Superhydrophilic titania wall coating in microchannels by in situ sol-gel modification

An in situ reaction sol-gel method to synthesize superhydrophilic titania films in silicon microchannels at room temperature is reported. Superhydrophilic surface can be realized on TiO2 films with thickness less than 10 nm. The water flow velocity in the TiO2-coated silicon channels reached almost 4 times of the velocity in SiO2-coated channels. The ultra-thin superhydrophilic TiO2 films fabricated by this method show the ability to strongly improve the capillary of microchannels without affecting the morphology of the channel walls, indicating potential applications to biomolecule analysis and surface tension driven microfluidic systems. Due to its low operating temperature, this method is also suitable for polymer microstructures such as PDMS and PMMA microfluidic chips.