Learning objectives
To provide the students with the basic knowledge of the sol-gel process for the production of inorganic materials <br />
In the laboratory, provide the students with an observative approach. Allow them to correlate the synthetical method with the material properties.
Prerequisites
Knowledge acquired in the courses of General and Inorganic Chemistry, Inorganic Chemitry, Organic Chemistry I, Organic Chemistry II
Course unit content
<p> 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. Electronic 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. <br />
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. <br />
<br />
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. <br />
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3) Mixed-oxides by the sol-gel method. Problems and examples. <br />
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4) The non-hydrolytic condensation. Reactions, mechanisms, precursors and some examples. <br />
</p>
<p>5) Properties of nanoparticles <br />
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shape, dimension, structure and density <br />
<br />
Characterization methods <br />
<br />
Applications <br />
<br />
Laboratory experiences: <br />
<br />
1) preparation of silica xerogels in different reaction conditions. Correlations between macroscopic properties and the structure of t he obtained materials. <br />
<br />
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. <br />
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3) Preparation of xerogels with embedded fluorescent molecules <br />
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4) Practical experiments of FTIR spectrophotometry: acquisition of spectra by trasmission techniques, (KBr pellet, nujol, solution), HATR (ZnSe and diamond crystals) and microspectrophotometry. <br />
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5) preparation of mixed oxides films on glass by dip-coating. Characterization by total reflection FTIR microspectrophotometry. <br />
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6) Preparation of glass fibers by sol gel method. <br />
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7) preparation of gold nanoparticles by reduction with sodium citrate. Preparation of a silica xerogel with embedded gold nanoparticles <br />
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8) preparation of nanoparticle of magnetite. Preparation of a silica xerogel with magnetic properties, containing embedded magnetite nanoparticles. Ferrofluidic properties in intense magnetic field</p>
<p>9) <br />
<br />
a) preparation of a conducting tin oxide glass surface <br />
<br />
b) preparation of nanocrystalline TiO2 <br />
<br />
c) assembly of a photovoltaic cell with TiO2 and phosensitizers</p>
Bibliography
J. D. Wright; N. A. J. M. Sommerdijk <br />
Sol Gel Materials: Chemistry and Applications <br />
Taylor and Francis, London <br />
ISBN: 90-5699-326-7 <br />
<br />
<br />
M. Hosokawa et al., editors, Nanoparticle Technology Handbook <br />
<br />
Elsevier; ISBN 978-0-444-53122-3 <br />
Teaching methods
Discussion of the laboratory report <br />
<br />
Oral exam <br />
