1
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Ruiz-Franco J, Rivas-Barbosa R, Lara-Peña MA, Villanueva-Valencia JR, Licea-Claverie A, Zaccarelli E, Laurati M. Concentration and temperature dependent interactions and state diagram of dispersions of copolymer microgels. SOFT MATTER 2023; 19:3614-3628. [PMID: 37161724 DOI: 10.1039/d3sm00120b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We investigate by means of small angle neutron scattering experiments and numerical simulations the interactions and inter-particle arrangements of concentrated dispersions of copolymer poly(N-isopropylacrylamide)-poly(ethylene glycol methyl ether methacrylate) (PNIPAM-PEGMA) microgels across the volume phase transition (VPT). The scattering data of moderately concentrated dispersions are accurately modeled at all temperatures by using a star polymer form factor and static structure factors calculated from the effective potential obtained from simulations. Interestingly, for temperatures below the VPT temperature (VPTT), the radius of gyration and blob size of the particles significantly decrease with increasing the effective packing fraction in the non-overlapping regime. This is attributed to the presence of charges in the system associated with the use of an ionic initiator in the synthesis. Simulations using the experimentally corroborated interaction potential are used to explore the state diagram in a wide range of effective packing fractions. Below and slightly above the VPTT, the system undergoes an arrest transition mainly driven by the soft repulsion between the particles. Only well above the VPTT the system is found to phase separate before arresting. Our results highlight the versatility and potential of copolymer PNIPAM-PEGMA microgels to explore different kinds of arrested states balancing attraction and repulsion by changing temperature and packing fraction.
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Affiliation(s)
- José Ruiz-Franco
- CNR Institute of Complex Systems, Uos Sapienza, Piazzale Aldo Moro 2, 00185, Roma, Italy.
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, 00185 Roma, Italy
- Physical Chemistry and Soft Matter, Wageningen University & Research, Stippeneng 4, 6708WE Wageningen, The Netherlands
| | - Rodrigo Rivas-Barbosa
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, 00185 Roma, Italy
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Lomas del Bosque 103, 37150 León, Mexico
| | - Mayra A Lara-Peña
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Lomas del Bosque 103, 37150 León, Mexico
- Dipartimento di Chimica and CSGI, Università di Firenze, 50019 Sesto Fiorentino, Italy.
| | | | - Angel Licea-Claverie
- Centro de Graduados e Investigación en Química del Tecnológico Nacional de México/Instituto Tecnológico de Tijuana, 22500 Tijuana, Mexico
| | - Emanuela Zaccarelli
- CNR Institute of Complex Systems, Uos Sapienza, Piazzale Aldo Moro 2, 00185, Roma, Italy.
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, 00185 Roma, Italy
| | - Marco Laurati
- Dipartimento di Chimica and CSGI, Università di Firenze, 50019 Sesto Fiorentino, Italy.
