Abstract
The solution behavior of ionic surfactant in brine and oil was studied in the presence of cosurfactant such as long-chain alcohol. In this system, ionic surfactant changes from lipophilic (oil-soluble) to hydrophilic (water-soluble) with increasing temperature. Hydrophile-lipophile property of ionic surfactant is just balanced at certain temperature (HLB-temperature) at which three-phase consisted of water, oil and surfactant phases appears. HLB-temperature goes up with increasing salt or cosurfactant contents whereas it decreases by using longer chain hydrocarbon (oil), or shorter chain cosurfactant. From these phenomena, Hydrophile-Lipophile-Balances of ionic surfactants were estimated. The order of hydrophilic ionic surfactants is R8SO3Na>R8_??_SO3Na>R12OSO3Na(R12N(CH3)3Cl)>R11COONa>R15COONa>Aerosol OT.
The stability and the types of emulsion were also studied in these ionic surfactant system. The emulsion types change from W/O to O/W at HLB-temperature. The effect of temperature on the stability of emulison is reversed to that of nonionic surfactant system.
