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

The adsorption and aggregation of mixed systems for ionic liquid (ILs) surfactants (1-decyl-3-methylimidazolium bromide, C10mimBr, 1-dodecyl-3-methylimidazolium bromide, C12mimBr, 1-hexadecyl-3-methylimidazolium bromide, C16mimBr) and non-ionic surfactant Triton X-100 in aqueous media have been investigated by surface tension measurements, electrical conductivity, 1H NMR and FTIR technologies. Surface properties have been determined such as critical micelle concentration (CMC), surface saturation adsorption (Γmax), minimum surface area per surfactant molecule (Amin), surface tension at the CMC (γCMC), adsorption efficiency (pC20), and surface pressure at the CMC (ΠCMC) 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 1H 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.