Clinging to walls

Many people have been trying to figure out how to duplicate a gecko's ability to cling to a sheet of smooth glass, and a U-M Amherst group claims to have done it. Sort of.

Previous efforts to synthesize the tremendous adhesive power of gecko feet and pads were based on the qualities of microscopic hairs on their toes called setae, but efforts to translate them to larger scales were unsuccessful, in part because the complexity of the entire gecko foot was not taken into account. As Irschick explains, a gecko’s foot has several interacting elements, including tendons, bones and skin, that work together to produce easily reversible adhesion.

...

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.

That "simple everyday materials such as polydimethylsiloxane" struck me as a little odd, but it turns out that it is one of the silicones used as an antifoaming agent and is allowed in a startling array of food products from beer to chewing gum and canned fruit.

I don't know that this is exactly what the gecko does when it clings tightly enough that it could hold 9 pounds up, but if it works as advertised--16 square inches maxes out at load of 700 pounds in a removable/reusable pad--that's not bad at all. For comparison, the adhesive picture hangers are typically rated for about 5 pounds for a surface area that would support 45 with this system.

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  You obviously wouldn't want to trust this kind of support in an earthquake. Wall vibration would probably pull it off. Don't bump into it either.
  
• It is only as strong as the underlying surface. If the paint starts to de-adhere, that TV starts tumbling down.
  
• Will the pad start creeping with time?