Tuesday, 27 October 2015

The Science behind Coatings

About the author:
As a scientist / detailer I always question new product developments and the latest advances in coating technology in the world of car care.  By having some understanding of the ‘What’ and ‘Why’ as well as the ‘How’ along with a little science to help you understand how the chemicals we use react, you can achieve the results you desire. - http://togwt1980.blogspot.co.uk/2015/05/about-author.html

Coatings:

Definition [: any paint protection product that contains synthetic ingredients intended to bond to the paint surface as a barrier to provide protection as well as a clear, high gloss finish. They are considered semi-permanent as they cross-link to the paint and can only be removed by abrasive machine polishing]

2004 and what is probably the greatest impact has come from the use of micro technology coatings, which have completely changed the landscape of the detailing industry. Products like Zaino, Collinite, etc. used to be the best protection available but micro technology products offer greatly extended durability, scratch resistance, and protection from the elements that are measured in seasons or years, as opposed to weeks or months.

Paint sealants compared to Coatings
Paint sealants are synthetic products designed for long-term paint protection and easy application. They are composed mainly of amino functional polymers, which last longer than any natural wax and are highly resistant to the elements. Synthetic liquid waxes are another way of describing paint sealants. The main benefit of a paint sealant is their durability compared to a wax, polymer-based sealants will last anywhere from 3 to 6 months.

A coating is applied to a clean surface and is capable of a micro structure 'film build', that is to say, a measurable thickness, that surface takes on properties that are virtually identical to hardened glass. It is chemically inert and will not react with the base material. In other words, dirt will not bond to the treated surface, thereby reducing soiling and organic staining. Acid rain and other chemical compounds easily wash off, significantly reducing the hygroscopic nature of surfaces exposed to industrial or environmental pollution.


Coating particulate organization 

The advantages of coating
Paint surface coatings provide a far superior all-around protection compared to traditional waxes or sealants. The layer of protection that a coating provides is measurably thicker and has a much better chemical resistant. This would prove beneficial in the event that a vehicle is subjected to acidic attack from bird excrement, insect inners and carcasses, acid rain and etc. The thicker chemical resistant coating will make it more difficult for these types of contaminates to penetrate the protection and damage the paint matrix.

Warranty Promises:
Most if not all the automotive coating companies have an insurance company underwrite their warranty. Most of these have loopholes within their warranties to allow easy denial of potential claims.

Coating Marketing Claims:
Another big issue with many coatings is the misleading information claims. For example, the advertising will make frequent mention of Hardness.
Scratch resistance is directly related to higher cross-link density and elasticity of the coating network as well as the surface’s friction resistance. Modern clear coat urethane even though they are harder than lacquer paints, they still scratch more easily. And because they tend to be harder it's more difficult and time consumer to remove swirls and scratches.

This is the main reason to take vendor claims of ‘provides 9H hardness ‘for what it is – totally irrelevant.  
How can a dense (hard) clear coat be so easily scratched? Force acts through a body that has a surface area; if the surface area is really small while maintaining an equal force, the pressure becomes astronomical and the object under pressure capable of penetrating the surface of an otherwise tough material. (Newton's third law of motion)

Swirl marks, marring, scratches, scuffs, scrapes, chips to the painted surface: most of these defects are excluded from the warranty, the only way these surface defects can be avoided is by using correct surface washing and drying techniques; regardless of what coating is use’
The problem isn’t with the coatings, problem lies in the methods in which many of them are marketed and sold. Coatings are not a ‘miracle product’; I’ve been using hem form more than three decades and not just on automobiles, but on various US defence projects (submarine tanks and jet aircraft0 as well as the Aerospace industry.

They offer superior protection against acidic attack and ultra violet radiation damage from the elements, they are easier to clean and resist dirt thanks to the Lotus effect, which helps to keep the surface cleaner and for much longer


They will not render a surface maintenance-free, but by proper and regular cleaning and care they will maintain your automobiles condition and ultimately its resale value

What are Some Downsides?
When considering one of these coatings, the pros and cons for a consumer may be different than those of a specialized detailer.

Before you can even apply the coating, the surface has to be 100% free of surface blemishes, which applies to even brand new vehicles. A multi-stage paint correction involves washing the car, decontamination, removing surface scratches and blemishes by machine buffing, and keeping it pristine while applying the coating. Most detailers will use UV lamps to dry and start the cross-linking (bonding) process) That last step is particularly difficult for anyone who isn’t working in a clean indoor facility.

And lastly, they’re not inexpensive. You’re talking about a potential four figure number to purchase the coating and for a detailer to do all this work for you.




 Modesta Coatings
Silicon dioxide (SiO2) [: also known as silica, is a chemical compound that is an oxide of silicon. Silica  most commonly found in nature as quartz]

There are a lot of competitive coating on the market; but Modesta Coatings and Opti-Coat Pro are made by professionals for professionals and has rapidly become the benchmark that other coatings are compared to. In the growing industry of vehicle protection, Modesta stands apart from the rest. Its technology is the most sophisticated on the market, aimed for professional use only.

 These coatings are layer-able to produce a thicker top coat if used correctly. Offering effective durability to extreme temperatures, ultra violet (UV) radiation protection and an insane gloss.  These coatings help to protect the paint from all kinds of damage including, wash-induced damages (scratches) oxidation, tree sap, watermarks, salts, acids (including bird and bug excrement) and even permanent ink. Its strong water-repellent properties promote the self-cleaning effects.

Application
It is chemically inert and will not react with the base material. In other words, dirt will not bond to the treated surface, thereby reducing soiling and organic staining. Acid rain and other chemical compounds easily wash off, significantly reducing the hygroscopic nature of surfaces exposed to industrial or environmental pollution.

