The structure of hybrid gels by drift and NMR spectroscopies

Hybrid inorganic-organic gels have been prepared by the sol-gel process usi ng tetraethoxysilane (TEOS) as precursor, mixed with a low concentration of polytetrahydrofuran (PTHF), under acid catalysis. The hybrid xerogels were characterized by DRIFTS and Solid State H-1, C-13 and Si-29 NMR. The DRIFT spectra indicate that the polymer is responsible for decreasing the number of free silanol groups in comparison to pure silica. Solid-state NMR spect ra reveal the types of silicate structures formed and the conditions for es tablishing chemical bonds between the two phases, which are responsible for the silica network flexibility. We have concluded that it is possible to d esign a hybrid gel with tailored properties, even at very low polymer conce ntration, by selecting the appropriate preparation route.