- 學位論文
利用電子顯微鏡研究纖維素包覆石墨烯
Investigation of Graphene Shelled Cellulose Fibers Via Electron Microcopy
摘要
利用電子顯微鏡研究纖維素包覆石墨烯 學生：江正輝 指導教授：謝淑惠 博士 國立虎尾科技大學材料科學與綠色能源工程碩士班 摘要 單層石墨烯為一種由C原子以sp2混成軌域組成呈蜂巢狀排列的二維材料，是世界上最薄的材料，其電阻率極低(10-6 Ω•cm)，電子在石墨烯上跑的速度極快(電子遷移率超過15000 cm2/V•s)。因此被期待可用來發展出更薄、導電速度更快的新一代電子元件或電晶體。將石墨烯複合於不導電的纖維上，可讓這些纖維附加了石墨烯的特殊性質，以運用於發展紙電池，或是多功能的纖維等等。 但由於石墨烯在遭受側面方向的擠壓時容易產生皺摺造成團聚現象，導致石墨烯在實際應用上常常遭遇許多製程上的困難。利用氧化方式給予石墨烯一些含氧官能基，使石墨烯部分氧化由疏水性轉為親水性，讓石墨烯能夠均勻展開並分散在水溶液中，且不失去原石墨烯獨特的材料特性，又能大面積地展開被利用。纖維不耐高溫且表面粗造，將石墨烯部分氧化後(稱為部分氧化石墨烯，PGO)滴在親水濾紙上，部分氧化石墨烯緊密包覆纖維，導致包覆石墨烯界面不易觀察。 目前文獻中利用電子顯微鏡探討纖維素包覆石墨烯界面少。因此，本研究首先利用電子顯微鏡觀察氧化石墨烯(GO)展開平鋪於烷化矽晶片的界面，接著探討部分氧化石墨烯/親水纖維(PGO/F)界面。將以改良Hummer’s法製備的GO滴在烷化矽晶片然後進行SEM 及 TEM 顯微分析。研究結果發現使用SEM觀察GO需使用低能量的電子束(E-beam 0.5 KV)觀察最佳，並在TEM作試片截面觀察到GO非常平整展開平鋪於烷化矽晶片上，且其界面並無第三相存在。接著將PGO滴在親水濾紙上，然後抽取單根PGO/F將其黏貼於無碳膜銅網上，並進行SEM 及 TEM 顯微分析，探討PGO/F界面之微觀結構。由於纖維在高能量電子束的照射下產生熱會嚴重變形，增加了分析的困難度。TEM顯微分析提供我們了解PGO在表面粗糙纖維素上包覆機制和界面結合狀況，展開的PGO和親水纖維互相吸引，使得PGO以非常緊密的方式沿著親水纖維表面包覆，而PGO會隨著崎嶇纖維束表面貼合密不可分，且由於PGO彼此間並不會吸引所以纖維外只包覆單一片PGO，多餘的PGO會隨水帶走或堆積於纖維間，觀察過程中也發現PGO隨著纖維因受電子束的熱影響的膨脹會一起變形且不脫落。 關鍵詞：電子顯微鏡、纖維素包覆石墨烯
並列摘要
Investigation of graphene shelled cellulose fibers via Electron Microcopy Student：Jeng-Huei Jiang Advisors：Shu-Huei Hsieh Ph.D. Department of Material Science and Green Energy Engineering National Formosa University Abstract A single layer of Graphene is a two dimension film of honeycomb-like arranged carbon atoms, is the world's thinnest material, owns low resistivity (10-6 Ω•cm) and high electrons transfer(>15000 cm2/V•s). It can be used to develop a thin and highly electric conducting component. Our laboratory had developed an oxidation method to form partially oxidized graphene (PGO). The PGO contains low density of hydrophilic oxygen functional groups that can interact with water molecules making PGO solvable in water while remaining electrically conductive. The PGO solution could be used to deposit the PGO on the cellulose fibers. Because of the cellulose fibers are hydrophilic results PGO forming a continuous layer that completely wraps around the fiber. But the close connect of PGO/fiber makes the interface is difficult to be observed by transmission electron microscope (TEM). There are few reports to investigate the interface between Graphene and fiber by electron microscope. Therefore, this study, we use electron microscopy to observe the interfaces of assembled GO/Si and PGO/fiber. On SEM observation, we found the assembled GO/Si samples are suitable to observe in low-energy electron beam (E-beam 0.5 KV), and the TEM cross-section shows the assembled –GO is unfold and good contact with Si substrate. And the irradiation of high energy density of electron beams on the PGO/Fs gives rise to sudden expansion of the irradiated area which then slowly shrinks back to the normal size. The TEM observations show that PGO completely wraps around the fiber and most of the PGO on the fibers is single layer. Key words：Transmission Electron Microscope, Graphene/Cellulose Fiber