1
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Control of the aqueous solubility of cellulose by hydroxyl group substitution and its effect on processing. POLYMER 2021. [DOI: 10.1016/j.polymer.2021.123681] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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2
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Krakovský I, Hanyková L, Paladini G, Almásy L. SANS and NMR study on nanostructure of thermoresponsive double network hydrogels. Eur Polym J 2020. [DOI: 10.1016/j.eurpolymj.2020.109929] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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3
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Horkay F, Chremos A, Douglas JF, L Jones R, Lou J, Xia Y. Systematic investigation of synthetic polyelectrolyte bottlebrush solutions by neutron and dynamic light scattering, osmometry, and molecular dynamics simulation. J Chem Phys 2020; 152:194904. [PMID: 33687251 DOI: 10.1063/5.0007271] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
There is a great interest in the synthesis and characterization of polyelectrolytes that mimic naturally occurring bottlebrush polyelectrolytes to capitalize on the unique properties of this class of macromolecules. Charged bottlebrush polymers form the protective mucus layer in the lungs, stomach, and orifices of animals and provide osmotic stabilization and lubrication to joints. In the present work, we systematically investigate bottlebrush poly(sodium acrylates) through a combination of measurements of solution properties (osmometry, small-angle neutron scattering, and dynamic light scattering) and molecular dynamics simulations, where the bottlebrush properties are compared in each case to their linear polymer counterparts. These complementary experimental and computational methods probe vastly different length- and timescales, allowing for a comprehensive characterization of the supermolecular structure and dynamics of synthetic polyelectrolyte bottlebrush molecules in solution.
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Affiliation(s)
- Ferenc Horkay
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Alexandros Chremos
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Jack F Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Ronald L Jones
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Junzhe Lou
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Yan Xia
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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4
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Mussel M, Basser PJ, Horkay F. Effects of mono- and divalent cations on the structure and thermodynamic properties of polyelectrolyte gels. SOFT MATTER 2019; 15:4153-4161. [PMID: 31062008 PMCID: PMC6531340 DOI: 10.1039/c9sm00464e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Measurements are reported on the effect of monovalent and divalent salts on the swelling behavior and supramolecular structure of sodium polyacrylate gels (NaPA) made by osmotic swelling pressure and small angle neutron scattering measurements. The swelling response of the gels in solutions of ten different monovalent salts is found to be practically identical indicating that the principal effect of monovalent ions is screening the electrostatic repulsion among the charged groups on the polyelectrolyte chains; i.e., chemical differences between the monovalent ions do not play a significant role. Introducing Ca2+ ions into the equilibrium NaCl solution results in a sharp volume transition of the gels. The threshold Ca2+ ion concentration at which the transition occurs increases with increasing NaCl concentration in the surrounding bath. It is demonstrated that the swelling behavior of NaPA gels exhibits universal properties in solutions containing both NaCl and CaCl2. Osmotic swelling pressure measurements reveal that both the second and third virial coefficients decrease with increasing CaCl2 concentration until the volume transition is reached. The macroscopic measurements are complemented by small angle neutron scattering that reveals the variation of the thermodynamic length scales as the volume transition is approached. The thermodynamic correlation length L increases with increasing CaCl2 concentration.
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5
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Horkay F, Nishi K, Shibayama M. Decisive test of the ideal behavior of tetra-PEG gels. J Chem Phys 2018; 146:164905. [PMID: 28456212 DOI: 10.1063/1.4982253] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The objective of this work is to investigate the thermodynamic and scattering behavior of tetra-poly(ethylene glycol) (PEG) gels. Complementary measurements, including osmotic swelling pressure, elastic modulus, and small angle neutron scattering (SANS), are reported for a series of tetra-PEG gels made from different molecular weight precursor chains at different concentrations. Analysis of the osmotic swelling pressure vs polymer volume fraction curves makes it possible to separate the elastic and mixing contributions of the network free energy. It is shown that in tetra-PEG gels these free energy components are additive. The elastic term varies with the one-third power of the polymer volume fraction and its numerical value is equal to the shear modulus obtained from independent mechanical measurements. The mixing pressure of the cross-linked polymer is slightly smaller than that of the corresponding solution of the uncross-linked polymer of infinite molecular weight but it exhibits similar dependence on the polymer concentration. The observed deviation between the osmotic mixing pressures of the gel and the solution can be attributed to the presence of small amount of structural inhomogeneities frozen-in by the cross-links. SANS reveals that the scattering response of tetra-PEG gel is mainly governed by the thermodynamic concentration fluctuations of the network, i.e., the contribution from static inhomogeneities to the SANS signal is small.
