单壁碳纳米管在胆酸类表面活性剂中的分散及手性碳管(6,5)的双水相分离方法

选用牛磺脱氧胆酸钠和脱氧胆酸钠等6种胆酸类表面活性剂,考察其对单壁碳纳米管(SWCNTs)的分散能力.紫外-可见-近红外吸收光谱测试结果表明,在超声功率为225 W,超声时间1 h的分散条件下,胆酸类表面活性剂均能对SWCNTs均匀分散,均可作为SWCNTs的分散剂.在相同条件下,质量分数为2%的牛磺脱氧胆酸钠对SWCNTs的分散能力最强,脱氧胆酸钠对SWCNTs的分散能力最弱.此外,还采用聚乙二醇/葡聚糖双水相系统对SWCNTs分散液进行了萃取分离,获得了纯度较高的手性SWCNTs(6,5).所筛选的SWCNTs分散剂及采用的双水相分离方法为单一手性SWCNTs的分离提供了一定的技术参考.     

盐类和温度对非离子型表面活性剂溶液粘度的影响

研究在各种盐类存在下,温度对非离子表面活性剂(OP类)溶液粘度的影响,发现相对粘度的对数值与1/T呈线性关系,从直线的斜率可得活化自由能ΔG′。由热力学关系式可计算粘性流体的活化焓ΔII′和活化熵ΔS′。用所得热力学函数对胶束型态的转化进行了讨论。     

表面活性剂对碳纳米管分散性及其湿法纺丝纤维性能的影响

碳纳米管(CNT)纤维因具有低密度、高强度以及高电导率等特性受到广泛关注。在湿法纺丝技术制备CNT纤维的工艺中,探究纺丝分散液和纺丝条件对CNT纤维性能的影响具有重要意义。本文研究了十二烷基硫酸钠(SDS)、十六烷基三甲基溴化铵(CTAB)、胆酸钠(SC)、牛磺脱氧胆酸钠(STDC)等表面活性剂对CNT纤维制备及性能的影响。通过拉曼光谱、紫外可见光谱、偏光显微镜、旋转流变仪、扫描电镜等方法对材料进行表征,以拉伸测试和“四探针”法对材料性能进行测试。结果表明,单壁碳纳米管(SWNTs)在表面活性剂的2(wt)%水溶液中的分散能力顺序依次为STDC> SC> CTAB> SDS;SDS或CTAB修饰的SWNTs分散液无法纺制纤维,SC和STDC修饰的SWNTs分散液具有良好的可纺性。其中以STDC作表面活性剂制备的CNT纤维性能最好,其断裂强度为160MPa,杨氏模量为12.3GPa,电导率为2300S/cm。     

正负离子表面活性剂/离子液体双水相性质研究

本文把短链离子液体(IL)四氟硼酸1-乙基-3-甲基咪唑鎓[C2mim]BF4引入正负离子表面活性剂十二烷基硫酸钠(SDS)和十二烷基三甲基溴化铵(DTAB)双水相体系(SDS/DTAB/H2O)中,研究了IL对双水相相图及相分离体系性质的影响。结果表明,[C2mim]BF4的阳离子性质是影响阴离子表面活性剂过量区域性质的主要因素,IL通过静电作用、氢键作用等改变体系中聚集体的形貌,最终导致阴离子双水相(ATPSa)的消失。IL的阴离子对阳离子双水相(ATPSc)区域性质起着决定作用;IL的盐效应引起的对表面活性剂混合胶束扩散双电层的压缩作用,不但促进胶团的形成,缩短了形成稳定胶团所需要的时间,加快了双水相的相分离速度,而且也造成了形成ATPSc所需DTAB含量的提高。IL的引入改变了ATPSc上、下相表面活性剂的组成及含量,使富含表面活性剂的上相中阳离子表面活性剂含量更高,进而提高了双水相的萃取性能,其上相对甲基橙的萃取效率可高达96.67%。     

可聚合非离子型表面活性剂的合成及其性能

由甲苯二异氰酸酯、丙烯醇和不同分子量的聚乙烯醇合成了3种可聚合非离子表面活性剂（Ⅱ-PEG400、Ⅱ-PEG1000和Ⅱ-PEG2000）,用FT-IR对分子结构进行了表征。 结果表明,随聚乙烯醇分子量的增加,非离子表面活性剂的电导率显著增加、表面张力由36.28 mN/m降低至31.30 mN/m、浊点由39.6 ℃增加至58.9 ℃,对丙烯酸丁酯(BA)、甲基丙烯酸甲酯(MMA)和甲基丙烯酸丁酯(BMA)的乳化能力均优于常用乳化剂OP-10,以AIBN作引发剂在70 ℃下既能均聚又可与丙烯酸酯进行共聚反应。     

