Synthesis, micellization properties, and cytotoxicity trends of N-hydroxyethyl-3-alkyloxypyridinium surfactants

N-hydroxyethyl-3-alkyloxypyridinium amphiphiles have been synthesized and characterized by various spectroscopic techniques. Self-assembling properties of these amphiphiles have been studied by surface tension, conductivity, and fluorescence measurements. Basic micellization parameters like critical micelle concentration (cmc), surface tension at the cmc (γ _cmc), adsorption efficiency (pC₂₀), effectiveness of surface tension reduction (Π _cmc), maximum surface excess concentration (Γ _max) and minimum surface area/molecule (A _min), and Gibbs free energy of the micellization (ΔG⁰ _mic) have also been determined. The micellization of these 3-alkyloxypyridinium halides in aqueous phase have been found to be exothermic and entropy-driven as assessed by conductivity measurements at different temperatures. Thermal degradation of these surfactants has also been assessed by thermal gravimetric analysis under nitrogen atmosphere. Further, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay of these surfactants on C6 glioma cells show them to be less toxic than conventional cationic surfactants.