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Chandra A, Meyer WH. Dielectric relaxation studies of low thermal expansion polymer composites. J Appl Polym Sci 2012. [DOI: 10.1002/app.38455] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Sharifi S, Capaccioli S, Lucchesi M, Rolla P, Prevosto D. Temperature and pressure dependence of secondary process in an epoxy system. J Chem Phys 2011; 134:044510. [PMID: 21280751 DOI: 10.1063/1.3518972] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Dielectric spectroscopy as a function of temperature and pressure was used to study the secondary relaxation in poly [(phenyl glycidyl ether)-co-formaldehyde] at hydrostatic pressure up to 600 MPa and at different temperatures between 315 and 243 K. From the analysis of the isothermal measurements, we observe that the activation volume of the secondary relaxation has nonmonotonic temperature dependence with a maximum at the temperature of the glass transition at ambient pressure. An interpretation in terms of mean hole volume dispersion is proposed based on literature data. Moreover, from isobaric data, we studied the effect of pressure on activation entropy and enthalpy of the secondary relaxation evidencing its local nature but also the presence of a certain complexity of the motion, which supports the idea that this process reflects the motion of a large part of the molecule.
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Affiliation(s)
- Soheil Sharifi
- Dipartimento di Fisica, Università di Pisa, Largo B. Pontecorvo 3, 1-56127 Pisa, Italy
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Gaborieau M, Graf R, Kahle S, Pakula T, Spiess HW. Chain Dynamics in Poly(n-alkyl acrylates) by Solid-State NMR, Dielectric, and Mechanical Spectroscopies. Macromolecules 2007. [DOI: 10.1021/ma0706531] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marianne Gaborieau
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Robert Graf
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Stefan Kahle
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Tadeusz Pakula
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Hans W. Spiess
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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Sudo S, Shimomura M, Kanari K, Shinyashiki N, Yagihara S. Broadband dielectric study of the glass transition in poly(ethyleneglycol)-water mixture. J Chem Phys 2006; 124:044901. [PMID: 16460206 DOI: 10.1063/1.2149860] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We performed broadband dielectric measurements of a polyethyleneglycol-water mixture in the frequency range between 10 GHz and 1 microHz and the temperature range between 300 and 133 K. One relaxation process is observed throughout the whole temperature range. The temperature dependence of the relaxation time clearly obeys the Vogel-Fulcher law above 183 K, and the Arrhenius law below 183 K. This observed relaxation process is the secondary process, and the primary process related to the glass transition is masked by the low-frequency ionic contribution below 183 K. The glass transition concerned with the masked primary process leads to the Vogel-Fulcher to Arrhenius transition of the secondary process.
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Affiliation(s)
- S Sudo
- Department of Physics, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan
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Kahle S, Gapinski J, Hinze G, Patkowski A, Meier G. A comparison of relaxation processes in structurally related van der Waals glass formers: The role of internal degrees of freedom. J Chem Phys 2005; 122:074506. [PMID: 15743253 DOI: 10.1063/1.1846653] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Depolarized dynamic light scattering (DLS), dielectric relaxation (DS), and deuterium NMR studies of fragile van der Waals glass forming liquids phenylphthalein-dimethylether (PDE) and cresolphthalein-dimethylether (KDE) are presented. In PDE a new dielectric loss process was found, which can be attributed to the 180 degrees flip of the phenyl rings. The previous finding that the distribution of the structural relaxation times measured for PDE and KDE by DS is substantially narrower than that measured by DLS is explained by partial decoupling of the dynamics of the dipole moment from the structural relaxation of the sample. The dynamics of PDE and KDE is compared with the previous studies of two other structurally similar liquids: 1,1'-di(4-methoxy-5-methylphenyl)cyclohexane (BMMPC) and 1,1'-bis(p-methoxyphenyl)cyclohexane (BMPC) in order to relate dynamical features with the chemical structure of the material. The evidence for the intramolecular character of the secondary relaxations observed in BMPC and PDE is presented.
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Affiliation(s)
- S Kahle
- Institut fuer Festkörperforschung, Forschungszentrum Jülich, Postfach 1913, 52425 Jülich, Germany
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Sudo S, Tsubotani S, Shimomura M, Shinyashiki N, Yagihara S. Dielectric study of the α and β processes in supercooled ethylene glycol oligomer–water mixtures. J Chem Phys 2004; 121:7332-40. [PMID: 15473803 DOI: 10.1063/1.1796232] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Broadband dielectric measurements for 65 wt % ethylene glycol oligomer (EGO)-water mixtures with one to six repeat units of EGO molecules were performed in the frequency range of 10 microHz-10 GHz and the temperature range of 128-298 K. In the case of the water-EGO mixtures with one and two repeat units of the EGO molecule (small EGO), the shape of the dielectric loss peak of the primary process is asymmetrical about the logarithm of the frequency of maximum loss above the crossover temperature, T(C). The asymmetric process continues to the alpha process at a low frequency, and an additional beta process appears in the frequency range higher than that of the alpha process below T(C). In contrast, the water-EGO mixtures with three or more repeat units of the EGO molecule (large EGO) show a broad and symmetrical loss peak of the primary process above T(C). The symmetric process continues to the beta process, and an additional alpha process appears in the frequency range lower than that of the beta process below T(C). These different scenarios of the alpha-beta separation related to the shape of the loss peak above T(C) are a result of the difference in the cooperative motion of water and solute molecules. The solute and water molecules move cooperatively in the small EGO-water mixtures above T(C), and this cooperative motion leads to the asymmetric loss peak above T(C) and the alpha process below T(C). For the large EGO-water mixtures, the spatially restricted motion of water confined by solute molecules leads to the symmetric loss peak above T(C) and the beta process below T(C).
