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Becher M, Flämig M, Rössler EA. Field-cycling 31P and 1H NMR relaxometry studying the reorientational dynamics of glass forming organophosphates. J Chem Phys 2022; 156:074502. [DOI: 10.1063/5.0082566] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- M. Becher
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - M. Flämig
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - E. A. Rössler
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
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Becher M, Körber T, Döß A, Hinze G, Gainaru C, Böhmer R, Vogel M, Rössler EA. Nuclear Spin Relaxation in Viscous Liquids: Relaxation Stretching of Single-Particle Probes. J Phys Chem B 2021; 125:13519-13532. [PMID: 34860530 DOI: 10.1021/acs.jpcb.1c06722] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Spin-lattice relaxation rates R1(ω,T), probed via high-field and field-cycling nuclear magnetic resonance (NMR), are used to test the validity of frequency-temperature superposition (FTS) for the reorientation dynamics in viscous liquids. For several liquids, FTS is found to apply so that master curves can be generated. The susceptibility spectra are highly similar to those obtained from depolarized light scattering (DLS) and reveal an excess wing. Where FTS works, two approaches are suggested to access the susceptibility: (i) a plot of deuteron R1(T) vs the spin-spin relaxation rate R2(T) and (ii) a plot of R1(T) vs an independently measured reference time τref(T). Using single-frequency scans, (i) allows one to extract the relaxation stretching as well as the NMR coupling constant. Surveying 26 data sets, we find Kohlrausch functions with exponents 0.39 < βK ≤ 0.67. Plots of the spin-spin relaxation rate R2─rescaled by the NMR coupling constant─as a function of temperature allow one to test how well site-specific NMR relaxations couple to a given reference process. Upon cooling of flexible molecule liquids, the site-specific dynamics is found to merge, suggesting that near Tg the molecules reorient essentially as a rigid entity. This presents a possible resolution for the much lower stretching parameters reported here at high temperatures that contrast with the ones that were reported to be universal in a recent DLS study close to Tg. Our analysis underlines that deuteron relaxation is a uniquely powerful tool to probe single-particle reorientation.
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Affiliation(s)
- M Becher
- Anorganische Chemie III and Nordbayerisches NMR Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - Th Körber
- Anorganische Chemie III and Nordbayerisches NMR Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - A Döß
- Department Chemie, Johannes Gutenberg-Universität, 55128 Mainz, Germany
| | - G Hinze
- Department Chemie, Johannes Gutenberg-Universität, 55128 Mainz, Germany
| | - C Gainaru
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany.,Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - R Böhmer
- Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany
| | - M Vogel
- Institut für Physik kondensierter Materie, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - E A Rössler
- Anorganische Chemie III and Nordbayerisches NMR Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
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Becher M, Wohlfromm T, Rössler EA, Vogel M. Molecular dynamics simulations vs field-cycling NMR relaxometry: Structural relaxation mechanisms in the glass-former glycerol revisited. J Chem Phys 2021; 154:124503. [PMID: 33810699 DOI: 10.1063/5.0048131] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
We combine field-cycling (FC) relaxometry and molecular dynamics (MD) simulations to study the rotational and translational dynamics associated with the glassy slowdown of glycerol. The 1H NMR spin-lattice relaxation rates R1(ω) probed in the FC measurements for different isotope-labelled compounds are computed from the MD trajectories for broad frequency and temperature ranges. We find high correspondence between experiment and simulation. Concerning the rotational motion, we observe that the aliphatic and hydroxyl groups show similar correlation times but different stretching parameters, while the overall reorientation associated with the structural relaxation remains largely isotropic. Additional analysis of the simulation results reveals that transitions between different molecular configurations are slow on the time scale of the structural relaxation at least at sufficiently high temperatures, indicating that glycerol rotates at a rigid entity, but the reorientation is slower for elongated than for compact conformers. The translational contribution to R1(ω) is well described by the force-free hard sphere model. At sufficiently low frequencies, universal square-root laws provide access to the molecular diffusion coefficients. In both experiment and simulation, the time scales of the rotational and translational motions show an unusually large separation, which is at variance with the Stokes-Einstein-Debye relation. To further explore this effect, we investigate the structure and dynamics on various length scales in the simulations. We observe that a prepeak in the static structure factor S(q), which is related to a local segregation of aliphatic and hydroxyl groups, is accompanied by a peak in the correlation times τ(q) from coherent scattering functions.
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Affiliation(s)
- M Becher
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - T Wohlfromm
- Institute of Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstraße 6, 64289 Darmstadt, Germany
| | - E A Rössler
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - M Vogel
- Institute of Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstraße 6, 64289 Darmstadt, Germany
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Ostrovskaya IK, Fatkullin NF, Körber T, Rössler EA, Lozovoi A, Mattea C, Stapf S. On the theory of deuteron NMR free induction decay of reptating polymer chains: Effect of end segment dynamics. J Chem Phys 2020; 152:184904. [PMID: 32414263 DOI: 10.1063/5.0005049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A self-consistent approximation beyond the Redfield limit and without using the Anderson-Weiss approximation for the Free Induction Decay (FID) of deuteron spins belonging to polymer chains undergoing reptation is formulated. The dynamical heterogeneity of the polymer segments created by the end segments is taken into account. Within an accuracy of slow-changing logarithmic factors, FID can be qualitatively described by a transition from an initial pseudo-Gaussian to a stretched-exponential decay at long times. With an increase in observation time, the contribution from end effects to the FID increases. In the regime of incoherent reptation, contributions to the FID from central segments yield an exponent of 1/4 for the stretched decay and contributions from end segments yield an exponent of 3/16. In the regime of coherent reptation, the central segments generate a stretching exponent of 1/2, whereas the end segments contribute with an exponent of 1/4. These predictions are shown to be in qualitative agreement with the experimental FIDs of perdeuterated poly(ethylene oxide) with molecular masses of 132 kg/mol and 862 kg/mol.
