聚苯胺-复合钒钼酸纳米复合材料的湿敏特性研究

采用原位氧化聚合法制备了聚苯胺—复合钒钼酸纳米复合材料,并对其进行了XRD表征和湿敏特性研究。结果表明:聚苯胺插入复合钒钼酸层间,当An∶H2V10Mo2O31±y=1/2∶1时,湿敏性能最好,在工作频率为1 kHz,温度为20℃的条件下,PAn-H2V10Mo2O31±y湿敏元件在全湿度范围内线性好、灵敏度高,是一种很有前途的新型湿敏材料。     

新型电子材料—沸石分子筛

介绍了沸石分子筛在化学传感器，纳米组装复合材料，光电材料和器件设计等方面的研究工作，以及超大晶体和超大孔径沸石分子筛合成的进展，这类新电子材料的新效应，新原理和新器件的设计研究将对理论和实践产生重大而深远的影响。     

沸石与CuO复合材料的气敏性能研究

采用水热合成法制备了花状CuO材料.为了改善CuO气体传感器性能,分别将ZSM-5型、HY型以及NaA型沸石与p型半导体CuO材料以涂覆法和直接混合法复合制成气敏元件.用X-射线衍射(XRD)、电子扫描显微镜(SEM)分别对制备的CuO材料以及3种沸石与CuO复合材料的形貌及其微观结构进行了表征与分析.将制备的几类敏感元件对多种VOC气体进行气敏测试.结果表明,与纯CuO相比,ZSM-5沸石/CuO复合材料均显著提高了对甲苯的响应值;HY沸石/CuO复合材料提高了对丙酮、乙醇、甲苯的响应值;NaA沸石/CuO复合材料改善了对乙醇和甲醛气体的响应值.初步分析了ZSM-5、HY、NaA沸石对CuO气敏特性改善的机理.     

铁酸镧与高分子复合材料湿敏元件特性分析

采用纳米铁酸镧与高分子复合材料制成湿敏元件。研究了复合材料和湿敏元件的制作,测试讨论了灵敏度、湿滞、电容特性、阻抗特性、响应 恢复时间等湿度敏感特性。结果表明:元件的灵敏度较高、湿滞较小,元件的电容值和阻抗值随频率与相对湿度而变化。     

氨气检测的聚苯胺碳纳米管复合敏感膜的研究与应用

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。     

基于纳米沸石分子筛薄膜的新型气体传感器

研究了一种基于纳米沸石分子筛Ag+ZSM 5的新型气体传感器。该传感器利用纳米沸石分子筛Ag+ZSM 5对丙酮分子有较好的选择性和石英晶体振荡器对微小质量改变的高度灵敏性的特性设计并制作了对丙酮敏感的气体传感器。研究结果发现,采用ZSM 5型分子筛并用Ag+对该分子筛进行修饰可以提高对丙酮气体的响应,而对乙醇的响应较小。对不同浓度的丙酮气体的测试表明:在较低的丙酮气体浓度(0.67μmol/L)下,传感器表现出良好的响应,检测灵敏度较高,可达到44.8Hz/(μmol·L-1)。同时,该传感器具有良好的可逆性、重复性。     

ZrO2:TiO2复合纳米纤维湿度传感器的直、交流特性研究

利用ZrO2:TiO2复合纳米纤维制作了特性良好的电容型湿度传感器.该湿敏元件在100 Hz测量频率下灵敏度较高,线性度较好.其电容值在11％ ～98％相对湿度范围内从20 pF变化到1.5×105 pF.文中从直流特性(伏安特性、极性反转瞬时性)和交流特性(复阻抗)的角度分析了该湿敏元件的感湿机理.利用瞬时直流极性反...     

