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Gupta S, Fischer JKH, Lunkenheimer P, Loidl A, Novak E, Jalarvo N, Ohl M. Effect of adding nanometre-sized heterogeneities on the structural dynamics and the excess wing of a molecular glass former. Sci Rep 2016; 6:35034. [PMID: 27725747 PMCID: PMC5057163 DOI: 10.1038/srep35034] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 09/21/2016] [Indexed: 11/17/2022] Open
Abstract
We present the relaxation dynamics of glass-forming glycerol mixed with 1.1 nm sized polyhedral oligomeric silsesquioxane (POSS) molecules using dielectric spectroscopy (DS) and two different neutron scattering (NS) techniques. Both, the reorientational dynamics as measured by DS and the density fluctuations detected by NS reveal a broadening of the α relaxation when POSS molecules are added. Moreover, we find a significant slowing down of the α-relaxation time. These effects are in accord with the heterogeneity scenario considered for the dynamics of glasses and supercooled liquids. The addition of POSS also affects the excess wing in glycerol arising from a secondary relaxation process, which seems to exhibit a dramatic increase in relative strength compared to the α relaxation.
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Affiliation(s)
- S Gupta
- Juelich Centre for Neutron science (JCNS) outstation at SNS, POB 2008, 1 Bethel Valley Road, TN 37831, Oak Ridge, USA.,Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge National Laboratory (ORNL), POB 2008, 1 Bethel Valley Road, TN 37831, Oak Ridge, USA.,Department of Chemistry and Macromolecular Studies Group, Louisiana State University, Baton Rouge, LA 70803, USA
| | - J K H Fischer
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - P Lunkenheimer
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - A Loidl
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
| | - E Novak
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, USA
| | - N Jalarvo
- Juelich Centre for Neutron science (JCNS) outstation at SNS, POB 2008, 1 Bethel Valley Road, TN 37831, Oak Ridge, USA.,Chemical and Engineering Materials Division, Oak Ridge National Laboratory (ORNL), PO BOX 2008 MS6473, TN 37831, Oak Ridge, USA
| | - M Ohl
- Juelich Centre for Neutron science (JCNS) outstation at SNS, POB 2008, 1 Bethel Valley Road, TN 37831, Oak Ridge, USA.,Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge National Laboratory (ORNL), POB 2008, 1 Bethel Valley Road, TN 37831, Oak Ridge, USA
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2
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Rault J. The Modified VFT law of glass former materials under pressure: Part II: Relation with the equation of state. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2015; 38:91. [PMID: 26314261 DOI: 10.1140/epje/i2015-15091-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 07/16/2015] [Indexed: 06/04/2023]
Abstract
The dynamical properties of glass formers (GFs) as a function of P, V, and T are reanalyzed in relation with the equations of state (EOS) proposed recently (Eur. Phys. J. E 37, 113 (2014)). The relaxation times τ of the cooperative non-Arrhenius α process and the individual Arrhenius β process are coupled via the Kohlrausch exponent n S(T, P). In the model n S is the sigmoidal logistic function depending on T (and P, and the α relaxation time τ α of GFs above T g verifies the pressure-modified VFT law: log τ α ∼ E β /nsRT, which can be put into a form with separated variables: log τ α ∼ f(T)g(P). From the variation of n S and τ α with T and P the Vogel temperature T 0 (τ α → ∝, n S = 0) and the crossover temperature (also called the merging or splitting temperature) T B (τ α ∼ τ β, n S ∼ 1) are determined. The proposed sm-VFT equation fits with excellent accuracy the experimental data of fragile and strong GFs under pressure. The properties generally observed in organic mineral and metallic GFs are explained: a) The Vogel temperature is independent of P (as suggested by the EOS properties), the crossover is pressure-dependent. b) In crystallizable GFs the T B (P) and Clapeyron curves T m(P) coincide. c) The α and β processes have the same ratio of the activation energies and volume, E*/V* (T- and P-independent), the compensation law is observed, this ratio depends on the anharmonicity Slater-Grüneisen parameter and on the critical pressure P* deduced from the EOS. d) The properties of the Fan Structure of the Tangents (FST) to the isotherms and isobars curves log τ versus P and T and to the isochrones curves P(T). e) The scaling law log τ = f(V (Λ) ) and the relation between Γ and γ. We conclude that these properties should be studied in detail in GFs submitted to negative pressures.
