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Allegri G, Huskens J, Martinho RP, Lindhoud S. Distribution of polyelectrolytes and counterions upon polyelectrolyte complexation. J Colloid Interface Sci 2024; 672:654-663. [PMID: 38865879 DOI: 10.1016/j.jcis.2024.06.062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Revised: 06/06/2024] [Accepted: 06/06/2024] [Indexed: 06/14/2024]
Abstract
HYPOTHESIS Understanding polyelectrolyte complexation remains limited due to the absence of a systematic methodology for analyzing the distribution of components between the polyelectrolyte complex (PEC) and the dilute phases. EXPERIMENTS We developed a methodology based on NMR to quantify all components of solid-like PECs and their supernatant phases formed by mixing different ratios of poly(allylamine hydrochloride) (PAH) and poly(acrylic acid)-sodium salt (PAA). This approach allowed for determining relative and absolute concentrations of polyelectrolytes in both phases by 1H NMR studies. Using 23Na and 35Cl NMR spectroscopy we measured the concentration of counterions in both phases. FINDINGS Regardless of the mixing ratio of the polyelectrolytes the PEC is charge-stoichiometric, and any excess polyelectrolytes to achieve charge stoichiometry remains in the supernatant phase. The majority of counterions were found in the supernatant phase, confirming counterion release being a major thermodynamic driving force for PEC formation. The counterion concentrations in the PEC phase were approximately twice as high as in the supernatant phase. The complete mass balance of PEC formation could be determined and translated into a molecular picture. It appears that PAH is fully charged, while PAA is more protonated, so less charged, and some 10% extrinsic PAH-Cl- pairs are present in the complex.
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Affiliation(s)
- Giulia Allegri
- Molecular Nanofabrication Group, Department for Molecules & Materials, MESA+ Institute & Faculty of Science Technology, University of Twente, 7500 AE Enschede, the Netherlands.
| | - Jurriaan Huskens
- Molecular Nanofabrication Group, Department for Molecules & Materials, MESA+ Institute & Faculty of Science Technology, University of Twente, 7500 AE Enschede, the Netherlands.
| | - Ricardo P Martinho
- Biomolecular Nanotechnology Group, Department for Molecules & Materials, MESA+ Institute & Faculty of Science Technology, University of Twente, 7500 AE Enschede, the Netherlands.
| | - Saskia Lindhoud
- Molecular Nanofabrication Group, Department for Molecules & Materials, MESA+ Institute & Faculty of Science Technology, University of Twente, 7500 AE Enschede, the Netherlands.
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G Lopez C, Matsumoto A, Shen AQ. Dilute polyelectrolyte solutions: recent progress and open questions. SOFT MATTER 2024; 20:2635-2687. [PMID: 38427030 DOI: 10.1039/d3sm00468f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
Polyelectrolytes are a class of polymers possessing ionic groups on their repeating units. Since counterions can dissociate from the polymer backbone, polyelectrolyte chains are strongly influenced by electrostatic interactions. As a result, the physical properties of polyelectrolyte solutions are significantly different from those of electrically neutral polymers. The aim of this article is to highlight key results and some outstanding questions in the polyelectrolyte research from recent literature. We focus on the influence of electrostatics on conformational and hydrodynamic properties of polyelectrolyte chains. A compilation of experimental results from the literature reveals significant disparities with theoretical predictions. We also discuss a new class of polyelectrolytes called poly(ionic liquid)s that exhibit unique physical properties in comparison to ordinary polyelectrolytes. We conclude this review by listing some key research challenges in order to fully understand the conformation and dynamics of polyelectrolytes in solutions.
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Affiliation(s)
- Carlos G Lopez
- Institute of Physical Chemistry, RWTH Aachen University, Aachen, 52056, Germany
| | - Atsushi Matsumoto
- Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui City, Fukui 910-8507, Japan.
| | - Amy Q Shen
- Micro/Bio/Nanofluidics Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan.
