Nav: Home

Barnacle busting: ONR-sponsored research targets ship biofouling

October 13, 2016

ARLINGTON, Va.--Individually, tiny barnacles pose little threat to hulking U.S. Navy ships. But when clustered in thick clumps on a vessel's hull--a natural occurrence called biofouling--these sticky crustaceans can slow the ship and increase its fuel consumption by 40 percent.

To deal with this small yet expensive pest, the Office of Naval Research (ONR) is sponsoring work by Dr. Xuanhe Zhao, an associate professor at the Massachusetts Institute of Technology. Zhao and his team have created an adhesive material that can help barnacle-fighting coatings stick to metal hulls better and longer; retain moisture and not dry out; and avoid the use of toxic chemicals and other pollutants.

"Biofouling is a major concern for the Navy, leading to hundreds of millions of dollars a year in fuel and maintenance costs," said Dr. Steve McElvany, a program manager in ONR's Sea Warfare and Weapons Program, who oversees Zhao's research. "It's especially bad when the ship is docked in port. Barnacles like those environments and tend to accumulate rapidly, in large quantities."

Barnacles are adversaries as old as sailing itself. For centuries, mariners fought the critters with everything from tar to wax. Currently, the Navy uses copper-based paints and coatings to kill barnacles or prevent them from latching on to hulls. While effective, these toxic materials leach into the water, negatively impacting aquatic life. The Navy is seeking environmentally friendly coatings that can keep hulls clean and reduce fuel costs.

One solution vital to Zhao's efforts could be hydrogels, which can absorb water and hold it in the form of a gel. These extremely soft, slippery substances can be spread on a ship's underside like sealant to prevent barnacles from sticking to the metal. Barnacles prefer hard, solid spots to attach themselves and don't like surfaces such as hydrogels.

Zhao's research addresses the challenge of keeping hydrogel coatings soft, wet and securely fastened to metal hulls. Using a chemical bonding agent called benzophenone, his team devised a way to fuse hydrogels with elastomers--elastic polymers (like silicone and natural rubber) that are stretchy, durable and impervious to water. The result is a sticky, water-trapping barrier that keeps hydrogels robust enough to potentially withstand the harsh hull conditions of a ship at sea.

"Our approach was inspired by human skin," said Zhao. "The skin has an outer epidermis that protects nerves, capillaries, muscles and organs--and keeps them from drying out, maintaining their compliance. However, we can actually stretch the hydrogel-elastomer hybrid to seven times its original length and the bond still holds. It's that strong and flexible."

The hybrid also has potential as a circuit for transporting ions, which are electrically charged molecules. These natural circuits could be used to detect the presence of barnacles on a hull, said Zhao. Once the crustaceans are identified, a specially designed hydrogel could pump barnacle-repelling enzymes via grooves etched into the elastomer.

In addition to biofouling defense, Zhao believes the hybrid material also might be used as a smart bandage outfitted with electronics and drug reservoirs--allowing it to monitor wounds and vital signs like body temperature, detect bacteria and administer antibiotics, and alert a doctor when more medicine is required.

"Our main focus is helping the Navy deal with the issue of biofouling," said Zhao. "But it's also exciting to think of the other possibilities for this material. This is still very basic research, but we envision numerous potential applications and uses for hydrogels and elastomers."

Zhao is a 2014 winner of ONR's Young Investigator Program, a prestigious grant awarded to scientists and engineers with exceptional promise for producing creative, state-of-the-art research that appears likely to advance naval capabilities.
-end-


Office of Naval Research

Related Hydrogel Articles:

Micron-sized hydrogel cubes show highly efficient delivery of a potent anti-cancer drug
Researchers at the University of Alabama at Birmingham and Texas Tech University Health Sciences Center have developed micro-cubes that can sponge up a hydrophobic anti-cancer drug and deliver it to cancer cells.
3-D-printable implants may ease damaged knees
A cartilage-mimicking material created by researchers at Duke University may allow surgeons to 3-D print knee menisci or other replacement parts that are custom-shaped to each patient's anatomy.
Rabbits' detached retina 'glued' with new hydrogel
A newly developed elastic gel administered in liquid form and shown to turn jellylike within minutes after injection into rabbits' eyes to replace the clear gelatinous fluid inside their eyeballs, may help pave the way for new eye surgery techniques, says an international team of researchers led by Japanese scientists.
Transparent gel-based robots can catch and release live fish
Engineers at MIT have fabricated transparent, gel-based robots that move when water is pumped in and out of them.
Skin cells 'crawl' together to heal wounds treated with unique hydrogel layer
A team led by Professor Milica Radisic in U of T Engineering has demonstrated for the first time that their peptide-hydrogel biomaterial prompts skin cells to 'crawl' toward one another, closing chronic, non-healing wounds often associated with diabetes, such as bed sores and foot ulcers.
New hydrogel can take organoids from dish to clinic
EPFL scientists have developed a gel for growing miniaturized body organs that can be used in clinical diagnostics and drug development.
Controlling bleeding disorders with fitted hydrogel casts
A team of researchers at Harvard's Wyss Institute for Biologically Inspired Engineering, Brigham and Women's Hospital, the Mayo Clinic and MIT provides proof-of-concept and first preclinical evidence in animal models that a shear-controlled hydrogel-based embolic agent can be delivered by catheters and injected into blood vessels to form robust and safe blockages.
Collagen hydrogel scaffold and fibroblast growth factor-2 accelerate periodontal healing of class II
A new regenerative scaffold made of biosafe collagen hydrogel and collagensponge could possess the ability of retaining fibroblastic growth factor-2 (FGF2) and stimulate the periodontal tissue regeneration, according to new research published in The Open Dentistry Journal.
Researchers create stretchy, biocompatible optical fibers
Researchers from MIT and Harvard Medical School have developed a biocompatible and highly stretchable optical fiber made from hydrogel -- an elastic, rubbery material composed mostly of water.
Researchers reduce expensive noble metals for fuel cell reactions
Washington State University researchers have developed a novel nanomaterial that could improve the performance and lower the costs of fuel cells by using fewer precious metals like platinum or palladium.

Related Hydrogel Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#SB2 2019 Science Birthday Minisode: Mary Golda Ross
Our second annual Science Birthday is here, and this year we celebrate the wonderful Mary Golda Ross, born 9 August 1908. She died in 2008 at age 99, but left a lasting mark on the science of rocketry and space exploration as an early woman in engineering, and one of the first Native Americans in engineering. Join Rachelle and Bethany for this very special birthday minisode celebrating Mary and her achievements. Thanks to our Patreons who make this show possible! Read more about Mary G. Ross: Interview with Mary Ross on Lash Publications International, by Laurel Sheppard Meet Mary Golda...