Thin Film Capacitive Sensors
Thin Film Capacitive Sensors
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薄膜电容传感器
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
A. Paukkunen
中科院分区：
文献类型：
--
作者：
H. Smit;R. Kivi;H. Vömel;A. Paukkunen
微型技术的成就促进了各种各样的非常小的湿度传感器的开发，用于测量气体系统中的水蒸气含量。今天，市场上超过75%的湿度传感器采用电容技术（Rittersma 2002）。这些电容式传感器中的大多数是基于薄膜在水蒸气吸收时的介电变化作为水蒸气含量的量度。多孔聚合物材料充当水活性海绵，由此聚合物材料内的水分子与气相处于热力学平衡，即分子吸附到表面上的速率与分子解吸到气相中的速率正好平衡（安德森1995）。水粘附的特征在于通过水分子与聚合物分子的亲水基团的“弱”货车相互作用形成的物理氢键（例如，Matsuguchi等人，1998）。电容式薄膜湿度传感器响应于周围空气中的相对湿度而不是绝对湿度的变化以及温度的变化。因此，它通常根据相对湿度（RH）进行校准。湿度传感器的响应时间取决于聚合物吸附和解吸水蒸气的能力以及传感器设计，由此它强烈地取决于传感器的温度。传感器对化学污染敏感，这是由于非水分子的额外结合或降低聚合物吸附水分子的能力，这可能导致干偏置或降低传感器的灵敏度。最著名的气象应用是Vaisala（芬兰）在1970年代开发的Humicap传感元件（Salasmaa和Kostamo，1975年），自1980年以来一直用于其无线电探空仪。基于薄膜技术，传感器由水活性聚合物膜组成，作为施加在电极上的两个电极之间的电介质。
Achievements in microtechnology have encouraged the development of a large variety of very small humidity sensors for miscellaneous applications to measure the water vapour content in gaseous systems. Today, more than 75 % of these miniaturised humidity sensors in the market use a capacitive technique (Rittersma 2002). Most of these capacitive sensors are based on dielectric changes of thin films upon water vapour uptake as a measure of the water vapour content. The porous polymer material acts as a hydroactive sponge whereby the water molecules within the polymer material are in thermodynamic equilibrium with the gas phase, i.e. the rate of adsorption of molecules onto the surface is exactly counterbalanced by the rate of desorption of molecules into the gas phase (Anderson 1995). The water adhesion is characterized by physical hydrogen bonds through the “weak” Van der Waals interaction of water molecules with the hydrophilic groups of the polymer molecules (Matsuguchi et al. 1998, e.g.). The capacitive thin-film moisture sensor responds to changes of relative, rather than absolute humidity in the surrounding air as well as to changes of temperature. It is, therefore, commonly calibrated in terms of relative humidity (RH). The response time of the humidity sensor is dependent on the polymer’s ability to adsorb and desorb water vapour and on the sensor design, whereby it is strongly dependent on the temperature of the sensor. The sensor is sensitive to chemical contamination by either additional bonding of the non-water molecules or reducing the ability of the polymer to adsorb water molecules, which may cause either a dry bias or reduce the sensitivity of the sensor. The best known meteorological application is the Humicap sensing element developed by Vaisala (Finland) in 1970’s (Salasmaa and Kostamo1975), which is being used on their radiosondes since 1980. Based on thin-film technology the sensor consists of a hydroactive polymer film as dielectric between two electrodes applied on a
北极、中纬度和热带卷云的冰水含量 - 第 2 部分：数据库扩展和新的统计分析
影响因子：
6.3
作者：
Luebke;L. Avallone;C. Schiller;C. Rolf;M. Krämer
通讯作者：
M. Krämer