Role of Solid Emulgents in Emulsion Stability

The emulsifying behaviour of finely divided solid stabilizers has been studied in detail under different physico-chemical conditions. The solid emulgents used include freshly precipitated Fe(OH)₃ and Cr(OH)₃ and their colloidal sols specially the partially flocculated ones. The promotion of the emulsion stability has been ascertained both kinetically and in terms of interaction energies between the emulsion drop lets. The hydroxide stabilized emulsions are found to be most stable (insensitive to the addition of electrolytes and heat). Partially flocculated sols promote reasonably stable emulsions, but the sols as such act as weak emulgents. Relatively high stability of the emulsions is mainly due to (i) their large size which leads to only secondary minimum flocculation and (ii) solidous nature of compact consistency of the emulgent film which prevents the drainage of the oil underneath.