Identification, Assignment, and Characterization of Low-Frequency Dynamics in Microplastic Pollutants
Verhaeg, Emily A
Verhaeg, Emily A
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Abstract
As the use of single-use plastics is continuing to increase, the improper disposal of such materials is having an increased effect on the environment worldwide. These plastic products break down into millimeter-sized particles, known as microplastics, which make their way to various ecosystems. Combatting this problem begins with identifying the components of these pollutants, which can be done with vibrational spectroscopy. Among many polymers that are found in single-use plastics is cellulose, which can crystalize in a variety of forms. Probing low-frequency modes provides information about the crystal structures and bulk dynamics of the various constituents of these microplastics that near-infrared methods don’t reveal. FTIR spectroscopy probes solely intramolecular bonds and therefore cannot distinguish between these crystal structures. Low-frequency (terahertz) spectroscopy can provide insight into intermolecular forces and long-range lattice dynamics. Here, it is shown that the terahertz spectra of two forms of native cellulose are drastically different due to the organization of cellulose chains within each crystal, and the spectral features are assigned to vibrational modes using solid-state density functional theory.
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Graduate
Date
2021-01-01