Facile Fabrication and Analysis of Highly Sensitive PtTFPP/Carbon Black/Polystyrene Oxygen-Sensitive Composite Films for Optical Dissolved-Oxygen Sensor

Abstract

This research has designed and fabricated an oxygen-sensitive composite film, based on fluorescence quenching by oxygen, which can be applied in optical dissolved-oxygen sensor probes. The composite film is prepared by mixing polystyrene (PS) and indicator dye (platinum tetrakis pentrafluorophenyl porphine, PtTFPP). Tributyl phosphate (TBP) and common black pigment (i.e., carbon black, CB) are then added to enhance the oxygen permeability and specific surface area of the film and to increase its oxygen sensitivity. A nonionic surfactant (i.e., Triton X-100) is used to facilitate the uniform dispersion of carbon black within the PtTFPP/PS composite film, producing a highly oxygen-sensitive film. This research shows that the highest sensitivity (I 0 /I 100 ) is achieved at a weight ratio of 150:1 (PS/PtTFPP), with a linear correlation coefficient (R 2 ) of 0.9955. With the addition of 3 wt % TBP to PS, the sensitivity increases to 16.51, with an R 2 value of 0.9939. The addition of CB to this film increases the sensitivity further to 19.12 (R 2 = 0.9916). The above results show that the addition of TBP and CB can effectively enhance the oxygen sensitivity of the film. This study successfully fabricates an oxygensensitive compound film with high oxygen sensitivity and detection accuracy in a simple and cost-effective manner. The methods used in this study can be used for developing other highly sensitive sensors, which can be used in professional water-quality assessments for commercial purposes.