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Affiliation(s)
- Jacques Rault
- Physique des solides, Université de Paris-Sud, 91405, Orsay, France,
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Sillrén P, Matic A, Karlsson M, Koza M, Maccarini M, Fouquet P, Götz M, Bauer T, Gulich R, Lunkenheimer P, Loidl A, Mattsson J, Gainaru C, Vynokur E, Schildmann S, Bauer S, Böhmer R. Liquid 1-propanol studied by neutron scattering, near-infrared, and dielectric spectroscopy. J Chem Phys 2014; 140:124501. [PMID: 24697453 DOI: 10.1063/1.4868556] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Liquid monohydroxy alcohols exhibit unusual dynamics related to their hydrogen bonding induced structures. The connection between structure and dynamics is studied for liquid 1-propanol using quasi-elastic neutron scattering, combining time-of-flight and neutron spin-echo techniques, with a focus on the dynamics at length scales corresponding to the main peak and the pre-peak of the structure factor. At the main peak, the structural relaxation times are probed. These correspond well to mechanical relaxation times calculated from literature data. At the pre-peak, corresponding to length scales related to H-bonded structures, the relaxation times are almost an order of magnitude longer. According to previous work [C. Gainaru, R. Meier, S. Schildmann, C. Lederle, W. Hiller, E. Rössler, and R. Böhmer, Phys. Rev. Lett. 105, 258303 (2010)] this time scale difference is connected to the average size of H-bonded clusters. The relation between the relaxation times from neutron scattering and those determined from dielectric spectroscopy is discussed on the basis of broad-band permittivity data of 1-propanol. Moreover, in 1-propanol the dielectric relaxation strength as well as the near-infrared absorbance reveal anomalous behavior below ambient temperature. A corresponding feature could not be found in the polyalcohols propylene glycol and glycerol.
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Affiliation(s)
- P Sillrén
- Department of Applied Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - A Matic
- Department of Applied Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - M Karlsson
- Department of Applied Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - M Koza
- Institut Laue Langevin, 6, rue Jules Horowitz, BP 156, 38042 Grenoble Cedex 9, France
| | - M Maccarini
- Institut Laue Langevin, 6, rue Jules Horowitz, BP 156, 38042 Grenoble Cedex 9, France
| | - P Fouquet
- Institut Laue Langevin, 6, rue Jules Horowitz, BP 156, 38042 Grenoble Cedex 9, France
| | - M Götz
- Experimental Physics V, University of Augsburg, 86135 Augsburg, Germany
| | - Th Bauer
- Experimental Physics V, University of Augsburg, 86135 Augsburg, Germany
| | - R Gulich
- Experimental Physics V, University of Augsburg, 86135 Augsburg, Germany
| | - P Lunkenheimer
- Experimental Physics V, University of Augsburg, 86135 Augsburg, Germany
| | - A Loidl
- Experimental Physics V, University of Augsburg, 86135 Augsburg, Germany
| | - J Mattsson
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - C Gainaru
- Fakultät für Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - E Vynokur
- Fakultät für Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - S Schildmann
- Fakultät für Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - S Bauer
- Fakultät für Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - R Böhmer
- Fakultät für Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
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Fragiadakis D, Roland CM. Characteristics of the Johari-Goldstein process in rigid asymmetric molecules. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:042307. [PMID: 24229172 DOI: 10.1103/physreve.88.042307] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Indexed: 06/02/2023]
Abstract
Molecular dynamics simulations were carried out on a Lennard-Jones binary mixture of rigid (fixed bond length) diatomic molecules. The translational and rotational correlation functions, and the corresponding susceptibilities, exhibit two relaxation processes: the slow structural relaxation (α dynamics) and a higher frequency secondary relaxation. The latter is a Johari-Goldstein (JG) process, by its definition of involving all parts of the molecule. It shows several properties characteristic of the JG relaxation: (1) merging with the α relaxation at high temperature; (2) a change in temperature dependence of its relaxation strength on vitrification; (3) a separation in frequency from the α peak that correlates with the breadth of the α dispersion; and (4) sensitivity to volume, pressure, and physical aging. These properties can be used to determine whether a secondary relaxation in a real material is an authentic JG process, rather than more trivial motion involving intramolecular degrees of freedom. The latter has no connection to the glass transition, whereas the JG relaxation is closely related to structural relaxation, and thus can provide new insights into the phenomenon.
