Optical properties of multifunctional pigment embedded in polymer matrix

Abstract

The main objective of this doctoral dissertation is to prepare and analyse multifunctional pigments, which are composed of three component leuco dye-based thermochromic system encapsulated in melamine-formaldehyde polymeric envelope modified by a fluorescent probe. The dissertation is divided into two main research topics. The first topic is focused on proper colorimetric characterisation of bulk thermochromic systems using crystal violet lactone as the colour former, bisphenol A as the developer, 1-octadecanol and 1-tetradecanol as co-solvents. A series of thermochromic systems varying in molar ratio of their components was prepared. The colour change is further discussed in relation to physical and chemical changes observed by infrared spectroscopy and differential scanning calorimetry. The second topic is aimed on microencapsulation of chosen thermochromic system into melamine-formaldehyde resin and modification of the resin with Uranine and Acid Red 52 fluorescent molecules. The multifunctionality of the prepared pigments is clearly demonstrated. Potential applications could be their utilization as anti-counterfeiting patterns in security printing.