共查询到20条相似文献,搜索用时 15 毫秒
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Yan An GAO Zhong Ni WANG Jin ZHANG Wan Guo HOU Gan Zuo LI* Bu Xing HAN* Feng Feng Lü Gao Yong ZHANG Key Laboratory of Colloid Interface Chemistry 《中国化学快报》2005,16(7):963-966
The surfactant TX-100 can be dissolved in ionic liquid bmimPF6 and decrease the surface tension of 1-buty1-3-methylimidazolium hexafluorophosphate (bmimPF6) solutions. Here, we confirmed that in this new system, the pure solvents need rearrangement at the air-wate rinterface at the initial stage. The dynamic surface tension (DST) study shows that at the initial adsorption stage, the adsorption model of surfactant accords with the diffusion-controlled adsorption mechanism, and the dilute ionic liquids solutions is further close to the diffusion-controlled adsorption. 相似文献
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Xiaolin Wang Qiao Yang Yixue Cao Junhan Zhou Haibin Hao Yuanyuan Liang Prof. Dr. Jingcheng Hao 《化学:亚洲杂志》2016,11(5):722-729
Green and environmentally friendly ionogels formed by a sugar surfactant were prepared in two kinds of imidazolium‐based ionic liquids. The phase transition from ribbon structures to lamellar structures induced by temperature and the transition mechanism were investigated in detail by means of freeze‐fracture TEM and field‐emission SEM observations, as well as small‐angle X‐ray scattering measurements. The rheological properties and tribological properties of two kinds of ionogels were systematically investigated. The difference in the lubricating properties and antiwear capability can be explained well by the mechanical and viscoelastic properties, as well as the different microstructures of samples destroyed by shear forces. This work provides a better understanding of the relationship between the structures, rheological properties, and tribological properties of ionogels. 相似文献
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Jose Manuel Vicent‐Luna Dr. David Dubbeldam Dr. Paula Gómez‐Álvarez Prof. Sofia Calero 《Chemphyschem》2016,17(3):380-386
Aqueous solutions of ionic liquids are of special interest, due to the distinctive properties of ionic liquids, in particular, their amphiphilic character. A better understanding of the structure–property relationships of such systems is hence desirable. One of the crucial molecular‐level interactions that influences the macroscopic behavior is hydrogen bonding. In this work, we conduct molecular dynamics simulations to investigate the effects of ionic liquids on the hydrogen‐bond network of water in dilute aqueous solutions of ionic liquids with various combinations of cations and anions. Calculations are performed for imidazolium‐based cations with alkyl chains of different lengths and for a variety of anions, namely, [Br]?, [NO3]?, [SCN]?, [BF4]?, [PF6]?, and [Tf2N]?. The structure of water and the water–ionic liquid interactions involved in the formation of a heterogeneous network are analyzed by using radial distribution functions and hydrogen‐bond statistics. To this end, we employ the geometric criterion of the hydrogen‐bond definition and it is shown that the structure of water is sensitive to the amount of ionic liquid and to the anion type. In particular, [SCN]? and [Tf2N]? were found to be the most hydrophilic and hydrophobic anions, respectively. Conversely, the cation chain length did not influence the results. 相似文献
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Effect of the Cationic Surfactant Moiety on the Structure of Water Entrapped in Two Catanionic Reverse Micelles Created from Ionic Liquid‐Like Surfactants
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Cristian C. Villa Prof. Juana J. Silber Prof. N. Mariano Correa Dr. R. Darío Falcone 《Chemphyschem》2014,15(14):3097-3109
