Periodic Mesoporous Organosilica in Confined Environments

✍ Scribed by Andreas Keilbach; Markus Döblinger; Ralf Köhn; Heinz Amenitsch; Thomas Bein

• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 599 KB
• Volume: 15
• Category: Article
• ISSN: 0947-6539
• DOI: 10.1002/chem.200802216

✦ Synopsis

Abstract

Confined tubes: Periodic mesoporous organosilica (PMO) mesophases were synthesized within the confined tubular environment of anodic alumina membrane (AAM) channels, resulting in the formation of either the hexagonal circular or the cubic mesophase.magnified image

Periodic mesoporous organosilica (PMO) mesophases based on bis(triethoxysilyl)ethane (BTSE) were synthesized within the confined tubular environment of anodic alumina membrane (AAM) channels. The resulting mesophases were investigated by transmission small angle X‐ray scattering (SAXS), nuclear magnetic resonance (NMR), nitrogen sorption, and transmission electron microscopy (TEM). Two different surfactants—nonionic Brij 56 and ionic cetyltrimethylammonium bromide (CTAB)—were used in an acid‐catalyzed evaporation‐induced self‐assembly (EISA) process. Brij 56 as the structure‐directing agent (SDA) resulted in the formation of either the hexagonal circular or the cubic mesophase. While the hexagonal circular mesophase is common for such kinds of composites, the cubic mesophase has never been reported before. The template could be removed from the mesophases by template extraction and calcination after annealing the samples. When using CTAB as the SDA during EISA, the only mesophase observed was the hexagonal circular structure. This is in contrast to previous experiments and reports on pure silica mesophases, where the only mesophase formed with CTAB is hexagonal columnar.