高分子湿敏电容的设计

从传感器功能要求出发,阐述了高分子湿敏电容正向设计规则.介绍了电容型高分子湿敏元件的感湿机理、元件结构、工艺过程和感湿材料设计方法,同时以应用示例给予说明.     

湿度传感器用湿敏材料

本文综述湿度传感器中使用的各种湿敏材料。按有机湿敏材料和无机湿敏材料两类叙述。重点介绍研究最多的高分子电解质材料和陶瓷材料.     

高分子湿敏材料

综述了高分子湿敏材料的现状及其发展，着重分析了3种类型的高分子湿敏材料(带有强极性基团、弱极性基团以及加入导电粉末的高分子材料)的感湿机理，提出了根据不同的感湿机理将材料应用于不同类型的湿度传感器，并根据高分子材料的感湿机理，对湿度传感器用高分子材料的发展进行了预测。     

电极结构对高分子电阻型湿度传感器性能的影响

本文以聚苯乙烯磺酸钠为湿敏材料,制备了以金叉指电极为基底的高分子电阻型湿度传感器。研究了电极基片材料和叉指电极构型对传感器湿敏响应特性的影响。研究表明,采用多孔结构的基片材料可降低传感器电阻,增强湿敏膜与基片的结合能力从而提高传感器的稳定性;叉指电极构型对传感器的电阻大小有一定影响,增加电极中心线间距离使传感器的稳定性提高。     

高分子电阻型湿敏元件的复阻抗谱测试与分析

测量了高分子电阻型湿敏元件在低湿和高湿的复阻抗谱,利用复阻抗谱法求出了湿敏元件的体电阻,由此分析了湿敏元件的导电机理。     

高分子敏感材料及其应用

高分子敏感材料是一种新兴的电子材料,这种材料具有半导体、导电、光电、介电及绝缘等多种功能。充分利用它的各种功能效应,可以进一步充实和扩展敏感元件的应用领域。利用高分子敏感材料可以制作湿敏、压敏、力敏、热敏、声敏、气敏、光敏、离子敏、生物敏等各种敏感元件。这种材料的主要特点是质轻、透明、柔软、易加工、成本低廉等。高分子敏     

高分子材料在化学敏感元件中的应用

化学敏感元件是测定化学物质的敏感元件,近年来,发展很快。在化学敏感元件的发展过程中,由于高分子材料具有其自身的优良特性,例如,具有从绝缘体到导体的宽广的电特性;成形性好,容易加工成膜状、纤维状;对液体、气体的透过性好;容易和其它材料复合制成复合材料等,高分子材料起着重要作用。高分子材料已在化学敏感元件中获得广泛应用.本文将介绍高分子材料在气敏元件、湿敏元件、离子敏元件以及生物敏元件方面的应用.     

高分子电阻型湿敏材料的老化机理

本文以聚苯乙烯磺酸钠为湿敏材料制备了高分子电阻型湿度传感器,研究了其在高温高湿环境下,施加交流电激励后的老化行为。考察了通电电压、通电时间等对传感器响应特性的影响,并对其老化机理进行了探讨。提出通电老化后,湿敏材料在不同湿度下的电阻变化决定于高温高湿环境造成的溶解效应和施加电压后引起的通道效应和离子破坏效应。研究表明,在较高湿度环境下(87~93%RH),施加800mv的电压可加速湿敏材料的老化过程,使湿度传感器响应信号较快达到稳定,从而有望改善湿度传感器的稳定性。     

纳米与高分子复合湿敏材料性能分析

将两种湿敏材科纳米BaiTiO3与高分子(R)nM+X-混合制成复合湿敏材料.分析讨论了复合材料的IR,XPS谱图,并与BaTiO3谱图作了比较.     

国内外高分子电容式湿敏材料研究现状

综述了近年来国内外发展迅速的高分子电容式湿敏材料的研究状况,并对其今后的研究方向作了分析与展望.     

Simultaneous measurement of humidity and temperature by combining a reflective intensity-based optical fiber sensor and a fiber Bragg grating

A novel sensor capable of simultaneously measuring temperature and humidity has been fabricated and demonstrated using optical fiber waveguides. The sensor head is composed of a fiber Bragg grating and a low-finesse Fabry-Perot interferometric cavity. The Fabry-Perot cavity was fabricated using the electrostatic self-assembled monolayer process for the molecular-level deposition of materials of different thicknesses that form a humidity-sensitive coating on the end of the fiber, while the in-line Bragg grating fiber element is used to monitor temperature. Experimental results for a humidity range from 11% to 97% RH and for a temperature range from 10/spl deg/C to 85/spl deg/C are shown.     

烧结工艺对SnO2-LiZnVO4系纳米湿敏材料性能的影响

采用共沉淀法制备出SnO2-LiZnVO4系纳米粉体,考察了烧结工艺对材料微结构、湿敏特性和电容特性的影响。实验结果表明,适当的烧结工艺可明显改善纳米材料的微结构和感湿特性,采用共沉淀法制备SnO2-LiZnVO4系纳米粉体并选择好烧结温度,可使材料具有棒状晶粒微结构及低湿电阻小、灵敏度适中的湿敏试样。     

Effect of V2O5 on the electrical properties of TiO2-V2O5 humidity sensors

TiO₂-V₂O₅ ceramic humidity sensors were prepared and measured to obtain the relationships between the added amount of V₂O₅ and the properties of the sensor elements, such as total pore volume, bulk impedance and the humidity-sensitive property in the low relative humidity region. It was observed that both the microstructure and the bulk impedance of the sensor element were strongly dependent on the added amount of V₂O₅. The equivalent circuit of the specimen was postulated for analysis and the sensor characteristics in low and high humidity regions are discussed. The samples which contained higher amounts of V₂O₅ seemed to be more strongly hygroscopic in low humidities, whereas the samples that had higher pore volumes contained water much more at high humidities.     

