New coating prevents mist and frost on windscreens
A team from Massachusetts Institute of Technology has created a coating which prevents glass surfaces fogging up or frosting when the temperature drops.
The American scientists have created a zwitter-wettable surface which can rapidly absorb moisture from the environment and also counter intuitively repel rain. The coating works by making the water molecules disappear so rapidly that condensation is prevented and cold weather freezing becomes a thing of the past.
The German word ‘zwitter’ means hybrid, it is also a term used by chemists for a product or substance that contains two unique opposite properties at the same time. This exciting new coating is both hydrophobic (to drops of water) and hydrophilic (to gas-phase water molecules).
The high optical quality surface has been created using alternate layering of polymers – PVA (Poly Vinyl Alcohol) and PAA (Poly Acrylic Acid). The additional step of functionalizing the nano blended PVA/PAA with PEG (Poly Ethylene Glycol Mythyl Ether) segments produced a noticeably superior resistance to fogging and frosting. The non-freezing water capacity of the multi-layer film was increased by the PEG segments. The unique properties of the film are achieved by the nanoscale control process, which allows the well known polymers to come together in a new and completely different way.
As well as removing this bane of motorists’ lives the new coating has potential for reading glasses, camera lenses and any glass that could attract mist or steam.