Stable polydiacetylene/ZnO nanocomposites with two-steps reversible and irreversible thermochromism: The influence of strong surface anchoring

Abstract

This contribution introduces a versatile method to prepare a new class of polydiacetylene(PDA)-based material. ZnO nanoparticle is used as a nano-substrate for spontaneous assembling of diacetylene monomer, 10,12-pentacosadiynoic acid, on its surface. An irradiation of the organized assemblies by UV light results in PDA/ZnO nanocomposites with deep blue color. Strong ionic interaction and hydrogen bonding at the ZnO surface restrict the dynamics of alkyl side chains and promote the PDA ordering, which in turn drastically affects its thermochromic behaviors. We have found that the PDA/ZnO nanocomposite exhibits two-steps color transition upon increasing temperature. The first transition of the nanocomposite in aqueous suspension, causing the color change from blue to purple, occurs reversibly at ∼90 °C. The transition temperature shifts to ∼100 °C when the nanocomposite is embedded in polyvinyl alcohol matrix. Further increasing temperature to 145 °C induces the second transition, which causes irreversible color change from purple to red. © 2011 Elsevier Inc.