LABORATORY FOR INORGANIC MATTER CHEMISTRY
Learning outcomes of the course unit
To provide the students with the basic knowledge of the sol-gel process for the production of inorganic materials
In the laboratory, provide the students with an observative approach. Allow them to easily correlate the synthetical method with the material properties.
Course contents summary
The inorganic polymers. Basics of the chemistry of the sol-gel process; the precursors: the chemistry of silicon, chlorides and alkoxides, preparation and pshysico-chemical properties; the definition of sol and gel. The reactions of hydrolisys and condensation.The alcogels. Influence of the reaction parameters on the formation of silicon based inorganic gels. Elctronic and steric effects of the substituents, solvent effect, concentration effect, water-silicon ratio, the catalyst effect, the drying methods. Properties of gels, xerogels and aerogels and their technologic uses.
Characterization techniques for the materials obtained by the sol-gel method: FTIR spectrophotometry, light dispersion thecniques, surface area measurements, solid state NMR, CHNS-O microanalysis, electronic microscopies SEM and TEM.
2) The Inorganic-Organic hybrid materials. Calssifications and examples. Preparation of the precursors, silicon based hybrid materials obtained by sol-gel method, characterization. Definition of interphase. Polysesquioxanic materials with polyhedric structure. Applications of hybrid materials.
3) Mixed-oxides by the sol-gel method. Problems and examples.
4) The non-hydrolytic condensation. Reactions, mechanisms, precursors and some examples.
1) preparation of silica xerogels in different reaction conditions. Correlations between macroscopic properties and the structure of t he obtained materials.
2) preparation by sol-gel method of hybrid materials containing mono- bi and tri-dentate amines. Use of the xerogels as metal absorbants for acqueous solutions. Coordination chemistry on a supported phase.
3) Preparation od transition metal molibdates supported on silica xerogel by the sol-gel method. Stabilization of metastable phases.
4) Practical experiments of FTIR spectrophotometry: acquisition of spectra by trasmission techniques, (KBr pellet, nujol, solution), HATR (ZnSe and diamond crystals) and microspectrophotometry.
5) preparation of mixed oxides films on glass by dip-coating. Characterization by total reflection FTIR microspectrophotometry.
6) Preparation of glass fibers by sol gel method.
J. D. Wright; N. A. J. M. Sommerdijk
Sol Gel Materials: Chemistry and Applications
Taylor and Francis, London
Discussion of the laboratory reports.