MADISON - Look at your window - not out it, but at it. Though the window glass looks clear, if you could peer inside the pane you would see a surprising molecular mess, with tiny particles jumbled together any which way.
Now, researchers at the University of Wisconsin-Madison have developed a new glass-making technique that eliminates some of that mess. With the new technology, described in a study in the Dec. 8 issue of Science, they created a novel glass that is stronger and more stable than glass made in traditional ways. Though not suitable to replace everyday products like window panes or eyeglasses, this new glass may allow pharmaceutical companies the opportunity to explore previously unusable drug compounds.
When considered at the molecular level, most solid materials can be described as either crystals or glasses, explains lead author Mark Ediger, a UW-Madison chemistry professor. The difference lies in the degree of internal organization of their constituent molecules.
"A crystal is like toy soldiers all lined up marching together," Ediger says. "A glass is a teenager's room, with stuff packed in everywhere."
Just as levels of messiness can range from cluttered to chaotic, levels of molecular disorder can vary between different types of glass. Glasses composed of more organized molecules are more stable and durable, while glasses with haphazard molecular assemblies are less stable and may degrade over time.
Conventional glasses are relatively disordered and molecularly unstable because of how they are made. Glass ingredients are melted, then cooled and allowed to harden. As the molten glass cools, Ediger says, "The molecules slow down, then get stuck. The question is, did they get stuck in an organized state or in an unorganized state""
Normally, a piece of glass is allowed to cool all at once and the inner molecules, unable to move freely, tend to be trapped in disarray. Ediger and his team,
Contact: Mark Ediger
University of Wisconsin-Madison