Ultrasmall metal nanoparticles are inherently unstable because of their high specific surface area. This work investigates how growth and aggregation of these nanostructures can be circumvented by incorporating them into a polymer matrix in an on-the-fly growth process. We demonstrate the formation of sub-5 nm particles of Ni, Co, and Cu nanoparticles in a polymer matrix using an aerosol single-drop reactor approach. The rapid thermal pulse given to the aerosol particles enables the formation of nuclei and growth, with subsequent rapid quenching to freeze in the structure. The role of the temperature as well as the precursor concentration of the resulting size and morphology is discussed. A characteristic time analysis and an analysis of the particle size distributions lead to the conclusion that growth is governed by nucleation and surface growth, with little coagulation or Ostwald ripening. Finally, we note that this aerosol route is amenable to scale-up for large-scale production of nanoclusters that can either be used as is within the polymer or released by solvent extraction, depending on the application.

中文翻译：

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亚5 nm金属纳米团簇在聚合物熔体气溶胶液滴中的生长

超小金属纳米粒子因其高比表面积而固有地不稳定。这项工作研究了如何通过在动态生长过程中将它们掺入聚合物基质来避免这些纳米结构的生长和聚集。我们演示了使用气溶胶单滴反应器方法在聚合物基体中形成5nm以下的Ni，Co和Cu纳米颗粒。给予气溶胶颗粒的快速热脉冲使得能够形成核并生长，随后进行快速淬火以冻结在结构中。讨论了温度的作用以及所得大小和形态的前体浓度。特征时间分析和粒度分布分析得出的结论是，生长受成核作用和表面生长的支配，几乎没有凝结或奥斯特瓦尔德（Ostwald）成熟。最后，我们注意到，这种气雾剂路线适合大规模生产纳米团簇，这些纳米团簇可以直接在聚合物中使用，也可以通过溶剂萃取释放，具体取决于应用。