Super-hydrophobic coatings and there impact on anti-friction and corrosion performance.
The techno sounding term ‘hydrophobic nano-coatings’ describes the application of thin films onto various substrates normally for protection against the elements. These thin films may be simple in nature and applied manually (polishing and waxing of automotive paint finishes as an example).
These coatings are usually without structure (flat) acting as a barrier coating to repel water away from the substrate using the relative surface tension properties of the coating verses the water droplets while also providing an aesthetically pleasing shine. There are many other more complex methods of applying thin films for protection of various metallic and polymeric substrates such as ion exchange and spatter techniques.
Our accelerated weathering and environmental testing laboratories have helped provide numerous thin film manufacturers with a means of measuring weathering performance by exposure to simulated sunlight with controlled variations in humidity with or without water spray to provide thermal shock and to mimic rain.
This test method is called xenon arc weathering and is the best laboratory replication of full sunlight spectrum between 290 and 800nm. Geographical location can be taken into account by adjustment of irradiance, temperature and relative humidity levels.
Super-hydrophobic coatings are even better at water repulsion as well as providing excellent anti-friction / non-stick properties. These coatings must have a topographical structure to work well and there impact on corrosion protection is vast due to there ability to repel water and keep oxygen from the air away from the substrate therefore stifling the corrosion reaction equation in metallic materials.
There are many examples in nature of super-hydrophobic surfaces and probably the best known one can be described with the saying ‘water off a ducks back’. The complex ridged structure of feathers help to provide super-hydrophobic properties causing the water to be attracted to itself so it will ‘ball up’ and roll away without a trace.
Take a look at this video (see link below) and let your imagination run wild with the numerous applications in all sectors (industrial, aerospace, automotive, electronic, textile, bio-medical etc…) where super-hydrophobic coatings can protect and enhance the performance of low cost substrates.
https://www.youtube.com/watch?v=SIiv-hkRvZE&list=UUctU7ssWjBx6E3HQ5xV6hDQ