Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Plant with 'eggbeater' testure inspires waterproof coating

11.11.2011
A floating weed that clogs waterways around the world has at least one redeeming feature: It’s inspired a high-tech waterproof coating intended for boats and submarines.

The Brazilian fern Salvinia molesta has proliferated around the Americas and Australia in part because its surface is dotted with oddly shaped hairs that trap air, reduce friction, and help the plant stay afloat.

In the November 1 issue of the Journal of Colloid and Interface Science, Ohio State University engineers describe how they recreated the texture, which resembles a carpet of tiny eggbeater-shaped fibers. The plastic coating they created in the laboratory is soft and plush, like a microscopic shag carpet.

In nature, air pockets trapped at the base of Salvinia’s hairs reduce friction in the water and help the plant float, while a sticky region at the tips of the eggbeaters clings lightly to the water, providing stability.

It’s the combination of slippery and sticky surfaces that makes the texture so special, said Bharat Bhushan, Ohio Eminent Scholar and the Howard D. Winbigler Professor of mechanical engineering at Ohio State.

“The Salvinia leaf is an amazing hybrid structure. The sides of the hairs are hydrophobic – in nature, they’re covered with wax – which prevents water from touching the leaves and traps air beneath the eggbeater shape at the top. The trapped air gives the plant buoyancy,” he said.

“But the tops of the hairs are hydrophilic. They stick to the water just a tiny bit, which keeps the plant stable on the water surface.”

In tests, the coating performed just as the Salvinia hairs do in nature. The bases of the hairs were slippery, while the tips of the hairs were sticky. Water droplets did not penetrate between the hairs, but instead clung to the tops of the eggbeater structures – even when the coating sample was turned on its side to a 90-degree vertical.

With commercial development, the coating could reduce drag and boost buoyancy and stability on boats and submarines, Bhushan said.

Bhushan and master’s student Jams Hunt compared the stickiness of their plastic coating to the stickiness of the natural Salvinia leaf using an atomic force microscope. The two surfaces performed nearly identically, with the plastic coating generating an adhesive force of 201 nanoNewtons (billionths of a Newton) and the leaf generating 207 nanoNewtons.

That’s a very tiny force compared to familiar adhesives such as transparent tape or even masking tape. But the adhesion is similar to that of another natural surface studied by Bhushan and other researchers: gecko feet.

“I’ve studied the gecko feet, which are sticky, and the lotus leaf, which is slippery,” Bhushan said. “Salvinia combines aspects of both.”

Bhushan develops biomimetic structures – artificial structures created in the lab to mimic structures found in nature. The gecko feet inspired him to investigate a repositionable, “smart” adhesive, and the lotus leaf inspired the notion of glass that repels water and dirt.

He came to study Salvinia through a colleague in the university’s Biological Sciences Greenhouse, who provided samples of the plant for the study.

Salvinia molesta, also known as giant salvinia, is native to Brazil, and is a popular plant for home aquariums and decorative ponds around the world. It needs no dirt, but lives solely in the water – even moving water such as rivers and lakes.

At some point, the hearty plant escaped from people’s homes into the wild. Now it has proliferated into commercial waterways in North America, South America, and Australia, where it has become an invasive species.

While the plant is a nuisance to ships today, it could ultimately provide a benefit if a commercial coating based on its texture became available. Bhushan has no plans to commercialize it himself, though.

“With this study, we’ve gotten deep insight into a very simple concept [how the Salvinia leaf works]. That’s where the fun is,” he said. “Besides, I’ve already moved on to studying shark skin.”

Contact: Bharat Bhushan, (614) 292-0651; Bhushan.2@osu.edu
Written by Pam Frost Gorder, (614) 292-9475; Gorder.1@osu.edu

Bharat Bhushan | EurekAlert!
Further information:
http://www.osu.edu

More articles from Materials Sciences:

nachricht Scientists create a nanomaterial that is both twisted and untwisted at the same time
16.09.2019 | University of Bath

nachricht New metamaterial morphs into new shapes, taking on new properties
12.09.2019 | California Institute of Technology

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Tomorrow´s coolants of choice

Scientists assess the potential of magnetic-cooling materials

Later during this century, around 2060, a paradigm shift in global energy consumption is expected: we will spend more energy for cooling than for heating....

Im Focus: The working of a molecular string phone

Researchers from the Department of Atomically Resolved Dynamics of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg, the University of Potsdam (both in Germany) and the University of Toronto (Canada) have pieced together a detailed time-lapse movie revealing all the major steps during the catalytic cycle of an enzyme. Surprisingly, the communication between the protein units is accomplished via a water-network akin to a string telephone. This communication is aligned with a ‘breathing’ motion, that is the expansion and contraction of the protein.

This time-lapse sequence of structures reveals dynamic motions as a fundamental element in the molecular foundations of biology.

Im Focus: Milestones on the Way to the Nuclear Clock

Two research teams have succeeded simultaneously in measuring the long-sought Thorium nuclear transition, which enables extremely precise nuclear clocks. TU Wien (Vienna) is part of both teams.

If you want to build the most accurate clock in the world, you need something that "ticks" very fast and extremely precise. In an atomic clock, electrons are...

Im Focus: Graphene sets the stage for the next generation of THz astronomy detectors

Researchers from Chalmers University of Technology have demonstrated a detector made from graphene that could revolutionize the sensors used in next-generation space telescopes. The findings were recently published in the scientific journal Nature Astronomy.

Beyond superconductors, there are few materials that can fulfill the requirements needed for making ultra-sensitive and fast terahertz (THz) detectors for...

Im Focus: Physicists from Stuttgart prove the existence of a supersolid state of matte

A supersolid is a state of matter that can be described in simplified terms as being solid and liquid at the same time. In recent years, extensive efforts have been devoted to the detection of this exotic quantum matter. A research team led by Tilman Pfau and Tim Langen at the 5th Institute of Physics of the University of Stuttgart has succeeded in proving experimentally that the long-sought supersolid state of matter exists. The researchers report their results in Nature magazine.

In our everyday lives, we are familiar with matter existing in three different states: solid, liquid, or gas. However, if matter is cooled down to extremely...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Society 5.0: putting humans at the heart of digitalisation

10.09.2019 | Event News

Interspeech 2019 conference: Alexa and Siri in Graz

04.09.2019 | Event News

AI for Laser Technology Conference: optimizing the use of lasers with artificial intelligence

29.08.2019 | Event News

 
Latest News

Too much of a good thing: overactive immune cells trigger inflammation

16.09.2019 | Life Sciences

Scientists create a nanomaterial that is both twisted and untwisted at the same time

16.09.2019 | Materials Sciences

Researchers have identified areas of the retina that change in mild Alzheimer's disease

16.09.2019 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>