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本文介绍了基于聚苯胺及多壁碳纳米管复合材料的氨气传感器的制备与测试,使用原位聚合法使苯胺单体以碳纳米管为核心进行聚合反应,运用介电泳法制备得聚苯胺/多壁碳纳米管气敏复合膜传感器。该传感器对10×10-6氨气的响应灵敏度为3.4,响应时间15 s,而对比实验中聚苯胺膜传感器的灵敏度为1.9。实验结果表明,由于碳纳米管在介电泳过程中构建的大比表面积纳米三维结构和优良的导电率,纳米复合材料的微观结构和导电性能都得到大幅改善,从而使得复合物具有相对于纯聚苯胺膜更好的气敏特性。 相似文献
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碳纳米管掺杂WO_3气敏元件敏感特性的研究 总被引:5,自引:0,他引:5
研究以碳纳米管(CNT)为掺杂剂制备的CNT-WO3旁热式气敏元件。采用球磨、超声分散的方法对碳纳米管进行分散处理,溶胶—凝胶方法制备WO3微粉,用SEM观察了WO3气敏材料的显微结构,测试了元件对丙酮的气敏性能。结果表明:碳纳米管存在于平均粒径为30~50 nm的WO3晶粒间,从而增加了材料的气孔率。碳纳米管掺杂元件对丙酮的灵敏度远高于纯WO3元件,质量分数为0.4%的掺杂量对丙酮有最高灵敏度,具有能检测低体积分数丙酮气体、选择性好的优点,特别是掺杂碳纳米管明显提高了WO3元件的响应速度。 相似文献
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为了研究并提升氧化钯(PdO)敏感电极的气敏性能,采用Ni,La和Mg元素对PdO进行掺杂.通过掺杂前后PdO的表征实验对比,发现掺杂作用不仅改变晶格参数,同时也影响晶体中的缺陷.在对丙烯气敏测试中,Ni和La掺杂的PdO敏感电极提高了传感器气敏灵敏度.对于掺杂提高气敏响应的机理,我们根据不同元素掺杂对PdO气敏反应的不同作用,讨论了氧化物缺陷对PdO催化活性的影响.晶体中的氧缺陷可以提高氧化物的催化活性,使传感器具有较高的灵敏度.具有掺杂PdO敏感电极对氧气和多种气体的选择性测试,表现出对丙烯气体具有较高的选择性. 相似文献
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采用酸化后的碳纳米管与聚苯胺掺杂作为传感器的气敏材料.通过丝网印刷技术将无铅铝浆印刷在氧化铝陶瓷基板上形成电感线圈,并将制备好的气敏材料涂覆到电感线圈上,制备出LC谐振式无源气体传感器.制作成气体传感器后在NH3气氛中进行测试分析,实现了在密闭环境下的非接触测量.重点分析了在室温下NH3气体的浓度对传感器谐振频率f0的变化及响应恢复时间的影响,结果表明气体浓度在300×10-6时,传感器的灵敏度为4.499 MHz. 相似文献
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Nicholas J. PintoAuthor Vitae Danairé RiveraAuthor VitaeAnamaris MelendezAuthor Vitae Idalia RamosAuthor VitaeJong Hsien LimAuthor Vitae A.T. Charlie JohnsonAuthor Vitae 《Sensors and actuators. B, Chemical》2011,156(2):849-853
Electrospun isolated nanofibers of poly(3,4-ethylenedioxythiophene) doped with (poly styrene sulfonic acid)-PEDOT-PSSA were used to sense vapors of several aliphatic alcohols. Due to the large surface to volume ratio and small quantity of active material used in their fabrication, these sensors have a similar or faster response time when compared to alcohol sensors based on PEDOT. Increasing the size of the alcohol molecule leads to longer response times, which is attributed to slower diffusion of the larger molecule into the polymer. The sensors were annealed in air at 70 °C and used to sense NH3, HCl and NO2 gas. The response time for NH3 was faster than HCl, and the sensors showed a large initial response to NO2 at room temperature which is very desirable, as some NO2 gas sensors only operate at elevated temperatures. Electrospinning is a simple and inexpensive method of preparing PEDOT-PSSA nanofibers making it an attractive technique to fabricate polymer based low cost, rapid response and reusable gas sensors. 相似文献
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采用酸氧化法对多壁碳纳米管(MWCNTs)进行表面修饰,并研究了基于MWCNTs/羟乙基纤维素(HEC)复合体系的结露传感特性。通过红外光谱和热失重分析对MWCNTs进行了结构表征。氧化处理有效提高了MWCNTs的分散性。基于改性MWCNTs的结露元件与本征MWCNTs的器件相比表现出更好的开关特性。结露元件在相对湿度(RH)为75 %RH以前伴随湿度变化,电阻变化非常小,而在85 %RH以后呈现电阻的非线性增大。MWCNTs在复合膜中的最佳质量分数约为22 wt%,在100 %RH下灵敏度达到31。 相似文献
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Jean-Marc TullianiAuthor Vitae Alessio CavalieriAuthor VitaeSimone MussoAuthor Vitae Eloisa SardellaAuthor VitaeFrancesco GeobaldoAuthor Vitae 《Sensors and actuators. B, Chemical》2011,152(2):144-154
In this work, different techniques are proposed to realize ammonia (NH3) sensors working at room temperature and a preliminary electrical characterization under water vapor and in NH3 atmospheres is presented. Three families of ceramic planar sensors based on a zinc oxide (ZnO) layer overlapped by screen-printed Pd-doped carboxyl groups functionalized multi-walled carbon nanotubes (Pd-COOH-MWCNTs) or by blocks of vertically aligned MWCNTs or by graphite as such and functionalized with fluorinated or nitrogenous functional groups were studied.These sensors were almost insensitive to humidity, while all of them gave a good response in NH3 atmosphere, starting from about 45 ppm in the case of zinc oxide with fluorinated or nitrogenous MWCNTs and graphite or 50 ppm for Pd-COOH-MWCNTs sensors. These results are not actually as good as those reported in the literature, but this preliminary work proposes simpler and cheaper processes to realize NH3 sensor for room temperature applications. 相似文献
