Preparation of ordered macroporous ceramic films using PMMA microspheres as templates

Macroporous ceramic thick films of SnO2, TiO2 and MgO have been fabricated successfully by a modified sol-gel method employing polymethylmetbacrylate (PMMA) microspheres as a template. After PMMA microspheres with a uniform particle size (mean diameter: 870 run) were deposited on an oxidized silicon substrate by a dip-coating method, precursor solutions of Ti(i-C3H7O)(4) in isopropyl alcohol, SnCl2.2H(2)O in dehydrated ethanol, and MgCl2.6H(2)O in a mixture of ethanol and water were permeated into the openings of the template layer in vacuo, and then were air-dried at room temperature. The composite layers were subjected to heat treatment at 500 or 600degreesC in air in order to remove the core PMMA template by thermal decomposition. In the case of a macroporous SnO2 thick film, this heat treatment resulted in formation of a self-standing network of interconnected hollow SnO2 microspheres with a specific surface area of 41.8 m(2) g(-1). On the other hand, macroporous TiO2 and MgO thick films showed an ordered honeycomb pore structure with a specific surface area of 48.8 m(2) g(-1) and 5.4 m(2) g(-1), respectively.