Novel materials shake ship scum

Jan 31, 2013
This is an artist's illustration of a surface repelling biofilms. Credit: Phanindhar Shivapooja and Qiming Wang

Just as horses shake off pesky flies by twitching their skin, ships may soon be able to shed the unwanted accumulation of bacteria and other marine growth with the flick of a switch.

Duke University engineers have developed a material that can be applied like paint to the hull of a ship and will literally be able to dislodge bacteria, keeping it from accumulating on the ship's surface. This buildup on ships increases drag and reduces the of the vessel, as well as blocking or clogging undersea sensors.

The material works by physically moving at the , knocking the bacteria away. This avoids the use of bacteria-killing paints, which can contain or other that might accumulate in the environment and unintentionally harm fish or other .

The Duke researchers also say that similar types of materials could be used in other settings where the buildup of bacteria – known as biofilms—presents problems, such as on the surfaces of artificial joint implants or water purification membranes.

"We have developed a material that 'wrinkles,' or changes it surface in response to a stimulus, such as stretching or pressure or electricity," said Duke engineer Xuanhe Zhao, assistant professor in Duke's Pratt School of Engineering. "This deformation can effectively detach biofilms and other organisms that have accumulated on the surface."

The results of the Duke studies were published online in the journal .

Zhao has already demonstrated the ability of electric current to deform, or change, the surface of polymers.

"Nature has offered many solutions to deal with this buildup of that we as engineers can try to recreate," said Gabriel López, professor of biomedical engineering and mechanical engineering and materials science. He also serves as director of Research Triangle Materials Research Science and Engineering Center (MRSEC), which is funded by the National Science Foundation.

"For example, the hair-like structures known as cilia can move foreign particles from the lungs and respiratory tract," Lopez said. "In the same manner, these types of structures are used by mollusks and corals to keep their surfaces clean. To date, however, it is been difficult to reproduce the cilia, but controlling the surface of a material could achieve the same result."

The researchers tested their approach in the laboratory with simulated seawater, as well as on barnacles. These experiments were conducted in collaboration with Daniel Rittschof the Duke University Marine Lab in Beaufort, N.C.

Keeping bacteria from attaching to ship hulls or other submerged objects can prevent a larger cascade of events that can reduce performance or efficiency. Once they have taken up residence on a surface, bacteria often attract larger organisms, such as seaweed and larva of other marine organisms, such as worms, bivalves, barnacles or mussels.

"It is known that bacterial films can recruit other organisms, so stopping the accumulation process from the beginning in the first place would make a lot of sense," Lopez said.

Explore further: Repeated self-healing now possible in composite materials

Related Stories

Hey, bacteria, get off of my boat!

Oct 31, 2011

Submerge it and they will come. Opportunistic seaweed, barnacles, and bacterial films can quickly befoul almost any underwater surface, but researchers are now using advances in nanotechnology and materials science to design ...

Restraint improves dielectric performance, lifespan

Oct 25, 2011

Just as a corset improves the appearance of its wearer by keeping everything tightly together, rigidly constraining insulating materials in electrical components can increase their energy density and decrease their rates ...

MIT crafts bacteria-resistant films

May 15, 2008

Having found that whether bacteria stick to surfaces depends partly on how stiff those surfaces are, MIT engineers have created ultrathin films made of polymers that could be applied to medical devices and other surfaces ...

Recommended for you

Metals go from strength to strength

22 hours ago

To the human hand, metal feels hard, but at the nanoscale it is surprisingly malleable. Push a lump of metal with brute force through a right-angle mould or die, and while it might look much the same to the ...

Chemists achieve molecular first

23 hours ago

(Phys.org) —Chemists from Trinity College Dublin have achieved a long-pursued molecular first by interlocking three molecules through a single point. Developing interlocked molecules is one of the greatest ...

User comments : 0

More news stories

Chemists achieve molecular first

(Phys.org) —Chemists from Trinity College Dublin have achieved a long-pursued molecular first by interlocking three molecules through a single point. Developing interlocked molecules is one of the greatest ...

Metals go from strength to strength

To the human hand, metal feels hard, but at the nanoscale it is surprisingly malleable. Push a lump of metal with brute force through a right-angle mould or die, and while it might look much the same to the ...

ESO image: A study in scarlet

This new image from ESO's La Silla Observatory in Chile reveals a cloud of hydrogen called Gum 41. In the middle of this little-known nebula, brilliant hot young stars are giving off energetic radiation that ...

Patent talk: Google sharpens contact lens vision

(Phys.org) —A report from Patent Bolt brings us one step closer to what Google may have in mind in developing smart contact lenses. According to the discussion Google is interested in the concept of contact ...

Warm US West, cold East: A 4,000-year pattern

Last winter's curvy jet stream pattern brought mild temperatures to western North America and harsh cold to the East. A University of Utah-led study shows that pattern became more pronounced 4,000 years ago, ...