Mixed micellization and surface properties of non-ionic/cationic surfactants

摘要

We investigate the surface properties of aqueous binary mixtures of our cationic surfactant O-dodecyl-N,N '-diisopropylisourea hydrochloride (ISO-DIC C-12) with commercially available nonionic surfactant polyoxyethylene p-(1,1,3,3-tetramethylbutyl)phenyl ether (TritonX-100) at different temperatures (288 to 303 K). The micellization behavior of the binary systems is studied by determining the surface tension and other important physicochemical parameters, such as the critical micelle concentration (CMC), surface tension at the CMC(gamma(cmc)), Krafft Temperature (T-K), maximum excess concentration (Gamma(max)), minimum surface area per molecule (A(min)), surface pressure at the CMC (n(cmc)), and the adsorption efficiency (pC20) at the air/water interface. The study has additionally covered the calculation of thermodynamic parameters of micellization, including the standard Gibbs free energy, the standard enthalpy, the standard entropy, the free energy, and the Gibbs free energy of adsorption at air/water interface. The CMC values of the binary systems determined by experimental data are used to evaluate the micellar composition in the mixed micelle, the interaction parameter beta and the activity coefficients f(1)(ISO-DIC C-12) and f(2) (polyoxyethylene p-(1,1,3,3-tetramethylbutyl)phenyl ether) using the theoretical treatment proposed by Clint and Rubingh. Our results reveal that the proposed binary systems possess enhanced surface activity compared to those of the individual surfactants.