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Affiliation(s)
- Ferenc Horkay
- Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Kengo Nishi
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Mitsuhiro Shibayama
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
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6
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Supramolecular structure of methyl cellulose and lambda- and kappa-carrageenan in water: SAXS study using the string-of-beads model. Carbohydr Polym 2017; 172:184-196. [PMID: 28606524 DOI: 10.1016/j.carbpol.2017.04.048] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 04/11/2017] [Accepted: 04/18/2017] [Indexed: 12/24/2022]
Abstract
A detailed data analysis utilizing the string-of-beads model was performed on experimental small-angle X-ray scattering (SAXS) curves in a targeted structural study of three, very important, industrial polysaccharides. The results demonstrate the quality of performance for this model on three polymers with quite different thermal structural behavior. Furthermore, they show the advantages of the model used by way of excellent fits in the ranges where the classic approach to the small-angle scattering data interpretation fails and an additional 3D visualization of the model's molecular conformations and anticipated polysaccharide supramolecular structure. The importance of this study is twofold: firstly, the methodology used and, secondly, the structural details of important biopolymers that are widely applicable in practice.
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7
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8
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Benigar E, Zupančič Valant A, Dogsa I, Sretenovic S, Stopar D, Jamnik A, Tomšič M. Structure and Dynamics of a Model Polymer Mixture Mimicking a Levan-Based Bacterial Biofilm of Bacillus subtilis. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:8182-8194. [PMID: 27438223 DOI: 10.1021/acs.langmuir.6b02041] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In this paper, we report on the structure and dynamics of biologically important model polymer mixtures that mimic the extracellular polymeric matrix in native biofilm of Bacillus subtilis. This biofilm is rich in nonionic polysaccharide levan, but also contains other biopolymers such as DNA and proteins in small concentrations. Aiming to identify the contribution of each component to the formation of the biofilm, our investigations encompassed dynamic rheology, small-angle X-ray scattering, dynamic light scattering, microscopy, densitometry, and sound velocity measurements. As it turned out, this very powerful combination of techniques is able to provide solid results on the dynamical and structural aspects of the microbiologically and chemically complex biofilm formations. Macroscopic rheological measurements revealed that the addition of DNA to levan solution increased the viscosity, pseudoplasticity, and elasticity of the system. The addition of protein contributed similarly, but also increased the rigidity of the system. This confirms that the presence of minor biofilm components is essential for biofilm formation. DNA and proteins appear to confine levan molecules within their supramolecular structure and, in this way, restrict the role of levan to merely a filling agent. These findings were complemented by small-angle X-ray scattering data, which provided insight into the structure on a molecular scale. One of the essential goals of this work was to compare the structural properties of the native biofilm and synthetic biofilm mixture.
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Affiliation(s)
- Elizabeta Benigar
- Faculty of Chemistry and Chemical Technology and Biotechnical Faculty, University of Ljubljana , Večna pot 113, SI-1000 Ljubljana, Slovenia
| | - Andreja Zupančič Valant
- Faculty of Chemistry and Chemical Technology and Biotechnical Faculty, University of Ljubljana , Večna pot 113, SI-1000 Ljubljana, Slovenia
| | - Iztok Dogsa
- Biotechnical Faculty, University of Ljubljana , Večna pot 111, SI-1000, Ljubljana, Slovenia
| | - Simon Sretenovic
- Biotechnical Faculty, University of Ljubljana , Večna pot 111, SI-1000, Ljubljana, Slovenia
| | - David Stopar
- Biotechnical Faculty, University of Ljubljana , Večna pot 111, SI-1000, Ljubljana, Slovenia
| | - Andrej Jamnik
- Faculty of Chemistry and Chemical Technology and Biotechnical Faculty, University of Ljubljana , Večna pot 113, SI-1000 Ljubljana, Slovenia
| | - Matija Tomšič
- Faculty of Chemistry and Chemical Technology and Biotechnical Faculty, University of Ljubljana , Večna pot 113, SI-1000 Ljubljana, Slovenia
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9
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Ducrot E, Montes H, Creton C. Structure of Tough Multiple Network Elastomers by Small Angle Neutron Scattering. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b01979] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Etienne Ducrot
- Sciences
et Ingénierie de la Matière Molle, CNRS UMR 7615, École
Supérieure de Physique et de Chimie Industrielles de la Ville
de Paris (ESPCI), ParisTech, PSL Research University, 10 rue Vauquelin, F-75231 Paris cedex 05, France
- SIMM,
UPMC Univ Paris 06, Sorbonne-Universités, 10 rue Vauquelin, F-75231 Paris cedex 05, France
| | - Helene Montes
- Sciences
