Micellar Aggregation Of Gemini Surfactants In Aqueous Solution Studied By Fluorescence And Absorption Spectroscopy

Fluorescence and absorption spectroscopy are extensively used in the surfactant research. Because the environment that is surrounded a probe molecule strongly affects the probe's basic properties, and the probe exhibits spectral changes in different micellar environments. As a result, it is possible to use"well behaved"probes to detect the micellar structure. The critical micelle concentration (cmc), micellar aggregation number (N), micro-polarity etc are important structural parameters to characterize the self-assembly of surfactants. Generally, these parameters can be determined by fluorescence and absorption spectroscopy techniques. Thus it is very important to develop effective and convenient spectral methods for the surfactant research. In this master dissertation, we investigated the micellization of Gemini surfactant C11pPHCNa,12(n)-4-12(n)?2Br(n=1,2,3,4)and C12-3-C12?2Br by fluorescence and absorption spectroscopy in different respects. The main results are concluded as follows:1. The critical micelle concentration (cmc) of carboxylate gemini surfactant C11pPHCNa in aqueous solution at pH12 was determined by the self- absorption spectra of the p-dioxybenzene residue in the spacer to be 0.0891 mmol?L?1, which well agreeed with that measured by surface tension technique.2. It was found that the quenching of pyrene fluorescence in the micellization process of C11pPHCNa obeyed the Stern-Volmer equation. A jump was noted in the Stern-Volmer curve before and after the formation of micelle and the critical micelle concentration of...