應用微流體技術製備微乳化液滴的方法在近年來已經被廣泛證實為極具潛力之研究方向。本研究整合T型管道、可控制式側壁結構與邊削流微流體元件形成一整合型微流體晶片，成功產生雙重乳化液滴，並可達成主動式的內層液滴數目之控制效果。首先，油包水乳化液滴藉由T型管道形成，接著當此液滴通過一個連有三條垂直支管道的微流體管道時，這些支管道能產生液滴均等分的效果。再配合能選擇性控制開關的側壁結構，數量由一到三個的均勻液滴能被順利產生。這些被形成的液滴接著會沿著管道流往出口，最後利用邊削流微流體元件以產生包含著不同數量內層液滴的雙重乳化包覆。研究結果顯示，於各種側壁結構作用情況下所產生的液滴極為均勻，直徑的變異係數都約在5%左右。進一步的配合了十條垂直支管道的微流體晶片也被利用以產生更多數目的均等分液滴，並同樣地實現多重乳化包覆。最後，利用T型管道所形成的液滴和與其相關之利用支管道所產生的均分液滴關係之實驗也被探討。由實驗結果可得知，經由適當調節內層水相與中層油相液體之流量，各種大小的均分液滴可被獲得。本實驗之結果可應用於化妝品、藥品與食品等之加工上。

Microfluidic technology has shown a reliable and promising new route for the formation of uniform emulsions in the past decade. In this thesis, a novel method for active control the internal droplet number of double-emulsion droplets was demonstrated. Moreover, various sizes of internal and external droplets were also successfully formed. This investigation presented a device integrated with T-junction, moving wall structure, and sheath-flow junction components, utilizing in water-in-oil-in-water (W/O/W) multiple emulsions. During the process, inner water-in-oil (W/O) single-emulsion droplets were formed by a T-junction design first, and then the droplets were subdivided into smaller droplets with equal size by passing through a microchannel connected with a series of T-junctions (3 branches). Meanwhile, the moving wall structures beside the branches could be exploited to control the number of the subdivided droplets by alternative blocking or releasing the branches. Following these steps, a certain number of subdivided droplets could be formed, and then moved out together. Finally, double-emulsion droplets with 1, 2 or 3 internal droplets were formed by using a sheath-flow junction microfluidic device. Experiment data demonstrated that the inner and outer droplets could have narrow size distributions with coefficients of variation in diameter of approximately 5%. At last, another extended design with 10 branches was used to subdivide a water-in-oil droplet into 10, and formed uniform double emulsions with 10 inner droplets. Relationships between the inner droplets formed by T-junction at inlet and the relevant sub-droplets formed by T-junctions at outlet were proved. Based on the results, sub-droplets with various sizes could be obtained by adjusting the relative flow rates of R1 (inner phase) and R2 (middle phase). The developments of these microfluidic devices are promising for a variety of applications in the cosmetics, pharmaceutical, and food industries.

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