2D-ELDOR detection of magnetization transfer of nitroxides in disordered solid polymers

Maresch, Günter; Weber, Mark; Dubinskii, A. A.; Spiess, Hans Wolfgang

doi:10.1016/0009-2614(92)85696-8

Cited by 34 publications

(22 citation statements)

References 13 publications

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“…Quasi-librational motions are stochastic angular displacements with frequencies of 10 10 -10 12 s À1 and amplitudes up to . This type of motion in glasses has been evidenced by highfrequency ESR, 21 magnetization transfer, 22 and spinecho experiments. [23][24][25][26] The simulation of ESR spectra 15,17 has shown that amplitudes of quasi-librations increase and the distribution of quasi-libration amplitudes becomes apparent as the temperature rises within temperature range I.…”

Section: Introductionmentioning

confidence: 92%

Molecular mobility of nitroxide spin probes in glassy polymers: Models of the complex motion of spin probes

Chernova

Vorobiev

2011

J of Applied Polymer Sci

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The rotational mobility of molecules in glassy polymers was investigated by quantitative simulations of electron spin resonance spectra of nitroxide spin probes with molecules of different sizes. The motional models were determined unambiguously when the experimental and calculated spectra coincided within the level of experimental error. Temperature ranges in which different motional models were applicable were determined. Quasilibrational movements and the distribution of rotational mobility were found to be necessary for the qualitative description of spin-probe mobility in glassy polymers. The quantitative and empirical characteristics of rotational mobility were examined.

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Section: Introductionmentioning

confidence: 92%

Molecular mobility of nitroxide spin probes in glassy polymers: Models of the complex motion of spin probes

Chernova

Vorobiev

2011

J of Applied Polymer Sci

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“…A recently introduced two-dimensional electron paramagnetic resonance (EPR) technique, Field-Step Electron Double Resonance (FS ELDOR), which is an analog of 2 0 exchange NMR, can probe such dynamics in great detail. 3 The FS ELDOR experi-*To whom correspondence should be addressed. ment is the first to enable the measurement of complete two-dimensional exchange spectra of nitroxide spin probes and spin labels in disordered solids with uniform excitation over the entire spectrum and thus exclude phase distortions: which considerably limit the application of the Fourier transform ZD-ELDOR technique4 to broad powder spectra.…”

Section: Introductionmentioning

confidence: 99%

Characterization of the motion of spin probes and spin labels in amorphous polymers with two-dimensional field-step ELDOR

Saalmueller

Long

Volkmer

et al. 1996

J. Polym. Sci. B Polym. Phys.

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The motion of nitroxide spin probes and spin labels in amorphous polymers is studied below the glass transition temperature with a two‐dimensional pulsed electron double‐resonance experiment. Polystyrene and a liquid crystalline side group polymer are studied using both spin probes and spin labels covalently bound to specific sites along the polymer chain. Two methyl acrylic polymers differing only in their side group structure and polyvinylacetate are compared and large differences in the molecular dynamics deduced from both the nuclear and the electron spin relaxation rates are observed as the glass transition is approached. The results demonstrate the complexity of small amplitude motion in simple polymers below the glass transition temperature and show that it is very sensitive to the packing in the polymer. © 1996 John Wiley & Sons, Inc.

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“…It has to be noted that multidimensional NMR is restricted to probing dynamics much slower than the processes considered in the mode coupling theory [19]. By virtue of multidimensional EPR spectroscopy, [20] …”

mentioning

confidence: 99%

Rate Memory of Structural Relaxation in Glasses and Its Detection by Multidimensional NMR

et al. 1995

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A new aspect of the nature of the relaxation rate distribution of n relaxation in glasses is analyzed for the example of a polymer: How long does a polymer segment remember its relaxation rate? For a two-state system we describe the rate memory in terms of a single dimensionless parameter. Applying the theory to multidimensional NMR exchange experiments, the rate memory of a polymer slightly above its glass transition temperature is determined.The rate memory is near its theoretical minimum, indicating strong coupling of the individual relaxation modes.

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2D-ELDOR detection of magnetization transfer of nitroxides in disordered solid polymers

Cited by 34 publications

References 13 publications

Molecular mobility of nitroxide spin probes in glassy polymers: Models of the complex motion of spin probes

Molecular mobility of nitroxide spin probes in glassy polymers: Models of the complex motion of spin probes

Characterization of the motion of spin probes and spin labels in amorphous polymers with two-dimensional field-step ELDOR

Rate Memory of Structural Relaxation in Glasses and Its Detection by Multidimensional NMR

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