Liquid crystals can be radical

What’s she building in there?

the Fulcrum
Published: Oct 5

The problem

HEY, SCIENCE! WHY haven’t you built me an iPod the size of a single cell yet? I’m waiting.
Currently electronics are built out of bulk materials and have inherent size limitations: A wire can only be carved so small if it’s made from an everyday chunk of copper. But imagine if electronic components could be made from large molecules or organics instead of bulky metals.
One day, organic components might be smaller, cheaper, and even easier to fabricate than traditional wires. Sure, it sounds like a great idea, but is it possible?

The researcher

Alicea Leitch doesn’t know either, but she’s trying to find out. Leitch is a post-doctoral researcher in the chemistry department at the University of Ottawa who likes to work on projects that have concrete applications.
Before she arrived at the University of Ottawa, Leitch had already started working on highly reactive chemical substances called radicals.

The project

Radicals can be extremely reactive because they have an unpaired electron, which is just dying to find its soulmate. It’s not exactly picky—radicals will react with just about anything. However, when they are stabilized, the unpaired electron can become very valuable. Sometimes radicals can help carry charges, making otherwise non-conductive materials more interesting.
This makes radicals tempting for molecular electronics. Unfortunately, chemical stabilization almost always vetoes the properties of interest.

The key

To control the radicals without loosing the conductivity, Leitch doesn’t bother with chemical stabilization. Instead, she attaches the radicals to microscopic discs so the previously troublesome unpaired electron doesn’t belong to a single atom. It becomes shared between all the atoms that make up the disc, making it less reactive but still conductive.
On top of that, using discs has unexpected bonuses: They float in liquid and they like to stack in an orderly fashion, like a crystal. This makes them a liquid crystal. If Leitch can get the liquid crystals just right, the discs will automatically assemble into tiny chains.
This natural stacking is great because the structure of molecular electronic components plays a really important role, but is usually hard to control. Because they are stacked together, the single electron can jump from plate to plate, and eventually make its way from one end of the chain to the other.
Together, the conductivity of the unpaired electron and the discs’ self-assembly into long, flexible chains could make Leitch’s liquid crystals into pretty radical wires.