碳纳米管的表面改性及在铜基复合材料中的应用

对碳纳米管进行表面改性,能够显著提高碳纳米管的表面活性、分散稳定性及与基材的结合性,提高其在复合材料中的增强效果。以电化学制备石墨烯量子点(GQDs)作为分散剂和交联剂,对多壁碳纳米管表面(MWCNTs)进行非共价键改性得到MWCNTs/GQDs复合材料。并将改性后的MWCNTs/GQDs复合材料与商品化超细铜粉进行复合,得到具有良好导电性和抗氧化性的铜基复合材料(MWCNTs/GQDs/Cu)。结果表明,水溶液中,GQDs通过π-π键吸附在MWCNTs表面,使MWCNTs的稳定浓度高达1.0 g/L。3.0%(质量分数)的MWCNTs/GQDs复合材料与商品化超细铜粉复合后,其电导率提高5.67%IACS,抗氧化温度提高53.0℃。     

聚对苯二甲酸乙二醇酯共价接枝多壁碳纳米管及其表征

通过两步法将聚对苯二甲酸乙二醇酯(PET)分子链共价接枝到多壁碳纳米管(MWCNTs)表面,成功地制备了PET/MWCNTs复合材料。聚丙烯酰氯共价接枝MWCNTs的表面具有多个可反应的酰氯基团,通过与PET端羟基间的反应,以聚丙烯酰氯为中间聚合物层,成功将PET分子链接枝到了碳纳米管表面。采用傅立叶变化红外光谱(FT-IR)、透射电镜(TEM)、核磁(1H-NMR)和热失重分析(TGA)对接枝产物进行了表征,结果表明,PET分子已通过共价接枝的方式接枝到碳纳米管表面,被接枝聚合物的量约为MWCNTs的96%,该接枝聚合物层的存在将有利于多壁碳纳米管与PET树脂间相容性的提高,从而使PET/MWCNTs复合材料的性能得到提高。     

沉积位置对脉冲激光沉积纳米Si晶薄膜微观结构的影响

在4.0×10-4Pa的真空条件下,采用脉冲激光烧蚀技术在单晶Si衬底和石英衬底上制备了非晶纳米Si薄膜.在N2气氛下,经过900℃热退火得到纳米Si晶薄膜.采用表面台阶测试仪、扫描电子显微镜、拉曼光谱仪等检测手段对样品不同位置的微观结构进行了表征.测量结果表明制备的纳米Si晶薄膜厚度及其晶粒尺寸分布不均匀,随着测量点与样品沉积中心距离的增加,薄膜的厚度逐渐减小,纳米Si晶粒的尺寸逐渐增大.从脉冲激光烧蚀动力学的角度对实验结果进行了定性的分析.     

铜基碳纳米管复合薄膜电沉积制备工艺

为获得碳纳米管分布均匀且导电性良好的铜基碳纳米管复合材料,用超声辅助搅拌复合电沉积方法制备了Cu/MWCNT复合薄膜.采用扫描电子显微镜(SEM)、四探针电阻率仪等研究了电沉积过程中复合电镀液中碳纳米管浓度、电镀液p H值、脉冲电流密度等各项电沉积工艺参数以及不同退火温度对复合薄膜的组织形貌和电阻率的影响规律.结果表明:改变镀液中碳纳米管含量和电镀液的p H值可以改变镀层中碳纳米管的含量及分布,MWCNTs质量浓度升高到2 g/L时,复合薄膜中MWCNTs的质量分数达2.17%;改变电流密度可以细化镀层组织并改善碳纳米管在镀层中的分布,从而提高镀膜的致密度并降低镀层的电阻率;合适的热处理温度可以改善薄膜结晶度和致密度,并提高导电性.镀液中MWCNTs质量浓度为2 g/L,电镀液p H为2,电流密度为20 A/dm2,电镀时温度在25℃且加入超声辅助搅拌时,所得到的复合镀膜经400℃退火后电阻率最低.     

多壁碳纳米管-还原氧化石墨烯杂化薄膜导电性能的调控

以氧化石墨烯(Graphene oxide,GO)水溶胶作溶剂和表面活性剂,将不同质量分数的多壁碳纳米管(Multi-walled carbon nanotubes,MWCNTs),通过超声空化作用分散于其中得到稳定均质的多壁纳米管/氧化石墨烯(MWCNT-GO)悬浮液。采用微滤自组装法制备MWCNT-GO杂化薄膜,然后将其置于真空干燥箱中进行低温(200℃)热处理1 h以脱除GO中的大部分含氧官能团,即得部分还原的多壁碳纳米管-还原石墨烯(MWCNT-RGO)杂化薄膜。结果表明:MWCNT-GO杂化薄膜呈现均质层状的"三明治"式结构,MWCNTs与GO形成3D交联导电网络,通过控制MWCNTs的添加量和低温热处理,可实现氧化石墨烯导电性的恢复和有效调控。随着MWCNTs含量的增加,所得MWCNT-GO杂化薄膜的导电率增加。掺杂质量分数50%的MWCNTs所制MWC-NT-GO-50杂化薄膜的导电率为1 120 S/m,经200℃热处理后,导电率高达5 380 S/m。     

