Engineers develop method of preventing frost formation

In their study, the researchers found that modifying the texture of any surface and adding a thin layer of graphene oxide prevents 100 per cent of frost from forming on surfaces for one week or potentially longer.

The new scalable surface design - which is said to be resistant to cracks, scratches and contamination - could be incorporated into infrastructure and assets and bring considerable savings in averted maintenance costs and energy inefficiencies. The research is detailed in Science Advances.

In a statement, study lead Kyoo-Chul Kenneth Park said: The 2021 power crisis in Texas cost $195bn in damages, resulting directly from frost, ice and extreme cold conditions for more than 160 hours. Thus, it is critical to develop anti-frosting techniques, which are robust for long periods of time in extreme environmental conditions. It is also necessary to develop anti-frosting methods which are easy to fabricate and implement. We designed our hybrid anti-frosting technique with all of these needs in mind. It can prevent frosting for potentially weeks at a time and is scalable, durable and easily fabricated through 3D printing.”

The new study builds on previous work from Park’s laboratory in 2020 when Park and his team discovered that adding millimetre-scale textures to a surface theoretically reduced frost formation by up to 80 per cent. Published in the Proceedings of the National Academy of Sciences, the research was inspired by the geometry of leaves.

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“There is more frost formation on the convex regions of a leaf,” said Park. “On the concave regions [the veins], we see much less frost. People have noticed this for several thousands of years. Remarkably, there was no explanation for how these patterns form. We found that it’s the geometry - not the material - that controls this.”

Through experimental work and computation simulations, Park and his collaborators found that condensation is enhanced on the peaks and suppressed in the valleys of wavy surfaces. The small amount of condensed water in the valleys then evaporates, resulting in a frost-free area.

In the previous study, Park’s team developed a surface featuring millimetre-scale peaks and valleys with small angles in between. In the new study, Park’s team added graphene oxide on flat valleys, which reduced frost formation by 100 per cent. The new surface comprises tiny bumps, with a peak-to-peak distance of 5mm. A 600 microns thick layer of graphene oxide then coats the valleys between peaks.

“Graphene oxide attracts water vapour and then confines water molecules within its structure,” said Park. “So, the graphene oxide layer acts like a container to prevent water vapour from freezing. When we combined graphene oxide with the macrotexture surface, it resisted frost for long times at high supersaturation. The hybrid surface becomes a stable, long-lasting, frost-free zone.”

When comparing Park’s method to other anti-frosting surfaces it was found that superhydrophobic and lubricant-infused surfaces resisted 5-36 per cent of frost formation for up to five hours, while Park’s surface resisted 100 per cent of frost formation for 160 hours.

“Most other anti-frosting surfaces are susceptible to damage from scratches or contamination, which degrades surface performance over time,” said Park. “But our anti-frosting mechanism demonstrates robustness to scratches, cracks and contaminants, extending the life of the surface.”