"There are no reliable nontoxic alternatives on the market yet," said Liedert, who invented the material while working on his PhD.
Liedert focused on barnacles, which produce a cement-like protein to glue themselves to both sea-faring fleets and fauna.
Barnacles make up the majority of this kind of "bio-fouling," and are responsible for corrosion as well as weighing down ships, which decreases speed, maneuverability and fuel efficiency.
Like many ocean-dwelling creatures, sharks have a defense against barnacles.
Millions of microscopic teeth-like scales imbedded in a flexible layer of their skin create an uncomfortable and unstable surface for the barnacle and its gluey secretions.
"It's like walking on a stony beach with bare feet," said Liedert. The barnacle larvae can't stick or if they try, they soon let go.
Liedert imitated nature's success by combining the uncomfortable and unstable aspects of shark skin into a surface lined with microscopic ridges made from elastic silicone.
In field tests he conducted on immersed panels, Liedert found that wobbly, parallel ridges spaced between 2 micrometers and 2 millimeters apart inhibited barnacle growth up to 67 percent.
According to Liedert, the barnacle glue sits on top of the micro-peaks instead oozing into the valleys.
In theory, even if tiny larvae can cling for a while, the combination of an unstable surface and the natural drag from a ship's motion should peel them off as they grow larger.
Although Liedert's nontoxic solution seems to works for barnacles, other marine organisms, including mussels, algae and bacterial films that increase the drag resistance of ships must be addressed.
At the Office of Naval Research in Arlington, Va., research to prevent biofouling is focused on biomimetics as well as chemistry and smart coatings.
"The ultimate solution is going to have to be a combination of things — maybe of topographies combined with some specific surface chemistry," said Stephen McElvany, an ONR scientific program officer who manages environmental research projects to develop nontoxic coatings for hulls.
But the success of a coating to prohibit one organism holds the promise for coatings that can stave off many, he said.
Liedert is currently collecting more conclusive evidence for his solution. In a few months, he'll begin analyzing data from small patches of artificial skin he's applied to moving ships.
