Printability of nanocellulose-based inks and their application in anti-counterfeiting packaging

Abstract Inkjet printing has become an important technology for functional patterning in packaging, electronics, and security applications. In ink formulations, the binder plays a key role in determining rheological behavior and jetting stability, which directly affects print fidelity. In this study, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibrils (TOCNF) were employed as a sustainable binder for water-based inks due to their shear-thinning behavior and film-forming capability. Carbon quantum dots (CQDs) were incorporated into the TOCNF system to explore the feasibility of functional formulations for fluorescent anti-counterfeiting. Rheological analysis showed that the inks exhibited pronounced shear-thinning behavior and rapid viscosity recovery in the three-interval thixotropy test, enabling stable droplet formation during inkjet printing. Optimal jetting stability and printing resolution were obtained at a TOCNF concentration of 0.5 |wt% and an oxidation level of 10 mmol/g NaClO. The CQD-loaded inks produced high-resolution printed patterns with stable fluorescence, indicating the potential of TOCNF-based formulations for fluorescent anti-counterfeiting applications in packaging.