Synthesis of gold nanorods (Au NRs) using surfactant-mediated seeded growth involves the interplay of parameters such as pH, reducing agent, and surfactant among others. The use of binary surfactant mixtures of cetyltrimethylammonium bromide (CTAB) and oleic acid (OA) has been reported by our group previously to obtain other anisotropic shapes. However, there are no reports investigating the growth kinetics and mechanisms of such shapes. Here, we report for the first time a ternary representation for compact visualization of shape transitions of gold nanoparticles (Au NPs) as a function of reaction parameters. Further, using UV-Vis spectrophotometry, the growth kinetics of these shapes was tracked using an in-house developed technique. The interplay between the experimental parameters and the properties of Au NPs was investigated using statistical analysis which showed that the reducing agent and pH were significant in influencing shape and growth kinetics. We further propose a growth mechanism in which the supersaturation of growth units controls the final shapes obtained.

中文翻译：

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调谐和跟踪使用二元表面活性剂混合物合成的金纳米粒子的生长

使用表面活性剂介导的种子生长合成金纳米棒 (Au NRs) 涉及 pH、还原剂和表面活性剂等参数的相互作用。我们小组之前已经报道了使用十六烷基三甲基溴化铵（CTAB）和油酸（OA）的二元表面活性剂混合物来获得其他各向异性形状。然而，没有报道调查这种形状的生长动力学和机制。在这里，我们首次报告了作为反应参数函数的金纳米粒子 (Au NPs) 形状转变的紧凑可视化的三元表示。此外，使用紫外-可见分光光度法，使用内部开发的技术跟踪这些形状的生长动力学。使用统计分析研究了实验参数与 Au NPs 特性之间的相互作用，结果表明还原剂和 pH 值对形状和生长动力学有显着影响。我们进一步提出了一种生长机制，其中生长单元的过饱和度控制了获得的最终形状。