Effect of Some Cationic Detergents on Macromolecularly Stabilised Emulsions with Special Reference to Sodium Alginate and Gum Arabic as Emulsifiers

Abstract

Abstract The effect of some cationic detergents viz. cetyl pyridinium bromide, lauryl pyridinium chloride and phenyl trimethyl ammonium chloride has been studied on stabilised by sodium alginate and gum arabic emulsions. Zeta potentials were measured at different concentrations of cationic detergents microelectrophoretically. The particle size was determined microphotographically. With the help of zeta potential and particle size the interaction energies were calculated by summing up attraction and repulsion energies in the light of D.V.O. theory. For attraction energy the van der Waals constant was computed theoretically from the optical data and was obtained to be 6.7×10−14 erg. The interaction energies thus obtained gave very high energy barriers which completely obviated the occurrence of flocculation in primary minima, causing flocculation to occur in secondary minima. The theoretical degrees of aggregation were calculated and plotted at different values of A. The flocculation occurring in the system was observed haemocytometrically by counting the number of singlets and doublets and the degrees of aggregation were calculated. With the help of observed degrees of aggregation the operating value of van der Waals constant has been estimated by interpolating them into the theoretical curves, which is an indirect approach to ascertain the value of van der Waals constant. The values of A obtained are 3.0×10−13 and 2.6×10−13 erg for sodium alginate and gum arabic systems respectively. The binding parameters, number of binding sites available and free energy of adsorption have also been calculated.