Armalcolite nanocomposite: A new paradigm for flexible capacitive humidity sensor

In this paper, a unique Armalcolite-PDMS-based flexible capacitive humidity sensor is designed by using spin coating technique, which uses interdigitated gold (Au) electrode and ultrathin ( $\sim 80~\mu \text{m}$ ) flexible polyimide substrate. The structural and morphological properties of the Armalcolite nanocomposite are characterized by X-ray diffraction (XRD) and SEM. The electrical characterization of the Armalcolite-PDMS-based flexible capacitive humidity sensor is performed at 25 °C, followed by relative humidity ranging from 33% to 95% and frequency varying 102 Hz to 106 Hz. The experimental investigation reveals a fast response time (8.53 s) and recovery time (11.25 s). The developed sensor exhibits a reversible response with ultra-low hysteresis of 0.92%. The sensor response is recorded for 30 days to confirm its long-term stability. The sensing mechanism is studied using impedance plots obtained at different humidity environments. The excellent sensing performance of the developed sensor could be beneficial for the researchers working in the area of flexible humidity sensors.