Study of UV-induced surface modification of polyethylene and polytetrafluoroethylene

Surface modification of polymers is essential for improving their interfacial properties without compromising bulk performance. This study investigates the effects of ultraviolet UV irradiation on the surface characteristics of polyethylene PE and polytetrafluoroethylene PTFE with the objective of understanding the relationship between UV-induced surface modifications and changes in wettability, chemical composition, and morphology. PE and PTFE samples were exposed to controlled UV treatment, and their surface properties were analyzed using water contact angle WCA measurements, Fourier-transform infrared spectroscopy FTIR, and atomic force microscopy AFM. Results showed that UV treatment led to a significant decrease in the water contact angle of PE, with a 106% reduction, reflecting an increase in hydrophilicity. In contrast, PTFE exhibited a more moderate 60% decrease in WCA, indicating limited enhancement in wettability. FTIR analysis revealed the formation of oxygen-containing functional groups in both polymers, with PE showing a more pronounced incorporation of these groups. The surface roughness of PE increased by 180%, from 42 nm to 118 nm, whereas PTFE showed a more modest increase of 89%. The AFM analysis confirmed a significant increase in nanoscale roughness for PE, while PTFE exhibited minimal morphological changes. This comparative analysis highlights the strong influence of polymer chemistry on UV-induced surface modification mechanisms. These findings demonstrate that PE is more responsive to UV irradiation, with significant alterations that lead to enhanced surface energy and wettability. In contrast, PTFE, due to its stable C-F bonds, undergoes slower and more limited modifications, primarily in the chemical domain. The study underscores the importance of material selection for applications in UV-rich environments, with PE being more suitable for applications requiring enhanced hydrophilicity, while PTFE is better suited for environments requiring UV durability. The insights gained from this work can be directly applied to the development of advanced coatings, adhesion technologies, and biomedical interfaces.