基于聚合物-碳黑敏感膜的气体微传感器阵列研究

研究了一种使用聚合物-碳黑混合物作为敏感膜的新型化学气体传感器。通过将4种不同的聚合物敏感材料聚-4-乙烯基苯酚、聚环氧乙烷、聚已内酯和乙烯-醋酸乙烯酯共聚物与一定配比的碳黑混合物分别淀积在梳状微电极上,就可以获得这4种聚合物-碳黑化学电阻型气体微传感器阵列。用这4种传感器对4种气体体积分数为5×10-4的有机类气体(丙酮、乙醇、甲醇和甲苯)进行了测试,比较了传感器的电阻变化率。微传感器的响应值,即电阻的变化率最大接近1.9%;最小的优于0.01%。梳状微电极的形状适合低体积分数的探测。通过对4种传感器响应的主成分分析,可以完全分辨被检测的4种有机类气体。     

基于聚合物碳黑混合物气敏微传感器的研究

通过四种不同的聚合物敏感材料以及混合的碳黑修饰在梳状微电极上,可以得到这种新型的化学气敏电阻型微传感器,将这四种不同聚合物的微传感器分别对丙酮、乙醇、甲醇、甲苯四种有机类气体进行了测试,比较其电阻的相对变化率,利用其响应的主元分析可以将四种气体区分开,并且在一定范围内,电阻的相对变化率可呈一定的线性分布.     

超薄金属修饰石墨烯基气体传感器性能研究

为了改善本征石墨烯基电阻型气体传感器的室温气体响应性能,采用电子束蒸镀方法在原器件沟道区域分别沉积六种超薄金属,包括1 nm的Au、Ag、Pt、Pd、Ti和Al,并检测这些器件对NO_2和NH_3气体的响应特性。发现修饰有1 nm Pt的器件对通入3 min 3×10^-6 NO_2气体有最高的响应灵敏度,达-56.6%,比原石墨烯器件提高了约9.3倍,但该器件响应饱和较早。而修饰有1 nm Ti的器件对NO_2气体的响应在灵敏度、恢复性等方面都有较好改善,且对NO_2气体浓度有最佳的线性响应,表现出较大的动态探测范围。然而除1 nm Ti以外,修饰有其他五种金属的石墨烯对400×10^-6 NH_3的响应均没有明显改善。文章对不同金属材料修饰导致器件气体敏感性能差异的原因进行了分析与讨论。     

丙酮气体传感器的PANI/Au/Al2O3电极制备工艺优化

以微制程技术及电化学法制备PANI/Au/Al2O3电极,并组装成电阻式丙酮气体传感器.以恒电流法在不同电流密度下进行三阶段聚合,并利用混合物实验设计法对纳米结构PANI/Au/Al2O3电极的最佳制备工艺条件进行了优化.结果表明:分别固定聚合电流密度为40,60,80μA/cm2进行三阶段聚合,当聚合电流密度按由小到大顺序,所得的PANI/Au/Al2O3电极稳定性最好.固定聚合电量为35 mC,当三阶段电量比为0.35∶0.33∶0.32时,对于9958 ×10-6丙酮得到最大的感测电阻变化率为7.55％.丙酮气体浓度在(475～1 189) ×10-6与(23-118)×10-6范围内,对应灵敏度分别为1.2×10-3和6.4×10-3％/10-6,平均响应时间为3min.     

基于纳米MnO2的免标记型的电化学适体传感器用于腺苷的测定

以纳米MnO2作为适体固定的构建平台,制备了一种用于腺苷灵敏测定的电化学交流阻抗型生物传感器.[Fe(CN)6]3-/4-作为氧化还原探针监测传感器表面电子传递电阻的变化,表面电子传递电阻的变化值与腺苷的浓度在1.0×10-9～1.0×10-7mol/L范围内有很好的线性关系,最低检测限为8.0×10-10 mol/L.传感器显示出高的灵敏度、好的选择性和稳定性.     

基于石墨烯修饰玻碳电极伏安法测定6-苄氨基嘌呤

该文利用石墨烯修饰电极,构建了一种测定6-苄氨基嘌呤的新型的电化学方法。循环伏安实验表明,石墨烯修饰电极能显著降低6-苄氨基嘌呤的测定电位,提高其响应电流。6-苄氨基嘌呤在石墨烯修饰电极表面的电化学过程为扩散控制。在优化的实验条件下,6-苄氨基嘌呤与峰电流在浓度为1.0×10-8~1.0×10-6mol/L范围内呈现良好的线性关系,检测限为5.0×10-9 mol/L。考察了一些无机离子和有机化合物对6-苄氨基嘌呤测定的干扰,结果表明该传感器有较好的抗干扰能力。加标回收实验表明该修饰电极的回收率在91.0%~104.5%之间,表明该传感器能用于实际样品的检测。     

表面活性剂修饰的伏安传感器的制备及其应用

用碳粉61%、液体石腊20%和甘油19%制备碳糊电极,经0.060%Tween-80溶液修饰90 s后,得表面活性剂修饰的伏安传感器.在pH7.8的磷酸盐缓冲溶液中,ST在该传感器上于0.98 V处呈现灵敏阳极溶出伏安峰,利用此峰可测定痕量的磺胺噻唑,线性范围为8.5×10-9mol/L～5.0×10-6mol/L,检测下限为3.0×10-9mol/L.     

