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Cho NH, Shi J, Murphy RP, Riley JK, Rogers SA, Richards JJ. Extracting microscopic insight from transient dielectric measurements during large amplitude oscillatory shear. SOFT MATTER 2023. [PMID: 37681714 DOI: 10.1039/d3sm00786c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/09/2023]
Abstract
Probing the transient microstructure of soft matter far from equilibrium is an ongoing challenge to understanding material processing. In this work, we investigate inverse worm-like micelles undergoing large amplitude oscillatory shear using time-resolved dielectric spectroscopy. By controlling the Weissenburg number, we compare the non-linear microstructure response of branched and unbranched worm-like micelles and isolate distinct elastic effects that manifest near flow reversal. We validate our dielectric measurements with small angle neutron scattering and employ sequence of physical processes to disentangle the elastic and viscous contributions of the stress.
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Affiliation(s)
- Noah H Cho
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL, USA.
| | - Jiachun Shi
- Department of Chemical and Biomolecular Engineering, University of Illinois of Urbana-Champaign, Urbana, Illinois, USA
| | - Ryan P Murphy
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, USA
| | - John K Riley
- Performance Materials Coatings, The Dow Chemical Company, Collegeville, Pennsylvania, USA
| | - Simon A Rogers
- Department of Chemical and Biomolecular Engineering, University of Illinois of Urbana-Champaign, Urbana, Illinois, USA
| | - Jeffrey J Richards
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL, USA.
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2
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Rüter A, Kuczera S, Gentile L, Olsson U. Arrested dynamics in a model peptide hydrogel system. SOFT MATTER 2020; 16:2642-2651. [PMID: 32119019 DOI: 10.1039/c9sm02244a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We report here on a peptide hydrogel system, which in contrast to most other such systems, is made up of relatively short fibrillar aggregates, discussing resemblance with colloidal rods. The synthetic model peptides A8K and A10K, where A denotes alanine and K lysine, self-assemble in aqueous solutions into ribbon-like aggregates having an average length 〈L〉 on the order of 100 nm and with a diameter d≈ 6 nm. The aggregates can be seen as weakly charged rigid rods and they undergo an isotropic to nematic phase transition at higher concentrations. Translational motion perpendicular to the rod axis gets strongly hindered when the concentration is increased above the overlap concentration. Similarly, the rotational motion is hindered, leading to very long stress relaxation times. The peptide self-assembly is driven by hydrophobic interactions and due to a net peptide charge the system is colloidally stable. However, at the same time short range, presumably hydrophobic, attractive interactions appear to affect the rheology of the system. Upon screening the long range electrostatic repulsion, with the addition of salt, the hydrophobic attraction becomes more dominant and we observe a transition from a repulsive glassy state to an attractive gel-state of the rod-like peptide aggregates.
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Affiliation(s)
- Axel Rüter
- Division of Physical Chemistry, Lund University, SE-22100 Lund, Sweden.
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Riley JK, Richards JJ, Wagner NJ, Butler PD. Branching and alignment in reverse worm-like micelles studied with simultaneous dielectric spectroscopy and RheoSANS. SOFT MATTER 2018; 14:5344-5355. [PMID: 29808890 DOI: 10.1039/c8sm00770e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Topology and branching play an important but poorly understood role in controlling the mechanical and flow properties of worm-like micelles (WLMs). To address the challenge of characterizing branching during flow of WLMs, dielectric spectroscopy, rheology, and small-angle neutron scattering (dielectric RheoSANS) experiments are performed simultaneously to measure the concurrent evolution of conductivity, permittivity, stress, and segmental anisotropy of reverse WLMs under steady-shear flow. Reverse WLMs are microemulsions comprised of the phospholipid surfactant lecithin dispersed in oil with water solubilized in the micelle core. Their electrical properties are independently sensitive to the WLM topology and dynamics. To isolate the effects of branching, dielectric RheoSANS is performed on WLMs in n-decane, which show fast breakage times and exhibit a continuous branching transition for water-to-surfactant ratios above the corresponding maximum in zero-shear viscosity. The unbranched WLMs in n-decane exhibit only subtle decreases in their electrical properties under flow that are driven by chain alignment and structural anisotropy in the plane perpendicular to the electric field and incident neutron beam. These results are in qualitative agreement with additional measurements on a purely linear WLM system in cyclohexane despite differences in breakage kinetics and a stronger tendency for the latter to shear band. In contrast, the branched micelles in n-decane (higher water content) undergo non-monotonic changes in permittivity and more pronounced decreases in conductivity under flow. The combined steady-shear electrical and microstructural measurements are capable, for the first time, of resolving branch breaking at low shear rates prior to alignment-driven anisotropy at higher shear rates.
