Inhibiting Condensation Freezing on Patterned Polyelectrolyte Coatings

Condensation freezing inhibition is of great practical importance for anti-icing applications; however, no coatings with this performance have been reported. Here, we report the inhibition of condensation freezing on patterned polyelectrolyte coatings, including polyelectrolyte brush (PB), polyelectrolyte multilayer (PEM), and polyelectrolyte hydrogel (PH) surfaces, benefiting from their feature in regulating ice nucleation and propagation via changing counterions. On the reported surfaces, ice nucleation can be initiated exclusively at the domains with the polyelectrolytes; moreover, spontaneous ice propagation can be achieved atop the patterned polyelectrolyte surface. Consequently, condensed water surrounding the frozen drops on the patterned polyelectrolyte surface evaporates due to the instantaneously released latent heat in the course of ice propagation. Afterward, ice grows specifically on polyelectrolyte surfaces via desublimation as the saturated vapor pressure of ice is smaller than that of condensed water drops. As such, an ice-free region up to 96% of the entire surface area can be accomplished. We demonstrate that various polyelectrolyte coatings can be easily introduced on almost all surfaces, revealing great promise for anti-icing applications.