Development of thermochromic polyacrylic film contaiming polydiacetylene vesicles

Abstract

This thesis deals with preparation and study of the tunable thermochromic films for applications as thermal sensing label. The thermochromic films were prepared from a thermochromogen, poly(10,12-pentacosadiynoic acid) vesicles, embedded in copoly(methacrylic-acrylate) latexes. The temperature induced color transition of the films from blue to red was observed visually and by visible spectroscopy. A coalescing agent, texanol, was used to modify the latex that allow tuning of the color transition temperature (CTT) of the thermochromic films in the range of 0-70 °C. Crosslinking monomers, n-methylol acrylamide (nMA), glycidyl methacrylate (GMA) and ethylene glycol dimethacrylate (EGDMA), were used to enhance a film forming properties. The variation of methacrylic/acrylate monomer ratio also affected the film forming properties and the CTT of the thermochromic films. The correlation of the glass transition temperature and the CTT suggested that the color transition of the films involved not only the thermochromism but also the thermally induced mechanochromism and solvatochromism. This research work presents a convenient approach for preparation of tunable thermochromic films that can record temperature history by their irreversible color change.