π-conjugated polymer/metal oxide colorimetric sensor film for rapid, real-time, and ppb-level detection of triethylamine

Abstract

Triethylamine (TEA), a well-known volatile organic amine widely used in hair-care products, medicine, textiles, fertilizers, and chemical production, is extremely harmful to human health. Therefore, there is a necessity for the development of a simple and effective system to detect TEA in a rapid and real-time manner. In this study, we have developed three different nanocomposites based on polydiacetylene (PDA)-coated metal-oxide nanoparticles (TiO₂-NC, Fe₂O₃-NC, and SnO₂-NC) that consist of N-hydroxy succinimide (NHS)-diacetylene and diacetylene co-assembly. All three nanocomposites successfully underwent topo-chemical polymerization under UV-light irradiation and subsequently exhibited a blue-to-red colour change upon exposure to TEA. The carbonyl carbon in the hydrophilic head group is more susceptible to nucleophilic attack by TEA due to NHS functionalization. Even though the reversible color transition of PDA in response to TEA was not successful, Fe₂O₃-NC in the aqueous phase displayed a stronger colorimetric response than the TiO₂ and SnO₂ nanocomposites, with a limit of detection of 86 ppb. Furthermore, the Fe₂O₃-NC immobilized on chitosan film facilitated naked-eye detection of TEA vapor, demonstrating its potential as a colorimetric film sensor for various real-world applications.