Plastics became ubiquitous during the 20th century. They were hot topics of industrial and academic research, and saw innumerable consumer applications. While plastics can have a wide variety of mechanical properties, they are almost universally good insulators, both of heat and electricity. But a paper out of the Pappalardo Micro and Nano Engineering Laboratories reports on a novel processing technique that aligns the polymer chains of polyethylene, which results in a material that has both a high thermal capacitance and a high electrical resistance.

The researchers forced the polyethylene to form into this aligned morphology by slowly drawing the fiber out of solution using the tip of an atomic force microscope. The new fibrous form of polyethylene conducts heat well along the direction of the fibers—so well, it beats out many pure metals, including iron and platinum.The resulting fiber was about 300 times more thermally conductive than normal polyethylene. This surprising ability to move heat could find uses in any number of technologies that currently rely on metal as a heat transfer medium.

This new method differs from previous attempts at creating a more heat-conductive plastic in that it transforms the morphology of the underlying material instead of using an additive. These prior attempts, while scalable, resulted in only modest gains, since there was high thermal resistance at the interface between the plastic and additive.

It's not currently known how well, if at all, the process will be able to scale up to production. So far, the team has only produced single fibers in the laboratory, but they hope to be able to scale up to macro-scale production of entire sheets of this material.

Nature Nanotechnology, 2010. DOI: 10.1038/NNANO.2010.27 (About DOIs).