Synthesis of Conjugated Polymer Nanoparticles in Non‐Aqueous Emulsions

Summary: A novel non‐aqueous emulsion system, consisting of cyclohexane as the continuous and acetonitrile as the dispersed phase, is described. Stabilization of the system can be achieved by using polyisoprene‐block‐poly(methyl methacrylate) copolymers as emulsifiers. The suitability of this system for performing water‐sensitive, catalytic, and oxidative polymerizations and polycondensations is demonstrated by the synthesis of poly(3,4‐ethylenedioxythiophene), poly(thiophene‐3‐yl‐acetic acid), and polyacetylene. In all cases spherical nanoparticles with diameters as small as 23 nm can be obtained.

     

Electrical Properties of Chain Microstructure Magnetic Emulsions in Magnetic Field

The work deals with the experimental study of the emulsion whose dispersion medium is a magnetic fluid while the disperse phase is formed by a glycerin-water mixture. It is demonstrated that under effect of a magnetic field chain aggregates form from the disperse phase drops. Such emulsion microstructure change affects its macroscopic properties. The emulsion dielectric permeability and specific electrical conductivity have been measured. It is demonstrated that under the effect of relatively weak external magnetic fields (～1 kA/m) the emulsion electrical parameters may change several fold. The work theoretically analyzes the discovered regularities of the emulsion electrical properties.     

Dehydration Efficiency of Water-in-Crude Oil Emulsions in Alternating Current Electrical Fields

The influence of several operational variables on the electrostatic separation of water-in-crude oil emulsions is investigated in a concentric cylinder rheometer equipped with an alternating current (AC) generator. Shear rate, temperature, emulsion water content, electric field strength, and application time are all found to play a role in the process. The droplet size distributions achieved across some of the experiments are acquired to give further support to the conclusions. Finally, the experimental results are compared to the theoretical expression for the electrocoalescence process and discussed.     

形状记忆聚偏氟乙烯/丙烯酸酯/碳纳米管纳米复合材料的导电及导热性能

利用聚偏氟乙烯（PVDF）微小结晶的物理交联点作用,制备了形状记忆性能优异的聚偏氟乙烯/丙烯酸酯聚合物（PVDF/ACM）共混材料,为提高其导电及导热性能,于其中引入了碳纳米管（CNT）,系统研究了PVDF/ACM/CNT三元体系纳米复合材料的导热及导电性能。 结果表明,碳纳米管在PVDF/ACM体系中分散均匀;在基本保持其形状记忆性能的前提下,碳纳米管的加入使材料导热性能及导电性能有较大程度的提高：质量分数为4%的CNT使材料25 ℃的电阻值降低至5000 Ω/square,导热系数提高至0.157 W/(m·K)。     

Phase Transitions in Emulsions Formed by Aqueous Emulsifier and its Action on Improving Mobility in Oil Recovery

Transition from oil-in-water (O/W) emulsions to water-in-oil (W/O) emulsions and its action on enhanced oil recovery was investigated by viscosity, morphology, and simulated flooding experiments. This transition can be realized by increasing the volume ratio of oil to water or decreasing the emulsifier concentration. At a mass concentration of 0.3 wt%, the self-developed emulsifier FJ-1 mainly forms O/W emulsions at a volume ratio (oil to water) of 1:1. The emulsions behave as O/W emulsions with a low viscosity when the volume ratio of oil to water is below 2:1. Above 2:1, increasing volume ratio leads to the O/W emulsions transferring into W/O emulsions with high viscosity. For example, at a volume fraction of 4:1, the viscosity of W/O emulsions reaches 229.1 mPa · s, and separated water can hardly be detected. Transition from O/W emulsions to W/O emulsions with high viscosity can also be realized by decreasing the concentration of emulsifier to 0.05 wt% or lower at a volume ratio of 1:1. These may be the critical factors leading to transition from O/W emulsions to W/O emulsions at core conditions. Simulated flooding experiments show that emulsifier fluids can act as an in situ mobility improver and make an improvement of oil recovery even by 20.4%. The results indicate that the water-in-crude-oil emulsions possess great potential in enhancing oil recovery.     

