Application of dry film resist in the fabrication of microfluidic chips for droplet generation

The combined use of film transparency masks and dry laminar resist (Shipley 5038) has enabled the rapid fabrication of prototype devices for droplet generation. The resolution limit of structures in the resist was controlled by the type of mask (transparency or electron beam Cr mask), the density of the pattern in transparency masks (2400 or 5080 dpi) and the thickness of the resist in the range of 35-140 ?m. Flow-focusing devices with master patterns based on dry film resist were replicated as a Ni shim and hot embossed into Plexiglas 99524. These devices were used to generate oil/water droplets with a well-defined dependence of diameter and frequency on the flow parameters.