US EPA

3859910 

Journal Article 

Thermodynamic Study of Aggregation of Cholinium Perfluoroalkanoate Ionic Liquids 

Florindo, C; Tome, LC; Marrucho, IM 

2016 

Yes 

Journal of Chemical and Engineering Data
ISSN: 0021-9568
EISSN: 1520-5134 

American Chemical Society 

61 

12 

3979-3988 

English 

10.1021/acs.jced.6b00455 

WOS:000389623400004 

To advance the ionic liquid (IL) platform to tailor fluorinated surfactant properties, the aim of this work is to evaluate the surfactant properties of cholinium-based salts bearing perfluoroalkanoate anions. Novel surfactant ILs containing the cholinium cation [Ch](+) combined with different perfluoroalkanoate anions, namely perfluoropentanoate [PFPent](-), perfluorohexanoate [PFHex](-), perfluoroheptanoate [PFHept](-), and perfluorooctanoate [PFOct](-), were synthesized. The critical micelle concentrations (CMCs) were determined using an ionic conductivity method, at different temperatures. Thermodynamic parameters of micellization were also evaluated. The results indicate that the CMC value decreases in a linear manner with the increment of the fluoroalkyl chain length in the anion. The evaluation of the thermodynamic parameters shows that the micellization is spontaneous and entropically driven and that the enthalpy of micellization is very small. It was also observed that the introduction of the cholinium cation in these surfactants allows for smaller CMC values when compared to that of other tetraalkylammonium-based surfactants with the same fluorinated anions, in short to more efficient and green surfactants. This result is probably due to counterion association and not to counterion binding to micelle surface.