不同乙氧基链段的非离子型表面活性剂在电极表面的电化学行为

蛋白质是生命的基础,研究氧化还原蛋白质的直接电化学不仅对模拟生物体系电子传递机理具有重要意义,而且为传感器的构筑提供了理论基础。遗憾的是,蛋白的直接电化学在裸电极上很难实现,许多研究者通过在电极上引入表面活性剂来克服该缺点.值得思考的是为什么在表面活性剂存在下,蛋白与电极之间才能实现直接电化学?甚至促进蛋白与电极之间的电子转移速率?因此研究表面活性剂在电极表面上的形态非常必要.我们主要讨论不同乙氧基单元的表面活性剂与蛋白之间在玻碳电极上的电子转移过程.结果表明不同表面活性剂提供给蛋白不同的微环境.当表面活性剂的乙氧基链长达到最佳值时,该修饰电极能固载更多的蛋白.我们利用紫外光谱法检测蛋白在固载过程中是否变性,同时也对所构筑的修饰电极的电催化性能进行表征.     

非离子表面活性剂测定方法的研究进展

综述了非离子表面活性剂测定方法(包括色谱法、质谱法、液相色谱-质谱法、气相色谱-质谱法、电化学法、红外光谱法、化学发光法和分光光度法等)的研究进展(引用文献82篇)。     

非离子表面活性剂Tween 20的胶束电动毛细管色谱分离

采用非离子表面活性剂Tween20胶束电动毛细管色谱法(MEKC),成功分离了莨菪亭、芸香苷和七叶亭3种多酚化合物。分离缓冲液为50mmol/LTween20 60mmol/LNa2B4O7(pH9.4)溶液,并用示差分光光度法测定Tween20与芸香苷和七叶亭的反应平衡常数和结合比,反应平衡常数分别为4.53×105和2.23×105(L/mol)2,结合数均为n=2。结果表明:Tween20-MEKC分离3种多酚是基于多酚与Tween20结合作用和电泳淌度的差异。     

非离子表面活性剂的结构对络合物吸收光谱的影响

本文用分光光度和核磁共振两种实验方法研究非离子表面活性剂(记作n-Sf)胶束对漂蓝6B(ECAB)及其金属络合物的增溶增敏作用。n-Sf对金属络合物的增溶增敏作用发生在胶束的极性部分与非极性部分的交界处,故n-Sf分子中的烷基链与聚氧乙烯链是否直接相联,会影响到金属-ECAB络合物的吸收光谱形状、λ_(max)和ε值。n-Sf胶束增溶ECAB,会抑制ECAB的酸式离解。     

Dispersion and orientation of single-walled carbon nanotubes in a chromonic liquid crystal

A post-synthesis alignment of individual single-walled carbon nanotubes (SWCNTs) is desirable for translating their unique anisotropic properties to a macroscopic scale. Here, we demonstrate excellent dispersion, orientation and concomitant-polarised photoluminescence of SWCNTs in a nematic chromonic liquid crystal. The methods to obtain stable suspension are described, and order parameters of the liquid crystal matrix and of the nanotubes are measured independently.     

Enhanced dispersion stability of supramolecular complexes of single-walled carbon nanotubes with fluorene-based conjugated polymers

Supramolecular complexes of single-walled carbon nanotubes (SWNTs) with poly(9,9-didodecylfluorene-2,7-diyl) (PF) derivatives were prepared using a solution dispersion process. A series of novel conjugated PF polymers with carboxyl or hydroxyl end groups at both ends were synthesized by the Yamamoto-type coupling of 2,7-dibromo-9,9-didodecylfluorene using Ni(COD)₂ as a catalyst, and further end-capped with either 4-bromobenzoic acid or 4-bromobenzyl alcohol to obtain the end-functionalized PF with different terminal groups. An α-monocarboxy-ω-mono-methoxy poly(ethylene glycol) was connected to both ends of the PF-containing hydroxyl end groups to produce triblock copolymers of poly(ethylene glycol)-b-polyfluorene-b-poly(ethylene glycol) (PEO-b-PF-b-PEO). These SWNTs were completely wrapped with the conjugated polymers through π–π interactions, which enhanced the solubility of the SWNT complexes in organic media, and prevented the aggregation of the polymer–SWNT complexes into large bundles. This indicates that the dispersion stability of SWNTs is enhanced by the addition of the conjugated polymers.     

