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Title: | 奈米流體內離子與奈米粒子的電動傳輸:基礎研究與應用 Electrokinetic Ion and Nanoparticle Transport in Nanofluidics: Fundamental Studies and Applications |
Authors: | Chih-Yuan Lin 林志原 |
Advisor: | 徐治平(Jyh-Ping Hsu) |
Keyword: | 奈米流體,離子傳輸,離子整流效應,阻抗脈衝偵測,電動力學現象,聚電解質, Nanofluidic,Ion transport,Bipolar nanopore,Ion current rectification,Resistive-pulse sensing,Electrokinetic phenomena,Polyelectrolyte, |
Publication Year : | 2018 |
Degree: | 博士 |
Abstract: | 奈米流體裝置已成為很有前景的工具用來調節奈米粒子的傳輸、偵測單分子以及整流離子電流。本篇論文完整地探討了雙極性奈米孔道內的離子傳輸行為以及粒子在離子痕跡圓柱形奈米孔道內的輸送現象。我們發現由於不對稱的電荷密度,雙極性奈米孔道展現非常明顯的離子電流整流行為。對雙極性聚電解質刷改質的奈米孔道來說,整流程度隨著鹽濃度提高而降低,並且在聚電解質刷電荷不對稱分布的情況下,隨著電荷的變化而呈現極大值。並且,當施加一鹽濃度梯度在固態雙極性奈米孔道時,離子電流整流的反轉行為將可以被觀察到。我們的模型也證明了,藉由孔道口局部電場的調控,可以達到控制奈米粒子傳輸的效果。此外,我們也針對阻抗脈衝偵測的基礎機制,同時進行實驗及理論的探討。我們發現高度帶電的粒子會比同體積的中性粒子造成更大的電流阻障,這與傳統的想法相違背。這個實驗的發現與理論模型有極佳的吻合,並且可以解釋為高帶電粒子所引起的濃度極化會導致管內嚴重的離子耗盡,從而降低了離子電流。離子電流對脈衝形狀的重要性也在此論文呈現。我們的結果為奈米流體內離子與粒子的傳輸現象提供了更好的瞭解,也為設計相關的裝置提供了有價值的資訊。 Nanofluidic devices have emerged as promising tools for regulating the transport of nanoparticles, sensing single molecules, and rectifying ionic current. This study thoroughly investigates the ion transport behavior in bipolar nanopores and the particle transport phenomenon in ion-tracked cylindrical nanopores. We find that, due to the asymmetric charge density, bipolar nanopores exhibit a pronounced ionic current rectification (ICR) behavior. For the nanopores functionalized with bipolar polyelectrolyte (PE) brushes, the degree of the ICR decreases with increasing bulk salt concentration, and exhibits a local maximum as charge density varies if the PE brushes are asymmetrically distributed. Furthermore, the inversion of ICR behavior can be observed if applying a salt gradient across the solid-state bipolar nanopores. Our modeling also demonstrates that the controlling of the nanoparticle translocation can be achieved by the modulation of the local electric field at the nanopore opening. In addition, the fundamental mechanism of resistive pulse sensing is both experimentally and theoretically investigated. We find that highly charged particle can cause a larger current blockage compared to the neutral particle with same volume, which is against the conventional thought. This experimental finding is in excellent agreement with our theoretical result and can be explained by that the concentration polarization induced by the highly charged particle leads to a significant ion depletion inside the pore, thereby decreasing the ionic current. The importance of the ionic convection on the pulse shape is also presented. Our results provide a better understanding of the transport of ion and particle in nanofluidics, giving valuable information for designing relevant devices. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/69448 |
DOI: | 10.6342/NTU201801287 |
Fulltext Rights: | 有償授權 |
Appears in Collections: | 化學工程學系 |
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ntu-107-1.pdf Restricted Access | 10.97 MB | Adobe PDF |
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