探討在不同離子型界面活性劑中的金奈米棒和啞鈴形金奈米棒銀殼的成長機制，在溴化十六烷基三甲基銨(CTAB)中，利用晶種介質成長法合成金奈米棒，在相同時間，在金奈米棒加入不同莫耳數的四氯金酸和左旋維生素C獲得不同長寬比的啞鈴形金奈米棒，在離子型界面活性劑包含陽離子CTAB、氯化十六烷基三甲基銨(CTAC)和陰離子十二烷基硫酸鈉(SDS)，把金奈米棒和啞鈴形金奈米棒當作模板，合成金銀核殼形奈米棒，金銀核殼形奈米棒的反應過程中，表面電漿共振吸收峰產生藍位移。室溫下，在SDS或CTAB溶液合成金銀核殼形奈米棒形狀像船形，但是在SDS溶液反應速率比CTAB溶液快；另一方面，高溫下，在CTAC或CTAB溶液合成金銀核殼形奈米棒形狀像長方形，並且在CTAC的反應速率快。另外，高溫下CTAC和CTAB溶液中的啞鈴形金銀奈米棒形狀為長方形和雙三角錐。在高溫中的啞鈴形金奈米棒，從UV-Vis發現表面電漿共振吸收峰產生藍位移，得到較小長寬比的金奈米棒。 Mechanism of the growth of silver shells on both the gold nanorods (NRs) and dumbbells (DBs) is studied in ionic surfactant solutions. Gold nanorods were prepared by seed-mediated growth method in the aqueous solution of hexadecyltrimethyl ammonium bromide (CTAB). At the same time, gold dumbbells with different aspect ratios were obtained by the reaction of gold nanorods with HAuCl4 and ascorbic acid. Gold NRs and DBs were then used as the templates to synthesize gold-silver core-shell nanorods (Au@AgNRs) in the ionic surfactant solutions, including cationic CTAB, hexadecyltrimethyl ammonium chloride (CTAC) and anionic sodium dodecyl sulfate (SDS). The surface plasmon resonance band of Au@AgNRs in UV-Vis spectra was blue-shift during the reaction process. Au@AgNRs synthesized in SDS or CTAB solutions have boat shapes at room temperature. But, the reaction rate in the former is faster than in the latter. On the other hand, Au@AgNRs synthesized in CTAC or CTAB solutions have rectangular shape at the higher temperature. And the former has the higher reaction rate. Further, Au@AgDBs synthesized in CTAC or CTAB solutions have rectangular shape and triangular bipyramid at the higher temperature. Furthermore, gold dumbbells are changed to gold nanorods with a lower aspect ratio at high temperature. Blue-shifts of longitudinal plasmon peak correspond to a decrease of the aspect ratio.
