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Zhou X, Zhao K. Effect of grafting density on conformation of poly(acrylic acid) in solution by dielectric spectroscopy. SOFT MATTER 2018; 14:7190-7203. [PMID: 30123904 DOI: 10.1039/c8sm00551f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The effect of grafting density of poly(ethylene oxide) and dodecyl groups on the conformation of poly(acrylic acid) in solution was clarified by dielectric relaxation spectroscopy over a frequency range from 40 Hz to 110 MHz. Two distinct dielectric relaxations were found after the elimination of electrode polarization, and valuable information about the conformations and interfacial electrokinetic properties of molecules was obtained by analyzing the dielectric spectra based on a refined double-layer polarization model. The critical aggregation concentration was determined by the concentration dependency of dielectric parameters. The results based on zeta potential suggested that the ionization performance and behavior of counterion condensation were strongly influenced by the grafting density of poly(ethylene oxide) and dodecyl groups. The concentration dependency of correlation length, ratio of zeta potential, ratio of linear density of counterions, and the Debye length showed that the chain length and degree of intermolecular aggregation were also strongly influenced by the grafting density. We revealed the role of grafting density with respect to electrostatic interaction in determining the chain conformation of polyelectrolytes in solution.
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Affiliation(s)
- Xinlu Zhou
- College of Chemistry, Beijing Normal University, Beijing 100875, China.
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2
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Zhou X, Zhao K. Chain conformation of poly(acrylic acid)-graft-poly(ethylene oxide)-graft-dodecyl in solution: an anomalous counter-ions condensation. SOFT MATTER 2018; 14:1130-1141. [PMID: 29345709 DOI: 10.1039/c7sm01931a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A dielectric spectroscopy study on a polyelectrolyte in aqueous solutions, which contains hydrophobic groups in part of the side chains poly(acrylic acid)-graft-poly(ethylene oxide)-graft-dodecyl (PAA-g-PEO-g-dodecyl) is reported. A refined double layer polarization model was proposed to analyze the double dielectric relaxations in the dielectric spectra. Various electrical and structural parameters of the copolymers were obtained. Besides the crossover concentration, another turning point around 4 mg mL-1 was identified through the analysis of all the dielectrical parameters including dielectric increment, relaxation time and correlation length. According to the scaling relationship between the correlation length and concentration, a necklace-like structure was predicted. In addition, 4 mg mL-1 was proven to be the transition point between string-controlling with bead-controlling structure of the chains. In addition, the fraction of effective charges on the chains was illustrated by Ito's counter-ions fluctuation theory, as well as its linear dependence relationship with the zeta potential. Meanwhile, the counter-ions condensation behavior was consistent with the avalanche-like trend, which was predicted by theory for a hydrophobic polyelectrolyte with a necklace conformation. The results demonstrated that the electrostatic interactions were the main driving force of the necklace-like structure with pendant globules when the string-controlling structure was below 4 mg mL-1. While hydrophobic interactions are the main driving force of the structure of bead-controlling above 4 mg mL-1.
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Affiliation(s)
- Xinlu Zhou
- College of Chemistry, Beijing Normal University, Beijing 100875, China.