单壁碳纳米管固相萃取-气相色谱-质谱联用法测定茶油中6种邻苯二甲酸酯

建立了单壁碳纳米管（SWCNTs）为吸附剂的固相萃取净化-气相色谱-质谱检测茶油中6种邻苯二甲酸酯（PAEs）的分析方法。样品经正己烷稀释,玻璃SWCNTs SPE小柱净化,GC-MS选择离子监测（SIM）模式测定,外标法定量。对正己烷的稀释体积、吸附材料的类型、SWCNTs用量、淋洗液用量、洗脱溶剂类型和体积等影响萃取效率的条件进行了优化,得到的最优萃取条件为：正己烷稀释体积为5 mL,SWCNTs用量为0.6 g,淋洗液为20 mL正己烷,洗脱溶剂为5 mL甲苯。6种PAEs在0.05~1.0 mg/L范围内线性关系良好,相关系数（r）均大于0.9999;在0.05~1.0 mg/kg添加范围内,6种目标物的平均回收率为86.4%~111.7%,相对标准偏差为4.2%~10.4%。该方法准确、快速,可满足茶油中6种邻苯二甲酸酯的检测需要。     

High yield fabrication of semiconducting thin-film field-effect transistors based on chemically functionalized single-walled carbon nanotubes

Here we report a simple and scalable method to fabricate high performance thin-film field-effect transistors(FETs) with high yield based on chemically functionalized single-walled carbon nanotubes(SWNTs) by organic radical initiators.The UV-Vis-NIR spectra,Raman spectra and electrical characterization demonstrated that metallic species in CoMoCat 65 and HiPco SWNTs could be effectively eliminated after reaction with some organic radical initiators.The effects of the substrate properties on the electrical pr...     

Enhanced separation of Compound Xueshuantong capsule using functionalized carbon nanotubes with cationic surfactant solutions in MEEKC

A novel additive of multi‐walled carbon nanotubes (MWNTs) dispersed with cationic surfactants or mixed cationic/anionic surfactants was used for MEEKC separation of eight phenolic compounds, four glycosides, and one phenanthraquinone. In this context, several parameters affecting MEEKC separation were studied, including the dispersion agents of MWNTs, MWNTs content, oil type, SDS concentration, and the type and concentration of cosurfactant. Compared with conventional MEEKC, the addition of all types of MWNTs dispersions using single or mixed cationic surfactant solutions in running buffers was especially useful for improving the separation of solutes tested, as they influenced the partitioning between the oil droplets and aqueous phase due to the exceptional electrical properties and large surface areas of MWNTs. Use of cationic surfactant‐coated MWNTs (6.4 μg/mL) as the additive in a microemulsion buffer (0.5% octanol, 2.8% SDS, 5.8% isopropanol, and 5 mM borate buffer) yielded complete resolution of 13 analytes. The proposed method has been successfully applied for the detection and quantification of the studied compounds in a complex matrix sample (Compound Xueshuantong capsule).     

Aqueous two-phase system of an anionic gemini surfactant and a cationic conventional surfactant mixture

The aqueous two-phase system formed by the mixture of dodecyltrimethylammonium bromide (DTAB) with a gemini surfactant O,O′-bis(sodium 2-lauricate)-p-benzenediol (C₁₁pPHCNa) has been studied. Two two-phase regions were observed, one was a wide region in the cationic surfactant-rich side and the other in the vicinity of R = 1:1, where R is the mixing mole ratio of DTAB to C₁₁pPHCNa in global solution. Multi-lamellar vesicles are formed in the concentrated upper phase of cationic surfactant-rich systems and spherical aggregates in the concentrated bottom phase at R = 1:1. The microstructure of the solution and the phase behavior of the aqueous two-phase system strongly depended on the total concentration and the composition of the system.     

Dielectrophoretic manipulation of fluorescing single-walled carbon nanotubes

We investigate the behavior of fluorescing single-walled carbon nanotubes (SWCNTs) under dielectrophoretic conditions and demonstrate their collection with fluorescence microscopy. SWCNTs are dispersed in water with the aid of a nonionic surfactant, Triton X-100, and labeled through noncovalent binding with the dye 3,3'-dihexyloxacarbocyanine iodide (diOC(6)). The chromophore's affinity to the SWCNTs is due to pi-stacking interactions. Carbon nanotube (CNT) localization is clearly identified on the fluorescence images, showing that the nanotubes concentrate between the electrodes and align along the electric field lines.     

Organophosphorus pesticides detection using acetylcholinesterase biosensor based on gold nanoparticles constructed by electroless plating on vertical nitrogen-doped single-walled carbon nanotubes

An acetylcholinesterase (AChE) biosensor was constructed based on gold nanoparticles (AuNPs) using electroless plating on vertical nitrogen-doped single-walled carbon nanotubes (VNSWCNTs) for detecting organophosphorus pesticides (OPs). AChE was immobilised on AuNPs via Au–S bonding, and VNSWCNTs were produced by spontaneous chemical adsorption of NSWCNTs on gold electrode, also via Au–S bonding. This modified electrode exhibited excellent electron transfer capacity due to the synergy between AuNPs and VNSWCNTs. The developed biosensor showed good linear relations at concentrations of 10^?5 – 1 ppb, and the detection limits were 3.04 × 10^?6 ppb for methyl parathion, 1.96 × 10^?6 ppb for malathion and 2.06 × 10^?6 ppb for chlorpyrifos, respectively. The AChE biosensor revealed satisfactory stability, excellent sensitivity and good repeatability. These results suggest that this biosensor has good application prospects and can function as a sensitive device in OPs analysis.