Gold nanorods are prepared in aqueous solution by an electrochemical method and are shape controlled using capping micelles as described by Yu et al. (J. Phys. Chem. B 1997, 101 (34), 6661). Transmission electron microscopic (TEM) images are determined for these gold nanorods, taken from solutions heated that various temperatures in the range of 25-160℃. Size and shape analysis of their TEM images showed that the mean aspect ratio of the nanorods in solution decreases with increasing temperature, mostly as a result of reduction in their length. Heating the dried nanorods themselves on a TEM slide to much higher temperatures does not produce any shape changes. This suggests that the observed relative instability of the longer nan0r in the micellar solutions is attributed to the relative instability of the micelles capping the longer gold nanorods Following the change with time of the longitudinal surface plasmon absorption band of the gold nanorods five different temperatures, the activation energy for the thermal decomposition of the micelles is found to be 21.0 ±1.0 K cal mol↑(-1). The most stable rod-shaped micelle is found to have an aspect ratio of 2.0. The craft decomposition (dissolution) temperature of these micelles is found to be～155 ℃. This study offers a new method in which the thermal stability of micelles of various shapes is used to change the size distribution of metal nanorods in solution. On the other hand, TEM or the absorption maximum of the longitudinal plasmon resonance of gold nanorods can be used as a sensitive monitor in studying the physical properties of the host micelles themselves.
展开▼
机译：金纳米棒是通过电化学方法在水溶液中制备的，并使用封端胶束控制形状，如Yu等人（2002年）所述。 （J.Phys.Chem.B 1997，101（34），6661）。确定了这些金纳米棒的透射电子显微镜（TEM）图像，这些图像取自加热至25-160℃范围内的各种温度的溶液。 TEM图像的大小和形状分析表明，溶液中纳米棒的平均长径比随温度的升高而降低，这主要是由于纳米棒长度的减少。将干燥的纳米棒本身在TEM载玻片上加热到更高的温度不会产生任何形状变化。这表明在胶束溶液中观察到的较长nan0r的相对不稳定性归因于在较长的五个不同温度下金纳米棒的纵向表面等离激元吸收带随时间变化后，覆盖较长金纳米棒的胶束的相对不稳定性。胶束热分解的活化能为21.0±1.0 K cal mol↑（-1）。发现最稳定的棒状胶束的长径比为2.0。发现这些胶束的工艺分解（溶解）温度为〜155℃。这项研究提供了一种新方法，其中使用各种形状的胶束的热稳定性来改变溶液中金属纳米棒的尺寸分布。另一方面，TEM或金纳米棒的纵向等离振子共振的吸收最大值可以用作研究宿主胶束本身的物理性质的灵敏监测器。
展开▼
