Immobilization of TiO2: via different routes for photocatalytic reactions in a PDMS based microreactor

In this study thin films of TiO2 were coated on silicon substrates by pipetting or spin coating from a colloidal suspension of Previously Made Titania Powder (PMTP). Influence of sintering temperature, steric stabilization, pH of the suspension, spin coating settings and P25 concentration on surface morphology, film quality and mechanical stability were analyzed by Scanning Electron Microscopy (SEM) and tape testing. Spin coated samples using a higher concentration of PVA (steric stabilizer) and sintered at 500-600 °C resulted in the most uniform, well-covered and mechanically stable films and were applied to a microreactor in which a coated silicon substrate was bound to a PDMS chip containing the microchannel. Dimensions of the channel were: 250 μm (Width) x 150 μm (Depth), 18 mm (Length) and a volume of 0.675 μL. The microreactor was used for photodegradation of Methylene Blue as the model compound under UV illumination. Degradation of up to 51.14% was achieved at a flowrate of 1 μl/min.