Temperature- and Composition-Induced Multiarchitectural Transitions in the Catanionic System of a Conventional Surfactant and a Surface-Active Ionic Liquid

Abstract

The mixture of the cationic surfactant, cetyltrimethylammonium bromide (CTAB), and anionic surface-active ionic liquid, 1-butyl-3-methylimidazoliumdodecyl sulfate (bmimDS), has been studied as a function of the mole fraction of CTAB, X CTAB , with the total surfactant concentration fixed at 50 mM using turbidity measurements, rheology, dynamic light scattering, differential scanning calorimetry, small-angle neutron scattering, and small-angle X-ray scattering techniques. The catanionic mixture has been found to exhibit phase transitions from vesicles to micelles as a function of temperature, with some mole fractions of CTAB showing dual transitions. Solutions of X CTAB = 0.2 to 0.5 exhibited a single transition from vesicles to cylindrical micelles at 45 °C. With an increase in the mole fraction of CTAB from 0.55 to 0.65, dual structural transitions at 30 and 45 °C were observed. The microstructural transition at 30 °C is ascribed to the vesicle aggregation process with smaller vesicles fusing into bigger ones, whereas the transition at 45 °C was evaluated to be the vesicle-to-cylindrical micelle transition. However, at higher mole fractions of CTAB, X CTAB from 0.65 to 0.90, a single transition from vesicles to small cylindrical/spherical micelles was observed in the solutions, at a lower temperature of 30 °C. To the best of our knowledge, such a microstructural transitions as a function of temperature in a single mixture of cationic and anionic surfactants without any additive has not been reported so far.

Dual pH- and Thermo-Sensitive Poly(N-isopropylacrylamide-co-allylamine) Nanogels for Curcumin Delivery: Swelling–Deswelling Behavior and Phase Transition Mechanism

“…As shown in Figure 6c, the p(NIPAm-co-Am) NG solution had a relatively low absorption at 25 • C, which might be attributed to the presence of a transparent and linear polymer structure at that temperature. However, at temperatures over 42 • C, substantial UV-vis absorption was found, which might be related to temperature-induced micelle generation, which induces solution turbidity [25].…”

Cataleptogenic Effect of Haloperidol Formulated in Water-Soluble Calixarene-Based Nanoparticles

“…A possible explanation for this effect is the lower curvature of the vesicle surface, which ensures interaction with a larger surface of mucin compared to micellar particles. It should be additionally emphasized that, similar to micellar aggregates, the vesicles spontaneously formed in the binary system VC10–Hal are dynamic assemblies that can be subjected to structural rearrangements under different stimuli including temperature induced changes [ 40 , 41 ].…”

Effect of Cetyl Pyridinium Chloride on Corrosion Inhibition Properties of Mild Steel in Acidic Medium

“…Protonated pyridinium's functional group is adsorbed at anodic sites to prevent iron dissolution and at cathodic sites to halt the hydrogen evolution reaction [43][44][45][46]. This implies that the anodic and cathodic partial responses are regulated by the CPC through a multimodal inhibitory mechanism [46][47][48][49][50][51][52][53]. The fact that the CPC molecules adhere to the mild steel surface implies that, depending on their concentration, they self-aggregate there to form a variety of stripes that are uniformly wide, regularly spaced, and well-organized.…”