In situ nano 3D printing of a microfluidic diode

Microfluidic components capable of mimicking the functions of electronic circuit elements are critical to applications including soft robots [1] and biochemical fluids processing [2-4]. The emergence of state-of-the-art additive manufacturing or “three-dimensional (3D) printing” technologies has afforded a level of submicron-scale geometric versatility that is not possible using conventional microfabrication techniques. Here we leverage these capabilities to 3D print microfluidic diode structures via Direct Laser Writing (DLW) in situ within polydimethylsiloxane (PDMS)-on-glass microchannels for the first time. Experimental results revealed Diodicities (Di's) ranging from 3.0±1.9 to 2.0±0.6 for 0.05 < Re < 0.25. These results suggest that the presented approach could be expanded upon to achieve the production of numerous additional nano3D printed microfluidic circuit components.