Tiny subs built to clear up oil spills

Posted by Emma Woollacott

After the Deepwater Horizon incident in the Gulf of Mexico two years ago, there's been an increasing amount of attention devoted to cleaning up oil spills.

And now an international team of scientists says its successfully tested a revolutionary way of cleaning oil from contaminated waters: getting robots to pick it up and take it away.

The team's self-propelled 'microsubmarines' are similar in principle to those being developed to deliver drugs through the bloodstream. But in order to cope with the rather larger distances involved, it's been neccessary for Joseph Wang and his team at UC San Diego to reduce their fuel consumption and increase their speed.

The devices are propelled by bubbles generated from the oxidation of hydrogen peroxide in their interior.

Wang's team electroplated a bilayer of poly(3,4-ethylenedioxythiophene) (PEDOT) and platinum onto a polycarbonate template. Another bilayer, of nickel and gold (Ni/Au), was then deposited over the first layer by e-beam lithography.

Finally, the submarine was coated with dodecanethiol self-assembled monolayers (SAMs), a 'superhydrophobic' substance that repels water and absorbs oil.

Tests showed that the cone-shaped microsubmarines can collect droplets of olive oil and motor oil in water and cleanly transport them away.

"These results demonstrate the potential of the superhydrophobic-modified microsubmarines for facile, rapid and highly efficient collection of oils in oil-contaminated water samples," say the researchers.