Abstract
Silica sols have been prepared in an alcoholic solution by hydrolysis and condensation of TEOS (tetra-ethyl-ortho-silicate) molecules as a function of water and nitric acid concentration. The polymers are intended as precursors for ceramic, gas separation membranes. These molecules show fractal behavior as determined by SAXS (Small Angle X-ray Scattering). Microporosity of dried and calcined silica polymers is determined by N2-adsorption at 77 K. Fractal dimension and porosity increase with increasing acid concentration. Both the sol structure and the drying kinetics determine the porosity values. N2-adsorption isotherms are not very suitable for the determination of pore size distributions of microporous silica.
| Original language | English |
|---|---|
| Pages (from-to) | 471-475 |
| Number of pages | 5 |
| Journal | Journal of sol-gel science and technology |
| Volume | 8 |
| Issue number | 1-3 |
| DOIs | |
| Publication status | Published - 1997 |
Keywords
- Polymeric sol
- Microporous silica
- Membranes
- N2-adsorption
- Fractals