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Affiliation(s)
- I K Ostrovskaya
- Institute of Physics, Kazan Federal University, Kazan 420008, Tatarstan, Russia
| | - N F Fatkullin
- Institute of Physics, Kazan Federal University, Kazan 420008, Tatarstan, Russia
| | - T Körber
- Inorganic Chemistry III and Northern Bavarian NMR Centre, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - E A Rössler
- Inorganic Chemistry III and Northern Bavarian NMR Centre, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - A Lozovoi
- Department of Physics, CUNY-The City College of New York, New York, New York 10031, USA
| | - C Mattea
- Department of Technical Physics II/Polymer Physics, TU Ilmenau, P.O. Box 100 565, D-98684 Ilmenau, Germany
| | - S Stapf
- Department of Technical Physics II/Polymer Physics, TU Ilmenau, P.O. Box 100 565, D-98684 Ilmenau, Germany
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Affiliation(s)
- M. Flämig
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - M. Hofmann
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - N. Fatkullin
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
- Institute of Physics, Kazan Federal University, Kremlevskaya 18, 420008 Kazan, Tatarstan, Russia
| | - E. A. Rössler
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
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Flämig M, Fatkullin N, Rössler EA. The dynamics of the plastically crystalline phase of cyanoadamantane revisited by NMR line shape analysis and field-cycling relaxometry. J Chem Phys 2019; 151:224507. [PMID: 31837662 DOI: 10.1063/1.5126953] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The dynamics of cyanoadamantane (CN-ADA) in its plastically crystalline phase encompasses three processes: overall tumbling of the rigid molecule, rotation around the molecular symmetry axis, and vacancy diffusion. This makes CN-ADA a prototypical case to be studied by field-cycling as well as by conventional NMR relaxometry. Data are collected from 430 K down to about 4 K and frequencies in the range of 10 kHz-56 MHz are covered. The overall tumbling is interpreted as a cooperative jump process preceding along the orthogonal axis of the cubic lattice and exhibiting a temperature independent non-Lorentzian spectral density. Consequently, a master curve is constructed, which yields model-independent correlation times, which agree well with those reported in the literature. It can be interpolated by a Cole-Davidson function with a width parameter βCD = 0.83. The uniaxial rotation persisting in the glassy crystal (T < Tg = 170 K) is governed by a broad distribution of activation energies, g(E). In this case, the standard master curve construction applied for the overall tumbling, for example, fails, as the actually probed distribution of correlation times G(ln τ) strongly changes with temperature. We suggest a scaling method that generally applies for the case that a relaxation process is determined by a distribution of thermally activated processes. Frequency as well as temperature dependence of the relaxation rate can be used to reconstruct g(E). In addition, g(E) is extracted from the proton line-shape, which was measured down to 4 K. Vacancy diffusion governs the relaxation dispersion at highest temperatures; yet, a quantitative analysis is not possible due to instrumental limitations.
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Affiliation(s)
- M Flämig
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - N Fatkullin
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
| | - E A Rössler
- Nordbayerisches NMR-Zentrum, Universität Bayreuth, 95440 Bayreuth, Germany
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Körber T, Minikejew R, Pötzschner B, Bock D, Rössler EA. Dynamically asymmetric binary glass formers studied by dielectric and NMR spectroscopy. Eur Phys J E Soft Matter 2019; 42:143. [PMID: 31773406 DOI: 10.1140/epje/i2019-11909-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 10/16/2019] [Indexed: 06/10/2023]
Abstract
We investigate the component dynamics in asymmetric binary glass formers. Focusing on the dielectric spectra of the high-Tg components m-tricresyl phosphate and quinaldine mixed with toluene as low-Tg component, the broadend spectra cannot be described by Kohlrausch or Cole-Davidson (CD) functions. Instead, we apply a generalized CD function which allows to control the width of the susceptibility independently of its high-frequency flank. The spectra show a common broadening and failure of the frequency-temperature superposition with increasing toluene concentration. This is confirmed by stimulated echo experiments showing an increased stretching of the probed orientational correlation function. In analogy to the definition of Tg, we consider "isodynamic points". For each component, a different but linear concentration dependence of 1/Tiso is revealed, indicating different time scales. Qualitativly, we do not find significant differences for the present mixtures with Tg-contrasts of 63-89K compared to those with larger Tg-contrast ( [Formula: see text] K): Whereas the high-Tg component shows relaxation features similar to those of neat glass formers, yet, with "atypical" weak relaxation broadening, the faster low-Tg component displays pronounced dynamic heterogeneities. This is supported by scrutinizing NMR relaxation data of several mixtures investigated previously as a function of concentration. A universal evolution of the dynamics of the high-Tg as well as the low-Tg component is suggested for mixtures with high [Formula: see text]Tg .
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Affiliation(s)
- Th Körber
- Universität Bayreuth, Anorganische Chemie III and Nordbayerisches NMR-Zentrum, D-95440, Bayreuth, Germany
| | - R Minikejew
- Universität Bayreuth, Anorganische Chemie III and Nordbayerisches NMR-Zentrum, D-95440, Bayreuth, Germany
| | - B Pötzschner
- Universität Bayreuth, Anorganische Chemie III and Nordbayerisches NMR-Zentrum, D-95440, Bayreuth, Germany
| | - D Bock
- Universität Bayreuth, Anorganische Chemie III and Nordbayerisches NMR-Zentrum, D-95440, Bayreuth, Germany
| | - E A Rössler
- Universität Bayreuth, Anorganische Chemie III and Nordbayerisches NMR-Zentrum, D-95440, Bayreuth, Germany.
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Affiliation(s)
- M. Flämig
- Experimentalphysik II, Universität Bayreuth, Bayreuth, Germany
| | - M. Hofmann
- Department of Chemistry, Louisiana State University, Baton Rouge, LA, USA
| | - E. A. Rössler
- Experimentalphysik II, Universität Bayreuth, Bayreuth, Germany
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Mohamed F, Flämig M, Hofmann M, Heymann L, Willner L, Fatkullin N, Aksel N, Rössler EA. Scaling analysis of the viscoelastic response of linear polymers. J Chem Phys 2018; 149:044902. [PMID: 30068172 DOI: 10.1063/1.5038643] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Viscoelastic response in terms of the complex shear modulus G*(ω) of the linear polymers poly(ethylene-alt-propylene), poly(isoprene), and poly(butadiene) is studied for molar masses (M) from 3k up to 1000k and over a wide temperature range starting from the glass transition temperature Tg (174 K-373 K). Master curves G'(ωτα) and G″(ωτα) are constructed for the polymer-specific relaxation. Segmental relaxation occurring close to Tg is independently addressed by single spectra. Altogether, viscoelastic response is effectively studied over 14 decades in frequency. The structural relaxation time τα used for scaling is taken from dielectric spectra. We suggest a derivative method for identifying the different power-law regimes and their exponents along G″(ωτα) ∝ ωε″. The exponent ε″ = ε″(ωτα) ≡ d ln G″(ωτα)/d ln(ωτα) reveals more details compared to conventional analyses and displays high similarity among the polymers. Within a simple scaling model, the original tube-reptation model is extended to include contour length fluctuations (CLFs). The model reproduces all signatures of the quantitative theory by Likhtman and McLeish. The characteristic times and power-law exponents are rediscovered in ε″(ωτα). The high-frequency flank of the terminal relaxation closely follows the prediction for CLF (ε″ = -0.25), i.e., G″(ω) ∝ ω-0.21±0.02. At lower frequencies, a second regime with lower exponent ε″ is observed signaling the crossover to coherent reptation. Application of the full Likhtman-McLeish calculation provides a quantitative interpolation of ε″(ωτα) at frequencies below those of the Rouse regime. The derivative method also allows identifying the entanglement time τe. However, as the exponent in the Rouse regime (ωτe > 1) varies along εeRouse = 0.66 ± 0.04 (off the Rouse prediction εRouse = 0.5) and that at ωτe < 1 is similar, only a weak manifestation of the crossover at τe is found at highest M. Yet, calculating τe/τα= (M/Mo)2, we find good agreement among the polymers when discussing ε″(ωτe). The terminal relaxation time τt is directly read off from ε″(ωτα). Plotting τt/τe as a function of Z = M/Me, we find universal behavior as predicted by the TR model. The M dependence crosses over from an exponent significantly larger than 3.0 at intermediate M to an exponent approaching 3.0 at highest M in agreement with previous reports. The frequency of the minimum in G″(ωτα) scales as τmin ∝ M1.0±0.1. An M-independent frequency marks the crossover to glassy relaxation at the highest frequencies. Independent of the amplitude of G″(ω), which may be related to sample-to-sample differences, the derivative method is a versatile tool to provide a detailed phenomenological analysis of the viscoelastic response of complex liquids.
