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Yellam K, Priyadarshi A, Jha PK. Monte Carlo simulations of spherocylinders interacting with site-dependent square-well potentials. Sci Rep 2024; 14:3753. [PMID: 38355955 PMCID: PMC10866863 DOI: 10.1038/s41598-024-53182-1] [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: 12/12/2023] [Accepted: 01/29/2024] [Indexed: 02/16/2024] Open
Abstract
Monte Carlo simulations are performed to study the self-assembly of a dilute system of spherocylinders interacting with square-well potential. The interactions are defined between randomly placed sites on the axis of the spherocylinder, akin to the interacting groups on a rigid rodlike molecule. This model therefore also serves as a minimal coarse-grained representation of a system of low molecular weight or stiff polymers with contour lengths significantly lower than the persistence length, interacting predominantly with short-range interactions (e.g., hydrogen bonding). The spherocylinder concentration, square-well interaction strength and range, and fraction of interacting sites are varied to study the phase behavior of the system. We observe the formation of dispersed, bundled, and network configurations of the system that may be compared with previous atomistic simulation results of weak polyelectrolytes.
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Affiliation(s)
- Kiranmai Yellam
- Department of Chemical Engineering, IIT Roorkee, Roorkee, Uttarakhand, 247667, India
| | - Anshuman Priyadarshi
- Department of Chemical Engineering, IIT Roorkee, Roorkee, Uttarakhand, 247667, India
| | - Prateek K Jha
- Department of Chemical Engineering, IIT Roorkee, Roorkee, Uttarakhand, 247667, India.
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2
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Wang W, Ma H, Li Y, Yi Z, Li Z, Yan Y. Salt-Induced Coil-Globule Transition of Sulfonate-Modified HPAM is Affected by the Branched Chain Length. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:14969-14976. [PMID: 37812757 DOI: 10.1021/acs.langmuir.3c01832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/11/2023]
Abstract
Polymer flooding is a cheap and efficient method for tertiary oil recovery. However, the failure of partially hydrolyzed polyacrylamide (HPAM) molecules reduces the oil displacement efficiency under high salinity conditions. In this study, we modified HPAM molecules by sulfonic acid groups with different branched chain lengths, and we characterized the structures of these molecules in different salinity solutions through all-atoms molecular dynamics simulation. Compared with the acrylic group, the sulfonate group has excellent salt resistance because of its weak ability to attract cations. When using different lengths of branched linked branch sulfonates, increasing the length of the branched chain can improve the movement ability of sulfonates, so as to play a better salt resistance effect. However, excessive growth of branched chains can cause their association with each other and can lead to polymer folding. Therefore, we believe that the branched chain length of sulfonate should be moderately increased. These results are expected to provide theoretical support for the design and use of salt-resistant polymers..
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Affiliation(s)
- Weiming Wang
- School of Geosciences, China University of Petroleum (East China), Qingdao 266580, China
| | - Haoyu Ma
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Yajing Li
- Department of Fine Chemical, Sinopec, Beijing Research Institute of Chemical Industry, Beijing 100013, China
| | - Zhuo Yi
- Department of Fine Chemical, Sinopec, Beijing Research Institute of Chemical Industry, Beijing 100013, China
| | - Zhen Li
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Youguo Yan
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China
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Pachpinde S, HamsaPriya M, Natarajan U. Molecular dynamics simulations of structure and dynamics in aqueous solution of neutral and ionized derivatives of poly(F): methyl, n-propyl, and isopropyl substitutions. J Mol Model 2022; 28:151. [PMID: 35567722 DOI: 10.1007/s00894-022-05139-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 05/02/2022] [Indexed: 11/26/2022]
Abstract
Chain dimensions, intermolecular structure and hydration of a series of uncharged and cationic poly(vinyl amine) [PVAm] linear polymers having hydrophobic substituent methyl, n-propyl, and isopropyl in the monomer are studied in aqueous solution by molecular dynamics simulations. A conformational transition occurs in the degree of ionization, α, range 0.3 to 0.4. Among the polymers studied, isopropyl substituted PVAm is most hydrophobic and methyl substituted PVAm is the least. The extent of hydrophobicity of the chemical structure is directly correlated to the size of the polymer chain. Conformational dynamics become slower with increase in the degree of charge of the chain and with the size of the substituent side group. The significant hydration of the polymers takes place for 0 ≤ α ≤ 0.5. While the number of H-bonds is not affected significantly by the chemical structure of the chain the relaxation dynamics of polymer-water H-bonds is significantly affected, with the more hydrophobic polymer showing the slowest dynamics. The steric hindrance provided by the hydrophobic substituent groups is responsible for slowing of water orientation dynamics in the vicinity of the polymer. The counter-ion condensation is clearly better and the bound water content is less for the relatively more hydrophobic polymer. The overall behavior of structure and dynamics is in qualitative agreement with that known for other types of polyelectrolytes and solutes in aqueous solution.
