Aqueous Phase Behavior of a NaLAS–Polycarboxylate Polymer System
| Autor: | Olivier J. Cayre, Hossam Hassan Tantawy, Mamatha Nagaraj, Andrew E. Bayly, Mariam Hussain, Eric San Jose Robles |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Polarized light microscopy
Aqueous solution Small-angle X-ray scattering Chemistry Vesicle Analytical chemistry Aqueous two-phase system 02 engineering and technology Surfaces and Interfaces 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences 0104 chemical sciences Colloid Lamellar phase Electrochemistry General Materials Science Lamellar structure 0210 nano-technology Spectroscopy |
| Zdroj: | Langmuir. 37:5099-5108 |
| ISSN: | 1520-5827 0743-7463 |
| Popis: | Linear alkylbenzene sulfonate (NaLAS) surfactant is often combined with polycarboxylate polymers in detergent formulations. However, the behavior of these aqueous surfactant-polymer systems in the absence of an added electrolyte is unreported. This work investigates the behavior of such systems using polarized light microscopy, small-angle X-ray scattering (SAXS), centrifugation, and 2H NMR techniques. A phase diagram at 50 °C is reported for 0-50 wt % NaLAS concentrations and 0-10 wt % polycarboxylate concentrations. The NaLAS-water system is micellar at concentrations 20 wt % NaLAS), the addition of a polymer induces a second lamellar phase. These observed behaviors are thought to arise as a result of depletion flocculation and salting-out effects. The observed lamellar phases adopt colloidal multilamellar vesicle (MLV) structures, and the average MLV radii were estimated using 2H NMR by probing the diffusion and anisotropy of D2O within the bilayers of the vesicles. The NMR results show that as the polymer concentration was increased from 0 to 10 wt %, an increase in the average multilamellar vesicle size from ∼200 to ∼500 nm was observed. This increase in the calculated average MLV radius likely results from depletion flocculation-induced MLV fusion. |
| Databáze: | OpenAIRE |
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