200 MHz DNP NMR spectroscopy with a 131 GHz gyrotron for the analysis of polymer surface

Dynamic nuclear polarization (DNP) with a 131.5 GHz gyrotron (Gyrotron FU CW IV) has achieved enhancement factor of around 30 by using stable mono-radical 4-amino-TEMPO for 200 MHz high-resolution solid-state NMR spectroscopy for the analysis of polymer surface. Dependencies of the enhancement factor on irradiation time of the gyrotron output, the power of irradiation, cooling time, and irradiation frequency are examined. Application of the 200 MHz DNP NMR spectroscopy to the analysis of polymer surface is also presented briefly.