In order to improve the luminescent stability of water-based anti-counterfeit ink, a new fluorescent material is prepared by doping dye into silica nanoparticles. Water soluble anionic dye 1, 3, 6, 8-pyrenesulfonic acid sodium salt (PTSA) is selected as the dopant. In this work, PTSA is successfully trapped into silica nanoparticles (SiNPs) by the reverse microemulsion method using cationic polyelectrolyte poly (dimethyl diallyl ammonium chloride; PDADMAC) as a bridge. The UV absorption spectra, fluorescence emission spectra and fluorescent decay curves are used to describe the luminescent properties of the PTSA-doped silica nanoparticles (PTSA-SiNPs). In addition, the as-prepared PTSA-SiNPs and polyurethane waterborne emulsion are used to prepare water-based anti-counterfeit ink, and fluorescent patterns are successfully printed through screen-printing. The samples printed by the ink exhibit desirable fluorescence properties, heat stability, robust photostability, and a fluorescent anti-counterfeit effect, which makes the PTSA-SiNPs promising luminescent materials for anti-counterfeit applications.

Abstract. Using sodium dodecyl sulfate/isoamyl alcohol/n-heptane/water as reaction medium, copper chloride as precursor, Sodium boron hydride as reducing agent, aniline hydrochloride as monomer, copper/polyaniline nanocomposite was prepared by the method of inverse microemulsion polymerization. The nano-composite was characterized by XDS, FTIR and TEM. The result of XDS confirmed that the copper/polyaniline composite contained the main elements of copper, carbon, nitrogen and had no oxygen. It was showed that the polyaniline could effectively prevent the nano copper from being oxidized. FTIR spectra of the material inferred polyaniline was successfully obtained by the polymerization. TEM image showed nanocomposite was core-shell structure, and its average particle size was about 30nm.