脉冲激光沉积法制备Pt薄膜的研究

采用脉冲激光沉积技术在(0001)取向的蓝宝石基片上外延生长了Pt单晶薄膜,研究了沉积温度和激光能量对Pt薄膜的晶体结构,表面形貌及电学性能的影响规律.X射线衍射(XRD)分析结果表明,在沉积温度650℃、激光脉冲频率1Hz和激光能量280mJ的条件下,制备得到的Pt(111)单晶薄膜,其(111)面ω摇摆曲线半高宽(FWHM)仅为0.068°.原子力显微镜(AFM)分析表明外延的Pt薄膜表面具有原子级平整度,其表面均方根粗糙度(RMS)约为1.776nm.四探针电阻测试结果显示薄膜方阻为1/962Ω/□,满足铁电薄膜的制备工艺对Pt底电极的要求.     

多壁碳纳米管的表面功能化及分散性研究

多壁碳纳米管(MWCNTs)分别经混合、强酸氧化浸泡和酰氯化处理后,再与9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物(DOPO)的衍生物(DHDOPO)进行接枝反应得到表面功能化的MWCNTs。利用傅里叶变换红外光谱仪(FT-IR)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、热重分析仪(TGA)、紫外-可见分光光度仪(UV-Vis)和沉降实验等分别表征改性前后MWCNTs的结构和表面形态,估算DHDOPO在MWCNTs表面的相对接枝率,研究改性前后MWCNTs在乙醇中的分散性。结果表明,MWCNTs经混合强酸氧化后表面出现羧基;DHDOPO在MWCNTs上的相对接枝率为51%;混合强酸氧化和表面接枝DHDOPO的MWCNTs在无水乙醇中具有良好的分散性。     

双亲无规共聚物修饰碳纳米管/环氧树脂复合材料的制备与性能

通过自由基聚合法制备无规共聚物聚甲基丙烯酸缩水甘油酯/N-乙烯基咔唑P(GMA-co-NVC),并将其对多壁碳纳米管(MWCNTs)进行非共价键表面修饰得到P(GMA-co-NVC)/MWCNTs,再与环氧树脂(EP)复合,采用浇注成型法制备聚合物改性碳纳米管/环氧树脂复合材料。通过拉伸实验、电阻率测试和差式扫描量热法研究聚合物改性碳纳米管对环氧树脂力学、电学和热学性能的影响。结果表明:修饰后的碳纳米管比原始碳纳米管对环氧树脂有更明显的增强和增韧作用,当P(GMA-co-NVC)/MWCNTs质量分数为0.25%时,复合材料的体积电阻率为106Ω·m,相比于纯环氧树脂(1014Ω·m)下降了8个数量级,玻璃化转变温度(Tg)也由144℃提高至149℃。     

脉冲激光沉积生长单相的Nd_(1.85)Ce_(0.15)CuO_4薄膜及其激光感生热电电压效应

采用脉冲激光沉积(PLD)技术,在SrTiO3单晶衬底表面外延生长单相的1.85 Ce0.15 CuO4(NCCO)薄膜,并首次在斜切衬底上生长的NCCO薄膜中探测到激光感生热电电压(LITV)信号.实验研究表明,在低沉积温度、高沉积氧压和较大的激光脉冲重复频率下生长的NCCO薄膜中存在Nd1-xCexO<<1.75>,(NCO)杂相,是由于衬底表面吸附粒子扩散迁移困难所致;而高温下真空退火导致杂相的产生,则与NCCO的结构相变引起的热分解有关.通过提高沉积温度、降低沉积氧压和激光脉冲重复频率、并采用低温(T≤800℃)真空退火的方式,可以抑制杂相的形成.制备得到的单相的NCCO外延薄膜是一种新型的原子层热电堆材料,能量为1mJ的紫外脉冲激光的辐照,可以在倾斜的NCCO薄膜中诱导产生0.8V的LITV信号.     