The behavior of water entrapped in reverse micelles (RMs) formed by two catanionic ionic liquid‐like surfactants, benzyl‐n‐hexadecyldimethylammonium 1,4‐bis‐2‐ethylhexylsulfosuccinate (AOT‐BHD) and cetyltrimethylammonium 1,4‐bis‐2‐ethylhexylsulfosuccinate (AOT‐CTA), was investigated by using dynamic (DLS) and static (SLS) light scattering, FTIR, and 1H NMR spectroscopy techniques. To the best of our knowledge, this is the first report in which AOT‐CTA has been used to create RMs and encapsulate water. DLS and SLS results revealed the formation of RMs in benzene and the interaction of water with the RM interface. From FTIR and 1H NMR spectroscopy data, a difference in the magnitude of the water–catanionic surfactant interaction at the interface is observed. For the AOT‐BHD RMs, a strong water–surfactant interaction can be invoked whereas for AOT‐CTA this interaction seems to be weaker. Consequently, more water molecules interact with the interface in AOT‐BHD RMs with a completely disrupted hydrogen‐bond network, than in AOT‐CTA RMs in which the water structure is partially preserved. We suggest that the benzyl group present in the BHD+ moiety in AOT‐BHD is responsible for the behavior of the catanionic interface in comparison with the interface created in AOT‐CTA. These results show that a simple change in the cationic component in the catanionic surfactant promotes remarkable changes in the RMs interface with interesting consequences, in particular when using the systems as nanoreactors. 相似文献
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Self‐Assembly of Imidazolium‐Based Surfactants in Magnetic Room‐Temperature Ionic Liquids: Binary Mixtures
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The phase behaviour of binary mixtures of ionic surfactants (1‐alkyl‐3‐imidazolium chloride, CnmimCl with n=14, 16 and 18) and imidazolium‐based ionic liquids (1‐alkyl‐3‐methylimidazolium tetrachloroferrate, CnmimFeCl4, with n=2 and 4) over a broad temperature range and the complete range of compositions is described. By using many complementary methods including differential scanning calorimetry (DSC), polarised microscopy, small‐angle neutron and X‐ray scattering (SANS/SAXS), and surface tension, the ability of this model system to support self‐assembly is described quantitatively and this behaviour is compared with common water systems. The existence of micelles swollen by the solvent can be deduced from SANS experiments and represent a possible model for aggregates, which has barely been considered for ionic‐liquid systems until now, and can be ascribed to the rather low solvophobicity of the surfactants. Our investigation shows that, in general, CnmimCl is a rather weak amphiphile in these ionic liquids. The amphiphilic strength increases systematically with the length of the alkyl chain, as seen from the phase behaviour, the critical micelle concentration, and also the level of definition of the aggregates formed. 相似文献
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Dr. Sarah E. Norman Adam H. Turner Dr. John D. Holbrey Dr. Tristan G. A. Youngs 《Chemphyschem》2016,17(23):3923-3931
The local solvation environment of uracil dissolved in the ionic liquid 1‐ethyl‐3‐methylimidazolium acetate has been studied using neutron diffraction techniques. At solvent:solute (ionic liquid:uracil) ratios of 3:1 and 2:1, little perturbation of the ion–ion correlations compared to those of the neat ionic liquid are observed. We find that solvation of the uracil is driven predominantly by the acetate anion of the solvent. While short distance correlations exist between uracil and the imidazolium cation, the geometry of these contacts suggest that they cannot be considered as hydrogen bonds, in contrast to other studies by Araújo et al. (J. M. Araújo, A. B. Pereiro, J. N. Canongia‐Lopes, L. P. Rebelo, I. M. Marrucho, J. Phys. Chem. B 2013, 117, 4109–4120 ). Nevertheless, this combination of interactions of the solute with both the cation and anion components of the solvents helps explain the high solubility of the nucleobase in this media. In addition, favourable uracil–uracil contacts are observed, of similar magnitude to those between cation and uracil, and are also likely to aid dissolution. 相似文献
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Yanfei Shen Dr. Yuanjian Zhang Dr. Daniel Kuehner Dr. Guifu Yang Dr. Fuyu Yuan Li Niu Prof. Dr. 《Chemphyschem》2008,9(15):2198-2202