以聚苯胺表面包覆钛酸钡作为填料的环氧复合材料的微观结构与介电性能

通过原位聚合的方法合成了表面包覆钛酸钡的聚苯胺复合纳米颗粒(BT@PANI),并将该复合纳米颗粒作为填料制备了具有特殊结构的BT@PANI/EP三相复合材料。实验发现由于导电聚苯胺增强了界面极化,因此随着BT@PANI中PANI质量的增加(即BT在复合材料中的质量分数减少),该复合材料的介电常数也随之增加。当PANI的质量分数从0%增加至26%时,其介电常数也从17提高到了53,并且当BT@PANI中PANI的质量分数达到26%时,该复合材料并没有出现明显的渗流效应,且其导电率保持在1.64×10-6 S/m这一较低值。此外,当测量温度范围在60℃到100℃之间时,该复合材料的介电常数发生了明显的上升,这一现象可以说明随着温度的上升,导电聚苯胺、环氧分子链在Tg温度(90℃)下运动增强及钛酸钡在居里温度(120℃)下的相变共同产生了强烈的界面极化。     

Y沸石改善SnO2气体传感器性能的研究

为了改善气体传感器的敏感性能,分别采用SnO2外涂Y沸石的涂覆法和Y沸石与SnO2混合法,用Y沸石对SnO2气体传感器进行改性.用X-射线衍射(XRD)、电子扫描显微镜(SEM)对混合法制备的Y沸石/SnO2复合材料的结构和表面进行了表征与分析.将这两类敏感元件进行了VOC气体的气敏测试.结果表明,与纯SnO2相比,Y沸石与SnO2直接混合的复合材料提高了对丙酮的响应值,而对其他气体响应值基本不变;涂覆法制备的气敏元件不仅提高对丙酮的响应值,而且减小了对乙醇的响应值,对乙醇起到一定抑制作用.初步分析了Y沸石对SnO2气敏特性改善的机理.     

多孔Al_2O_3薄膜感湿材料的湿敏特性研究

通过对阳极氧化多孔Al2 O3 薄膜感湿材料的制备工艺及其电容湿敏特性进行研究 ,将阳极氧化参数对多孔Al2 O3 薄膜的结构和形态的影响与多孔Al2 O3 薄膜作为湿度传感器感湿材料的湿敏特性联系起来进行分析 ,为优化制备工艺参数提供更充分的实验数据 ,使新型多孔Al2 O3 薄膜湿度传感器具有更好的感湿特性。     

电化学法合成氧化锌/聚苯胺复合多孔薄膜的湿敏传感特性

为设计出一种适用于矿井内部的湿度传感器,采用电化学分步恒电流法,制备出多孔结构的聚苯胺薄膜,并将氧化锌颗粒负载于聚苯胺薄膜表面,获得一种无机/有机复合p-n异质结传感材料。并使用62.8%、72.5%、76.2%和86.8%四种湿度对传感器进行传感性能测试。结果表明当电流密度为19.2 mA/cm^2时,聚苯胺薄膜表面负载的氧化锌质量为5.85×10^-3 g,传感器的电化学活性面积(ESA)最大为268.5 m^2/g,传感器灵敏度达到峰值0.66。同时对传感器的传感机理进行了讨论。     

分子筛自控系统原理

介绍分子筛的主要用途,阐述分子筛自动控制原理及故障形成原理.     

Study on humidity sensing property based on Li-doped mesoporous silica MCM-41

Pure and LiCl-doped mesoporous silica MCM-41 with different doping concentrations (1, 2, 5, 10 and 15 wt.%) have been prepared. XRD, IR spectra and SEM characterized the materials. These different characterization results suggest that these materials have the similar mesoporous structure. A resistive-type humidity sensor was fabricated on a ceramic substrate with Ag–Pd interdigital electrodes. The humidity sensing properties of the sensors were investigated at different frequencies. The studies revealed that the LiCl-doping was beneficial for improving the humidity sensing properties of the samples. The sample with 2 wt.% LiCl dopant has the best sensing properties to humidity. Finally, a possible mechanism is suggested to explain the humidity-sensitive properties.     

