As a former auto-body technician, detailer, and car wash operator, I’ve been following along with interest the development of self-cleaning paint.
By Robert Roman
Self-cleaning paint belongs to a class of materials with the inherent ability to prevent any debris from adhering to a surface in a variety of ways. For example, Nissan began to experiment with a self-cleaning paint called Ultra-Ever Dry in 2014 on both its Note and EV Leaf models.
The paint was developed at the Nissan Technical Center in the United Kingdom in conjunction with nanotechnology firm, Nano Labs.
According to a press release, Nissan has no current plans to use the paint as standard equipment but will continue to consider the coating as a future aftermarket option. In other words, proof of concept for self-cleaning paint, at least for automotive use, is still in the works.
Nevertheless, considerable pro-gress is being made with self-cleaning technology. Self-cleaning surfaces can be divided into three categories: super-hydrophobic, super-hydrophilic, and photo-catalytic. For example, Nissan’s paint is both hydrophobic, which means it repels water, and oleophobic, which means it repels oil.
Haruna Singapore Pte Ltd manufactures a super-hydrophilic paint for commercial buildings that contains nano particles of titanium dioxide. When this paint is exposed to the sun or ultraviolet light, any organic substances on the surface decompose with the oxidative properties contained in the paint’s coating. When the paint comes in contact with water, the water forms an even layer and easily washes away any surface accumulation of stains, dirt, and dust.
One of the main benefits of the self-cleaning paint is the lower cost of maintenance. For example, the average cost to clean the exterior of a commercial building is $0.75 per square foot. This includes chemical and manpower and excludes energy and water.
Consequently, the potential benefit to consumers from owning a car coated with self-cleaning paint is obvious as is the potential consequences to car wash operators.
The principal constraint that prevents self-cleaning paint from being widely used is sensitivity to mechanical loads, which damages the effect. Also, the paint has a slightly matt finish.
Arguably, an interim step towards self-cleaning car paint will be easy-to-clean surfaces. That does not mean the surface never needs to be cleaned but rather that the amount of cleaning required compared to that of traditional products can be greatly reduced.
For example, instead of cleaning cars with multiple brushes and aggressive chemicals, several firm jets of water would be sufficient to remove dirt and grime from an easy-to-clean surface.
Currently, the best the car wash industry can deliver are water repellents and compounds that contain a little wax that impart hydrophobic properties that may last several weeks.
Experience shows these products do make it slightly easier to clean a vehicle the next time, but certainly a lot more than several firm jets of water is needed to do so.
Hand wax and paint sealant provide more in terms of longevity and making re-washing easier. However, if product innovation is any indication, maybe an easy-to-clean car surface produced at commercial car washes isn’t out of the question in the future.
For example, consider Rain-X glass treatment. Many years ago, Rain-X was sold in auto parts stores in a small squeeze bottle. You would apply some of it on a pad, wipe on the glass, let it dry to haze, and then buff it off with a clean, dry cloth. Next, Rain-X was conveniently formulated as windshield washer fluid. Today, Rain-X makes windshield wipers that impart the water repellent effect directly to the glass.
Consequently, motorist now have a reason not to buy glass treatment at the car wash.