(337i) Characterization of Physical Aging Behavior of Polymer Brushes for Thin Film Applications

Polymer brushes are thin films that consist of polymer chains chemically attached to a substrate by one end. As such, both the grafting density (number of polymer chains per area) and the thickness can be controlled in polymer brushes. At sufficiently high grafting densities, polymer chains in a brush experience volume exclusion effects and are compelled to extend perpendicularly to the substrate, which can strongly influence thin film properties. Previous studies demonstrate that polymer brushes can possess enhanced glass transition temperatures, suppressed surface reorganization, and increased elastic moduli in comparison to spin-coated films. However, there has been little focus on studying the structural relaxation of polymer brushes. Structural relaxation results in changes in polymer properties, such as increased brittleness, reduced permeability, etc., which is often referred to as physical aging. It is of significant interest to elucidate the relationship between thin film morphology and physical aging to better design stable thin films for long-term use.

My work aims to elucidate the influence of morphology, specifically the molecular packing and thickness, on the physical aging behavior of thin films. Using ellipsometry, I show that the thickness of polymethylmethacrylate (PMMA) brushes does not make an impact on the physical aging rates. The thickness of PMMA spin-coated films, though, can strongly influence their physical aging rates at certain aging temperatures. In addition to graduate research, I am the president of the Association of South Asians at Princeton, where I organize initiatives to connect the broader Princeton community to cultural aspects of South Asia and its diaspora.

Prior to my graduate work, I received my bachelor’s degree in chemical engineering in 2018 from Penn State University. Following my undergraduate studies, I worked at Merck at the West Point, PA site as a Quality Assurance Associate Specialist. I conducted visual inspections of vials, syringes, and packages along with oversight for line clearances for vaccine manufacturing operations on rotational shift work.

Research Interests:

My post-graduation research goal is to transition into a research and development role at a pharmaceutical company.