三元复合材料PANI/Ag/MWNT的电化学行为和比电容

通过原位聚合的方式在银纳米粒子/多壁碳纳米管(Ag/MWCNT)复合材料的表面成功聚合苯胺单体制备了聚苯胺/银纳米粒子/多壁碳纳米管(PANI/Ag/MWCNT)三元复合材料苯．通过对三元复合材料的结构以及表面形貌进行分析,表明聚苯胺层完全包覆了Ag/MWCNT复合材料,形成了核壳式结构．同时银纳米粒子则以单质晶体的形态存在于多壁碳纳米管与聚苯胺层之间．三元复合材料电极在1 mol/L的KOH溶液中具有极低的阻抗,而与聚苯胺电极相比,这些复合材料电极则表现出更低的电阻、更高的电化学活性和更好的循环稳定性．尤其是当苯胺和Ag:MWCNTs质量比为5:5时,该复合材料电极在0.25 A/g的电流密度下表现出最大的比电容值为160 F/g．     

碳纳米管/聚苯胺纳米复合管的制备及其微波介电特性研究

用原位乳液聚合法在碳纳米管表面包覆聚苯胺，制备出了碳纳米管/聚苯胺一维纳米复合管.复合管的直径为50—80 nm，聚苯胺包覆层的厚度为20—30 nm，聚苯胺在碳纳米管表面以层状和枝晶状两种形态生长.研究了碳纳米管/聚苯胺复合管在2—18 GHz的微波介电特性.与纯碳纳米管相比，碳纳米管/聚苯胺复合管的介电常数的实部ε′和虚部ε″在2—18 GHz随频率变化较小，在低频波段介电常数值较小，作为微波吸收剂容易实现与自由空间的阻抗匹配，而且它的介电损耗角正切(tanδ=ε″/ε′)较高，是一种很好的微波吸收剂. 关键词： 碳纳米管 聚苯胺 微波介电特性 微波吸收剂     

聚苯胺/碳纳米管复合体的制备及其三阶非线性光学性能研究

通过原位吸附-受限生长聚合法成功制备了聚苯胺/碳纳米管(PANI/MWCNT)复合体.红外光谱和拉曼光谱证实了在碳纳米管(MWCNT)表面的包覆层为聚苯胺(PANI).紫外—可见吸收光谱表明随着MWCNT含量的增加PANI的吸收发生红移且强度提高.扫描电子显微镜和透射电子显微镜观察发现，PANI/MWCNT复合体直径为40—70nm，其中PANI的包覆层厚度约为15—20nm.利用四波混频方法测试它们的三阶非线性光学系数，结果发现PANI/MWCNT复合体的三阶非线性光学系数比纯PANI大，这说明在MWC 关键词： 碳纳米管 聚苯胺 复合体 三阶非线性光学系数     

不同厚度阴极修饰材料LiF对聚对苯乙炔MOPPV-SWNT-PbSe量子点复合材料太阳电池性能的影响

基于碳纳米管的良好导电性、激子传输性能和量子点聚合物复合材料高的光电转换性能,采用原位缩合法制备了聚合物聚(2-甲氧基-5-辛氧基)-对苯乙炔-功能化碳纳米管-硒化铅量子点复合材料.通过对复合材料的X射线衍射、透射电子显微镜和紫外可见吸收光谱研究,发现聚合物聚(2-甲氧基-5-辛氧基)-对苯乙炔,功能化碳纳米管与硒化铅量子点可以有效地复合,且功能化碳纳米管与聚合物聚(2-甲氧基-5-辛氧基)-对苯乙炔形成网状结构;硒化铅量子点尺寸为5.75nm,其可均匀地分散在聚合物聚(2-甲氧基-5-辛氧基)-对苯乙炔-功能化碳纳米管基体中形成包覆或镶嵌结构,并发生了光诱导电荷转移.通过对复合材料的光电性能研究发现,插入不同厚度阴极修饰材料LiF后其光电性能提高,且当LiF为3nm时,开路电压为0.558 V,短路电流为2.338 mA,填充因子为37.6%,转换效率为0.466%,与不插入修饰材料时相比复合材料光电性能提高了30%.     

