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Delgado MZ, Aranda FL, Hernandez-Tenorio F, Garrido-Miranda KA, Meléndrez MF, Palacio DA. Polyelectrolytes for Environmental, Agricultural, and Medical Applications. Polymers (Basel) 2024; 16:1434. [PMID: 38794627 PMCID: PMC11124962 DOI: 10.3390/polym16101434] [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: 03/13/2024] [Revised: 04/25/2024] [Accepted: 04/26/2024] [Indexed: 05/26/2024] Open
Abstract
In recent decades, polyelectrolytes (PELs) have attracted significant interest owing to a surge in research dedicated to the development of new technologies and applications at the biological level. Polyelectrolytes are macromolecules of which a substantial portion of the constituent units contains ionizable or ionic groups. These macromolecules demonstrate varied behaviors across different pH ranges, ionic strengths, and concentrations, making them fascinating subjects within the scientific community. The aim of this review is to present a comprehensive survey of the progress in the application studies of polyelectrolytes and their derivatives in various fields that are vital for the advancement, conservation, and technological progress of the planet, including agriculture, environmental science, and medicine. Through this bibliographic review, we seek to highlight the significance of these materials and their extensive range of applications in modern times.
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Affiliation(s)
- Martina Zuñiga Delgado
- Departamento de Polímeros, Facultad de Ciencias Químicas, Universidad de Concepción, Edmundo Larenas 129, Casilla 160-C, Concepción 4070409, Chile (F.L.A.)
| | - Francisca L. Aranda
- Departamento de Polímeros, Facultad de Ciencias Químicas, Universidad de Concepción, Edmundo Larenas 129, Casilla 160-C, Concepción 4070409, Chile (F.L.A.)
- Department of Materials Engineering (DIMAT), Faculty of Engineering, University of Concepcion, 270 Edmundo Larenas, Box 160-C, Concepcion 4070409, Chile
| | - Fabian Hernandez-Tenorio
- Environmental Processes Research Group, School of Applied Sciences and Engineering, Universidad EAFIT, Medellin 050022, Colombia;
| | - Karla A. Garrido-Miranda
- Scientific and Technological Bioresource Nucleus (BIOREN-UFRO), Universidad de La Frontera, Temuco 4780000, Chile;
| | - Manuel F. Meléndrez
- Facultad de Ciencias para el Cuidado de la Salud, Universidad San Sebastián, Campus Las Tres Pascuales, Lientur 1457, Concepción 4060000, Chile
| | - Daniel A. Palacio
- Departamento de Polímeros, Facultad de Ciencias Químicas, Universidad de Concepción, Edmundo Larenas 129, Casilla 160-C, Concepción 4070409, Chile (F.L.A.)
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Tagliabue A, Micheletti C, Mella M. Effect of Counterion Size on Knotted Polyelectrolyte Conformations. J Phys Chem B 2024; 128:4183-4194. [PMID: 38648610 DOI: 10.1021/acs.jpcb.3c07446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Using Langevin dynamics simulations and a coarse-grained primitive model of electrolytes, we show that the behavior of knotted circular strong polyelectrolytes (PEs) in diluted aqueous solution is largely affected by the diameter of the counterions (CIs), σCI. Indeed, we observe that both gyration radius and knot length vary nonmonotonically with σCI, with both small and bulky CIs favoring knot localization, while medium-sized ones promote delocalized knots. We also show that the conformational change from delocalized to tight knots occurs via the progressive coalescence of the knot's essential crossings. The emerging conformers correspond to the minima of the free energy landscape profiled as a function of the knot length or PE size. We demonstrate that different conformational states can coexist, the transition between them appearing first-order-like and controlled by the enthalpic and entropic trade-off of the amount of CIs condensed on the PE. Such balance can be further altered by varying CI concentrations, thus providing an additional and more convenient tuning parameter for the system properties. Our results lay the foundation for achieving broader and more precise external adjustability of knotted PE size and shape by choosing the nature of its CIs. Thus, they offer new intriguing possibilities for designing novel PE-based materials that are capable of responding to changes in ionic solution properties.
