1
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Zorn R, Szymoniak P, Kolmangadi MA, Malpass-Evans R, McKeown NB, Jalarvo NH, Tyagi M, Böhning M, Schönhals A. Microscopic molecular mobility of high-performance polymers of intrinsic microporosity revealed by neutron scattering - bend fluctuations and signature of methyl group rotation. SOFT MATTER 2024; 20:5153-5163. [PMID: 38895763 DOI: 10.1039/d4sm00520a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Polymers of intrinsic microporosity exhibit a combination of high gas permeability and reasonable permselectivity, which makes them attractive candidates for gas separation membrane materials. The diffusional selective gas transport properties are connected to the molecular mobility of these polymers in the condensed state. Incoherent quasielastic neutron scattering was carried out on two polymers of intrinsic microporosity, PIM-EA-TB(CH3) and its demethylated counterpart PIM-EA-TB(H2), which have high Brunauer-Emmett-Teller surface area values of 1030 m2 g-1 and 836 m2 g-1, respectively. As these two polymers only differ in the presence of two methyl groups at the ethanoanthracene unit, the effect of methyl group rotation can be investigated solely. To cover a broad dynamic range, neutron time-of-flight was combined with neutron backscattering. The demethylated PIM-EA-TB(H2) exhibits a relaxation process with a weak intensity at short times. As the backbone is rigid and stiff this process was assigned to bend-and-flex fluctuations. This process was also observed for the PIM-EA-TB(CH3). A further relaxation process is found for PIM-EA-TB(CH3), which is the methyl group rotation. It was analyzed by a jump-diffusion in a three-fold potential considering also the fact that only a fraction of the present hydrogens in PIM-EA-TB(CH3) participate in the methyl group rotation. This analysis can quantitatively describe the q dependence of the elastic incoherent structure factor. Furthermore, a relaxation time for the methyl group rotation can be extracted. A high activation energy of 35 kJ mol-1 was deduced. This high activation energy evidences a strong hindrance of the methyl group rotation in the bridged PIM-EA-TB(CH3) structure.
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Affiliation(s)
- Reiner Zorn
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1) and Institute for Biological Information Processing (IBI-8), Jülich 52425, Germany
| | - Paulina Szymoniak
- Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, Berlin 12205, Germany.
| | - Mohamed A Kolmangadi
- Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, Berlin 12205, Germany.
| | - Richard Malpass-Evans
- EastChem, School of Chemistry, David Brewster Road, University of Edinburgh, Edinburgh, EH9 3FJ, UK
| | - Neil B McKeown
- EastChem, School of Chemistry, David Brewster Road, University of Edinburgh, Edinburgh, EH9 3FJ, UK
| | - Niina H Jalarvo
- Neutron Scattering Division, OAK RIDGE National Laboratory, One Bethel Valley Rd, Oak Ridge, TN 37831, USA
| | - Madhusudan Tyagi
- NIST Center for Neutron Research Gaithersburg MD 20899 and Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742, USA
| | - Martin Böhning
- Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, Berlin 12205, Germany.
| | - Andreas Schönhals
- Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, Berlin 12205, Germany.
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, Berlin 10623, Germany
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2
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Kolmangadi MA, Szymoniak P, Zorn R, Böhning M, Wolf M, Zamponi M, Schönhals A. Molecular mobility in high‐performance polynorbornenes: A combined broadband dielectric, advanced calorimetry, and neutron scattering investigation*. POLYM ENG SCI 2022. [DOI: 10.1002/pen.25995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
| | - Paulina Szymoniak
- Bundesanstalt für Materialforschung und ‐prüfung (BAM) Berlin Germany
| | - Reiner Zorn
- Forschungszentrum Jülich GmbH Jülich Centre for Neutron Science (JCNS‐1) and Institute for Biological Information Processing (IBI‐8) Jülich Germany
| | - Martin Böhning
- Bundesanstalt für Materialforschung und ‐prüfung (BAM) Berlin Germany
| | - Marcell Wolf
- Heinz Maier‐Leibnitz Zentrum (MLZ) Technische Universität München Garching Germany
| | - Michaela Zamponi
- Forschungszentrum Jülich GmbH Jülich Centre for Neutron Science at MLZ Garching Germany
| | - Andreas Schönhals
- Bundesanstalt für Materialforschung und ‐prüfung (BAM) Berlin Germany
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3
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Berlie A, Terry I, Szablewski M, Telling M, Apperley D, Hodgkinson P, Zeller D. A study of the dynamics and structure of the dielectric anomaly within the molecular solid TEA(TCNQ) 2. Phys Chem Chem Phys 2022; 24:7481-7492. [PMID: 35274651 DOI: 10.1039/d2cp00142j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
With rising interest in organic-based functional materials, it is important to understand the nature of magnetic and electrical transitions within these types of systems. One intriguing material is triethylammonium bis-7,7,8,8-tetracyanoquinodimethane (TEA(TCNQ)2) where there is an order-disorder transition at ∼220 K. This work focuses on novel neutron scattering techniques to understand the motion of the TEA cations at this transition and explain why we see the dielectric behaviour and possible ferroelectricity within this type of system. We show that the motion of the methyl groups of the TEA cation is spatially restricted below 220 K, whereas above the dielectric anomaly at 220 K, they are free to re-orientate, which ultimately leads to some rich behaviour that could be further exploited. Lastly, we also study the dynamics at this transition using a variety of additional techniques, helping to provide a consistent picture of the motions of the cations.