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以多壁纳米碳管(MWCNTs)为电子媒介体和酶的吸附载体,利用层层累积的自组装技术固定葡萄糖氧化酶(GOx)的多层(MWCNTs/GOx)n复合薄膜修饰电极,制备了一种新型葡萄糖生物传感器。结果表明:传感器对葡萄糖的响应电流值随着MWCNTs/GOx复合薄膜层数的不同而变化,当MWCNTs/GOx复合薄膜的层数为6时,响应电流值达到最大。(MWCNTs/GOx)6复合薄膜修饰的葡萄糖生物传感器对3×10-2mol/L葡萄糖的响应电流为1.63μA,响应时间仅为6.7 s。该生物传感器检测的线性范围为5×10-4~1.5×10-2mol/L,最低检测浓度可达0.9×10-4mol/L。 相似文献
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Detection of low concentrations of petroleum gas was achieved using transparent conducting SnO2 thin films doped with 0–4 wt.% caesium (Cs), deposited by spray pyrolysis technique. The electrical resistance change of the films was evaluated in the presence of LPG upon doping with different concentrations of Cs at different working temperatures in the range 250–400 °C. The investigations showed that the tin oxide thin film doped with 2% Cs with a mean grain size of 18 nm at a deposition temperature of 325 °C showed the maximum sensor response (93.4%). At a deposition temperature of 285 °C, the film doped with 3% Cs with a mean grain size of 20 nm showed a high response of 90.0% consistently. The structural properties of Cs-doped SnO2 were studied by means of X-ray diffraction (XRD); the preferential orientation of the thin films was found to be along the (3 0 1) directions. The crystallite sizes of the films determined from XRD are found to vary between 15 and 60 nm. The electrical investigations revealed that Cs-doped SnO2 thin film conductivity in a petroleum gas ambience and subsequently the sensor response depended on the dopant concentration and the deposition temperature of the film. The sensors showed a rapid response at an operating temperature of 345 °C. The long-term stability of the sensors is also reported. 相似文献
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《Sensors and actuators. B, Chemical》2006,113(1):241-248
Active layers consisting of rf sputtered WO3 were deposited on microhotplate substrates. The films were doped with seven different materials (Pt, Au, Ag, Ti, SnO2, ZnO and ITO (indium tin oxide)). The eight types of sensors (including pure tungsten oxide ones) were tested in the presence of ammonia, hydrogen sulphide, nitrogen dioxide, carbon monoxide and methane. It was found that gold improved the sensitivity to H2S. On the other hand, doping with Ag and Pt led to higher responses to NO2 and NH3, respectively. No response to CH4 was observed. The sensitivity to CO was very low. The influence of the working temperature on the sensor response was also studied. Our study proves that selective gas detection is possible combining a few tungsten oxide sensors with different dopants. 相似文献
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D. ZilliAuthor VitaeP.R. BonelliAuthor Vitae A.L. CukiermanAuthor Vitae 《Sensors and actuators. B, Chemical》2011,157(1):169-176
