Stimuli‐responsive colorimetric polydiacetylene sensor in polar organic solvent

Abstract

Polydiacetylene (PDA) has been actively employed as sensing vehicles owing to its unique colorimetric feature upon environmental stimulation. Here, blue phase PDA has been constructed by topological polymerization of commercial diacetylene acid (DA) noncovalently modified by guest amines. Specifically, PDA including 1‐naphthylmethylamine noncovalently bonded on both sides exhibits long‐term stability in polar organic solvents. The stability of PDA depended upon both the structures of the DA and the guest molecule, underscoring a stabilizing mechanism dominated by noncovalent bonding and strong π–π interaction. Accordingly, the blue phase PDA shows a colorimetric response from blue to red upon exposure to stimuli influencing noncovalent bonding and π–π interaction, such as elevated temperature, the existence of acid or alkali at concentrations as low as 50 ppm. Therefore, the PDA developed in this study has the potential of serving as a colorimetric sensor for detecting subtle environment changes and especially for measuring the quality of polar organic solvents recovered from industrial effluent.