A Single Molecule Is Rewriting How Glass Gets Made

Keypoints:

• Published in Nature Materials by teams from TU Dortmund University, Paderborn University, the University of Duisburg-Essen and the University of Oxford
• The molecule is 1,10-phenanthroline, added while the material is molten
• It lowers the melting temperature and rearranges bonds around metal atoms
• Tested on cobalt-containing glasses and carboxylate-based frameworks
• Possible uses include catalysis, sensors, optoelectronics, gas storage and batteries

Glass-making has long followed a simple rule. Melt the material, cool it fast and accept the chemistry you started with. A research collaboration has now shown that one added molecule can change a glass's internal structure while it is still molten. The work appears in Nature Materials.

This is not window glass. The study used glasses derived from metal-organic frameworks (MOFs), which are materials built from metal centers connected by organic compounds. Prof. Dr. Sebastian Henke of TU Dortmund University led the study. The key ingredient is 1,10-phenanthroline.

The molecule does two jobs. As a flux, it lowers the temperature needed to melt the material. As a chemical agent, it binds to the metal atoms and partly displaces old bonds, which increases the number of neighbors around each atom. The researchers can control how much the structure changes by adjusting the amount added. Henke says the melt stops being a rigid intermediate state.

The lower temperature matters too. Some of these materials break down before they melt, leaving damaging impurities. Prof. Dr. Matthias Bauer of Paderborn University says the gentler process prevented harmful decomposition products in cobalt-containing glasses. Cleaner samples also make magnetic behavior easier to measure. The team used X-ray absorption spectroscopy and found the cobalt atoms kept their oxidation state while their surroundings changed.

The method also worked with carboxylate-based framework structures, which suggests it could apply to a wider range of glasses. The researchers point to future catalysts, sensors and optoelectronic devices, plus materials that control magnetism or light. The source gives no timeline for products, so this is early lab work.