1
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Kelkar PU, Kaboolian M, Corder RD, Caggioni M, Lindberg S, Erk KA. Effects of shear-induced crystallization on the complex viscosity of lamellar-structured concentrated surfactant solutions. SOFT MATTER 2024; 20:3299-3312. [PMID: 38529796 DOI: 10.1039/d3sm01198d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/27/2024]
Abstract
Material relationships at low temperatures were determined for concentrated surfactant solutions using a combination of rheological experiments, cross-polarized microscopy, calorimetry, and small angle X-ray scattering. A lamellar structured 70 wt% solution of sodium laureth sulfate in water was used as a model system. At cold temperatures (5 °C and 10 °C), the formation of surfactant crystals resulted in extremely high viscosity. The bulk flow behavior of multi-lamellar vesicles (20 °C) and focal conic defects (90 °C) in the lamellar phase was similar. Shear-induced crystallization at temperatures higher than the equilibrium crystallization temperature range resulted in an unusual complex viscosity peak. The effects of processing-relevant parameters including temperature, cooling time, and applied shear were investigated. Knowledge of key low-temperature structure-property-processing relationships for concentrated feedstocks is essential for the sustainable design and manufacturing of surfactant-based consumer products for applications such as cold-water laundry.
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Affiliation(s)
- Parth U Kelkar
- School of Materials Engineering, Purdue University, West Lafayette, IN, 47907, USA.
| | - Matthew Kaboolian
- School of Materials Engineering, Purdue University, West Lafayette, IN, 47907, USA.
| | - Ria D Corder
- School of Materials Engineering, Purdue University, West Lafayette, IN, 47907, USA.
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Marco Caggioni
- Corporate Engineering, The Procter & Gamble Company, West Chester, OH, 45069, USA
| | - Seth Lindberg
- Corporate Engineering, The Procter & Gamble Company, West Chester, OH, 45069, USA
| | - Kendra A Erk
- School of Materials Engineering, Purdue University, West Lafayette, IN, 47907, USA.
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2
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Fujii S, Henrich O. Shear-enhanced elasticity in the cubic blue phase I. Phys Rev E 2021; 103:052704. [PMID: 34134336 DOI: 10.1103/physreve.103.052704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 04/28/2021] [Indexed: 11/07/2022]
Abstract
We present results of the linear and nonlinear rheology of the cubic blue phase I (BPI). The elasticity of BPI is dominated by double-twist cylinders assembled in a body-centered cubic lattice, which can be specified by disclination lines. We find that the elasticity of BPI is enhanced by an order of magnitude by applying pre-shear. The shear-enhanced elasticity is attributed to a rearrangement of the disclination lines that are arrested in a metastable state. Our results are relevant for the understanding of the dynamics of disclinations in the cubic blue phases.
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Affiliation(s)
- Shuji Fujii
- Department of Food & Life Sciences, Toyo University, Tokyo 112-0001, Japan
| | - Oliver Henrich
- Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG, Scotland, United Kingdom
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3
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Kawabata Y, Bradbury R, Kugizaki S, Weigandt K, Melnichenko YB, Sadakane K, Yamada NL, Endo H, Nagao M, Seto H. Effect of interlamellar interactions on shear induced multilamellar vesicle formation. J Chem Phys 2017; 147:034905. [PMID: 28734290 DOI: 10.1063/1.4994563] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Shear-induced multilamellar vesicle (MLV) formation has been studied by coupling the small-angle neutron scattering (SANS) technique with neutron spin echo (NSE) spectroscopy. A 10% mass fraction of the nonionic surfactant pentaethylene glycol dodecyl ether (C12E5) in water was selected as a model system for studying weak inter-lamellar interactions. These interactions are controlled either by adding an anionic surfactant, sodium dodecyl sulfate, or an antagonistic salt, rubidium tetraphenylborate. Increasing the charge density in the bilayer induces an enhanced ordering of the lamellar structure. The charge density dependence of the membrane bending modulus was determined by NSE and showed an increasing trend with charge. This behavior is well explained by a classical theoretical model. By considering the Caillé parameters calculated from the SANS data, the layer compressibility modulus B¯ is estimated and the nature of the dominant inter-lamellar interaction is determined. Shear flow induces MLV formation around a shear rate of 10 s-1, when a small amount of charge is included in the membrane. The flow-induced layer undulations are in-phase between neighboring layers when the inter-lamellar interaction is sufficiently strong. Under these conditions, MLV formation can occur without significantly changing the inter-lamellar spacing. On the other hand, in the case of weak inter-lamellar interactions, the flow-induced undulations are not in-phase, and greater steric repulsion leads to an increase in the inter-lamellar spacing with shear rate. In this case, MLV formation occurs as the amplitude of the undulations gets larger and the steric interaction leads to in-phase undulations between neighboring membranes.
