SANS investigation of PDMS hybrid materials prepared by gamma-irradiation

The obtained materials are monolithic and transparent after drying in air. They had been previously characterized by thermal analysis, X-ray diffraction, Rutherford backscattering and elemental analysis. The present work reports a small angle neutron scattering study on a few samples of these materials to investigate their microstructure at the nanoscale. This study showed the presence of inorganic oxide regions with mass fractal structure, their size and fractal density increasing with the tetraethylortosilicate content. Although the presence of zirconium propoxide is required to obtain a stable hybrid material yet the increase in its content leads to less dense mass fractal oxide units. It was found that the structure of the oxide regions developed through a reaction-limited aggregation mechanism. The further addition of isopropanol in the sample preparation stage causes the inorganic fractal structure to extend over the whole sample.