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.

Ag nanoparticles are perspective for the use in ink-jet printed smart packaging labels in order to protect a customer from counterfeit or inform them about the safety of consumption of a packaged product via changeable luminescence properties. It is determined that, to obtain printed images with the highest luminescence intensity, using the most technologically permissible concentration of fluorescent component in the ink composition and applying inks to papers with the lowest absorbance are recommended. The highest contrast of a tone fluorescent image can be obtained on papers with high degree of sizing. It is found that the use of papers with low optical brightness agent (OBA) content with a wide range of luminescence intensity allows obtaining the same visual legibility of a printed nanophotonic label. The increase in the relative area of raster elements of an image leads to nonlinear increase in luminescence intensity of printed images in long-wave area of visible spectrum, affecting the luminescence color of a printed label. For wide industrial production of printed nanophotonic labels for smart packaging, the created principles of reproduction of nanophotonic images applied onto paper materials by ink-jet printing technique using printing inks containing Ag nanoparticles should be taken into account.

Smart packaging is becoming more popular on world market as a new type of packaging able to react to changes in a packaged product during storage and informs a customer about the safety of consumption of packaged food. This article investigates the main technological issues of the use of nanophotonic printing inks based on ZnO/SiO2 nanoparticles and polyvinylpyrrolidone (PVP) for printing active elements of smart packaging on paper substrates, concerning material properties and parameters of screen printing. It is determined that the use of ink compositions with medium content of ZnO/SiO2 nanoparticles allows obtaining blue-green and blue shades of luminescence color of screen printed images by changing ink layer thickness on papers with different contents of optical brightness agents (OBAs). The minimum content of ZnO/SiO2 nanoparticles in the developed fluorescent inks leads to blue luminescence colors regardless the contents of OBAs of the papers and ink layer thickness. The luminescence intensity is directly proportional to ink layer thickness and partly depends on the content of OBAs in the selected paper. In order to fabricate nanophotonic elements of smart packaging with predetermined photoluminescence properties, the influence of investigated factors on photoluminescence properties of printed nanophotonic labels should be taken into account.

Smart packaging becomes more popular as it increases the safety of food consumption by monitoring a packaged food state and informing the customer about it, for example, by visual reaction of a special label on its surface. Nanomaterials can provide the needed functionality to such labels. Application of ink compositions containing silver nanoparticles on paper materials by screen printing is quite promising. A special ink composition was developed based on Ag nanoparticles that possess changeable photoluminescence properties in contact with compounds that indicate food decay. The possibility of application of this ink onto the surface of paper-based materials via screen printing was studied. The influence of ink layer thickness, characteristics of paper materials (degree of sizing, content of optical brighteners), and content of the fluorescent component in the ink composition on photoluminescence properties of printed labels for smart packaging was investigated. It was determined how to choose proper values of these technological parameters in order to obtain high luminescence intensity and predetermined luminescence color of printed labels using the developed nanophotonic inks. The results of the study allow industrial production of functional labels for smart packaging with nanophotonic elements with the needed optical (photoluminescence) characteristics, as well as for protecting packaging from counterfeiting.