Frost—a fluffy member of the ice family that forms when water vapor freezes to a surface—may seem innocuous to many people. But scientists have worked for years to design surfaces that limit its deposition on important infrastructure. Topology and chemistry will affect frost deposition, and researchers in Kyoo-Chul Kenneth Park’s lab at Northwestern University have taken advantage of both to create a frost-resistant surface (Sci. Adv. 2024, DOI: 10.1126/sciadv.adq8525).
In cold, humid conditions, frost formation is thermodynamically inevitable, Park says. Instead of fighting nature, he designed a 3D-printed a honeycomb-like surface texture of thin, micrometer-tall walls to “selectively form the frost.” Because gaseous water molecules diffuse more strongly toward a peak than a valley, Park’s surface forces frost accumulation along the ridges of each hexagonal cell while keeping the cell’s deeper centers dry.
Park found that adding a water-absorbing graphene oxide putty to the bottom of each cell allowed him to prevent frost formation for nearly a week at –12 °C—far longer than other previously published surfaces. Importantly, scratching the graphene oxide doesn’t change this ability. Manufacturing the material in lab is easy, he says. “We are basically playing with Play-Doh and Lego blocks.”
Adding graphene oxide to a textured surface to prevent frost is like adding peanut butter to chocolate to make an even-tastier treat, says Jonathan Boreyko, a mechanical engineer at Virginia Tech who was not involved in the work. Both he and Park have shown in the past that frost preferentially forms at the elevated portions of a structure, while the low parts “have this nice dry zone that can persist for hours,” Boreyko says. That this new approach keeps that lower area dry for so long is impressive and exciting, he says. But he adds that more research and development will be needed to make this antifrost material commercially viable.
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