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2
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Huysecom AS, Thielemans W, Moldenaers P, Cardinaels R. A Generalized Mechano-statistical Transient Network Model for Unravelling the Network Topology and Elasticity of Hydrophobically Associating Multiblock Copolymers in Aqueous Solutions. Macromolecules 2023. [DOI: 10.1021/acs.macromol.2c01500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- An-Sofie Huysecom
- Soft Matter, Rheology and Technology, Department of Chemical Engineering, KU Leuven, Celestijnenlaan 200J, 3001Leuven, Belgium
| | - Wim Thielemans
- Sustainable Materials Lab, Department of Chemical Engineering, KU Leuven, campus Kulak Kortrijk, Etienne Sabbelaan 53, 8500Kortrijk, Belgium
| | - Paula Moldenaers
- Soft Matter, Rheology and Technology, Department of Chemical Engineering, KU Leuven, Celestijnenlaan 200J, 3001Leuven, Belgium
| | - Ruth Cardinaels
- Soft Matter, Rheology and Technology, Department of Chemical Engineering, KU Leuven, Celestijnenlaan 200J, 3001Leuven, Belgium
- Processing and Performance of Materials, Department of Mechanical Engineering, TU Eindhoven, Box 513, 5600 MB Eindhoven, The Netherlands
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3
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Peroukidis SD, Stott IP, Mavrantzas VG. Coarse-Grained Model Incorporating Short- and Long-Range Effective Potentials for the Fast Simulation of Micelle Formation in Solutions of Ionic Surfactants. J Phys Chem B 2022; 126:5555-5569. [PMID: 35838193 DOI: 10.1021/acs.jpcb.2c02751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A coarse-grained model comprising short- and long-range effective potentials, parametrized with the iterative Boltzmann inversion (IBI) method, is presented for capturing micelle formation in aqueous solutions of ionic surfactants using as a model system sodium dodecyl sulfate (SDS). In the coarse-grained (CG) model, each SDS molecule is represented as a sequence of four beads while each water molecule is modeled as a single bead. The proposed CG scheme involves ten potential energy functions: four of them describe bonded interactions and control the distribution functions of intramolecular degrees of freedom (bond lengths, valence angles, and dihedrals) along an SDS molecule while the other six account for intermolecular interactions between pairs of SDS and water beads and control the radial distribution functions. The nonbonded effective potentials between coarse-grained SDS molecules extend up to about 12 nm and capture structural and morphological features of the micellar solution both at short and long distances. The long-range component of these potentials, in particular, captures correlations between surfactant molecules belonging to different micelles and is essential to describe ordering associated with micelle formation. A new strategy is introduced for determining the effective potentials through IBI by using information (target distribution functions) extracted from independent atomistic simulations of a micellar reference system (a salt-free SDS solution at total surfactant concentration cT equal to 103 mM, temperature T equal to 300 K, and pressure P equal to 1 atm) obtained through a multiscale approach described in an earlier study. It employs several optimization steps for bonded and nonbonded interactions and a gradual parametrization of the short- and long-range components of the latter, followed by reparametrization of the bonded ones. The proposed CG model can reproduce remarkably accurately the microstructure and morphology of the reference system within only a few hours of computational time. It is therefore very promising for future studies of structural and morphological behavior of various liquid surfactant formulations.
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Affiliation(s)
- Stavros D Peroukidis
- Department of Chemical Engineering, University of Patras and FORTH-ICE/HT, GR 26504, Patras, Greece
| | - Ian P Stott
- Unilever Research and Development Port Sunlight, Bebington CH63 3JW, United Kingdom
| | - Vlasis G Mavrantzas
- Department of Chemical Engineering, University of Patras and FORTH-ICE/HT, GR 26504, Patras, Greece.,Particle Technology Laboratory, Department of Mechanical and Process Engineering, ETH Zürich, CH-8092 Zürich, Switzerland
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4
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Rivas-Barbosa R, Ruiz-Franco J, Lara-Peña MA, Cardellini J, Licea-Claverie A, Camerin F, Zaccarelli E, Laurati M. Link between Morphology, Structure, and Interactions of Composite Microgels. Macromolecules 2022; 55:1834-1843. [PMID: 35283539 PMCID: PMC8908736 DOI: 10.1021/acs.macromol.1c02171] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 01/19/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Rodrigo Rivas-Barbosa
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, 00185 Roma, Italy
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Lomas del Bosque 103, 37150 León, Mexico