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Affiliation(s)
- Adam Berlie
- ISIS Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Chilton, Oxfordshire, OX11 0QX, UK.
| | - Ian Terry
- Department of Physics, Durham University, South Road, Durham, DH1 3LE, UK
| | - Marek Szablewski
- Department of Physics, Durham University, South Road, Durham, DH1 3LE, UK
| | - Mark Telling
- ISIS Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Chilton, Oxfordshire, OX11 0QX, UK.
| | - David Apperley
- Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, UK
| | - Paul Hodgkinson
- Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, UK
| | - Dominik Zeller
- Institut Laue Langevin, BP 156, 38042 Grenoble Cedex 9, France
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4
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Schönhals A, Szymoniak P, Kolmangadi MA, Böhning M, Zamponi M, Frick B, Appel M, Günther G, Russina M, Alentiev DA, Bermeshev M, Zorn R. Microscopic dynamics of highly permeable super glassy polynorbornenes revealed by quasielastic neutron scattering. J Memb Sci 2022. [DOI: 10.1016/j.memsci.2021.119972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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5
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Zorn R. Resolution-intensity optimisation on quasielastic neutron scattering spectrometers. JOURNAL OF NEUTRON RESEARCH 2021. [DOI: 10.3233/jnr-210029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In quasieleastic neutron scattering spectrometers one usually faces a trade-off between energy resolution and counting statistics. If the resolution is improved the intensity at the detectors reduces and vice versa. It is not immediately clear how to weigh both factors against each other. In this paper it is proposed to use the maximum time obtainable by Fourier transform of the spectra as the quantity to be optimised. It is shown that this leads to a well-defined criterion for the choice of the resolution.
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Affiliation(s)
- Reiner Zorn
- Jülich Centre for Neutron Science (JCNS-1) and Institute for Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, Germany. E-mail:
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6
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Drużbicki K, Gaboardi M, Fernandez-Alonso F. Dynamics & Spectroscopy with Neutrons-Recent Developments & Emerging Opportunities. Polymers (Basel) 2021; 13:1440. [PMID: 33947108 PMCID: PMC8125526 DOI: 10.3390/polym13091440] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 04/27/2021] [Indexed: 12/19/2022] Open
Abstract
This work provides an up-to-date overview of recent developments in neutron spectroscopic techniques and associated computational tools to interrogate the structural properties and dynamical behavior of complex and disordered materials, with a focus on those of a soft and polymeric nature. These have and continue to pave the way for new scientific opportunities simply thought unthinkable not so long ago, and have particularly benefited from advances in high-resolution, broadband techniques spanning energy transfers from the meV to the eV. Topical areas include the identification and robust assignment of low-energy modes underpinning functionality in soft solids and supramolecular frameworks, or the quantification in the laboratory of hitherto unexplored nuclear quantum effects dictating thermodynamic properties. In addition to novel classes of materials, we also discuss recent discoveries around water and its phase diagram, which continue to surprise us. All throughout, emphasis is placed on linking these ongoing and exciting experimental and computational developments to specific scientific questions in the context of the discovery of new materials for sustainable technologies.
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Affiliation(s)
- Kacper Drużbicki
- Materials Physics Center, CSIC-UPV/EHU, Paseo Manuel de Lardizabal 5, 20018 Donostia-San Sebastian, Spain;
- Polish Academy of Sciences, Center of Molecular and Macromolecular Studies, Sienkiewicza 112, 90-363 Lodz, Poland
| | - Mattia Gaboardi
- Elettra—Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in Area Science Park, 34149 Trieste, Italy;
| | - Felix Fernandez-Alonso
- Materials Physics Center, CSIC-UPV/EHU, Paseo Manuel de Lardizabal 5, 20018 Donostia-San Sebastian, Spain;
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebastian, Spain
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK
- IKERBASQUE, Basque Foundation for Science, Plaza Euskadi 5, 48009 Bilbao, Spain
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Khairy Y, Alvarez F, Arbe A, Colmenero J. Disentangling Self-Atomic Motions in Polyisobutylene by Molecular Dynamics Simulations. Polymers (Basel) 2021; 13:polym13040670. [PMID: 33672368 PMCID: PMC7927061 DOI: 10.3390/polym13040670] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/08/2021] [Accepted: 02/17/2021] [Indexed: 01/16/2023] Open
Abstract
We present fully atomistic molecular dynamics simulations on polyisobutylene (PIB) in a wide temperature range above the glass transition. The cell is validated by direct comparison of magnitudes computed from the simulation and measured by neutron scattering on protonated samples reported in previous works. Once the reliability of the simulation is assured, we exploit the information in the atomic trajectories to characterize the dynamics of the different kinds of atoms in PIB. All of them, including main-chain carbons, show a crossover from Gaussian to non-Gaussian behavior in the intermediate scattering function that can be described in terms of the anomalous jump diffusion model. The full characterization of the methyl-group hydrogen motions requires accounting for rotational motions. We show that the usually assumed statistically independence of rotational and segmental motions fails in this case. We apply the rotational rate distribution model to correlation functions calculated for the relative positions of methyl-group hydrogens with respect to the carbon atom at which they are linked. The contributions to the vibrational density of states are also discussed. We conclude that methyl-group rotations are coupled with the main-chain dynamics. Finally, we revise in the light of the simulations the hypothesis and conclusions made in previously reported neutron scattering investigations on protonated samples trying to address the origin of the dielectric β-process.
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Affiliation(s)
- Yasmin Khairy
- Physics Department, Faculty of Science, Zagazig University, Zagazig 44519, Egypt;
- Centro de Física de Materiales (CSIC, UPV/EHU), Paseo Manuel de Lardizabal 5, E-20018 San Sebastián, Spain; (F.A.); (A.A.)
| | - Fernando Alvarez
- Centro de Física de Materiales (CSIC, UPV/EHU), Paseo Manuel de Lardizabal 5, E-20018 San Sebastián, Spain; (F.A.); (A.A.)
- Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, E-20018 San Sebastián, Spain
- Departamento de Polímeros y Materiales Avanzados: Física, Química y Tecnología (UPV/EHU), Apartado 1072, E-20080 San Sebastián, Spain
| | - Arantxa Arbe
- Centro de Física de Materiales (CSIC, UPV/EHU), Paseo Manuel de Lardizabal 5, E-20018 San Sebastián, Spain; (F.A.); (A.A.)
- Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, E-20018 San Sebastián, Spain
| | - Juan Colmenero
- Centro de Física de Materiales (CSIC, UPV/EHU), Paseo Manuel de Lardizabal 5, E-20018 San Sebastián, Spain; (F.A.); (A.A.)
- Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, E-20018 San Sebastián, Spain
- Departamento de Polímeros y Materiales Avanzados: Física, Química y Tecnología (UPV/EHU), Apartado 1072, E-20080 San Sebastián, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, E-20018 San Sebastián, Spain
- Correspondence:
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8
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Švajdlenková H, Šauša O, Adichtchev SV, Surovtsev NV, Novikov VN, Bartoš J. On the Mutual Relationships between Molecular Probe Mobility and Free Volume and Polymer Dynamics in Organic Glass Formers: cis-1,4-poly(isoprene). Polymers (Basel) 2021; 13:polym13020294. [PMID: 33477605 PMCID: PMC7831304 DOI: 10.3390/polym13020294] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/08/2021] [Accepted: 01/11/2021] [Indexed: 11/16/2022] Open
Abstract
We report on the reorientation dynamics of small spin probe 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO) in cis-1,4-poly(isoprene) (cis-1,4-PIP10k) from electron spin resonance (ESR) and the free volume of cis-1,4-PIP10k from positron annihilation lifetime spectroscopy (PALS) in relation to the high-frequency relaxations of cis-1,4-PIP10k using light scattering (LS) as well as to the slow and fast processes from broadband dielectric spectroscopy (BDS) and neutron scattering (NS). The hyperfine coupling constant, 2Azz
'(T), and the correlation times, τ
c(T), of cis-1,4-PIP10k/TEMPO system as a function of temperature exhibit several regions of the distinct spin probe TEMPO dynamics over a wide temperature range from 100 K up to 350 K. The characteristic ESR temperatures of changes in the spin probe dynamics in cis-1,4-PIP10k/TEMPO system are closely related to the characteristic PALS ones reflecting changes in the free volume expansion from PALS measurement. Finally, the time scales of the slow and fast dynamics of TEMPO in cis-1,4-PIP10k are compared with all of the six known slow and fast relaxation modes from BDS, LS and NS techniques with the aim to discuss the controlling factors of the spin probe reorientation mobility in polymer, oligomer and small molecular organic glass-formers.
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Affiliation(s)
- Helena Švajdlenková
- Polymer Institute of SAS, Dúbravská Cesta 9, 84541 Bratislava, Slovakia;
- Correspondence:
| | - Ondrej Šauša
- Institute of Physics of SAS, Dúbravská Cesta 9, 84511 Bratislava, Slovakia;
- Department of Nuclear Chemistry, Faculty of Natural Sciences, Comenius University, Mlynska Dolina, Ilkovicova 6, 84215 Bratislava, Slovakia
| | - Sergey V. Adichtchev
- IA&E, Russian Academy of Sciences, 630090 Novosibirsk, Russia; (S.V.A.); (N.V.S.); (V.N.N.)
| | - Nikolay V. Surovtsev
- IA&E, Russian Academy of Sciences, 630090 Novosibirsk, Russia; (S.V.A.); (N.V.S.); (V.N.N.)
- Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Vladimir N. Novikov
- IA&E, Russian Academy of Sciences, 630090 Novosibirsk, Russia; (S.V.A.); (N.V.S.); (V.N.N.)
| | - Josef Bartoš
- Polymer Institute of SAS, Dúbravská Cesta 9, 84541 Bratislava, Slovakia;
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9
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Bichler KJ, Jakobi B, Sakai VG, Klapproth A, Mole RA, Schneider GJ. Short-Time Dynamics of PDMS- g-PDMS Bottlebrush Polymer Melts Investigated by Quasi-Elastic Neutron Scattering. Macromolecules 2020; 53:9553-9562. [PMID: 33191954 PMCID: PMC7659037 DOI: 10.1021/acs.macromol.0c01846] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 09/28/2020] [Indexed: 12/04/2022]
Abstract
We have studied the short-time dynamical behavior of polydimethylsiloxane (PDMS) bottlebrush polymers, PDMS-g-PDMS. The samples have similar backbone lengths but different side-chain lengths, resulting in a shape transition. Quasi-elastic neutron scattering was used to observe the dynamical changes inherent to these structural changes. The combination of data from three spectrometers enabled to follow the dynamics over broad frequency and temperature ranges, which included segmental relaxations and more localized motions. The latter, identified as the methyl group rotation, is described by a threefold jump model and shows higher activation energies compared to linear PDMS. The segmental relaxation times, τs, decrease with increasing molecular weight of the side chains but increase with momentum transfer, Q, following a power law, which suggests a non-Gaussian behavior for bottlebrush polymers.
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Affiliation(s)
- Karin J. Bichler
- Department
of Physics &Astronomy, Louisiana State
University, Baton
Rouge 70803, Louisiana, United States
| | - Bruno Jakobi
- Department
of Chemistry, Louisiana State University, Baton Rouge 70803, Louisiana, United States
| | - Victoria García Sakai
- ISIS
Facility, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Chilton, Didcot OX11 0QX, U.K.
| | - Alice Klapproth
- Australian
Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights 2234, New South Wales, Australia
| | - Richard A. Mole
- Australian
Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights 2234, New South Wales, Australia
| | - Gerald J. Schneider
- Department
of Physics &Astronomy, Louisiana State
University, Baton
Rouge 70803, Louisiana, United States
- Department
of Chemistry, Louisiana State University, Baton Rouge 70803, Louisiana, United States
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10
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Zorn R, Szymoniak P, Kolmangadi MA, Wolf M, Alentiev DA, Bermeshev M, Böhning M, Schönhals A. Low frequency vibrational density of state of highly permeable super glassy polynorbornenes - the Boson peak. Phys Chem Chem Phys 2020; 22:18381-18387. [PMID: 32794532 DOI: 10.1039/d0cp03360j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Inelastic incoherent neutron time-of-flight scattering was employed to measure the low frequency density of states for a series of addition polynorbornenes with bulky side groups. The rigid main chain in combination with the bulky side groups give rise to a microporosity of these polymers in the solid state. The microporosity characterized by the BET surfaces area varies systematically in the considered series. Such materials have some possible application as active separation layer in gas separation membranes. All investigated materials show excess contributions to the Debye type density of states characteristic for glasses known as Boson peak. The maximum position of the Boson peak shifts to lower frequency values with increasing microporosity. Data for PIM-1 and Matrimid included for comparison are in good agreement to this dependency. This result supports the sound wave interpretation of the Boson peak.