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Affiliation(s)
- D Fragiadakis
- Naval Research Laboratory, Chemistry Division, Code 6120, Washington, DC 20375-5342, USA
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Casalini R, Snow AW, Roland CM. Temperature Dependence of the Johari–Goldstein Relaxation in Poly(methyl methacrylate) and Poly(thiomethyl methacrylate). Macromolecules 2012. [DOI: 10.1021/ma3021322] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- R. Casalini
- Chemistry Division, Naval Research Laboratory, Code 6120, Washington, D.C. 20375-5342, United States
| | - A. W. Snow
- Chemistry Division, Naval Research Laboratory, Code 6120, Washington, D.C. 20375-5342, United States
| | - C. M. Roland
- Chemistry Division, Naval Research Laboratory, Code 6120, Washington, D.C. 20375-5342, United States
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Saito M, Kitao S, Kobayashi Y, Kurokuzu M, Yoda Y, Seto M. Slow processes in supercooled o-terphenyl: relaxation and decoupling. PHYSICAL REVIEW LETTERS 2012; 109:115705. [PMID: 23005649 DOI: 10.1103/physrevlett.109.115705] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Indexed: 06/01/2023]
Abstract
We mapped the relaxation times of inter- and intramolecular correlations in o-terphenyl by a quasielastic scattering method using nuclear resonant scattering of synchrotron radiation. From the obtained map, we found that the slow β process is decoupled from the α process at 278 K, and this temperature is clearly below the previous decoupling temperature of 290 K, at which the α-relaxation dynamics changes. Then, it was also concluded that sufficient solidlike condition achieved by further cooling from 290 K is required to decouple the slow β process from the α process and, due to the difference of the length scales between the α and the slow β processes, these two averaged relaxation times <τ> are concluded not to cross as an extrapolation assumed so far. Furthermore, evidence of the restricted dynamics of the slow β process could be obtained as an anomalous momentum transfer (q) dependence of <τ>(<τ> ∝q(-2.9)) at 265 K, observed at q values of 18-48 nm(-1).
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Affiliation(s)
- Makina Saito
- Research Reactor Institute, Kyoto University, Kumatori, Osaka 590-0494, Japan
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Bogoslovov RB, Hogan TE, Roland CM. Clarifying the Molecular Weight Dependence of the Segmental Dynamics of Polybutadiene. Macromolecules 2010. [DOI: 10.1021/ma9026965] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- R. B. Bogoslovov
- Naval Research Laboratory, Code 6120, Washington, D.C. 20375-5342
| | - T. E. Hogan
- Bridgestone Americas, Center for Research and Technology, 1200 Firestone Parkway, Akron, Ohio 44317-0001
| | - C. M. Roland
- Naval Research Laboratory, Code 6120, Washington, D.C. 20375-5342
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Sağlanmak N, Nielsen AI, Olsen NB, Dyre JC, Niss K. An electrical circuit model of the alpha-beta merging seen in dielectric relaxation of ultraviscous liquids. J Chem Phys 2010; 132:024503. [DOI: 10.1063/1.3270164] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Neslihan Sağlanmak
- Department of Sciences, DNRF Center Glass and Time, IMFUFA, Roskilde University, Universitetsvej 1, Roskilde 4000, Denmark
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Schroeder MJ, Ngai KL, Michael Roland C. The nearly constant loss, Johari-Goldstein β-relaxation, and α-relaxation of 1,4-polybutadiene. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/polb.21051] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Fujima T, Frusawa H, Ito K. Merging of alpha and slow beta relaxation in supercooled liquids. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2002; 66:031503. [PMID: 12366116 DOI: 10.1103/physreve.66.031503] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2001] [Revised: 05/14/2002] [Indexed: 05/23/2023]
Abstract
Dielectric relaxation spectroscopy (1 Hz - 20 GHz) has been performed on supercooled glass-formers from the temperature of glass transition (T(g)) up to that of melting. Precise measurements particularly in the frequencies of MHz order have revealed that the temperature dependences of secondary beta relaxation times in well above T(g) deviate from the Arrhenius relation below T(g): the beta process does not merge with the alpha process around the dynamical crossover temperature in contradiction to previously speculated extrapolations.
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Affiliation(s)
- Takuya Fujima
- Department of Applied Physics, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
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Corezzi S, Beiner M, Huth H, Schröter K, Capaccioli S, Casalini R, Fioretto D, Donth E. Two crossover regions in the dynamics of glass forming epoxy resins. J Chem Phys 2002. [DOI: 10.1063/1.1486214] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Grimau M, Laredo E, Pérez Y. MC, Bello A. Study of dielectric relaxation modes in poly(ε-caprolactone): Molecular weight, water sorption, and merging effects. J Chem Phys 2001. [DOI: 10.1063/1.1355288] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Köplinger J, Kasper G, Hunklinger S. Glass transition in chlorobenzene–decalin under pressure. J Chem Phys 2000. [DOI: 10.1063/1.1288904] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Bello A, Laredo E, Grimau M, Nogales A, Ezquerra TA. Relaxation time distribution from time and frequency domain dielectric spectroscopy in poly(aryl ether ether ketone). J Chem Phys 2000. [DOI: 10.1063/1.481862] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Robertson CG, Roland CM. Breadth of the α-Relaxation Function in 1,4-Polybutadiene. Macromolecules 2000. [DOI: 10.1021/ma991630s] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- C. G. Robertson
- Chemistry Division, Code 6120, Naval Research Laboratory, Washington, D.C. 20375-5342
| | - C. M. Roland
- Chemistry Division, Code 6120, Naval Research Laboratory, Washington, D.C. 20375-5342
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