The effect of various quantum mechanically derived partial atomic charges on the bulk properties of chloride-based ionic liquids

Energy Technology Data Exchange (ETDEWEB)

Zolghadr, Amin Reza, E-mail: arzolghadr@shirazu.ac.ir [Department of Chemistry, Shiraz University, Shiraz 71946-84795 (Iran, Islamic Republic of); Ghatee, Mohammad Hadi [Department of Chemistry, Shiraz University, Shiraz 71946-84795 (Iran, Islamic Republic of); Moosavi, Fatemeh [Department of Chemistry, Ferdowsi University of Mashhad, Mashhad 91779 (Iran, Islamic Republic of)

2016-08-22

Partial atomic charges using various quantum mechanical calculations for [C{sub n}mim]Cl (n = 1, 4) ionic liquids (ILs) are obtained and used for development of molecular dynamics simulation (MD) force fields. The isolated ion pairs are optimized using HF, B3LYP, and MP2 methods for electronic structure with 6-311++G(d,p) basis set. Partial atomic charges are assigned to the atomic center with CHELPG and NBO methods. The effect of these sets of partial charges on the static and dynamic properties of ILs is evaluated by performing a series of MD simulations and comparing the essential thermodynamic properties with the available experimental data and available molecular dynamics simulation results. In contrast to the general trends reported for ionic liquids with BF{sub 4}, PF{sub 6}, and iodide anions (in which restrained electrostatic potential (RESP) charges are preferred), partial charges derived by B3LYP-NBO method are relatively good in prediction of the structural, dynamical, and thermodynamic energetic properties of the chloride based ILs.

Fluorination effects on the thermodynamic, thermophysical and surface properties of ionic liquids

International Nuclear Information System (INIS)

Vieira, N.S.M.; Luís, A.; Reis, P.M.; Carvalho, P.J.; Lopes-da-Silva, J.A.; Esperança, J.M.S.S.; Araújo, J.M.M.; Rebelo, L.P.N.; Freire, M.G.; Pereiro, A.B.

2016-01-01

Highlights: • Surface tension of fluorinated ionic liquids. • Thermophysical properties of fluorinated ionic liquids. • Thermal properties and thermodynamic functions. - Abstract: This paper reports the thermal, thermodynamic, thermophysical and surface properties of eight ionic liquids with fluorinated alkyl side chain lengths equal or greater than four carbon atoms. Melting and decomposition temperatures were determined together with experimental densities, surface tensions, refractive indices, dynamic viscosities and ionic conductivities in a temperature interval ranging from (293.15 to 353.15) K. The surface properties of these fluorinated ionic liquids were discussed and several thermodynamic functions, as well as critical temperatures, were estimated. Coefficients of isobaric thermal expansion, molecular volumes and free volume effects were calculated from experimental values of density and refractive index and compared with previous data. Finally, Walden plots were used to evaluate the ionicity of the investigated ionic liquids.

Enhanced ionic diffusion in ionomer-filled nanopores

Energy Technology Data Exchange (ETDEWEB)

Allahyarov, Elshad, E-mail: elshad.allakhyarov@case.edu [Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine Universität Düsseldorf, Universitätstrasse 1, 40225 Düsseldorf (Germany); Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, Ohio 44106-7202 (United States); Theoretical Department, Joint Institute for High Temperatures, Russian Academy of Sciences (IVTAN), 13/19 Izhorskaya Street, Moscow 125412 (Russian Federation); International Research Centre, Baku State University, Baku (Azerbaijan); Taylor, Philip L. [Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106-7079 (United States); Löwen, Hartmut [Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine Universität Düsseldorf, Universitätstrasse 1, 40225 Düsseldorf (Germany)

2015-12-28

Coarse-grained simulations in the united-atom-model approximation are used to investigate confinement-induced morphological changes in Nafion-like ionomers. The system we study models a cylindrical pore in a hydrophobic matrix of supporting material with pore diameters that vary from 0.7 to 3.96 nm. Simulation results indicate a strong dependence of the equilibrium ionomer structures both on the pore diameter and on the sulfonate concentration in the pore. In the case of larger pores, the ionic clustering has the shape of a branched wire-like network oriented parallel to the pore axis. In the case of narrow pores, the ionic clusters occupy the pore center and exhibit strong density modulations both along the pore axis and across the pore diameter. The calculated diffusion coefficients for the ions indicate a sharp increase within the narrow pores. This finding is explained by ballistic-type ionic motion at shorter times and by the collective motion of ions in hydrophilic clusters. The influence of the hydrophobic walls on the distribution of ions and solvent molecules is discussed.

Enhanced ionic diffusion in ionomer-filled nanopores

International Nuclear Information System (INIS)

Allahyarov, Elshad; Taylor, Philip L.; Löwen, Hartmut

2015-01-01

Coarse-grained simulations in the united-atom-model approximation are used to investigate confinement-induced morphological changes in Nafion-like ionomers. The system we study models a cylindrical pore in a hydrophobic matrix of supporting material with pore diameters that vary from 0.7 to 3.96 nm. Simulation results indicate a strong dependence of the equilibrium ionomer structures both on the pore diameter and on the sulfonate concentration in the pore. In the case of larger pores, the ionic clustering has the shape of a branched wire-like network oriented parallel to the pore axis. In the case of narrow pores, the ionic clusters occupy the pore center and exhibit strong density modulations both along the pore axis and across the pore diameter. The calculated diffusion coefficients for the ions indicate a sharp increase within the narrow pores. This finding is explained by ballistic-type ionic motion at shorter times and by the collective motion of ions in hydrophilic clusters. The influence of the hydrophobic walls on the distribution of ions and solvent molecules is discussed

Visual indication of enviromental humidity by using poly(ionic liquid) photonic crystals.

Science.gov (United States)

Huang, Jing; Tao, Cheng-an; An, Qi; Lin, Changxu; Li, Xuesong; Xu, Dan; Wu, Yiguang; Li, Xiaogang; Shen, Dezhong; Li, Guangtao

2010-06-21

The combination of poly (ionic liquid) and photonic structure affords a new class of self-reporting humidity sensory materials with excellent reversibility, which are able to rapidly, sensitively and visually indicate environmental humidity with colour change from blue to green, orange, and red, covering the whole visible range.

Study of atomic and condensed atomic indices for reactive sites of ...

Indian Academy of Sciences (India)

Unknown

function indices in the framework of the AIM method of Bader.15 The atomic and group ... P Kolandaivel et al. 592. FF values. One of the reasons, they have argued, is that according to the analytic definition of FF it is valid only when ∆N → 0. In that case, the fluctuation in ..... In their work, they have concluded that the N atom ...

In Situ Atom Probe Deintercalation of Lithium-Manganese-Oxide.

Science.gov (United States)

Pfeiffer, Björn; Maier, Johannes; Arlt, Jonas; Nowak, Carsten

2017-04-01

Atom probe tomography is routinely used for the characterization of materials microstructures, usually assuming that the microstructure is unaltered by the analysis. When analyzing ionic conductors, however, gradients in the chemical potential and the electric field penetrating dielectric atom probe specimens can cause significant ionic mobility. Although ionic mobility is undesirable when aiming for materials characterization, it offers a strategy to manipulate materials directly in situ in the atom probe. Here, we present experimental results on the analysis of the ionic conductor lithium-manganese-oxide with different atom probe techniques. We demonstrate that, at a temperature of 30 K, characterization of the materials microstructure is possible without measurable Li mobility. Also, we show that at 298 K the material can be deintercalated, in situ in the atom probe, without changing the manganese-oxide host structure. Combining in situ atom probe deintercalation and subsequent conventional characterization, we demonstrate a new methodological approach to study ionic conductors even in early stages of deintercalation.

Ionic bonding of lanthanides, as influenced by d- and f-atomic orbitals, by core-shells and by relativity.

Science.gov (United States)

Ji, Wen-Xin; Xu, Wei; Schwarz, W H Eugen; Wang, Shu-Guang

2015-03-15

Lanthanide trihalide molecules LnX3 (X = F, Cl, Br, I) were quantum chemically investigated, in particular detail for Ln = Lu (lutetium). We applied density functional theory (DFT) at the nonrelativistic and scalar and SO-coupled relativistic levels, and also the ab initio coupled cluster approach. The chemically active electron shells of the lanthanide atoms comprise the 5d and 6s (and 6p) valence atomic orbitals (AO) and also the filled inner 4f semivalence and outer 5p semicore shells. Four different frozen-core approximations for Lu were compared: the (1s(2) -4d(10) ) [Pd] medium core, the [Pd+5s(2) 5p(6) = Xe] and [Pd+4f(14) ] large cores, and the [Pd+4f(14) +5s(2) 5p(6) ] very large core. The errors of LuX bonding are more serious on freezing the 5p(6) shell than the 4f(14) shell, more serious upon core-freezing than on the effective-core-potential approximation. The LnX distances correlate linearly with the AO radii of the ionic outer shells, Ln(3+) -5p(6) and X(-) -np(6) , characteristic for dominantly ionic Ln(3+) -X(-) binding. The heavier halogen atoms also bind covalently with the Ln-5d shell. Scalar relativistic effects contract and destabilize the LuX bonds, spin orbit coupling hardly affects the geometries but the bond energies, owing to SO effects in the free atoms. The relativistic changes of bond energy BE, bond length Re , bond force k, and bond stretching frequency vs do not follow the simple rules of Badger and Gordy (Re ∼BE∼k∼vs ). The so-called degeneracy-driven covalence, meaning strong mixing of accidentally near-degenerate, nearly nonoverlapping AOs without BE contribution is critically discussed. © 2015 Wiley Periodicals, Inc.

Ionic diffusion in quartz studied by transport measurements, SIMS and atomistic simulations

International Nuclear Information System (INIS)

Sartbaeva, Asel; Wells, Stephen A; Redfern, Simon A T; Hinton, Richard W; Reed, Stephen J B

2005-01-01

Ionic diffusion in the quartz-β-eucryptite system is studied by DC transport measurements, SIMS and atomistic simulations. Transport data show a large transient increase in ionic current at the α-β phase transition of quartz (the Hedvall effect). The SIMS data indicate two diffusion processes, one involving rapid Li + motion and the other involving penetration of Al and Li atoms into quartz at the phase transition. Atomistic simulations explain why the fine microstructure of twin domain walls in quartz near the transition does not hinder Li + diffusion

Ionic profile of honey as a potential indicator of botanical origin and global environmental pollution

International Nuclear Information System (INIS)

Fermo, Paola; Beretta, Giangiacomo; Maffei Facino, Roberto; Gelmini, Fabrizio; Piazzalunga, Andrea

2013-01-01

Aim of this study was to determine by Ion Chromatography ions (Na + , Ca ++ , Mg ++ , NH 4 + , Cl − , Br − , SO 4 2− , NO 3 − , PO 4 3− ) in honeys (honeydew and floral nectar honeys) from different Italian Regions and from countries of the Western Balkan area. The compositional data were processed by multivariate analysis (PCA and HCA). Arboreal honeydew honeys from the Western Balkans had higher concentrations (from two to three times) of some environmental pollutants (Br − , SO 4 2− and PO 4 3− contents), due to industrial and agricultural activities, than those from Italian regions. The cationic profiles were very similar in both groups. Multivariate analysis indicated a clear difference between nectar honeys and arboreal/honeydew honeys (recognition of the botanical origin). These findings point to the potential of ionic constituents of honey as indicators of environmental pollution, botanical origin and authenticity. -- Highlights: •Analysis by IC of honeys from two areas with different environmental pollution (Italy and Balkans). •Chemometric techniques such as PCA and HCA used. •In Balkans area higher Br − , SO 4 2− and PO 4 3− due to industrial and agricultural activities. •Discrimination of honey botanical origin and authenticity on the base of IC data. •Honey ionic profiles as indicators of environmental pollution and botanical origin. -- Capsule: Ionic profiles of honey could be potential indicators of environmental pollution (industrial and agricultural), botanical origin and authenticity

Ionic liquids: radiation chemistry, solvation dynamics and reactivity patterns

International Nuclear Information System (INIS)

Wishart, J.F.; Funston, A.M.; Szreder, T.

2006-01-01

slow solvation dynamics of the excess electron in ILs (which vary over a wide viscosity range) increases the importance of pre-solvated electron reactivity and consequently alters product distributions. Scavenging of the excess electron before it becomes fully solvated is a significant facet of the overall radiation sensitivity of ionic liquids, possibly due to less competition from slower electron solvation processes. Parallel measurements of excess electron solvation processes and emission dynamics (Stokes shift and polarization anisotropy decay) of solvatochromic coumarin-153 show that the reorganization dynamics of ionic liquids extend to much longer timescales (nanoseconds) than in conventional polar solvents (picoseconds). This phenomenon profoundly influences the reactivity and energetics of radiolytically-generated excess electrons. The slow solvation dynamics would also be expected to significantly alter transition state dynamics and provide a potential means to control product distribution. This becomes particularly important for transition states with a very different polarity from the reactants and/or products. Electron reactions with several aromatic acceptors, acids, and oxygen were measured in (MeBu 3 N + )(NTf 2 - ). Rate constants for solvated electron capture by benzophenone, pyrene and phenanthrene were on the order of 1.6x10 8 M -1 ·s -1 , typically 100 times slower than observed in conventional polar solvents. The reactions of hydrogen atoms with several of the same reactants were measured in the same ionic liquid. H-atoms react very rapidly with pyrene and phenanthrene (∼3 x 10 9 L·mol -1 ·s -1 ) to form H-adduct radicals. The H-atom rate constants are similar to the values measured or estimated for the same reactions in aqueous solutions. The H-atom reactions with the aromatic hydrocarbons must be diffusion-controlled, but are faster than diffusion-controlled reactions for solvated electrons in the same ionic liquid. The results indicate

Cold chemistry with ionic partners: quantum features of HeH+(1Σ) with H(1S) at ultralow energies.

Science.gov (United States)

Bovino, S; Tacconi, M; Gianturco, F A

2011-07-28

Quantum reactive calculations are presented for an ion-atom reaction involving the HeH(+)cation and its destruction via a barrierless interaction with H atoms. The range of collision energies considered is that of a cold trap regime (around and below millikelvin) where the ionic partner could be spatially confined. Specific resonant features caused by the interplay of the strong ionic interaction with the very slow partners' dynamics are found and analyzed. Indications are also given on the consequences of the abstraction mechanism that acts for this reaction at low energies. © 2011 American Chemical Society

Surface effects on ionic Coulomb blockade in nanometer-size pores.

Science.gov (United States)

Tanaka, Hiroya; Iizuka, Hideo; Pershin, Yuriy V; Ventra, Massimiliano Di

2018-01-12

Ionic Coulomb blockade in nanopores is a phenomenon that shares some similarities but also differences with its electronic counterpart. Here, we investigate this phenomenon extensively using all-atom molecular dynamics of ionic transport through nanopores of about one nanometer in diameter and up to several nanometers in length. Our goal is to better understand the role of atomic roughness and structure of the pore walls in the ionic Coulomb blockade. Our numerical results reveal the following general trends. First, the nanopore selectivity changes with its diameter, and the nanopore position in the membrane influences the current strength. Second, the ionic transport through the nanopore takes place in a hopping-like fashion over a set of discretized states caused by local electric fields due to membrane atoms. In some cases, this creates a slow-varying 'crystal-like' structure of ions inside the nanopore. Third, while at a given voltage, the resistance of the nanopore depends on its length, the slope of this dependence appears to be independent of the molarity of ions. An effective kinetic model that captures the ionic Coulomb blockade behavior observed in MD simulations is formulated.

Surface effects on ionic Coulomb blockade in nanometer-size pores

Science.gov (United States)

Tanaka, Hiroya; Iizuka, Hideo; Pershin, Yuriy V.; Di Ventra, Massimiliano

2018-01-01

Ionic Coulomb blockade in nanopores is a phenomenon that shares some similarities but also differences with its electronic counterpart. Here, we investigate this phenomenon extensively using all-atom molecular dynamics of ionic transport through nanopores of about one nanometer in diameter and up to several nanometers in length. Our goal is to better understand the role of atomic roughness and structure of the pore walls in the ionic Coulomb blockade. Our numerical results reveal the following general trends. First, the nanopore selectivity changes with its diameter, and the nanopore position in the membrane influences the current strength. Second, the ionic transport through the nanopore takes place in a hopping-like fashion over a set of discretized states caused by local electric fields due to membrane atoms. In some cases, this creates a slow-varying ‘crystal-like’ structure of ions inside the nanopore. Third, while at a given voltage, the resistance of the nanopore depends on its length, the slope of this dependence appears to be independent of the molarity of ions. An effective kinetic model that captures the ionic Coulomb blockade behavior observed in MD simulations is formulated.

Atom states and interatomic interactions in complex perovskite-like oxides. Communication XX. Origin of electron-ionic conductivity in lanthanum gallates doped with strontium and chromium

International Nuclear Information System (INIS)

Chezhina, N.V.; Zolotukhina, N.V.; Pijr, I.V.

2006-01-01

Magnetic susceptibilities and electric conductivities of solid solutions based on lanthanum gallate containing chromium and strontium atoms in the ratio of 10 : 2 were studied. It was shown that no partial oxidation of chromium to Cr(IV) occurs when lanthanum gallate is doped with chromium and strontium simultaneously, whereas the ionic conductivity is associated with the appearance of vacancies stabilized by chromium atoms in the oxygen sublattice [ru

3-Dimensional atomic scale structure of the ionic liquid-graphite interface elucidated by AM-AFM and quantum chemical simulations

Science.gov (United States)

Page, Alister J.; Elbourne, Aaron; Stefanovic, Ryan; Addicoat, Matthew A.; Warr, Gregory G.; Voïtchovsky, Kislon; Atkin, Rob

2014-06-01

In situ amplitude modulated atomic force microscopy (AM-AFM) and quantum chemical simulations are used to resolve the structure of the highly ordered pyrolytic graphite (HOPG)-bulk propylammonium nitrate (PAN) interface with resolution comparable with that achieved for frozen ionic liquid (IL) monolayers using STM. This is the first time that (a) molecular resolution images of bulk IL-solid interfaces have been achieved, (b) the lateral structure of the IL graphite interface has been imaged for any IL, (c) AM-AFM has elucidated molecular level structure immersed in a viscous liquid and (d) it has been demonstrated that the IL structure at solid surfaces is a consequence of both thermodynamic and kinetic effects. The lateral structure of the PAN-graphite interface is highly ordered and consists of remarkably well-defined domains of a rhomboidal superstructure composed of propylammonium cations preferentially aligned along two of the three directions in the underlying graphite lattice. The nanostructure is primarily determined by the cation. Van der Waals interactions between the propylammonium chains and the surface mean that the cation is enriched in the surface layer, and is much less mobile than the anion. The presence of a heterogeneous lateral structure at an ionic liquid-solid interface has wide ranging ramifications for ionic liquid applications, including lubrication, capacitive charge storage and electrodeposition.In situ amplitude modulated atomic force microscopy (AM-AFM) and quantum chemical simulations are used to resolve the structure of the highly ordered pyrolytic graphite (HOPG)-bulk propylammonium nitrate (PAN) interface with resolution comparable with that achieved for frozen ionic liquid (IL) monolayers using STM. This is the first time that (a) molecular resolution images of bulk IL-solid interfaces have been achieved, (b) the lateral structure of the IL graphite interface has been imaged for any IL, (c) AM-AFM has elucidated molecular level

Optical emission studies of atomic and ionic species in the ionized sputter-deposition process of magnesium oxide thin films

International Nuclear Information System (INIS)

Matsuda, Y.; Koyama, Y.; Iwaya, M.; Shinohara, M.; Fujiyama, H.

2005-01-01

Planar magnetron (PM) power and ICP-RF power dependences of the optical emission intensities of excited atomic and ionic species in the reactive ionized sputter-deposition of magnesium oxide (MgO) thin films were investigated. With the increase in PM power at constant ICP-RF power, Mg I emission intensity increased and Ar I emission intensity gradually decreased. With the increase in ICP-RF power at constant PM power, the Mg I emission intensity increased at lower ICP-RF power and then gradually decreased at higher ICP-RF power; on the contrary, Ar I emission intensity monotonically increased. Emission intensity of atomic oxygen was negligibly small compared with those of Mg I and Ar I under the metallic sputtering mode condition

Fluctuating hydrodynamics for ionic liquids

Energy Technology Data Exchange (ETDEWEB)

Lazaridis, Konstantinos [Department of Mathematics and Statistics, Washington State University, Pullman, 99163 (United States); Wickham, Logan [Department of Computer Science, Washington State University, Richland, 99354 (United States); Voulgarakis, Nikolaos, E-mail: n.voulgarakis@wsu.edu [Department of Mathematics and Statistics, Washington State University, Pullman, 99163 (United States)

2017-04-25

We present a mean-field fluctuating hydrodynamics (FHD) method for studying the structural and transport properties of ionic liquids in bulk and near electrified surfaces. The free energy of the system consists of two competing terms: (1) a Landau–Lifshitz functional that models the spontaneous separation of the ionic groups, and (2) the standard mean-field electrostatic interaction between the ions in the liquid. The numerical approach used to solve the resulting FHD-Poisson equations is very efficient and models thermal fluctuations with remarkable accuracy. Such density fluctuations are sufficiently strong to excite the experimentally observed spontaneous formation of liquid nano-domains. Statistical analysis of our simulations provides quantitative information about the properties of ionic liquids, such as the mixing quality, stability, and the size of the nano-domains. Our model, thus, can be adequately parameterized by directly comparing our prediction with experimental measurements and all-atom simulations. Conclusively, this work can serve as a practical mathematical tool for testing various theories and designing more efficient mixtures of ionic liquids. - Highlights: • A new fluctuating hydrodynamics method for ionic liquids. • Description of ionic liquid morphology in bulk and near electrified surfaces. • Direct comparison with experimental measurements.

Electric double-layer capacitance between an ionic liquid and few-layer graphene.

Science.gov (United States)

Uesugi, Eri; Goto, Hidenori; Eguchi, Ritsuko; Fujiwara, Akihiko; Kubozono, Yoshihiro

2013-01-01

Ionic-liquid gates have a high carrier density due to their atomically thin electric double layer (EDL) and extremely large geometrical capacitance Cg. However, a high carrier density in graphene has not been achieved even with ionic-liquid gates because the EDL capacitance CEDL between the ionic liquid and graphene involves the series connection of Cg and the quantum capacitance Cq, which is proportional to the density of states. We investigated the variables that determine CEDL at the molecular level by varying the number of graphene layers n and thereby optimising Cq. The CEDL value is governed by Cq at n 4. This transition with n indicates a composite nature for CEDL. Our finding clarifies a universal principle that determines capacitance on a microscopic scale, and provides nanotechnological perspectives on charge accumulation and energy storage using an ultimately thin capacitor.

Ionic structures and transport properties of hot dense W and U plasmas

Science.gov (United States)

Hou, Yong; Yuan, Jianmin

2016-10-01

We have combined the average-atom model with the hyper-netted chain approximation (AAHNC) to describe the electronic and ionic structure of uranium and tungsten in the hot dense matter regime. When the electronic structure is described within the average-atom model, the effects of others ions on the electronic structure are considered by the correlation functions. And the ionic structure is calculated though using the hyper-netted chain (HNC) approximation. The ion-ion pair potential is calculated using the modified Gordon-Kim model based on the electronic density distribution in the temperature-depended density functional theory. And electronic and ionic structures are determined self-consistently. On the basis of the ion-ion pair potential, we perform the classical (CMD) and Langevin (LMD) molecular dynamics to simulate the ionic transport properties, such as ionic self-diffusion and shear viscosity coefficients, through the ionic velocity correlation functions. Due that the free electrons become more and more with increasing the plasma temperature, the influence of the electron-ion collisions on the transport properties become more and more important.

High speed atom source

International Nuclear Information System (INIS)

Hoshino, Hitoshi.

1990-01-01

In a high speed atom source, since the speed is not identical between ions and electrons, no sufficient neutralizing effect for ionic rays due to the mixing of the ionic rays and the electron rays can be obtained failing to obtain high speed atomic rays at high density. In view of the above, a speed control means is disposed for equalizing the speed of ions forming ionic rays and the speed of electrons forming electron rays. Further, incident angle of the electron rays and/or ionic rays to a magnet or an electrode is made variable. As a result, the relative speed between the ions and the electrons to the processing direction is reduced to zero, in which the probability of association between the ions and the electrons due to the coulomb force is increased to improve the neutralizing efficiency to easily obtain fine and high density high speed electron rays. Further, by varying the incident angle, a track capable of obtaining an ideal mixing depending on the energy of the neutralized ionic rays is formed. Since the high speed electron rays has such high density, they can be irradiated easily to the minute region of the specimen. (N.H.)

Interactions in ion pairs of protic ionic liquids: Comparison with aprotic ionic liquids

International Nuclear Information System (INIS)

Tsuzuki, Seiji; Shinoda, Wataru; Miran, Md. Shah; Kinoshita, Hiroshi; Yasuda, Tomohiro; Watanabe, Masayoshi

2013-01-01

The stabilization energies for the formation (E form ) of 11 ion pairs of protic and aprotic ionic liquids were studied by MP2/6-311G ** level ab initio calculations to elucidate the difference between the interactions of ions in protic ionic liquids and those in aprotic ionic liquids. The interactions in the ion pairs of protic ionic liquids (diethylmethylammonium [dema] and dimethylpropylammonium [dmpa] based ionic liquids) are stronger than those of aprotic ionic liquids (ethyltrimethylammonium [etma] based ionic liquids). The E form for the [dema][CF 3 SO 3 ] and [dmpa][CF 3 SO 3 ] complexes (−95.6 and −96.4 kcal/mol, respectively) are significantly larger (more negative) than that for the [etma][CF 3 SO 3 ] complex (−81.0 kcal/mol). The same trend was observed for the calculations of ion pairs of the three cations with the Cl − , BF 4 − , TFSA − anions. The anion has contact with the N–H bond of the dema + or dmpa + cations in the most stable geometries of the dema + and dmpa + complexes. The optimized geometries, in which the anions locate on the counter side of the cations, are 11.0–18.0 kcal/mol less stable, which shows that the interactions in the ions pairs of protic ionic liquids have strong directionality. The E form for the less stable geometries for the dema + and dmpa + complexes are close to those for the most stable etma + complexes. The electrostatic interaction, which is the major source of the attraction in the ion pairs, is responsible for the directionality of the interactions and determining the magnitude of the interaction energy. Molecular dynamic simulations of the [dema][TFSA] and [dmpa][TFSA] ionic liquids show that the N–H bonds of the cations have contact with the negatively charged (oxygen and nitrogen) atoms of TFSA − anion, while the strong directionality of the interactions was not suggested from the simulation of the [etma][CF 3 SO 3 ] ionic liquid

Water-mediated ionic interactions in protein structures

Indian Academy of Sciences (India)

ISHWARYA( R SARANI( M KIRTI VAISHNAVI and K SEKAR. Supplementary table 1. List of complete water-mediated ionic interactions formed by different combinations of charged atoms and their corresponding occurrences. S. No. Type.

Case studies in atomic collision physics

CERN Document Server

McDaniel, Earl Wadsworth

1972-01-01

Case Studies in Atomic Collision Physics II focuses on studies on the role of atomic collision processes in astrophysical plasmas, including ionic recombination, electron transport, and position scattering. The book first discusses three-body recombination of positive and negative ions, as well as introduction to ionic recombination, calculation of the recombination coefficient, ions recombining in their parent gas, and three-body recombination at moderate and high gas-densities. The manuscript also takes a look at precision measurements of electron transport coefficients and differential cr

Degradation of 1-butyl-3-methylimidazolium chloride ionic liquid in a Fenton-like system

International Nuclear Information System (INIS)

Siedlecka, E.M.; Mrozik, W.; Kaczynski, Z.; Stepnowski, P.

2008-01-01

The study examined the usefulness of a Fenton-like system for the degradation of ionic liquid residues in water. The ionic liquid was oxidized in a dilute aqueous solution of 1-butyl-3-methylimidazolium chloride (bmimCl). The ionic liquid decomposes readily and rapidly in aqueous solution by chemical degradation in a Fenton-like system. Under chosen conditions the initial bmimCl solution was reduced by a factor of 0.973 within 90 min. Additional results showed that bmimCl degradations in a Fenton-like system in excess H 2 O 2 could be interpreted as a combined oxidation-reduction mechanism. Preliminary investigations of the mechanism of such degradations have indicated that initial OH· radicals can attack any one of the three carbon atoms on the imidazolium ring. The intermediates of this reaction may be mono- di- or amino- carboxylic acids

Predictive modeling studies for the ecotoxicity of ionic liquids towards the green algae Scenedesmus vacuolatus.

Science.gov (United States)

Das, Rudra Narayan; Roy, Kunal

2014-06-01

Hazardous potential of ionic liquids is becoming an issue of high concern with increasing application of these compounds in various industrial processes. Predictive toxicological modeling on ionic liquids provides a rational assessment strategy and aids in developing suitable guidance for designing novel analogues. The present study attempts to explore the chemical features of ionic liquids responsible for their ecotoxicity towards the green algae Scenedesmus vacuolatus by developing mathematical models using extended topochemical atom (ETA) indices along with other categories of chemical descriptors. The entire study has been conducted with reference to the OECD guidelines for QSAR model development using predictive classification and regression modeling strategies. The best models from both the analyses showed that ecotoxicity of ionic liquids can be decreased by reducing chain length of cationic substituents and increasing hydrogen bond donor feature in cations, and replacing bulky unsaturated anions with simple saturated moiety having less lipophilic heteroatoms. Copyright © 2013 Elsevier Ltd. All rights reserved.

Calculation of the valence charge density and binding energy in a simple metal according to the neutral atom method: the Hartree-Fock ionic potential

International Nuclear Information System (INIS)

Dagens, L.

1975-01-01

The neutral atom method is generalized in order to deal with a Hartree-Fock nonlocal ionic potential. It is used to test the following metal potential, based upon a theoretical analysis due to Hedin and Lundquist. The true HF potential is used to describe the ionic part and a simple local density scheme (the Gaspar-Kohn-Sham approximation) is used for the valence part. The method is first applied to the calculation of the rigid neutral atom valence density of a few simple metals and the corresponding form factor n(q). The choice of the ionic potential (HF or GKS) is found to have a small but significant effect as far as n(q) is concerned. A comparison with experiment is made for Al and Be, using the available X-rays structure factor measurements. Good agreement is obtained for Al with the recent results of Raccah and Heinrich. No agreement is obtained with the Be results of Brown, although the general behavior of the observed and theoretical n(g) as function of g (reciprocal vector length) are found to be quite similar. The binding energy is calculated for Li, Be, Na, Mg and Al, using the Nozieres-Pines formula for the valence-valence correlation energy. The agreement with observed values is improved considerably when the present (HF+GKS) scheme is used, instead of the HFS completely local density scheme used in a previous work. The remaining discrepancies may be ascribed to the inaccuracy of the NP formula and to the neglect of the whole valence-core correlation energy [fr

Importance of elastic finite-size effects: Neutral defects in ionic compounds

Science.gov (United States)

Burr, P. A.; Cooper, M. W. D.

2017-09-01

Small system sizes are a well-known source of error in density functional theory (DFT) calculations, yet computational constraints frequently dictate the use of small supercells, often as small as 96 atoms in oxides and compound semiconductors. In ionic compounds, electrostatic finite-size effects have been well characterized, but self-interaction of charge-neutral defects is often discounted or assumed to follow an asymptotic behavior and thus easily corrected with linear elastic theory. Here we show that elastic effects are also important in the description of defects in ionic compounds and can lead to qualitatively incorrect conclusions if inadequately small supercells are used; moreover, the spurious self-interaction does not follow the behavior predicted by linear elastic theory. Considering the exemplar cases of metal oxides with fluorite structure, we show that numerous previous studies, employing 96-atom supercells, misidentify the ground-state structure of (charge-neutral) Schottky defects. We show that the error is eliminated by employing larger cells (324, 768, and 1500 atoms), and careful analysis determines that elastic, not electrostatic, effects are responsible. The spurious self-interaction was also observed in nonoxide ionic compounds irrespective of the computational method used, thereby resolving long-standing discrepancies between DFT and force-field methods, previously attributed to the level of theory. The surprising magnitude of the elastic effects is a cautionary tale for defect calculations in ionic materials, particularly when employing computationally expensive methods (e.g., hybrid functionals) or when modeling large defect clusters. We propose two computationally practicable methods to test the magnitude of the elastic self-interaction in any ionic system. In commonly studied oxides, where electrostatic effects would be expected to be dominant, it is the elastic effects that dictate the need for larger supercells: greater than 96 atoms.

Water-soluble, triflate-based, pyrrolidinium ionic liquids

International Nuclear Information System (INIS)

Moreno, M.; Montanino, M.; Carewska, M.; Appetecchi, G.B.; Jeremias, S.; Passerini, S.

2013-01-01

Highlights: • Water-soluble, pyrrolidinium triflate ILs as solvents for extraction processes. • Electrolyte components for high safety, electrochemical devices. • Effect of the oxygen atom in the alkyl main side chain of pyrrolidinium cation. -- Abstract: The physicochemical and electrochemical properties of the water-soluble, N-methoxyethyl-N-methylpyrrolidinium trifluoromethanesulfonate (PYR 1(2O1) OSO 2 CF 3 ) ionic liquid (IL) were investigated and compared with those of commercial N-butyl-N-methylpyrrolidinium trifluoromethanesulfonate (PYR 14 OSO 2 CF 3 ). The results have shown that the transport properties are well correlated with the rheological and thermal behavior. The incorporation of an oxygen atom in the pyrrolidinium cation aliphatic side chain resulted in enhanced flexibility of the ether side chain, this supporting for the higher ionic conductivity, self-diffusion coefficient and density of PYR 1(2O1) OSO 2 CF 3 with respect to PYR 14 OSO 2 CF 3 , whereas no relevant effect on the crystallization of the ionic liquid was found. Finally, the presence of the ether side chain material in the pyrrolidinium cation led to a reduction in electrochemical stability, particularly on the cathodic verse

Probing Local Ionic Dynamics in Functional Oxides: From Nanometer to Atomic Scale

Science.gov (United States)

Kalinin, Sergei

2014-03-01

Vacancy-mediated electrochemical reactions in oxides underpin multiple applications ranging from electroresistive memories, to chemical sensors to energy conversion systems such as fuel cells. Understanding the functionality in these systems requires probing reversible (oxygen reduction/evolution reaction) and irreversible (cathode degradation and activation, formation of conductive filaments) electrochemical processes. In this talk, I summarize recent advances in probing and controlling these transformations locally on nanometer level using scanning probe microscopy. The localized tip concentrates the electric field in the nanometer scale volume of material, inducing local transition. Measured simultaneously electromechanical response (piezoresponse) or current (conductive AFM) provides the information on the bias-induced changes in material. Here, I illustrate how these methods can be extended to study local electrochemical transformations, including vacancy dynamics in oxides such as titanates, LaxSr1-xCoO3, BiFeO3, and YxZr1-xO2. The formation of electromechanical hysteresis loops and their bias-, temperature- and environment dependences provide insight into local electrochemical mechanisms. In materials such as lanthanum-strontium cobaltite, mapping both reversible vacancy motion and vacancy ordering and static deformation is possible, and can be corroborated by post mortem STEM/EELS studies. In ceria, a broad gamut of electrochemical behaviors is observed as a function of temperature and humidity. The possible strategies for elucidation ionic motion at the electroactive interfaces in oxides using high-resolution electron microscopy and combined ex-situ and in-situ STEM-SPM studies are discussed. In the second part of the talk, probing electrochemical phenomena on in-situ grown surfaces with atomic resolution is illustrated. I present an approach based on the multivariate statistical analysis of the coordination spheres of individual atoms to reveal

Ionic liquids: an x-ray reflectivity study

International Nuclear Information System (INIS)

Sloutskin, E.; Deutsch, M.; Tamam, L.; Ocko, B.; Kuzmenko, I.; Gog, T.

2005-01-01

Full Text:Ionic liquids are non-volatile, non-flammable and thermally stable solvents, and as such are promising 'green' replacements for traditional volatile organic solvents. In the last years hundreds of Ionic liquids were synthesized. Due to the Ionic liquids great industrial potential, this number is growing at an exceedingly fast rate. Despite the great importance of the interfacial properties of materials for technological applications and basic science, the atomic-scale surface structure of the Ionic liquids has never been studied previously. In our study, synchrotron x-ray reflectivity and surface tensiometry were employed to obtain the surface structure and thermodynamics of two ionic liquids, based on the 1-alkyl-3-methylimidazolium cations. A molecular layer of a density ∼18% higher than that of the bulk is found to form at the free surface of these liquids. The excess concentration of the oppositely charged ions within the surface layer is determined by chemical substitution of the anion. Finally, the observed layering at the surface is contrasted with our measurements on the behavior of classical aqueous salt solutions

Ionic liquids for separation of olefin-paraffin mixtures

Science.gov (United States)

Dai, Sheng; Luo, Huimin; Huang, Jing-Fang

2013-09-17

The invention is directed to an ionic liquid comprising (i) a cationic portion containing a complex of a silver (I) ion and one or more neutral ligands selected from organoamides, organoamines, olefins, and organonitriles, and (ii) an anionic portion having the chemical formula ##STR00001## wherein m and n are independently 0 or an integer of 1 or above, and p is 0 or 1, provided that when p is 0, the group --N--SO.sub.2--(CF.sub.2).sub.nCF.sub.3 subtended by p is replaced with an oxide atom connected to the shown sulfur atom. The invention is also directed to a method for separating an olefin from an olefin-paraffin mixture by passing the mixture through a layer of the ionic liquid described above.

Plasma-related matrix effects in inductively coupled plasma--atomic emission spectrometry by group I and group II matrix-elements

International Nuclear Information System (INIS)

Chan, George C.-Y.; Chan, W.-T.

2003-01-01

The effects of Na, K, Ca and Ba matrices on the plasma excitation conditions in inductively coupled plasma-atomic emission spectrometry (ICP-AES) were studied. Normalized relative intensity was used to indicate the extent of the plasma-related matrix effects. The group I matrices have no effects on the plasma excitation conditions. In contrast, the group II matrices depress the normalized relative intensities of some spectral lines. Specifically, the Group II matrices have no effects on the normalized relative intensity of atomic lines of low upper energy level (soft lines), but reduce the normalized relative intensity of some ionic lines and atomic lines of high energy level (hard lines). The Group II matrices seem to shift the Saha balance of the analytes only; no shift in the Boltzmann balance was observed experimentally. Moreover, for some ionic lines with sum of ionization and excitation potentials close to the ionization potential of argon (15.75 eV), the matrix effect is smaller than other ionic lines of the same element. The reduced matrix effects may be attributed qualitatively to charge transfer excitation mechanism of these ionic lines. Charge transfer reaction renders ionic emission lines from the quasi-resonant levels similar in characteristics of atomic lines. The contribution of charge transfer relative to excitation by other non-specific excitation mechanisms (via Saha balance and Boltzmann balance) determines the degree of atomic behavior of a quasi-resonant level. A significant conclusion of this study is that plasma-related matrix effect depends strongly on the excitation mechanism of a spectral line. Since, in general, more than one excitation mechanism may contribute to the overall excitation of an emission line, the observed matrix effects reflect the sum of the effects due to individual excitation mechanisms. Excitation mechanisms, in addition to the often-used total excitation energy, should be considered in matrix effect studies

Optical emission spectroscopy of metal-halide lamps: Radially resolved atomic state distribution functions of Dy and Hg

NARCIS (Netherlands)

Nimalasuriya, T.; Flikweert, A.J.; Stoffels, W.W.; Haverlag, M.; Mullen, van der J.J.A.M.; Pupat, N.B.M.

2006-01-01

Absolute line intensity measurements are performed on a metal-halide lamp. Several transitions of atomic and ionic Dy and atomic Hg are measured at different radial positions from which we obtain absolute atomic and ionic Dy intensity profiles. From these profiles we construct the radially resolved

Ionic liquids containing symmetric quaternary phosphonium cations and phosphorus-containing anions, and their use as lubricant additives

Science.gov (United States)

Qu, Jun; Luo, Huimin

2018-05-01

An ionic liquid composition having the following generic structural formula: ##STR00001## wherein R1, R2, R3, and R4 are equivalent and selected from hydrocarbon groups containing at least three carbon atoms, and X- is a phosphorus-containing anion, particularly an organophosphate, organophosphonate, or organophosphinate anion, or a thio-substituted analog thereof containing hydrocarbon groups with at least three carbon atoms. Also described are lubricant compositions comprising the above ionic liquid and a base oil, wherein the ionic liquid is dissolved in the base oil. Further described are methods for applying the ionic liquid or lubricant composition onto a mechanical device for which lubrication is beneficial, with resulting improvement in friction reduction, wear rate, and/or corrosion inhibition.

Molecular Simulation of Ionic Polyimides and Composites with Ionic Liquids as Gas-Separation Membranes.

Science.gov (United States)

Abedini, Asghar; Crabtree, Ellis; Bara, Jason E; Turner, C Heath

2017-10-24

Polyimides are at the forefront of advanced membrane materials for CO 2 capture and gas-purification processes. Recently, ionic polyimides (i-PIs) have been reported as a new class of condensation polymers that combine structural components of both ionic liquids (ILs) and polyimides through covalent linkages. In this study, we report CO 2 and CH 4 adsorption and structural analyses of an i-PI and an i-PI + IL composite containing [C 4 mim][Tf 2 N]. The combination of molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) simulations is used to compute the gas solubility and the adsorption performance with respect to the density, fractional free volume (FFV), and surface area of the materials. Our results highlight the polymer relaxation process and its correlation to the gas solubility. In particular, the surface area can provide meaningful guidance with respect to the gas solubility, and it tends to be a more sensitive indicator of the adsorption behavior versus only considering the system density and FFV. For instance, as the polymer continues to relax, the density, FFV, and pore-size distribution remain constant while the surface area can continue to increase, enabling more adsorption. Structural analyses are also conducted to identify the nature of the gas adsorption once the ionic liquid is added to the polymer. The presence of the IL significantly displaces the CO 2 molecules from the ligand nitrogen sites in the neat i-PI to the imidazolium rings in the i-PI + IL composite. However, the CH 4 molecules move from the imidazolium ring sites in the neat i-PI to the ligand nitrogen atoms in the i-PI + IL composite. These molecular details can provide critical information for the experimental design of highly selective i-PI materials as well as provide additional guidance for the interpretation of the simulated adsorption systems.

