Thermodynamic and Interfacial Properties of DTABr/CTABr Mixed Surfactant Systems in Ethanolamine/Water Mixtures: A Conductometry Study

Abstract

Mixed-micelle formation in the binary mixtures of dodecyltrimethylammonium bromide (DTABr) and cetyltrimethylammonium bromide (CTABr) surfactants in water-ethanolamine mixed solvent systems has been studied by conductometric method in the temperature range of 298.1 to 313.1 K at 5 K intervals. It was observed that the presence of ethanolamine forced the formation of mixed micelle to lower total surfactant concentration than in water only. The synergistic interaction was quantitatively investigated using the theoretical models of Clint and Rubingh. The interaction parameter β12 was negative at all the mole fractions of DTABr in the surfactant mixtures indicating a strong synergistic interaction, with the presence of ethanolamine in the solvent system resulting in a more enhanced synergism in micelle formation than in water only. The free energy of micellization ΔGM values was more negative in water-ethanolamine mixed solvent system than in pure water indicating more spontaneity in mixed micelle formation in the presence of ethanolamine than in pure water.

Formation of Mixed Micelle in an Aqueous Mixture of a Surface Active Ionic Liquid and a Conventional Surfactant: Experiment and Modeling

“…The cmc values of the mixed surfactant solutions in conjunction with those of the pure components at different temperatures thus obtained are collected in Table . The cmc’s of aqueous HDMimCl and DTAB are found to be in good agreement with those reported in the literature. , The micellization process depends, in general, on two factors, namely, the electrostatic interactions between the charged headgroups of the mixing surfactant components and the hydrophobic interactions owing to their hydrocarbon tails. − In the present study, both HDMimCl and DTAB surfactant ions bear positive charges which would try to hinder the formation of mixed micelles. Thus, in the mixtures studied, the first factor opposes mixed micelle formation.…”

“…We have also obtained a similar trend for the values of Δ H M , indicating that translational energy loss by monomers and heat generation due to hydrophobic interaction is lesser than the energy absorbed by breaking the iceberg structure of water during micellization. Esan et al investigated the interactions of CTAB + DTAB in an aqueous medium. The values of Δ G M and β R are more negative for the CTAB + DTAB system than our system, indicating that micellization of HDMimCl + DTAB is less energetically feasible than that of the CTAB + DTAB system .…”

“…Esan et al investigated the interactions of CTAB + DTAB in an aqueous medium. The values of Δ G M and β R are more negative for the CTAB + DTAB system than our system, indicating that micellization of HDMimCl + DTAB is less energetically feasible than that of the CTAB + DTAB system . The values of Δ S M for all of the HDMimCl + DTAB mixtures are found to be positive, indicating that the degree of disorderliness increases due to micellization and that the entropy change is favorable.…”

“…The values of ΔG M and β R are more negative for the CTAB + DTAB system than our system, indicating that micellization of HDMimCl + DTAB is less energetically feasible than that of the CTAB + DTAB system. 43 The values of ΔS M for all of the HDMimCl + DTAB mixtures are found to be positive, indicating that the degree of disorderliness increases due to micellization and that the entropy change is favorable. From Table 4, it is apparent that the process of micellization gradually becomes more entropy-driven as the mixtures get richer in the HDMimCl, while the enthalpy factor somewhat overrides the entropy contribution in the DTAB-rich region.…”

Performance evaluation of non-ionic silicone surfactants OFX 0309 and DC 193C as a new approach in cloud point extraction – spectrophotometry for determination of atrazine in water samples

“…The positive values of Δ H ° 11.80 J mol −1 in CPE-OFX 0309 and 10.35 J mol −1 in CPE-DC 193C reflects to the endothermic natural of solubilisation affinity of atrazine in the micellar phases. 62 The endothermic nature was also shown by the increase in the amount of solubilisation with temperatures due to the increase number of hydrophobic micelles in surfactant rich phase while the CMC of the non-ionic surfactants decrease on increasing temperature. 63 Increasing the temperature was known to stimulate the rate of diffusion of atrazine in the external surface of surfactant and decrease the viscosity of the solution.…”