When a coating is applied to a clean surface, that surface takes on properties that are virtually identical to hardened glass, they are hydrophobic and also exhibit a measurable film thickness. These coatings can also be used to on both glass and wheel surfaces making them much easier to keep clean as well as providing protection.


Hot / Humid environment application
Under these conditions a coating will tend to dry quickly, which may result in a surface with uneven high spots Moisture Cure polyurethane coating binders utilize water molecules from the atmosphere that produces  humidity; this  is what makes the resin set and you  have a limited window of time for application in a high-humidity environment

By using a finger pump spray, as a spray is metered producing an even covering.  Prime the applicator with 4- pumps 

This dispensing method covers the applicator pad evenly and also distributes more product to prevent surface marring on soft paints due to a lack of lubricity. 

A heavier application allows more time to cover a full section instead of working smaller areas Other benefits include being able to ‘level’ the application and to monitor how much you are using as you go and to ensure that you consistently using the same amount per section 

Educating the customer
Modesta is the benchmark SiO2 coating; it’s chemically inert and will not react with the base material. In other words, dirt will not bond to the treated surface, thereby reducing soiling and organic staining. Acid rain and other chemical compounds easily wash off, significantly reducing the hygroscopic nature of surfaces exposed to industrial or environmental pollution.

Properly educating the customer so they understand a coatings possibilities and its limitations, while they offer better protection than waxes or sealants, as well as greater durability they still need to be taken care of properly. Using the proper washing techniques can keep their paint surface swirl free indefinitely.

Teaching them how to use Optimum Technologies (ONR) correctly would go a long way in avoiding paint surface damage like scratches, marring, swirls, and etc. Similar to paint protection film (PPF), it may show some damage from road grit hits but these are within the coating, so the paint underneath is fine. This is also true if the vehicle has been subjected to a damaging wash, the swirls and marring are mostly in the coating itself so the damage comes out more quickly.

There are a lot of competitive coating on the market today and many of them can all be traced back to one or two suppliers. Modesta manufacture all products in house and do not make products for any other brand. In the growing industry of vehicle protection, Modesta stands apart from the rest in a large way. Modesta technology is the one of the most sophisticated coating on the market, for professional use only.

 These coatings are layer-able to produce a thicker top coat if used correctly. Offering effective durability to extreme temperatures, ultra violet (UV) radiation protection and an insane gloss, similar to candy-coat paint.  Modesta coatings help to protect the paint from all kinds of damage including, wash-induced damages (scratches) oxidation, tree sap, watermarks, salts, acids (including bird and bug excrement) and even permanent ink. Its strong water-repellent properties promote the self-cleaning (Lotus effect) effects.

Product
Due to the unique formulation of this type of product, please ensure that you have read and fully understand the purpose and proper application process of before using it.

Neophyte detailers and /or car enthusiasts for whom paint decontamination and paint correction extends beyond their knowledge, experience and/or skill-level to assess, to undertake and complete successfully, or without access to a suitable premise’s i.e. an indoor controlled environment to work in should consider using a different product.  Modesta technology is the one of the most sophisticated coating on the market, for professional use only. The similarities and differences in coatings available on the market are quite striking.

All true coatings are ceramic based, ceramic being a term meaning inorganic. Organics such as sealants are carbon based and as such wear away over time, ceramic in itself is permanent, being inorganic. 
True coatings are characterised by their silicon content (not silicone), and 2 principal variations of silicon are used. The most common is Silicon Dioxide (SiO2) sometimes marketed as glass, quartz or ceramic, and in all cases that’s true.  SiO2 is suspended in a resin in the form of nano particles of Silicon Dioxide, and the resins suspend this in a film over the paint.  It has a melting point of 1,600 °C (2,910 °F; 1,870 K) and on the Mohs scale of hardness is a #7


The other coating system is Silicon Carbide (SiC) Opti-Coat Pro is the only coating available that harnesses the strengths of Silicon Carbide (sometimes referred to as ceramic, industrial diamonds and carborundum. Unlike SiO2 based coatings the SiC-based coating is non-reactive and actually bonds to the paint and maintain the elasticity, unlike a non-bonding coating. The SiC is formed as a chemical reaction in that process, not by having Nano particles of the ceramic floating in a substrate specific resin (like PPG CeramiClear). SiC is superior to SiO2 coatings chemically as it is a continuous film so harmful chemicals cannot permeate and it has a melting point of 2,730 °C (4,950 °F; 3,000 K) and is a #9 on the Mohs scale of comparative hardness. 




Optimum Opti-Coat  is a professionally applied coating that will last for the life of the paint. This coating system is formulated from Silicon Carbide (SiC) and is the only coating available that harnesses the strengths of Silicon Carbide (sometimes referred to as ceramic, industrial diamonds and carborundum. Unlike SiO2 based coatings the SiC based coating actually bonds to the paint and the SiC is formed as a chemical reaction in that process, not by having Nano particles of the ceramic floating in a resin. SiC has a melting point of 2,730 °C (4,950 °F; 3,000 K) and is a 9 on the Mohs scale of hardness.

These coatings seal the paint from moisture and help prevent damage from sunlight, acid rain, bird excrement, bug splatter, environmental fallout, et al. Coatings create a microscopically smooth surface that enhances something called the Lotus Effect the most soil and dirt cannot adhere to, thereby making the surface easier to clean with just water, plus your paint will have reflections that are crisp, bright and reflective.

Organics such as polymer sealants are carbon based and as such wear away over time, ceramic in itself is semi-permanent, as its inorganic. True coatings are characterised by their silicon content (not silicone), and two principal variations of silicon are used. The most common is Silicon Dioxide, sometimes marketed as glass, quartz or ceramic, and in all cases that’s true.  SiO2 is suspended in a resin in the form of nano particles of Silicon Dioxide, and the resins suspend this in a film over the paint.  SiO2 has a melting point of 1,600 °C (2,910 °F; 1,870 K) and on the Mohs comparative  scale of hardness is a 7

Single Stage paint
The primary purpose behind the formulation of coatings (Silica or Ceramic) is to protect Clearcoat paint from the environmental damage and premature failure due to over-polishing.

