Nanostructured hybrid silica material

Thus the sol-gel methodology is an alternative to classical thermodynamic routes for the synthesis of solids. It is also evident that the preparation of the solids through Chimie Douce bridges molecular chemistry and solid state chemistry. This chapter will be focused on material prepared by the sol-gel process, where an organic part is associated with a silica or siloxane Si—O—Si network. Two types of organic-inorganic hybrid materials can be prepared by the sol-gel process and are completely different the nanocomposites and the nanostructured hybrid materials6-9. 

V. A. Bershtein, L. M. Egorova, P. N. Yakushev, P. Pissis, P. Sysel, and L. Brozova, Molecular dynamics in nanostructured polyimide-silica hybrid materials and their thermal stability, J. Polym. Sci. B 40, 1056-1069 (2002). 

Recently, living cells were reported to actively direct the assembly of lipid-silica nanostructures 78 extension of this cell-directed assembly (CDA) to hybrid architectures will add another level of organizational control to these materials. 

The first part on nanostructured amorphous hybrid materials is divided in two sections. First, new findings on coassembly mechanisms of mesostmetured block copolymer-silica-type hybrids are described. More specifically, the influence of nanoparticle... 

This new family of mesoporous silica and aluminosilicate compounds were obtained by the introduction of supramolecular assemblies. Micellar aggregates, rather than molecular species, were used as structure-directing agents. Then, the growth of inorganic or hybrid networks templated by structured surfactant assemblies permitted the construction of novel types of nanostructured materials in the mesoscopic scale (2-100 nm) [110,113,117],... 

The pyrolysis of PESs within the channels of the mesoporous silica MCM-41 and the creation of nanostructured magnetic ceramic nanocomposite materials has been achieved. In addition, use of a sacrificial porous alumina yields organometallic and magnetic ceramic nanofibers. Hyperbranched PFSs have also been synthesized and pyrolysis of these interesting materials has been found to lead to superparamagnetic ceramics. Furthermore, pyrolysis of PFSs with pendant Co clusters yields ceramics containing hybrid Fe/Co nanoparticles. ... 

Lamellar nanostructures can be obtained by hydrolyzing TEOS in acidic mixtures ofperfluoroctane sulfonic acid, C8Fi7S03H, and3-aminopropyltriethoxysilane, APTES. The silica layers in the materials are very thin, and contain a relatively high concentration of attached aminopropyl groups. These hybrid fluorocarbon-silica nanocomposites are thermally stable, hydrophobic and show a low dielectric constant (around 2.8) which is almost independent of frequency [68]. 

Despite those differences, it appears clear that those two aerogel families present a common huge potential for hybridization with their nanostructured silica homologues, which could lead to, among others, brand new reinforced superinsulating materials. 

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