INTEMA   05428
INSTITUTO DE INVESTIGACIONES EN CIENCIA Y TECNOLOGIA DE MATERIALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Organic-inorganic hybrid materials based on polyhedral (POSS) and bridged silsesquioxanes
Autor/es:
R. J. J. WILLIAMS
Lugar:
Bariloche
Reunión:
Workshop; USA-Argentina Workshop on Nanomaterials; 2009
Institución organizadora:
UBA
Resumen:
Organic-inorganic hybrid materials based on polyhedral (POSS) and bridged silsesquioxanes   R. J. J. Williams     Institute of Materials Science and Technology (INTEMA), University of Mar del Plata and National Research Council (CONICET), Av. J. B. Justo 4302, 7600 Mar del Plata, Argentina e-mail: williams@fi.mdp.edu.ar     Abstract   The hydrolytic polycondensation of an organotrialkoxysilane bearing a bulky organic group that forms intramolecular cycles with silanol groups leads to a distribution of polyhedral oligomeric silsesquioxanes (POSS). Functional groups present in the organic moiety may be used to generate a crosslinked polymeric matrix containing a dispersion of nanometric fillers (POSS). A monofunctional POSS that contains one methacrylate group in the structure may be blended with compatible methacrylate co-monomers to produce a molecular dispersion of POSS units in the final polymer through a fast free-radical polymerization. The partitioning of POSS moieties to the air-polymer interface generates hydrophobic coatings. Non-functional POSS or monofunctional-POSS that react slowly undergo a polymerization-induced phase separation leading to a micrometric dispersion of POSS-rich domains in the polymeric matrix. The hydrolytic polycondensation of precursors consisting of an organic group end-capped by two trialkoxysilane groups leads to bridged silsesquioxanes. Ordered clusters of the organic bridges may be formed by H-bonds or van der Waal forces. Proton-transfer through the H-bonded clusters may lead to photoluminescence with a maximum emission wavelength that can be tuned with the average size of the organic clusters. Incorporating hydrophobic pendant groups to a hydrophilic organic bridge leads to nanostructured materials with inorganic, hydrophilic and hydrophobic organic domains.