The tangled nature of the polymer filaments, with heat-stopping
voids indicated as dark blobs (left) and the molecules lining up
when drawn and heated into a thin thread (right), compressing
the voids, making the material a good conductor (Image: Gang
Chen) Polyethylene is the most widely used polymer in the world,
most commonly used for packaging and plastic shopping bags. And
like most polymers it is a very good insulators for both heat
and electricity. But now an MIT team has developed a new process
that causes the polymer to remain an electrical insulator but
conduct heat very efficiently in just one direction, unlike
metals, which conduct equally well in all directions. This may
make the new material especially useful for applications where
it is important to draw heat away from an object, such as a
computer processor chip.