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Bujok S, Konefał R, Nevoralová M, Bednarz S, Mielczarek K, Beneš H. Cation identity in clay-polyelectrolyte self-assembled hydrogels: Rheological and NMR study of the polyitaconate-counterion interactions. Colloids Surf A Physicochem Eng Asp 2023. [DOI: 10.1016/j.colsurfa.2022.130346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Lopez CG, Linders J, Mayer C, Richtering W. Diffusion and Viscosity of Unentangled Polyelectrolytes. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c01169] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Carlos G. Lopez
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany
| | - Jürgen Linders
- Physical Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, 45117 Essen, Germany
| | - Christian Mayer
- Physical Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, 45117 Essen, Germany
| | - Walter Richtering
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany
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Liang J, Xiao X, Chou TM, Libera M. Analytical Cryo-Scanning Electron Microscopy of Hydrated Polymers and Microgels. Acc Chem Res 2021; 54:2386-2396. [PMID: 33944550 DOI: 10.1021/acs.accounts.1c00109] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Despite the fact that scanning electron microscopes (SEM) coupled with energy-dispersive X-ray microanalysis (EDS) has been commercially available for more than a half-century, SEM/EDS continues to develop and open new opportunities to study the morphology of advanced materials. This is particularly true in applications to hydrated soft matter. Developments in field-emission electron sources that enable low-voltage imaging of uncoated polymers, silicon-drift detectors that enable high-efficiency collection of X-rays characteristic of light elements, and cryogenic methods to effectively cryo-fix hydrated samples have opened new opportunities to apply techniques relatively well established in hard-materials applications to challenging new problems involving synthetic polymers. We have applied cryo-SEM imaging and spatially resolved EDS to collect new information characterizing polyelectrolyte microgels. These are charged gel particles with dimensions in the range of 0.1-100 μm. Perhaps most notable is the fact that the high hydration levels-the samples are mostly water-allow robust calibration curves to be generated using frozen-hydrated buffers with known salt and/or hydrocarbon compositions. Such calibration curves enable quantitative composition measurements in the low-concentration extremes associated with high-swelling hydrogels. We use an experimentally derived carbon calibration curve to determine the microgel swell ratio, Q. The swell ratio, arguably, is the single most important gel characteristic because it is directly related to the mesh size of the networked polymer, which in turn determines many of the gel's mechanical and transport properties. While Q can be experimentally measured in macroscopic gels based on weight measurements in the dry and hydrated states, it is very difficult to measure in a microgel, and the fact that EDS in a cryo-SEM can determine Q from a single X-ray spectrum is significant. Furthermore, because of the electrostatic charge distributed along the polymer chains, the presence and concentration of counter-ions play a critical role in polyelectrolyte systems. While conceptually understood for decades, experimental measurements of counter-ion concentrations have been largely limited to a relatively small set of materials that involve macroscopic samples. By developing calibration curves from frozen-hydrated buffer of known ionic strength, we measure the concentration of Na counter-ions in microgels of poly(acrylic acid) (PAA) with a limit of detection of ∼0.014 M. Such measurements may help resolve some long-standing questions in polyelectrolyte science concerning counter-ion condensation. Even in the absence of a calibration curve, we show that spatially resolved X-ray spectroscopy can map the spatial distribution of a cationic oligopeptide complexed within a hydrated PAA microgel because of the nitrogen fingerprint that, albeit at very low concentration, is unique to the peptide. We look specifically at the case of a microgel with a so-called core-shell structure, where, again, the underlying polyelectrolyte science responsible for core-shell formation remains incompletely understood. These examples highlight how a modern cryo-SEM can be exploited to quantitatively characterize hydrated soft matter. The approach is almost certain to continue its development and impact as the base of experienced practitioners, the accessibility to well-configured microscopes, and the abundance of challenging problems involving hydrated soft matter all continue to grow.
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Affiliation(s)
- Jing Liang
- Stevens Institute of Technology Hoboken, New Jersey 07030, United States
| | - Xixi Xiao
- Stevens Institute of Technology Hoboken, New Jersey 07030, United States
| | - Tseng-Ming Chou
- Stevens Institute of Technology Hoboken, New Jersey 07030, United States
| | - Matthew Libera
- Stevens Institute of Technology Hoboken, New Jersey 07030, United States
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Schulze-Zachau F, Bachmann S, Braunschweig B. Effects of Ca 2+ Ion Condensation on the Molecular Structure of Polystyrene Sulfonate at Air-Water Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:11714-11722. [PMID: 30188134 PMCID: PMC6170951 DOI: 10.1021/acs.langmuir.8b02631] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 09/05/2018] [Indexed: 06/02/2023]
Abstract
The structure of poly(sodium 4-styrenesulfonate) (NaPSS) polyelectrolytes at air-water interfaces was investigated with tensiometry, ellipsometry, and vibrational sum-frequency generation (SFG) in the presence of low and high CaCl2 concentrations. In addition, we have studied the foaming behavior of 20 mM NaPSS solutions to relate the PSS molecular structure at air-water interfaces to foam properties. PSS polyelectrolytes without additional salt exhibited significant surface activity, which can be tuned further by additions of CaCl2. The hydrophobicity of the backbone due to incomplete sulfonation during synthesis is one origin, whereas the effective charge of the polyelectrolyte chain is shown to play another major role. At low salt concentrations, we propose that the polyelectrolyte is forming a layered structure. The hydrophobic parts are likely to be located directly at the interface in loops, whereas the hydrophilic parts are at low concentrations stretched out into near-interface regions in tails. Increasing the Ca2+ concentration leads to ion condensation, a collapse of the tails, and likely to Ca2+ intra- and intermolecular bridges between polyelectrolytes at the interface. The increase in both surface excess and foam stability originates from changes in the polyelectrolyte's hydrophobicity due to Ca2+ condensation onto the PSS polyanions. Consequently, charge screening at the interface is enhanced and repulsive electrostatic interactions are reduced. Furthermore, SFG spectra of O-H stretching bands reveal a decrease in intensity of the low-frequency branch when c(Ca2+) is increased whereas the high-frequency branch of O-H stretching modes persists even for 1 M CaCl2. This originates from the remaining net charge of the PSS polyanions at the air-water interface that is not fully compensated by condensation of Ca2+ ions and leads to electric-field-induced contributions to the SFG spectra of interfacial H2O. A charge reversal of the PSS net charge at the air-water interface is not observed and is consistent with bulk electrophoretic mobility measurements.