| | - José Ruiz-Franco
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, 00185 Roma, Italy
- CNR Institute of Complex Systems, Uos Sapienza, Piazzale Aldo Moro 2, 00185 Roma, Italy
- Physical Chemistry and Soft Matter, Wageningen University & Research, Stippeneng 4, 6708WE Wageningen, The Netherlands
| | - Mayra A. Lara-Peña
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Lomas del Bosque 103, 37150 León, Mexico
| | - Jacopo Cardellini
- Dipartimento di Chimica and CSGI, Universitá di Firenze, 50019 Sesto Fiorentino, Italy
| | - Angel Licea-Claverie
- Centro de Graduados e Investigación en Química del Tecnológico Nacional de México, Instituto Tecnológico de Tijuana, 22500 Tijuana, Mexico
| | - Fabrizio Camerin
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, 00185 Roma, Italy
- CNR Institute of Complex Systems, Uos Sapienza, Piazzale Aldo Moro 2, 00185 Roma, Italy
| | - Emanuela Zaccarelli
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, 00185 Roma, Italy
- CNR Institute of Complex Systems, Uos Sapienza, Piazzale Aldo Moro 2, 00185 Roma, Italy
| | - Marco Laurati
- Dipartimento di Chimica and CSGI, Universitá di Firenze, 50019 Sesto Fiorentino, Italy
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5
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Rogers BA, Okur HI, Yan C, Yang T, Heyda J, Cremer PS. Weakly hydrated anions bind to polymers but not monomers in aqueous solutions. Nat Chem 2022; 14:40-45. [PMID: 34725491 DOI: 10.1038/s41557-021-00805-z] [Citation(s) in RCA: 51] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 08/31/2021] [Indexed: 02/07/2023]
Abstract
Weakly hydrated anions help to solubilize hydrophobic macromolecules in aqueous solutions, but small molecules comprising the same chemical constituents precipitate out when exposed to these ions. Here, this apparent contradiction is resolved by systematically investigating the interactions of NaSCN with polyethylene oxide oligomers and polymers of varying molecular weight. A combination of spectroscopic and computational results reveals that SCN- accumulates near the surface of polymers, but is excluded from monomers. This occurs because SCN- preferentially binds to the centre of macromolecular chains, where the local water hydrogen-bonding network is disrupted. These findings suggest a link between ion-specific effects and theories addressing how hydrophobic hydration is modulated by the size and shape of a hydrophobic entity.
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Affiliation(s)
- Bradley A Rogers
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Halil I Okur
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA.,Department of Chemistry and National Nanotechnology Research Center (UNAM), Bilkent University, Ankara, Turkey
| | - Chuanyu Yan
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Tinglu Yang
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Jan Heyda
- Department of Physical Chemistry, University of Chemistry and Technology, Prague, Dejvice, Czech Republic
| | - Paul S Cremer
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA. .,Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA.
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6
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Sponseller D, Blaisten-Barojas E. Solutions and Condensed Phases of PEG 2000 from All-Atom Molecular Dynamics. J Phys Chem B 2021; 125:12892-12901. [PMID: 34783248 DOI: 10.1021/acs.jpcb.1c06397] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Extensive all-atom molecular dynamics studies of polyethylene glycol (PEG2000) when solvated and in the polymer bulk condensed phases were performed across a wide temperature range. We proposed two modified all-atom force field and observed the fate of the PEG2000 macromolecule when solvated in water, water with 4% ethanol, and ethyl acetate. In aqueous solutions, the macromolecule collapsed into a prolate spheroidal ball-like structure while adopting a rather elongated coiled structure in ethyl acetate. Inspection of the polymer-condensed phases across the 150-340 K temperature range enabled the atomistic view of the solid glass below the glass transition temperature of 230 K < Tg < 250 K and the rubber behavior above Tg. Predicted properties include the enthalpy, density, and cohesive energy temperature behavior, the specific heat, thermal expansivity, thermal compressibility, bulk modulus, and Hildebrand solubility parameter both below and above Tg. Within the polymer matrix, the PEG2000 macromolecules were entangled displaying a wide distribution of sizes that persisted when transitioning from the glass to the rubbery phases. Calculated properties agree very well with experiments when available or stand as crucial predictions while awaiting experimental measurement. Understanding the thermodynamics and structure of this useful polymer enables the efficient prediction of its behavior when building novel composite materials for nanomedicine and nanotherapeutics.
