Multichroic Behaviors of Polygonal Gold Nanoparticles

• Main Authors: Chia-Hao Chang, 張家豪
• Other Authors: 侯劭毅
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/b8fs6m

碩士 === 國立臺北科技大學 === 化學工程研究所 === 101 === Most investigations on the color of gold nanoparticle discuss the variations in color due to the size differences of a particle. One example is the Lycurgus cup which is red in transmitted light and turns green under reflected light. This phenomenon is called dichroic color. In this study, we bound gold nanoparticles with carboxyl group and add N-(3-Dimethylaminopropyl)-N''-ethylcarbodiimide hydrochloride (EDC) and N-Hydroxysuccinimide (NHS). To enhance the binding of the carboxyl group with another carboxyl group to create a multi-core. We then reduce the HAuCl4 on this multi-core. The final product obtained by this process exhibits the phenomenon of multichroic color. It is violet-blue in transmitted light, appears orange in reflected light, and tarns pink when placed against a white background (combining reflected light with transmitted light). We used single angle of dynamic static light scattering, transmission electron microscopy and scanning electron microscopy to measure the size and the shape of the particle, and find the shape is polygon, so we call it’s ‘Polygonal Gold Nanoparticles’ . In general, when sodium chloride is added to spherical or oval gold nanoparticles, there will be aggregation. The color of the gold nanoparticle solution will change from burgundy red to purple. However, in this study, when we added sodium citrate to polygonal gold nanoparticles, during the crystals growing phase, they will cause the color of the solution to change from orange to blue and the multichroic color phenomenon will then disappear. We also examined the effect of silica nanoparticles on the polygonal gold nanoparticles and found that the concentration of the silica nanoparticles has a significant effect on the color of the solution, which changes from orange to pink.