High-density coaxial emitter device for electrospray: pushing the limits of additively manufactured microfluidic devices by SLA/DLP

Photopolymerization-based 3D printing technologies like SLA and DLP offer efficient fabrication of diverse structures, eliminating the requirement for molds or machining. These techniques allow fast fabrication of intricate designs such as microfluidics devices at low cost, however, the accuracy and resolution of microchannels are still challenging to control for very intricate microfluidics. This study focuses on understanding the influence of manufacturing parameters on the quality of microchannels and miniaturization limits by developing a mathematical model to predict mechanical properties depending on the curing times. Also, we study the limits of this technology in terms of the accuracy of microchannels for the fabrication of multiplexed coaxial electrospray sources. We demonstrate the effectiveness of the mathematical model to improve the quality of these devices with diameters of 360 um with 41 unclogged coaxial nozzles in 1 cm2. The contribution of this work also demonstrated incorporating purge channels was essential to clean uncured resin and the proposed procedure to ensure proper cleaning of the device. The devices were electrically characterized via electrospray processes observing uniform array operation depending on the nozzle size.