Effect of salt on the lamellar L-alpha-to-MLV transformation in SDS/octanol/water under microfluidic flow
File(s)
Published version
Author(s)
Donina, Liva
Porcar, Lionel
Cabral, Joao T
Type
Journal Article
Abstract
We investigate the effect of added (NaCl) salt and varying flow rate on the phase behaviour and flow response of a model surfactant Lα phase, sodium dodecyl sulfate (SDS)/octanol/water, using small angle neutron scattering (SANS) and polarised optical microscopy in microfluidics, supported by NMR, viscosity, conductivity and zeta potential measurements. A long (∼3 m) tubular microchannel device is employed to quantify the spatiotemporal structural evolution of the system towards multilamellar vesicles (MLV). The effect of salt is rationalised in terms of changes in membrane bending rigidity and phase stability. It is shown that ∼1.8 w/w% NaCl addition results in MLV formation within the shortest time (or equivalent lengthscale) and yields near-centrosymmetric scattering profiles characteristic of MLVs (at a reference 1 mL h−1 flow rate and ≃90 s−1 shear rate). Further salt addition yields biphasic systems that remain strongly aligned under flow, while lower salt content also increases scattering anisotropy, accompanied by higher membrane rigidity and solution viscosity. Increasing flow rate causes greater initial Lα alignment, and thus flow anisotropy, but also faster evolution towards isotropy and MLV formation.
Date Issued
2022-07-25
Date Acceptance
2022-07-23
Citation
Soft Matter, 2022, 18 (37), pp.7010-7019
ISSN
1744-683X
Publisher
Royal Society of Chemistry
Start Page
7010
End Page
7019
Journal / Book Title
Soft Matter
Volume
18
Issue
37
Copyright Statement
© The Royal Society of Chemistry 2022. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
License URL
Sponsor
Royal Academy Of Engineering
Identifier
https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000834591300001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=a2bf6146997ec60c407a63945d4e92bb
Grant Number
RCSRF1920/10/60
Subjects
Chemistry
Chemistry, Physical
LIPID-BILAYERS
Materials Science
Materials Science, Multidisciplinary
MODULUS
MULTILAMELLAR VESICLES
PHASE
Physical Sciences
Physics
Physics, Multidisciplinary
Polymer Science
SCATTERING
Science & Technology
SHEAR
Technology
TRANSITION
UNDULATION INSTABILITY
VISCOSITY
X-RAY
Publication Status
Published
Date Publish Online
2022-07-25