Hierarchical Biosilicates by the 3-D Replication of Block Copolymer Templates in Supercritical Fluids
Final performance rept. 1 Dec 2005-30 Nov 2008
MASSACHUSETTS UNIV AMHERST DEPT OF POLYMER SCIENCE AND ENGINEERING
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Unique methods for the encapsulation of biologically-derived materials within ordered mesoporous silica films, the preparation of mesoporous silica films using a biodegradable template system, and the preparation of thermally stable, mesoporous silica spheres with tunable diameters ranging from 40 nm to 560 nm, narrow size distributions on the order of 10, surface areas greater than 1000 m2g, and pore volumes on the order of 1 ccg were demonstrated. The stable spheres were synthesized using tetraethylorthosilicate at room temperature and near-neutral pH using cysteamine as the catalyst and cetyltrimethylammonium bromide CTAB as the structure directing agent in a mixed water and ethanol system. The pore walls were resistant to collapse at temperatures exceeding 750-deg C in air and upon hydrothermal treatment in boiling water for over 100 hours. Silica formed using bio-inspired small molecule catalysts including cysteamine, glutathione and methionine alone or in combination provided highly condensed silica networks at room temperature over a broad range of pH as evidenced by 29Si NMR.
- Inorganic Chemistry
- Polymer Chemistry