Structure and dynamics of an aqueous solution containing poly-(acrylic acid) and non-ionic surfactant octaethylene glycol n-decyl ether (C10E8) aggregates and their complexes investigated by molecular dynamics simulations
| Autor: | Upendra Natarajan, Lakshmikumar Kunche |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Aqueous solution
Aggregation number Ethylene oxide 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Micelle 0104 chemical sciences chemistry.chemical_compound Lamellar phase chemistry Pulmonary surfactant Chemical engineering Lamellar structure 0210 nano-technology Ethylene glycol |
| Zdroj: | Soft Matter. 17:670-687 |
| ISSN: | 1744-6848 1744-683X |
| Popis: | A detailed molecular dynamics simulation study of the self-assembly, intermolecular structure and thermodynamic behavior of an aqueous solution of non-ionic surfactant octa ethylene glycol n-decyl ether (C10E8) in the presence of a non-ionic polar polymer poly(acrylic acid) PAA is presented. The aggregation number Nagg and concentration of surfactant Cs in the simulation systems were varied in the range 0.01–0.32 M and 5 < Nagg < 101 (dilute to concentrated) with a dilute polymer concentration (Cp = 0.01 M). Lamellar aggregates of non-ionic surfactant in bulk aqueous solution are shown by molecular level computations for the first time. Spherical micellar aggregates and lamellar aggregates are formed at low and high Nagg, respectively. The transition from the spherical micelle phase to the lamellar phase in a binary solution is captured for the first time. A conformational transition from coiled to extended PAA chains adsorbed on the surfactant aggregate occurs at a particular value of Nagg, commensurate with the transition from spherical micelle aggregates to anisotropic lamellar aggregates. Formation of the surfactant aggregate in binary and ternary solutions and the polymer–surfactant complex in a ternary solution is enthalpically favored. Adsorption of PAA on the surfactant aggregate surface is driven by hydrogen bonds (HBs) between carboxylic acid groups of PAA and ethylene oxide groups of C10E8. A significant number of HBs occur between polar oxygens of C10E8 and hydroxyl oxygens of PAA. The results are in agreement with the limited available experimental data on this system. |
| Databáze: | OpenAIRE |
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