Self-powered humidity sensor based on polypyrrole modified melamine aerogel

In this study, a self-powered sensor based on polypyrrole modified melamine aerogel ([email protected]) was developed and evaluated for monitoring constant humidity and flowing moisture. This sensor has a flexible, ultralight and ultraporous structure, and could generate humidity-induced open-circuit voltage from the concentration gradient of the H+ ions. The [email protected] humidity sensor generated the voltage of 105 mV, when it was placed in an environment with constant humidity of RH 98%. The response and recovery time was 32 s and 13 s, respectively, as the humidity changed between RH 11% and RH 98%. Furthermore, the sensitivity of the self-powered humidity sensor was evaluated by assessing the moisture changes of the human skin, and the moisture from the human breath.