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Blanco PM, Narambuena CF, Madurga S, Mas F, Garcés JL. Unusual Aspects of Charge Regulation in Flexible Weak Polyelectrolytes. Polymers (Basel) 2023; 15:2680. [PMID: 37376324 DOI: 10.3390/polym15122680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 06/07/2023] [Accepted: 06/10/2023] [Indexed: 06/29/2023] Open
Abstract
This article reviews the state of the art of the studies on charge regulation (CR) effects in flexible weak polyelectrolytes (FWPE). The characteristic of FWPE is the strong coupling of ionization and conformational degrees of freedom. After introducing the necessary fundamental concepts, some unconventional aspects of the the physical chemistry of FWPE are discussed. These aspects are: (i) the extension of statistical mechanics techniques to include ionization equilibria and, in particular, the use of the recently proposed Site Binding-Rotational Isomeric State (SBRIS) model, which allows the calculation of ionization and conformational properties on the same foot; (ii) the recent progresses in the inclusion of proton equilibria in computer simulations; (iii) the possibility of mechanically induced CR in the stretching of FWPE; (iv) the non-trivial adsorption of FWPE on ionized surfaces with the same charge sign as the PE (the so-called "wrong side" of the isoelectric point); (v) the influence of macromolecular crowding on CR.
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Affiliation(s)
- Pablo M Blanco
- Physical Chemistry Unit, Materials Science and Physical Chemistry Department & Research Institute of Theoretical and Computational Chemistry (IQTCUB), Barcelona University (UB), 08028 Barcelona, Catalonia, Spain
| | - Claudio F Narambuena
- Grupo de Bionanotecnologia y Sistemas Complejos, Infap-CONICET & Facultad Regional San Rafael, Universidad Tecnológica Nacional, San Rafael 5600, Argentina
| | - Sergio Madurga
- Physical Chemistry Unit, Materials Science and Physical Chemistry Department & Research Institute of Theoretical and Computational Chemistry (IQTCUB), Barcelona University (UB), 08028 Barcelona, Catalonia, Spain
| | - Francesc Mas
- Physical Chemistry Unit, Materials Science and Physical Chemistry Department & Research Institute of Theoretical and Computational Chemistry (IQTCUB), Barcelona University (UB), 08028 Barcelona, Catalonia, Spain
| | - Josep L Garcés
- Chemistry Department, Technical School of Agricultural Engineering & AGROTECNIO, Lleida University (UdL), 25003 Lleida, Catalonia, Spain
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Blanco PM, Madurga S, Mas F, Garcés JL. Coupling of Charge Regulation and Conformational Equilibria in Linear Weak Polyelectrolytes: Treatment of Long-Range Interactions via Effective Short-Ranged and pH-Dependent Interaction Parameters. Polymers (Basel) 2018; 10:E811. [PMID: 30960736 PMCID: PMC6403780 DOI: 10.3390/polym10080811] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 07/17/2018] [Accepted: 07/23/2018] [Indexed: 01/26/2023] Open
Abstract
The classical Rotational Isomeric State (RIS) model, originally proposed by Flory, has been used to rationalize a wide range of physicochemical properties of neutral polymers. However, many weak polyelectrolytes of interest are able to regulate their charge depending on the conformational state of the bonds. Recently, it has been shown that the RIS model can be coupled with the Site Binding (SB) model, for which the ionizable sites can adopt two states: protonated or deprotonated. The resulting combined scheme, the SBRIS model, allows for analyzing ionization and conformational equilibria on the same foot. In the present work, this approach is extended to include pH-dependent electrostatic Long-Range (LR) interactions, ubiquitous in weak polyelectrolytes at moderate and low ionic strengths. With this aim, the original LR interactions are taken into account by defining effective Short-Range (SR) and pH-dependent parameters, such as effective microscopic protonation constants and rotational bond energies. The new parameters are systematically calculated using variational methods. The machinery of statistical mechanics for SR interactions, including the powerful and fast transfer matrix methods, can then be applied. The resulting technique, which we will refer to as the Local Effective Interaction Parameters (LEIP) method, is illustrated with a minimal model of a flexible linear polyelectrolyte containing only one type of rotating bond. LEIP reproduces very well the pH dependence of the degree of protonation and bond probabilities obtained by semi-grand canonical Monte Carlo simulations, where LR interactions are explicitly taken into account. The reduction in the computational time in several orders of magnitude suggests that the LEIP technique could be useful in a range of areas involving linear weak polyelectrolytes, allowing direct fitting of the relevant physical parameters to the experimental quantities.