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Affiliation(s)
- Andrea Tagliabue
- Dipartimento di Scienza ed Alta Tecnologia, Università degli Studi dell'Insubria, via Valleggio 11, Como 22100, Italy
- SISSA (Scuola Internazionale Superiore di Studi Avanzati), via Bonomea 265, Trieste 34136, Italy
| | - Cristian Micheletti
- SISSA (Scuola Internazionale Superiore di Studi Avanzati), via Bonomea 265, Trieste 34136, Italy
| | - Massimo Mella
- Dipartimento di Scienza ed Alta Tecnologia, Università degli Studi dell'Insubria, via Valleggio 11, Como 22100, Italy
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3
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Ghosh S, Kundagrami A. Effect of counterion size on polyelectrolyte conformations and thermodynamics. J Chem Phys 2024; 160:084909. [PMID: 38421069 DOI: 10.1063/5.0178233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 02/05/2024] [Indexed: 03/02/2024] Open
Abstract
We present a theoretical model to study the effect of counterion size on the effective charge, size, and thermodynamic behavior of a single, isolated, and flexible polyelectrolyte (PE) chain. We analyze how altering counterion size modifies the energy and entropy contributions to the system, including the ion-pair free energy, excluded volume interactions, entropy of free and condensed ions, and dipolar attraction among monomer-counterion pairs, which result in competing effects challenging intuitive predictions. The PE self-energy is calculated using the Edwards-Muthukumar Hamiltonian, considering a Gaussian monomer distribution for the PE. The condensed ions are assumed to be confined within a cylindrical volume around the PE backbone. The dipolar and excluded volume interactions are described by the second and third virial coefficients. The assumption of freely rotating dipoles results in a first-order coil-globule transition of the PE chain. A more realistic, weaker dipolar attraction, parameterized in our theory, shifts it to a second-order continuous transition. We calculate the size scaling-exponent of the PE and find exponents according to the relative dominance of the electrostatic, excluded volume, or dipolar effects. We further identify the entropy- and energy-driven regimes of the effective charge and conformation of the PE, highlighting the interplay of free ion entropy and ion-pair energy with varying electrostatic strengths. The crossover strength, dependent on the counterion size, indicates that diminishing sizes favor counterion condensation at the expense of free ion entropy. The predictions of the model are consistent with trends in simulations and generalize the findings of the point-like counterion theories.
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Affiliation(s)
- Souradeep Ghosh
- Deparment of Physical Sciences and Centre for Advanced Functional Materials, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India
| | - Arindam Kundagrami
- Deparment of Physical Sciences and Centre for Advanced Functional Materials, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India
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Malhotra I, Potoyan DA. Re-entrant transitions of locally stiff RNA chains in the presence of polycations leads to gelated architectures. SOFT MATTER 2023. [PMID: 37449795 PMCID: PMC10369498 DOI: 10.1039/d3sm00320e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/18/2023]
Abstract
The liquid-liquid phase separation of protein and nucleic acid mixtures drives the formation of numerous membraneless compartments in cells. Temperature variation is commonly used for mapping condensate phase diagrams, which often display unique upper critical temperatures. Recent report on peptide-RNA mixtures has shown the existence of lower and upper critical solution temperatures, highlighting the importance of temperature-dependent solvent and ion-mediated forces. In the present work, we employ residue-level coarse-grained models of RNA and polycation peptide chains for simulating temperature-induced re-entrant transitions and shedding light on the role played by mobile ions, temperature-dependent dielectric permittivity, and local chain stiffness. We show that differences in bending rigidity can significantly modulate condensate topology leading to the formation of gelated or fibril like architectures. The study also finds that temperature dependence of water permittivity is generally sufficient for recapitulating experimentally observed closed loop and LCST phase diagrams of highly charged protein-RNA mixtures. However, we find that similar-looking closed-loop phase diagrams can correspond to vastly different condensate topologies.
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Affiliation(s)
- Isha Malhotra
- Department of Chemistry, Iowa State University, Ames, Iowa 50014, USA.
| | - Davit A Potoyan
- Department of Chemistry, Iowa State University, Ames, Iowa 50014, USA.
