Youn Sang Cheon, Jung Dae-Hwan, Ko Young Koan, Jin Yong Wan, Kim Jong Min, Jung Hee-Tae
Department of Chemical and Biomolecular Eng.(BK-21), Korea Advanced Institute of Science and Technology, Daejeon 305-701 Korea.
J Am Chem Soc. 2009 Jan 21;131(2):742-8. doi: 10.1021/ja8073209.
We developed a novel method of vertical alignment of SWNTs using a single-step process for the simultaneous vertical alignment of the SWNTs by a magnetic field and the fixation of their alignment by means of the direct evaporation of the films. We fabricated Fe-oxide/SWNT samples that are reacted by iron-oleate complex, oleic acid and cut SWNTs in 1-octadecene. The Fe-oxide/SWNT samples are dispersed in N,N-dimethylformamide and the resulting solution was deposited on an ITO glass substrate using the spraying method with magnetic field. After evaporation of the SWNT solution in the presence of a magnetic field, we transferred the nanotubes to the vacuum-evaporator chamber, and titanium is evaporated by e-beam evaporation to hold the vertical alignment of the SWNTs. The resulting SWNTs exhibit the formation of a high degree of vertically aligned SNWTs over a large area. We showed that the degree of orientation of the SWNTs is strongly influenced by the field strength, film thickness of the evaporating molecules and evaporating rates. This technique takes significant advantages of the alignment of SWNTs with high aspect ratio at room temperature, without any organic binders and without the need for further alignment procedures. Moreover, this method might be applicable to other anisotropic materials with high aspect ratio.
我们开发了一种新型的单壁碳纳米管垂直排列方法，该方法通过一步法实现单壁碳纳米管在磁场作用下的同时垂直排列，并通过薄膜的直接蒸发来固定其排列。我们制备了由油酸铁络合物、油酸和在1-十八烯中切割的单壁碳纳米管反应而成的氧化铁/单壁碳纳米管样品。将氧化铁/单壁碳纳米管样品分散在N，N-二甲基甲酰胺中，然后使用磁场喷雾法将所得溶液沉积在ITO玻璃基板上。在磁场存在下蒸发单壁碳纳米管溶液后，我们将纳米管转移到真空蒸发室，通过电子束蒸发蒸发钛以保持单壁碳纳米管的垂直排列。所得的单壁碳纳米管在大面积上呈现出高度垂直排列的结构。我们表明，单壁碳纳米管的取向程度受到场强、蒸发分子的膜厚度和蒸发速率的强烈影响。该技术具有在室温下以高纵横比排列单壁碳纳米管的显著优势，无需任何有机粘合剂，也无需进一步的排列程序。此外，该方法可能适用于其他具有高纵横比的各向异性材料。
