynamic contact angle to a value of 18 degrees. Such low contact angles represent a significant improvement in comparison with commercial binders.