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Affiliation(s)
- Y Kawabata
- Department of Chemistry, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
| | - R Bradbury
- Center for Exploration of Energy and Matter, Department of Physics, Indiana University, Bloomington, Indiana 47408, USA
| | - S Kugizaki
- Department of Chemistry, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
| | - K Weigandt
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6102, USA
| | - Y B Melnichenko
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6393, USA
| | - K Sadakane
- Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto 610-0321, Japan
| | - N L Yamada
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tokai 319-1106, Japan
| | - H Endo
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tokai 319-1106, Japan
| | - M Nagao
- Center for Exploration of Energy and Matter, Department of Physics, Indiana University, Bloomington, Indiana 47408, USA
| | - H Seto
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tokai 319-1106, Japan
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4
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Morimoto D, Walinda E, Iwakawa N, Nishizawa M, Kawata Y, Yamamoto A, Shirakawa M, Scheler U, Sugase K. High-Sensitivity Rheo-NMR Spectroscopy for Protein Studies. Anal Chem 2017; 89:7286-7290. [PMID: 28665116 DOI: 10.1021/acs.analchem.7b01816] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Shear stress can induce structural deformation of proteins, which might result in aggregate formation. Rheo-NMR spectroscopy has the potential to monitor structural changes in proteins under shear stress at the atomic level; however, existing Rheo-NMR methodologies have insufficient sensitivity to probe protein structure and dynamics. Here we present a simple and versatile approach to Rheo-NMR, which maximizes sensitivity by using a spectrometer equipped with a cryogenic probe. As a result, the sensitivity of the instrument ranks highest among the Rheo-NMR spectrometers reported so far. We demonstrate that the newly developed Rheo-NMR instrument can acquire high-quality relaxation data for a protein under shear stress and can trace structural changes in a protein during fibril formation in real time. The described approach will facilitate rheological studies on protein structural deformation, thereby aiding a physical understanding of shear-induced amyloid fibril formation.
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Affiliation(s)
- Daichi Morimoto
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku Katsura , Nishikyo-ku, Kyoto 615-8510, Japan
| | - Erik Walinda
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Kyoto University, Yoshida Konoe-cho , Sakyo-ku, Kyoto 606-8501, Japan
| | - Naoto Iwakawa
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku Katsura , Nishikyo-ku, Kyoto 615-8510, Japan
| | - Mayu Nishizawa
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku Katsura , Nishikyo-ku, Kyoto 615-8510, Japan
| | - Yasushi Kawata
- Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University , 4-101 Koyama-cho Minami, Tottori 680-8552, Japan
| | - Akihiko Yamamoto
- Bruker BioSpin K.K. , 3-9 Moriya-cho, Kanagawa-ku, Yokohama, Kanagawa 221-0022, Japan
| | - Masahiro Shirakawa
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku Katsura , Nishikyo-ku, Kyoto 615-8510, Japan
| | - Ulrich Scheler
- Leibniz-Institut für Polymerforschung Dresden e.V. , Hohe Strasse 6, D-01069 Dresden, Germany
| | - Kenji Sugase
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku Katsura , Nishikyo-ku, Kyoto 615-8510, Japan
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5
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Fujii S, Yamamoto Y. Dynamic orientation transition of the lyotropic lamellar phase at high shear rates. SOFT MATTER 2015; 11:9330-9341. [PMID: 26430801 DOI: 10.1039/c5sm01755f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The dynamic orientation behavior of the lamellar phase of a triblock copolymer is studied in a wide range of shear rates as a function of solvent composition. We find that various phases can be induced by increasing the shear rate. At low shear rates, the onion phase forms from planar lamellae with many defects. A further increase of the shear rate caused the onion structure to break down, and the lamellar phase recovers with fewer defects. Finally, the transition of the orientation from parallel to perpendicular is observed at high shear rates. In the orientation transition at high shear rates, a stable intermediate structure, to our knowledge, is found for the first time. We also find that the critical shear stress of the rupture of the onion phase coincides with the orientation transition. The consistency of the critical shear stress suggests that all orientation transitions at a high shear rate are dominated by a mechanical balance between the applied viscous stress and the internal relaxation mode of the lamellae.
