Variation of interfacial tension by nanoclay particles in oil-in-water emulsions

Abstract

To investigate whether nanoclay particles vary with the interfacial tension of oil-in water emulsion, interfacial tension is measured using dynamic drop volume method. From the critical volume of a single droplet at the moment of detachment, interfacial tension is calculated based on the force balance between gravity force and capillary force. The interfacial tension of a droplet is reduced by the addition of nanoclay and the interfacial tension reduction is further varied depending on nanoclay type. The addition of hydrophilic nanoclay particles (5000 ppm) in an oil drop reduces the interfacial tension from 31.4 to 19.6 mN/m by interfacial localization. In the case of organically modified nanoclay (5000 ppm), interfacial tension is only slightly reduced from 31.4 to 26 mN/m. This study shows that nanoclay effectively reduces the interfacial tension of a droplet when nanoclay is located at the interface.