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采用羟乙基纤维素(HEC)和导电炭黑并添加山梨醇增湿剂制备碳湿敏膜,研究了膜在偏离结露区的非线性感湿特性和导电机理.扫描电镜观测到,膜中炭黑粒子形成网链状的空间导电结构;2%炭黑含量使膜的导电通路处于渗流区,膜电阻在80%RH附近对湿度有较强的非线性特性.分析I-V曲线认为,是导电网链中炭黑粒子的间距使膜电阻对湿度变化和测量电压的变化都非常敏感,非线性感湿特性与导电机理密切相关.复阻抗谱表明,碳湿敏样品在33%RH时只出现与炭黑体电阻有关的半圆弧,在80%RH时出现与炭黑粒界电阻有关的第二个半圆弧,92%RH时的复阻抗谱是以上两个半圆弧外加接近45o角的拖尾,拖尾部分对应膜与电极之间水分子引起的极化作用.
The carbon wet film was prepared by using hydroxyethylcellulose (HEC) and conductive carbon black with addition of sorbitol wetting agent to study the nonlinear wet sensitivities and electrical conduction mechanism of the film in the dew condensation area. Scanning electron microscopy Carbon black particles form a chain-like space conductive structure; 2% carbon black content of the membrane conductive pathway in the seepage area, the membrane resistance at 80% RH near the humidity has a strong nonlinear characteristics of the analysis of the IV curve that is The distance between the carbon black particles in the conductive network chain makes the membrane resistance very sensitive to the change of humidity and the change of the measuring voltage, and the non-linear wet-sensitive property is closely related to the conduction mechanism. The complex impedance spectroscopy shows that the carbon- Appears semicircular arc related to the black body resistance, the second semicircular arc appears at 80% RH, which is related to the resistance of the carbon black grain boundary, and the complex impedance spectrum at 92% RH is the above two semicircles plus nearly 45o Angle of the tail, the tail part of the membrane and the electrode corresponds to the polarization between the water molecules.