Preparation of micro glass channels for micro-reactors by a chemical foaming process

A micro glass micro-reactor prepared by a chemical foaming process (CFP) is presented in this paper. By the CFP process, micro glass channels were simultaneously shaped on a glass wafer which consists of the following steps. First, shallow micro channels were etched in a silicon wafer followed by placing foaming agents in the silicon channels. Second, these silicon channels were sealed with a thin glass wafer by bonding a glass wafer. Third, the bonded wafers were heated to a temperature above the softening point of the glass and held for several minutes. The gas released by the foaming agents in the silicon cavities blew the softened glass to form a glass channel followed by cooling and annealing. Then, the hot-formed glass channels decorated by nano-sized catalysis, TiO2, were used as photocatalytic microfluidic reactors to exploit the application of the CFP-made micro glass channels. Methylene blue was filled into the micro glass channels followed by UV exposure to test the photocatalytic properties. Results showed that micro channels were prepared successfully. Results also indicate that the photocatalytic properties of nano-sized TiO2 were improved by using micro glass channels for their high specific area.