Date of Last Revision
Chemical Engineering - Cooperative Education
Bachelor of Science
Date of Expected Graduation
The dynamics of polymer thin films have been demonstrated to be significantly altered from the bulk, but the origins of such differences are not well defined. In this work, we seek to understand the differences in the structural dynamics (or physical aging) of polystyrene (PS) through branching and other well defined architectures (comb and centipede). The aging dynamics of ultrathin films (< 30 nm) differ from relatively thick films (100-150nm) with linear PS thin films aging more rapidly than the relatively “bulk-like” thick films. Ellipsometric measurements are used to characterize the physical aging rate of the films. The change in film thickness and refractive index as the films are held below the glass transition temperature (Tg) provides a simple measure of the physical aging. In this study, four different architectures (linear, comb, 4 arm star, and centipede) will be investigated. For each PS architecture, the aging rate will be determined for film thickness ranging from 10nm to 100nm over aging temperatures from 65C to 95C. Preliminary investigation shows that the branching of the PS will decrease the aging rate.
Bryan D. Vogt
Brown, Gregory; Lewis, Elizabeth; and Vogt, Bryan D., "Impact of Chain Architecture on the Thickness Dependence of Physical Aging Rate of Thin Polystyrene Films" (2020). Williams Honors College, Honors Research Projects. 778.