Comparative Study on the Micellization of SDS/Brij 30, DBS/Brij 30, and SDS/DBS Mixed Surfactant Systems in Pure Water

摘要

The critical micelle concentration (CMC) and the counter ion binding constant (B) for the mixed micellizations of DBS (sodium dodecylbenzenesulfonate), SDS (sodium dodecylsulfate), and Brij 30 (polyoxyethylene(4) lauryl ether) at 25 oC in pure water were determined by the use of electric conductivity and surface tension measuring methods. Various thermodynamic parameters (Xi, ￥?i, Ci, ai M, ￥a, and ￥?Hmix) were calculated and compared with each other mixed surfactant system by means of the equations derived from the nonideal mixed micellar model. The results show that the SDS molecule interacts more strongly with Brij 30 molecule than DBS molecule and that the SDS/Brij 30 mixed surfactant system has the greatest negative deviation from the ideal mixed micellar model and the SDS/DBS mixed system has followed almost the ideal mixed micellar model.