A FLEXIBLE METHOD FOR RAPID-PROTOTYPING OF PDMS MICROFLUIDIC CHIPS USING DIRECT-WRITING FOR GENERATION OF POLYMER-MASTER-STRUCTURES

We report a new, rapid and highly flexible method for the fabrication of master structures for casting of PDMS microfluidic chips. Conventional and time-consuming UV-lithographic fabrication of PDMS-molds is substituted by a direct-writing method to produce desired structures on planar, low-cost polyimide (PI) substrates by using a polymer dissolved in water. This technique facilitates the on-demand prototyping, requires no cleanroom and little training such that time-to-chip is reduced from typically ~24 h to less than 4 h. Structures exhibiting circular cross sections featuring dimensions from 110 to 340_μm in width and 6 to 100_μm in height have been fabricated to demonstrate the feasible range. The method was validated by fabrication of a PDMS microfluidic droplet generator.