3D-Printed Step-Emulsification Platform for Scalable Production of Thermally Solidified Droplets

Microfluidic step-emulsification platform enables the generation of monodisperse emulsion droplets with high operational robustness through spontaneous droplet breakup at a step geometry. Recently, 3D-printed step-emulsification devices have been reported for scalable production of high-viscosity emulsion droplets, overcoming the fabrication complexity and low productivity of conventional microfluidic systems. However, a facile and scalable platform for processing highly viscous, temperature-dependent materials into large droplets remains needed. In this work, we report a 3D-printed microfluidic platform for scalable production of large thermally solidified droplets via step emulsification. The DLP 3D-printed device enables rapid optimization of nozzle geometry and parallelized structures for stable droplet generation. A thermally processable dispersed phase, which maintains fluidity at elevated temperature and solidifies upon cooling, is introduced to generate large droplets. The droplets are subsequently solidified without additional chemical crosslinking, providing a simple route to solidified emulsion-based particles that remain stable under ambient conditions. This platform offers design flexibility, simple fabrication, and potential scalability for controlled production of large droplets from high-viscosity materials. These thermally solidified droplets offer significant potential as functional microparticles and encapsulation carriers for advanced cosmetic materials.