本研究觀察液滴撞擊固體平板後氣泡捕捉的行為，與液滴撞擊固體平板後的液滴形態學。藉由控制液滴大小(D0)與撞擊速度(Vi)，我們對純水液滴暨乙醇水溶液液滴撞擊parafilm表面產生的氣泡捕捉行為進行一系列的探討。利用高速攝影機從45°俯視觀察液滴之形態變化，可觀察到氣泡捕捉之操作條件僅限於在Vi - D0圖上的一個半封閉的區間。可捕捉到氣泡之撞擊速度的上限和下限，因著D0之增加而下降。被捕捉的氣泡在狀態穩定後，在parafilm表面上形成一近似半圓形氣泡。當撞擊速度接近上下限時，氣泡的尺寸會變小。另外，在純水-parafilm系統中，我們觀察到有四種氣泡形成機制。以5%及20%乙醇水溶液液滴撞擊parafilm表面，觀察到5%乙醇液滴在Vi - D0圖上具有一個封閉的氣泡捕捉區間，且皆以同一種方式捕捉氣泡；而20%乙醇液滴則無氣泡捕捉的行為。
分別以純水、乙醇和甘油水溶液液滴撞擊parafilm表面，在雷諾數與韋伯數一致時，三種不同液滴在擴展階段時，具有幾乎相同的液滴形態變化。另外，本研究亦以純水撞擊不同表面親疏水性（表面粗糙度）之石墨平板，觀察其表面親疏水性對液滴潤濕行為的差異。其中，當純水液滴撞擊接觸角約90°的石墨平板時，液滴向外擴展達到最大潤濕直徑後，接觸點即幾乎不再移動。

This study is observing the behavior of air bubble entrapment and the morphology of drop impingement. Controlling the droplet impact velocity(Vi) and drop size(D0), pure water droplets and C2H5OH(aq) droplets impacting on parafilm surface were systematically investigated. By using a high-speed video camera system from 45 degree top view, successful observation of the bubble entrapment occurred in a half closed region on Vi - D0 diagram. The upper and lower boundaries of impact velocities showed a tendency of decreasing as droplet diameter increases. Entrapped air formed a hemispherical bubble steadily settling on parafilm surface. In addition, four mechanisms were proposed in water on parafilm system. Change the solution to mixed water and ethanol. Make an observation of 5% C2H5OH (aq) and 20% C2H5OH (aq) impacting on parafilm surface. We observed a closed region of bubble entrapment for 5% C2H5OH (aq) on Vi - D0 diagram, and all trapped air bubble in the same way. However, there was no bubble entrapment for 20% C2H5OH (aq).
By individually using water, C2H5OH(aq), and glycerol aqueous solution impacting on parafilm surface, with consistent of Reynold number and Weber number, we observed that the three types of drop had similar morphology at spreading stage. Using graphite with different hydrophobicity as plane for pure water drop impingement, we observed the wetting behavior due to surface hydrophobicity difference. When the drop impacted on the graphite surface with contact angle around 90 degrees, we discovered that the contact point of drop do not change considerably when the drop spread outward to the maximum wetting diameter.

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