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

Abstract

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.