ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 42, Number 5
JKCSEZ 42(5)
October 20, 1998 

The critical micelle concentration (CMC*) and the counterion binding constant (B) in a micellar state of the mixed surfactant systems of dodecylpyridinium chloride (DPC) with dodecyltrimethylammonium bromide (DTAB), tetradecyltrimethylammonium bromide (TTAB), and cetyldimethylethylammonium bromide (CDEAB) were determined at 25℃ as a function of αl (the overall molc fraction of DPC) by the use of electric conductivity method. Various thermodynamic parameters (Xi, γi, Ci, aiM, β, ΔHmix, and ΔGmo) for the micellization of DPC/DTAB, DPC/TTAB, and DPC/CDEAB mixtures were calculated and analyzed for each system by means of the equations derived from the pseudophase separation model. The results show that the DPC/DTAB mixed system has the greatest deviation and the DPC/CDEAB mixed system has the smallest deviation from the ideal mixed micellar model.