Long-range ordered lamellar silicon based hybrid materials

Abstract

This paper concerns the polycondensation of the lamellar organized α,ω-organo-bis-silanetriols, 4,4′-bis(trihydroxysilyl)stilbene 1H, 4,4′-bis(trihydroxysilyl)diphenylacetylene 2H, 4,4′-bis(trihydroxysilyl)diphenylbuta-1,3-diyne 3H. A mild thermal polycondensation (180 °C) in the solid state leads to highly polycondensed (90%) non-porous solids (Ht) having a high density. As evidenced by X-ray powder diffraction analysis the initial organization of the starting bis-silanetriols on the nanometric scale is retained during the process. Moreover lamellar ordering into plates, observed in TEM, corresponds to a micrometric scale organization. An average size of the crystallites has been determined, corresponding to, respectively, 18 (1Ht) and 40 (2Ht and 3Ht) stacked layers per crystallite. These results show that it is possible, using the architecture of the molecular precursor as a scaffold, to prepare highly organized silicon based hybrid materials by a mild thermal polycondensation in the solid state.