Researchers at Tel Aviv University have succeeded in producing a new type of glass that retains its transparency but instantly melts when it comes into contact with water at room temperature.
The research results were published in the peer-reviewed journal Nature.
The research, led by doctoral student Gal Finkelstein-Zuta and Prof. Ehud Gazit of the Shmunis School of Biomedicine and Cancer Research in the School of Life Sciences and the Department of Materials Science and Engineering in the School of Engineering at TAU, could dramatically change the sustainability and cost of tools in numerous industries. Most notably, the discovery could revolutionize optics and electro-optics, satellite communications, remote sensing and biomedicine.
“In our laboratory, we study bioconvergence and specifically use the wonderful properties of biology to produce innovative materials,” explains Prof. Gazit. “Among other things, we study sequences of amino acids, the building blocks of proteins. Amino acids and peptides have a natural tendency to combine with each other and form ordered structures with a defined periodic arrangement, but during the research we discovered a unique peptide that behaves differently from anything we know: It did not form an ordered pattern, but an amorphous, disordered one that describes glass.”
How does the glass work?
The liquid glass exhibits very little order at the molecular level, but its mechanical properties remain solid-like. While glass is usually made by rapidly cooling heated materials and then freezing them in a crystallization process, TAU discovered that the aromatic peptide, consisting of a three-tyrosine sequence (YYY), spontaneously forms a molecular glass upon evaporation of an aqueous solution under room temperature conditions.
“The commercial glass we all know is formed by rapidly cooling molten materials, a process called vitrification,” said Gal Finkelstein-Zuta. “The amorphous, liquid-like arrangement should be fixed before it arranges itself in a more energy-efficient way, such as in crystals, and that requires energy—the glass must be heated to high temperatures and immediately cooled down. In contrast, the glass we discovered, which is made from biological building blocks, forms spontaneously at room temperature without the need for energy such as high heat or pressure. You simply dissolve a powder in water—just like making Kool-Aid—and the glass forms. For example, we made lenses from our new glass. Instead of going through a lengthy process of grinding and polishing, we simply dropped a drop onto a surface, where we control its curvature—and hence its focus—just by adjusting the volume of the solution.”
“This is the first time someone has succeeded in producing molecular glass under simple conditions,” said Prof. Gazit, “but no less important are the properties of the glass we have produced. It is a very special glass. On the one hand, it is very strong and on the other hand, it is very transparent – much more transparent than ordinary glass.”
“The normal silicate glass that we are all familiar with is transparent in the visible light range, the molecular glass we have developed is transparent deep into the infrared range. It is used in many areas, such as satellite technology, remote sensing, communications and optics.
“It is also a strong adhesive that can bond different types of glass together while repairing cracks that form in them. It is a combination of properties that no other glass in the world has and that has great potential in science and technology. And we have obtained all of this from a single peptide – a small piece of protein.”