The problem with single stage paint that they are prone to oxidization, that is to say the resin system that binds the paint becomes compromised very easily. Single stage and clear coat paints are both subject to surface scratches, but the most noticeable problem with single stage is the dullness and fading caused by oxidation. I have however, removed the oxidation by chemical cleaning and / or abrasive polishing prior to applying Opti-Coat (using this product on single stage paint is not recommended by the mfg.) with great results, but I have not done any laboratory or long term testing with Silica or Ceramic coating products on single stage paint.

Care
Properly educating the customer so they understand a coatings possibilities and its limitations, while they offer better protection than waxes or sealants, as well as greater durability they still need to be taken care of properly. Using the proper washing techniques can keep their paint surface swirl free indefinitely.




Hand wash your vehicle regularly with Optimum Car Wash Shampoo or Optimum No Rinse Wash & Shine or Optimum No Rinse Wash & Wax. If your home includes a garage (largely free of household storage), make the time and effort to park your detailed vehicle there every night.

Teaching your clients how to use Optimum Polymer Technologies (ONR) correctly would go a long way in avoiding paint surface damage like scratches, marring, swirls, and etc. Similar to paint protection film (PPF), it may show some damage from road grit hits, but these are within the coating, so the paint underneath is fine. 

This is also true if the vehicle has been subjected to a damaging wash, the swirls and marring are mostly in the coating itself so the damage comes out more quickly.

There are a lot of competitive coating on the market today and many of them can all be traced back to one or two suppliers. Modesta manufactures all products in house and do not make products for any other brand. In the growing industry of vehicle protection, Modesta stands apart from the rest in a large way.

 These coatings can be layered to produce a thicker top coat if used correctly. Offering effective durability to extreme temperatures, ultra violet (UV) radiation protection and an insane gloss, similar to candy-coat paint.  Modesta coatings help to protect the paint from all kinds of damage including, wash-induced damages (scratches) oxidation, tree sap, watermarks, salts, acids (including bird and bug excrement) and even permanent ink. Its strong water-repellent properties promote the self-cleaning (Lotus effect) effects.


Surface friction
Friction force [:  is the force exerted by a surface when an object moves across a surface].

Coefficient of kinetic friction [: is a measure of resistance of thin films that are nominally uniform in thickness]

Coefficient of friction isn't a rigidly defined physical quantity, it's an approximation; if you approximate the force vs. friction as being directly proportional, that proportionality constant is the coefficient of friction, i.e. materials with extreme coefficients of friction, Teflon (low) and rubber (high) are commonly available examples of each.

Scratch resistance - surface roughness is the major factor; not hardness, the rougher the surface, the higher the coefficient of friction and the more the surface is prone to scratches when a towel or some other object is dragged across its surface

Automotive paint surfaces contain microscopic peaks and valleys, much like the profile of a mountain range. These irregularities are known as capillary structures; there may be millions of these defects per square inch. Such a surface has a high coefficient of friction and is relatively easy to scratch

When a coating is correctly applied to this type of surface, it fills in the capillary structures, and the surface takes on properties that are virtually identical to that of uniformly smooth glass, i.e. a uniform thickness and a low coefficient of kinetic friction


This type of surface is also hydrophobic, that is to say it repels moisture, in contrast, a hydrophilic surface is one that absorbs moisture. The potential of a surface to absorb or repel moisture is based on many factors, including: coefficient of friction, temperature, relative humidity, material homogeneity, and static electricity. The lower its coefficient of friction (resistance) the more repellent it is to moisture (Lotus Effect)

Aside from the protection benefits, a coating will also offer better durability, lasting gloss, and an unequalled resistance to dirt and grime, which can easily be rinsed away, making maintenance even easier. Scratch resistance is directly related to higher cross-link density and elasticity of the coating network as well as the surface’s friction resistance.

Coating Hardness:

Hardness: [In materials science, hardness is the characteristic of a solid material expressing its resistance to permanent deformation. There are three principal operational definitions of hardness: Scratch hardness, Indentation hardness, Rebound or dynamic hardness]

It is important to note that manufacturer-approved paint suppliers vary by country as each country (and even province/state) has their own environmental laws they must adhere to.
Ten years ago PPG’s CeramiClear clear coat was a product that Mercedes-Benz co-developed and introduced, and at that time it was the first clear coat to utilize nanotechnology for higher scratch resistance and reduced paint fade. Since then there have been several advancements and changes to clear coat technology as well as the overall paint process during vehicle production at the factory, not to mention changes in environmental regulations for chemical compositions used by the factory’s paint suppliers

Most factory paint does not contain ceramic particles for hardness; there is more advanced technology today utilized to ensure hardness of the clear coat and the composition varies by application and curing temperature, but typically consists of acrylate-type resins and isocyanate-type cross-linkers.

Modern clear coat urethane even though they are harder than lacquer paints, they still scratch more easily. And because they tend to be harder it's more difficult and time consumer to remove swirls and scratches. This is the main reason to take vendor claims of ‘provides 9H hardness ‘for what it is – totally irrelevant. 

So how can a dense (hard) clear coat be so easily scratched?
Force acts through a body that has a surface area; if the surface area is really small while maintaining an equal force, the pressure becomes astronomical and the object under pressure capable of penetrating the surface of an otherwise tough material. (Newton's third law of motion)
That’s why a micro fine thread that is twice as fine as silk and a 100 times finer than a human hair, in an otherwise soft towel will scratch your paint. And the same reason a mosquito can penetrate a rhino hide with its proboscis (stinger).

