What one should know about the difference between the pyrolytic “self-cleaning” glass and any other easy-to-clean or hydrophobic glass:
The pyrolytic Self-cleaning glass consists of a hydrophilic coating with photocatalytic properties fused into the glass at high temperatures during the manufacturing process.
This type of coating typically reacts with the sun’s ultraviolet light and water (rain or induced water spray). Thus, these two elements (sunlight and water) must be present for the coating to be effective, creating a sheeting action so that water can easily rinse the loosened dirt away.
Due to its integral characteristics, there are many limitations to this concept of “self-cleaning”, such as the following:
- glass must receive both sunlight and water
- it is not applicable to all kinds of glass
- cannot be applied in the field but rather at manufacturing level only (making repair or replacement a lot more expensive)
- it’s typically a lot more expensive than hydrophobic coatings.
By contrast, hydrophobic coating requires no ‘activation’ since it chemically reacts during its own process in less than 2 seconds and immediately bonds to the surface. Although othertheories refer to the “self-cleaning” glass as those coatings with contact angles in excess of 105º, where the mechanical action required is virtual unnecessary and no accumulation of contaminants occurs.