Conductive polymer modified with nematic liquid crystal doped with graphene oxide for highly sensitive acetone...

Acetone has been recognized as a critical biomarker for diagnosing and monitoring blood glucose levels in people having type II diabetes, and its measurement has been considered essential for maintaining human health. In this study, a highly sensitive gas sensor was developed in which a nanostructured polyaniline film was modified with a graphene oxide (GO)-doped nematic liquid crystal (NLC), and this composite layer was employed for acetone detection. The fabrication of the gas sensors was carried out through the electrosynthesis of polyaniline on interdigital electrodes (IDEs) under acidic conditions, after which the resulting films were modified using GO-doped NLC. Detection of chemical vapors was achieved by monitoring variations in the electrical resistance of the sensing layer, which were induced by orientational ordering transitions of GO and NLC, as well as by the absorption of analyte molecules onto LC droplets distributed across the polyaniline surface. The morphology of the polymeric films prior to and following modification was examined using scanning electron microscopy. The sensor responses (SRs) toward acetone were evaluated both in the presence and absence of GO, and enhanced sensitivity and improved selectivity toward acetone were observed when GO was incorporated. A detection limit of 0.27 ppm and a linear dynamic range of 1-10 ppm were obtained for acetone determination. Validating the method was carried out through the comparison of the sensor results with those obtained using gas chromatography.