Spontaneous formation of multilamellar vesicles from aqueous micellar solutions of sodium linear alkylbenzene sulfonate (NaLAS)

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:546

Article

Khodaparast, Sepideh¹  Sharratt, William¹  Wang, Haoyu¹  Robles, Eric S. J.²  Dalgliesh, Robert³  Cabral, Joao T.¹ 

[1] Imperial Coll London, Chem Engn Dept, London SW7 2AZ, England

[2] Procter & Gamble Co, Newcastle Innovat Ctr, Newcastle Upon Tyne NE12 9TS, Tyne & Wear, England

[3] Rutherford Appleton Lab, Sci & Technol Facil Council, ISIS Neutron & Muon Source, Didcot OX11 0QX, Oxon, England

关键词: Phase behaviour;    Surfactant;    Multilamellar vesicles;    Linear alkylbenzene sulfonate;    SANS;    Micelles;    Microfluidic;   

DOI  :  10.1016/j.jcis.2019.03.056

来源: Elsevier

【 摘 要 】

We report the spontaneous formation of multilamellar vesicles (MLVs) from low concentration (<30 wt%) aqueous micellar solutions of sodium linear alkylbenezene sulfonate (NaLAS) upon cooling, employing a combination of optical microscopy (OM), Small Angle Neutron Scattering (SANS), and Cryo-TEM. Upon cooling, MLVs grow from, and coexist with, the surfactant micelles, attaining diameters ranging from hundreds of nanometers to a few micrometers depending on the cooling rate, whilst the d-spacing of internal lamellae remains unchanged, at similar or equal to 3 nm. While microscale fluid and flow properties of the mixed MLVs and micellar phase depend on rate of cooling, the corresponding nanoscale structure of the surfactant aggregates, resolved by time-resolved SANS, remains unchanged. Our data indicate that the mixed MLV and micellar phases are in thermodynamic equilibrium with a fixed relative volume fraction determined by temperature and total surfactant concentration. Under flow, MLVs aggregate and consequently migrate away from the channel walls, thus reduce the overall hydrodynamic resistance. Our findings demonstrate that the molecular and mesoscopic structure of ubiquitous, low concentration NaLAS solutions, and in turn their flow properties, are dramatically influenced by temperature variation about ambient conditions. (C) 2019 Elsevier Inc. All rights reserved.

【 授权许可】

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