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。     

基于静电纺丝法制备P(VDF-TRFE) /石墨烯(GR)薄膜的柔性复合压电纳米发电机

提出了一种利用静电纺丝工艺制备P(VDF-TRFE)/石墨烯(Graphene,以下简称GR)复合纳米纤维薄膜的方法并对其压电性能进行了研究。首先,以复合薄膜为功能层设计并制备了柔性压电纳米发电机。使用扫描电镜(SEM)表征了复合纤维薄膜表面的微观形貌。其次,对各纳米发电机样品进行了压电响应对比实验,含0.2%石墨烯的P(VDF-TRFE)/GR纳米发电机的开路输出电压、短路输出电流峰值分别为12.3 V、1.41 μA,比纯P(VDF-TRFE)样品分别增加了大约2.0倍、2.2倍。此外,通过理论分析和周期激振测试探究了纳米发电机电响应输出的影响因素和规律,证实在激振器驱动信号150 mV^300 mV振幅、10 Hz^30 Hz频率的范围内,其开路输出电压随着其振幅和振动频率增大而增大,电容充电效率随其振幅增大而增大。     

微乳液法制备纳米WO3粉体

采用CTAB/正丁醇/正辛烷/水微乳体系制备了纳米WO3粉体,并用X射线衍射仪、透射电子显微镜对WO3粉体进行了表征,研究含水量、煅烧温度对WO3粉体的物相结构、粒径大小和形貌的影响.研究表明:随着含水量增加,WO3颗粒的粒径逐渐增大;随着煅烧温度的升高,出现了单斜晶系和三斜晶系的WO3颗粒,WO3颗粒不但粒径逐渐增大,形貌发生变化,而且团聚更加严重.     

新型纳米铜/石蜡/PVP温敏复合材料的制备及其性能

采用高能球磨法制备了纳米铜/石蜡/PVP温敏复合材料.用扫描电镜(SEM)、高分辨透射电镜(TEM)和傅立叶变换红外光谱仪( FTIS)对复合材料的微观形貌和结构进行了表征,并测试了复合材料的膨胀性、温敏性和稳定性.结果表明,石蜡/PVP复合有机物对铜粒的包覆效果良好,球磨100h的复合颗粒近似球形,粒径约为100 n...     

基于Au NPs-CeO2@PANI纳米复合材料固定化酶的葡萄糖生物传感器

制备了一种基于金纳米粒子(Au NPs)、氧化铈纳米颗粒(CeO2)和导电聚苯胺(PANI)的具有核壳结构的纳米复合材料(Au NPs-CeO2@PANI),利用该纳米复合材料和壳聚糖形成的复合膜成功实现了对葡萄糖氧化酶(GOD)的固定.采用透射电镜和X射线衍射对Au NPs-CeO2@PANI材料进行了表征.电化学方法研究了传感器性能,结果表明基于Au NPs-CeO2@PANI纳米复合材料修饰的葡萄糖生物传感器线性范围为6.2×10-6 mol/L～2.8×10-3 mol/L,响应时间为5 s,检测下限为1.0×10-6 mol/L;相同条件下Au NPs-CeO2@PANI纳米复合材料修饰的电极也显示出了比单一或二者复合的纳米材料修饰电极更优越的性能.     

WO_3/Si-NPA复合薄膜的电容湿度传感性能研究

制备了基于硅纳米孔柱阵列(Si-NPA)的WO3/Si-NPA复合薄膜,并对其表面形貌进行了表征,研究了其电容湿度传感性能和基点电容的温度漂移。研究表明:WO3/Si-NPA继承了衬底Si-NPA规则的阵列结构的表面形貌特征,WO3的沉积形成了连续的WO3薄膜,WO3/Si-NPA是一种典型的纳米复合薄膜。室温下,WO3/Si-NPA的电容值随测试频率的增加而单调减小,但其灵敏度则在100 Hz时达到最大值。在此测试频率下,当环境的相对湿度从11%RH增加到95%RH时,元件的电容增量高达16 000%,显示WO3/Si-NPA对环境湿度有较高的灵敏度。同时,电容的湿度响应曲线显示出很好的线性。对其基点电容的温度稳定性研究表明:WO3/Si-NPA用作湿度传感的最佳工作温度区为15~50℃。     

