By Christopher Brown of OCDCarCare.com
Ceramic Coating Hydrophobics (Water Behavior) for Automotive Surfaces. . .
Ever Wonder HOW it works to:
- Makes car washing so fast and easy?
- Keeps Vehicles looking cleaner for longer?
. . . The Answer lies in a scientific concept: Surface Free Energy.
Ceramic Coating Hydrophobics a.k.a. Water Behavior a.k.a. Surface Energy: What on Earth is that?
Ceramic coating hydrophobics, defined in auto detailing, refers to how water or contaminants interact with a vehicle’s surface. Typically, focusing on the ability of water and dust particles to rest and stick (adhere) to a surface. Low surface energy is the scientific concept behind the hydrophobic properties, or water behavior, of ceramic coatings.
Within general car care or vehicle cleaning, low surface energy is a positive characteristic, causing water beading and water sheeting. These properties help vehicle surfaces to remain cleaner for longer periods of time and make surfaces easier and faster to clean.
Understanding how positive water behavior is achieved and maintained is important to high quality modern professional auto detailing.
In terms of ceramic nano coatings, low surface energy explains a key benefit which coatings provide to automotive surfaces. Knowledge of surface energy allows for a better understanding, maintenance, and troubleshooting of potential ceramic coating surface issues.
Frequently detailers some ceramic coatings have “failed” when the hydrophobic properties have diminished or stopped. Quite often this is not the case at all. The water behavior characteristics of a surface are dependent on many factors, not just the coating formulation alone.
Read on to explore the fickle nature of hydrophobics. Learn how water behavior is only one aspect of a ceramic coating’s many protective characteristics.
How is Surface Energy Relevant and Important in Auto Detailing?
The free surface energy of automotive surfaces is a topic rarely discussed, yet carries great significance in modern auto detailing.
Since ceramic nano coatings are a standardized surface protection option, understanding surface energy (hydrophobic properties or ‘water behavior’) is more relevant today than ever. Therefore, modern auto detailers should have knowledge of the characteristics of ceramic coatings. This knowledge will prove invaluable for relevant issues that may arise around ceramic coating upkeep and maintenance.
This article was written because little to no information or resources, regarding hydrophobic properties (water behavior), exist to educate vehicle owners, consumers, or auto detailers.
This article’s concepts primarily focus toward the performance and characteristics of ceramic coating hydrophobics. However, MOST of this information is applicable to understanding the surface characteristics for all Last Stage Products (LSP’s); including waxes and sealants.
Ceramic Coating Hydrophobic Properties: Terms & Concepts Defined
Surface energy is a measure of a solid’s surface state.
High Surface Energy means a liquid will have great success adhering to that surface. Think of a pool of water on a sidewalk.
Low Surface Energy means a liquid has difficulty adhering or sticking to a surface, causing it to fall off the surface with relative ease. Think of droplets of water on an umbrella.
Contact Angle measures how a liquid interacts with the surface energy of a solid surface. The higher the contact angle measurement, the more difficulty a liquid has adhering to a solid surface.
Contact angle analyzes how well a single droplet of water touches, or ‘wets’, a surface.
At a very high contact angle, say 145 degrees, water almost appears as three quarters of sphere sitting on top of a surface. With high contact angles, a small portion of the spherical droplet is touching (wetting) the surface.
At a low contact angle, say 30 degrees, a water droplet appears as a small wide pool. A droplet with a contact angle of 30 degrees mostly touches, or wets, the surface.
Most simply: contact angle quantifies the ‘wettability’ of a solid surface by a liquid.
Sliding Angle measures how easily water releases (slides) off of a surface. Specifically it measures the angle at which a drop of water begins to fall down an incline. The lower the sliding angle the easier it is for water, and any topical contamination, to release off of a surface.
Sliding angle is arguably more important than contact angle for measuring the effectiveness of a ceramic nano coating’s hydrophobic characteristics. This is because a low sliding angle typically indicates that water and contamination will easily be removed from vehicle surfaces when cleaned.
