銀奈米粒子固定於奈米孔洞陣列結構之鎳離子感測應用

Silver Nanoparticle-in-Nanohole Array for Nickel (II) Ion Sensing Application

鄭郁台(Yu-Tai Cheng)

指導教授 ： 游萃蓉

國立清華大學/工學院/材料科學工程學系/碩士(2014年)

摘要

本研究利用奈米球微影術 (nanoshpere lithography) 製作以銀為材料的奈米孔洞陣列 (nanohole array) 結構。同時，利用化學還原合成法製備銀奈米粒子 (silver nanoparticle) ，並在其表面修飾上硫普羅寧 (tiopronin)。接著將銀奈米粒子固定於金屬銀的奈米孔洞陣列，形成新穎的奈米粒子固定於奈米孔洞陣列結構 (nanoparticle-in-nanohole array)。利用新穎的奈米結構，進行試片對於金屬鎳離子 (nickel (II) ion) 的感測；此外，亦透過改變環境介質的折射率，對本研究之新穎奈米結構試片的感測靈敏度 (sensitivity) 進行探討。
本金屬離子感測器的檢測試片 (sensing substrate) 主要由2個部份組成，第一部份為金屬銀奈米孔洞陣列，其製備乃利用帶有正電荷的離子型高分子-聚二烯丙基二甲基氯化銨 (polydiallyldimethylammonium chloride, PDDA) 進行玻璃表面改質，使基板帶有正電荷，接著排列聚苯乙烯 (polystyrene, PS) 奈米球作為微影遮罩，輔以氧電漿 (O2 plasma) 蝕刻聚苯乙烯奈米球，再以電子槍蒸鍍沉積銀金屬後舉離 (lift off) 奈米球遮罩，完成金屬銀奈米孔洞陣列。第二部份為表面修飾硫普羅寧的銀奈米粒子，則由化學還原法合成銀奈米粒子，並於銀奈米粒子表面自組裝硫普羅寧分子，完成具有可與金屬鎳離子進行配位螫合反應能力的表面修飾硫普羅寧銀奈米粒子。接著將修飾硫普羅寧的銀奈米粒子固定於金屬銀奈米孔洞陣列當中，形成新穎的銀奈米子固定於銀奈米孔洞陣列結構。
本研究將修飾硫普羅寧的銀奈米粒子固定於金屬銀奈米孔洞陣列試片，置於鎳離子濃度從1 × 10-4 至 1 mM的環境中，透過紫外光-可見光光譜儀 (UV-Vis) 量測檢測試片的光學吸收度。由實驗結果發現檢測試片之特徵峰強度，隨著鎳離子濃度的上升而增強。此外，本研究亦透過將檢測試片置於空氣、水、乙醇、異丙醇等不同折射率的環境介質中，量測檢測試片的吸收峰位移與環境介質折射率的關係，可得到本研究所製備的金屬鎳離子感測器靈敏度可達21.23 nm/RIU。

關鍵字

銀奈米粒子 ； 奈米孔洞 ； 孔洞陣列 ； 鎳離子

並列摘要

A novel nanostructure with silver nanoparticles assembled in silver nanoholes array was fabricated and developed as a novel metal ion sensor in this work. It has been demonstrated to fabricate nanoholes array by nanosphere lithography (NSL). Silver nanoparticles were synthesized by sodium citrate through the chemical reduction method, and then were surface modified by tiopronin. The tiopronin-modified silver nanoparticles were immobilized into the nanoholes array, so that the sensing substrate with novel nanostructure, nanoparticle-in-nanohole array, was fabricated and used as nickel (II) ion sensing. In addition, the sensitivity of the novel metal ion sensor was characterized under different media with varying refractive indices.
The sensing substrate was composed of 2 components, the nanoholes array and the tiopronin-modified silver nanoparticles (Tio-Ag NPs). The nanohole array was fabricated on glass substrates with surface modification of polydiallyldimethylammonium chloride (PDDA), which is an ionic polymer with positive charge. The NSL was then utilized to arrange polystyrene (PS) mask on the substrates, and PS nanospheres were etched by O2 plasma treatment. Following above, silver was deposited by E-gun and the PS mask was lifted off by common tapes. The Tio-Ag NPs were synthesized through chemical reduction method and followed by the surface modification of tiopronin. Finally, the Tio-Ag NPs were then immobilized into the nanohole array to form a novel nanostructure, nanoparticle-in-nanohole array.
The sensing substrates with nanoparticle-in-nanohole array were placed in nickel ion solution by increasing the concentration from 1 × 10-4 to 1 mM step by step and from 1 × 10-9 to 1 mM step by step, and then characterized by ultraviolet-visible spectroscopy (UV-Vis) at each step. The absorbance enhancement was observed as concentration elevation of nickel ion. The sensitivity was also identified as 21.23 nm/RIU through measuring the absorbance peak shift of the sensing substrates in the media with different refractive indices, such as air, water, ethanol, and isopropyl alcohol (IPA).

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