聚苯胺/钡铁氧体复合材料的制备及电磁性能

"采用原位掺杂聚合法,将聚苯胺对粒径在60~80 nm的M型钡铁氧体颗粒(BaFe12O19)进行包覆,得到了具有导电性和磁性的复合材料．通过X射线衍射、傅利叶变换红外光谱仪、扫描电镜和透射电镜等测试手段对材料的形貌和结构进行了表征．结果表明：PANI链段与BaFe12O19颗粒之间存在着作用力．使用振动磁强计和四探针法测定了复合材料的磁性能与电性能,其中50%复合材料的饱和磁化强度为22.2 emu/g,电导率为0.069 S/cm．"     

聚(2-甲氧基-5-辛氧基)对苯乙炔/单壁碳纳米管复合材料的光致发光特性

采用原位聚合法在无水四氢呋喃(THF)溶液中制备了聚(2-甲氧基-5-辛氧基)对苯乙炔(MOPPV)/单壁碳纳米管(SWNTs)复合材料。通过对该复合材料的红外光谱、X射线衍射、透射电镜、扫描电镜等的研究,证实SWNTs已聚合到MOPPV上且被MOPPV紧密有效地包覆,形成了纳米线网状结构。通过紫外-可见(UV-Vis)吸收光谱和光致发光(PL)谱发现:随着SWNTs掺杂量的增加,该复合材料的吸收强度逐渐增强且最大吸收峰出现红移,其发光强度呈现先升高后降低的趋势,发光峰蓝移。当SWNTs掺杂质量分数为3.85%时,复合材料的发光强度最大,此时最大发光峰位较纯MOPPV蓝移8 nm。研究结果表明:在MOPPV中掺入一定量的SWNTs,能有效地增强复合材料的光致发光强度。     

碳纳米管掺杂对聚合物聚(2-甲氧基-5-辛氧基)对苯乙炔-PbSe量子点复合材料性能的影响

基于碳纳米管的良好导电性、激子传输性能和量子点聚合物复合材料高的光电转换性能, 采用原位缩合法制备了聚合物聚(2-甲氧基-5-辛氧基)-对苯乙炔(MOPPV)功能化碳纳米管(SWNT)-PbSe量子点复合材料, 通过对复合材料的X射线衍射、透射电子显微镜和紫外可见吸收光谱研究, 发现MOPPV, SWNT与PbSe量子点可以有效地复合, 且SWNT与MOPPV形成网状结构; PbSe量子点尺寸为5.75 nm, 其可均匀地分散在MOPPV-SWNT基体中形成包覆或镶嵌结构, 并发生了光诱导电荷转移.通过对复合材料的光电性能研究发现, 当MOPPV, SWNT, PbSe三者的质量比为1: 0.3 : 1 时其光电性能最好, 开路电压为0.556 V, 短路电流为2.133 mA, 填充因子为34.48%, 转换效率为0.452%, 与聚合物MOPPV-PbSe量子点复合材料材料相比, 光电性能提高了2–3倍. 关键词： 量子点 碳纳米管 复合材料 转换效率     

碳纳米管/金刚石复合材料的场发射特性

采用微波烧结方法制备了碳纳米管/金刚石复合材料。将碳纳米管和纳米金刚石粉末混合后研磨压片,然后在微波等离子气相沉积系统中采用微波烧结。利用扫描电镜对复合材料的表面形貌和微观结构进行了分析,结果显示碳纳米管比较均匀地分散于复合材料中,并在表面形成了发射微尖。利用二极管结构在动态真空室中对复合材料的场发射特性进行了研究,复合材料有较好的场发射特性,电流密度接近15mA/cm2。     

碳纳米管/聚二甲基硅氧烷复合薄膜的制备及力敏特性研究

针对传感器的敏感单元发展需求,提出了一种碳纳米管复合材料.该材料是以碳纳米管作为填充粒子,结合聚二甲基硅氧烷(PDMS)有机基体,采用超声共混方法制备的一种新型传感器敏感元件.详细分析研究了复合材料的制备工艺参数,以及在不同工艺参数下该复合材料的力敏特性.扫描电镜测试表明碳纳米管在PDMS中分散均匀且镶嵌良好.通过对不同体积分数的碳纳米管与PDMS复合材料进行电学性能测试,研究薄膜的"力-电阻"和"力-电容"耦合性能,测试了薄膜结构的力敏效应.计算得到复合薄膜材料的压阻灵敏度因子达到40,压电容灵敏度因子达到70.实验研究表明,通过改变碳纳米管与PDMS的比例,可以很好地调节其电子输运特性以及电阻和电容的应力敏感特性,可以为该类型的力敏材料在不同的力敏传感技术领域提供新的研究思路.     