Modified ionic liquid cold-induced aggregation dispersive liquid-liquid microextraction followed by atomic absorption spectrometry for trace determination of zinc in water and food samples

International Nuclear Information System (INIS)

Zeeb, M.; Sadeghi, M.

2011-01-01

We report on a new method for the microextraction and determination of zinc (II). The ion is accumulated via ionic-liquid cold-induced aggregation dispersive liquid-liquid microextraction (IL-CIA-DLLME) followed by flame atomic absorption spectrometry (FAAS). The ionic liquid (IL) 1-hexyl-3-methylimidazolium hexafluorophosphate is dispersed into a heated sample solution containing sodium hexafluorophosphate as a common ion source. The solution is then placed in an ice-water bath upon which a cloudy solution forms due to the decrease of the solubility of the IL. Zinc is complexed with 8-hydroxyquinoline and extracted into the IL. The enriched phase is dissolved in a diluting agent and introduced to the FAAS. The method is not influenced by variations in the ionic strength of the sample solution. Factors affecting the performance were evaluated and optimized. At optimum conditions, the limit of detection is 0.18 μg L -1 , and the relative standard deviation is 3.0% (at n=5). The method was validated by recovery experiments and by analyzing a certified reference material and successfully applied to the determination of Zn (II) in water and food samples. (author)

Interaction of Rydberg atoms in circular states with the alkaline-earth Ca(4s{sup 2}) and Sr(5s{sup 2}) atoms

Energy Technology Data Exchange (ETDEWEB)

Mironchuk, E. S.; Narits, A. A.; Lebedev, V. S., E-mail: vlebedev@sci.lebedev.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

2015-11-15

The resonant mechanism of interaction of alkaline-earth atoms having a low electron affinity to Rydberg atoms in circular (l = vertical bar m vertical bar = n–1) and near-circular states has been studied. To describe the dynamics of resonant processes accompanied by nonadiabatic transitions between ionic and Rydberg covalent terms of a quasimolecule, an approach based on the integration of coupled equations for the probability amplitudes has been developed taking into account the possibility of the decay of an anion in the Coulomb field of the positive ionic core of a highly excited atom. The approach involves the specific features of the problem associated with the structure of the wavefunction of a Rydberg electron in states with high orbital angular momenta l ∼ n–1. This approach provides a much more accurate description of the dynamics of electronic transitions at collisions between atoms than that within the modified semiclassical Landau–Zener model. In addition, this approach makes it possible to effectively take into account many channels of the problem. The cross sections for resonant quenching of Rydberg states of the Li(nlm) atom with given principal n, orbital l = n–1, and magnetic m quantum numbers at thermal collisions with the Ca(4s{sup 2}) and Sr(5s{sup 2}) atoms have been calculated. The dependences of the results on n, m, and angle α between the relative velocity of the atoms and the normal to the plane of the orbit of the Rydberg electron have been obtained. The influence of orientational effects on the efficiency of the collisional destruction of circular and near-circular states has been studied. The results indicate a higher stability of such states to their perturbations by neutral particles as compared to usually studied nl states with low values of l (l ≪ n)

Lewis acidity dependency of the electrochemical window of zinc chloride-1-ethyl-3-methylimidazolium chloride ionic liquids

International Nuclear Information System (INIS)

Hsiu, S-I; Huang, J.-F.; Sun, I-W.; Yuan, C.-H.; Shiea, Jantaie

2002-01-01

Negative ion fast atom bombardment mass spectra (FAB-MS) recorded for ZnCl 2 -1-ethyl-3-methylimidazolium chloride (ZnCl 2 -EMIC) ionic liquids with various compositions indicate that various Lewis acidic chlorozincate clusters (ZnCl 3 - , Zn 2 Cl 5 - and Zn 3 Cl 7 - ) are present in ZnCl 2 -EMIC ionic liquids depending on the percentage of ZnCl 2 used in preparing the ionic liquids; higher ZnCl 2 percentage favors the larger clusters. Cyclic voltammetry reveals that the potential limits for a basic 1:3 ZnCl 2 -EMIC melt correspond to the cathodic reduction of EMI + and anodic oxidation of Cl - , giving an electrochemical window of approximately 3.0 V which is the same as that observed for basic AlCl 3 -EMIC ionic liquids. For acidic ionic liquids that have a ZnCl 2 /EMIC molar ratio higher than 0.5:1, the negative potential limit is due to the deposition of metallic zinc, and the positive potential limit is due to the oxidation of the chlorozincate complexes. All the acidic ionic liquids exhibit an electrochemical window of approximately 2 V, although the potential limits shifted in the positive direction with increasing ZnCl 2 mole ratio. Underpotential deposition of zinc was observed on Pt and Ni electrodes in the acidic ionic liquids. At proper temperatures and potentials, crystalline zinc electrodeposits were obtained from the acidic ionic liquids

Ultrasound-assisted ionic liquid dispersive liquid-liquid microextraction combined with graphite furnace atomic absorption spectrometric for selenium speciation in foods and beverages.

Science.gov (United States)

Tuzen, Mustafa; Pekiner, Ozlem Zeynep

2015-12-01

A rapid and environmentally friendly ultrasound assisted ionic liquid dispersive liquid liquid microextraction (USA-IL-DLLME) was developed for the speciation of inorganic selenium in beverages and total selenium in food samples by using graphite furnace atomic absorption spectrometry. Some analytical parameters including pH, amount of complexing agent, extraction time, volume of ionic liquid, sample volume, etc. were optimized. Matrix effects were also investigated. Enhancement factor (EF) and limit of detection (LOD) for Se(IV) were found to be 150 and 12 ng L(-1), respectively. The relative standard deviation (RSD) was found 4.2%. The accuracy of the method was confirmed with analysis of LGC 6010 Hard drinking water and NIST SRM 1573a Tomato leaves standard reference materials. Optimized method was applied to ice tea, soda and mineral water for the speciation of Se(IV) and Se(VI) and some food samples including beer, cow's milk, red wine, mixed fruit juice, date, apple, orange, grapefruit, egg and honey for the determination of total selenium. Copyright © 2015 Elsevier Ltd. All rights reserved.

Atomic processes relevant to polarization plasma spectroscopy

International Nuclear Information System (INIS)

Fujimoto, T.; Koike, F.; Sakimoto, K.; Okasaka, R.; Kawasaki, K.; Takiyama, K.; Oda, T.; Kato, T.

1992-04-01

When atoms (ions) are excited anisotropically, polarized excited atoms are produced and the radiation emitted by these atoms is polarized. From the standpoint of plasma spectroscopy research, we review the existing data for various atomic processes that are related to the polarization phenomena. These processes are: electron impact excitation, excitation by atomic and ionic collisions, photoexcitation, radiative recombination and bremsstrahlung. Collisional and radiative relaxation processes of atomic polarization follow. Other topics included are: electric-field measurement, self alignment, Lyman doublet intensity ratio, and magnetic-field measurement of the solar prominence. (author)

Structural and dynamic properties of solid state ionics

International Nuclear Information System (INIS)

Sakuma, T.

1995-01-01

The structural and dynamic properties of solid state ionics are reviewed. The low temperature phase transition of the copper halide-chalcogen compounds by specific heat measurements, electrical conductivity measurements and x-ray diffraction measurements are explained. The structures of solid state ionics investigated by the usual x-ray diffraction method and the anomalous x-ray scattering (AXS) measurement are discussed. The expression of the diffuse scattering intensity including the correlations among the thermal displacements of atoms has been given and applied to α-AgI type solid state ionics and lithium sulphate. The presence of low-energy excitations in crystalline copper ion conductors and the superionic conducting glass is investigated by neutron inelastic scattering measurements. The relation between the excitation energy and the mass of the cations is discussed. (author). 141 refs., 21 figs., 7 tabs

Ionic conductivity of N-alkyl pyridinium halides mesophases

International Nuclear Information System (INIS)

Meftah, Ahmed

1980-01-01

The quasi anhydrous N-alkyl pyridinium halides undergo at a temperature T c a phase transition from a crystalline isolating state to a conducting mesophase (σ = 3.10 -2 Ω -1 cm -1 ). The transition temperature depends on the nature on counter-ion and on the aliphatic chain length. The present study is devoted to the N-alkyl pyridinium chlorides, bromides and iodides varying the number of carbon atoms in the chain from ten to twenty two. The transition temperatures T c were found to increase from 30 deg. C up to 110 deg. C by a step of 10 deg. C for two added carbon atoms in the chain. The electrical measurements have shown that the conductivity of the mesophases which is ionic in origin is due to a large mobility of counter-ions in hydrophilic parts. At high frequencies (F > 10 3 Hz) ionic conductivity predominates in the bulk and does not depend on frequency. At low frequencies (F 3 Hz) the most important are interface phenomena depending on the square root of inverse frequency (ω -1/2 ) and being due to an electronic exchange limited by diffusion velocity of counter-ions. The electrical conductivity depends weekly on the chain length and the mesophases textures. The most conducting mesophase is the optically isotropic. The conductivity increases with increasing water content of the system and decreases with increasing atomic number of counter-ion. The diffusion measurements by radioactive tracers confirm the ionic character of charge carriers although the diffusion factors obtained by this method are largely higher than the calculated ones from the conductivity values. (author) [fr

Bond ionicity in crystals of transition metal compounds

International Nuclear Information System (INIS)

Kesler, Ya.A.

1989-01-01

A unified method of calculating bond ionicity in inorganic crystals is suggested. The approach presented envisages the sealing of d-electron contribution to ξ,p-electron contribution for the retention of community which can only be implemented by a self-consistent procedure. The results of self-consistent calculations of bond parameters of a number of crystals (ScN, Sc 2 O 3 , In 2 O 3 , J 2 O 3 ) as compared with the data for ξ,p-analogues are given. Ionicity changes in the series of analogous compounds utterly correspond to existing chemical concepts. The data for oxides of 4d-, 5d-elements (ZrO 2 , CeO 2 , ThO 2 ) and for a number of ternary compounds containing two types of bonds (LiNbO 3 , CdSc 2 S 4 , CdCr 2 Se 4 etc) are also given. In the case of transition elements ionicity to a great extent depends on the symmetry of anion environment and correlates to orbital population well. Ionicity values are in direct proportion to effective charges of atoms of transition elements

Electron excitation of alkali atoms

International Nuclear Information System (INIS)

Ormonde, S.

1979-02-01

The development and testing of a synthesized close-coupling effective model potential ten-channel electron-atom scattering code and some preliminary calculations of resonances in cross sections for the excitation of excited states of potassium by low energy electrons are described. The main results obtained are: identification of 1 S and 1 D structures in excitation cross sections below the 5 2 S threshold of neutral potassium; indications of additional structures - 1 P and 1 D between the 5 2 S and 5 2 D thresholds; and a suggested explanation of anomalously high interstate-electron impact excitation cross sections inferred from experiments on potassium-seeded plasmas. The effective potential model imbedded in the code can be used to simulate any atomic system that can be approximated by a single bound electron outside an ionic core. All that is needed is a set of effective potential parameters--experimental or theoretical. With minor modifications the code could be adapted to calculations of electron scattering by two-electron systems

Carbon films produced from ionic liquid carbon precursors

Science.gov (United States)

Dai, Sheng; Luo, Huimin; Lee, Je Seung

2013-11-05

The invention is directed to a method for producing a film of porous carbon, the method comprising carbonizing a film of an ionic liquid, wherein the ionic liquid has the general formula (X.sup.+a).sub.x(Y.sup.-b).sub.y, wherein the variables a and b are, independently, non-zero integers, and the subscript variables x and y are, independently, non-zero integers, such that ax=by, and at least one of X.sup.+ and Y.sup.- possesses at least one carbon-nitrogen unsaturated bond. The invention is also directed to a composition comprising a porous carbon film possessing a nitrogen content of at least 10 atom %.

Studies in hot atom and radiation chemistry. Progress report, December 1, 1979-November 30, 1980

International Nuclear Information System (INIS)

Koski, W.S.

1980-09-01

/sub nThe results on the reactive scattering of B + ( 3 P/sub u/) by D 2 has been published and a corresponding study on the ground state ( 1 S/sub g/) of B + has been submitted for publication. The ionic aspect of the Br-ethane hot atom system is being investigated using beam techniques. It is found that there is no direct reaction of Br + with ethane which can explain the thermal ionic yield of CH 3 Br reported by hot atom chemists for the Br-ethane hot atom system. Likewise, no satisfactory explanation exists for the dependence of the thermal ionic yield of CH 3 Br on moderator mole fraction. Studies of the collisions of Br + with Kr (which is used as a moderator in hot atom systems) shows that ions such as BrKr + are formed. Electron irradiation of CH 3 Br-Kr mixtures shows that CH 3 BrKr + is formed in good yield. Electron irradiation of Br 2 -Kr mixtures shows that ions such as Br(Kr)/sub n/ + are formed. Such ions can be produced in the Kr moderated Br-ethane hot atom system and can explain the thermal ionic yield of CH 3 Br and its dependence on Kr pressure

Physico-Chemical and Structural Interpretation of Discrete Derivative Indices on N-Tuples Atoms

Science.gov (United States)

Martínez-Santiago, Oscar; Marrero-Ponce, Yovani; Barigye, Stephen J.; Le Thi Thu, Huong; Torres, F. Javier; Zambrano, Cesar H.; Muñiz Olite, Jorge L.; Cruz-Monteagudo, Maykel; Vivas-Reyes, Ricardo; Vázquez Infante, Liliana; Artiles Martínez, Luis M.

2016-01-01

This report examines the interpretation of the Graph Derivative Indices (GDIs) from three different perspectives (i.e., in structural, steric and electronic terms). It is found that the individual vertex frequencies may be expressed in terms of the geometrical and electronic reactivity of the atoms and bonds, respectively. On the other hand, it is demonstrated that the GDIs are sensitive to progressive structural modifications in terms of: size, ramifications, electronic richness, conjugation effects and molecular symmetry. Moreover, it is observed that the GDIs quantify the interaction capacity among molecules and codify information on the activation entropy. A structure property relationship study reveals that there exists a direct correspondence between the individual frequencies of atoms and Hückel’s Free Valence, as well as between the atomic GDIs and the chemical shift in NMR, which collectively validates the theory that these indices codify steric and electronic information of the atoms in a molecule. Taking in consideration the regularity and coherence found in experiments performed with the GDIs, it is possible to say that GDIs possess plausible interpretation in structural and physicochemical terms. PMID:27240357

Thermodynamics of non-ionic surfactant Triton X-100-cationic surfactants mixtures at the cloud point

International Nuclear Information System (INIS)

Batigoec, Cigdem; Akbas, Halide; Boz, Mesut

2011-01-01

Highlights: → Non-ionic surfactants are used as emulsifier and solubilizate in such as textile, detergent and cosmetic. → Non-ionic surfactants occur phase separation at temperature as named the cloud point in solution. → Dimeric surfactants have attracted increasing attention due to their superior surface activity. → The positive values of ΔG cp 0 indicate that the process proceeds nonspontaneous. - Abstract: This study investigates the effects of gemini and conventional cationic surfactants on the cloud point (CP) of the non-ionic surfactant Triton X-100 (TX-100) in aqueous solutions. Instead of visual observation, a spectrophotometer was used for measurement of the cloud point temperatures. The thermodynamic parameters of these mixtures were calculated at different cationic surfactant concentrations. The gemini surfactants of the alkanediyl-α-ω-bis (alkyldimethylammonium) dibromide type, on the one hand, with different alkyl groups containing m carbon atoms and an ethanediyl spacer, referred to as 'm-2-m' (m = 10, 12, and 16) and, on the other hand, with -C 16 alkyl groups and different spacers containing s carbon atoms, referred to as '16-s-16' (s = 6 and 10) were synthesized, purified and characterized. Additions of the cationic surfactants to the TX-100 solution increased the cloud point temperature of the TX-100 solution. It was accepted that the solubility of non-ionic surfactant containing polyoxyethylene (POE) hydrophilic chain was a maximum at the cloud point so that the thermodynamic parameters were calculated at this temperature. The results showed that the standard Gibbs free energy (ΔG cp 0 ), the enthalpy (ΔH cp 0 ) and the entropy (ΔS cp 0 ) of the clouding phenomenon were found positive in all cases. The standard free energy (ΔG cp 0 ) increased with increasing hydrophobic alkyl chain for both gemini and conventional cationic surfactants; however, it decreased with increasing surfactant concentration.

Studies of Ionic Photoionization Using Relativistic Random Phase Approximation and Relativistic Multichannel Quantum Defect Theory

Science.gov (United States)

Haque, Ghousia Nasreen

The absorption of electromagnetic radiation by positive ions is one of the fundamental processes of nature which occurs in every intensely hot environment. Due to the difficulties in producing sufficient densities of ions in a laboratory, there are very few measurements of ionic photoabsorption parameters. On the theoretical side, some calculations have been made of a few major photoionization parameters, but generally speaking, most of the work done so far has employed rather simple single particle models and any theoretical work which has adequately taken into account intricate atomic many-body and relativistic effects is only scanty. In the present work, several complex aspects of atomic/ionic photoabsorption parameters have been studied. Non -resonant photoionization in neon and argon isonuclear as well as isoelectronic sequences has been studied using a very sophisticated technique, namely the relativistic random phase approximation (RRPA). This technique takes into account relativistic effects as well as an important class of major many-body effects on the same footing. The present calculations confirmed that gross features of photoionization parameters calculated using simpler models were not an artifact of the simple model. Also, the present RRPA calculations on K^+ ion and neutral Ar brought out the relative importance of various many-body effects such the inter-channel coupling. Inter-channel coupling between discrete bound state photoexcitation channels from an inner atomic/ionic level and photoionization continuum channels from an outer atomic/ionic level leads to the phenomena of autoionization resonances in the photoionization process. These resonances lead to very complex effects in the atomic/ionic photoabsorption spectra. These resonances have been calculated and studied in the present work in the neon and magnesium isoelectronic sequences using the relativistic multi-channel quantum defect theory (RMQDT) within the framework of the RRPA. The

Physico-Chemical and Structural Interpretation of Discrete Derivative Indices on N-Tuples Atoms

Directory of Open Access Journals (Sweden)

Oscar Martínez-Santiago

2016-05-01

Full Text Available This report examines the interpretation of the Graph Derivative Indices (GDIs from three different perspectives (i.e., in structural, steric and electronic terms. It is found that the individual vertex frequencies may be expressed in terms of the geometrical and electronic reactivity of the atoms and bonds, respectively. On the other hand, it is demonstrated that the GDIs are sensitive to progressive structural modifications in terms of: size, ramifications, electronic richness, conjugation effects and molecular symmetry. Moreover, it is observed that the GDIs quantify the interaction capacity among molecules and codify information on the activation entropy. A structure property relationship study reveals that there exists a direct correspondence between the individual frequencies of atoms and Hückel’s Free Valence, as well as between the atomic GDIs and the chemical shift in NMR, which collectively validates the theory that these indices codify steric and electronic information of the atoms in a molecule. Taking in consideration the regularity and coherence found in experiments performed with the GDIs, it is possible to say that GDIs possess plausible interpretation in structural and physicochemical terms.

Effect of ionic and non-ionic contrast media on whole blood viscosity, plasma viscosity and hematocrit in vitro

International Nuclear Information System (INIS)

Aspelin, P.

1978-01-01

The effect of the ionic contrast media diatrizoate, iocarmate and metrizoate and the non-ionic metrizamide on whole blood viscosity, plasma viscosity and hematocrit was investigated. All the contrast media increased whole blood and plasma viscosity and reduced the hematocrit. The whole blood viscosity increased with increasing osmolality of the contrast medium solutions, whereas the plasma viscosity increased with increasing viscosity of the contrast medium solutions. The higher the osmolality of the contrast media, the lower the hematocrit became. The normal shear-thinning (decreasing viscosity with increasing shear rate) property of blood was reduced when contrast medium was added to the blood. At 50 per cent volume ratio (contrast medium to blood), the ionic contrast media converted the blood into a shear-thickening (increasing viscosity with increasing shear rate) suspension, indicating a marked rigidification of the single red cell, while the non-ionic contrast medium still produced shear-thinning, indicating less rigidification of the red cell (p<0.01). (Auth.)

Atomic switches: atomic-movement-controlled nanodevices for new types of computing

International Nuclear Information System (INIS)

Hino, Takami; Hasegawa, Tsuyoshi; Terabe, Kazuya; Tsuruoka, Tohru; Nayak, Alpana; Ohno, Takeo; Aono, Masakazu

2011-01-01

Atomic switches are nanoionic devices that control the diffusion of metal cations and their reduction/oxidation processes in the switching operation to form/annihilate a metal atomic bridge, which is a conductive path between two electrodes in the on-state. In contrast to conventional semiconductor devices, atomic switches can provide a highly conductive channel even if their size is of nanometer order. In addition to their small size and low on-resistance, their nonvolatility has enabled the development of new types of programmable devices, which may achieve all the required functions on a single chip. Three-terminal atomic switches have also been developed, in which the formation and annihilation of a metal atomic bridge between a source electrode and a drain electrode are controlled by a third (gate) electrode. Three-terminal atomic switches are expected to enhance the development of new types of logic circuits, such as nonvolatile logic. The recent development of atomic switches that use a metal oxide as the ionic conductive material has enabled the integration of atomic switches with complementary metal-oxide-semiconductor (CMOS) devices, which will facilitate the commercialization of atomic switches. The novel characteristics of atomic switches, such as their learning and photosensing abilities, are also introduced in the latter part of this review. (topical review)

Interaction of radionickel with diatomite as a function of pH, ionic strength and temperature

International Nuclear Information System (INIS)

Xue Wang

2013-01-01

Sequestration of Ni(II) on diatomite as a function of reaction time, pH, ionic strength, foreign ions and temperature were investigated by batch sorption technique. The results indicated that the sorption of Ni(II) on diatomite was quickly in the first contact time of 2 h and then slowly with increasing contact time. The interaction of Ni(II) with diatomite was strongly pH- and ionic strength-dependent at low pH values (i.e., which was dominated by ion exchange or outer-sphere surface complexation), while the pH-dependent and ionic strength-independent sorption at high pH suggested that inner-sphere or multinuclear surface complexation was the main sorption mechanism. With increasing temperature, the sorption of Ni(II) on diatomite increased and the experimental data were well fitted by Langmuir model. The sorption samples at pH 6.8 and 10.0 were also characterized by XPS spectroscopy, and the results suggested that Si atoms also participated in Ni(II) sorption on diatomite. The results are important to evaluate the physicochemical behavior of Ni(II) and other similar radionuclides and heavy metal ions in the environment. (author)

Isotopic enrichment of 15N by ionic exchange chromatography

International Nuclear Information System (INIS)

Trivelin, P.C.O.

1979-01-01

The present paper presents some studies on production of 15 N-enriched ammonium sulphate with 5% atoms by ionic exchange chromatography method. Two systems are described of columns of resin, where experiments were conducted by eluition of NH 4 + bands with sodium hydroxide solution. Analyses were made of the cost of production of 15 N-enriched ammonium sulphate 5% atoms and, based on the experiments developed, a cost was obtained which was compatible with the international price of the product. The isotopic analyses of nitrogen were made by mass spectrometry. (Author) [pt

In situ emulsification microextraction using a dicationic ionic liquid followed by magnetic assisted physisorption for determination of lead prior to micro-sampling flame atomic absorption spectrometry

International Nuclear Information System (INIS)

Shokri, Masood; Beiraghi, Asadollah; Seidi, Shahram

2015-01-01

For the first time, a simple and efficient in situ emulsification microextraction method using a dicationic ionic liquid followed by magnetic assisted physisorption was presented to determine trace amounts of lead. In this method, 400 μL of 1.0 mol L −1 lithium bis (trifluoromethylsulfonyl) imide aqueous solution, Li[NTf 2 ], was added into the sample solution containing 100 μL of 1.0 mol L −1 1,3-(propyl-1,3-diyl) bis (3-methylimidazolium) chloride, [pbmim]Cl 2 , to form a water immiscible ionic liquid, [pbmim][NTf 2 ] 2 . This new in situ formed dicationic ionic liquid was applied as the acceptor phase to extract the lead-ammonium pyrrolidinedithiocarbamate (Pb-APDC) complexes from the sample solution. Subsequently, 30 mg of Fe 3 O 4 magnetic nanoparticles (MNPs) were added into the sample solution to collect the fine droplets of [pbmim][NTf 2 ] 2 , physisorptively. Finally, MNPs were eluted by acetonitrile, separated by an external magnetic field and the obtained eluent was subjected to micro-sampling flame atomic absorption spectrometry (FAAS) for further analysis. Comparing with other microextraction methods, no special devices and centrifugation step are required. Parameters influencing the extraction efficiency such as extraction time, pH, concentration of chelating agent, amount of MNPs and coexisting interferences were studied. Under the optimized conditions, this method showed high extraction recovery of 93% with low LOD of 0.7 μg L −1 . Good linearity was obtained in the range of 2.5–150 μg L −1 with determination coefficient (r 2 ) of 0.9921. Relative standard deviation (RSD%) for seven repeated measurements at the concentration of 10 μg L −1 was 4.1%. Finally, this method was successfully applied for determination of lead in some water and plant samples. - Highlights: • A dicationic ionic liquid was used as the extraction solvent, for the first time. • A simple and efficient in situ emulsification microextraction

A model for self-diffusion of guanidinium-based ionic liquids: a molecular simulation study.

Science.gov (United States)

Klähn, Marco; Seduraman, Abirami; Wu, Ping

2008-11-06

We propose a novel self-diffusion model for ionic liquids on an atomic level of detail. The model is derived from molecular dynamics simulations of guanidinium-based ionic liquids (GILs) as a model case. The simulations are based on an empirical molecular mechanical force field, which has been developed in our preceding work, and it relies on the charge distribution in the actual liquid. The simulated GILs consist of acyclic and cyclic cations that were paired with nitrate and perchlorate anions. Self-diffusion coefficients are calculated at different temperatures from which diffusive activation energies between 32-40 kJ/mol are derived. Vaporization enthalpies between 174-212 kJ/mol are calculated, and their strong connection with diffusive activation energies is demonstrated. An observed formation of cavities in GILs of up to 6.5% of the total volume does not facilitate self-diffusion. Instead, the diffusion of ions is found to be determined primarily by interactions with their immediate environment via electrostatic attraction between cation hydrogen and anion oxygen atoms. The calculated average time between single diffusive transitions varies between 58-107 ps and determines the speed of diffusion, in contrast to diffusive displacement distances, which were found to be similar in all simulated GILs. All simulations indicate that ions diffuse by using a brachiation type of movement: a diffusive transition is initiated by cleaving close contacts to a coordinated counterion, after which the ion diffuses only about 2 A until new close contacts are formed with another counterion in its vicinity. The proposed diffusion model links all calculated energetic and dynamic properties of GILs consistently and explains their molecular origin. The validity of the model is confirmed by providing an explanation for the variation of measured ratios of self-diffusion coefficients of cations and paired anions over a wide range of values, encompassing various ionic liquid classes

Electron density analysis of 1-butyl-3-methylimidazolium chloride ionic liquid.

Science.gov (United States)

del Olmo, Lourdes; Morera-Boado, Cercis; López, Rafael; García de la Vega, José M

2014-06-01

An analysis of the electron density of different conformers of the 1-butyl-3-methylimidazolium chloride (bmimCl) ionic liquid by using DFT through the BVP86 density functional has been obtained within the framework of Bader's atom in molecules (AIM), localized orbital locator (LOL), natural bond orbital (NBO), and deformed atoms in molecules (DAM). We also present an analysis of the reduced density gradients that deliver the non-covalent interaction regions and allow to understand the nature of intermolecular interactions. The most polar conformer can be characterized as ionic by AIM, LOL, and DAM methods while the most stable and the least polar shows shared-type interactions. The NBO method allows to comprehend what causes the stabilization of the most stable conformer based on analysis of the second-order perturbative energy and the charge transferred among the natural orbitals involved in the interaction.

Semiconductor nanocrystals dispersed in imidazolium-based ionic liquids: a spectroscopic and morphological investigation

International Nuclear Information System (INIS)

Panniello, Annamaria; Binetti, Enrico; Ingrosso, Chiara; Curri, M. Lucia; Agostiano, Angela; Tommasi, Raffaele; Striccoli, Marinella

2013-01-01

A growing interest is devoted to the study of imidazolium-based ionic liquids as innovative materials to combine with functional elements for advanced technological applications. Materials based on semiconductor and oxide nanocrystals in ionic liquids can be promising for their integration in lithium batteries, as well as in innovative solar cells. Although the physical chemical properties and the solvation dynamics of bare ionic liquids have been extensively studied, their combination with colloidal nanocrystals still remains almost unexplored. Here, the optical properties of organic-capped luminescent cadmium selenide nanocrystals coated by a shell of zinc sulfide (CdSe(ZnS)) dispersed in 1,3-dialkyl imidazolium ionic liquids have been investigated, also in dependence of the alkyl chain length on the imidazolium ring and of the anion nature, by using both time-integrated and time-resolved optical spectroscopy. The observed variations in decay profiles of the ionic liquid in presence of colloidal nanocrystals suggest that the dispersion of the nanostructures induces modifications in the ionic liquid structural order. Finally, atomic force microscopy analysis has provided insight into the topography of the investigated dispersions deposited as film, confirming the organization of the ionic liquids in super-structures, also upon nanocrystal incorporation.

Ionic Adsorption and Desorption of CNT Nanoropes

Directory of Open Access Journals (Sweden)

Jun-Jun Shang

2016-09-01

Full Text Available A nanorope is comprised of several carbon nanotubes (CNTs with different chiralities. A molecular dynamic model is built to investigate the ionic adsorption and desorption of the CNT nanoropes. The charge distribution on the nanorope is obtained by using a modified gradient method based on classical electrostatic theory. The electrostatic interactions among charged carbon atoms are calculated by using the Coulomb law. It was found here that the charged nanorope can adsorb heavy metal ions, and the adsorption and desorption can be realized by controlling the strength of applied electric field. The distance between the ions and the nanorope as well as the amount of ions have an effect on the adsorption capacity of the nanorope. The desorption process takes less time than that of adsorption. The study indicates that the CNT nanorope can be used as a core element of devices for sewage treatment.

Electroreduction Property and MD Simulation of Nitrobenzene in Ionic Liquid [BMim][Tf2N]/[BMim][BF4

International Nuclear Information System (INIS)

Zeng, Jianping; Zhang, Yinxu; Sun, Ruyao; Chen, Song

2014-01-01

energies between nitrobenzene and different ionic liquids with and without water is little difference. The variation trend of diffusion coefficients in different composite ionic liquids is consistent with that of interaction energies. Analyzing pair correlation functions showed that the bonding and nonbonding interactions are formed between the N, S and O atoms of ionic liquid and the N and O atoms of nitrobenzene. The diffusion is mainly caused by the nonbonding interaction between nitrobenzene and composite ionic liquid, and the interactions with water molecules are obviously greater than that without water. The conclusion is consistent with the experimental results

First-principles simulations on the new hybrid phases of germanene with alkali metal atoms coverage

Energy Technology Data Exchange (ETDEWEB)

Yuan, Jianmei [Hunan Key Laboratory for Computation and Simulation in Science and Engineering, School of Mathematics and Computational Science, Xiangtan University, Hunan 411105 (China); Tang, Chan; Zhong, Jianxin [Hunan Key Laboratory for Micro-Nano Energy Materials and Devices, School of Physics and Optoelectronic Engineering, Xiangtan University, Hunan 411105 (China); Mao, Yuliang, E-mail: ylmao@xtu.edu.cn [Hunan Key Laboratory for Micro-Nano Energy Materials and Devices, School of Physics and Optoelectronic Engineering, Xiangtan University, Hunan 411105 (China)

2016-01-01

Graphical abstract: - Highlights: • The predicted new phase of complete lithiated germanene is more favorable to form than germanane. • Besides ionic interactions, covalent component in some extent leads the complete lithiated germanene into a semiconductor. • 2D phases of Ge{sub 2}X{sub 1} (X = Li, Na, K) are metallic with weak polarization. • Half-lithiated germanene exhibits local magnetic moments on the Ge atoms neighbored with Li adatoms. - Abstract: We present first-principles calculations of a new type hybrid phases composed by buckled germanene with saturated or half-saturated alkali metal atoms adsorption. Our energetics and electronic structure analysis suggests that adsorbed alkali metal atoms (Li, Na, K) can be used as covered adatoms to synthesize germanene-based new phases in two dimensional. The predicted new phases of Ge{sub 2}X{sub 2} and Ge{sub 2}X{sub 1} (X = Li, Na, K) relative to the single germanene sheet could exist at room temperature. The formation energy of Ge{sub 2}Li{sub 2} configuration obtained from complete lithiation is even more favorable than that of germanane. Charge transfer is significant between the alkali metal atoms and Ge, indicating the ionic interactions between them. Furthermore, our charge density analysis indicates that covalent component in some extent exists in Ge{sub 2}X{sub 2} and Ge{sub 2}X{sub 1} (X = Li, Na, K) 2D phases, which even leads the complete lithiated germanene into a semiconductor with an energy gap of 0.14 eV. We report that 2D phases of Ge{sub 2}X{sub 1} (X = Li, Na, K) are metallic with weak polarization on the Fermi level and in unoccupied states. It is found that half-lithiated germanene exhibits local magnetic moments of 0.48 μ{sub B} on the Ge atoms neighbored with Li adatoms.

Effect of Ionic Strength on Settling of Activated Sludge

OpenAIRE

M Ahmadi Moghadam, M Soheili, MM Esfahani

2005-01-01

Structural properties of activated sludge flocs were found to be sensitive to small changes in ionic strength. This study investigates the effect of ionic strength on settling of activated sludge. Samples were taken from activated sludge process of Ghazvin Sasan soft drink wastewater treatment plant, then treated with different ionic strengths of KCl and CaCl2 solution, after that the turbidity of supernatant was measured. The results indicated that low ionic strength resulted in a steeper sl...

Combination of the ionic-to-atomic line intensity ratios from two test elements for the diagnostic of plasma temperature and electron number density in Inductively Coupled Plasma Atomic Emission Spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Tognoni, E. [Istituto per i Processi Chimico-Fisici, Area della Ricerca del Consiglio Nazionale delle Ricerche Via Moruzzi 1, 56124 Pisa (Italy)], E-mail: tognoni@ipcf.cnr.it; Hidalgo, M.; Canals, A. [Departamento de Quimica Analitica, Nutricion y Bromatologia. Universidad de Alicante. Apdo. 99, 03080, Alicante (Spain); Cristoforetti, G.; Legnaioli, S.; Salvetti, A.; Palleschi, V. [Istituto per i Processi Chimico-Fisici, Area della Ricerca del Consiglio Nazionale delle Ricerche Via Moruzzi 1, 56124 Pisa (Italy)

2007-05-15

In Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) spectrochemical analysis, the MgII(280.270 nm)/MgI(285.213 nm) ionic to atomic line intensity ratio is commonly used as a monitor of the robustness of operating conditions. This approach is based on the univocal relationship existing between intensity ratio and plasma temperature, for a pure argon atmospheric ICP in thermodynamic equilibrium. In a multi-elemental plasma in the lower temperature range, the measurement of the intensity ratio may not be sufficient to characterize temperature and electron density. In such a range, the correct relationship between intensity ratio and plasma temperature can be calculated only when the complete plasma composition is known. We propose the combination of the line intensity ratios of two test elements (double ratio) as an effective diagnostic tool for a multi-elemental low temperature LTE plasma of unknown composition. In particular, the variation of the double ratio allows us discriminating changes in the plasma temperature from changes in the electron density. Thus, the effects on plasma excitation and ionization possibly caused by introduction of different samples and matrices in non-robust conditions can be more accurately interpreted. The method is illustrated by the measurement of plasma temperature and electron density in a specific analytic case.

Two-photon emission and multiphoton absorption by atoms

International Nuclear Information System (INIS)

Mu, X.

1988-01-01

This thesis consists of investigations of two problems concerning photon-atom interactions. The first topic deals with two-photon transitions in atomic inner shells. An independent-particle model has been used to describe the two-photon transitions between different inner-shell electron states. The first relativistic self-consistent-field calculation of these transition rates in Ag, Mo, and Xe has been carried out. The theoretical results are compared with recent measurements. Good agreement with measured rates is found except in some cases where more reliable experiments still need to be done. The second topic is multiphoton multiionization of atoms. The maximum entropy principle has been employed in this theoretical investigation. A detailed statistical analysis of measured ionic charge distributions produced in strong laser pulses has been carried out. The results of this analysis indicates that the charge-state distribution is a Poissonian, rather than the binomial which prevails under infrared radiation, and hence that ionization occurs stepwise during the pulse. This result is shown to be consistent with experimental data

Theoretical development of atomic structure: Past, present and future

International Nuclear Information System (INIS)

Tiwary, S.N.

1994-11-01

Theoretical development of atomic structure is briefly discussed. The role of correlation, relativity, quantum electrodynamic (QED), finite nuclear size (FNS) and parity nonconservation (PNC) in high precision theoretical investigation of properties of atomic and ionic systems is demonstrated. At present, we do not have a comprehensive and practical atomic structure theory which accounts all these physical effects on an equal footing. Suggestions are made for future directions. (author). 108 refs, 5 figs, 9 tabs

Continuum electrostatics for ionic solutions with non-uniform ionic sizes

International Nuclear Information System (INIS)

Li Bo

2009-01-01

This work concerns electrostatic properties of an ionic solution with multiple ionic species of possibly different ionic sizes. Such properties are described by the minimization of an electrostatic free-energy functional of ionic concentrations. Bounds are obtained for ionic concentrations with low electrostatic free energies. Such bounds are used to show that there exists a unique set of equilibrium ionic concentrations that minimizes the free-energy functional. The equilibrium ionic concentrations are found to depend sorely on the equilibrium electrostatic potential, resembling the classical Boltzmann distributions that relate the equilibrium ionic concentrations to the equilibrium electrostatic potential. Unless all the ionic and solvent molecular sizes are assumed to be the same, explicit formulae of such dependence are, however, not available in general. It is nevertheless proved that in equilibrium the ionic charge density is a decreasing function of the electrostatic potential. This determines a variational principle with a convex functional for the electrostatic potential

Intrinsic electronic defects and multiple-atom processes in the oxidic semiconductor Ga2O3

Science.gov (United States)

Schmeißer, Dieter; Henkel, Karsten

2018-04-01

We report on the electronic structure of gallium oxide (Ga2O3) single crystals as studied by resonant photoelectron spectroscopy (resPES). We identify intrinsic electronic defects that are formed by mixed-atomic valence states. We differentiate three coexisting defect states that differ in their electronic correlation energy and their spatial localization lengths. Their relative abundance is described by a fractional ionicity with covalent and ionic bonding contributions. For Ga2O3, our analyses of the resPES data enable us to derive two main aspects: first, experimental access is given to determine the ionicity based on the original concepts of Pauling and Phillips. Second, we report on multi-atomic energy loss processes in the Ga2p core level and X-ray absorption data. The two experimental findings can be explained consistently in the same context of mixed-atomic valence states and intrinsic electronic defects.

AtomPy: an open atomic-data curation environment

Science.gov (United States)

Bautista, Manuel; Mendoza, Claudio; Boswell, Josiah S; Ajoku, Chukwuemeka

2014-06-01

We present a cloud-computing environment for atomic data curation, networking among atomic data providers and users, teaching-and-learning, and interfacing with spectral modeling software. The system is based on Google-Drive Sheets, Pandas (Python Data Analysis Library) DataFrames, and IPython Notebooks for open community-driven curation of atomic data for scientific and technological applications. The atomic model for each ionic species is contained in a multi-sheet Google-Drive workbook, where the atomic parameters from all known public sources are progressively stored. Metadata (provenance, community discussion, etc.) accompanying every entry in the database are stored through Notebooks. Education tools on the physics of atomic processes as well as their relevance to plasma and spectral modeling are based on IPython Notebooks that integrate written material, images, videos, and active computer-tool workflows. Data processing workflows and collaborative software developments are encouraged and managed through the GitHub social network. Relevant issues this platform intends to address are: (i) data quality by allowing open access to both data producers and users in order to attain completeness, accuracy, consistency, provenance and currentness; (ii) comparisons of different datasets to facilitate accuracy assessment; (iii) downloading to local data structures (i.e. Pandas DataFrames) for further manipulation and analysis by prospective users; and (iv) data preservation by avoiding the discard of outdated sets.

Ionic character of polar crystals: An extended Mulliken scheme for electronegativities

International Nuclear Information System (INIS)

Watson, R.E.; Bennett, L.H.; Davenport, J.W.

1983-01-01

The total energy of an atom can be expressed in terms of the charge q on the atom as E(q) = E(0)+αq+βq 2 +γq 3 . It is shown that the expected charge transfer q, which brings the intra-atomic energy of the atoms to a minimum, between otherwise isolated noninteracting atoms, is proportional to the difference in the α's of the constituent elements, i.e., q = c Δα. Thus α provides a well-defined electronegativity scale, and if the third-order term γq 3 may be neglected, then α = Phi/sub m/, which is the original Mulliken scale. The quadratic term βq 2 acts to oppose charge transfer, and therefore the coefficient c, relating q to Δα, depends on what elements are involved and on their relative concentration in a well-defined manner. This implies an asymmetry in charge transfer with concentration. Spectroscopic data indicate that γ, though small, is not negligible and, in such a case Phi/sub m/ is not a proper electronegativity. The extended Mulliken scheme, involving α and β, is relevant to the energetics of charge transfer and hence to the ionic character of insulating and semiconducting compounds. It allows simple baseline estimates to be made of such character. Other factors contribute to charge transfer and some of the complications associated with transition-metal compound formation are explored

Atomic-scale friction on stepped surfaces of ionic crystals.

Science.gov (United States)

Steiner, Pascal; Gnecco, Enrico; Krok, Franciszek; Budzioch, Janusz; Walczak, Lukasz; Konior, Jerzy; Szymonski, Marek; Meyer, Ernst

2011-05-06

We report on high-resolution friction force microscopy on a stepped NaCl(001) surface in ultrahigh vacuum. The measurements were performed on single cleavage step edges. When blunt tips are used, friction is found to increase while scanning both up and down a step edge. With atomically sharp tips, friction still increases upwards, but it decreases and even changes sign downwards. Our observations extend previous results obtained without resolving atomic features and are associated with the competition between the Schwöbel barrier and the asymmetric potential well accompanying the step edges.

Short wavelength sources and atoms and ions

International Nuclear Information System (INIS)

Kennedy, E.T.