A low slide angle aids in many aspects of protection and automotive surface care. Low slide angles help ceramic coatings to avoid hard water spots left by minerals deposits of evaporated water. They also aid in the ‘self cleaning’ ability of coating formulations.
For simplicity’s sake the term “hydrophobic” refers to how the water reacts on the surface– a.k.a. water behavior.
Both terms: Hydrophobic and Hydrophilic use the concept of contact angle to define how a solid surface interacts with liquid.
Hydrophobic literally translates to “fear of water.” A surface is Hydrophobic when liquid contacting it contains a contact angle of 90 degrees or greater. Hydrophobic surfaces are hard to wet.
In contrast, the word Hydrophilic means “friend of water.” Hydrophilic surfaces have water contact angles below 90 degrees.
Think of pouring water onto a typical sidewalk. The water easily rests onto the concrete. There is almost no discernible difference between the water and the concrete. They seem to fuse together to make — wet concrete. That is a hydrophilic surface.
How Topical Contamination Changes a Vehicle’s Hydrophobic Surface Behavior
ALL LSP’s including Waxes, Sealants, and Ceramic (aka Glass) Coatings were partially engineered to protect vehicles by keeping surfaces clean.
The amount of Surface Energy an LSP creates accounts for its ability to repel contaminants and liquid off of vehicle surfaces. Surface Energy scientifically explains how wax ‘beads’ and ceramic coatings ‘sheet’ water.
The common detailing term, often used to describe water beading or sheeting, is ‘hydrophobic;’ literally meaning afraid of water.
When anything layers on top of an LSP the Hydrophobic (water behavior) properties of that LSP can change. This includes almost anything such as dirt, topical contamination, or another product. A Regular vehicle wash schedule helps to keep vehicle surfaces clear of bonded contaminants. This is the only way to ensure surfaces retain their LSP’s hydrophobic properties for extended periods of time.
When vehicle surfaces are NOT cleaned regularly, contamination layers form on the surface. They layer on top of one another like a brick wall over time. Eventually, they build up enough layers to completely cover the coating’s surface. When this occurs the hydrophobic properties of the vehicle surface display the water behavior of the contamination. This results because the contamination layers are now the outer layer of the vehicle’s surface interacting with the environment.
This is why the understanding how surface energy affects hydrophobic characteristics, and how to maintain them through proper washing intervals, is critical to ceramic coating surface performance and longevity.
Speaking of ceramic coatings specifically; often the public, or even some detailers, quickly proclaim a coating has failed when it stops sheeting water. This is not entirely the case when investigating the matter at a surface level.
Most times, a proclaimed coating “failure” is due to topical contamination resting or bonding on top of the coating. This contamination may drastically alter the surface energy characteristics of the surface, masking most or all water behavior.
High Surface Energy. This surface accepts liquid and is therefore ‘wettable’ meaning liquid has the ability to dwell on the surface.
Proper Products to “Layer” or “Top” a Ceramic Nano Coating With…
As a wax, Swissvax Concourso is a stunning choice for automotive finishing. Its high carnauba level causes vehicles to glow with a sexy cinematic halo around them.
However, if a vehicle has a ceramic nano coating applied to its surface, then wax is NOT the correct product to maintain it with. Even if the intent is to add an additional sacrificial barrier of protection.
The ONLY thing to ‘layer’ or ‘top’ a coating with is a long term silica sealant or another semi permanent coating product. It is Highly Recommended, that any topper product should remain in the same chemical family as the ceramic coating. Remaining within a chemical family helps ensure the water behavior maintains continuity of water behavior. Additionally, products from the same chemical family ensures optimal adhesion of the topical product to the ceramic coating.
Putting anything else over a ceramic paint coating, other than these types of topper products, alters the surface energy.
As stated previously, some protection characteristics of a paint coating depend on the ability to remain hydrophobic. This ability is maintained through low surface energy. Using the wrong product on top of a coating can change the water behavior for the worse and negate some of the protection benefits a ceramic coating provides.
