Fundamental Characteristics of Hydrophilic Polymer (Polyether Block Amide) as a Humidity Sensor

Abstract
Polyether block amide (PEBA), which is a hydrophilic polymer, was examined as a polymeric resistive humidity sensor. The PEBA has extremely high water absorbability and a high melting point, and is chemically stable. Humidity-sensitive thin polymer films for sensors were prepared by spreading a phenol solution of PEBA on alumina substrates with gold comb electrodes by means of a spinning method. The humidity-impedance characteristics of sensors show no hysteresis, good reproducibility and stability in long-term use. The time responses of the sensors are slow for humidification and very quick for desiccation compared with conventional sensors.