By Emmet Cole
A team of Italian scientists says their latest nanotech discovery is the secret to the wall-scaling Spiderman suit.
Professor Nicola Pugno, an engineer and physicist at Polytechnic of Turin, Italy, has created a hierarchy of adhesive forces he claims are strong enough to suspend a person’s full body weight against a wall or on a ceiling. The adhesive is also easy to detach, according to the paper.
The carbon nanotube-based technology could lead to nano-molecular loops and hooks that would work like microscopic Velcro.
Scientists have been trying to replicate the "Spidey" or "gecko"
phenomenon for years, and experts who reviewed the paper say Spiderman doesn't have any competition just yet. But the paper, published August
29 issue of the Journal of
Physics: Condensed Matter, is an unprecedented step in the right direction.
[In the graphic, Pugno pulls together existing research for a Spidey suit: Spiderman must have large cobwebs and self-cleaning, superadhesive and releasable gloves and boots. Invisible large cables (Pugno 2006b) could be realized with nanotube bundles (related inset from (Zhang et al 2005)), whereas gloves and boots, mimicking spider (related inset from (Desel et al 2004)) or gecko (related inset from (Gao et al suggested by our analysis. Note that the nanotube forest is superhydrophobic (water repellent) and thus self-cleaning (related inset from (Lau et al 2003))]
Pugno's paper claims that a transparent cable with cross-section of .31
square inches can support a man and, with special gloves and boots, could enable the wearer to remain attached to a ceiling. The Italian researchers were not immediately available for comment.
Like the feet of spiders and geckos, the hooks and hairs are self-cleaning and water-resistant, according to the paper, so they won't wear or get clogged by bad weather or dirty surfaces and will withstand extreme environments, including the deep sea.
The basic physics look promising, but some issues need to be resolved, said Ronald S.
Fearing, an electrical engineering professor at the
University of California at Berkeley and an expert in biologically inspired synthetic gecko adhesives.
"We already know that if you take the performance of the gecko and scale it up to a person, you'd be all set," he said. "We don't know all the details of how the gecko works, however."
Pugno admits in the paper that the effect of size on adhesion strength is not completely understood. Also, human muscles are different from a gecko's -- we would suffer considerable muscle fatigue if we tried to stick to a wall for many hours.
Estimating the adhesion between two surfaces is an extremely difficult problem, said Andrew
Fisher, Professor of Physics in the Department of Physics and
Astronomy, University College London (UCL). It's extremely difficult to quantify the effects of imperfections in various surfaces, he said.
"It's embarrassing that at the beginning of twenty-first century science, when we understand so much about exotic quantum mechanics and the cosmology of the early universe, there are still many things we don’t understand about how relatively mundane things stick together,"
Fisher said.
Still, Pugno is the first to pull together many already-established principles of physics behind adhesion into a workable concept, Fisher said. He added that he could envision a prototype suit in three years.
Previous research into the adhesive properties of geckos have not always delivered on their early promise and while a Spidey Suit may sound like the stuff of pipe-dreams, Professor Pugno is better known for debunking hype than creating it. In 2006, he published a paper that generated much discussion in which he demonstrated that a cable made of carbon nanotubes would not be strong enough to serve as a space elevator.
