Optical transmission properties of silica aerogels prepared from polyethoxidisiloxanes
| Autor: | E. Elaloui, Bruno Chevalier, Gerard Pajonk, R. Begag |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Range (particle radiation)
Materials science business.industry Analytical chemistry Aerogel Condensed Matter Physics Supercritical fluid Electronic Optical and Magnetic Materials Catalysis Solvent Transmission properties Optics Extinction (optical mineralogy) Materials Chemistry Ceramics and Composites Visible range business |
| Zdroj: | Journal of Non-Crystalline Solids. 210:224-231 |
| ISSN: | 0022-3093 |
| DOI: | 10.1016/s0022-3093(96)00600-x |
| Popis: | Transparent, crack-free low density silica monolithic aerogels synthesized from a series of polyethoxidisiloxanes have been characterized in the UV-visible-NIR optical range (0.3–2.5 μm). Normal hemispherical transmittances in the visible range τvnh were measured as well as extinction coefficients at 550 nm. These quantities are valuable parameters to quantify the image quality seen through a piece of aerogel by an empirical index called the transparency ratio (TR). The transparency ratios depend upon catalysis, volumic percentage of solvent and chemical nature of precursors, at the sol–gel step, as well as the supercritical temperature of drying and the sample thickness. Results show that the transparency ratio of the best aerogel is relatively close to that of a simple window pane of comparable thicknesses (0.92 versus 0.99, respectively) while their respective extinction coefficients at 550 nm are similar (16.3 m−1 versus 16.4 m−1, respectively). |
| Databáze: | OpenAIRE |
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