The Design and Growth Of Ultra-Stable Glasses

Time: Wednesday, December 4, 2019 - 10:30am - 11:30am
Type: Seminar Series
Presenter: Mark Ediger; Hyuk Yu Professor of Chemistry, University of Wisconsin- Madison
Room/Office: Dunham 107
J. Robert Mann, Jr. Engineering Student Center
10 Hillhouse Avenue
New Haven, CT 06511
United States

Department of Chemical & Environmental Engineering Seminar

Mark Ediger
Hyuk Yu Professor of Chemistry
University of Wisconsin- Madison

"The Design and Growth Of Ultra-Stable Glasses"

Glasses are generally regarded as highly disordered and the idea of “controlling” molecular packing in glasses is reasonably met with skepticism. However, as glasses are non-equilibrium materials, a vast array of amorphous structures are possible in principle. Physical vapor deposition (PVD) allows a surprising amount of control over molecular packing in glasses and can be used to test the limits of amorphous packing in two ways. PVD can prepare glasses that approach the limits of the most dense and lowest energy amorphous packings that are possible. The activation barriers for rearrangements in these materials are very high, giving rise to high thermal and chemical stability. In addition, PVD allows control over anisotropic packing in glasses. For rod-shaped molecules, for example, glasses can be prepared in which the molecules have a substantial tendency to stand-up or lie- down relative to the substrate. As these materials have applications in organic electronics, an important question is: How much anisotropic order can be added to a glass without destroying key technological advantages such as macroscopic homogeneity? The high density and anisotropic packing of PVD glasses can be explained by a mechanism that is “anti-epitaxial” as structure is templated by the top surface rather than by the underlying substrate.

Seminar at 10:30AM
December 4, 2019
Mann Student Center Dunham Lab
Refreshments at 10:00AM