Formation dynamics of gold nanoparticles in poly(vinylpyrrolidone) and other protective agent solutions.
Formation dynamics of gold nanoparticles in poly(vinylpyrrolidone) and other protective agent solutions.
复制标题
聚（乙烯基吡咯烷酮）和其他保护剂溶液中金纳米粒子的形成动力学。
DOI：
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
K. Katayama
中科院分区：
文献类型：
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作者：
Y. Nakazato;K. Taniguchi;S. Ono;Takeshi Eitoku;K. Katayama
利用近场外差瞬变光栅法在微秒到秒级的时间范围内探测到了光还原引发的金纳米颗粒形成动力学过程中涉及的中间化学物种。在动力学过程中发现，金的离子物种(H[Au(I)Cl2]、H[Au(III)Cl4])以及与保护剂聚乙烯吡咯烷酮(PVP)、(H[Au(I)Cl2)-PVP、H[Au(III)Cl4]-PVP形成络合物种的离子物种都参与了这一过程。此外，在PVP浓度大于0.4 mM，HAuCl4浓度为10 mM时，还观察到了另一种化学物种，其扩散系数比其他离子物种小两个数量级。从反应机理和由爱因斯坦-斯托克斯方程估算的组分(3.5 nm)的流体力学直径，我们得出结论，该组分对应于金纳米粒子核。由于核浓度对PVP浓度的依赖关系类似于H[Au(I)Cl2]-PVP和H[Au(III)Cl4]-PVP络合物物种的依赖关系，因此金纳米粒子的成核是通过络合物物种进行的。其他四种保护剂(PVP K15、Triton X-100、Tween20、Brij 58)的反应机理也是如此。此外，我们还对成核的决定因素进行了研究，明确了成核的决定因素是HAuCl4与保护剂之间的分子比，而不是HAuCl4本身的浓度。假设反应为两步反应，这一结果表明反应是由保护剂辅助的初始还原过程控制的，之后核的生长继续进行。
Intermediate chemical species involved in the formation dynamics of gold nanoparticles triggered by photoreduction were detected on the temporal range from microseconds to seconds by the near-field heterodyne transient grating method. In the dynamic processes, it was found that not only the ionic species of gold (H[Au(I)Cl(2)], H[Au(III)Cl(4)]), but also the ionic species that formed complex species with the protective agent poly(vinylpyrrolidone) (PVP), (H[Au(I)Cl(2)]-PVP, H[Au(III)Cl(4)]-PVP), were involved. In addition, another chemical species was observed at PVP concentrations greater than 0.4 mM with the HAuCl(4) concentration of 10 mM; its diffusion coefficient was two orders smaller than those for the other ionic species. From the reaction mechanism and the hydrodynamic diameter for the component (3.5 nm) estimated by the Einstein-Stokes equation, we concluded that this component corresponds to gold nanoparticle nuclei. Since the dependence of the nuclei concentration on the PVP concentration showed a similar dependence as those for the H[Au(I)Cl(2)]-PVP and H[Au(III)Cl(4)]-PVP complex species, nucleation of gold nanoparticles occurred by way of the complex species. This reaction mechanism is true for the other four protecting agents (PVP K15, Triton X-100, Tween 20, Brij 58). Furthermore, we investigated the determining factor for the nucleation, and it was clarified that the determining factor for nuclei formation is the molecular ratio between HAuCl(4) and the protective agent, not the concentration of HAuCl(4) itself. Assuming a 2-step mechanism, this result suggests that the reaction is controlled by an initial reduction process aided by the protective agents, after which growth of the nuclei proceeds.
影响因子：
7.4
作者：
Li, HX;Rothberg, LJ
通讯作者：
Rothberg, LJ