Miscibility and dynamics of the poly(vinylimidazole-co-methyl methacrylate)-silica hybrids studied by solid-state NMR

Poly(vinylimidazole-co-methyl methacrylate)-silica hybrids, bonded through hydrogen bond (PVM-SiO₂) or chemical bond (PVM(5)-SiO₂) between organic and inorganic units, were prepared and characterized. The characterization of PVM-SiO₂ and PVM(5)-SiO₂ hybrids were confirmed by IR, ¹³C and ²⁹Si NMR spectra. The intermolecular interaction between copolymer chains was studied by the spin-lattice relaxation time in the rotating frame (T^H_1ρ), and that between copolymer and silica was evaluated by the time constant for energy change between ¹H and ²⁹Si spin system (T_SiH). T^H_1ρ and T_SiH values in PVM-SiO₂ hybrids were consistent with those in PVM(5)-SiO₂ hybrids, and those were independent of the silica content. Moreover, the T^H_1ρ values are in order of poly(methyl methacrylate)-silica hybrids (PMMA-SiO₂) ≧ PVM-SiO₂ ≒ PVM(5)-SiO₂ > polyvinylimidazole-silica hybrids (PVI-SiO₂), while those of T_SiH are in reverse order PMMA-SiO₂ ≦ PVM(5)-SiO₂ < PVI-SiO₂.