AFM-based Nanoindentation Technique: A Novel Approach to Determine the Nanoscale Degradation of PET

Overview

Roanoke Valley Governor’s School The purpose of this experiment was to investigate the impact of water type, movement, and sand on the degradation of polyethylene terephthalate (PET). It was hypothesized that if PET was exposed to distilled, spring, and ocean water, then atomic force microscopy (AFM) will be able to investigate the nanoscale degradation of PET using the novel technique of lithographybased nanoindentation. Two square 1 cm pieces of PET were treated in distilled, spring, and ocean water, along with shaking treatments for each water type with or without sand. The samples were individually placed in a 50 mL Erlenmeyer flask and treated for 19 days in the still (control) and shaking conditions. Force-distances produced by nanoindentation were obtained for each surface to investigate surface abrasion resistance of different water types on PET. Surface roughness from topography scans were used to determine the impact of shaking and sand. The alternative hypothesis, that at least one of the amounts of surface roughness was different from the others, was accepted. The p-value of ≤0.002 was statistically significant at the 5% significance level, indicating that the mean surface roughness of PET treated with all three types of water, sand, and shaking were not equal. Abrasion resistance values were calculated using depths obtained from topography scans after nanoindentation was performed, which indicated that when untreated PET (25.378 nN/nm) was exposed to each different water type, spring water treated PET (29.716 nN/nm) was the most susceptible to degradation in comparison to distilled (43.715 nN/nm) and ocean water (52.173 nN/nm).

Competition history

• JSHS 2020 Category not listed

Resources

• National JSHS abstract book ↗

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