Co-solvent Effect on Spontaneous Formation of Large Nanoscale Structures in Catanionic Mixtures in the Anionic-Rich Region

Abstract

The aggregation behavior was investigated in mixtures of sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) (anionic-rich catanionic) solutions. The study was conducted in solutions of water-ethylene glycol (EG) by means of surface tension, conductometry, cyclic voltammetry, zeta potential measurements, transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques. The degree of counterion dissociation (α), critical micelle concentration, aggregation numbers, interfacial properties, interparticle interaction parameters, and morphology of aggregates were determined. Based on regular solution theory, the cosolvent effects between SDS and CTAB as surfactants were also analyzed for both mixed monolayers at mixed micelles (β M) and the air/liquid interface (β σ). It was shown that the formation of large aggregates occurred in the presence of an excess of anionic surfactant. A phase transition from cylindrical micelles to spherical micelles in the anionic-rich regime was observed with an increase in the EG volume fraction. The inter particle interactions were assessed in terms of cosolvent effects on the micellar surface charge density and the cylindrical-to-spherical morphology change. Zeta potential and size of the aggregates were determined using dynamic light scattering and confirmed the models suggested for the processes taking place in each system.

Troubleshooting the influence of trace chemical impurities on nanoparticle growth kinetics via electrochemical measurements

“…This can increase the size of micelles and cause more disorder and/or patterns of interdigitation in hydrocarbon tails. 29–41 Solvent molecules in even low concentrations can also cause chaotropic effects that can affect the behavior of micelles and bilayers, and presumably also of other solutes. 29,33…”

“…This can increase the size of micelles and cause more disorder and/or patterns of interdigitation in hydrocarbon tails. [29][30][31][32][33][34][35][36][37][38][39][40][41] Solvent molecules in even low concentrations can also cause chaotropic effects that can affect the behavior of micelles and bilayers, and presumably also of other solutes. 29,33 Generalizability of the acetone and iodide adjustment scheme to all batches of BioUltra CTAB was achieved by ovendrying the as-received BioUltra B powder at 80 to 100 °C for 24 hours.…”

Cosolvent Effects on the Aggregation and Micellar Growth of Ester-Containing Gemini Surfactants

“…In addition to the cosolvent role of EG, it can act as structure-breaking solutes, which decrease the hydrophobic effect in the micellization process. This can be understood based on a decrease in the solvophobic effect caused by an increase in the solubility of hydrocarbon chains of the surfactants . Structural modification and solvent characteristic can optimize the micellization properties.…”

“…This can be understood based on a decrease in the solvophobic effect caused by an increase in the solubility of hydrocarbon chains of the surfactants. 20 Structural modification and solvent characteristic can optimize the micellization properties. This can be achieved in a variety of ways such as inserting the ester bond in the alkyl chains and altering the medium from aqueous to organic solvent.…”