本研究為製備1-（4-羧基苯基）-2,5-二甲基-1H-吡咯，並將此材料本身和加入不同電解質後之複合材料進行比較，探討所摻入離子對於濕度感測之差異性。當材料摻入強電解質LiOH、NaOH、KOH以及弱電解質K2CO3後，由於其解離常數以及所解離出的離子皆會有所不同，在高濕低濕時會有不同的反應情況，會對濕度感測產生不同之影響性質。而就實驗結果顯示，當1-（4-羧基苯基）-2,5-二甲基-1H-吡咯摻入0.1 M KOH以及0.05 M K2CO3後，會因K+ 離子的水合能力以及強、弱電解質於高、低濕時的反應特性，材料整體對於濕度感測而言，會具有靈敏度高、線性良好、濕滯情況佳的反應特性。而利用阻抗頻譜分析圖探討此濕度材料的傳導機制，由阻抗頻譜分析的結果可知在低濕狀態下為電子傳導機制，在高濕狀態下為離子傳導為主。就整體而言，1-（4-羧基苯基）-2,5-二甲基-1H-吡咯摻入KOH以及K2CO3可作為一種開發新型電阻式濕度感測元件的新穎性材料。
Novel impedance-type humidity sensors were made of 1-(4-carboxylic acid phenyl)-2,5-dimethyl-1Hpyrrole that was doped with KOH and K2CO3 salts. The humidity-sensing properties of 1-(4-carboxylic acid phenyl)-2,5-dimethyl-1H-pyrrole were improved by doping with two alkali salts (KOH and K2CO3), whose dissociation constants differed greatly from each other. The electrical properties of 1-(4-carboxylic acid phenyl)-2,5-dimethyl-1H-pyrrole that was doped with KOH or a mixture of KOH and K2CO3 were examined in detail and found to be functions of relative humidity (RH).Additionally,the effects ofthe salts on the sensing properties (linearity and sensitivity) were elucidated. The sensor that was made of the 1-(4-carboxylic acidphenyl)-2,5-dimethyl-1H-pyrrole/KOH/K2CO3 composite film exhibited favorable impedance, high sensitivity, good linearity, small hysteresis, a short response/recovery time, a weak dependence on temperature and high long-term stability over the humidity range studied. The sensing mechanismofthe 1-(4-carboxylic acidphenyl)-2,5-dimethyl-1H-pyrrole/KOH/K2CO3 compositefilmwas elucidated using impedance plots.