We propose a simple but efficient, rapid, and quantitative ion‐responsive micelle system based on counter‐anion exchange of a surfactant with an imidazolium unit. The ion‐exchange reaction results in the amphiphilic‐to‐hydrophobic transition of the imidazolium salt, leading to the destruction of the micelles, which has been successfully applied to controlled release and emulsification. The proposed design offers a novel alternative stimulus to control these smart physical aggregates besides pH, temperature and light—with extra advantages. Our finding greatly benefits both fundamental research and industry. 相似文献
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采用等温滴定量热法、静态荧光猝灭法和电导法系统研究了典型离子液体1-烷基-3-甲基咪唑四氟硼酸盐([Cnmim][BF4])在水溶液中的聚集行为, 获得了胶束形成的临界胶束浓度(cmc), 摩尔焓变(ΔHmic), 摩尔吉布斯自由能变(ΔGmic), 摩尔熵变(ΔSmic)以及不同浓度时[Cnmim][BF4]胶束的平均聚集数等基本参数. 发现这类离子液体的聚集为熵驱动, 阳离子的烷基链越长, ΔGmic越负, 聚集更容易发生. 此外, 结合[Cnmim]X (X=Cl-, Br-)的相关研究发现, 阳离子相同时, 体积越大和疏水性越强的阴离子与头基的结合能力越强, 能有效地降低头基之间的静电排斥, 降低cmc, 利于胶束的形成. 对于[C12mim][BF4], 添加剂β-环糊精(β-CD)的加入可使cmc增大, ΔHmic和ΔSmic减小, 而KBF4则可使cmc和ΔHmic减小, ΔSmic增大. 相似文献
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A. Heintz J. K. Lehmann E. Schmidt A. Wandschneider 《Journal of solution chemistry》2009,38(8):1079-1083
Diffusion coefficients of the ionic liquids [C2MIM][EtSO4], [C4MIM][OcSO4], [C2MIM][NTf2] and [C4MIM][NTf2] in water at high dilution have been measured using the Taylor dispersion technique. Data on the diffusion coefficients have
been obtained for each solute at six temperatures between 288 and 313 K. The data have been fitted by the Arrhenius equation
and activation energies of diffusion have been determined. Effective radii of the ionic liquid molecules have also been obtained
using the Stokes–Einstein relationship. 相似文献
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尼罗红在离子表面活性剂水溶液中的荧光特性 总被引:1,自引:0,他引:1
尼罗红(NR)分子具有大的芳香环和基态时可与水分子形成氢键的吸电子基, 它对增溶在表面活性剂胶束栅栏层的环境尤其敏感, 在十二烷基三甲基溴化铵(C12TABr)胶束水溶液中表现为双重荧光, 最大发射波长分别位于578和630 nm. 十二烷基硫酸钠(SDS)胶束的反离子解离度大于C12TABr胶束, 这不仅增大了NR周边环境的极性, 也增多了溶剂化水, 导致与NR氢键作用增强, 荧光强度低于C12TABr, 但有效促进了分子内扭转电荷转移(TICT)激发态形成, 其布居甚至可达到98%以上, 表观上仅出现了在634 nm的单重荧光峰. NR对环境的敏感特性很好地反映了Gemini表面活性剂初始形成胶束的残缺结构信息, 是检测这类具有强烈相互作用两亲分子聚集行为的良好探针. 相似文献
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Enze Li Guoyong Wang Fangqin Cheng ShiLing Yuan 《Journal of Dispersion Science and Technology》2014,35(11):1520-1527
The aggregation behaviors of two trisiloxane-tailed surface active ionic liquids in water have been investigated by coarse-grained (CG) molecular dynamics simulation on the basis of MARTINI force field. The new CG model is developed from the optimized molecule computed by using density functional theory. Direct comparison of angles and bonds obtained from all-atom (AA) simulations with those calculated from the CG model has been conducted to validate the latter model. Excellent agreement between AA and CG demonstrates that the potential of the new CG model can represent the complex system well. The long time CG simulation has been performed to understand the formation process of micelles when dissolving ionic liquids in water. Vesicles were observed at the final stage of the simulation and their partially truncated views and density profiles were obtained to describe the structure in detail. 相似文献
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The temperature (T) and cationic chain length (n) evolution of the nanoscale structure of the sub-layering-threshold members of a model family of room temperature ionic liquids (RTILs) is investigated by x-ray scattering. The measured curves are computer-resolved into individual Teubner-Strey-like lineshapes. The polar-apolar layering is found to start at . Opposite n-trends are found at for the spacings and correlation lengths associated with the diffraction patterns’ two main peaks, and assigned to a shift of balance between the two main interactions, Coulomb and van der Waals, and to increasing packing constraints due to the addition of methylenes. The spacings’ thermal expansion coefficients are found to deviate from the macroscopically-measured values, and to anomalously decrease with increasing temperature. Finally, the reduced temperature scale, , ( melting temperature), is demonstrated to render the observed trends significantly more systematic than those on a conventional T scale. 相似文献
