What is Photo-induced Superhydrophiliciy?
SELF CLEANING GLASS
Doping with nanoparticle photocatalyst made the
glass hydrophilic and photocatalyst oxidation decompose the contaminants so the glass always
stay clean.
The coated surface does not repel water at all, so water cannot exist in the shape of a drop, but spreads flatly on the surface of the substrate. And the water took the form of a highly uniform thin film, which behaves optically like a clear sheet of glass. TPX sol: Super Hydrophilicity video demo
When titanium oxide is exposed to light, its surface exhibits superhydrophilicity, with water contact angles of 5 ° or less. Although the underlying mechanism is again the formation of electron-hole pairs under light irradiation, the superhydrophilicity is directly the result of the formation of oxygen vacancies by the interaction of holes with oxygen atoms in the crystalline lattice. Such defects form a hydrophilic domain, and since water is easily adsorbed there, general superhydrophilicity results.
Figure 1 Organic Decomposition
Photocatalyst decomposition capabilities of the treated surface weaken the adhesiveness of matter that contains oils. Rainwater spreads uniformly over the surface and floats away grime, for self-cleaning functionality
Figure 2 Creation of Hydrophilicity
These superhydrophilic properties give rise to an antifogging effect. In addition, when surfaces coated with a titanium oxide photocatalyst are exposed to contaminants such as oil, the combination of superhydrophilicity and oxidative decomposition leads to the contamination being washed away by rain water.
Hydrophobic
A regular glass surface, after it is cleaned or coated with hydrophobic solution, exhibits hydrophobicity, meaning that the contact angle is high. Dirt, water and other residue cling to the glass readily. As water beads up, spots occur – making the glass harder and harder to clean.
Hydrophilic
The hydrophilic glass has a low contact angle, which means that it is smoother than ordinary glass and more resistant to spotting.
When water comes in contact with the photocatalyst surface, it spreads out across the glass. It evaporates more quickly, which translates into fewer water spots on your windows. Your windows will stay cleaner and brighter for a longer time than ever before.
