Mold Embossing<i>-</i>Based Soft Lithography for Fabrication of Complex Non‑rectangular Channels

This paper demonstrates a simple, flexible, and controllable technique to fabricate complex non-rectangular microchannels through the mold (e.g., balls) embossing-based soft lithography method. The good ductility of aluminum foil ensures the complete replication of the ball morphology, resulting in creation of the microchannels with a perfect circular cross section. By investigating the fabrication parameters such as the gap size and ball diameter, we can precisely control the width and height of the circular microchannel. More importantly, the method can be extended to create more complex channels with a series of cross-sectional shapes or combined channels through replacing the balls to the molds with various cross sections. Finally, the complex non-rectangular channels were designed and utilized to construct microfluidic valves and improve the mixing results of two liquids.