The spectral characteristics of biologically safe banknotes imprints varnished with addition of nanosized silver particles

Abstract

Billions of banknotes in their daily circulation are determined as one of the important spreading ways of thousands of different microbes among the world's population. Therefore, the main factors influencing the degree of microbiological contamination of banknotes are considered. The influence of varnishing technological parameters, in particular the type of varnish cure on the surface, anilox roll line count, and anilox roll transfer volume, on the resistance of banknotes contamination, was studied to determine the option of UV varnishing, which will be the most optimal to improve the resistance of banknotes against to contamination. Also, the innovative technological processes of banknote surface antibacterial protection are proposed, in a particular banknote surface coating with varnishes that include silver nanoparticles, which have great bactericidal action. Methods of synthesis and stabilization of silver nanoparticles in aqueous solutions and organic solvents used for the inclusion into water-soluble and UV varnishes are considered. Conditions for the inclusion of silver nanoparticles in water-soluble and UV varnish have been established. The morphology and spectral characteristics of the obtained silver nanoparticles were studied. The methodology of decolorization of aqueous solutions of silver nanoparticles was developed in the paper, it was proposed to use such polymers as polyvinylpyrrolidone and sodium polyphosphate to increase the stability of nanoparticles. The influence of varnish compositions - water-soluble and UV varnishes - on the stability and spectral characteristics of silver nanoparticles has been studied.