Silicon dioxide
A common element in a coating formula, Silicon dioxide (SiO2) also known as silica, is a chemical compound that is an oxide of silicon. Silica is most commonly found in nature as quartz.
Often misnamed as a glass coating, however glass is an amorphous (non-crystalline) solid material which is often transparent. Of the many silica-based glasses that exist, ordinary glazing and container glass is formed from a specific type called soda-lime glass, composed of approximately 75% silicon dioxide (SiO2), sodium oxide (Na2O) from sodium carbonate (Na2CO3), calcium oxide, (CaO), and several minor additives.

What is Nanotechnology as it relates to Detailing?
The science of nanotechnology; the creation, organization, or manipulation of materials, devices, or systems at the nanometre level Nanotechnology, Nano particles or Nano structures, exactly what are they and how do they relate to detailing?

Most of these coatings are not true nanotube/tubule technology. This would cause a serious health concern for all of those - not to mention be ridiculously expensive. The context that “nano" (as related to detailing) is only as a relative size indicator merely to identify a micro sized particulate. They are sub-micron particles that form a clear thin film of tightly packed nano particles forming an extension of the surface. The particles are up to a 1000 times denser which makes for an ultra-durable hard wearing surface.

Technically most detailing product particulates are not nano metre in size, although they are extremely small, as the term ‘nano’ adequately describes. Single-component coatings interlace on a molecular basis and form an extremely durable protective layer on the paint surface provided they are applied properly.

The significance of a nano-coating is its micro-sized particles that can form a very tight bond with the surface of most materials; including glass, paint, plastic, rubber, aluminium, chrome, stainless steel and fabrics.

These materials will have surface imperfections i.e. peaks and valleys, micro-fissures when viewed under high magnification. These undulations allow a nano-coating polymer to form a tight molecular bond (much like a printer’s powdered ink when poured over paper that has writing indentations on it) with the surface it’s applied to.

Paint Surfaces
Automotive paint surfaces contain microscopic peaks and valleys, much like the profile of a mountain range. These irregularities are known as capillary structures; there may be millions of these defects per square inch. Contaminants such as fine dirt, minerals, and pollutants are drawn into the voids where they are extremely hard to remove.

The filling of the capillary structures with micro particles produces a hydrophobic surface. (A hydrophobic surface is one that repels moisture.) In contrast, a hydrophilic surface is one that absorbs moisture. The potential of a surface to absorb or repel moisture is based on many factors, including: temperature, relative humidity, material homogeneity, and static electricity. Surface roughness is also a major factor; the rougher the surface, the higher the spreading rate or attraction for water. The smoother the surface, the more repellent it is to moisture (Lotus Effect).

The significance of a micro coating is its small particle size that can form a very tight bond with the surface of most materials; including glass, paint, plastic, rubber, aluminium, chrome, stainless steel and fabrics, will have surface imperfections i.e. micro-fissures when viewed under high magnification. These undulations allow a micro coating to form a tight molecular bond (much like a printer’s ink when poured over paper that has writing indentations on it) with the surface it’s applied to This level surface also improves paint surface clarity and reduce light scattering, providing improved light reflectance (LRV)

The cause of self-cleaning properties (Lotus Effect) is the hydrophobic water-repellent double structure of the surface. Dirt particles are picked up by water droplets due to the micro and nanoscopic architecture formed by a coating is one in which the paint surface fissures or gaps are filled, which minimizes the droplet's adhesion to that surface.  This enables the contact area and the adhesion force between surface and droplet to be significantly reduced resulting in these treated surfaces become hydrophobic that resists road dirt, grime and etc.

It is therefore highly water repellent, which enables less effort during the cleaning stages and optimum protection to the paintwork, glass, alloys, fabric and trim. The high surface tension of water causes droplets to assume a nearly spherical shape, since a sphere has minimal surface area, and this shape therefore has least surface energy. On contact with a surface, adhesion forces result in wetting of the surface. Either complete or incomplete wetting may occur depending on the structure of the surface and the fluid tension of the droplet

Micro technology coatings form a very tight matrix chain-link a micro structure that comprises a clear thin film of tightly packed nano particles forming an extension of the surface. These very dense particles are both a very strong bond and one that is not easily breached by chemicals or detergents. They also improve paint surface clarity and reduce light scattering, providing improved light reflectance

Through self-organizing anti-adhesion components, the micro structure forms an invisible barrier similar to glass. They form a bond by lodging themselves into the micro pores of the paint forming an anchored foundation and then this foundation is built upon to form the nano particle matrix. This is why a clean and dry, oil-free (micro pore) surface is so important. Only the micro structure remains on the sealed surfaces, while the water evaporates.

Micro technology offers superior durability, hydrophobicity, surface hardness and scratch resistance, resistance to environmental contaminants, works like a clear coat in providing ultra violet (UV) and heat radiation protection without colour change (yellowing) or oxidation and easier maintenance, simply rinsing with plain water results in a clean surface without loss of gloss; these products are having a profound impact and radically change auto detailing

Coating Tests
Pencil hardness test is only one of many tests (see also Bibliography) that are done to evaluate a coating's performance. Other tests are abrasion, reverse impact resistance, direct impact resistance, cross-hatch adhesion, oxidation, gloss retention, UV resistance, yellowing, blistering, drying times, chemical/solvent resistance (using both the rubbing and spot/time tests), salt spray resistance, humidity resistance, acid and caustic resistance, the VOC and HAP contents, and so on.

Does paint density (hardness) affect its scratch resistance? - many coating products claim an obtained surface (Pencil) hardness of 9H but this has little if anything to do with scratch resistance. Scratch resistance can be related to higher cross-link density and elasticity of the coating network as well as the surface’s friction resistance.

