Luminescent polylactic acid and polysulfone electrospun fibers containing europium (III) complexes

In this work, luminescent composite fibers were prepared by electrospinning of polylactic acid (PLA) and polysulfone (PSU) solutions containing the europium complex Eu(tta)₃(phen) (tta = 2-thenoyltrifluoracetonato; Phen = 1,10-phe3nantroline). The structural and optical properties were investigated using scanning electron microscopy, transmission electron microscopy, Fourier transform-infrared spectroscopy, and fluorescence spectroscopy. Cylindrical PLA and ribbon-like planar PSU fibers were obtained. The Eu complex was dispersed in the PLA and PSU fibers in the form of crystals of irregular shape with sizes in the range of 150-300 nm and led both type of fibers to emit a bright red fluorescence under UV-illumination. FTIR analysis showed that the Eu-O bond is affected by the polymer matrices although there were no considerable interactions between them. Fluorescence spectra studies revealed that the coordination environment of the Eu³⁺ ion changed resulting in an increased calculated asymmetric ratio as compared with that of the Eu pure complex. These results suggest the potential of electrospinning to prepare luminescent polymers in which biodegradability could be a desired property.