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Affiliation(s)
- F Mohamed
- Experimentalphysik II, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - M Flämig
- Experimentalphysik II, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - M Hofmann
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - L Heymann
- Technische Mechanik und Strömungsmechanik, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - L Willner
- Institute of Complex Systems, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - N Fatkullin
- Institute of Physics, Kazan Federal University, Kazan 420008, Tatarstan, Russia
| | - N Aksel
- Technische Mechanik und Strömungsmechanik, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - E A Rössler
- Experimentalphysik II, Universität Bayreuth, D-95440 Bayreuth, Germany
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Pötzschner B, Mohamed F, Bächer C, Wagner E, Lichtinger A, Bock D, Kreger K, Schmidt HW, Rössler EA. Non-polymeric asymmetric binary glass-formers. II. Secondary relaxation studied by dielectric, 2H NMR, and 31P NMR spectroscopy. J Chem Phys 2018; 146:164504. [PMID: 28456197 DOI: 10.1063/1.4980085] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We investigate the secondary (β-) relaxations of an asymmetric binary glass former consisting of a spirobichroman derivative (SBC; Tg = 356 K) as the high-Tg component and the low-Tg component tripropyl phosphate (TPP; Tg = 134 K). The main relaxations are studied in Paper I [B. Pötzschner et al., J. Chem. Phys. 146, 164503 (2017)]. A high Tg contrast of ΔTg = 222 K is put into effect in a non-polymeric system. Component-selective studies are carried out by combining results from dielectric spectroscopy (DS) for mass concentrations cTPP ≥ 60% and those from different methods of 2H and 31P NMR spectroscopy. In the case of NMR, the full concentration range (10% ≤ cTPP ≤ 100%) is covered. The neat components exhibit a β-relaxation (β1 (SBC) and β2 (TPP)). The latter is rediscovered by DS in the mixtures for all concentrations with unchanged time constants. NMR spectroscopy identifies the β-relaxations as being alike to those in neat glasses. A spatially highly restricted motion with angular displacement below ±10° encompassing all molecules is involved. In the low temperature range, where TPP shows the typical 31P NMR echo spectra of the β2-process, very similar spectral features are observed for the (deuterated) SBC component by 2H NMR, in addition to its "own" β1-process observed at high temperatures. Apparently, the small TPP molecules enslave the large SBC molecules to perform a common hindered reorientation. The temperature dependence of the spin-lattice relaxation time of both components is the same and reveals an angular displacement of the SBC molecules somewhat smaller than that of TPP, though the time constants τβ2 are the same. Furthermore, T1(T) of TPP in the temperature region of the β2-process is absolutely the same as in the mixture TPP/polystyrene investigated previously. It appears that the manifestations of the β-process introduced by one component are essentially independent of the second component. Finally, at cTPP ≤ 20% one finds indications that the β2-process starts to disintegrate. More and more TPP molecules get immobilized upon decreasing cTPP. We conclude that the β-process is a cooperative process.
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Affiliation(s)
- B Pötzschner
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - F Mohamed
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - C Bächer
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - E Wagner
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - A Lichtinger
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - D Bock
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - K Kreger
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - H-W Schmidt
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - E A Rössler
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
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Lozovoi A, Petrova L, Mattea C, Stapf S, Rössler EA, Fatkullin N. On the theory of the proton dipolar-correlation effect as a method for investigation of segmental displacement in polymer melts. J Chem Phys 2017; 147:074904. [DOI: 10.1063/1.4998184] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- A. Lozovoi
- Department Technical Physics II, Technische Universität Ilmenau, 98684 Ilmenau, Germany
- Institute of Physics, Kazan Federal University, Kazan 420008, Tatarstan, Russia
| | - L. Petrova
- Institute of Physics, Kazan Federal University, Kazan 420008, Tatarstan, Russia
| | - C. Mattea
- Department Technical Physics II, Technische Universität Ilmenau, 98684 Ilmenau, Germany
| | - S. Stapf
- Department Technical Physics II, Technische Universität Ilmenau, 98684 Ilmenau, Germany
| | - E. A. Rössler
- Department Experimentalphysik II, University of Bayreuth, 95440 Bayreuth, Germany
| | - N. Fatkullin
- Institute of Physics, Kazan Federal University, Kazan 420008, Tatarstan, Russia
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12
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Pötzschner B, Mohamed F, Bächer C, Wagner E, Lichtinger A, Minikejew R, Kreger K, Schmidt HW, Rössler EA. Non-polymeric asymmetric binary glass-formers. I. Main relaxations studied by dielectric, 2H NMR, and 31P NMR spectroscopy. J Chem Phys 2017; 146:164503. [DOI: 10.1063/1.4980084] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- B. Pötzschner
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - F. Mohamed
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - C. Bächer
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - E. Wagner
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - A. Lichtinger
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - R. Minikejew
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - K. Kreger
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - H.-W. Schmidt
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
| | - E. A. Rössler
- Experimentalphysik II, University of Bayreuth, 95447 Bayreuth, Germany and Macromolecular Chemistry I, University of Bayreuth, 95447 Bayreuth, Germany
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Kresse B, Becher M, Privalov AF, Hofmann M, Rössler EA, Vogel M, Fujara F. 1H NMR at Larmor frequencies down to 3Hz by means of Field-Cycling techniques. J Magn Reson 2017; 277:79-85. [PMID: 28258024 DOI: 10.1016/j.jmr.2017.02.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 01/30/2017] [Accepted: 02/02/2017] [Indexed: 06/06/2023]
Abstract
Field-Cycling (FC) NMR experiments were carried out at 1H Larmor frequencies down to about 3Hz. This could be achieved by fast switching a high polarizing magnetic field down to a low evolution field which is tilted with respect to the polarization field. Then, the low frequency Larmor precession of the nuclear spin magnetization about this evolution field is registered by means of FIDs in a high detection field. The crucial technical point of the experiment is the stabilization of the evolution field, which is achieved by compensating for temporal magnetic field fluctuations of all three spatial components. The paper reports on some other basic low field experiments such as the simultaneous measurement of the Larmor frequency and the spin-lattice relaxation time in such small fields as well as the irradiation of oscillating transversal magnetic field pulses at very low frequencies as a novel method for field calibration in low field FC NMR. The potential of low field FC is exemplified by the 1H relaxation dispersion of water at frequencies below about 2kHz stemming from the slow proton exchange process.
