Hybrid Surface Designs with Passive Anti-Frosting Capabilities

Controlling the formation of frost is of utmost importance for a multitude of applications – air-to-liquid heat exchangers, aircraft, various types of lenses, among many others. Recently, the role of macrotextures has become increasingly clear to modulate how and when frost forms. However, for anti-frosting surfaces to appeal to a wide range of applications, it is desired for the frost-free region to be a planar geometry. Here, we devise an engineered surface to focus a majority of frost formation on millimetric-sized features, inspired by typical leaf structures, while creating a planar region that is thermodynamically preferred to prevent frost. While experiments have shown that these macro-features can solely create a frost-free zone, that effect can be enhanced through the addition of polymeric materials that possess both vapor adsorption and nucleation-modulating properties. These hybrid materials can effectively modulate the flux profile of water vapor such that the desired regions can stably resist ice nucleation activity over large time scales. As such, the result is the creation of a surface design framework that, through incorporating multiple hybrid components, suggests techniques to create state-of-the-art frost-resistant surfaces.