【作者】 李勇；

【导师】 黄见秋；

【作者基本信息】 东南大学 ， 微电子学与固体电子学， 2022， 硕士

【摘要】 湿度不仅是气象监测中的一个重要参数,在农业种植、工业控制和医疗领域等方面也发挥着重要作用。近些年,随着可穿戴电子设备、电子皮肤、柔性显示等概念的兴起,越来越多的研究人员开始关注柔性湿度传感器。常见的柔性衬底有聚酰亚胺(PI)、聚对苯二甲酸乙二醇酯(PET)、聚二甲基硅氧烷(PDMS)等,和这些材料相比,疏水聚四氟乙烯(PTFE)微孔材料具有化学性质稳定、耐高低温、机械性能优良等特点,并且它的疏水特性和微孔结构使其表现出极佳的透气性,因此更适合作为柔性湿度传感器的衬底材料。此外,湿度传感器面临多种复杂的应用环境,而有线湿度传感器往往不适用于恶劣环境、密闭空间以及旋转条件等,因此需要开发环境适应性更好的无源无线湿度传感器,本文设计并制备了一种以疏水聚四氟乙烯微孔材料为衬底的LC无源无线湿度传感器。主要工作如下:(1)提出了一种基于疏水聚四氟乙烯微孔衬底的湿敏电容,湿敏材料是氧化石墨烯(GO)。介绍了湿敏电容的结构和制备工艺,测试了湿敏电容的静态和动态特性,结果表明在30%RH～90%RH的范围内,湿敏电容的灵敏度为20.68 f F/%RH,最大回滞为2.51%RH,响应时间为10秒,恢复时间为3秒,并验证了疏水聚四氟乙烯微孔衬底的背面感湿特性。(2)为了解决氧化石墨烯在高湿条件下的漏电损耗问题,在叉指电极和氧化石墨烯之间通过静电纺丝工艺制备了网状聚偏氟乙烯/聚四氟乙烯(PVDF/PTFE)隔离层,研究了纺丝溶液用量、聚四氟乙烯掺入量以及静电纺丝速度三个因素对湿敏电容性能的影响。(3)在湿敏电容的基础上,设计并制备了基于疏水聚四氟乙烯微孔衬底的LC无源无线湿度传感器。测试了传感器的静态和动态特性,结果表明在30%RH～75%RH的范围内,传感器的灵敏度为11.689 k Hz/%RH,最大回滞为3.25%RH,响应时间为4秒,恢复时间为2秒,但是传感器在90%RH条件下谐振频率难以分辨。通过增加静电纺丝隔离层,传感器在高湿下的品质因数有了明显的改善,提高了传感器的湿度检测范围。更多还原

【Abstract】 Humidity is important not only for meteorological monitoring,but also for agricultural planting,industrial control and medical fields.In recent years,with the rise of concepts such as wearable electronic devices,electronic skin and flexible display,more and more researchers have paid attention to flexible humidity sensors.Commonly,the substrate materials of flexible humidity sensors include polyimide(PI),polyimide Ethylene phthalate(PET),polydimethylsiloxane(PDMS)and so on.Compared with these materials,the hydrophobic microporous polytetrafluoroethylene(PTFE)has the advantages of stable chemical properties,good thermal stability and excellent mechanical properties.Moreover,hydrophobic characteristic and microporous structures make it breathable.So it has the potential to be an excellent substrate of flexible humidity sensors.In addition,humidity sensors face a variety of complex application environments,while wired humidity sensors can not be used in harsh environments,sealed spaces rotation conditions and so on.In these cases,passive wireless humidity sensors should be applied.In this paper,an LC passive wireless humidity sensor based on hydrophobic PTFE microporous material is designed and fabricated.The main work is as follows:(1)Based on a hydrophobic PTFE microporous substrate,a humidity sensitive capacitor with GO as the sensitive material is proposed.The structure and fabrication processes are developed.Both static and dynamic performances of the humidity sensitive capacitor are tested.The results show a sensitivity of 20.68 f F/%RH and a maximum hysteresis of 2.51%RH over the range of30%RH～90%RH.The response time and recovery time are 10 s and 3 s,respectively.Also,the breathable property of the substrate is verified.(2)In order to reduce the dielectric loss of GO at high humidity,a polyvinylidene fluoride/polytetrafluoroethylene(PVDF/PTFE)isolation layer with network structure is fabricated between the interdigitated electrode and GO sensitive layer by an electrospinning process.Effects of solution dosage,PTFE concentration and electrospinning speed on the performance of humidity sensitive capacitors are studied.(3)Based on the humidity sensitive capacitor,an LC passive wireless humidity sensor fabricated on the hydrophobic PTFE microporous substrate is designed and manufactured.The static and dynamic characteristics of the sensor are tested.The results show that,in the range of30%RH～75%RH,the sensitivity of the sensor is 11.689 k Hz/%RH and the maximum hysteresis is3.25%RH.The response time and recovery time are 4 s and 2 s,respectively.But the resonant frequency of the sensor is indistinguishable at 90%RH.With electrospun isolation layer,the quality factor of the sensor is improved,especially at high humidity,which increases the humidity detection range of the sensor.更多还原