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Donina L, Porcar L, Cabral JT. Composition and temperature effects on the solution structure of SDS/octanol/brine by SANS, NMR and microscopy. SOFT MATTER 2023; 19:8542-8551. [PMID: 37899739 DOI: 10.1039/d3sm01098h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2023]
Abstract
We investigate the solution structures of model sodium dodecyl sulfate/octanol/brine ternary mixtures across the lamellar (Lα), vesicle (L4) and micellar (L1) phases employing small angle neutron scattering (SANS), optical microscopy and nuclear magnetic resonance (NMR). Specifically, we examine the effect of co-surfactant octanol (0.2-9.48 w/v%) and temperature (25-65 °C) along dilution lines at fixed octanol : SDS ratios (0.08-1.21). A transition from Lα to sponge phase (L3) above 35 °C is found along the octanol : SDS = 1.21 isopleth, with phase coexistence above ϕ ≈ 0.14 weight fraction of surfactant and co-surfactant. The lamellar bilayers swell upon dilution, with an approximately linear increase of d-spacing, accompanied by a decrease of the Caillé parameter, indicative of greater membrane rigidity. At a lower octanol : SDS ratio of 0.62, coexistence of oblate micelles and vesicles is observed with preferential formation of vesicles at low concentrations. Dilution of the L1 phase, along octanol : SDS = 0.08, results in elongated micelles, as the NaCl : SDS ratio increases, while higher temperatures favour the formation of less elongated micelles. Our results provide a detailed map of the equilibrium structures found in the Lα vicinity of this extensively investigated flow-responsive surfactant system.
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Affiliation(s)
- Liva Donina
- Department of Chemical Engineering, Imperial College London, UK.
| | - Lionel Porcar
- Institut Laue-Langevin, 71 Avenue des Martyrs, B.P. 156, F-38042 Grenoble CEDEX, France
| | - João T Cabral
- Department of Chemical Engineering, Imperial College London, UK.
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Donina L, Rafique A, Khodaparast S, Porcar L, Cabral JT. Lamellar-to-MLV transformation in SDS/octanol/brine examined by microfluidic-SANS and polarised microscopy. SOFT MATTER 2021; 17:10053-10062. [PMID: 34713873 DOI: 10.1039/d1sm01215k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The lamellar-to-multilamellar vesicle (MLV) transformation in a model surfactant system, sodium dodecyl sulfate (SDS), octanol and brine, is investigated under continuous and oscillatory microfluidic contraction-expansion flows, employing polarised optical microscopy and small angle neutron scattering (SANS), with sample volume probed down to ≃20 nL. We determine the lamellar-to-MLV transition requirements at varying flow velocity, oscillation amplitude, frequency, and number of oscillatory cycles. The spatio-temporal evolution of the hierarchical fluid structure is elucidated: lamellar sheets initially align with flow direction upon entering a constriction and then perpendicularly upon exiting; the formation of MLVs at the nanoscale is first observed by SANS within a few (<5) oscillatory cycles, followed by the gradual appearance of a regular (albeit not crystalline) MLV arrangement, at the micronscale, by optical microscopy after tens of cycles, under the conditions investigated. Once MLVs form under flow, these remain metastable for several days.
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Affiliation(s)
- Liva Donina
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.
| | - Aysha Rafique
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.
| | - Sepideh Khodaparast
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.
| | - Lionel Porcar
- Institut Laue-Langevin, 71 Avenue des Martyrs, B.P. 156, F-38042 Grenoble CEDEX, France
| | - João T Cabral
- Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.
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Kuczera S, Gentile L, Brox TI, Olsson U, Schmidt C, Galvosas P. Multilamellar Vesicle Formation Probed by Rheo-NMR and Rheo-SALS under Large Amplitude Oscillatory Shear. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:8314-8325. [PMID: 29924625 DOI: 10.1021/acs.langmuir.8b01510] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The formation of multilamellar vesicles (MLVs) in the lyotropic lamellar phase of the system triethylene glycol mono n-decyl ether (C10E3)/water is investigated under large amplitude oscillatory shear (LAOS) using spatially resolved rheo-NMR spectroscopy and a combination of rheo-small angle light scattering (rheo-SALS) and conventional rheology. Recent advances in rheo-NMR hardware development facilitated the application of LAOS deformations in high-field NMR magnets. For the range of investigated strain amplitudes (10-50) and frequencies (1 and 2 rad s-1), MLV formation is observed in all NMR and most SALS experiments. It is found that the MLV size depends on the applied frequency in contrast to previous steady shear experiments where the shear rate is the controlling parameter. The onset of MLV formation, however, is found to vary with the shear amplitude. The LAOS measurements bear no indication of the intermediate structures resembling aligned multilamellar cylinders observed in steady shear experiments. Lissajous curves of stress vs strain reveal a transition from a viscoelastic solid material to a pseudoplastic material.
