Microwave plasma treatment of polymer surface for irreversible sealing of microfluidic devices

Microwave plasma was generated in a glass bottle containing 2 - 3 Torr of oxygen for plasma treatment of a polymer surface. A kitchen microwave oven'' and a dedicated microwave digestion oven were used as the power source. Poly( dimethylsiloxane) ( PDMS) slabs treated by a 30 W plasma for 30 - 60 s sealed irreversibly to form microfluidic devices that can sustain solution flow of an applied pressure of 42 psi without leaking. Experimental set up and conditions for the production of a homogeneous plasma to activate the PDMS surface for irreversible sealing are described in detail. The surface of a microwave plasma-treated PDMS slab was characterized using atomic force microscopy (AFM) and attenuated total reflection - Fourier Transform infrared spectroscopy (ATR-FTIR). The plasma-treated surface bears silica characteristics.