INTEMA   05428
INSTITUTO DE INVESTIGACIONES EN CIENCIA Y TECNOLOGIA DE MATERIALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Thermal evolution of silver doped silica-epoxy hybrid coatings
Autor/es:
RAÚL A. PROCACCINI; SERGIO A. PELLICE
Lugar:
Madrid
Reunión:
Conferencia; XVII International Sol-Gel Conference; 2013
Institución organizadora:
Internations Sol-Gel Society
Resumen:
The development of new materials with tailored functional properties holds a permanently increasing demand of the current consumer society. In this sense, the sol-gel science offers a wide range of advantages to produce functionalized coatings, whether through the use of organically modified alkoxydes or the incorporation of particles or additives. One of the areas in which this science offers a great potential is in the development of silver-doped coatings for biocide purposes. A primary obstacle found for the organically rich materials is the trend of silver to reduce and form particles, loosening its biocide character. In the present work an extensive analysis of the effect of different thermal treatments on the hybrid structure of an epoxy-modified silica network and the aggregation state of silver is presented. Hybrid materials were synthesized through the hydrolytic condensation of tetraethoxysilane (TEOS) and glycidoxypropyl-trimethoxysilane (GPTMS) in acidic media. Silica nanoparticles (LUDOX® AS-40) and (AgNO3) silver nitrate were alternatively used as additives. Sols were dip-coated onto glass slides and thermally densified in air and oxygen atmospheres at 50, 100 and 200 ºC. The use of Small Angle X-rays Scattering (SAXS), performed at the Synchrotron Light National Laboratory (LNLS, Brazil), was complemented with Fourier Transformed Infrared Spectroscopy (FTIR) and UV-visible spectroscopy. The developed hybrid structure of the sol-gel coatings consists in a spinodal-like matrix whose characteristic length, independently of the thermal treatment, tightly matches with the length of the organic chain of GPTMS. On the other hand, a high thermal sensitivity on the evolution of silver aggregates and the silica condensation process was observed.