et Ingénierie de la Matière Molle, CNRS UMR 7615, École
Supérieure de Physique et de Chimie Industrielles de la Ville
de Paris (ESPCI), ParisTech, PSL Research University, 10 rue Vauquelin, F-75231 Paris cedex 05, France
- SIMM,
UPMC Univ Paris 06, Sorbonne-Universités, 10 rue Vauquelin, F-75231 Paris cedex 05, France
| | - Costantino Creton
- Sciences
et Ingénierie de la Matière Molle, CNRS UMR 7615, École
Supérieure de Physique et de Chimie Industrielles de la Ville
de Paris (ESPCI), ParisTech, PSL Research University, 10 rue Vauquelin, F-75231 Paris cedex 05, France
- SIMM,
UPMC Univ Paris 06, Sorbonne-Universités, 10 rue Vauquelin, F-75231 Paris cedex 05, France
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10
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Benigar E, Dogsa I, Stopar D, Jamnik A, Kralj Cigić I, Tomšič M. Structure and dynamics of a polysaccharide matrix: aqueous solutions of bacterial levan. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:4172-4182. [PMID: 24654746 DOI: 10.1021/la500830j] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The polysaccharide levan is a homopolymer of fructose and appears in nature as an important structural component of some bacterial biofilms. This paper reports the structural and dynamic properties of aqueous solutions of levan of various origin obtained from dynamic rheological, small-angle X-ray scattering, static and dynamic light scattering, as well as density and sound velocity measurements, determination of polymer branching after per-O-methylation, and microscopy. Besides samples of commercially available levan from Zymomonas mobilis and Erwinia herbicola, we also isolated, purified, and studied a levan sample from the biofilm of Bacillus subtilis. The results of dynamic rheological and light scattering measurements revealed very interesting viscoelastic properties of levan solutions even at very low polymer concentrations. The findings were complemented by small-angle X-ray scattering data that revealed some important differences in the structure of the aqueous levan solutions at the molecular level. Besides presenting detailed dynamic and structural results on the polysaccharide systems of various levans, one of the essential goals of this work was to point out the level of structural information that may be obtained for such polymer systems by combining basic physicochemical, rheological, and various light scattering techniques.
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Affiliation(s)
- Elizabeta Benigar
- Faculty of Chemistry and Chemical Technology, University of Ljubljana , Aškerčeva 5, SI-1000 Ljubljana, Slovenia
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11
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Affiliation(s)
- Ferenc Horkay
- Section on Tissue Biophysics and Biomimetics; NICHD, National Institutes of Health; 13 South Drive; Bethesda; MD; 20892; USA
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12
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Hyaluronic acid methacrylate derivatives and calcium alginate interpenetrated hydrogel networks for biomedical applications: physico-chemical characterization and protein release. Colloid Polym Sci 2012. [DOI: 10.1007/s00396-012-2735-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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13
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Medina-Gonzalez Y, Lasseuguette E, Rouch JC, Remigy JC. Improving PVDF Hollow Fiber Membranes for CO2Gas Capture. SEP SCI TECHNOL 2012. [DOI: 10.1080/01496395.2012.658942] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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14
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Horkay F, Basser PJ, Hecht AM, Geissler E. Chondroitin Sulfate in Solution: Effects of Mono- and Divalent Salts. Macromolecules 2012; 45:2882-2890. [PMID: 23814316 PMCID: PMC3694629 DOI: 10.1021/ma202693s] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Chondroitin sulphate (CS) is a linear sulfated polysaccharide found in cartilage and other tissues in the body. Small angle neutron scattering (SANS) and dynamic light scattering (DLS) measurements are made on semi-dilute CS solutions to determine ion induced changes in the local order of the CS chains and in their dynamic properties. In salt-free CS solutions SANS detects the correlation peak due to local ordering between adjacent chains in which the characteristic interchain distance is d ≈ 57 Å. In both monovalent and divalent salts (NaCl and CaCl2) aligned linear regions are distinguishable corresponding to distance scales ranging from the length of the monomer unit (8 Å) to about 1000 Å. With increasing calcium ion concentration, the scattering intensity increases. Even in the presence of 200 mM CaCl2, however, neither phase separation nor cross-linking occurs. DLS in the CS solutions reveals two characteristic relaxation modes, the fast mode corresponding to the thermal concentration fluctuations. The collective diffusion coefficient D decreases with increasing calcium ion concentration and exhibits a power law function of the single variable c/J, where c is the CS concentration and J is the ionic strength of the salt in the solution. This result implies that the effect of the sodium and calcium ions on the dynamic properties of CS solutions is fully accounted for by the ionic strength.