DC Electrical Conductivity of Some Oligoazomethines Doped with Nanotubes

Three aromatic oligoazomethines containing seven benzene rings each were synthesized. The terminal rings were substituted with different organic groups; namely, OH, H, and NO₂. Synthesis was carried out according to the literature by condensing the para-substituted benzaldehydes with benzidine to give the three rings compound, which is then condensed with terephthaldehyde to give the respective seven benzene rings oligomer. The oligomers were used to investigate the effects of molecular structure on the electronic structure, as well as electronic and electrical properties. DC electrical conductivity variation of oligoazomethines is studied in the temperature range 300–500 K after annealing for 24 h at 100°C and after doping with 25 and 50 wt% Multi Wall Nanotubes (MWNTs). An attempt is made to relate DC electrical conductivity and electronic properties to chain length, substituted groups and coplanarity. The different groups attached to the ends showed a small effect on conductivity of the different oligomers in the following order: electron donating > neutral > electron withdrawing groups. Oligoazomethines-MWNTs gave a value of (10^?4 Scm^?1) as the highest electrical conductivity at higher temperatures. DC electrical conductivity was interpreted using the band energy model. The narrow-gap activation energies noted suggest its application in formulation of photovoltaic panels.     

Jojoba Oil/Water Emulsions Stabilized by BSA and Egg Proteins: A Study Using Conductivity Technique

Stability of jojoba oil/water emulsion systems was investigated using the conductivity technique. Egg white, egg yolk, and bovine serum albumin (BSA) proteins were used as emulsifiers. Stability of above emulsions was investigated using several protein concentrations (0.05–0.50 mg/ml) and several oil volume fractions, OVF, (0.25; 0.50). It was concluded from the results that the investigated emulsions stability, when using BSA, was higher than when using egg white or egg yolk. In addition, emulsion stability did not show a strong dependence on OVF, except at the higher protein concentration of 5.0 mg/ml, where ES increased significantly with increasing OVF. Finally, emulsifier activity was found to increase with increasing OVF.     

DC Electrical Conductivity of Polymercaptobenzothiazole Disulfide Copper Complex

Polymercaptobenzothiazole disulfide-copper complex PMBTS-Cu has been synthesized by reacting 2-mercaptobenzothiazole disulfide with CuCl₂ in absolute ethanol and dimethyl sulfoxide (DMSO) under reflux for 24 h. PMBTS-Cu has been characterized by several techniques using electronic spectra, elemental analyses, FTIR spectroscopy, and its solubility has been investigated. DC electrical conductivity variation with temperature, in the range 300–500 K, after annealing for 24 h at 100°C, and doping with different ratios of I₂, is determined for comparison. Doping was done in two ways: by mixing and chemically. Activation energies were calculated and the results were interpreted using the band energy model. DC electrical conductivity of I₂doped PMBTS-Cu complex increased with increasing temperature due to the variation of the carrier concentration with temperature as in the case of semiconductors. PMBTS-Cu complex has a copper ion in its backbone and copper salt is known to be a good dopant. Thus, these materials are doped internally, so the doped polymer-Cu complex are only one or two orders of magnitude higher in DC electrical conductivity than the annealed state. However, the energy gap is very small, which suggests suitability in applications like photovoltaic cells.     

氯掺杂提高多壁碳纳米管的电导率

通过氯气吸附, 制备了掺氯多壁碳纳米管(Cl₂-MWNTs)复合材料, 在低温、高温和紫外光照射条件下掺氯, 紫外光照射下掺氯制备的复合材料电导率最高, 和未掺氯MWNTs相比, 电导率提高到原来的5倍以上. 用热重、红外吸收光谱、紫外-可见吸收光谱、拉曼光谱和X光电子能谱分析研究掺氯碳纳米管中氯和MWNTs间的相互作用, 结果表明: 掺氯后MWNTs中π电子向氯转移, 氯与MWNTs形成共轭体系, π电子的离域性增强, 提高了复合材料的电导率.     

一种军械油料快速检测方法研究

采用YX1154油料电导率测定仪研究了组分变化对45号变压器油和通用装备液压油两种油料电导率的影响,探索了电导率与传统测试指标的相关性.结果表明:油品电导率随防锈剂含量变化呈线性增加,并且与油料防锈性能测定结果一致.因此,该方法不仅可用于军用油料的生产质量检测和库存质量监控,而且可作为野战条件下评价油料性能的快速检测方法.     