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Affiliation(s)
- Reiner Zorn
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1) and Institute for Biological Information Processing (IBI-8), 52425 Jülich, Germany
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11
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Zorn R, Lohstroh W, Zamponi M, Harrison WJ, Budd PM, Böhning M, Schönhals A. Molecular Mobility of a Polymer of Intrinsic Microporosity Revealed by Quasielastic Neutron Scattering. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c00963] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Reiner Zorn
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1), Jülich 52425,Germany
| | - Wiebke Lohstroh
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstraße 1, Garching 85748, Germany
| | - Michaela Zamponi
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at MLZ, Lichtenbergstr. 1, Garching 85748, Germany
| | - Wayne J. Harrison
- Department of Chemistry, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Peter M. Budd
- Department of Chemistry, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Martin Böhning
- BAM Bundesanstalt für Materialforschung und -prüfung, Unter den Eichen 87, Berlin 12205, Germany
| | - Andreas Schönhals
- BAM Bundesanstalt für Materialforschung und -prüfung, Unter den Eichen 87, Berlin 12205, Germany
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12
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Yildirim A, Krause C, Zorn R, Lohstroh W, Schneider GJ, Zamponi M, Holderer O, Frick B, Schönhals A. Complex molecular dynamics of a symmetric model discotic liquid crystal revealed by broadband dielectric, thermal and neutron spectroscopy. SOFT MATTER 2020; 16:2005-2016. [PMID: 32003764 DOI: 10.1039/c9sm02487e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The molecular dynamics of the triphenylene-based discotic liquid crystal HAT6 is investigated by broadband dielectric spectroscopy, advanced dynamical calorimetry and neutron scattering. Differential scanning calorimetry in combination with X-ray scattering reveals that HAT6 has a plastic crystalline phase at low temperatures, a hexagonally ordered liquid crystalline phase at higher temperatures and undergoes a clearing transition at even higher temperatures. The dielectric spectra show several relaxation processes: a localized γ-relaxation at lower temperatures and a so called α2-relaxation at higher temperatures. The relaxation rates of the α2-relaxation have a complex temperature dependence and bear similarities to a dynamic glass transition. The relaxation rates estimated by Hyper DSC, Fast Scanning calorimetry and AC Chip calorimetry have a different temperature dependence than the dielectric α2-relaxation and follow the VFT-behavior characteristic for glassy dynamics. Therefore, this process is called α1-relaxation. Its relaxation rates show a similarity with that of polyethylene. For this reason, the α1-relaxation is assigned to the dynamic glass transition of the alkyl chains in the intercolumnar space. Moreover, this process is not observed by dielectric spectroscopy, which supports its assignment. The α2-relaxation is assigned to small scale translatorial and/or small angle fluctuations of the cores. The neutron scattering data reveal two relaxation processes. The process observed at shorter relaxation times is assigned to the methyl group rotation. The second relaxation process at longer time scales agree in the temperature dependence of its relaxation rates with that of the dielectric γ-relaxation.
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Affiliation(s)
- Arda Yildirim
- Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany.
| | - Christina Krause
- Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany.
| | - Reiner Zorn
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1) and Institute for Complex Systems (ICS-1), 52425 Jülich, Germany
| | - Wiebke Lohstroh
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstraße 1, 85748 Garching, Germany
| | - Gerald J Schneider
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at MLZ, Lichtenbergstr. 1, 85748 Garching, Germany
| | - Michaela Zamponi
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at MLZ, Lichtenbergstr. 1, 85748 Garching, Germany
| | - Olaf Holderer
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at MLZ, Lichtenbergstr. 1, 85748 Garching, Germany
| | - Bernhard Frick
- Institut Laue-Langevin, 71 avenue des Martyrs, 38042 Grenoble Cedex 9, France
| | - Andreas Schönhals
- Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany.
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13
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Schönhals A, Zorn R, Frick B. Inelastic neutron spectroscopy as a tool to investigate nanoconfined polymer systems. POLYMER 2016. [DOI: 10.1016/j.polymer.2016.06.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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14
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al-Wahish A, Armitage D, al-Binni U, Hill B, Mills R, Jalarvo N, Santodonato L, Herwig KW, Mandrus D. A new apparatus design for high temperature (up to 950°C) quasi-elastic neutron scattering in a controlled gaseous environment. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:095102. [PMID: 26429475 DOI: 10.1063/1.4929580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 08/14/2015] [Indexed: 06/05/2023]
Abstract
A design for a sample cell system suitable for high temperature Quasi-Elastic Neutron Scattering (QENS) experiments is presented. The apparatus was developed at the Spallation Neutron Source in Oak Ridge National Lab where it is currently in use. The design provides a special sample cell environment under controlled humid or dry gas flow over a wide range of temperature up to 950 °C. Using such a cell, chemical, dynamical, and physical changes can be studied in situ under various operating conditions. While the cell combined with portable automated gas environment system is especially useful for in situ studies of microscopic dynamics under operational conditions that are similar to those of solid oxide fuel cells, it can additionally be used to study a wide variety of materials, such as high temperature proton conductors. The cell can also be used in many different neutron experiments when a suitable sample holder material is selected. The sample cell system has recently been used to reveal fast dynamic processes in quasi-elastic neutron scattering experiments, which standard probes (such as electrochemical impedance spectroscopy) could not detect. In this work, we outline the design of the sample cell system and present results demonstrating its abilities in high temperature QENS experiments.
