2008-08-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/705882摘要：微流體的理論和實驗的研究是動態生物晶片的基礎。因為微流體研究的液體量大約在10-9至10-12升之間，因此有很高的面體比，介面性質因此十分重要。此一個光微流體的計劃將進行半疏水性表面光熱液珠的趨動的研究。主要的致動力為熱毛細力(thermocapillary force)。光熱能之間的轉換將透過一非晶或微晶矽層，非晶或微晶矽有很強的吸光能力而將光轉換成熱，此一熱能可產生溫度梯度而趨動液珠。 這一個實驗關鍵在於表面鍍層的品質，而此一鍍層的品質和下方矽的結晶度有關。在電漿增益化學沈積製程中，我們將使用不同的製程氫氣比例來調整結晶度。同時利用表面分析工具，例如X光電子光譜儀 (XPS)、沾濕角量測儀、橢圓偏光儀和原子力顯微鏡等等分析表面，以找出最適合此光熱液趨動系統的結晶條件。 另一個液珠移動的重要課題是前置膜(precursor film)的存在與否。一般認為液體在展開於親水性表面之前有一前置膜，這一個膜的厚度在幾十奈米左右。然而當液珠於半疏水性的表面時，即使在液珠移動時，前置膜存在與否仍是個謎。在本實驗中，我們將利用另一雷射源去探測前置膜是否存在的証據。 <br> Abstract: Theoretical and experimental researches about microfluidics are the bases of dynamic biochip. Because of the high surface-to-volume ratio for small controlled liquid volume (ranged from nanoliter to picoliter), interfacial phenomena and properties play important roles in micro- or nano-scale flows. In this optofluidics research project, we will study optothermal droplet actuation on partially wettable surface. The main driving force is thermocapillary force. The required thermal gradient is generated via optothermal conversion. A thin layer of hydrogenated amorphous or nanocrystalline silicon is deposited on a transparent glass or a plastic substrate as an optothermal conversion material. The wettability of deposited silicon thin film will be altered by surface modifiers. An optical beam focuses on silicon thin film, converting absorbed optical energy into thermal energy, generating thermal gradient to actuate the overlying sitting droplet. The key for the success of this research project is the quality of grafted surface. Quality of grafted surface with surface modifiers will strongly depend on the crystallinity of silicon deposited underneath. We will use different hydrogen dilution during plasma enhanced chemical deposition to control crystallinity of deposited silicon thin film. Using surface analysis tools, such as X-ray photoelectron spectroscopy (XPS), contact angle imaging system, ellipsometry, and atomic force microscopy (AFM), a series of experiments will be conducted to investigate the quality of the grafted surface and its correlation with various crystallinity of deposited silicon thin films. This aims to search the condition of best deposited silicon film for our droplet actuator. The other key issue about droplet motion is the existence of precursor film. It is well accepted that liquid develops a precursor film ahead on solid surfaces before “spreading” on hydrophilic solid surfaces. Precursor film thicknesses were measured to be around a few tens of nanometers. On the other hand, when liquids only partially wet a surface (contact angle 0 o <θ< 90o), there is no solid evidence for the existence of precursor films . We will also use another interrogation laser to explore the existence of precursor film prior to the movement of droplet.微流體光微流體熱毛細力數位微流體液珠運動光熱轉換非晶矽結晶矽OptofluidicsThermocapillaryDigital microfluidicsDroplet motionAmorphous siliconNanocrystalline siliconOptothermal conversion