Stabilization of water-in-oil emulsions with complex of silica particles and hexylamine

The properties of emulsions stabilized by complexes of silica particles with hexylamine are analyzed. It is shown that water-in-oil emulsions were obtained only if the hexylamine volume fraction was greater than that of the silica (Aerosil) volume fraction in the aqueous phase. So, in the case of water-in-oil emulsions, hexylamine is a completely equivalent co-stabilizer together with silica, rather than just a solid surface modifier. It is assumed that at high concentrations this short-chain surfactant, together with silica, forms hybrid organic-inorganic particles that are attached at the oil/water interface and promotes the formation of oil droplets in the water.