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Substrate Dependence of the Freezing Dynamics of Supercooled Water Films: A High-Speed Optical Microscope Study
journal contribution
posted on 2017-09-18, 00:00 authored by E. Pach, L. Rodriguez, A. VerdaguerThe freezing of supercooled water
films on different substrates
was investigated using a high-speed camera coupled to an optical microscope,
obtaining details of the freezing process not described in the literature
before. We observed the two well known freezing stages (fast dendritic
growth and slow freezing of the water liquid left after the dendritic
growth), but we separated the process into different phenomena that
were studied separately: two-dimensional dendrite growth on the substrate
interface, vertical dendrite growth, formation and evolution of ice
domains, trapping of air bubbles and freezing of the water film surface.
We found all of these processes to be dependent on both the supercooling
temperature and the substrate used. Ice dendrite (or ice front) growth
during the first stage was found to be dependent on thermal properties
of the substrate but could not be unequivocally related to them. Finally,
for low supercooling, a direct relationship was observed between the
morphology of the dendrites formed in the first stage, which depends
on the substrate, and the roughness and the shape of the surface of
the ice, when freezing of the film was completed. This opens the possibility
of using surfaces and coatings to control ice morphology beyond anti-icing
properties.