Ortiz Peña Nathaly, Ihiawakrim Dris, Creţu Sorina, Cotin Geoffrey, Kiefer Céline, Begin-Colin Sylvie, Sanchez Clément, Portehault David, Ersen Ovidiu
Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), UMR 7504 CNRS Université de Strasbourg, BP 43 Strasbourg Cedex 2, France.
Université Paris Cité, CNRS, Laboratoire Matériaux et Phénomènes Quantiques, 75013 Paris, France.
Nanoscale. 2022 Aug 4;14(30):10950-10957. doi: 10.1039/d2nr01511k.
We have investigated the early stages of the formation of iron oxide nanoparticles from iron stearate precursors in the presence of sodium stearate in an organic solvent by liquid phase transmission electron microscopy (IL-TEM). Before nucleation, we have evidenced the spontaneous formation of vesicular assemblies made of iron polycation-based precursors sandwiched between stearate layers. Nucleation of iron oxide nanoparticles occurs within the walls of the vesicles, which subsequently collapse upon the consumption of the iron precursors and the growth of the nanoparticles. We then evidenced that fine control of the electron dose, and therefore of the local concentration of reactive iron species in the vicinity of the nuclei, enables controlling crystal growth and selecting the morphology of the resulting iron oxide nanoparticles. Such a direct observation of the nucleation process templated by vesicular assemblies in a hydrophobic organic solvent sheds new light on the formation process of metal oxide nanoparticles and therefore opens ways for the synthesis of inorganic colloidal systems with tunable shape and size.
我们通过液相透射电子显微镜（IL-TEM）研究了在有机溶剂中，硬脂酸钠存在下，由硬脂酸铁前体形成氧化铁纳米颗粒的早期阶段。在成核之前，我们已经证明了由夹在硬脂酸层之间的基于铁多阳离子的前体形成的囊泡组装体的自发形成。氧化铁纳米颗粒的成核发生在囊泡壁内，随后在铁前体消耗和纳米颗粒生长时囊泡壁坍塌。然后我们证明，对电子剂量的精细控制，进而对原子核附近活性铁物种的局部浓度的控制，能够控制晶体生长并选择所得氧化铁纳米颗粒的形态。在疏水有机溶剂中由囊泡组装体模板化的成核过程的这种直接观察，为金属氧化物纳米颗粒的形成过程提供了新的见解，因此为合成具有可调形状和尺寸的无机胶体系统开辟了道路。
