Nuclear spin relaxation in a vinylidene fluoride and trifluoroethylene copolymer 70/30 - I. Dynamics and morphology in the ferroelectric phase

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Abstract
The spin dynamics of hydrogen and fluorine in a 70/30 VF2/TrFE copolymer have been investigated by the measurements of the nuclear spin-lattice relaxation times in the laboratory (T1) and rotating frames (Tθ1ρ) the transient Overhauser effect (TOE) and the free induction decay (FID). Tθ 1ρ results demonstrate the presence of local motions within the crystallites implying the existence of crystalline « defects ». A simple model treating cross-relaxation and spin diffusion on an equal footing was found to be appropriate to describe all the relaxation data in the laboratory frame. Moreover, it confirms that the high frequency motions in the amorphous phase below the Curie point and in the paraelectric phase are of the same type