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Affiliation(s)
- Amal al-Wahish
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996-1200, USA
| | - D Armitage
- Instrument and Source Design Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37861-6475, USA
| | - U al-Binni
- Department of Physics, Astronomy and Geology, Berry College, Mount Berry, Georgia 30149, USA
| | - B Hill
- Instrument and Source Design Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37861-6475, USA
| | - R Mills
- Instrument and Source Design Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37861-6475, USA
| | - N Jalarvo
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS), Outstation at Spallation Neutron Source (SNS), and Chemical and Engineering Materials Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6473, USA
| | - L Santodonato
- Instrument and Source Design Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37861-6475, USA
| | - K W Herwig
- Instrument and Source Design Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37861-6475, USA
| | - D Mandrus
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996-1200, USA
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15
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Burankova T, Hempelmann R, Fossog V, Ollivier J, Seydel T, Embs JP. Proton Diffusivity in the Protic Ionic Liquid Triethylammonium Triflate Probed by Quasielastic Neutron Scattering. J Phys Chem B 2015. [DOI: 10.1021/acs.jpcb.5b04000] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tatsiana Burankova
- Department
of Physical Chemistry, Saarland University, Saarbrücken, 66123, Germany
- Laboratory
for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen
PSI, Villigen 5232, Switzerland
| | - Rolf Hempelmann
- Department
of Physical Chemistry, Saarland University, Saarbrücken, 66123, Germany
| | - Verlaine Fossog
- Department
of Physical Chemistry, Saarland University, Saarbrücken, 66123, Germany
| | | | - Tilo Seydel
- Institut Laue-Langevin, Grenoble, 38000, France
| | - Jan P. Embs
- Laboratory
for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen
PSI, Villigen 5232, Switzerland
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16
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Chrissopoulou K, Anastasiadis SH. Effects of nanoscopic-confinement on polymer dynamics. SOFT MATTER 2015; 11:3746-3766. [PMID: 25869864 DOI: 10.1039/c5sm00554j] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The static and dynamic behavior of polymers in confinement close to interfaces can be very different from that in the bulk. Among the various geometries, intercalated nanocomposites, in which polymer films of ∼1 nm thickness reside between the parallel inorganic surfaces of layered silicates in a well-ordered multilayer, offer a unique avenue for the investigation of the effects of nanoconfinement on polymer structure and dynamics by utilizing conventional analytical techniques and macroscopic specimens. In this article, we provide a review of research activities mainly in our laboratory on polymer dynamics under severe confinement utilizing different polymer systems: polar and non-polar polymers were mixed with hydrophilic or organophilic silicates, respectively, whereas hyperbranched polymers were studied in an attempt to probe the effect of polymer-surface interactions by altering the number and the kinds of functional groups in the periphery of the branched polymers. The polymer dynamics was probed by quasielastic neutron scattering and dielectric relaxation spectroscopy and was compared with that of the polymers in the bulk. In all cases, very local sub-Tg processes related to the motion of side and/or end groups as well as the segmental α-relaxation were identified with distinct differences recorded between the bulk and the confined systems. Confinement was found not to affect the very local motion in the case of the linear chains whereas it made it easier for hyperbranched polymers due to modifications of the hydrogen bond network. The segmental relaxation in confinement becomes faster than that in the bulk, exhibits Arrhenius temperature dependence and is observed even below the bulk Tg due to reduced cooperativity in the confined systems.
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Affiliation(s)
- Kiriaki Chrissopoulou
- Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, P. O. Box 1527, 711 10 Heraklion Crete, Greece.
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17
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Ndao M, Lefort R, Cerclier CV, Busselez R, Morineau D, Frick B, Ollivier J, Kityk AV, Huber P. Molecular dynamics of pyrene based discotic liquid crystals confined in nanopores probed by incoherent quasielastic neutron scattering. RSC Adv 2014. [DOI: 10.1039/c4ra13032d] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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18
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Fotiadou S, Karageorgaki C, Chrissopoulou K, Karatasos K, Tanis I, Tragoudaras D, Frick B, Anastasiadis SH. Structure and Dynamics of Hyperbranched Polymer/Layered Silicate Nanocomposites. Macromolecules 2013. [DOI: 10.1021/ma302405q] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- S. Fotiadou
- Institute of Electronic Structure
and Laser, Foundation for Research and Technology—Hellas, P.O. Box 1527, 711 10 Heraklion, Crete, Greece
- Department of Chemical Engineering, Aristotle University of Thessaloniki, 541 24 Thessaloniki,
Greece
| | - C. Karageorgaki
- Institute of Electronic Structure
and Laser, Foundation for Research and Technology—Hellas, P.O. Box 1527, 711 10 Heraklion, Crete, Greece
- Department of Chemical Engineering, Aristotle University of Thessaloniki, 541 24 Thessaloniki,
Greece
| | - K. Chrissopoulou
- Institute of Electronic Structure
and Laser, Foundation for Research and Technology—Hellas, P.O. Box 1527, 711 10 Heraklion, Crete, Greece
| | - K. Karatasos
- Department of Chemical Engineering, Aristotle University of Thessaloniki, 541 24 Thessaloniki,
Greece
| | - I. Tanis
- Department of Chemical Engineering, Aristotle University of Thessaloniki, 541 24 Thessaloniki,
Greece
| | - D. Tragoudaras
- Department of Chemical Engineering, Aristotle University of Thessaloniki, 541 24 Thessaloniki,
Greece
| | - B. Frick
- Institut Laue Langevin (ILL), 6 rue Jules Horowitz, F38042 Grenoble, France
| | - S. H. Anastasiadis
- Institute of Electronic Structure
and Laser, Foundation for Research and Technology—Hellas, P.O. Box 1527, 711 10 Heraklion, Crete, Greece
- Department of Chemistry, University of Crete, P.O. Box 2208, 710 03 Heraklion
Crete, Greece
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19
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Hofmann T, Wallacher D, Mayorova M, Zorn R, Frick B, Huber P. Molecular dynamics of n-hexane: A quasi-elastic neutron scattering study on the bulk and spatially nanochannel-confined liquid. J Chem Phys 2012; 136:124505. [DOI: 10.1063/1.3696684] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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20
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Smuda C, Busch S, Schellenberg R, Unruh T. Methyl group dynamics in polycrystalline and liquid ubiquinone Q(0) studied by neutron scattering. J Phys Chem B 2009; 113:916-22. [PMID: 19123914 DOI: 10.1021/jp807601g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present a quasi-elastic neutron scattering (QENS) study on the methyl group dynamics of ubiquinone Q(0) in the solid and liquid state. For solid ubiquinone Q(0), the dynamics can be described with three Lorentzian functions in the framework of a jump model among three equidistant sites on a circle. According to the known molecular structure of Q(0) in the solid state, this is consistent with three nonequivalent methyl groups in the molecule. From the temperature-dependent analysis of the QENS spectra, the activation energies were determined. The barrier heights could be evaluated from librational bands in the inelastic part of the spectra. The results from neutron spectroscopy are compared to Gaussian 03 calculations leading to an assignment of the activation energies to the different methyl groups in Q(0). The dynamics of Q(0) in the liquid state is evaluated with a scattering function taking into account three different molecular motions. It is demonstrated that the temperature dependence of the long-range diffusion and isotropic rotational diffusion exhibit an Arrhenius-like behavior, whereas the process of methyl group rotation in the liquid phase is virtually free of a barrier.