Some Nanotechnology Coating products

·             AQuartz is an inorganic silica / silicon dioxide
·             DuPont's SupraShield™, PPG's Optech™ and CeramiClear™ are all inorganic silica coating
·             Gtechniq is an inorganic silicate crystallization compound
·             Modesta is an inorganic Silicon dioxide (SiO2)
·             Nanolex is an inorganic, solvent-based nanostructure coating
·             Opti-Coating Pro is a silicon carbide (SiC) grains of silicon carbide are bonded together by sintering to form a very hard ceramic




Hydrophobicity

Definition of Water repellence (hydrophobicity)-

Hydrophobic surface [: The requirements for a self-cleaning hydrophobic surface are a very high static water contact angle θ, the condition often quoted is θ>160°, and a very low roll-off angle, i.e. the minimum inclination angle necessary for a droplet to roll off the surface]

Hydrophobicity [: the property of being water-repellent; tending to repel and not absorb water is determined by the contact angle]

A hydrophobic surface is one that repels moisture. In contrast, a hydrophilic surface is one that absorbs moisture. The potential of a surface to absorb or repel moisture is based on many factors, including: temperature, relative humidity, material homogeneity, and static electricity. Surface roughness is also a major factor; the rougher the surface (see also surface contamination) the higher the spreading rate or attraction for water. The smoother the surface, the more repellent it is to moisture.

The lotus effect [: refers to self-cleaning properties that are a result of very high water repellence (super- hydrophobicity)]

As exhibited by the leaves of the lotus flower, Dirt particles are picked up by water droplets due to the micro-architecture on the surface, which minimizes the droplet's adhesion to that surface

Young–Laplace equation
The contact angle can also be related to the work of adhesion via the Young–Dupré equation:
Where is the solid - liquid adhesion energy per unit area when in the medium V.


Contact angle
Young–Laplace equation - Contact angle [: is the angle measured through the liquid, where a liquid/vapour interface meets a solid surface. It quantifies the wettability of a solid surface by a liquid via the Young–Laplace equation]

The contact angle is the angle, conventionally measured through the liquid, where a liquid–vapour interface meets a solid surface. It quantifies the wettability of a solid surface by a liquid via the Young equation. A given system of solid, liquid, and vapour at a given temperature and pressure has a unique equilibrium contact angle. A contact angle is conventionally measured through the liquid, where a liquid–vapour interface meets a solid surface. It quantifies the wettability of a solid surface by a liquid via the Young equation. A given system of solid, liquid, and vapour at a given temperature and pressure has a unique equilibrium contact angle. However, in practice contact angle hysteresis is observed, ranging from the so-called advancing (maximal) contact angle to the receding (minimal) contact angle.

Contact angle measurement provides a simple way to determine the level of surface protection. The formation of large, closely spaced water droplets demonstrates that moisture is effectively prevented from being absorbed (a hydrophobic surface) into the surface profile. The classification of water droplets on a hard surface is known in industry as a “water break test” or American Society for Testing and Materials (ASTM) F-22. This test is used extensively in the industry to check surface cleanliness.

The size, shape, and height of the water droplets are measured by their contact angle. Contact angle is figured by a straight line that starts at the base of the droplet and travels along its outer surface to the break-off point. The measurement between this line and the surface determines the contact angle

If the liquid molecules are strongly attracted to the solid molecules then the liquid drop will completely spread out on the solid surface, corresponding to a contact angle of 0°. Surfaces with a contact angle A less than (> A 90°) angle is referred to as hydrophilic and those with an angle of more than (A 90°<) angle as hydrophobic. Some plants show contact angles up to 160° and are called super-hydrophobic meaning that only 2-3% of a drop's surface is in contact. Plants with a double structured surface like the lotus can reach a contact angle of 170° whereas a droplet’s actual contact area is only 0.6%. All this leads to a self-cleaning effect.

Wettability:

[: Wettability is the tendency of one fluid to spread on, or adhere to, a solid surface in the presence of other immiscible fluids]

Wetting is the ability of a liquid to maintain contact with a solid surface, resulting from intermolecular interactions when the two are brought together. The degree of wetting (wettability) is determined by a force balance between adhesive and cohesive forces. Relative ability of a fluid to spread readily and uniformly over the surface of another fluid or solid, forming a thin, continuous film. Fluids with high surface tension (such as mercury) have little or no wetting ability; those with low surface tension (such as petroleum solvents) have high wetting ability. Fluids with medium surface tension (such as water) acquire greater wetting ability with the addition of a wetting agent (surfactants).

Viable Paint Surface Protection
Water forming spheres (beading) on a paint surface are caused by an applied product ‘contact angle’ (See also surface tension). When you wash your car, watch carefully as the water is rinsed away. When rinsing with a steady flow of water it should sheet off of the paintwork leaving behind the odd water sphere. If the water lies in large flat regions, and doesn't sheet off the paintwork then it may mean that protective layer is no longer viable.

Contaminant molecules adhere to the surface, these molecules change the balance of forces and reduce the net inward force. Since the net inward force is related to the surface energy, it’s reduced by contaminants.  Brake and rail dust as well as airborne dust, pollen, road traffic film and etc. will all negatively impact the surface energy  

Many products, like a high alkaline shampoos, or a product that contain surfactants, which ultimately lower the surface tension and negatively impact the surfaces hydrophilic properties.
Be cognizant that water spheres on a paint surface is not an indication of actual paint protection, the presence of small, tall water spheres when it rains shows that there is a wax or polymer layer present, while larger flatter spheres (on a clean surface) is indicative there is no longer a viable paint protection layer present (for coatings see surface energy paragraph)

Roll-off
Lotus effect [: refers to self-cleaning properties that are a result of very high water repellence (super- hydrophobicity), as exhibited by the leaves of the lotus flower]

Repellant [: able to repel a particular thing; impervious to a particular substance]

Roll off of dirt particles with a reduced contact area are encapsulated by water droplets and are easily cleaned off the surface. If a water droplet rolls across such a contaminated surface the adhesion between the dirt particles and the water droplet is very much reduced and the dirt is easily removed from the surface

Surface energy [: defined as the excess energy at the surface of a material compared to the bulk or the work per unit area done by the force that creates the new surface]

In dealing with liquids, it is more usual to use the idea of surface tension rather than surface energy, even though they refer to the same dimensional quantity. The net inward force on the surface of a liquid makes the surface act as if it was an elastic skin that constantly tries to decrease its area.