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Affiliation(s)
- John K Riley
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6100, USA.
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Angelico R, Gentile L, Ranieri GA, Oliviero Rossi C. Flow-induced structures observed in a viscoelastic reverse wormlike micellar system by magnetic resonance imaging and NMR velocimetry. RSC Adv 2016. [DOI: 10.1039/c6ra00206d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Organogel formed by lecithin reverse wormlike micelles in the isotropic concentrated regime exhibits flow induced micro-heterogeneities detected by rheo-NMR and NMR-velocimetry.
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Affiliation(s)
- R. Angelico
- Department of Agricultural
- Environmental and Food Sciences (DIAAA)
- University of Molise
- I-86100 Campobasso (CB)
- Italy
| | - L. Gentile
- Department of Chemistry and Chemical Technologies
- University of Calabria
- I-87036 Arcavacata di Rende (CS)
- Italy
- Division of Physical Chemistry
| | - G. A. Ranieri
- Department of Chemistry and Chemical Technologies
- University of Calabria
- I-87036 Arcavacata di Rende (CS)
- Italy
| | - C. Oliviero Rossi
- Department of Chemistry and Chemical Technologies
- University of Calabria
- I-87036 Arcavacata di Rende (CS)
- Italy
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Fadda P, Monduzzi M, Caboi F, Piras S, Lazzari P. Solid lipid nanoparticle preparation by a warm microemulsion based process: Influence of microemulsion microstructure. Int J Pharm 2013; 446:166-75. [DOI: 10.1016/j.ijpharm.2013.02.027] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 02/08/2013] [Accepted: 02/09/2013] [Indexed: 10/27/2022]
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6
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Reis MFT, Bonomo RCF, de Souza AO, da Silva LHM, Veloso CM, Minim LA, Fontan RDCI. Calorimetric studies of microemulsion systems with lecithin, isooctane and butanol. Food Res Int 2012. [DOI: 10.1016/j.foodres.2012.08.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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7
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Angelico R, Rossi CO, Ambrosone L, Palazzo G, Mortensen K, Olsson U. Ordering fluctuations in a shear-banding wormlike micellar system. Phys Chem Chem Phys 2010; 12:8856-62. [DOI: 10.1039/b926152d] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Mu QS, Zhao XB, Lu JR, Armes SP, Lewis AL, Thomas RK. pH-Responsive Nanoaggregation of Diblock Phosphorylcholine Copolymers. J Phys Chem B 2008; 112:9652-9. [DOI: 10.1021/jp710365u] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Q. S. Mu
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Schuster Building, Oxford Road, Manchester M13 9PL, United Kingdom
| | - X. B. Zhao
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Schuster Building, Oxford Road, Manchester M13 9PL, United Kingdom
| | - J. R. Lu
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Schuster Building, Oxford Road, Manchester M13 9PL, United Kingdom
| | - S. P. Armes
- Department of Chemistry, The University of Sheffield, Sheffield S3 7HF, United Kingdom
| | - A. L. Lewis
- Biocompatibles UK Limited, Chapman House, Farnham Business Park, Weydon Lane, Farnham, Surrey GU9 8QL, United Kingdom
| | - R. K. Thomas
- Physical and Theoretical Chemistry Laboratory, The University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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Caboi F, Lazzari P, Pani L, Monduzzi M. Effect of 1-butanol on the microstructure of lecithin/water/tripalmitin system. Chem Phys Lipids 2005; 135:147-56. [PMID: 15921975 DOI: 10.1016/j.chemphyslip.2005.02.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2004] [Revised: 02/08/2005] [Accepted: 02/14/2005] [Indexed: 11/16/2022]
Abstract
Warm microemulsions based on lipids characterized by a melting point over 50 degrees C have been successfully used as starting matrix in a quenching process to obtain solid lipid nanoparticles (SLN). In this work, we have investigated the effect of 1-butanol (B) on the phase behavior of the lecithin (LCT)/water (W)/tripalmitin (TP) system at 70 degrees C. The study has been carried out at LCT/B=1 (weight ratio). Emulsion and liquid crystalline phase regions have been observed in the ternary phase diagram, while the presence of 1-butanol in the LCT/W/B/TP system allows the formation of a wide area of liquid isotropic phase from the whole (LCT+B)/TP binary axis up to 37 wt% of water. The microstructure of this isotropic phase has been investigated by means of 1H NMR PGSE technique. The self-diffusion coefficients of the different components along oil and water dilution lines indicate a microstructural organization characterized by a highly connected water in oil domains.
