Ultrastable Mesostructured Silica Vesicles
Seong Su Kim,
Wenzhong Zhang,
Thomas J. Pinnavaia
*
A family of mesoporous molecular sieves (denoted MSU-G) with
vesiclelike hierarchical structures and unprecedented thermal (1000°C) and hydrothermal stabilities (more than 150 hours at 100°C) associated with high SiO4 cross-linking was
prepared through a supramolecular assembly pathway that relies on
hydrogen bonding between electrically neutral gemini surfactants of the
type
CnH2n+1NH(CH2)2NH2 and silica precursors derived from tetraethylorthosilicate. The vesicle shells are constructed of one or more undulated silica sheets
that are about 3 nanometers thick with mesopores (average diameters
from 2.7 to 4.0 nanometers) running both parallel and orthogonal to the
silica sheets, which makes the framework structure bicontinuous and
highly accessible. Catalytic metal ion centers [for example,
Ti(IV) and Al(III)] have been incorporated into the framework
with the retention of hierarchical structure.
Department of Chemistry and Center for Fundamental Materials
Research, Michigan State University, East Lansing, MI 48824, USA.
*
To whom correspondence should be addressed. E-mail:
Pinnavai{at}cem.msu.edu