2008-01-01

The interaction of ionizing radiation with atoms and ions is a key fundamental process. Experimental progress has depended in particular on the development of short wavelength light sources. Laser-plasma and synchrotron sources have been exploited for several decades and most recently the development of short wavelength Free Electron Laser (FEL) sources is revolutionizing the field. This paper introduces laser plasma and synchrotron sources through examples of their use in studies of the interaction of ionizing radiation with atoms and ions, ranging from few-electron atomic and ionic systems to the many-electron high atomic number actinides. The new FEL source (FLASH) at DESY is introduced. (author)

AtomPy: An Open Atomic Data Curation Environment for Astrophysical Applications

Directory of Open Access Journals (Sweden)

Claudio Mendoza

2014-05-01

Full Text Available We present a cloud-computing environment, referred to as AtomPy, based on Google-Drive Sheets and Pandas (Python Data Analysis Library DataFrames to promote community-driven curation of atomic data for astrophysical applications, a stage beyond database development. The atomic model for each ionic species is contained in a multi-sheet workbook, tabulating representative sets of energy levels, A-values and electron impact effective collision strengths from different sources. The relevant issues that AtomPy intends to address are: (i data quality by allowing open access to both data producers and users; (ii comparisons of different datasets to facilitate accuracy assessments; (iii downloading to local data structures (i.e., Pandas DataFrames for further manipulation and analysis by prospective users; and (iv data preservation by avoiding the discard of outdated sets. Data processing workflows are implemented by means of IPython Notebooks, and collaborative software developments are encouraged and managed within the GitHub social network. The facilities of AtomPy are illustrated with the critical assessment of the transition probabilities for ions in the hydrogen and helium isoelectronic sequences with atomic number Z ≤ 10.

Crystal structure of dimethylformamidium bis(trifluoromethanesulfonylamide: an ionic liquid

Directory of Open Access Journals (Sweden)

Allan Jay P. Cardenas

2016-09-01

Full Text Available At 100 K, the title molecular salt, C3H8NO+·C2F6NO4S2−, has orthorhombic (P212121 symmetry; the amino H atom of bis(trifluoromethanesulfonylamine (HNTf2 was transferred to the basic O atom of dimethylformamide (DMF when the ionic liquid components were mixed. The structure displays an O—H...N hydrogen bond, which links the cation to the anion, which is reinforced by a non-conventional C—H...O interaction, generating an R22(7 loop. A further very weak C—H...O interaction generates an [001] chain.

Ionic thermometers

International Nuclear Information System (INIS)

Strnad, M.

1975-01-01

An original method of temperature measurement based on conductivity changes near the phase transition point of ionic compounds and suitable for the range from 200 to 700 0 C according to the thermometric compound used, is given. By choosing between two approaches it is posible to evaluate either a discrete value of temperature or continuous measurement in a range to about 50 0 C below the phase transition point of thermometric compounds. The extreme nonlinearity of conductivity of the chosen group of ionic crystals used as well as the technical applications developed in the laboratories have not previously been published. The aim of the research is the application of this measuring method for temperature indication in nuclear reactors. Preliminary tests in radiation fields in an experimental reactor are yielding a real hope in this direction. (author)

New Pyrazolium Salts as a Support for Ionic Liquid Crystals and Ionic Conductors.

Science.gov (United States)

Pastor, María Jesús; Sánchez, Ignacio; Campo, José A; Schmidt, Rainer; Cano, Mercedes

2018-04-03

Ionic liquid crystals (ILCs) are a class of materials that combine the properties of liquid crystals (LCs) and ionic liquids (ILs). This type of materials is directed towards properties such as conductivity in ordered systems at different temperatures. In this work, we synthesize five new families of ILCs containing symmetrical and unsymmetrical substituted pyrazolium cations, with different alkyl long-chains, and anions such as Cl - , BF₄ - , ReO₄ - , p -CH₃-₆H₄SO₃ - (PTS) and CF₃SO₃ - (OTf). We study their thermal behavior by polarized light optical microscopy (POM) and differential scanning calorimetry (DSC). All of them, except those with OTf as counteranion, show thermotropic mesomorphism. The observations by POM reveal textures of lamellar mesophases. Those agree with the arrangement observed in the X-ray crystal structure of [H₂pz R(4),R(4) ][ReO₄]. The nature of the mesophases is also confirmed by variable temperature powder X-ray diffraction. On the other hand, the study of the dielectric properties at variable temperature in mesomorphic (Cl - and BF₄ - ) and non-mesomorphic (OTf) salts indicates that the supramolecular arrangement of the mesophase favors a greater ionic mobility and therefore ionic conductivity.

Primary processes and ionic reactions in the chemistry of recoiling silicon atoms

International Nuclear Information System (INIS)

Gaspar, P.P.; Garmestani, K.; Boo, B.H.; Stewart, G.W.

1993-01-01

Hot atom chemistry has permitted the elucidation of the chemistry of free atoms, and these include the polyvalent atoms of refractory group 14 elements, that is, carbon, silicon and germanium. Since no more than two bonds are formed normally in a single reactive collision of free atoms, the study on the chemistry of atoms like C, Si and Ge that require the formation of more than two bonds to saturate their chemical valence necessarily involves the study of reactive intermediates. By the studies on the chemistry of recoiling 31 Si atoms, the mechanistic conclusions reached are reported. The most important unanswered questions concerning the reaction of recoiling 31 Si atoms in the systems are shown, and progress has been made toward the answering. By using tetramethyl silane as a trapping agent for silicon ions, it has been established that the reaction of 31 Si ions contributes significantly to the formation of products in recoil systems. The studies by various researchers on this theme are reported. (K.I.)

Thermodynamics of interaction of ionic liquids with lipid monolayer.

Science.gov (United States)

Bhattacharya, G; Mitra, S; Mandal, P; Dutta, S; Giri, R P; Ghosh, S K

2018-06-01

Understanding the interaction of ionic liquids with cellular membrane becomes utterly important to comprehend the activities of these liquids in living organisms. Lipid monolayer formed at the air-water interface is employed as a model system to follow this interaction by investigating important thermodynamic parameters. The penetration kinetics of the imidazolium-based ionic liquid 1-decyl-3-methylimidazolium tetrafluoroborate ([DMIM][BF4]) into the zwitterionic 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid layer is found to follow the Boltzmann-like equation that reveals the characteristic time constant which is observed to be the function of initial surface pressure. The enthalpy and entropy calculated from temperature-dependent pressure-area isotherms of the monolayer show that the added ionic liquids bring about a disordering effect in the lipid film. The change in Gibbs free energy indicates that an ionic liquid with longer chain has a far greater disordering effect compared to an ionic liquid with shorter chain. The differential scanning calorimetric measurement on a multilamellar vesicle system shows the main phase transition temperature to shift to a lower value, which, again, indicates the disordering effect of the ionic liquid on lipid membrane. All these studies fundamentally point out that, when ionic liquids interact with lipid molecules, the self-assembled structure of a cellular membrane gets perturbed, which may be the mechanism of these molecules having adverse effects on living organisms.

Atomic and molecular theory

International Nuclear Information System (INIS)

Inokuti, Mitio.

1990-01-01

The multifaceted role of theoretical physics in understanding the earliest stages of radiation action is discussed. Scientific topics chosen for the present discourse include photoabsorption, electron collisions, and ionic collisions, and electron transport theory, Connections of atomic and molecular physics with condensed-matter physics are also discussed. The present article includes some historical perspective and an outlook for the future. 114 refs., 3 figs

Atomic and molecular theory

Energy Technology Data Exchange (ETDEWEB)

Inokuti, Mitio.

1990-01-01

The multifaceted role of theoretical physics in understanding the earliest stages of radiation action is discussed. Scientific topics chosen for the present discourse include photoabsorption, electron collisions, and ionic collisions, and electron transport theory, Connections of atomic and molecular physics with condensed-matter physics are also discussed. The present article includes some historical perspective and an outlook for the future. 114 refs., 3 figs.

Simulating chemical reactions in ionic liquids using QM/MM methodology.

Science.gov (United States)

Acevedo, Orlando

2014-12-18

The use of ionic liquids as a reaction medium for chemical reactions has dramatically increased in recent years due in large part to the numerous reported advances in catalysis and organic synthesis. In some extreme cases, ionic liquids have been shown to induce mechanistic changes relative to conventional solvents. Despite the large interest in the solvents, a clear understanding of the molecular factors behind their chemical impact is largely unknown. This feature article reviews our efforts developing and applying mixed quantum and molecular mechanical (QM/MM) methodology to elucidate the microscopic details of how these solvents operate to enhance rates and alter mechanisms for industrially and academically important reactions, e.g., Diels-Alder, Kemp eliminations, nucleophilic aromatic substitutions, and β-eliminations. Explicit solvent representation provided the medium dependence of the activation barriers and atomic-level characterization of the solute-solvent interactions responsible for the experimentally observed "ionic liquid effects". Technical advances are also discussed, including a linear-scaling pairwise electrostatic interaction alternative to Ewald sums, an efficient polynomial fitting method for modeling proton transfers, and the development of a custom ionic liquid OPLS-AA force field.

Novel developments in hydrogen storage, hydrogen activation and ionic liquids

Energy Technology Data Exchange (ETDEWEB)

Doroodian, Amir

2010-12-03

This dissertation is divided into three chapters. Recently, metal-free hydrogen activation using phosphorous compounds has been reported in science magazine. We have investigated the interaction between hydrogen and phosphorous compounds in presence of strong Lewis acids (chapter one). A new generation of metal-free hydrogen activation, using amines and strong Lewis acids with sterically demanding nature, was already developed in our group. Shortage of high storage capacity using large substitution to improve sterical effect led us to explore the amine borane derivatives, which are explained in chapter two. Due to the high storage capacity of hydrogen in aminoborane derivatives, we have explored these materials to extend hydrogen release. These compounds store hydrogen as proton and hydride on adjacent atoms or ions. These investigations resulted in developing hydrogen storage based on ionic liquids containing methyl guanidinium cation. Then we have continued to develop ionic liquids based on methyl guanidinium cation with different anions, such as tetrafluoro borate (chapter three). We have replaced these anions with transition metal anions to investigate hydrogen bonding and catalytic activity of ionic liquids. This chapter illustrates the world of ionic liquid as a green solvent for organic, inorganic and catalytic reactions and combines the concept of catalysts and solvents based on ionic liquids. The catalytic activity is investigated particularly with respect to the interaction with CO{sub 2}. (orig.)

Electrochemical functionalization of glassy carbon electrode by reduction of diazonium cations in protic ionic liquid

International Nuclear Information System (INIS)

Shul, Galyna; Ruiz, Carlos Alberto Castro; Rochefort, Dominic; Brooksby, Paula A.; Bélanger, Daniel

2013-01-01

Protic ionic liquid based on 2-methoxypyridine and trifluoroacetic acid was used as electrolyte for the functionalization of a glassy carbon electrode surface by electrochemical reduction of in situ generated 4-chlorobenzene diazonium and 4-nitrobenzene diazonium cations. The diazonium cations were synthesized in an electrochemical cell by reaction of the corresponding amines with NaNO 2 dissolved in protic ionic liquid. The resulting electrografted organic layers exhibit similar properties to those layers obtained by the derivatization from isolated diazonium salts dissolved in protic ionic liquid. Functionalized glassy carbon electrode surfaces were characterized by cyclic voltammetry, Fourier transform infrared and X-ray photoelectron spectroscopies. Atomic force microscopy thickness measurements revealed that, in our experimental conditions, the use of protic ionic liquid led to the formation of film with a thickness of about 1.5 nm. It is also demonstrated that the nitrobenzene chemisorbed on glassy carbon electrode or dissolved in protic ionic liquid undergoes electrochemical conversion to hydroxyaminobenzene

Thermo-Rheometric Studies of New Class Ionic Liquid Lubricants

Science.gov (United States)

Bakhtiyarov, Sayavur; Street, Kenneth; Scheiman, Daniel; van Dyke, Alan

2010-11-01

Due to their specific properties, such as small volatility, nonflammability, extreme thermal stability, low melting point, wide liquid range, and good miscibility with organic materials, ionic liquids attracted particular interest in various industrial processes. Recently, the unique properties of ionic liquids caught the attention of space tribologists. The traditional lubricating materials used in space have limited lifetimes in vacuum due to the catalytic degradation on metal surfaces, high vaporization at high temperatures, dewetting, and other disadvantages. The lubricants for the space applications must have vacuum stability, high viscosity index, low creep tendency, good elastohydrodynamic and boundary lubrication properties, radiation atomic oxygen resistance, optical or infrared transparency. Unfortunately, the properties such as heat flow, heat capacity, thermogravimetric weight loss, and non-linearity in the rheological behavior of the lubricants are not studied well for newly developed systems. These properties are crucial to analyzing thermodynamic and energy dissipative aspects of the lubrication process. In this paper we will present the rheological and heat and mass transfer measurements for the ionic liquid lubricants, their mixtures with and without additive.

Acidic Ionic Liquids.

Science.gov (United States)

Amarasekara, Ananda S

2016-05-25

Ionic liquid with acidic properties is an important branch in the wide ionic liquid field and the aim of this article is to cover all aspects of these acidic ionic liquids, especially focusing on the developments in the last four years. The structural diversity and synthesis of acidic ionic liquids are discussed in the introduction sections of this review. In addition, an unambiguous classification system for various types of acidic ionic liquids is presented in the introduction. The physical properties including acidity, thermo-physical properties, ionic conductivity, spectroscopy, and computational studies on acidic ionic liquids are covered in the next sections. The final section provides a comprehensive review on applications of acidic ionic liquids in a wide array of fields including catalysis, CO2 fixation, ionogel, electrolyte, fuel-cell, membrane, biomass processing, biodiesel synthesis, desulfurization of gasoline/diesel, metal processing, and metal electrodeposition.

Stern potential and Debye length measurements in dilute ionic solutions with electrostatic force microscopy.

Science.gov (United States)

Kumar, Bharat; Crittenden, Scott R

2013-11-01

We demonstrate the ability to measure Stern potential and Debye length in dilute ionic solution with atomic force microscopy. We develop an analytic expression for the second harmonic force component of the capacitive force in an ionic solution from the linearized Poisson-Boltzmann equation. This allows us to calibrate the AFM tip potential and, further, obtain the Stern potential of sample surfaces. In addition, the measured capacitive force is independent of van der Waals and double layer forces, thus providing a more accurate measure of Debye length.

Towards Molecular Dynamics Simulations of Chiral Room-Temperature Ionic Liquids

Czech Academy of Sciences Publication Activity Database

Lísal, Martin; Chval, Z.; Storch, Jan; Izák, Pavel

2014-01-01

Roč. 189, SI (2014), s. 85-94 ISSN 0167-7322 R&D Projects: GA ČR(CZ) GAP106/12/0569; GA MŠk LH12020 Institutional support: RVO:67985858 Keywords : chiral room-temperature ionic liquid * molecular dynamics simulation * non-polarizable fully flexible all-atom force field Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.515, year: 2014

The Effect of n vs. iso Isomerization on the Thermophysical Properties of Aromatic and Non-aromatic Ionic Liquids.

Science.gov (United States)

Rodrigues, Ana S M C; Almeida, Hugo F D; Freire, Mara G; Lopes-da-Silva, José A; Coutinho, João A P; Santos, Luís M N B F

2016-09-15

This work explores the n vs. iso isomerization effects on the physicochemical properties of different families of ionic liquids (ILs) with variable aromaticity and ring size. This study comprises the experimental measurements, in a wide temperature range, of the ILs' thermal behavior, heat capacities, densities, refractive indices, surface tensions, and viscosities. The results here reported show that the presence of the iso -alkyl group leads to an increase of the temperature of the glass transition, T g . The iso- pyrrolidinium (5 atoms ring cation core) and iso -piperidinium (6 atoms ring cation core) ILs present a strong differentiation in the enthalpy and entropy of melting. Non-aromatic ILs have higher molar heat capacities due to the increase of the atomic contribution, whereas it was not found any significant differentiation between the n and iso -alkyl isomers. A small increase of the surface tension was observed for the non-aromatic ILs, which could be related to their higher cohesive energy of the bulk, while the lower surface entropy observed for the iso isomers indicates a structural resemblance between the IL bulk and surface. The significant differentiation between ILs with a 5 and 6 atoms ring cation in the n -alkyl series (where 5 atoms ring cations have higher surface entropy) is an indication of a more efficient arrangement of the non-polar region at the surface in ILs with smaller cation cores. The ILs constituted by non-aromatic piperidinium cation, and iso -alkyl isomers were found to be the most viscous among the studied ILs due to their higher energy barriers for shear stress.

Study on intercalation of ionic liquid into montmorillonite and its property evaluation

International Nuclear Information System (INIS)

Takahashi, Chisato; Shirai, Takashi; Fuji, Masayoshi

2012-01-01

Present study report fabrication of a solid–liquid intercalated compound using montmorillonite and ionic liquid [IL; 1-Butyl-3-methylimidazolium tetrafluoroborate; ([BMIM][BF 4 ])]. The intercalation of IL into the interlayer of montmorillonite was revealed by swelling behavior measured by X-ray diffraction (XRD) and cation exchange capacity (CEC). The crystal swelling structure of intercalation compound was further evidenced by transmission electron microscope (TEM). From these results, the arrangement of [BMIM] + ions (cationic part of IL) into the unit layer were proposed. Furthermore, the montmorillonite showed electrical conductivity with the aid of IL. This demonstrates a successful attempt to fabricate a solid–liquid state nano-structure compound as possible transparent electrically conducting thin film. -- Highlights: ► Direct intercalation of ionic liquid into the montmorillonite was studied. ► The crystal swelling structure in liquid state was successfully characterized by TEM. ► We proposed the atomic arrangement of intercalated compound using ionic liquid. ► Ionic liquid is useful for fabricating an intercalated compound with electrical-conductivity.

Solid phase extraction of cadmium on 2-mercaptobenzothiazole loaded on sulfur powder in the medium of ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate and cold vapor generation-atomic absorption spectrometric determination

International Nuclear Information System (INIS)

Pourreza, N.; Ghanemi, K.

2010-01-01

A novel solid phase extractor for preconcentration of cadmium at ng L -1 levels has been developed. Cadmium ions were retained on a column packed with sulfur powder modified with 2-mercaptobenzothiazole (2-MBT) in the medium of 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim] + PF 6 - ) ionic liquid. The presence of ionic liquid during modification of sulfur enhanced the retention of cadmium ions on the column. The retained cadmium ions were eluted with 2 mol L -1 solution of HCl and measured by cold vapor generation-atomic absorption spectrometry (CVG-AAS). By using reaction cell-gas liquid separator (RC-GLS), gaseous cadmium vapors were produced and reached the atomic absorption spectrometer, instantaneously. The influence of different variables on both processes of solid phase extraction and CVG-AAS determination of cadmium ions was investigated. The calibration curve was linear in the range of 10-200 ng L -1 of cadmium in the initial solution with r = 0.9992 (n = 8) under optimum conditions. The limit of detection based on three times the standard deviation of the blank (3S b , n = 10) was 4.6 ng L -1 . The relative standard deviation (R.S.D.) of 25 and 150 ng L -1 of cadmium was 4.1 and 2.2% (n = 8), respectively. The procedure was validated by the analysis of a certified reference material (DORM-3), water and fish samples.

Atomic and electronic structures of an extremely fragile liquid.

Science.gov (United States)

Kohara, Shinji; Akola, Jaakko; Patrikeev, Leonid; Ropo, Matti; Ohara, Koji; Itou, Masayoshi; Fujiwara, Akihiko; Yahiro, Jumpei; Okada, Junpei T; Ishikawa, Takehiko; Mizuno, Akitoshi; Masuno, Atsunobu; Watanabe, Yasuhiro; Usuki, Takeshi

2014-12-18

The structure of high-temperature liquids is an important topic for understanding the fragility of liquids. Here we report the structure of a high-temperature non-glass-forming oxide liquid, ZrO2, at an atomistic and electronic level. The Bhatia-Thornton number-number structure factor of ZrO2 does not show a first sharp diffraction peak. The atomic structure comprises ZrO5, ZrO6 and ZrO7 polyhedra with a significant contribution of edge sharing of oxygen in addition to corner sharing. The variety of large oxygen coordination and polyhedral connections with short Zr-O bond lifetimes, induced by the relatively large ionic radius of zirconium, disturbs the evolution of intermediate-range ordering, which leads to a reduced electronic band gap and increased delocalization in the ionic Zr-O bonding. The details of the chemical bonding explain the extremely low viscosity of the liquid and the absence of a first sharp diffraction peak, and indicate that liquid ZrO2 is an extremely fragile liquid.

Development of an in situ solvent formation microextraction and preconcentration method based on ionic liquids for the determination of trace cobalt (II in water samples by flame atomic absorption spectrometry

Directory of Open Access Journals (Sweden)

Mohammad Reza Jamali

2017-02-01

Full Text Available A simple in situ solvent formation microextraction (ISFME methodology based on the application of ionic liquid (IL as an extractant solvent and sodium hexafluorophosphate (NaPF6 as an ion-pairing agent was proposed for the preconcentration of the trace levels of cobalt ions. In this method cobalt was complexed with 2-(5-bromo-2-pyridylazo-5-diethylaminophenol (5-Br-PADAP and extracted into an ionic liquid phase. After phase separation, the enriched analyte in the final solution is determined by flame atomic absorption spectrometry (FAAS. Some effective factors that influence the microextraction efficiency were investigated and optimized. Under the optimum experimental conditions, the limit of detection and the enrichment factor were 0.97 μg L−1 and 50, respectively. The relative standard deviation (R.S.D. was obtained as 2.4%. The proposed method was assessed through the analysis of certified reference water and recovery experiments.

Room temperature ionic liquids enhanced the speciation of Cr(VI) and Cr(III) by hollow fiber liquid phase microextraction combined with flame atomic absorption spectrometry

Energy Technology Data Exchange (ETDEWEB)

Zeng, Chujie, E-mail: cjzeng@126.com [Department of Chemistry and Material, Yulin Normal College, Yulin, Guangxi 537000 (China); Lin, Yao; Zhou, Neng; Zheng, Jiaoting; Zhang, Wei [Department of Chemistry and Material, Yulin Normal College, Yulin, Guangxi 537000 (China)

2012-10-30

Highlights: Black-Right-Pointing-Pointer First reported enhancement effect of RTILs in HF-LPME for the speciation of chromium. Black-Right-Pointing-Pointer The addition of RTILs led to 3.5 times improvement of the sensitivity of Cr(VI). Black-Right-Pointing-Pointer The proposed method is a simplicity, sensitivity, low cost, green method. - Abstract: A new method for the speciation of Cr(VI) and Cr(III) based on enhancement effect of room temperature ionic liquids (RTILs) for hollow fiber liquid phase microextraction (HF-LPME) combined with flame atomic absorption spectrometry (FAAS) was developed. Room temperature ionic liquids (RTILs) and diethyldithiocarbamate (DDTC) were used enhancement reagents and chelating reagent, respectively. The addition of room temperature ionic liquids led to 3.5 times improvement in the determination of Cr(VI). In this method, Cr(VI) reacts with DDTC yielding a hydrophobic complex, which is subsequently extracted into the lumen of hollow fiber, whereas Cr(III) is remained in aqueous solutions. The extraction organic phase was injected into FAAS for the determination of Cr(VI). Total Cr concentration was determined after oxidizing Cr(III) to Cr(VI) in the presence of KMnO{sub 4} and using the extraction procedure mentioned above. Cr(III) was calculated by subtracting of Cr(VI) from the total Cr. Under optimized conditions, a detection limit of 0.7 ng mL{sup -1} and an enrichment factor of 175 were achieved. The relative standard deviation (RSD) was 4.9% for Cr(VI) (40 ng mL{sup -1}, n = 5). The proposed method was successfully applied to the speciation of chromium in natural water samples with satisfactory results.

Room temperature ionic liquids enhanced the speciation of Cr(VI) and Cr(III) by hollow fiber liquid phase microextraction combined with flame atomic absorption spectrometry

International Nuclear Information System (INIS)

Zeng, Chujie; Lin, Yao; Zhou, Neng; Zheng, Jiaoting; Zhang, Wei

2012-01-01

Highlights: ► First reported enhancement effect of RTILs in HF-LPME for the speciation of chromium. ► The addition of RTILs led to 3.5 times improvement of the sensitivity of Cr(VI). ► The proposed method is a simplicity, sensitivity, low cost, green method. - Abstract: A new method for the speciation of Cr(VI) and Cr(III) based on enhancement effect of room temperature ionic liquids (RTILs) for hollow fiber liquid phase microextraction (HF-LPME) combined with flame atomic absorption spectrometry (FAAS) was developed. Room temperature ionic liquids (RTILs) and diethyldithiocarbamate (DDTC) were used enhancement reagents and chelating reagent, respectively. The addition of room temperature ionic liquids led to 3.5 times improvement in the determination of Cr(VI). In this method, Cr(VI) reacts with DDTC yielding a hydrophobic complex, which is subsequently extracted into the lumen of hollow fiber, whereas Cr(III) is remained in aqueous solutions. The extraction organic phase was injected into FAAS for the determination of Cr(VI). Total Cr concentration was determined after oxidizing Cr(III) to Cr(VI) in the presence of KMnO 4 and using the extraction procedure mentioned above. Cr(III) was calculated by subtracting of Cr(VI) from the total Cr. Under optimized conditions, a detection limit of 0.7 ng mL −1 and an enrichment factor of 175 were achieved. The relative standard deviation (RSD) was 4.9% for Cr(VI) (40 ng mL −1 , n = 5). The proposed method was successfully applied to the speciation of chromium in natural water samples with satisfactory results.

Stern potential and Debye length measurements in dilute ionic solutions with electrostatic force microscopy

International Nuclear Information System (INIS)

Kumar, Bharat; Crittenden, Scott R

2013-01-01

We demonstrate the ability to measure Stern potential and Debye length in dilute ionic solution with atomic force microscopy. We develop an analytic expression for the second harmonic force component of the capacitive force in an ionic solution from the linearized Poisson–Boltzmann equation. This allows us to calibrate the AFM tip potential and, further, obtain the Stern potential of sample surfaces. In addition, the measured capacitive force is independent of van der Waals and double layer forces, thus providing a more accurate measure of Debye length. (paper)

Scaling properties of fracture surfaces on glass strengthened by ionic exchange

International Nuclear Information System (INIS)

Garza-Mendez, F.J.; Hinojosa-Rivera, M.; Gomez, I.; Sanchez, E.M.

2007-01-01

In this work the results of the statistical topometric analysis of fracture surfaces of soda-lime-silica glass with and without ionic exchange treatment are reported. In this case, the mechanism of substitution is K + -Na + . atomic force microscopy (AFM) was employed to record the topometric data from the fracture surface. The roughness exponent (ζ) and the correlation length (ξ) were calculated by the variable bandwidth method. The analysis for both glasses (subjected and non-subjected to ionic exchange) for ζ shows a value ∼0.8, this value agrees well with that reported in the literature for rapid crack propagation in a variety of materials. The correlation length shows different values for each condition. These results, along with those of microhardness indentations suggest that the self-affine correlation length is influenced by the complex interactions of the stress field of microcracks with that resulting from the collective behavior of the point defects introduced by the strengthening mechanism of ionic exchange

Photoelectron spectroscopy of heavy atoms and molecules

International Nuclear Information System (INIS)

White, M.G.

1979-07-01

The importance of relativistic interactions in the photoionization of heavy atoms and molecules has been investigated by the technique of photoelectron spectroscopy. In particular, experiments are reported which illustrate the effects of the spin-orbit interaction in the neutral ground state, final ionic states and continuum states of the photoionization target

Electrochemical behavior of ionically crosslinked polyampholytic gel electrolytes

International Nuclear Information System (INIS)

Chen Wanyu; Tang Haitao; Ou Ziwei; Wang Hong; Yang Yajiang

2007-01-01

An ionic complex of anionic and cationic monomers was obtained by protonation of (N,N-diethylamino)ethylmethacrylate (DEA) with acrylic acid (AAc). Free radical copolymerization of the ionic complex and acrylamide (AAm), yielded the ionically crosslinked polyampholytic gel electrolytes [poly(AAc-DEA-AAm), designated as PADA] using two types of organic solvents containing a lithium salt. The PADA gel electrolyte exhibited good thermal stability shown by the DSC thermogram. The impedance analysis at temperatures ranging from -30 to 75 deg. C indicated that the ionic conductivities of the PADA gel electrolytes were rather close to those of liquid electrolytes. The temperature dependence of the ionic conductivities was found to be in accord with the Arrhenius equation. Moreover, the ionic conductivities of PADA gel electrolytes increased with an increase of the molar ratios of cationic/anionic monomers. The ionic conductivities of PADA gels prepared in solvent mixtures of propylene carbonate, ethyl methyl ether and dioxolane (3:1:1, v/v) were higher than those of PADA gels prepared in propylene carbonate only. Significantly, the ionic conductivities of two kinds of PADA gel electrolytes were in the range of 10 -3 and 10 -4 S cm -1 even at -30 deg. C. The electrochemical windows of PADA gel electrolytes measured by cyclic voltammetry were in the range from -1 V to 4.5 V

Predictive QSAR modelling of algal toxicity of ionic liquids and its interspecies correlation with Daphnia toxicity.

Science.gov (United States)

Roy, Kunal; Das, Rudra Narayan; Popelier, Paul L A

2015-05-01

Predictive toxicology using chemometric tools can be very useful in order to fill the data gaps for ionic liquids (ILs) with limited available experimental toxicity information, in view of their growing industrial uses. Though originally promoted as green chemicals, ILs have now been shown to possess considerable toxicity against different ecological endpoints. Against this background, quantitative structure-activity relationship (QSAR) models have been developed here for the toxicity of ILs against the green algae Scenedesmus vacuolatus using computed descriptors with definite physicochemical meaning. The final models emerged from E-state indices, extended topochemical atom (ETA) indices and quantum topological molecular similarity (QTMS) indices. The developed partial least squares models support the established mechanism of toxicity of ionic liquids in terms of a surfactant action of cations and chaotropic action of anions. The models have been developed within the guidelines of the Organization of Economic Co-operation and Development (OECD) for regulatory QSAR models, and they have been validated both internally and externally using multiple strategies and also tested for applicability domain. A preliminary attempt has also been made, for the first time, to develop interspecies quantitative toxicity-toxicity relationship (QTTR) models for the algal toxicity of ILs with Daphnia toxicity, which should be interesting while predicting toxicity of ILs for an endpoint when the data for the other are available.

Crystal structure of dimethylformamidium bis(trifluoromethanesulfonyl)amide: an ionic liquid

OpenAIRE

Allan Jay P. Cardenas; Molly O'Hagan

2016-01-01

At 100?K, the title mol?ecular salt, C3H8NO+?C2F6NO4S2 ?, has ortho?rhom?bic (P212121) symmetry; the amino H atom of bis?(tri?fluoro?methane?sulfon?yl)amine (HNTf2) was transferred to the basic O atom of di?methyl?formamide (DMF) when the ionic liquid components were mixed. The structure displays an O?H?N hydrogen bond, which links the cation to the anion, which is reinforced by a non-conventional C?H?O inter?action, generating an R 2 2(7) loop. A further very weak C?H?O inter?action generate...

Thermophysical properties of hydroxyl ammonium ionic liquids

International Nuclear Information System (INIS)

Kurnia, K.A.; Wilfred, C.D.; Murugesan, T.

2009-01-01

The thermophysical properties of hydroxyl ammonium ionic liquids: density ρ, T = (293.15 to 363.15) K; dynamic viscosity η, T = (298.2 to 348.2) K; and refractive indices n D , T = (293.15 to 333.15) K have been measured. The coefficients of thermal expansion α, values were calculated from the experimental density results using an empirical correlation for T = (293.15 to 363.15) K. The variation of volume expansion of ionic liquids studied was found to be independent of temperature within the range covered in the present work. The thermal decomposition temperature 'T d ' for all the six hydroxyl ammonium ionic liquids is also investigated using thermogravimetric analyzer (TGA)

Surface science and model catalysis with ionic liquid-modified materials.

Science.gov (United States)

Steinrück, H-P; Libuda, J; Wasserscheid, P; Cremer, T; Kolbeck, C; Laurin, M; Maier, F; Sobota, M; Schulz, P S; Stark, M

2011-06-17

Materials making use of thin ionic liquid (IL) films as support-modifying functional layer open up a variety of new possibilities in heterogeneous catalysis, which range from the tailoring of gas-surface interactions to the immobilization of molecularly defined reactive sites. The present report reviews recent progress towards an understanding of "supported ionic liquid phase (SILP)" and "solid catalysts with ionic liquid layer (SCILL)" materials at the microscopic level, using a surface science and model catalysis type of approach. Thin film IL systems can be prepared not only ex-situ, but also in-situ under ultrahigh vacuum (UHV) conditions using atomically well-defined surfaces as substrates, for example by physical vapor deposition (PVD). Due to their low vapor pressure, these systems can be studied in UHV using the full spectrum of surface science techniques. We discuss general strategies and considerations of this approach and exemplify the information available from complementary methods, specifically photoelectron spectroscopy and surface vibrational spectroscopy. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Theoretical study for pyridinium-based ionic liquid 1-ethylpyridinium trifluoroacetate: synthesis mechanism, electronic structure, and catalytic reactivity.

Science.gov (United States)

Zhu, Xueying; Cui, Peng; Zhang, Dongju; Liu, Chengbu

2011-07-28

By performing density functional theory calculations, we have studied the synthesis mechanism, electronic structure, and catalytic reactivity of a pyridinium-based ionic liquid, 1-ethylpyridinium trifluoroacetate ([epy](+)[CF(3)COO](-)). It is found that the synthesis of the pyridinium salt follows a S(N)2 mechanism. The electronic structural analyses show that multiple H bonds are generally involved in the pyridinium-based ionic liquid, which may play a decisive role for stabilizing the ionic liquid. The cation-anion interaction mainly involves electron transfer between the lone pair of the oxygen atom in the anion and the antibonding orbital of the C*-H bond (C* denotes the carbon atom at the ortho-position of nitrogen atom in the cation). This present work has also given clearly the catalytic mechanism of [epy](+)[CF(3)COO](-) toward to the Diels-Alder (D-A) reaction of acrylonitrile with 2-methyl-1,3-butadiene. Both the cation and anion are shown to play important roles in promoting the D-A reaction. The cation [epy](+), as a Lewis acid, associates the C≡N group by C≡N···H H bond to increase the polarity of the C═C double bond in acrylonitrile, while the anion CF(3)COO(-) links with the methyl group in 2-methyl-1,3-butadiene by C-H···O H bond, which weakens the electron-donating capability of methyl and thereby lowers the energy barrier of the D-A reaction. The present results are expected to provide valuable information for the design and application of pyridinium-based ionic liquids. © 2011 American Chemical Society

Theoretical study of atomic structure of Zionic excited state populations in a hot plasma and population inversions

International Nuclear Information System (INIS)

Guennou, Helene.

1983-05-01

This thesis presents a theoretical method for atomic-structure calculations (energy levels, wave functions, oscillator strengths): it is a modified Hartree-Fock method including the spin-orbit interaction in the variationnal process. Two applications are first described: one concerning the resonance lines of the Krypton isoelectronic sequence, the other having for purpose the interpretation of Lsub(α) and Lsub(β) satellites in Copper. A description is made of an original collisional-radiative model, which makes use of the preceding method, and allows to calculate the populations of a great number of ionic excited levels in a plasma. This model is used in a detailed study of the Al 10+ Lithium -like ion spectrum. It is able to explain the apparition of inversion populations for some special electronic densities and temperatures, for example between the levels corresponding to the transitions observed at 103.8, 105.7 and 154.7 A [fr

Iron species determination by task-specific ionic liquid-based in situ solvent formation dispersive liquid-liquid microextraction combined with flame atomic absorption spectrometry.

Science.gov (United States)

Sadeghi, Susan; Ashoori, Vahid

2017-10-01

The task-specific ionic liquid (TSIL) of 1-ethyl-3-methylimidazolium bromide functionalized with 8-hydroxyquinoline was used as a chelating agent and extracting solvent for dispersive liquid-liquid microextraction and subsequent determination of Fe(III) by flame atomic absorption spectrometry. The in situ solvent formation of TSIL using KPF 6 provided the desired water-immiscible ionic liquid. The total Fe concentration could be determined after pre-oxidation of Fe(II) to Fe(III). Various factors affecting the proposed extraction procedure were optimized. The proposed analytical conditions were: sample pH 5, TSIL amount 0.3% (w/v), KPF 6 amount 0.15% (w/v), anti-sticking 0.1% (w/v) and salt concentration 5% (w/v). Under optimal conditions, the linear dynamic ranges for Fe(III) and total Fe were 20-80 and 20-110 ng mL -1 , respectively, with a detection limit of 6.9 ng mL -1 for Fe(III) and relative standard deviation of 2.2%. The proposed method was successfully applied to the determination of trace Fe(III) in water (underground, tap, refined water and artificial sea water) and beverage (apple, tomato, and tea) samples. The developed method offers advantages such as simplicity, ease of operation, and extraction of Fe(III) from aqueous solutions without the use of organic solvent. It was successfully applied for iron speciation in different real samples. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Electrochemical properties of novel ionic liquids for electric double layer capacitor applications

International Nuclear Information System (INIS)

Sato, Takaya; Masuda, Gen; Takagi, Kentaro

2004-01-01

An aliphatic quaternary ammonium salt which has a methoxyethyl group on the nitrogen atom formed an ionic liquid (room temperature molten salt) when combined with the tetrafluoroborate (BF 4 - ) and bis(trifluoromethylsulfonyl)imide [TFSI; (CF 3 SO 2 ) 2 N - ] anions. The limiting oxidation and reduction potentials, specific conductivity, and some other physicochemical properties of the novel ionic liquids, N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium tetrafluoroborate (DEME-BF 4 ) and DEME-TFSI have been evaluated and compared with those of 1-ethyl-3-methylimidazolium tetrafluoroborate. DEME-BF 4 is a practically useful ionic liquid for electrochemical capacitors as it has a quite wide potential window (6.0 V) and high ionic conductivity (4.8 mS cm -1 at 25 deg. C). We prepared an electric double layer capacitor (EDLC) composed of a pair of activated carbon electrodes and DEME-BF 4 as the electrolyte. This EDLC (working voltage ∼2.5 V) has both, a higher capacity above room temperature and a better charge-discharge cycle durability at 100 deg. C when compared to a conventional EDLC using an organic liquid electrolyte such as a tetraethylammonium tetrafluoroborate in propylene carbonate

Selective Ionic Transport Pathways in Phosphorene.

Science.gov (United States)

Nie, Anmin; Cheng, Yingchun; Ning, Shoucong; Foroozan, Tara; Yasaei, Poya; Li, Wen; Song, Boao; Yuan, Yifei; Chen, Lin; Salehi-Khojin, Amin; Mashayek, Farzad; Shahbazian-Yassar, Reza

2016-04-13

Despite many theoretical predictions indicating exceptionally low energy barriers of ionic transport in phosphorene, the ionic transport pathways in this two-dimensional (2D) material has not been experimentally demonstrated. Here, using in situ aberration-corrected transmission electron microscopy (TEM) and density functional theory, we studied sodium ion transport in phosphorene. Our high-resolution TEM imaging complemented by electron energy loss spectroscopy demonstrates a precise description of anisotropic sodium ions migration along the [100] direction in phosphorene. This work also provides new insight into the effect of surface and the edge sites on the transport properties of phosphorene. According to our observation, the sodium ion transport is preferred in zigzag edge rather than the armchair edge. The use of this highly selective ionic transport property may endow phosphorene with new functionalities for novel chemical device applications.

Determination of trace elements in atomic absorption spectrophotometry. Study of the atomic cloud and atom generator. Application to the measurement of physical quantities

International Nuclear Information System (INIS)

Hircq, Bernard.

1976-06-01

After the description of the absorption cell the principal parameters are studied: argon flow rate in the cell, atomization temperature, cell geometry etc. The technique is applied to the measurement of impurities in uranium after deposition on a carbon filament. The atomic concentration distribution and the dimensions of the cloud generated by a graphite filament are then studied along the axes parallel to the filament and as a function of the various experimental parameters. From the determination of the cloud elevation rate it is possible to calculate the absolute atomic concentration, which allows certain physical quantities to be evaluated: oscillator force, Lorentz Widening, diffusion coefficient... The size and penetration depth of the deposit are then determined with an ionic microprobe and the distribution with a Castaing microprobe. The chemical transformations undergone by the uranium matrix during the heat cycles are studied by the X-ray method [fr

SISGR: Physical Chemistry of Reaction Dynamics in Ionic Liquids

Energy Technology Data Exchange (ETDEWEB)

Blank, David [Univ. of Minnesota, Minneapolis, MN (United States)

2017-10-30

Room temperature ionic liquids (RTILs) are liquids made up of atomic and molecular ions. This is in contrast with more common liquids, such as water, that are made up of neutral molecules. The additional charges on the atoms and molecules can alter the properties of these liquids, for example they tend to have a very high vapor pressure and the ability to shield charge in electronic devices. For these and other reasons RTILs have recently been deployed in a number of applications that involve production of free electrons in the liquid, such as batteries, capacitors, nuclear power plants, and solar cells. Electrons tend to be very reactive, and understanding their behaviour in these liquids is important for the future design of ionic liquids to be employed in these environments. This study investigated the behavior of electrons generated in RTILs by pulses of ultraviolet light, including how long they survive, and how reactive they are with the both the surrounding liquid and impurities in the liquid. The ionic liquid studied was one of the most commonly used, called N-alkyl-N-methyl-pyrrolidinium bistriflimide. What the study revealed was that the majority of the electrons initially created, about 96%, had a very short lifetime of less than one picosecond (10-12 second) due to a process called geminate recombination. The study also demonstrated that the electrons are very reactive at the moment they are detached from the molecules in the liquid by light, but that they relax very quickly and lose almost all of their reactivity in much less than one picosecond. The short lifetime and rapid loss of reactivity both serve as important mechanisms that protect the liquid from radiolytic damage.

SO2 Solvation in the 1-Ethyl-3-Methylimidazolium Thiocyanate Ionic Liquid by Incorporation into the Extended Cation-Anion Network.