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Affiliation(s)
- Francesca Caboi
- Dipartimento Scienze Chimiche, CSGI Università di Cagliari, S.S. 554 Bivio Sestu, 09042 Monserrato, CA, Italy
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Liu L, John VT, McPherson G, Maskos K, Bose A. 31P and 1h NMR as probes of domain alignment in a rigid crystalline surfactant mesophase. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:3795-3801. [PMID: 15835939 DOI: 10.1021/la0477901] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A viscous reverse hexagonal surfactant mesophase containing bis(2-ethylhexyl) sodium sulfosuccinate (AOT) and alpha-phosphatidylcholine (lecithin), with comparable volume fractions of isooctane and water, was characterized by Fourier transform (31)P and (1)H NMR spectroscopy. Shear alignment was reflected through both (31)P NMR and (1)H NMR spectra. A complicated (31)P spectrum was observed as a result of superposition of chemical shifts according to the distribution of crystalline domains prior to shear. The initially disordered samples with polydomain structures become macroscopically aligned after Couette shear. (31)P NMR chemical shift anisotropy characteristics are used to elucidate orientation of the hexagonal phase. Interestingly, (1)H NMR spectra exhibit spectral changes upon shear alignment closely corresponding with that of (31)P NMR spectra. These observations complement the findings of mesophase alignment obtained using SANS and imply that (31)P and (1)H NMR spectroscopy can be used as probes to define microstructure and monitor orientation changes in this binary surfactant system. This is especially beneficial if these mesophases are used as templates for materials synthesis.
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Affiliation(s)
- Limin Liu
- Department of Chemical and Biomolecular Engineering and Department of Chemistry, Coordinated Instrumentation Facility, Tulane University, New Orleans, LA 70118, USA
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Singh M, Agarwal V, De Kee D, McPherson G, John V, Bose A. Shear-induced orientation of a rigid surfactant mesophase. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:5693-702. [PMID: 16459581 DOI: 10.1021/la049700y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
An optically clear, crystalline, gel-like mesophase is formed by the addition of water to a micellar solution consisting of a mixture of 0.85 M anionic surfactant sodium bis(2-ethylhexyl) sulfosuccinate (AOT) and a 0.42 M zwitterionic surfactant phosphatidylcholine (lecithin) in isooctane. At 25 degrees C and water to AOT molar ratio of 70, the system has a columnar hexagonal microstructure with randomly oriented domains. The shear-induced orientation and subsequent relaxation of this structure were investigated by rheological characterization and small-angle neutron scattering (SANS). The rheological response implies that the domains align under shear, and remain aligned for several hours after cessation of shear. Shear-SANS confirms this picture. The sheared gel mesophase retains its alignment as the temperature is increased to 57 degrees C, indicating the potential to conduct templated polymer and polymer-ceramic composite materials synthesis in aligned systems.
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Affiliation(s)
- Mohit Singh
- Department of Chemical Engineering, Tulane University, New Orleans, Louisiana 70118, USA
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Burger C, Hao J, Ying Q, Isobe H, Sawamura M, Nakamura E, Chu B. Multilayer vesicles and vesicle clusters formed by the fullerene-based surfactant C60(CH3)5K. J Colloid Interface Sci 2004; 275:632-41. [PMID: 15178297 DOI: 10.1016/j.jcis.2004.02.048] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2003] [Accepted: 02/23/2004] [Indexed: 11/17/2022]
Abstract
The self-assembly behavior of a fullerene-based surfactant, C60(CH3)5K, in water was studied using a combination of static and dynamic light scattering, as well as transmission electron microscopy, and compared to that of the compound C60(C6H5)5K. Both fullerene surfactant systems spontaneously assemble into large vesicles consisting of closed spherical shells formed by bilayers, with critical aggregation concentrations (CAC) lower than 10(-6) g ml(-1). At low concentrations, the aggregate sizes of C60(CH3)5K (radius R approximately 26.8 nm) and C60(C6H5)5K (R approximately 17.0 nm) were found to be substantially different from each other, showing that the change of the substituents surrounding the polar cyclopentadienide head group makes it possible to control the size of the resulting aggregates. Furthermore, the C60(CH3)5K vesicles were found to exist in two qualitatively different types of aggregation with a critical reaggregation concentration (CRC) located at 3.30 x 10(-6) g ml(-1). Above the CRC, larger aggregates were observed (R approximately 37.6 nm), showing a more complex form of supramolecular aggregation, e.g., in terms of multi-bilayer vesicles and/or of clusters of bilayer vesicles.