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3
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Salt-induced reentrant stability of polyion-decorated particles with tunable surface charge density. Colloids Surf B Biointerfaces 2016; 137:109-20. [DOI: 10.1016/j.colsurfb.2015.06.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 06/03/2015] [Accepted: 06/04/2015] [Indexed: 01/17/2023]
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Knöös P, Svensson AV, Ulvenlund S, Wahlgren M. Release of a Poorly Soluble Drug from Hydrophobically Modified Poly (Acrylic Acid) in Simulated Intestinal Fluids. PLoS One 2015; 10:e0140709. [PMID: 26473964 PMCID: PMC4608824 DOI: 10.1371/journal.pone.0140709] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 09/28/2015] [Indexed: 12/02/2022] Open
Abstract
A large part of new pharmaceutical substances are characterized by a poor solubility and high hydrophobicity, which might lead to a difference in drug adsorption between fasted and fed patients. We have previously evaluated the release of hydrophobic drugs from tablets based on Pemulen TR2 and showed that the release can be manipulated by adding surfactants. Here we further evaluate the possibility to use Pemulen TR2 in controlled release tablet formulations containing a poorly soluble substance, griseofulvin. The release is evaluated in simulated intestinal media that model the fasted state (FaSSIF medium) or fed state (FeSSIF). The rheology of polymer gels is studied in separate experiments, in order to gain more information on possible interactions. The release of griseofulvin in tablets without surfactant varied greatly and the slowest release were observed in FeSSIF. Addition of SDS to the tablets eliminated the differences and all tablets showed a slow linear release, which is of obvious relevance for robust drug delivery. Comparing the data from the release studies and the rheology experiment showed that the effects on the release from the different media could to a large extent be rationalised as a consequence of the interactions between the polymer and the surfactants in the media. The study shows that Pemulen TR2 is a candidate for controlled release formulations in which addition of surfactant provides a way to eliminate food effects on the release profile. However, the formulation used needs to be designed to give a faster release rate than the tablets currently investigated.
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Affiliation(s)
- Patrik Knöös
- Department of Chemistry, Division of Physical Chemistry, Lund University, Lund, Sweden
| | | | | | - Marie Wahlgren
- Department of food technology engineering and nutrition, Lund University, Lund, Sweden
- * E-mail:
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Knöös P, Schulz C, Piculell L, Ludwig R, Gorton L, Wahlgren M. Quantifying the release of lactose from polymer matrix tablets with an amperometric biosensor utilizing cellobiose dehydrogenase. Int J Pharm 2014; 468:121-32. [PMID: 24726632 DOI: 10.1016/j.ijpharm.2014.03.060] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 03/28/2014] [Accepted: 03/30/2014] [Indexed: 10/25/2022]
Abstract
The release of lactose (hydrophilic) from polymer tablets made with hydrophobically modified poly(acrylic acid) (HMPAA) have been studied and compared to the release of ibuprofen, a hydrophobic active substance. Lactose is one of the most used excipients for tablets, but lactose release has not been widely studied. One reason could be a lack of good analytical tools. A novel biosensor with cellobiose dehydrogenase (CDH) was used to detect the lactose release, which has a polydiallyldimethylammonium chloride (PDADMAC) layer that increases the response. A sample treatment using polyethylenimine (PEI) was developed to eliminate possible denaturants. The developed methodology provided a good approach to detect and quantify the released lactose. The release was studied with or without the presence of a model amphiphilic substance, sodium dodecyl sulphate (SDS), in the release medium. Ibuprofen showed very different release rates in the different media, which was attributed to hydrophobic interactions between the drug, the HMPAA and the SDS in the release medium. The release of hydrophilic lactose, which did not associate to any of the other components, was rapid and showed only minor differences. The new methodology provides a useful tool to further evaluate tablet formulations by a relatively simple set of experiments.
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Affiliation(s)
- Patrik Knöös
- Division of Physical Chemistry, Lund University, Box 124, Lund SE-22100, Sweden.
| | - Christopher Schulz
- Department of Biochemistry and Structural Biology, Lund University, Box 124, Lund SE-22100, Sweden.
| | - Lennart Piculell
- Division of Physical Chemistry, Lund University, Box 124, Lund SE-22100, Sweden
| | - Roland Ludwig
- Food Biotechnology Laboratory, Department of Food Sciences and Technology, BOKU University of Natural Resources and Life Sciences, Vienna, Austria
| | - Lo Gorton
- Department of Biochemistry and Structural Biology, Lund University, Box 124, Lund SE-22100, Sweden
| | - Marie Wahlgren
- Division of Food Technology, Lund University, Box 124, Lund SE-22100, Sweden.