Science.gov (United States)

Firaha, Dzmitry S; Kavalchuk, Mikhail; Kirchner, Barbara

We have carried out an ab initio molecular dynamics study on the sulfur dioxide (SO 2 ) solvation in 1-ethyl-3-methylimidazolium thiocyanate for which we have observed that both cations and anions play an essential role in the solvation of SO 2 . Whereas, the anions tend to form a thiocyanate- and much less often an isothiocyanate-SO 2 adduct, the cations create a "cage" around SO 2 with those groups of atoms that donate weak interactions like the alkyl hydrogen atoms as well as the heavy atoms of the [Formula: see text]-system. Despite these similarities between the solvation of SO 2 and CO 2 in ionic liquids, an essential difference was observed with respect to the acidic protons. Whereas CO 2 avoids accepting hydrogen bonds form the acidic hydrogen atoms of the cations, SO 2 can from O(SO 2 )-H(cation) hydrogen bonds and thus together with the strong anion-adduct it actively integrates in the hydrogen bond network of this particular ionic liquid. The fact that SO 2 acts in this way was termed a linker effect by us, because the SO 2 can be situated between cation and anion operating as a linker between them. The particular contacts are the H(cation)[Formula: see text]O(SO 2 ) hydrogen bond and a S(anion)-S(SO 2 ) sulfur bridge. Clearly, this observation provides a possible explanation for the question of why the SO 2 solubility in these ionic liquids is so high.

Joint General Atomic-TAERF fusion program

Energy Technology Data Exchange (ETDEWEB)

Kerst, D W [John Jay Hopkins Laboratory for Pure and Applied Science, General Atomic Division of General Dynamics Corporation, San Diego, CA (United States)

1958-07-01

The experimental work has consisted of several parts: the study of charge exchange in hydrogen ionic and atomic collisions, the study of some linear pinch discharge systems with high stabilizing axial magnetic fields, developments on a small scale for a large toroidal geometry, and experiments with various diagnostic methods, including electrical, optical, and shock-tube methods. The experiments on atomic collisions have consisted of measurements of cross sections for the ionization, the excitation of Lyman-alpha radiation, and elastic scattering for the case of electron bombardment. In addition, charge-exchange cross sections between deuterons and deuterium atoms have been measured. The calculations of Dalgarno and Yadav, using a perturbed stationary-state approximation are close to the experimental results which show a very large cross section for charge exchange.

Fullerol ionic fluids

KAUST Repository

Fernandes, Nikhil; Dallas, Panagiotis; Rodriguez, Robert; Bourlinos, Athanasios B.; Georgakilas, Vasilios; Giannelis, Emmanuel P.

2010-01-01

®). The ionic fluid was compared to a control synthesized by mixing the partially protonated form (sodium form) of the fullerols with the same oligomeric amine in the same ratio as in the ionic fluids (20 wt% fullerol). In the fullerol fluid the ionic bonding

Atomic structures of Cd Te and Cd Se (110) surfaces

International Nuclear Information System (INIS)

Watari, K.; Ferraz, A.C.

1996-01-01

Results are reported based on the self-consistent density-functional theory, within the local-density approximation using ab-initio pseudopotentials of clean Cd Te and Cd Se (110) surfaces. We analyzed the trends for the equilibrium atomic structures, and the variations of the bond angles at the II-VI (110). The calculations are sensitive to the ionicity of the materials and the results are in agreement with the arguments which predict that the relaxed zinc-blend (110) surfaces should depend on ionicity. (author). 17 refs., 1 figs., 3 tabs

DFT reactivity indices in confined many-electron atoms + ∫

Indian Academy of Sciences (India)

Unknown

Functional Theory (DFT) based global descriptors of chemical reactivity for atoms .... interesting due to its utility as a model in the wide variety of applications ... hydrogen atom at Rc = 2⋅0 au is expected to correspond to the energy value of ...

Fullerol ionic fluids

KAUST Repository

Fernandes, Nikhil

2010-01-01

We report for the first time an ionic fluid based on hydroxylated fullerenes (fullerols). The ionic fluid was synthesized by neutralizing the fully protonated fullerol with an amine terminated polyethylene/polypropylene oxide oligomer (Jeffamine®). The ionic fluid was compared to a control synthesized by mixing the partially protonated form (sodium form) of the fullerols with the same oligomeric amine in the same ratio as in the ionic fluids (20 wt% fullerol). In the fullerol fluid the ionic bonding significantly perturbs the thermal transitions and melting/crystallization behavior of the amine. In contrast, both the normalized heat of fusion and crystallization of the amine in the control are similar to those of the neat amine consistent with a physical mixture of the fullerols/amine with minimal interactions. In addition to differences in thermal behavior, the fullerol ionic fluid exhibits a complex viscoelastic behavior intermediate between the neat Jeffamine® (liquid-like) and the control (solid-like). © 2010 The Royal Society of Chemistry.

Fullerol ionic fluids

Science.gov (United States)

Fernandes, Nikhil; Dallas, Panagiotis; Rodriguez, Robert; Bourlinos, Athanasios B.; Georgakilas, Vasilios; Giannelis, Emmanuel P.

2010-09-01

We report for the first time an ionic fluid based on hydroxylated fullerenes (fullerols). The ionic fluid was synthesized by neutralizing the fully protonated fullerol with an amine terminated polyethylene/polypropylene oxide oligomer (Jeffamine®). The ionic fluid was compared to a control synthesized by mixing the partially protonated form (sodium form) of the fullerols with the same oligomeric amine in the same ratio as in the ionic fluids (20 wt% fullerol). In the fullerol fluid the ionic bonding significantly perturbs the thermal transitions and melting/crystallization behavior of the amine. In contrast, both the normalized heat of fusion and crystallization of the amine in the control are similar to those of the neat amine consistent with a physical mixture of the fullerols/amine with minimal interactions. In addition to differences in thermal behavior, the fullerol ionic fluid exhibits a complex viscoelastic behavior intermediate between the neat Jeffamine® (liquid-like) and the control (solid-like).

Correlations between phase behaviors and ionic conductivities of (ionic liquid + alcohol) systems

International Nuclear Information System (INIS)

Park, Nam Ku; Bae, Young Chan

2010-01-01

To understand the basic properties of ionic liquids (ILs), we examined the phase behavior and ionic conductivity characteristics using various compositions of different ionic liquids (1-ethyl-3-methylimidazolium hexafluorophosphate [emim] [PF6] and 1-benzyl-3-methylimidazolium hexafluorophosphate [bzmim] [PF6]) in several different alcohols (ethanol, propanol, 1-butanol, 2-butanol, and hexanol). We conducted a systematic study of the impact of different factors on the phase behavior of imidazolium-based ionic liquids in alcohols. Using a new experimental method with a liquid electrolyte system, we observed that the ionic conductivity of the ionic liquid/alcohol was sensitive to the surrounding temperature. We employed Chang et al.'s thermodynamic model [Chang et al. (1997, 1998) ] based on the lattice model. The obtained co-ordinated unit parameter from this model was used to describe the phase behavior and ionic conductivities of the given system. Good agreement with experimental data of various alcohol and ILs systems was obtained in the range of interest.

The shape-memory effect in ionic elastomers: fixation through ionic interactions.

Science.gov (United States)

González-Jiménez, Antonio; Malmierca, Marta A; Bernal-Ortega, Pilar; Posadas, Pilar; Pérez-Aparicio, Roberto; Marcos-Fernández, Ángel; Mather, Patrick T; Valentín, Juan L

2017-04-19

Shape-memory elastomers based on a commercial rubber cross-linked by both ionic and covalent bonds have been developed. The elastomeric matrix was a carboxylated nitrile rubber (XNBR) vulcanized with magnesium oxide (MgO) providing ionic interactions that form hierarchical structures. The so-named ionic transition is used as the unique thermal transition responsible for the shape-memory effect (SME) in these elastomers. These ionic interactions fix the temporary shape due to their behavior as dynamic cross-links with temperature changes. Covalent cross-links were incorporated with the addition of different proportions of dicumyl peroxide (DCP) to the ionic elastomer to establish and recover the permanent shape. In this article, the SME was modulated by modifying the degree of covalent cross-linking, while keeping the ionic contribution constant. In addition, different programming parameters, such as deformation temperature, heating/cooling rate, loading/unloading rate and percentage of tensile strain, were evaluated for their effects on shape-memory behavior.

Is the boundary layer of an ionic liquid equally lubricating at higher temperature?

Science.gov (United States)

Hjalmarsson, Nicklas; Atkin, Rob; Rutland, Mark W

2016-04-07

Atomic force microscopy has been used to study the effect of temperature on normal forces and friction for the room temperature ionic liquid (IL) ethylammonium nitrate (EAN), confined between mica and a silica colloid probe at 25 °C, 50 °C, and 80 °C. Force curves revealed a strong fluid dynamic influence at room temperature, which was greatly reduced at elevated temperatures due to the reduced liquid viscosity. A fluid dynamic analysis reveals that bulk viscosity is manifested at large separation but that EAN displays a nonzero slip, indicating a region of different viscosity near the surface. At high temperatures, the reduction in fluid dynamic force reveals step-like force curves, similar to those found at room temperature using much lower scan rates. The ionic liquid boundary layer remains adsorbed to the solid surface even at high temperature, which provides a mechanism for lubrication when fluid dynamic lubrication is strongly reduced. The friction data reveals a decrease in absolute friction force with increasing temperature, which is associated with increased thermal motion and reduced viscosity of the near surface layers but, consistent with the normal force data, boundary layer lubrication was unaffected. The implications for ILs as lubricants are discussed in terms of the behaviour of this well characterised system.

Ionic liquids behave as dilute electrolyte solutions

Science.gov (United States)

Gebbie, Matthew A.; Valtiner, Markus; Banquy, Xavier; Fox, Eric T.; Henderson, Wesley A.; Israelachvili, Jacob N.

2013-01-01

We combine direct surface force measurements with thermodynamic arguments to demonstrate that pure ionic liquids are expected to behave as dilute weak electrolyte solutions, with typical effective dissociated ion concentrations of less than 0.1% at room temperature. We performed equilibrium force–distance measurements across the common ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C4mim][NTf2]) using a surface forces apparatus with in situ electrochemical control and quantitatively modeled these measurements using the van der Waals and electrostatic double-layer forces of the Derjaguin–Landau–Verwey–Overbeek theory with an additive repulsive steric (entropic) ion–surface binding force. Our results indicate that ionic liquids screen charged surfaces through the formation of both bound (Stern) and diffuse electric double layers, where the diffuse double layer is comprised of effectively dissociated ionic liquid ions. Additionally, we used the energetics of thermally dissociating ions in a dielectric medium to quantitatively predict the equilibrium for the effective dissociation reaction of [C4mim][NTf2] ions, in excellent agreement with the measured Debye length. Our results clearly demonstrate that, outside of the bound double layer, most of the ions in [C4mim][NTf2] are not effectively dissociated and thus do not contribute to electrostatic screening. We also provide a general, molecular-scale framework for designing ionic liquids with significantly increased dissociated charge densities via judiciously balancing ion pair interactions with bulk dielectric properties. Our results clear up several inconsistencies that have hampered scientific progress in this important area and guide the rational design of unique, high–free-ion density ionic liquids and ionic liquid blends. PMID:23716690

Predictive model for ionic liquid extraction solvents for rare earth elements

International Nuclear Information System (INIS)

Grabda, Mariusz; Oleszek, Sylwia; Panigrahi, Mrutyunjay; Kozak, Dmytro; Shibata, Etsuro; Nakamura, Takashi; Eckert, Franck

2015-01-01

The purpose of our study was to select the most effective ionic liquid extraction solvents for dysprosium (III) fluoride using a theoretical approach. Conductor-like Screening Model for Real Solvents (COSMO-RS), based on quantum chemistry and the statistical thermodynamics of predefined DyF 3 -ionic liquid systems, was applied to reach the target. Chemical potentials of the salt were predicted in 4,400 different ionic liquids. On the base of these predictions set of ionic liquids’ ions, manifesting significant decrease of the chemical potentials, were selected. Considering the calculated physicochemical properties (hydrophobicity, viscosity) of the ionic liquids containing these specific ions, the most effective extraction solvents for liquid-liquid extraction of DyF 3 were proposed. The obtained results indicate that the COSMO-RS approach can be applied to quickly screen the affinity of any rare earth element for a large number of ionic liquid systems, before extensive experimental tests

Influence of ionic parameters on Auger emission by aluminium, induced by medium energy ions (2 to 5 keV)

International Nuclear Information System (INIS)

Celier, Dominique

1987-01-01

This research thesis reports the study of excitation collision mechanisms of metal atoms under irradiation by electrons with energy lower than or equal to 5 keV. After having outlined why this energy range is interesting, and indicated the different aluminium single crystals used in this study, the author describes the main involved emission phenomena related to the series of collisions due to emissions of different particles (electrons, photons, neutral or ionized atoms, backscattered primary ions). In the second part, the author recalls the characteristics of an Auger emission induced by ionic bombardment. Then, he presents the experimental installation which has been calibrated in order to allow the comparison of spectra induced under irradiations with different characteristics. Experimental results are reported and discussed. The cascade of binary shocks has also been examined. The scattering integral has been computed for several simple cases of collision, and allowed the definition of different conditions of excitation and ejection of excited atoms, depending on the fact that the ionizing shock is asymmetric or symmetric [fr

Molecular interactions and thermal transport in ionic liquids with carbon nanomaterials.

Science.gov (United States)

França, João M P; Nieto de Castro, Carlos A; Pádua, Agílio A H

2017-07-05

We used molecular dynamics simulation to study the effect of suspended carbon nanomaterials, nanotubes and graphene sheets, on the thermal conductivity of ionic liquids, an issue related to understanding the properties of nanofluids. One important aspect that we developed is an atomistic model of the interactions between the organic ions and carbon nanomaterials, so we did not rely on existing force fields for small organic molecules or assume simple combining rules to describe the interactions at the liquid/material interface. Instead, we used quantum calculations with a density functional suitable for non-covalent interactions to parameterize an interaction model, including van der Waals terms and also atomic partial charges on the materials. We fitted a n-m interaction potential function with n values of 9 or 10 and m values between 5 and 8, so a 12-6 Lennard-Jones function would not fit the quantum calculations. For the atoms of ionic liquids and carbon nanomaterials interacting among themselves, we adopted existing models from the literature. We studied the imidazolium ionic liquids [C 4 C 1 im][SCN], [C 4 C 1 im][N(CN) 2 ], [C 4 C 1 im][C(CN) 3 ] and [C 4 C 1 im][(CF 3 SO 2 ) 2 N]. Attraction is stronger for cations (than for anions) above and below the π-system of the nanomaterials, whereas anions show stronger attraction for the hydrogenated edges. The ordering of ions around and inside (7,7) and (10,10) single-walled nanotubes, and near a stack of graphene sheets, was analysed in terms of density distribution functions. We verified that anions are found, as well as cations, in the first interfacial layer interacting with the materials, which is surprising given the interaction potential surfaces. The thermal conductivity of the ionic liquids and of composite systems containing one nanotube or one graphene stack in suspension was calculated using non-equilibrium molecular dynamics. Thermal conductivity was calculated along the axis of the nanotube and

Clinical trial of non-ionic contrast media -comparison of efficacy and safety between non-ionic iopromide (Ultravist) and ionic contrast media-

International Nuclear Information System (INIS)

Lee, Ghi Jai; Kim, Seung Hyup; Park, Jae Hyung; Chang, Kee Hyun; Han, Man Chung; Kim, Chu Wan

1988-01-01

Non-ionic contrast media, iopromide (Ultravist) was compared with ioxitalamate (Telebrix) and/or ioxaglate (Hexabrix) for efficacy and safety in 203 patients undergoing cardiac angiography, neurovascular angiography, peripheral and visceral angiography and intravenous pyelography. In all patients, adverse symptoms and signs including heat sense, pain, nausea, vomiting, etc. were checked during and after the injection. In addition, EKG and LV pressure were monitored during the cardiac angiography. And also CBC, UA, BUN and creatinine were checked before and 24 hours after the cardiac angiography. Serious adverse effect did not occur in any case. Minor effects, such as nausea and abdominal pain, were less frequently caused by non-ionic contrast media than by ionic contrast media, especially in cardiac angiography and intravenous pyelography. There was no significant difference between ionic and non-ionic contrast media in regard to electrophysiologic parameters such as EKG and LV pressure. In case of intravenous pyelography, nonionic contrast media seemed to be superior to ionic contrast media in image quality. It is suggested that, in spite of higher cost, non-ionic contrast media be needed for the safety and image quality, particularly in those patients at high risk of adverse effects by ionic contrast media

Density functional theory study on the ionic liquid pyridinium hydrogen sulfate

Science.gov (United States)

Tankov, Ivaylo; Yankova, Rumyana; Genieva, Svetlana; Mitkova, Magdalena; Stratiev, Dicho

2017-07-01

The geometry, electronic structure and chemical reactivity of a pyridinium-based ionic liquid, pyridinium hydrogen sulfate ([H-Pyr]+[HSO4]-), have been discussed on the basis of quantum chemical density functional theory calculations using B3LYP/6-311+G(d,p) and B3LYP/6-311++G(2d,2p) approaches. The calculations indicated that [H-Pyr]+[HSO4]- exists in the form of an ion pair. A large electropositive potential was found on the pyridinium ring, while the regions of a negative electrostatic potential is linked with the lone pair of electronegative oxygen atoms in hydrogen sulfate anion ([HSO4]-). Electron transfer both within the anion, and between the anion and cation of an ion pair were described using natural bond orbital theory. The energy values of -7.1375 and -2.8801 eV were related to HOMO and LUMO orbitals, respectively.

Poly(Ionic Liquid: A New Phase in a Thermoregulated Phase Separated Catalysis and Catalyst Recycling System of Transition Metal-Mediated ATRP

Directory of Open Access Journals (Sweden)

Lan Yao

2018-03-01

Full Text Available Poly(ionic liquids (PILs have become the frontier domains in separation science because of the special properties of ionic liquids as well as their corresponding polymers. Considering their function in separation, we designed and synthesized a thermoregulated PIL. That is, this kind of PIL could separate with an organic phase which dissolves the monomers at ambient temperature. When heated to the reaction temperature, they become a homogeneous phase, and they separate again when the temperature falls to the ambient temperature after polymerization. Based on this, a thermoregulated phase separated catalysis (TPSC system for Cu-based atom transfer radical polymerization (ATRP was constructed. The copper catalyst (CuBr2 used here is easily separated and recycled in situ just by changing the temperature in this system. Moreover, even when the catalyst had been recycled five times, the controllability over resultant polymers is still satisfying. Finally, only 1~2 ppm metal catalyst was left in the polymer solution phase, which indicates the really high recycling efficiency.

Thermotropic Ionic Liquid Crystals

Science.gov (United States)

Axenov, Kirill V.; Laschat, Sabine

2011-01-01

The last five years’ achievements in the synthesis and investigation of thermotropic ionic liquid crystals are reviewed. The present review describes the mesomorphic properties displayed by organic, as well as metal-containing ionic mesogens. In addition, a short overview on the ionic polymer and self-assembled liquid crystals is given. Potential and actual applications of ionic mesogens are also discussed. PMID:28879986

Thermotropic Ionic Liquid Crystals

Directory of Open Access Journals (Sweden)

Sabine Laschat

2011-01-01

Full Text Available The last five years’ achievements in the synthesis and investigation of thermotropic ionic liquid crystals are reviewed. The present review describes the mesomorphic properties displayed by organic, as well as metal-containing ionic mesogens. In addition, a short overview on the ionic polymer and self-assembled liquid crystals is given. Potential and actual applications of ionic mesogens are also discussed.

Thermotropic Ionic Liquid Crystals.

Science.gov (United States)

Axenov, Kirill V; Laschat, Sabine

2011-01-14

The last five years' achievements in the synthesis and investigation of thermotropic ionic liquid crystals are reviewed. The present review describes the mesomorphic properties displayed by organic, as well as metal-containing ionic mesogens. In addition, a short overview on the ionic polymer and self-assembled liquid crystals is given. Potential and actual applications of ionic mesogens are also discussed.

Thermotropic Ionic Liquid Crystals

OpenAIRE

Axenov, Kirill V.; Laschat, Sabine

2011-01-01

The last five years’ achievements in the synthesis and investigation of thermotropic ionic liquid crystals are reviewed. The present review describes the mesomorphic properties displayed by organic, as well as metal-containing ionic mesogens. In addition, a short overview on the ionic polymer and self-assembled liquid crystals is given. Potential and actual applications of ionic mesogens are also discussed.

Novel thiosalicylate-based ionic liquids for heavy metal extractions

Energy Technology Data Exchange (ETDEWEB)

Leyma, Raphlin; Platzer, Sonja [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna (Austria); Jirsa, Franz [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna (Austria); Department of Zoology, University of Johannesburg, PO Box 524, Auckland Park, 2006, Johannesburg (South Africa); Kandioller, Wolfgang, E-mail: wolfgang.kandioller@univie.ac.at [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna (Austria); Krachler, Regina; Keppler, Bernhard K. [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, A-1090 Vienna (Austria)

2016-08-15

Highlights: • Six thiosalicylate-based ammonium and phosphonium ionic liquids (ILs) were newly synthesized. • ILs showed good extraction of cadmium, copper, and zinc. • Phosphonium ILs showed better extraction efficiencies than their ammonium counterparts. - Abstract: This study aims to develop novel ammonium and phosphonium ionic liquids (ILs) with thiosalicylate (TS) derivatives as anions and evaluate their extracting efficiencies towards heavy metals in aqueous solutions. Six ILs were synthesized, characterized, and investigated for their extracting efficacies for cadmium, copper, and zinc. Liquid-liquid extractions of Cu, Zn, or Cd with ILs after 1–24 h using model solutions (pH 7; 0.1 M CaCl{sub 2}) were assessed using flame atomic absorption spectroscopy (F-AAS). Phosphonium-based ILs trihexyltetradecylphosphonium 2-(propylthio)benzoate [P{sub 66614}][PTB] and 2-(benzylthio)benzoate [P{sub 66614}][BTB] showed best extraction efficiency for copper and cadmium, respectively and zinc was extracted to a high degree by [P{sub 66614}][BTB] exclusively.

Characterization of hafnium oxide resistive memory layers deposited on copper by atomic layer deposition

Energy Technology Data Exchange (ETDEWEB)

Briggs, B.D.; Bishop, S.M. [SUNY College of Nanoscale Science and Engineering, 255 Fuller Road, Albany, NY 12203 (United States); Leedy, K.D. [Air Force Research Laboratory, 2241 Avionics Circle, Wright Patterson Air Force Base, Dayton, OH 45433 (United States); Cady, N.C., E-mail: ncady@albany.edu [SUNY College of Nanoscale Science and Engineering, 255 Fuller Road, Albany, NY 12203 (United States)

2014-07-01

Hafnium oxide-based resistive memory devices have been fabricated on copper bottom electrodes. The HfO{sub x} active layers in these devices were deposited by atomic layer deposition (ALD) at 250 °C with tetrakis(dimethylamido)hafnium(IV) as the metal precursor and an O{sub 2} plasma as the reactant. Depth profiles of the HfO{sub x} by X-ray photoelectron spectroscopy and secondary ion mass spectroscopy revealed a copper concentration on the order of five atomic percent throughout the HfO{sub x} film. In addition to the Cu doped HfO{sub x}, a thin layer (20 nm) of Cu{sub x}O is present at the surface. This surface layer is believed to have formed during the ALD process, and greatly complicates the analysis of the switching mechanism. The resistive memory structures fabricated from the ALD HfO{sub x} exhibited non-polar resistive switching, independent of the top metal electrode (Ni, Pt, Al, Au). Resistive switching current voltage (I–V) curves were analyzed using Schottky emission and ionic hopping models to gain insight into the physical mechanisms underpinning the device behavior. During the forming process it was determined that, at voltages in excess of 2.5 V, an ionic hopping model is in good agreement with the I–V data. The extracted ion hopping distance ∼ 4 Å was within the range of interatomic spacing of HfO{sub 2} during the forming process consistent with ionic motion of Cu{sup 2+} ions. Lastly the on state I–V data was dominated at larger voltages by Schottky emission with an estimated barrier height of ∼ 0.5 eV and a refractive index of 2.59. The consequence of the Schottky emission analysis indicates the on state resistance to be a product of a Pt/Cu{sub 2}O/Cu filament(s)/Cu{sub 2}O/Cu structure. - Highlights: • HfO{sub 2} was grown via atomic layer deposition at 250 and 100 °C on Cu substrates. • A Cu{sub 2}O surface layer and Cu doping were observed in post-deposition of HfO{sub 2}. • Resistive memory devices were fabricated and

Excitation and charge transfer in low-energy hydrogen atom collisions with neutral iron

Science.gov (United States)

Barklem, P. S.

2018-05-01

Data for inelastic processes due to hydrogen atom collisions with iron are needed for accurate modelling of the iron spectrum in late-type stars. Excitation and charge transfer in low-energy Fe+H collisions is studied theoretically using a previously presented method based on an asymptotic two-electron linear combination of atomic orbitals model of ionic-covalent interactions in the neutral atom-hydrogen-atom system, together with the multi-channel Landau-Zener model. An extensive calculation including 166 covalent states and 25 ionic states is presented and rate coefficients are calculated for temperatures in the range 1000-20 000 K. The largest rates are found for charge transfer processes to and from two clusters of states around 6.3 and 6.6 eV excitation, corresponding in both cases to active 4d and 5p electrons undergoing transfer. Excitation and de-excitation processes among these two sets of states are also significant. Full Tables and rate coefficient data are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/612/A90

Reactions of substituted benzene anions with N and O atoms: Chemistry in Titan’s upper atmosphere and the interstellar medium

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhe-Chen; Bierbaum, Veronica M. [Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309 (United States)

2016-06-07

The likely existence of aromatic anions in many important extraterrestrial environments, from the atmosphere of Titan to the interstellar medium (ISM), is attracting increasing attention. Nitrogen and oxygen atoms are also widely observed in the ISM and in the ionospheres of planets and moons. In the current work, we extend previous studies to explore the reactivity of prototypical aromatic anions (deprotonated toluene, aniline, and phenol) with N and O atoms both experimentally and computationally. The benzyl and anilinide anions both exhibit slow associative electron detachment (AED) processes with N atom, and moderate reactivity with O atom in which AED dominates but ionic products are also formed. The reactivity of phenoxide is dramatically different; there is no measurable reaction with N atom, and the moderate reactivity with O atom produces almost exclusively ionic products. The reaction mechanisms are studied theoretically by employing density functional theory calculations, and spin conversion is found to be critical for understanding some product distributions. This work provides insight into the rich gas-phase chemistry of aromatic ion-atom reactions and their relevance to ionospheric and interstellar chemistry.

Extractive behavior of U(VI) in the paraffin soluble ionic liquid

International Nuclear Information System (INIS)

Rama, R.; Kumaresan, R.; Venkatesan, K.A.; Antony, M.P.; Vasudeva Rao, P.R.

2013-01-01

An Aliquat-336 based ionic liquid namely, tri-n-octylmethylammonium bis(2-ethylhexyl)phosphate ((A3636) + (DEHP) - ) was prepared and studied for the extraction of U(VI) from nitric acid medium. Since the ionic liquid, (A336) + (DEHP) - , was miscible in n-dodecane (n-DD), the extraction of U(VI) in the solution of tri-n-butylphosphate (TBP) in n-DD, was investigated in the presence of small concentrations of ionic liquid. The distribution ratio of U(VI) in 0.3 M (A336) + (DEHP) - /n-DD decreased with increase in the concentration of nitric acid. The effect of concentration of TBP, ionic liquid nitric acid and nitrate ion on the extraction of U(VI) in ionic liquid medium was studied. The mechanistic aspect of extraction was investigated by the slope analysis of the extraction data. The studies indicated the feasibility of modifying the extractive properties of U(VI) in TBP/n-DD using ionic liquid. (author)

Thermodynamics of ionic processes in solutions

International Nuclear Information System (INIS)

Krestov, G.A.

1984-01-01

The present nitions about the mechanism of solvation of atomic-molecular particles and the structure of electrolyte and non electrolyte solutions are given. From common positions a wide range of interrelated problems (general and thermodynamic characteristic of ions, thermodynamic characteristic of ion solvation and various ionic reactions in solutions, structural changes of the solvent in the above processes etc...) is considered. The latest scientific data including those on the effect on the thermodynamio properties of low temperatures, various impurities (air, water), large ions, peculiarities of the structure of solvent molecules reflected. Considerable attention is given to new conceptions definitions, structural notions as well as theoretical and experimental methods of obtaining quantitative characteristics of ion solvation

Learning Ionic

CERN Document Server

Ravulavaru, Arvind

2015-01-01

This book is intended for those who want to learn how to build hybrid mobile applications using Ionic. It is also ideal for people who want to explore theming for Ionic apps. Prior knowledge of AngularJS is essential to complete this book successfully.

Nanoscale Ionic Liquids

Science.gov (United States)

2006-11-01

Technical Report 11 December 2005 - 30 November 2006 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Nanoscale Ionic Liquids 5b. GRANT NUMBER FA9550-06-1-0012...Title: Nanoscale Ionic Liquids Principal Investigator: Emmanuel P. Giannelis Address: Materials Science and Engineering, Bard Hall, Cornell University...based fluids exhibit high ionic conductivity. The NFs are typically synthesized by grafting a charged, oligomeric corona onto the nanoparticle cores

3+ and [Sb13Se16Br2] 5+ - Double and quadruple spiro cubanes from ionic liquids

KAUST Repository

Ahmed, Ejaz

2014-01-08

The reaction of antimony and selenium in the bromine-rich Lewis acidic ionic liquid [BMIm]Br·4.7AlBr3 (BMIm: 1-butyl-3- methylimidazolium) in the presence of a small amount of NbCl5 at 160 °C yielded dark-red crystals of [Sb7Se8Br 2][AlX4]3. For X = Cl0.15(1)Br 0.85(1), the compound is isostructural to [Sb7S 8Br2][AlCl4]3 [P212 121, a = 12.5132(5) Å, b = 17.7394(6) Å, c = 18.3013(6) Å]. For a higher chlorine content, X = Cl 0.58(1)Br0.42(1), a slightly disordered variant with a bisected unit cell is found [P21212, a = 12.3757(3) Å, b = 17.4116(5) Å, c = 9.0420(2) Å]. The [Sb 7Se8Br2]3+ heteropolycation (C 2 symmetry) is a spiro double-cubane with an antimony atom on the shared corner. From this distorted octahedrally coordinated central atom, tricoordinate selenium and antimony atoms alternate in the bonding sequence. The terminal antimony atoms each bind to a bromine atom. Quantum chemical calculations confirm polar covalent Sb-Se bonding within the cubes and indicate three-center, four-electron bonds for the six-coordinate spiro atoms. The calculated charge distribution reflects the electron-donor role of the antimony atoms. The use of a chlorine-rich ionic liquid resulted in the formation of triclinic [Sb13Se16Br2][AlX4] 5 with X = Cl0.80(1)Br0.20(1) [P$\\\\bar {1}$, a = 9.0842(5) Å, b = 19.607(1) Å, c = 21.511(1) Å, α = 64.116(6), β = 79.768(7), γ = 88.499(7)]. The cationic cluster [Sb13Se16Br2]5+ is a bromine-terminated spiro quadruple-cubane. This 31 atom concatenation of four cubes is assumed to be the largest known discrete main group polycation. A similar reaction in a chloride-free system yielded [Sb7Se 8Br2][Sb13Se16Br2] [AlBr4]8. In its monoclinic structure [P2/c, a = 27.214(5) Å, b = 9.383(2) Å, c = 22.917(4) Å, β = 101.68(1)], the two types of polycations alternate in layers along the a axis. In the series [Sb4+3nSe4+4nBr2](2+n)+, these cations are the members with n = 1 and 3. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGa

Formation of Rydberg states in fast ion-atom collisions

International Nuclear Information System (INIS)

Schneider, D.; Kanter, E.P.; Vager, Z.; Gemmell, D.; Koch, P.; Mariani, D.; Van de Water, W.

1983-01-01

Previous results from beam-foil spectroscopy and from experiments using field ionization techniques have shown that a significant fraction of fast ionic projectiles traversing solid targets can be excited to high Rydberg states. We report an experimental investigation of Rydberg states formed in atomic and molecular ion beams (MeV) emerging from thin-carbon foils. Different field arrangements, including μ-wave fields, have been applied to study the effects of field ionization. The yields of electrons produced via field ionization are compared for different projectile atoms and molecules

Mixed system of ionic liquid and non-ionic surfactants in aqueous media: Surface and thermodynamic properties

International Nuclear Information System (INIS)

Bhatt, Darshak; Maheria, Kalpana; Parikh, Jigisha

2014-01-01

Highlights: • Interaction of ionic liquid and ethylene oxide based non-ionic surfactants in aqueous media. • Evaluation of various surface properties and thermodynamic parameters. • Micellar growth ensues from exothermic to endothermic with increase in temperature. • Micelle formation is enthalpy driven at low temperature and entropy driven at higher temperature. • The micellization power and adsorption proficiency decreased at high IL concentrations. - Abstract: The mixed system of ionic liquid (IL) tetraethyl ammonium tetrafluoroborate [TEA(BF 4 )] and numerous ethylene oxide based non-ionic surfactants in aqueous media were studied using surface tension, viscosity and dynamic light scattering (DLS) measurements. Various surface properties like critical micelle concentration (cmc), maximum surface excess concentration (Γ max ), minimum surface area per surfactant molecule (A min ), surface tension at the cmc (γ cmc ), adsorption efficiency (pC 20 ), and effectiveness of surface tension reduction (π cmc ) as well as thermodynamic parameters of micellization have been determined. DLS and viscosity measurements revealed that the micellar growth was attributed to the bridged solvophilicity of the POE chain in surfactants at elevated temperatures. In most of the cases, the progression ensues from exothermic to endothermic with increase in temperature of the mixed system. Thermodynamic parameter indicates that the micelle formation process is enthalpy driven at low temperature and entropy driven at higher temperature

Laser-induced microscopic phase-transition on an ionic liquid

International Nuclear Information System (INIS)

Iguchi, Natsuki; Datta, Alokmay; Yoshikawa, Kenichi; Ma Yue

2009-01-01

Nematic-isotropic transition is induced in a 5 μm 'droplet' within an oriented bulk of a mixture of a liquid crystalline material with a room-temperature ionic liquid, by a laser working at 532 nm with an output power of 200 mW and a beam diameter of 1 μm. No microscopic phase transition is observed either in absence of the ionic liquid or at the other wavelength of 1064 nm, available to the Nd-YAG laser. This indicates the essential role on a resonant transfer of energy to the ionic liquid from the laser radiation, which is subsequently transferred to the liquid crystal. Spectroscopy of the pure liquid crystal and ionic liquid samples confirms this concept. Spatio-temporal image of the droplet growth shows, however, that the phase transition remains confined within the microscopic domain for the first 50 s, and then spreads out rapidly. Since resonant, quantum transitions between molecular levels takes place in less than microseconds, the about seven orders of magnitude slowing down of energy transfer observed here suggests unique hierarchical dynamics including the coupling between the intra-molecular motions in the ionic liquid and the inter-molecular forces between ionic liquid and liquid crystal.

Nanomechanics of layer-by-layer polyelectrolyte complexes: a manifestation of ionic cross-links and fixed charges.

Science.gov (United States)

Han, Biao; Chery, Daphney R; Yin, Jie; Lu, X Lucas; Lee, Daeyeon; Han, Lin

2016-01-28

This study investigates the roles of two distinct features of ionically cross-linked polyelectrolyte networks - ionic cross-links and fixed charges - in determining their nanomechanical properties. The layer-by-layer assembled poly(allylamine hydrochloride)/poly(acrylic acid) (PAH/PAA) network is used as the model material. The densities of ionic cross-links and fixed charges are modulated through solution pH and ionic strength (IS), and the swelling ratio, elastic and viscoelastic properties are quantified via an array of atomic force microscopy (AFM)-based nanomechanical tools. The roles of ionic cross-links are underscored by the distinctive elastic and viscoelastic nanomechanical characters observed here. First, as ionic cross-links are highly sensitive to solution conditions, the instantaneous modulus, E0, exhibits orders-of-magnitude changes upon pH- and IS-governed swelling, distinctive from the rubber elasticity prediction based on permanent covalent cross-links. Second, ionic cross-links can break and self-re-form, and this mechanism dominates force relaxation of PAH/PAA under a constant indentation depth. In most states, the degree of relaxation is >90%, independent of ionic cross-link density. The importance of fixed charges is highlighted by the unexpectedly more elastic nature of the network despite low ionic cross-link density at pH 2.0, IS 0.01 M. Here, the complex is a net charged, loosely cross-linked, where the degree of relaxation is attenuated to ≈50% due to increased elastic contribution arising from fixed charge-induced Donnan osmotic pressure. In addition, this study develops a new method for quantifying the thickness of highly swollen polymer hydrogel films. It also underscores important technical considerations when performing nanomechanical tests on highly rate-dependent polymer hydrogel networks. These results provide new insights into the nanomechanical characters of ionic polyelectrolyte complexes, and lay the ground for further

First-principles study of the alkali earth metal atoms adsorption on graphene

International Nuclear Information System (INIS)

Sun, Minglei; Tang, Wencheng; Ren, Qingqiang; Wang, Sake; JinYu; Du, Yanhui; Zhang, Yajun

2015-01-01

Graphical abstract: - Highlights: • The adsorption of Be and Mg adatoms on graphene is physisorption. • Ca, Sr, and Ba adatoms bond ionically to graphene and the most stable adsorption site for them is hollow site. • The zero band gap semiconductor graphene becomes metallic and magnetic after the adsorption of Ca, Sr, and Ba adatoms. - Abstract: Geometries, electronic structures, and magnetic properties for alkali earth metal atoms absorbed graphene have been studied by first-principle calculations. For Be and Mg atoms, the interactions between the adatom and graphene are weak van der Waals interactions. In comparison, Ca, Sr and Ba atoms adsorption on graphene exhibits strong ionic bonding with graphene. We found that these atoms bond to graphene at the hollow site with a significant binding energy and large electron transfer. It is intriguing that these adatoms may induce important changes in both the electronic and magnetic properties of graphene. Semimetal graphene becomes metallic and magnetic due to n-type doping. Detailed analysis shows that the s orbitals of these adatoms should be responsible for the arising of the magnetic moment. We believe that our results are suitable for experimental exploration and useful for graphene-based nanoelectronic and data storage.

First-principles study of the alkali earth metal atoms adsorption on graphene

Energy Technology Data Exchange (ETDEWEB)

Sun, Minglei [School of Mechanical Engineering, Southeast University, Nanjing 211189, Jiangsu (China); Tang, Wencheng, E-mail: 101000185@seu.edu.cn [School of Mechanical Engineering, Southeast University, Nanjing 211189, Jiangsu (China); Ren, Qingqiang [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, Hunan (China); Wang, Sake [Department of Physics, Southeast University, Nanjing 210096, Jiangsu (China); JinYu [School of Materials Science and Engineering, Southeast University, Nanjing 211189, Jiangsu (China); Jiangsu Key Laboratory of Advanced Metallic Materials, Southeast University, Nanjing 211189, Jiangsu (China); Du, Yanhui [School of Mechanical Engineering, Southeast University, Nanjing 211189, Jiangsu (China); Zhang, Yajun [Department of Engineering Mechanics, School of Aeronautics and Astronautics, Zhejiang University, Hangzhou 310027, Zhejiang (China)

2015-11-30

Graphical abstract: - Highlights: • The adsorption of Be and Mg adatoms on graphene is physisorption. • Ca, Sr, and Ba adatoms bond ionically to graphene and the most stable adsorption site for them is hollow site. • The zero band gap semiconductor graphene becomes metallic and magnetic after the adsorption of Ca, Sr, and Ba adatoms. - Abstract: Geometries, electronic structures, and magnetic properties for alkali earth metal atoms absorbed graphene have been studied by first-principle calculations. For Be and Mg atoms, the interactions between the adatom and graphene are weak van der Waals interactions. In comparison, Ca, Sr and Ba atoms adsorption on graphene exhibits strong ionic bonding with graphene. We found that these atoms bond to graphene at the hollow site with a significant binding energy and large electron transfer. It is intriguing that these adatoms may induce important changes in both the electronic and magnetic properties of graphene. Semimetal graphene becomes metallic and magnetic due to n-type doping. Detailed analysis shows that the s orbitals of these adatoms should be responsible for the arising of the magnetic moment. We believe that our results are suitable for experimental exploration and useful for graphene-based nanoelectronic and data storage.

Lifetime measurement of excited atomic and ionic states of some

Indian Academy of Sciences (India)

High-frequency deflection (HFD) technique with a delayed coincidence single photon counting arrangement is an efficient technique for radiative lifetime measurement. An apparatus for measurement of the radiative lifetime of atoms and molecules has been developed in our laboratory and measurements have been ...

Ionic conduction in polyether-based lithium arylfluorosulfonimide ionic melt electrolytes

International Nuclear Information System (INIS)

Herath, Mahesha B.; Creager, Stephen E.; Rajagopal, Rama V.; Geiculescu, Olt E.; DesMarteau, Darryl D.

2009-01-01

We report synthesis, characterization and ion transport in polyether-based ionic melt electrolytes consisting of Li salts of low-basicity anions covalently attached to polyether oligomers. Purity of the materials was investigated by HPLC analysis and electrospray ionization mass spectrometry. The highest ionic conductivity of 7.1 x 10 -6 S/cm at 30 deg. C was obtained for the sample consisting of a lithium salt of an arylfluorosulfonimide anion attached to a polyether oligomer with an ethyleneoxide (EO) to lithium ratio of 12. The conductivity order of various ionic melts having different polyether chain lengths suggests that at higher EO:Li ratios the conductivity of the electrolytes at room temperature is determined in part by the amount of crystallization of the polyether portion of the ionic melt.

Toxicity prediction of ionic liquids based on Daphnia magna by using density functional theory

Science.gov (United States)

Nu’aim, M. N.; Bustam, M. A.

2018-04-01

By using a model called density functional theory, the toxicity of ionic liquids can be predicted and forecast. It is a theory that allowing the researcher to have a substantial tool for computation of the quantum state of atoms, molecules and solids, and molecular dynamics which also known as computer simulation method. It can be done by using structural feature based quantum chemical reactivity descriptor. The identification of ionic liquids and its Log[EC50] data are from literature data that available in Ismail Hossain thesis entitled “Synthesis, Characterization and Quantitative Structure Toxicity Relationship of Imidazolium, Pyridinium and Ammonium Based Ionic Liquids”. Each cation and anion of the ionic liquids were optimized and calculated. The geometry optimization and calculation from the software, produce the value of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). From the value of HOMO and LUMO, the value for other toxicity descriptors were obtained according to their formulas. The toxicity descriptor that involves are electrophilicity index, HOMO, LUMO, energy gap, chemical potential, hardness and electronegativity. The interrelation between the descriptors are being determined by using a multiple linear regression (MLR). From this MLR, all descriptors being analyzed and the descriptors that are significant were chosen. In order to develop the finest model equation for toxicity prediction of ionic liquids, the selected descriptors that are significant were used. The validation of model equation was performed with the Log[EC50] data from the literature and the final model equation was developed. A bigger range of ionic liquids which nearly 108 of ionic liquids can be predicted from this model equation.