Surface Tension
[: cohesive forces among liquid molecules are responsible for the phenomenon of surface tension. In the bulk of the liquid, each molecule is pulled equally in every direction by neighbouring liquid molecules, resulting in a net force of zero]

The molecules at the surface do not have the same molecules on all sides of them and therefore are pulled inwards. This creates some internal pressure and forces liquid surfaces to contract to the minimal area, which produces spheres of rain water (beading) on a waxy surface, such as a leaf. Water adheres weakly to wax and strongly to itself, so water clusters into drops. Surface tension gives them their near-spherical shape, because a sphere has the smallest possible surface area to volume ratio. 

Surface tension is responsible for the shape of liquid droplets or spheres. Although easily deformed, droplets of water tend to be pulled into a spherical shape by the imbalance in cohesive forces of the surface layer. In the absence of other forces, including gravity, drops of virtually all liquids would be approximately spherical. The spherical shape minimizes the necessary "wall tension" of the surface layer according to the Young–Laplace equation, describing pressure difference over an interface in fluid mechanics

Surface energy [: is the elastic tendency of liquids which makes them acquire the least surface area possible] It has the dimension of force per unit length, or of energy per unit area. Surface energy and surface tension are equivalents, but when referring to energy per unit of area, people use the term surface energy, which is a more general term in the sense that it applies also to solids and not just liquids. 

In order to successfully form a continuous coating, the liquid should be able to wet the surface of the material. Wettability depends on one specific property of the surface: surface energy. The surface energy of the solid substrate directly affects how well a liquid wets the surface. To achieve good wettability, the surface energy of the substrate needs to exceed that of the surface tension of the liquid by around 2 - 10 mN/m (Dynes). The Dyne level reflects the surface wettability - the higher the Dyne level, the better the wettability/adhesion.



Coating Viability
Surface energy (interface energy) [: in the physics of solids, surfaces must be intrinsically less energetically favourable than the bulk of a material (the molecules on the surface have more energy compared with the molecules in the bulk of the material]

Surface tension has the dimension of force per unit length, or of energy per unit area. For a liquid, the surface tension (force per unit length) and the surface energy density are identical. Water has a surface energy density of 0.072 J/m2 and a surface tension of 0.072 N/m the two are equivalent. But when referring to energy per unit of area, people use the term surface energy, which is a more general term in the sense that it applies also to solids and not just liquids

To obtain optimum adhesion, it is necessary to increase the surface energy of the substrate to just above that of the material to be applied. For optimum adhesion of a coating on various substrates, it is necessary to obtain a high surface energy. Determining the surface energy can be achieved by measuring contact angle or by use of Surface Energy Test Liquids or Pens (Dyne level testing).

This form of measurement is based on the ISO method for measuring the surface energy of polyethylene film. Surface energy may be defined as the excess energy at the surface of a material compared to the bulk.  Every solid surface has a specific and measurable surface energy.  The unit of measurement used is the Dyne/cm² or mN/m.

When the Dyne level test liquid is applied to the surface, the liquid will either form a continuous film on the surface or pull back into small droplets. If the Dyne test fluid remains as a film for 3 seconds, the substrate will have a minimum surface energy of that fluid value, expressed in N/m (Dynes). Should the Dyne test fluid reticulate or draw back into droplets in less than 1 second then the surface energy of the substrate is lower than that of the fluid itself. To test the viability of a coating requires measuring the surface energy (surface tension).

Using a Dyne Test Pen will measure the surface tension and identify whither the coating is still viable, which requires a surface tension of 38mN/m or higher.
Measure the surface energy by using slight pressure to draw the Dyne QuickTest Pen tip across the coated surface. If the ink lines shrink or bead within 1-2 seconds, then the surface protection is degrading as the surface energy level has dropped to less than 38 Dynes. If the ink lines remain as marked and do not shrink, then the test sample surface protection is still viable as the coating has a surface energy of 38 Dynes or higher.

Dyne QuickTest Pen - http://www.dynetechnology.co.uk/measurement-equipment/quick-test-pens/

Product Application
Be cognizant that for a coating product to reach its full potential; that is to say the correct contact angle, durability and optimum cross-linking it imperative that you provide a ‘clean’ surface. Prior to application both above and sub-surfaces should be decontaminating, polishing lubrication (oils, polymer (silicones) and wax) system should be removed

Use the appropriate personal protection equipment (PPE) an approved mask (Consult the current 3M Respiratory Selection Guide for additional information or call 1-800-243-4630 for 3M technical assistance) nitrile gloves and safety glasses as a minimum.

Due to the construction of micro fibre towels, they comprise a hydrophobic Polyester (a scrubbing fibre) which also gives the material strength and durability and a hydrophilic Polyamide (an absorbing fibre) that is tremendously absorbent and quick drying. This nylon hybrid is created during weaving to create microscopic loops, which form a network of tiny hooks, scrubbing away dirt and grime.  The nature of this yarn is that it is an absorbent; the reason polyester appears to absorb liquids is the many thousands of micro fibres that collectively encapsulate liquids.

