Contact angles of different surfaces

Ultra-Ever Dry

I was recently offered a place at the Molecular Scale Engineering Centre for Doctoral Training based between Sheffield and Leeds universities, which I was more than happy to accept. Given that I will have a choice about what I’ll be doing, it got me thinking about the types of chemistry done at the centre and the applications that they have in real life. The popularity of surface modification chemistry is growing – I’m even doing some for my fourth year project – and it seems as though this area has almost limitless potential. For example, have a look at this video…

 

 

How awesome is that?! The secret to this kind of technology is to change the properties of the surface to make it hydrophobic (hydro = water, phobic = fear, i.e. hydrophobic things repel water). The Ultra-Ever Dry website claims that the hydrophobic surface creates a barrier of air to stop itself from getting wet… but what does this mean?

The hydrophobicity of a surface (how hydrophobic it is) can be calculated using the contact angle it makes with a droplet of water. The contact angle is the angle between a surface and a fluid at their interface, illustrated below. Ultra-Ever Dry say that surfaces coated with their material have a contact angle of around 170 degrees, making them ultrahydrophobic. This is pretty impressive considering that a contact angle of 180 degrees would make the surface perfectly non-wetting.

Contact angles of different surfaces
Hydrophilic (water loving) surfaces have much lower contact angles than hydrophobic ones. Ultrahydrophobic surfaces have contact angles bigger than 150 degrees.

But not only do Ever Dry coated things repel water, they also repel fats and oils (making it oleophobic). If you’ve ever tried to mix water and oil, you’ll know they don’t mix, and this is because they have completely different properties – so how can this material repel both? I’ve contacted the company to see if they will reveal any more information about how it works, but it’s not likely that they will share very much.

My guess is that the molecules deposited onto the material interact so strongly with oxygen in the air that anything else that tries to reach the surface can’t get past the oxygen molecules. I’ve done my best to explain that using a crudely drawn diagram here…

The way I think Ever Dry works
My best guess on how I think Ever Dry might work based on my knowledge of chemistry now and what is said on the product’s official website

If representatives from the company ever get back to me to reveal their trade secrets, I will let you know! To find out more about me, my research and to read my other posts, you can follow this link to my personal blog: http://danthechemist.wordpress.com/

Dan Jenkinson

Final year chemistry student at the University of Sheffield, wanting to share my love for science with the world.

3 thoughts to “Ultra-Ever Dry”

Leave a Reply

Your email address will not be published. Required fields are marked *