Ionic liquids in chemical engineering.

Science.gov (United States)

Werner, Sebastian; Haumann, Marco; Wasserscheid, Peter

2010-01-01

The development of engineering applications with ionic liquids stretches back to the mid-1990s when the first examples of continuous catalytic processes using ionic liquids and the first studies of ionic liquid-based extractions were published. Ever since, the use of ionic liquids has seen tremendous progress in many fields of chemistry and engineering, and the first commercial applications have been reported. The main driver for ionic liquid engineering applications is to make practical use of their unique property profiles, which are the result of a complex interplay of coulombic, hydrogen bonding and van der Waals interactions. Remarkably, many ionic liquid properties can be tuned in a wide range by structural modifications at their cation and anion. This review highlights specific examples of ionic liquid applications in catalysis and in separation technologies. Additionally, the application of ionic liquids as working fluids in process machines is introduced.

Thermionic detection of the ionic fragments of continiuum-state pair absorption systems

International Nuclear Information System (INIS)

Hotop, R.; Niemax, K.; Richter, J.; Weber, K.H.

1981-01-01

Using a thermionic diode we have detected the ionic fragments formed by associative ionization and dissociation after continuum-state pair absorption processes in Cs-Cs and Cs-K systems. Assuming an ionization probability of unity of the excited species and calibrating the pair absorption bands by taking into account the known photoionization cross section of the atoms we found excellent agreement with data from classical absorption measurements. (orig.)

Atomic Charges and Chemical Bonding in Y-Ga Compounds

Directory of Open Access Journals (Sweden)

Yuri Grin

2018-02-01

Full Text Available A negative deviation from Vegard rule for the average atomic volume versus yttrium content was found from experimental crystallographic information about the binary compounds of yttrium with gallium. Analysis of the electron density (DFT calculations employing the quantum theory of atoms in molecules revealed an increase in the atomic volumes of both Y and Ga with the increase in yttrium content. The non-linear increase is caused by the strengthening of covalent Y-Ga interactions with stronger participation of genuine penultimate shell electrons (4d electrons of yttrium in the valence region. Summing the calculated individual atomic volumes for a unit cell allows understanding of the experimental trend. With increasing yttrium content, the polarity of the Y-Ga bonding and, thus its ionicity, rises. The covalency of the atomic interactions in Y-Ga compounds is consistent with their delocalization from two-center to multi-center ones.

Green Imidazolium Ionics-From Truly Sustainable Reagents to Highly Functional Ionic Liquids.

Science.gov (United States)

Tröger-Müller, Steffen; Brandt, Jessica; Antonietti, Markus; Liedel, Clemens

2017-09-04

We report the synthesis of task-specific imidazolium ionic compounds and ionic liquids with key functionalities of organic molecules from electro-, polymer-, and coordination chemistry. Such products are highly functional and potentially suitable for technology applications even though they are formed without elaborate reactions and from cheap and potentially green reagents. We further demonstrate the versatility of the used synthetic approach by introducing different functional and green counterions to the formed ionic liquids directly during the synthesis or after metathesis reactions. The influence of different cation structures and different anions on the thermal and electrochemical properties of the resulting ionic liquids is discussed. Our goal is to make progress towards economically competitive and sustainable task-specific ionic liquids. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of a new green non-dispersive ionic liquid microextraction method in a narrow glass column for determination of cadmium prior to couple with graphite furnace atomic absorption spectrometry

Energy Technology Data Exchange (ETDEWEB)

Naeemullah, E-mail: naeemullah433@yahoo.com [Gaziosmanpaşa University, Faculty of Science and Arts, Chemistry Department, 60250 Tokat (Turkey); National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Kazi, Tasneem Gul [National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Tuzen, Mustafa [Gaziosmanpaşa University, Faculty of Science and Arts, Chemistry Department, 60250 Tokat (Turkey); Shah, Faheem; Afridi, Hassan Imran [National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Citak, Demirhan [Gaziosmanpaşa University, Faculty of Science and Arts, Chemistry Department, 60250 Tokat (Turkey)

2014-02-17

Graphical abstract: -- Highlights: •A novel and rapid non-dispersive ionic liquid based microextractions. •We used a long narrow glass column to provide more contact area between two media (aqueous and extractive). •APDC using as complexing agent and analyzed by GFAAS. •Introduced a novel approach that reduced solvent consumption, effort, time. •It was applied for determination of understudy analytes in real water sample. -- Abstract: Easy and innovative non-dispersive ionic liquid based microextraction (NDILME) has been developed for preconcentration of trace level of cadmium (Cd) in aqueous real surface water samples prior to couple with graphite furnace atomic absorption spectrometry (GFAAS). A 200 cm long narrow glass column containing aqueous solution of standard/sample was used to increase phase transfer ratio by providing more contact area between two medium (aqueous and extractive), which drastically improve the recoveries of labile hydrophobic chelate of Cd ammonium pyrrolidinedithiocarbamate (APDC), into ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate [C{sub 4}mim][PF{sub 6}]. Different aspect of the desire method have been investigated and optimized. Under the optimized key experimental variables, limit of detection (LOD) and enhancement factor (EF) were achieved to be 0.5 ng L{sup −1} and 150, respectively. Reliability of the model method was checked by relative standard deviation (%RSD), which was found to be < 5%. Validity and accuracy of the developed method was checked by analysis of certified reference water samples (SLRS-4 Riverine water) using standard addition method. Application of the model method was productively performed by analysis of Cd in real surface water samples (tap and sea)

Low Temperature Reduction of Alumina Using Fluorine Containing Ionic Liquids

Energy Technology Data Exchange (ETDEWEB)

Dr. R. G. Reddy

2007-09-01

The major objective of the project is to establish the feasibility of using specific ionic liquids capable of sustaining aluminum electrolysis near room temperature at laboratory and batch recirculation scales. It will explore new technologies for aluminum and other valuable metal extraction and process methods. The new technology will overcome many of the limitations associated with high temperatures processes such as high energy consumption and corrosion attack. Furthermore, ionic liquids are non-toxic and could be recycled after purification, thus minimizing extraction reagent losses and environmental pollutant emissions. Ionic liquids are mixture of inorganic and organic salts which are liquid at room temperature and have wide operational temperature range. During the last several years, they were emerging as novel electrolytes for extracting and refining of aluminum metals and/or alloys, which are otherwise impossible using aqueous media. The superior high temperature characteristics and high solvating capabilities of ionic liquids provide a unique solution to high temperature organic solvent problems associated with device internal pressure build-up, corrosion, and thermal stability. However their applications have not yet been fully implemented due to the insufficient understanding of the electrochemical mechanisms involved in processing of aluminum with ionic liquids. Laboratory aluminum electrodeposition in ionic liquids has been investigated in chloride and bis (trifluoromethylsulfonyl) imide based ionic liquids. The electrowinning process yielded current density in the range of 200-500 A/m2, and current efficiency of about 90%. The results indicated that high purity aluminum (>99.99%) can be obtained as cathodic deposits. Cyclic voltammetry and chronoamperometry studies have shown that initial stages of aluminum electrodeposition in ionic liquid electrolyte at 30°C was found to be quasi-reversible, with the charge transfer coefficient (0.40). Nucleation

Thermophysical properties of ammonium and hydroxylammonium protic ionic liquids

International Nuclear Information System (INIS)

Chhotaray, Pratap K.; Gardas, Ramesh L.

2014-01-01

Highlights: • Density, viscosity and sound velocity measured for five ammonium and hydroxylammonium based protic ionic liquids. • Experimental density and viscosity data estimated using Gardas and Coutinho model and Vogel–Tamman–Fulcher equation. • Effects of cation, anion and alkyl chain length on studied properties have been discussed. • The intermolecular interactions were analyzed on the basis of derived properties. - Abstract: In this work, five protic ionic liquids having propylammonium, 3-hydroxy propylammonium as cations and formate, acetate, trifluoroacetate as anions have been synthesized. Thermophysical properties such as density (ρ), viscosity (η) and sound velocity (u) have been measured at various temperatures ranging from (293.15 to 343.15) K at atmospheric pressure. The experimental density and viscosity were fitted with second order polynomial and Vogel–Tamman–Fulcher (VTF) equations, respectively. Also experimental densities were correlated with the estimated density proposed by Gardas and Coutinho model. The coefficient of thermal expansion (α) and isentropic compressibility (β s ) values have been calculated from the experimental density and sound velocity data using empirical correlations. Lattice potential energy (U POT ) has been calculated to understand the strength of ionic interaction between the ions. Thermal decomposition temperature (T d ) and glass transition temperature (T g ) along with crystallization and melting point were investigated using TGA and DSC analysis, respectively. The effect of alkyl chain length and electronegative fluorine atoms on anionic fragment as well as hydroxyl substituent on cationic side chain in the protic ionic liquids has been discussed for studied properties. The effect of ΔpK a over the studied properties has also been analyzed

Comparing two tetraalkylammonium ionic liquids. I. Liquid phase structure

Energy Technology Data Exchange (ETDEWEB)

Lima, Thamires A.; Paschoal, Vitor H.; Faria, Luiz F. O.; Ribeiro, Mauro C. C., E-mail: mccribei@iq.usp.br [Laboratório de Espectroscopia Molecular, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, CP 26077, CEP 05513-970 São Paulo, SP (Brazil); Giles, Carlos [Departamento de Física da Matéria Condensada, Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, 13083-859 Campinas, SP (Brazil)

2016-06-14

X-ray scattering experiments at room temperature were performed for the ionic liquids n-butyl-trimethylammonium bis(trifluoromethanesulfonyl)imide, [N{sub 1114}][NTf{sub 2}], and methyl-tributylammonium bis(trifluoromethanesulfonyl)imide, [N{sub 1444}][NTf{sub 2}]. The peak in the diffraction data characteristic of charge ordering in [N{sub 1444}][NTf{sub 2}] is shifted to longer distances in comparison to [N{sub 1114}][NTf{sub 2}], but the peak characteristic of short-range correlations is shifted in [N{sub 1444}][NTf{sub 2}] to shorter distances. Molecular dynamics (MD) simulations were performed for these ionic liquids using force fields available from the literature, although with new sets of partial charges for [N{sub 1114}]{sup +} and [N{sub 1444}]{sup +} proposed in this work. The shifting of charge and adjacency peaks to opposite directions in these ionic liquids was found in the static structure factor, S(k), calculated by MD simulations. Despite differences in cation sizes, the MD simulations unravel that anions are allowed as close to [N{sub 1444}]{sup +} as to [N{sub 1114}]{sup +} because anions are located in between the angle formed by the butyl chains. The more asymmetric molecular structure of the [N{sub 1114}]{sup +} cation implies differences in partial structure factors calculated for atoms belonging to polar or non-polar parts of [N{sub 1114}][NTf{sub 2}], whereas polar and non-polar structure factors are essentially the same in [N{sub 1444}][NTf{sub 2}]. Results of this work shed light on controversies in the literature on the liquid structure of tetraalkylammonium based ionic liquids.

Ionic conductivity of ternary electrolyte containing sodium salt and ionic liquid

International Nuclear Information System (INIS)

Egashira, Minato; Asai, Takahito; Yoshimoto, Nobuko; Morita, Masayuki

2011-01-01

Highlights: ► Ternary electrolyte containing NaBF 4 , polyether and ionic liquid has been prepared. ► The conductivity of the electrolytes has been evaluated toward content of ionic liquid. ► The conductivity shows maximum 1.2 mS cm −1 and is varied in relation to solution structure. - Abstract: For the development of novel non-aqueous sodium ion conductor with safety of sodium secondary cell, non-flammable ionic liquid is attractive as electrolyte component. A preliminary study has been carried out for the purpose of constructing sodium ion conducting electrolyte based on ionic liquid. The solubility of sodium salt such as NaBF 4 in ionic liquid is poor, thus the ternary electrolyte has been prepared where NaBF 4 with poly(ethylene glycol) dimethyl ether (PEGDME) as coordination former is dissolved with ionic liquid diethyl methoxyethyl ammonium tetrafluoroborate (DEMEBF 4 ). The maximum conductivity among the prepared solutions, ca. 1.2 mS cm −1 at 25 °C, was obtained when the molar ratio (ethylene oxide unit in PEGDME):NaBF 4 :DEMEBF 4 was 8:1:2. The relationship between the conductivity of the ternary electrolyte and its solution structure has been discussed.

Electrochemical Model for Ionic Liquid Electrolytes in Lithium Batteries

International Nuclear Information System (INIS)

Yoo, Kisoo; Deshpande, Anirudh; Banerjee, Soumik; Dutta, Prashanta

2015-01-01

ABSTRACT: Room temperature ionic liquids are considered as potential electrolytes for high performance and safe lithium batteries due to their very low vapor pressure and relatively wide electrochemical and thermal stability windows. Unlike organic electrolytes, ionic liquid electrolytes are molten salts at room temperature with dissociated cations and anions. These dissociated ions interfere with the transport of lithium ions in lithium battery. In this study, a mathematical model is developed for transport of ionic components to study the performance of ionic liquid based lithium batteries. The mathematical model is based on a univalent ternary electrolyte frequently encountered in ionic liquid electrolytes of lithium batteries. Owing to the very high concentration of components in ionic liquid, the transport of lithium ions is described by the mutual diffusion phenomena using Maxwell-Stefan diffusivities, which are obtained from atomistic simulation. The model is employed to study a lithium-ion battery where the electrolyte comprises ionic liquid with mppy + (N-methyl-N-propyl pyrrolidinium) cation and TFSI − (bis trifluoromethanesulfonyl imide) anion. For a moderate value of reaction rate constant, the electric performance results predicted by the model are in good agreement with experimental data. We also studied the effect of porosity and thickness of separator on the performance of lithium-ion battery using this model. Numerical results indicate that low rate of lithium ion transport causes lithium depleted zone in the porous cathode regions as the porosity decreases or the length of the separator increases. The lithium depleted region is responsible for lower specific capacity in lithium-ion cells. The model presented in this study can be used for design of optimal ionic liquid electrolytes for lithium-ion and lithium-air batteries

Force microscopy of layering and friction in an ionic liquid

International Nuclear Information System (INIS)

Hoth, Judith; Hausen, Florian; Bennewitz, Roland; Müser, Martin H

2014-01-01

The mechanical properties of the ionic liquid 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl) trifluorophosphate ([Py 1,4 ][FAP]) in confinement between a SiO x and a Au(1 1 1) surface are investigated by means of atomic force microscopy (AFM) under electrochemical control. Up to 12 layers of ion pairs can be detected through force measurements while approaching the tip of the AFM to the surface. The particular shape of the force versus distance curve is explained by a model for the interaction between tip, gold surface and ionic liquid, which assumes an exponentially decaying oscillatory force originating from bulk liquid density correlations. Jumps in the tip–sample distance upon approach correspond to jumps of the compliant force sensor between branches of the oscillatory force curve. Frictional force between the laterally moving tip and the surface is detected only after partial penetration of the last double layer between tip and surface. (paper)

In situ direct observation of photocorrosion in ZnO crystals in ionic liquid using a laser-equipped high-voltage electron microscope

Directory of Open Access Journals (Sweden)

J. Ishioka

2017-03-01

Full Text Available ZnO photocatalysts in water react with environmental water molecules and corrode under illumination. ZnO nanorods in water can also grow because of water splitting induced by UV irradiation. To investigate their morphological behavior caused by crystal growth and corrosion, here we developed a new laser-equipped high-voltage electron microscope and observed crystal ZnO nanorods immersed in ionic liquid. Exposing the specimen holder to a laser with a wavelength of 325 nm, we observed the photocorrosion in situ at the atomic scale for the first time. This experiment revealed that Zn and O atoms near the interface between the ZnO nanorods and the ionic liquid tended to dissolve into the liquid. The polarity and facet of the nanorods were strongly related to photocorrosion and crystal growth.

Protic ammonium carboxylate ionic liquids: insight into structure, dynamics and thermophysical properties by alkyl group functionalization.

Science.gov (United States)

Reddy, Th Dhileep N; Mallik, Bhabani S

2017-04-19

This study is aimed at characterising the structure, dynamics and thermophysical properties of five alkylammonium carboxylate ionic liquids (ILs) from classical molecular dynamics simulations. The structural features of these ILs were characterised by calculating the site-site radial distribution functions, g(r), spatial distribution functions and structure factors. The structural properties demonstrate that ILs show greater interaction between cations and anions when alkyl chain length increases on the cation or anion. In all ILs, spatial distribution functions show that the anion is close to the acidic hydrogen atoms of the ammonium cation. We determined the role of alkyl group functionalization of the charged entities, cations and anions, in the dynamical behavior and the transport coefficients of this family of ionic liquids. The dynamics of ILs are described by studying the mean square displacement (MSD) of the centres of mass of the ions, diffusion coefficients, ionic conductivities and hydrogen bonds as well as residence dynamics. The diffusion coefficients and ionic conductivity decrease with an increase in the size of the cation or anion. The effect of alkyl chain length on ionic conductivity calculated in this article is consistent with the findings of other experimental studies. Hydrogen bond lifetimes and residence times along with structure factors were also calculated, and are related to alkyl chain length.

Synergetic enhancement effect of ionic liquid and diethyldithiocarbamate on the chemical vapor generation of nickel for its atomic fluorescence spectrometric determination in biological samples

International Nuclear Information System (INIS)

Zhang Chuan; Li Yan; Wu Peng; Yan Xiuping

2009-01-01

Room-temperature ionic liquid in combination with sodium diethyldithiocarbamate (DDTC) was used to synergetically improve the chemical vapor generation (CVG) of nickel. Volatile species of nickel were effectively generated through reduction of acidified analyte solution with KBH 4 in the presence of 0.02% DDTC and 25 mmol L -1 1-butyl-3-methylimidazolium bromide ([C 4 mim]Br) at room temperature. Thus, a new flow injection (FI)-CVG-atomic fluorescence spectrometric (FI-CVG-AFS) method was developed for determination of nickel with a detection limit of 0.65 μg L -1 (3 s) and a sampling frequency of 180 h -1 . With consumption of 0.5 mL sample solution, an enhancement factor of 2400 was obtained. The precision (RSD) for eleven replicate determinations of 20 μg L -1 Ni was 3.4%. The developed FI-CVG-AFS method was successfully applied to determination of trace Ni in several certified biological reference materials.

Generation, concentration and purification for ionic entangled states

International Nuclear Information System (INIS)

Yang Ming; Cao Zhuoliang

2007-01-01

In cavity QED, the atoms would be sent through the sequential arrays of cavities for the generation of multi-cavity entanglement, or several atoms would be sent into the same cavity mode one bye one for the generation of multi-atom entanglement. The complexity of these processes will impose limitations on the experimental feasibility of it. So, following our previous publication [International Journal Of Quantum Information 2, 231 (2004)] we will propose an alternative scheme for the preparation of multi-cavity W state via cavity QED, which uses the geometrical method to do what other authors have proposed previously using sequential arrays of cavities. Due to the impossibility that one quantum system can be isolated from the environment absolutely, the entanglement of the entangled objects will decrease exponentially with the propagating distance of the objects, and the practically available quantum entangled states are all non-maximally entangled states or the more general case--mixed states. Following our previous publications [Phys. Rev. A 72, 042307 (2005), ibid. 71, 012308 (2005)], we will propose an entanglement generation, concentration and purification scheme for atomic or ionic system, which is mainly based on Cavity QED and linear optical elements. This purification process avoids the controlled-NOT (C-NOT) operations needed in the original purification protocol, which simplifies the whole purification process

Real-Space Bonding Indicator Analysis of the Donor-Acceptor Complexes X3BNY3, X3AlNY3, X3BPY3, and X3AlPY3 (X, Y = H, Me, Cl).

Science.gov (United States)

Mebs, Stefan; Beckmann, Jens

2017-10-12

Calculations of real-space bonding indicators (RSBI) derived from Atoms-In-Molecules (AIM), Electron Localizability Indicator (ELI-D), Non-Covalent Interactions index (NCI), and Density Overlap Regions Indicator (DORI) toolkits for a set of 36 donor-acceptor complexes X 3 BNY 3 (1, 1a-1h), X 3 AlNY 3 (2, 2a-2h), X 3 BPY 3 (3, 3a-3h), and X 3 AlPY 3 (4, 4a-4h) reveal that the donor-acceptor bonds comprise covalent and ionic interactions in varying extents (X = Y = H for 1-4; X = H, Y = Me for 1a-4a; X = H, Y = Cl for 1b-4b; X = Me, Y = H for 1c-4c; X, Y = Me for 1d-4d; X = Me, Y = Cl for 1e-4e; X = Cl, Y = H for 1f-4f; X = Cl, Y = Me for 1g-4g; X, Y = Cl for 1h-4h). The phosphinoboranes X 3 BPY 3 (3, 3a-3h) in general and Cl 3 BPMe 3 (3f) in particular show the largest covalent contributions and the least ionic contributions. The aminoalanes X 3 AlNY 3 (2, 2a-2h) in general and Me 3 AlNCl 3 (2e) in particular show the least covalent contributions and the largest ionic contributions. The aminoboranes X 3 BNY 3 (1, 1a-1h) and the phosphinoalanes X 3 AlPY 3 (4, 4a-4h) are midway between phosphinoboranes and aminoalanes. The degree of covalency and ionicity correlates with the electronegativity difference BP (ΔEN = 0.15) < AlP (ΔEN = 0.58) < BN (ΔEN = 1.00) < AlN (ΔEN = 1.43) and a previously published energy decomposition analysis (EDA). To illustrate the importance of both contributions in Lewis formula representations, two resonance formulas should be given for all compounds, namely, the canonical form with formal charges denoting covalency and the arrow notation pointing from the donor to the acceptor atom to emphasis ionicity. If the Lewis formula mainly serves to show the atomic connectivity, the most significant should be shown. Thus, it is legitimate to present aminoalanes using arrows; however, for phosphinoboranes the canonical form with formal charges is more appropriate.

An active nano-supported interface designed from gold nanoparticles embedded on ionic liquid for depositing DNA

International Nuclear Information System (INIS)

Lu Liping; Kang Tianfang; Cheng Shuiyuan; Guo Xiurui

2009-01-01

The use of an active nano-interface designed from gold nanoparticles embedded on ionic liquid for DNA damage resulted from formalehyde (HCHO) is reported in this article. The active nano-interface was fabricated by depositing gold nanoparticles on the ionic liquid 1-butyl-3-methylimidazolium tetrafluroborate ([bmim][BF 4 ]). A glassy carbon electrode modified by this composite film was fabricated to immobilize DNA for probing into the damage resulted from HCHO. The modifying process was characterized by X-ray photoelectron spectroscopy, atomic force microscopy and electrochemistry involving electrochemical impedance spectroscopy. It was found that the modified film performs effectively in studying the DNA damage by electrocatalytic activity toward HCHO oxidation.

Oxidative desulfurization of dibenzothiophene from model oil using ionic liquids as extracting agent

Science.gov (United States)

Taha, Mohd F.; Atikah, N.; Chong, F. K.; Shaharun, Maizatul S.

2012-09-01

The oxidative desulfurization of dibenzothiophene (DBT) from model oil (in n-dodecane) was carried out using ionic liquid as the extractant and catalyst, and hydrogen peroxide (H2O2) in combination with acetic acid (CH3COOH) and sulphuric acid (H2SO4) as the oxidant. The ionic liquids used were 1-butyl-3-methylimidazolium octyl sulphate ([Bmim][OcSO4]) and 1-butyl-3-methylimidazolium acetate ([Bmim][Ac]). The effect of the amounts of H2O2 on oxidative desulphurization of model oil was first investigated without the usage of ionic liquids at room temperature. The results indicate that greater amount of H2O2 give higher desulfurization and the maximum desulfurization in this study, i.e. 34 %, was occurred when the molar ratio of H2O2 to sulfur was 5:1. With the usage of ionic liquid and the molar ratio of 5:1 (H2O2:sulfur), the efficiency of DBT removal from model oil was increased significantly in terms of percent removal and removal time. Ionic liquid of [Bmim][OcSO4] performed better than [Bmim][Ac] with 72 % DBT removal. When molar ratio of H2O2 to sulphur was 5:1, volume ratio of ionic liquid to model oil was 1:1 and mixing time was 60 min at room temperature. The results indicate the potential of ionic liquids as the extractant and catalyst for oxidative desulfurization of hydrocarbon fuels.

Theoretical and experimental studies on ionic currents in nanopore-based biosensors.

Science.gov (United States)

Liu, Lei; Li, Chu; Ma, Jian; Wu, Yingdong; Ni, Zhonghua; Chen, Yunfei

2014-12-01

Novel generation of analytical technology based on nanopores has provided possibilities to fabricate nanofluidic devices for low-cost DNA sequencing or rapid biosensing. In this paper, a simplified model was suggested to describe DNA molecule's translocation through a nanopore, and the internal potential, ion concentration, ionic flowing speed and ionic current in nanopores with different sizes were theoretically calculated and discussed on the basis of Poisson-Boltzmann equation, Navier-Stokes equation and Nernst-Planck equation by considering several important parameters, such as the applied voltage, the thickness and the electric potential distributions in nanopores. In this way, the basic ionic currents, the modulated ionic currents and the current drops induced by translocation were obtained, and the size effects of the nanopores were carefully compared and discussed based on the calculated results and experimental data, which indicated that nanopores with a size of 10 nm or so are more advantageous to achieve high quality ionic current signals in DNA sensing.

Task-specific thioglycolate ionic liquids for heavy metal extraction: Synthesis, extraction efficacies and recycling properties

Energy Technology Data Exchange (ETDEWEB)

Platzer, Sonja [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, 1090 Vienna (Austria); Kar, Mega [School of Chemistry, Monash University, Clayton, Victoria 3800 (Australia); Leyma, Raphlin; Chib, Sonia; Roller, Alexander [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, 1090 Vienna (Austria); Jirsa, Franz [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, 1090 Vienna (Austria); Department of Zoology, University of Johannesburg, PO Box 524, Auckland Park, 2006 Johannesburg (South Africa); Krachler, Regina [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, 1090 Vienna (Austria); MacFarlane, Douglas R. [School of Chemistry, Monash University, Clayton, Victoria 3800 (Australia); Kandioller, Wolfgang, E-mail: wolfgang.kandioller@univie.ac.at [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, 1090 Vienna (Austria); Keppler, Bernhard K. [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, 1090 Vienna (Austria)

2017-02-15

Highlights: • Thioglycolate-based ionic liquids have been synthesized and their physicochemical properties have been examined. • The developed ionic liquids can efficiently remove Cu(II) and Cd(II). • Loaded ionic liquids can be recycled by application of different stripping protocols. - Abstract: Eight novel task-specific ionic liquids (TSILs) based on the thioglycolate anion designed for heavy metal extraction have been prepared and characterized by {sup 1}H and {sup 13}C NMR, UV-Vis, infrared, ESI-MS, conductivity, viscosity, density and thermal properties. Evaluation of their time-resolved extraction abilities towards cadmium(II) and copper(II) in aqueous solutions have been investigated where distribution ratios up to 1200 were observed. For elucidation of the IL extraction mode, crystals were grown where Cd(II) was converted with an excess of S-butyl thioglycolate. It was found by X-ray diffraction analysis that cadmium is coordinated by five oxygen and one sulfur donor atoms provided by two thioglycolate molecules and one water molecule. Leaching behavior of the hydrophobic ionic liquids into aqueous systems was studied by TOC (total dissolved organic carbon) measurements. Additionally, the immobilization on polypropylene was elucidated and revealed slower metal extraction rates and similar leaching behavior. Finally, recovery processes for cadmium and copper after extraction were performed and recyclability was successfully proven for both metals.

The Nature of the Interactions in Triethanolammonium-Based Ionic Liquids. A Quantum Chemical Study.

Science.gov (United States)

Fedorova, Irina V; Safonova, Lyubov P

2018-05-10

Structural features and interionic interactions play a crucial role in determining the overall stability of ionic liquids and their physicochemical properties. Therefore, we performed high-level quantum-chemical study of different cation-anion pairs representing the building units of protic ionic liquids based on triethanolammonium cation and anions of sulfuric, nitric, phosphoric, and phosphorus acids to provide essential insight into these phenomena at the molecular level. It was shown that every structure is stabilized through multiple H bonds between the protons in the N-H and O-H groups of the cation and different oxygen atoms of the anion acid. Using atoms in molecules topological parameters and natural bond orbital analysis, we determined the nature and strength of these interactions. Our calculations suggest that the N-H group of the cation has more proton donor-like character than the O-H group that makes the N-H···O hydrogen bonds stronger. A close relation between the binding energies of these ion pairs and experimental melting points was established: the smaller the absolute value of the binding energy between ions, the lower is the melting point.

All solid-state polymer electrolytes prepared from a hyper-branched graft polymer using atom transfer radical polymerization

International Nuclear Information System (INIS)

Higa, Mitsuru; Fujino, Yukiko; Koumoto, Taihei; Kitani, Ryousuke; Egashira, Satsuki

2005-01-01

We propose an all solid-state (liquid free) polymer electrolyte (SPE) prepared from a hyper-branched graft copolymer. The graft copolymer consisting of a poly(methyl methacrylate) main chain and poly(ethylene glycol) methyl ether methacrylate side chains was synthesized by atom transfer radical polymerization changing the average chain distance between side chains, side chain length and branched chain length of the proposed structure of the graft copolymer. The ionic conductivity of the SPEs increases with increasing the side chain length, branched chain length and/or average distance between the side chains. The ionic conductivity of the SPE prepared from POEM 9 whose POEM content = 51 wt% shows 2 x 10 -5 S/cm at 30 deg. C. The tensile strength of the SPEs decreases with increases the side chain length, branched chain length and/or average distance between the side chains. These results indicate that a SPE prepared from the hyper-branched graft copolymer has potential to be applied to an all-solid polymer electrolyte

Vibrational Spectroscopy of Ionic Liquids.

Science.gov (United States)

Paschoal, Vitor H; Faria, Luiz F O; Ribeiro, Mauro C C

2017-05-24

Vibrational spectroscopy has continued use as a powerful tool to characterize ionic liquids since the literature on room temperature molten salts experienced the rapid increase in number of publications in the 1990's. In the past years, infrared (IR) and Raman spectroscopies have provided insights on ionic interactions and the resulting liquid structure in ionic liquids. A large body of information is now available concerning vibrational spectra of ionic liquids made of many different combinations of anions and cations, but reviews on this literature are scarce. This review is an attempt at filling this gap. Some basic care needed while recording IR or Raman spectra of ionic liquids is explained. We have reviewed the conceptual basis of theoretical frameworks which have been used to interpret vibrational spectra of ionic liquids, helping the reader to distinguish the scope of application of different methods of calculation. Vibrational frequencies observed in IR and Raman spectra of ionic liquids based on different anions and cations are discussed and eventual disagreements between different sources are critically reviewed. The aim is that the reader can use this information while assigning vibrational spectra of an ionic liquid containing another particular combination of anions and cations. Different applications of IR and Raman spectroscopies are given for both pure ionic liquids and solutions. Further issues addressed in this review are the intermolecular vibrations that are more directly probed by the low-frequency range of IR and Raman spectra and the applications of vibrational spectroscopy in studying phase transitions of ionic liquids.

Ionic liquids as electrolytes

International Nuclear Information System (INIS)

Galinski, Maciej; Lewandowski, Andrzej; Stepniak, Izabela

2006-01-01

Salts having a low melting point are liquid at room temperature, or even below, and form a new class of liquids usually called room temperature ionic liquids (RTIL). Information about RTILs can be found in the literature with such key words as: room temperature molten salt, low-temperature molten salt, ambient-temperature molten salt, liquid organic salt or simply ionic liquid. Their physicochemical properties are the same as high temperature ionic liquids, but the practical aspects of their maintenance or handling are different enough to merit a distinction. The class of ionic liquids, based on tetraalkylammonium cation and chloroaluminate anion, has been extensively studied since late 1970s of the XX century, following the works of Osteryoung. Systematic research on the application of chloroaluminate ionic liquids as solvents was performed in 1980s. However, ionic liquids based on aluminium halides are moisture sensitive. During the last decade an increasing number of new ionic liquids have been prepared and used as solvents. The general aim of this paper was to review the physical and chemical properties of RTILs from the point of view of their possible application as electrolytes in electrochemical processes and devices. The following points are discussed: melting and freezing, conductivity, viscosity, temperature dependence of conductivity, transport and transference numbers, electrochemical stability, possible application in aluminium electroplating, lithium batteries and in electrochemical capacitors

Hydrogen bonding in ionic liquids.

Science.gov (United States)

Hunt, Patricia A; Ashworth, Claire R; Matthews, Richard P

2015-03-07

Ionic liquids (IL) and hydrogen bonding (H-bonding) are two diverse fields for which there is a developing recognition of significant overlap. Doubly ionic H-bonds occur when a H-bond forms between a cation and anion, and are a key feature of ILs. Doubly ionic H-bonds represent a wide area of H-bonding which has yet to be fully recognised, characterised or explored. H-bonds in ILs (both protic and aprotic) are bifurcated and chelating, and unlike many molecular liquids a significant variety of distinct H-bonds are formed between different types and numbers of donor and acceptor sites within a given IL. Traditional more neutral H-bonds can also be formed in functionalised ILs, adding a further level of complexity. Ab initio computed parameters; association energies, partial charges, density descriptors as encompassed by the QTAIM methodology (ρBCP), qualitative molecular orbital theory and NBO analysis provide established and robust mechanisms for understanding and interpreting traditional neutral and ionic H-bonds. In this review the applicability and extension of these parameters to describe and quantify the doubly ionic H-bond has been explored. Estimating the H-bonding energy is difficult because at a fundamental level the H-bond and ionic interaction are coupled. The NBO and QTAIM methodologies, unlike the total energy, are local descriptors and therefore can be used to directly compare neutral, ionic and doubly ionic H-bonds. The charged nature of the ions influences the ionic characteristics of the H-bond and vice versa, in addition the close association of the ions leads to enhanced orbital overlap and covalent contributions. The charge on the ions raises the energy of the Ylp and lowers the energy of the X-H σ* NBOs resulting in greater charge transfer, strengthening the H-bond. Using this range of parameters and comparing doubly ionic H-bonds to more traditional neutral and ionic H-bonds it is clear that doubly ionic H-bonds cover the full range of weak

Determination of first ionization potential of samarium atom using Rydberg series convergence

International Nuclear Information System (INIS)

Jayasekharan, T.; Razvi, M.A.N.; Bhale, G.L.

1999-01-01

The study of Rydberg states has recently received more attention partially because an efficient isotope selective ionization is possible via these states. In addition, their investigation provides useful information on the atomic structure. An electron in a shell with a high principal quantum number is a sensitive probe for the interaction with the ionic core of the atom. Measurements of these Rydberg levels give valuable data on quantum defects, anomalies in fine structure splitting, polarizabilities, configuration interactions, ionization potentials etc

Tracking Ionic Rearrangements and Interpreting Dynamic Volumetric Changes in Two-Dimensional Metal Carbide Supercapacitors: A Molecular Dynamics Simulation Study.

Science.gov (United States)

Xu, Kui; Lin, Zifeng; Merlet, Céline; Taberna, Pierre-Louis; Miao, Ling; Jiang, Jianjun; Simon, Patrice

2017-12-06

We present a molecular dynamics simulation study achieved on two-dimensional (2D) Ti 3 C 2 T x MXenes in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM] + [TFSI] - ) electrolyte. Our simulations reproduce the different patterns of volumetric change observed experimentally for both the negative and positive electrodes. The analysis of ionic fluxes and structure rearrangements in the 2D material provide an atomic scale insight into the charge and discharge processes in the layer pore and confirm the existence of two different charge-storage mechanisms at the negative and positive electrodes. The ionic number variation and the structure rearrangement contribute to the dynamic volumetric changes of both electrodes: negative electrode expansion and positive electrode contraction. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sensitivities of ionic explosives

Science.gov (United States)

Politzer, Peter; Lane, Pat; Murray, Jane S.

2017-03-01

We have investigated the relevance for ionic explosive sensitivity of three factors that have been demonstrated to be related to the sensitivities of molecular explosives. These are (1) the maximum available heat of detonation, (2) the amount of free space per molecule (or per formula unit) in the crystal lattice and (3) specific features of the electrostatic potential on the molecular or ionic surface. We find that for ionic explosives, just as for molecular ones, there is an overall tendency for impact sensitivity to increase as the maximum detonation heat release is greater. This means that the usual emphasis upon designing explosives with large heats of detonation needs to be tempered somewhat. We also show that a moderate detonation heat release does not preclude a high level of detonation performance for ionic explosives, as was already demonstrated for molecular ones. Relating the free space per formula unit to sensitivity may require a modified procedure for ionic explosives; this will continue to be investigated. Finally, an encouraging start has been made in linking impact sensitivities to the electrostatic potentials on ionic surfaces, although limited so far to ammonium salts.

Strong Stretching of Poly(ethylene glycol) Brushes Mediated by Ionic Liquid Solvation.

Science.gov (United States)

Han, Mengwei; Espinosa-Marzal, Rosa M

2017-09-07

We have measured forces between mica surfaces coated with a poly(ethylene glycol) (PEG) brush solvated by a vacuum-dry ionic liquid, 1-ethyl-3-methyl imidazolium bis(trifluoromethylsulfonyl)imide, with a surface forces apparatus. At high grafting density, the solvation mediated by the ionic liquid causes the brush to stretch twice as much as in water. Modeling of the steric repulsion indicates that PEG behaves as a polyelectrolyte; the hydrogen bonding between ethylene glycol and the imidazolium cation seems to effectively charge the polymer brush, which justifies the strong stretching. Importantly, under strong polymer compression, solvation layers are squeezed out at a higher rate than for the neat ionic liquid. We propose that the thermal fluctuations of the PEG chains, larger in the brush than in the mushroom configuration, maintain the fluidity of the ionic liquid under strong compression, in contrast to the solid-like squeezing-out behavior of the neat ionic liquid. This is the first experimental study of the behavior of a polymer brush solvated by an ionic liquid under nanoconfinement.

Influence of the ionic liquid 1-butyl-3-methylimidazolium bromide on amyloid fibrillogenesis in lysozyme: Evidence from photophysical and imaging studies.

Science.gov (United States)

Basu, Anirban; Bhattacharya, Subhash Chandra; Kumar, Gopinatha Suresh

2018-02-01

Many proteins can abnormally fold to form pathological amyloid deposits/aggregates that are responsible for various degenerative disorders called amyloidosis. Here we have examined the anti-amyloidogenic potency of an ionic liquid, 1-butyl-3-methylimidazolium bromide, using lysozyme as a model system. Thioflavin T fluorescence assay demonstrated that the ionic liquid suppressed the formation of lysozyme fibrils significantly. This observation was further confirmed by the Congo red assay. Fluorescence microscopy, intrinsic fluorescence studies, nile red fluorescence assay, ANS binding assay and circular dichroism studies also testified diminishing of the fibrillogenesis in the presence of ionic liquid. Formation of amyloid fibrils was also characterized by α to β conformational transition. From far-UV circular dichroism studies it was observed that the β-sheet content of the lysozyme samples decreased in the presence of the ionic liquid which in turn implied that fibrillogenesis was supressed by the ionic liquid. Atomic force microscopy imaging unequivocally established that the ionic liquid attenuated fibrillogenesis in lysozyme. These results may be useful for the development of more effective therapeutics for amyloidosis. Copyright © 2017 Elsevier B.V. All rights reserved.

Graphene-ionic liquid composites

Energy Technology Data Exchange (ETDEWEB)

Aksay, Ilhan A.; Korkut, Sibel; Pope, Michael; Punckt, Christian

2016-11-01

Method of making a graphene-ionic liquid composite. The composite can be used to make elec-trodes for energy storage devices, such as batteries and supercapacitors. Dis-closed and claimed herein is method of making a graphene-ionic liquid com-posite, comprising combining a graphene source with at least one ionic liquid and heating the combination at a temperature of at least about 130 .degree. C.

Critical osmotic, ionic and physiological indicators of salinity tolerance in cotton (gossypium hirsutum l.) for cultivar selection

International Nuclear Information System (INIS)

Munis, M.F.H.; Tu, L.; Ziaf, K; Tan, J.; Deng, F.; Zhang, X.

2010-01-01

Salinity affects the germination, growth and ultimately the yield of cotton (Gossypium hirsutum L.) which demands reliable traits for the evaluation and selection of salt tolerant cultivars. Here, ten major osmotic, ionic and physiological parameters have been studied to distinguish the effect of salinity in two different cultivars of cotton. Plants were grown in hydroponic system and exposed to different salinity levels of NaCl followed by its recovery under non saline conditions. Data was recorded at three different stages i.e., before stress, after stress and after recovery for comparative study. Recovery assay proved to be very helpful in extracting reliable results. Both cultivars showed significantly different response to Na+ and K+ accumulation and phenotypically salt tolerant cultivar (Coker 312) accumulated less Na+ and more K+ in comparison with susceptible (Simian 3). Decrease in leaf area, seed germination and seedling growth were also conclusive to differentiate these cultivars. We also found other physiological parameters like relative leaf water content (RLWC), plant fresh-weight (PFW), plant dry-weight (PDW), relative growth rate (RGR) and stomatal behavior as good indicators of salinity but could not find their significant role to differentiate two closely relevant cultivars regarding salinity tolerance. Our studies revealed that proline accumulation and chlorophyll concentration are not significant to be used as accurate indicators to characterize the sensitivity of cotton cultivars to salinity. We found post-recovery analysis to be very useful in understanding the role and behavior of different indicators of salinity. (author)

The new NIST atomic spectra database

International Nuclear Information System (INIS)

Kelleher, D.E.; Martin, W.C.; Wiese, W.L.; Sugar, J.; Fuhr, J.R.; Olsen, K.; Musgrove, A.; Mohr, P.J.; Reader, J.; Dalton, G.R.

1999-01-01

The new atomic spectra database (ASD), Version 2.0, of the National Institute of Standards and Technology (NIST) contains significantly more data and covers a wider range of atomic and ionic transitions and energy levels than earlier versions. All data are integrated. It also has a new user interface and search engine. ASD contains spectral reference data which have been critically evaluated and compiled by NIST. Version 2.0 contains data on 900 spectra, with about 70000 energy levels and 91000 lines ranging from about 1 Aangstroem to 200 micrometers, roughly half of which have transition probabilities with estimated uncertainties. References to the NIST compilations and original data sources are listed in the ASD bibliography. A detailed ''Help'' file serves as a user's manual, and full search and filter capabilities are provided. (orig.)