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Affiliation(s)
- B Kresse
- Institut für Festkörperphysik, TU Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany.
| | - M Becher
- Institut für Festkörperphysik, TU Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
| | - A F Privalov
- Institut für Festkörperphysik, TU Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
| | - M Hofmann
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA
| | - E A Rössler
- Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - M Vogel
- Institut für Festkörperphysik, TU Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
| | - F Fujara
- Institut für Festkörperphysik, TU Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
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14
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Hofmann M, Fatkullin N, Rössler EA. Inconsistencies in Determining the Entanglement Time of Poly(butadiene) from Rheology and Comparison to Results from Field-Cycling NMR. Macromolecules 2017. [DOI: 10.1021/acs.macromol.6b02546] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. Hofmann
- Department
of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - N. Fatkullin
- Institute
of Physics, Kazan Federal University, Kazan 420008, Tatarstan, Russia
| | - E. A. Rössler
- Experimentalphysik
II, Universität Bayreuth, D-95440 Bayreuth, Germany
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15
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Hofmann M, Kresse B, Heymann L, Privalov AF, Willner L, Fatkullin N, Aksel N, Fujara F, Rössler EA. Dynamics of a Paradigmatic Linear Polymer: A Proton Field-Cycling NMR Relaxometry Study on Poly(ethylene–propylene). Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b01906] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M. Hofmann
- Experimentalphysik
II, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - B. Kresse
- Institut
für Festkörperphysik, TU Darmstadt, D-64289 Darmstadt, Germany
| | - L. Heymann
- Technische
Mechanik und Strömungsmechanik, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - A. F. Privalov
- Institut
für Festkörperphysik, TU Darmstadt, D-64289 Darmstadt, Germany
| | - L. Willner
- Institute
of Complex Systems, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - N. Fatkullin
- Institute
of Physics, Kazan Federal University, Kazan 420008, Tatarstan Russia
| | - N. Aksel
- Technische
Mechanik und Strömungsmechanik, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - F. Fujara
- Institut
für Festkörperphysik, TU Darmstadt, D-64289 Darmstadt, Germany
| | - E. A. Rössler
- Experimentalphysik
II, Universität Bayreuth, D-95440 Bayreuth, Germany
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16
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Hofmann M, Kresse B, Privalov AF, Heymann L, Willner L, Aksel N, Fatkullin N, Fujara F, Rössler EA. Segmental Mean Square Displacement: Field-Cycling 1H Relaxometry vs Neutron Scattering. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b01860] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- M. Hofmann
- Experimentalphysik
II, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - B. Kresse
- Institut
für Festkörperphysik, TU Darmstadt, Hochschulstrasse 6, D-64289 Darmstadt, Germany
| | - A. F. Privalov
- Institut
für Festkörperphysik, TU Darmstadt, Hochschulstrasse 6, D-64289 Darmstadt, Germany
| | - L. Heymann
- Technische
Mechanik und Strömungsmechanik, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - L. Willner
- Institute
of Complex Systems, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - N. Aksel
- Technische
Mechanik und Strömungsmechanik, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - N. Fatkullin
- Institute
of Physics, Kazan Federal University, Kazan 420008, Tatarstan Russia
| | - F. Fujara
- Institut
für Festkörperphysik, TU Darmstadt, Hochschulstrasse 6, D-64289 Darmstadt, Germany
| | - E. A. Rössler
- Experimentalphysik
II, Universität Bayreuth, D-95440 Bayreuth, Germany
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17
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Flämig M, Becher M, Hofmann M, Körber T, Kresse B, Privalov AF, Willner L, Kruk D, Fujara F, Rössler EA. Perspectives of Deuteron Field-Cycling NMR Relaxometry for Probing Molecular Dynamics in Soft Matter. J Phys Chem B 2016; 120:7754-66. [DOI: 10.1021/acs.jpcb.6b05109] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. Flämig
- Experimentalphysik
II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - M. Becher
- Institut
für Festkörperphysik, TU Darmstadt, Hochschulstrasse 6, 64289 Darmstadt, Germany
| | - M. Hofmann
- Experimentalphysik
II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - T. Körber
- Experimentalphysik
II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - B. Kresse
- Institut
für Festkörperphysik, TU Darmstadt, Hochschulstrasse 6, 64289 Darmstadt, Germany
| | - A. F. Privalov
- Institut
für Festkörperphysik, TU Darmstadt, Hochschulstrasse 6, 64289 Darmstadt, Germany
| | - L. Willner
- Institute
of Complex Systems, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - D. Kruk
- Faculty of Mathematics and Computer Science, University of Warmia & Mazury, Słoneczna 54, 10-710 Olsztyn, Poland
| | - F. Fujara
- Institut
für Festkörperphysik, TU Darmstadt, Hochschulstrasse 6, 64289 Darmstadt, Germany
| | - E. A. Rössler
- Experimentalphysik
II, Universität Bayreuth, 95440 Bayreuth, Germany
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18
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Lozovoi A, Mattea C, Herrmann A, Rössler EA, Stapf S, Fatkullin N. Communication: Proton NMR dipolar-correlation effect as a method for investigating segmental diffusion in polymer melts. J Chem Phys 2016; 144:241101. [PMID: 27369489 DOI: 10.1063/1.4954664] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- A. Lozovoi
- Department of Technical Physics II, Technische Universität Ilmenau, 98684 Ilmenau, Germany
| | - C. Mattea
- Department of Technical Physics II, Technische Universität Ilmenau, 98684 Ilmenau, Germany
| | - A. Herrmann
- Department of Experimentalphysik II, University of Bayreuth, 95440 Bayreuth, Germany
| | - E. A. Rössler
- Department of Experimentalphysik II, University of Bayreuth, 95440 Bayreuth, Germany
| | - S. Stapf
- Department of Technical Physics II, Technische Universität Ilmenau, 98684 Ilmenau, Germany
| | - N. Fatkullin
- Institute of Physics, Kazan Federal University, Kazan, 420008 Tatarstan, Russia
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19
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Pötzschner B, Mohamed F, Lichtinger A, Bock D, Rössler EA. Dynamics of asymmetric non-polymeric binary glass formers—A nuclear magnetic resonance and dielectric spectroscopy study. J Chem Phys 2015; 143:154506. [DOI: 10.1063/1.4932981] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- B. Pötzschner
- Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - F. Mohamed
- Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - A. Lichtinger
- Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - D. Bock
- Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - E. A. Rössler
- Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
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20
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Hofmann M, Gainaru C, Cetinkaya B, Valiullin R, Fatkullin N, Rössler EA. Field-Cycling Relaxometry as a Molecular Rheology Technique: Common Analysis of NMR, Shear Modulus and Dielectric Loss Data of Polymers vs Dendrimers. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b01805] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M. Hofmann
- Experimentalphysik
II, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - C. Gainaru
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - B. Cetinkaya
- Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
| | - R. Valiullin
- Faculty of Physics and Earth
Sciences, Leipzig University, D-04103 Leipzig, Germany
| | - N. Fatkullin
- Institute of Physics, Kazan Federal University, Kazan 420008, Tatarstan, Russia
| | - E. A. Rössler
- Experimentalphysik
II, Universität Bayreuth, D-95440 Bayreuth, Germany
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21
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Kresse B, Hofmann M, Privalov AF, Fatkullin N, Fujara F, Rössler EA. All Polymer Diffusion Regimes Covered by Combining Field-Cycling and Field-Gradient 1H NMR. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b00855] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- B. Kresse
- Institut
für Festkörperphysik, TU Darmstadt, Hochschulstr. 6, D-64289 Darmstadt, Germany
| | - M. Hofmann
- Experimentalphysik
II, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - A. F. Privalov
- Institut
für Festkörperphysik, TU Darmstadt, Hochschulstr. 6, D-64289 Darmstadt, Germany
| | - N. Fatkullin
- Institute
of Physics, Kazan Federal University, Kazan 420008 Tatarstan, Russia