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Affiliation(s)
- Shuji Fujii
- Department of Materials Science and Technology, Nagaoka University of Technology, Nagaoka 940-2188, Japan.
| | - Yuki Yamamoto
- Department of Materials Science and Technology, Nagaoka University of Technology, Nagaoka 940-2188, Japan.
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6
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White KL, Wong M, Li P, Miyamoto M, Higaki Y, Takahara A, Sue HJ. Interlayer structure and self-healing in suspensions of brush-stabilized nanoplatelets with smectic order. SOFT MATTER 2015; 11:954-971. [PMID: 25519712 DOI: 10.1039/c4sm01855a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We have investigated the rheology of an uncured epoxy fluid containing high aspect ratio (length/thickness ≈ 160) α-zirconium phosphate (ZrP) nanoplatelets with smectic order. The nanoplatelets were exfoliated into monocrystalline sheets with uniform thickness using a monoamine-terminated oligomer. The oligomers were densely grafted to the plate surfaces and behave as a molecular brush. Suspensions containing ∼ 2 vol.% ZrP and above show liquid crystalline order with scattering peaks characteristic of a smectic (layered) mesophase. At much higher loading, ∼ 4 vol.% ZrP, there is a sharp transition in visual appearance, steady shear rheology, and linear and non-linear viscoelasticity that is attributed to the reversible interdigitation of oligomer chains between closely spaced layers. The oligomers are proposed to serve as inter-lamellar bridges that store elastic stresses for intermediate rates of deformation, but are able to relax on longer time scales. Under steady shearing conditions, the smectic suspensions with "overlapped" microstructure show a discontinuous flow curve characteristic of shear banding that is attributed to the dynamic pull-out of oligomer chains from the overlap region. At high shear rates, the limiting viscosity of the concentrated suspensions is on the same order of magnitude as the unfilled suspending fluid. When the rate of deformation is reduced below a critical time scale, the original network strength, and corresponding microstructure, is recovered through a passive self-healing process. The unique combination of concentration-dependent yield stress, low post-yield viscosity, and self-healing is potentially useful for various applications in the liquid state, and desirable for scalable processing of nanocomposite materials for structural applications.
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Affiliation(s)
- K L White
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, Fukuoka, 819-0395, Japan
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7
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Gentile L, Behrens MA, Balog S, Mortensen K, Ranieri GA, Olsson U. Dynamic Phase Diagram of a Nonionic Surfactant Lamellar Phase. J Phys Chem B 2014; 118:3622-9. [DOI: 10.1021/jp5009797] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Luigi Gentile
- Dipartimento
di Chimica e Tecnologie Chimiche, University of Calabria, P. Bucci
14C, 87036 Rende, Italy
- Division of Physical
Chemistry, Department of Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Manja A. Behrens
- Division of Physical
Chemistry, Department of Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Sandor Balog
- Laboratory
for Neutron
Scattering, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- Adolphe
Merkle
Institute, University of Fribourg, 1723 Marly 1, Switzerland
| | - Kell Mortensen
- Niels Bohr
Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Giuseppe A. Ranieri
- Dipartimento
di Chimica e Tecnologie Chimiche, University of Calabria, P. Bucci
14C, 87036 Rende, Italy
| | - Ulf Olsson
- Division of Physical
Chemistry, Department of Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
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8
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Shiba H, Noguchi H, Gompper G. Structure formation of surfactant membranes under shear flow. J Chem Phys 2014; 139:014702. [PMID: 23822315 DOI: 10.1063/1.4811239] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Shear-flow-induced structure formation in surfactant-water mixtures is investigated numerically using a meshless-membrane model in combination with a particle-based hydrodynamics simulation approach for the solvent. At low shear rates, uni-lamellar vesicles and planar lamellae structures are formed at small and large membrane volume fractions, respectively. At high shear rates, lamellar states exhibit an undulation instability, leading to rolled or cylindrical membrane shapes oriented in the flow direction. The spatial symmetry and structure factor of this rolled state agree with those of intermediate states during lamellar-to-onion transition measured by time-resolved scatting experiments. Structural evolution in time exhibits a moderate dependence on the initial condition.