Effect of Water Fraction on Rheological Properties of Waxy Crude Oil Emulsions

This article discusses the effect of water fraction on the rheological properties of waxy crude oil emulsions including gel point, yield stress, viscosity, and thixotropy. The experimental results reveal that the rheological behaviors of the w/o emulsion samples all intensify with the increase of water volume fraction within 60%. Of more significance is that a correlation for w/o emulsions between yield stress and water volume fraction is put forward with an average relative error of 6.75%. In addition, some mainstream viscosity prediction models of w/o emulsions are evaluated, and Elgibaly model is the best-fit for the emulsions in this study.     

NaCl对离子液体中电解精炼铝的影响

研究了添加NaCl对BMIC-AlCl3离子液体电导率及电解精炼铝的影响,分析了阴极电流效率、电流密度的变化,并通过扫描电镜和能谱分析研究了沉积层的形貌及成分。结果表明,添加NaCl可以提高电解液的电导率,阴极电流效率也可提高至82%～96%,但电流密度则有所降低;添加NaCl还可以改善电解精炼铝的沉积质量,使晶粒尺寸...     

Spatial‐Decomposition Analysis of Electrical Conductivity

Spatial decomposition is conducted for the electrical conductivity. The contribution per ion pair at a certain distance is identified in terms of a two‐body velocity time correlation function and is integrated over the whole distance of the ion pair to provide the cross‐correlation term of the conductivity. The spatial‐decomposition formula is an exact expression at any concentrations of ions and incorporates physically appealing pictures in the space domain into the theory of time correlation functions. Illustrative analyses are presented for 1m NaCl aqueous solution and the [C₄mim][NTf₂] ionic liquid. The contrast between the two systems is discussed for the time and spatial ranges of correlations, and it is shown that the ion‐pair contribution to the conductivity for the [C₄mim][NTf₂] system is not localized and extends beyond the first coordination shell of the cation‐anion pair.     

Novel Bio-Based Amphiphilic Ionic Liquids for the Efficient Demulsification of Heavy Crude Oil Emulsions

In the last few decades, there has been an increasing trend for the usage of natural products and their derivatives as green and renewable oil-filed chemicals. Use of these compounds or their derivatives contributes to reducing the use of traditional chemicals, and enhances green chemistry principles. Curcumin (CRC) is one of the most popular natural products and is widely available. The green character, antioxidant action, and low cost of CRC prompt its use in several applications. In the present study, Curcumin was used to synthesize two new amphiphilic ionic liquids (AILs) by reacting with 1,3-propanesultone or bromoacetic acid to produce corresponding sulfonic and carboxylic acids, CRC-PS and CRC-BA, respectively. Following this, the formed CRC-PS and CRC-BA were allowed to react with 12-(2-hydroxyethyl)-15-(4-nonylphenoxy)-3,6,9-trioxa-12-azapentadecane-1,14-diol (HNTA) to form corresponding AILs, GCP-IL and GRB-IL, respectively. The chemical structures, surface tension, interfacial tension, and relative solubility number (RSN) of the synthesized AILs were investigated. The efficiency of GCP-IL and GRB-IL to demulsify water in heavy crude oil (W/O) emulsions was also investigated, where we observed that both GCP-IL and GRB-IL served as high-efficiency demulsifiers and the efficiency increased with a decreased ratio of water in W/O emulsion. Moreover, the data showed an increased efficiency of these AILs with an increased concentration. Among the two AILs, under testing conditions, GCP-IL exhibited a higher efficiency, shorter demulsification time, and cleaner demulsified water.     