The Fickle Nature of a Ceramic Coating’s Hydrophobics (Water Behavior)
The hydrophobics (water behavior) of an automotive ceramic coating are the easiest performance characteristics to measure. However, they are extremely fickle if not maintained properly or are neglected for long periods of time.
It is quite simple to negatively alter the water behavior of a coating. This is the exact reason why most coatings companies insist on or stress regular wash intervals for coated vehicle surfaces.
With a regular vehicle washing routine, surfaces stay clean and smooth by avoiding topical bonded contamination build up. A regularly cleaned surface allows a coating’s water behavior to function at peak levels. This occurs because the coating’s surface energy is directly interacting with the environment. This allows vehicle owners and auto detailers to easily identify the coating’s significant hydrophobic properties.
Ease of maintenance and the ability to keep vehicle surfaces clean are prime benefits and selling points of ceramic nano coating technology. These traits only occur when the coating maintains its original properties of low surface energy.
In short, wash your vehicle regularly to maintain an automotive ceramic coating’s optimal water behavior.
For a more in-depth look into vehicle washing read our article “Detailing DIY How To: How Often Should I Wash my Car?“
Auto Detailing and Misinterpretations of Ceramic Coating Water Behavior
A change in water behavior ( the state of surface free energy) alone is never a reliable indication of a coating failure.
Hydrophobic ‘failure’ could easily happen by smearing olive oil or a finish polish over a coated section. Whatever residue remained after wiping either smeared liquid off the surface would negatively alter the water behavior of that coated section. The coating’s hydrophobics would appear very weak or maybe to be gone entirely.
This example only indicates that surface energy has shifted away from the ideal characteristics of the coating to the properties of the left over polish or olive oil. This does not automatically mean coating failure, but rather the hydrophobic properties are masked by whatever rests on top of it.
Often, vehicle owners or detailers form snap judgements or conclusions about ceramic coating effectiveness or durability based on hydrophobic properties.
Frequently these opinions are without a true or full understanding of the principals behind vehicle surface energy. This type of uninformed dialogue floods literally hundreds of online forums and social media groups, many times marketing related.
Let’s set the record straight:
Hydrophobics, or Water Behavior, alone do not provide an accurate picture of automotive ceramic nano coatings and their overall protection characteristics.
Hydrophobics are only one, highly specific aspect of the overall protection offered by ceramic coatings.
When a coating ‘fails,’ to produce water beading or sheeting, most times topical surface contamination is the culprit. Surface contamination generally builds up from neglecting to execute regular cleanings or from a heavy and durable contaminant.
Final Words on Ceramic Coating Hydrophobics in Auto Detailing
Vehicle surfaces require regular maintenance (washing) to keep them free of topical contamination. Clean surfaces optimize the effects of water behavior of all surface protection, including ceramic nano coatings, sealants, and waxes.
If surface contamination builds up enough it becomes the vehicle’s surface. Eventually, contaminated vehicle panels adopt the surface energy (hydrophobic) properties of this outermost contamination layer.
This does not a clear indication that a ceramic coating has automatically failed. Most likely, the surface is highly contaminated, therefore masking the ceramic coating hydrophobics.
If a coating exhibits poor water behavior, its other protective qualities are not automatically gone. A ceramic nano coating’s benefits and protective capabilities of: UV protection, chemical resistance, enhanced ‘hardness’, gloss, and measurable thickness; do not vanish if the surface does not sheet liquid.
The myth exists within the detailing world that a coating’s overall quality and durability relate directly to water behavior. Unfortunately, some individuals boldly proclaim complete coating failures within 6 months, due to a lack of hydrophobic water behavior on vehicle surfaces. This is definitely not always the case.
**Warning: Next time you think a ceramic nano coating or wax is ‘bad’ or has ‘failed’, first consider the vehicle panel’s surface energy. Surface energy plays a critical role in surface care within automotive detailing. Understanding of the science, and properties associated, of surface energy will arm detailers with knowledge that will improve surface issue troubleshooting.
“ALWAYS Keep Learning to Strengthen Your Passion & Your Business.”
© Christopher Brown – OCDCarCare Los Angeles
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