Z-Man or do I mean SpiderMan? They used to make reference to SpiderMan and/or geckos when there was some research breakthrough or other concerning adhesion (specifically, bioadhesion) but these days, it’s all geckos, all the time.
I’m going to start with the first announcement from the research team at the University of Massachusetts at Amherst, from the Feb. 17, 2012 news item on Nanowerk,
For years, biologists have been amazed by the power of gecko feet, which let these 5-ounce lizards produce an adhesive force roughly equivalent to carrying nine pounds up a wall without slipping. Now, a team of polymer scientists and a biologist at the University of Massachusetts Amherst have discovered exactly how the gecko does it, leading them to invent “Geckskin,” a device that can hold 700 pounds on a smooth wall. Doctoral candidate Michael Bartlett in Alfred Crosby’s polymer science and engineering lab at UMass Amherst is the lead author of their article describing the discovery in the current online issue of Advanced Materials (“Looking Beyond Fibrillar Features to Scale Gecko-Like Adhesion”). The group includes biologist Duncan Irschick, a functional morphologist who has studied the gecko’s climbing and clinging abilities for over 20 years. Geckos are equally at home on vertical, slanted, even backward-tilting surfaces.
Here’s a picture illustrating the material’s strength,
This image is meant as an illustration of what the product could do and not as a demonstration, i.e., the tv is not being held up by ‘geckskin’.
There are other research teams around the world working on ways to imitate the properties of gecko feet or bioadhesion (my Nov. 2, 2011 posting mentions some work on robots with ‘gecko feet’ at Simon Fraser University [Canada] and my March 19, 2012 posting mentions in passing some work being done at the University of Waterloo [Canada] are two recent examples).
The University of Massachusetts team’s innovation (from the Feb. 17, 2012 news item),
The key innovation by Bartlett and colleagues was to create an integrated adhesive with a soft pad woven into a stiff fabric, which allows the pad to “drape” over a surface to maximize contact. Further, as in natural gecko feet, the skin is woven into a synthetic “tendon,” yielding a design that plays a key role in maintaining stiffness and rotational freedom, the researchers explain.
Importantly, the Geckskin’s adhesive pad uses simple everyday materials such as polydimethylsiloxane (PDMS), which holds promise for developing an inexpensive, strong and durable dry adhesive.
The UMass Amherst researchers are continuing to improve their Geckskin design by drawing on lessons from the evolution of gecko feet, which show remarkable variation in anatomy. “Our design for Geckskin shows the true integrative power of evolution for inspiring synthetic design that can ultimately aid humans in many ways,” says Irschick.
The research at the University of Massachusetts is being funded, in part, by DARPA (US Defense Advanced Research Projects Agency) through its Z-man program. From the March 2, 2012 news item on Nanowerk,
“Geckskin” is one output of the Z-Man program. It is a synthetically-fabricated reversible adhesive inspired by the gecko’s ability to climb surfaces of various materials and roughness, including smooth surfaces like glass. Performers on Z-Man designed adhesive pads to mimic the gecko foot over multiple length scales, from the macroscopic foot tendons to the microscopic setae and spatulae, to maximize reversible van der Waals interactions with the surface.
Here’s the reasoning for the Z-Man program, from the March 2, 2012 news item,
The Defense Advanced Research Projects Agency (DARPA)’s “Z-Man program” aims to develop biologically inspired climbing aids to enable soldiers to scale vertical walls constructed from typical building materials, while carrying a full combat load, and without the use of ropes or ladders.
Soldiers operate in all manner of environments, including tight urban terrain. Their safety and effectiveness demand maximum flexibility for maneuvering and responding to circumstances. To overcome obstacles and secure entrance and egress routes, soldiers frequently rely on ropes, ladders and related climbing tools. Such climbing tools cost valuable time to use, have limited application and add to the load warfighters are forced to carry during missions.
The Z-Man program provides more information, as well as, images here, where you will find this image, which is not as pretty as the one with the tv screen but this one is a demonstration,
In the very latest news, the University of Massachusetts team has won international funding for its (and Cambridge University’s) work on bioadhesion. From the University of Massachusetts at Amherst March 28, 2012 [news release],
Duncan Irschick, Biology, and Al Crosby, Polymer Science and Engineering, with Walter Federle of Cambridge University, have been awarded a three-year, $900,000 grant from the Human Frontiers Science Program (HFSP) in Strasbourg, France, to study bioadhesion in geckos and insects.
Theirs was one of only 25 teams from among approximately 800 to apply worldwide. HFSP is a global organization that funds research at the frontiers of the life sciences.
Crosby, Irschick and colleagues received international scientific and media attention over the past several weeks for their discovery reported in the journal Advanced Materials, of how gecko feet and skin produce an adhesive force roughly equivalent to the 5-ounce animal carrying nine pounds up a wall without slipping. This led them to invent “Geckskin,” a device that can hold 700 pounds on a smooth wall. Irschick, a functional morphologist who has studied the gecko’s climbing and clinging abilities for over 20 years, says the lizards are equally at home on vertical, slanted and even backward-tilting surfaces.
Not having heard of the Human Science Frontier Program (HSFP) previously, I was moved to investigate further. From the About Us page,
The Human Frontier Science Program is a program of funding for frontier research in the life sciences. It is implemented by the International Human Frontier Science Program Organization (HFSPO) with its office in Strasbourg.
The members of the HFSPO, the so-called Management Supporting Parties (MSPs) are the contributing countries and the European Union, which contributes on behalf of the non-G7 EU members.
The current MSPs are Australia, Canada, France, Germany, India, Italy, Japan, Republic of Korea, Norway, New Zealand, Switzerland the United Kingdom, the United States of America and the European Union.
I wonder how much impact all the publicity had on the funding decision. In any event, it’s good to find out about a new funding program and I wish anyone who applies the best of luck!