Spectroscopically Evaluating Composition and Crystallinity in Pristine and UV-Exposed PET Films Using Polarization-Dependent Optical Photothermal Infrared Microscopy.
4 affiliations
- 1Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland20899, United States.
- 2Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland20742, United States.
- 3Materials and Structural Systems Division, Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland20899, United States.
- 4Department of Chemistry, Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore, Maryland21218, United States.
Abstract
In this study, we used polarization-dependent photothermal infrared (OPTIR) microscopy to extend infrared (IR)-based methods to characterize structurally and chemically modified polymer films. Because of the reported relationship with polymer crystallinity and stability, methods capable of monitoring and estimating changes in crystalline regions are paramount for understanding the performance and fate. To develop PTIR methods that could advance the understanding of plastic and polymer degradation, we examined UV-irradiated polyethylene terephthalate (PET) films using simulated photodegradation via a high-energy radiant exposure (SPHERE) weathering device. The well-studied UV-irradiated PET system provided a model to expand the IR characterization capabilities. Previously reported IR methods for determining crystallinity in bulk PET through glycol conformer fractions were combined with advanced structural determination methods to characterize thick and opaque cross-sectioned films using azimuthal angles and Hermans in-plane orientation functions, which extended the sample types available for analysis. To demonstrate the opportunity to decouple signatures from chemical and structural modifications in changing and chemically heterogeneous films, heterogeneity mapping was reported as a function of depth in cross-sectioned films using two-trace two-dimensional (2T2D) correlation analysis coupled with K-means clustering. Faster imaging procedures were also developed to limit possible effects from sample degradation and instrument drift during the acquisition.
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BibTeX
@article{liberdamatyja2026spectroscopically,
title = {{Spectroscopically Evaluating Composition and Crystallinity in Pristine and UV-Exposed PET Films Using Polarization-Dependent Optical Photothermal Infrared Microscopy.}},
author = {Danuta Liberda-Matyja and Hsiu-Chin Huang and Tae Joon Cho and Li-Piin Sung and John Pettibone},
journal = {Analytical chemistry},
year = {2026},
month = oct,
doi = {10.1021/acs.analchem.6c01918},
url = {https://europepmc.org/article/MED/42916125},
note = {CC BY},
}
RIS
TY - JOUR
TI - Spectroscopically Evaluating Composition and Crystallinity in Pristine and UV-Exposed PET Films Using Polarization-Dependent Optical Photothermal Infrared Microscopy.
AU - Danuta Liberda-Matyja
AU - Hsiu-Chin Huang
AU - Tae Joon Cho
AU - Li-Piin Sung
AU - John Pettibone
PY - 2026
DA - 2026/10/01
JO - Analytical chemistry
DO - 10.1021/acs.analchem.6c01918
UR - https://europepmc.org/article/MED/42916125
AB - In this study, we used polarization-dependent photothermal infrared (OPTIR) microscopy to extend infrared (IR)-based methods to characterize structurally and chemically modified polymer films. Because of the reported relationship with polymer crystallinity and stability, methods capable of monitoring and estimating changes in crystalline regions are paramount for understanding the performance and fate. To develop PTIR methods that could advance the understanding of plastic and polymer degradation, we examined UV-irradiated polyethylene terephthalate (PET) films using simulated photodegradation via a high-energy radiant exposure (SPHERE) weathering device. The well-studied UV-irradiated PET system provided a model to expand the IR characterization capabilities. Previously reported IR methods for determining crystallinity in bulk PET through glycol conformer fractions were combined with advanced structural determination methods to characterize thick and opaque cross-sectioned films using azimuthal angles and Hermans in-plane orientation functions, which extended the sample types available for analysis. To demonstrate the opportunity to decouple signatures from chemical and structural modifications in changing and chemically heterogeneous films, heterogeneity mapping was reported as a function of depth in cross-sectioned films using two-trace two-dimensional (2T2D) correlation analysis coupled with K-means clustering. Faster imaging procedures were also developed to limit possible effects from sample degradation and instrument drift during the acquisition.
SN - 0003-2700
SN - 1520-6882
ER -