A bio-based curcumin copolymer for the detection of volatile amines

A copolymeric sensor containing Zn(II)-Curcumin derivatives as the sensing unit was developed via a bottom-up strategy. Specifically, a vinyl acetate/acrylic acid polymeric backbone was synthesized through radical bulk polymerization and covalently linked to Curcumin using a catalyzed esterification method, and the resultant system was subsequently metalated with Zn(II) cations. The Curcumin loading on the polymer backbone was approximately 2.22 %wt. The copolymers were characterized by Gel Permeation Chromatography,1H NMR, UV–Vis, and fluorescence spectroscopies, Thermogravimetric analysis, and Differential Scanning Calorimetry. The spectroscopic properties of the produced systems, deposited as solid-state thin films, were analyzed with Diffuse Reflectance UV–Vis Spectroscopy. The sensing capability was investigated via experiments involving volatile model pollutants (ethanol, toluene, acetone, ethylenediamine, pyridine, and ammonia), with the sensor thin films exposed to the headspace of a vial containing these pollutants. The sensor demonstrated sensitivity to model pollutants such as ammonia, ethylenediamine, and pyridine, while showing negligible variations to nonpolar and less nucleophilic species. The proposed methodology allows the development, including on an industrial scale, of a facile and cost-effective detector for polar volatile organic compounds. To the best of our knowledge, this represents the first application of Zn-Curcumin derivatives within colorimetric sensing contexts.