An LC-type Flexible Wireless Humidity Sensor with Electrospun Isolation Layer

Traditional inductance–capacitance (LC) wireless humidity sensors have the problem of serious leakage and low quality factor at high humidity. This paper presents an LC-type flexible wireless humidity sensor with an electrospun polytetrafluoroethylene/polyvinylidene fluoride (PTFE/PVDF) isolation layer. The sensor based on graphene oxide (GO) was fabricated on a porous hydrophobic PTFE substrate. Measurements show a sensitivity of 6kHz/%RH and hysteresis of 15% over a range of 30-90% RH. The response and recovery time are 9s and 5s, respectively. Compared with the sensor without isolation layer, the developed sensors exhibit an improved average quality factor from 6.6 to 7.1 and an increased detection range from 30%-90% RH, which shows PTFE/PVDF isolation layer is able to effectively reduce the dielectric loss of GO, especially at high humidity.