A Glimpse Of Silica In Motion | Chemical & Engineering News
Volume 91 Issue 41 | p. 29 | Concentrates
Issue Date: October 14, 2013

A Glimpse Of Silica In Motion

Researchers image atomic dance in two-dimensional glass
Department: Science & Technology
News Channels: Analytical SCENE, Materials SCENE
Keywords: silica, glass, transmission electron microscopy
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False-colored TEM image shows solid (yellow) and molten (blue) silica glass, with actively rearranging atoms in between (red). Each ring of atoms is about 1 nm across.
Credit: Science
False-colored TEM shows silica glass melting (blue) and reforming (yellow), with a region actively rearranging atoms in between (red). Each ring of atoms is about 1 nm across.
 
False-colored TEM image shows solid (yellow) and molten (blue) silica glass, with actively rearranging atoms in between (red). Each ring of atoms is about 1 nm across.
Credit: Science

The structure of silica glass has been something of a mystery to scientists. Because of the disordered, amorphous nature of the material, researchers can’t construct a picture of its atoms by using X-ray crystallography as they can with bulk crystals. Instead, an international team led by David A. Muller of Cornell University and Ute Kaiser of Germany’s University of Ulm devised a high-resolution transmission electron microscopy (TEM) method to get an atomic-scale glimpse of this material in motion and used it to study sheets of glass just two atoms thick (Science 2013, DOI: 10.1126/science.1242248). With that technique, the researchers recorded images of the glass as it deformed upon changing from solid to liquid. The TEM images and video reveal “a complex dance” of silicon and oxygen atoms, according to the team. Ring structures open and close. Atoms swap places. The results will likely help scientists create a better picture of the atom dynamics in amorphous materials, which are ubiquitous. Silica glass, for example, can be found in semiconductors and optical fibers.

 
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