Novel nanofiber yarns synchronously endued with tri-functional performance of superparamagnetism, electrical conductivity and enhanced fluorescence prepared by conjugate electrospinning

Abstract

Novel one-dimensional [Fe₃O₄/PANI/PAN]//[Eu(BA)₃phen/PAN] (PANI = polyaniline, PAN = polyacrylonitrile, BA = benzoic acid, and phen = 1,10-phenanthrolin) heterogeneous nanofiber yarns synchronously endued with excellent tri-functionality of fluorescence, superparamagnetism and electrical conductivity were successfully fabricated for the first time using conjugate electrospinning. The heterogeneous nanofiber yarns are composed of [Fe₃O₄/PANI/PAN] electrical–superparamagnetic nanofibers and [Eu(BA)₃phen/PAN] fluorescent nanofibers, realizing effectively the isolation of dark-colored Fe₃O₄ nanoparticles (NPs) and PANI from Eu(BA)₃phen complexes, and thus enhanced fluorescence intensity is acquired. The morphologies and properties of the samples were studied in detail using X-ray diffraction, scanning electron microscopy, energy-dispersive spectrometry, four-probe testing, a vibrating sample magnetometer and an F-7000 fluorescence spectrophotometer. The results reveal that the prepared heterogeneous nanofiber yarns have a large aspect ratio and uniform diameter, and that the nanofibers in the yarns demonstrate high orientation. It is found that the superparamagnetism and electrical conductivity of the heterogeneous nanofiber yarns can be respectively adjusted by modulating the amounts of Fe₃O₄ NPs and PANI in the yarns, and the highest electrical conductivity reaches up to the order of 10⁻³ S cm⁻¹. More importantly, the fluorescence intensity of the heterogeneous nanofiber yarns is much stronger than that of the counterpart [Fe₃O₄/PANI/Eu(BA)₃phen/PAN] homogeneous nanofiber yarns with the same compositions and contents owing to the fact that the Fe₃O₄ NPs and PANI were not directly mixed with the Eu(BA)₃phen complexes. Furthermore, the design concept and preparation method provide an effective route for manufacturing other multi-functional nanofiber yarns.