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A Comparative FTIR study of thermal and photo-polymerization processes in hybrid sol-gel films
No full textControlling the organic polymerization in organic-inorganic hybrids is a key point in the development of new materials with high homogeneity of the nanostructure. The main difficulty is related with the achievement of a simultaneous control of the organic and inorganic network formation. Thermal and photocuring represent the main routes to form the organic chains when polymerizable organic groups are present in the hybrid materials. In the present work hybrid organic-inorganic films were synthesized from 3-methacryloxypropyltrimethoxysilane (MPTMS) cohydrolyzed with tetraethylorthosilicate (TEOS) and N-[(3-trimethoxysilyl)propyl]ethylenediamine (TMESPE) or 3-(triethoxysilyl)-propylamine (TESPA). This an example of basic catalyzed hybrid material with a polymerizable methacrylate functionality whose micro-structure is modified by the amine groups. FTIR spectroscopy was used to compare the effects of thermal or photo-induced polymerization on the materials. TESPA and TMESPE showed a different catalytic effect on the condensation of the inorganic network, with TMESPE the more efficient one. The presence of a more extended silica backbone reduced the curing efficiency in TMESPE derived samples. UV curing was also very effective in catalyzing the inorganic condensation of un-reacted species still present in the film after the deposition. A photo-induced polymerization of the inorganic side was observed in the hybrid films. Thermal polymerization in TMESPE films induces the reaction between the secondary amine and C O bonds in MPTMS, this reaction is, instead, not observed in films cured by UV radiation
Crystallisation of Al2O3-TiO2 sol-gel systems
No full textAl2O3-TiO2 thin films and powders were synthesised from acid catalyzed sols of aluminium and titanium alkoxides containing acetyl acetone as a chelating agent. The crystallization of the system was studied as a function of the relative compositions and the firing temperature. Films of four different alumina-titania compositions (10, 20, 30 and 40mol% alumina) were prepared and fired at various temperatures in the range from 300 to 1000 °C. The films and powders were amorphous, at any composition, up to about 600 °C. Larger molar contents of Al2O3 were found to have an inhibitory effect on the crystallization of TiO2, while larger contents of TiO2 had only a weak influence on Al2O3 crystallization. The formation of a metastable BETA-Al2TiO5 phase was observed in films at 1000 °
Procedure di sintesi di materiali ibridi organico-inorganici col metodo sol-gel tramite reazione in due stadi non-idrolitico ed idrolitico
No full textBrevetto Italiano PD 99 A 00012
Ordered mesostructured silica films: effect of pore surface properties on its sensing applications
No full textPreface
No full textThis Special Issue is dedicated to the memory of Klaus
Muller.
This Special Issue focuses on Sol–Gel R&D in Italy,
with the purpose of giving a short overview of current
research trends in this field and presenting the main laboratories
working on sol–gel. The Italian community,
though it has a small number of researchers, has been one
of the most active in sol–gel research from the very
beginning.
The first International Sol–Gel Workshop of the series
was held in Padova, with several laboratories playing a
pivotal role in basic sol–gel research, which has been
widely recognized worldwide. This Issue also has the
purpose of increasing international collaborations along
with information on those who work in this field, and
hopefully should be the first of a series of Special Issues
dedicated to different countries. We would like to thank all
the contributors to this special Issue and in particular to the
Editor-in-Chief of the Journal of Sol–Gel Science and
Technology, Michel Aegerter, for his precious support.
We have dedicated this Special Issue to Prof. Klaus
Muller from the University of Trento who suddenly passed
away during the preparation of the Issue; it is an enormous
loss for our community and his family.
The Special Issue Editors
Plinio Innocenzi, Giovanna Brusatin, Antonio Aronne,
Sandra Dire`, Franca Morazzon
New synthetic route to 3-(Glycidoxypropyl)-trimethoxysilane based hybrid organic-inorganic materials
No full text- …
