基于AAO/PTFE复合薄膜封装的湿度传感器应用

Application Research of AAO/PTFE Composite Membrane Encapsulated Humidity Sensor

目的研究多孔阳极氧化铝/聚四氟乙烯（AAO/PTFE）复合薄膜应用于湿度传感器封装窗口的水蒸气输运特性和抗污染能力。方法通过旋涂法在双通阳极氧化铝薄膜上制备PTFE微孔膜,将该复合薄膜用作湿度传感器的封装窗口,在定温变湿的环境和油漆喷涂房中分析相对湿度测量的静态误差和动态响应,研究AAO/PTFE复合薄膜对传感器测量的影响和保护功能,并将其与PTFE和PVDF滤膜进行对比。结果定温变湿环境下静态和动态的测量结果表明,AAO/PTFE复合薄膜对湿度传感器造成的测量误差最大可达15%,且误差曲线可以分为30%~50%的低相对湿度区间、50%~80%的中相对湿度区间和大于80%的高相对湿度区间。静态测量的差异是由不同相对湿度区间内试验箱中空气流动速率不同造成的,而动态响应的差异主要源于不同区间内管壳内、外的相对湿度差不同。结论 PTFE薄膜的涂覆不仅保留了AAO滤膜优异的水蒸气输运性能,还有效提高了其表面抗污染能力。

The vapor transportation properties and surface anti-pollution abilities of AAO/PTFE composite membrane encapsulated humidity sensor were researched. PTFE thin films with porous structures were prepared on the bi-pass AAO template using spin coating method, and used on the package windows of the humidity sensor. The static error and dynamic response were studied to evaluate the influence and protective effect of the AAO/PTFE composite membrane on the sensors in environments with constant temperature and varying humidity and in paint room, which were then compared to those of PTFE and PVDFA films. According to static and dynamic response results from humidity sensor testing, the maximum relative error reached 15% in the AAO/PTFE composite membrane encapsulated humidity sensor and three regimes could be identified： low humidity regime（30%~50%）, medium humidity regime（50%~80%）, and high humidity regime（80%）. Different air flow rates in different humidity regimes resulted in the differences of static measurements while the differences of dynamic measurements were resulted from the humidity difference between the inner and exterior of the tube in different humidity regimes. PTFE thin film not only kept the high porosity of AAO template but also improved its surface anti-pollution ability.