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Shelukhin V. Flows of Linear Polymer Solutions and Other Suspensions of Rod-like Particles: Anisotropic Micropolar-Fluid Theory Approach. Polymers (Basel) 2021; 13:polym13213679. [PMID: 34771236 PMCID: PMC8588494 DOI: 10.3390/polym13213679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/15/2021] [Accepted: 10/16/2021] [Indexed: 12/05/2022] Open
Abstract
We formulate equations governing flows of suspensions of rod-like particles. Such suspensions include linear polymer solutions, FD-virus, and worm-like micelles. To take into account the particles that form and their rotation, we treat the suspension as a Cosserat continuum and apply the theory of micropolar fluids. Anisotropy of suspensions is determined through the inclusion of the microinertia tensor in the rheological constitutive equations. We check that the model is consistent with the basic principles of thermodynamics. In addition to anisotropy, the theory also captures gradient banding instability, coexistence of isotropic and nematic phases, sustained temporal oscillations of macroscopic viscosity, shear thinning and hysteresis. For the flow between two planes, we also establish that the total flow rate depends not only on the pressure gradient, but on the history of its variation as well.
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Affiliation(s)
- Vladimir Shelukhin
- Lavrentyev Institute of Hydrodynamics, 630090 Novosibirsk, Russia;
- Mathematical Department, Novosibirsk State University, 630090 Novosibirsk, Russia
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Affiliation(s)
- Christian Lang
- Jülich Centre for Neutron Science, Forschungszentrum Jülich, Garching 85748, Germany
| | - Minne Paul Lettinga
- Institute for Complex Systems 3, Forschungszentrum Jülich, Jülich D-52425, Germany
- Laboratory of Soft Matter and Biophysics, KU Leuven, Leuven 3000, Belgium
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Lang C, Kohlbrecher J, Porcar L, Radulescu A, Sellinghoff K, Dhont JKG, Lettinga MP. Microstructural Understanding of the Length- and Stiffness-Dependent Shear Thinning in Semidilute Colloidal Rods. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b01592] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
| | - Joachim Kohlbrecher
- Laboratory of Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen 5232, Switzerland
| | | | | | | | - Jan Karel George Dhont
- Experimental Physics of Soft Matter, Heinrich Heine Universität Düsseldorf, 40225 Düsseldorf, Germany
| | - Minne Paul Lettinga
- Laboratory of Soft Matter and Biophysics, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
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5
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The Thermoviscosifying Behavior of Water-Soluble Polymer Based on Graft Polymerization of Pluronic F127 with Acrylamide and 2-Acrylamido-2-methylpropane Sulfonic Acid Sodium Salt. Polymers (Basel) 2019; 11:polym11101702. [PMID: 31623270 PMCID: PMC6835222 DOI: 10.3390/polym11101702] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 10/10/2019] [Accepted: 10/14/2019] [Indexed: 12/04/2022] Open
Abstract
A new concept of thermoviscosifying polymers is proposed to address the problems about decreasing viscosity of polymer solution under high temperatures. However, existing thermoviscosifying polymers have complicated synthesis processes and high costs, and both of them restrict the wide practical applications of thermoviscosifying polymers. Although polyethers have the characteristics of thermal gelatinization, they just display thermoviscosifying behaviors only under extremely high concentrations (>15 wt %). Therefore, the graft copolymerization of the commercialized Pluronic F127 (PEO100-PPO65-PEO100) with acrylamide and 2-acrylamide-methylpropionic acid sodium salt was studied here. A series of graft modified polyether polymers were prepared and it was expected to get thermoviscosifying polymers with high molecular weights and low association temperatures. Several factors on thermoviscosifying behaviors were investigated, such as polymerization condition, polymer concentration, hydrophilic monomer, molecular structure and molecular weight. It was also proven that the apparent viscosity of polymer solution is influenced by polymer concentration, molecular weight of polymer, and content of anion groups.
