The resistive-type polymeric humidity sensors were prepared from the copolymers of [2-[(methacryloyloxy)ethyl]dimethyl]propylammonium bromide (MEPAB), [2-[(methacryloyloxy) ethyl]-2-hydroxyethyl]dimethylammonium bromide (MEHDAB), n-butyl methylacrylate (MBA), 2-hydroxyethyl methylacrylate (HEMA) and styrene. Four kinds of copolymers, ie, MEPAB/styrene/ MEHDAB, MEHDAB/BMA/HEMA, MEPAB/BMA/MEHDAB, and MEPAB/styrene/HEMA crosslinked with blocked-isocyanate on the Ag/Pd electrode/alumina substrate showed good durability at high humidities. The various electrical properties such as frequency dependency, temperature dependency, hysteresis, response time and water durability were examined. In the case of copolymer MEPAB/ BMA/MEHDAB＝3/6/1, the resistance was varied from 2.9 M to 1.84 k at 25 ℃ in the range of 30∼90%RH and this copolymers showed a good linearity and low hysteresis.

고분자막 저항형 습도센서를 제조하기 위하여 [2-[(methacryloyloxy)ethyl]dimethyl]propylammonium bromide(MEPAB), [2-[(methacryloyloxy)ethyl]-2-hydroxyethyl]dimethylammonium bromide (MEHDAB), n-butyl methylacrylate(BMA), 2-hydroxyethyl methylacrylate(HEMA)와 styrene의 공중합체를 사용하였다. 4가지 종류의 공중합체들 즉 MEPAB/styrene/MEHDAB, MEHDAB/BMA/HEMA, MEPAB/BMA/ MEHDAB 그리고 MEPAB/styrene/HEMA을 알루미나 기판에 인쇄된 Ag/Pd 전극 위에 blocked-isocyanate 가교제로 가교시켜 도포하였을 때, 매우 좋은 내수성을 보여주었다. 습도센서의 상대습도에 대한 주파수 의존성, 온도 의존성, 히스테리시스, 응답속도 그리고 내수성을 평가하였다. MEPAB/BMA/MEHDAB＝3/6/1 공중합체의 경우, 30∼90%RH 범위에서 2.9 M 에서 1.8 4 k 의 저항을 보여주었으며 좋은 직선성과 낮은 히스테리시스를 보여주었다.

Keywords: humidity sensor; 3-component copolymers; ammonium salt; isocyanate crosslinker