BAE Systems: New Super Adhesive Inspired by Gecko's Sticking Power

Link: BAE Systems: New Super Adhesive Inspired by Gecko's Sticking Power.

A team led by Jeff Sargent and Sajad Haq of BAE Sytems' Advanced Technology Centre has developed "Synthetic Gecko", a surface that grips without glue or pressure.  The surface is made of "layers comprising thousands of microscopic polyimide stalks with splayed tips, closely resembling the mushroom headed hairs on a gecko’s feet."  A square metre can support the weight of a family car.  Possible uses include repair patches or other applications where surfaces need to be attached without fasteners.

Geckos can climb vertical walls and windows using molecular attraction based on van der Waals forces.  More information can be found at How Geckos Stick—New Find May Lead to New Glue.

Commentary:

The article mentions that research is underway to study how adhesion is affected by surface roughness and water.  The gecko foot not only adheres to a broad range of surface, but can repeatedly lift and reattach.  Previous attempts at mimicing the gecko foot suffered from deterioration or contamination of the fine fibres, resulting in reduced effectiveness over time. 

Thanks to Eileen Stephes for the pointer.  Some neat pictures are posted on the Transmaterial site.

2006/12/06 Response to Sam's comment:

The 'trick' is developing strong adhesion that is controllable.  The adhesion in not chemical, but uses something called van der Waals forces between molecules.  There is a discussion on Wikipedia - it states "Geckos toes are extremely double jointed, allowing them to overcome the van der Waals force by peeling their toes off surfaces from the tips inward. In essence, this peeling action alters the angle of incidence between millions of individual setae and the surface, reducing the van der Waals force."  Also, check out UA synthetic gecko foot-hairs leading to reusable adhesives. 

The neat thing is that the gecko is able to maintain the adhesive strength of its footpads over the life of the organism.  Artificial 'gecko tape' had tendencies to fail because of dirt building or clumping of the fine fibres.

Comments

[Sam Burrows]

Surely when stands of polymer are stuck to the wall when you peel the strands away they would break wouldn't they if the grip of these things is enough to hold up a car?

Sam Burrows