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Affiliation(s)
- Sushil Pachpinde
- Macromolecular Modeling and Simulation Lab, Department of Chemical Engineering, Indian Institute of Technology (IIT) Madras, Chennai, 600036, India
| | - M HamsaPriya
- BioSim Lab, Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology (IIT) Madras, Chennai, 600036, India
| | - Upendra Natarajan
- Macromolecular Modeling and Simulation Lab, Department of Chemical Engineering, Indian Institute of Technology (IIT) Madras, Chennai, 600036, India.
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4
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Kapourani A, Andriotis EG, Chachlioutaki K, Kontogiannopoulos KN, Klonos PA, Kyritsis A, Pavlidou E, Bikiaris DN, Fatouros DG, Barmpalexis P. High-Drug-Loading Amorphous Solid Dispersions via In Situ Thermal Cross-Linking: Unraveling the Mechanisms of Stabilization. Mol Pharm 2021; 18:4393-4414. [PMID: 34699238 DOI: 10.1021/acs.molpharmaceut.1c00563] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This article takes a step forward in understanding the mechanisms involved during the preparation and performance of cross-linked high-drug-loading (HDL) amorphous solid dispersions (ASDs). Specifically, ASDs, having 90 wt % poorly water-soluble drug indomethacin (IND), were prepared via in situ thermal cross-linking of poly(acrylic acid) (PAA) and poly(vinyl alcohol) (PVA) and thoroughly evaluated in terms of physical stability and in vitro supersaturation. Results showed that HDL ASDs having excellent active pharmaceutical ingredient (API) amorphous stability and prolonged in vitro supersaturation were prepared by fine tuning the cross-linking procedure. Unraveling of the processes involved during ASD's formation shed light on the significant role of the cross-linking conditions (i.e., temperature and time), the physicochemical properties of the API, and the hydrolysis level of the cross-linker as key factors in modulating ASD's stability. In-depth analysis of the prepared systems revealed the (1) reduction of API's molecular motions within the cross-linked polymeric networks (through API's strong spatial confinement), (2) the structural changes in the prepared cross-linked matrices (induced by the high API drug loading), and (3) the tuning of the cross-linking density via utilization of low-hydrolyzed PVA as the major mechanisms responsible for ASD's exceptional performance. Complementary analysis by means of molecular dynamics simulations also highlighted the vital role of strong drug-polymer intermolecular interactions evolving among the ASD components. Overall, the impression of the complexity of in situ cross-linked ASDs has been reinforced with the excessive variation of parameters investigated in the current study, offering thus insights up to the submolecular level to lay the groundwork and foundations for the comprehensive assessment of a new emerging class of HDL amorphous API formulations.
