What Is Photocatalytic Paint?
Photocatalytic paints are paints made from titanium dioxide or titanium dioxide.
They are typically used to paint the exterior walls of buildings. Exposure to light or ultraviolet rays after application exerts a self-cleaning effect.
Uses of Photocatalytic Paints
Because of its self-cleaning effect, photocatalytic paint is often used to paint exterior walls that are particularly difficult to maintain on a regular basis.
Fluoropolymer paints, which are high-grade paints, have a durability of 15 to 20 years, and photocatalytic paints have the same durability. Therefore, it is sometimes used for high-rise buildings where the number of maintenance cycles needs to be kept low. Because it is a high-quality paint, the initial investment is high, but the advantage is that running costs can be kept down.
Principle of Photocatalytic Paints
The main raw materials for photocatalytic paints are titanium dioxide and titanium dioxide. After photocatalytic paint is applied, exposure to light or ultraviolet light causes a separation of electrons and holes (excited state) within the titanium dioxide or titanium dioxide contained in the paint. Because electrons are ejected from the photocatalytic paint, the surface of the photocatalytic paint is positively charged.
This positively charged surface has a very strong oxidizing power and decomposes water adhering to the photocatalytic paint surface to produce hydroxyl radicals. These hydroxyl radicals are extremely unstable substances. Therefore, they combine with organic compounds, organic chemicals, exhaust gases, and other pollutants that are the source of dirt on the wall surface, decompose them, and provide a self-cleaning effect that prevents the adhesion of dirt.
On the other hand, the electrons emitted from photocatalytic paint undergo a reduction reaction with oxygen to produce a superoxide anion. This superoxide anion is also a substance with very strong oxidizing power. It binds to organic compounds, organic chemicals, exhaust gases, and other pollutants, decomposing them and preventing the adhesion of dirt, thereby achieving a self-cleaning effect.
In addition, photocatalytic paint is characterized by its highly hydrophilic surface. Therefore, even if rain or other water adheres to a wall surface coated with photocatalytic paint, it will not form water droplets, but will instead run off. The above-mentioned decomposed organic compounds, organic chemicals, dust, and other substances are washed away with the rain, providing a self-cleaning effect. Titanium dioxide and titanium dioxide are safe substances, and photocatalytic paints are environmentally friendly.
Other Information on Photocatalytic Paints
1. Ultraviolet Photocatalytic Paint and Visible Light Photocatalytic Paint
There are two types of photocatalytic paints: ultraviolet photocatalytic paints, which provide self-cleaning effects with ultraviolet light, and visible photocatalytic paints, which provide self-cleaning effects with visible light. Conventionally, ultraviolet photocatalytic paints have been widely used. However, UV photocatalytic paints have the disadvantage that the self-cleaning effect cannot be obtained without UV light.
Visible light photocatalytic paints are effective not only with ultraviolet light but also with visible light, and their functionality is superior to that of ultraviolet light photocatalytic paints. Therefore, the visible light type is generally selected unless it is used for special applications.
2. Photocatalytic Paint for Interior Applications
In recent years, photocatalytic paints for interior use have also become available. When photocatalytic paints are used for interiors, the same self-cleaning effect can be achieved as with photocatalytic paints for exterior walls. As a result, it has antifouling, antibacterial, and antiviral effects, and can also decompose odor substances.
It can control bothersome odors from pets and garbage, and clean the air. It also prevents the formation of mold and is suitable for places where water is frequently used.
3. Price of Photocatalytic Paint
Photocatalytic paint is usually applied by a specialized contractor because the application process is finely divided and requires expertise. For example, the cost of painting an exterior wall is said to be “15 – 25 USD” per square meter.
Silicon paint, which is often used for exterior walls and costs approximately “15 – 25 USD” per m2, and fluorine paint, which is considered somewhat more expensive, costs about “25 – 35 USD” per m2. The initial cost tends to be higher when painting with photocatalytic paint.
It is important to make a comprehensive decision, taking into consideration the service life and effectiveness, whether for exterior wall painting or interior decoration.