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Affiliation(s)
- Hayato Shiba
- Institute for Solid State Physics, University of Tokyo, Chiba 277-8581, Japan.
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9
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Dou Y, Dong S, Hao J. Magnetic-field-induced orientational phase structure transition. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:1266-1271. [PMID: 24447257 DOI: 10.1021/la4047929] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Magnetic field effect on the phase transition at high temperature (from 50 °C) inside the magnetic field has been found in C14G2 (N-tetradecyllactobionamide)/C12EO4 (tetraethylene glycol monododecyl ether)/D2O system. The phase was transited quickly from lamellar phase to isotropic phases [bottom, micellar phase (L1 phase) and top, sponge phase (L3 phase)] induced by a magnetic field, which was demonstrated by (2)H NMR and FF-TEM measurements. The isotropic phases induced by magnetic field were not stable, and the upper L3 phase can recover to lamellar phase after being restored in a 55 °C thermostat outside the magnetic field for about one month. During the mechanism study, the C12EO4 molecule was proved to be the dominant component for the phase transition induced by the magnetic field, while the C14G2 molecule was the auxiliary and just affected the transition speed. The breaking and rebuilding of hydrogen bonds could play an important role in the phase transition and recovering. Moreover, the surfactant concentration had an effect on the speed of phase transiting and phase recovering. These observations could provide an understanding of the phase transition and also the applications for the controlled drug delivery system of bilayer membranes driving, induced by the magnetic field.
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Affiliation(s)
- Yingying Dou
- Key Laboratory of Colloid and Interface Chemistry and Key Laboratory of Special Aggregated Materials (Shandong University) , Ministry of Education, Jinan 250100, People's Republic of China
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10
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Dou Y, Long P, Dong S, Hao J. Spontaneous transformation of lamellar structures from simple to more complex states. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:12901-12908. [PMID: 24070426 DOI: 10.1021/la402993y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Spontaneous transformation of lamellar structures, such as multilamellar vesicles from micelles or unilamellar vesicles, is an important challenge in the field of amphiphile molecules, which may serve as models to understand biologically relevant bilayer membranes. Herein, we report a progressive self-assembly progress of N-tetradecyllactobionamide (C14G2) and tetraethylene glycol monododecyl ether (C12EO4) mixtures in aqueous solution. Increasing temperature or surfactant compositions causes spontaneous transformation from simple to high-level aggregates, i.e., from unilamellar vesicles, to coexisting multilamellar vesicles, terraced planar bilayers, and finally terraced planar bilayers. Deuterium nuclear magnetic resonance ((2)H NMR), freeze-fracture transmission electron microscopy (FF-TEM), and small-angle X-ray scattering (SAXS) measurements clearly demonstrate the spontaneously progressive self-assembly process. The interlamellar spacing (d) of the bilayers decreases from unilamellar vesicles to the terraced planar bilayers with an increase of the temperature or surfactant compositions. Lamellar samples consisting of terraced planar bilayers at higher temperature still show viscoelastic properties, being Bingham fluids, and both the viscoelasticity and yield stress increase with the composition and decrease with the temperature. The spontaneous transformation of the progressive self-assembly progress of C14G2 and C12EO4 aqueous mixtures is due to a balance of three driving forces, hydrophobic interactions, hydrogen bonding, and steric effects.