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5
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Gavrilov AA. Effect of the counterion size on microphase separation in charged-neutral diblock copolymers. J Chem Phys 2023; 158:054901. [PMID: 36754807 DOI: 10.1063/5.0134164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
In this work, the question of the influence of the counterion size on the self-assembly in melts of diblock copolymers with one charged block was studied using coarse-grained molecular dynamics simulations. It was assumed that the blocks were fully compatible, i.e., the Flory-Huggins parameter χ between them was equal to 0. Due to the presence of correlation attraction (electrostatic cohesion) between the charged species, the systems with all types of counterions underwent transitions to ordered states, forming various morphologies, including lamellae, perforated lamellae, and hexagonally packed cylinders. Phase diagrams were constructed by varying the chain composition fc and locating the order-disorder transition positions in terms of the electrostatic strength parameter λ (dimensionless Bjerrum length). Despite having a rather large ion size mismatch, the systems with smaller counterions demonstrated an even better tendency to form microphase separated states than the systems with larger ones. It was found that the differences between the phase diagrams of the systems with different counterions can be roughly rationalized by using coordinates (volume fraction of the charged block φc-modified interaction parameter λ*). The latter parameter assumes that the electrostatic energy is simply inversely proportional to the characteristic distance between the ions of different signs. Such an approach appeared to be rather effective and allowed the diagrams obtained for different counterion sizes to almost coincide. The results of this work suggest that the counterion size can be used as a tool to control the system morphology as well as the effective incompatibility between the blocks.
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Affiliation(s)
- Alexey A Gavrilov
- Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia and A.N. Nesmeyanov Institute of Organoelement Compounds Russian Academy of Sciences (INEOS RAS), 119991 Moscow, Russia
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6
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Radhakrishnan K, Singh SP. Explicit characterization of counterion dynamics around a flexible polyelectrolyte. Phys Rev E 2022; 105:044501. [PMID: 35590562 DOI: 10.1103/physreve.105.044501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 03/04/2022] [Indexed: 06/15/2023]
Abstract
The article presents a comprehensive study of counterion dynamics around a generic linear polyelectrolyte chain with the help of coarse-grained computer simulations. The ion-chain coupling is discussed in the form of binding time, mean-square displacement (MSD) relative to the chain, local ion transport coefficient, and spatiotemporal correlations in the effective charge. We have shown that a counterion exhibits subdiffusive behavior 〈δR^{2}〉∼t^{δ}, δ≈0.9 w.r.t. chain's center of mass. The MSD of ions perpendicularly outward from the chain segment exhibits a smaller subdiffusive exponent compared to the one along the chain backbone. The effective diffusivity of ion is the lowest in chain's close proximity, extending up to the length-scale of radius of gyration R_{g}. Beyond R_{g} at larger distances, they attain diffusivity of free ion with a smooth cross-over from the adsorbed regime to the free ion regime. We have shown that the effective diffusivity drastically decreases for the multivalent ions, while the crossover length scale remains the same. Conversely, with increasing salt concentration the coupling-length scale reduces, while the diffusivity remains unaltered. The effective diffusivity of adsorbed-ion reveals an exponential reduction with electrostatic interaction strength. We further corroborate this from the binding time of ions on the chain, which also grows exponentially with the coupling strength of the ion-polymer duo. Moreover, the binding time of ions exhibits a weak dependence with salt concentration for the monovalent salt, while for multivalent salts the binding time decreases dramatically with concentration. Our work also elucidates fluctuations in the effective charge per site, where it exhibits strong negative correlations at short length-scales.
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Affiliation(s)
- Keerthi Radhakrishnan
- Department of Physics, Indian Institute of Science Education and Research, Bhopal 462 066, Madhya Pradesh, India
| | - Sunil P Singh
- Department of Physics, Indian Institute of Science Education and Research, Bhopal 462 066, Madhya Pradesh, India
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7
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Formation, structure, properties of chitosan aspartate and metastable state of its solutions for obtaining nanoparticles. Carbohydr Polym 2022; 277:118773. [PMID: 34893217 DOI: 10.1016/j.carbpol.2021.118773] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 09/29/2021] [Accepted: 10/04/2021] [Indexed: 02/02/2023]
Abstract
Chitosan (200 kDa) dissolution in an aqueous solution of L-aspartic acid, physicochemical properties and features of the resulting chitosan salt were studied by conductometry, potentiometry, viscometry, turbidimetry, IR and NMR spectroscopy, and X-ray diffractometry. Chitosan aspartate is a water-soluble hydrated polymorph exhibiting properties of a cationic polyelectrolyte with an effective macromolecular coil radius 60-75 nm. The specific conductivity, dielectric constant, viscosity and pH of the chitosan - L-aspartic acid - water system change over time after preparation due to counterion-polycation association to form ion pairs, multiplet structures, and their subsequent aggregation. As a result, nanoparticles (40-90 nm) are formed after ~24 h, microparticles (0.6-1.4 μm) are after ~48 h, and precipitation occurs after 72-96 h. The precipitated phase is a water-insoluble chitosan salt with a developed system of H-bonds and high crystallinity degree. Chitosan nanoparticles have high biocompatibility and the ability to accelerate the proliferative activity of epithelial cells. HYPOTHESIS: Ion pairs and multiplets are formed in the chitosan - L-aspartic acid - water system due to counterion association, which leads to phase segregation of the polymer substance at the level of nanoparticles and microparticles.
