液滴微流體系統已廣泛應用於各種生物技術，由於可以把單個細胞包覆在微米級的液滴中，並且將每個液滴視為一個獨立的微反應器，同時進行大量的實驗和分析，因此大幅提高了實驗的效率和準確度，此外，每個液滴內的物質不受其他液滴和外界的影響，可獨立地進行分析研究，也能夠有效地減少樣品和試劑的浪費，所以在生物技術的研究和應用中具有重要的地位，然而，液滴的生成正是在應用時至關重要的基礎關鍵。本研究設計不同尺寸的T形微流道並製成微流體晶片，以正十六烷為連續相、去離子水為分散相，藉由調控體積流率在微流道中形成液滴，進一步探討液滴形成機制為squeezing時（Cac<0.01），流道中液滴的長度變化。
研究結果顯示，液滴長度與流率比的關係可表示為 L/W=β+α Qd/Qc。在同一個流道設計中，隨著體積流率比(Qd/Qc)的增加，液滴大小會增加，而流率值本身的不同會產生不同大小的液滴，當Qd/Qc<1時，不同Qd所產生的液滴大小較為相近。而在不同流道設計中， β值與w_in/w並沒有明確的關係，α值則根據Qd的大小有些不同，當Qd固定為0.04 ml/hr時，α值隨著w_in/w增加而增加，當Qd為0.1及0.5 ml/hr時，α值不隨w_in/w變化。另外，我們也進一步透過於液滴合併系統中加入界面活性劑的設計，達成液滴搜集的目標。

Droplet microfluidic systems revolutionize biotechnology by encapsulating individual cells in micrometer-sized droplets, enabling high-throughput experiments and analysis with improved efficiency and reduced waste. For the droplet microfluidics, generation of the desired droplet size is crucial for its applications. In this study, we fabricated T-junction microchannels with different dimensions to study droplet formation in the squeezing flow regime (Cac<0.01). Hexadecane and DI water were used as the continuous phase and the dispersed phase, respectively and the volumetric flow rates were varied to investigate droplet formation and its length.
The results showed that droplet length (L/W) relates to the flow rate ratio (Qd/Qc) as L/W = β + α Qd/Qc. Increasing Qd/Qc within the same channel design led to larger droplets. Different flow rates resulted in different droplet sizes, however, the droplet sizes were similar when Qd/Qc<1. It was also found that β was not related to channel dimensions, while α exhibited variations depending on Qd. α increased with win/w at Qd equal to 0.04 ml/hr but remained constant at Qd equal to 0.1 and 0.5 ml/hr. As to the proposed droplet merging system, the premature coalescence of the paired droplets downstream can be avoided by incorporating a branch channel filled with surfactants.

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