CdS/CNT-TiO2光催化剂的合成及其对亚甲基蓝的光催化降解（英文）

采用多壁碳纳米管(MWCNTs)为载体,分别以醋酸镉((CH3COO)2Cd.2H2O)和硫化钠(Na2S.5H2O)为镉源和硫源,经简单逐滴滴入途径制备了CdS/CNT复合材料。再以四丁氧基钛(TNB)为钛源,苯为溶剂,成功地将二氧化钛(TiO2)纳米粒子沉积在CdS修饰的MWCNTs表面而得到CdS/CNT-TiO2光催化剂。利用N2吸附等温线、扫描电子显微镜、X射线衍射、能量分散性X射线分析以及透射电子显微镜对所制CdS/CNT-TiO2光催化剂进行表征。CdS/CNT-TiO2复合材料呈多孔结构,MWCNTs均匀分散在材料中,且未出现明显的TiO2和CdS纳米颗粒团聚体。该材料在紫外和可见光照射下对亚甲基蓝具有优异的降解活性。这不仅归因于TiO2对自由基的反应和MWCNTs吸附能力,且归因于引入窄带隙半导体CdS,使粒子在MWCNTs表面的电子转移速率得到提高。     

Fabrication of multi-walled carbon nanotube reinforced polyelectrolyte hollow nanofibers by electrospinning

Hybrid hollow multi-walled carbon nanotubes (MWCNTs)/polyelectrolytes (PE) nanofibers were prepared by a combination of the electrospinning method and layer-by-layer (LbL) technique. The mixed polystyrene (PS)/MWCNTs nanofibers were obtained by electrospinning method, which were employed as templates to self-assembly multilayered polyelectrolytes by LbL technique. Hollow MWCNTs/PE nanofibers were obtained by selectively removed part of the template: PS, which is confirmed by Raman spectra, transmission electron microscopy (TEM) and scanning electron microscopy (SEM).     

交流信号检测的多壁碳纳米管湿度传感器模型(英文)

为研究交流信号检测的多壁碳纳米管(MWCNTs)湿度传感器模型,通过扫描电子显微镜对传感器敏感薄膜(MWCNTs-SiO2薄膜)的孔隙结构进行观察,并使用表面积与孔隙(ASAP)分析系统对薄膜孔隙率进行分析.利用Debye方程对敏感薄膜中凝聚出液态水介电损耗的描述建立传感器模型.为了验证该传感器模型,制作了一种基于MWCNTs-SiO2的电导型湿度传感器,在100 kHz测试频率下,对不同相对湿度环境中的传感器电导值进行测试,利用测试结果与所建立模型进行拟合,发现R2大约为0.979,可见该模型可以用来描述传感器湿敏特性.     

Fabrication of 3D carbon nanotube/porous carbon hybrid materials

Three dimensional hybrid carbon materials have been prepared using different biomass-derived porous carbons as catalyst supports for growing multi-walled carbon nanotubes (MWCNTs) via a chemical vapor deposition method. The nickel catalyst-loaded supports before and after growing MWCNTs were characterized by scanning and transmission electron microscopy, Fourier transform infrared spectroscopy spectra, and mercury porosimetry. The results show that the grown MWCNTs microstructures are closely related to the porous structures and surface conditions of the carbon supports. By using bamboo as template, a porous carbon support with a large total pore volume, appropriate pore size, and abundant favorable surface functional groups is obtained, which is found to be an ideal support for growing the MWCNTs. Investigation of growth mechanism demonstrated that the combination of appropriate porous structures and surface conditions plays an essential role in catalyst distribution and MWCNTs growth.     

聚偏氟乙烯/碳纳米管纳米复合材料的制备和表征

采用超声波分散法制备了聚偏氟乙烯(PVDF)/多壁碳纳米管(MWCNT)复合材料。利用扫描电子显微镜、差示扫描量热法和傅立叶变换红外光谱等方法研究了复合材料的形态,考察了MWCNT用量对复合材料结晶行为和力学性能的影响。结果表明,通过超声处理,PVDF和MWCNTs之间产生了相互作用,复合体以球状的形式存在。MWCNTs的引入导致具有压电性的β相形成和屈服强度的提高。根据实验结果,对PVDF/MWCNT复合球体和β相的形成机理提出了可能的解释。     

Preparation, characterization and photocatalytic properties of CdS nanoparticles dotted on the surface of carbon nanotubes

Cadmium sulfide (CdS) nanoparticles dotted on the surface of multiwalled carbon nanotubes (MWCNTs) have been synthesized by the polyol method. The as-prepared materials were characterized by x-ray powder diffraction, transmission electron microscopy, scanning electron microscopy, and Brunauer-Emmett-Teller adsorption analysis. The results indicate that CdS nanoparticles with diameter of 5-8?nm are thickly and uniformly coated on the surface of the MWCNTs. The photodegradation of azo dye using these materials was evaluated by the degradation of Brilliant Red X-3B under visible light. The coated nanotubes show higher photocatalytic activity than both CdS alone and a CdS/activated carbon sample; in addition, there is an optimum content of MWCNTs. The presence of MWCNTs can also hamper the photocorrosion of CdS. The mechanism for the enhancement of MWCNTs on the adsorption and photocatalytic property of CdS is investigated for the first time.     

