Characterization of PDMS Microchannels Using Horizontally or Vertically Formed 3D-Printed Molds by Digital Light Projection

Three-dimensional (3D) printing is one of the promisingtechnologiesfor the fabrication of microstructures due to its versatility, easeof fabrication, and low cost. However, the direct use of 3D-printedmicrostructure as a microchannel is still limited due to its surfaceproperty, biocompatibility, and transmittance. As an alternative,rapid prototyping of poly-(dimethylsiloxane) (PDMS) from 3D-printedmicrostructures ensures both biocompatibility and efficient fabrication.We employed 3D-printed molds fabricated using horizontal and verticalarrangement methods with different slice thicknesses in a digitallight projection (DLP)-based 3D printing process to replicate PDMSmicrochannels. The replicated PDMS structures were investigated tocompare their optical transmittances and surface roughness. Interestingly,the optical transmittance of PDMS from the 3D-printed mold was significantlyincreased via bonding two single PDMS layers. To evaluate the applicabilityof the replicated PDMS devices from the 3D-printed mold, we performeddroplet generation in the PDMS microchannels, comparing the same devicefrom a conventional Si-wafer mold. This study provides a fundamentalunderstanding of prototyping microstructures from the DLP-based 3D-printedmold.