Low-cost ZnO incorporated carbonized nitrile butadiene rubber (NBR) as a relative humidity monitoring sensor

This paper presents the development and characterization of a sustainable humidity sensor that is both cost-effective and high performing. The sensor utilizes a composite material comprising conductive carbon derived from recycled Nitrile Butadiene Rubber (NBR) gloves and zinc oxide (ZnO). Among the various chemical compositions tested, the sensor with a carbon-to-zinc oxide (C:ZnO) ratio of 1:0 exhibited superior humidity-sensing performance. The study encompassed a broad spectrum of relative humidity levels, ranging from 5% to 95% at room temperature (25 °C) at an optimum frequency of 100 Hz. The sensor exhibited remarkable characteristics, including a minimal hysteresis of only 0.36%, indicating its ability to provide consistent and accurate readings. Moreover, the sensor demonstrated excellent long-term stability, ensuring reliable performance over extended periods. Additionally, the sensor showcased rapid and dependable sensing capabilities, with a response time of 18 s and a recovery time of 16 s. This indicates its ability to detect and recover from changes in humidity levels promptly. The composite material's high sensitivity to relative humidity variations can be attributed to the presence of zinc oxide nanoparticles (NPs), which have an affinity for water molecules and facilitate interaction. To assess its performance, the developed sensor was compared to most previous work in the literature and the results revealed that the proposed sensor exhibits comparable levels of accuracy and reliability. This work provides a simple, cost-effective strategy for fabricating high-performance humidity sensors by exploring waste materials like NBR. © 2023 Elsevier B.V.