Water Repellent Metal

Scientists at the University of Rochester have developed a laser etching technique that makes metals so water repellent droplets actually bounce off it. The technique uses a high power laser to etch a series of micro scale structures that make the surface highly hydrophobic.

The technique ensure that the hydrophobic effects doe not wear off like teflon or other surface coatings.

There are some very interesting potential defence and aerospace applications, icing free control surfaces for example. The technique is still ‘lab scale’ and takes hours to etch small areas but if it can be scaled there will be many defence manufacturers lining up with their cheque books (the work has been part funded by the USAF up to this point)

Read more here and watch the video below.

 

Would it work on a torpedo skin?

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Engineer Tom
Engineer Tom
February 4, 2015 7:23 pm

How about a ships hull?

The Other Chris
February 4, 2015 7:34 pm

We’d need to know at least two more properties of the surface structures they create:

1) Although the structures repel water, at what coefficient of friction do they do so?

2) What effect on corrosion do the structures have?

monkey
monkey
February 4, 2015 7:47 pm

Very interesting tech , the possibilities seem endless if the surface can maintain its characteristics under polluted conditions, for instance just how fast would s**t fly off a shovel treated with this ;-)

Podzak
Podzak
February 4, 2015 8:24 pm

Isn’t being Hydrophobic against the law?

Hugh
Hugh
February 4, 2015 9:16 pm

Ahh. THAT Rochester.

I was beginning to wonder!

dukeofurl
dukeofurl
February 4, 2015 9:50 pm

The raindrops make a good video but isnt very useful, corrosion protection would be a better angle if the moisture doesnt ‘stick’ as well

John Hartley
John Hartley
February 4, 2015 10:00 pm

Honest guv, I put the carrier in at Portsmouth & it bounced up to Guildford.

Peter
Peter
February 5, 2015 7:05 pm

Ok, so you make etch lines in material and the water bounces off.

What happens when it gets dirty, what effect does this have, and how do you clean it without etching a new pattern. And how long does it take to degrade through dirt outside of a lab.

Interesting, but it would appear a bit impractical. (Though you could probably end up using it for a torpedo if the torpedo was made a bit smaller and contained within a protective container until the point of launch…)

Chris
Chris
February 6, 2015 8:58 am

Peter – I picked up (maybe incorrectly) an inference that as water couldn’t attach itself, neither could water-borne contaminants – hence the idea for minimal flush sewage pipework. It would have been interesting to throw oil-based products at a sample (from petrol to thick oil), alcohol based solvents, a variety of adhesives, fungal spores etc to see if any of those adhered or damaged the water repellent properties. Clearly mechanical damage would destroy micro-grooves.

As for ship hulls, I’d hate to think of the cost of laser-etching every acre of the hull, and that’s putting aside the issue of scaling up the laser’s high-accuracy motion head and making it work over curved surfaces. Perhaps a more practical solution is one the aviation industry was interested in a few years back – it was found that microgrooves disrupted the boundary layer of lamina flow and unstuck it, with significant reduction in drag. The airlines were looking at sticky-back plastic microgroove film that they could wrap around their aircraft (in much the same way as road vehicles now can be given a vinyl wrap). I have no idea if the system was made to work, but you could see that it might be easier to wallpaper the underside of a big grey boat than to zap sub-micron grooves uniformly into the metalwork with a laser.