Using the world’s lightest material to make electrodes for sensors
Chemists at the TUT study the applications of aerogels, including version of the world’s lightest one.
A small glass tube on the desk in the TUT Laboratory of analytical chemistry contains a cylindrical piece of plastic-like material, which does not seem to have any weight at all. In fact, it is the lightest substance in the world.
Such substances are called ‘aerogels’. “We did not invent this, but we are currently making them,” said Mihkel Koel, Leading Research Scientist at the Chair of Analytical Chemistry. “Finally, we would like to be able to supplement it with molecules that react to light or with other molecules.” Such super-light materials can be used, for instance, in detectors to make extremely light small sensors.
In another type of aerogel, which is only a little heavier, the researchers at the TUT try to use phenols created in the processing of Estonian oil shale. They were once applied in the production of adhesives and resins and similar materials, but this research is no longer continued at the TUT. “We approached it from a slightly different angle and found that they can be used for making very light materials,” said Koel. The current goal is to use this method to transform phenols into insulation materials or metal adsorbents. This is done in cooperation with the Virumaa College of the TUT, which has more know-how related to oil shale. The researchers at the TUT focus on the fundamental scientific aspects, while the Virumaa College investigates the possibilities of application.
Pyrolysis of aerogel, i.e., heating in the absence of oxygen, can produce carbon with a very stable and homogeneous structure. This is of great interest for electrochemists – producing fuel- cells and supercapacitors – which need carbon with a very uniform structure and specific porosity to make electrodes. This research is conducted in cooperation with the electrochemists at the University of Tartu.
The third cooperation project involves colleagues from the same TUT Faculty of Science who are working in the field of synthetic chemistry, particularly with catalysts. “They tell us, which metal is a good catalyst, and we try to attach it to the carbon,” described Koel.
The fourth project is associated with the analyser developed at the same Chair. Aerogels could be used for making electrodes for extra small sensors, resistant to shocks and temperature fluctuations. “We know the general principle and have to find the correct technical solutions,” said Koel.
The study of aerogels at the TUT has resulted in the award of one patent and two doctoral degrees, with a third thesis still in development.