Multi-walled carbon nanotubes (MWCNTs) are successfully processed in the form of thin films (buckypapers), and their morphology and electrical behaviour are characterized. The MWCNTs are synthesized by the floating catalyst chemical vapour deposition process. The effects of a sequence of treatments applied for MWCNTs purification on the buckypapers electrical behaviour are also examined. Nanocomposite thin films constituted of pristine and purified MWCNTs and Pd nanoparticles are prepared in order to evaluate their viability as H2 sensors at room temperature. For this purpose, the electrical resistance of the nanocomposite films in atmospheres with different H2 concentrations, is determined. Scanning electron microscopy (SEM) images show that the buckypapers and the nanocomposite films are 2D structures constituted by randomly oriented MWCNTs. The buckypapers present a semiconductor-like electrical behaviour as determined by the standard four point method. Room temperature resistivity values of around 10−3 Ω m are assessed. Nanocomposite films show different electrical behaviour depending on the purification treatment applied to the MWCNTs employed. Furthermore, the electrical resistance of the nanocomposite films is found to increase when the measurements are performed in H2 atmosphere. Values of H2 sensitivity at room temperature of the nanocomposite films up to 2.15% are determined for H2 average concentration higher than 350 ppm with short recovery time. 相似文献
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Chemically synthesized processable poly (m-aminophenol) (PmAP) film was cast from dimethyl sulfoxide solution and doped with sulfuric acid by solution doping technique. This sulfuric acid doped PmAP film shows a good electrical conductivity. The response of doped film under continuous flow of various aliphatic alcohols vapor and air mixture was examined at room temperature (30 °C) and humidity (65% RH). The doped polymer only showed good result for methanol and ethanol vapor and some week response for the isopropanol vapor. A decrease in resistivity of the doped PmAP film was separately observed in air–alcohol vapor at different concentrations. The response of the film increases as the concentration of the alcohol vapor increases in air–alcohols vapor mixture. The kinetics of the response with respect to the alcohol concentration was studied for methanol and ethanol. Sulfuric acid doped and methanol vapor absorbed doped films were characterized by ultraviolet–visible spectroscopic, attenuated total reflectance Fourier transformed infrared spectroscopic and X-ray diffraction analyses. The mechanism of alcohol vapor sensing by sulfuric acid doped PmAP film has been explained on the basis of the above characterizations. All the above facts are trying to explain from the proposed mechanistic point of view. 相似文献
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Junya Suehiro Naoki Ikeda Akio Ohtsubo Kiminobu Imasaka 《Microfluidics and nanofluidics》2008,5(6):741-747
The authors have previously demonstrated the manipulation of bacteria and carbon nanotubes (CNTs) using dielectrophoresis
(DEP) and its application for various types of biological and chemical sensors. This paper demonstrates simultaneous DEP handling
of bacteria and CNTs, which are mixed and suspended in water. The CNTs were solubilized in water using microplasma-based treatment.
When a microelectrode was energized with an ac voltage in the suspension of Escherichia coli (E. coli) cells and multi-walled CNTs (MWCNTs), both of them were simultaneously trapped in the microelectrode gap. Scanning electron
microscopy (SEM) images revealed that E. coli cells were trapped on the surface or the tip of MWCNTs, where the electric field strength was intensified due to high aspect
ratio of MWCNTs. As a result, bio/nano interfaces between bacteria and MWCNTs were automatically formed in a self-assembly
manner. A potential application of the DEP-fabricated bio/nano interfaces is a drug delivery system (DDS), which is realized
by transporting drug molecules from CNTs to cells across the cell membrane, which can be electroporated by the local high
electric field formed on the CNT surface. 相似文献