电纺PANI/PEO纳米纤维传感器制备与应用

采用静电纺丝法制备了聚苯胺/聚环氧乙烷（ PANI/PEO）纳米纤维,研究了电压、接收距离对电纺PANI/PEO纳米纤维直径的影响,对电纺参数进行了优化。通过对电纺接收端的控制,制备了平行纳米纤维阵列,实现了纳米纤维的定向排布;通过对电纺射流沉积次数的控制,制备了PANI/PEO纳米单纤维传感器,并对NH3进行了气敏性测试。结果表明：当电纺电压为20 kV且接收距离为20 cm时,获得的PA-NI/PEO纳米纤维直径为105 nm,且形貌较佳,在此优化参数条件下制备的单纤维PANI/PEO纳米传感器在常温下对低浓度的NH3有良好的线性响应输出。     

PVP对溶剂热法合成Fe_3O_4/石墨烯复合粉体的影响

采用溶剂热法合成了Fe_3O_4/石墨烯复合粉体,并通过X射线衍射(XRD)、傅里叶转换红外光谱(FT-IR)、扫描电子显微镜(SEM)等测试手段,分析了溶剂热反应过程中PVP的添加与否对Fe_3O_4/石墨烯结构和形貌的影响。结果表明,若反应过程中添加PVP,所得样品中Fe_3O_4颗粒尺寸变小,但不影响Fe_3O_4的结构以及其颗粒在石墨烯上的负载;将溶剂热合成产物Fe_3O_4/G和Fe_3O_4/G-PVP分别在氩气保护下500C烧结后,Fe_3O_4/G-500样品中Fe_3O_4颗粒仍然完好的负载在石墨烯片上,样品Fe_3O_4/G-PVP-500中有大量的Fe_3O_4颗粒从石墨烯片上脱落,同时Fee_3O_4颗粒产生了粉碎,以此分析了PVP在溶剂热合成过程中的作用。     

纳米Fe3O4表面聚合接枝的XPS分析

采用在纳米Fe3O4颗粒表面通过引入过氧基因引发甲基丙烯酸甲酯(MMA)聚合的方法,在纳米Fe3O4颗粒表面接枝了PMMA.采用傅立叶红外光谱(IR-FT)检测粉体表面官能团,采用X射线光电子能谱(XPS)检测粉体表面化学键变化,采用高分辨透射电镜(HRTEM)观察改性后粉体的表观形貌.结果表明纳米Fe3O4呈球形,颗粒间团聚不明显,在纳米Fe3O4表面成功地包覆了PMMA,PMMA以化学接枝的方式结合在Fe3O4颗粒表面.     

基于高压静电纺丝法制备P(VDF-TrFE)/ZnO/GR复合膜压电性能的研究

提出了一种利用高压静电纺丝法制备P(VDF-TrFE)/ZnO/Graphene(以下简称GR)复合纳米纤维薄膜的方法，并对其压电性能进行了研究。首先，利用扫描电镜（SEM）观测复合薄膜的表面形貌并分析其X射线衍射（XRD）图谱。其次，将薄膜封装为三明治结构的压电纳米发电机(PNG)并研究了其压电性能。结果表明，含10%ZnO、0.1%GR的P(VDF-TrFE)/ZnO/GR复合薄膜压电纳米发电机开路输出电压和短路输出电流峰值为12.6V、7.88μA，约是纯P(VDF-TrFE)薄膜的2.7倍、3.1倍。在激振力大小3.5N，频率为5HZ的条件下P(VDF-TrFE)/ZnO/GR压电纳米发电机的最大瞬时输出功率为33.85μW，持续激振21分钟后，LTC3588-1毫微功率能量收集电源可以稳定输出3.3V电压1.5s。P(VDF-TrFE)/ZnO/GR压电纳米发电机具有良好的压电性能，具有成为自供电设备的潜力。     

