Modulations in Self-Organization Properties of Surfactant in Aqueous Ionic Liquid Media
Harsh Kumar, Arjuna Katal, Naval Kishor Rawat
Abstract
Abstract Ionic liquids (ILs) give a wide scope of favorable applications due to their much-upgraded properties. The strong electrostatic interactions between the cationic moiety of IL and the anionic surfactant play a very important role in the assembly of the large aggregates. We have investigated the aggregation behavior of anionic surfactants and IL in aqueous solution. Different temperatures and concentrations of IL have been taken to study the effect on critical micelles concentrations of surfactant. The critical micelle concentration values obtained by conductivity measurements are further confirmed by the fluorescence studies. The method is based on the fit of the experimental obtained raw data of fluorescence spectroscopy to a simple nonlinear category of a Boltzmann type sigmoidal function. Thermodynamical parameters of micellization <m:math xmlns:m="http://www.w3.org/1998/Math/MathML"> <m:mrow> <m:mi>Δ</m:mi> <m:msubsup> <m:mi>H</m:mi> <m:mi>m</m:mi> <m:mn>0</m:mn> </m:msubsup> </m:mrow> </m:math> $\Delta H_{m}^{0}$ , <m:math xmlns:m="http://www.w3.org/1998/Math/MathML"> <m:mrow> <m:mi>Δ</m:mi> <m:msubsup> <m:mi>G</m:mi> <m:mi>m</m:mi> <m:mn>0</m:mn> </m:msubsup> </m:mrow> </m:math> $\Delta G_{m}^{0}$ and <m:math xmlns:m="http://www.w3.org/1998/Math/MathML"> <m:mrow> <m:mi>Δ</m:mi> <m:msubsup> <m:mi>S</m:mi> <m:mi>m</m:mi> <m:mn>0</m:mn> </m:msubsup> </m:mrow> </m:math> $\Delta S_{m}^{0}$ have been considered to study the effect of aqueous IL 1-butyl-3-methylimidazolium bromide concentration and temperature on aggregation behavior of surfactant sodium dodecyl sulfate. FT-IR spectra have been studies to verify the structural changes arise in the aqueous IL and surfactant system.