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Affiliation(s)
- Christian Burger
- Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400, USA
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Angelico R, Ceglie A, Colafemmina G, Delfine F, Olsson U, Palazzo G. Phase behavior of the lecithin/water/isooctane and lecithin/water/decane systems. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:619-631. [PMID: 15773084 DOI: 10.1021/la035603d] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The isothermal pseudo-ternary-phase diagram was determined at 25 degrees C for systems composed oflecithin, water, and, as oil, either isooctane or decane. This was accomplished by a combination of polarizing microscopy, small-angle X-ray scattering, and NMR techniques. The lecithin-rich region of the phase diagram is dominated by a lamellar liquid-crystalline phase (Lalpha). For lecithin contents less than 60% and low hydration (mole ratio water/lecithin = W0 < 5.5), the system forms a viscous gel of branched cylindrical reverse micelles. With increase in the water content, the system phase separates into two phases, which is either gel in equilibrium with essentially pure isooctane (for lecithin < 25%) or a gel in equilibrium with Lalpha (for lecithin > 25%). These two-phase regions are very thin with respect to water dilution. For 8 < W0 < 54 very stable water-in-oil emulsions form. It is only after ripening for more than 1 year that the large region occupied by the emulsion reveals a complex pattern of stable phases. Moving along water dilution lines, one finds (i) the coexistence of gel, isooctane and Lalpha, (ii) equilibrium between reverse micelles and spherulites, and, finally, (iii) disconnected reverse micelles that fail to solubilize water for W0 > 54. This results in a Winsor II phase equilibrium at low lecithin content, while for lecithin > 20% the neat water is in equilibrium with a reverse hexagonal phase and an isotropic liquid-crystalline phase. The use of the decane as oil does not change the main features of the phase behavior.
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Affiliation(s)
- Ruggero Angelico
- DISTAAM, Università del Molise, v. De Sanctis, 1-861 00 Campobasso, Italy
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Angelico R, Burgemeister D, Ceglie A, Olsson U, Palazzo G, Schmidt C. Deuterium NMR Study of Slow Relaxation Dynamics in a Polymer-like Micelles System after Flow-Induced Orientation. J Phys Chem B 2003. [DOI: 10.1021/jp0356259] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- R. Angelico
- Consorzio per lo sviluppo dei Sistemi a Grande Interfase (CSGI) c/o Università del Molise (DISTAAM), via De Sanctis, I-86100 Campobasso, Italy, Institut für Makromolekulare Chemie, Universität Freiburg, Stefan-Meier-Strasse 31, D-79104 Freiburg, Germany, Physical Chemistry 1, Center for Chemistry and Chemical Engineering, Lund University, P.O.Box 124, S-22100 Lund, Sweden, Dipartimento di Chimica, Università di Bari, via Orabona 4, I-70126 Bari, Italy, and Fakultät für Naturwissenschaften, Department
| | - D. Burgemeister
- Consorzio per lo sviluppo dei Sistemi a Grande Interfase (CSGI) c/o Università del Molise (DISTAAM), via De Sanctis, I-86100 Campobasso, Italy, Institut für Makromolekulare Chemie, Universität Freiburg, Stefan-Meier-Strasse 31, D-79104 Freiburg, Germany, Physical Chemistry 1, Center for Chemistry and Chemical Engineering, Lund University, P.O.Box 124, S-22100 Lund, Sweden, Dipartimento di Chimica, Università di Bari, via Orabona 4, I-70126 Bari, Italy, and Fakultät für Naturwissenschaften, Department
| | - A. Ceglie
- Consorzio per lo sviluppo dei Sistemi a Grande Interfase (CSGI) c/o Università del Molise (DISTAAM), via De Sanctis, I-86100 Campobasso, Italy, Institut für Makromolekulare Chemie, Universität Freiburg, Stefan-Meier-Strasse 31, D-79104 Freiburg, Germany, Physical Chemistry 1, Center for Chemistry and Chemical Engineering, Lund University, P.O.Box 124, S-22100 Lund, Sweden, Dipartimento di Chimica, Università di Bari, via Orabona 4, I-70126 Bari, Italy, and Fakultät für Naturwissenschaften, Department