Anomalous frequency-dependent ionic conductivity of lesion-laden human-brain tissue

Science.gov (United States)

Emin, David; Akhtari, Massoud; Fallah, Aria; Vinters, Harry V.; Mathern, Gary W.

2017-10-01

We study the effect of lesions on our four-electrode measurements of the ionic conductivity of (˜1 cm3) samples of human brain excised from patients undergoing pediatric epilepsy surgery. For most (˜94%) samples, the low-frequency ionic conductivity rises upon increasing the applied frequency. We attributed this behavior to the long-range (˜0.4 mm) diffusion of solvated sodium cations before encountering intrinsic impenetrable blockages such as cell membranes, blood vessels, and cell walls. By contrast, the low-frequency ionic conductivity of some (˜6%) brain-tissue samples falls with increasing applied frequency. We attribute this unusual frequency-dependence to the electric-field induced liberation of sodium cations from traps introduced by the unusually severe pathology observed in samples from these patients. Thus, the anomalous frequency-dependence of the ionic conductivity indicates trap-producing brain lesions.

Activated carbons employed to remove ionic liquids from aqueous solutions

International Nuclear Information System (INIS)

Hassan, S.; Farooq, A.; Ahmad, M.A.; Irfan, N.; Tufail, M.

2011-01-01

Imidazolium and pyridinium based ionic liquids (ILs) have been separated from aqueous solutions by adsorption using a raw Chinese activated carbon (CAC), a bleached Chinese activated carbon (BAC) and an acid treated Chinese activated carbon (AAC) as adsorbent. Adsorption isotherms data of ionic liquids on activated carbons has been obtained. The influence of both cations and anions was analyzed by studying three different ILs. The role of surface chemistry of the adsorbent was also examined using activated carbons modified by oxidative treatments. The BET surface area of activated carbons was measured by nitrogen adsorption. The results of this work indicate that activated carbon is an attractive adsorbent to remove ionic liquids from water streams. It has also been demonstrated that the adsorption of hydrophilic ionic liquids can be improved by modifying the amount and nature of oxygen groups on the activated carbon surface specially by increasing basic groups. The adsorption data for isotherms was studied at acidic, neutral and basic pH values. (author)

Ionic conductivity of polymer gels deriving from alkali metal ionic liquids and negatively charged polyelectrolytes

International Nuclear Information System (INIS)

Ogihara, Wataru; Sun Jiazeng; Forsyth, Maria; MacFarlane, Douglas R.; Yoshizawa, Masahiro; Ohno, Hiroyuki

2004-01-01

We have prepared polymer gel electrolytes with alkali metal ionic liquids (AMILs) that inherently contain alkali metal ions. The AMIL consisted of sulfate anion, imidazolium cation, and alkali metal cation. AMILs were mixed directly with poly(3-sulfopropyl acrylate) lithium salt or poly(2-acrylamido-2-methylpropanesulfonic acid) lithium salt to form polymer gels. The ionic conductivity of these gels decreased with increasing polymer fraction, as in general ionic liquid/polymer mixed systems. At low polymer concentrations, these gels displayed excellent ionic conductivity of 10 -4 to 10 -3 S cm -1 at room temperature. Gelation was found to cause little change in the 7 Li diffusion coefficient of the ionic liquid, as measured by pulse-field-gradient NMR. These data strongly suggest that the lithium cation migrates in successive pathways provided by the ionic liquids

Reactivity of amino acid anions with nitrogen and oxygen atoms.

Science.gov (United States)

Wang, Zhe-Chen; Li, Ya-Ke; He, Sheng-Gui; Bierbaum, Veronica M

2018-02-14

For many decades, astronomers have searched for biological molecules, including amino acids, in the interstellar medium; this endeavor is important for investigating the hypothesis of the origin of life from space. The space environment is complex and atomic species, such as nitrogen and oxygen atoms, are widely distributed. In this work, the reactions of eight typical deprotonated amino acids (glycine, alanine, cysteine, proline, aspartic acid, histidine, tyrosine, and tryptophan) with ground state nitrogen and oxygen atoms are studied by experiment and theory. These amino acid anions do not react with nitrogen atoms. However, the reactions of these ions with oxygen atoms show an intriguing variety of ionic products and the reaction rate constants are of the order of 10 -10 cm 3 s -1 . Density functional calculations provide detailed mechanisms of the reactions, and demonstrate that spin conversion is essential for some processes. Our study provides important data and insights for understanding the kinetic and dynamic behavior of amino acids in space environments.

Ionic liquid-assisted multiwalled carbon nanotube-dispersive micro-solid phase extraction for sensitive determination of inorganic As species in garlic samples by electrothermal atomic absorption spectrometry

Science.gov (United States)

Grijalba, Alexander Castro; Escudero, Leticia B.; Wuilloud, Rodolfo G.

2015-08-01

A highly sensitive dispersive micro-solid phase extraction (D-μ-SPE) method combining an ionic liquid (IL) and multi-walled carbon nanotubes (MWCNTs) for inorganic As species (As(III) and As(V)) species separation and determination in garlic samples by electrothermal atomic absorption spectrometry (ETAAS) was developed. Trihexyl(tetradecil)phosphonium chloride IL was used to form an ion pair with the arsenomolybdate complex obtained by reaction of As(V) with molybdate ion. Afterwards, 1.0 mg of MWCNTs was dispersed for As(V) extraction and the supernatant was separated by centrifugation. MWCNTs were re-dispersed with tetradecyltrimethylammonium bromide surfactant and ultrasound followed by direct injection into the graphite furnace of ETAAS for As determination. Pyrolysis and atomization conditions were carefully studied for complete decomposition of MWCNTs and IL matrices. Under optimum conditions, an extraction efficiency of 100% and a preconcentration factor of 70 were obtained with 5 mL of garlic extract. The detection limit was 7.1 ng L- 1 and the relative standard deviations (RSDs) for six replicate measurements at 5 μg L- 1 of As were 5.4% and 4.8% for As(III) and As(V), respectively. The proposed D-μ-SPE method allowed the efficient separation and determination of inorganic As species in a complex matrix such as garlic extract.

Effect of the alkyl chain length of the ionic liquid anion on polymer electrolytes properties

International Nuclear Information System (INIS)

Leones, Rita; Sentanin, Franciani; Nunes, Sílvia Cristina; Esperança, José M.S.S.; Gonçalves, Maria Cristina

2015-01-01

New polymer electrolytes (PEs) based on chitosan and three ionic liquid (IL) families ([C 2 mim][C n SO 3 ], [C 2 mim][C n SO 4 ] and [C 2 mim][diC n PO 4 ]) were synthesized by the solvent casting method. The effect of the length of the alkyl chain of the IL anion on the thermal, morphological and electrochemical properties of the PEs was studied. The solid polymer electrolytes SPE membranes were analyzed by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), polarized optical microscopy (POM), atomic force microscopy (AFM), complex impedance spectroscopy (ionic conductivity) and cyclic voltammetry (CV). The obtained results evidenced an influence of the alkyl chain length of the IL anion on the temperature of degradation, birefringence, surface roughness and ionic conductivity of the membranes. The DSC, XRD and CV results showed independency from the length of the IL-anion-alkyl chain. The PEs displayed an predominantly amorphous morphology, a minimum temperature of degradation of 135 °C, a room temperature (T = 25 °C) ionic conductivity of 7.78 × 10 −4 S cm −1 and a wide electrochemical window of ∼ 4.0 V.

Functional ionic liquids

International Nuclear Information System (INIS)

Baecker, Tobias

2012-01-01

In the thesis at hand, new functional ionic liquids were investigated. Main focus was attended to their structure property relations and the structural features leading to a decrease of the melting point. New compounds of the type 1-butyl-3-methylimidazolium tris(N,Ndialkyldithiocarbamato) uranylate with variously substituated dithiocarbamato ligands were synthesized and characterized. Ligands with asymmetrical substitution pattern proved to be most suitable for ionic liquid formation. The single-crystal X-ray structures revealed the interactions in the solid state. Here, the first spectroscopic investigation of the U-S bond in sulfur donated uranyl complexes, up to now only observed in single-crystal X-ray structures, is presented, and the participation of the uranium f-orbitals is shown by theoretical calculations. Electrochemical investigations showed the accessibility of the respective U V O 2 + compounds. As well, ionic liquids with [FeCl 4 ] - and [Cl 3 FeOFeCl 3 ] 2- as anion were synthesized. Both of these anions contain high-spin Fe(III) centres in distorted tetrahedral environment, but exhibit different magnetic behaviour. The tetrachloroferrates show the usual paramagnetism, the m-oxobis(trichloroferrate) exhibits unexpectedly strong antiferromagnetic coupling, as was observed by NMR experiments and susceptibility measurements. To investigate structure-property relations in functionalized ionic liquids, a set of protic, primary alkylammonium and aprotic, quarternary trimethylalkylammonium based ionic liquids was synthesized, and characterized. The length of the alkyl chain was systematically varied, and all compounds were synthesized with and without hydroxyl group, as well as formate and bis(triflyl)amide salts, aiming at getting insight into the influence of the different structure parts on the respective ionic liquid's properties.

Chemical Structure and Properties: A Modified Atoms-First, One-Semester Introductory Chemistry Course

Science.gov (United States)

Schaller, Chris P.; Graham, Kate J.; Johnson, Brian J.; Jakubowski, Henry V.; McKenna, Anna G.; McIntee, Edward J.; Jones, T. Nicholas; Fazal, M. A.; Peterson, Alicia A.

2015-01-01

A one-semester, introductory chemistry course is described that develops a primarily qualitative understanding of structure-property relationships. Starting from an atoms-first approach, the course examines the properties and three-dimensional structure of metallic and ionic solids before expanding into a thorough investigation of molecules. In…

Ionic strength-induced formation of smectite quasicrystals enhances nitroaromatic compound sorption.

Science.gov (United States)

Li, Hui; Pereira, Tanya R; Teppen, Brian J; Laird, David A; Johnston, Cliff T; Boyd, Stephen A

2007-02-15

Sorption of organic contaminants by soils is a determinant controlling their transport and fate in the environment. The influence of ionic strength on nitroaromatic compound sorption by K+- and Ca2+ -saturated smectite was examined. Sorption of 1,3-dinitrobenzene by K-smectite increased as KCl ionic strength increased from 0.01 to 0.30 M. In contrast, sorption by Ca-smectite at CaCl2 ionic strengths of 0.015 and 0.15 M remained essentially the same. The "salting-out" effect on the decrease of 1,3-dinitrobenzene aqueous solubility within this ionic strength range was smectite with increasing KCl ionic strength. X-ray diffraction patterns and light absorbance of K-clay suspensions indicated the aggregation of clay particles and the formation of quasicrystal structures as KCI ionic strength increased. Sorption enhancement is attributed to the formation of better-ordered K-clay quasicrystals with reduced interlayer distances rather than to the salting-out effect. Dehydration of 1,3-dinitrobenzene is apparently a significant driving force for sorption, and we show for the first time that sorption of small, planar, neutral organic molecules, namely, 1,3-dinitrobenzene, causes previously expanded clay interlayers to dehydrate and collapse in aqueous suspension.

Point defects and atomic transport in crystals

International Nuclear Information System (INIS)

Lidiard, A.B.

1981-02-01

There are two principle aspects to the theory of atomic transport in crystals as caused by the action of point defects, namely (1) the calculation of relevant properties of the point defects (energies and other thermodynamic characteristics of the different possible defects, activation energies and other mobility parameters) and (2) the statistical mechanics of assemblies of defects, both equilibrium and non-equilibrium assemblies. In the five lectures given here both these aspects are touched on. The first two lectures are concerned with the calculation of relevant point defect properties, particularly in ionic crystals. The first lecture is more general, the second is concerned particularly with some recent calculations of the free volumes of formation of defects in various ionic solids; these solve a rather long-standing problem in this area. The remaining three lectures are concerned with the kinetic theory of defects mainly in relaxation, drift and diffusion situations

Glass Transitions and Low-Frequency Dynamics of Room-Temperature Ionic Liquids

International Nuclear Information System (INIS)

Yamamuro, O.; Inamura, Y.; Hayashi, S.; Hamaguchi, H.

2006-01-01

We have measured the heat capacity and neutrion quasi- and inelastic scattering spectra of some salts of 1-butyl-3-methylimidazolium ion bmim+, which is a typical cation of room-temperature ionic liquids, and its derivatives. The heat capacity measurements revealed that the room-temperature ionic liquids have glass transitions as molecular liquids. The temperature dependence of configurational entropy demonstrated that the room-temperature ionic liquids are 'fragile liquids'. Both heat capacity and inelastic neutron scattering data revealed that the glassy phases exhibit large low-energy excitations usually called 'boson peak'. The quasielastic neutron scattering data showed that so-called 'fast process' appears around Tg as in molecular and polymer glasses. The temperature dependence of the self-diffusion coefficient derived from the neutron scattering data indicated that the orientation of bmim+ ions and/or butyl-groups of bmim+ ions is highly disordered and very flexible in an ionic liquid phase

Ionic liquid-modified metal sulfides/graphene oxide nanocomposites for photoelectric conversion

International Nuclear Information System (INIS)

Zhang, Yu; Zhang, Yù; Pei, Qi; Feng, Ting; Mao, Hui; Zhang, Wei; Wu, Shuyao; Liu, Daliang; Wang, Hongyu; Song, Xi-Ming

2015-01-01

Graphical abstract: - Highlights: • Metal sulfide (CdS, ZnS, Ag 2 S)/GO nanocomposites were prepared by electrostatic adherence. • Ionic liquid was used to link the metal sulfide and GO in the electrostatic adherence process. • The as-prepared samples showed enhanced photocurrent and highly efficient photocatalytic activity under visible light irradiation. - Abstract: Ionic liquid-modified metal sulfides/graphene oxide nanocomposites are prepared via a facile electrostatic adsorption. Ionic liquid (IL) is firstly used as surface modifier and structure-directing agent of metal sulfide (MS) crystallization process, obtaining ionic liquid modified-MS (IL-MS) nanoparticles with positive charges on surface. IL-MS/GO is obtained by electrostatic adherence between positively charged IL-MS and negatively charged graphene oxide (GO). The as-prepared sample shows enhanced photocurrent and highly efficient photocatalytic activity under visible light irradiation, indicating IL-MS/GO nanocomposites greatly promoted the separation of photogenerated electron–hole pairs

Quantitative Determination on Ionic-Liquid-Gating Control of Interfacial Magnetism.

Science.gov (United States)

Zhao, Shishun; Zhou, Ziyao; Peng, Bin; Zhu, Mingmin; Feng, Mengmeng; Yang, Qu; Yan, Yuan; Ren, Wei; Ye, Zuo-Guang; Liu, Yaohua; Liu, Ming

2017-05-01

Ionic-liquid gating on a functional thin film with a low voltage has drawn a lot of attention due to rich chemical, electronic, and magnetic phenomena at the interface. Here, a key challenge in quantitative determination of voltage-controlled magnetic anisotropy (VCMA) in Au/[DEME] + [TFSI] - /Co field-effect transistor heterostructures is addressed. The magnetic anisotropy change as response to the gating voltage is precisely detected by in situ electron spin resonance measurements. A reversible change of magnetic anisotropy up to 219 Oe is achieved with a low gating voltage of 1.5 V at room temperature, corresponding to a record high VCMA coefficient of ≈146 Oe V -1 . Two gating effects, the electrostatic doping and electrochemical reaction, are distinguished at various gating voltage regions, as confirmed by X-ray photoelectron spectroscopy and atomic force microscopy experiments. This work shows a unique ionic-liquid-gating system for strong interfacial magnetoelectric coupling with many practical advantages, paving the way toward ion-liquid-gating spintronic/electronic devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sub-nanomolar sensing of ionic mercury with polymeric electrospun nanofibers

Energy Technology Data Exchange (ETDEWEB)

Kacmaz, Sibel [University of Dokuz Eylul, The Graduate School of Natural and Applied Sciences, Department of Chemistry, 35160 Izmir (Turkey); Ertekin, Kadriye, E-mail: kadriye.ertekin@deu.edu.tr [University of Dokuz Eylul, Faculty of Sciences, Department of Chemistry, 35160 Izmir (Turkey); University of Dokuz Eylul, Center for Fabrication and Application of Electronic Materials (EMUM), 35160 Izmir (Turkey); Suslu, Aslihan [University of Dokuz Eylul, The Graduate School of Natural and Applied Sciences, Department of Chemistry, 35160 Izmir (Turkey); University of Dokuz Eylul, Faculty Engineering, Department of Metallurgical and Materials Engineering, 35160 Izmir (Turkey); Ergun, Yavuz [University of Dokuz Eylul, Faculty of Sciences, Department of Chemistry, 35160 Izmir (Turkey); Celik, Erdal [University of Dokuz Eylul, Center for Fabrication and Application of Electronic Materials (EMUM), 35160 Izmir (Turkey); University of Dokuz Eylul, Faculty Engineering, Department of Metallurgical and Materials Engineering, 35160 Izmir (Turkey); Cocen, Umit [University of Dokuz Eylul, Faculty Engineering, Department of Metallurgical and Materials Engineering, 35160 Izmir (Turkey)

2012-03-15

Ethyl cellulose (EC) based electrospun nanofibers were exploited for sub-nanomolar level optical chemical sensing of ionic mercury. An azomethine ionophore was used as Hg (I) and Hg (II) sensing material. Ethyl cellulose nanofibers with varying amounts of the ionic liquid; 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF{sub 4}) were prepared and characterized. The nanofibers were fabricated by electrospinning technique. The offered chemosensor allow determination of mercury ions in a large linear working range between 1.0 Multiplication-Sign 10{sup -10} and 1.0 Multiplication-Sign 10{sup -4} mol L{sup -1}. Limit of detection was found to be 0.07 nM which makes this technique alternative to cold-vapor atomic absorption spectrometry (CV-AAS), flame emission methods and to inductively coupled plasma-mass spectrometry (ICP-MS). The electrospun nanofibers exhibited excellent sensitivity for Hg (II) with respect to the continuous thin films prepared with same composition. The observed high sensitivity can be attributed to the high surface area of the nanofibrous materials and enhanced diffusibility of the mercury ions to the ionophore.

Selective determination of inorganic cobalt in nutritional supplements by ultrasound-assisted temperature-controlled ionic liquid dispersive liquid phase microextraction and electrothermal atomic absorption spectrometry

International Nuclear Information System (INIS)

Berton, Paula; Martinis, Estefanía M.; Martinez, Luis D.; Wuilloud, Rodolfo G.

2012-01-01

Highlights: ► Synergy of ultrasound energy and TILDLME technique for improved metal extraction. ► Highly selective determination of inorganic Co species at trace levels. ► Speciation analysis of Co in several nutritional supplements with highly complex matrices. ► Development of an environmentally friendly microextraction technique with minimal waste production and sample consumption. - Abstract: In the present work, a simple and rapid analytical method based on application of ionic liquids (ILs) for inorganic Co(II) species (iCo) microextraction in a variety of nutrient supplements was developed. Inorganic Co was initially chelated with 1-nitroso-2-naphtol (1N2N) reagent followed by a modern technique named ultrasound-assisted temperature-controlled ionic liquid dispersive liquid phase microextraction (USA-TILDLME). The extraction was performed with 1-hexyl-3-methylimidazolium hexafluorophosphate [C 6 mim][PF 6 ] with the aid of ultrasound to improve iCo recovery. Finally, the iCo-enriched IL phase was solubilized in methanol and directly injected into an electrothermal atomic absorption spectrometer (ETAAS). Several parameters that could influence iCo microextraction and detection were carefully studied. Since the main difficulty in these samples is caused by high concentrations of potential interfering ions, different approaches were evaluated to eliminate interferences. The limit of detection (LOD) was 5.4 ng L −1 , while the relative standard deviation (RSD) was 4.7% (at 0.5 μg L −1 Co level and n = 10), calculated from the peak height of absorbance signals. Selective microextraction of iCo species was achieved only by controlling the pH value during the procedure. The method was thus successfully applied for determination of iCo species in nutritional supplements.

Ionic liquid-based ultrasound-assisted dispersive liquid-liquid microextraction combined with electrothermal atomic absorption spectrometry for a sensitive determination of cadmium in water samples

International Nuclear Information System (INIS)

Li Shengqing; Cai Shun; Hu Wei; Chen Hao; Liu Hanlan

2009-01-01

A new method was developed for the determination of cadmium in water samples using ionic liquid-based ultrasound-assisted dispersive liquid-liquid microextraction (IL-based USA-DLLME) followed by electrothermal atomic absorption spectrometry (ETAAS). The IL-based USA-DLLME procedure is free of volatile organic solvents, and there is no need for a dispersive solvent, in contrast to conventional DLLME. The ionic liquid, 1-hexyl-3-methylimidazolium hexafluorophosphate (HMIMPF 6 ), was quickly disrupted by an ultrasonic probe for 1 min and dispersed in water samples like a cloud. At this stage, a hydrophobic cadmium-DDTC complex was formed and extracted into the fine droplets of HMIMPF 6 . After centrifugation, the concentration of the enriched cadmium in the sedimented phase was determined by ETAAS. Some effective parameters of the complex formation and microextraction, such as the concentration of the chelating agent, the pH, the volume of the extraction solvent, the extraction time, and the salt effect, have been optimized. Under optimal conditions, a high extraction efficiency and selectivity were reached for the extraction of 1.0 ng of cadmium in 10.0 mL of water solution employing 73 μL of HMIMPF 6 as the extraction solvent. The enrichment factor of the method is 67. The detection limit was 7.4 ng L - 1 , and the characteristic mass (m 0 , 0.0044 absorbance) of the proposed method was 0.02 pg for cadmium (Cd). The relative standard deviation (RSD) for 11 replicates of 50 ng L - 1 Cd was 3.3%. The method was applied to the analysis of tap, well, river, and lake water samples and the Environmental Water Reference Material GSBZ 50009-88 (200921). The recoveries of spiked samples were in the range of 87.2-106%.

Selective determination of inorganic cobalt in nutritional supplements by ultrasound-assisted temperature-controlled ionic liquid dispersive liquid phase microextraction and electrothermal atomic absorption spectrometry

Energy Technology Data Exchange (ETDEWEB)

Berton, Paula; Martinis, Estefania M. [Analytical Chemistry Research and Development Group (QUIANID), (LISAMEN-CCT-CONICET-Mendoza), Av. Ruiz Leal S/N Parque General San Martin, M 5502 IRA Mendoza (Argentina); Martinez, Luis D. [INQUISAL-CONICET, Departamento de Quimica Analitica, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, San Luis (Argentina); Wuilloud, Rodolfo G., E-mail: rwuilloud@mendoza-conicet.gob.ar [Analytical Chemistry Research and Development Group (QUIANID), (LISAMEN-CCT-CONICET-Mendoza), Av. Ruiz Leal S/N Parque General San Martin, M 5502 IRA Mendoza (Argentina); Instituto de Ciencias Basicas, Universidad Nacional de Cuyo, Mendoza (Argentina)

2012-02-03

Highlights: Black-Right-Pointing-Pointer Synergy of ultrasound energy and TILDLME technique for improved metal extraction. Black-Right-Pointing-Pointer Highly selective determination of inorganic Co species at trace levels. Black-Right-Pointing-Pointer Speciation analysis of Co in several nutritional supplements with highly complex matrices. Black-Right-Pointing-Pointer Development of an environmentally friendly microextraction technique with minimal waste production and sample consumption. - Abstract: In the present work, a simple and rapid analytical method based on application of ionic liquids (ILs) for inorganic Co(II) species (iCo) microextraction in a variety of nutrient supplements was developed. Inorganic Co was initially chelated with 1-nitroso-2-naphtol (1N2N) reagent followed by a modern technique named ultrasound-assisted temperature-controlled ionic liquid dispersive liquid phase microextraction (USA-TILDLME). The extraction was performed with 1-hexyl-3-methylimidazolium hexafluorophosphate [C{sub 6}mim][PF{sub 6}] with the aid of ultrasound to improve iCo recovery. Finally, the iCo-enriched IL phase was solubilized in methanol and directly injected into an electrothermal atomic absorption spectrometer (ETAAS). Several parameters that could influence iCo microextraction and detection were carefully studied. Since the main difficulty in these samples is caused by high concentrations of potential interfering ions, different approaches were evaluated to eliminate interferences. The limit of detection (LOD) was 5.4 ng L{sup -1}, while the relative standard deviation (RSD) was 4.7% (at 0.5 {mu}g L{sup -1} Co level and n = 10), calculated from the peak height of absorbance signals. Selective microextraction of iCo species was achieved only by controlling the pH value during the procedure. The method was thus successfully applied for determination of iCo species in nutritional supplements.

Structure, ionic Conductivity and mobile Carrier Density in Fast Ionic Conducting Chalcogenide Glasses

International Nuclear Information System (INIS)

Wenlong Yao

2006-01-01

This thesis consists of six sections. The first section gives the basic research background on the ionic conduction mechanism in glass, polarization in the glass, and the method of determining the mobile carrier density in glass. The proposed work is also included in this section. The second section is a paper that characterizes the structure of MI + M 2 S + (0.1 Ga 2 S 3 + 0.9 GeS 2 ) (M = Li, Na, K and Cs) glasses using Raman and IR spectroscopy. Since the ionic radius plays an important role in determining the ionic conductivity in glasses, the glass forming range for the addition of different alkalis into the basic glass forming system 0.1 Ga 2 S 3 + 0.9 GeS 2 was studied. The study found that the change of the alkali radius for the same nominal composition causes significant structure change to the glasses. The third section is a paper that investigates the ionic conductivity of MI + M 2 S + (0.1Ga 2 S 3 + 0.9 GeS 2 ) (M = Li, Na, K and Cs) glasses system. Corresponding to the compositional changes in these fast ionic conducting glasses, the ionic conductivity shows changes due to the induced structural changes. The ionic radius effect on the ionic conductivity in these glasses was investigated. The fourth section is a paper that examines the mobile carrier density based upon the measurements of space charge polarization. For the first time, the charge carrier number density in fast ionic conducting chalcogenide glasses was determined. The experimental impedance data were fitted using equivalent circuits and the obtained parameters were used to determine the mobile carrier density. The influence of mobile carrier density and mobility on the ionic conductivity was separated. The fifth section is a paper that studies the structures of low-alkali-content Na 2 S + B 2 S 3 (x (le) 0.2) glasses by neutron and synchrotron x-ray diffraction. Similar results were obtained both in neutron and synchrotron x-ray diffraction experiments. The results provide direct

Entanglement of mixed quantum states for qubits and qudit in double photoionization of atoms

Energy Technology Data Exchange (ETDEWEB)

Chakraborty, M., E-mail: bminakshi@yahoo.com [Department of Physics, Asansol Girls’ College, Asansol 713304 (India); Sen, S. [Department of Physics, Triveni Devi Bhalotia College, Raniganj 713347 (India)

2015-08-15

Highlights: • We study tripartite entanglement between two electronic qubits and an ionic qudit. • We study bipartite entanglement between any two subsystems of a tripartite system. • We have presented a quantitative application of entangled properties in Neon atom. - Abstract: Quantum entanglement and its paradoxical properties are genuine physical resources for various quantum information tasks like quantum teleportation, quantum cryptography, and quantum computer technology. The physical characteristic of the entanglement of quantum-mechanical states, both for pure and mixed, has been recognized as a central resource in various aspects of quantum information processing. In this article, we study the bipartite entanglement of one electronic qubit along with the ionic qudit and also entanglement between two electronic qubits. The tripartite entanglement properties also have been investigated between two electronic qubits and an ionic qudit. All these studies have been done for the single-step double photoionization from an atom following the absorption of a single photon without observing spin orbit interaction. The dimension of the Hilbert space of the qudit depends upon the electronic state of the residual photoion A{sup 2+}. In absence of SOI, when Russell–Saunders coupling (L–S coupling) is applicable, dimension of the qudit is equal to the spin multiplicity of A{sup 2+}. For estimations of entanglement and mixedness, we consider the Peres–Horodecki condition, concurrence, entanglement of formation, negativity, linear and von Neumann entropies. In case of L–S coupling, all the properties of a qubit–qudit system can be predicted merely with the knowledge of the spins of the target atom and the residual photoion.

Ionic and non-ionic contrast media used for contrast-enhanced computed tomography in experimental pancreatitis

International Nuclear Information System (INIS)

Kivisaari, L.; Nuutinen, P.; Lehtola, A.; Saari, A.; Pitkaeranta, P.; Standertskjoeld-Nordenstam, C.G.; Lempinen, M.; Schroeder, T.; Helsinki Univ. Central Hospital

1988-01-01

Contrast enhancement of the pancreas was studied in pigs using dynamic computed tomography in experimental oedematous and haemorrhagic/necrotizing pancreatitis during the first two minutes after injection of an intravenous bolus of non-ionic contrast medium (iohexol). The prospects of separating the two forms of the disease, known to be possible with ionic contrast media, were tested with a non-ionic contrast medium. In the oedematous form, contrast enhancement after 5 hours of the disease was significantly higher than in the haemorrhagic/necrotizing form. Contrast enhancement after 30 hours of disease tended to vary with the severity of the disease, showing that the course of oedematous pancreatitis is dynamic. Intermediate forms occur and follow-up studies are needed during the disease. A non-ionic contrast medium proved as good for separating the two forms of the disease in the early phase as were ionic contrast media. In severely ill patients, non-ionic contrast media should therefore be used. (orig.)

A density functional theory study on the interactions between dibenzothiophene and tetrafluoroborate-based ionic liquids.

Science.gov (United States)

Lin, Jin; Lü, Renqing; Wu, Chongchong; Xiao, Ye; Liang, Fei; Famakinwa, Temilola

2017-04-01

The interactions between dibenzothiophene (DBT) and N-butyl-N-methylimidazolium tetrafluoroborate ([BMIM][BF 4 ]), N-butyl-N-methylmorpholinium tetrafluoroborate ([Bmmorpholinium][BF 4 ]), N-butyl-N-methylpiperdinium tetrafluoroborate ([BMPiper][BF 4 ]), N-butyl-N-methylpyrrolidinium tetrafluoroborate ([BMPyrro][BF 4 ]), and N-butylpyridinium tetrafluoroborate ([BPY][BF 4 ]) were investigated using density functional theory approach. Geometric, electron, and topological properties were analyzed using natural bond orbital, atoms in molecules theory, and noncovalent interaction methods in order to understand intermolecular interactions between DBT and ionic liquids. The result shows that hydrogen bond and van der Waals interactions are widespread in all the ionic liquids-DBT systems. Ion-π interactions between DBT and cation or anion are also observed, while π + -π interactions are only found in the [BMIM][BF 4 ]-DBT and [BPY][BF 4 ]-DBT systems. The order of interaction energy is [BPY][BF4]-DBT > [BMIM][BF 4 ]-DBT > [BMPiper][BF 4 ]-DBT > [BMPyrro][BF 4 ]-DBT > [BMmorpholinum][BF 4 ]-DBT. The energies between DBT and the two ionic liquids containing aromatic cations are significantly higher.

Nanoparticles in ionic liquids: interactions and organization.

Science.gov (United States)

He, Zhiqi; Alexandridis, Paschalis

2015-07-28

Ionic liquids (ILs), defined as low-melting organic salts, are a novel class of compounds with unique properties and a combinatorially great chemical diversity. Ionic liquids are utilized as synthesis and dispersion media for nanoparticles as well as for surface functionalization. Ionic liquid and nanoparticle hybrid systems are governed by a combined effect of several intermolecular interactions between their constituents. For each interaction, including van der Waals, electrostatic, structural, solvophobic, steric, and hydrogen bonding, the characterization and quantitative calculation methods together with factors affecting these interactions are reviewed here. Various self-organized structures based on nanoparticles in ionic liquids are generated as a result of a balance of these intermolecular interactions. These structures, including colloidal glasses and gels, lyotropic liquid crystals, nanoparticle-stabilized ionic liquid-containing emulsions, ionic liquid surface-functionalized nanoparticles, and nanoscale ionic materials, possess properties of both ionic liquids and nanoparticles, which render them useful as novel materials especially in electrochemical and catalysis applications. This review of the interactions within nanoparticle dispersions in ionic liquids and of the structure of nanoparticle and ionic liquid hybrids provides guidance on the rational design of novel ionic liquid-based materials, enabling applications in broad areas.

Trace mercury determination in drinking and natural water samples by room temperature ionic liquid based-preconcentration and flow injection-cold vapor atomic absorption spectrometry.

Science.gov (United States)

Martinis, Estefanía M; Bertón, Paula; Olsina, Roberto A; Altamirano, Jorgelina C; Wuilloud, Rodolfo G

2009-08-15

A liquid-liquid extraction procedure (L-L) based on room temperature ionic liquid (RTIL) was developed for the preconcentration and determination of mercury in different water samples. The analyte was quantitatively extracted with 1-butyl-3-methylimidazolium hexafluorophosphate ([C(4)mim][PF(6)]) under the form of Hg-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Hg-5-Br-PADAP) complex. A volume of 500 microl of 9.0 mol L(-1) hydrochloric acid was used to back-extract the analyte from the RTIL phase into an aqueous media prior to its analysis by flow injection-cold vapor atomic absorption spectrometry (FI-CV-AAS). A preconcentration factor of 36 was achieved upon preconcentration of 20 mL of sample. The limit of detection (LOD) obtained under the optimal conditions was 2.3ngL(-1) and the relative standard deviation (RSD) for 10 replicates at 1 microg L(-1) Hg(2+) was 2.8%, calculated with peaks height. The method was successfully applied to the determination of mercury in river, sea, mineral and tap water samples and a certified reference material (CRM).

Trace mercury determination in drinking and natural water samples by room temperature ionic liquid based-preconcentration and flow injection-cold vapor atomic absorption spectrometry

International Nuclear Information System (INIS)

Martinis, Estefania M.; Berton, Paula; Olsina, Roberto A.; Altamirano, Jorgelina C.; Wuilloud, Rodolfo G.

2009-01-01

A liquid-liquid extraction procedure (L-L) based on room temperature ionic liquid (RTIL) was developed for the preconcentration and determination of mercury in different water samples. The analyte was quantitatively extracted with 1-butyl-3-methylimidazolium hexafluorophosphate ([C 4 mim][PF 6 ]) under the form of Hg-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Hg-5-Br-PADAP) complex. A volume of 500 μl of 9.0 mol L -1 hydrochloric acid was used to back-extract the analyte from the RTIL phase into an aqueous media prior to its analysis by flow injection-cold vapor atomic absorption spectrometry (FI-CV-AAS). A preconcentration factor of 36 was achieved upon preconcentration of 20 mL of sample. The limit of detection (LOD) obtained under the optimal conditions was 2.3 ng L -1 and the relative standard deviation (RSD) for 10 replicates at 1 μg L -1 Hg 2+ was 2.8%, calculated with peaks height. The method was successfully applied to the determination of mercury in river, sea, mineral and tap water samples and a certified reference material (CRM).

Multi-functional magnesium alloys containing interstitial oxygen atoms.

Science.gov (United States)

Kang, H; Choi, H J; Kang, S W; Shin, S E; Choi, G S; Bae, D H

2016-03-15

A new class of magnesium alloys has been developed by dissolving large amounts of oxygen atoms into a magnesium lattice (Mg-O alloys). The oxygen atoms are supplied by decomposing titanium dioxide nanoparticles in a magnesium melt at 720 °C; the titanium is then completely separated out from the magnesium melt after solidification. The dissolved oxygen atoms are located at the octahedral sites of magnesium, which expand the magnesium lattice. These alloys possess ionic and metallic bonding characteristics, providing outstanding mechanical and functional properties. A Mg-O-Al casting alloy made in this fashion shows superior mechanical performance, chemical resistance to corrosion, and thermal conductivity. Furthermore, a similar Mg-O-Zn wrought alloy shows high elongation to failure (>50%) at room temperature, because the alloy plastically deforms with only multiple slips in the sub-micrometer grains (alloys are expected to open a new paradigm in commercial alloy design.

Radiation induced polymerization of MMA in imidazolium ionic liquids and their mixed solutions with organic solvents

Energy Technology Data Exchange (ETDEWEB)

Qi Mingying [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P.O. Box 800-204, Shanghai 201800 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China); Wu Guozhong [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P.O. Box 800-204, Shanghai 201800 (China)], E-mail: wuguozhong@sinap.ac.cn; Sha Maolin; Liu Yusheng [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P.O. Box 800-204, Shanghai 201800 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China)

2008-10-15

Considerably higher molecular weight (M{sub w}) and multi-modal molecular weight distribution (MWD) of poly(methyl methacrylate) (PMMA) were observed in neat ionic liquids ([bmim][PF{sub 6}] and [bmim][BF{sub 4}]), as well as their mixed solutions with organic solvents, probably due to the high viscosity and inhomogeneity of ionic liquids. FTIR spectra for PMMA showed that a slight amount of ionic liquid remained in the resulting polymer, and DSC measurement indicated the increase of glass transition point of PMMA with increasing of ionic liquid fraction in mixed solutions.

Collinear laser spectroscopy of atomic cadmium

CERN Document Server

Frömmgen, Nadja; Bissell, Mark L.; Bieroń, Jacek; Blaum, Klaus; Cheal, Bradley; Flanagan, Kieran; Fritzsche, Stephan; Geppert, Christopher; Hammen, Michael; Kowalska, Magdalena; Kreim, Kim; Krieger, Andreas; Neugart, Rainer; Neyens, Gerda; Rajabali, Mustafa M.; Nörtershäuser, Wilfried; Papuga, Jasna; Yordanov, Deyan T.

2015-01-01

Hyperfine structure $A$ and $B$ factors of the atomic $5s\\,5p\\,\\; ^3\\rm{P}_2 \\rightarrow 5s\\,6s\\,\\; ^3\\rm{S}_1$ transition are determined from collinear laser spectroscopy data of $^{107-123}$Cd and $^{111m-123m}$Cd. Nuclear magnetic moments and electric quadrupole moments are extracted using reference dipole moments and calculated electric field gradients, respectively. The hyperfine structure anomaly for isotopes with $s_{1/2}$ and $d_{5/2}$ nuclear ground states and isomeric $h_{11/2}$ states is evaluated and a linear relationship is observed for all nuclear states except $s_{1/2}$. This corresponds to the Moskowitz-Lombardi rule that was established in the mercury region of the nuclear chart but in the case of cadmium the slope is distinctively smaller than for mercury. In total four atomic and ionic levels were analyzed and all of them exhibit a similar behaviour. The electric field gradient for the atomic $5s\\,5p\\,\\; ^3\\mathrm{P}_2$ level is derived from multi-configuration Dirac-Hartree-Fock calculatio...

Lanthanum(III) and Lutetium(III) in Nitrate-Based Ionic Liquids: A Theoretical Study of Their Coordination Shell.

Science.gov (United States)

Bodo, Enrico

2015-09-03

By using ab initio molecular dynamics, we investigate the solvent shell structure of La(3+) and Lu(3+) ions immersed in two ionic liquids, ethylammonium nitrate (EAN) and its hydroxy derivative (2-ethanolammonium nitrate, HOEAN). We provide the first study of the coordination properties of these heavy metal ions in such a highly charged nonacqueous environment. We find, as expected, that the coordination in the liquid is mainly due to nitrate anions and that, due to the bidentate nature of the ligand, the complexation shell of the central ion has a nontrivial geometry and a coordination number in terms of nitrate molecules that apparently violates the decrease of ionic radii along the lanthanides series, since the smaller Lu(3+) ion seems to coordinate six nitrate molecules and the La(3+) ion only five. A closer inspection of the structural features obtained from our calculations shows, instead, that the first shell of oxygen atoms is more compact for Lu(3+) than for La(3+) and that the former coordinates 8 oxygen atoms while the latter 10 in accord with the typical lanthanide's trend along the series and that their first solvation shells have a slight irregular and complex geometrical pattern. When moving to the HOEAN solutions, we have found that the solvation of the central ion is possibly also due to the cation itself through the oxygen atom on the side chain. Also, in this liquid, the coordination numbers in terms of oxygen atoms in both solvents is 10 for La(3+) and 8 for Lu(3+).

Canopy Dynamics in Nanoscale Ionic Materials

KAUST Repository

Jespersen, Michael L.

2010-07-27

Nanoscale ionic materials (NIMS) are organic - inorganic hybrids in which a core nanostructure is functionalized with a covalently attached corona and an ionically tethered organic canopy. NIMS are engineered to be liquids under ambient conditions in the absence of solvent and are of interest for a variety of applications. We have used nuclear magnetic resonance (NMR) relaxation and pulse-field gradient (PFG) diffusion experiments to measure the canopy dynamics of NIMS prepared from 18-nm silica cores modified by an alkylsilane monolayer possessing terminal sulfonic acid functionality, paired with an amine-terminated ethylene oxide/propylene oxide block copolymer canopy. Carbon NMR studies show that the block copolymer canopy is mobile both in the bulk and in the NIMS and that the fast (ns) dynamics are insensitive to the presence of the silica nanoparticles. Canopy diffusion in the NIMS is slowed relative to the neat canopy, but not to the degree predicted from the diffusion of hard-sphere particles. Canopy diffusion is not restricted to the surface of the nanoparticles and shows unexpected behavior upon addition of excess canopy. Taken together, these data indicate that the liquid-like behavior in NIMS is due to rapid exchange of the block copolymer canopy between the ionically modified nanoparticles. © 2010 American Chemical Society.

Canopy Dynamics in Nanoscale Ionic Materials

KAUST Repository

Jespersen, Michael L.; Mirau, Peter A.; Meerwall, Ernst von; Vaia, Richard A.; Rodriguez, Robert; Giannelis, Emmanuel P.

2010-01-01

Nanoscale ionic materials (NIMS) are organic - inorganic hybrids in which a core nanostructure is functionalized with a covalently attached corona and an ionically tethered organic canopy. NIMS are engineered to be liquids under ambient conditions in the absence of solvent and are of interest for a variety of applications. We have used nuclear magnetic resonance (NMR) relaxation and pulse-field gradient (PFG) diffusion experiments to measure the canopy dynamics of NIMS prepared from 18-nm silica cores modified by an alkylsilane monolayer possessing terminal sulfonic acid functionality, paired with an amine-terminated ethylene oxide/propylene oxide block copolymer canopy. Carbon NMR studies show that the block copolymer canopy is mobile both in the bulk and in the NIMS and that the fast (ns) dynamics are insensitive to the presence of the silica nanoparticles. Canopy diffusion in the NIMS is slowed relative to the neat canopy, but not to the degree predicted from the diffusion of hard-sphere particles. Canopy diffusion is not restricted to the surface of the nanoparticles and shows unexpected behavior upon addition of excess canopy. Taken together, these data indicate that the liquid-like behavior in NIMS is due to rapid exchange of the block copolymer canopy between the ionically modified nanoparticles. © 2010 American Chemical Society.

