Thin-film Coating Technique

Generally speaking, Photocatalyst materials own two main characteristics: One is its chemical property, which means its strong oxidizing power that enables Photocatalyst to decompose organic matters and to perform anti-bacterial and deodorizing functions. The other is its surface property, or the “super-hydrophilicity”, such hydrophilic property allows water molecules to form a thin layer on the Photocatalyst-processed surface and hence adds dirt-prove and self-cleaning effects.
However, it is almost impossible for a Photocatalyst product to achieve both properties to the extreme at the same time. If a Photocatalyst product is designed for anti-bacterial, anti-molding and deodorizing applications, then the Photocatalyst material must be rich in concentration and be properly fixed to ensure high decomposing power, otherwise it may take days and hours to breakdown odor molecules and microbes, which is not practical for daily purpose. However, when the concentration of Photocatalyst is increased to perform a strong oxidizing power, it becomes impossible to process Photocatalyst by thin-film coating technique, and its super-hydrophilic property will be poor. To guarantee the super-hydrophilicity, Photocatalyst of a specific ratio must be fixed on the surface of the object by thin-film coating technique. By this method the super-hydrophilic property of Photocatalyst-processed surface can be easily observed even by naked eyes, but it now only has limited oxidizing power and therefore can not decompose a great amount of organic matters in a short period.

Hydrophilicity and Hydrophobicity

When water molecules make contact with the surface of an object, either hydrophobic or hydrophilic properties will be shown with the surface characteristics of the object. For example, after the surface of an automobile is waxed, we can observe the hydrophobic phenomenon by the rounded droplets of water formed on the surface. Taking a closer look, we can see the contact angle between water mass and the surface is very large, which is the trait of a hydrophobic surface. On the other hand, the hydrophilic surface with a smaller contact angle with water is less common.

Product Performance
ARC-FLASH thin-film coating technique can be applied on smooth surfaces such as glass, mirrors, ceramic tiles, and stones, then provide a super-hydrophilic property to achieve self-cleaning, anti-dust, anti-fogging and heat-dissipating functions.

Experimental proofs of self-cleaning function

(左)The difference of water shapes on both sides is apparent when observed at a horizontal perspective.
(右)“ARC”was written on both sides of the glass with oil-based marker, which is very difficult to remove.

(左)Water was dripped on the unprocessed half of the glass, and nothing happened to the oil ink.
(右)Water was dripped on the processed half, and the “ARC” mark had floated slightly. This was due to the contact angle between water and processed glass is so small that water molecules can even go under the oil ink and shove it up.

Let it stand for 5 seconds, and the “ARC” mark on the right side was shoved up and floating with water while nothing changed on the unprocessed part.

More water was dripped on both sides, and on the processed part with hydrophilic and self-cleaning properties, the ink mark completely faded while nothing changed on the unprocessed half.

Experimental proofs for anti-fogging function

A regular piece of glass with no processing on the left-hand half and with thin-film coating on the right-hand half by spurting steam on both sides of the glass, the processed side showed a much greater anti-fogging effect than the unprocessed side.