Additively manufactured arrays of triaxial electrospray emitters for scalable generation of core-shell-shell microdroplets

We report the first proof-of-concept demonstration of monolithic arrays of triaxial electrospray emitters for scalable production of core-shell-shell microdroplets. The devices are made via vat photopolymerization and contain a complex network of three-dimensional microchannels that supply in parallel three immiscible liquids to a plurality of triaxial nozzles, enabling the controlled generation of uniform, three-layered microdroplets via electrohydrodynamic jetting. Designs with up to 16 nozzles in 1 cm² of active area were demonstrated. Experimental results show stable operation with consistent per-emitter behaviour across emitter arrays of different size, while operating the devices in the electrospray cone-jet mode. The capability of the devices to generate core-shell-shell microdroplets with tunable layer thicknesses via flow rate and voltage control was verified via fluorescence microscopy and current-versus-flow rate measurements. The reported devices demonstrate a flexible, scalable, and low-cost approach for microencapsulation enabled by additive manufacturing to satisfy applications such as micro- and nano-enabled drug delivery, food science, and functional material synthesis.