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Li J, Zhao K. Effect of Side-Chain on Conformation of Poly(acrylic acid) and Its Dielectric Behaviors in Aqueous Solution: Hydrophobic and Hydrogen-Bonding Interactions and Mechanism of Relaxations. J Phys Chem B 2013; 117:11843-52. [DOI: 10.1021/jp404980h] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jingliang Li
- College
of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Kongshuang Zhao
- College
of Chemistry, Beijing Normal University, Beijing 100875, China
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Sulatha MS, Natarajan U. Molecular Dynamics Simulations of PAA–PMA Polyelectrolyte Copolymers in Dilute Aqueous Solution: Chain Conformations and Hydration Properties. Ind Eng Chem Res 2012. [DOI: 10.1021/ie301244n] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Muralidharan S. Sulatha
- Molecular Modeling and Simulation
Lab, Department of Chemical Engineering, Indian Institute of Technology − Madras, Chennai − 600036,
India
| | - Upendra Natarajan
- Molecular Modeling and Simulation
Lab, Department of Chemical Engineering, Indian Institute of Technology − Madras, Chennai − 600036,
India
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Tsortos A, Papadakis G, Gizeli E. The intrinsic viscosity of linear DNA. Biopolymers 2011; 95:824-32. [PMID: 21638275 DOI: 10.1002/bip.21684] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 04/07/2011] [Accepted: 05/20/2011] [Indexed: 11/05/2022]
Abstract
We measured the intrinsic viscosity of very small synthetic DNA molecules, of 20-395 base pairs, and incorporated them in a nearly complete picture for the whole span of molecular weights reported in the literature to date. A major transition is observed at M approximately 2 × 10(6) . It is found that in the range of approximately 7 × 10(3) ≤ M ≤ 2 × 10(6) , the intrinsic viscosity scales as [η] approximately M(1.05) , suggesting that short DNA chains are not as rigid as generally thought. The corresponding scaling for the range of 2 × 10(6) ≤ M ≤ 8 × 10(10) is [η] approximately M(0.69) . A comparison of our results with existing equations, for much narrower data distributions, is made, and the agreement is very satisfactory considering the huge range of data analyzed here. Experimental concerns such as the effect of ionic strength, polydispersity, temperature, and shear rate are discussed in detail. Some issues concerning the Huggins coefficient, polymer chain stiffness, and the relationship between the Mark-Houwink constants K, α are also presented; it is found that log K = 1.156 - 6.19α.
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Affiliation(s)
- Achilleas Tsortos
- Institute of Molecular Biology and Biotechnology, Foundation for Research & Technology - Hellas (FO.R.T.H), Vassilika Vouton, 70013 Heraklion, Greece.
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Zhu X, Choo KH, Park HS. Interactions of nitrates with cationic polyelectrolytes in chelation/ultrafiltration systems for water treatment. J IND ENG CHEM 2009. [DOI: 10.1016/j.jiec.2009.09.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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11
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Dreiss CÃCA. Wormlike micelles: where do we stand? Recent developments, linear rheology and scattering techniques. SOFT MATTER 2007; 3:956-970. [PMID: 32900044 DOI: 10.1039/b705775j] [Citation(s) in RCA: 555] [Impact Index Per Article: 32.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Wormlike micelles are elongated flexible self-assembly structures formed by the aggregation of amphiphiles. Above a threshold concentration, they entangle into a dynamic network, reminiscent of polymer solutions, and display remarkable visco-elastic properties, which have been exploited in numerous industrial and technological fields. Relating the microstructure of these intricate structures with their bulk properties is still an ongoing quest. In this review, we present a classification of wormlike micelles, with a focus on novel systems and applications. We describe the current state of understanding of their linear rheology and give a detailed account of recent progress in small-angle neutron scattering, a particularly powerful technique to elucidate their microstructure on a wide range of length-scales.
