Versatile new surface coating can protect the hulls of ships and quickly diagnose cancer, writes HELEN GALLAGHER.
SLICK NEW water-repellent surface coatings developed in Belfast are so versatile they could be used for anything from protecting the hulls of ships to enabling on-the-spot diagnosis of throat and lung cancer from a single breath.
Dr Iain Larmour of the school of chemistry and chemical engineering in Queen’s University Belfast won the Royal Irish Academy Young Irish Chemist of 2008 for his work with these unusual materials. He conducted the research under Dr Steven Bell, director of the innovative molecular materials group.
“We decided to make a coating for metals that repels water. You can think of it as being a bit like the wax on your car to keep water off, but much more extreme,” he explains.
The technology is based on the way lotus leaves repel water in nature, through tiny crevices on their surface causing “roughness”, Larmour says.
“The first step is creating the structure on the surface to repel water. We took a base metal of copper and immersed it into a silver salt solution, and found the silver deposits giving a rough finish.”
It looks like microscopic fern leaves measuring just 10 to 15 microns, he adds. This is about one tenth the diameter of a human hair.
Once the rough surface is deposited, it is “fixed” with another layer. “The second step is to add a thiol layer containing oil molecules which make it water repellent.”
The resulting super hydrophobic surface is an excellent water repellent, and many applications which involve water touching a surface could potentially benefit from this technology. “There is a very long list of potential applications for this technology, and every time I talk to someone it becomes even longer,” he says.
The ability to apply this technology in powdered copper form makes coating surfaces easy, and opens up countless building and engineering applications, he explains. “From the engineering side we can think about coating ships on the base of the hull, and this will increase the speed through the water and prevent bio-fowling from barnacles and seaweed, or it can be used in high-speed racing.”
There are also applications which could be built into new energy solutions.
“You could also use it to increase the efficiency of wave turbines and prevent bio-fowling. We have had samples in the water for a year and they still have a highly reflective, hydrophobic coating and no degradation,” he says.
“It could also be used to protect suspension cables to prevent water corrosion, and we could also use it to protect electronics. It can be used to pack mobile phones with super- hydrophobic foam so if you drop your phone in water there is no damage.”
Another important area being explored is in medical applications. “There are also potential applications in using it for metal heart implants called ‘stents’ to prevent re-growth [of tissue] over the metal once implanted,” he says.
One of the most novel applications is in the diagnosis of cancer. “The patient would breathe into a tube which is set into an ice-bucket, and the vapour would be condensed into a minute amount of liquid, which under a slight vacuum on the hydrophobic surface collects on to a tiny lump. This lump can then be analysed using a technique called ‘Raman spectroscopy’ to identify the salts, proteins and bio-molecules and determine if cancer is present,” he explains.
The same principle could also be used as a technique to look at detecting chemical weapons or diseases such as anthrax in the air.
Bellis is working with Invest Northern Ireland to commercialise these discoveries. He envisages this technology will be available commercially relatively soon.
“We are keen to package this technology in forms which would be most beneficial in real life and would be more specialised and lower cost.
“We have two active patents for this technology and we are working on developing a whole family of patents around the applications,” he adds.
The award is organised by the Royal Irish Academy’s chemical and physical sciences committee and is sponsored by Eli Lilly.