| | - U. Olsson
- Consorzio per lo sviluppo dei Sistemi a Grande Interfase (CSGI) c/o Università del Molise (DISTAAM), via De Sanctis, I-86100 Campobasso, Italy, Institut für Makromolekulare Chemie, Universität Freiburg, Stefan-Meier-Strasse 31, D-79104 Freiburg, Germany, Physical Chemistry 1, Center for Chemistry and Chemical Engineering, Lund University, P.O.Box 124, S-22100 Lund, Sweden, Dipartimento di Chimica, Università di Bari, via Orabona 4, I-70126 Bari, Italy, and Fakultät für Naturwissenschaften, Department
| | - G. Palazzo
- Consorzio per lo sviluppo dei Sistemi a Grande Interfase (CSGI) c/o Università del Molise (DISTAAM), via De Sanctis, I-86100 Campobasso, Italy, Institut für Makromolekulare Chemie, Universität Freiburg, Stefan-Meier-Strasse 31, D-79104 Freiburg, Germany, Physical Chemistry 1, Center for Chemistry and Chemical Engineering, Lund University, P.O.Box 124, S-22100 Lund, Sweden, Dipartimento di Chimica, Università di Bari, via Orabona 4, I-70126 Bari, Italy, and Fakultät für Naturwissenschaften, Department
| | - C. Schmidt
- Consorzio per lo sviluppo dei Sistemi a Grande Interfase (CSGI) c/o Università del Molise (DISTAAM), via De Sanctis, I-86100 Campobasso, Italy, Institut für Makromolekulare Chemie, Universität Freiburg, Stefan-Meier-Strasse 31, D-79104 Freiburg, Germany, Physical Chemistry 1, Center for Chemistry and Chemical Engineering, Lund University, P.O.Box 124, S-22100 Lund, Sweden, Dipartimento di Chimica, Università di Bari, via Orabona 4, I-70126 Bari, Italy, and Fakultät für Naturwissenschaften, Department
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Pflaumbaum M, Rehage H. Myristyl dimethylamine oxide surfactant solutions: model systems for rheological research. Chemphyschem 2003; 4:705-13. [PMID: 12901302 DOI: 10.1002/cphc.200200585] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Aqueous surfactant solutions of entangled, rod-shaped micelles are often characterized by monoexponential stress-relaxation processes. This special phenomenon leads to relatively simple theoretical descriptions, and viscoelastic surfactant solutions can, therefore, also be used as simple model systems for studying fundamental principles of flow. Herein, we present a detailed study of the nonlinear rheological properties of aqueous myristyl dimethylamine oxide surfactant solutions. In the regime of small deformations, shear stresses, or shear rates, the dynamic features of the viscoelastic solutions are characterized by the simple equations of a Maxwell material. At elevated values of shear stresses or deformations, however, this simple model fails and nonlinear features, such as normal stresses, stress overshoots, or shear-thinning properties occur. All these phenomena can be described by a Maxwell-type differential constitutive equation, which was first proposed by Giesekus. It turns out that the experimental results are in fairly good agreement with the theoretical predictions, if the anisotropy factor alpha is equal to 0.5. Besides transient data and nonlinear steady-state measurements, many semiempirical laws, such as the Cox-Merz rule, the Yamamoto relation, the Laun equation, and the Gleissble mirror relationships are approximately satisfied. The dynamic properties discussed in this paper are of general importance and they are equally observed in different materials such as polymer, dye, or protein solutions.
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Affiliation(s)
- Manuela Pflaumbaum
- Institute of Physical Chemistry, University of Duisburg-Essen, Universitätsstr. 3-5, 45127 Essen, Germany
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