The Use of Carbon Nanoparticles for Inkjet-Printed Functional Labels for Smart Packaging

Abstract

Smart packaging functions can be provided by printing functional labels onto packaging materials using inkjet printing and inks with changeable photoluminescence properties. Carbon nanoparticles are considered a perspective fluorescent component of such inks. Ink compositions based on carbon nanoparticles are developed and adapted for inkjet printing on paper packaging materials for producing smart packaging labels. The influence of technological factors of the printing process on the photoluminescence characteristics of the printed images is investigated. The main investigated factors are the concentration of carbon nanoparticles, the relative area of raster elements of a raster field of a tone image, the absorbance and surface smoothness of paper. The resulting parameters are photoluminescence intensity and color. It is found that in case of changes in surface smoothness and absorbance of paper and concentrations of carbon nanoparticles in the ink compositions, the photoluminescence intensity of a printed image changes while its photoluminescence color remains the same. To obtain the highest contrast of tone inkjet-printed images with carbon nanoparticles on papers with any absorbance, the highest concentration of carbon nanoparticles in the ink composition should be used. However, the highest contrast and the highest own photoluminescence intensity of a tone inkjet-printed image with inks with carbon nanoparticles can be achieved only on papers with the lowest absorbance. The most noticeable difference between photoluminescence intensity of printed images on papers with any absorbance can be obtained with the lower concentration of carbon nanoparticles in the ink composition (10 mg/mL). The optimum concentrations of carbon nanoparticles in the composition are determined: for papers with low absorbance—10 mg/mL, and for papers with medium and high absorbance—25 mg/mL. Analytical dependency is created for photoluminescence intensity of images printed with inkjet printing inks with carbon nanoparticles as a function of the studied technological factors. Some design solutions for photoluminescent labels are suggested.