A microfluidic cross-flowing emulsion generator for producing biphasic droplets and anisotropically shaped polymer particles
A microfluidic cross-flowing emulsion generator for producing biphasic droplets and anisotropically shaped polymer particles
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DOI：
10.1007/s10404-009-0559-6
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发表时间：
2010-08-01
影响因子：
2.8
通讯作者：
Hatsuzawa, Takeshi
中科院分区：
文献类型：
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作者：
Nisisako, Takasi;Hatsuzawa, Takeshi
我们提出了一个微流控交叉流系统，用于生产两相乳液液滴和非球形聚合物微粒。玻璃芯片上的微流体通道包括Y形通道，以形成可光固化相和不可固化相的两相有机流，以及T形接头，以在交叉流动的水流中产生相分离的液滴。两相液滴在平衡时形成Janus配置（部分吞没）或核-壳配置（完全吞没）与最小化三个液相之间的界面自由能一致，根据三个铺展系数。当硅油用作不可固化相时，在一步法中可重复地产生单分散Janus液滴;例如，平均粒度为119 μ m，变异系数（CV）为1.9%。随后的UV引发的聚合产生具有受控凸/凹结构的单分散颗粒，其可通过改变两个有机相之间的流速比来调节。相比之下，当使用比硅油更疏水的全氟化碳流体作为不可固化相时，在两步方案中产生单分散核-壳液滴，导致在其表面上具有孔的交联聚合物壳的合成。我们还研究了如何不对称的流动配置影响液滴形成在T型接头。
We present a microfluidic cross-flowing system for producing biphasic emulsion droplets and non-spherical polymer microparticles. Microfluidic channels on a glass chip comprise a Y-shaped channel so as to form a two-phase organic stream of photocurable and non-curable phases, and a T-junction to generate phase-separated droplets in a cross-flowing aqueous stream. The biphasic droplets at equilibrium formed a Janus configuration (partial engulfing) or a core-shell configuration (complete engulfing) consistent with minimizing the interfacial free energies among the three liquid phases, according to the three spreading coefficients. When silicone oil was used as the non-curable phase, monodisperse Janus droplets were generated reproducibly in a one-step process; for e.g., the mean particle size was 119 mu m with a coefficient of variation (CV) of 1.9%. Subsequent UV-initiated polymerization yielded monodisperse particles with controlled convex/concave structures, which were tunable through variation of the ratio of the flow rates between the two organic phases. In contrast, when perfluorocarbon fluid, which is more hydrophobic than silicone oil, was used as the non-curable phase, monodisperse core-shell droplets were generated in a two-step regime, leading to the synthesis of cross-linked polymeric shells with a pore on their surfaces. We also investigated how the asymmetric flow configuration influenced droplet formation at the T-junction.