A surface acoustic wave humidity sensor with high sensitivity based on electrospun MWCNT/Nafion nanofiber films

Humidity detection has been widely used in a variety of fields. A humidity sensor with high sensitivity is reported in this paper. A surface acoustic wave resonator (SAWR) with high resonance frequency was fabricated as a basic sensitive component. Various nanotechnologies were used to improve the sensor's performance. A multi-walled carbon nanotube/Nafion (MWCNT/Nafion) composite material was prepared as humidity-sensitive films, deposited on the surface of an SAWR by the electrospinning method. The electrospun MWCNT/Nafion nanofiber films showed a three-dimensional (3D) porous structure, which was profitable for improving the sensor's performance. The new nano-water-channel model of Nafion was also applied in the humidity sensing process. Compared to other research, the present sensor showed excellent sensitivity (above 400 kHz/% relative humidity (RH) in the range from 10% RH to 80% RH), good linearity (R(2) > 0.98) and a short response time (～3 s@63%).     

SnO2-K2O-LiZnVO4系材料湿敏性能及导电机理的研究

采用共沉淀法制备出SnO2-K2O-LiZnVO4系湿敏粉体,考察了液相掺杂K 对材料湿敏特性的影响,并用直流特性法对材料的导电机理进行了分析.实验结果表明,适当的K 液相掺杂可使材料具有低湿电阻小,灵敏度适中的特性.直流特性法分析表明,材料属电子-离子混合导电机制,且离子电导成分越多材料的湿敏特性越好.     

Use of polymeric indicator for electrochemical DNA sensors: poly(4-vinylpyridine) derivative bearing [Os(5,6-dimethyl-1,10-phenanthroline)2Cl]2+

A poly(4-vinylpyridine) (PVP) derivative bearing redox-active osmium complexes, PVP-[Os(5,6-dmphen)(2)Cl](2+) (5,6-dmphen = 5,6-dimethyl-1,10-phenanthroline), was employed as a hybridization indicator for electrochemical DNA sensors. PVP-[Os(5,6-dmphen)(2)Cl](2+) exhibited approximately 1000 times higher sensitivity than the corresponding monomeric analogue, [Os(5,6-dmphen)(3)](2+), in DNA determination due to polymeric effects. The detection limit of the present sensor was approximately 0.5 amol. Another merit of the polymeric indicator is that the redox potential was found to be +360 mV (vs Ag/AgCl), which is significantly lower than that reported for the monomeric analogue (+672 mV). The polymeric indicator was applicable to the discrimination of single- and double-base-mismatched DNAs from fully matched target DNA. The polymeric indicator can be removed from the electrode surface by rinsing the electrode in a high-temperature buffer for 6 min, and thus, the polymeric indicator-based DNA sensor can be used repeatedly.     

Fabrication of a planar polymeric deformation Bragg sensor component by excimer laser radiation

Polymethylmethacrylate is irradiated by a UV-laser in order to modify its optical properties photochemically. Thus, by a lithographic method, the refractive index can be locally increased in a controllable way permitting the manufacturing of integrated-optical waveguiding and dispersive structures at the surface of a planar polymer chip. By this method, a polymeric Bragg sensor in integrated-optical form was fabricated by the UV-light of an excimer laser. The surface topography and the functional properties of the planar polymeric deformation Bragg sensor have been examined. Experiments concerning the evanescent field of the sensor have also been carried out in order to clarify the Bragg reflection mechanism.     

Integrated potentiometric detector for use in chip-based flow cells

A new kind of potentiometric chip sensor for ion-selective electrodes (ISE) based on a solvent polymeric membrane is described. The chip sensor is designed to trap the organic cocktail inside the chip and to permit sample solution to flow past the membrane. The design allows the sensor to overcome technical problems of ruggedness and would therefore be ideal for industrial processes. The sensor performance for a Ba2+-ISE membrane based on a Vogtle ionophore showed electrochemical behavior similar to that observed in conventional electrodes and microelectrode arrangements.     

ZnCr2O4-V2O5-Li2O-ZnO湿敏材料的气体选择性研究

测试了ZnCr2O4-V2O5-Li2O-ZnO感湿体在H2、CO2、煤气、酒精蒸汽等气体环境中电阻的变化情况.结果表明,电阻值明显随环境温度变化但基本不受气体影响.     

Micro-array versus nano-array platforms: a comparative study for ODN detection based on SPR enhanced ellipsometry

The rapid and sensitive detection of DNA has recently attracted worldwide attention for a variety of disease diagnoses and detection of harmful bacteria in food and drink. In this paper, we carried out a comparative study based on surface plasmon resonance enhanced ellipsometry (SPREE) for the detection of oligodeoxynucleotides (ODNs) using micro- and nano-array platforms. The micro-arrayed surfaces were fabricated by a photolithography approach using different types of mask having varying size and shape. Well-ordered arrays of high aspect ratio polymeric nanotubes were also obtained using high molecular weight polystyrene (PS) and anodic aluminum oxide (AAO) membranes having 200 nm pore diameters. The SPREE sensors were then prepared by direct coupling of thiolated probe-ODNs, which contain suitable spacer arms, on gold-coated micro- and nano-arrayed surfaces. We experimentally demonstrated that, for the first time, gold-coated free standing polymeric nano-arrayed platforms can easily be produced and lead to a significant sensor sensitivity gain compared to that of the conventional SPREE surfaces of about four times. We believe that such an enhancement in sensor response could be useful for next generation sensor systems.