Self-assembled thin film of imidazolium ionic liquid on a silicon surface: Low friction and remarkable wear-resistivity

International Nuclear Information System (INIS)

Gusain, Rashi; Kokufu, Sho; Bakshi, Paramjeet S.; Utsunomiya, Toru; Ichii, Takashi; Sugimura, Hiroyuki; Khatri, Om P.

2016-01-01

Graphical abstract: - Highlights: • Ionic liquid thin film is deposited on a silicon surface via covalent interaction. • Chemical and morphological features of ionic liquid thin film are probed by XPS and AFM. • Ionic liquid thin film exhibited low and steady friction along with remarkable wear-resistivity. - Abstract: Imidazolium-hexafluorophosphate (ImPF_6) ionic liquid thin film is prepared on a silicon surface using 3-chloropropyltrimethoxysilane as a bifunctional chemical linker. XPS result revealed the covalent grafting of ImPF_6 thin film on a silicon surface. The atomic force microscopic images demonstrated that the ImPF_6 thin film is composed of nanoscopic pads/clusters with height of 3–7 nm. Microtribological properties in terms of coefficient of friction and wear-resistivity are probed at the mean Hertzian contact pressure of 0.35–0.6 GPa under the rotational sliding contact. The ImPF_6 thin film exhibited low and steady coefficient of friction (μ = 0.11) along with remarkable wear-resistivity to protect the underlying silicon substrate. The low shear strength of ImPF_6 thin film, the covalent interaction between ImPF_6 ionic liquid thin film and underlying silicon substrate, and its regular grafting collectively reduced the friction and improved the anti-wear property. The covalently grafted ionic liquid thin film further shows immense potential to expand the durability and lifetime of M/NEMS based devices with significant reduction of the friction.

Self-assembled thin film of imidazolium ionic liquid on a silicon surface: Low friction and remarkable wear-resistivity

Energy Technology Data Exchange (ETDEWEB)

Gusain, Rashi [CSIR-Indian Institute of Petroleum, Mohkampur, Dehardun 248005 (India); Academy of Scientific and Innovative Research, New Delhi 110025 (India); Kokufu, Sho [Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501 (Japan); Bakshi, Paramjeet S. [CSIR-Indian Institute of Petroleum, Mohkampur, Dehardun 248005 (India); Utsunomiya, Toru; Ichii, Takashi; Sugimura, Hiroyuki [Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501 (Japan); Khatri, Om P., E-mail: opkhatri@iip.res.in [CSIR-Indian Institute of Petroleum, Mohkampur, Dehardun 248005 (India); Academy of Scientific and Innovative Research, New Delhi 110025 (India)

2016-02-28

Graphical abstract: - Highlights: • Ionic liquid thin film is deposited on a silicon surface via covalent interaction. • Chemical and morphological features of ionic liquid thin film are probed by XPS and AFM. • Ionic liquid thin film exhibited low and steady friction along with remarkable wear-resistivity. - Abstract: Imidazolium-hexafluorophosphate (ImPF{sub 6}) ionic liquid thin film is prepared on a silicon surface using 3-chloropropyltrimethoxysilane as a bifunctional chemical linker. XPS result revealed the covalent grafting of ImPF{sub 6} thin film on a silicon surface. The atomic force microscopic images demonstrated that the ImPF{sub 6} thin film is composed of nanoscopic pads/clusters with height of 3–7 nm. Microtribological properties in terms of coefficient of friction and wear-resistivity are probed at the mean Hertzian contact pressure of 0.35–0.6 GPa under the rotational sliding contact. The ImPF{sub 6} thin film exhibited low and steady coefficient of friction (μ = 0.11) along with remarkable wear-resistivity to protect the underlying silicon substrate. The low shear strength of ImPF{sub 6} thin film, the covalent interaction between ImPF{sub 6} ionic liquid thin film and underlying silicon substrate, and its regular grafting collectively reduced the friction and improved the anti-wear property. The covalently grafted ionic liquid thin film further shows immense potential to expand the durability and lifetime of M/NEMS based devices with significant reduction of the friction.

Ions-induced nanostructuration: effect of specific ionic adsorption on hydrophobic polymer surfaces.

Science.gov (United States)

Siretanu, Igor; Chapel, Jean-Paul; Bastos-González, Delfi; Drummond, Carlos

2013-06-06

The effect of surface charges on the ionic distribution in close proximity to an interface has been extensively studied. On the contrary, the influence of ions (from dissolved salts) on deformable interfaces has been barely investigated. Ions can adsorb from aqueous solutions on hydrophobic surfaces, generating forces that can induce long-lasting deformation of glassy polymer films, a process called ion-induced polymer nanostructuration, IPN. We have found that this process is ion-specific; larger surface modifications are observed in the presence of water ions and hydrophobic and amphiphilic ions. Surface structuration is also observed in the presence of certain salts of lithium. We have used streaming potential and atomic force microscopy to study the effect of dissolved ions on the surface properties of polystyrene films, finding a good correlation between ionic adsorption and IPN. Our results also suggest that the presence of strongly hydrated lithium promotes the interaction of anions with polystyrene surfaces and more generally with hydrophobic polymer surfaces, triggering then the IPN process.

Semiclassical calculation of ionisation rate for Rydberg helium atoms in an electric field

International Nuclear Information System (INIS)

Wang De-Hua

2011-01-01

The ionisation of Rydberg helium atoms in an electric field above the classical ionisation threshold has been examined using the semiclassical method, with particular emphasis on discussing the influence of the core scattering on the escape dynamics of electrons. The results show that the Rydberg helium atoms ionise by emitting a train of electron pulses. Unlike the case of the ionisation of Rydberg hydrogen atom in parallel electric and magnetic fields, where the pulses of the electron are caused by the external magnetic field, the pulse trains for Rydberg helium atoms are created through core scattering. Each peak in the ionisation rate corresponds to the contribution of one core-scattered combination trajectory. This fact further illustrates that the ionic core scattering leads to the chaotic property of the Rydberg helium atom in external fields. Our studies provide a simple explanation for the escape dynamics in the ionisation of nonhydrogenic atoms in external fields. (atomic and molecular physics)

How ionic strength affects the conformational behavior of human and rat beta amyloids--a computational study.

Directory of Open Access Journals (Sweden)

Zdeněk Kříž

Full Text Available Progressive cerebral deposition of amyloid beta occurs in Alzheimers disease and during the aging of certain mammals (human, monkey, dog, bear, cow, cat but not others (rat, mouse. It is possibly due to different amino acid sequences at positions 5, 10 and 13. To address this issue, we performed series of 100 ns long trajectories (each trajectory was run twice with different initial velocity distribution on amyloid beta (1-42 with the human and rat amino acid sequence in three different environments: water with only counter ions, water with NaCl at a concentration of 0.15 M as a model of intracellular Na(+ concentration at steady state, and water with NaCl at a concentration of 0.30 M as a model of intracellular Na(+ concentration under stimulated conditions. We analyzed secondary structure stability, internal hydrogen bonds, and residual fluctuation. It was observed that the change in ionic strength affects the stability of internal hydrogen bonds. Increasing the ionic strength increases atomic fluctuation in the hydrophobic core of the human amyloid, and decreases the atomic fluctuation in the case of rat amyloid. The secondary structure analyses show a stable α-helix part between residues 10 and 20. However, C-terminus of investigated amyloids is much more flexible showing no stable secondary structure elements. Increasing ionic strength of the solvent leads to decreasing stability of the secondary structural elements. The difference in conformational behavior of the three amino acids at position 5, 10 and 13 for human and rat amyloids significantly changes the conformational behavior of the whole peptide.

Effect of ionic strength on the kinetics of ionic and micellar reactions in aqueous solution

International Nuclear Information System (INIS)

Dung, M.H.; Kozak, J.J.

1982-01-01

The effect of electrostatic forces on the rate of reaction between ions in aqueous solutions of intermediate ionic strength is studied in this paper. We consider the kinetics of reactions involving simple ionic species (1--1 and 2--2 electrolyte systems) as well as kinetic processes mediated by the presence of micellar ions (or other charged organizates). In the regime of ionic strength considered, dielectric saturation of the solvent in the vicinity of the reacting ions must be taken into account and this is done by introducing several models to describe the recovery of the solvent from saturation to its continuum dielectric behavior. To explore the effects of ion size, charge number, and ionic strength on the overall rate constant for the process considered, we couple the traditional theory of ionic reactions in aqueous solution with calculations of the electrostatic potential obtained via solution of the nonlinear Poisson--Boltzmann equation. The great flexibility of the nonlinear Poisson--Boltzmann theory allows us to explore quantitatively the influence of each of these effects, and our simulations show that the short-range properties of the electrostatic potential affect primarily kinetically controlled processes (to varying degrees, depending on the ionic system considered) whereas the down-range properties of the potential play a (somewhat) greater role in influencing diffusion-controlled processes. A detailed examination is made of ionic strength effects over a broad range of ionic concentrations. In the regime of low ionic strength, the limiting slope and intercept of the curve describing the dependence of log k/sub D/ on I/sup 1/2//(1+I/sup 1/2/) may differ considerably from the usual Debye--Hueckel limiting relations, depending on the particular model chosen to describe local saturation effects

Comparative Investigation of the Ionicity of Aprotic and Protic Ionic Liquids in Molecular Solvents by using Conductometry and NMR Spectroscopy.

Science.gov (United States)

Thawarkar, Sachin; Khupse, Nageshwar D; Kumar, Anil

2016-04-04

Electrical conductivity (σ), viscosity (η), and self-diffusion coefficient (D) measurements of binary mixtures of aprotic and protic imidazolium-based ionic liquids with water, dimethyl sulfoxide, and ethylene glycol were measured from 293.15 to 323.15 K. The temperature dependence study reveals typical Arrhenius behavior. The ionicities of aprotic ionic liquids were observed to be higher than those of protic ionic liquids in these solvents. The aprotic ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate, [bmIm][BF4 ], displays 100 % ionicity in both water and ethylene glycol. The protic ionic liquids in both water and ethylene glycol are classed as good ionic candidates, whereas in DMSO they are classed as having a poor ionic nature. The solvation dynamics of the ionic species of the ionic liquids are illustrated on the basis of the (1) H NMR chemical shifts of the ionic liquids. The self-diffusion coefficients D of the cation and anion of [HmIm][CH3 COO] in D2 O and in [D6 ]DMSO are determined by using (1) H nuclei with pulsed field gradient spin-echo NMR spectroscopy. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Structure, ionic conductivity and mobile carrier density in fast ionic conducting chalcogenide glasses

Energy Technology Data Exchange (ETDEWEB)

Yao, Wenlong [Iowa State Univ., Ames, IA (United States)

2006-01-01

This thesis consists of six sections. The first section gives the basic research background on the ionic conduction mechanism in glass, polarization in the glass, and the method of determining the mobile carrier density in glass. The proposed work is also included in this section. The second section is a paper that characterizes the structure of MI + M₂S + (0.1 Ga₂S₃ + 0.9 GeS₂) (M = Li, Na, K and Cs) glasses using Raman and IR spectroscopy. Since the ionic radius plays an important role in determining the ionic conductivity in glasses, the glass forming range for the addition of different alkalis into the basic glass forming system 0.1 Ga₂S₃ + 0.9 GeS₂ was studied. The study found that the change of the alkali radius for the same nominal composition causes significant structure change to the glasses. The third section is a paper that investigates the ionic conductivity of MI + M₂S + (0.1Ga₂S₃ + 0.9 GeS₂) (M = Li, Na, K and Cs) glasses system. Corresponding to the compositional changes in these fast ionic conducting glasses, the ionic conductivity shows changes due to the induced structural changes. The ionic radius effect on the ionic conductivity in these glasses was investigated. The fourth section is a paper that examines the mobile carrier density based upon the measurements of space charge polarization. For the first time, the charge carrier number density in fast ionic conducting chalcogenide glasses was determined. The experimental impedance data were fitted using equivalent circuits and the obtained parameters were used to determine the mobile carrier density. The influence of mobile carrier density and mobility on the ionic conductivity was separated. The fifth section is a paper that studies the structures of low-alkali-content Na₂S + B₂S₃ (x ≤ 0.2) glasses by neutron and synchrotron x-ray diffraction

An experimental observation of the different behavior of ionic and neutral lines of iron as a function of number density in a binary carbon–iron mixture

International Nuclear Information System (INIS)

Sivakumar, P.; Taleh, L.; Markushin, Y.; Melikechi, N.; Lasue, J.

2013-01-01

We report on the dependence of the intensities of atomic and ionic lines emitted by a nanosecond laser-induced plasma on the atomic number densities of the constituents of a binary mixture formed of carbon and iron. We show that the packing density of the sample greatly affects the relative standard deviation of the emission lines. Furthermore, we show that the variation of the intensities of the C and Fe emission lines depends in a non-trivial way on the relative C–Fe concentration. The intensities of Fe neutral atomic lines behave differently than those of the ionic ones particularly at and above concentrations of 75%–80% Fe embedded in a carbon matrix. Unlike the emission from neutral Fe, those from ionic Fe yield a very sharp decrease followed by an equally strong increase of the emission lines over a relatively small range of relative concentration of C and Fe. To better investigate this effect, we have compared the results obtained with nanosecond-LIBS to those with femtosecond-LIBS and found that this phenomenon disappears. The physical interpretation of the sharp decrease followed by an equally sharp increase in the emission intensities from Fe ions as the concentration of Fe is increased requires more studies. - Highlights: ► The effects of the size of the particles on the fluctuations of the LIBS signals ► The variation of LIBS signals with the concentrations of Fe embedded in C is nontrivial. ► The intensities of neutral atomic lines can behave differently than those of ions

Electronic excitation and ionic dissociation of the vanillin molecule: photoionization with flavor

International Nuclear Information System (INIS)

Betancourt, A Moreno; De Souza, G G B; Bernini, R B; Coutinho, L H

2015-01-01

The electronic properties of vanillin molecule were investigated by different excitation and ionization techniques. The Ionic fragmentation mechanisms were studied using time-of-flight mass spectrometry as a function of the energy of the incident radiation in the valence energy region and the inner and core levels. It was stablished as a general feature that the ruptures related to the oxygen atoms are predominant at all energies. The resonances and ionization potential of the oxygen 1s was also determined by NEXAFS spectra. (paper)

LID: Computer code for identifying atomic and ionic lines below 3500 Angstroms

International Nuclear Information System (INIS)

Peek, J.M.; Dukart, R.J.

1987-08-01

An interactive computer code has been written to search a data base containing information useful for identifying lines in experimentally-observed spectra or for designing experiments. The data base was the basis for the Kelly and Palumbo critical review of well-resolved lines below 2000 Angstroms, includes lines below 3500 Angstroms for atoms and ions of hydrogen through krypton, and was obtained from R.L. Kelly. This code allows the user to search the data base for a user-specified wavelength region, with this search either limited to atoms or ions of the user's choice for all atoms and ions contained in the data base. The line information found in the search is stored in a local file for later reference. A plotting capability is provided to graphically display the lines resulting from the search. Several options are available to control the nature of these graphs. It is also possible to bring in data from another source, such as an experimental spectra, for display along with the lines from the data-base search. Options for manipulating the experimental spectra's background intensity and wavelength scale are also available to the user. The intensities for the lines from each ion found in the data-base search can be scaled by a multiplicative constant to better simulate the observed spectrum

Cathodoluminescence of GaN diped with Zn in the process of epitaxial growth and by the method of ionic implantation

International Nuclear Information System (INIS)

Khasanov, I.Sh.; Gippius, A.A.; Kuznetsov, A.V.; Petrov, M.N.; Sletov, M.M.

1984-01-01

The cathodoluminescence (CL) method was used to investigate the epitaxial GaN layers doped with Zn both in the process of growth and by the method of ionic implantation for the purpose of clarifying the effect of doping technique on impurity luminescence. It was shown that (2-3)x10 18 cm -3 concentration is optimal with respect to intensity of impurity ''blue'' luminescence for gallium nitride doped with Zn. The intensity of GaN ''blue'' luminescence during Zn ionic implantation is several times lower as compared with doping in the process of growth. This is related to incomplete optical activation of impurity atoms in the process of postimplantation thermal annealing. Increase of zinc concentration above optimal during ionic implantation intensifies crystal lattice disordering, which is supported by intensification of 1.7 eV cathodoluminescence band in spectra conditioned by defects

A numerical study on charging mechanism in leaky dielectric liquids inside the electrostatic atomizers

Science.gov (United States)

Kashir, Babak; Perri, Anthony; Yarin, Alexander L.; Mashayek, Farzad

2017-11-01

The charging of leaky dielectric liquids inside an electrostatic atomizer is studied numerically by developed codes based on OpenFOAM platform. Faradaic reactions are taken into account as the electrification mechanism. The impact of ionic finite size (steric terms) in high voltages is also investigated. The fundamental electrohydrodynamic understanding of the charging mechanism is aimed in the present work where the creation of polarized near-electrode layer and the movement of charges due to hydrodynamic flow are studied in conjunction with the solution of the Navier-Stokes equations. The case of a micro channel electrohydrodynamic flow subjected to two electrodes of the opposite polarity is considered as an example, with the goal to predict the resulting net charge at the exit. Even though the electrodes constitute a small portion of the channel wall, otherwise insulated, it is indicated that the channel length plays a dominant role in the discharging net charge. The ionic fluxes at the electrode surfaces are accounted through the Frumkin-Butler-Volmer relation found from the concurrent in-house experimental investigations. This projects was supported by National science Foundation (NSF) GOALI Grant CBET-1505276.

Ionic Liquids in Tribology

Directory of Open Access Journals (Sweden)

Ichiro Minami

2009-06-01

Full Text Available Current research on room-temperature ionic liquids as lubricants is described. Ionic liquids possess excellent properties such as non-volatility, non-flammability, and thermo-oxidative stability. The potential use of ionic liquids as lubricants was first proposed in 2001 and approximately 70 articles pertaining to fundamental research on ionic liquids have been published through May 2009. A large majority of the cations examined in this area are derived from 1,3-dialkylimidazolium, with a higher alkyl group on the imidazolium cation being beneficial for good lubrication, while it reduces the thermo-oxidative stability. Hydrophobic anions provide both good lubricity and significant thermo-oxidative stability. The anions decompose through a tribochemical reaction to generate metal fluoride on the rubbed surface. Additive technology to improve lubricity is also explained. An introduction to tribology as an interdisciplinary field of lubrication is also provided.

Ionic liquids in tribology.

Science.gov (United States)

Minami, Ichiro

2009-06-24

Current research on room-temperature ionic liquids as lubricants is described. Ionic liquids possess excellent properties such as non-volatility, non-flammability, and thermo-oxidative stability. The potential use of ionic liquids as lubricants was first proposed in 2001 and approximately 70 articles pertaining to fundamental research on ionic liquids have been published through May 2009. A large majority of the cations examined in this area are derived from 1,3-dialkylimidazolium, with a higher alkyl group on the imidazolium cation being beneficial for good lubrication, while it reduces the thermo-oxidative stability. Hydrophobic anions provide both good lubricity and significant thermo-oxidative stability. The anions decompose through a tribochemical reaction to generate metal fluoride on the rubbed surface. Additive technology to improve lubricity is also explained. An introduction to tribology as an interdisciplinary field of lubrication is also provided.

Inter-atomic force constants of BaF{sub 2} by diffuse neutron scattering measurement

Energy Technology Data Exchange (ETDEWEB)

Sakuma, Takashi, E-mail: sakuma@mx.ibaraki.ac.jp; Makhsun,; Sakai, Ryutaro [Institute of Applied Beam Science, Ibaraki University, Mito 310-8512 (Japan); Xianglian [College of Physics and Electronics Information, Inner Mongolia University for the Nationalities, Tongliao 028043 (China); Takahashi, Haruyuki [Institute of Applied Beam Science, Ibaraki University, Hitachi 316-8511 (Japan); Basar, Khairul [Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Bandung 40132 (Indonesia); Igawa, Naoki [Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai 319-1195 (Japan); Danilkin, Sergey A. [Bragg Institute, Australian Nuclear Science and Technology Organisation, Kirrawee DC NSW 2232 (Australia)

2015-04-16

Diffuse neutron scattering measurement on BaF{sub 2} crystals was performed at 10 K and 295 K. Oscillatory form in the diffuse scattering intensity of BaF{sub 2} was observed at 295 K. The correlation effects among thermal displacements of F-F atoms were obtained from the analysis of oscillatory diffuse scattering intensity. The force constants among neighboring atoms in BaF{sub 2} were determined and compared to those in ionic crystals and semiconductors.

Mutagenic effects induced by accumulating rare earths nuclides with different ionic radius in fission fragments

International Nuclear Information System (INIS)

Zhu Shoupeng; Wang Liuyi; Cao Genfa; Sun Baofu

1991-05-01

The purpose of the present study was to ascertain the correlation between the different ionic radius of rare earths nuclides such as 170 Tm, 152 Eu, 147 Pm and its accumulation peculiarity as well as induction of mutagenic effect on bone marrow cells. The study showed that the accumulation peculiarity of rare earths nuclides will vary with the ionic radius. The results indicated that large ionic radius of 147 Pm was selectively localized in liver in early stage, while small ionic radius of 170 Tm and 152 Eu were deposited in bone predominantly. There was a positive relationship between the incidence of chromosome aberration rates and the absorption dose in skeleton by 170 Tm, 152 Eu, or 147 Pm. Studies indicated that the chromosome aberration rates were elevated when the absorption dose in skeleton was increased. Among the type of chromosome aberrations induced by rare earths nuclides with different ionic radius, chromatid breakage was predominant, accompanied with a few chromosome breakage and translocation. At the same time mitosis index of metaphase cells was depressed. Internal contamination of 170 Tm, 152 Eu, or 147 Pm can be induced by some aberrations in one cell. This phenomenon might be due in part to nonuniform irradiation of bone marrow cell with local deposition of these rare earths nuclides with different ionic radius

Full characterization of polypyrrole thin films electrosynthesized in room temperature ionic liquids, water or acetonitrile

International Nuclear Information System (INIS)

Viau, L.; Hihn, J.Y.; Lakard, S.; Moutarlier, V.; Flaud, V.; Lakard, B.

2014-01-01

Highlights: • Polypyrrole films were electrodeposited from three room temperature ionic liquids. • Polymer films were characterized using many surface analysis techniques. • The incorporation of anions and/or cations inside the polymer films was evidenced. • The influence of the ionic liquid on the polymer properties was deeply studied. - Abstract: Pyrrole was electrochemically oxidized in two conventional media (water and acetonitrile) and in three room temperature ionic liquids: 1-butyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, and 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide. Infrared and Raman Spectroscopies confirmed the formation of polypyrrole by electropolymerization but were unable to demonstrate the presence of anions in the polymer films. The use of ionic liquids as growth media resulted in polymer films having a good electrochemical activity. The difference of activity from one polymer film to the other was mainly attributed to the difference of viscosity between the solvents used. The morphological features of the polypyrrole films were also fully studied. Profilometric measurements demonstrated that polymer films grown, at the same potential, in ionic liquids were thinner and had a smaller roughness than those grown in other solvents. Atomic Force Microscopy showed that polypyrrole films had nearly similar micrometric nodular structure whatever the growth medium even if some differences of porosity and homogeneity were observed using Scanning Electron Microscopy. The incorporation of counter-anions at the top surface of the films was finally evidenced by X-ray Photoelectron Spectroscopy. These anions were also incorporated inside the polymer film with a uniform distribution as shown by Glow Discharge Optical Emission Spectroscopy

Alkaline ionic liquids applied in supported ionic liquid catalyst for selective hydrogenation of citral to citronellal

Directory of Open Access Journals (Sweden)

Eero eSalminen

2014-02-01

Full Text Available The challenge in preparation of ionic liquids containing a strong alkaline anion is to identify a suitable cation which can tolerate the harsh conditions induced by the anion. In this study, a commercial quaternary ammonium compound (quat benzalkonium [ADBA] (alkyldimethylbenzylammonium was used as a cation in the synthesis of different alkaline ionic liquids. In fact, the precursor, benzalkonium chloride, is a mixture of alkyldimethylbenzylammonium chlorides of various alkyl chain lengths and is commonly used in the formulation of various antiseptic products. The prepared ionic liquids were utilized as Supported Ionic Liquid Catalysts (SILCAs. Typically, a SILCA contains metal nanoparticles, enzymes or metal complexes in an ionic liquid layer which is immobilized on a solid carrier material such as an active carbon cloth (ACC. The catalysts were applied in the selective hydrogenation of citral to citronellal which is an important perfumery chemical. Interestingly, 70 % molar yield towards citronellal was achieved over a catalyst containing the alkaline ionic liquid benzalkonium methoxide.

Alkaline ionic liquids applied in supported ionic liquid catalyst for selective hydrogenation of citral to citronellal

Science.gov (United States)

Salminen, Eero; Virtanen, Pasi; Mikkola, Jyri-Pekka

2014-01-01

The challenge in preparation of ionic liquids containing a strong alkaline anion is to identify a suitable cation which can tolerate the harsh conditions induced by the anion. In this study, a commercial quaternary ammonium compound (quat) benzalkonium [ADBA] (alkyldimethylbenzylammonium) was used as a cation in the synthesis of different alkaline ionic liquids. In fact, the precursor, benzalkonium chloride, is a mixture of alkyldimethylbenzylammonium chlorides of various alkyl chain lengths and is commonly used in the formulation of various antiseptic products. The prepared ionic liquids were utilized as Supported Ionic Liquid Catalysts (SILCAs). Typically, a SILCA contains metal nanoparticles, enzymes, or metal complexes in an ionic liquid layer which is immobilized on a solid carrier material such as an active carbon cloth (ACC). The catalysts were applied in the selective hydrogenation of citral to citronellal which is an important perfumery chemical. Interestingly, 70% molar yield toward citronellal was achieved over a catalyst containing the alkaline ionic liquid benzalkonium methoxide. PMID:24790972

Application of Ionic Liquids in Hydrometallurgy

Science.gov (United States)

Park, Jesik; Jung, Yeojin; Kusumah, Priyandi; Lee, Jinyoung; Kwon, Kyungjung; Lee, Churl Kyoung

2014-01-01

Ionic liquids, low temperature molten salts, have various advantages manifesting themselves as durable and environmentally friendly solvents. Their application is expanding into various fields including hydrometallurgy due to their unique properties such as non-volatility, inflammability, low toxicity, good ionic conductivity, and wide electrochemical potential window. This paper reviews previous literatures and our recent results adopting ionic liquids in extraction, synthesis and processing of metals with an emphasis on the electrolysis of active/light, rare earth, and platinum group metals. Because the research and development of ionic liquids in this area are still emerging, various, more fundamental approaches are expected to popularize ionic liquids in the metal manufacturing industry. PMID:25177864

Kinetics of hydrogen release from dissolutions of ammonia borane in different ionic liquids

International Nuclear Information System (INIS)

Valero-Pedraza, María José; Martín-Cortés, Alexandra; Navarrete, Alexander; Bermejo, María Dolores; Martín, Ángel

2015-01-01

Ammonia borane is a promising hydrogen storage material that liberates hydrogen by thermolysis at moderate temperatures, but it also presents major limitations for practical applications including a long induction time before the initiation of hydrogen release and a difficult regeneration. Previous works have demonstrated that by dissolution of ammonia borane into several ionic liquids, and particularly in 1-butyl-3-methylimidazolium chloride bmimCl, the induction period at the beginning of the thermolysis is eliminated, but some problems persist, including foaming and the formation of a residue after thermolysis that is insoluble in the ionic liquid. In this work, the release of hydrogen from ammonia borane dissolved in different ionic liquids has been analyzed, measuring the kinetics of hydrogen release, visually following the evolution of the sample during the process using pressure glass tube reactors, and analyzing the residue by spectroscopic techniques. While dissolutions of ammonia borane in most ionic liquids analyzed show similar properties as dissolutions in bmimCl, using ionic liquids with bis(trifluoromethylsulfanyl)imide Tf_2N anion the foaming problem is reduced, and in some cases the residue remains dissolved in the ionic liquid, while with ionic liquids with choline anion higher hydrogen yields are achieved that indicate that the decomposition of ammonia borane proceeds through a different path. - Highlights: • Hydrogen release from ammonia borane dissolved in 13 ionic liquids has been studied. • Induction time is shortened and hydrogen release rate is accelerated in all cases. • The best results are obtained using ionic liquids with Tf_2N anion. • Ch cation ionic liquids enable higher H_2 yield, but cyclotriborazane is produced.

Radiation Chemistry and Photochemistry of Ionic Liquids

International Nuclear Information System (INIS)

Wishart, J.F.; Takahaski, K.

2010-01-01

As our understanding of ionic liquids and their tunable properties has grown, it is possible to see many opportunities for ionic liquids to contribute to the sustainable use of energy. The potential safety and environmental benefits of ionic liquids, as compared to conventional solvents, have attracted interest in their use as processing media for the nuclear fuel cycle. Therefore, an understanding of the interactions of ionizing radiation and photons with ionic liquids is strongly needed. However, the radiation chemistry of ionic liquids is still a relatively unexplored topic although there has been a significant increase in the number of researchers in the field recently. This article provides a brief introduction to ionic liquids and their interesting properties, and recent advances in the radiation chemistry and photochemistry of ionic liquids. In this article, we will mainly focus on excess electron dynamics and radical reaction dynamics. Because solvation dynamics processes in ionic liquids are much slower than in molecular solvents, one of the distinguishing characteristics is that pre-solvated electrons play an important role in ionic liquid radiolysis. It will be also shown that the reaction dynamics of radical ions is significantly different from that observed in molecular solvents because of the Coulombic screening effects and electrostatic interactions in ionic liquids.

Ruthenium dioxide nanoparticles in ionic liquids: synthesis, characterization and catalytic properties in hydrogenation of olefins and arenes

International Nuclear Information System (INIS)

Rossi, Liane M.; Dupont, Jairton; Machado, Giovanna; Fichtner, Paulo F.P.; Radtke, Claudio; Baumvol, Israel J.R.; Teixeira, Sergio R.

2004-01-01

The reaction of NaBH 4 with RuCl 3 dissolved in 1-n-butyl-3-methylimidazolium hexafluorophosphate (BMI.PF 6 ) ionic liquid is a simple and reproducible method for the synthesis of stable RuO 2 nanoparticles with a narrow size distribution within 2-3 nm. RuO 2 nanoparticles were characterized by XRD, XPS, EDS and TEM. These nanoparticles showed high catalytic activity either in the solventless or liquid-liquid biphasic hydrogenation of olefins and arenes under mild reaction conditions. Hg(0) and CS 2 poisoning experiments and XRD and TEM analysis of particles isolated after catalysis indicated the formation of Ru(0) nanoparticles. The nanoparticles could be re-used in solventless conditions up to 10 times in the hydrogenation of 1-hexene yielding a total turnover number for exposed Ru atoms of 175,000. (author)

Ionic thermocurrents and ionic conductivity of solid solutions of SrF2 and YbF3

NARCIS (Netherlands)

Meuldijk, J.; Hartog, den H.W.

1983-01-01

We report dielectric [ionic thermocurrent (!TC)] experiments and ionic conductivity of cubic solid solutions of the type Sr1-xYbxF2+x. These combined experiments provide us with new information concerning the ionic conductivity mechanisms which play an important role in solid solutions Sr1-xRxF2+x

Application of Ionic Liquids in Hydrometallurgy

Directory of Open Access Journals (Sweden)

Jesik Park

2014-08-01

Full Text Available Ionic liquids, low temperature molten salts, have various advantages manifesting themselves as durable and environmentally friendly solvents. Their application is expanding into various fields including hydrometallurgy due to their unique properties such as non-volatility, inflammability, low toxicity, good ionic conductivity, and wide electrochemical potential window. This paper reviews previous literatures and our recent results adopting ionic liquids in extraction, synthesis and processing of metals with an emphasis on the electrolysis of active/light, rare earth, and platinum group metals. Because the research and development of ionic liquids in this area are still emerging, various, more fundamental approaches are expected to popularize ionic liquids in the metal manufacturing industry.

Ionic Liquid Crystals: Versatile Materials.

Science.gov (United States)

Goossens, Karel; Lava, Kathleen; Bielawski, Christopher W; Binnemans, Koen

2016-04-27

This Review covers the recent developments (2005-2015) in the design, synthesis, characterization, and application of thermotropic ionic liquid crystals. It was designed to give a comprehensive overview of the "state-of-the-art" in the field. The discussion is focused on low molar mass and dendrimeric thermotropic ionic mesogens, as well as selected metal-containing compounds (metallomesogens), but some references to polymeric and/or lyotropic ionic liquid crystals and particularly to ionic liquids will also be provided. Although zwitterionic and mesoionic mesogens are also treated to some extent, emphasis will be directed toward liquid-crystalline materials consisting of organic cations and organic/inorganic anions that are not covalently bound but interact via electrostatic and other noncovalent interactions.

Fission-Product Separation Based on Room-Temperature Ionic-Liquids

International Nuclear Information System (INIS)

Hussey, Charles L.

2005-01-01

During the previous funding cycle for this project, we investigated the electrochemistry of Cs(I) in air and moisture-stable ionic liquids both with and without the addition of BOBCalixC6. These investigations revealed that the electrochemical windows of the dialkylimidazolium bis[(trifluoromethyl)sulfonyl]imide ionic liquids do not permit the direct electrochemical reduction of Cs(I), even when Hg electrodes are employed, because these organic cations are reduced at less negative potentials than Cs(I). However, Cs(I) coordinated by BOBCalixC6 can be electrolytically reduced to Cs(Hg) in tetraalkylammonium-based room-temperature ionic liquids such as tri-1-butylmethylammonium bis[(trifluoromethyl)sulfonyl]imide (Bu3MeN+Tf2N-) at Hg electrodes. Because this reduction process does not harm either the ionic liquid or the macrocycle, it is a promising method for recycling the cesium extraction system. The previous studies mentioned above were carried out under an inert atmosphere, i.e., in the absence of H2O and O2. However, it may not be economically feasible or even possible to carry out the recycling process in the absence of these contaminants during large-scale processing of aqueous tank waste. Thus, as described in our proposal, we have begun an investigation of the electrochemical recovery of Cs from the Bu3MeN+Tf2N- + BOBCalixC6 extraction system in an air atmosphere containing various amounts of water and oxygen. Our recent preliminary results were very surprising because they indicated that the electrochemical extraction process is relatively insensitive to the presence of small amounts of moisture even when the moisture content of the ionic liquid approaches 1000 ppm. Furthermore, we have found that the ''wet'' ionic liquid can be easily dehydrated under reduced pressure or by sparging with dry nitrogen gas without the need for heat or any other specialized treatment

Ionically cross-linked poly(allylamine) as a stimulus-responsive underwater adhesive: ionic strength and pH effects.

Science.gov (United States)

Lawrence, Patrick G; Lapitsky, Yakov

2015-02-03

Gel-like coacervates that adhere to both hydrophilic and hydrophobic substrates under water have recently been prepared by ionically cross-linking poly(allylamine) (PAH) with pyrophosphate (PPi) and tripolyphosphate (TPP). Among the many advantages of these underwater adhesives (which include their simple preparation and low cost) is their ability to dissolve on demand when exposed to high or low pH. To further analyze their stimulus-responsive properties, we have investigated the pH and ionic strength effects on the formation, rheology and adhesion of PAH/PPi and PAH/TPP complexes. The ionic cross-linker concentrations needed to form these adhesives decreased with increasing pH and ionic strength (although the complexes ceased to form when the parent solution pH exceeded ca. 8.5; i.e., the effective pKa of PAH). Once formed, their ionic cross-links were most stable (as inferred from their relaxation times) at near-neutral or slightly alkaline pH values (of roughly 6.5-9) and at low ionic strengths. The decrease in ionic cross-link stability within complexes prepared at other pH values and at elevated (150-300 mM) NaCl concentrations diminished both the strength and longevity of adhesion (although, under most conditions tested, the short-term tensile adhesion strengths remained above 10(5) Pa). Additionally, the sensitivity of PAH/PPi and PAH/TPP complexes to ionic strength was demonstrated as a potential route to injectable adhesive design (where spontaneous adhesive formation was triggered via injection of low-viscosity, colloidal PAH/TPP dispersions into phosphate buffered saline). Thus, while the sensitivity of ionically cross-linked PAH networks to pH and ionic strength can weaken their adhesion, it can also impart them with additional functionality, such as minimally invasive, injectable delivery, and ability to form and dissolve their bonds on demand.

Ionic liquids influence on the surface properties of electron beam irradiated wood

Energy Technology Data Exchange (ETDEWEB)

Croitoru, Catalin [“Transilvania” University of Brasov, Product Design and Environment Department, 29 Eroilor Str., 500036, Brasov (Romania); Patachia, Silvia, E-mail: st.patachia@unitbv.ro [“Transilvania” University of Brasov, Product Design and Environment Department, 29 Eroilor Str., 500036, Brasov (Romania); Doroftei, Florica; Parparita, Elena; Vasile, Cornelia [“Petru Poni” Institute of Macromolecular Chemistry, Physical Chemistry of Polymers Department, 41A Gr. Ghica Voda Alley, Iasi (Romania)

2014-09-30

Highlights: • Wood veneers impregnated with three imidazolium-based ionic liquids and irradiated with electron beam were studied by FTIR-ATR, SEM/EDX, AFM, contact angle and image analysis. • ILs preserve the surface properties of the wood (surface energy, roughness, color) upon irradiation, in comparison with the reference wood, but the surface composition is changed by treatment with IL-s, mainly with 1-butyl-3-methylimidazolium tetrafluoroborate. • Under electron beam irradiation covalent bonding of the imidazolium moiety to wood determines a higher resistance to water penetration and spreading on the surface. - Abstract: In this paper, the influence of three imidazolium-based ionic liquids (1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate and 1-hexyl-3-methylimidazolium chloride) on the structure and surface properties of sycamore maple (Acer pseudoplatanus) veneers submitted to electron beam irradiation with a dose of 50 kGy has been studied by using Fourier transform infrared spectroscopy, as well as image, scanning electron microscopy/SEM/EDX, atomic force microscopy and contact angle analysis. The experimental results have proven that the studied ionic liquids determine a better preservation of the structural features of wood (cellulose crystallinity index and lignin concentration on the surface) as well as some of surface properties such as surface energy, roughness, color upon irradiation with electron beam, in comparison with the reference wood, but surface composition is changed by treatment with imidazolium-based ionic liquids mainly with 1-butyl-3-methylimidazolium tetrafluoroborate. Also, under electron beam irradiation covalent bonding of the imidazolium moiety to wood determines a higher resistance to water penetration and spreading on the surface.

Ionic liquid – Assisted emulsion polymerization of aniline in organic medium

Energy Technology Data Exchange (ETDEWEB)

Calheiros, Loan F. [Universidade Federal do Rio de Janeiro, Instituto de Macromoléculas, 21941-598, Rio de Janeiro (Brazil); Soares, Bluma G., E-mail: bluma@metalmat.ufrj.br [Universidade Federal do Rio de Janeiro, PEMM-COPPE, Centro de Tecnologia, 21941-972, Rio de Janeiro (Brazil); Universidade Federal do Rio de Janeiro, Instituto de Macromoléculas, 21941-598, Rio de Janeiro (Brazil); Barra, Guilherme M.O. [Universidade Federal de Santa Catarina, Mechanical Engineering Department, Florianópolis, SC (Brazil); Livi, Sébastien [Université de Lyon, F-69003, Lyon (France); INSA Lyon, F-69621, Villeurbanne (France); CNRS, UMR 5223, Ingénierie des Matériaux Polymères (France)

2016-08-15

Polyaniline doped with dodecylbenzene sulfonic acid (PAni.DBSA) with different conductivities and morphologies was prepared by inverted emulsion polymerization, in toluene using ammonium peroxydisulfate as the oxidizing agent, in the presence of two different imidazolium – based ionic liquids, such as, 1-methyl-3-butyl imidazolium tetrafluorate (bmim.BF{sub 4}) and 1-(11-carboxyundecyl)-3-methylimidazolium bromide (mimC{sub 10}COOH.Br). The influence of ionic liquid on the morphology and particle size of formed PAni.DBSA samples was investigated by field emission - scanning electron microscopy (FEG-SEM) and dynamic light scattering (DLS) measurements. Ultraviolet–visible measurements were also employed to confirm the structure of the conducting polymer. PAni.DBSA samples were also characterized by thermogravimetric analysis, cyclic voltammetry and X-ray photoelectron spectroscopy (XPS). PAni.DBSA samples prepared in the presence of ionic liquids have shown improved dispersability in epoxy resin as indicated by optical micrograph. - Highlights: • Imidazolium-based ionic liquids as soft templates for polyaniline synthesis. • PAni with higher conductivity and different morphologies was achieved in the presence of IL. • Good IL/aniline salt interaction resulted in confinement inside PAni particles. • IL confinement confirmed by TGA and XPS analyses. • Excellent dispersability of PAni. DBSA prepared with ionic liquids, in epoxy matrix.

Ionic Conductivity of Polyelectrolyte Hydrogels.

Science.gov (United States)

Lee, Chen-Jung; Wu, Haiyan; Hu, Yang; Young, Megan; Wang, Huifeng; Lynch, Dylan; Xu, Fujian; Cong, Hongbo; Cheng, Gang

2018-02-14

Polyelectrolytes have many important functions in both living organisms and man-made applications. One key property of polyelectrolytes is the ionic conductivity due to their porous networks that allow the transport of water and small molecular solutes. Among polyelectrolytes, zwitterionic polymers have attracted huge attention for applications that involve ion transport in a polyelectrolyte matrix; however, it is still unclear how the functional groups of zwitterionic polymer side chains affect their ion transport and swelling properties. In this study, zwitterionic poly(carboxybetaine acrylamide), poly(2-methacryloyloxyethyl phosphorylcholine), and poly(sulfobetaine methacrylate) hydrogels were synthesized and their ionic conductivity was studied and compared to cationic, anionic, and nonionic hydrogels. The change of the ionic conductivity of zwitterionic and nonionic hydrogels in different saline solutions was investigated in detail. Zwitterionic hydrogels showed much higher ionic conductivity than that of the widely used nonionic poly(ethylene glycol) methyl ether methacrylate hydrogel in all tested solutions. For both cationic and anionic hydrogels, the presence of mobile counterions led to high ionic conductivity in low salt solutions; however, the ionic conductivity of zwitterionic hydrogels surpassed that of cationic and ionic hydrogels in high salt solutions. Cationic and anionic hydrogels showed much higher water content than that of zwitterionic hydrogels in deionized water; however, the cationic hydrogels shrank significantly with increasing saline concentration. This work provides insight into the effects of polyelectrolyte side chains on ion transport. This can guide us in choosing better polyelectrolytes for a broad spectrum of applications, including bioelectronics, neural implants, battery, and so on.