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Affiliation(s)
- Afroditi Kapourani
- Department of Pharmaceutical Technology, School of Pharmacy, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Eleftherios G Andriotis
- Department of Pharmaceutical Technology, School of Pharmacy, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Konstantina Chachlioutaki
- Department of Pharmaceutical Technology, School of Pharmacy, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Konstantinos N Kontogiannopoulos
- Department of Pharmaceutical Technology, School of Pharmacy, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece.,Natural Products Research Centre of Excellence-AUTH (NatPro-AUTH), Center for Interdisciplinary Research and Innovation (CIRI-AUTH), Thessaloniki 57001, Greece
| | - Panagiotis A Klonos
- Department of Physics, National Technical University of Athens, Zografou Campus, Athens 15780, Greece
| | - Apostolos Kyritsis
- Department of Physics, National Technical University of Athens, Zografou Campus, Athens 15780, Greece
| | - Eleni Pavlidou
- Solid State Section, Physics Department, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Dimitrios N Bikiaris
- Department of Chemistry, Laboratory of Polymer Chemistry and Technology, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Dimitrios G Fatouros
- Department of Pharmaceutical Technology, School of Pharmacy, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Panagiotis Barmpalexis
- Department of Pharmaceutical Technology, School of Pharmacy, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece.,Natural Products Research Centre of Excellence-AUTH (NatPro-AUTH), Center for Interdisciplinary Research and Innovation (CIRI-AUTH), Thessaloniki 57001, Greece
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Molecular Dynamics Study of the Conformation, Ion Adsorption, Diffusion, and Water Structure of Soluble Polymers in Saline Solutions. Polymers (Basel) 2021; 13:polym13203550. [PMID: 34685308 PMCID: PMC8539329 DOI: 10.3390/polym13203550] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/30/2021] [Accepted: 10/05/2021] [Indexed: 11/16/2022] Open
Abstract
Polymers have interesting physicochemical characteristics such as charge density, functionalities, and molecular weight. Such attributes are of great importance for use in industrial purposes. Understanding how these characteristics are affected is still complex, but with the help of molecular dynamics (MD) and quantum calculations (QM), it is possible to understand the behavior of polymers at the molecular level with great consistency. This study was applied to polymers derived from polyacrylamide (PAM) due to its great use in various industries. The polymers studied include hydrolyzed polyacrylamide (HPAM), poly (2-acrylamido-2-methylpropanesulfonate) (PAMPS), polyacrylic acid (PAA), polyethylene oxide polymer (PEO), and guar gum polysaccharide (GUAR). Each one has different attributes, which help in understanding the effects on the polymer and the medium in which it is applied along a broad spectrum. The results include the conformation, diffusion, ion condensation, the structure of the water around the polymer, and interatomic polymer interactions. Such characteristics are important to selecting a polymer depending on the environment in which it is found and its purpose. The effect caused by salinity is particular to each polymer, where polymers with an explicit charge or polyelectrolytes are more susceptible to changes due to salinity, increasing their coiling and reducing their mobility in solution. This naturally reduces its ability to form polymeric bridges due to having a polymer with a smaller gyration radius. In contrast, neutral polymers are less affected in their structure, making them favorable in media with high ionic charges.
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Pachpinde S, Natarajan U. Conformations, inter-molecular structure and hydrogen bond dynamics of neutral and cationic poly(vinyl amine) in aqueous solution. MOLECULAR SIMULATION 2021. [DOI: 10.1080/08927022.2021.1968389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Sushil Pachpinde
- Macromolecular Modeling and Simulation Lab, Department of Chemical Engineering, Indian Institute of Technology (IIT) Madras, Chennai, India
| | - Upendra Natarajan
- Macromolecular Modeling and Simulation Lab, Department of Chemical Engineering, Indian Institute of Technology (IIT) Madras, Chennai, India
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Luo D, Zhen W, Dong C, Zhao L. Performance and multi-scale investigation on the phase miscibility of poly(lactic acid)/amided silica nanocomposites. Int J Biol Macromol 2021; 177:271-283. [PMID: 33621566 DOI: 10.1016/j.ijbiomac.2021.02.117] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 01/14/2021] [Accepted: 02/15/2021] [Indexed: 11/18/2022]
Abstract
In this work, amino-functionalized nano-SiO2 (m@g-SiO2) was synthesized through coupling reaction on the surface of nano-SiO2. Moreover, the optimum preparation conditions of m@g-SiO2 were selected via orthogonal experiments as follows: reaction temperature of 80 °C, reaction time of 8 h, the mass ratio of stearic acid, N,N'‑carbonyldiimidazole, imidazole hydrochloride and g-SiO2 of 0.5:0.7:0.7:1. Fourier transform infrared spectroscopy, static angle measurement and X-ray photoelectron spectroscopy unanimously confirmed the formation of m@g-SiO2. Furthermore, poly(lactic acid)(PLA)/m@g-SiO2 nanocomposites was prepared with m@g-SiO2 as fillers to improve the comprehensive performance of PLA. Then, the mechanical properties and crystallization behavior of PLA/m@g-SiO2 nanocomposites were studied, which showed that the impact strength and elongation-at-break of PLA/m@g-SiO2 (0.3 wt%) nanocomposites were increased by 78.05% and 1148%, respectively, and its crystallinity was increased by 26.46%. Simultaneously, thermal gravimetric analysis indicated that the thermal stability of PLA/m@g-SiO2 nanocomposites was improved. Eventually, the multi-scale investigation on the phase miscibility of PLA/m@g-SiO2 nanocomposites was probed by rheological behaviors analysis and the molecular dynamics simulations, which confirmed that surface modification of SiO2 greatly enhanced the interaction energy and miscibility between the filler and PLA bulk.
