溴代1-己基-3-甲基咪唑离子液体与丙酮的相互作用

运用核磁共振氢谱和碳谱手段,研究了室温离了液体溴代1-己基-3-甲基咪唑([C6mim]Br)在不同浓度的离子液体/丙酮混合体系中的1H和13C化学位移．实验结果表明,离了液体[C6mim]Br的阴离子与丙酮甲基上的氢原子相互作用并形成了氢键．量子化学计算结果与核磁共振实验结果一致．     

Molecularly imprinted polymer based potentiometric sensor for the determination of 1-hexyl-3-methylimidazolium cation in aqueous solution

The molecular imprinting technique is powerful to prepare functional materials with molecular recognition properties. In this work, a potentiometric sensor was fabricated by dispersing molecularly imprinted polymers (MIPs) into plasticized PVC matrix and used for the determination of 1-hexyl-3-methylimidazolium cation ([C₆mim]⁺) in aqueous solution. The MIPs were synthesized by precipitation polymerization using 1-hexyl-3-methylimidazolium chloride ([C₆mim]Cl) as the template molecule, methacrylic acid (MAA) and ethylene glycol dimethacrylat (EGDMA) as the functional monomers, and EGDMA also as the cross-linking agent. The as-prepared electrode exhibited a Nernstian response (58.87 ± 0.3 mV per decade) to [C₆mim]⁺ in a concentration range from 1.0 × 10⁻⁶ to 0.1 mol kg⁻¹ with a low detection limit of 2.8 × 10⁻⁷ mol kg⁻¹, high selectivity, and little pH influence. The as-prepared electrode was used for the detection of the [C₆mim]⁺ in distilled water, tap water, and river water with a good recovery. It was also successfully applied in the determination of mean activity coefficients of [C₆mim]Br in fructose + water systems based on the potentiometric method at 298.15 K.

     

High pressure Raman study on the local structure of 1-ethyl-3-methylimidazolium tetrafluoroborate

We have investigated the pressure-induced Raman spectral changes of 1-ethyl-3-methylimidazolium tetrafluoroborate ([emim][BF₄]). We found that [emim][BF₄] did not crystallize up to 1.2 GPa. The Raman CH stretching spectra arising from the CH₃ groups of the ethyl-chain and the CH₃ group adjacent to the imidazolium-ring in [emim]⁺ cation largely changed against pressure. Moreover, the Raman intensity of the CH₂ (N) bending band arising from the alkyl-chain drastically changes with increasing pressure, but that of the imidazolium-ring in-plane bending band arising from the imidazolium-ring is independent of pressure. Our results show that the environment around the alkyl-chain of [emim][BF₄] is largely perturbed rather than that around the imidazolium-ring upon compression.     

1-butyl-3-methylimidazolium chloride assisted electrospinning of SAN/MWCNTs conductive reinforced composite membranes

The aim of this research was to investigate how the addition of IL [Bmim]Cl* and MWCNTs** into SAN*** solution will influence the viscosity and the electrical conductivity of the electrospinning solution and to find out the impact of IL and CNTs on the electrical and mechanical properties of the obtained membranes and on the morphology of the produced nanofibres. MWCNTs were added into two types of SAN solutions, with and without [Bmim]Cl, and then electrospinning was performed. All membranes were investigated by SEM analysis. The electrical conductivity and viscosity of the solutions were measured and their effect on the morphology of the fibres, as well as electrical and mechanical properties was estimated.     

The impact of 1-butyl-3-methylimidazolium chloride on electrospinning process of SAN polymer solutions and electrospun fiber morphology

The aim of this research was to investigate how addition of IL [Bmim]Cl¹ into SAN² solution in 1,2-DCE³ will influence electrospinning variables, stability of process and morphology of obtained nanofibers and find out the appropriate way of utilizing [Bmim]Cl in the electrospinning process. The solutions of pure SAN in 1,2-DCE of different concentrations (10–20%) and solutions with different concentrations (0.5–20%) of IL were spun at different variables (10–20 cm and 10–20 kV). All results were investigated by optical and SEM microscopy. Also solution parameters like electrical conductivity, surface tension and viscosity were measured and their effect on the obtained fibers morphology estimated.     

