How Ceramic Coatings Work: Detailing Hydrophobic Science Explained
By Christopher Brown of OCDCarCare Los Angeles – OCDCarCare.com – 17 Jan 2017
- how ceramic nano coatings make vehicles so easy to clean?
- Or why vehicles treated with ceramic coatings seem to stay cleaner longer?
. . . The Answer lies in a little known scientific concept called: Surface Free Energy.
Surface Energy, a.k.a. What on Earth is that?
Surface Energy, in auto detailing terms, is the discussion of how water or contaminants interact with a vehicle’s surface. Typically, this subject appears in conversations surrounding the ability of water and dust particles to cling to a surface.
Within general car care or vehicle cleaning, this is a good thing because low Surface Energy causes water beading, water sheeting, and helps vehicle surfaces to remain cleaner.
In terms of ceramic paint coatings, Surface Energy is crucial because it explains many key vehicle owner benefits which paint coatings provide to automobiles. Additionally, understanding surface energy provides detailers with knowledge which can help them better understand, maintain, and troubleshoot potential ceramic coating surface issues.
Hydrophobicity or Surface Energy Scientifically Explained
Surface energy is a measure of a solid surface state. High surface energy means a liquid will have great success adhering to that surface. Conversely, a lower surface energy, the more difficulty a liquid has adhering or sticking to a surface. Usually causing it to fall off the surface with relative ease.
Contact Angle measures how a liquid interacts with the surface free energy of a solid surface. The higher the contact angle measurement, the more difficulty a liquid has adhering to a solid surface. Contact angle is measured between a liquid droplet’s edge and the solid surface it rests upon. At a very high contact angle, say 145 degrees, water appears as almost three quarters of sphere sitting on top of a surface. Therefore, only a small portion of the liquid droplet touches the solid surface. At a low contact angle, say 30 degrees, water appears as a small wide pool, touching (wetting) the surface.
The terms Hydrophobic and Hydrophilic use contact angle to define how a solid surface interacts with liquid. The word Hydrophobic 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.
On the other hand Hydrophilic “friend of water” surfaces have 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.
Most simply: contact angle quantifies the ‘wettability’ of a solid surface by a liquid.
How is Surface Energy Relevant and Important in Auto Detailing?
Surface Free Energy of automotive surfaces is a topic rarely discussed, yet carries much significance in today’s detailing climate. Without an understanding of this concept, it may be difficult for detailers to evaluate and plan solutions for common auto detailing issues arising from the behavior characteristics of vehicle surfaces.
Surface Energy is even more relevant today than ever, since ceramic paint coatings are a staple surface protection option. Therefore, detailers need a solid understanding of the technology and properties behind ceramic nano coating technology. This may prove invaluable for relevant issues that may arise around ceramic nano coating upkeep and maintenance.
This article was written because little to no information or resource regarding this subject exists to educate consumers or detailers. This article’s concepts primarily focus toward the performance and characteristics of ceramic nano coatings. However, MOST of this information is applicable to the understanding the surface characteristics for all Last Stage Products (LSP’s); including waxes and sealants.
How Topical Vehicle Contamination Changes Hydrophobic Surface Behavior
ALL LSP’s including Waxes, Sealants, and Ceramic Nano (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 blanket detailing industry term, often used to describe water beading or sheeting, is ‘hydrophobic;’ literally meaning afraid of water.
When anything layers on top of an LSP; such as dirt, topical contamination, or another product, the Hydrophobic properties of that LSP can change. Regular vehicle wash schedules assist in keeping vehicle surfaces clear of contaminants. This is the only way to ensure surfaces retain their LSP’s hydrophobic properties for extended periods of time.
In regards to 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 coating “failure” is due to topical contamination or something else layered on top of the coating. This may drastically alter the surface energy characteristics of the surface, masking most or all water behavior.
To Layer, or not to Layer or “Top”, Ceramic Nano Coatings?
As a wax, Swissvax Concourso is a stunning choice for automotive finishing. Its high carnauba content causes vehicles to glow with a sexy cinematic halo around them, creating a gorgeous presence. However, if a vehicle has a ceramic nano coating applied to its surface, then wax is NOT the correct to maintain it with. Even if adding as 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. Preferably, a topper product should remain in the same chemical family as the ceramic nano coating. Remaining within a chemical family helps ensure the water behavior maintains continuity of surface energy from the base coating and ensures optimal adhesion of the topical product.
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.
The Fickle Nature of Ceramic Coating Surface Energy
The surface energy, and most of the measurable performance characteristics, of ceramic paint coatings are quite fickle if not maintained. It is actually quite simple to drastically alter the surface energy of a coating.. This is the exact reason why most coatings companies insist/stress regular wash intervals for coated vehicle surfaces.
With regular maintenance, ceramic coating water behavior remains optimal, allowing vehicle owners to visibly identify the coating’s hydrophobic abilities. Ease of maintenance and the ability to keep vehicle surfaces clean are prime benefits and selling points of ceramic nano coating technology. This occurs because the coating maintains its original intended outermost surface energy properties. Therefore, adding anything which drastically alters the ceramic nano coating’s original surface properties is highly inadvisable.
The Detailing Industry and Misinterpretations of Ceramic Coating Water Behavior
A change in surface free energy alone is never a reliable indication of coating failure. Hydrophobic ‘failure’ could easily happen by smearing olive oil or a finish polish over a coated section. Whatever residue remained after wiping the surface would alter the water behavior of that coated section. Therefore, 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. This does not automatically mean coating failure, but rather its hydrophobic properties are masked by whatever was put on top of it. In this case, a finish polish.
Often, customers 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. Surface characteristics alone do not provide an accurate picture of a ceramic nano coating and its overall protection characteristics.
When a coating ‘fails,’ to produce water beading or sheeting, most times topical surface contamination is the culprit. This contamination build up most frequently from infrequent wash intervals that allow contamination to layer and cover the coating’s surface. Detailers and consumers can avoid falling into the pitfalls of misjudging products with better knowledge. Therefore, the understanding how surface energy affects hydrophobic characteristics for surface performance and longevity is crucial.
Final Words on Surface Energy, Ceramic Paint Coatings, and Waxes 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 ceramic nano coatings and waxes. If surface contamination builds up, that contamination eventually becomes the vehicle’s surface. When this occurs the paint adopts the surface energy properties of this outermost contamination layer. This does not automatically mean ceramic coating or wax failure. Most likely the surface is highly contaminated, therefore masking the properties of the LSP.
If a coating exhibits poor water behavior, its other protective qualities are not automatically gone. The Ceramic Nano Coating 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. Unfortunately, the myth exists within the detailing world that a coating’s overall quality and durability do relate to water behavior. Some even boldly proclaim complete coating failures within 6 months, due to a lack of hydrophobic water behavior. This is definitely not always the case.
Next time you believe a ceramic nano coating or wax is ‘bad’ or has ‘failed’, first consider the vehicle’s surface energy. Surface energy plays a critical role in surface care within automotive detailing. The understanding of the science and properties associated with surface energy with arm detailers with knowledge that will improve troubleshooting on possible surface issues.
~Keep on Buffin’
© Christopher Brown of OCDCarCare Los Angeles – OCDCarCare.com – 2017
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