Abstract:

In order to obtain a humidity sensor with both good humidity response and color visibility, the CoCl₂/FP composite film was prepared by simple soaking-drying method using cellulose filter paper (FP) and cobalt chloride (CoCl₂) as raw materials, filter paper as the sensor's base material, and cobalt chloride as moisture sensitive material and color indicator. The physical and chemical properties of the composite films were tested by scanning electron microscope, Fourier infrared spectrometer and X-ray diffractometer. The results indicated that Cl and Co were uniformly distributed on the CoCl₂/FP composite film, and the main physical changes occurred between the filter paper and cobalt chloride. The current response and visible spectrum of CoCl₂/FP colorimetric humidity sensor were measured by electrochemical workstation and computer color matching instrument. The results showed that the CoCl₂/FP colorimetric humidity sensor had an obvious current response in the range of 11%~98%, and the current change was more than 1000 times. In addition, from low humidity to high humidity, CoCl₂/FP colorimetric humidity sensor presented a reversible color change from blue to red.

Key words: colorimetric humidity sensor, film, cellulose paper, cobalt chloride, desorption, chromatography

摘要：

为了获得兼具良好湿敏响应和颜色可视性的湿度传感器，以纤维素滤纸（FP）和氯化钴（CoCl₂）为原料，滤纸为传感器的基底材料，氯化钴为感湿材料和颜色指示剂，通过简单的浸泡-干燥的方法制得CoCl₂/FP复合膜。采用扫描电子显微镜（SEM）、傅里叶红外光谱仪（FTIR）、X射线衍射仪（XRD）对复合膜进行一系列物理化学性能测试。结果表明，CoCl₂/FP复合膜上均匀地分布着氯（Cl）元素和钴（Co）元素，且滤纸和氯化钴之间主要发生的是物理变化。采用电化学工作站和电脑配色仪对CoCl₂/FP比色湿度传感器进行电流响应测试和可见光光谱测试。结果表明，在相对湿度（RH）为11%~98%的范围内，CoCl₂/FP比色湿度传感器具有明显的电流响应，电流变化超过1000倍。另外，从低湿度到高湿度，CoCl₂/FP比色湿度传感器呈现出由蓝色到红色的颜色变化，且这种颜色变化是可逆的。

关键词: 比色湿度传感器, 膜, 纤维素纸, 氯化钴, 解吸, 色谱