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Structure and rheology of aqueous suspensions and hydrogels of cellulose nanofibrils: Effect of volume fraction and ionic strength. Carbohydr Polym 2019; 211:315-321. [DOI: 10.1016/j.carbpol.2019.01.099] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 01/28/2019] [Accepted: 01/28/2019] [Indexed: 11/18/2022]
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Lang C, Hendricks J, Zhang Z, Reddy NK, Rothstein JP, Lettinga MP, Vermant J, Clasen C. Effects of particle stiffness on the extensional rheology of model rod-like nanoparticle suspensions. SOFT MATTER 2019; 15:833-841. [PMID: 30488939 DOI: 10.1039/c8sm01925h] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The linear and nonlinear rheological behavior of two rod-like particle suspensions as a function of concentration is studied using small amplitude oscillatory shear, steady shear and capillary breakup extensional rheometry. The rod-like suspensions are composed of fd virus and its mutant fdY21M, which are perfectly monodisperse, with a length on the order of 900 nm. The particles are semiflexible yet differ in their persistence length. The effect of stiffness on the rheological behavior in both, shear and extensional flow, is investigated experimentally. The linear viscoelastic shear data is compared in detail with theoretical predictions for worm-like chains. The extensional properties are compared to Batchelor's theory, generalized for the shear thinning nature of the suspensions. Theoretical predictions agree well with the measured complex moduli at low concentrations as well as the nonlinear shear and elongational viscosities at high flow rates. The results in this work provide guidelines for enhancing the elongational viscosity based on purely frictional effects in the absence of strong normal forces which are characteristic for high molecular weight polymers.
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Affiliation(s)
- Christian Lang
- Institute of Complex Systems-3, Forschungszentrum Jülich, 52428 Jülich, Germany.
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8
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Tassieri M. Dynamics of Semiflexible Polymer Solutions in the Tightly Entangled Concentration Regime. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b01024] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Manlio Tassieri
- Division of Biomedical Engineering,
School of Engineering, University of Glasgow, Glasgow G12 8LT, U.K
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9
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Lang C, Kohlbrecher J, Porcar L, Lettinga MP. The Connection between Biaxial Orientation and Shear Thinning for Quasi-Ideal Rods. Polymers (Basel) 2016; 8:E291. [PMID: 30974567 PMCID: PMC6432483 DOI: 10.3390/polym8080291] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 08/01/2016] [Accepted: 08/02/2016] [Indexed: 11/16/2022] Open
Abstract
The complete orientational ordering tensor of quasi-ideal colloidal rods is obtained as a function of shear rate by performing rheo-SANS (rheology with small angle neutron scattering) measurements on isotropic fd-virus suspensions in the two relevant scattering planes, the flow-gradient (1-2) and the flow-vorticity (1-3) plane. Microscopic ordering can be identified as the origin of the observed shear thinning. A qualitative description of the rheological response by Smoluchowski, as well as Doi⁻Edwards⁻Kuzuu theory is possible, as we obtain a master curve for different concentrations, scaling the shear rate with the apparent collective rotational diffusion coefficient. However, the observation suggests that the interdependence of ordering and shear thinning at small shear rates is stronger than predicted. The extracted zero-shear viscosity matches the concentration dependence of the self-diffusion of rods in semi-dilute solutions, while the director tilts close towards the flow direction already at very low shear rates. In contrast, we observe a smaller dependence on the shear rate in the overall ordering at high shear rates, as well as an ever-increasing biaxiality.
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Affiliation(s)
- Christian Lang
- ICS-3, Institut für Weiche Materie, Forschungszentrum Jülich, D-52425 Jülich, Germany.
| | - Joachim Kohlbrecher
- Laboratory of Neutron Scattering and Imaging, Paul Scherrer Institute, 5232 Villigen, Switzerland.
| | - Lionel Porcar
- Institut Laue-Langevin, CS 20156, 38042 Grenoble Cedex 9, France.
| | - Minne Paul Lettinga
- ICS-3, Institut für Weiche Materie, Forschungszentrum Jülich, D-52425 Jülich, Germany.
