Polystyrene Beads Loaded With Luminophors: Synthesis And Oxygen Sensing Properties

Oxygen is one of the most materials in the world due to its high relevance to living things. We developed a series of fluorescent beads optical oxygen sensors by different methods. The fluorescence oxygen indicator dye Platinum octaethylporphyrin(Pt OEP) was wrapped in polystyrene spheres. The influences of particle size, dye-loading ratio, swelling system and p H buffer to properties of oxygen sensing were investigated.It is found that, the particle size of fluorescent beads prepared by soap-free emulsion polymerization increases with the increasing quantity of ethylene monomer. The value of I0/I100According to the experimental results, the surface morphology of fluorescent beads was severe damage when excess volume of sweller was added. The dye-loading ratio of fluorescent beads prepared by Tetrahydrofuran(THF) swelling absorption starts to rise then decreases. The peak value of dye-loading ratio is 51.06% when the volume ratio of THF and H of small particle size fluorescent beads is 4.5 which indicates better oxygen sensitivity. The intensity of fluorescence decays 9% by alternate blowing nitrogen and oxygen until saturated solubility. Under UV light for a long time, luminescent intensity weakens 5.2% even the fluorescent sphere emulsion was placed at least 90 days, which indicates the beads are stable.2O is 1:500. The dye-loading ratio of fluorescent beads prepared by Trichloromethane(CHCl3) swelling absorption starts to rise then decreases. The peak value of dye-loading ratio is 15.06% when the volume ratio of CHCl3 and 2-Propanol is 1:167. Two kinds of fluorescent beads swelled by THF and CHCl3 which display best swelling performance were selected to investigate their properties of oxygen sensing. The results show that the values of I0/I100 of two kinds of fluorescent beads are 4.00 and 1.52 respectively and quenching time of O2 are 16 s and 60 s respectively. Under UV light for 1 hour luminescent intensity of two kinds of fluorescent beads reduced by 2.2% and 2.1% respectively. Oxygen sensing properties of fluorescent spheres prepared via THF swelling procedure in different p H buffer were also studied thoroughly. Results indicate that peak position of fluorescence emission spectrum and the response sensitivity to O2 are stable which could not be affected by the interference of the medium environment. Cycle stability, light stability, excellent acid and alkali resistance are very good, and finally, the Stern-Volmer equation is established.At last, using fluorescent spheres as nanosensor, the dissolved oxygen content of water which were from fish tank, tap and river were measured to be 5.06, 6.36 and 12.05 mg/L respectively. There is no great difference between the experimental results and relevant literatures or the common sense of life, which shows that oxygen sensitive fluorescent beads have important potential applications used as photochemical oxygen sensor.