十六烷基三甲基溴化铵修饰的单壁碳纳米管和寡核苷酸的结合及细胞毒性(英文)

应用十六烷基三甲基溴化铵(CTAB)作为表面活性剂修饰单壁碳纳米管,研究CTAB修饰后的单壁碳纳米管的分散情况和表面电荷情况;观察在场发射扫描电子显微镜和透射电子显微镜下的形貌,同时还研究CTAB修饰后的单壁碳纳米管与小干扰RNA结合的最佳浓度配比,以及CTAB功能修饰后的碳纳米管对培养的人脐静脉内皮细胞的毒性。结果表明:CTAB修饰后的单壁碳纳米管分散良好,CTAB吸附到单根或成束的碳纳米管管壁上,表面带正电荷;与带负电荷的寡核苷酸分子小干扰RNA可以结合,并且CTAB-SWNT与小干扰RNA结合比例达到1:1.5到1:2之间时基本饱和;缺乏CTAB的单壁碳纳米管不能结合小干扰RNA;没有分散的单壁碳纳米管具有更大的细胞毒性,CTAB可以改善SWNTs的分散性,从而减轻单壁碳纳米管的细胞毒性。     

单链DNA/表面活性剂与单壁碳纳米管的亲合力及荧光检测性能(英文)

研制一种基于单链DNA与单壁碳纳米管荧光变化的新型荧光探针用于表面活性剂物质的检测方法。考察了温度对探针稳定性的影响,通过观察实时荧光光谱变化来评估单壁碳纳米管与5种常见表面活性剂物质的亲和性,观察镁离子及pH对探针检测表面活性物质的影响,通过观察荧光发射光谱变化来考察加入不同浓度表面活性物质曲拉通X-100后荧光探针的荧光恢复情况。结果表明,在5~80°C的温度范围内,探针十分稳定;单壁碳纳米管与5种常见表面活性物质的亲和力由强至弱依次为曲拉通X-100、十二烷基苯磺酸钠、吐温-20、吐温-80、十二烷硫酸钠;荧光探针检测的最佳Mg2+浓度为10mmol/L,pH为7.4;当加入不同浓度的表面活性剂物质曲拉通X-100时,探针体系的荧光逐渐得到恢复。     

多壁碳纳米管/氧化铕复合材料的制备

利用混合酸对催化裂解法制备的多壁碳纳米管进行纯化,然后先后用氨水和柠檬酸对纯化后的多壁碳纳米管进行修饰,最后利用共沉淀法和热处理制各了碳纳米管氧化铕复合材料,并使用红外光谱、X-衍射仪(XRD)、扫描电镜(SEM)研究了碳纳米管及氧化铕复合材料的结构和形貌.光谱结果表明:经过混合酸纯化后,碳纳米管表面拥有丰富的羟基和羧基等官能团,而且能够在纯化后的多壁碳纳米管表面引入氨基和柠檬酸分子.电子显微图像显示,在450℃下热处理,获得了多壁碳纳米管/氧化铕纳米线复合材料;在750℃下热处理,获得了多壁碳纳米管/纳米氧化铕复合材料.     

多壁碳纳米管/氧化铁复合粉体的制备

利用混合酸对催化裂解法制备的碳纳米管进行纯化,然后先后用氨水和柠檬酸对纯化后的多壁碳纳米管进行修饰,最后利用共沉淀法制备碳纳米管氧化铁前驱体,并于450℃下热处理2 h.通过X射线衍射仪、扫描电镜和透射电镜表征了复合粉体的结构和形貌.光谱结果表明:经过混合酸纯化后,碳纳米管表面拥有丰富的羟基和羧基等官能团,而且能够在纯化后的多壁碳纳米管表面引入氨基和柠檬酸分子.电子显微图像显示碳纳米管表面被α-Fe2O3纳米颗粒和纳米棒修饰.     