一种AlN基陶瓷微热板NO2气体传感器研究

针对传统硅基微热板半导体气体传感器存在的热稳定性差,工艺复杂等难点,采用良好热导特性的AlN陶瓷为衬底,利用柔性机械剥离工艺和半导体材料In2O3/Nb2O5/Pt厚膜工艺制备了NO2微热板气体传感器.传感器中间加热区周围采用热隔离结构设计,降低了加热区温度分布梯度,提高了温度效率.利用ANSYS有限元工具进行了热结构仿真分析和响应测试分析,验证了热隔离结构设计的合理性.气敏测试分析表明,传感器在不同加热功率条件下,对5×10-6~100×10-6的NO2气体都具有良好的气敏响应特性,经对比分析,在功率150 mW~200 mW时稳定性最佳,且响应速率小于60 s,恢复时间在100 s左右,可实现5×10-6~100×10-6浓度的NO2气体良好检测功能.     

ZnO纳米棒修饰的QCM气体传感器检测NH_3研究

主要介绍了ZnO纳米棒修饰的石英晶体微天平(QCM)气体传感器的制备与测试。采用两步法在石英晶振片表面制备直径为100 nm的ZnO纳米棒敏感膜,构成QCM NH3传感器。检测系统为自主研发的基于LabVIEW平台的QCM气体传感器频率测试软件。检测NH3的体积分数为5×10-6~50×10-6,响应时间均在10 s以内,最大频差值为10.9 Hz,响应最大频差值与NH3体积分数呈现良好的线性关系。室温条件下,ZnO纳米棒敏感膜可以完全实现吸附解吸过程,具有可逆性。该传感器性能稳定,响应灵敏,具有重复性。     

利用喷墨打印技术制备的类神经气体传感器

利用喷墨打印技术沉积生物高分子溶液的方法,打印出金的梳状微电极的阵列图形,并采用NaX型沸石分子筛作为敏感膜,研制了探测神经类毒气沙林的相似物DMMP气体的阻抗型传感器。电极图形使用简单的绘图软件autoCAD画出,通过简单改进过的办公用喷墨打印机在金衬底上打印一层自组装膜的阻挡层,经过湿法刻蚀后得到了梳状微电极阵列。将制得的传感器对1ppm(即1×10-6)DMMP气体进行检测,测得在0.01Hz处,其电阻的相对变化值为10.7%。与传统MEMS工艺相比较,喷墨打印方法制备传感器具有工艺步骤简化,成本低,可在柔性等不同材料上制作等优点,有着广泛的应用前景。     

羟基--碳纳米管气体传感器气敏性的仿真研究

采用羟基修饰后的碳纳米管作为气体传感器的气敏材料,会使其响应灵敏度提高。利用密度泛函理论研究了两种气体分子（ Cl2和H2 S）在本征单壁碳纳米管（ SWCNT）和羟基修饰过的单壁碳纳米管（ SWCNT—OH）上的吸附。分析其态密度图,并尝试改变气体分子在碳纳米管上的吸附位置与方向,从吸附能的大小、电荷转移量的多少、吸附距离的远近上,为本征SWCNT,SWCNT—OH的气敏性和两种气体在碳纳米管上的最佳吸附位置姿态提供对比与理论分析。     

Structure and electronic properties of "DNA-gold-nanotube" systems: a quantum chemical analysis

The development of novel DNA sensors is a crucial issue in the diagnosis of pathogenic and genetic diseases. We have used density functional theory (DFT) to investigate the performance of hybrid DNA sensors consisting of a gold atom (Au) deposited on two types of single-walled carbon nanotubes: armchair SWCNT(8,0)/Au and zigzag SWCNT(5,5)/Au and compared these with bare Au. We also chose adenine:thymine (A:T) as a Watson-Crick base pair of the DNA double helix. In the recognition probe, SWCNT/Au/A, adenine is immobilized on the SWCNT/Au supporter via its active N7 anchor point. After thymine hybridization (SWCNT/Au/A:T), the overall modulations compared with the original systems. Due to the complimentary functions of gold, which acts as a powerful electron withdrawing and transmitting group and of the SWNCTs, which act as electron collecting centers, respectively, the hybrid systems, "SWNCTs/Au", were found to exhibit more stability and sensitivity than the Au center alone. The changes in the HOMO-LUMO band gaps and in the atomic partial charges upon binding of thymine were rather small, but the change of the overall dipole moment was considerably larger in SWCNT/Au/A than it was in Au/A alone. The overall results suggest that the "SWCNTs/gold" system is a potential candidate for a nanostructure-based DNA sensor.     

