2 mm waveband saturation transfer electron paramagnetic resonance of conducting polymers

The 2 mm waveband (140 GHz) saturation transfer electron paramagnetic resonance (ST-EPR) spectroscopy has been employed to characterize the very slow microsecond to millisecond librational macromolecular dynamics of a wide range of conducting polymers. It is possible at this waveband to determine separately spin relaxation and dynamics affecting ST-EPR spectra. Higher microwave frequency provides substantial increases sensitivity of the method to the anisotropic macromolecular motion in conducting polymers and broadens the interval of correlation times up to 1-80 ms, thereby extending the slow-motion limit for ST-EPR by two orders of magnitude compared with convenient wavebands EPR. (C) 2008 American Institute of Physics.