The Influence of Lateral Size and Oxidation of Graphene Oxide on Its Chemical Reduction and Electrical Conductivity of Reduced Graphene Oxide

The chemical reduction efficiencies of graphene oxide (GO) are critically important in achieving graphene-like properties in reduced graphene oxide (rGO). In this study, we assessed GO lateral size and its degree of oxidation effect on its chemical reduction efficiency in both suspension and film and the electrical conductivity of the corresponding rGO films. We show that while GO-reduction efficiency increases with the GO size of lower oxidation in suspension, the trend is opposite for film. FESEM, XRD, and Raman analyses reveal that the GO reduction efficiency in film is affected not only by GO size and degree of oxidation but also by its interlayer spacing (restacking) and the efficiency is tunable based on the use of mixed GO. Moreover, we show that the electrical conductivity of rGO films depends linearly on the C/O and Raman I_D/I_G ratio of rGO and not the lateral size of GO. In this study, an optimal chemical reduction was achieved using premixed large and small GO (L/SGO) at a ratio of 3:1 (w/w). Consequently, the highest electrical conductivity of 85,283 S/m was achieved out of all rGO films reported so far. We hope that our findings may help to pave the way for a simple and scalable method to fabricate tunable, electrically conductive rGO films for electronic applications.     

ET类分子导体3d轨道对晶体能带及导电性的影响

采用扩展休克尔 -紧束缚方法 (EHTB)研究了ET类分子导体 [ET =bis (ethylenedithio) tetrathiafulvalene]的能带 .讨论了硫原子 3d轨道对能带结构的影响 ,添加 3d轨道导致ET分子柱间的横向作用大为增强 ,并与纵向作用处于同一数量级 ,这一结论解释了晶体二维导电性的实验结果 .计算得到 (ET) 2 C3 H5SO3 ·H2 O ,(ET) 2 HgCl3 ·TCE两个晶体的带隙分别为0 5 79,0 .5 72eV ,与实验得到的导电激活能 0 .3 19,0 .3 0 8eV符合较好 .     

Electrical Conductivity of an Individual Polyaniline Nanotube Synthesized by a Self‐Assembly Method

Camphor sulfonic acid (CSA) doped polyaniline (PANI) nanotubes (175 nm in outer diameter and 120 nm in inner diameter) were synthesized successfully by a self‐assembly method. It is found that the room‐temperature conductivity of an individual PANI nanotube is 30.5 S · cm⁻¹; in particular, the intrinsic resistance of an individual nanotube (30 kΩ) is much smaller than the contact resistance of crossed nanotubes (500 kΩ).

A SEM image of two crossed PANI‐CSA nanotubes and the attached Pt electrodes.     

Effects of alkyl chain length on properties of 1-alkyl-3-methylimidazolium fluorohydrogenate ionic liquid crystals

A series of 1‐alkyl‐3‐methylimidazolium fluorohydrogenate salts (C_xMIm(FH)₂F, x=8, 10, 12, 14, 16, and 18) have been characterized by thermal analysis, polarized optical microscopy, IR spectroscopy, X‐ray diffraction, and anisotropic ionic conductivity measurements. Liquid crystalline mesophases with a smectic A interdigitated bilayer structure are observed from C₁₀ to C₁₈, showing a fan‐like or focal conic texture. The temperature range of the mesophase increases with the increase in the alkyl chain length (from 10.1 °C for C₁₀MIm(FH)₂F to 123.1 °C for C₁₈MIm(FH)₂F). The distance between the two layers in the smectic structure gradually increases with increasing alkyl chain length and decreases with increasing temperature. Conductivity parallel to the smectic layers is around 10 mS cm^?1 regardless of the alkyl chain length, whereas that perpendicular to the smectic layers decreases with increasing alkyl chain length because of the thicker insulating sheet with the longer alkyl chain.     

Facet‐Dependent Electrical Conductivity Properties of Silver Oxide Crystals

Ag₂O cubes, truncated octahedra, rhombic dodecahedra, and rhombicuboctahedra were synthesized in aqueous solution. Two tungsten probes were brought into contact with a single particle for electrical conductivity measurements. Strongly facet‐dependent electrical conductivity behaviors have been observed. The {111} faces are most conductive. The {100} faces are moderately conductive. The {110} faces are nearly non‐conductive. When electrodes contacted two different facets of a rhombicuboctahedron, asymmetrical I–V curves were obtained. The {111} and {110} combination gives the best I–V curve expected for a p‐n junction with current flowing in one direction through the crystal but not in the opposite direction. Density of states (DOS) plots for varying number of different lattice planes of Ag₂O match with the experimental results, suggesting that the {111} faces are most electrically conductive. The thicknesses of the thin surface layer responsible for the facet‐dependent properties of Ag₂O crystals have been determined.