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Affiliation(s)
- Daniel Sponseller
- Center for Simulation and Modeling, and Department of Computational and Data Sciences, George Mason University, Fairfax, Virginia 22030, United States
| | - Estela Blaisten-Barojas
- Center for Simulation and Modeling, and Department of Computational and Data Sciences, George Mason University, Fairfax, Virginia 22030, United States
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7
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Wang X, Bowman J, Tu S, Nykypanchuk D, Kuksenok O, Minko S. Polyethylene Glycol Crowder's Effect on Enzyme Aggregation, Thermal Stability, and Residual Catalytic Activity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:8474-8485. [PMID: 34236863 DOI: 10.1021/acs.langmuir.1c00872] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Protein stability and performance in various natural and artificial systems incorporating many other macromolecules for therapeutic, diagnostic, sensor, and biotechnological applications attract increasing interest with the expansion of these technologies. Here we address the catalytic activity of lysozyme protein (LYZ) in the presence of a polyethylene glycol (PEG) crowder in a broad range of concentrations and temperatures in aqueous solutions of two different molecular mass PEG samples (Mw = 3350 and 10000 g/mol). The phase behavior of PEG-protein solutions is examined by using dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS), while the enzyme denaturing is monitored by using an activity assay (AS) and circular dichroism (CD) spectroscopy. Molecular dynamic (MD) simulations are used to illustrate the effect of PEG concentration on protein stability at high temperatures. The results demonstrate that LYZ residual activity after 1 h incubation at 80 °C is improved from 15% up to 55% with the addition of PEG. The improvement is attributed to two underlying mechanisms. (i) Primarily, the stabilizing effect is due to the suppression of the enzyme aggregation because of the stronger PEG-protein interactions caused by the increased hydrophobicity of PEG and lysozyme at elevated temperatures. (ii) The MD simulations showed that the addition of PEG to some degree stabilizes the secondary structures of the enzyme by delaying unfolding at elevated temperatures. The more pronounced effect is observed with an increase in PEG concentration. This trend is consistent with CD and AS experimental results, where the thermal stability is strengthened with increasing of PEG concentration and molecular mass. The results show that the highest stabilizing effect is approached at the critical overlap concentration of PEG.
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Affiliation(s)
- Xue Wang
- Nanostructured Materials Lab, University of Georgia, Athens, Georgia 30602, United States
| | - Jeremy Bowman
- Nanostructured Materials Lab, University of Georgia, Athens, Georgia 30602, United States
| | - Sidong Tu
- Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634, United States
| | - Dmytro Nykypanchuk
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Olga Kuksenok
- Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634, United States
| | - Sergiy Minko
- Nanostructured Materials Lab, University of Georgia, Athens, Georgia 30602, United States
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8
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Spoel D, Zhang J, Zhang H. Quantitative predictions from molecular simulations using explicit or implicit interactions. WIRES COMPUTATIONAL MOLECULAR SCIENCE 2021. [DOI: 10.1002/wcms.1560] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- David Spoel
- Uppsala Center for Computational Chemistry, Science for Life Laboratory, Department of Cell and Molecular Biology Uppsala University Uppsala Sweden
| | - Jin Zhang
- Department of Chemistry Southern University of Science and Technology Shenzhen China
| | - Haiyang Zhang
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering University of Science and Technology Beijing Beijing China
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9
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Ziolek RM, Smith P, Pink DL, Dreiss CA, Lorenz CD. Unsupervised Learning Unravels the Structure of Four-Arm and Linear Block Copolymer Micelles. Macromolecules 2021. [DOI: 10.1021/acs.macromol.0c02523] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Robert M. Ziolek
