Résumé
Porous solids built of fractal clusters can be obtained by destabilization of quasi-monodisperse silica sols. Small-angle neutron scattering, associated with transmission-electron microscopy, was used for a structural investigation of these aerogels in a broad length scale. We present a quantitative analysis of the data for materials with different particle sizes and polydispersities. The analysis of the wavector region corresponding to the crossover between surface and volume scattering is especially emphasized.