新型六方晶型磁载TiO2纳米粒子的合成及其光降解性能

采用溶胶-凝胶法,在磁性Fe<,3>O<,4>表面包覆TiO<,2>,制备了一种新型六方晶型纳米TiO<,2>/Fe<,3>O<,4>光催化复合材料.X射线衍射(XRD),透射电镜(TEM)对材料形态结构及包覆情况的分析,显示TiO<,2>包覆在Fe<,3>O<,4>表面,对染料废水光催化降解的模拟研究表明,该复合材料...     

Comparative impact of doping nano-conducting polymer with carbon and carbon oxide composites in alkyd binder as anti-corrosive coatings

This study concentrated on producing anticorrosive coating depending on alkyd resin blended with polyaniline-carbon allotropes composites as filler. Polyaniline (PANI) and its composites were produced by doping of PANI with the carbon allotropes (graphene and multi-walled carbon nanotubes) and carbon-oxide allotropes (graphene oxide and multi-walled carbon nanotubes oxide) in different ratios through in situ chemical polymerization. The morphology of PANI and its composites were examined by transmission electron microscope (TEM), which proved that PANI composites appeared as a shell layer in core/shell structure with various overlay thickness depending on the adsorption type for polyaniline. The performance of the prepared coatings in cabinet salt agrees with electrical conductivity values where the best PANI/composite in conductivity value is the most efficient as an anti-corrosive coating.     

Microstructural investigations of zirconium oxide—on core–shell structure of carbon nanotubes

Single-walled carbon nanotubes and multi-walled carbon nanotubes/ZrO₂ nanocomposites were obtained by isothermal hydrolyzing and chemical precipitation method for both the carbon nanotubes. The coating was taken place by dispersion of both the carbon nanotubes in ZrOCl₂·8H₂O aqueous solution. However, a highly conformal and uniform monoclinic zirconia coating was deposited on multi-walled carbon nanotubes rather than single-walled carbon nanotubes by this new and simple method. Also, it has been observed that the thickness of the individual carbon nanotube after zirconia coating was increased by isothermal hydrolyzing process rather than traditional chemical precipitation method and it has been confirmed by high-resolution transmission electron microscopy study.     

Effect of oxyfluorination on gas sensing behavior of polyaniline-coated multi-walled carbon nanotubes

Polyaniline-coated multi-walled carbon nanotubes were prepared by in situ chemical polymerization method for the novel sensing materials of ammonia gas. The thickness of the polyaniline coatings was controlled by the oxyfluorination treatment on the multi-walled carbon nanotubes. The oxyfluorination with higher oxygen content produced the more hydrophilic functional groups on the surface of multi-walled carbon nanotubes. Both the resistivity change and the response time were significantly improved with high repeatability using the more hydrophilic multi-walled carbon nanotubes which were modified with oxyfluorination.     

Preparation and modification of well-aligned CNTs grown on AAO template

Anodic aluminum oxide (AAO) template was prepared by a two-step anodization method and cobalt particles were carefully deposited at the bottom of pores of the template. CVD method was used to grow carbon nanotubes (CNTs) on the template with this cobalt as catalyst and C₂H₂ as carbon source. Well-aligned carbon nanotubes were obtained perpendicular to the substrate. To modify the CNTs, ultrasonic treatment of the samples in alcoholic (or water) was applied and the results showed that the length of CNTs became equalized and their tips were opened without catalyst particles due to ultrasonically cutting off CNTs for the upper parts out of AAO pores. The mechanism is also discussed.     