Flexible vapour sensors using single walled carbon nanotubes

Thin, strongly adhering films of single-walled carbon nanotube bundles (SWNT) on flexible substrates such as poly(ethyleneterephthalate) (PET) were used for vapour sensing (hexane, toluene, acetone, chloroform, acetonitrile, methanol, water, etc.). These sensors are extremely easy to fabricate using the line patterning method. For example, ‘4-probe’ sensor patterns are drawn on a computer and then printed on overhead transparency (PET) sheets. These PET patterns were coated with films of electronically conductive SWNT bundles (1–2 μm thick) by dip-coating in aqueous surfactant-supported dispersions and mounted in glass chambers equipped for vapour sensing. Experiments conducted under saturated vapour conditions in air showed sensor responses that correlated well with solvent polarity [E_T(30) scale]. Similar results were obtained under controlled vapour conditions (no air) at 10,000 ppm. Control experiments using films of carbon black on PET (Aquadag-E^®), also prepared by the line patterning method, showed very little response to vapours under identical experimental conditions. The sensors are very flexible, e.g., they can be bent to diameters as small as 10 mm without significantly compromising sensor function.     

Ni掺杂SnO2花状微结构的制备及其气敏特性研究

采用水热法合成了纯SnO2和4 mol%Ni掺杂SnO2花状微结构.利用X射线衍射仪(XRD)、X射线能谱分析仪(EDS)和扫描电子显微镜(SEM)对其晶相、成分进行了表征,对制备的纯的和Ni掺杂SnO2传感器性能进行了测试.实验结果表明:Ni掺杂可以显著改善SnO2微结构的气敏特性.在最佳工作温度(280℃)条件下,4 mol%Ni掺杂SnO2传感器对100×10-6甲醇的响应可达到13.0,其响应是纯SnO2气体传感器的2.4倍.同时,其具有快速的响应/恢复时间(6 s/5 s),较低的检测极限(1×10-6),以及对甲醇的良好选择性.最后,对Ni掺杂SnO2气体传感器的气敏机理进行了分析讨论.     

气敏法动态浓度测量中的预测技术探讨

用实验测量了气敏传感器（ＭＱ２１１型）在气体浓度阶跃作用下的响应和恢复特性，发现它们均可用超越函数模型近似，以此为基础，建立了气每法动态测量中的智能预测技术，结果与实验基本一致，从而解决了气敏法测探中的滞后现象，研究中还发现并建立了快速测定气敏感器响应时间和恢复单时间的新方法。     

Development of a resistive compact slip sensor using dielectric elastomer

Tactile sensor for detecting slip is essential to safely grasp an object for a robot hand with a complicated structure and various functions. In this paper, sensors with three patterns in different forms are designed to sense slip moment through a resistance change. The slip sensors of novel design have flexible and stretchable to be used on the robot hand surface. For realizing these characteristics, acrylonitrile-butadiene rubber (NBR) is used as a substrate of the sensor. Graphene material is employed because of suitability for flexible substrate as an electrode. An imprint process to produce a micro-unit structure to sensor surface is newly developed. As a result, sensors have an extremely small structure that can operate suggested working principle perfectly. Parameters of the micro structure is confirmed by FEM simulation earlier. Experiments for performance of the developed sensors are conducted. Through results of experiments, the pattern that has the best performance to know slip moment was checked.

     

Millisecond-order response measurement for fast oxygen gas sensors

A novel method for the evaluation of fast response of oxygen gas sensors in terms of milliseconds is developed. Using the method of modulating oxygen partial pressure by changing the total pressure inside the test chamber, the millisecond-order measurement was succeeded. For the 100 Hz sign-wave operation, the measurement system generated the pressure changes from 180 to 220 kPa, corresponding to the change of oxygen partial pressure from 36 to 44 kPa. Using both jump-method and pressure modulation method, the response of the resistive oxygen sensors of cerium oxide thick films were evaluated at 1173 K and the kinetic mechanism of gas sensing was discussed. Their response times of t₉₀ obtained by square-wave change were measured to be 37 and 22 ms for high-to-low oxygen partial pressure and vice versa transition, respectively. The log–log plot of resistance of sensor and the frequency, pressure modulation spectra, was also evaluated at the same time and the kinetics of oxygen sensing was suggested to be diffusion-limited.     

酞箐气体传感器发展趋势

酞箐作为一种重要的气体敏感材料,有着良好的应用前景。根据实用的要求,采用了各种方法来改善传感器的气体敏感特性。介绍了酞箐气体传感器发展的趋势,包括加速响应、便于检测和应用、消除基线漂移的影响、提高选择性及微型化和多传感器集成化等方面。