介電泳力應用在連續型加熱流道進行單壁奈米碳管分離之研究

Sortation of Single-Walled Carbon Nanotubes by Using Microelectrodes with Heated Running-Channel

邱振峯(Chen-Fong Chiu)

指導教授 ： 黃榮堂 ； 施勝雄

國立臺北科技大學/機電學院/製造科技研究所/碩士(2007年)

摘要

現今單壁奈米碳管(Single-Walled Carbon Nanotubes ,SWNTs)已被廣泛的使用在奈米級的電子元件或生物、氣體等檢測研究上，其依照電性分成了金屬型與半導體型，而本研究所提出方法；乃是一種可以有效達到量產的分離法；也就是將金屬型與半導體型單壁奈米碳管的技術，其特色為使用微機電製程；(MEMS)製作出指叉式鋸齒狀的微電極，以及使用聚二甲基矽氧烷（polydimethylsiloxane, PDMS）製作連續型流道，並於流道底部加熱產生自然對流；再配合介電泳力(Dielectrophoresis Force)及循環系統進行分離。
首先施加一特定範圍頻率的交流電訊號，使得單壁奈米碳管溶液中的半導體型單壁奈米碳管及金屬型單壁奈米碳管產生極化，依照其極化後的差異性進行分離，金屬型單壁奈米碳管會因為正介電力而吸附在微電極上，反之，半導體型單壁奈米碳管則會因為負介電力被排斥並且懸浮在溶液中，之後將分離後的溶液利用循環系統收集，藉此達到大量生產高濃度半導體型單壁奈米碳管的目的。
分離後的奈米碳管則以拉曼光譜試驗儀(Raman spectroscopy)，檢測單壁奈米碳管之金屬型與半導體型碳管的分布範圍，並藉由光譜圖之強度與位移的變化證明本研究所提出的加熱式分離法，可有效分離出高純度的半導體型碳管。

關鍵字

自然對流 ； 介電泳力

並列摘要

Single-walled carbon nanotubes (SWNTs) have attracted great interests in application of nanoscale electronic devices, bio-sensors and other areas because of their specific and uniform properties. According to the material and geometry properties of single-walled carbon nanotubes there are two modifications as metallic (m-SWNTs) and semiconducting (s-SWNTs).
This research disclosed a new method to sort Single-walled carbon nanotubes (SWNTs). Our method combines the dielectrophoresis with Rayleigh-Benard instability. Dielectrophoresis has been widely used on control or to sort SWNTs depended on the electric field gradient in various fields.
The polarizability of metallic and semiconducting nanotubes is extremely different for dielectrophoresis. Moreover, we also design a unique running channel for moving the SWNTs solution forward to continuously produce sorted SWNTs. Meanwhile a hotplate is employed to heat bottom side of the running channel to cause the free convection flow (Rayleigh-Benard Instability occurs inside a unstable fluid enclosed between two horizontal planes at different temperatures) that could enhance the sorting semiconducting SWNTs with higher concentration. At last, we use the Raman spectroscopy to determine the range of SWNTs.
Therefore, we assure the proposed experimental device could achieve the purpose of mass production of semiconducting SWNTs with higher concentration.

並列關鍵字

Sortation ； Running-Channel ； Dielectrophoresis ； Rayleigh-Benard Instability.

參考文獻

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