Resonant Raman spectroscopy and spectroelectrochemistry characterization of carbon nanotubes/polyaniline thin film obtained through interfacial polymerization

Thin, transparent, and self‐assembled films of neat polyaniline and polyaniline/carbon nanotube nanocomposites were deposited over glass substrates by interfacial polymerization. The effect of the carbon nanotubes on the structure and conformation of the polyaniline, and the type of interaction between the polymer and the nanotubes, have been studied by resonant Raman spectroscopy and UV–Vis and Raman spectroelectrochemistry. The results indicate clearly that the carbon nanotubes induce important changes in the electronic structure of the polymer, resulting in a more polaronic organization. Additionally, an effective interaction between the polymer and the nanotube, based on a polyaniline‐to‐nanotube charge transfer, is proposed in this work. Copyright © 2012 John Wiley & Sons, Ltd.     

Anatase nanotubes as support for platinum nanocrystals

Anatase nanotubes were successfully produced via the sol–gel process involving organic titanium precursors and multi-walled carbon nanotubes as template. Controlled heat treatments were carried out in order to remove any solvents and to crystallise the initial amorphous titania coating into anatase. In order to use these structures for catalyst support, platinum particles were formed by the impregnation with hexachloroplatinic acid and subsequent calcination and reduction to obtain a final loading of 4 wt% platinum. This impregnation step was carried out either with the carbon nanotube former still present with subsequent heat treatment to remove the carbonaceous template (sample A) or with the carbon nanotube former already removed (sample B). The materials were characterised by X-ray diffraction, scanning electron microscopy and transmission electron microscopy.     

Photocatalysis and wave-absorbing properties of polyaniline/TiO2 microbelts composite by in situ polymerization method

Polyaniline (PANI)/TiO₂ composite is prepared by in situ polymerization of polyaniline on the surface of TiO₂ template obtained by the sol-gel process via cotton template. The TiO₂ microbelts are prepared by sol-gel method using the absorbent cotton as template for the first time. Then the TiO₂ microtubules are used as template for the preparation of polyaniline/TiO₂ composites. The structure, morphology and properties of the composites are characterized with scanning electron microscope (SEM), IR, Net-wok Analyzer. A possible formation mechanism of TiO₂ microtubules and polyaniline/TiO₂ composites has been proposed. The effect of the mol ratio of polyaniline/TiO₂ on the microwave loss properties and photocatalysis properties of the composites is investigated.     

Synthesis of carbon nanotubes by CVD: Effect of acetylene pressure on nanotubes characteristics

The effect of acetylene partial pressure on the structural and morphological properties of multi-walled carbon nanotubes (MWCNTs) synthesized by CVD on iron nanoparticles dispersed in a SiO₂ matrix as catalyst was investigated. The general growing conditions were: 110 cm³/min flow rate, 690 °C synthesis temperature, 180 Torr over pressure and two gas compositions: 2.5% and 10% C₂H₂/N₂. The catalyst and nanotubes were characterized by HR-TEM, SEM and DRX. TGA and DTA were also carried out to study degradation stages of synthesized CNTs. MWCNTs synthesized with low acetylene concentration are more regular and with a lower amount of amorphous carbon than those synthesized with a high concentration. During the synthesis of CNTs, amorphous carbon nanoparticles nucleate on the external wall of the nanotubes. At high acetylene concentration carbon nanoparticles grow, covering all CNTs’ surface, forming a compact coating. The combination of CNTs with this coating of amorphous carbon nanoparticles lead to a material with high decomposition temperature.     

Preparation of graphene/polyaniline-modified carbon nanotubes and their electrochemical properties in microbial fuel cell

Using chemical vapor deposition methods to prepare carbon nanotubes growing in situ on a carbon felt, graphene and polyaniline were applied to the carbon felt for modifying carbon nanotubes. Microbial fuel cell was constructed with graphene/polyaniline-modified carbon nanotubes as anode, graphite as cathode, and glucose solution as substrate. The effects of electrodes, substrate concentration, and temperature on the properties of microbial fuel cell have been studied. At 38 °C using glucose solution of 1450 mg L^?1 and external resistance of 2500 Ω, the optimum output voltage of 687 mV and removal rate of 83% for chemical oxygen demand were obtained in the microbial fuel cell. The prepared nanomaterials are stable and reusable.