Hydrophobic Vs Antistatic Coating
"Phobic" comes from the Greek root "phobos," meaning "fear," and "hydro" refers to water, which in the literal sense the word means "fear of water."
Hydrophobicity is a property that lacks affinity for water, does not absorb or mix with it, referring to a surface that repels water and water-based materials.
The molecules of hydrophobic agents are typically non-polar (no positive or negative charge zones), when water and water-based materials come into contact with a hydrophobic surface, these drops spread and slide easily off the surface.
Glass has a typically hydrophilic behaviour by nature, i.e. water molecules falling on glass tend to stick to its surface. Hydrophobic coatings for glass change the behaviour of the surface, making them hydrophobic and repelling water drops. Theoretically, the maximum hydrophobicity is 180°, and in this case a droplet is perfectly spherical, contacting the surface at a singular, almost imperceptible point. Water and water-based materials appear to bounce off a hydrophobic surface, where it looks as if it is exerting a force against the drop of water and pushing it away, however this is not what happens, there is simply no attraction between the surface and the drop of water, as if the drop cannot hold on and just slides away.
How does it work?
This type of coating when applied to the glass of the solar panels changes the behaviour of its surface, which begins to repel water droplets. The hydrophobic coating provides an invisible, durable film that offers waterproofing, residue-resistant properties.
In times of rain, the water drops that fall on the hydrophobic surface, agglomerate and eventually slide off the panel (when it is installed with a certain inclination) dragging the dirt particles with them, thus conferring self-cleaning properties. D-Solar Defender and IGP developed by ChemiTek are examples of hydrophobic coatings, which help to clean surfaces.
An Antistatic coating has properties that prevent or limit the formation of static electricity. An antistatic agent is an agent used for the treatment of materials or surfaces in order to reduce or eliminate the accumulation of static electricity.
The electrostatic energy present on the surface of objects is caused by the imbalance between the positive and negative charges of the material. This energy is responsible for the forces of attraction between the material surface and certain dirt particles, causing the deposition of these particles and making it difficult to clean the materials. The role of an antistatic agent is to make the surface or the material itself slightly conductive.
When we talk about the behaviour of this type of coating on the glass of solar panels, its properties have the objective of repelling the dirt deposited on the glass, avoiding the adherence of dirt to the glass, which causes these particles to easily detach from the glass of the solar panel.
How does it work?
Antistatic agents are compounds which dissipate this electrostatic energy, reducing the attraction between the surface of the material and the dirt particles. Therefore, antistatic coatings reduce the attraction between dirt and the surface of the solar panel, reducing the accumulation of dirt and facilitating the cleaning process.
Which is the best option to keep my solar panels clean for longer?
Both coatings make cleaning the solar panels easier and help them stay clean for longer. However, the choice of which one to apply should be based on the type of climate in which the solar panels are installed:
· Mild climates, with moderate periods of rain, anti-static coating is recommended;
· Extreme climates (environments with a lot of rain) hydrophobic coating is recommended.