Dynamic Colour Changes in Thermochromic Liquid Crystal Inks: Compatibility with Bacterial Nanocellulose for Sustainable Packaging Solutions

The aim of this study was to investigate the impact of the molecular structure of thermochromic liquid crystals (TLC) on colour change, with a particular focus on the application of TLC inks and bacterial nanocellulose (BNC) in smart packaging. The chiral nematic (cholesteric) structure of TLC pigments plays a critical role in their dynamic colour-changing properties, with a pronounced effect from red to blue as temperature increases, especially when applied to a black substrate. This research explores the compatibility of TLC inks and BNC through material interactions and colorimetric properties, focusing on smart packaging applications, indicator systems, and related fields. The results suggest potential use of TLC inks in intelligent and sustainable packaging solutions, where the combination of TLC inks with BNC, a natural, biodegradable, and eco-friendly material is favoured. In this study, TLC inks were screen-printed onto BNC based films and black uncoated paper. Spectrometric measurements were used to examine the influence of the chiral nematic structure of liquid crystal pigments on dynamic colour change. The results of the temperature-dependent colour play effect were validated using the communication mechanism developed in our previous research.