| | - F. Fujara
- Institut
für Festkörperphysik, TU Darmstadt, Hochschulstr. 6, D-64289 Darmstadt, Germany
| | - E. A. Rössler
- Experimentalphysik
II, Universität Bayreuth, D-95440 Bayreuth, Germany
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22
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Mohamed F, Hofmann M, Pötzschner B, Fatkullin N, Rössler EA. Dynamics of PPI Dendrimers: A Study by Dielectric and 2H NMR Spectroscopy and by Field-Cycling 1H NMR Relaxometry. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b00486] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- F. Mohamed
- Experimentalphysik
II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - M. Hofmann
- Experimentalphysik
II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - B. Pötzschner
- Experimentalphysik
II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - N. Fatkullin
- Institute
of Physics, Kazan Federal University, Kazan 420008, Tatarstan Russia
| | - E. A. Rössler
- Experimentalphysik
II, Universität Bayreuth, 95440 Bayreuth, Germany
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23
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Affiliation(s)
- B. Schmidtke
- Experimentalphysik II, Universität Bayreuth, D-95444 Bayreuth, Germany
| | - M. Hofmann
- Experimentalphysik II, Universität Bayreuth, D-95444 Bayreuth, Germany
| | - A. Lichtinger
- Experimentalphysik II, Universität Bayreuth, D-95444 Bayreuth, Germany
| | - E. A. Rössler
- Experimentalphysik II, Universität Bayreuth, D-95444 Bayreuth, Germany
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24
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Meier R, Schneider E, Rössler EA. Change of translational-rotational coupling in liquids revealed by field-cycling 1H NMR. J Chem Phys 2015; 142:034503. [DOI: 10.1063/1.4904719] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Affiliation(s)
- R. Meier
- Experimentalphysik II, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - E. Schneider
- Experimentalphysik II, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - E. A. Rössler
- Experimentalphysik II, Universität Bayreuth, D-95440 Bayreuth, Germany
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25
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Hofmann M, Kresse B, Privalov AF, Willner L, Fatkullin N, Fujara F, Rössler EA. Field-Cycling NMR Relaxometry Probing the Microscopic Dynamics in Polymer Melts. Macromolecules 2014. [DOI: 10.1021/ma501520u] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- M. Hofmann
- Experimentalphysik
II, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - B. Kresse
- Institut für Festkörperphysik, TU Darmstadt, Hochschulstrasse 6, D-64289 Darmstadt, Germany
| | - A. F. Privalov
- Institut für Festkörperphysik, TU Darmstadt, Hochschulstrasse 6, D-64289 Darmstadt, Germany
| | - L. Willner
- Institute of Complex
Systems, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - N. Fatkullin
- Institute of Physics, Kazan Federal University, Kazan 420008, Tatarstan Russia
| | - F. Fujara
- Institut für Festkörperphysik, TU Darmstadt, Hochschulstrasse 6, D-64289 Darmstadt, Germany
| | - E. A. Rössler
- Experimentalphysik
II, Universität Bayreuth, D-95440 Bayreuth, Germany
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26
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Schmidtke B, Rössler EA. Depolarized light scattering spectra of molecular liquids: Described in terms of mode coupling theory. J Chem Phys 2014; 141:044511. [PMID: 25084930 DOI: 10.1063/1.4890731] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Depolarized light scattering spectra of eight molecular liquids as obtained from applying tandem-Fabry-Pérot interferometry and double monochromator are analyzed in the frame work of the mode coupling theory (MCT). The susceptibility spectra are fitted to the numerical solution of the schematic F12 model of MCT and the validity of the asymptotic laws is discussed. The model is able to quantitatively describe the spectra up to the boiling point, where the main (structural) relaxation and the contribution of the microscopic (vibrational) dynamics essentially merge, and down to the moderately super-cooled liquid where glassy dynamics establishes. The changes of the spectra with temperature are mapped to only two control parameters, which show a smooth variation with temperature. Strong correlation between experimental stretching parameters and extrapolated values from the model is found. The numerical solutions are extrapolated down to Tc, where the asymptotic scaling laws can be applied. Although the spectra apparently follow scaling relations, the application of the asymptotic laws usually overestimates Tc by up to 12 K. In all the cases, the experimental spectra are outside the applicability regime of the asymptotic laws. This is explained by more or less strong vibrational contributions. Within a phenomenological approach which extends the spectral analysis down to Tg and which allows for separating fast and slow dynamics, the strength of the fast dynamics 1 - frel is revealed. It shows the cusp-like anomaly predicted by MCT; yet, the corresponding critical temperature is significantly higher than that derived from the F12 model. In addition, we demonstrate that close to Tg, the susceptibility minimum is controlled by the interplay of the excess wing and the fast dynamics contribution.
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Affiliation(s)
- B Schmidtke
- Experimentalphysik II, Universität Bayreuth, D-95444 Bayreuth, Germany
| | - E A Rössler
- Experimentalphysik II, Universität Bayreuth, D-95444 Bayreuth, Germany
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27
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Kruk D, Meier R, Rachocki A, Korpała A, Singh RK, Rössler EA. Determining diffusion coefficients of ionic liquids by means of field cycling nuclear magnetic resonance relaxometry. J Chem Phys 2014; 140:244509. [DOI: 10.1063/1.4882064] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- D. Kruk
- Faculty of Mathematics and Computer Science, University of Warmia and Mazury in Olsztyn, Słoneczna 54, PL-10710 Olsztyn, Poland
- Universität Bayreuth, Experimentalphysik II, 95440 Bayreuth, Germany
| | - R. Meier
- Universität Bayreuth, Experimentalphysik II, 95440 Bayreuth, Germany
| | - A. Rachocki
- Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznań, Poland
| | - A. Korpała
- Department of Biophysics, Jagiellonian University Medical College, Łazarza 16, 31-530 Kraków, Poland and Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Kraków, Poland
| | - R. K. Singh
- Ionic Liquid and Solid State Ionics Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221 005, India
| | - E. A. Rössler
- Universität Bayreuth, Experimentalphysik II, 95440 Bayreuth, Germany
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28
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Schmidtke B, Petzold N, Pötzschner B, Weingärtner H, Rössler EA. Relaxation Stretching, Fast Dynamics, and Activation Energy: A Comparison of Molecular and Ionic Liquids as Revealed by Depolarized Light Scattering. J Phys Chem B 2014; 118:7108-18. [DOI: 10.1021/jp412297u] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- B. Schmidtke
- Experimentalphysik
II, Universität Bayreuth, D-95444 Bayreuth, Germany
| | - N. Petzold
- Experimentalphysik
II, Universität Bayreuth, D-95444 Bayreuth, Germany
| | - B. Pötzschner
- Experimentalphysik
II, Universität Bayreuth, D-95444 Bayreuth, Germany
| | - H. Weingärtner
- Physikalische
Chemie II, Ruhr-Universität Bochum, D-44780 Bochum, Germany
| | - E. A. Rössler
- Experimentalphysik
II, Universität Bayreuth, D-95444 Bayreuth, Germany
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29
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Kruk D, Korpała A, Taheri SM, Kozłowski A, Förster S, Rössler EA. 1H relaxation enhancement induced by nanoparticles in solutions: Influence of magnetic properties and diffusion. J Chem Phys 2014; 140:174504. [DOI: 10.1063/1.4871461] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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30
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Kresse B, Privalov AF, Herrmann A, Hofmann M, Rössler EA, Fujara F. Simultaneous measurement of very small magnetic fields and spin-lattice relaxation. Solid State Nucl Magn Reson 2014; 59-60:45-47. [PMID: 24704307 DOI: 10.1016/j.ssnmr.2014.03.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 03/07/2014] [Accepted: 03/07/2014] [Indexed: 06/03/2023]
Abstract
A field cycling (FC) NMR experiment is presented which allows for the simultaneous determination of very small magnetic fields down to about 3 μT and the concomitant measurement of nuclear spin-lattice relaxation times in these fields. The technique will enable broadband spin-lattice relaxation dispersion experiments down to about 100 Hz (1)H Larmor frequency. Limitations of its applicability are discussed.
