Synthesis and Characterization of Polyaniline Thin Films by Electrodeposition as Functional Materials for Eucalyptus Oil Aroma Sensors from Various Commercial Brands

Eucalyptus oil has varying qualities due to differences in chemical compound content, requiring a simple and sensitive analysis method to distinguish its aroma. Polyaniline (PANI) is a stable conductive polymer that is easy to synthesize and has electrical properties that can be controlled through doping, making it a potential sensor material. In this study, a thin layer of PANI was synthesized on an ITO substrate through electrolysis using cyclic voltammetry. Its conductivity was then tested using a four-point probe method based on voltage changes and further characterized using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The results showed a nanofiber morphology that supports high conductivity and contributes to sensor sensitivity. Testing showed significant voltage changes in response to variations in eucalyptus oil volume, with the highest sensitivity of 6% at a volume of 1.5 mL. In addition, this sensor was able to distinguish between three brands of eucalyptus oil based on differences in voltage response, demonstrating its selectivity. This study proves the potential of PANI as a flexible and effective sensor for analyzing the quality of eucalyptus oil. HIGHLIGHTS A thin polyaniline (PANI) film was successfully synthesized using the electrodeposition method. Four points probe sensing was employed to evaluate different eucalyptus oil qualities from various brands. Voltage changes were monitored over time to investigate the sensing performance. The best result was observed with eucalyptus oil sample A, where PANI effectively distinguished between brands of different quality. GRAPHICAL ABSTRACT