Aggregation Behavior of a Fluorinated Surfactant in 1-butyl-3-methylimidazolium Bis(trifluoromethylsulfonyl)imide Ionic Liquid

Na Li, Shaohua Zhang, Liqiang Zheng, Tohru Inoue

Langmuir. 2009 Sep 15;25(18):10473-82.

PMID: 19441844

Abstract:

The cationic fluorinated surfactant, FC-4, unlike other surfactants, forms micelles in the room temperature ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (bmimTf2N). Surface tension, freeze-fracture transmission electron microscopy, 19F NMR, 1H NMR, and Fourier transform infrared measurements revealed that (i) the FC-4 cation forms an ion pair with the Tf2N anion, (ii) the ion pairs undergo association to form premicellar aggregates, and (iii) the premicellar aggregates transform into micelles at the critical micelle concentration (CMC). The thermodynamic parameters for micelle formation derived from the temperature dependence of the CMC demonstrated that the solvophobic interaction between the solvophobic tails of the surfactant molecules is rather weak in bmimTf2N compared with other ionic liquids, in accordance with the observation that surfactants do not readily form micelles in bmimTf2N. The fact that FC-4 forms micelles in such an inconvenient solvent is attributed to the ion-pair formation between the surfactant cation and the ionic liquid anion.

Chemicals Related in the Paper:

Catalog Number	Product Name	Structure	CAS Number	Price
AP174899833	1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide		174899-83-3	Price