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Affiliation(s)
- Dawei Luo
- Key Laboratory of Oil and Gas Fine Chemicals, Ministry of Education and Xinjiang Uygur Autonomous Region, School of Chemical Engineering and Technology, Xinjiang University, Urumqi 830046, China
| | - Weijun Zhen
- Key Laboratory of Oil and Gas Fine Chemicals, Ministry of Education and Xinjiang Uygur Autonomous Region, School of Chemical Engineering and Technology, Xinjiang University, Urumqi 830046, China.
| | - Chengyuan Dong
- Key Laboratory of Oil and Gas Fine Chemicals, Ministry of Education and Xinjiang Uygur Autonomous Region, School of Chemical Engineering and Technology, Xinjiang University, Urumqi 830046, China
| | - Ling Zhao
- Key Laboratory of Oil and Gas Fine Chemicals, Ministry of Education and Xinjiang Uygur Autonomous Region, School of Chemical Engineering and Technology, Xinjiang University, Urumqi 830046, China; State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
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8
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Senechal V, Saadaoui H, Vargas-Alfredo N, Rodriguez-Hernandez J, Drummond C. Weak polyelectrolyte brushes: re-entrant swelling and self-organization. SOFT MATTER 2020; 16:7727-7738. [PMID: 32735003 DOI: 10.1039/d0sm00810a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We have studied the combined influence of pH and ionic strength on the properties of brushes of a weak polyion, poly(acrylic acid), in conditions of grafting density close to the mushroom-brush crossover. By combining atomic force microscopy AFM and quartz crystal microbalance, we show that at low ionic strengths the conformational change of grafted polyions is non-monotonic with increasing pH due to the counterintuitive variation of the ionization degree. Thus, reentrant swelling of the polymer chains is observed with increasing pH. This effect is more important at low polymer grafting densities, when it is accompanied by in-plane heterogeneous distribution at intermediate pH values. In addition, we observed self-assembly on the polymer brush (formation of holes and islands) at pH values below pKa, due to the short-range attractive interaction between uncharged grafted chains. The sensitivity of the ionization of grafted chains to the physicochemical environment was also studied by measuring the interaction force between a silica tip and polymer brushes by atomic force microscopy. The dependence of the ionization of polyions on the presence of the tip points toward important charge regulation effects, in particular at pH values corresponding to partial ionization of the polyion.
