A flexible low cost RH humidity sensor on plastic foil

Present work deals with the fabrication of flexible low cost thin film capacitive humidity sensor using Poly(methyl methacrylate) (PMMA) on interdigital copper electrodes over polyimide substrate for moisture measurement in RH range. The thin film of PMMA was deposited over electrodes using dip coating technique. The electrical parameters of the sensor at different humidity levels and frequencies have been determined by U1733C LCR meter (Agilent). The sensitivity of the sensor was found to be 0.218pF/%RH with response time and recovery time of 375 s and 245 s resp.