Image: Microfluidic devices with 3DP?PDMS SL?printing. a) Bridge structures printed with 3DP?PDMS: characterization of exposure times required for creating roof structures on top of voids. The walls (2 mm wide, 2 mm high) are 3D?printed and the intervening areas are exposed with UV for different times. The uncured resin from the voids was later cleared with isopropyl alcohol. b) A microfluidic device with 500 µm wide channels SL?printed with 3DP?PDMS. c) A central stream of yellow dye (9 mL h?1) flanked by two streams of blue dye (9 mL h?1 each) produce a heterogeneous laminar flow (9 mL h?1) in the 3DP?PDMS microfluidic device.
Nirveek Bhattacharjee, Cesar Parra-Cabrera, Yong Tae Kim, Alexandra P. Kuo, Albert Folch
Advanced Materials. Volume 30, Issue 22, May 29, 2018.
The advantageous physiochemical properties of poly(dimethylsiloxane) (PDMS) have made it an extremely useful material for prototyping in various technological, scientific, and clinical areas. However, PDMS molding is a manual procedure and requires tedious assembly steps, especially for 3D designs, thereby limiting its access and usability. On the other hand, automated digital manufacturing processes such as stereolithography (SL) enable true 3D design and fabrication. Here the formulation, characterization, and SL application of a 3D?printable PDMS resin (3DP?PDMS) based on commercially available PDMS?methacrylate macromers, a high?efficiency photoinitiator and a high?absorbance photosensitizer, is reported. Using a desktop SL?printer, optically transparent submillimeter structures and microfluidic channels are demonstrated. An optimized blend of PDMS?methacrylate macromers is also used to SL?print structures with mechanical properties similar to conventional thermally cured PDMS (Sylgard?184). Furthermore, it is shown that SL?printed 3DP?PDMS substrates can be rendered suitable for mammalian cell culture. The 3DP?PDMS resin enables assembly?free, automated, digital manufacturing of PDMS, which should facilitate the prototyping of devices for microfluidics, organ?on?chip platforms, soft robotics, flexible electronics, and sensors, among others.