abstract
Gamma-irradiation from a (60)Co source was used to prepare hybrid materials from a mixture of polydimethylsiloxane with tetraethylortosilicate and zirconium propoxide. 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. (C) 2008 Elsevier B.V. All rights reserved.
keywords
NETWORKS
subject category
Instruments & Instrumentation; Nuclear Science & Technology; Physics
authors
Gomes, SR; Margaca, FMA; Salvado, IMM; Falcao, A; Almasy, L; Teixeira, J
our authors
Isabel Margarida Miranda Salvado
Associate Professoracknowledgements
The authors wish to acknowledge support from the Portuguese Foundation for Science and Technology, FCT, in the framework of project POCTI/CTM/44150/2002. Support through the COST-539 Action is gratefully acknowledged. The neutron scattering experiments were supported by the European Commission (Contract No. RII3-CF-2003-505925).