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Affiliation(s)
- Christoph Smuda
- Forschungsneutronenquelle Heinz Maier-Leibnitz, Technische Universitat Munchen, Lichtenbergstrasse 1, D-85747 Garching b. Munchen, Germany
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21
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Smuda C, Busch S, Wagner B, Unruh T. Methyl group dynamics in glassy, polycrystalline, and liquid coenzyme Q10 studied by quasielastic neutron scattering. J Chem Phys 2008; 129:074507. [PMID: 19044783 DOI: 10.1063/1.2967188] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Christoph Smuda
- Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Technische Universitat Munchen, Lichtenbergstrasse 1, D-85747 Garching b. Munchen, Germany
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22
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Zorn R, Mayorova M, Richter D, Frick B. Inelastic neutron scattering study of a glass-forming liquid in soft confinement. SOFT MATTER 2008; 4:522-533. [PMID: 32907215 DOI: 10.1039/b713465g] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We have studied the microscopic dynamics of a glass-forming liquid in the soft confinement formed by microemulsion droplets using inelastic neutron scattering. The confined liquid was propylene glycol, the outer, hydrophobic phase was decalin, and the surfactant sodium dioctylsulfosuccinate (AOT) with the same composition used before with other spectroscopic methods [L.-M. Wang, F. He and R. Richert, Phys. Rev. Lett., 2004, 92, 95701]. The inelastic neutron scattering experiments were carried out on several time-of-flight and backscattering spectrometers to cover a large dynamical range. A Fourier transform was used to combine the data in terms of the intermediate scattering function S(Q,t) on a time range from 0.1 ps to 2 ns. By using two isotopic compositions the scattering of the glass-former was separated from that of the matrix liquids. In general we found an acceleration of the glass-transition-related α relaxation in confinement combined with a moderate broadening of the relaxation time distribution. This effect is most pronounced for low temperatures (≤250 K) and fades out at about 270-300 K. In addition, inelastic scattering allowed us to observe the motion of the methyl group of propylene glycol and the vibrational dynamics in the glass. For the methyl group reorientation we also found an acceleration but a narrowing of the relaxation time distribution. The vibrational dynamics show that the glass-typical 'boson peak' of bulk propylene glycol is completely washed out in the microemulsion in contrast to all earlier studies using hard confinement, which observed a low-frequency cut-off.
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Affiliation(s)
- Reiner Zorn
- Forschungszentrum Julich, IFF, D-52425, Julich, Germany
| | | | | | - Bernhard Frick
- Institut Laue-Langevin, B.P. 156X, F-38042, Grenoble, France
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23
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Chrissopoulou K, Anastasiadis SH, Giannelis EP, Frick B. Quasielastic neutron scattering of poly(methyl phenyl siloxane) in the bulk and under severe confinement. J Chem Phys 2007; 127:144910. [DOI: 10.1063/1.2775449] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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24
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Kirstein O, Prager M, Grimm H, Buchsteiner A, Wischnewski A. Quasielastic neutron scattering experiments including activation energies and mathematical modeling of methyl halide dynamics. J Chem Phys 2007; 127:094504. [PMID: 17824745 DOI: 10.1063/1.2760205] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Quasielastic neutron scattering experiments were carried out using the multichopper time-of-flight spectrometer V3 at the Hahn-Meitner Institut, Germany and the backscattering spectrometer at Forschungszentrum Julich, Germany. Activation energies for CH(3)X, X=F, Cl, Br, and I, were obtained. In combination with results from previous inelastic neutron scattering experiments the data were taken to describe the dynamics of the halides in terms of two different models, the single particle model and the coupling model. Coupled motions of methyl groups seem to explain the dynamics of the methyl fluoride and chloride; however, the coupling vanishes with the increase of the mass of the halide atom in CH(3)Br and CH(3)I.
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Affiliation(s)
- O Kirstein
- Bragg Institute, Australian Nuclear Science and Technology Organisation, Menai, New South Wales 2234, Australia.