1)       Dr Joe dedicated Lint-Free 100% Cotton Surgical Towels, that have a lint free, tight cotton herringbone weave and a thread count of 170 per square inch, which is ideal for hard surfaces as they have more ‘grip’ than micro fibre towels and helps to spread the coatings evenly. Fold the towel in half and then half again.

2)       The coating can also be applied with a lint-free and non-abrasive microfiber suede cloths (very low nap), which will evenly spread the coating as opposed to absorbing it. Edgeless optical grade suede weave Use a fresh cloth with an applicator block to help you lay down the perfect application of liquid coatings and other protection products. The Rag Company Detail Master™ Pro but the major disadvantage of this type of application is the coating dries and solidifies to glass, which means you need 5- 8 towels that will be discarded after use.

My preferred application method is to use base coating (P-01A) applied with a rotary machine polisher and apply the coating with a spray gun as I feel this gives a consistent thickness and coverage. The coating can be applied with a micro fibre towel but the major disadvantage of this type of application is the coating dries and solidifies to glass, which means you need 5- 8 towels that will be discarded after use.

Surface Drying and Curing Coatings
All infrared energy is part of the same electromagnetic spectrum that continually surrounds us. X-rays and ultraviolet energy waves are below the visible light spectrum, and infrared and short-wave radio waves are above the visible spectrum.

1.      Long-wave infrared isn’t very desirable for curing automotive coatings because it tends to heat the top of the paint film rather than penetrate through the paint to the substrate.
2.      Medium-wave infrared will penetrate through the paint film and heat the substrate. By warming the paint from the bottom up, the solvents are pushed out into the air. If you heat the top surface first, the solvents are trapped inside the paint film

3.      Short-wave infrared also heats the substrate, not the surface, but penetrates faster than medium-wave. Some short-wave units have a ramp-up setting that feeds the energy onto the surface gradually. Medium-wave units don’t need a ramp-up restriction since they take a few minutes to reach full heat.

What temperature will an infrared heater reach?
There are a number of considerations that may affect the final product temperature. Standard portable automotive curing lamps are designed to accelerate the curing of any liquid coating that will eventually air-dry on its own. When used between 18″ and 36″ from the surface of the drying substrate, an Infratech heater will generally reach target temperatures from 140° F to 200° F. These variances depend upon a range of factors, including actual heater model, size of the area to be dried, product mass relative to surface area, heater distance from the product, exposure time and ambient conditions.

After the coating process I would recommend the use of Infrared Cure lamps to crosslink the coating at a temp of 60.O C for 15 minutes per panel. Infrared radiation to the coating will enable the coating to cross link and start the curing process, infrared heat will also aid product overall drying, improving both gloss and hardness. When large surface area need to be heated, infrared lamps are often used in banks. Infrared heat lamps are commonly incandescent bulbs which are able to produce infrared radiation.

This process drastically increases the coatings hardness and protection abilities as well as its shine and gloss. It takes approx. three weeks before the coating is completely cured, but rest assured it is completely safe to drive during this period. When large surface area need to be heated, infrared lamps are often used in banks. Infrared heat lamps are commonly incandescent bulbs which are able to produce infrared radiation.

Product curing (cross-linking) and drying as per Manufacturers recommendations using infra-red lamp(s) Allow approx.24 hours in a moisture / dust free environment drying time. A further 28 days is required before the coating is fully cross-linked

All infrared energy is part of the same electromagnetic spectrum that continually surrounds us. X-rays and ultraviolet energy waves are below the visible light spectrum, and infrared and short-wave radio waves are above the visible spectrum.

1.       Long-wave infrared isn’t very desirable for curing automotive coatings because it tends to heat the top of the paint film rather than penetrate through the paint to the substrate.

2.      Medium-wave infrared will penetrate through the paint film and heat the substrate. By warming the paint from the bottom up, the solvents are pushed out into the air. If you heat the top surface first, the solvents are trapped inside the paint film

3.      Short-wave infrared also heats the substrate, not the surface, but penetrates faster than medium-wave. Some short-wave units have a ramp-up setting that feeds the energy onto the surface gradually. Medium-wave units don’t need a ramp-up restriction since they take a few minutes to reach full heat

Drying / Curing

Coating drying and curing times vary according to temperature, humidity and air movement. Raising the surface temperature not only drives out the solvent, making the coating dry to the touch, but it promotes the chemical cross link of the coatings components and the paint surface. The faster those two components cross-link, the sooner the work can be delivered.  IR (infrared) dry times can be reduced by 60 percent over ambient, unassisted dry times when portable heat is carefully applied.
Drying and curing (cross-linking) are two very different processes:

·         Drying - use of infra-red lamps is highly recommended. IR drying in a moisture / dust free environment.
·         Curing – the product will be fully cured / hardened (subject to environmental conditions experience) in approx. thirty days

      Because of the thickness and hardness of most coating products I would recommend you use a “wet application” method to ensure proper formation of a glass coat over the entire vehicle. Once this process is completed use Infrared Cure Lamps to cure the coating to the paint surface (curing at 155.0F for 15 - 25 minutes (dependent upon type of IR lamp used) further increasing its strength and durability. Moisture should be avoided for between 12-24 hours after drying

Shortwave Infrared Curing Lamp

     Generally speaking, the higher the temperature, the shorter the wavelength produced. The different between the three types- long, medium and short, is in the depth of penetration through the paint film (in automotive applications) and excitement of the molecular structure. The advantage of using infrared is that only heats objects that are placed in its path, directly focusing energy where it's needed. Infrared equipment causes molecular excitement both in the paint and in the substrate which in turn causes heat to pass back through the coating via conduction. The use of shortwave infrared is in fact triggering a two-way conduction from the substrate and it is this effect that produces such good through curing.