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10
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Wang H, Wang X, Li T, Lee B. Transient viscoelasticity study of tobacco mosaic virus/Ba(2+) superlattice. NANOSCALE RESEARCH LETTERS 2014; 9:300. [PMID: 24994956 PMCID: PMC4067107 DOI: 10.1186/1556-276x-9-300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 06/06/2014] [Indexed: 06/03/2023]
Abstract
Recently, we reported a new method to synthesize the rod-like tobacco mosaic virus (TMV) superlattice. To explore its potentials in nanolattice templating and tissue scaffolding, this work focused the viscoelasticity of the superlattice with a novel transient method via atomic force microscopy (AFM). For measuring viscoelasticity, in contrast to previous methods that assessed the oscillating response, the method proposed in this work enabled us to determine the transient response (creep or relaxation) of micro/nanobiomaterials. The mathematical model and numerical process were elaborated to extract the viscoelastic properties from the indentation data. The adhesion between the AFM tip and the sample was included in the indentation model. Through the functional equation method, the elastic solution for the indentation model was extended to the viscoelastic solution so that the time dependent force vs. displacement relation could be attained. To simplify the solving of the differential equation, a standard solid model was modified to obtain the elastic and viscoelastic components of the sample. The viscoelastic responses with different mechanical stimuli and the dynamic properties were also investigated.
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Affiliation(s)
- Haoran Wang
- Department of Mechanical Engineering, North Dakota State University, Fargo ND 58108, USA
| | - Xinnan Wang
- Department of Mechanical Engineering, North Dakota State University, Fargo ND 58108, USA
| | - Tao Li
- X-ray Science Division, Advanced Photon Source of Argonne National Laboratory, 9700 S. Cass Avenue, Argonne IL 60439, USA
| | - Byeongdu Lee
- X-ray Science Division, Advanced Photon Source of Argonne National Laboratory, 9700 S. Cass Avenue, Argonne IL 60439, USA
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11
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Hernández-Contreras M. Translational and rotational dynamics of colloidal particles in suspension: effect of shear. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:022317. [PMID: 24032842 DOI: 10.1103/physreve.88.022317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 06/28/2013] [Indexed: 06/02/2023]
Abstract
We report a generalization of a nonequilibrium thermodynamic theory for the mesoscopic dynamics of radially symmetric interacting particles to anisotropic pairwise interactions and attain the one- and two-particle Fokker-Planck kinetics equations at a low-density limit that provides the translational-rotational coupling of their motion due to hydrodynamic interactions, from which we derived the balance equations of linear, angular momentum, and energy dissipation due to particle interactions and energy interchange with heat bath. In this low-density approximation, an already-known virial expression for the long-time translational collective diffusion coefficient of an orientational isotropic suspension in terms of the fluid equilibrium microstructure is recovered. An external shear flow induces, in the diffusive regime, vorticity effects into the rotational diffusion property of the colloidal particles. They manifest in the appearance of the particle's rotational viscosity due to vortex flow. The Smoluchowski equation that governs the dynamical relaxation of colloid microstructure due to particle's Brownian motion under stationary flow is provided.
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Affiliation(s)
- M Hernández-Contreras
- Departamento de Física, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional Apartado Postal 14-740, México Distrito Federal, México
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12
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Guu D, Dhont JKG, Vliegenthart GA, Lettinga MP. Depletion induced clustering in mixtures of colloidal spheres and fd-virus. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:464101. [PMID: 23114036 DOI: 10.1088/0953-8984/24/46/464101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We determined the phase boundary of an ideal rod-sphere mixture consisting of fd-virus, which is an established model system for mono-disperse colloidal rods, and density matched mono-disperse polystyrene beads employing diffuse wave spectroscopy. The low volume fraction of fd needed to induce a phase separation at relatively low ionic strength exemplifies the fact that slender rods are very effective depletion agents. Confocal microscopy showed that stable clusters are formed during phase separation. Relaxation after shear deformation of these clusters showed that the phase separation is gas-liquid-like and that the interfacial tension involved is very low as in colloid-polymer mixtures.