- Biological Physics and Soft Matter Group, Department of Physics, King’s College London, London WC2R 2LS, U.K
| | - Paul Smith
- Biological Physics and Soft Matter Group, Department of Physics, King’s College London, London WC2R 2LS, U.K
| | - Demi L. Pink
- Biological Physics and Soft Matter Group, Department of Physics, King’s College London, London WC2R 2LS, U.K
| | - Cécile A. Dreiss
- Institute of Pharmaceutical Science, King’s College London, London SE1 9NH, U.K
| | - Christian D. Lorenz
- Biological Physics and Soft Matter Group, Department of Physics, King’s College London, London WC2R 2LS, U.K
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10
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Rick SW. Insights into the Thermal Response of a Poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) Triblock Polymer in Water. J Phys Chem B 2021; 125:2167-2173. [PMID: 33606935 DOI: 10.1021/acs.jpcb.0c11279] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A thermal responsive block copolymer made up of ethylene oxide (EO) and propylene oxide (PO) blocks was simulated with optimized atomistic potentials and enhanced sampling methods over a range of temperatures. The results for the L42 pluronic polymer (EO)4(PO)22(EO)4, which is known to undergo a transition in this temperature range, and the similarly sized (EO)30 polymer, which does not, are compared. The thermal responsive L42 polymers in a dilute solution tend to aggregate, and this tendency gets stronger as temperature increases. The poly(ethylene oxide) polymer shows no such tendency. The aggregation is stabilized by the hydrophobic contact of the propylene oxide methyl groups, which outweighs a small loss in hydrogen bonds between the ether oxygens and water.
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Affiliation(s)
- Steven W Rick
- Department of Chemistry, University of New Orleans, New Orleans, Louisiana 70148, United States
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11
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Ottallah T, Parandian SA, Rick SW. Analysis of Atomistic Potentials for Poly(ethylene glycol) Ethers. J Chem Theory Comput 2021; 17:315-321. [PMID: 33258591 DOI: 10.1021/acs.jctc.0c00871] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Two different potentials, the modified TraPPE-UA model of Fischer, J. [ J. Phys. Chem. B 2008, 112, 2388-2398] and the modified general AMBER force-field (GAFF) model of Barbosa, N. S. V. [ J. Mol. Model. 2017, 23, 194]are tested for a variety of temperature-dependent properties for neat and aqueous solutions for small poly(oxyethylene) (PEO) oligomers and larger polymers. A set of charges for PEO of arbitrary size is adapted for the modified GAFF model. Both models accurately reproduce experimental properties, but we find that the modified TraPPE-UA model is more accurate.
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Affiliation(s)
- Tasneem Ottallah
- Department of Chemistry, University of New Orleans, New Orleans, Louisiana 70148, United States
| | - Sophia A Parandian
- Department of Chemistry, University of New Orleans, New Orleans, Louisiana 70148, United States
| | - Steven W Rick
- Department of Chemistry, University of New Orleans, New Orleans, Louisiana 70148, United States
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12
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Ziolek RM, Omar J, Hu W, Porcar L, González-Gaitano G, Dreiss CA, Lorenz CD. Understanding the pH-Directed Self-Assembly of a Four-Arm Block Copolymer. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c01694] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Robert M. Ziolek
- Biological Physics and Soft Matter Group, Department of Physics, King’s College London, London WC2R 2LS, United Kingdom
| | - Jasmin Omar
- Institute of Pharmaceutical Science, King’s College London, London SE1 9NH, United Kingdom
| | - Wenjing Hu
- Institute of Pharmaceutical Science, King’s College London, London SE1 9NH, United Kingdom
| | - Lionel Porcar
- Institut Max Von Laue Paul Langevin, F-38042 Grenoble 9, France
| | | | - Cécile A. Dreiss
- Institute of Pharmaceutical Science, King’s College London, London SE1 9NH, United Kingdom
| | - Christian D. Lorenz