Sn-Zn-Cu复合氧化物气敏元件的制备与性能

从环境材料的理念出发,以SnO2,ZnO和CuO 3种物质为原料,直接混合烧结制得6种不同成分比例的Sn-Zn-Cu复合氧化物气敏元件。对这6种气敏元件进行性能测试,结果发现:SnO2∶ZnO∶CuO摩尔比为1∶1∶1的气敏元件对丁烷有较高的灵敏度、较好的选择性和响应恢复性能,具有应用开发的价值。     

土壤全氮含量与碳氮比的高光谱反射估测影响因素研究

基于土壤高光谱反射特征可以实现土壤全氮(TN)含量与碳氮比(C∶N)等土壤属性的快速、无损测定,但其估测模型受土壤颗粒粒径水平与光谱指数(预处理)等因素影响。通过研磨准备2、0.25和0.15 mm共3个水平颗粒粒径的土样,分析了原始(RAW)及多次散射校正MSC(Multiple Scattering Correction)、一阶微分FD(First Derivative)、连续统去除CR(Continuum Removal)等预处理的土壤反射光谱与TN含量、碳氮比变化之间的关系,发现土壤研磨可以提高反射光谱对TN含量变化的响应,而FD、CR与MSC等光谱预处理能够明显缩小不同颗粒粒径水平土样的光谱反射-TN含量、碳氮比相关性差异。结果表明:0.25 mm颗粒粒径土样的FD预处理光谱在2 250 nm和2 280 nm处分别与TN含量、碳氮比变化存在最大相关,但最大相关单波段线性回归模型的TN含量、碳氮比估测精度不如全波段光谱PLSR模型。其中,0.25 mm土样RAW光谱全波段PLSR模型估测TN含量的表现最佳(RPD=3.49,R²=0.92,RMSEP=0.1 g/kg);而碳氮比的估测结果并不十分理想,其最优估测模型(0.25 mm土样FD预处理的全波段PLSR模型)的RPD仅为1.21,可能与土样的碳氮比变化范围较小有关,在以后的研究中可以尝试采集更多的样本数量或土壤类型,使训练样本具有较大的变量范围,以取得较好的估测效果。     

A computer-controlled near-field electrospinning setup and its graphic user interface for precision patterning of functional nanofibers on 2D and 3D substrates

Electrospinning is a versatile technique for production of nanofibers. However, it lacks the precision and control necessary for fabrication of nanofiber-based devices. The positional control of the nanofiber placement can be dramatically improved using low-voltage near-field electrospinning (LV-NFES). LV-NFES allows nanofibers to be patterned on 2D and 3D substrates. However, use of NFES requires low working distance between the electrospinning nozzle and substrate, manual jet initiation, and precise substrate movement to control fiber deposition. Environmental factors such as humidity also need to be controlled. We developed a computer-controlled automation strategy for LV-NFES to improve performance and reliability. With this setup, the user is able to control the relevant sensor and actuator parameters through a custom graphic user interface application programmed on the C#.NET platform. The stage movement can be programmed as to achieve any desired nanofiber pattern and thickness. The nanofiber generation step is initiated through a software-controlled linear actuator. Parameter setting files can be saved into an Excel sheet and can be used subsequently in running multiple experiments. Each experiment is automatically video recorded and stamped with the pertinent real-time parameters. Humidity is controlled with ±3% accuracy through a feedback loop. Further improvements, such as real-time droplet size control for feed rate regulation are in progress.     

Composites of carboxylate-capped TiO2 nanoparticles and carbon black as chemiresistive vapor sensors

Titanium (IV) dioxide (TiO₂) nanoparticles (NPs) with a 1-5 nm diameter were synthesized by a sol-gel method, functionalized with carboxylate ligands, and combined with carbon black (CB) to produce chemiresistive chemical vapor sensor films. The TiO₂ acted as an inorganic support phase for the swellable, organic capping groups of the NPs, and the CB imparted electrical conductivity to the film. Such sensor composite films exhibited a reproducible, reversible change in relative differential resistance upon exposure to a series of organic test vapors. The response of such chemiresistive composites was comparable to, but generally somewhat smaller than, that of thiol-capped Au NPs. For a given analyte, the resistance response and signal-to-noise ratio of the capped TiO₂-NP/CB composites varied with the identity of the capping ligand. Hence, an array of TiO₂-NP/CB composites, with each film having a compositionally different carboxylate capping ligand, provided good vapor discrimination and quantification when exposed to a series of organic vapors. Principal components analysis of the relative differential resistance response of the sensor array revealed a clear clustering of the response for each analyte tested. This approach expands the options for composite-based chemiresistive vapor sensing, from use of organic monomeric or polymeric sorbent phases, to use of electrically insulating capped inorganic NPs as the nonconductive phase of chemiresistive composite vapor sensors.     

