Humidity Sensor Based on Keratin bio Polymer Film

This paper discusses and compares two planar capacitive humidity sensors with interdigitated and rectangular-spiral shaped. The sensors electrodes are covered by the material under test. In our case, the sensitive element of the sensor based on wool keratin polymer is elaborated in our laboratory. The morphological and structural characteristics of keratin thin film were analyzed by scanning electron microscopy, optic profilometer, Fourier transform infrared spectroscopy, X-ray diffraction and contact angle measurement. The obtained keratin films are highly hydrophilic, porous and rough surface. Humidity measurement results are presented, in particular sensitivity, hysteresis and response time. In conclusion, the fabricated sensors show very high sensitivity and small hysteresis, the highest sensitivity value is achieved by spiral electrodes. The porous and rough surface morphology and low-cost, indicate that keratin sensing material is the appropriate candidate for humidity sensing application.