- Biological Physics and Soft Matter Group, Department of Physics, King’s College London, London WC2R 2LS, United Kingdom
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13
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Baul U, Bley M, Dzubiella J. Thermal Compaction of Disordered and Elastin-like Polypeptides: A Temperature-Dependent, Sequence-Specific Coarse-Grained Simulation Model. Biomacromolecules 2020; 21:3523-3538. [DOI: 10.1021/acs.biomac.0c00546] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Upayan Baul
- Applied Theoretical Physics—Computational Physics, Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder Strasse 3, D-79104 Freiburg, Germany
| | - Michael Bley
- Applied Theoretical Physics—Computational Physics, Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder Strasse 3, D-79104 Freiburg, Germany
| | - Joachim Dzubiella
- Applied Theoretical Physics—Computational Physics, Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder Strasse 3, D-79104 Freiburg, Germany
- Cluster of Excellence livMatS@FIT—Freiburg Center for Interactive Materials and Bioinspired Technologies, Albert-Ludwigs-Universität Freiburg, Georges-Köhler-Allee 105, D-79110 Freiburg, Germany
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14
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Griffiths MZ, Shinoda W. tSPICA: Temperature- and Pressure-Dependent Coarse-Grained Force Field for Organic Molecules. J Chem Inf Model 2019; 59:3829-3838. [DOI: 10.1021/acs.jcim.9b00480] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Mark Z. Griffiths
- Department of Materials Chemistry, Nagoya University, Furo-cho Chikusa-ku, Nagoya 464-8603, Japan
| | - Wataru Shinoda
- Department of Materials Chemistry, Nagoya University, Furo-cho Chikusa-ku, Nagoya 464-8603, Japan
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15
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Ensing B, Tiwari A, Tros M, Hunger J, Domingos SR, Pérez C, Smits G, Bonn M, Bonn D, Woutersen S. On the origin of the extremely different solubilities of polyethers in water. Nat Commun 2019; 10:2893. [PMID: 31253797 PMCID: PMC6599002 DOI: 10.1038/s41467-019-10783-z] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 05/21/2019] [Indexed: 11/09/2022] Open
Abstract
The solubilities of polyethers are surprisingly counter-intuitive. The best-known example is the difference between polyethylene glycol ([-CH2-CH2-O-]n) which is infinitely soluble, and polyoxymethylene ([-CH2-O-]n) which is completely insoluble in water, exactly the opposite of what one expects from the C/O ratios of these molecules. Similar anomalies exist for oligomeric and cyclic polyethers. To solve this apparent mystery, we use femtosecond vibrational and GHz dielectric spectroscopy with complementary ab initio calculations and molecular dynamics simulations. We find that the dynamics of water molecules solvating polyethers is fundamentally different depending on their C/O composition. The ab initio calculations and simulations show that this is not because of steric effects (as is commonly believed), but because the partial charge on the O atoms depends on the number of C atoms by which they are separated. Our results thus show that inductive effects can have a major impact on aqueous solubilities.
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Affiliation(s)
- Bernd Ensing
- Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, The Netherlands.
| | - Ambuj Tiwari
- Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, The Netherlands
| | - Martijn Tros
- Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, The Netherlands
| | - Johannes Hunger
- Max Planck Institute for Polymer Research, Department of Molecular spectroscopy, Ackermannweg 10, 55128, Mainz, Germany.
| | - Sérgio R Domingos
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607, Hamburg, Germany
| | - Cristóbal Pérez
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607, Hamburg, Germany
| | - Gertien Smits
- Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, The Netherlands
| | - Mischa Bonn
- Max Planck Institute for Polymer Research, Department of Molecular spectroscopy, Ackermannweg 10, 55128, Mainz, Germany.
| | - Daniel Bonn
- Institute of Physics, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, The Netherlands
| | - Sander Woutersen
- Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, The Netherlands.
