Measuring correlated dynamics in molecular glasses: Properties of molecular glasses change as they are made into nanometer sized films. Fakhraai and Riggleman showed that when the film thickness is reduced below 30 nm, the solid glass films become liquid-like and flow. This results in dewetting as shown in the figure.
Fakhraai and Riggleman studied correlation lengths in glassy systems using isothermal dewetting of thin films of molecular glasses along with glass transition temperature measurements. They showed that similar properties are observed in various polymeric films as well as inorganic glasses such as amorphous selenium (in collaboration with Richard Stephens).
Broader Impact
Girard College National Society of Black Engineers: Fakhraai group members Melissa Vettleson, Sarah Wolf, and Tiany Liu, along with undergraduate student Gabriel Angrand (organizer of the event and Pre-College Initiative Chair of Penn’s National Society of Black Engineers) participated in hands-on experiments and demonstration for high-school students. “This STEM Conference acts as a vehicle for middle school and high school members in the surrounding community to get exposure to the lab settings, practical experiments, scientific reasoning and procedure in collegiate institutions and generally begin thinking about opportunities they can pursue in their post high school paths".
Zahra Fakhraai (Chemistry), Karen Winey (Materials Science & Engineering), and Robert Riggleman (Chemical and Biomolecular Engineering)
Graduate student Sarah Wolf demonstrates optical cloaking to Philadelphia high-school students at an event organized by the National Society of Black Engineers.
