Hydrophobic coatings: spray or plasma?

Over the past few weeks there has been a lot of excitement regarding hydrophobic coatings in a can. In fact, many people ask us whether they can buy a spray-can of our coating to treat their household items. I asked the scientists at P2i for some extra info on the difference between spray-can coating and the plasma tech they use:

How do hydrophobic coatings work?

Hydrophobic coatings create a layer on top of a surface to repel water and other liquids. Because of the low surface energy created by the coating, water beads into droplets and can therefor easily roll away from the surface. 

Why doesn't P2i offer a spray coating?

There are two big differences between P2i’s plasma coating and spray-can coatings: the size of the layering and the durability. When you spray a substance out of a can onto a surface you are going to create a layer which is microns thick. Now on an online video this looks very impressive, but if you could feel the product yourself, you would immediately notice a difference. A coating which is microns thick is at a size that the human body can detect through touch (with a waxy texture or feel), and at a size that is visible, causing discoloration or a white substance you can physically see.

When you look at the types of products P2i applies its technology to, it becomes clear why spray application is not an option. For example on delicate electronics, P2i’s nano-coating is so thin that it doesn't change the thermal properties of the device. This means that it is not in danger of overheating smartphones or tablets. And at a thousand times thinner than a human hair you wouldn't even know it’s there!

How is it applied?

P2i’s coating is applied in a process called “plasma enhanced vapor deposition”. The process involves three steps.

Step One: the item is placed into a chamber which is brought down to very low pressure.

Step Two: Plasma activates the surfaces of the device making them ready to bond to the monomer which is applied as a vapor. 

Step Three: Further plasma polymerizes the monomer forming a nano-coating layer over and within the product. The chamber is brought back up to room pressure and the item removed.

So there are a few key pieces to this puzzle which ensures a more durable performance than a spray coating. Firstly, because the product is applied in a vacuum it means the vapor can get through to every nook and cranny. In fact the coating can reach nearly anywhere air can go. This means there are no weak points to attract moisture or allow corrosion damage. Secondly, the plasma activation of the surfaces ensures that the coating is chemically bonded to the product, becoming part of its physical make-up, not simply sitting on the surface where it can wipe or rub off. Finally, the plasma polymerization means the coating is applied evenly across the surfaces and so doesn't end up with clumping or disproportionately thicker and thinner points.

Where is it used?  

     

P2i works with the likes of Motorola to apply the splash-proof coating on to tablets and smartphones to give greater liquid protection, while Plantronics use it on their headsets to protect against sweat and moisture damage. Because P2i works directly with brands and manufacturers to apply the technology during production, it is essential that the coating performs to high standards and is durable for everyday use.