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Affiliation(s)
- Ferenc Horkay
- Section on Tissue Biophysics and Biomimetics, Program in Pediatric Imaging and Tissue Science, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 13 South Drive, Bethesda, MD 20892, USA
| | - Peter J. Basser
- Section on Tissue Biophysics and Biomimetics, Program in Pediatric Imaging and Tissue Science, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 13 South Drive, Bethesda, MD 20892, USA
| | - Anne-Marie Hecht
- Laboratoire Interdisciplinaire de Physique CNRS UMR 5588, Université J. Fourier de Grenoble, B.P.87, 38402 St Martin d'Hères cedex, France
| | - Erik Geissler
- Laboratoire Interdisciplinaire de Physique CNRS UMR 5588, Université J. Fourier de Grenoble, B.P.87, 38402 St Martin d'Hères cedex, France
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15
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Horkay F, Cho SH, Tathireddy P, Rieth L, Solzbacher F, Magda J. Thermodynamic Analysis of the Selectivity Enhancement Obtained by Using Smart Hydrogels That Are Zwitterionic When Detecting Glucose With Boronic Acid Moieties. SENSORS AND ACTUATORS. B, CHEMICAL 2011; 160:1363-1371. [PMID: 22190765 PMCID: PMC3242003 DOI: 10.1016/j.snb.2011.09.079] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Because the boronic acid moiety reversibly binds to sugar molecules and has low cytotoxicity, boronic acid-containing hydrogels are being used in a variety of implantable glucose sensors under development, including sensors based on optical, fluorescence, and swelling pressure measurements. However, some method of glucose selectivity enhancement is often necessary, because isolated boronic acid molecules have a binding constant with glucose that is some forty times smaller than their binding constant with fructose, the second most abundant sugar in the human body. In many cases, glucose selectivity enhancement is obtained by incorporating pendant tertiary amines into the hydrogel network, thereby giving rise to a hydrogel that is zwitterionic at physiological pH. However, the mechanism by which incorporation of tertiary amines confers selectivity enhancement is poorly understood. In order to clarify this mechanism, we use the osmotic deswelling technique to compare the thermodynamic interactions of glucose and fructose with a zwitterionic smart hydrogel containing boronic acid moieties. We also investigate the change in the structure of the hydrogel that occurs when it binds to glucose or to fructose using the technique of small angle neutron scattering.
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Affiliation(s)
- F. Horkay
- Section on Tissue Biophysics and Biomimetics, Program on Pediatric Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-5772 USA
| | - S. H. Cho
- Department of Chemical Engineering, University of Utah, Salt Lake City, Utah 84112 USA
| | - P. Tathireddy
- Department of Electrical & Computer Engineering, University of Utah, Salt Lake City, Utah 84112 USA
| | - L. Rieth
- Department of Electrical & Computer Engineering, University of Utah, Salt Lake City, Utah 84112 USA
| | - F. Solzbacher
- Department of Electrical & Computer Engineering, University of Utah, Salt Lake City, Utah 84112 USA
- Department of Materials Science & Engineering, University of Utah, Salt Lake City, Utah 84112 USA
- Department of Bioengineering, University of Utah, Salt Lake City, Utah 84112 USA
| | - J. Magda
- Department of Chemical Engineering, University of Utah, Salt Lake City, Utah 84112 USA
- Department of Materials Science & Engineering, University of Utah, Salt Lake City, Utah 84112 USA
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16
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Horkay F, Magda J, Alcoutlabi M, Atzet S, Zarembinski T. Structural, mechanical and osmotic properties of injectable hyaluronan-based composite hydrogels. POLYMER 2010; 51:4424-4430. [PMID: 20824199 DOI: 10.1016/j.polymer.2010.06.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The osmotic and scattering properties of hyaluronan-based composite hydrogels composed of stiff biopolymer chains (carboxymethylated thiolated hyaluronan (CMHA-S)) crosslinked by a flexible polymer (polyethylene glycol diacrylate (PEGDA)) are investigated and analyzed in terms of the scaling theory. The total pre-gel polymer weight concentration is varied between 0.5 wt.% and 3.2 wt.%, while the mole ratio between the reactive PEG chain ends and the thiolated HA moieties is changed between 0.15 and 1.0. The shear modulus G of the fully swollen gels exhibits a stronger dependence on pre-gel concentration than on the crosslink density. Osmotic deswelling measurements reveal that the osmotic mixing pressure depends on the weight ratio CMHA-S/PEGDA, and is practically unaffected by the pre-gel concentration. Small-angle neutron scattering observations indicate that the thermodynamic properties of these composite gels are governed by total polymer concentration, i.e., specific interactions between the two polymeric components do not play a significant role.