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Affiliation(s)
- Felix Schulze-Zachau
- Institute
of Physical Chemistry and Center for Soft Nanoscience, Westfälische Wilhelms-Universität Münster, Corrensstraße 28/30, 48149 Münster, Germany
| | - Silvia Bachmann
- Institute
of Particle Technology (LFG), Friedrich-Alexander-Universität
Erlangen-Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany
| | - Björn Braunschweig
- Institute
of Physical Chemistry and Center for Soft Nanoscience, Westfälische Wilhelms-Universität Münster, Corrensstraße 28/30, 48149 Münster, Germany
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Zhou X, Zhao K. How side chains affect conformation and electrical properties of poly(acrylic acid) in solution? Phys Chem Chem Phys 2017; 19:20559-20572. [PMID: 28730200 DOI: 10.1039/c7cp02460f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
To better understand the effect of side chains on the chain conformation and electrical properties of polyelectrolytes, dielectric measurements were carried out on solutions of poly(acrylic acid) (PAA), poly(acrylic acid)-graft-dodecyl (PAA-g-dodecyl), and poly(acrylic acid)-graft-poly(ethylene oxide) (PAA-g-PEO) over a wide concentration range. Double dielectric relaxations with counterion distribution were observed for these polymers and a refined double-layer polarization model was proposed to analyze these, by which valuable information about conformations and interfacial electrokinetic properties was obtained. The transitional concentrations for the overlapping and entanglement of chains were identified from results for the dielectric increment and relaxation time. The concentration dependences of the ratio of effective charges were estimated from conductivity data. It was shown that effective charges on PAA were greatly influenced by PEO or dodecyl side chains, which caused steric hindrance of counterion binding and further dissociation of carboxylic groups or bound counterions. Moreover, a mutual superposition and offsetting effect of PEO and dodecyl side chains was observed. An enhancement in the interpenetration of counterion atmospheres as a result of side chains was also found. In addition, the rate constant ratio and the distance of counterion fluctuations perpendicular to the chains were estimated. It was demonstrated that the effects of side chains on the effective charges or ionization properties of GCP play an important role in their conformation, counterion distribution, and fluctuation.
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Affiliation(s)
- Xinlu Zhou
- College of Chemistry, Beijing Normal University, Beijing 100875, China.
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Martinez-Santiago J, Totland C, Ananthapadmanabhan KP, Tsaur L, Somasundaran P. The nature of fatty acid interaction with a polyelectrolyte-surfactant pair revealed by NMR spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:10197-10205. [PMID: 25109504 DOI: 10.1021/la5020708] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The interaction mechanisms of an oppositely charged polyelectrolyte-surfactant pair and dodecanoic (lauric) acid (LA) were experimentally investigated using a combination of nuclear magnetic resonance (NMR) techniques. It is observed that LA significantly affects the interaction between the anionic surfactant sodium dodecylethersulfate (SDES) and the cationic polymer guar modified with grafted hydroxypropyl trimethylammonium chloride (Jaguar C13 BF). Typically, oppositely charged polymers and surfactants interact electrostatically at a certain surfactant concentration known as the critical aggregation concentration (CAC). Once the polymer is neutralized by the surfactant, an insoluble complex (precipitate) is observed (phase separation), and, at concentrations beyond the surfactant critical micellar concentration (CMC'), the system returns to a one phase entity. In a system in which a mixture of SDES-LA is added to the polymer, NMR data show that below the neutralization onset, some of the polymer interacts with SDES, while some of the polymer is adsorbed at the surface of LA solid aggregates present in the system. Furthermore, SDES is found to aggregate in a lamellar-like structure at the polymer side chain prior to the SDES CMC'. Above the SDES (CMC'), LA is solubilized and incorporated at the palisade region of SDES micelles. Analysis of (1)H resonances provided estimated concentrations of all species in the system phases at all stages of interaction.
