Washington, August 14 : An Indian-origin Physics professor at Clemson University has devised a way to make tiny carbon springs with shock-absorbing qualities, which may enable small devices like cell phones to bounce rather than crack when dropped.
Apparao Rao and his colleagues from the University of California at San Diego have shown that layers of such tiny springs, called coiled carbon nanotubes, can act as extremely resilient shock absorbers.
The researchers say that the new method is unique because beds of coiled carbon nanotubes can be grown in a single step using a proprietary hydrocarbon-catalyst mixture.
They also envision coiled nanotubes in soldiers' body armour, car bumpers and bushings, and even as cushioning elements in shoe soles.
"The problem we have faced in the past is producing enough of these coiled carbon nanotubes at a reasonable cost to make a difference. Because our current method produces coiled nanotubes quickly in high yield, it can be readily scaled up to industrial levels. After formation, the coiled nanotubes can be peeled off in one piece and placed on other surfaces to form instant cushioning coatings," said Rao.
In a previous study, Rao's team tested more conventional straight carbon nanotubes against coil-shaped nanotubes.
When the researchers dropped a stainless steel ball onto a single nanotube layer, the coiled nanotubes completely recovered from the impact, while the straight ones did not.
"It's like an egg toss. If you move your hand backward as you catch the egg and increase the time of contact over which the impact occurs, the impact will be less forceful and the egg will not break. It is the same phenomenon experienced in catching a baseball," said Rao.
His team has also developed a process that coaxes a traditionally straight carbon nanotube to split into a "Y" shape.
When powered by electrical voltages, the Y-branched nanotubes behave like tiny switches or transistors that process information.
"Our studies with carbon nanotubes have been ongoing for quite some time. Each step along the way has led to the next breakthrough, and each time we've learned more about how they grow and what their applications could be. We believe that carbon nanotubes have tremendous potential for the lives of each one of us," said Rao.