AuNP-decorated textile as chemo resistive sensor for acetone detection

This paper presents the development of chemo resistive sensors for the detection of volatile organic compounds (VOCs). The proposed sensor is based on citrate-functionalized gold nanoparticles (AuNPs) serving as a sensitive layer deposited on cotton fabric. Impedance variations due to VOC/substrate interaction are used as a detection principle. Specifically, this work focuses on acetone detection after exposing the AuNP-decorated cotton to a CH3COCH3 aqueous solution. Such an interaction resulted in a reduction of the total impedance (i.e., magnitude) of the system. This behavior can be ascribed to Van der Waals forces existing between the C=O group and the citrate moieties adsorbed on the gold nanoparticles, which favor charge injection to the substrate. Response to water was also tested for comparison, assuring that the solvent interacts with the sensitive layer by a different adsorption mechanism, not influencing the overall results. Sensor selectivity was also verified by considering ethanol (representative of alcohol group). Indeed, impedance curves reflect the different type of chemical interaction between the analyte and the substrate. In addition, sensor limit of detection for acetone was found to be 1% v/v, in the considered frequency range. Furthermore, sensor performance in terms of reusability was evaluated, showing that the Au-cotton ability in VOCs detection could be restored after about 90 min with a percentage up to 97 % in the frequency of 1Hz. These results can be considered the starting point for the development of portable, sensitive and user-friendly devices.