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Affiliation(s)
- D Guu
- Institute of Complex Systems, Forschungszentrum Jülich, D-52425 Jülich, Germany
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13
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Sarmiento-Gomez E, Montalvan-Sorrosa D, Garza C, Mas-Oliva J, Castillo R. Rheology and DWS microrheology of concentrated suspensions of the semiflexible filamentous fd virus. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2012; 35:35. [PMID: 22610819 DOI: 10.1140/epje/i2012-12035-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Accepted: 05/02/2012] [Indexed: 06/01/2023]
Abstract
Microrheology measurements were performed on suspensions of bacteriophage fd with diffusive wave spectroscopy in the concentrated regime, at different values of ionic strength. Viscosity vs. shear rate was also measured, and the effect of bacteriophage concentration and salt addition on shear thinning was determined, as well as on the peaks in the viscosity vs. shear curves corresponding to a transition from tumbling to wagging flow. The influence of concentration and salt addition on the mean square displacement of microspheres embedded in the suspensions was determined, as well as on their viscoelastic moduli up to high angular frequencies. Our results were compared with another microrheology technique previously reported where the power spectral density of thermal fluctuations of embedded micron-sized particles was evaluated. Although both results in general agree, the diffusive wave spectroscopy results are much less noisy and can reach larger frequencies. A comparison was made between measured and calculated shear modulus. Calculations were made employing the theory for highly entangled isotropic solutions of semiflexible polymers using a tube model, where various ways of calculating the needed parameters were used. Although some features are captured by the model, it is far from the experimental results mainly at high frequencies.
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Affiliation(s)
- E Sarmiento-Gomez
- Instituto de Fisica, Universidad Nacional Autónoma de Mexico, P. O. Box 20-364, Mexico DF 01000
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Pamies R, Hernández Cifre JG, del Carmen López Martínez M, García de la Torre J. Determination of intrinsic viscosities of macromolecules and nanoparticles. Comparison of single-point and dilution procedures. Colloid Polym Sci 2008. [DOI: 10.1007/s00396-008-1902-2] [Citation(s) in RCA: 167] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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15
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Holmqvist P, Kleshchanok D, Lang PR. Interaction potential and near wall dynamics of spherical colloids in suspensions of rod-like fd-virus. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2008; 26:177-182. [PMID: 18427726 DOI: 10.1140/epje/i2007-10288-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2007] [Accepted: 02/06/2008] [Indexed: 05/26/2023]
Abstract
Averaged diffusivities of spherical colloids in solutions of rod-like particles, i.e. fd-virus, were measured with EWDLS and TIRM. While the experimentally observed near wall dynamics of the spheres in the absence of fd are well described by standard hydrodynamic theories, there are significant deviations at finite fd concentrations. Both experimental methods yield data which are significantly smaller than the theoretical predictions.
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Affiliation(s)
- P Holmqvist
- Institut für Festkörperforschung, Forschungszentrum Jülich, Jülich, Germany
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16
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Lin YC, Koenderink GH, MacKintosh FC, Weitz DA. Viscoelastic Properties of Microtubule Networks. Macromolecules 2007. [DOI: 10.1021/ma070862l] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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17
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Kang K, Wilk A, Patkowski A, Dhont JKG. Diffusion of spheres in isotropic and nematic networks of rods: electrostatic interactions and hydrodynamic screening. J Chem Phys 2007; 126:214501. [PMID: 17567202 DOI: 10.1063/1.2737446] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Translational diffusion of a small charged tracer sphere in isotropic and nematic suspensions of long and thin charged rods is investigated as a function of ionic strength and rod concentration. A theory for the diffusive properties of a small sphere is developed, where both (screened) hydrodynamic interactions and charge interactions between the tracer sphere and the rod network are analyzed. Hydrodynamic interactions are formulated in terms of the hydrodynamic screening length. As yet, there are no independent theoretical predictions for the hydrodynamic screening length for rod networks. Experimental tracer-diffusion data are presented for various ionic strengths as a function of the rod concentration, both in the isotropic and nematic states. Orientational order parameters are measured for the same ionic strengths as a function of the rod concentration. The hydrodynamic screening length is determined from these experimental data and scaling relations obtained from the above mentioned theory. For the isotropic networks, a master curve is found for the hydrodynamic screening length as a function of the rod concentration. For the nematic networks the screening length turns out to be a very sensitive function of the orientational order parameter.
