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Synthesis of Nanofiber-Based Silica Networks Mediated by Organized Poly(ethylene imine): Structure, Properties, and Mechanism†
Article first published online: 28 SEP 2006
Copyright © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Advanced Functional Materials
Volume 16, Issue 17, pages 2205–2212, November, 2006
How to Cite
Yuan, J.-J., Zhu, P.-X., Fukazawa, N. and Jin, R.-H. (2006), Synthesis of Nanofiber-Based Silica Networks Mediated by Organized Poly(ethylene imine): Structure, Properties, and Mechanism. Adv. Funct. Mater., 16: 2205–2212. doi: 10.1002/adfm.200500886
- Issue published online: 27 OCT 2006
- Article first published online: 28 SEP 2006
- Manuscript Revised: 21 FEB 2006
- Manuscript Received: 10 DEC 2005
- Nanofibers, inorganic;
- Nanotubes, inorganic;
- Template-assisted synthesis
Linear poly(ethylene imine) (PEI) can self-organize into fibrous aggregates with a crystalline core and a brushlike shell of ethyleneimine (EI) segments. Silicification from alkoxysilane mediated by PEI aggregates easily produces silica nanofibers (20–23 nm in diameter) with a core of axial, crystalline PEI filaments (5–7 nm in width) and a shell of silica (6–8 nm in thickness). Removing the axial filament of PEI from the silica nanofiber by calcination produces silica nanotubes. More interestingly, a nanowire-like platinum lining is formed in the silica nanofiber—a result of the PEI filament's ability to reduce PtCl42–. The degree of polycondensation, composition, and surface area of the resulting silica are investigated by 29Si magic angle spinning NMR spectroscopy, elemental analysis, and N2/He adsorption–desorption measurements. The time course of the reaction and the amount of silica source needed for silica-fiber formation confirm that silica deposition occurs exclusively and site selectively on the surface of the organized, fibrous PEI. Thus, the fibrous aggregates of PEI appear to be highly suitable for depositing silica fibers from both tetramethoxysilane and tetraethoxysilane.