Researchers in China and Finland have developed armour-plated superhydrophobic surfaces that repel liquids with what is claimed to be ‘world-record effectiveness’.

Superhydrophobic surfaces are extremely useful for antimicrobial coatings because bacteria, viruses and other pathogens cannot hold on to their surfaces. Such surfaces are, however, susceptible to cuts, scratches or dents that can trap liquids and render the coatings ineffective.
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The research – featured in Nature – is said to have designed superhydrophobic surfaces that can be made from metal, glass, or ceramic. The superhydrophobic properties of the surface come from nano-sized structures spread over it. The surface of the material is patterned with a honeycomb-like structure of tiny inverted pyramids. The water-repellent chemical is then coated on the inside the honeycomb. This prevents any liquid from sticking to the surface, and the delicate chemical coating is protected from damage by the pyramid’s walls.
“The armour can be made from almost any material, it’s the interconnection of the surface frame that makes it strong and rigid,” said Professor Robin Ras, a physicist at Aalto University whose research group was part of the project. “We made the armour with honeycombs of different sizes, shapes and materials. The beauty of this result is that it is a generic concept that fits for many different materials, giving us the flexibility to design a wide range of durable waterproof surfaces.”
The superhydrophobic surfaces can also be used more generally in any application requiring a liquid-repellent surface, such as photovoltaics where the build-up of moisture and dirt over time blocks the amount of light they can absorb.
Making a solar panel out of a superhydrophobic glass surface would maintain their efficiencies over long periods of time. Furthermore, as solar cells are often on roof tops and other difficult to reach locations, the repellent coatings would cut down the amount of cleaning required.
“By using the decoupled design, we introduce a new approach for designing a robust superhydrophobic surface. Our future work would be to push this method further, and to transfer robust superhydrophobic surfaces to different materials and its commercialisation” said Professor Xu Deng, the leader of the group at the University of Electronic Science and Technology of China in Chengdu who took part in this research.
Other desirable applications for superhydrophobic surfaces include in machines and on vehicles, where conditions can be challenging for brittle materials over long periods of time. To simulate these working environments, the researchers are said to have subjected their new surfaces to extreme conditions, including baking them at 100°C non-stop for weeks, immersing them in highly corrosive liquids for hours, blasting them with high-pressure water jets, and subjecting them to physical exertion in extreme humidity. According the team, the surfaces were still able to repel liquid as effectively as before.
Now that the strengths of this new material design have been demonstrated, future research will explore its real-world applications.
Could have applications in food processing, pharmaceuticals, kitchenware, glassware and cleaning technology.
No information about the transparency that they can achieve, so one can’t see whether the application to solar panels and mirrors would be effective (or not).
I guess it is very early days and this isn’t out of the lab yet. But worth watching!
Dear Rob,
The surfaces we describe in our paper in Nature are transparent. See in Figure 2g and Figure 4e-f where we demonstrate a solar cell application. You can get free access to the paper here. https://rdcu.be/b4BiD
Best wishes,
Robin Ras
Aalto University, Espoo, Finland
robin.ras@aalto.fi
i have thought that this type of surface would make much more effective solar cells ever since reading about it because not only does the solar cell improve because of its self=cleaning nature. But it also should increase in efficiency simply because the available surface area of the solar panel will increase. It is a concept i came up with many years ago to add depth to solar panels which would increase the surface area of the panel within the same space. It would of course mean using more silicon within that space. But surely if you can double the amount of surface area and silicon used within each sqmm then you double the amount of power produced from that sqmm.
Are there any solar panels with this surface?
Can this surface be applied in the field to solar panel glass and last over 10 years?