title: Up to 100% Improvement in Dynamic Nuclear Polarization Solid-State NMR Sensitivity Enhancement of Polymers by Removing Oxygen.
abstract: High-field dynamic nuclear polarization (DNP) has emerged as a powerful technique for improving the sensitivity of solid-state NMR (SSNMR), yielding significant sensitivity enhancements for a variety of samples, including polymers. Overall, depending upon the type of polymer, the molecular weight, and the DNP sample preparation method, sensitivity enhancements between 5 and 40 have been reported. These promising enhancements remain, however, far from the theoretical maximum (>1000). Crucial to the success of DNP SSNMR is the DNP signal enhancement (εDNP ), which is the ratio of the NMR signal intensities with and without DNP. It is shown here that, for polymers exhibiting high affinity toward molecular oxygen (e.g., polystyrene), removing part of the absorbed (paramagnetic) oxygen from the solid-state samples available as powders (instead of dissolved or dispersed in a solvent) increases proton nuclear relaxation times and εDNP, hereby providing up to a two-fold sensitivity increase (i.e., a four-fold reduction in experimental time).
authors.affiliation: Aix-Marseille Université, CNRS, ICR (UMR 7273), 13397, Marseille cedex 20, France.
authors.forename: Dao
authors.initials: D
authors.lastname: Le
authors.affiliation: Aix-Marseille Université, CNRS, Centrale Marseille, Fédération des Sciences Chimiques (FR 1739), 13397, Marseille cedex 20, France.
authors.forename: Fabio
authors.initials: F
authors.lastname: Ziarelli
authors.affiliation: Aix-Marseille Université, CNRS, ICR (UMR 7273), 13397, Marseille cedex 20, France.
authors.forename: Trang N T
authors.initials: TN
authors.lastname: Phan
authors.affiliation: Aix-Marseille Université, CNRS, ICR (UMR 7273), 13397, Marseille cedex 20, France.
authors.forename: Giulia
authors.initials: G
authors.lastname: Mollica
authors.affiliation: Aix-Marseille Université, CNRS, ICR (UMR 7273), 13397, Marseille cedex 20, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Thureau
authors.affiliation: Bruker Biospin SAS, 67200, Wissembourg, France.
authors.forename: Fabien
authors.initials: F
authors.lastname: Aussenac
authors.affiliation: Aix-Marseille Université, CNRS, ICR (UMR 7273), 13397, Marseille cedex 20, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Ouari
authors.affiliation: Aix-Marseille Université, CNRS, ICR (UMR 7273), 13397, Marseille cedex 20, France.
authors.forename: Didier
authors.initials: D
authors.lastname: Gigmes
authors.affiliation: Aix-Marseille Université, CNRS, ICR (UMR 7273), 13397, Marseille cedex 20, France.
authors.forename: Paul
authors.initials: P
authors.lastname: Tordo
authors.affiliation: Aix-Marseille Université, CNRS, ICR (UMR 7273), 13397, Marseille cedex 20, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Viel
mesh_terms: D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D010100:Oxygen / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*
chemical_list: D011108:Polymers; D010100:Oxygen
keywords: dynamic nuclear polarization; oxygen; polymers; sensitivity; solid-state NMR