Rafique, Aysha S, Khodaparast, Sepideh, Poulos, Andreas S, Sharratt, William N 
ORCID: 0000-0003-2148-8423, Robles, Eric SJ and Cabral, Joao T
(2020)
Micellar structure and transformations in sodium alkylbenzenesulfonate (NaLAS) aqueous solutions: effects of concentration, temperature, and salt
SOFT MATTER, 16 (33).
pp. 7835-7844.
ISSN 1744-683X, 1744-6848
Abstract
We investigate the shape, dimensions, and transformation pathways of micelles of linear sodium alkylbenzenesulfonate (NaLAS), a common anionic surfactant, in aqueous solution. Employing Small Angle Neutron Scattering (SANS) and surface tensiometry, we quantify the effects of surfactant concentration (0.6-15 wt%), temperature (5-40 °C) and added salt (≤0.35 M Na2SO4). Spherical micelles form at low NaLAS (≤2.6 wt%) concentration in water, and become elongated with increasing concentration and decreasing temperature. Addition of salt reduces the critical micelle concentration (CMC) and thus promotes the formation of micelles. At fixed NaLAS concentration, salt addition causes spherical micelles to grow into cylindrical micelles, and then multilamellar vesicles (MLVs), which we examine by SANS and cryo-TEM. Above a threshold salt concentration, the MLVs reach diameters of 100 s of nm to few μm, eventually causing precipitation. While the salt concentrations associated with the micelle-to-cylinder transformation increase only slightly with temperature, those required for the cylinder-to-MLV transformation exhibit a pronounced, linear temperature dependence, which we examine in detail. Our study establishes a solution structure map for this model anionic surfactant in water, quantifying the combined roles of concentration, temperature and salt, at practically relevant conditions. This journal is
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | 3403 Macromolecular and Materials Chemistry, 34 Chemical Sciences, 51 Physical Sciences |
| Divisions: | Faculty of Science & Engineering > School of Engineering |
| Depositing User: | Symplectic Admin |
| Date Deposited: | 25 Jul 2023 14:51 |
| Last Modified: | 16 Jun 2026 15:15 |
| DOI: | 10.1039/d0sm00982b |
| Open Access URL: | https://pubs.rsc.org/en/content/articlelanding/202... |
| Related Websites: | |
| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3171919 |
| Disclaimer: | The University of Liverpool is not responsible for content contained on other websites from links within repository metadata. Please contact us if you notice anything that appears incorrect or inappropriate. |
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