Microscopic animals inspire novel glass

Washington: Inspired by the microscopic animals called water bears, researchers have created a new type of glass that could improve the efficiency of electronic devices such as LEDs, optical fibres and solar cells.

University of Chicago Professor Juan de Pablo's 20-year exploration of the unusual properties of glass began with the water bears. The creatures, which go by the more formal name of tardigrades, have the ability to withstand extreme environments of hot and cold, and even the vacuum of space. When de Pablo read about what happens when scientists dry out tardigrades, then revive them with water years later, his interest was piqued.

"When you remove the water, they very quickly coat themselves in large amounts of glassy molecules," said de Pablo. "That's how they stay in this state of suspended animation," he said. This led him to the unexpected discovery of a new type of glass, which was described in an earlier study.

The new study bolsters the earlier glass research, which found indications of molecular order in a material thought to be entirely amorphous and random. Their results potentially offer a simple way to improve the efficiency of electronic devices such as light-emitting diodes, optical fibers, and solar cells.

"Randomness is almost the defining feature of glasses," de Pablo said. "What we have done is to demonstrate that one can create glasses where there is some well-defined organisation," de Pablo said. Researchers show how the vapour-deposition process can create new glassy materials by manipulating their molecular orientation.

Using vapour deposition, researchers create glasses in a vacuum chamber by heating a sample material, which vaporises, condenses, and grows atop an experimental surface. In their latest work, the researchers compared three data sets with each other - the simplified computer model of their earlier paper; a new, much more sophisticated computer model; and the experimental results.

The experimental results require some interpretation of the molecular configuration because of inherent limitations of optical measurement techniques. But in the atomic-scale computer simulations, researchers can exactly specify the molecular configuration. "We have been able to generate new glasses with new and unknown properties through this combination of experiment, theory and computation," de Pablo said. The study was published in the Journal of Chemical Physics.