Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Real-time Spectral Birefringence Technique to Determine Polymer Morphology" By Megan Froshey Purdue MSE Ph.D. Preliminary Exam Advisor: Professor Mukerrem Cakmak ABSTRACT It is difficult to predict complicated viscoelastic polymer responses when subjected to mechanical deformation. One way to measure microstructural changes during these processes is to pass white light through the sample and measure its retardation over time. The difference in chain orientation in axial directions affects how light interacts with the polymer sample, and converting this retardation to birefringence provides a way to quantify changes in polymer chain orientation. Historically, systems used to measure birefringence of polymers were very simple and led to various errors, such as human interpretation of results. Furthermore, they were not able to provide precise, quantitative results and never before were able to track polymer properties in real time. This presentation discusses the development of real-time spectral birefringence technique to quantify microstructure of polymers- a novel way to quickly and accurately measure changes in polymer structure while undergoing complicated processing steps, simulating those in industry. This technique can be applied to any situation in which polymers are subjected to thermal or mechanical stresses - such as film orientation, annealing, and drying - and has the goal of providing constitutive relationships between mechanical and optical properties of polymers to allow for prediction and control of polymer morphology. Important applications include biaxial film orientation, used in capacitors and food packaging, as well as novel technologies such as photovoltaics and wearable health sensors. Date: Tuesday, October 3, 2017 Time: 1:30 P.M. Place: ARMS 1109