Investigation of the density fluctuation in sol-gel derived materials by light scattering techniques
Abstract:The experimental methods for studying of small-angle light scattering in porous media and a theoretical model for understanding the observed density fluctuations are presented in this paper. Parameters describing the structure of silica sol-gel materials were calculated basing on the random density fluctuation theory. The correlation length a 1 and correlation length a 2 were found that represent the average pore diameter and average size of Si—O—Si string aggregates, respectively. For the studies described here, the sol-gel matrices were prepared on the way of acid hydrolysis. Two types of materials in form of sol-gel thin layers were examined: type I made with the water solvent and type II made with alcohol solvent. It was stated that the size of the macropores depends on the sol-gel preparation recipe. The type of solvent influences the porosity of sol-gel glasses. The analysis of the experimental data indicated the strong inhomogeneities of sol-gel material type I what results from the different degree of Si—O—Si polymerization.
Document Type: Original Article
Affiliations: 1: Bio-Optics Group, Institute of Physics Wrocław University of Technology, Wybrzeze Wyspiańskiego 27, 50370 Wrocław, Poland 2: Department of Biophysics, The Ludwik Rydygier Medical University, Jagiellońska 13, 85067 Bydgoszcz, Poland
Publication date: 2002-02-01