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Affiliation(s)
- Vincent Senechal
- CNRS, Centre de Recherche Paul Pascal (CRPP), UMR 5031, F-33600 Pessac, France. and Université de Bordeaux, Centre de Recherche Paul Pascal, F-33600 Pessac, France
| | - Hassan Saadaoui
- CNRS, Centre de Recherche Paul Pascal (CRPP), UMR 5031, F-33600 Pessac, France. and Université de Bordeaux, Centre de Recherche Paul Pascal, F-33600 Pessac, France
| | - Nelson Vargas-Alfredo
- Instituto de Ciencia y Tecnología de Polímeros, CSIC, Juan de la Cierva 3, 28006, Madrid, Spain
| | | | - Carlos Drummond
- CNRS, Centre de Recherche Paul Pascal (CRPP), UMR 5031, F-33600 Pessac, France. and Université de Bordeaux, Centre de Recherche Paul Pascal, F-33600 Pessac, France
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Hydrophobically Functionalized Poly(Acrylic Acid) Comprising the Ester-Type Labile Spacer: Synthesis and Self-Organization in Water. Polymers (Basel) 2020; 12:polym12051185. [PMID: 32455970 PMCID: PMC7285226 DOI: 10.3390/polym12051185] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 05/14/2020] [Accepted: 05/18/2020] [Indexed: 12/19/2022] Open
Abstract
One of the most important properties of hydrophobically functionalized polyelectrolytes (HF-PEs) and their assemblies is their ability to encapsulate hydrophobic/amphiphilic agents and provide release on demand of the entrapped payload. The aim of the present work was to synthesize and study self-organization behavior in aqueous solution of hydrophobically functionalized poly(acrylic acid) (PAA) comprising the ester-type pH labile moiety with various degrees of hydrophobization and side-chain lengths in the absence and presence of appropriate mono- and polyvalent electrolytes (i.e., NaCl or CaCl2). The synthesis and purification of hydrophobically functionalized PAA were performed under mild conditions in order to avoid chemical degradation of the polymers. The modified polyelectrolytes self-assembly in aqueous systems was monitored using diffusion-ordered nuclear magnetic resonance (DOSY NMR). The performed studies, supported by the all-atoms molecular dynamics simulations, revealed a strong dependence of polyelectrolyte self-assembled state on concentration—specific concentration regions with the coexistence of both smaller and larger aggregates were observed (values of hydrodynamic diameter DH around one nanometer and between two to six nanometers, respectively). Our investigations enabled us to gain crucial information about the self-assembly of the hydrophobically functionalized poly(acrylic acid) and opened the possibility of understanding and predicting its performance under various conditions.
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10
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Molecular dynamics simulations of the conformation and diffusion of partially hydrolyzed polyacrylamide in highly saline solutions. Chem Eng Sci 2020. [DOI: 10.1016/j.ces.2019.115366] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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11
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Slavgorodska M, Kyrychenko A. Structure and Dynamics of Pyrene-Labeled Poly(acrylic acid): Molecular Dynamics Simulation Study. CHEMISTRY & CHEMICAL TECHNOLOGY 2020. [DOI: 10.23939/chcht14.01.076] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Bacle P, Jardat M, Marry V, Mériguet G, Batôt G, Dahirel V. Coarse-Grained Models of Aqueous Solutions of Polyelectrolytes: Significance of Explicit Charges. J Phys Chem B 2019; 124:288-301. [DOI: 10.1021/acs.jpcb.9b09725] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Pauline Bacle
- CNRS, Physico-chimie des électrolytes et nano-systèmes interfaciaux, PHENIX, Sorbonne Université, F-75005 Paris, France
| | - Marie Jardat
- CNRS, Physico-chimie des électrolytes et nano-systèmes interfaciaux, PHENIX, Sorbonne Université, F-75005 Paris, France
| | - Virginie Marry
- CNRS, Physico-chimie des électrolytes et nano-systèmes interfaciaux, PHENIX, Sorbonne Université, F-75005 Paris, France
| | - Guillaume Mériguet
- CNRS, Physico-chimie des électrolytes et nano-systèmes interfaciaux, PHENIX, Sorbonne Université, F-75005 Paris, France
| | - Guillaume Batôt
- IFP Énergies Nouvelles, avenue de Bois Préau, 92852 Rueil-Malmaison Cedex, France
| | - Vincent Dahirel
- CNRS, Physico-chimie des électrolytes et nano-systèmes interfaciaux, PHENIX, Sorbonne Université, F-75005 Paris, France
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13
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Multi-scale investigation on the phase miscibility of polylactic acid/o-carboxymethyl chitosan blends. POLYMER 2019. [DOI: 10.1016/j.polymer.2019.05.030] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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14
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Katiyar RS, Jha PK. Mimicking the Dissolution Mechanisms of pH‐Responsive Drug Release Formulations in Atomistic MD Simulations. ADVANCED THEORY AND SIMULATIONS 2019. [DOI: 10.1002/adts.201900053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Ratna S. Katiyar
