Organic-inorganic hybrid materials 6: NMR study of the polyvinylimidazole-silica hybrids

The microstructure of the polyvinylimidazole-silica hybrids (PVI-SiO2) cont aining various proportions of silica was examined by high resolution solid- state Si-29 and C-13 nuclear magnetic resonance spectroscopy. The Si-29-H-1 cross-polarization (CP) process revealed that the Q(3) and Q(4) species ha d different CP efficiency. Moreover, the time constant for the energy excha nge between H-1 and Si-29 spin systems (T-SiH) for the siloxane units was l ess dependent on the silica content, and that was in the range of 2.0 to 4. 0 ms. The spin-lattice relaxation time in rotating frame (T-1p(H)) of hybri ds suggested that the H-1 spin-diffusion between imidazole and siloxane uni ts were on a nanometer scale estimated by spin-diffusion path length.