Platinum porphyrin embedded in poly(1-trimethylsilyl-1-propyne) film as an optical sensor for trace analysis of oxygen

Abstract

A highly gas permeable polymer, poly(1-trimethylsilyl-1-propyne) (poly(TMSP)), was applied as an optical oxygen sensing matrix using luminescence quenching of platinum octaethylporphyrin (PtOEP) by oxygen. PtOEP was homogeneously embedded in poly(TMSP) to give a mechanically tough film with a thickness of 10 μm. The luminescence intensity of PtOEP embedded in the poly(TMSP) film drastically decreased with an increase in oxygen concentration. The oxygen sensitivity of the film (I₀/I₁₀₀) was very high and estimated to be 225. The Stern–Volmer plot for the poly(TMSP) film-embedded PtOEP was obeyed at lower oxygen concentrations between 0 and 10% and the Stern–Volmer constant is estimated to be 5.7%⁻¹. The limit of oxygen detection was less than 0.3%. The response times of PtOEP embedded in the poly(TMSP) film are 3.6 s on going from argon to oxygen and 73.2 s on going from oxygen to argon, respectively. These results indicate that PtOEP embedded in the poly(TMSP) film is a novel optical sensing material for trace analysis of oxygen.