基于分子筛薄膜探测神经类毒气的传感器研究

采用ZSM-5分子筛材料对神经类毒剂沙林的相似物甲基磷酸二甲脂(DMMP)气体进行了测试。分子筛材料因为具有选择性吸附分子的能力常被用来作为气体敏感材料,但因为其神经类气体极性较强,被吸附后难于解吸附,因此,分子筛材料很少用于检测神经类气体。利用合成的ZSM-5纳米分子筛作为吸附神经类气体DMMP的敏感材料,将其涂布在2个石英晶体微天平(QCM)上进行差频测试,以减小外界的干扰,并提出了用交变电场进行极性分子解吸附的新方法。DMMP气体的探测最小体积分数达到1×10-6,响应时间和解吸附时间分别小于20 s和90 s。     

Nanostructured polyaniline thin films as pH sensing membranes in FET-based devices

Polyaniline (PANI) has become an important conducting polymer for sensing due to its morphological and electrical properties. However, the processing of polyaniline in the form of nanostructured thin films is often limited by the low solubility of the polymer in water. We synthesized nanostructured polyaniline (N-PANI) aimed at improving its solubility to form layer-by-layer (LbL) thin films in conjunction with poly(vinyl sulfonic acid) (PVS) as counter ion. N-PANI was characterized via spectroscopic measurements and SEM images. After assembled as LbL thin films onto gold (Au) substrates, the PVS/N-PANI were employed as separative extended gate pH sensing membrane in FET-based devices presenting pH sensitivity around 58 mV/pH with small voltage drift. The results suggest that N-PANI can be easily processed to form suitable thin films for pH sensing and can be combined with biomolecules to be applied in FET-based biosensors.     

Zeolite-coated interdigital capacitors for humidity sensing

Inter-digital capacitors (IDCs) with electrode gaps of 10 or 50 microns have been coated with zeolite films consisting of different zeolites with Si/Al ratios ranging from 1.5 (zeolite A) to infinite (silicalite). The performance of the sensor in the measurement of humidity has been related to the electrical properties of the zeolites (relative permittivity, ?_r), which in turn is a function of their Si/Al ratio. With zeolites of a high Al content the limit of detection was under 0.5 ppmV.     

以聚苯胺与无机盐复合物为载体的离子选择电极

有机-无机杂化材料因具有二者的优势在新型敏感材料领域引起了人们的广泛关注.根据近期研究工作和国外最新文献,系统论述了聚苯胺-无机盐复合物的离子选择交换与络合能力,重点评述了由聚苯胺-无机盐复合物作活性载体制成的离子选择膜电极的特性.指出聚苯胺-磷酸锡、聚苯胺-磷酸砷锡、聚苯胺-钨酸砷锡复合物分别对He2 、Pb2 和Cd2 具有较好的交换与络合能力,在其它离子共存时,对上述三种离子的选择系数均远远大于1.将该复合物作为活性载体制作的离子选择电极对重金属离子如Hg2 、Cd2 具有很高的灵敏度,能斯特斜率与理论值29.6 mV/decade相近.响应时间均不超过40 s,探测下限可低至10-6 mol/L,且线性范围较宽,共存离子基本无干扰.     

Electrical and humidity sensing properties of carbon nanotubes-SiO2-poly(2-acrylamido-2-methylpropane sulfonate) composite material

Alkali salts of poly(2-acrylamido-2-methylpropane sulfonate) (PAMPS)-SiO₂ and single-walled carbon nanotubes (SWCNTs)-SiO₂-PAMPS were used as composite materials to make a humidity sensor. The impedances of these composite materials were measured at various humidities and temperatures in the frequency range of 1–100 kHz. The results indicated that the H⁺ form of the PAMPS-SiO₂ composite film had the highest electrical conductance. For practical use, a humidity sensor, which was a low-resistance device, commonly required for electronic circuit compatibility, was prepared from SWCNTs-SiO₂-PAMPS composites. The sensing mechanism of the SWCNTs-SiO₂-PAMPS composite films were explained by considering the observed impedance plot and activation energy compared with a SiO₂-PAMPS composite film. At low relative humidity (RH), new conductive paths were formed, whereas with increasing RH, the ionic contribution became prevalent. Other sensing properties of the SWCNTs-SiO₂-PAMPS composite films such as effects of applied frequency, ambient temperature and hysteresis were also investigated.