Organically modified silicas: determination of their hydrothermal degradation mechanism and tuning of functional properties
Silica networks containing organic groups distributed at the molecular level show functional properties significantly different from unmodified silica. The combination of organic and inorganic segments yields a hybrid system that combines strengths of both classes, such as the high thermal and chemical stability of silica and the molecular flexibility and water stability of organics. Hybrid silicas can be prepared by mild and versatile sol-gel routes and application areas are i.e. molecular separation membranes1, catalysts2 and sensors3.
The general aim of this research project is to expand the understanding and engineering possibilities of hybrid silicas. For example, organic bridges as schematically shown in Figure 1 are known to extremely enhance the hydrothermal stability and this is very useful for membrane applications4, but the exact origin of this stability is unclear. A better understanding of stabilizing factors enables tuning of the stability for specific applications. Research involves molecular design (nature and location of organic groups in the silica network) as well as processing aspects (microstructure, environmental factors, patterning).
Figure 1 Schematic representation of a silica network with organic bridges.
1 J. Mem. Sci. 380, 124-131 (2011)
2 Angew. Chem. Int. Ed. 49, 184-187 (2010)
3 ACS Appl. Mater. Interfaces 5, 6854-6859 (2013)
4 J. Mater. Chem. 18, 2150-2158 (2008)