The 140-GHz (D-band) saturation transfer electron paramagnetic resonance studies of macromolecular dynamics in...

The high-field/high-frequency (5 T, 140 GHz) saturation transfer electron paramagnetic resonance (ST-EPR) method was used for the study of superslow librational macromolecular dynamics in various conducting polymers. It was shown that the increase of the electron precession frequency allows separate determination of spin relaxation and dynamics differently affecting effective ST-EPR spectra. Higher microwave frequency increases significantly the spectral resolution of the method and its sensitivity to the anisotropic macromolecular motion in conducting polymers. This broadens the interval of correlation time measured, thereby extending the slow-motion limit for ST-EPR by at least 2 orders of magnitude compared with convenient waveband EPR.