2.2.4 Polarizing optical microscope (POM)
A
DM2500P
polarizing optical microscope (Leica Microsystems, Wetzlar, Germany)
equipped with a Leica DFC420C digital camera was used for observing the
wax crystal morphology and crystallization behavior of sample fuels. A
drop of samples was putted on a slide, and initially hold at 30 °C for 3
min to eliminate all the crystal memory and subsequently cooled under a
fixed cooling rate (0.8 °C/min) down to −60 °C using the liquid
nitrogen, and the micrographs were captured in 1 °C increments under a
magnification of 100×.