Effect of dicationic ionic liquids on cloud points of tergitol surfactant and the formation of aqueous micellar two-phase systems

authors	Bender, CR; Vicente, FA; Kuhn, BL; Frizzo, CP; Villetti, MA; Carvalho, PJ
nationality	International
journal	JOURNAL OF MATERIALS SCIENCE
abstract	A cloud point evaluation was performed for the nonionic surfactant Tergitol 15-S-7 in aqueous solutions of McIlvaine buffer (pH 7.0). Cloud point temperatures of the selected nonionic surfactant were studied in relation to the effect that the addition of dicationic ionic liquids (ILs) had on the systems. The dicationic ILs with different alkyl spacer lengths were derived from 1, n-bis(3-methylimidazolium-1-yl)alkane bromide ([BisAlk(MIM)(2)][2Br]) - in which Alk=But, Hex, Oct, and Dec. The dicationic ILs with longer alkyl spacer chains (Alk >= 6) led to an increase in the Tergitol's cloud point values, due to their ability to fold their structures in solution, which increase the interactions of ILs with tergitol in the mixed micelles. This increase was even more pronounced when the concentration of the dicationic ILs was increased. Furthermore, the addition of dicationic ILs increased the micelles size; however, the hydrodynamic diameter of mixed micelles did not depend on the length of the ILs' alkyl spacer chains. The Tergitol/IL systems with lower critical micellar concentration values will result in higher cloud point values, due to the greater colloidal dispersion stability.
publisher	SPRINGER
issn	0022-2461
isbn	1573-4803
year published	2021
volume	56
issue	21
beginning page	12171
ending page	12182
digital object identifier (doi)	10.1007/s10853-021-06055-1
web of science category	12
subject category	Materials Science, Multidisciplinary
unique article identifier	WOS:000640466300001