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16
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Chudoba R, Heyda J, Dzubiella J. Tuning the collapse transition of weakly charged polymers by ion-specific screening and adsorption. SOFT MATTER 2018; 14:9631-9642. [PMID: 30457144 DOI: 10.1039/c8sm01646a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The experimentally observed swelling and collapse response of weakly charged polymers to the addition of specific salts displays quite convoluted behavior that is not easy to categorize. Here we use a minimalistic implicit-solvent/explicit-salt simulation model with a focus on ion-specific interactions between ions and a single weakly charged polyelectrolyte to qualitatively explain the observed effects. In particular, we demonstrate ion-specific screening and bridging effects cause collapse at low salt concentrations whereas the same strong ion-specific direct interactions drive re-entrant swelling at high concentrations. Consistently with experiments, a distinct salt concentration at which the salting-out power of anions inverts from the reverse to direct Hofmeister series is observed. At this so called isospheric point, the ion-specific effects vanish. Furthermore, with additional simplifying assumptions, an ion-specific mean-field model is developed for the collapse transition which quantitatively agrees with the simulations. Our work demonstrates the sensitivity of the structural behavior of charged polymers to the addition of specific salt beyond simple screening and shall be useful for further guidance of experiments.
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Affiliation(s)
- Richard Chudoba
- Institut für Physik, Humboldt-Universität zu Berlin, Newtonstraße 15, D-12489 Berlin, Germany.
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Bejagam KK, An Y, Singh S, Deshmukh SA. Machine-Learning Enabled New Insights into the Coil-to-Globule Transition of Thermosensitive Polymers Using a Coarse-Grained Model. J Phys Chem Lett 2018; 9:6480-6488. [PMID: 30372083 DOI: 10.1021/acs.jpclett.8b02956] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We present a computational framework that integrates coarse-grained (CG) molecular dynamics (MD) simulations and a data-driven machine-learning (ML) method to gain insights into the conformations of polymers in solutions. We employ this framework to study conformational transition of a model thermosensitive polymer, poly( N-isopropylacrylamide) (PNIPAM). Here, we have developed the first of its kind, a temperature-independent CG model of PNIPAM that can accurately predict its experimental lower critical solution temperature (LCST) while retaining the tacticity in the presence of an explicit water model. The CG model was extensively validated by performing CG MD simulations with different initial conformations, varying the radius of gyration of chain, the chain length, and the angle between the adjacent monomers of the initial configuration of PNIPAM (total simulation time = 90 μs). Moreover, for the first time, we utilize the nonmetric multidimensional scaling (NMDS) method, a data-driven ML approach, to gain further insights into the mechanisms and pathways of this coil-to-globule transition by analyzing CG MD simulation trajectories. NMDS analysis provides entirely new insights and shows multiple metastable states of PNIPAM during its coil-to-globule transition above the LCST.
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Affiliation(s)
- Karteek K Bejagam
- Department of Chemical Engineering , Virginia Tech , Blacksburg , Virginia 24061 , United States
| | - Yaxin An
- Department of Chemical Engineering , Virginia Tech , Blacksburg , Virginia 24061 , United States
| | - Samrendra Singh
- CNH Industrial , Burr Ridge , Illinois 60527 , United States
| | - Sanket A Deshmukh
- Department of Chemical Engineering , Virginia Tech , Blacksburg , Virginia 24061 , United States
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Coarse-Grained Simulations of Aqueous Thermoresponsive Polyethers. Polymers (Basel) 2018; 10:polym10050475. [PMID: 30966509 PMCID: PMC6415429 DOI: 10.3390/polym10050475] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 04/11/2018] [Accepted: 04/12/2018] [Indexed: 11/28/2022] Open
Abstract
Thermoresponsive polymers can change structure or solubility as a function of temperature. Block co-polymers of polyethers have a response that depends on polymer molecular weight and co-polymer composition. A coarse-grained model for aqueous polyethers is developed and applied to polyethylene oxide and polyethylene oxide-polypropylene oxide-polyethylene oxide triblock co-polymers. In this model, no interaction sites on hydrogen atoms are included, no Coulombic interactions are present, and all interactions are short-ranged, treated with a combination of two- and three-body terms. Our simulations find that The triblock co-polymers tend to associate at temperatures above 350 K. The aggregation is stabilized by contact between The hydrophobic methyl groups on The propylene oxide monomers and involves a large, favorable change in entropy.
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