Investigation of Vapor-deposited Glasses by Nanocalorimetry and Dielectric Relaxation

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

In this project funded by the Chemical Structure, Dynamics and Mechanisms program of the Chemistry Division, Professors Mark Ediger (University of Wisconsin-Madison) and Ranko Richert (Arizona State University) are studying organic glasses prepared by deposition from the gas phase. Glasses play an important role in modern technology. For example, many cell phone displays are organic light emitting diodes and organic glasses are the active layers in these devices. This project seeks to determine properties of glasses and this fundamental understanding may enable the production of improved glasses that are useful in applications. This project characterizes the properties of vapor-deposited glasses using nanocalorimetry and dielectric relaxation. Recent work has established that vapor-deposited glasses can exhibit very high kinetic stability and other unexpected properties. The researchers study the extent to which secondary relaxation processes in vapor-deposited glasses are suppressed as a sensitive indication of the perfection of packing in the glass. Deposition in the presence of a large electric field is being tested as a means of preparing glasses with even higher kinetic stability. In addition, the project seeks to understand why some organic molecules do not form highly stable glasses when vapor-deposited. The training of graduate, undergraduate, and high school students is being advanced through the integration of chemistry research and education activities. Each summer an educational outreach program is presented to high school juniors, most of whom are from groups that are underrepresented in engineering and science, to develop interest in science/engineering and skills required for success in college.