Application of low-temperature substrate bonding in fabrication of reusable micro-fluidic devices

The plasma polymerised (PP) films were deposited on silicon substrates and used to bond the substrates at a low temperature (130 °C). Different types of monomers were used to deposit PP films on μ-electrode and μ-channel of micro-fluidic devices (MFD) to tailor the surface properties. To confirm the PP film deposition on the substrates the surface chemistry was characterized using X-ray photoelectron spectroscopy (XPS). The bond strength of about 100 nm PP acrylic acid, p-xylene, styrene, 1-vinyl-2-pyrrolininne and allylamine films were measured more than 2 Mpa. The bonding strength was also tested before and after passing the fluid in MDF and no significant change was observed. Generally, no change in the structure of μ-electrode was observed by the bonding, using a separating and cleaning process. Therefore, this bonding process is independent of the type of thin film deposited and the bonding can be easily carried out by me in the laboratory and the surface properties can be tailored for different applications. It also enables one to recycle and reuse the devices in production. This process allows the devices to be recycling and/or reusable for a better and cleaner global environment.