A portable modular acoustic streaming vortex platform for flexible and robust fabrication of monodisperse micromaterials.

Abstract

Droplet microfluidics is indispensable for precision fabrication of microscale functional materials, with broad applications in biomedical engineering, flexible electronics, and materials science. However, conventional microchannel-based systems suffer from high cost, complex fabrication, and nozzle-orifice-dependent size limitation, as well as the lack of robustness and flexibility to process complex fluids. To address these critical challenges, this research developed a modular acoustic streaming vortex (MASV) platform assembled from commercial off-the-shelf components. By synergistically modulating piezoelectric driving (PD) and amplitude modulation (AM) frequencies, the platform achieves ultra-broad size tunability (13-750 μm) of monodisperse microdroplets with a fixed nozzle (inner diameter of outlet ∼0.16 mm). Furthermore, studies have demonstrated that the MASV platform can efficiently process complex fluids (liquid metals and glycerol solutions) while exhibiting millisecond-scale real-time tunability and stable continuous operation for up to 8 hours. Notably, the study found that ejecting regime transition from dripping to jetting can be realized by reducing two-phase interfacial tension, thus supporting programmable fabrication of functional microfibers. This low-cost, versatile platform integrates modularity, nozzle-independent size control, complex fluid compatibility, and long-term stability, holding significant potential in flexible production of functional micromaterials.