Abstract: The concept of effective concentration of surfaetant in membrane phase has been proposed,considering the high ad-sorption density of the surfactant at the droplet interfaces in LSM system.The effective concentration of surfactant,C_2,can be estimated by Eq.(7)—(9).The swelling caused by emulsification during the initial dispersion process was investigated.The swelling rate wasmeasured by a density method.A model for estimating the“Emulsification”swelling rate,F_(se),has been proposed,basedon a mechanism of swelling due to the entrainment of water resulted from the interracial turbulence and emulsification inthe initial dispersion process.It has been found that Eq.(26)gives excellent fit to the experimental data of Fujinawa,etal.and of the authors.