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Affiliation(s)
- Stefan Kuczera
- Victoria University of Wellington , SCPS, MacDiarmid Institute for Advanced Materials and Nanotechnology , Wellington 6140 , New Zealand
- Division of Physical Chemistry , Lund University , P.O. Box 124, 221 00 Lund , Sweden
| | - Luigi Gentile
- Division of Physical Chemistry , Lund University , P.O. Box 124, 221 00 Lund , Sweden
- Department of Biology, MEMEG unit , Lund University , Sölvegatan 35 , 223 62 Lund , Sweden
| | - Timothy I Brox
- Victoria University of Wellington , SCPS, MacDiarmid Institute for Advanced Materials and Nanotechnology , Wellington 6140 , New Zealand
| | - Ulf Olsson
- Division of Physical Chemistry , Lund University , P.O. Box 124, 221 00 Lund , Sweden
| | - Claudia Schmidt
- Department of Chemistry , Paderborn University , Warburger Strasse 100 , D-33098 Paderborn , Germany
| | - Petrik Galvosas
- Victoria University of Wellington , SCPS, MacDiarmid Institute for Advanced Materials and Nanotechnology , Wellington 6140 , New Zealand
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Medronho B, Olsson U, Schmidt C, Galvosas P. Transient and Steady-State Shear Banding in a Lamellar Phase as Studied by Rheo-NMR. ACTA ACUST UNITED AC 2012. [DOI: 10.1524/zpch.2012.0313] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract
Flow fields and shear-induced structures in the lamellar (L
α
) phase of the system triethylene glycol mono n-decyl ether (C10E3)/water were investigated by NMR velocimetry, diffusometry, and
2
H NMR spectroscopy. The transformation from multilamellar vesicles (MLVs) to aligned planar lamellae is accompanied by a transient gradient shear banding. A high-shear-rate band of aligned lamellae forms next to the moving inner wall of the cylindrical Couette shear cell while a low-shear-rate band of the initial MLV structure remains close to the outer stationary wall. The band of layers grows at the expense of the band of MLVs until the transformation is completed. This process scales with the applied strain. Wall slip is a characteristic of the MLV state, while aligned layers show no deviation from Newtonian flow. The homogeneous nature of the opposite transformation from well aligned layers to MLVs via an intermediate structure resembling undulated multilamellar cylinders is confirmed. The strain dependence of this transformation appears to be independent of temperature. The shear diagram, which represents the shear-induced structures as a function of temperature and shear rate, contains a transition region between stable layers and stable MLVs. The steady-state structures in the transition region show a continuous change from layer-like at high temperature to MLV-like at lower temperature. These structures are homogeneous on a length scale above a few micrometers.
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Affiliation(s)
- Bruno Medronho
- University of Algarve, Faculty of Sciences and Technology, Faro, Portugal
| | - Ulf Olsson
- Lund University, Physical Chemistry, Lund, Schweden
| | - Claudia Schmidt
- University of Paderborn, Faculty of Science, Paderborn, Deutschland
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Aslund I, Medronho B, Topgaard D, Söderman O, Schmidt C. Homogeneous length scale of shear-induced multilamellar vesicles studied by diffusion NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 209:291-299. [PMID: 21349752 DOI: 10.1016/j.jmr.2011.01.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2010] [Revised: 01/19/2011] [Accepted: 01/27/2011] [Indexed: 05/30/2023]
Abstract
A recently developed protocol for pulsed gradient spin echo (PGSE) NMR is applied for the size determination of multilamellar vesicles (MLVs). By monitoring the self-diffusion behavior of water, the technique yields an estimate of the homogeneous length scale λ(hom), i.e. the maximum length scale at which there is local structural heterogeneity in a globally homogeneous material. A cross-over between local non-Gaussian to global Gaussian diffusion is observed by varying the experimentally defined length- and time-scales. Occasional observation of a weak Bragg peak in the PGSE signal attenuation curves permits the direct estimation of the MLV radius in favorable cases, thus yielding the constant of proportionality between λ(hom) and radius. The microstructural origin of the Bragg peak is verified through Brownian dynamics simulations and a theoretical analysis based on the center-of-mass diffusion propagator. λ(hom) is decreasing with increasing shear rate in agreement with theoretical expectations and results from (2)H NMR lineshape analysis.
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Affiliation(s)
- Ingrid Aslund
- Physical Chemistry, Center of Chemistry and Chemical Engineering, Lund University, Lund, Sweden.
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de Silva JP, Poulos AS, Pansu B, Davidson P, Kasmi B, Petermann D, Asnacios S, Meneau F, Impéror M. Rheological behaviour of polyoxometalate-doped lyotropic lamellar phases. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2011; 34:4. [PMID: 21253807 DOI: 10.1140/epje/i2011-11004-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Accepted: 11/25/2010] [Indexed: 05/30/2023]
Abstract
We study the influence of nanoparticle doping on the lyotropic liquid crystalline phase of the industrial surfactant Brij®30 (C₁₂E₄) and water, doped with spherical polyoxometalate nanoparticles smaller than the characteristic dimensions of the host lamellar phase. We present viscometry and in situ rheology coupled with small-angle X-ray scattering data that show that, with increasing doping concentration, the nanoparticles act to decrease the shear viscosity of the lamellar phase, and that a shear-induced transition to a multilamellar vesicle "onion" phase is pushed to higher shear rates, and in some cases completely suppressed. X-ray data reveal that the nanoparticles remain encapsulated within the membranes of the vesicles, thus indicating a viable method for the fabrication of nanoparticle incorporating organic vesicles.
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Affiliation(s)
- J P de Silva
- Laboratoire de Physique des Solides-UMR 8502-Université Paris-Sud, F-91405, Orsay, France.
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