Hybrid ethane-siloxane mesoporous materials with cubic symmetry

The structure of and synthesis conditions for an organic-inorganic hybrid mesoporous material, HMM-3, containing ethane fragments (-CH2CH2-) within the pore walls were studied. High resolution transmission electron microscope images and electron diffraction patterns obtained for different crystal axes of HMM-3 indicated that it was of the cubic Pm-3n space group, similar to mesoporous silica SBA-1. Scanning electron micrographs of HMM-3 in different directions confirmed that all of the produced HMM-3 particles had the crystal-like external morphology of a decaoctahedron (18-hedron) with six square {1 0 0} and 12 hexagon {1 1 0} planes with a cubic symmetry. The synthesis conditions for HMM-3 were optimized in a synthesis system comprising 1,2-bis(trimethoxysilyl)ethane (BTME), hexadecyltrimethylammonium chloride (C(16)TMA), sodium hydroxide (NaOH), and water (H2O). The highly ordered HMM-3 material was obtained at 95 degreesC with the mixture ratio of BTME:C(16)TMA:NaOH:H2O = 5.27:4.79:12:1773. The C(16)TMA/BTME ratio and C(16)TMA concentration affected the structural order of the produced mesophase, Only the cubic Pm-3n phase was formed even though the C(16)TMA/BTME ratio and the C(16)TMA concentration were varied with in wide ranges at 95 degreesC. (C) 2001 Elsevier Science B.V. All rights reserved.