To Bead Or Not To Bead? That Is The Question!

The more we dive into the deep abyss of the detailing and car care industry the more and more we hear the same questions - "How good is the beading effect of the coating?" "How slippery is the surface once coated?" etc etc....
Now there is nothing wrong with these questions however is this really all you want from a coating.... some water beads and a nice feel?
If it was our car the answer would be a resounding no! 
When having a coating applied you should be looking for many benefits including:
  • Easy cleaning
  • No need to polish
  • Resistant to bird fouling
  • Resistant to UV
  • Resistant to harsh acid and alkaline
  • Longevity over time (field testing)
It's these properties that determine the quality of the coating being applied to your vehicle. 
Sure, it looks great when water beads off the surface but over time that effect will reduce and it's at this point the market leading coatings show their true qualities by continuing to protect the paintwork underneath.
Our favourite example to use when explaining the beading isn't everything is a simple household item... a candle. Now here comes the science part so if you've read this far then great effort but now comes the why and the how.... Oh and also this is something you can try yourselves!
Find a candle somewhere and get some water to drop onto the candle. As the water hits the candle the surface energy of the solid candle vs the surface tension of the water causes the water to bead. Due to the high surface tension of water cohesion comes into play when it is put onto a surface with a lower surface energy. Cohesion is attractive forces between molecules of the same type. The water will pull to itself as it has a higher surface energy and therefore form a bead like shape. However, oil in contrast to water has a much lower surface energy and therefore tends to use adhesion (attractive forces between molecules of different types) because the surface energy on the surface is higher than the surface tension of the oil therefore the oil would rather pull to the surface than itself. The same can also be seen with a lotus leaf which is super hydrophobic with water however oleophilic in nature with oil.
So why is this relevant? Well if you have a hydrophobic well beading surface it may still in fact be oleophilic and attracting oils, greases and similar grime and contaminants. These contaminants can be sticky in nature and therefore causing dirt and grime to actually cling on to them as opposed to being repelled like you expect to see from a coating. When it is washed it then makes it harder to remove as oil and water do not mix and in fact separate therefore meaning the water has more to do to wash the contaminants away from the surface. This is why soap works well though as it changes the surface tension of water to hydrophilic and causes the water to sit flat on the surface and allows then for easier cleaning as the water is not using cohesion to bond to itself but is using adhesion to cling to the surface it is touching creating a lubricated layer leading to less chance of scratching during the washing phase. 
So in conclusion, having a coating that beads well is great for the photoshoot, the Instagram feed or Facebook story but just be sure to check the coating has surface energy lower than both oil and water to ensure the easy clean, long lasting effects of the coating are present in what you are applying. Always ask yourself what you want from a coating and ensure whatever you are buying to apply to your vehicle or have applied to your vehicle you are fully aware of what it can and can't do. 
For us we want that easy clean, just polished look after each wash and a fully protected surface from UV and other environmental and atmospheric contaminants whether that's with beads or without! Take a look at our range of ceramic coatings here.

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