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Lezov A, Rogozhin V, Donets A, Lezova A, Gubarev A, Vlasov P, Samokhvalova S, Polushina G, Polushin S, Tsvetkov N. Influence of anions on behavior of cationic polyelectrolyte poly(diallyldimethylammonium chloride) and its copolymer in aqueous solutions. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.118369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Gordievskaya YD, Kramarenko EY, Gavrilov AA. The effect of explicit polarity on the conformational behavior of a single polyelectrolyte chain. Phys Chem Chem Phys 2021; 23:26296-26305. [PMID: 34787619 DOI: 10.1039/d1cp03167h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In this work using dissipative particle dynamics simulations with explicit treatment of polar species we demonstrate that the molecular nature of dielectric media has a significant impact on swelling and collapse of a polyelectrolyte chain in a dilute solution. We show that the small-scale effects related to the presence of polar species lead to the intensification of the electrostatic interactions when the charges are close to each other and/or their density is high enough. As a result, the electrostatic strength , usually regarded as the main parameter governing the polyelectrolyte chain collapse, does not have a universal meaning: the value of λ at which the coil-to-globule transition occurs is found to be dependent on the specific fixed value of the solvent bulk permittivity ε while varying the monomer unit charge Q and vice versa. This effect is observed even when the backbone and the counterions have the same polarity as the solvent beads, i.e. no dielectric mismatch is present. The reason for such behavior is rationalized in terms of the "effective" dielectric permittivity εeff which depends on the volume fraction φ of charged units inside the polymer chain volume; using εeff instead of ε collapses all data onto one master curve describing the chain shrinking with λ. Furthermore, it is shown that a polar chain adopts less swollen conformations in the polyelectrolyte regime and collapses more easily compared to a non-polar chain.
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Affiliation(s)
- Yulia D Gordievskaya
- Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia. .,A. N. Nesmeyanov Institute of Organoelement Compounds RAS, 119991 Moscow, Russia
| | - Elena Yu Kramarenko
- Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia. .,A. N. Nesmeyanov Institute of Organoelement Compounds RAS, 119991 Moscow, Russia
| | - Alexey A Gavrilov
- Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia.
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10
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Pial TH, Sachar HS, Das S. Quantification of Mono- and Multivalent Counterion-Mediated Bridging in Polyelectrolyte Brushes. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00328] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Turash Haque Pial
- Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20742, United States
| | - Harnoor Singh Sachar
- Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20742, United States
| | - Siddhartha Das
- Department of Mechanical Engineering, University of Maryland, College Park, Maryland 20742, United States
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11
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Spatial segregation of mixed-sized counterions in dendritic polyelectrolytes. Sci Rep 2021; 11:8108. [PMID: 33854111 PMCID: PMC8046808 DOI: 10.1038/s41598-021-87448-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 03/30/2021] [Indexed: 11/08/2022] Open
Abstract
Langevin dynamics simulations are utilized to study the structure of a dendritic polyelectrolyte embedded in two component mixtures comprised of conventional (small) and bulky counterions. We vary two parameters that trigger conformational properties of the dendrimer: the reduced Bjerrum length, [Formula: see text], which controls the strength of electrostatic interactions and the number fraction of the bulky counterions, [Formula: see text], which impacts on their steric repulsion. We find that the interplay between the electrostatic and the counterion excluded volume interactions affects the swelling behavior of the molecule. As compared to its neutral counterpart, for weak electrostatic couplings the charged dendrimer exists in swollen conformations whose size remains unaffected by [Formula: see text]. For intermediate couplings, the absorption of counterions into the pervaded volume of the dendrimer starts to influence its conformation. Here, the swelling factor exhibits a maximum which can be shifted by increasing [Formula: see text]. For strong electrostatic couplings the dendrimer deswells correspondingly to [Formula: see text]. In this regime a spatial separation of the counterions into core-shell microstructures is observed. The core of the dendrimer cage is preferentially occupied by the conventional ions, whereas its periphery contains the bulky counterions.