A comparison of melt and solution mixing on the dispersion of carbon nanotubes in a poly(vinylidene fluoride) matrix

Multi-walled carbon nanotube (MWCNT)/poly(vinylidene fluoride) (PVDF) composites were prepared by two frequently-used approaches, melt and solution mixing. The dispersion state of MWCNTs in the PVDF matrix was evaluated by rheological properties and confirmed by optical microscope, scanning electron microscope and transmission electron microscope images. It was found that the dispersion state of MWCNTs was dependent not only on the concentration of MWCNTs but also the mixing method. Specifically, solution mixing led to a much better dispersion of MWCNTs than melt mixing at low concentrations of MWCNTs (less than 5 wt.%), while the situation was reversed at higher concentrations. The dispersion mechanisms of MWCNTs for the two mixing methods were also discussed.     

On the Role of Stearic Acid on the Surface Properties of Carbon Nanotubes

In this article, modification of multiwalled carbon nanotubes (MWCNTs) with stearic acid (SA) was done using the wet chemical method. For this aim, MWCNTs were treated with high-concentrated nitric acid to create a functional group as a linkage between MWCNTs and SA. The modified MWCNTs with SA were examined by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), differential scanning calorimeter (DSC), and thermogravimetery analysis (TGA) instruments. The results of TGA and DSC indicate the deposition of about 4.3 wt% of SA on the surface of MWCNTs. This proves that the deposition of stearate with a medium diameter size of 20 nm on the surface of MWCNTs can be divided into physical and chemical adsorption. As well, the esterification occurs on the surface of functionalized MWCNTs and there is no SA unreacted on the surface of MWCNTs.     

Concise route to styryl-modified multi-walled carbon nanotubes for polystyrene matrix and enhanced mechanical properties and thermal stability of composite

Effective functionalization of multi-walled carbon nanotubes (MWCNTs) with styryl group was carried out via the esterification reaction of the carboxylate salt of carbon nanotubes and 4-vinylbenzyl chlorides in toluene. The functionalized MWCNTs were characterized through FTIR and Raman spectra to confirm the styryl groups covalently connected to the surface of MWCNTs. The weight loss of functionalized moieties determined by thermogravimetry-differential scanning calorimertry analysis is around 36%. Nanotube-reinforced polystyrene were fabricated by mixing functionalized MWCNTs and polystyrene. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images showed that the functionalized nanotubes had a better dispersion than the unfunctionalized MWCNTs in the matrix. Moreover, styryl-modified MWCNTs/PS nanocompsite presented obvious improvements in mechanical properties and thermal stability.     

聚丙烯/碳纳米管复合材料的结晶和介电行为

采用熔融共混制备了聚丙烯/碳纳米管复合材料(PP/MWCNTs)。利用场发射扫描电镜(FESEM)、差示扫描量热仪(DSC)、偏光显微镜(POM)、X射线衍射仪(XRD)及宽频介电仪(BDS)对复合体系的形态、非等温结晶行为、结晶结构以及介电行为进行了研究。结果表明,碳纳米管均匀分散于聚丙烯基体中,二者界面结合紧密;极少量碳纳米管的加入即对聚丙烯的结晶起显著的异相成核作用,促进聚丙烯α晶型的形成;此外,复合体系在导电逾渗阀值附近介电松弛行为显著加强。     

多壁碳纳米管改性InVO4光催化剂的制备及性能

以酸处理的多壁碳纳米管(MWCNTs)为载体,采用水热合成法制备了InVO4/MWCNTs光催化剂.利用场发射扫描电镜、X射线粉末衍射、BET-N2吸附、傅里叶红外光谱和紫外-可见漫反射吸收光谱等技术对样品的形貌、晶相组成、比表面积和吸光性能等物理性质进行了表征,并以气相的苯作为模型污染物,研究催化剂样品在可见光(λ>420 nm)照射下的光催化氧化能力.结果表明,InVO4颗粒均匀附着于MWCNTs,表面粒径约100 nm.与纯InVO4相比,InVO4/MWCNTs的比表面积和可见光吸收性能显著提高.在可见光照射下,InVO4/MWCNTs具有良好的光催化活性,反应4 h光催化降解苯的转化率和矿化率分别为41.0%和43.4%,其转化率分别是InVO4的1.5倍和掺氮TiO2的3倍,InVO4/MWCNTs光催化活性的提高与载体MWCNTs良好的电子传输特性有关.