Tuesday 21 October 2014

How Ultra Dry Waterproof Coating Works

By Estelle Larsen


A lot of industries in construction have demands for better and quality products and equipment to help them in their projects. This is why advancement in technology through research and development are being done in order to provide to these demands. Even so, there are already a few of these technology that are existing and are being used today.

These artificial breakthroughs have been mostly referred from the works of nature and has been adapted into technology. For example, the ultra ever dry waterproof coating can deflect any liquid substance from any surface that it has been applied on. This is greatly useful when it comes with decreasing drag on ships and submarines and also with equipment for construction work.

This is technically called a Superhydrophobic surface where they are intensely hydrophobic which means it deflects water making it impossible for it to be wet. This is taken from nature which is the Lotus Effect. The contact angle for the droplets of water is above one hundred fifty degrees while the roll off or contact angle hysteresis would be less than ten degrees, which is why these water droplets would just slide off from it.

Thomas Young in 1805 was able to define the contact angle through figuring out what forces are acting upon the droplets of fluids on a surface surrounded by air. Basically, the this angle is the intersection between the air, surface, and water would intersect. Visually, the rounder the droplet, the bigger the angle.

This is a nanotechnology where the innovation is at the smallest detail of the surface so the structure would change up to that level. The coating is sprayed on whatever surface as long as it can withhold the material. Most of the time it is used on rain clothes, cement and concrete, glass, and other equipment that are related to construction as well.

It can also deflect hydrocarbons which then makes it oleophobic as well. So water is not the only thing that it deflects but also these types of fluids. But primarily in construction, it is used for tools and other equipments so that the wet cement would not stick on their surfaces.

The coating has its limitations though. When it comes into contact with certain types of chemicals like detergent or mechanical solutions, the effectivity would be stripped off and it would no longer work. This is why it can be very impractical when you are setting this technology in the real world where a lot of environmental factors are in place. This is different with nature where it replenishes and develops the coating by itself.

This issues was resolved after another innovation was made. It uses layers of porous polymer which is made of polyelectrolyte complexes. It is then coated with a fluoroalkylsilane layer which then turns it superhydrophobic. The undercoat, which is the polymer, consists of two other layers. These are poly allylamine hydrochloride and also sulfonated PEEK. They would alternate with polyacrylic acid which the thickness is about three microns.

These compounds provide a layer for durability that even with sever damage, it would still work provided that there is still the coating that is left on the surface. This resulted in a one hundred sixty degrees of contact angle that deflects water droplets effectively. Active repair also happens during a damage since the fluoroalkylsilane would bleed through the damage and coat it.




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