Influence of supersaturation on surface structure

Using low-energy electron microscopy, we have investigated the influence of an external flux on the structure of the Si(111) surface during growth and etching at elevated temperatures. We find that varying the adatom supersaturation effectively changes the surface free energies of coexisting 7 x 7 and '1 x 1' regions of the surface. In response, the boundaries separating the phases adopt a new steady-state configuration. The measured configuration can be used to quantitatively determine the difference in free energy between the phases, Deltagamma. The change in Deltagamma provides a measure of the local supersaturation at the surface, and can be interpreted as a change in the phase-transition temperature.     

Influence of surface on the nanocrystalline structure formation

In contrast to the common Fe-B-base amorphous alloys, Mössbauer transmission and CEMS studies of the early stages of the nanocrystalline structure formation in the new magnetically soft FeCuNbSiB alloys produced via the amorphous way, revealed that the primary crystallization of the Fe₃Si-like phase is inhibited by the surface. This result supports the role of copper as nucleation agent in the amorphous structure.     

Pressure-induced crystallization of 1-butyl-3-methylimidazolium hexafluorophosphate

We have investigated the pressure-induced crystallization of 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF₆]) associated with the conformational changes of [bmim]⁺ by Raman spectroscopy. [bmim]⁺ has trans-trans and gauche-trans (GT) conformers of the butyl side chain at ambient pressure. Our result revealed that liquid to solid-phase transition occurs at 0.2–0.4 GPa region, where the GT conformer becomes dominant. We found that the GT dominant state continues up to 4 GPa.     

1-羟乙基-3-甲基咪唑氯盐水溶液蒸汽压和凝固特性研究

1-羟乙基-3-甲基咪唑氯盐([HOEtMIM][Cl])是一种亲水性极强的离子液体,与水可以组成吸收式制冷工质对,具有良好的工业应用前景.在制冷工程应用中,离子液体水溶液的低温特性研究非常重要,包括低温段的水溶液蒸汽压数据和凝固特性,而[HOEtMIM][Cl]的相关研究缺乏.本文对水的质量分数分别为17.10%、24.29%、38.03%、49.89%、69.94%,温度范围(278.15K~408.15K)的[HOEtMIM][Cl]水溶液的汽液相平衡进行了测定;并对水的质量分数范围为1.3%~90.0%,温度范围为150K~360K的离子液体水溶液的凝固特性进行了测定,揭示其在低温应用时可能出现的固化问题.获得的蒸汽压及凝固特性数据对该离子液体水溶液应用于制冷系统设计具有重要意义.     

Influence of surface electronic structure on the Casimir force

Recent nonlocal microscopic theory of Casimir force which expresses the interaction energy between two metallic slabs in terms of surface polariton propagators calculated from diamagnetic and paramagnetic current-current response functions, sensitive to details of the surface electron density profiles and single-particle excitations on the surfaces, is used here to calculate various contributions to the Casimir energies for a silver film described by two different models. Current-current response functions are constructed from energy levels and wave functions obtained in two different models: jellium and Chulkov one-dimensional model potential, and the results are compared with the local plasmon model results. The results show how the details of such surface electronic structure modify Casimir force.     

Ionic conductivity and dielectric properties of potato starch-magnesium acetate biopolymer electrolytes: the effect of glycerol and 1-butyl-3-methylimidazolium chloride

In the present work, the effect of glycerol and 1-butyl-3-methylimidazolium chloride (BmImCl) on the conductivity and dielectric properties of potato starch doped with magnesium acetate, Mg(C₂H₃O₂)₂-based electrolytes is studied. The electrolytes are prepared via solution cast technique. The interaction between the materials is proven by Fourier transform infrared (FTIR) analysis. Electrolyte with 20 wt.% Mg(C₂H₃O₂)₂ exhibits a room temperature conductivity of (2.44 ± 0.37) × 10^?8 S cm^?1. The addition of 30 wt.% glycerol to the best polymer-salt composition has further enhanced the conductivity to (2.60 ± 0.42) × 10^?6 S cm^?1. A conductivity of (1.12 ± 0.08) × 10^?5 S cm^?1 has been achieved when 18 wt.% BmImCl is added to the best polymer-salt-plasticizer composition. From the loss tangent (tan δ) plot, the relaxation time (t _r) for selected electrolytes is determined. From transference number measurements, ions are found to be the dominant charge carriers.     

