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A series of new fluoropolymer, poly(styrene-co-trifluoroethylmethacrylate) (poly-Sty_n-co-TFEM_m), with different composition ratios of Sty and TFEM units, is synthesized and applied to the matrix of an optical oxygen sensing probe using phosphorescence quenching of metalloporphyrins, platinum and palladium octaethylporphyrin (PtOEP and PdOEP), by oxygen. The phosphorescence intensity of PtOEP and PdOEP in poly-Sty_n-co-TFEM_m film decreased with increase of oxygen concentration. The ratio I₀/I₁₀₀ is used as a sensitivity of the sensing film, where I₀ and I₁₀₀ represent the detected phosphorescence intensities from a film exposed to 100% argon and 100% oxygen, respectively. For PtOEP in poly-Sty_n-co-TFEM_m film, I₀/I₁₀₀ ratios are more than 20.6 and large Stern–Volmer constants greater than 0.49%^-1 are obtained compared with PtOEP in PS film. For PdOEP in poly-Sty_n-co-TFEM_m film, on the other hand, large I₀/I₁₀₀ values greater than 188.7 are obtained. In both cases for PtOEP and PdOEP, I₀/I₁₀₀ values increased with increase of the number of TFEM units in poly-Sty_n-co-TFEM_m. The response times of PtOEP and PdOEP immobilized in poly-Sty₁-co-TFEM_2.50 films are 5.5 and 3.0 s on going from argon to oxygen and 90.0 and 143 s from oxygen to argon, respectively. These results show that PtOEP and PdOEP immobilized in poly-Sty_n-co-TFEM_m films are highly sensitive devices for oxygen.