Featured Research

from universities, journals, and other organizations

Spiders Make Best Ever Post-it Notes

Date:
April 26, 2004
Source:
Institute Of Physics
Summary:
Scientists have found that the way spiders stick to ceilings could be the key to making Post-it notes that don't fall off – even when they are wet.

A scanning electron microscope (SEM) micrograph of the foot of the jumping spider E. arcuata. In addition to the tarsal claws, a tuft of hair called a scopula is found at the tip of the foot, which is what the spider uses to attach itself to surfaces. The long hairs which are distributed over the entire foot are sensitive to touch. Magnification 200x.
Credit: Image courtesy Institute Of Physics

Scientists have found that the way spiders stick to ceilings could be the key to making Post-itฎ notes that don't fall off – even when they are wet. A team from Germany and Switzerland have made the first detailed examinations of a jumping spider's 'foot' and have discovered that a molecular force sticks the spider to almost anything. The force is so strong that these spiders could carry over 170 times their own body weight while standing on the ceiling. The research is published today (Monday 19 April 2004) in the Institute of Physics journal Smart Materials and Structures.

This is the first time anyone has measured exactly how spiders stick to surfaces, and how strong the adhesion force is. The team used a scanning electron microscope (SEM) to make images of the foot of a jumping spider, Evarcha arcuata (pictures available – see notes). There is a tuft of hairs on the bottom of the spider's leg, and each individual hair is covered in more hairs. These smaller hairs are called setules, and they are what makes the spider stick.

The paper reveals that the force these spiders use to stick to surfaces is the van der Waals force, which acts between individual molecules that are within a nanometre of each other (a nanometre is about ten thousand times smaller than the width of a human hair). The team used a technique called Atomic Force Microscopy (AFM) to measure this force. The flexible contact tips of the setules are triangular (pictures available – see notes), and they have an amazingly high adhesive force on the underlying surface.

Andrew Martin, from the Institute of Technical Zoology and Bionics in Germany, said, "We found out that when all 600,000 tips are in contact with an underlying surface the spider can produce an adhesive force of 170 times its own weight. That's like Spiderman clinging to the flat surface of a window on a building by his fingertips and toes only, whilst rescuing 170 adults who are hanging on to his back!"

What makes the van der Waals force an interesting form of adhesion is that, unlike many glues, the surrounding environment does not affect it. The only thing that affects it is the distance between the two objects.

"One possible application of our research would be to develop Post-itฎ notes based on the van der Waals force, which would stick even if they got wet or greasy," said Professor Antonia Kesel, head of the research group in Bremen. "You could also imagine astronauts using spacesuits that help them stick to the walls of a spacecraft – just like a spider on the ceiling."

The total van der Waals force on the spider's feet is very strong, but it is the sum of many very small forces on each molecule. The researchers believe the spider lifts its leg so that the setules are lifted successively, not all at once, and it does not need to be very strong to do this. All you would have to do to lift a future kind of Post-itฎ note is peel it off slowly.

The van der Waals force exists because the movement of electrons in atoms and molecules causes them to become dipolar. A dipolar atom or molecule has a "positive-pole" and a "negative-pole". The positive-pole of one atom or molecule will be attracted to the negative-pole of another. This particular electrostatic attraction is called the van der Waals force, and is in some ways similar to the magnetic attraction between north and south poles of magnets.

"We carried out this research to find out how these spiders have evolved to stick to surfaces, and found that it was all down to a microscopic force between molecules. We now hope that this basic research will lead the way to new and innovative technology," said Professor Kesel.


Story Source:

The above story is based on materials provided by Institute Of Physics. Note: Materials may be edited for content and length.


Cite This Page:

Institute Of Physics. "Spiders Make Best Ever Post-it Notes." ScienceDaily. ScienceDaily, 26 April 2004. <www.sciencedaily.com/releases/2004/04/040426054407.htm>.
Institute Of Physics. (2004, April 26). Spiders Make Best Ever Post-it Notes. ScienceDaily. Retrieved July 26, 2014 from www.sciencedaily.com/releases/2004/04/040426054407.htm
Institute Of Physics. "Spiders Make Best Ever Post-it Notes." ScienceDaily. www.sciencedaily.com/releases/2004/04/040426054407.htm (accessed July 26, 2014).

Share This




More Plants & Animals News

Saturday, July 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How to Make Single Serving Smoothies: Howdini Hacks

How to Make Single Serving Smoothies: Howdini Hacks

Howdini (July 24, 2014) — Smoothies are a great way to get in lots of healthy ingredients, plus they taste great! Howdini has a trick for making the perfect single-size smoothie that will save you time on cleanup too! All you need is a blender and a mason jar. Video provided by Howdini
Powered by NewsLook.com
Boy Attacked by Shark in Florida

Boy Attacked by Shark in Florida

Reuters - US Online Video (July 24, 2014) — An 8-year-old boy is bitten in the leg by a shark while vacationing at a Florida beach. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Goma Cheese Brings Whiff of New Hope to DRC

Goma Cheese Brings Whiff of New Hope to DRC

Reuters - Business Video Online (July 24, 2014) — The eastern region of the Democratic Republic of Congo, mainly known for conflict and instability, is an unlikely place for the production of fine cheese. But a farm in the village of Masisi, in North Kivu is slowly transforming perceptions of the area. Known simply as Goma cheese, the Congolese version of Dutch gouda has gained popularity through out the region. Ciara Sutton reports. Video provided by Reuters
Powered by NewsLook.com
Tyrannosaur Pack-Hunting Theory Aided By New Footprints

Tyrannosaur Pack-Hunting Theory Aided By New Footprints

Newsy (July 24, 2014) — A new study claims a set of prehistoric T-Rex footprints supports the theory that the giant predators hunted in packs instead of alone. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins