基于液滴微流控技术的复合乳粒形貌调控

Morphology control of composite emulsion based on droplet microfluidic technology

针对复合乳粒形貌结构难以精确调控的问题,提出一种基于微流控技术的“两步法”同轴乳粒发生装置来实现复合乳粒尺寸形貌精确制备的方法。研究三相流体的体积流量对复合乳粒尺寸及内液滴数目的影响规律,并依据流体流量与液滴体积之间的质量守恒,实现复合乳粒内液滴数目的精准预测;通过复合乳粒内液滴数目的调控,实现复合乳粒形貌结构的精确调控,并获得乳粒形貌关于三相流体体积流量的流型图。结果表明:三相流体体积流量会直接影响复合乳粒的形貌结构。复合乳粒外径、内液滴数目与外相体积流量负相关,内径与内相和中间相体积流量的比值正相关;且内、中两相体积流量比值越小,乳粒形貌越趋于球形。

Precise control of morphology and structure of composite emulsion has been widely studied. A "two-step" coaxial capillary emulsion generator based on microfluidic technology was proposed for accurate preparation of composite emulsion. Effects of volume flow rate of three-phase fluid on composite emulsion size and innermost droplet number were studied. The number of innermost droplets can be deduced accurately using the mass balance relationship between fluid flow rate and droplet volume. Furthermore, precise regulation of composite emulsion morphology was realized by controlling the number of innermost droplets, and the flow pattern diagram of emulsion morphology relevant to the three-phase rates was obtained. The results show that volume flow rate of three-phase fluid directly affects morphology and structure of the composite emulsion. The external diameter and the number of innermost droplets show a negative coefficient with the volume flow rate of the external phase, while the inner diameter shows a positive coefficient with the ratio of the volume flow rate of the inner phase and middle phase. Moreover, the morphology turned spherical with smaller volume flow ratio between inner phase and middle phase.