石墨烯是一種由單層的碳原子組成的,真正的二維材料。碳原子排列成
六角形結構,像蜂巢般的連接成一個完整的平面。他擁有極特殊的特性讓科
學研究者們驚艷。舉例來說,石墨烯擁有極高的載子遷移率和機械強度,並
且它只吸收 2.7%的光,所以對肉眼來說幾乎是透明的不可見的,這些特性
使它非常適合用以作為保護層。為了達到這樣的應用,石墨烯的表面特性就
顯得非常重要,其中表面濕潤性是最普遍的表面能量測方式,也就是透過測
量水接觸角,了解它本身表面能和水的比較。然而直至目前為止,關於石墨
烯表面水接觸角的研究並沒有一致的結論,極大和極小的水接觸角都曾被實
驗和理論計算得出。在這些研究中,化學氣象沉積製造的石墨烯是最常被用
來量測水接觸角的,然而這種石墨烯不可避免的含有一些缺陷,例如結晶邊
界、皺褶或者破洞,包括成長和轉移過程都可能產生這些缺陷。這些缺陷對
表面接觸角有嚴重的影響,但卻並沒有被完整的討論過。
在本研究中,含有極少缺陷的石墨烯被人為添加了不同種類的缺陷,用
以測量這些缺陷對水接觸角的影響,分別採用結構型的缺陷和化學類的缺陷。
另外,相較於靜態接觸角,動態接觸角含有更多的物理意義,並且對區分不
同缺陷影響有許多幫助,因此在本研究中前進接觸角和退後接觸角皆被量測
並比較,希望能對石墨烯的表面研究有一些貢獻。

Graphene, a real 2-dimension material composed of one layer of carbon atom
with honeycomb-like lattice, impressed scientist by its special properties. For
example, graphene has extremely high carrier mobility and mechanical strength
due to the sp2 structure. Furthermore, graphene only absorbs 2.7% of light and is
almost transparent to eye and hence graphene is appropriate to be a protective
coating layer. To be a protective coating layer, more surface properties of graphene
need to be fully understood. However, scientists have not reached an agreement at
some properties, for example, the wetting property, or water contact angle. In the
past decade, expert groups all around the world have extensively reported both
experimental and theoretical results, which are somehow inconsistent. In these
wettability measurements, CVD graphene was most used because pristine
graphene was too crumbled and rGO had too much oxygen and organic group
remained. However, unavoidable defects, i.e. grain boundaries, wrinkles and holes,
were also created in CVD and transfer process as well. These defects affected
results of contact angle measurement but did not receive much concern because
defect was inevitable in graphene. Fortunately, contact angle hysteresis provides a
remarkable solution.

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