Shortwave produces high temperature the dramatically accelerate the curing/drying process, unlike traditional method, the cured paint could not be skinned, trapping solvent that will produce solvent pop (a pinhole effect) to the finish. Another benefit is that infrared is much more efficient than convection, and it is this combination of fast, high quality curing with low running costs. 

. What temperature will an infrared heater reach?

There are a number of considerations that may affect the final product temperature. Standard portable automotive curing lamps are designed to accelerate the curing of any liquid coating that will eventually air-dry on its own. When used between 18″ and 36″ from the surface of the drying substrate, an infrared heater will generally reach target temperatures from 140° F to 200° F. These variances depend upon a range of factors, including actual heater model, size of the area to be dried, product mass relative to surface area, heater distance from the product, exposure time and ambient conditions.

Coating Maintenance
Many people have the incorrect impression that paint coatings are a “no maintenance required” type of product.  This is simply not true.  Routine washing is crucial.  As your coating becomes covered with dirt and contamination, you will notice a decrease in hydrophobic properties. It’s important to remove any surface contaminates on a regular basis with a car wash concentrate that will not leave gloss enhancers or surfactants behind due to a coating ‘roll off’ washing and drying the paint surface is very easily accomplished
The normal car wash concentrates mostly contain surfactants and alkaline additives. They work by breaking down surface tension and wetting the surface to facilitate soil removal by flushing. With many of the newer coatings traditional car wash solutions, especially at their normal extreme dilutions.
Use a specially formulated product like Optimum ONR or Modesta H-05 Shampoo– specifically formulated for hydrophilic coatings. This special shampoo removes dirt and restores/prolongs the coating’s original hydrophobicity. This is an ideal coating maintenance shampoo
Dry surfaces with a waffle weave (pique) towels to ensure zero marring to the paint surface

Summary
Polish the paint surface to remove (without removing too much clear coat) any surface imperfections as this product cures to become optically clear and will highlight any surface defects. It has always puzzled me why people over-polish their car paint and cause the paint to fail prematurely; we all have seen examples of clear coat failure. A coating is the most effective way to avoid premature failure of clear coats.

Coatings offers superior durability, hydrophobicity, surface hardness and scratch resistance, resistance to environmental contaminants and works in a similar way to a clear coat in providing ultra violet (UV) and heat radiation protection without colour change (yellowing) or oxidation and easier maintenance, simply rinsing with plain water results in a clean surface without loss of gloss. I think these products will have a profound impact and radically change auto detailing

Bibliography
1.           Royal Society of Chemistry (RSC) Library & Information Centre
2.           Glossary of Chemical Terms - Faculty of Chemical Technology
3.           Basic Concepts of Nanotechnology, History of Nano-Technology, News, Materials and Potential Risks
4.           Lotus-inspired nanotechnology applications, B. Karthick1 and Ramesh Maheshwari
5.           SpecialChem4 Polymers
6.           Macromolecular Chemistry and Physics
7.           European Coatings Handbook 2nd Edition, by Brock, Groteklaes, Mischke
8.           Bayer Material Science, Automotive eNewsletters (Coating, Adhesives, and Specialties)
9.           American Society for Testing and Materials (ASTM) publications - http://www.astm.org/Standard/standards-and-publications.html
10.       ASTM D1014 - 09 Standard Practice for Conducting Exterior Exposure Tests of Paints and Coatings on Metal Substrates
11.       Contact Angle and Wetting Properties - Yuehua Yuan and T. Randall Lee



Relevant Articles
1.      Reference Resources used for Polymer Articles - http://togwt1980.blogspot.co.uk/2015/07/reference-resources-used-for-polymer.html

2.      Paint Coating Safety Concerns - http://togwt1980.blogspot.co.uk/2015/06/paint-coating-safety-concerns.html

3.       Paint and Related Coating Standard Testing and Certification- http://togwt1980.blogspot.co.uk/2015/07/paint-and-related-coating-standard.html

4.      Silica Coatings: Protection from Potential Health Hazards - http://togwt1980.blogspot.co.uk/2015/03/silica-coatings-protection-from.html

5.      Do Water Spheres (Beads) equal Durability? - http://togwt1980.blogspot.co.uk/2015/07/do-water-spheres-equal-durability.html

6.      The chemical similarities and differences in Modesta and Opti- Coat Pro Coatings –              http://togwt1980.blogspot.co.uk/2015/06/the-chemical-similarities-and.html
7.      Silica Coatings Application Methods - http://togwt1980.blogspot.co.uk/2015/04/silica-coating-application-method.html

8.      Modesta Coating - http://togwt1980.blogspot.co.uk/2015/06/modesta-coating.html




12.  Is your paint coating still viable? - http://togwt1980.blogspot.co.uk/2015/06/is-your-paint-coating-still-viable.html

Current Information
I hope these articles are informative. The information in this article is based on the current status of the technical development as well as our experience with the products.
I would appreciate it if you would share these articles as it helps other detailers further their knowledge.

As always if you have questions, I’ll do my best to answer; bear in mind the only stupid questions are the one that was unasked. Questions and/ or constructive comments are always appreciated

Foot Note:
I carried out extensive laboratory testing of coatings utilizing standard lab protocols, this entailed chemical analysis with a mass spectrometer, heat, acid and ultra violet radiation resistance, surface hardness and hydrophilic properties.

The Mass spectrometry analysis showed many similarities between some brands, which not surprisingly would suggest relabeled products.

The few, just let’s say unique, products although using completely different chemicals in their formulation exhibited outstanding results

Filing a patent on a chemical formulation is extremely difficult and would not solve the problem as changing just one component would make the patent void. Change is what R&D is all about, and besides relabeled product in the final analysis results in more sales.

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