Synthesis of polystyrene beads loaded with dual luminophors for self-referenced oxygen sensing

Dispersion polymerization has been successfully applied to synthesize monodisperse polystyrene beads loaded with SiOEP and PtOEP for self-referenced oxygen sensing. The polystyrene beads became larger in size as the concentration of initiator was increased due to the reduction of primary particles precipitated from the polymerization medium. The dual luminophors showed similar absorption spectra but two distinctive emission spectra with peaks at 580 and 650 nm for SiOEP and PtOEP, respectively. While the emission of SiOEP exhibited no response to oxygen, the luminescence intensity of PtOEP was monotonically dependent on the concentration of oxygen. From the Stern-Volmer plot, we observed a linear correlation between the intensity ratio of SiOEP at 580 nm to PtOEP at 650 nm and the concentration of oxygen, which could be used to reliably monitor the partial pressure of oxygen in a system.