Abstract
Nine sulfate-type hybrid surfactants with an ethylene spacer in their molecule, CmF2m+1C2H4CH(OSO3Na)CnH2n+1 (FmEHnOS: m = 4, 6, 8; n = 3, 5, 7), were synthesized. FmEHnOS were obtained in a yield higher than those for the hybrid surfactants previously synthesized. While FmEHnOS were hardly susceptible to hydrolysis in aqueous weakly acidic through strongly alkaline media, these surfactants were hydrolyzed in highly acidic media to give alcohol derivatives, FmEHnA. They were highly water-soluble and highly surface-active. Their critical micelle concentrations (cmc) determined by surface tension measurements were about 3.5 times higher than those of sulfate-type hybrid surfactants with a benzene ring spacer, CmF2m+1C6H4CH(OSO3Na)CnH2n+1 (FmPHnOS: C6H4 = p-phenylene), and the cmcs were found to obey the Klevens’ rule. Changes in the chemical shifts of ω-CF3 and ω-CH3 groups in the NMR spectra of the newly synthesized surfactants at different concentrations suggested that the fluorocarbon and hydrocarbon chains in F4EH3OS micelles undergo an intramicellar phase separation. Thermoresponsive surfactant gel formation was observed for 10 wt% F8EH3OS solution.
