羧酸基對冠狀醚修飾之金奈米微粒辨識鹼金屬離子的影響及利用液晶原修飾之金奈米微粒與液晶材料掺混之研究

Cooperative Effect of Bifunctionalized Nanoparticles on Recognition: Sensing Alkali Ions by Crown- and Carboxylate-Moieties in Aqueous Media; The mesogenic Behavior of cyanophenyls upon doping Gold Nanoparticles

林孟潔(Meng-Chieh Lin)

指導教授 ： 徐秀福

淡江大學/理學院/化學學系碩士班/碩士(2005年)

https://doi.org/10.6846/TKU.2005.00611

摘要

本論文的研究包含兩個部份，第一個部份是表面含雙官能基金奈米微粒對鹼金屬離子辨識之探討，第二個部份為表面以液晶原修飾之金奈米微粒與液晶材料掺混對液晶性質影響之探討。
第一個部份以兩階段修飾的方式，先在金奈米微粒表面上修飾一層thioctic acid (TA)，再分別置換具不同烷鏈長度的皇冠醚硫醇分子。表面修飾有15冠5醚與12冠4醚金奈米微粒分別與鉀離子與鈉離子產生2：1的錯合，而使金奈米微粒溶液的顏色由紅變藍。當表面上的皇冠醚硫醇分子烷鏈長度為四個碳時，因為與TA的長度接近，產生靜電作用力而提升皇冠醚的辨識能力。最後應用在真實尿液中，利用紫外-可見光光譜分析出尿液中鉀離子與鈉離子的濃度，與ICP-AES測量出來的濃度相符合。
第二部份為將氰聯苯系列的液晶材料，與修飾有液晶分子的金奈米微粒掺混。分子間的排列方式隨掺混金奈米微粒量比例的上升而不同，使液晶形成溫度變化越大。由偏光顯微鏡下觀察發現掺混後的液晶分子液晶紋理圖有些微的改變，因此巨觀下已可觀查到掺混對液晶分子的排列造成影響。

關鍵字

雙官能基金奈米微粒 ； 辨識 ； 摻混 ； 定量測定 ； 氰聯苯液晶分子

並列摘要

In the first part, gold nanoparticles with surface modification of bifuncionalities, thioctic acid (TA) and crown ether, were prepared for studies of alkali metal ion sensing. The sensing ability of the GNPs toward K+ and Na+ can be realized by color changes, from red to blue, upon adding metal ions. Such transform is triggered by a 2-to-1 sandwich complexation of 15-crown-5 to K+ and 12-crown-4 to Na+. The alkyl linkage is also found to influence the sensing efficiency. Crown-CH2O(CH2)4S-GNPs showed significantly higher complexation rates than those with longer alkyl linkages. This is possibly due to the cooperative effect that the similar of TA and butyl group pre-organized crown moieties. This method is applied to the qualitative determination of K+ and Na+ in human urine samples by UV-vis spectrometry, and the results are in good agreement with those obtained from ICP-AES.
In the second part, a series of cyanobiphenyl liquid crystals are doped with GNPs covered with liquid crystals. The changes in transition temperatures decrease with increasing doping ratios. By careful examination of the optical textures under polarized optical microscope, differences can be observed before and after doping. The differences in textures are attributed to the change in intermolecular packings upon doing.

並列關鍵字

bifunctionalized nanoparticles ； recognition ； doping ratios ； qualitative determination ； cyanobiphenyl liquid crystals

參考文獻

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