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Affiliation(s)
- B Kresse
- Institut für Festkörperphysik, TU Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany.
| | - A F Privalov
- Institut für Festkörperphysik, TU Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
| | - A Herrmann
- Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - M Hofmann
- Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - E A Rössler
- Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - F Fujara
- Institut für Festkörperphysik, TU Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
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31
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Bock D, Kahlau R, Pötzschner B, Körber T, Wagner E, Rössler EA. Dynamics of asymmetric binary glass formers. II. Results from nuclear magnetic resonance spectroscopy. J Chem Phys 2014; 140:094505. [DOI: 10.1063/1.4865945] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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32
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Kahlau R, Bock D, Schmidtke B, Rössler EA. Dynamics of asymmetric binary glass formers. I. A dielectric and nuclear magnetic resonance spectroscopy study. J Chem Phys 2014; 140:044509. [DOI: 10.1063/1.4861428] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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33
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Kruk D, Hoffmann SK, Goslar J, Lijewski S, Kubica-Misztal A, Korpała A, Oglodek I, Kowalewski J, Rössler EA, Moscicki J. ESR lineshape and 1H spin-lattice relaxation dispersion in propylene glycol solutions of nitroxide radicals--joint analysis. J Chem Phys 2013; 139:244502. [PMID: 24387377 DOI: 10.1063/1.4850635] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Electron Spin Resonance (ESR) spectroscopy and Nuclear Magnetic Relaxation Dispersion (NMRD) experiments are reported for propylene glycol solutions of the nitroxide radical: 4-oxo-TEMPO-d16 containing (15)N and (14)N isotopes. The NMRD experiments refer to (1)H spin-lattice relaxation measurements in a broad frequency range (10 kHz-20 MHz). A joint analysis of the ESR and NMRD data is performed. The ESR lineshapes give access to the nitrogen hyperfine tensor components and the rotational correlation time of the paramagnetic molecule. The NMRD data are interpreted in terms of the theory of paramagnetic relaxation enhancement in solutions of nitroxide radicals, recently presented by Kruk et al. [J. Chem. Phys. 138, 124506 (2013)]. The theory includes the effect of the electron spin relaxation on the (1)H relaxation of the solvent. The (1)H relaxation is caused by dipole-dipole interactions between the electron spin of the radical and the proton spins of the solvent molecules. These interactions are modulated by three dynamic processes: relative translational dynamics of the involved molecules, molecular rotation, and electron spin relaxation. The sensitivity to rotation originates from the non-central positions of the interacting spin in the molecules. The electronic relaxation is assumed to stem from the electron spin-nitrogen spin hyperfine coupling, modulated by rotation of the radical molecule. For the interpretation of the NMRD data, we use the nitrogen hyperfine coupling tensor obtained from ESR and fit the other relevant parameters. The consistency of the unified analysis of ESR and NMRD, evaluated by the agreement between the rotational correlation times obtained from ESR and NMRD, respectively, and the agreement of the translation diffusion coefficients with literature values obtained for pure propylene glycol, is demonstrated to be satisfactory.
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Affiliation(s)
- D Kruk
- University of Warmia & Mazury in Olsztyn, Faculty of Mathematics & Computer Science, Sloneczna 54, PL-10710 Olsztyn, Poland
| | - S K Hoffmann
- Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznan, Poland
| | - J Goslar
- Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznan, Poland
| | - S Lijewski
- Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznan, Poland
| | - A Kubica-Misztal
- Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Krakow, Poland
| | - A Korpała
- Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Krakow, Poland
| | - I Oglodek
- Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Krakow, Poland
| | - J Kowalewski
- Arrhenius Laboratory, Department of Materials and Environmental Chemistry, Stockholm University, S-106 91 Stockholm, Sweden
| | - E A Rössler
- Universität Bayreuth, Experimentalphysik II, 95440 Bayreuth, Germany
| | - J Moscicki
- Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Krakow, Poland
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34
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Micko B, Tschirwitz C, Rössler EA. Secondary relaxation processes in binary glass formers: emergence of "islands of rigidity". J Chem Phys 2013; 138:154501. [PMID: 23614424 DOI: 10.1063/1.4798655] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
In addition to the primary α-process, some neat glass formers show a well resolved secondary β-process (type-B) or solely an excess wing (type-A). We investigate two binary glass forming systems composed of a type-A and a type-B component. (2)H nuclear magnetic resonance (NMR) spectroscopy is selectively applied to the type-B component in order to characterize the β-process over a large range of mole fractions x in the glassy state. We demonstrate that for x ≳ 0.75 the apparent relaxation strength is constant, i.e., all molecules of type-B participate in the β-process and the time constant τβ(T) is independent of concentration. For x < 0.75, however, the apparent relaxation strength decreases abruptly, which we interpret in terms of population: below this concentration a fraction ξ of type-B molecules still exhibits essentially the β-process of the neat system (in terms of time scale and mechanism), while others have been immobilized. The arise of such a scenario is verified by 2D and spin-lattice relaxation (2)H NMR techniques. In selective (2)H NMR experiments on the type-A component we observe a contribution to the β-process of the type-B molecules at medium concentrations. The latter finding and the rather sharp threshold occurring at x ≈ 0.75 may indicate that the β-process is a cooperative process.
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Affiliation(s)
- B Micko
- Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
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35
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Kahlau R, Dörfler T, Rössler EA. Secondary relaxations in a series of organic phosphate glasses revealed by dielectric spectroscopy. J Chem Phys 2013; 139:134504. [DOI: 10.1063/1.4822002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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36
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Schmidtke B, Petzold N, Kahlau R, Rössler EA. Reorientational dynamics in molecular liquids as revealed by dynamic light scattering: From boiling point to glass transition temperature. J Chem Phys 2013; 139:084504. [DOI: 10.1063/1.4817406] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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37
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Bock D, Kahlau R, Micko B, Pötzschner B, Schneider GJ, Rössler EA. On the cooperative nature of the β-process in neat and binary glasses: a dielectric and nuclear magnetic resonance spectroscopy study. J Chem Phys 2013; 139:064508. [PMID: 23947872 DOI: 10.1063/1.4816374] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
By means of dielectric as well as (2)H and (31)P nuclear magnetic resonance spectroscopy (NMR) the component dynamics of the binary glass tripropyl phosphate (TPP)/polystyrene (PS/PS-d3) is selectively investigated for concentrations distributed over the full range. We study the secondary (β-) relaxation below T(g), which is found in all investigated samples containing TPP, but not in neat polystyrene. The dielectric spectrum of the β-process is described by an asymmetric distribution of activation energies, essentially not changing in the entire concentration regime; its most probable value is E/k ≅ 24 T(g). Persistence of the β-process is confirmed by (31)P NMR Hahn-echo and spin-lattice relaxation experiments on TPP, which identify the nature of the β-process as being highly spatially hindered as found for other (neat) glasses studied previously, or re-investigated within this work. The corresponding (2)H NMR experiments on PS-d3 confirm the absence of a β-process in neat PS-d3, but reveal a clear signature of a β-process in the mixture, i.e., polystyrene monomers perform essentially the same type of secondary relaxation as the TPP molecules. Yet, there are indications that some fractions of PS-d3 as well as TPP molecules become immobilized in the mixture in contrast to the case of neat glasses. We conclude that in a binary glass the β-process introduced by one component induces a highly similar motion in the second component, and this may be taken as an indication of its cooperative nature.
