| 摘要: | 本實驗將(N,N-Dimethylaminopropyl)trimethoxysilane和1,3-Propane sultone反應製備出雙離子型磺基甜菜鹼矽烷(Sulfobetaine silane，SBSi)，經水解縮合後將SBSi修飾在玻璃基材上並利用面積和液滴接觸線(contact line)之變化探討液滴於SBSi基材上的潤濕現象。使用之液滴分為兩類，純物質(水和十六烷)與添加非揮發性溶質之溶液(纖維二糖(cellobiose)、聚乙烯醇(poly(vinyl alcohol))、聚乙二醇(poly(ethylene glycol))和奈米氧化石墨粒子(graphite oxide nanoparticle)。水的面積於SBSi基材上不斷擴大，隨後因揮發而變小；十六烷因為是非揮發性溶液，其面積即便超過一小時仍可不斷變大。由純物質之結果顯示，此SBSi表面不僅是超親水表面，在此基材上，純溶液為完全潤濕並展現出自發性擴張的潤濕行為。而將基材放入添加非揮發性溶質的溶液中，氣泡在基材上產生滑動行為，因此添加非揮發性溶質液滴的潤濕行為仍為完全潤濕。然而，在空氣中因為非揮發性溶質的析出，會使液滴釘(pin)於基材上並產生接觸角。利用共軛焦顯微鏡法和球帽公式法分析1 wt%纖維二糖溶液之接觸角，結果為2.1o和2.7o。纖維二糖溶液之濃度由0.01增加至1wt%時，因蒸發速率下降使面積逐漸變大。然而，當濃度再升高後由於溶質析出較快，面積則逐漸變小；聚乙烯醇溶液的濃度由0.01至1wt%，則因濃度增加使溶質析出較快，導致面積下降。當濃度再持續增高，則由於黏度影響顯著而致使面積逐漸下降；與纖維二糖之結果相似，氧化石墨溶液之面積亦隨濃度上升而增加，但其抑制蒸發之效果並不像纖維二糖溶液低濃度時顯著。特別的是，聚乙二醇溶液於基材上不產生pinning，改變液滴形狀，液滴會自行縮回球帽狀，以減少(氣液和液固)接觸面積，於濃度0.01 wt%時，可明顯看出液體先擴張開來，之後縮回球帽形。當液滴形成球帽形，受蒸發不均影響在基材上呈現無特定方向且無遲滯的移動行為，最後才由於濃度過高，溶質析出而停止，此行為模式於各濃度(0.01至10wt%)皆可展現。;In this study, (N,N-Dimethylaminopropyl)trimethoxysilane and 1,3-Propane sultone reacted to form Sulfobetaine silane(SBSi). SBSi is modified on glasses in the process of hydrolysis and condensation. By area and contact line variety to realize wetting behavior on SBSi substrates. Solution is divided into two sections, pure solution (water and hexadecane) and solution adding nonvolatile solute(cellobiose, poly(vinyl alcohol), poly(ethylene glycol), graphite oxide nanoparticle). Water spreads on SBSi substrates, area of water increasing. Then due to evaporation, area of water decreases. Hexadecane is nonvolatile solution. Hexadecane keeps spreading even passing an hour, area of hexadecane increasing. It indicates that SBSi substrates are superhydrophilic surfaces. Dipping solution on it, solution shows spontaneous spreading. Water and hexadecane are total wetting on SBSi substrates. When a SBSi substrate is placed in solution that with nonvolatile solute, bubble moves on substrates. As a result, it’s still total wetting. Nonvolatile solute deposition induces pinning behavior. In cellobiose, poly(vinyl alcohol) and graphite oxide nanoparticle solution experiments all indicate above results. Notably, poly(ethylene glycol)(PEG) solution is a special case. PEG solution doesn’t occur pinning behavior. Therefore, due to unequal evaporation rate, it can move non-directionally on level SBSi substrates. If let PEG solution deform, it can return to hemispherical shape no depending on another force. It shows that PEG solution is no hysteresis on SBSi substrates. |
