Mixtures of Hydrophobic Particles and Oils as Antifoamers

The synergetic antifoaming effect of mixtures of insoluble hydrophobic particles and hydrophobic oils, when dispersed in an aqueous medium, has been weU established in the patent Hterature. These mixed antifoamers are very effective at very low concentrations (10-100 ppm). The hydrophobic particles may be hydrophobised silica and the oil is PDMS. [Pg.338]

One possible explanation of this synergetic effect is that the spreading coefficient of the PDMS oil is modified by the addition of hydrophobic particles. It has been suggested that the oil-particle mixtures form composite entities where the particles can adhere to the oil/water interface. Subsequently, the presence of particles adhering to the oil/water interface may facilitate the emergence of oil droplets into the air/water interface, so as to form lenses leading to rupture of the [Pg.338]

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