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25
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Chen C, Maranas JK, García-Sakai V. Local Dynamics of Syndiotactic Poly(methyl methacrylate) Using Molecular Dynamics Simulation. Macromolecules 2006. [DOI: 10.1021/ma0610562] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Chunxia Chen
- Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Janna K. Maranas
- Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Victoria García-Sakai
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8562
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26
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Colmenero J, Moreno AJ, Alegría A. Neutron scattering investigations on methyl group dynamics in polymers. Prog Polym Sci 2005. [DOI: 10.1016/j.progpolymsci.2005.08.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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27
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Adams MA, Gabrys BJ, Zajac WM, Peiffer DG. High-Resolution Incoherent Inelastic Neutron Scattering Spectra of Polyisobutylene and Polyisoprene. Macromolecules 2004. [DOI: 10.1021/ma049651w] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mark A. Adams
- The ISIS Pulsed Neutron Scattering Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX, U.K.; Department of Materials, University of Oxford, Oxford, OX1 3PH, U.K.; The H. Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31-342 Kraków, Poland; and ExxonMobil Research and Engineering Co., Annandale, New Jersey 08801
| | - Barbara J. Gabrys
- The ISIS Pulsed Neutron Scattering Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX, U.K.; Department of Materials, University of Oxford, Oxford, OX1 3PH, U.K.; The H. Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31-342 Kraków, Poland; and ExxonMobil Research and Engineering Co., Annandale, New Jersey 08801
| | - Wojciech M. Zajac
- The ISIS Pulsed Neutron Scattering Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX, U.K.; Department of Materials, University of Oxford, Oxford, OX1 3PH, U.K.; The H. Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31-342 Kraków, Poland; and ExxonMobil Research and Engineering Co., Annandale, New Jersey 08801
| | - Dennis G. Peiffer
- The ISIS Pulsed Neutron Scattering Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX, U.K.; Department of Materials, University of Oxford, Oxford, OX1 3PH, U.K.; The H. Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31-342 Kraków, Poland; and ExxonMobil Research and Engineering Co., Annandale, New Jersey 08801
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28
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Russina O, Triolo A, Aihara Y, Telling MTF, Grimm H. Quasi-Elastic Neutron Scattering Investigation of Dynamics in Polymer Electrolytes. Macromolecules 2004. [DOI: 10.1021/ma0493574] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Olga Russina
- Hahn-Meitner Institut, Glienicker Str. 100, D-14109 Berlin, Germany; Istituto per i Processi Chimico-Fisici-CNR, via La Farina 237, 98123 Messina, Italy; Yuasa Corporation, 4-5-1 Ohgi-cho, Odawara 250-0001, Japan; ISIS Facility, Rutherford Appleton Laboratory, Chilton, OXON, U.K.; and Institut für Festkörperforschung, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
| | - Alessandro Triolo
- Hahn-Meitner Institut, Glienicker Str. 100, D-14109 Berlin, Germany; Istituto per i Processi Chimico-Fisici-CNR, via La Farina 237, 98123 Messina, Italy; Yuasa Corporation, 4-5-1 Ohgi-cho, Odawara 250-0001, Japan; ISIS Facility, Rutherford Appleton Laboratory, Chilton, OXON, U.K.; and Institut für Festkörperforschung, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
| | - Yuichi Aihara
- Hahn-Meitner Institut, Glienicker Str. 100, D-14109 Berlin, Germany; Istituto per i Processi Chimico-Fisici-CNR, via La Farina 237, 98123 Messina, Italy; Yuasa Corporation, 4-5-1 Ohgi-cho, Odawara 250-0001, Japan; ISIS Facility, Rutherford Appleton Laboratory, Chilton, OXON, U.K.; and Institut für Festkörperforschung, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
| | - Mark T. F. Telling
- Hahn-Meitner Institut, Glienicker Str. 100, D-14109 Berlin, Germany; Istituto per i Processi Chimico-Fisici-CNR, via La Farina 237, 98123 Messina, Italy; Yuasa Corporation, 4-5-1 Ohgi-cho, Odawara 250-0001, Japan; ISIS Facility, Rutherford Appleton Laboratory, Chilton, OXON, U.K.; and Institut für Festkörperforschung, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
| | - Hans Grimm
- Hahn-Meitner Institut, Glienicker Str. 100, D-14109 Berlin, Germany; Istituto per i Processi Chimico-Fisici-CNR, via La Farina 237, 98123 Messina, Italy; Yuasa Corporation, 4-5-1 Ohgi-cho, Odawara 250-0001, Japan; ISIS Facility, Rutherford Appleton Laboratory, Chilton, OXON, U.K.; and Institut für Festkörperforschung, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
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29
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Narros A, Alvarez F, Arbe A, Colmenero J, Richter D, Farago B. Hydrogen motions in the α-relaxation regime of poly(vinyl ethylene): A molecular dynamics simulation and neutron scattering study. J Chem Phys 2004; 121:3282-94. [PMID: 15291640 DOI: 10.1063/1.1772761] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The hydrogen motion in poly(vinyl ethylene) (1,2-polybutadiene) in the alpha-relaxation regime has been studied by combining neutron spin echo (NSE) measurements on a fully protonated sample and fully atomistic molecular dynamics simulations. The almost perfect agreement between experiment and simulation results validates the simulated cell. A crossover from Gaussian to non-Gaussian behavior is observed for the intermediate scattering function obtained from both NSE measurements and simulations. This crossover takes place at unusually low Q values, well below the first maximum of the static structure factor. Such anomalous deviation from Gaussian behavior can be explained by the intrinsic dynamic heterogeneity arising from the differences in the dynamics of the different protons in this system. Side group hydrogens show a markedly higher mobility than main chain protons. Taking advantage of the simulations we have investigated the dynamic features of all different types of hydrogens in the sample. Considering each kind of proton in an isolated way, deviations from Gaussian behavior are also found. These can be rationalized in the framework of a simple picture based on the existence of a distribution of discrete jumps underlying the atomic motions in the alpha process.
