Fabrication and characterization of the composite nanofibers of polyacrylonitrile/fluorescent core-shell silica particles with their potential use for anticounterfeiting purposes in the textile industry

Composite nanofibers of polyacrylonitrile/fluorescent core–shell silica particles were fabricated. Two different sizes of fluorescent core–shell silica particles were synthesized. The first one consisted of particles with the diameter of about 310 nm (Bigger size fluorescent core-shell silica particles [BFSPs]) and the other one had the diameter of about 166 nm (smaller size fluorescent core-shell silica particles [SFSPs]). The images obtained by scanning and transmission electron microscopy confirmed the synthesis of spherical and nearly uniform particles. However, some clusters of smaller unformed silica particles were observed, especially in SFSPs. The results of Fourier transform infrared spectra spectroscopy confirmed the linkage between silica and fluorescein isothiocyanate. Scanning electron microscopy images of the composite nanofibers showed that the shell had a uniform morphology; however, there were some points having a higher diameter, where the core–shell particles were located. The fluorescence microscopy images of the composite nanofibers also showed the fluorescence property of the composite nanofibers with bright spots on them, where the particles were located. The fluorescence intensity of the composite nanofibers was significantly increased with the enhancement of the pH value in the range of 4.00–8.00. The observed pattern of composite nanofibers under ultraviolet radiation suggested that these composite nanofibers could be applied as anticounterfeiting markers for special clothes as well as pH-sensitive parts in smart clothing.