Novel chitosan-ZnO based nanocomposites as luminescent tags for cellulosic materials

Novel chitosan-ZnO composites have been synthesized as luminescent taggants for cellulosic materials. The synthesized chitosan-ZnO nanospheres (CS-ZnO NS), chitosan-ZnO-oleic acid quantum dots (CS-ZnO-oleic QD) and chitosan-ZnO-oleic acid:Eu(3+) doped nanorods (CS-ZnO-oleic:Eu(3+) NR) were characterized by X-ray diffraction, photoluminescence spectroscopy, FTIR spectroscopy and transmission electron microscopy. The prepared luminescent CS-ZnO composites were used in printing paste and applied to different types of papers and textiles by using screen printing technique. The colorimetric values of the printed CS-ZnO-oleic acid and CS-ZnO-oleic:Eu(3+) showed that printing caused slightly change in color values. Scanning electron microscopy images and color values of the printed surface showed that CS-ZnO-oleic QD and highly luminescence CS-ZnO-olic:Eu(3+) NR are suitable for use as a printed security feature.