- Department of Chemical EngineeringIndian Institute of Technology Roorkee Uttarakhand 247667 India
| | - Prateek K. Jha
- Department of Chemical EngineeringIndian Institute of Technology Roorkee Uttarakhand 247667 India
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15
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Gupta AK, Natarajan U. Structure and dynamics of atactic Na+-poly(acrylic) acid (PAA) polyelectrolyte in aqueous solution in dilute, semi-dilute and concentrated regimes. MOLECULAR SIMULATION 2019. [DOI: 10.1080/08927022.2019.1608987] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Abhishek K. Gupta
- Department of Chemical Engineering, Macromolecular Modeling and Simulation Laboratory, Indian Institute of Technology (IIT) Madras, Chennai, India
| | - Upendra Natarajan
- Department of Chemical Engineering, Macromolecular Modeling and Simulation Laboratory, Indian Institute of Technology (IIT) Madras, Chennai, India
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17
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Kyrychenko A, Blazhynska MM, Slavgorodska MV, Kalugin ON. Stimuli-responsive adsorption of poly(acrylic acid) onto silver nanoparticles: Role of polymer chain length and degree of ionization. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2018.11.130] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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18
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Yao G, Zhao J, Ramisetti SB, Wen D. Atomistic Molecular Dynamic Simulation of Dilute Poly(acrylic acid) Solution: Effects of Simulation Size Sensitivity and Ionic Strength. Ind Eng Chem Res 2018. [DOI: 10.1021/acs.iecr.8b03549] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Guice Yao
- School of Chemical and Process Engineering, University of Leeds, Leeds, LS2 9JT, U.K
| | - Jin Zhao
- School of Chemical and Process Engineering, University of Leeds, Leeds, LS2 9JT, U.K
| | | | - Dongsheng Wen
- School of Chemical and Process Engineering, University of Leeds, Leeds, LS2 9JT, U.K
- School of Aeronautic Science and Engineering, Beihang University, Beijing, 100191, China
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Hofzumahaus C, Hebbeker P, Schneider S. Monte Carlo simulations of weak polyelectrolyte microgels: pH-dependence of conformation and ionization. SOFT MATTER 2018; 14:4087-4100. [PMID: 29569677 DOI: 10.1039/c7sm02528a] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In this study, we investigated the effect of pH on single weak acidic polyelectrolyte microgels under salt-free conditions with (i) varying microgel concentration, (ii) varying content of acidic groups and (iii) different crosslinking densities using Monte Carlo simulations under explicit consideration of the protonation/deprotonation reaction. We assessed both global properties, such as the degree of ionization, the degree of swelling and the counterion distribution, and local properties such as the radial network ionization profile and the ionization along the polymer chains as a function of pH. We found a pronounced suppression of the pH-dependent ionization of the microgels, as compared to the ideal titration behavior and a shift of the titration curve to a higher pH originating in the proximity of acidic groups in the microgel. In contrast to macroscopic gels, counterions can leave the microgel, resulting in an effective charge of the network, which hinders the ionization. A decreasing microgel concentration leads to an increased effective charge of the microgel and a more pronounced shift of the titration curve. The number of acidic groups showed only a weak effect on the ionization behavior of the microgels. For two different microgels with different crosslinking densities, similar scaling of the gel size was observed. A distinct transition from an uncharged and unswollen to a highly charged and expanded polymer network was observed for all investigated microgels. The degree of swelling mainly depends on the degree of ionization. An inhomogeneous distribution of the degree of ionization along the radial profile of the microgel was found.
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Affiliation(s)
- C Hofzumahaus
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52056 Aachen, Germany.
| | - P Hebbeker
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52056 Aachen, Germany.
| | - S Schneider
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, D-52056 Aachen, Germany.
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Katiyar RS, Jha PK. Molecular Insights into the Effects of Media–Drug and Carrier–Drug Interactions on pH-Responsive Drug Carriers. Mol Pharm 2018; 15:2479-2483. [DOI: 10.1021/acs.molpharmaceut.8b00151] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Ratna S. Katiyar
- Department of Chemical Engineering, IIT Roorkee, Roorkee, Uttarakhand, India 247667
| | - Prateek K. Jha
- Department of Chemical Engineering, IIT Roorkee, Roorkee, Uttarakhand, India 247667
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