Luminescent cotton fibers coated with fluorescein dye for anti-counterfeiting applications

A simple, rapid and green method to develop fluorescent cotton yarns was established. We report the application of fluorescein (FL) into textile support by impregnation method while keeping the original cotton yarn properties for anti-counterfeiting applications. The FL-coated yarns were characterized by Scanning Electron Microscopy, reflectance and fluorescence spectroscopy. The CIE chromaticity diagram showed a yellowish green emission with a weak yellow coloration of cotton fiber. Mechanical characterization of samples shows that the application of fluorescein did not alter significantly the breaking strength and elongation at break of the fibers, even when using resins. In contrast, to resin-free impregnation process the color fastness test demonstrates that the use of resins as binder is required. The obtained results showed that cotton samples release slowly its contents and fluorescein remains more than five washing cycles.