Cellulose acetate fibers with fluorescing nanoparticles for anti-counterfeiting purposes

Abstract

This research concerns the incorporation of fluorescent nanoparticles into cellulose acetate (CA) fibers. The resulting fibers that appear to be white until exposed to a certain frequency of light. The target application for these nanoparticle-containing fibers and fabrics is in anti-counterfeiting technology for documents, currency and apparel. The fluorescing nanoparticles used in this study, Cornell dots (C dots), have a fluorescent dye-containing silica core surrounded by a silica shell. The fluorescence of these nanoparticles can be tuned to a specific wavelength between 350 and 800 nm. The reproduction of this fluorescence at a precise wavelength, for several different wavelengths in a fiber pattern, would be difficult for counterfeiters to duplicate. A solution of CA and C dots was spun into a non-woven fabric using electrospinning, while single fibers were spun using dry spinning techniques. The actual weight percent of nanoparticles spun into these fibers was verified using thermogravimetric analysis (TGA). The C dot containing non-woven fabrics and fibers were then characterized using scanning electron microscopy (SEM) and confocal microscopy. The tensile properties of the fabrics and fibers were tested using ASTM standards for textiles to assess the effect that C dot loading had on the mechanical properties of the nonwoven fabrics and fibers.