Tem cm100 microscope

Silica/hematite
core/shell ellipsoidal particles of two different aspect ratios were
synthesized. Hematite ellipsoids were initially synthesized in water
following the approach described by Ocana et al.^{46 (link)} They were then coated with silica layer(s) in ethanol using
the method described by Graf et al.^{47 (link)} The
aspect ratio of the particles was controlled by tuning the thickness
of the silica shell. Particles were purified by repeated centrifugation/redispersion
cycles in water and were kept in water as a stock dispersion. Details
of the synthesis and characterization of similar particles can be
found elsewhere.^{38 (link)}A transmission
electron microscope (TEM) (TEM-CM100 microscope from Philips operating
at 100 keV) was used to characterize both the size and shape of the
particles. Particle size distributions were calculated by measuring
at least 100 particles from TEM micrographs using the software ImageJ.
For the batch of particles that we have named E1,
we find the long and short axes to be L₁ = 316 ± 26.3 nm and D₁ = 108 ±
7 nm respectively, leading to an aspect ratio of ρ₁ = 2.9, while for another batch, named E2, L₂ = 266 ± 19 nm and D₂ = 72 ± 6 nm, corresponding to ρ₂ =
3.69. Figure 1a,b shows
representative TEM images for the ellipsoids.