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What Is A Hydrophobic Coating? The Definitive Answer


The term hydrophobic coating is a bit of an unknown. Most homeowners are unfamiliar with this term, but considering the benefits such coatings provide, it’s well worth learning the science behind the theory, and how it helps your home.

In light of this fact, we’ve compiled the essential guide to hydrophobic coatings, and how they perform in practice. Here’s the lowdown…

What Is A Hydrophobic Coating?

Let’s start with the question what is a hydrophobic coating. The simple explanation lies in the word “hydrophobic”. The definition of the word is “tending to repel or fail to mix with water”. In other words, a coating that has hydrophobic properties will block water.

Advantages of hydrophobic coatings include: dirt retention, improved moisture resistance, improved corrosion resistance, self-cleanability, and extended life expectancy of the coating.

One of the reasons people are confused is because of the appearance of words like hydrophilic and super hydrophobic coatings. Let’s explore the differences between them in greater detail:

Difference Between Hydrophobic and Super hydrophobic

To start with, we have to define the relationship between the contact angle, and the character of the surface. This is the main difference between the coatings, and everything else is defined by that angle.

Hydrophobic coatings have a contact angle of ≥ 120°. Super hydrophobic surfaces have an angle of ≥ 150°. They are highly water-repellent, and, consequently, the best option for areas that experience high levels of moisture.

What are the factors that impact the angle of a water drop on the surface? The most important factors are the micro, macro, and nano-surface profile, as well as the surface tension of the coating.

Put simply, surface tension is the “elastic tendency of liquids that make them acquire the least surface area possible”. Water has a higher surface tension than common solvents.

As mentioned before, super hydrophobic is often thrown out there as a term, to the point where it became the “common nomenclature” for surfaces that repel liquids. And sometimes, it is used correctly.

However, don’t be fooled: Super hydrophobic coatings are not durable. We are not yet to the point where the technology is quite there yet.

A hydrophobic coating, on the other hand, is highly durable, and it is presently the best protection against liquids, moisture, and everything that comes with it.

Difference between hydrophobic and hydrophilic

Get your protractor at the ready: the difference is in the angle again. A hydrophilic coating is polarised, and has an angle of just 30 degrees. That makes the coating attracted to water.

A hydrophilic coating is polar, while a hydrophobic coating is non-polar. That is why the latter repels water and other liquids.

When water touches a hydrophobic surface, the droplets begin to accumulate, causing it to have a large contact angle.

On the other hand, with hydrophilic coatings, the surface attracts water and allows liquids to wet the surface. We all know that wet surfaces have lower insulation properties. But we will get to that later on in this article.

What is a hydrophobic coating

Where Can These Coatings Be Used?

By now, we know the answer to the question ‘what is a hydrophobic coating.’ But where exactly is it used? Hydrophobic coatings can be used for different surfaces, and different materials. This includes: glass, ceramics, metals, and many more.

Many industries have utilised hydrophobic coatings to improve the thermal performance of their buildings. In the building and construction industry, these coatings are increase insulation properties immeasurably.

For example, for optical applications, a hydrophobic coating is used for sunglasses and consumer optics, high tech optical components, lasers and precision optics, goggles, sapphire optics and much more.

For display applications, this particular coating is used for video optical components, cellphones, smartphones, pen applications, LCD, plasma, projection displays, and OEM treatments.

The coating also finds usage for electronics application, mainly for inkjet repellency, antiwetting applications, microfluidic channels, stainless steel components, needles, hard disc drives, and much more.

For industrial applications, you can use these coatings for stainless steel, pipe treatments, metal treatments, syringes, aluminium cans and much more.

How hydrophobic surfaces help my home?

We are finally at the part where we explore how this type of coating helps your home. Well, let’s ask the question, do you want to see walls with mould in your home? Do you understand how condensation works?

We offer a wall insulation product that will vastly reduce the chances of mould appearing on your internal walls. This multi-purpose insulation material can insulate any porous building material, by chemically bonding to the surface.

The product penetrates up to 17mm deep, creating an invisible barrier of protection against inclement weather.

This barrier will reduce the water absorption of your walls by more than 95%, meaning that most, if not all water will repel from the surface.

By doing that, the wall insulation will help you keep your home hot in the Winter, and cool in the Summer. Damp reduces the thermal conductivity of your home. Consider this for a moment. If the pores of the wall collect moisture, heat is transferred through the wall. This happens when there is dampness.

Tests have shown that damp content of just 5% in a plain brick wall will lower your insulation properties by more than 50%. That means that you are basically paying for no-insulation, despite having ample insulation in your walls.

Porous building materials including brick, solid brick, and natural stone have air-filled cavities that have low thermal conductivity only when they are dry. When they are wet, the properties are lower.

Our wall insulation product is based on the latest nanotechnology that reacts with mineral groups and bonds to the surface. It can protect not only against moisture, but also against dirt, algae, pollution, and other issues.

In the rainy British climate, this wall insulation will save you money, and increase your overall level of comfort.

The lifespan of the product is more than 20 years. Once applied, the insulation makes your home breathable, and permeable to water vapour. Breathing masonries improve insulation properties. And the best part is, the product is self-cleaning.

We mentioned when answering what is a hydrophobic coating that it is a coating that is self-cleanable. The product does not allow dirt particles to obtain a hold on the brickwork. They just flow off with rainfall.

Our team of professional contractors will inspect your property, your outside walls, and identify the problems. We perform a thorough, cleaning procedure, before applying the coating to your exterior walls.

With techniques like power washing and algae treatment, we make sure your walls are primed to perfection, and ready for application. We will also re-render if there are any signs of damaged render on your walls.

Finally, after applying a long lasting protective hydrophobic coating to the exterior surface, we will clean the site, leaving you with comfortable home to relax in, whatever the weather outside.

Desperate to keep your home’s exterior looking attractive for longer? External wall coatings help you achieve this-and many more things besides. Simply by calling 0800 1700 636, or  click the button below to request your free site survey today!

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