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Affiliation(s)
- Kyongok Kang
- Forschungszentrum Jülich, Institute für Festkörper Forschung (IFF), Weiche Materie, D-52425 Jülich, Germany
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18
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Tao YG, den Otter WK, Briels WJ. Shear Viscosities and Normal Stress Differences of Rigid Liquid-Crystalline Polymers. Macromolecules 2006. [DOI: 10.1021/ma060622q] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yu-Guo Tao
- Computational Biophysics, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - W. K. den Otter
- Computational Biophysics, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - W. J. Briels
- Computational Biophysics, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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Kang K, Wilk A, Buitenhuis J, Patkowski A, Dhont JKG. Diffusion of spheres in isotropic and nematic suspensions of rods. J Chem Phys 2006; 124:044907. [PMID: 16460212 DOI: 10.1063/1.2161204] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Diffusion of a small tracer sphere (apoferritin) in isotropic and nematic networks [of fd virus] is discussed. For a tracer sphere that is smaller than the mesh size of the network, screened hydrodynamic interactions between the sphere and the network determine its diffusion coefficient. A theory is developed for such interactions as well as their relation to the long-time self-diffusion coefficient. Fluorescence correlation spectroscopy measurements on mixtures of apoferritin and fd virus are presented. The long-time self-diffusion coefficient of apoferritin is measured as a function of the fd-virus concentration, both in the isotropic and nematic state, in directions parallel and perpendicular to the nematic director. The hydrodynamic screening length of the fd-virus network as a function of fd concentration is obtained by combining these experimental data with the theory. Surprisingly, the screening length increases with increasing concentration in nematic networks. This is due to the increase in the degree of alignment, which apparently leads to a strong increase of the screening length. Hydrodynamic screening is thus strongly diminished by alignment. A self-consistent calculation of the screening length does not work at higher concentrations, probably due to the strong variation of the typical incident flow fields over the contour of a rod.
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Affiliation(s)
- Kyongok Kang
- Forschungszentrum Jülich, Institute für Festkörper Forschung, Weiche Materie, D-52425 Julich, Germany
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Lettinga MP, Dogic Z, Wang H, Vermant J. Flow behavior of colloidal rodlike viruses in the nematic phase. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:8048-57. [PMID: 16089419 DOI: 10.1021/la050116e] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The behavior of a colloidal suspension of rodlike fd viruses in the nematic phase, subjected to steady state and transient shear flows, is studied. The monodisperse nature of these rods combined with relatively small textural contribution to the overall stress make this a suitable model system to investigate the effects of flow on the nonequilibrium phase diagram. Transient rheological experiments are used to determine the critical shear rates at which director tumbling, wagging, and flow-aligning occurs. The present model system enables us to study the effect of rod concentration on these transitions. The results are in quantitatively agreement with the Doi-Edwards-Hess model. Moreover, we observe that there is a strong connection between the dynamic transitions and structure formation, which is not incorporated in theory.
