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，已知水及正十六烷(Hexadecane, HD)之液滴在此高表面能的SBSi基材上會展現自發性擴張行為。本研究討論了低蒸氣壓的極性液體在SBSi基材上之潤濕行為，像是二乙二醇單丁醚(Butyl diglycol, BDG)、二甲基甲醯胺(Dimethylformamide, DMF)、二甲基亞碸(Dimethyl sulfoxide, DMSO)等。我們依照液滴在SBSi基材上的行為分為三個類型：部分潤濕、完全潤濕、及非典型潤濕行為。BDG液體屬於部分潤濕行為，在基材上呈現液滴狀且接觸角約為25度。水及HD則屬於完全潤濕之液體，初始接觸角即小於五度，並隨著潤濕面積不斷擴張而持續下降。DMF及DMSO在SBSi基材上也展現自發性擴張行為，但其以不規則形狀向外擴張，且潤濕面積中含有一些孔洞，並能觀察到邊緣較中心厚的情況，造成此類非典型潤濕行為的原因為基材表面水分導致的Marangoni flow。接著將不同性質之液體混合，混合物液滴在SBSi基材仍能表現完全潤濕的擴張行為，並會受部分潤濕液體的影響而縮回，最後，在低遲滯表面的表面張力梯度造成液滴隨機移動。此外，也探討純液滴置於以界面活性劑進行表面物理改質之SBSi基材，進而分析不同濃度變化所造成的液滴行為改變。瞭解液體在固體基材的行為，能應用在工業上的清洗操作及日常生活中的疏水塗層，藉由潤濕現象的理論基礎做為改善應用的依據。

The zwitterionic surface is fabricated by grafting sulfobetaine silane (SBSi) on a glass slide. On the SBSi substrate possessing high surface energy, both water and hexadecane (HD) drops exhibit spontaneous spreading behavior. In this work, the wetting behavior of polar liquids with low volatility, such as butyl diglycol (BDG), dimethylformamide (DMF), and dimethyl sulfoxide (DMSO) on SBSi surfaces were studied. Three types of wetting behavior are identified, (i) partial wetting, (ii) total wetting, and (iii) atypical spreading. BDG liquid belongs to the partial wetting type and forms a drop with low contact angle about 25°. The water and HD drops continuously spreads with circular wetting area, classified as the total wetting type. Although the DMF drop spreads spontaneously on SBSi surfaces, its shape is highly irregular. In addition, the ridge near the rim is developed and dry patches are created by the non-uniform advancement of contact lines. This atypical total wetting behavior is possibly driven by the Marangoni flow. After mixing the liquids of different types, the droplets of the mixture still exhibit spontaneous spreading behavior on the SBSi substrate, and retract under the influence of partially wetting liquids. Finally, on the hysteresis-free SBSi surface random motion of droplets was observed due to surface tension gradients. In addition, intriguing wetting phenomena was observed for pure liquid drops placed on surfactant contaminated SBSi surfaces. Understanding the behavior of liquids on solid substrates can be applied in industrial cleaning operations and hydrophobic coatings in everyday life, and the theoretical basis for wetting phenomena is used as a foundation for improving applications.

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