Effect of ZnO Nanoparticle and Hexadecyltrimethylammonium Bromide on the Dynamic and Equilibrium Oil–Water Interfacial Tension

The effect of ZnO nanoparticles on the dynamic and equilibrium interfacial tension in the presence and absence of cationic surfactant CTAB was investigated. The results show that nanoparticles solely have no effect on interfacial tension. However, in the presence of CTAB, both particles and surfactants are adsorbed at the interface, and by a synergistic effect decrease the interfacial tension more. The effect of ZnO nanoparticles on the contact angle and stability of emulsions was studied too. The dynamic interfacial tension data were fitted with two different models. The results show that the adsorption mechanism of surfactant from bulk to interface was controlled by the mixed diffusion-kinetic model.