Microfluidic technology widely used in generating monodisperse emulsion droplets often suffers from complexity, scalability, applicability to practical fluids, as well as operation instability due to its susceptibility to flow perturbations, low clearance, and depletion of surfactants. Herein, we present a monolithic 3D-printed step-emulsification device (3D-PSD) for scalable and robust production of high viscosity emulsion droplets up to 208.16 mPa s, which cannot be fully addressed using conventional step-emulsification devices. By utilizing stereo-lithography (SLA), 24 triangular nozzles with a pair of 3D void flow distributors are integrated within the 3D-PSD to ensure uniform flow distribution followed by monodisperse droplet formation. The outlets positioned vertically downward enables gravity-assisted clearing to prevent droplet accumulation and thereby maintain size monodispersity. Deposition of silica nanoparticles (SiNP) within the device was also shown to alter the surface wettability from hydrophobic to hydrophilic, enabling the production of both water-in-oil (W/O) as well as oil-in-water (O/W) emulsion droplets, operated at a maximum production rate of up to 50 mL h⁻¹. The utility of the device is further verified through continuous production of biodegradable polycaprolactone (PCL) microparticles using O/W emulsion as templates. We envision that the 3D-PSD presented in this work marks a significant leap in high-throughput production of high viscosity emulsion droplets as well as the particle analogs.

中文翻译：

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用于放大生产高粘度乳液液滴的整体式重力辅助步进乳化装置的 3D 打印


广泛用于生成单分散乳液液滴的微流控技术通常具有复杂性、可扩展性、对实际流体的适用性以及操作不稳定性等问题，因为它容易受到流动扰动、低间隙和表面活性剂消耗的影响。在此，我们提出了一种整体式 3D 打印分步乳化装置 （3D-PSD），用于可扩展且稳健地生产高达 208.16 mPa s 的高粘度乳液液滴，这是使用传统分步乳化装置无法完全解决的。通过利用立体光刻 （SLA），24 个三角形喷嘴和一对 3D 空隙流分配器集成在 3D-PSD 中，以确保均匀的流动分布，然后形成单分散液滴。垂直向下放置的出口可实现重力辅助清除，以防止液滴积累，从而保持尺寸的单分散性。二氧化硅纳米颗粒 （SiNP） 在装置内的沉积还表明，表面润湿性从疏水变为亲水，从而能够生产油包水 （W/O） 和水包油 （O/W） 乳液液滴，最大生产速率高达 50 mL ^h-1。通过使用 O/W 乳液作为模板连续生产可生物降解的聚己内酯 （PCL） 微粒，进一步验证了该设备的实用性。我们设想，这项工作中提出的 3D-PSD 标志着高粘度乳液液滴和颗粒类似物的高通量生产方面的重大飞跃。