1-乙基-3-甲基咪唑四氟硼酸盐离子液体的量子化学研究

采用量子化学的从头算(abinitio)和密度泛函(DFT)方法,在6311++G计算水平上研究了离子液体1乙基3甲基咪唑四氟硼酸盐在气相模型下的离子对结构.经振动分析得到了离子对的红外谱,并利用自然键轨道(NBO)分析了阴阳离子与离子对的电荷布居差异.计算结果表明,离子对中存在氢键等弱相互作用.运用Counterpoise方法消除基组重叠误差,得到阴阳离子间的相互作用能为346.78kJ/mol.     

X-ray study of the structure of phospholipid monolayers on the water surface

The possibility of laboratory X-ray reflectometry study of the structure of dimyristoyl phosphatidylserine (DMPS) phospholipid monolayers on the water surface in various phase states has been demonstrated.     

On the structure of a water molecule chemisorbed on a metal surface

A model using the electrostatic image force and the harmonic restoring force has been adapted to find the equilibrium structure of a chemisorbed water molecule on a metal surface. An estimate of the maximum possible increase in the HOH interbond angle upon chemisorption due to image forces is given.     

Electrochemical behavior of cobalt from 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid

The electrodeposition of metallic cobalt from a 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid was investigated. The electrochemical behavior of Co(II) in the ionic liquid on a platinum working electrode at 60 °C was studied by cyclic voltammetry and chronoamperometry. The results from the cyclic voltammetry showed that the electrodeposition of metallic Co in the ionic liquid was an irreversible process and controlled by the diffusion of Co(II) on a platinum working electrode. The average value of αn_α was calculated to be 0.35 and the diffusion coefficient (D₀) of Co(II) was calculated to be 1.76 × 10⁻⁸ cm²/s at 60 °C. Chronoamperometric results indicated that the electrodeposition of Co on a platinum working electrode followed the mechanism of instantaneous nucleation and three-dimensional growth with diffusion-controlled. The cobalt plating was uniform, dense, shining in appearance with good adhesion to the platinum substrate at 60 °C. The scanning electron microscope (SEM) micrographs were used to confirm that the cobalt plating was denser and finer at 60 °C. Energy dispersive X-ray analysis (EDAX) profile showed that the obtained plating was pure cobalt. X-ray diffraction (XRD) pattern indicated that there was a preferred orientation direction and the average size of cobalt grains was 40 nm.     

Influence of surface oxidation on the structure and properties of cold metal cathodes

In the paper, methods of synthesizing oxide films on cold metal cathode surfaces, processes of electron emission from cold metal-metal oxide cathodes, sputtering of cold cathodes, and prospects for the development of emitting metal-metal oxide nanostructures with long operating lifetime are considered. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 27–34, February, 2007.     

Influence of MgO doping on the structure of monocrystalline LiNbO3

Conditions for the growth of LiNbO₃:MgO single crystals by the Czochralski method were optimized. An upper limit of the molar MgO concentration in the melt for obtaining limpid, optically homogeneous crystals was determined. The Curie temperature was measured on precisely defined samples and so real MgO contents in the single crystal phase, distribution coefficients and longitudinal concentration profiles could be determined using this calibration curve. X-ray diffraction and optical absorption in the near infra-red and in the ultra-violet and visible regions were also studied on LiNbO₃:MgO single crystals. Lattice constants and positions of the OH^– absorption band and of the short-wave absorption edge were determined on the basis of described measurements. Dependences of all the above-mentioned properties on the molar MgO concentration were found out. The simple model of microscopic mechanisms for explaining these experimental data was proposed.