In a recent investigation, scientists found that modifying the texture of surfaces and applying a thin coating of graphene oxide can completely eliminate frost formation on those surfaces for at least one week, potentially even longer. This breakthrough extends the frost prevention duration by 1,000 times compared to the best current anti-frost surfaces.
In the future, individuals may no longer need to defrost freezers or clear ice off slippery surfaces. Engineers at Northwestern University have devised a novel technique that stops frost from forming right from the outset.
In this innovative study, researchers revealed that altering the texture on any surface and adding a thin layer of graphene oxide can prevent all frost from developing for at least a week—or possibly longer. This achievement is 1,000 times more effective than the most advanced anti-frost surfaces available today.
Additionally, this new scalable surface design is durable against cracks, scratches, and pollution.
By integrating this textured design into infrastructure, the researchers envision that companies and government entities could save billions annually by minimizing maintenance expenses and improving energy efficiency.
The findings will be published on Wednesday (Oct. 30) in the journal Science Advances.
“Frost accumulation is a significant issue in industrial, residential, and governmental contexts,” mentioned Kyoo-Chul Kenneth Park from Northwestern University, who led the study. “For instance, the 2021 power crisis in Texas resulted in $195 billion in damages due to frost, ice, and severe cold conditions lasting over 160 hours. Therefore, developing effective anti-frost strategies that endure extreme environments for extended periods is essential. Our hybrid anti-frosting method is designed to meet these needs efficiently, offering weeks of protection and being scalable and easy to create through 3D printing.”
Park holds a position as an assistant professor of mechanical engineering at Northwestern’s McCormick School of Engineering and is affiliated with the Paula M. Trienens Institute for Sustainability and Energy as well as the International Institute for Nanotechnology.
Leaf-inspired discovery
This new research builds on earlier work from Park’s lab. In 2020, Park and his team found that applying textures at the millimeter-scale on surfaces could potentially cut down frost formation by up to 80%. This research, published in the Proceedings of the National Academy of Sciences, was inspired by the structure of leaves.
“Frost tends to accumulate more on the convex parts of a leaf,” Park remarked back then. “Conversely, the concave areas (the veins) have much less frost. This observation has been noted for centuries without a clear explanation for these patterns. We discovered that it is actually the geometry, not the material, that determines this effect.”
Through experimental and simulation studies, Park and his collaborators identified that condensation is intensified on the peaks and diminished in the valleys of wavy surfaces. The minimal water that condenses in the valleys eventually evaporates, leading to frost-free zones.
Graphene-oxide trapping power
In their previous study, Park’s team crafted a surface with millimeter-sized peaks and valleys at slight angles. In this latest research, they applied graphene oxide to the flat valleys, achieving a complete prevention of frost in those areas. The new design consists of tiny bumps with a distance of 5 millimeters between peaks, coated with a thin layer of graphene oxide, just 600 microns thick, across the valleys.
“Graphene oxide has the ability to draw in water vapor and trap water molecules within its structure,” Park explained. “Thus, this layer functions like a container to obstruct water vapor from freezing. When we combined graphene oxide with the macrotextured surface, it successfully resisted frost for extended periods even under high levels of supersaturation. This hybrid surface establishes a stable, frost-free environment.”
When compared to other leading anti-frosting surfaces, Park’s method clearly outperformed. While superhydrophobic (water-repellent) and lubricant-infused surfaces only resisted 5-36% of frost for a maximum of 5 hours, Park’s technique achieved a full 100% resistance to frost for up to 160 hours.
“Most anti-frost surfaces are vulnerable to wear from scratches or impurities, impacting their performance over time,” Park stated. “However, our anti-frost mechanism exhibits resilience against scratches, cracks, and contaminants, prolonging the surface’s lifespan.”
Why it matters
This innovative combination of macrotexture and graphene oxide presents an exciting approach to combating frost formation across various applications. Individuals usually only think about frost when it affects their car windows or threatens their outdoor plants. Yet frost can pose more serious problems.
Frost on airplane wings can increase drag, potentially making flights hazardous or unfeasible. When frost builds up in freezers and refrigerators, it severely impacts their energy efficiency. Additionally, frost can add weight to power lines, leading to breakage and, consequently, power outages. It can also interfere with vehicle sensors, compromising their ability to detect objects accurately.
“Creating new techniques to counter frost is essential to avoid expensive mechanical failures, energy losses, and safety risks in critical operations,” Park indicated. “Currently, there isn’t a universal solution since each application has its unique requirements. For instance, airplanes may only need resistance to frost for seconds, while power lines in cold climates might need frost protection for days or weeks. Our new findings could allow for the design of power lines and airplane wings with reduced ice attachment, significantly lowering annual maintenance costs.”
The study titled “Robust hybrid diffusion control for long-term scalable frost prevention” received partial support from the National Science Foundation (grant number CBET-2337118) and the Korea Institute for Science and Technology (grant number 2E32527).
