Posted on 08 October 2007

 

Source: Antara, October 5, 2007

Scientists have developed a transparent new plastic as strong as steel and as thin as a sheet of paper, according to a study released Thursday by Science magazine.

Made out of clay and a non-toxic glue similar to that used in school classrooms, the composite plastic is biodegradable and requires very little energy to produce, lead researcher Nicholas Kotov said.

"It`s as green as you can imagine," he said, adding that the material is also quite cheap to produce.

The plastic could be used to reduce the energy required to separate gasses in chemical factories, improve microtechnology such as microchips or biomedical sensors and even one day produce lighter, stronger armor for soldiers or police and their vehicles.

Kotov has already begun developing practical applications for the composite plastic which could become commercialized within a year or two.

"We`re still at the exploratory stage but the machine is now being built in our lab to build piece as big as one meter by one meter," he told AFP in a telephone interview.

Producing a composite material out of nano-sized building blocks that can maintain its strength at such large sizes has long confounded scientists.

Kotov managed to do it by mimicking the brick-and-mortar molecular structure found in seashells.

His engineering team at the University of Michigan build a robot which stacks the nanosheets like bricks in an alternating pattern and uses a glue-like polymer to create cooperative hydrogen bonds between the layers that can easily reform in another place if the bond is broken.

It takes a few hours to build up the 300 layers needed to make a thin sheet of the plastic as the robot`s arm dips in an out of vials of glue and a dispersion of clay nanosheets.

"When you have a brick-and-mortar structure, any cracks are blunted by each interface," Kotov explained. "We`ve demonstrated that one can achieve almost ideal transfer of stress between nanosheets and a polymer matrix."

The study will appear in Friday`s edition of Science. (*)

 

 

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