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Affiliation(s)
- Seiichi Sudo
- Department of Physics, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan
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Ngai KL, Capaccioli S. Relation between the activation energy of the Johari-Goldstein beta relaxation and T(g) of glass formers. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2004; 69:031501. [PMID: 15089297 DOI: 10.1103/physreve.69.031501] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2003] [Indexed: 05/24/2023]
Abstract
For glass-forming substances, we show that the ratio E(beta)/RT(g) can be predicted quantitatively from the coupling model. Here E(beta) is the glassy state activation enthalpy of the Johari-Goldstein beta relaxation, T(g) is the glass transition temperature of the alpha relaxation, and R is the gas constant. The calculated value is in good agreement with the experimental value in many glass formers. The results locate the origin of this cross correlation between E(beta) of the Johari-Goldstein beta relaxation and T(g) of the alpha relaxation, although there are some notable exceptions to this cross correlation.
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Affiliation(s)
- K L Ngai
- Naval Research Laboratory, Washington, DC 20375-5320, USA
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Minoguchi A, Kitai K, Nozaki R. Difference and similarity of dielectric relaxation processes among polyols. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2003; 68:031501. [PMID: 14524771 DOI: 10.1103/physreve.68.031501] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2002] [Revised: 03/25/2003] [Indexed: 05/24/2023]
Abstract
Complex permittivity measurements were performed on sorbitol, xylitol, and sorbitol-xylitol mixture in the supercooled liquid state in an extremely wide frequency range from 10 microHz to 500 MHz at temperatures near and above the glass transition temperature. We determined detailed behavior of the relaxation parameters such as relaxation frequency and broadening against temperature not only for the alpha process but also for the beta process above the glass transition temperature, to the best of our knowledge, for the first time. Since supercooled liquids are in the quasi-equilibrium state, the behavior of all the relaxation parameters for the beta process can be compared among the polyols as well as those for the alpha process. The relaxation frequencies of the alpha processes follow the Vogel-Fulcher-Tammann manner and the loci in the Arrhenius diagram are different corresponding to the difference of the glass transition temperatures. On the other hand, the relaxation frequencies of the beta processes, which are often called as the Johari-Goldstein processes, follow the Arrhenius-type temperature dependence. The relaxation parameters for the beta process are quite similar among the polyols at temperatures below the alphabeta merging temperature, T(M). However, they show anomalous behavior near T(M), which depends on the molecular size of materials. These results suggest that the origin of the beta process is essentially the same among the polyols.
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Affiliation(s)
- Ayumi Minoguchi
- Division of Physics, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
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Duvvuri K, Richert R. Dielectric hole burning in the high frequency wing of supercooled glycerol. J Chem Phys 2003. [DOI: 10.1063/1.1529193] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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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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Hempel E, Hempel G, Hensel A, Schick C, Donth E. Characteristic Length of Dynamic Glass Transition near Tg for a Wide Assortment of Glass-Forming Substances. J Phys Chem B 2000. [DOI: 10.1021/jp991153f] [Citation(s) in RCA: 315] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- E. Hempel
- Fachbereich Physik, Universität Halle, D-06099 Halle (Saale), Germany, and Fachbereich Physik, Universität Rostock, D-18051 Rostock, Germany
| | - G. Hempel
- Fachbereich Physik, Universität Halle, D-06099 Halle (Saale), Germany, and Fachbereich Physik, Universität Rostock, D-18051 Rostock, Germany
| | - A. Hensel
- Fachbereich Physik, Universität Halle, D-06099 Halle (Saale), Germany, and Fachbereich Physik, Universität Rostock, D-18051 Rostock, Germany
| | - C. Schick
- Fachbereich Physik, Universität Halle, D-06099 Halle (Saale), Germany, and Fachbereich Physik, Universität Rostock, D-18051 Rostock, Germany
| | - E. Donth
- Fachbereich Physik, Universität Halle, D-06099 Halle (Saale), Germany, and Fachbereich Physik, Universität Rostock, D-18051 Rostock, Germany
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