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Ionic liquids as modulators of the critical micelle concentration of sodium dodecyl sulfate

2004; Elsevier BV; Volume: 35; Issue: 2 Linguagem: Inglês

10.1016/j.colsurfb.2004.02.014

1873-4367

Ayse Beyaz, Woon Su Oh, V. Prakash Reddy,

Photochemistry and Electron Transfer Studies

Critical micelle concentration (CMC) of sodium dodecyl sulfate (SDS), an anionic surfactant, has been investigated in aqueous solutions of a variety of room temperature ionic liquids (RTILs): 1,3-dimethylimidazolium iodide (Me2IM-I, 2), 1-butyl-3-methylimidazolium chloride (BMIM-Cl, 3), 1-hexyl-3-methylimidazolium chloride (HxMIM-Cl, 4), 1-methyl-3-octylimidazolium chloride (MOIM-Cl), 5, and 1-methyl-3-octylimidazolium tetrafluoroborate (MOIM-BF4, 6). The CMC of SDS is shown to correlate with the nature of the alkyl groups in the RTILs; SDS showed appreciably higher CMCs in presence of ionic liquids 2 and 3, whereas in the presence of ionic liquids 4, 5, and 6 much smaller CMCs were observed. The nature of the gigenions, Cl− or BF4−, has no noticeable effect on the observed CMC values.