P 02/02


Multifunctional precursor derived ceramics prepared by freeze casting technique

Monolithic hybrid ceramics and SiOC ceramics with different pore size distributions will be developed by adapting the freeze casting process to the manufacturing of polymeric siloxane precursors and emulsions. As pore forming agent water should be applied, since a water based process is environmental friendly and water can be removed rather easily under freeze drying conditions. After freezing and cross-linking the materials will be pyrolyzed at different temperatures. Beside the adjustment of several pore structures by varying the process parameters such as freezing temperature / freezing velocity or the freezing direction (multi- or unidirectional) the introduction of further properties will be studied. The surface characteristic will be altered in terms of hydrophilicity and hydrophobicity to adjust the surfaces to special requirements of adsorption and catalyst application by applying different pyrolysis temperatures or varying precursor compositions. At the same time the mechanical stability of the monoliths should be improved by changing the precursor and using filler particles. These structures will be tested in capillary transport experiments or as filtration unit. In the second part of the project even more complex compositions will be studied. By adding metal salts to the precursors, to generate metal nanoparticles during the pyrolysis process, materials for catalytic application will be synthesized. By carefully adjusting the hierarchical porosity, the surface characteristic and the catalytic properties new monolithic multifunctional structures for adsorption technique and heterogeneous catalysis will be synthesized.

Contact: Wilhelm, Schumacher