| The properties of micellization of surfactant play important roles in the biomimeticsynthesis of inorganic materials, and it is significant to study the self-assemblyproperties of surfactants in complex systems. In this paper, the self-assemblyproperties of surfactant in its ethanol-water mixtures with different ethanolcomposition were studied. Firstly, steady-state fluorescence measurements were carried out to study theassembly properties of surfactant in ethanol-water mixture, and the critical micelleconcentration and aggregation numbers of surfactant cetylmethylammonium bromidewere measured. It was revealed that with the increasing of the ethanol fraction in themixture, the critical micelle concentration increased significantly and the aggregationnumber decreased. A thermodynamic model of surfactant cetyltrimethylammonium bromide (CTAB)self-assembly in ethanol-water mixtures was set up on the basis of the thermodynamicfree energy model of aqueous surfactant solutions. The critical micelle concentration,the aggregation number, the free energy of micellization and the micellar sizedistribution of CTAB were calculated and compared with experimental data. Thisthermodynamic model can accuratetely estimate above parameters. Based on thethermodynamic calculation, it is indicated that the transfer free energy of thesurfactant tail is the main contribution leading to a negative value of the total freeenergies in the micellization. And with the ethanol concentration increasing, thiscontribution becomes larger than in pure water. Finally, dissipative particle dynamics (DPD) was adopted to simulate theself-assembly properties of CTAB in ethanol-water mixture. And with the increase ofsurfactant concentration, the aggregation morphology will display several structures,such as spherical micelle, mixed micelle of sphere and rod, rod micelle, and lamellarmicelles. Acting as structure breaker and increasing the solubility of surfactant,ethanol in the solution retards the formation of micelles.
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