NMR studies of synthetic polymers and biomacromolecules, which provide insight into the conformation and dynamics of these materials, can benefit strongly from the increased sensitivity offered by dynamic nuclear polarization (DNP) and other hyperpolarizing methods. In this study (1) H DNP nuclear spin hyperpolarization of two polybutadiene samples, representing a supercooled liquid and an entangled polymer melt, is demonstrated at 0.35 T magnetic field strength and at temperatures between -80 and +50 degrees C. Electron spin polarization transfer from the alpha,gamma-bisdiphenylene-beta-phenylallyl radical to the sample nuclei is achieved by the Overhauser and solid effect. DNP signal enhancements are studied, varying the electron spin resonance offset, microwave power, and sample temperature. The influence of spin relaxation times, line widths, and molecular dynamics are discussed. The results show promising, up to 15-fold NMR signal enhancements using noncryogenic temperatures and an inexpensive setup that is less technically demanding than current high-field DNP setups.
Electron Spin–Lattice Relaxation Mechanisms of Nitroxyl Radicals in Ionic Liquids and Conventional Organic Liquids: Temperature Dependence of a Thermally Activated Process
From The DNP-NMR Blog:
Electron Spin–Lattice Relaxation Mechanisms of Nitroxyl Radicals in Ionic Liquids and Conventional Organic Liquids: Temperature Dependence of a Thermally Activated Process
A detailed understanding of the electron-spin relaxation mechanisms in polarizing agents used for DMP-NMR spectroscopy is crucial for the understanding of the DNP process and to optimize polarizing agents for different DNP applications. The entire study was performed at X-Band frequencies (9 GHz, 14 MHz 1H) and provides many details about the relaxation behavior of nitroxide radicals -...
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07-08-2015 11:11 PM
Hyperpolarization of "Neat" Liquids by NMR Signal Amplification by Reversible Exchange
From The DNP-NMR Blog:
Hyperpolarization of "Neat" Liquids by NMR Signal Amplification by Reversible Exchange
Shchepin, R.V., et al., Hyperpolarization of "Neat" Liquids by NMR Signal Amplification by Reversible Exchange. J Phys Chem Lett, 2015. 6(10): p. 1961-1967.
http://www.ncbi.nlm.nih.gov/pubmed/26029349
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06-09-2015 08:18 AM
Dynamic Nuclear Hyperpolarization in Liquids
From The DNP-NMR Blog:
Dynamic Nuclear Hyperpolarization in Liquids
Günther, U., Dynamic Nuclear Hyperpolarization in Liquids, in Modern NMR Methodology, H. Heise and S. Matthews, Editors. 2013, Springer Berlin Heidelberg. p. 23-69.
http://dx.doi.org/10.1007/128_2011_229
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07-18-2013 12:39 AM
Field-cycling NMR relaxometry of viscous liquids and polymers
Field-cycling NMR relaxometry of viscous liquids and polymers
May 2012
Publication year: 2012
Source:Progress in Nuclear Magnetic Resonance Spectroscopy, Volume 63</br>
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Graphical abstract
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12-15-2012 09:51 AM
Field-cycling NMR relaxometry of viscous liquids and polymers
Field-cycling NMR relaxometry of viscous liquids and polymers
May 2012
Publication year: 2012
Source:Progress in Nuclear Magnetic Resonance Spectroscopy, Volume 63</br>
</br>
Graphical abstract
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12-01-2012 06:10 PM
Field-cycling NMR relaxometry of viscous liquids and polymers
Field-cycling NMR relaxometry of viscous liquids and polymers
Publication year: 2011
Source:Progress in Nuclear Magnetic Resonance Spectroscopy</br>
D. Kruk, A. Herrmann, E.A. Rössler</br>
Graphical Abstract
http://ars.sciencedirect.com/content/image/1-s2.0-S0079656511000586-fx1.jpg Graphical abstract Highlights
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03-09-2012 09:16 AM
Field-cycling NMR relaxometry of viscous liquids and polymers
Field-cycling NMR relaxometry of viscous liquids and polymers
Publication year: 2011
Source: Progress in Nuclear Magnetic Resonance Spectroscopy, In Press, Accepted Manuscript, Available online 27 August 2011</br>
D., Kruk , A., Herrmann , E.A., Rössler</br>
Graphical abstract
*Graphical abstract:**Highlights:*? NMR relaxometry compared with DQ NMR, dielectric spectroscopy and light scattering ? Applying susceptibility representation and frequency-temperature superposition ? Liquids: Intra- & intermolecular relaxation give rotational & translational correlation times ? Polymers:...