Nanoscale technologies are the development and use of devices that have a size of only a few nanometers. The prefix nano means ten to the minus ninth power (10 ‾‾ ⁹), or one billionth of a meter, a simple metric measurement.

However, what’s relevant is not the thickness of the coating itself (1-100 nanometers or some other “micro” measurement) but rather:

• What the coating actually is.
• What does it do?
• By what process does it work?
• What does it provide as an overall ADDED-VALUE product?

Therefore, just because something can be measured on the nanoscale level, it is not a guarantee of quality. Many chemicals can be spread out thin enough to be measured on the nanoscale, but it does infer a degree of inventiveness and does enable certain capabilities by virtue of being able to manipulate atoms at that much smaller levels.

An integrated permanent bond

In the case of the self clean coating Balcony systems uses, the chemical treatment itself provides, in chemical terms, a very durable “branched, cross-linked and capped” optically clear nano-film and a permanent bond is integrated into the glass itself as the nanofilm actually grows from the inside out and literally changes the molecular composition of the surface. This is truly a unique process unlike any other coating.

How will the coating stand over time

The KEY is durability and how the coating, nano or not, will stand over time, and how that “bubble” (water droplet), as defined by the contact angle measurement, will behave with the passage of time, namely normal wear and tear.

The nanotechnology behind the product

More specifically, this nanotechnology, patented worldwide, uses a two-stage chemical process. The chemical reaction created in the first stage causes the “cross-linked” and “branched” ultra thin silicone film (nanofilm) to be grown from below the surface out.

The second stage ‘caps’ the entire chain of atoms. This unique ‘capping’ substantially increases the hydrophobicity and durability, leaving, chemically speaking, no points of attachment for contaminants and creating a truly repellant charge. Through simple neutralization, all chemicals become inert within a few seconds. No curing time is needed since the chemical reaction itself occurs in less than 2 seconds.

The pyrolytic Self-cleaning glass consists of a hydrophilic coating with photocatalytic properties fused into the glass at high temperatures during the manufacturing process.

This type of coating typically reacts with the sun’s ultraviolet light and water (rain or induced water spray). Thus, these two elements (sunlight and water) must be present for the coating to be effective, creating a sheeting action so that water can easily rinse the loosened dirt away.

Due to its integral characteristics, there are many limitations to this concept of “self-cleaning”, such as the following:

• glass must receive both sunlight and water
• it is not applicable to all kinds of glass
• cannot be applied in the field but rather at manufacturing level only (making repair or replacement a lot more expensive)
• it’s typically a lot more expensive than hydrophobic coatings.

By contrast, hydrophobic coating requires no ‘activation’ since it chemically reacts during its own process in less than 2 seconds and immediately bonds to the surface. Although othertheories refer to the “self-cleaning” glass as those coatings with contact angles in excess of 105º, where the mechanical action required is virtual unnecessary and no accumulation of contaminants occurs.

This is probably the single most relevant question one can ask about any hydrophobic easy-to-clean coating and perhaps the MOST HIDDEN fact by most coating suppliers as it truly uncovers the truth behind the quality of the product. Yet, most coating suppliers will typically evade this critical issue with all sorts of misleading statements and false claims:

The unequivocal and irrefutable scientific FACT

The important fact to know is not necessarily the initial contact angle measurement after the glass surface is treated but rather how it will perform over time or, in other words, how will the contact angle behave with the normal tear and wear once the surface is exposed to the different environments.

Most hydrophobic easy-to-clean coatings have an initial contact angle anywhere from as low as 80 degrees to 120 degrees. The ones that are on the low end, especially under 95 degrees, are not interested, for obvious reasons, in disclosing any measurement thus they downplay or completely disregard any value to contact angle measurements, as they would not want to lose any “marketing edge” vs. any higher contact angle coating.

The contact angle measurement varies over time

You may hear a supplier calling this issue “the war of the bubbles” and the lack of relevancy they allocate since it really “doesn’t matter”, they claim. NOT quite so as it does matter and you should know why to therefore make a smart decision when choosing a coating for your own use, whether you are the owner of a building, business or simply for your own household or automotive use.

Specifically, the important aspect is to know how the contact angle measurement varies over time, thus if your coated surface still remains at a relatively high contact angle AFTER a significant period of time, let’s say after 1,2, 3 and more years to then be able to TRULY ASSESS the quality of the coating without the need to re-apply every few months, which is the case with MOST other coatings as they do not have a PERMANENT BOND.

Mediocre, good and excellent hydrophobic coatings

This is simply a matter of accuracy and disclosure of scientific facts that DO affect your every day life by having access to improved performance. The same way anyone likes having the best cleaner in the house, or perhaps the best paint for the living room walls, one should know the difference between mediocre, good and excellent hydrophobic coatings to enhance your glass surfaces and keep it cleaner for longer periods of time thus reducing the required maintenance.

The measurement that defines how water-repellent a surface is after being treated with a hydrophobic coating is called “contact angle”, also called ‘wetting angle’, which is the angle formed by the material’s surface and the tangent of the interface between the fluid (i.e.: water) and the environment at the point of contact (the glass surface for example).

Visit this Wikipedia webpage or further “contact angle” information