Periodic mesoporous organosilica in confined environments.
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.
Keilbach
Andreas
A
Department of Chemistry and Biochemistry and Center for NanoScience (CeNS), University of Munich, Butenandtstrasse 5-13 (E), 81377 Munich, Germany.
Döblinger
Markus
M
Köhn
Ralf
R
Amenitsch
Heinz
H
Bein
Thomas
T
D000537:Aluminum Oxide; D009682:Magnetic Resonance Spectroscopy; D008567:Membranes, Artificial; D046529:Microscopy, Electron, Transmission; D016062:Porosity; D012821:Silanes / Q000138:chemical synthesis* / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry*
D008567:Membranes, Artificial; D012821:Silanes; D013501:Surface-Active Agents; C515211:1,2-bis(triethoxysilyl)ethane; D000537:Aluminum Oxide