Study of gecko feet leads to advances in the science of friction (w/Video)

June 4, 2009

(PhysOrg.com) -- Whether it’s driving on icy roads, rock climbing, or getting a better grip on a bat, the science of friction and adhesion plays a role—large and small—in many human activities. In a new research paper published in the Royal Society journal Interface, biology professor Kellar Autumn shows how the nano-hairs on gecko toes can reveal new insights into the fundamental nature of friction and adhesion.

Leonardo da Vinci did the first experiments on friction, and found that most objects slip more easily as they slide faster, which makes intuitive sense. If a person’s foot slips, they are likely to fall. However, Autumn and colleagues studied the nano-hairs on gecko feet and discovered that gecko hairs actually become stickier as they slide faster, and did not wear out even after sliding 300 meters.

Autumn and his research team developed a mathematical theory based on the random vibration of the gecko’s nano-tips. Their theory suggested that it should be possible to fabricate a synthetic gecko-like material that also becomes stickier as it slides.

The video will load shortly
In this video Autumn demonstrates the effects of time and velocity on the capacity of matter to adhere and re-adhere.

Science “first” will advance technology for host of products

In the research, funded in part by the National Science Foundation, team member Mark Cutkosky at Stanford University molded synthetic hairs 10 times larger than real gecko’s hairs. The synthetic hairs became stickier as they slid, and resisted wear-a first for science. This “dynamic adhesive” has many applications, including anti-skid car tires, shoes, and sports equipment.

An interesting side-note to this study is that it provides some of the first empirical support for theories about atomic friction and earthquakes. Autumn and his coauthors suggest that , atoms, and earthquakes may share common dynamics.

“By studying why geckos have the ability to stick to surfaces, the team led by Professor Autumn has made fundamental discoveries about the nature of and adhesion,” said John Rundle, professor of physics and geology, and an expert in earthquake simulation at the University of California-Davis. “These results may lead to advanced synthetic materials with novel and important properties, as well as providing far-reaching new insights into phenomena as disparate as earthquake faults and neural networks, both of which possess similar dynamics.”

More secrets to unearth in nature’s bio-diverse geckos

With over 1,000 species of geckos, each has a unique-pattern of nano-hairs on its toes. Autumn is currently working to understand why geckos have evolved so many different designs, and how this biodiversity can be used to solve sticky engineering problems ranging from automotive assembly to micro-electrical connections.

“One big question is how the size of the hairs affects their function,” Autumn said. “Theory suggests that smaller hairs stick better, but larger structures are easier to fabricate. Fortunately, species of gecko have evolved hairs of different sizes, so it is a matter of measuring hairs from these species.”

Autumn is also working to resolve conflicting studies about the role humidity plays in and studying how rough surfaces and hairs interact.

Provided by Lewis & Clark

Explore further: Duct tape that never loses its stick

Related Stories

Duct tape that never loses its stick

January 7, 2005

Gecko feet hold key to development of self-cleaning adhesives Duct tape that never loses its stick. Bandages that come off without sticky residue or an "ouch." Gecko feet may hold the key to the development of synthetic ...

Engineers create gecko-inspired, high-friction micro-fibers

August 22, 2006

Inspired by the remarkable hairs that allow geckos to hang single-toed from sheer walls and scamper along ceilings, a team of researchers led by engineers at the University of California, Berkeley, has created an array of ...

UA synthetic gecko foot-hairs leading to reusable adhesives

August 15, 2005

The interest of University of Akron polymer researchers in the fascinating ability of geckos to climb any surface and hang from just one toe soon could lead to advances in adhesives used in microelectronics and space applications. ...

Engineers create new adhesive that mimics gecko toe hairs

January 29, 2008

A new anti-sliding adhesive developed by engineers at the University of California, Berkeley, may be the closest man-made material yet to mimic the remarkable gecko toe hairs that allow the tiny lizard to scamper along vertical ...

Nanotube adhesive sticks better than a gecko's foot

June 19, 2007

Mimicking the agile gecko, with its uncanny ability to run up walls and across ceilings, has long been a goal of materials scientists. Researchers at Rensselaer Polytechnic Institute and the University of Akron have taken ...

Recommended for you

Particles self-assemble into Archimedean tilings

December 8, 2016

(Phys.org)—For the first time, researchers have simulated particles that can spontaneously self-assemble into networks that form geometrical arrangements called Archimedean tilings. The key to realizing these structures ...

Nano-calligraphy on graphene

December 8, 2016

Scientists at The University of Manchester and Karlsruhe Institute of Technology have demonstrated a method to chemically modify small regions of graphene with high precision, leading to extreme miniaturisation of chemical ...

ANU invention to inspire new night-vision specs

December 7, 2016

Scientists at The Australian National University (ANU) have designed a nano crystal around 500 times smaller than a human hair that turns darkness into visible light and can be used to create light-weight night-vision glasses.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.