New humidity-sensitive monomer, N-methacryloyl-N'-ethyl-N'-propyl piperazinium bromide (MANEPPB) was prepared by the quaternization reaction of N-methacryloyl-N'-ethyl piperazine (MANEP) with 1-bromopropane. Polyelectrolytes derived from the copolymers composed of MANEPPB/MMA/AA=60/35/5, 70/25/5, 80/15/5, 90/5/5 and 95/0/5 were prepared for the humidity-sensitive membranes, which were fabricated on the gold electrode by dipping method and were crosslinked by reacting copolymers with aziridine crosslinker, trimethylolpropane tris(2-methyl-1-aziridinopropionate) (TTAP). When the resistance dependences on the relative humidity of the sensors were measured, it was found that the resistance varied three orders of magnitude between 20 and 90%RH, which was satisfied with the requirement for the common humidity sensor operating at ambient humidity. Their hysteresis, temperature dependence, frequency dependence, response and recovery time and water durability were measured and evaluated as a humidity-sensing membrane.

새로운 감습성 단량체인 N -methacryloyl-N'-ethyl-N'-propyl piperazinium bromide(MANEPPB) 를 N-methacryloyl-N'-ethyl piperazine(MANEP)와 1-bromopropane의 4차염화 반응에 의하여 합성하였다. MANEPPB/MMA/AA=60/35/5, 70/25/5, 80/15/5, 90/5/5 및 95/0/5 조성의 전해질 공중합체를 감습막으로 사용하기 위하여 제조하였다. 상기 감습액에 아지리딘 가교제인 trimethylolpropane tris(2-methyl-1-aziridinopropionate)(TTAP)를 혼합하여 금 전극 위에 침적법에 의하여 도포하고 가교반응을 진행하여 습도센서를 제조하였다. 상대습도에 대한 습도센서의 저항을 측정하였을 때, 20∼90%RH 상대습도 영역에서 10^(3)의 저항 값이 변화하였으며, 이것은 상용 습도센서로서 대기의 습도를 측정하는데 요구되는 특성을 보여주었다. 그 밖에 온도 의존성, 주파수 의존성, 히스테리시스, 응답 및 회복 속도 그리고 내수성을 측정하여 습도센서로서 특성을 평가하였다.

Keywords: humidity sensor; methacrylamide; piperazinium bromide; aziridine crosslinker; water durability.