Effect of Ultrasonication on Stability of Oil in Water Emulsions.

Abstract

Effect of ultrasonic waves on stability of oil in water system of light liquid paraffin oil (HLB = 12) as internal phase and tween20 (HLB = 16.7), span20 (HLB = 8.6) as emulsifying agents was studied. A comparison was made to determine the stability of emulsions prepared by mechanical agitation method and ultrasonication technique. Droplet size measurement method was used to determine the stability of emulsions. Physico-chemical parameters like concentration of emulsifying agent, volume fraction of dispersed phase, viscosity of continuous phase by adding glycerin to water were compared apart from the effect of emulsification time on stability of emulsions prepared with mechanical stirring and ultrasound. Ocular micrometer was used to determine the droplet size of the dispersed phase.Emulsions prepared by ultrasonic technique were found to be more stable for longer duration of time when compared to emulsions prepared by mechanical agitation which can be attributed to the small droplet size which is thermodynamically stabilized.Ultrasonic technique gave more stable emulsions than with mechanical agitation method. Emulsification time, volume fraction of dispersed phase, viscosity of continuous phase and concentration of emulsifying agents played a major role in the stability of emulsions. Keywords: Liquid paraffin, Tween 20, Span 20, emulsification, ultrasound technique, volume fraction of dispersed phase