聚多巴胺改性碳纳米管增强羧基丁腈橡胶动态力学性能的研究

目的 探究改性多壁碳纳米管（MWCNTs）在羧基丁腈橡胶（XNBR）中的分散性、增强橡胶基体动态力学性能及其作用机理。方法 采用多巴胺自聚合兼物理修饰的技术对MWCNTs进行表面改性处理，以增加其表面极性基团，提高其与XNBR基体的兼容性，并制备了聚多巴胺改性碳纳米管（MWCNTs-P）。采用红外光谱仪和X射线光电子能谱仪分析了改性多壁碳纳米管的表面化学状态，使用透射电子显微镜（TEM）探索了改性碳纳米管的结构演变。使用动态力学分析仪（DMA）研究了改性碳纳米管填料网络对XNBR基体的增强效果，结合复合材料断面的扫描电镜（SEM）和透射电镜（TEM），探索了MWCNTs-P填料增强XNBR动态力学性能的作用机理。结果 调控多巴胺反应浓度实现了MWCNTs-P填料表面物理包覆层厚度从2 nm增加到4 nm。动态力学性能测试表明，MWCNTs-P填料提高了复合材料老化前后的动态力学性能。SEM测试发现，MWCNTs-1.0P-2.0wt%复合材料在老化试验后断面存在的孔洞最浅。TEM测试发现，MWCNTs-1.0P填料在XNBR基体中有更好的分散性。结论 聚多巴胺改性多壁碳纳米提高了其在羧基丁腈橡胶基体中的分散性，从而增强了复合材料老化前后的动态力学性能。     

表面活性剂对Ni-纳米TiO2复合镀层硬度的影响

针对镍镀层硬度较低,限制了其应用范围的实际,采用纳米复合电镀,提高电镀镍层的机械性能.由于纳米微粒极易团聚,影响了复合镀层的性能.进行了Ni-纳米TiO2复合电镀的表面活性剂筛选,并优选出分散效果较好的阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)和非离子表面活性剂吐温80进行均匀设计和正交回归设计的复配优化来研究其对复合镀层的影响,采用SEM观察镀层表面形貌.通过分析试验结果可知:两者复合的效果较单一使用的效果更好,在镀液中添加0.074g/L的CTAB和0.047g/L吐温80时,得到的复合镀层组织均匀细致,硬度达到最大值621.6HV.     

CTAB对于介孔羟基磷灰石形貌和孔结构的影响（英文）

以阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)为模板剂,采用水热法合成介孔羟基磷灰石,并利用不同检测手段对其物相、形貌和孔结构进行表征。结果表明,合成物是高度结晶的羟基磷灰石相。表面活性剂对催化剂晶粒的形貌影响较小,但明显影响孔结构的形成。无表面活性剂存在时晶粒的比表面积较小(≤33 m2/g),,通过TEM无法观察到明显的孔结构。而对于有表面活性剂存在时合成的样品,可以看到许多孔径大小为2~7 nm的开孔,不均匀地分布在羟基磷灰石纳米棒的表面。氮气吸附-脱附实验得到的均为吸附IV型等温线,并伴有明显的滞后环,证实了介孔结构的存在。当CTAB与羟基磷灰石的摩尔比为1:2时,样品的比表面积与孔容最大,其比表面积为97.1 m2/g,孔容为0.466 cm3/g。     

表面活性剂对镀Ti金刚石-Ni复合电沉积行为的影响

研究了阴离子表面活性剂十二烷基硫酸钠(SDS,sodium dodecyl sulfate)和阳离子表面活性剂十六烷基三甲基溴化铵(CTAB,cetyl trimethyl ammonium bromide)对镀Ti金刚石-Ni复合电沉积的影响,并结合循环伏安、交流阻抗等电化学方法研究了镀Ti金刚石-Ni镀液中Ni电沉积过程。结果表明:与未镀覆金刚石相比,镀Ti金刚石与Ni层浸润性得到提高。浓度为0.05 g/L的SDS对Ni电结晶过程有抑制作用,而浓度为0.05 g/L的CTAB能促进Ni~(2+)离子转移并加快Ni的电沉积过程。SDS和CTAB都能促进电沉积过程中氢气的析出并细化Ni镀层,同时减少镀层针孔和凹痕。     

多壁碳纳米管/壳聚糖复合材料的制备及电催化性能

采用混酸法制备羧基化多壁碳纳米管以及采用超声凝聚法制备壳聚糖纳米粒子,再通过静电自组装的方法制备碳纳米管/壳聚糖(相对分子质量(Mr)不小于5万和不小于10万)、碳纳米管/高密度壳聚糖、碳纳米管/羧化壳聚糖、多壁碳纳米管/壳聚糖盐酸盐复合材料。通过SEM、HRTEM及XRD对产品进行微观结构分析,利用循环伏安法对H2O2在碳纳米管/壳聚糖修饰电极上的电化学行为进行研究。结果表明:壳聚糖盐酸盐对碳纳米管具有较好的包覆效果,包覆层厚度约为3.5nm,静置12h后具有良好的溶液分散性;碳纳米管/壳聚糖盐酸盐修饰玻碳电极改善了H2O2的氧化还原电流,同时还降低了H2O2的氧化还原的过电势,对其电化学催化性能具有良好的促进作用。     

