Effect of Emulsifier Concentration and Type on the Particle Size Distribution of Emulsions

Abstract

Two series of mineral oil/water emulsions containing varying amounts of emulsifier, either sodium dodecyl sulfate or polysorbate 80, were studied over a 2-year period. The Coulter counter was used to determine particle size distributions at various time intervals. For each emulsifier, there is a minimum concentration above which the emulsions are stable for over 2 years with little change in particle size distribution. Increasing surfactant concentration causes decreasing median particle size in both series according to a logarithmic relationship. Some of the theoretical aspects of surfactant adsorption at the oil/water interface are discussed. Two series of mineral oil/water emulsions containing varying amounts of emulsifier, either sodium dodecyl sulfate or polysorbate 80, were studied over a 2-year period. The Coulter counter was used to determine particle size distributions at various time intervals. For each emulsifier, there is a minimum concentration above which the emulsions are stable for over 2 years with little change in particle size distribution. Increasing surfactant concentration causes decreasing median particle size in both series according to a logarithmic relationship. Some of the theoretical aspects of surfactant adsorption at the oil/water interface are discussed.