本實驗將磺基甜菜鹼矽烷(Sulfobetaine silane, SBSi)經水解縮合修飾至玻璃上而成一雙離子型表面。水滴在此基材上其接觸線會不斷向外擴張，呈現完全潤濕的行為。但若在水中添加微量的溶質時(小分子及高分子)，將會發生自釘扎現象，而使完全潤濕現象消失。此時，液滴的接觸線停止向外擴展並呈現ㄧ較低的接觸角。然而，此自釘扎現象在受重力驅動後將會失效，將含溶質之液滴置於傾斜的SBSi表面上並觀察在重力驅動下液滴的運動行為，可以發現對於大部分的溶質如鹽或高分子，在傾斜角約為5o時，5 l液滴的下端接觸線就會開始向下方滑移，且其尾端會立刻有溶質析出。利用紫外光光譜儀監控滑過表面後液滴的濃度變化，顯示液滴的濃度快速增加，可應用於增濃的相關領域。特別的是，當溶質的分子結構中含有環氧乙烷(Ethylene oxide, EO) 官能基時，如二乙二醇單丁醚(Diethyleneglycolmonobutylether ,BDG)與聚乙二醇(Polyethylene glycol, PEG)，液滴在SBSi 表面上會呈現接近無接觸角遲滯的特殊行為，即便於水平表面上，液滴亦會進行不規則的隨機運動，其原因可歸咎於液滴表面不均勻的蒸發所致。此外，在傾斜角僅1o的傾斜表面上，5 l液滴即會向下滑動，過程中液滴形狀保持約略圓形且不會有溶質析出。並且觀察液滴滑動速度與表面傾斜角之關係，可以發現其運動速度與傾斜角度呈線性關係，再次驗證其近乎不存在的接觸角遲滯，並具有於潤滑相關領域的發展潛力。

The zwitterionic surface is fabricated by grafting sulfobetaine silane (SBSi) on a glass slide. The contact line of a water drop on the SBSi surface spreads continuously, corresponding to total wetting. The addition of 1wt% solutes such as salt or polymer leads to self-pinning of a water drop with small contact angles. The self-pinning behavior will disappear when the SBSi surface is tilted at 5o. Typically, the contact line at the lower-side of the drop with the volume 5 l moves downward. During the gravity-driven spreading, the solutes in the solid state soon appear in the trail of the drop. Using Ultraviolet Spectrometer(UV-Vis) to monitor changes in concentration of the droplets, showing a rapid increase in the concentration of droplets. It can be used for concentrated applications. However, when the solutes possess ethylene oxide (EO) groups such as diethyleneglycolmonobutylether and polyethyleneglycol, the drop on the SBSi surfaces exhibits a hysteresis-free behavior. The drop can move freely on the SBSi surfaces because of the uneven evaporation. In addition, it can slide easily even though the tilted angle is just 1o. During the drop sliding, the shape of the droplet retains approximately circular and there is no solute residue. The velocity of droplets and tilted angles are in linear correlation. Verifying that there is almost no contact angle hysteresis again. Our experimental results reveal that the SBSi surface may be used for lubrication applications.

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