Aggregation behaviors of mixed systems for imidazole based ionic liquid surfactant and Triton X-100

Abstract

Abstract The adsorption and aggregation of mixed systems for ionic liquid (ILs) surfactants (1-decyl-3-methylimidazolium bromide, C 10 mimBr, 1-dodecyl-3-methylimidazolium bromide, C 12 mimBr, 1-hexadecyl-3-methylimidazolium bromide, C 16 mimBr) and non-ionic surfactant Triton X-100 in aqueous media have been investigated by surface tension measurements, electrical conductivity, 1 H NMR and FTIR technologies. Surface properties have been determined such as critical micelle concentration (CMC), surface saturation adsorption ( Γ max ), minimum surface area per surfactant molecule ( A min ), surface tension at the CMC (γ CMC ), adsorption efficiency ( pC 20 ), and surface pressure at the CMC ( Π CMC ) as well as thermodynamic parameters of micellization. The surface tension measurements revealed that the addition of Triton X-100 into ILs can decrease CMC of ILs, suggesting that it is beneficial to the mixed micelle formation. Consistent with the results of surface tension, electrical conductivity measurement demonstrate a small degree of counter-ion binding to form mixed micelles, which may increase with the addition of TX-100. The 1 H NMR data and FT-IR analysis demonstrated the presence of hydrogen-bond between the imidazolium cation of ILs and the PEO units of Triton X-100 and hydrophobic interactions between the alkyl chain of the imidazolium cation and the hydrophobic chain with phenyl of Triton X-100.