The micellar and thermophysical studies of a surfactant, sodium dodecyl sulfate with a hydrotrope, 3-Nitrobenzene sulfonic acid sodium salt

In the current study, the micellization properties of a conventional surfactant, sodium dodecyl sulfate (SDS) in absence and presence a fixed concentration of (additive) hydrotrope (3-Nitrobenzene sulfonic acid sodium salt (NBS)) in water at various temperatures were reported. The conductivity was used to measure the critical micelle concentration (CMC) of mixed surfactant-hydrotrope systems. In the mixed systems the value of CMC decreases when the concentration of the hydrotrope is increased which gives better performance than the individual system and synergistic effects were observed. The thermodynamic parameters ∆G°mic, ∆S°mic, ∆H°mic evaluated and were found ∆G°mic values negative, which indicates the spontaneity of the mixed system. The effect of temperature on the density, dynamic viscosity was also examined and the results indicate that the density and dynamic viscosity decreases with increasing the temperature of the system. Nuclear magnetic resonance spectroscopy (NMR) and Fourier transformed infrared spectroscopy (FTIR) confirms the non-covalent interaction of mixed surfactant-hydrotrope systems. The results could be useful in industrial applications. Plot of specific conductivity vs. concentration of anionic surfactant sodium dodecyl sulfate (SDS) in the presence of 10 mM 3-Nitrobenzene sulfonic acid sodium salt at different temperature. [Display omitted] •The CMC value decrease with increase in hydrotrope concentration.•Synergistic effects were observed in mixed surfactant-hydrotrope system.•Mixed micelles are formed which are foremost to individual system.•The density and viscosity value decrease with increase in temperature.•NMR & FTIR confirms non-covalent interaction of mixed surfactant-hydrotrope system.