International audienceThis work compares the overall sensitivity enhancements provided by dynamic nuclear polarization (DNP) for the solid-state NMR characterization of polymer samples doped with biradicals and prepared either by film casting (FC), or by glass forming (GF) using 1,1,2,2-tetrachloroethane as the solvent. Analysis of amorphous and semicrystalline polymers (polystyrene, poly(ethylene oxide), polylactide, poly(methyl methacrylate)) of varying molecular weights showed that GF provided larger sensitivity enhancements than FC but yielded DNP-enhanced 13C CPMAS spectra of lower resolution for semicrystalline polymers, owing to line-broadening due to conformational distribution of the polymer chains in frozen solution. Moreover, use of deuterated solvents significantly reduced the intensity of the solvent signals in the DNP-enhanced 13C CPMAS spectra of polymers prepared by GF, while preserving the sensitivity enhancement observed for the polymer signals. For the polymers investigated here, both FC and GF performed better than incipient wetness impregnation, yielding overall sensitivity enhancements between 5 and 40

International audienceDynamic nuclear polarization (DNP) is shownto greatly improve the solid-state nuclear magnetic resonance(SSNMR) analysis of synthetic polymers by allowing structuralassignment of intrinsically diluted NMR signals, which aretypically not detected in conventional SSNMR. Specifically,SSNMR and DNP SSNMR were comparatively used to studyfunctional polymers for which precise structural elucidation ofchain ends is essential to control their reactivity and toeventually obtain advanced polymeric materials of complexarchitecture. Results show that the polymer chain-end signals,while hardly observable in conventional SSNMR, could be clearly identified in the DNP SSNMR spectrum owing to the increasein sensitivity afforded by the DNP setup (a factor ∼10 was achieved here), hence providing access to detailed structuralcharacterization within realistic experimental times. This sizable gain in sensitivity opens new avenues for the characterization of“smart” functional polymeric materials and new analytical perspectives in polymer science