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Affiliation(s)
- D Bock
- Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
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38
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Meier R, Herrmann A, Hofmann M, Schmidtke B, Kresse B, Privalov AF, Kruk D, Fujara F, Rössler EA. Iso-Frictional Mass Dependence of Diffusion of Polymer Melts Revealed by 1H NMR Relaxometry. Macromolecules 2013. [DOI: 10.1021/ma400881c] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- R. Meier
- Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - A. Herrmann
- Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - M. Hofmann
- Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - B. Schmidtke
- Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - B. Kresse
- Institut für Festkörperphysik, TU Darmstadt, Hochschulstrasse 6, 64289 Darmstadt,
Germany
| | - A. F. Privalov
- Institut für Festkörperphysik, TU Darmstadt, Hochschulstrasse 6, 64289 Darmstadt,
Germany
| | - D. Kruk
- Faculty of Mathematics & Computer Science, University of Warmia & Mazury in Olsztyn, 10710 Olsztyn, Poland
| | - F. Fujara
- Institut für Festkörperphysik, TU Darmstadt, Hochschulstrasse 6, 64289 Darmstadt,
Germany
| | - E. A. Rössler
- Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
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39
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Petzold N, Schmidtke B, Kahlau R, Bock D, Meier R, Micko B, Kruk D, Rössler EA. Evolution of the dynamic susceptibility in molecular glass formers: Results from light scattering, dielectric spectroscopy, and NMR. J Chem Phys 2013; 138:12A510. [DOI: 10.1063/1.4770055] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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40
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Kruk D, Korpała A, Kubica A, Kowalewski J, Rössler EA, Moscicki J. 1H relaxation dispersion in solutions of nitroxide radicals: Influence of electron spin relaxation. J Chem Phys 2013; 138:124506. [DOI: 10.1063/1.4795006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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41
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Micko B, Kruk D, Rössler EA. Primary and secondary relaxation process in plastically crystalline cyanocyclohexane studied by 2H nuclear magnetic resonance. II. Quantitative analysis. J Chem Phys 2013; 138:074504. [DOI: 10.1063/1.4790398] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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42
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Micko B, Lusceac SA, Zimmermann H, Rössler EA. Primary and secondary relaxation process in plastically crystalline cyanocyclohexane studied by 2H nuclear magnetic resonance. I. J Chem Phys 2013; 138:074503. [PMID: 23445020 DOI: 10.1063/1.4790397] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We study the main (α-) and secondary (β-) relaxation in the plastically crystalline (PC) phase of cyanocyclohexane by various 2H nuclear magnetic resonance (NMR) methods (line-shape, spin-lattice relaxation, stimulated echo, and two-dimensional spectra) above and below the glass transition temperature T(g) = 134 K. Our results regarding the α-process demonstrate that molecular motion is not governed by the symmetry of the lattice. Rather it is similar to the one reported for structural glass formers and can be modeled by a reorientation proceeding via a distribution of small and large angular jumps. A solid-echo line-shape analysis regarding the β-process below T(g) yields again very similar results when compared to those of the structural glass formers ethanol and toluene. Hence we cannot confirm an intramolecular origin for the β-process in cyanocyclohexane. The fast β-process in the PC phase allows for the first time a detailed 2H NMR study of the process also at T > T(g): an additional minimum in the spin-lattice relaxation time reflecting the β-process is found. Furthermore the solid-echo spectra show a distinct deviation from the rigid limit Pake pattern, which allows a direct determination of the temperature dependent spatial restriction of the process. In Part II of this work, a quantitative analysis is carried out, where we demonstrate that within the model of a "wobbling in a cone" the mean cone angle increases above T(g) and the corresponding relaxation strength is compared to dielectric results.
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Affiliation(s)
- B Micko
- Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
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43
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Meier R, Herrmann A, Kresse B, Privalov AF, Kruk D, Fujara F, Rössler EA. Long-Time Diffusion in Polymer Melts Revealed by 1H NMR Relaxometry. ACS Macro Lett 2013; 2:96-99. [PMID: 35581766 DOI: 10.1021/mz300571t] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We demonstrate that field-cycling 1H NMR relaxometry can be used as a straightforward method of determining translational diffusion coefficient D = D(M) in polymer systems. The 1H spin-lattice relaxation dispersion for polybutadiene of different molecular masses M (446 < M/(g mol-1) < 9470) is measured at several temperatures (233 < T/K < 408) in a broad frequency range. The diffusion coefficient D(T) is determined from the intermolecular contribution to the overall spin-lattice relaxation rate R1(ω), which dominates in the low-frequency range and follows a universal dispersion law linear in √ω. The extracted diffusion coefficients are in good agreement with the values obtained previously by field gradient NMR. The molecular mass dependence D = D(M) exhibits two power laws: D ∝ M-1.3±0.1 and ∝M-2.3±0.1. They show a crossover for M = 2300, a value that is close to the entanglement molecular mass Me of polybutadiene. The corresponding power-law exponents are close to the prediction of the tube-reptation model.
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Affiliation(s)
- R. Meier
- Experimentalphysik
II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - A. Herrmann
- Experimentalphysik
II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - B. Kresse
- Institut für
Festkörperphysik, Technische Universität Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
| | - A. F. Privalov
- Institut für
Festkörperphysik, Technische Universität Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
| | - D. Kruk
- University of Warmia and Mazury in Olsztyn,Faculty of Mathematics
and Computer Science, Sloneczna 54, PL-10710 Olsztyn,
Poland
| | - F. Fujara
- Institut für
Festkörperphysik, Technische Universität Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany
| | - E. A. Rössler
- Experimentalphysik
II, Universität Bayreuth, 95440 Bayreuth, Germany
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44
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Kruk D, Korpała A, Kubica A, Meier R, Rössler EA, Moscicki J. Translational diffusion in paramagnetic liquids by 1H NMR relaxometry: nitroxide radicals in solution. J Chem Phys 2013; 138:024506. [PMID: 23320703 DOI: 10.1063/1.4772097] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
For nitroxide radicals in solution one can identify three frequency regimes in which (1)H spin-lattice relaxation rate of solvent molecules depend linearly on square root of the (1)H resonance frequency. Combining a recently developed theory of nuclear (proton) spin-lattice relaxation in solutions of nitroxide radicals [D. Kruk et al., J. Chem. Phys. 137, 044512 (2012)] with properties of the spectral density function associated with translational dynamics, relationships between the corresponding linear changes of the relaxation rate (for (14)N spin probes) and relative translational diffusion coefficient of the solvent and solute molecules have been derived (in analogy to (15)N spin probes [E. Belorizky et al., J. Phys. Chem. A 102, 3674 (1998)]). This method allows a simple and straightforward determination of diffusion coefficients in spin-labeled systems, by means of (1)H nuclear magnetic resonance (NMR) relaxometry. The approach has thoroughly been tested by applying to a large set of experimental data-(1)H spin-lattice relaxation dispersion results for solutions of different viscosity (decalin, glycerol, propylene glycol) of (14)N and (15)N spin probes. The experiments have been performed versus temperature (to cover a broad range of translational diffusion coefficients) using field cycling spectrometer which covers three decades in (1)H resonance frequency, 10 kHz-20 MHz. The limitations of NMR relaxometry caused by the time scale of the translational dynamics as well as electron spin relaxation have been discussed. It has been shown that for spin-labeled systems NMR relaxometry gives access to considerably faster diffusion processes than for diamagnetic systems.