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Affiliation(s)
- Jose Martinez-Santiago
- NSF I/UCRC Center for Particulates and Surfactant Systems (CPaSS), Columbia University , New York, New York 10027, United States
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10
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Rongé J, Bosserez T, Martel D, Nervi C, Boarino L, Taulelle F, Decher G, Bordiga S, Martens JA. Monolithic cells for solar fuels. Chem Soc Rev 2014; 43:7963-81. [DOI: 10.1039/c3cs60424a] [Citation(s) in RCA: 166] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A tutorial review explaining the many processes occurring in photoelectrochemical cells for solar fuel production, and prospects for future developments.
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Affiliation(s)
- Jan Rongé
- KU Leuven
- Centre for Surface Chemistry and Catalysis
- B-3001 Leuven, Belgium
| | - Tom Bosserez
- KU Leuven
- Centre for Surface Chemistry and Catalysis
- B-3001 Leuven, Belgium
| | - David Martel
- University of Strasbourg
- Institut Charles Sadron
- F-67000 Strasbourg, France
| | - Carlo Nervi
- University of Torino
- Nanostructured Interfaces and Surfaces
- I-10135 Torino, Italy
| | - Luca Boarino
- Istituto Nazionale di Ricerca Metrologica
- I-10135 Torino, Italy
| | - Francis Taulelle
- KU Leuven
- Centre for Surface Chemistry and Catalysis
- B-3001 Leuven, Belgium
| | - Gero Decher
- University of Strasbourg
- Institut Charles Sadron
- F-67000 Strasbourg, France
| | - Silvia Bordiga
- University of Torino
- Nanostructured Interfaces and Surfaces
- I-10135 Torino, Italy
| | - Johan A. Martens
- KU Leuven
- Centre for Surface Chemistry and Catalysis
- B-3001 Leuven, Belgium
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Guzmán ML, Manzo RH, Olivera ME. Eudragit E100 as a drug carrier: the remarkable affinity of phosphate ester for dimethylamine. Mol Pharm 2012; 9:2424-33. [PMID: 22808998 DOI: 10.1021/mp300282f] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Therapeutic agents containing phosphate groups in their molecules have increasing therapeutic impact. The object of this study was to characterize the cationic polyelectrolyte Eudragit E100 (EuE100) as a carrier for drugs containing phosphate groups, using dexamethasone phosphate (DP) as a model. A series of EuE100-DP complexes was obtained by acid-base reaction in which DP neutralized 12.5-75% of the basic groups of EuE100. The solids obtained after solvent evaporation revealed by spectroscopic characterization the complete reaction between the components through the ionic interaction between the amine groups of EuE100 and the phosphate groups of DP. The reversibility of the counterion condensation, evaluated through the proton-withdrawing effect produced by the ionic exchange generated by titration with NaCl, showed a remarkable high affinity between EuE100 and DP. In line, drug delivery in bicompartimental Franz cells toward water as receptor medium was very slow (2% in 6 h). However, it was increased as water was replaced by NaCl solution, which upon diffusion generates ionic exchange. A sustained release of DP with noticeable zero order kinetics accounted for a remarkable high affinity, mainly due to the electrostatic attraction. The release rate remains constant regardless of the saline concentration of the media. Besides, the delivery control is maintained even in gastric simulated fluid, a property not informed previously for EuE100 complexes.
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Affiliation(s)
- M L Guzmán
- Department of Pharmacy, Faculty of Chemical Sciences, Pharmaceutical Technology Research Unit, National University of Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria (5000), Córdoba, Argentina
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Maki H, Miyajima T. Linear Charge Density Dependence of the Polyelectrolyte Phase Volume of Ionic Dextran Sulfate as a Strong Acidic Polyion. Macromolecules 2011. [DOI: 10.1021/ma200270r] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hideshi Maki
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyougo 657-8501, Japan
| | - Tohru Miyajima
- Department of Chemistry, Faculty of Science and Engineering, Saga University, 1-Honjo, Saga 840-8502, Japan
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Qiu X, Yang Y, Wang L, Lu S, Shao Z, Chen X. Synergistic interactions during thermosensitive chitosan-β-glycerophosphate hydrogel formation. RSC Adv 2011. [DOI: 10.1039/c1ra00149c] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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14
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Spiess HW. Interplay of Structure and Dynamics in Macromolecular and Supramolecular Systems. Macromolecules 2010. [DOI: 10.1021/ma1005952] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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