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12
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Gordievskaya YD, Kramarenko EY. Conformational transitions and helical structures of a dipolar chain in external electric fields. SOFT MATTER 2021; 17:1376-1387. [PMID: 33325981 DOI: 10.1039/d0sm01868f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The conformational behavior of a single dipolar chain in a uniform electric field is investigated by molecular dynamics simulations. The dipolar chain is modeled as a backbone bead-on-spring chain of equally charged beads, each connected by a rigid spring with an oppositely charged side bead that can freely rotate around the backbone bead. In the strong coupling regime, when the dipolar chain is in the globular state due to a strong electrostatic correlational attraction, the application of an electric field causes the chain swelling and elongation along the field direction. In the weak coupling regime, a qualitatively new regime is found when the swollen dipolar chain shrinks along the field direction adopting flattened conformations due to the field-induced anisotropy of the chain rigidity and the head-to-tail attraction of the dipoles orienting along the field lines. A novel helical conformation is detected for low-polar media and strong electric fields. An increasing rigidity of the backbone chain leads to some stabilization of the helical conformation and the formation of double and triple helices as well as flat spread springs. Fine tuning of the interplay between dipolar and volume interactions by external electric fields induces re-orientation of rod-like dipolar chains in dilute solutions. The obtained results can provide new ways to control dipolar polymer conformations and design materials with responsive properties.
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Affiliation(s)
- Yulia D Gordievskaya
- Faculty of Physics, Lomonosov Moscow State University, Leninskie gory, 1-2, 119991, Moscow, Russia. and A. N. Nesmeyanov Institute of Organoelement Compounds RAS, Vavilova St., 28, 119991, Moscow, Russia
| | - Elena Yu Kramarenko
- Faculty of Physics, Lomonosov Moscow State University, Leninskie gory, 1-2, 119991, Moscow, Russia. and A. N. Nesmeyanov Institute of Organoelement Compounds RAS, Vavilova St., 28, 119991, Moscow, Russia
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13
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Affiliation(s)
- J. S. Kłos
- Faculty of Physics, A. Mickiewicz University, Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland
- Leibniz Institute of Polymer Research Dresden e.V., 01069 Dresden, Germany
| | - J. Paturej
- Institute of Physics, University of Silesia, 75 Pułku Piechoty 1, 41-500 Chorzów, Poland and
- Leibniz Institute of Polymer Research Dresden e.V., 01069 Dresden, Germany
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14
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Gordievskaya YD, Kramarenko EY. Effect of the Fraction and Size of Polar Groups on the Formation of Compact Conformations of a Polymer Chain with Variable Stiffness in Low-Polar Media. POLYMER SCIENCE SERIES B 2019. [DOI: 10.1134/s1560090419060046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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15
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Gordievskaya YD, Kramarenko EY. Conformational behavior of a semiflexible dipolar chain with a variable relative size of charged groups via molecular dynamics simulations. SOFT MATTER 2019; 15:6073-6085. [PMID: 31310250 DOI: 10.1039/c9sm00909d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The conformational behavior of an isolated semiflexible dipolar chain has been studied by molecular dynamics simulations. The dipolar chain was modeled as a backbone chain of charged beads, each containing an oppositely charged unit connected to it by a rigid spring. The main focus was on the effect of the backbone chain rigidity and the size of the charged groups on the morphology of the collapsed states of the chain formed in low-polar media where the electrostatic interactions are essential. It has been found that the stable globular conformations of the long chain of N = 256 backbone beads are a toroid and an elliptical globule. The macroscopic parameters (such as the radius of gyration and shape factors) as well as the local characteristics of these conformations (radial density distributions of ions, orientational correlations of chain segments, dipoles etc.) are studied depending on the chain stiffness. The regions of stability of a torus and an elliptical globule are found for the dipolar chains with variable dipole length and stiffness, which depend on the strength of electrostatic interactions. It has been shown that a size asymmetry of oppositely charged beads destabilizes globular states favoring elongated chain conformations. A coexistence of various metastable states was demonstrated for shorter chains of N = 128, 64, and 32.
