Metalloporphyrins immobilized in styrene–trifluoroethylmethacrylate copolymer film as an optical oxygen sensing probe

Abstract

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_mfilm decreased with increase of oxygen concentration. The ratio I₀/ I₁₀₀is used as a sensitivity of the sensing film, where I₀and I₁₀₀represent the detected phosphorescence intensities from a film exposed to 100% argon and 100% oxygen, respectively. For PtOEP in poly - Sty_n- co - TFEM_mfilm, I₀/ I₁₀₀ratios are more than 20.6 and large Stern–Volmer constants greater than 0.49%^-1are obtained compared with PtOEP in PS film. For PdOEP in poly - Sty_n- co - TFEM_mfilm, on the other hand, large I₀/ I₁₀₀values greater than 188.7 are obtained. In both cases for PtOEP and PdOEP , I₀/ I₁₀₀values 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_2.50films 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_mfilms are highly sensitive devices for oxygen.