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Travis P. Holbrook Robson F. Storey 《Journal of polymer science. Part A, Polymer chemistry》2020,58(2):280-299
Ionic liquid-terminated polyisobutylene (PIB-IL) dispersants suitable for stabilization of carbonaceous deposits found in automotive lubricating oils were derived by the quaternization of tertiary amines (1-methyl-imidazole, pyridine, and isoquinoline) with primary bromide-terminated PIB. Characterization of PIB intermediate and PIB-IL dispersants was carried out by nuclear magnetic resonance, gel-permeation chromatography, thermogravimetric analysis (TGA), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and differential scanning calorimetry. PIB-IL micellization in dodecane and characteristics thereof (hydrodynamic radius, aggregation number, and critical micelle concentration) were investigated by static (SLS) and dynamic light scattering; whereupon, the self-association of PIB-IL was found to be highly sensitive to anion hydrophobicity. Qualitative adsorption of PIB-IL onto carbon black was confirmed by Fourier transform infrared and TGA measurements. Using Langmuir adsorption studies, the affinity for and adsorption to carbon black of PIB-IL were characterized. PIB-IL adsorption onto carbon black occurred via cation–π interactions and was identified to be highly dependent on the molar volume of the cation and independent of the anion. From the parameters obtained by the Langmuir adsorption isotherms, the spatial arrangement of PIB-IL on the carbon black surface was elucidated, in which all adsorbed PIB-IL were determined to exist in the elongated brush regime. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020 , 58, 280–299 相似文献
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Dipl.‐Chem. Sebastian Sahler Dipl.‐Biol. Sebastian Sturm Dipl.‐Chem. Michael T. Kessler Dr. Martin H. G. Prechtl 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(29):8934-8941
Ionic liquid (IL) based H2 storage for H2 generation from NH3BH3 derivatives is shown. These systems promote H2 generation at low temperature, with good reaction rates and high total H2 yields. The effects of ILs and the H2 yield in correlation with the basicity, the cations of the ILs, and the role of carbenes are discussed. Furthermore, mechanistic findings on the dehydrogenation are described. IL material blends are competitive with conventional H2 storage materials with experimental efficiencies of at least 6.5 wt % H2. 相似文献
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Monzer Fanun Sami Makharza Mukhles Sowwan 《Journal of Dispersion Science and Technology》2013,34(11):1561-1567
The systems investigated by fluorescence spectroscopy and atomic force microscopy were water/ethoxylated mono, di-glyceride/oil + ethanol. The oils were R (+)-limonene and isopropylmyristate. The mixing ratio (w/w) of ethanol/oil equals unity. The fluorescent probes auramine-O and 8-anilino-1-naphthalenesulfonic acid were used to determine the minimum ω′ value for the transition of reverse micelles to microemulsions in the systems based on the two oils, as well as at different surfactant contents. The fluorescence quenching of Safranine-T (3,6-diamino-2,7-dimethyl-5 phenyl phenazinium chloride) by the inorganic ions Fe2+, Fe3+ and Cu2+ was studied in reverse micelles and microemulsions. The Stern–Volmer quenching constants at different water/surfactant molar ratios (ω values) were calculated from the data of the quenching process. Atomic force microscopy was used to image the systems based on the two oils for different water to surfactant molar ratios below and above the minimum ω′ value. 相似文献
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离子液体作为潜在的“绿色”溶剂,具有许多传统溶剂无法比拟的优异性能,在有机合成、催化、液液分离和萃取等领域引起了广泛的研究。而在离子液体领域无机材料的制备是一个较新的发展分支,现已利用其合成出多种具有独特结构和性能的无机材料。本文就离子液体在无机材料制备方面的应用及发展趋势进行了综述。目前,对于制备无机材料,离子液体主要是作为电解液、表面活性剂或溶剂,本文介绍了其在应用中的优缺点,并指出该领域未来的发展趋势是离子热合成和集模板-溶剂-反应物于一身的离子液体反应。 相似文献