phase change
When designing icephobic coatings or surfaces, it's critical that researchers have a deep understanding of the phase change of water from liquid to solid (phase change to ice). Part of the nuances of these phase transformation are the quasi liquid layer which refers to a thin layer of water that can form not top of ice and the special attention required to ice nucleation which is the act of an ice particle forming an ice crystal. Especially in instances of icephobic coatings and surfaces that aspire to prevent ice formation, not giving the water a chance at all to phase change, being attentive to the nuances of water phase changes is crucial to a surface's functionality, sustainability, and productivity.
anti-freeze proteins
Some species of fish living in polar climates have anti-freeze proteins (AFPs) that can inhibit the freezing of body fluids, even in temperatures down to -10 degrees celsius. The AFPs have a high affinity for the water-ice front, meaning it has structural match to ice crystals, therefore inhibiting the development of ice. With AFPs, a curved water-ice front forms, depressing the melting point. In icephobic research, AFPs quickly became one of the most studied natural forms.
nucleation
Ice nucleation occurs when ice crystals embryos on nucleation sites often membrane proteins. This results in the water molecules aligning and starting the freezing process. New phases can only be initiated if the free energy barrier for ice formation is overcome (otherwise known as stable conditions for nucleation). In other words, the ice embryo doesn't form until the Gibbs free energy barrier is crossed. Water molecules that touch a concave surface with existing ice crystals are more likely to find those ice crystals and, therefore, freeze. However, when water molecules find a convex surface, they are more likely to remain liquid molecules because they can't travel into surface pockets.