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Affiliation(s)
- Yulia D Gordievskaya
- Faculty of Physics, Lomonosov Moscow State University, Leninskie gory, 1-2, 119991, Moscow, Russia. and A. N. Nesmeyanov Institute of Organoelement Compounds RAS, Vavilova St., 28, 119991, Moscow, Russia
| | - Elena Yu Kramarenko
- Faculty of Physics, Lomonosov Moscow State University, Leninskie gory, 1-2, 119991, Moscow, Russia. and A. N. Nesmeyanov Institute of Organoelement Compounds RAS, Vavilova St., 28, 119991, Moscow, Russia
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16
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Gavrilov AA, Chertovich AV, Potemkin II. Phase Behavior of Melts of Diblock-Copolymers with One Charged Block. Polymers (Basel) 2019; 11:E1027. [PMID: 31185691 PMCID: PMC6630698 DOI: 10.3390/polym11061027] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 06/05/2019] [Accepted: 06/08/2019] [Indexed: 02/05/2023] Open
Abstract
In this work, we investigated the phase behavior of melts of block-copolymers with one charged block by means of dissipative particle dynamics with explicit electrostatic interactions. We assumed that all the Flory-Huggins χ parameters were equal to 0. We showed that the charge- correlation attraction solely can cause microphase separation with a long-range order; a phase diagram was constructed by varying the volume fraction of the uncharged block and the electrostatic interaction parameter λ (dimensionless Bjerrum length). The obtained phase diagram was compared to the phase diagram of "equivalent" neutral diblock-copolymers with the non-zero χ-parameter between the beads of different blocks. The neutral copolymers were constructed by grafting the counterions to the corresponding co-ions of the charged block with further switching off the electrostatic interactions. Surprisingly, the differences between these phase diagrams are rather subtle; the same phases in the same order are observed, and the positions of the order-disorder transition ODT points are similar if the λ-parameter is considered as an "effective" χ-parameter. Next, we studied the position of the ODT for lamellar structure depending on the chain length N. It turned out that while for the uncharged diblock copolymer the product χcrN was almost independent of N, for the diblock copolymers with one charged block we observed a significant increase in λcrN upon increasing N. This can be attributed to the fact that the counterion entropy prevents the formation of ordered structures, and its influence is more pronounced for longer chains since they undergo the transition to ordered structures at smaller values of λ, when the electrostatic energy becomes comparable to kbT. This was supported by studying the ODT in diblock-copolymers with charged blocks and counterions cross-linked to the charged monomer units. The ODT for such systems was observed at significantly lower values of λ, with the difference being more pronounced at longer chain lengths N. The fact that the microphase separation is observed even at zero Flory-Huggins parameter can be used for the creation of "high-χ" copolymers: The incorporation of charged groups (for example, ionic liquids) can significantly increase the segregation strength. The diffusion of counterions in the obtained ordered structures was studied and compared to the case of a system with the same number of charged groups but a homogeneous structure; the diffusion coefficient along the lamellar plane was found to be higher than in any direction in the homogeneous structure.
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Affiliation(s)
- Alexey A Gavrilov
- Physics Department, Lomonosov Moscow State University, 119991 Moscow, Russia.
| | - Alexander V Chertovich
- Physics Department, Lomonosov Moscow State University, 119991 Moscow, Russia.
- Semenov Institute of Chemical Physics, 119991 Moscow, Russia.
| | - Igor I Potemkin
- Physics Department, Lomonosov Moscow State University, 119991 Moscow, Russia.
- DWI - Leibniz Institute for Interactive Materials, 52056 Aachen, Germany.
