Effect of ultra-violet (UV) degradation on polyvinyl fluoride (PVF) films: investigating structural, thermal, surface, and mechanical properties

What is it about?

This paper investigates the effect of UVC irradiation on the structural, thermal, mechanical, and surface properties of polyvinyl fluoride (PVF) films. To achieve this, PVF films were characterized using Raman and FTIR spectroscopy, x-ray diffraction (XRD), Differential Scanning Calorimetry (DSC), Nano-indentation, optical profilometer, and x-ray Photoelectron Spectroscopy (XPS). Raman and FTIR spectroscopy revealed significant changes in band intensities, indicating alterations in the chemical structure, such as crosslinking and chain scission and oxidation. XRD analysis confirmed these findings, showing changes in microstrain consistent with the shifts observed in Raman bands. FTIR spectra also showed the formation of carbonyl (C=O) and C=C stretching groups, indicative of oxidation and photodegradation processes. DSC analysis revealed that crystallinity and Tg increased up to 72 h of exposure, after which both decreased. These changes in crystallinity indicate a complex interplay between chain scission and cross-linking mechanisms. Mechanical testing demonstrated corresponding trends in hardness and Young's modulus, aligning with changes in crystallinity. Surface roughness increased, while the contact angle decreased, indicating enhanced hydrophilicity with prolonged UVC exposure, attributed to photo-oxidation. XPS analysis highlighted significant surface chemical changes, including an increased O/C ratio due to photo-oxidation, which correlated with contact angle and FTIR findings.

Featured Image

Photo by Ayush Kumar on Unsplash

Photo by Ayush Kumar on Unsplash

Why is it important?

Our study explores a critical knowledge gap in polymer degradation by investigating the impact of UVC radiation on polyvinyl fluoride (PVF) films. While fluoropolymers have been extensively studied, research specifically focusing on PVF degradation mechanisms remains limited. Existing studies often examine laminated materials or different degradation conditions, leaving a lack of direct insight into PVF films themselves. By analyzing changes in structural, mechanical, thermal, and surface properties under controlled UVC exposure, our work provides valuable new insights into how PVF films degrade. These findings are essential for improving the longevity and reliability of PVF-based materials in solar panels, protective coatings, and other outdoor applications where UV exposure is a key concern. This research could lead to material innovations, help optimize PVF formulations, and contribute to enhancing the lifespan of photovoltaic (PV) components. Whether you're a researcher, engineer, or industry professional, our findings offer crucial knowledge for advancing durable polymer materials.