Enhancing Oxygen Sensing Properties of Plasticized PVC Films by Blending Poly (Vinylidene Fluoride-Co-Hexafluoropropylene)

A convenient and less time-consuming approach for developing an optical oxygen sensing film with excellent balance between sensing performance and operating stability is addressed in the current work. In order to achieve better mechanical strength and resistance against ultraviolet (UV) degradation, a series of oxygen sensing films were prepared by embedding Pt (II) meso-tetra (pentafluorophenyl)porphine (PtTFPP) in the hosting copolymer matrices, which comprised different blending ratios of plasticized polyvinyl chloride (PVC) and poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) on polypropylene porous fiber membrane. The microstructure and optical properties of the sensing films were characterized by using scanning electron microscopy (SEM), laser confocal microscopy, and fluorescence spectrometer. Phase delay measurement under different oxygen partial pressure (PO
$_{{2}}\text {)}$
and temperature was conducted to evaluate the sensing performance and temperature compensation models of the sensing films for oxygen monitoring. Results show that the response time of the sensing films were all less than 10 s. The sensitivities and detecting ranges of the sensing films were increased and decreased with the reduction in PVC/PVDF-HFP ratio. When PVC/PVDF-HFP ratio reached 1:2, sensing film exhibits the best sensitivity of 0.334 kPa
$^{-{1}}$
and the smallest phase reduction rate of 0.0045°/h after 24 h of continuous irradiation by UV light, presenting a promising utilization potentiality in fields of gaseous oxygen detection.