Stability and water-resistance of humidity sensors using crosslinked and quaternized polyelectrolytes films

Impedance-type humidity sensors using crosslinked and quaternized polyelectrolytes films were fabricated by dip-coating method, and their electrical and humidity-sensing properties have been investigated in the range of relative humidity (33–95% RH). The stability of these sensors was evaluated by exposing the sensors to various environments such as placing them in water and exposure to normal ambient for extended periods. The sensor was durable even after soaking in water for 1000 min. When the sensors were exposed to 80 °C and 100% RH for 24 h, the sensors still showed almost three orders of change, exhibited good stability at high humidity and high temperature. Surface morphology of the sensors were also measured and estimated at different conditions.