1 research outputs found
Influence of Ligand–Precursor Molar Ratio on the Size Evolution of Modifiable Iron Oxide Nanoparticles
During the synthesis of nanoparticles
via thermal decomposition
of iron precursors, the capping ligand–precursor 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–precursor
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’
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