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Affiliation(s)
- CÃ Cile A Dreiss
- Pharmaceutical Science Research Division, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, UKSE1 9NH
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de Vasconcelos CL, Pereira MR, Fonseca JLC. Polyelectrolytes in Solution and the Stabilization of Colloids. J DISPER SCI TECHNOL 2005. [DOI: 10.1081/dis-200040170] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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13
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Rushing T, Hester R. Semi-empirical model for polyelectrolyte intrinsic viscosity as a function of solution ionic strength and polymer molecular weight. POLYMER 2004. [DOI: 10.1016/j.polymer.2004.07.029] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Kirwan LJ, Fawell PD, van Bronswijk W. An in situ FTIR-ATR study of polyacrylate adsorbed onto hematite at high pH and high ionic strength. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:4093-100. [PMID: 15969402 DOI: 10.1021/la036248u] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
FTIR-ATR was used to examine in situ the interaction of polyacrylate and hematite at pH 13. Static light scattering and mobility measurements were used to assess solution polyacrylate dimensions and hematite surface charge, respectively. Polyacrylate adsorption occurred only with the addition of electrolyte (e.g., NaCl), and it was found that excess cations, up to approximately 1 M, facilitated adsorption, above which the effect was found to plateau. At pH 13 and at low ionic strength, adsorption of polyacrylate onto hematite is facilitated by cations in solution shielding both the negative acrylate functionality of the polymer and the negative hematite surface. The shielding of the hematite surface continues to increase with increasing salt concentration up to a measured 3 M. Similarly, the shielding of the polymer increased with electrolyte concentration up to approximately 1 M salt, beyond which no further increase in shielding was observed. At this concentration the polymer assumes a finite minimum size in solution that ultimately limits the amount adsorbed. The dimension of the polymer in solution was found to be independent of monovalent cation type. Thus, at high pH and high ionic strength adsorption is determined by the degree of hematite surface charge reduction. The cation-hematite surface interaction was found to be specific, with lithium leading to greater polyacrylate adsorption than sodium, which was followed by cesium. The stronger affinity of lithium for the hematite surface over sodium and cesium is indicative of the inverse lyotropic adsorption series and has been rationalized in the past by the "structure-making-structure-breaking" model. These results provide a useful insight into the likely adsorption mechanism for polyacrylate flocculants at high pH and ionic strength onto residues in the Bayer processing of bauxite.
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Affiliation(s)
- Luke J Kirwan
- A. J. Parker Cooperative Research Centre for Hydrometallurgy, Department of Applied Chemistry, Curtin University of Technology, G.P.O. Box U1987, Perth, WA 6845, Australia
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Taylor TJ, Stivala SS. Small-angle X-ray scattering study of a weak polyelectrolyte in water. ACTA ACUST UNITED AC 2003. [DOI: 10.1002/polb.10460] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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16
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Fernandes ALP, Martins RR, da Trindade Neto CG, Pereira MR, Fonseca JLC. Characterization of polyelectrolyte effect in poly(acrylic acid) solutions. J Appl Polym Sci 2003. [DOI: 10.1002/app.12175] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Bordi F, Colby RH, Cametti C, De Lorenzo L, Gili T. Electrical Conductivity of Polyelectrolyte Solutions in the Semidilute and Concentrated Regime: The Role of Counterion Condensation. J Phys Chem B 2002. [DOI: 10.1021/jp020262i] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- F. Bordi
- Dipartimento di Medicina Interna, Universita' di Roma “Tor Vergata”, Istituto Nazionale per la Fisica della Materia (INFM), Unita' di Roma1, Rome, Italy
| | - R. H. Colby
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - C. Cametti
- Dipartimento di Fisica, Universita' di Roma “La Sapienza”, Piazzale A. Moro 5 and Istituto Nazionale per la Fisica della Materia (INFM), Unita' di Roma1, I-00185 Rome, Italy
| | - L. De Lorenzo
- Dipartimento di Fisica, Universita' di Roma “La Sapienza”, Piazzale A. Moro 5 and Istituto Nazionale per la Fisica della Materia (INFM), Unita' di Roma1, I-00185 Rome, Italy
| | - T. Gili
- Dipartimento di Fisica, Universita' di Roma “La Sapienza”, Piazzale A. Moro 5 and Istituto Nazionale per la Fisica della Materia (INFM), Unita' di Roma1, I-00185 Rome, Italy
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