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17
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Liu LY, Xia G, Feng ZJ, Hao QH, Tan HG. Self-assembly of polyelectrolyte diblock copolymers at monovalent and multivalent counterions. SOFT MATTER 2019; 15:3689-3699. [PMID: 30888010 DOI: 10.1039/c9sm00028c] [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
In this work, the self-assembly behaviors of diblock copolymers consisting of one hydrophobic block and one ionizable polyelectrolyte (PE) block in the presence of monovalent and multivalent counterions are systematically discussed through molecular dynamics simulation. Copolymers are molded as bead-spring chains and the ions are explicitly considered. First, the self-assembled structures of symmetrical block copolymers at different charge fractions are analyzed in detail. Spherical hydrophobic cores are favored by all of the micelles. The effect of counterion valence is much more noticeable at high values of charge fraction. When the PE blocks are fully charged, the presence of multivalent counterions preferably provokes the formation of macroscopic structures. A precipitant spherical micelle is generated in the presence of divalent counterions. Special shapes of coronas are created in the presence of trivalent ions, and a remarkable one dimensional macroscopic cylindrical aggregation of micelles forms; the whole assembly is not typical core-shell micelles, but rather a cylinder with alternating spherical micelles arranged perpendicular to the cylinder axis. The self-assemblies with different lengths of fully charged PE blocks are also discussed. Surprisingly, in the presence of divalent counterions, two dimensional in-plane macroscopic aggregation of micelles is realized when the proportion of PE blocks is larger than 1/2; the self-assembled spherical micelles locate approximately in the same plane to form an inter-linked network. One dimensional aggregation of micelles in the presence of trivalent counterions is maintained with an increased proportion of the PE block. Owing to the dominant intra- and inter-condensation of divalent and trivalent counterions, respectively, two and one dimensional macroscopic aggregation of the micelles is achieved. Our findings indicate that varying the counterion valence is a powerful mechanism to tune the properties of self-assemblies, and the bridging effect introduced by multivalent counterions is the key parameter for the aggregation of the micelles.
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Affiliation(s)
- Li-Yan Liu
- College of Science, Civil Aviation University of China, Tianjin 300300, China.
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Gordievskaya YD, Kramarenko EY. Effect of Counterion Size on the Structure of a Flexible Polyelectrolyte Chain in Low-Polar Solvents. POLYMER SCIENCE SERIES C 2018. [DOI: 10.1134/s181123821802008x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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19
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Gordievskaya YD, Budkov YA, Kramarenko EY. An interplay of electrostatic and excluded volume interactions in the conformational behavior of a dipolar chain: theory and computer simulations. SOFT MATTER 2018; 14:3232-3235. [PMID: 29683178 DOI: 10.1039/c8sm00346g] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The effect of an interplay between electrostatic and excluded volume interactions on the conformational behavior of a dipolar chain has been studied theoretically and by means of molecular dynamics simulations. Every monomer unit of the dipolar chain comprises a dipole formed by a charged group of the chain and an oppositely charged counterion. The counterion is assumed to freely move around the chain but keeping the distance between oppositely charged ions (the dipole length) fixed. The novelty of the developed mean-field theory is that variations of the dipole parameters (the dipole length and the counterion size) have been accounted for in both electrostatic and excluded volume contributions to the total free energy of the dipolar chain. It has been shown that conformational transitions between swollen and collapsed states of the chain can be induced by fine-tuning the balance between electrostatic and excluded volume interactions. In particular, in low-polar media not only globule but also extended coil conformations can be realized even under strong electrostatic attraction. The results of MD simulations of a dipolar chain with variable dipolar length support theoretical conclusions.
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Affiliation(s)
- Yu D Gordievskaya
- Faculty of Physics, Lomonosov Moscow State University, Leninskie gory, 1-2, 119991, Moscow, Russia.
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Qian C, Asoh TA, Uyama H. Sea cucumber mimicking bacterial cellulose composite hydrogel with ionic strength-sensitive mechanical adaptivity. Chem Commun (Camb) 2018; 54:11320-11323. [DOI: 10.1039/c8cc05779f] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A novel sea cucumber-mimicking bacterial cellulose composite hydrogel shows stiffness changes in response to ionic strength without significant volume changes.
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Affiliation(s)
- Chen Qian
- Department of Applied Chemistry
- Graduate School of Engineering
- Osaka University
- Suita
- Japan
| | - Taka-Aki Asoh
- Department of Applied Chemistry
- Graduate School of Engineering
- Osaka University
- Suita
- Japan
| | - Hiroshi Uyama
- Department of Applied Chemistry
- Graduate School of Engineering
- Osaka University
- Suita
- Japan
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