Oxygen detection using UV-activated electrospun poly(ethylene oxide) fibers encapsulated with TiO2 nanoparticles

A UV-activated oxygen indicator was developed in this study. The indicator was prepared by dispersing TiO₂ nanoparticles, glycerol, and methylene blue in poly(ethylene oxide) solution using aqueous ethanol as a solvent. The solution was electrospun or solvent cast to produce oxygen-sensitive fibrous membrane and continuous cast film, respectively. Sensitivity characteristics of the resulting indicators to UV irradiation and oxygen detection, at different component ratios, were evaluated. Scanning electron microscopy results show that the diameter of the electrospun fibers varied from about 350 to 1000 nm. The electrospun indicators were 4–5 times more sensitive to UV irradiation as compared to continuous film indicators prepared by casting, mainly due to morphological differences between the two poly(ethylene oxide) carriers. Increasing ethanol concentration of the electrospinning solvent enhanced the sensitivity of the indicator to UV irradiation. Moreover, the photo-bleaching step of the indicator was highly dependent on the active component ratios in the formulation. FTIR spectroscopy was employed to study the interactions between the active compounds in the indicator. This study demonstrated that electrospun TiO₂-based indicator could be promising for oxygen detection in modified atmosphere packaging applications.