Intimate Humidity Monitoring: Development and Performance Evaluation of Wearable Color-Electric Dual-Mode Humidity Sensor

Flexible wearable humidity sensors have seen significant development in healthcare fields. However, most sensors have only one electrical response mode with low visualization, thus limiting applications. Here, a wearable color-electric dual-mode linked-response humidity sensor was provided for intimate humidity monitoring. Specifically, nickel (II) iodide (NiI2) and polyacrylonitrile (PAN) were chemically treated and sodium hydroxide (NaOH)-modified, respectively. Subsequently, the modified NiI2 and PAN were configured into a spinning solution to fabricate humidity-sensitive NiI2/PAN membranes utilizing the solution blow-spinning method. Polyimide-based fork-finger electrodes were then laminated onto the humidity-sensitive NiI2/PAN membrane to assemble a wearable color-electric bimodal NiI2/PAN humidity sensor. The sensor was characterized by a fast response time (6.19 s) and recovery time (9.58 s), wide humidity-monitoring range (11–98