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Affiliation(s)
- M Paul Lettinga
- IFF, Institut Weiche Materie, Forschungszentrum Jülich, D-52425 Jülich, Germany
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21
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Kang K, Gapinski J, Lettinga MP, Buitenhuis J, Meier G, Ratajczyk M, Dhont JKG, Patkowski A. Diffusion of spheres in crowded suspensions of rods. J Chem Phys 2005; 122:44905. [PMID: 15740296 DOI: 10.1063/1.1834895] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Translational tracer diffusion of spherical macromolecules in crowded suspensions of rodlike colloids is investigated. Experiments are done using several kinds of spherical tracers in fd-virus suspensions. A wide range of size ratios L/2a of the length L of the rods and the diameter 2a of the tracer sphere is covered by combining several experimental methods: fluorescence correlation spectroscopy for small tracer spheres, dynamic light scattering for intermediate sized spheres, and video microscopy for large spheres. Fluorescence correlation spectroscopy is shown to measure long-time diffusion only for relatively small tracer spheres. Scaling of diffusion coefficients with a/xi, predicted for static networks, is not found for our dynamical network of rods (with xi the mesh size of the network). Self-diffusion of tracer spheres in the dynamical network of freely suspended rods is thus fundamentally different as compared to cross-linked networks. A theory is developed for the rod-concentration dependence of the translational diffusion coefficient at low rod concentrations for freely suspended rods. The proposed theory is based on a variational solution of the appropriate Smoluchowski equation without hydrodynamic interactions. The theory can, in principle, be further developed to describe diffusion through dynamical networks at higher rod concentrations with the inclusion of hydrodynamic interactions. Quantitative agreement with the experiments is found for large tracer spheres, and qualitative agreement for smaller spheres. This is probably due to the increasing importance of hydrodynamic interactions as compared to direct interactions as the size of the tracer sphere decreases.
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Affiliation(s)
- Kyongok Kang
- Forschungszentrum Jülich, Institute für Festkörper Forschung (IFF), Weiche Materie, D-52425 Jülich, Germany
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22
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Addas KM, Schmidt CF, Tang JX. Microrheology of solutions of semiflexible biopolymer filaments using laser tweezers interferometry. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2004; 70:021503. [PMID: 15447492 DOI: 10.1103/physreve.70.021503] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2004] [Indexed: 05/24/2023]
Abstract
Semiflexible polymers are of great biological importance in determining the mechanical properties of cells. Techniques collectively known as microrheology have recently been developed to measure the viscoelastic properties of solutions of submicroliter volumes. We employ one such technique, which uses a focused laser beam to trap a micron-sized silica bead and interferometric photodiode detection to measure passively the position fluctuations of the trapped bead with nanometer resolution and high bandwidth. The frequency-dependent complex shear modulus G*(f) can be extracted from the position fluctuations via the fluctuation-dissipation theorem and the generalized Stokes-Einstein relation. Using particle tracking microrheology, we report measurements of shear moduli of solutions of fd viruses, which are filamentous, semiflexible, and monodisperse bacteriophages, each 0.9 microm long, 7 nm in diameter, and having a persistence length of 2.2 microm. Recent theoretical treatments of semiflexible polymer dynamics provide quantitative predictions of the rheological properties of such a model system. The fd samples measured span the dilute, semidilute, and concentrated regimes. In the dilute regime G*(f) is dominated by (rigid rod) rotational relaxation, whereas the high-frequency regime reflects single-semiflexible filament dynamics consistent with the theoretical prediction. Due to the short length of fd viruses used in this study, the intermediate regime does not exhibit a well-developed plateau. A dynamic scaling analysis gives rise to a concentration scaling of c(1.36) (r=0.99) in the transition regime and a frequency scaling of f(0.63) (r=0.98) at high frequencies.
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Affiliation(s)
- Karim M Addas
- Department of Physics, Indiana University, 727 East Third Street, Bloomington, Indiana 47405, USA
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24
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Abstract
This review summarizes and assesses recent theoretical and experimental advances, with special emphasis on the effective interaction between charge-stabilized colloids, in the bulk or in confined geometries, and on the ambiguities of defining an effective charge of the colloidal particles. Some consideration is given to the often neglected discrete solvent effects.
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Affiliation(s)
- J P Hansen
- Department of Chemistry, Cambridge University, Cambridge CB2 1EW, United Kingdom.
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25
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Russo PS, Baylis M, Bu Z, Stryjewski W, Doucet G, Temyanko E, Tipton D. Self-diffusion of a semiflexible polymer measured across the lyotropic liquid-crystalline-phase boundary. J Chem Phys 1999. [DOI: 10.1063/1.479435] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Wierenga AM, Philipse AP. Low-shear viscosity of isotropic dispersions of (Brownian) rods and fibres; A review of theory and experiments. Colloids Surf A Physicochem Eng Asp 1998. [DOI: 10.1016/s0927-7757(97)00262-8] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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