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Affiliation(s)
- Pablo M Blanco
- Physical Chemistry Unit, Department of Materials Science and Physical Chemistry & Research Institute of Theoretical and Computational Chemistry (IQTCUB) of Barcelona University (UB), 08028 Barcelona, Catalonia, Spain.
| | - Sergio Madurga
- Physical Chemistry Unit, Department of Materials Science and Physical Chemistry & Research Institute of Theoretical and Computational Chemistry (IQTCUB) of Barcelona University (UB), 08028 Barcelona, Catalonia, Spain.
| | - Francesc Mas
- Physical Chemistry Unit, Department of Materials Science and Physical Chemistry & Research Institute of Theoretical and Computational Chemistry (IQTCUB) of Barcelona University (UB), 08028 Barcelona, Catalonia, Spain.
| | - Josep L Garcés
- Department of Chemistry, Technical School of Agricultural Engineering & Agrotecnio of Lleida University (UdL), 25003 Lleida, Catalonia, Spain.
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Calzaferri G. Entropy in multiple equilibria, theory and applications. Phys Chem Chem Phys 2017; 19:10611-10621. [DOI: 10.1039/c7cp00584a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Entropy controls the dependence of the equilibrium constants in the synthesis of host–guest composites on the occupation rc for channels of different length.
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Affiliation(s)
- Gion Calzaferri
- Department of Chemistry and Biochemistry
- 3012 Bern
- Switzerland
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Garcés JL, Madurga S, Rey-Castro C, Mas F. Dealing with long-range interactions in the determination of polyelectrolyte ionization properties. Extension of the transfer matrix formalism to the full range of ionic strengths. ACTA ACUST UNITED AC 2016. [DOI: 10.1002/polb.24269] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Josep L. Garcés
- Chemistry Department; Technical School of Agricultural Engineering & AGROTECNIO of Lleida University (UdL); Lleida Catalonia Spain
| | - Sergio Madurga
- Physical Chemistry Unit; Materials Science and Physical Chemistry Department & Research Institute of Theoretical and Computational Chemistry (IQTCUB) of Barcelona University (UB); Barcelona Catalonia Spain
| | - Carlos Rey-Castro
- Chemistry Department; Technical School of Agricultural Engineering & AGROTECNIO of Lleida University (UdL); Lleida Catalonia Spain
| | - Francesc Mas
- Physical Chemistry Unit; Materials Science and Physical Chemistry Department & Research Institute of Theoretical and Computational Chemistry (IQTCUB) of Barcelona University (UB); Barcelona Catalonia Spain
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Domingos RF, Franco C, Pinheiro JP. The role of charged polymer coatings of nanoparticles on the speciation and fate of metal ions in the environment. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:2900-2906. [PMID: 25220770 DOI: 10.1007/s11356-014-3546-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 09/01/2014] [Indexed: 06/03/2023]
Abstract
Determining the environmental risk of metals requires an in-depth understanding of the environmental matrices composition, which currently also includes the presence of manufactured metallic nanoparticles (NPs) usually, stabilized by a polymer surface coating. As a consequence, is necessary to take into account effects of the NP core, the polymer surface coating and their mutual interaction as well as with other environmental components. The release of metal ions from metallic NPs is a well-known outcome, however, the effect of the presence of the NP polymer coating in the NPs solubilization mechanism is not well understood. In this study the dynamic speciation of Cd and Pb in presence of a polyacrylic acid (PAA)-stabilized CdTe/CdS NP was quantified by scanned stripping chronopotentiometry (SSCP). It was found that although the NP solubility was 5.8× larger at pH 8.5 than at pH 6.0, the amount of free Cd ions was much smaller (2.4 % at pH 8.5 vs. 57 % at pH 6.0). The concentration of free Cd and Pb ions in solution was larger in presence of the PAA-shells than when in presence of the same amount of polymer but when this is at the surface of the NP. This effect is attributed to the metal ions interaction with the particle itself. The effect is notably larger for Pb ions and might results from the exchange of Cd by Pb ions at the particle surface since PbS is less soluble than CdS.
