Thermodynamic Characterization of Temperature‐ and Composition‐Dependent Mixed Micelle Formation in Aqueous Medium

Abstract

This article provides a detailed description of micellization of a binary nonionic surfactant system (Lutensol AP9 and AP20) at different compositions and temperatures in an aqueous medium. Critical micelle concentrations of the individual components (CMCi) and the mixed surfactants (CMCm) were determined via surface tension measurements in the temperature range of 288.15–318.15 K. On the basis of the magnitude and temperature dependence of CMC values, changes in the Gibbs energy (ΔmicG), enthalpy (ΔmicH), and entropy (ΔmicS) of micellization were evaluated. At 288.15 K the thermodynamic parameters were confirmed by isotherm titration calorimetry (ITC). Regular solution theory (RST) was used to estimate the compositions of the mixed micelles (XM) and molecular interaction parameters (βM) for all molar ratios and temperatures. The results of evaluations based on the closed association model and RST were compared.

Synergistic Interaction and Aggregation Behavior in a Mixture of a Tripolar Zwitterionic Surfactant and an Anionic Surfactant

“…Thus, surfactant mixtures are commonly used in industrial applications and in pharmaceutical and medicinal formulations for the purpose of solubilization, suspension, and dispersion (Moulik et al, ; Sharma et al, ). In recent years, considerable research has been carried out on different combinations of mixed surfactant systems, including nonionic/nonionic (Ádám Juhász et al, ; Thomas et al, ), anionic/nonionic (Mahajan and Nandni, ), cationic/anionic (Schubert et al, ; Tian et al, ; Xu et al, ), cationic/cationic (Padasala et al, ; Tian et al, ), zwitterionic/anionic (Lu et al, ; Maneedaeng and Flood, ; Zhai et al, ), and zwitterionic/cationic (Abdel‐Rahem, ) surfactant systems. Normally, a stronger interaction between two surfactants leads to greater synergism in mixed surfactant systems (Holland and Rubingh, ).…”

Self‐Assembly of Polyethylene Glycol Ether Surfactants in Aqueous Solutions: The Effect of Linker between Alkyl and Ethoxylate

“…A Microcal ITC200 calorimeter (Malvern, Worcestershire, UK) was used to perform isothermal titration calorimetry (ITC) experiments (He et al, ; He and Alexandridis, ; Juhász et al, ). The sample cell was filled with deionized water and maintained at 20 °C.…”

“…A Microcal ITC200 calorimeter (Malvern, Worcestershire, UK) was used to perform isothermal titration calorimetry (ITC) experiments Juhász et al, 2017). The sample cell was filled with deionized water and maintained at 20 C. Aliquots (1.5 μL) of aqueous micellar surfactant solution were titrated into the sample cell at a fixed time interval while the syringe spun at 750 rpm.…”

Fluorescent Labeling of Hyaluronic Acid-Chitosan Nanocarriers by Protein-Stabilized Gold Nanoclusters

“…The six titrations were also investigated using DLS and Zeta potential measurements. The point of zero charge for every titration was calculated using non-linear regression method, using the six-parameter Boltzmann equation [32,33]:…”