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Affiliation(s)
- Ferenc Horkay
- Section on Tissue Biophysics and Biomimetics, Program on Pediatric Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 13 South Drive, Bethesda, MD 20892-5772
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17
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Mang JT, Hjelm RP, Orler EB, Wrobleski DA. Small-Angle Neutron Scattering of a Solvent-Swollen Segmented Polyurethane as a Probe of Solvent Distribution and Polymer Domain Composition. Macromolecules 2008. [DOI: 10.1021/ma800015g] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Joseph T. Mang
- Dynamic Experimentation Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545; Manuel Lujan, Jr. Neutron Scattering Center, Los Alamos National Laboratory, Los Alamos, New Mexico 87545; and Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
| | - Rex P. Hjelm
- Dynamic Experimentation Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545; Manuel Lujan, Jr. Neutron Scattering Center, Los Alamos National Laboratory, Los Alamos, New Mexico 87545; and Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
| | - E. Bruce Orler
- Dynamic Experimentation Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545; Manuel Lujan, Jr. Neutron Scattering Center, Los Alamos National Laboratory, Los Alamos, New Mexico 87545; and Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
| | - Debra A. Wrobleski
- Dynamic Experimentation Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545; Manuel Lujan, Jr. Neutron Scattering Center, Los Alamos National Laboratory, Los Alamos, New Mexico 87545; and Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
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18
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Lin WC, Shull KR, Hui CY, Lin YY. Contact measurement of internal fluid flow within poly(n-isopropylacrylamide) gels. J Chem Phys 2007; 127:094906. [PMID: 17824764 DOI: 10.1063/1.2771167] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A technique is presented that is ideally suited for characterizing the mechanical and transport properties of polymer gels at small strains. A flat, circular punch and a flat, rectangular punch are used to probe the response of gels under oscillatory loading conditions. Solvent transport within the gel is driven by gradients in hydrostatic pressure, giving rise to a dissipative response quantified by the phase lag between the punch displacement and the resulting load. By comparing results for different punch sizes, it is possible to differentiate between dissipation resulting from internal solvent flow and dissipation due to the viscoelastic character of the polymer network itself. Use of the technique is illustrated with poly(n-isopropylacrylamide) gels, which undergo a reversible structural transition just above room temperature. We show that heterogeneous structure formed above the transition temperature is not conducive to internal solvent flow within these gels.
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Affiliation(s)
- Wei-Chun Lin
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.
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19
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Affiliation(s)
- B. Hammouda
- Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Stop 8562, Building 235, E151, Gaithersburg, Maryland 20899-8562
| | - D. Ho
- Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Stop 8562, Building 235, E151, Gaithersburg, Maryland 20899-8562
| | - S. Kline
- Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Stop 8562, Building 235, E151, Gaithersburg, Maryland 20899-8562
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20
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Gilra N, Cohen C, Briber RM, Bauer BJ, Hedden RC, Panagiotopoulos AZ. A SANS Study of the Conformational Behavior of Linear Chains in Compressed and Uncompressed End-Linked Elastomers. Macromolecules 2001. [DOI: 10.1021/ma010018+] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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21
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22
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Yim H, Kent M, McNamara WF, Ivkov R, Satija S, Majewski J. Structure within Thin Epoxy Films Revealed by Solvent Swelling: A Neutron Reflectivity Study. Macromolecules 1999. [DOI: 10.1021/ma990990c] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | | | | | | | - J. Majewski
- LANCSE, Los Alamos National Laboratories, Los Alamos, New Mexico
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