Nano tape, also known as gecko tape, is a synthetic tape consisting of arrays of carbon nanotubes transferred to a flexible polymer tape backing material. These arrays, called synthetic setae, mimic the nanostructures on the toes of a gecko; this is an example of biomimicry. Adhesion is not achieved through chemical adhesives, but rather through van der Waals forces, which are weak electrical forces generated between two atoms or molecules in close proximity. So far, there is little evidence that nanotape can be recycled like plastic bottles, but it is reusable.
Testing of gecko tape
Test results of this “gecko tape” are as follows: A sample was attached to a 15 cm tall, 40 g plastic Spider-Man hand, allowing it to stick to a glass ceiling, as shown. The tape had a contact area of about 0.5 cm2 (50 mm2) with the glass and was able to withstand a load of more than 100 g (3.5 oz). However, the adhesion coefficient was only 0.06, which is low compared to that of a real gecko (8~16).
Meaning of Van der Waals forces
For geckos, the stickiness, or adhesion, is caused by tiny pillars on their feet. Electrical forces between the molecules in these feet and the surface the gecko walks on (so-called van der Waals forces) allow the gecko to stick to almost any surface. Over the past two decades, a lot of research has been done to create a synthetic version of this system – and it seems to have succeeded: you can now buy gecko tape, a double-sided tape that, as its name suggests, uses the same principle as the gecko’s feet.
Characteristics of geckos
Geckos have demonstrated an extraordinary ability to climb smooth vertical surfaces at high speeds. Their feet have both strong adhesion and the ability to quickly fall off or shear adhesion. The shear stress that gecko tape can withstand is almost four times that of a gecko’s feet, so the tape also has the characteristic of being able to fall off quickly without leaving a trace.
Characteristics of Nano Tape
“A gecko can run on a dirt road and then immediately climb up the glass ceiling,” says Andre Geim of the University of Manchester. “But if you try to use Scotch tape on a sidewalk or a sand court, you can’t stick it to anything afterwards. That’s why gecko tape is called self-cleaning tape. Also, tapes use glue, which eventually runs out, so they can’t stick. Gecko tape is the first tape that doesn’t use glue (i.e. is re-stickable). “