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Affiliation(s)
- Rute F Domingos
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Torre Sul lab 11-6.3, Av. Rovisco Pais # 1, 1049-001, Lisbon, Portugal,
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Domingos RF, Franco C, Pinheiro JP. Stability of core/shell quantum dots--role of pH and small organic ligands. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2013; 20:4872-4880. [PMID: 23307080 DOI: 10.1007/s11356-012-1457-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 12/27/2012] [Indexed: 06/01/2023]
Abstract
The improvement of knowledge about the toxicity and even processability, and stability of quantum dots (QD) requires the understanding of the relationship between the QD binding head group, surface structure, and interligand interaction. The scanned stripping chronopotentiometry and absence of gradients and Nernstian equilibrium stripping techniques were used to determine the concentration of Cd dissolved from a polyacrylate-stabilized CdTe/CdS QD. The effects of various concentrations of small organic ligands such as citric acid, glycine, and histidine and the roles of pH (4.5-8.5) and exposure time (0-48 h) were evaluated. The highest QD dissolution was obtained at the more acidic pH in absence of the ligands (52%) a result of the CdS shell solubility. At pH 8.5 the largest PAA ability to complex the dissolved Cd leads to a further QD solubility until the equilibrium is reached (24% of dissolved Cd vs. 4% at pH 6.0). The citric acid presence resulted in greater QD dissolution, whereas glycine, an amino acid, acts against QD dissolution. Surprisingly, the presence of histidine, an amino acid with an imidazole functional group, leads to the formation of much strong Cd complexes over time, which may be non-labile, inducing variations in the local environment of the QD surface.
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Affiliation(s)
- Rute F Domingos
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade Técnica de Lisboa, Torre Sul lab 11-6.3, Av. Rovisco Pais # 1, 1049-001 Lisbon, Portugal.
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Lluís Garcés J, Rey-Castro C, David C, Madurga S, Mas F, Pastor I, Puy J. Model-Independent Link between the Macroscopic and Microscopic Descriptions of Multidentate Macromolecular Binding: Relationship between Stepwise, Intrinsic, and Microscopic Equilibrium Constants. J Phys Chem B 2009; 113:15145-55. [DOI: 10.1021/jp9041815] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Josep Lluís Garcés
- Departament de Química, Universitat de Lleida (UdL), Av. Rovira Roure, 191 E-25198 Lleida, Spain, EU, and Physical Chemistry Department & Theoretical and Computational Chemistry (IQTCUB), Universitat de Barcelona (UB), C/ Martí i Franquès, 1 E-08028 Barcelona, Spain, EU
| | - Carlos Rey-Castro
- Departament de Química, Universitat de Lleida (UdL), Av. Rovira Roure, 191 E-25198 Lleida, Spain, EU, and Physical Chemistry Department & Theoretical and Computational Chemistry (IQTCUB), Universitat de Barcelona (UB), C/ Martí i Franquès, 1 E-08028 Barcelona, Spain, EU
| | - Calin David
- Departament de Química, Universitat de Lleida (UdL), Av. Rovira Roure, 191 E-25198 Lleida, Spain, EU, and Physical Chemistry Department & Theoretical and Computational Chemistry (IQTCUB), Universitat de Barcelona (UB), C/ Martí i Franquès, 1 E-08028 Barcelona, Spain, EU
| | - Sergio Madurga
- Departament de Química, Universitat de Lleida (UdL), Av. Rovira Roure, 191 E-25198 Lleida, Spain, EU, and Physical Chemistry Department & Theoretical and Computational Chemistry (IQTCUB), Universitat de Barcelona (UB), C/ Martí i Franquès, 1 E-08028 Barcelona, Spain, EU
| | - Francesc Mas
- Departament de Química, Universitat de Lleida (UdL), Av. Rovira Roure, 191 E-25198 Lleida, Spain, EU, and Physical Chemistry Department & Theoretical and Computational Chemistry (IQTCUB), Universitat de Barcelona (UB), C/ Martí i Franquès, 1 E-08028 Barcelona, Spain, EU
| | - Isabel Pastor
- Departament de Química, Universitat de Lleida (UdL), Av. Rovira Roure, 191 E-25198 Lleida, Spain, EU, and Physical Chemistry Department & Theoretical and Computational Chemistry (IQTCUB), Universitat de Barcelona (UB), C/ Martí i Franquès, 1 E-08028 Barcelona, Spain, EU
| | - Jaume Puy
- Departament de Química, Universitat de Lleida (UdL), Av. Rovira Roure, 191 E-25198 Lleida, Spain, EU, and Physical Chemistry Department & Theoretical and Computational Chemistry (IQTCUB), Universitat de Barcelona (UB), C/ Martí i Franquès, 1 E-08028 Barcelona, Spain, EU
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Xing S, Xu H, Shi G, Chen J, Zeng L, Jin L. A Simple and Sensitive Method for the Amperometric Detection of Trace Chromium(VI) Based on Prussian Blue Modified Glassy Carbon Electrode. ELECTROANAL 2009. [DOI: 10.1002/elan.200904594] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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