Mechano- and solvato-fluorochromic chalcone and its water-based flexo-ink for anticounterfeit applications

Pigments with unique optical features are always sought after in realizing superior security features to protect authentic documents/products against forgery. The present study reports the synthesis of triphenylamine-naphthalene chalcone (TPA-NC) with fascinating optical features: solvato-fluorochromism, mechano-fluorochromism, and aggregation-induced emission. The flexo print obtained on UV dull paper using water-based eco-friendly UV fluorescent ink with TPA-NC as pigment displayed good adhesion, resistance to abrasion, light fastness, and favourable electrical parameter values, which could be well utilized in security documents and developing OTFTs in banknotes to prevent them from being forged. Moreover, the printed paper samples could impart superior features including solvent fugitiveness, penetrating fluorescence, and mechanical stimuli responsive variations in emission color for achieving multilevel security. The security ink prepared using the thermally stable and biocompatible TPA derivative could generate a robust platform for tamper-detection, validation of genuine documents/products and in marking technology. Moreover, an ultra-high radio frequency identification (RFID) antenna is designed to resonate at 2.35 GHz. The hybrid arrangement has steady radiation characteristics for electronic anticounterfeiting applications.