本研究利用一新型的有機無機混成濕度感測材料來製作阻抗式濕度感測器(Impedance-type humidity sensor),此一感測材料利用溶膠-凝膠法(Sol-gel process)將有機材料2-丙醯2-甲基丙烷磺酸(2-acrylamido-2-methyl-propane sulfonic acid, AMPS)與二氧化矽(silica gel)作一混成反應而得,之後再利用旋轉塗佈法將此感濕材料塗佈於印有一對梳型電極的氧化鋁基板製得所要的感測元件。 混成材料所形成的結構可增強濕度感測器所需要的抗水性能(Water-resistivity)及縮短偵測所需的反應時間等特性。在本實驗探討的參數範圍內,於鍛燒溫度180℃、膜厚20μm以及3.5克的水合TEOS添加量時有最佳的感濕特性。在阻抗分析儀(LCR meter)測試後,於25℃交流阻抗1kHz的條件下,感濕特性由35%RH至95%RH可達四個數量級以上;反應時間從95%RH變化至20%RH僅需10秒左右。此外,在溫度依數特性僅有0.17 %RH/℃的影響(由15至35℃),遲滯量(Hysteresis)也在1.5% RH以下。其後並利用熱重損失(TGA)、接觸角分析儀(Contact angle)以及掃描式電子顯微鏡(SEM)對混成結構與表面特性做更深入的觀察與探討。
In this study, the impedance-type humidity sensor was prepared by using organic-inorganic composite material and the performance as investigated. The 2-acryl amido-2-methyl-propane sulfonic acid(AMPS) was hybridized in the sol-gel process with silica gel(SiO2). This hybrid material was coated on the Al2O3 substrate with interdigited electrodes by using the spin coating method and was used as a sensing material. The hybrid sensing film could increase the water-resistance and decrease the response time (45s from 95% to 20% RH). On the basis of this study, the better humidity-characteristic device was manufactured by annealing temp of 180℃, thickness of 20μm, and 3.5g hydro-TEOS addition. The impedance varied more than four orders of the magnitude in the range of 35~95% RH under the 1kHz of AC at 25℃. The temperature dependence is only 0.17 %RH/℃ under 15~35℃ and the hysteresis was below 1.5%RH. Furthermore, the surface properties and hybrid structure of the humidity sensor were investigated by using the SEM、TGA and contact angle meter.