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Dynamic nuclear polarization - enhanced high resolution solid-state NMR spectroscopy for atomic 3D structure determination of functionalized nanotubes and other nano-sized objects (DNP4NanoCarac)
Date du début: 1 avr. 2009, Date de fin: 31 mars 2011 PROJET  TERMINÉ 

This project aims at developing the instrumentation and methodology required to perform solid-state sub-nanometer scale structural studies by Nuclear Magnetic Resonance (NMR). In the last decades NMR has proven to be a priceless tool to probe structure and dynamics of systems as diverse as glasses, metal surfaces, polymers and proteins, etc. However, the low sensitivity of the technique currently limits its outreach in material science, chemistry and biology. In order to overcome this limitation, we plan to use a technique called Dynamic Nuclear polarization (DNP) which is able to hyperpolarize nuclear spins. The DNP phenomenon, discovered at low magnetic fields (< 0.3 T), is far from being new but its usage at high magnetic fields (5 to 20 T and more) constitutes an exciting ongoing challenge. Compared to traditional NMR where the signal originates from thermal polarization, DNP enables us to enhance the NMR signal to noise by 1 to 4 orders of magnitude (depending on the nuclei) by transferring the magnetization of unpaired electron spins (polarizing agents) to the surrounding nuclear spins. Utilizing emerging high frequency microwave technologies, optimized polarizing agents together with state of the high resolution solid-state NMR instrumentation and methods, we plan to develop original magnetic resonance experiments at high magnetic fields. This technique should allow bringing down the NMR detection threshold to micro/nano-molar concentration, studying larger molecular systems and performing multidimensional experiments orders of magnitude faster. The project will lead to numerous interdisciplinary applications to illustrate the potential of DNP-enhanced NMR to characterize new materials for the nanotechnologies (functionalized nanotubes, molecular wires, etc.), new polymers for energy (CNT embedded in polymers, etc.), and to determine the 3D atomic solid-state structure of biomolecules (membrane proteins, paramagnetic proteins, etc.).

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