表面活性剂对微波水热合成磷化钴的影响

以氯化钴和黄磷为主要原料，以十六烷基三甲基溴化铵（CTAB）为结构导向剂，采用微波水热法制备了一维磷化钴（Co2P）纳米线。研究了表面活性剂及其加入量对合成Co2P晶相和形貌的影响，及其电化学性能。利用X-射线衍射仪（XRD）、扫描电子显微镜（SEM）和透射电子显微镜（TEM）对产物的物相和显微结构进行表征。结果表明：引入表面活性剂均可以使试样中生成一维Co2P纳米结构，添加CTAB的试样中生成了大量的Co2P纳米线，其直径约为50~200 nm，产率和长径比均随着CTAB加入量的增加而增加。电化学性能结果表明，Co2P纳米线具有赝电容特性，循环稳定性较好，1000次循环后比电容保持率为68%。     

Dielectrophoretic assembly of semiconducting single-walled carbon nanotube transistor

A novel burning technique for making a semiconducting single-walled carbon nanotubes (SWNTs) transistor assembled by the dielectrophoretic force was suggested. The fabrication process consisted of two steps. First, to align and attach a bundle of SWNTs between the source and drain, the alternating (AC) voltage was applied to the electrodes. When a bundle of SWNTs was connected between two electrodes, some of metallic nanotubes and semi-conducing nanotubes existed together. The second step is to burn the metallic SWNTS by applying the voltage between two electrodes. With increasing the voltage, more current flowed through the metallic SWNTs, thus, the metallic SWNTs burnt earlier than the semiconducting one. This technique enables to obtain only semi-conducting SWNTs connection in the transistor. Through the I—V characteristic graph, the moment of metallic SWNTs burning and the characteristic of semi-conducing nanotubes were verified.     

Dielectrophoretic assembly of semiconducting single-walled carbon nanotube transistor

A novel burning technique for making a semiconducting single-walled carbon nanotubes (SWNTs) transistor assembled by the dielectrophoretic force was suggested. The fabrication process consisted of two steps. First, to align and attach a bundle of SWNTs between the source and drain, the alternating (AC) voltage was applied to the electrodes. When a bundle of SWNTs was connected between two electrodes, some of metallic nanotubes and semi-conducing nanotubes existed together. The second step is to burn the metallic SWNTS by applying the voltage between two electrodes. With increasing the voltage, more current flowed through the metallic SWNTs, thus, the metallic SWNTs burnt earlier than the semiconducting one. This technique enables to obtain only semi-conducting SWNTs connection in the transistor. Through the I-V characteristic graph, the moment of metallic SWNTs burning and the characteristic of semi-conducing nanotubes were verified.     

The influence of SDS and CTAB surfactants on the surface morphology and surface topography of electroless Ni–P deposits

The effect of surfactants sodium dodecyl sulphate (SDS) and cetyltrimethyl ammonium bromide (CTAB) on the surface roughness, surface morphology and surface topography of electroless nickel (EN)–phosphorus surface protective coating obtained from an alkaline bath is presented in this paper. In this study the influence of surfactant concentrations on the surface roughness of coated samples were investigated. It was observed that the surface roughness, surface morphology and surface topography of Ni–P coating were clearly influenced by the addition of surfactants SDS and CTAB. EN deposits with addition of surfactant SDS and CTAB at a concentration of 0.6 g/l produce a smooth surface and the average roughness (R_a) value is 1.715 μm for SDS and 1.607 μm for CTAB which is less than the R_a value of EN deposit without surfactant addition (1.885 μm). The mean average roughness (R_a) value with addition of surfactant is 1.796 μm.EN deposit with addition of surfactants consists of a significant fraction of particles of nickel. In the presence of SDS, fine nickel particles have dispersed uniformly on the substrate surface resulting in smoother surface finish of the deposited layers. In the presence of CTAB, at lower concentrations (upto 0.6 g/l) coalescence of nickel particles have been deposited on the substrate surface and at the higher concentration (above 0.6 g/l) uniformly improved surface finish of the deposited layer is resulted. The complete experimental details, results obtained and their analysis are presented in this paper.     

Study of interactions in carbon nanotubes systems by using Raman and SERS spectroscopy

We present results obtained on carbon nanotube systems by means of Raman scattering and surface enhanced Raman scattering (SERS). Such systems consist of single-walled nanotubes (SWNTs), multi-walled nanotubes (MWNTs), or polymer/nanotubes composites. In particular, we have focused our studies on the interactions taking place in these compounds which lead to an upshift of the radial breathing mode (RBM) in the case of SWNTs, either when they are arranged in bundles or embedded in polymers. Similar calculations has allowed us to interpret the low frequency Raman modes observed in purified MWNTs. We show that they come from the RBM of individual tubes. From intensity calculations performed to simulate Raman spectra, we demonstrate the importance of two experimental parameters, namely the diameter of internal tubes and the number of shells which constitute the MWNTs, such parameters being extracted experimentally from high resolution transmission electron microscopy images.     

