Hydrophobic glass coatings - Automotive and Marine

Hydrophobic coating a general term used to describe the usage of as substance that assists in clear visibility whilst driving a vehicle, sailing a yacht or larger ship.

Driving through rain poses a double challenge. On top of dealing with slippery roads, you've got to strain to see the road itself. Even the newest windscreen wipers can't always improve visibility and driver comfort.

Some of the advantages of an application to a vehicle windscreen are:

• Greater safety - The secret is a special polymer coating applied across the entire glass surface, forming a durable barrier between the water and the windscreen. That not only prevents smearing, but when you travel above 50 km/h The water actually slides off the glass, creating superior visibility on motorways. The result is greater safety on all counts, including a 33% improvement in
• visibility and a 25% increase in driver response time - The non-stick surface even makes it easier to remove ice, dirt, insects and other objects from blocking your view. Much like Teflon used in cooking utensils although the utensils require cleaning, the food residue comes off easier and generally requires a wipe with a cloth instead of scrubbing with an abrasive sponge.
• Better visibility - Hydrophobic glass increases visibility by 33% compared to untreated glass, under some conditions allowing you to see through a rainstorm with confidence and comfort. Plus the fact that hydrophobic glass improves visibility for the entire glass including areas the wipers cannot reach.
• Improved response time - Drivers looking through hydrophobic glass appear to react to road conditions and hazards 25% faster than drivers behind standard glass. Those precious seconds can make all the difference.
• High speed safety - At speeds above 50 kph, water slides straight off the surface of hydrophobic glass, making it easier to see the road sometimes even with the wipers turned off.
• Increased wiper life - Hydrophobic glass reduces the need for windscreen wipers under normal conditions, slowing wear and tear on the blades.
• Easier to clean - The surface of hydrophobic glass makes it much easier to remove ice, insects, dirt and grime, helping you to keep the windscreen clear in every season.
• Long lasting protection - Unlike aftermarket solutions, hydrophobic glass penetrates the surface of the glass making it very durable, frequency of reapplication will be dependent on the climate. Dry and dusty conditions will create added abrasion and the coating will last less than in a different climate.
• Long lasting - Almost any type of glass can be converted to hydrophobic glass and a simple regeneration kit can restore hydrophobic glass to full strength after a few years of usage.

The protective surface of hydrophobic glass actually changes the shape of water droplets on the windscreen itself. Because the water has less contact with the glass, the droplets become rounder, making it easier for the windscreen wipers or wind to remove them. That prevents smearing and increases visibility even more.

Durability and lifespan

Hydrophobic coatings in the marine industry are not used as extensively as in the automotive industry except in fresh water yachts and small craft. 

Due to the fact that the majority of marine craft are salt water based and therefore after a period of time the windscreen obtains a coating of salt which adds to decreased visibility. This problem is normally solved with water nozzles spraying clean water down the surface, the wipers washing the salt off and then the coating becomes effective again but the effect is not as long-lasting as in the automotive windscreen industry.

Scientific progress is being made within this industry to perfect the application of the coating to improve the durability and lifespan of an application.

Sheeting water

Hydrophilic coatings act positively with water, preventing fogging and providing optical clarity. The coatings reduce distortion by interacting positively with water, causing condensates to spread uniformly over the surface of the coated glass; sheeting water rather than forming droplets that scatter light.

Some companies are currently working on the perfection of water repellant hydrophobic coating as an organic film that will not degrade or delaminate over time, virtually lasting indefinitely. Additionally, these rugged coatings comply with Military Standards. The hydrophobic coating can be provided in either a coated or laminated process. Ideal for touch screens, the coatings provide a barrier against dirt, dust, and a host of aqueous solutions.

Future Developments

Super Hydrophobic Coating: Ways to turn surfaces super hydrophobic with coating.
Recently there is a great interest in the development of super-hydrophobicity on a wide variety of surfaces. Inspired by the “lotus-leaf effect” a lot of techniques have been developed to create super-hydrophobic surfaces. The aim of the scientists is to create a coating with a surface morphology that mimics the morphology of the lotus-leaf. These applications are currently in experimental stage and some of the developed methodologies are coating of substrates with various nanoparticles mixed with polymers
Most of these methodologies have been tested only in lab conditions and not outdoor.

Note: The Lotus Leaf Effect is a micro structured, self-cleaning surface according to nature’s model where dirt is carried off by rainwater.

Lotus Leaf repelling water: