The focus of this research was to identify and quantify interfacial concentrations of micellar counter-ions using the method of chemical trapping as a means to determine the second critical micelle concentration (CMC), denoting the shift from spherical micelles to rod-like ones in Gemini surfactants. This investigation is concerned with two counter-ions: bromide and ortho-fluorobenzoate salt, an aromatic counter-ion that would increase tight packing of the micelle and induce the rod transition at a lower concentration than bromide. Possible products of chemical trapping in micelles were synthesized and quantified using HPLC to provide normalized data for the Chemical trapping experiments. These normalized results show that as surfactant concentrations increase in the bromide trapping and as o-fluorobenzoate concentrations increase in the other experiments, tighter packing at the micellar interface corresponds to a decrease in trapped water product. The benzoate salt trappings, however, do not show significant increase in the ester trapped product, instead being outweighed by production of base-catalyzed indazole product formation. This formation needs to be controlled before significant conclusions can be drawn from the data. More data points need to be taken in the presumed CMC locations before any significant conclusions about rod-transitions at those concentrations can be made.

Investigation of the rod transition in micelles of 12-3-12 and 12-4-12 Gemini surfactants using chemical trapping

251st National Meeting (2016)

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