Defrosting the ice off equipment is common practice in colder countries.
For instance, planes frequently have to be de-iced before taking off. However, the de-icing agents are not eco-friendly and require frequent use.
Now, scientists at Incheon National University, South Korea, have developed a self-forming icephobic coating using a superhydrophobic surface that offers consistent protection from ice.
Cost-effective and simple to develop, the new coating could protect devices operating under rough weather.
Devices and infrastructures regularly operating under sub-zero conditions and rough weathers need to be robust against ice formation, which can, otherwise, cause critical damages and/or safety issues.
While several methods are in place to check ice formation, such as heating, scrapping, applying salt or anti-freeze, all of them are rather expensive, inefficient, and environmentally hazardous.
One potential alternative to conventional ice removal methods are icephobic coatings.
These are similar to hydrophobic surfaces with low-surface energies to discourage ice formation.
The coatings typically have a high roughness, discouraging contact with any ice that forms on them.
Maintaining such a low contact area reduces the adhesion force between the ice and the surface, allowing any ice that forms to slide off easily.
However, the fabrication methods for increasing the surface roughness are expensive and complex, limiting the application of these coatings.
Now, a research team led by Associate Professor Han-Bo-Ram Lee from Incheon National University, South Korea have developed a low-cost icephobic coating that can be easily applied on surfaces.
The researchers had previously developed a superhydrophobic coating using polydimethylsiloxane (PDMS) – a non-toxic polymer well known for its hydrophobic properties.
Now, in a new study, they tested its effectiveness under icing conditions and found it to be a suitable icephobic coating.
The study was published in ACS Applied Materials & Interfaces.
The hydrophobic coating was prepared on a stainless-steel substrate using PDMS and silicon dioxide (SiO2) powders.
The procedure involved sprinkling SiO2 powder on a stainless-steel substrate coated with PDMS.
As it turns out, the SiO2 particles get spontaneously coated by the PDMS coating.
“We call the mechanism ‘Biscuit-Dunking Effect’ and have seen that many times on our cup of coffee,” explains Prof. Lee.
“So, the coating layer is formed through a spontaneous process similar to the biscuit sucking in the coffee”.
SiO2 powder added to the coating increased its surface roughness and improved the icephobic and hydrophobic properties of the coating.
However, it still had poor mechanical properties and low adhesion strength, properties crucial for withstanding harsh environmental conditions experienced during ice formation and ensuring constant protection.
To compensate for this, the team added polyvinylidene fluoride (PVDF) to the PDMS solution, improving the durability and the adhesion properties of the coating.
The result was an icephobic coating consisting of SiO2 particles on a hydrophobic layer of PDMS and PVDF.
Compared to the conventional fabricating techniques, the proposed method uses simple processes and is cost-effective, enabling it to be used in a variety of situations and surfaces.
“The icephobic coating using PDMS−PVDF and SiO2 powder can be applied to large-area surfaces with reliable mechanical properties, and it has considerable potential for applications in coating appliances, such as antennas and objects exposed to harsh environments, including Polar Regions and the outer space,” says Prof. Lee.