High color stability and reversible thermochromism of polydiacetylene/zinc oxide nanocomposite in various organic solvents and polymer matrices

Polydiacetylene (PDA)-based materials exhibit color transition when subjected to external stimuli, making them attractive for sensing technology. The utilization of PDA-based materials can be largely extended by fabricating in different polymer matrices, which normally involves organic solvents as media. Recently, our group has developed PDA/zinc oxide (ZnO) nanocomposites, exhibiting reversible thermochromism in aqueous medium. In this contribution, we demonstrate that the PDA/ZnO nanocomposite can be dispersed in various organic solvents including 1,2-dichlorobenzene, chlorobenzene, toluene, ethanol, butanol, hexanol, chloroform and tetrahydrofuran. The color of pure PDA changes from blue to red in these solvents while the PDA/ZnO nanocomposite remains blue after 30 days. The color reversibility and color-transition temperature of the PDA/ZnO nanocomposite are hardly affected in these organic solvents compared to the system of aqueous medium. We further demonstrate that the PDA/ZnO nanocomposite can be embedded in common polymer matrices such as poly(styrene), poly(methyl methacrylate), poly(ethylene) and poly(vinyl alcohol) by using a simple mixing process. We have found that color reversibility of the PDA/ZnO nanocomposite depends on property of the polymer matrices and persists up to about 200. °C in some systems. The ability to prepare PDA-based materials in different organic solvents and polymer matrices is very important for their utilization in various applications.