IMAGINE rolling up an oil slick like a carpet and carrying it away. A new
water-based gel might just make that possible, say British scientists. And
because the gel is highly porous, its inventors also believe you could use it to
treat burns with antibiotics.
The hydrogel is based on a new water-soluble polymer developed by scientists
at the University of Bradford. Details of the polymer are secret pending a
patent application, but you make the gel by reacting the new polymer with water
and another commercially available polymer. Although the resulting gel is almost
entirely water, it is one thousand times stronger than similar gels, say the
developers.
The hydrogel can also absorb up to half its own weight in oil, for example,
without affecting its own composition. So it should be possible to spray liquid
gel onto oil spills and roll it up after it has thickened. You can even reverse
the reaction afterwards to extract the oil. But the gel won鈥檛 work on choppy
water where mechanical stresses break it up.
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Other techniques involving rolling up oil spills have been developed in the
past, says David Blake, logistics manager with the Oil Spill Response
cooperative in Southampton. But these have not provided for the extraction of
the oil afterwards. Normally, the 鈥渙il roll鈥� would have to be burned. Booms can
be used to contain oil spills before they are pumped out of the water by
machines, says Blake. 鈥淏ut this only works with a current speed of less than one
knot,鈥� he says. The other way is to use chemical dispersants to spread the oil
out over a larger area.
What makes the gel unique, says one of the inventors, Donald Eagland, is the
extremely strong molecular cross links that form between the two polymers
without altering the gel鈥檚 structure, halfway between liquid and solid. The
choice of catalyst, also a secret, strongly influences these highly elastic yet
strong bonds, explains Eagland. Change the catalyst, he says, and you can
precisely control the rate or the strength of the reaction.
Because the gel is so absorbent and the reaction so controllable, doctors
might find it very useful. For example, the gel might deliver antibiotics to
burns victims while forming a protective layer over the wound. And, says
Eagland, 鈥渋t would make an absolutely superb material for breast implants鈥�. This
is because you can make the material as elastic as you want.
Eagland also says the hydrogel would be ideal for making comfortable contact
lenses, since it won鈥檛 dry out and irritate your eyes.
鈥淲e now want to develop the medical applications,鈥� say Eagland. He and
co-inventor Nicholas Crowther have started work on a project to use the gel
as a base for growing skin cells to treat burns. As yet, they have not shown the
gel is bio-compatible but they are confident that it will be.
If people can overcome a slight 鈥測uk鈥� factor, there鈥檚 another application the
Bradford team haven鈥檛 ruled out: a spray-on condom. Eagland says that the gel
could provide 鈥渁 very comfortable and snug fit鈥�.