Glass with self-cleaning properties
In the case of glass with self-cleaning properties , the surface behavior is changed compared to normal glass in such a way that dirt can hardly stick to the surface and is largely washed off by running water when it rains. This delays soiling and makes cleaning easier.
Glass with self-cleaning properties is often referred to or equated with the so-called lotus effect and / or associated with nanotechnology . One then speaks of a nano-coating. Glass with self-cleaning properties is called self-cleaning glass in window and facade construction. This creates the impression that the glass no longer needs to be cleaned.
There are three methods to produce a glass with self-cleaning properties:
- Float glass pyrolytically coated with titanium (IV) oxide Surface behavior
: hydrophilic - Nanomaterial combines with the glass
- with a nano-coating
surface behavior : hydrophobic
Float glass pyrolytically coated with titanium oxide
Float glass (flat glass) pyrolytically coated with titanium oxide is dual-active and combines two properties in order to enable the self-cleaning properties. The coating of the outside with titanium dioxide increases the surface energy (hydrophilic) and prevents droplet formation. The water spreads as a thin film of water on the surface to absorb the dirt as it flows off. The self-cleaning properties are enhanced by a photocatalytic effect. The UV absorption of the titanium dioxide coating generates active oxygen . In the process, organic dirt decomposes and the adhesion of the dirt to the surface is reduced.
The coating is applied during glass production.
This process is used by large glass manufacturers such as Pilkington and Saint-Gobain Glass Deutschland GmbH.
Typical glass material (silicon) that chemically bonds with the glass
A glass surface with hydrophobic (water-repellent) and dirt-repellent properties is modified with material typical of glass in order to achieve the self-cleaning properties. During processing, silicon particles combine chemically with the glass surface without changing the other material properties. The refined surface reduces the contact area, so that dirt cannot settle and rainwater forms into drops and when it runs off it absorbs and removes most of the dirt. The self-cleaning properties achieved in this way reduce the cleaning effort and lastingly protect the glass surface against aging, aggressive environmental influences and harmful deposits, among other things.
Glass surfaces modified with nanocoatings
Glass surfaces modified with a nano-coating are equipped with hydrophobic (water-repellent) and dirt-repellent properties in order to achieve the self-cleaning properties. For this purpose, a new surface layer is applied to an existing, usually a smooth, non-hydrophobic surface.
A nano-coating consists of at least two layers: The first layer is for the connection between the existing surface and the new, nano- or macro-structured layer. Nanocoatings enter into a physical connection with an existing surface, such as the z. B. is the case with wallpaper .
A large number of manufacturers offer nano-coatings for use on glass and many other surfaces.
Nano-coatings are applied afterwards.