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Affiliation(s)
- A Narros
- Departamento de Física de Materiales UPV/EHU, Apartado 1072, 20080 San Sebastián, Spain
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30
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Arrighi V, Gagliardi S, Zhang C, Ganazzoli F, Higgins JS, Ocone R, Telling MTF. A Unified Picture of the Local Dynamics of Poly(dimethylsiloxane) across the Melting Point. Macromolecules 2003. [DOI: 10.1021/ma034843x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Valeria Arrighi
- Chemistry, School of Engineering and Physical Sciences, Heriot-Watt University, EH14 4AS Edinburgh, UK
| | - Simona Gagliardi
- Chemistry, School of Engineering and Physical Sciences, Heriot-Watt University, EH14 4AS Edinburgh, UK
| | - Chuhong Zhang
- Chemistry, School of Engineering and Physical Sciences, Heriot-Watt University, EH14 4AS Edinburgh, UK
| | - Fabio Ganazzoli
- Dipartimento di Chimica, Materiali e Ing. Chimica “Giulio Natta“, Sez. Chimica Politecnico di Milano via L. Mancinelli 7, 20131 Milano, Italy
| | - Julia S. Higgins
- Department of Chemical Engineering and Chemical Technology, Imperial College, South Kensington Campus, London, SW7 2AZ, UK
| | - Raffaella Ocone
- Chemical Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, EH14 4AS Edinburgh, UK
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31
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Intermediate length scale dynamics in glass forming polymers: coherent and incoherent quasielastic neutron scattering results on polyisobutylene. Chem Phys 2003. [DOI: 10.1016/s0301-0104(03)00095-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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32
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Arbe A, Colmenero J, Alvarez F, Monkenbusch M, Richter D, Farago B, Frick B. Experimental evidence by neutron scattering of a crossover from Gaussian to non-Gaussian behavior in the alpha relaxation of polyisoprene. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2003; 67:051802. [PMID: 12786170 DOI: 10.1103/physreve.67.051802] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2002] [Indexed: 05/24/2023]
Abstract
We report incoherent quasielastic neutron scattering experiments exploring the alpha-relaxation range in polyisoprene over an unprecedented range in momentum transfer Q. The data corroborate and validate earlier molecular dynamics simulations and reveal the existence of a crossover from Gaussian to non-Gaussian character of the main chain protons self-correlation function in the alpha-relaxation regime. The real challenge of the experiment was to push the neutron techniques to cover a Q range as wide as possible. By combining two neutron spin echo spectrometers and a backscattering instrument, we have been able to study the dynamics in a Q range of 0.1 < or = Q < or = 4.7 A(-1). In the low-Q regime the shape of the relaxation function was found to be related to the dispersion of the relaxation times as predicted by the Gaussian assumption. At short distances or large Q, this relationship is strongly violated indicating a non-Gaussian regime. We have performed a detailed comparison between the experiments and simulations at different temperatures and found, apart from a temperature shift, complete agreement. Combining experiments and simulations led to a consistent interpretation in terms of a distribution of jumps underlying the diffusive motion of protons in the alpha process. This model leads to a time-dependent non-Gaussianity parameter that agrees nearly quantitatively with the simulations and exhibits all features resolved so far from various simulations.
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Affiliation(s)
- A Arbe
- Unidad Física de Materiales, CSIC-UPV/EHU, Apartado 1072, 20080 San Sebastián, Spain
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33
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Ahumada O, Theodorou DN, Triolo A, Arrighi V, Karatasos C, Ryckaert JP. Segmental Dynamics of Atactic Polypropylene As Revealed by Molecular Simulations and Quasielastic Neutron Scattering. Macromolecules 2002. [DOI: 10.1021/ma011807u] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Oscar Ahumada
- Department of Chemical Engineering, University of Patras and ICE/HT-FORTH, GR-26500 Patras, Greece, Chemistry Department, Heriot-Watt University Edinburgh, EH14 4AS, United Kingdom, and Laboratoire de Physique des Polymères, CP223, Université Libre de Bruxelles, Boulevard de Triomphe, B-1050 Bruxelles, Belgique
| | - Doros N. Theodorou
- Department of Chemical Engineering, University of Patras and ICE/HT-FORTH, GR-26500 Patras, Greece, Chemistry Department, Heriot-Watt University Edinburgh, EH14 4AS, United Kingdom, and Laboratoire de Physique des Polymères, CP223, Université Libre de Bruxelles, Boulevard de Triomphe, B-1050 Bruxelles, Belgique
| | - Alessandro Triolo
- Department of Chemical Engineering, University of Patras and ICE/HT-FORTH, GR-26500 Patras, Greece, Chemistry Department, Heriot-Watt University Edinburgh, EH14 4AS, United Kingdom, and Laboratoire de Physique des Polymères, CP223, Université Libre de Bruxelles, Boulevard de Triomphe, B-1050 Bruxelles, Belgique
| | - Valeria Arrighi
- Department of Chemical Engineering, University of Patras and ICE/HT-FORTH, GR-26500 Patras, Greece, Chemistry Department, Heriot-Watt University Edinburgh, EH14 4AS, United Kingdom, and Laboratoire de Physique des Polymères, CP223, Université Libre de Bruxelles, Boulevard de Triomphe, B-1050 Bruxelles, Belgique
| | - Costas Karatasos
- Department of Chemical Engineering, University of Patras and ICE/HT-FORTH, GR-26500 Patras, Greece, Chemistry Department, Heriot-Watt University Edinburgh, EH14 4AS, United Kingdom, and Laboratoire de Physique des Polymères, CP223, Université Libre de Bruxelles, Boulevard de Triomphe, B-1050 Bruxelles, Belgique
| | - Jean-Paul Ryckaert
- Department of Chemical Engineering, University of Patras and ICE/HT-FORTH, GR-26500 Patras, Greece, Chemistry Department, Heriot-Watt University Edinburgh, EH14 4AS, United Kingdom, and Laboratoire de Physique des Polymères, CP223, Université Libre de Bruxelles, Boulevard de Triomphe, B-1050 Bruxelles, Belgique
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