Purification and length separation of single-walled carbon nanotubes using chromatographic method

Purification and length separation of oxidatively shortened single-walled carbon nanotubes (SWNTs) were achieved by size exclusion chromatography (SEC) without assistant reagents for dispersion. Almost all the carbonaceous impurities, such as carbonaceous particles, graphene fragments, can be removed from the oxidatively shortened SWNTs materials. The short carbon nanotubes were separated into fractions according to nanotube lengths, and the length distribution of each fraction was relatively narrow.     

Megahertz magneto-dielectric properties of nanosized NiZnCo ferrite from CTAB-assisted hydrothermal process

A simple hydrothermal route with cetyltrimethyl ammonium bromide (CTAB) was proposed for directly synthesizing single-crystalline NiZn ferrite at 160 °C. X-ray diffraction patterns and micrographs indicate that products consist of spinel ferrite nanogranulars. The dielectric constant of NiZnCo ferrite is about 11 and the imaginary part of complex permittivity is 1.3. The saturation magnetization (M_s) of NiZn ferrite improves from 0.041 to 0.074 A·m²/g for Ni_0.49Zn_0.5Co_0.01Fe_1.98O₄. The dielectric contant of NiZn ferrite increases from 7 to 11 with a cobalt stoichiometry of 0.01. The real part μ′ of complex permeability for NiZnCo ferrite reaches 3 at 1 GHz. The imaginary part μ′′ of NiZnCo ferrite has a value higher than 1.2 within 0.7?3.0 GHz. Through the incorporation of the magnetic fillers, the low dielectric constant of the composites may meet the requirements of impedance matching to achieve the maximal absorption of the electromagnetic energy in megahertz frequency range.     

溶胶-凝胶法有序介孔氧化硅薄膜的蒸发诱导自组装制备

以表面活性剂CTAB为模板,将TEOS与APTES以一定的比例混合,自组装共聚合成出有序介孔氧化硅薄膜,并采用XRD、FTIR、TEM、TGA及N2吸附等手段对PMO薄膜进行了表征,结果表明,当APTES/(TEOS APTES)比例为0.10时,介孔薄膜有序性最好,平均孔径为2.16 nm,比表面积达到1060 m2/g,孔容积达到0.76 cm3/g.     

SERS,FT-IR and photoluminescence studies on single-walled carbon nanotubes/conducting polymers composites

Surface-enhanced Raman scattering (SERS), Fourier transform infrared (FT-IR) and photoluminescence (PL) spectroscopies were used to investigate composites based on single-walled carbon nanotubes (SWNTs) and different conducting polymers like polyaniline (PANI), poly-paraphenylene vinylene (PPV) and poly 3-hexylthiophene (3-PHT). In the case of SWNTs/PANI, different composites are obtained by adding dispersed SWNTs powder to the polymer solutions and by chemical polymerization of aniline in presence of SWNTs. The difference originates in the irreversible chemical transformation of SWNTs in the polymerization medium. The synthesis medium used for the preparation of PANI transforms SWNTs in fragments of shorter length like closed-shell fullerenes. This explains the similarity of SERS and FT-IR spectra of the composites PANI/SWNTs and PANI/C₆₀, chemically synthesized. Electrochemical polymerization of aniline in an HCl solution on a SWNT film leads to a covalent functionalization of SWNTs with PANI. In this case, Raman scattering data suggest an additional nanotubes roping with PANI as a binding agent. A post treatment with the NH₄OH solution of polymer-functionalized SWNTs involves an internal redox reaction between PANI and carbon nanotubes. As a result, the polymer chain undergoes a transition from the semi-oxidized state into a reduced one. In the case of PPV and 3-PHT, the effect of the concentration of SWNTs on the photoluminescence properties will be described and compared, as probes of interaction.     

Inhibitory effect of cetyltrimethyl ammonium bromide on the corrosion of 904L stainless steel in LiBr solution

The inhibitory influence of cetyltrimethyl ammonium bromide (CTAB) on 904L stainless steel (SS) in LiBr solution was investigated by potentiodynamic polarisation, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy techniques. The results showed that the inhibition efficiency of CTAB increases with the increasing concentration. The adsorption of CTAB on 904L SS surface obeys the Langmuir isotherm equation. The data reveal that the CTAB was of mixed-type inhibitor. The thermodynamic parameters for the corrosion of 904L SS in 1.0?M LiBr solution were calculated and discussed. The EIS data are in agreement with potentiodynamic polarisation measurements.