THIN FILM
RESEARCH
INTRODUCTION
I worked in BU's Atomic Membrane Lab studying how thin polymer films respond to pressure. The films were cast with arrays of microscopic wells etched into them, and the question was how these wells would deform when gas pressure was applied.
I used Atomic Force Microscopy to image the wells before and after pressurization, looking at how much the polymer bulged and how well it held its shape once the pressure was removed. The goal was to understand both the mechanical strength of the film and how impermeable it actually was to gas.
ENGINEERING WORK
I used AFM to map the surface topography of the wells at sub-nanometer resolution, which let me pick out exactly which wells were worth analyzing further before running mechanical property scans on them. For each sample, I imaged a well, pressurized it with nitrogen for about a day, then imaged the same well again to measure how much it had bulged.
Across 12+ annealed samples, bulge heights ranged from 40.9 nm to 197 nm, which told me how much the films were stretching under load and how consistent that behavior was from sample to sample. The bigger question was impermeability. If a film actually held the gas in, the bulge should stay put after I removed the pressure source. Instead, most samples deflated fast, losing their bulge within 24 to 90 minutes. That range was wide enough that I had to be careful not to treat one or two samples as representative of the whole batch.
