TIME-DEPENDENT THERMOCHROMIC AND ELECTRICAL SIGNATURES IN MALACHITE GREEN–PVA FILMS FOR SUSTAINABLE ANTI-COUNTERFEITING APPLICATIONS

Abstract

Packaging counterfeiting is a big challenge faced by the industries that are looking for novel, secured, and green solutions. The objective of this work was to prepare and thermally treat Malachite Green doped polyvinyl alcohol (PVA) multi-mechanism functional films with a view to sensing application, primarily for anti-counterfeit packaging. The materials had showed tuneable optical and electrical properties, and three domains were observed where transition occurs, namely green (1–14 min), pink (15–32 min), and yellow (33–120 min). The changes are due to the reversible noncovalent interactions between hydroxyl groups of PVA and functional groups of the Malachite Green which dissociate slowly with the heat and do not modify the PVA structure. The finding were systematic shifts in wavelength observed through UV-vis Spectroscopy along with change in significance with I-V measurement. We made models to help predicting wavelength and conductance shifts against thermal treatment duration. These results prove Malachite Green-doped PVA films are eco-friendly materials that are customizable for anti-counterfeiting technology. This work fills in the gap of knowledge on the thermal effects on of dye-polymer systems. Additionally, the creditable and scalable work offers sustainable packaging with advanced security features.