The humidity sensor containing ammonium salt was prepared from the copolymer of 2-methacryloxyethyl dimethyl 2-hydroxyethyl ammonium bromide (MDHAB)/MMA/DAEMA = 6/3/1. The humid membrane was fabricated on the gold/alumina electrode by dipping. The impedances were 298kΩ, 11kΩ, and 2.3kΩ at 40%RH, 70%RH and 90%RH, respectively, at 5℃ and the humidity-sensitive characteristics were suitable for low temperature humidity sensor. The temperature-dependent coefficient between 5℃ and 20℃ was found to be -0.80%RH/℃ and the hysteresis falled in the ±2%RH range. The response time was found to be 38 sec for the relative humidity ranging from 34%RH to 88%RH at 20℃. The reliabilities such as temperature cycle, humidity cycle, humidity cycle, high temperature and humidity resistance, electrical load stability, stability of long-term storage and water durability were measured and evaluated for the application as a humidity sensor.

암모늄염을 포함하는 고분자 습도센서를 2-methacryloxyethyl dimethyl 2-hydroxyethyl ammonium bromide (MDHAB)/MMA/DAEMA = 6/3/1의 공중합체로부터 제조하였다. 감습막은 금/알루미나 전극에 침적법에 의하여 도포하였으며 5℃, 40%RH, 70%RH, 그리고 90%RH에서 전형적인 임피던스는 각각 298kΩ, 11kΩ, 그리고 2.3kΩ을 나타내어 감습특성은 저온에서 사용되는 습도 센서로서의 특성에 적합하였다. 온도 의존성 계수는 5∼20℃에서 -0.80%RG/℃이었으며 히스테리시스는 ±2%RH 이내에 존재하였다. 응답 속도는 34%RH에서 88%RH로 변화할 때 38초였다. 신뢰성 시험으로서 온도 사이클, 습도 사이클, 고온·고습 저항성, 전기 인가, 장기 방치, 그리고 내수성을 측정하여 습도센서로서의 응용성을 평가하였다.