Preparation and colorimetric response of an aldehyde-functionalized macrocyclic diacetylene-derived polydiacetylene

Abstract

Stimulus-responsive colorimetric materials have found great utility in a variety of fields including anticounterfeiting, display and sensor technologies. Herein, we describe a colorimetric polydiacetylene (PDA) that is generated by polymerization of the aldehyde-functionalized macmcyclic diacetylene, MCDA-CHO. UV irradiation of self-assembled MCDA-CHO generates a blue-color PDA, which undergoes a sequential blue-purple-brownorange color change upon heating. Interestingly, the PDA displays a remarkably high temperature reversible thermochromism between 30 (blue) and 180 degrees C (reddish-brown). In addition to displaying reversible thermochromism, polymerized MCDA-CHO can be employed for colorimetric differentiation between aromatic and aliphatic primary amines. Accordingly, a blue-to-reddish brown color change takes place when the PDA is exposed to primary aniline derivatives while no color change occurs in the presence of aliphatic primary amines. Infrared spectroscopic analysis confirms that this colorimetric selectivity is a consequence of the facile formation of imine groups through reactions of the aldehyde moieties in the PDA with anilines.