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Affiliation(s)
- D Kruk
- Faculty of Mathematics and Computer Science, University of Warmia and Mazury in Olsztyn, Sloneczna 54, PL-10710 Olsztyn, Poland.
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45
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Schmidtke B, Petzold N, Kahlau R, Hofmann M, Rössler EA. From boiling point to glass transition temperature: transport coefficients in molecular liquids follow three-parameter scaling. Phys Rev E Stat Nonlin Soft Matter Phys 2012; 86:041507. [PMID: 23214591 DOI: 10.1103/physreve.86.041507] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 08/03/2012] [Indexed: 06/01/2023]
Abstract
The phenomenon of the glass transition is an unresolved problem in condensed matter physics. Its prominent feature, the super-Arrhenius temperature dependence of the transport coefficients, remains a challenge to be described over the full temperature range. For a series of molecular glass formers, we combined τ(T) collected from dielectric spectroscopy and dynamic light scattering covering a range 10(-12) s < τ(T) < 10(2) s. Describing the dynamics in terms of an activation energy E(T), we distinguish a high-temperature regime characterized by an Arrhenius law with a constant activation energy E(∞) and a low-temperature regime for which E(coop)(T) ≡ E(T)-E(∞) increases exponentially while cooling. A scaling is introduced, specifically E(coop)(T)/E(∞) [proportionality] exp[-λ(T/T(A)-1)], where λ is a fragility parameter and T(A) a reference temperature proportional to E(∞). In order to describe τ(T) still the attempt time τ(∞) has to be specified. Thus, a single interaction parameter E(∞) describing the high-temperature regime together with λ controls the temperature dependence of low-temperature cooperative dynamics.
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Affiliation(s)
- B Schmidtke
- Universität Bayreuth, Experimentalphysik II, D-95440 Bayreuth, Germany
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46
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Herrmann A, Kresse B, Wohlfahrt M, Bauer I, Privalov AF, Kruk D, Fatkullin N, Fujara F, Rössler EA. Mean Square Displacement and Reorientational Correlation Function in Entangled Polymer Melts Revealed by Field Cycling 1H and 2H NMR Relaxometry. Macromolecules 2012. [DOI: 10.1021/ma301099h] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- A. Herrmann
- Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - B. Kresse
- Institut für Festkörperphysik, TU Darmstadt, Hochschulstrasse 6, 64289 Darmstadt,
Germany
| | - M. Wohlfahrt
- Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - I. Bauer
- Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - A. F. Privalov
- Institut für Festkörperphysik, TU Darmstadt, Hochschulstrasse 6, 64289 Darmstadt,
Germany
| | - D. Kruk
- Faculty of Mathematics & Computer Science, University of Warmia & Mazury Olsztyn, Sloneczna 54, 10710 Olsztyn, Poland
| | - N. Fatkullin
- Institute of Physics, Kazan Federal University, Kazan 420008, Tatarstan, Russia
| | - F. Fujara
- Institut für Festkörperphysik, TU Darmstadt, Hochschulstrasse 6, 64289 Darmstadt,
Germany
| | - E. A. Rössler
- Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany
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47
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Kruk D, Korpała A, Kowalewski J, Rössler EA, Moscicki J. 1H relaxation dispersion in solutions of nitroxide radicals: Effects of hyperfine interactions with 14N and 15N nuclei. J Chem Phys 2012; 137:044512. [DOI: 10.1063/1.4736854] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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48
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Kruk D, Herrmann A, Rössler EA. Field-cycling NMR relaxometry of viscous liquids and polymers. Prog Nucl Magn Reson Spectrosc 2012; 63:33-64. [PMID: 22546344 DOI: 10.1016/j.pnmrs.2011.08.001] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 08/17/2011] [Indexed: 05/27/2023]
Affiliation(s)
- D Kruk
- Universität Bayreuth, Experimentalphysik II, 95440 Bayreuth, Germany
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49
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Hofmann M, Herrmann A, Abou Elfadl A, Kruk D, Wohlfahrt M, Rössler EA. Glassy, Rouse, and Entanglement Dynamics As Revealed by Field Cycling 1H NMR Relaxometry. Macromolecules 2012. [DOI: 10.1021/ma202371p] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- M. Hofmann
- Experimentalphysik
II, Universität Bayreuth, D-95440
Bayreuth, Germany
| | - A. Herrmann
- Experimentalphysik
II, Universität Bayreuth, D-95440
Bayreuth, Germany
| | - A. Abou Elfadl
- Experimentalphysik
II, Universität Bayreuth, D-95440
Bayreuth, Germany
| | - D. Kruk
- University of Warmia & Mazury Olsztyn, Faculty of Mathematics & Computer Science, Sloneczna 54, PL-10710 Olsztyn, Poland
| | - M. Wohlfahrt
- Experimentalphysik
II, Universität Bayreuth, D-95440
Bayreuth, Germany
| | - E. A. Rössler
- Experimentalphysik
II, Universität Bayreuth, D-95440
Bayreuth, Germany
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50
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Kruk D, Meier R, Rössler EA. Nuclear magnetic resonance relaxometry as a method of measuring translational diffusion coefficients in liquids. Phys Rev E Stat Nonlin Soft Matter Phys 2012; 85:020201. [PMID: 22463139 DOI: 10.1103/physreve.85.020201] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Indexed: 05/31/2023]
Abstract
By application of the field-cycling technique, we measure the dispersion of the (1)H nuclear magnetic resonance (NMR) spin-lattice relaxation time T(1)(ω) for a series of molecular liquids. We demonstrate that such NMR relaxometry studies can be used for determining diffusion coefficients. A broad frequency range of 10 kHz-20 MHz is covered. By scanning T(1)(ω) one directly probes the spectral density of the diffusion processes. The value of the diffusion coefficient D can be determined from a linear dependence of the (1)H spin-lattice relaxation rate on the square root of the frequency at which it is measured. The power of this method lies in its simplicity, which allows one to determine D(T) independently of the diffusive model. The results obtained are in very good agreement with those of field gradient NMR methods.
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Affiliation(s)
- D Kruk
- Experimentalphysik II, Universität Bayreuth, D-95440 Bayreuth, Germany
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