Irreversible Thermochromic Behavior in Gold and Silver Nanorod/Polymeric Ionic Liquid Nanocomposite Films

The novel application of gold and silver nanorods as irreversible thermochromic dyes in polymeric ionic liquid (PIL) nanocomposites is proposed here. These materials have been synthesized by anion exchange of an imidazollum baed PIL in a solution that also contained gold nanorods. This results in the entrapment of the nanobjects within a solid polymer precipitate. In this article, the effect of the temperature was studied in relation to the change of shape and, consequently color of the gold or silver nanorods within the films. For the nanocomposites studied here a maximum of two visual thermochromic transitions was observed for gold nanorods and up to three transitions were observed for silver nanorods.