一、奈米金結構之合成、官能基化與組裝 二、水相加熱法合成三角與六角金奈米片狀結構之成長機制研究

I. Synthesis of Gold Nanostructures and Their Surface Functionalization and Assembly II. Time-Resolved Investigation of the Growth Process of Triangular and Hexagonal Gold Nanoplates Formed by Thermal Aqueous Solution Approach.

黃婉玲(Wan-Ling Huang)

指導教授 ： 黃暄益

國立清華大學/理學院/化學系/碩士(2006年)

https://doi.org/10.6843/NTHU.2006.00345

摘要

本篇論文包含兩個不同的研究主題，第一個部份有關於金奈米粒子之應用並提供一個金奈米粒子間可逆連結的方法，第二部份則探討金離子如何成長為三角或六角形片狀產物。

酯化鍵的生成與斷裂是本篇研究第一部分的主要對象。硫醇官能基在金奈米粒子的修飾有很好的效果，利用帶有硫醇官能基之tioctic acid (TA) 與11-mercapto-1-undecanol (11-MUDO) 分子修飾在金奈米粒子上，並使TA上之羧基和11-MUDO上之羥基脫水生成酯化鍵，濃硫酸則是反應中的催化劑，而氫氧化鈉則可促使系統進行逆反應。臨場紫外—可見光光譜可以偵測反應中的光譜變化，紅外光譜提供化學鍵生成與斷裂的資訊，而金奈米粒子的型態變化則可在穿透式電子顯微鏡下觀察。

加入濃硫酸後膠體溶液發生聚集的現象，加入氫氧化鈉後溶液還原，達到可逆連結的目的。但在本研究中由於紅外光譜樣品製備過程中產生問題，因此無法確認酯化鍵的是否生成。經過翻查許多參考文獻，造成此聚集與再分散現象的可信原因是溶液中酸鹼值及電解質濃度變化所致。

本篇論文第二部份報導水相加熱合成三角與六角形金奈米片狀物之生長過程，此生長過程主要在穿透式電子顯微鏡下觀察不同時間之產物。我們排除了目前科學家們提出的可能性，包括高分子或介面活性劑對三角形晶種的特定吸附以及大片三角及六角形為小片三角形拼湊而得的假設。根據研究結果，我們推論在成長之初，許多很小的結晶性奈米粒子形成，互相結集並經由再結晶長成三角、六角片狀或球形粒子，而這些金奈米結構也是經由這樣的過程而繼續長成更大之結構，非經由小片完整之片狀物互相融合而成。

關鍵字

金奈米粒子 ； 表面修飾 ； 連結

並列摘要

This thesis included two different topics of research. The first part was about the application of gold nanoparticles and provided a system of reversible linkage between gold nanoparticles. The second part discussed how gold chloride ions grew into triangular and hexagonal gold nanoplates.

Thiol groups were good to be used in functionalizing gold nanoparticles, and ester bond formation and breakage played the major role in this research. Thioctic acid and 11-mercapto-1-undecanol were used to functionalize the gold nanoparticles and form ester bond by using the carboxylic acid group on thioctic acid and the hydroxyl group on 11-mercapto-1-undecanol. Concentrated sulfuric acid was used to be the catalyst in this reaction, and sodium hydroxide was added for the proceeding of the reverse reaction. In-situ UV–vis spectra were taken to monitor the spectral changes during the reaction. IR spectra were obtained to determine the bond formation and breakage. The morphologies examinations were observed from TEM images.

Aggregations took place after the addition of concentrated sulfuric acid and also deaggregation after the addition of sodium hydroxide solution. But in this research, ester bond formation was not confirmed due to the problems occurred in the IR sample preparation. Through many references, the changes in pH and concentrations of electrolytes were more convincing reasons to the aggregation and deaggregation.

The second portion reported a new observation in the growth process of triangular and hexagonal gold nanoplates prepared by a thermal aqueous approach. The growth process was studied through TEM images at different periods of time. We expelled the possibility of preferred adsorption of polymers or surfactants on triangular seeds and the probability for small plates fused to form larger ones which were pronounced by the other groups. We believed that small crystalline seed particles were formed initially, gathered and recrystallized to form triangular, hexagonal nanoplates, or large spherical nanoparticles through Ostwald ripening. Neither of them came from complete grown triangular nanoplates. The gold nanostructures grew in size also by this growth process.

參考文獻

Chapter 1

Introduction to Gold Nanostructures

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