University of Maryland , College Park, Maryland 20742, United States.
Langmuir. 2018 Jan 16;34(2):585-594. doi: 10.1021/acs.langmuir.7b02900. Epub 2018 Jan 5.
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.
由于其高比表面积，超小金属纳米粒子本质上是不稳定的。本工作研究了如何通过将它们纳入聚合物基质中的即时生长过程来避免这些纳米结构的生长和聚集。我们使用气溶胶单滴反应器方法在聚合物基质中证明了 Ni、Co 和 Cu 纳米粒子的亚 5nm 颗粒的形成。给予气溶胶颗粒的快速热脉冲能够形成核并生长，随后快速淬火以冻结结构。讨论了温度以及所得尺寸和形态的前体浓度的作用。特征时间分析和颗粒尺寸分布的分析得出的结论是，生长受成核和表面生长控制，凝聚或奥斯特瓦尔德熟化很少。最后，我们注意到，这种气溶胶途径适合于用于大规模生产纳米团簇的放大，这些纳米团簇可以根据应用在聚合物中使用或通过溶剂萃取释放。
