Influence of solvent, electrolytes, β-CD, OTAB on the krafft temperature too and aggregation of sodium tetradecyl sulfate

The krafft temperature (T-k) of sodium tetradecyl sulfate (STS) has been determined conductometrically in aqueous, different aquo-organic solvent media (dioxane, formamide, and ethylene glycol), different concentrations of additives viz. NaCI, beta-CD, and octadecyltrimethylammonium bromide (OTAB). The change in T-k in different media has been notified and summarized in tabular form. The micellar properties of STS also have been determined in binary aqueous mixtures of dioxane (DO) and formamide (FA) by tensiometry, conductometry and isothermal titration calorimetry. Different interfacial parameters, Gibbs surface excess (Gamma(max)), area minima per surfactant (A(min)), surface pressure (Pi(cmc)), and packing parameter (P) have been calculated from related wellknown equations. Thermodynamic parameters, such as free energy for micellization (Delta G(m)(0)), free energy of adsorption (Delta G(ads)(0)), change in enthalpy (Delta H-m(0))and entropy change associated with micellization (Delta S-m(0)) have been also deduced. Aggregation number and Stern Volmer constant of STS in DO and FA have been determined from steady state fluorescence quenching study using fluorimetric technique. (C) 2019 Elsevier B.V. All rights reserved.