Influence of Ligand鈥揚recursor Molar Ratio on the Size Evolution of Modifiable Iron Oxide Nanoparticles
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- 作者：Bin Qi ; Longfei Ye ; Roland Stone ; Cindi Dennis ; Thomas M. Crawford ; O. Thompson Mefford
- 刊名：The Journal of Physical Chemistry C
- 出版年：2013
- 出版时间：March 14, 2013
- 年：2013
- 卷：117
- 期：10
- 页码：5429-5435
- 全文大小：451K
- 年卷期：v.117,no.10(March 14, 2013)
- ISSN：1932-7455
文摘
During the synthesis of nanoparticles via thermal decomposition of iron precursors, the capping ligand鈥損recursor ratio influences the resulting size of the iron oxide nanoparticles. As the molar ratio of aliphatic amines to iron precursor is increased, the average diameter of the synthesized iron oxide nanoparticles decreases. This trend is opposite to previously reported results. We investigated this phenomenon by independently varying the ligand chain length, the ligand鈥損recursor molar ratio, and the degree of saturation of the aliphatic chain. Nuclear magnetic resonance spectra of the precursor illustrated the presence of a primary amine peak before heating and the peak absence after heating, potentially indicating that the primary amine acts as reducing agent to promote the decomposition of the iron precursor. We hypothesize that the amine groups play a dominant role in the nucleation of the particles, while the chain length and degree of aliphatic saturation have only a minor effect on particle size. The nanoparticles鈥?size and crystallinity were characterized with high-resolution transmission electron microscopy, dynamic light scattering, and X-ray diffraction, and the magnetic properties were characterized by magnetometry.