Fig. 4From: Colorimetric Humidity Sensors Based on Electrospun Polyamide/CoCl2 Nanofibrous MembranesThe repeatability characteristic curves of QCM-based PA66/CoCl2·6H2O (50 wt%) NFM sensor for 5 cycles of RH adsorption–desorption a between 12.4 and 55.2% RH, b between 12.4 and 75.5% RH, and c between 12.4 and 97.2% RH. d Humidity hysteresis characteristic of QCM-based PA66/CoCl2·6H2O (50 wt%) NFM sensorBack to article page