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標題: | 錐狀奈米孔道內離子種類及聚電解質改質表面對離子傳輸行為之影響 Ion Transport Properties in Conical Nanopores: Effect of Type of Salts and Polyelectrolyte Brushes Functionalized Surface |
作者: | Shu-Tuan Yang 楊淑端 |
指導教授: | 徐治平 |
關鍵字: | 圓錐狀奈米孔道,離子電流整流效應,電滲透流,離子種類,電荷可調節之聚電解質層,電雙層, conical nanopore,ion current rectification,electroosmotic flow,type of salts,pH-tunable polyelectrolyte brushes,electric double layer, |
出版年 : | 2017 |
學位: | 碩士 |
摘要: | 圓錐奈米孔道有不對稱的幾何形狀,加上若孔道開口與電雙層厚度相當時,會引起許多特別的電動力學現象,像是離子電流整流效應(ICR)。首先我們考慮不同電解質溶液LiCl、NaCl、KCl,並研究電滲透流(EOF)對整流效應的影響。我們發現有無考慮電滲透流對整流效應係數(Rf)的程度有很大的影響。如果沒有考慮電滲透流,LiCl水溶液在不同外加電壓下的整流效果是三者中最好的。若考慮電滲透流,則不同溶液的整流效果與外加電壓大小相關。
接著,我們討論一合成圓錐狀奈米孔道,其表面塗佈一層pH可調節之聚電解質。考慮在外加電場下,溶液酸鹼值pH、溶液鹽濃度、施加電壓不同對離子傳輸行為及離子選擇性之影響。我們發現溶液導電度會因pH、溶液鹽濃度不同有很大的影響,而離子選擇性則同時受pH、溶液鹽濃度及施加電壓的影響。 The influence of electroosmotic flow (EOF) on the behavior of the ionic current rectification (ICR) in a conical nanopore connecting two large identical reservoirs is investigated. In particular, the effect of the type of salt is examined by considering LiCl, NaCl, and KCl. We show that neglecting EOF is capable of influencing ICR both quantitatively and qualitatively. If EOF is neglected, the rectification factor at each level of the applied electric potential bias across the two reservoirs for the case of LiCl (KCl) is always the largest (smallest). However, if EOF is taken into account, the relative magnitude of the rectification factors for various salts depends upon the level of the applied electric potential bias. This behavior is consistent with the experimental observation in the literature and can be explained by the degree of ion enrichment / depletion in a nanopore. Furthermore, the behaviors of the nanopore conductance and ion selectivity of a conical nanopore surface modified by a polyelectrolyte (PE) layer are studied by adjusting the pH, the bulk salt concentration, and the level of an applied potential bias, and the underlying mechanisms investigated in detail. We show that the conductance is sensitive to the variation in the solution pH, and the conical nanopore has ion current rectification (ICR) behavior. The ion selectivity of the nanopore is influenced significantly by both the solution pH and the level of the applied potential bias. We show that the transport behavior of ions can be tuned easily by adjusting the level of pH, salt concentration, and applied potential bias, thereby providing useful information for future designing of conical nanopores. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/2433 |
DOI: | 10.6342/NTU201701156 |
全文授權: | 同意授權(全球公開) |
顯示於系所單位: | 化學工程學系 |
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