Preparation of Ag–Au nanoparticle and its application to glucose biosensor

In this paper, Ag–Au nanoparticles are produced in sodium-bis(2-ethylhexyl)-sulfosuccinate (AOT)–cyclohexane reverse micelle system. The properties of the obtained nanoparticles are characterized with transmission electron microscope (TEM) and UV–vis absorption spectrophotometer. Glucose biosensors have been formed with glucose oxidase (GOx) immobilized in Ag–Au sol. GOx are simply mixed with Ag–Au nanoparticles and crosslinked with a polyvinyl butyral (PVB) medium by glutaraldehyde. Then a platinum electrode is coated with the mixture. The effects of the various molar ratios of Ag–Au particles with respect to the current response and the stability of the GOx electrodes are studied. The experimental results indicate the current response of the enzyme electrode containing Ag–Au sol increase from 0.32 to 19 μA cm⁻² in the solution of 10 mM β-d-glucose. In our study, the stability of enzyme electrodes is also enhanced.     

Polycrystalline tungsten oxide nanofibers for gas-sensing applications

Tungsten oxide nanofibers were successfully prepared via thermal treatment of electrospun composite nanofibers consisting of polyvinylpyrrolidone (PVP) and tungstic acid at 500 °C in air. The morphology, crystal structure, and chemical composition of the nanofibers were characterized by SEM, EDX, TEM, XRD, and FT-IR before and after the thermal treatment. It was confirmed that the calcination process was responsible for the removal of PVP component and the growth of crystalline WO₃. The resulting tungsten oxide nanofibers, which had a rough surface morphology and an average diameter of around 40 nm, were found to be formed by the axial agglomeration of prolate spheroid-like WO₃ nanoparticles with monoclinic crystalline phases. Gas-sensing measurements of the polycrystalline WO₃ nanofiber mats were performed upon exposure to ammonia gas. They demonstrated n-type sensing response and sensitive NH₃ detection up to 10 ppm with a well-defined relationship between the concentration and detection response at an operating temperature of 300 °C. These results were interpreted by applying the space-charge layer model used in the semiconducting metal-oxide sensor systems.     

高灵敏光波导传感器检测H2S气体

将甲基绿-聚乙烯醇薄膜固定在钾离子(K )交换玻璃光波导表面,研制出一种光学硫化氢气体传感器.实验结果表明,本传感器对浓度在20×10-9 ～1.3×10-6范围内的硫化氢气体有良好的线性响应(R= 0.989 7)和快速响应(t0.9小于3 s).本传感器具有灵敏度高、可逆性好、重现性高、成本低,结构简单和易制作等特点.     

MWCNTs/nano-CeO_2/PANI修饰的H_2O_2传感器

采用循环伏安和滴涂的方法在玻碳电极上制备出一种均匀且具有高电活性聚苯胺(PANI)/多壁碳纳米管(MWCNTs)/纳米氧化铈(nano-CeO2)复合膜。从膜的厚度、pH值、碳纳米管(CNTs)与nanoCeO2的质量比等方面系统地研究了复合膜探测H2O2浓度的各影响因素。结果表明:循环伏安聚合25圈的聚苯胺分散和固定CNTs,nano-CeO2,以及辣根H2O2酶的能力较好,且以CNTs与nano-CeO2的质量比为15∶1的复合膜在pH=6.4的缓冲溶液中具有较高的电活性。该复合膜修饰的电极对H2O2具有良好的响应电流,较快的响应时间(5 s),较宽的检测范围为5.0×10-6~3.95×10-4mol/L,较低的检出极限7.6×10-7mol/L(S/N=3 dB)。