If anything good came out of the 2010 Gulf of Mexico oil spill, it was that it got people thinking about technologies for cleaning up future spills. While things like magnetic soap, nanosponges, and autonomous robots are all in the works, a group of scientists recently announced the results of their research into another possibility – oil droplet-gathering microsubmarines.

The magnetically-guided “submarines” are actually based on existing microtube engines, that were developed to transport and deliver medication within the human body. Each of the nanomachines is about eight micrometers long – approximately ten times smaller than the width of a human hair – and has an open, funnel-like front end. They are powered by an inner layer of hydrogen peroxide, which reacts with the surrounding liquid to produce jets of bubbles, which shoot out the back of the engines to rapidly propel them forward.

The group of American and Spanish researchers, led by the University of California - San Diego's Prof. Joseph Wang, applied a superhydrophobic coating to the gold outer surface of these machines. This water-repellant skin lets them to slip through the water easily, while at the same time allowing them to absorb any oil droplets that they encounter.

In laboratory tests, the microsubmarines were turned loose in water samples that were contaminated with olive oil and motor oil. The results were promising, in that the subs were able to collect and transport oil droplets. Needless to say, cleaning up oil spills in the open ocean would be another matter. Scores of the subs would be needed, and the scientists suggest that they might have to be powered by an external source, such as electrical or magnetic fields.

Full details on the research can be seen in a paper that was recently published in the journal ACS Nano.

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