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Affiliation(s)
- Yingying Dou
- Key Laboratory of Colloid and Interface Chemistry and Key Laboratory of Special Aggregated Materials, Ministry of Education, Shandong University , Jinan, Shandong 250100, People's Republic of China
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Sato D, Obara K, Kawabata Y, Iwahashi M, Kato T. Re-entrant lamellar/onion transition with varying temperature under shear flow. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:121-132. [PMID: 23214993 DOI: 10.1021/la3041665] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We have found for the first time the reentrant lamellar/onion (lamellar-onion-lamellar) transition with varying temperature under constant shear rate by using simultaneous measurements of shear stress and small-angle X-ray scattering (Rheo-SAXS) for a nonionic surfactant (C(14)E(5))/water system, which exhibits the lamellar phase in a wide temperature range from 15-75 °C. The onion state exists in a closed region in the temperature-concentration diagram at a constant shear rate. Temperature dependence of the lamellar repeat distance (d) at rest has also been measured at several concentrations. It is shown that the increase of d with increasing temperature is necessary for the existence of the lower transition. We have investigated the change in the lamellar orientation in the lamellar-to-onion and onion-to-lamellar transition processes near the upper and lower transition temperatures. For all four kinds of transition processes, the following change in the lamellar orientation is observed; lamellar state (oriented to the velocity gradient direction) ↔ further enhancement of the orientation to the velocity gradient direction ↔ enhancement of the orientation to the neutral direction ↔ onion state.
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Affiliation(s)
- Daijiro Sato
- Department of Chemistry, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan
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12
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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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13
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Ito M, Kosaka Y, Kawabata Y, Kato T. Transition processes from the lamellar to the onion state with increasing temperature under shear flow in a nonionic surfactant/water system studied by Rheo-SAXS. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:7400-7409. [PMID: 21574584 DOI: 10.1021/la104826s] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In a previous paper, we reported for the first time the lamellar-to-onion transition with increasing temperature at around 67 °C under a constant shear rate (0.3-10 s(-1)) in a nonionic surfactant C(16)E(7)/water system. In this study, the first temperature-shear rate diagram has been constructed in a wider range of shear rate (0.05-30 s(-1)) than in our previous study based on the temperature dependence of the shear stress at constant shear rate. The results suggest that the critical temperature above which the transition begins does not depend on the shear rate very much, although it takes a very shallow minimum. Then we have performed simultaneous measurements of small-angle X-ray scattering/shear stress (rheo-SAXS) with a stepwise increase in temperature of 0.1 K per 15 min at a constant shear rate of 3 s(-1) near the transition temperature. When the temperature exceeds 67 °C, just before the increase in the shear stress, the intensity of the Bragg peak for the velocity gradient direction (approximately proportional to the number of lamellae with their normal along this direction) is suddenly increased. As the temperature increases by 0.2 K, the shear stress begins to increase. At the same time, the peak intensity in the velocity gradient direction rapidly decreases and instead the intensity in the neutral direction increases. As the temperature increases further, the intensities in both the neutral and gradient directions decrease whereas the intensity in the flow direction increases, corresponding to the formation of onions. We have also performed rheo-SAXS experiments with a stepwise increase in shear rate at 72 °C. The sequence of the change in the intensity in each direction is almost the same in the temperature scan experiments at constant shear rate, suggesting that the transition mechanisms along these two paths are similar. The abrupt enhancement of the lamellar orientation with the layer normal along the velocity gradient direction just before the transition is the first finding and strongly supports the coherent buckling mechanism in the lamellar-to-onion transition proposed by Zilman and Granek (Zilman, A. G.; Granek, R. Eur. Phys. J. B 1999, 11, 593).
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Affiliation(s)
- Makiko Ito
- Department of Chemistry, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan
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14
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Gentile L, Rossi CO, Olsson U, Ranieri GA. Effect of shear rates on the MLV formation and MLV stability region in the C12E5/D2O system: rheology and rheo-NMR and rheo-SANS experiments. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:2088-2092. [PMID: 21261313 DOI: 10.1021/la1046047] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
At high temperatures, pentaethylene glycol monododecyl ether (C12E5) in D2O forms a swollen lamellar phase. This letter reports the shear-induced multilamellar vesicle (MLV) formation in a sample that contains 40 wt % C12E5 dissolved in D2O at 55 °C. This transition has been investigated by time-resolved rheo-nuclear magnetic resonance, rheo small-angle neutron scattering, and rheometry. The typical transient viscosity behavior of MLV formation has been discovered at 1 s(-1). For the first time, it has been found that MLVs are not stable over time when subjected to high shear rates. Our results show that the MLV stability is confined in a narrow region in the range 1-10 s(-1) shear rates. This is not observed for other CnEm surfactants.
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Affiliation(s)
- Luigi Gentile
- Department of Chemistry, University of Calabria , P. Bucci 14C, 87036 Rende, Italy
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