Low azeotropic solvent sealing of PMMA microfluidic devices

A new method for sealing PMMA-based microfluidic devices utilizing low azeotropic solvent, named DE-20, is developed. The bonding process can be achieved in 7 min at room temperature and can successfully bond microchannels as small as 40 /spl mu/m in width without clogging. Results show the bonding strength and the increased roughness of the surface after the bonding process are 3.8/spl plusmn/0.31 MPa (n=8) and 10 nm respectively. The achieved bonding strength is 17-fold larger than the conventional thermal bonding. Furthermore, the proposed method can seal a 3-mm wide microfluidic channel without collapsing the channels since no heating process is required in the bonding process. The bonding performance is confirmed by using a zigzag type passive microfluidic mixer. Results show that a high mixing efficiency can be achieved under a high driving pressure. More importantly, no leakage is observed under such high pressure.