PITT RESEARCHERS CREATE MOLECULE-SIZED NETWORKS WITH NANOSCALE RODS Advances in Microelectronics, Superstrong Polymers Possible

PITTSBURGH, August 4 -- Adding solid rods measuring just a few billionths of a meter long to polymers can dramatically improve the mechanical, thermal, and electrical properties of the mixture, according to a study by University of Pittsburgh researchers.

The researchers, led by Anna C. Balazs of Pitt's chemical and petroleum engineering department, and David Jasnow, chairman of Pitt's physics and astronomy department, used two-dimensional simulations to examine how the tiny rods interacted in mixtures of two polymers. Other team members included Gongwen Peng, Feng Qiu, and Valeriy V. Ginzburg.

Their findings, published in the June 9 edition of Science, could lead to faster and easier production of electrically-conducting pathways in insulating materials or to the creation of reinforcing structures in organic/inorganic composites.

The researchers found that nanotubes embedded in the polymers that naturally repel one another can align end-to-end, creating possible electrical pathways in the mixture. Rodlike nanoparticles naturally arrange themselves into percolating networks that strengthen the polymer blend to which they are added.

"Manufacturers are already aware that adding larger particles to polymers can increase the strength. Anyone with a reinforced tennis racquet or automobile tires is already taking advantage of this phenomenon. We're showing that it's possible on the nano-scale, as well," said Balazs.

By describing the behavior of the added nanoparticles, their findings should assist other polymer researchers in developing new materials. Most promising, say Balazs and Jasnow, are applications in the automotive industry, where the electrical pathways created by nanotubes could be used to create more efficient batteries, and the strong polymers could be fabricated into lightweight parts for automobile bodies and chassis.

"This work gives experimentalists a lot of hints, cheaply," said Balazs. "It will provide relevant information for industrial chemists, improving their efficiency, and can provide them with a good idea of expected behavior when adding particles to polymeric blends."