Supported Ionic Liquid Phase (SILP) catalysis

DEFF Research Database (Denmark)

Riisager, Anders; Fehrmann, Rasmus; Haumann, Marco

2006-01-01

Applications of ionic liquids to replace conventional solvents in homogeneous transition-metal catalysis have increased significantly during the last decade. Biphasic ionic liquid/organic liquid systems offer advantages with regard to product separation, catalyst stability, and recycling...... but utilise in the case of fast chemical reactions only a small amount of expensive ionic liquid and catalyst. The novel Supported Ionic Liquid Phase (SILP) catalysis concept overcomes these drawbacks and allows the use of fixed-bed reactors for continuous reactions. In this Microreview the SILP catalysis...

On the Chemical Stabilities of Ionic Liquids

Directory of Open Access Journals (Sweden)

Yen-Ho Chu

2009-09-01

Full Text Available Ionic liquids are novel solvents of interest as greener alternatives to conventional organic solvents aimed at facilitating sustainable chemistry. As a consequence of their unusual physical properties, reusability, and eco-friendly nature, ionic liquids have attracted the attention of organic chemists. Numerous reports have revealed that many catalysts and reagents were supported in the ionic liquid phase, resulting in enhanced reactivity and selectivity in various important reaction transformations. However, synthetic chemists cannot ignore the stability data and intermolecular interactions, or even reactions that are directly applicable to organic reactions in ionic liquids. It is becoming evident from the increasing number of reports on use of ionic liquids as solvents, catalysts, and reagents in organic synthesis that they are not totally inert under many reaction conditions. While in some cases, their unexpected reactivity has proven fortuitous and in others, it is imperative that when selecting an ionic liquid for a particular synthetic application, attention must be paid to its compatibility with the reaction conditions. Even though, more than 200 room temperature ionic liquids are known, only a few reports have commented their effects on reaction mechanisms or rate/stability. Therefore, rather than attempting to give a comprehensive overview of ionic liquid chemistry, this review focuses on the non-innocent nature of ionic liquids, with a decided emphasis to clearly illuminate the ability of ionic liquids to affect the mechanistic aspects of some organic reactions thereby affecting and promoting the yield and selectivity.

On the chemical stabilities of ionic liquids.

Science.gov (United States)

Sowmiah, Subbiah; Srinivasadesikan, Venkatesan; Tseng, Ming-Chung; Chu, Yen-Ho

2009-09-25

Ionic liquids are novel solvents of interest as greener alternatives to conventional organic solvents aimed at facilitating sustainable chemistry. As a consequence of their unusual physical properties, reusability, and eco-friendly nature, ionic liquids have attracted the attention of organic chemists. Numerous reports have revealed that many catalysts and reagents were supported in the ionic liquid phase, resulting in enhanced reactivity and selectivity in various important reaction transformations. However, synthetic chemists cannot ignore the stability data and intermolecular interactions, or even reactions that are directly applicable to organic reactions in ionic liquids. It is becoming evident from the increasing number of reports on use of ionic liquids as solvents, catalysts, and reagents in organic synthesis that they are not totally inert under many reaction conditions. While in some cases, their unexpected reactivity has proven fortuitously advantageous in others is has been a problem, it is imperative that when selecting an ionic liquid for a particular synthetic application, attention be paid to its compatibility with the reaction conditions. Even though, more than 200 room temperature ionic liquids are known, only a few reports have commented their effects on reaction mechanisms or rate/stability. Therefore, rather than attempting to give a comprehensive overview of ionic liquid chemistry, this review focuses on the non-innocent nature of ionic liquids, with a decided emphasis to clearly illuminate the ability of ionic liquids to affect the mechanistic aspects of some organic reactions thereby affecting and promoting the yield and selectivity.

Ionic liquid-tolerant cellulase enzymes

Science.gov (United States)

Gladden, John; Park, Joshua; Singer, Steven; Simmons, Blake; Sale, Ken

2017-10-31

The present invention provides ionic liquid-tolerant cellulases and method of producing and using such cellulases. The cellulases of the invention are useful in saccharification reactions using ionic liquid treated biomass.

Recent development of ionic liquid membranes

Directory of Open Access Journals (Sweden)

Junfeng Wang

2016-04-01

Full Text Available The interest in ionic liquids (IL is motivated by its unique properties, such as negligible vapor pressure, thermal stability, wide electrochemical stability window, and tunability of properties. ILs have been highlighted as solvents for liquid–liquid extraction and liquid membrane separation. To further expand its application in separation field, the ionic liquid membranes (ILMs and its separation technology have been proposed and developed rapidly. This paper is to give a comprehensive overview on the recent applications of ILMs for the separation of various compounds, including organic compounds, mixed gases, and metal ions. Firstly, ILMs was classified into supported ionic liquid membranes (SILMs and quasi-solidified ionic liquid membranes (QSILMs according to the immobilization method of ILs. Then, preparation methods of ILMs, membrane stability as well as applications of ILMs in the separation of various mixtures were reviewed. Followed this, transport mechanisms of gaseous mixtures and organic compounds were elucidated in order to better understand the separation process of ILMs. This tutorial review intends to not only offer an overview on the development of ILMs but also provide a guide for ILMs preparations and applications. Keywords: Ionic liquid membrane, Supported ionic liquid membrane, Qusai-solidified ionic liquid membrane, Stability, Application

Division of Atomic Physics. Lund Institute of Technology. Progress Report 1993-1994

International Nuclear Information System (INIS)

Wahlstroem, C.G.

1995-01-01

The Division of Atomic Physics is responsible for basic physics teaching in all engineering disciplines and for specialized teaching in Optics, Atomic Physics, Spectroscopy, Laser Physics, and Non-Linear Optics. Research activities are mainly carried out in the fields of basic and applied spectroscopy, largely based on the use of lasers. Projects in the following areas are reported: Basic Atomic Physics - Atomic physics with high power laser radiation; Laser spectroscopic investigations of atomic and ionic excited states in the short-wavelength region; Laser spectroscopy in the visible; Theoretical Atomic Physics; Applied Optics and Quantum Electronics -High resolution spectroscopy; Photon echoes in Rare Earth Ion Doped Crystals; diode laser Spectroscopy; Environmental Remote Sensing -Tropospheric Ozone Lidar; Measurement of gases of geophysical origin; Industrial and Urban Pollution Measurements; Laser induced fluorescence of vegetation and water; Applications in Medicine and Biology - Tissue diagnostic using Laser-induced fluorescence; Photodynamic Therapy; Measurement of Optical Properties of Tissue with applications to Diagnostics; Two Photon Excited fluorescence Microscopy; Capillary Electrophoresis; New Techniques; Industrial Applications - Optical spectroscopy in Metallurgy; Physics of Electric Breakdown in Dielectric liquids; Optical Spectroscopy of Paper

Division of Atomic Physics. Lund Institute of Technology. Progress Report 1993-1994

Energy Technology Data Exchange (ETDEWEB)

Wahlstroem, C.G. [ed.

1995-12-31

The Division of Atomic Physics is responsible for basic physics teaching in all engineering disciplines and for specialized teaching in Optics, Atomic Physics, Spectroscopy, Laser Physics, and Non-Linear Optics. Research activities are mainly carried out in the fields of basic and applied spectroscopy, largely based on the use of lasers. Projects in the following areas are reported: Basic Atomic Physics - Atomic physics with high power laser radiation; Laser spectroscopic investigations of atomic and ionic excited states in the short-wavelength region; Laser spectroscopy in the visible; Theoretical Atomic Physics; Applied Optics and Quantum Electronics -High resolution spectroscopy; Photon echoes in Rare Earth Ion Doped Crystals; diode laser Spectroscopy; Environmental Remote Sensing -Tropospheric Ozone Lidar; Measurement of gases of geophysical origin; Industrial and Urban Pollution Measurements; Laser induced fluorescence of vegetation and water; Applications in Medicine and Biology - Tissue diagnostic using Laser-induced fluorescence; Photodynamic Therapy; Measurement of Optical Properties of Tissue with applications to Diagnostics; Two Photon Excited fluorescence Microscopy; Capillary Electrophoresis; New Techniques; Industrial Applications - Optical spectroscopy in Metallurgy; Physics of Electric Breakdown in Dielectric liquids; Optical Spectroscopy of Paper.

Division of Atomic Physics. Lund Institute of Technology. Progress Report 1993-1994

Energy Technology Data Exchange (ETDEWEB)

Wahlstroem, C G [ed.

1996-12-31

The Division of Atomic Physics is responsible for basic physics teaching in all engineering disciplines and for specialized teaching in Optics, Atomic Physics, Spectroscopy, Laser Physics, and Non-Linear Optics. Research activities are mainly carried out in the fields of basic and applied spectroscopy, largely based on the use of lasers. Projects in the following areas are reported: Basic Atomic Physics - Atomic physics with high power laser radiation; Laser spectroscopic investigations of atomic and ionic excited states in the short-wavelength region; Laser spectroscopy in the visible; Theoretical Atomic Physics; Applied Optics and Quantum Electronics -High resolution spectroscopy; Photon echoes in Rare Earth Ion Doped Crystals; diode laser Spectroscopy; Environmental Remote Sensing -Tropospheric Ozone Lidar; Measurement of gases of geophysical origin; Industrial and Urban Pollution Measurements; Laser induced fluorescence of vegetation and water; Applications in Medicine and Biology - Tissue diagnostic using Laser-induced fluorescence; Photodynamic Therapy; Measurement of Optical Properties of Tissue with applications to Diagnostics; Two Photon Excited fluorescence Microscopy; Capillary Electrophoresis; New Techniques; Industrial Applications - Optical spectroscopy in Metallurgy; Physics of Electric Breakdown in Dielectric liquids; Optical Spectroscopy of Paper.

Crystal structure of di-methyl-formamidium bis-(tri-fluoro-methane-sulfon-yl)amide: an ionic liquid.

Science.gov (United States)

Cardenas, Allan Jay P; O'Hagan, Molly

2016-09-01

At 100 K, the title mol-ecular salt, C 3 H 8 NO + ·C 2 F 6 NO 4 S 2 - , has ortho-rhom-bic ( P 2 1 2 1 2 1 ) symmetry; the amino H atom of bis-(tri-fluoro-methane-sulfon-yl)amine (HNTf 2 ) was transferred to the basic O atom of di-methyl-formamide (DMF) when the ionic liquid components were mixed. The structure displays an O-H⋯N hydrogen bond, which links the cation to the anion, which is reinforced by a non-conventional C-H⋯O inter-action, generating an R 2 2 (7) loop. A further very weak C-H⋯O inter-action generates an [001] chain.

Structure of ordered polyelectrolyte films from atomic-force microscopy and X-ray reflectivity data

International Nuclear Information System (INIS)

Belyaev, V.V.; Tolstikhina, A.L.; Stepina, N.D.; Kayushina, R.L.

1998-01-01

The possible application of atomic-force microscopy and X-ray reflectometry methods to structural studies of polyelectrolyte films obtained due to alternating adsorption of oppositely charged polyanion [sodium polysterenesulfonate (PSS)] and polycation [poly(allylamine) hydrochloride (PAA)] layers on solid substrates has been considered. The atomic-force microscopy study has revealed the characteristic features of the surface topography of samples consisting of different numbers of polyelectrolyte layers deposited from solutions characterized by different ionic strength values. It is shown that the shape of the reflectivity curves obtained from thin polyelectrolyte films depends on their surface structure

Lunar Oxygen Production and Metals Extraction Using Ionic Liquids

Science.gov (United States)

Marone, Matthew; Paley, Mark Steven; Donovan, David N.; Karr, Laurel J.

2009-01-01

Initial results indicate that ionic liquids are promising media for the extraction of oxygen from lunar regolith. IL acid systems can solubilize regolith and produce water with high efficiency. IL electrolytes are effective for water electrolysis, and the spent IL acid media are capable of regeneration.

A New Class of Solvents for TRU Dissolution and Separation: Ionic Liquids. Project No. 81891

International Nuclear Information System (INIS)

Rogers, Robin D.

2004-01-01

Through the current EMSP funding, solvent extraction technologies based on liquid-liquid partitioning of TRU to an Ionic Liquid phase containing conventional complexants has been shown to be viable. The growing understanding of the role that the different components of an ionic liquid can have on the partitioning mechanism, and on the nature of the subsequent dissolved species indicates strongly that ionic liquids are not necessarily direct replacements for volatile or otherwise hazardous organic solvents. Separations and partitioning can be exceptionally complex with competing solvent extraction, cation, anion and sacrificial ion exchange mechanisms are all important, depending on the selection of components for formation of the ionic liquid phase, and that control of these competing mechanisms can be utilized to provide new, alternative separations schemes

Lattice dynamics of ionic crystals

International Nuclear Information System (INIS)

Mahan, G.D.

1990-01-01

The theory of lattice dynamics for ionic and rare-gas crystals is derived in the harmonic approximation. We start from a Hamiltonian and average over electron coordinates in order to obtain an effective interaction between ion displacements. We assume that electronic excitations are localized on a single ion, which limits the theory to ionic crystals. The deformation-dipole model and the indirect-ionic-interaction model are derived. These two contributions are closely linked, and together provide an accurate description of short-range forces

CADDIS Volume 2. Sources, Stressors and Responses: Ionic Strength

Science.gov (United States)

Introduction to the ionic strength module, when to list ionic strength as a candidate cause, ways to measure ionic strength, simple and detailed conceptual diagrams for ionic strength, ionic strength module references and literature reviews.

Ionic conductivity studies of gel polyelectrolyte based on ionic liquid

Energy Technology Data Exchange (ETDEWEB)

Cha, E.H. [The Faculty of Liberal Arts (Chemistry), Hoseo University, Asan Choongnam 336-795 (Korea); Lim, S.A. [Functional Proteomics Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea); Park, J.H. [Department of Herbal Medicine, Hoseo University, Asan Choongnam 336-795 (Korea); Kim, D.W. [Department of Chemical Technology, Han Bat National University, Daejon 305-719 (Korea); Macfarlane, D.R. [School of Chemistry, Monash University, Clayton, Vic. 3800 (Australia)

2008-04-01

Novel lithium polyelectrolyte-ionic liquids have been prepared and characterized of their properties. Poly(lithium 2-acrylamido-2-methyl propanesulfonate) (PAMPSLi) and its copolymer with N-vinyl formamide (VF) also has been prepared as a copolymer. 1-Ethyl-3-methylimidazolium tricyanomethanide (emImTCM) and N,N-dimethyl-N-propyl-N-butyl ammonium tricyanomethanide (N{sub 1134}TCM) which are chosen because of the same with the anion of ionic liquid were prepared. The ionic conductivity of copolymer system (PAMPSLi/PVF/emImTCM: 5.43 x 10{sup -3} S cm{sup -1} at 25 C) exhibits about over four times higher than that of homopolymer system (PAMPSLi/emImTCM: 1.28 x 10{sup -3} S cm{sup -1} at 25 C). Introduction of vinyl formamide into the copolymer type can increase the dissociation of the lithium cations from the polymer backbone. The ionic conductivity of copolymer with emImTCM (PAMPSLi/PVF/emImTCM) exhibits the higher conductivity than that of PAMPSLi/PVF/N{sub 1134}TCM (2.48 x 10{sup -3} S cm{sup -1}). Because of using the polymerizable anion it is seen to maintain high flexibility of imidazolium cation effectively to exhibit the higher conductivity. And also the viscosity of emImTCM (19.56 cP) is lower than that of N{sub 1134}TCM (28.61 cP). Low viscosity leads to a fast rate of diffusion of redox species. (author)

Ionic conducting poly-benzimidazoles

International Nuclear Information System (INIS)

Jouanneau, J.

2006-11-01

Over the last years, many research works have been focused on new clean energy systems. Hydrogen fuel cell seems to be the most promising one. However, the large scale development of this technology is still limited by some key elements. One of them is the polymer electrolyte membrane 'Nafion' currently used, for which the ratio performance/cost is too low. The investigations we carried out during this thesis work are related to a new class of ionic conducting polymer, the sulfonated poly-benzimidazoles (sPBI). Poly-benzimidazoles (PBI) are aromatic heterocyclic polymers well-known for their excellent thermal and chemical stability. Ionic conduction properties are obtained by having strong acid groups (sulfonic acid SO 3 H) on the macromolecular structure. For that purpose, we first synthesized sulfonated monomers. Their poly-condensation with an appropriate non-sulfonated co-monomer yields to sPBI with sulfonation range from 0 to 100 per cent. Three different sPBI structures were obtained, and verified by appropriate analytical techniques. We also showed that the protocol used for the synthesis resulted in high molecular weights polymers. We prepared ionic conducting membrane by casting sPBI solutions on glass plates. Their properties of stability, water swelling and ionic conductivity were investigated. Surprisingly, the behaviour of sPBI was quite different from the other sulfonated aromatic polymers with same amount of SO 3 H, their stability was much higher, but their water swelling and ionic conductivity were quite low. We attributed these differences to strong ionic interactions between the sulfonic acid groups and the basic benzimidazole groups of our polymers. However, we managed to solve this problem synthesizing very highly sulfonated PBI, obtaining membranes with a good balance between all the properties necessary. (author)

The development of high-resolution spectroscopic methods and their use in atomic structure studies

International Nuclear Information System (INIS)

Poulsen, O.

1984-01-01

This thesis discusses work performed during the last nine years in the field of atomic spectroscopy. Several high-resolution techniques, ranging from quantum beats, level crossings, rf-laser double resonances to nonlinear field atom interactions, have been employed. In particular, these methods have been adopted and developed to deal with fast accelerated atomic or ionic beams, allowing studies of problems in atomic-structure theory. Fine- and hyperfine-structure determinations in the He I and Li I isoelectronic sequences, in 51 V I, and in 235 U I, II have permitted a detailed comparison with ab initio calculations, demonstrating the change in problems when going towards heavier elements or higher ionization stage. The last part of the thesis is concerned with the fundamental question of obtaining very high optical resolution in the interaction between a fast accelerated atom or ion beam and a laser field, this problem being the core in the continuing development of atomic spectroscopy necessary to challenge the more precise and sophisticated theories advanced. (Auth.)

Directed Atom-by-Atom Assembly of Dopants in Silicon.

Science.gov (United States)

Hudak, Bethany M; Song, Jiaming; Sims, Hunter; Troparevsky, M Claudia; Humble, Travis S; Pantelides, Sokrates T; Snijders, Paul C; Lupini, Andrew R

2018-05-17

The ability to controllably position single atoms inside materials is key for the ultimate fabrication of devices with functionalities governed by atomic-scale properties. Single bismuth dopant atoms in silicon provide an ideal case study in view of proposals for single-dopant quantum bits. However, bismuth is the least soluble pnictogen in silicon, meaning that the dopant atoms tend to migrate out of position during sample growth. Here, we demonstrate epitaxial growth of thin silicon films doped with bismuth. We use atomic-resolution aberration-corrected imaging to view the as-grown dopant distribution and then to controllably position single dopants inside the film. Atomic-scale quantum-mechanical calculations corroborate the experimental findings. These results indicate that the scanning transmission electron microscope is of particular interest for assembling functional materials atom-by-atom because it offers both real-time monitoring and atom manipulation. We envision electron-beam manipulation of atoms inside materials as an achievable route to controllable assembly of structures of individual dopants.

Electrochemical Polishing Applications and EIS of a Vitamin B4-Based Ionic Liquid

International Nuclear Information System (INIS)

Wixtrom, Alex I.; Buhler, Jessica E.; Reece, Charles E.; Abdel-Fattah, Tarek M.

2013-01-01

Modern particle accelerators require minimal interior surface roughness for Niobium superconducting radio frequency (SRF) cavities. Polishing of the Nb is currently achieved via electrochemical polishing with concentrated mixtures of sulfuric and hydrofluoric acids. This acid-based approach is effective at reducing the surface roughness to acceptable levels for SRF use, but due to acid-related hazards and extra costs (including safe disposal of used polishing solutions), an acid-free method would be preferable. This study focuses on an alternative electrochemical polishing method for Nb, using a novel ionic liquid solution containing choline chloride, also known as Vitamin B 4 (VB 4 ). Potentiostatic electrochemical impedance spectroscopy (EIS) was also performed on the VB4-based system. Nb polished using the VB4-based method was found to have a final surface roughness comparable to that achieved via the acid-based method, as assessed by atomic force microscopy (AFM). These findings indicate that acid-free VB 4 -based electrochemical polishing of Nb represents a promising replacement for acid-based methods of SRF cavity preparation

Formation of Gd coordination polymer with 1D chains mediated by Bronsted acidic ionic liquids

Energy Technology Data Exchange (ETDEWEB)

Luo, Qianqian; Han, Ying [Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai (China); Lin, Hechun, E-mail: hclin@ee.ecnu.edu.cn [Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai (China); Zhang, Yuanyuan; Duan, Chungang [Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai (China); Peng, Hui, E-mail: hpeng@ee.ecnu.edu.cn [Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai (China); Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006 (China)

2017-03-15

One dimensional coordination polymer Gd[(SO{sub 4})(NO{sub 3})(C{sub 2}H{sub 6}SO){sub 2}] (1) is prepared through the mediation of Bronsted acid ionic liquid, which crystallized in the monoclinic space of C2/c. In this polymer, adjacent Gd atoms are linked by two SO{sub 4}{sup 2-} ions to generate a 1-D chain, and all oxygen atoms in SO{sub 4}{sup 2-} groups are connected to three nearest Gd atoms in µ{sup 3}:η{sup 1}:η{sup 1}:η{sup 2} fashion. Gd, S and N from SO{sub 4}{sup 2-} and NO{sub 3}{sup -} are precisely coplanar. The planar is coordinated by a pair of DMSO molecules, which is parallel and linked by hydrogen bonding to form a three-dimensional supramolecular network. Magnetic susceptibility measurement of 1 reveals weak antiferromagnetic interactions between the Gd (III) ions. It exhibits relatively large magneto-caloric effect with –ΔS{sub m}=28.8 J Kg{sup −1} K{sup −1} for ΔH=7 T. - Graphical abstract: Coordination polymer Gd[(SO{sub 4})(NO{sub 3})(C{sub 2}H{sub 6}SO){sub 2}] was obtained mediated by Bronsted acid Ionic Liquid, which presents a 1-D chains collected by SO{sub 4}{sup 2-} groups. Magnetic susceptibility of the polymer reveals weak antiferromagnetic interactions between the Gd(III) ions with the relatively large magneto-caloric effect of –ΔS{sub m}=28.8 J Kg{sup −1} K{sup −1} for ΔH= 7T.

Ionic Exchange of Metal-Organic Frameworks to Access Single Nickel Sites for Efficient Electroreduction of CO2.

Science.gov (United States)

Zhao, Changming; Dai, Xinyao; Yao, Tao; Chen, Wenxing; Wang, Xiaoqian; Wang, Jing; Yang, Jian; Wei, Shiqiang; Wu, Yuen; Li, Yadong

2017-06-21

Single-atom catalysts often exhibit unexpected catalytic activity for many important chemical reactions because of their unique electronic and geometric structures with respect to their bulk counterparts. Herein we adopt metal-organic frameworks (MOFs) to assist the preparation of a catalyst containing single Ni sites for efficient electroreduction of CO 2 . The synthesis is based on ionic exchange between Zn nodes and adsorbed Ni ions within the cavities of the MOF. This single-atom catalyst exhibited an excellent turnover frequency for electroreduction of CO 2 (5273 h -1 ), with a Faradaic efficiency for CO production of over 71.9% and a current density of 10.48 mA cm -2 at an overpotential of 0.89 V. Our findings present some guidelines for the rational design and accurate modulation of nanostructured catalysts at the atomic scale.

Ionic-Liquid-Tethered Nanoparticles: Hybrid Electrolytes

KAUST Repository

Moganty, Surya S.

2010-10-22

A new class of solventless electrolytes was created by tethering ionic liquids to hard inorganic ZrO2 nanostructures (see picture; NIM=nanoscale ionic material). These hybrid fluids exhibit exceptional redox stability windows, excellent thermal stability, good lithium transference numbers, long-term interfacial stability in the presence of a lithium anode and, when doped with lithium salt, reasonable ionic conductivities.

Thermochemistry of ionic liquid heat-transfer fluids

International Nuclear Information System (INIS)

Van Valkenburg, Michael E.; Vaughn, Robert L.; Williams, Margaret; Wilkes, John S.

2005-01-01

Large-scale solar energy collectors intended for electric power generation require a heat-transfer fluid with a set of properties not fully met by currently available commercial materials. Ionic liquids have thermophysical and chemical properties that may be suitable for heat transfer and short heat term storage in power plants using parabolic trough solar collectors. Ionic liquids are salts that are liquid at or near room temperature. Thermal properties important for heat transfer applications are melting point, boiling point, liquidus range, heat capacity, heat of fusion, vapor pressure, and thermal conductivity. Other properties needed to evaluate the usefulness of ionic liquids are density, viscosity and chemical compatibility with certain metals. Three ionic liquids were chosen for study based on their range of solvent properties. The solvent properties correlate with solubility of water in the ionic liquids. The thermal and chemical properties listed above were measured or compiled from the literature. Contamination of the ionic liquids by impurities such as water, halides, and metal ions often affect physical properties. The ionic liquids were analyzed for those impurities, and the impact of the contamination was evaluated by standard addition. The conclusion is that the ionic liquids have some very favorable thermal properties compared to targets established by the Department of Energy for solar collector applications

Toward protic ionic liquid and organic ionic plastic crystal electrolytes for fuel cells

International Nuclear Information System (INIS)

Rana, Usman Ali; Forsyth, Maria; MacFarlane, Douglas R.; Pringle, Jennifer M.

2012-01-01

Highlights: ► Polymer electrolyte membrane fuel cells that can operate above 120 °C, without humidification, would be much more commercially viable. ► Protic ionic liquids and organic ionic plastic crystals are showing increasing promise as anhydrous proton conductors in fuel cells. ► Here we review the recent progress in these two areas. - Abstract: There is increasing demand for the development of anhydrous proton conducting electrolytes, most notably to allow the development of fuel cells that can operate at temperatures above 120 °C, without the need for constant and controlled humidification. The emerging field of protic ionic liquids (PILs) represents a promising new direction for this research and the development of these materials has made significant progress in recent years. In a related but as yet little-explored avenue, proton conducting organic ionic plastic crystals offer the potential advantage of providing a solid state matrix for anhydrous proton conductivity. Here we discuss the recent progress in these areas and identify the key challenges for future research.

Disinfection of Spacecraft Potable Water Systems by Passivation with Ionic Silver

Science.gov (United States)

Birmele, Michele N.; McCoy, LaShelle e.; Roberts, Michael S.

2011-01-01

Microbial growth is common on wetted surfaces in spacecraft environmental control and life support systems despite the use of chemical and physical disinfection methods. Advanced control technologies are needed to limit microorganisms and increase the reliability of life support systems required for long-duration human missions. Silver ions and compounds are widely used as antimicrobial agents for medical applications and continue to be used as a residual biocide in some spacecraft water systems. The National Aeronautics and Space Administration (NASA) has identified silver fluoride for use in the potable water system on the next generation spacecraft. Due to ionic interactions between silver fluoride in solution and wetted metallic surfaces, ionic silver is rapidly depleted from solution and loses its antimicrobial efficacy over time. This report describes research to prolong the antimicrobial efficacy of ionic silver by maintaining its solubility. Three types of metal coupons (lnconel 718, Stainless Steel 316, and Titanium 6AI-4V) used in spacecraft potable water systems were exposed to either a continuous flow of water amended with 0.4 mg/L ionic silver fluoride or to a static, pre-treatment passivation in 50 mg/L ionic silver fluoride with or without a surface oxidation pre-treatment. Coupons were then challenged in a high-shear, CDC bioreactor (BioSurface Technologies) by exposure to six bacteria previously isolated from spacecraft potable water systems. Continuous exposure to 0.4 mg/L ionic silver over the course of 24 hours during the flow phase resulted in a >7-log reduction. The residual effect of a 24-hour passivation treatment in 50 mg/L of ionic silver resulted in a >3-log reduction, whereas a two-week treatment resulted in a >4-log reduction. Results indicate that 0.4 mg/L ionic silver is an effective biocide against many bacteria and that a prepassivation of metal surfaces with silver can provide additional microbial control.

Picosecond radiolysis of ionic liquids

International Nuclear Information System (INIS)

Funston, A.M.; Wishart, J.F.; Neta, P.; Lall, S.I.; Engel, R.

2003-01-01

Ionic liquids (ILs) are a rapidly expanding family of condensed-phase media with important applications in nuclear fuel and waste processing, energy production, improving the efficiency and safety of industrial chemical processes, and pollution prevention. Ionic liquids are completely nonvolatile, noncombustible, highly conductive, recyclable and capable of dissolving a wide variety of materials. An understanding of the radiation chemistry of ionic liquids is important for development of their applications in radioactive material processing and for the application of pulse radiolysis techniques to the general study of chemical reactivity in ionic liquids. Kinetic studies with a picosecond electron accelerator, such as the BNL Laser-Electron Accelerator Facility (LEAF), allow one to observe primary radiation products and their reactions on short time scales. For example, the solvated electron lifetime in neat methyltributylammonium bis(trifluoromethylsulfonyl)imide is ∼300 ns and its absorption maximum is ∼1400 nm. Kinetic studies of primary radiolytic products and their reactivities will be described for several types of ionic liquids. Supported in part by the U.S. Department of Energy, Division of Chemical Sciences, Office of Basic Energy Sciences, under contract DE-AC02-98-CH1088

Thermophysical properties of ionic liquids.

Science.gov (United States)

Rooney, David; Jacquemin, Johan; Gardas, Ramesh

2010-01-01

Low melting point salts which are often classified as ionic liquids have received significant attention from research groups and industry for a range of novel applications. Many of these require a thorough knowledge of the thermophysical properties of the pure fluids and their mixtures. Despite this need, the necessary experimental data for many properties is scarce and often inconsistent between the various sources. By using accurate data, predictive physical models can be developed which are highly useful and some would consider essential if ionic liquids are to realize their full potential. This is particularly true if one can use them to design new ionic liquids which maximize key desired attributes. Therefore there is a growing interest in the ability to predict the physical properties and behavior of ionic liquids from simple structural information either by using group contribution methods or directly from computer simulations where recent advances in computational techniques are providing insight into physical processes within these fluids. Given the importance of these properties this review will discuss the recent advances in our understanding, prediction and correlation of selected ionic liquid physical properties.

Evaluation of Vapor Pressure and Ultra-High Vacuum Tribological Properties of Ionic Liquids (2) Mixtures and Additives

Science.gov (United States)

Morales, Wilfredo; Koch, Victor R.; Street, Kenneth W., Jr.; Richard, Ryan M.

2008-01-01

Ionic liquids are salts, many of which are typically viscous fluids at room temperature. The fluids are characterized by negligible vapor pressures under ambient conditions. These properties have led us to study the effectiveness of ionic liquids containing both organic cations and anions for use as space lubricants. In the previous paper we have measured the vapor pressure and some tribological properties of two distinct ionic liquids under simulated space conditions. In this paper we will present vapor pressure measurements for two new ionic liquids and friction coefficient data for boundary lubrication conditions in a spiral orbit tribometer using stainless steel tribocouples. In addition we present the first tribological data on mixed ionic liquids and an ionic liquid additive. Post mortem infrared and Raman analysis of the balls and races indicates the major degradation pathway for these two organic ionic liquids is similar to those of other carbon based lubricants, i.e. deterioration of the organic structure into amorphous graphitic carbon. The coefficients of friction and lifetimes of these lubricants are comparable to or exceed these properties for several commonly used space oils.

Membrane separation of ionic liquid solutions

Science.gov (United States)

Campos, Daniel; Feiring, Andrew Edward; Majumdar, Sudipto; Nemser, Stuart

2015-09-01

A membrane separation process using a highly fluorinated polymer membrane that selectively permeates water of an aqueous ionic liquid solution to provide dry ionic liquid. Preferably the polymer is a polymer that includes polymerized perfluoro-2,2-dimethyl-1,3-dioxole (PDD). The process is also capable of removing small molecular compounds such as organic solvents that can be present in the solution. This membrane separation process is suitable for drying the aqueous ionic liquid byproduct from precipitating solutions of biomass dissolved in ionic liquid, and is thus instrumental to providing usable lignocellulosic products for energy consumption and other industrial uses in an environmentally benign manner.

Isobutane as a probe of the structure of 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquids

International Nuclear Information System (INIS)

Pison, Laure; Bernales, Varinia; Fuentealba, Patricio; Padua, Agilio A.H.

2015-01-01

Highlights: • The solubility of isobutane was determined in [C n C 1 Im][NTf 2 ] (n = 2, 4, 6, 8 and 10). • Iso-C 4 H 10 solubility decreases with T and increases with n to reach x = 0.1 (n = 10, T = 303 K). • Isobutane is, on average, 1.6 times less soluble than n-butane in this family of ionic liquids. • Solubility increase with n is due to a more negative enthalpy of dissolution (n ⩾ 6). - Abstract: An experimental study of the solubility and of the thermodynamic properties of solvation, between temperatures (303 and 343) K and at pressures close to atmospheric, of 2-methylpropane (isobutane) in several ionic liquids based on the bis(trifluoromethylsulfonyl)imide anion and on 1-alkyl-3-methylimidazolium cations, [C n C 1 Im][NTf 2 ], with alkyl side-chains varying from two to ten carbon atoms is presented. The isobutane solubility increases with increasing size of the alkyl side-chain of the cation in the ionic liquid and decreases with increasing temperature (as typical of an exothermal dissolution process). The mole fraction solubility of isobutane varies from 0.904 · 10 −2 in [C 2 C 1 Im][NTf 2 ] at T = 343 K to 1.002 · 10 −1 in [C 10 C 1 Im][NTf 2 ] at T = 303 K. The values measured in this work are compared to the behaviour of n-butane in the same ionic liquids published in a previous study (Costa Gomes et al., 2012). Isobutane was found to be significantly less soluble than n-butane in all the ionic liquids. The differences found are interpreted in relation to the molecular structures obtained by molecular dynamics simulations for the solutions of n-butane and isobutane in the studied [C n C 1 Im][NTf 2 ] ionic liquids

Ionic liquid and nanoparticle hybrid systems: Emerging applications.

Science.gov (United States)

He, Zhiqi; Alexandridis, Paschalis

2017-06-01

Having novel electronic and optical properties that emanate from their nano-scale dimensions, nanoparticles are central to numerous applications. Ionic liquids can confer to nanoparticle chemical protection and physicochemical property enhancement through intermolecular interactions and can consequently improve the stability and reusability of nanoparticle for various operations. With an aim to combine the novel properties of nanoparticles and ionic liquids, different structures have been generated, based on a balance of several intermolecular interactions. Such ionic liquid and nanoparticle hybrids are showing great potential in diverse applications. In this review, we first introduce various types of ionic liquid and nanoparticle hybrids, including nanoparticle colloidal dispersions in ionic liquids, ionic liquid-grafted nanoparticles, and nanoparticle-stabilized ionic liquid-based emulsions. Such hybrid materials exhibit interesting synergisms. We then highlight representative applications of ionic liquid and nanoparticle hybrids in the catalysis, electrochemistry and separations fields. Such hybrids can attain better stability and higher efficiency under a broad range of conditions. Novel and enhanced performance can be achieved in these applications by combining desired properties of ionic liquids and of nanoparticles within an appropriate hybrid nanostructure. Copyright © 2016 Elsevier B.V. All rights reserved.

Fast Ignition and Sustained Combustion of Ionic Liquids

Science.gov (United States)

Joshi, Prakash B. (Inventor); Piper, Lawrence G. (Inventor); Oakes, David B. (Inventor); Sabourin, Justin L. (Inventor); Hicks, Adam J. (Inventor); Green, B. David (Inventor); Tsinberg, Anait (Inventor); Dokhan, Allan (Inventor)

2016-01-01

A catalyst free method of igniting an ionic liquid is provided. The method can include mixing a liquid hypergol with a HAN (Hydroxylammonium nitrate)-based ionic liquid to ignite the HAN-based ionic liquid in the absence of a catalyst. The HAN-based ionic liquid and the liquid hypergol can be injected into a combustion chamber. The HAN-based ionic liquid and the liquid hypergol can impinge upon a stagnation plate positioned at top portion of the combustion chamber.

Task-specific ionic liquids for solubilizing metal compounds

OpenAIRE

Thijs, Ben

2007-01-01

The main goal of this PhD thesis was to design new task-specific ionic liquids with the ability to dissolve metal compounds. Despite the large quantity of papers published on ionic liquids, not much is known about the mechanisms of dissolving metals in ionic liquids or about metal-containing ionic liquids. Additionally, many of the commercially available ionic liquids exhibit a very limited solubilizing power for metal compounds, although this is for many applications like electrodeposition a...

Supercritical fluids in ionic liquids

NARCIS (Netherlands)

Kroon, M.C.; Peters, C.J.; Plechkova, N.V.; Seddon, K.R.

2014-01-01

Ionic liquids and supercritical fluids are both alternative environmentally benign solvents, but their properties are very different. Ionic liquids are non-volatile but often considered highly polar compounds, whereas supercritical fluids are non-polar but highly volatile compounds. The combination

Comparison of soft tissue effects of conventional ionic, low osmolar ionic and nonionic iodine containing contrast material in experimental animals

International Nuclear Information System (INIS)

McAlister, W.H.; Kissane, J.M.

1990-01-01

Conventional, low osmolar, and non-ionic iodine containing contrast media and saline controls were placed in the paws, muscles, and subcutaneous tissues of Sprague-Dawley rat thighs. The paw injections were observed and photographed, while the thighs were examined histologically. Results showed that although the low osmolar and non-ionic agents did produce inflammatory reactions and focal necrosis in the soft tissues, they were much better tolerated than were the conventional ionic agents. A non-ionic or low osmolar ionic contrast agent should be strongly considered when a possibility for extravasation exists. (orig.)

Energetic Metastable Oxygen and Nitrogen Atoms in the Terrestrial Atmosphere

Science.gov (United States)

Kharchenko, Vasili; Dalgarno, A.

2005-01-01

This report summarizes our research performed under NASA Grant NAG5-11857. The three-year grant have been supported by the Geospace Sciences SR&T program. We have investigated the energetic metastable oxygen and nitrogen atoms in the terrestrial stratosphere, mesosphere and thermosphere. Hot atoms in the atmosphere are produced by solar radiation, the solar wind and various ionic reactions. Nascent hot atoms arise in ground and excited electronic states, and their translational energies are larger by two - three orders of magnitude than the thermal energies of the ambient gas. The relaxation kinetics of hot atoms determines the rate of atmospheric heating, the intensities of aeronomic reactions, and the rate of atom escape from the planet. Modeling of the non-Maxwellian energy distributions of metastable oxygen and nitrogen atoms have been focused on the determination of their impact on the energetics and chemistry of the terrestrial atmosphere between 25 and 250 km . At this altitudes, we have calculated the energy distribution functions of metastable O and N atoms and computed non-equilibrium rates of important aeronomic reactions, such as destruction of the water molecules by O(1D) atoms and production of highly excited nitric oxide molecules. In the upper atmosphere, the metastable O(lD) and N(2D) play important role in formation of the upward atomic fluxes. We have computed the upward fluxes of the metastable and ground state oxygen atoms in the upper atmosphere above 250 km. The accurate distributions of the metastable atoms have been evaluated for the day and night-time conditions.

Synthesis of hetero ionic compounds using dialkylcarbonate quaternization

Energy Technology Data Exchange (ETDEWEB)

Friesen, Cody A.; Wolfe, Derek; Johnson, Paul Bryan

2018-04-03

Methods of preparing hetero ionic complexes, and ionic liquids from bisulfate salts of heteroatomic compounds using dialkylcarbonates as a primary quaternizing reactant are disclosed. Also disclosed are methods of making electrochemical cells comprising the ionic liquids, and an electrochemical cell comprising an alkaline electrolyte and a hetero ionic complex additive.

Electrical double layer modulation of hybrid room temperature ionic liquid/aqueous buffer interface for enhanced sweat based biosensing.

Science.gov (United States)

Jagannath, Badrinath; Muthukumar, Sriram; Prasad, Shalini

2018-08-03

We have investigated the role of kosmotropic anionic moieties and chaotropic cationic moieties of room temperature hydrophilic ionic liquids in enhancing the biosensing performance of affinity based immunochemical biosensors in human sweat. Two ionic liquids, 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM[BF 4 ]) and choline dihydrogen phosphate (Choline[DHP]) were investigated in this study with Choline[DHP] being more kosmotropic in nature having a more protein stabilizing effect based on the hofmeister series. Non-faradaic interfacial charge transfer has been employed as the mechanism for evaluating the formation and the biosensing of capture probe antibodies in room temperature ionic liquids (RTILs)/aqueous human sweat interface. The charge of the ionic moieties were utilized to form compact electrical double layers around the antibodies for enhancing the stability of the antibody capture probes, which was evaluated through zeta potential measurements. The zeta potential measurements indicated stability of antibodies due to electrostatic repulsion of the RTIL charged moieties encompassing the antibodies, thus preventing any aggregation. Here, we report for the first time of non-faradaic electrochemical impedance spectroscopy equivalent circuit model analysis for analyzing and interpreting affinity based biosensing at hybrid electrode/ionic liquid-aqueous sweat buffer interface guided by the choice of the ionic liquid. Interleukin-6 (IL-6) and cortisol two commonly occurring biomarkers in human sweat were evaluated using this method. The limit of detection (LOD) obtained using both ionic liquids for IL-6 was 0.2 pg mL -1 with cross-reactivity studies indicating better performance of IL-6 detection using Choline[DHP] and no response to cross-reactive molecule. The LOD of 0.1 ng/mL was achieved for cortisol and the cross-reactivity studies indicated that cortisol antibody in BMIM[BF 4 ] did not show any signal response to cross-reactive molecules

A computer program for external modes in complex ionic crystals (the rigid molecular-ion model)

International Nuclear Information System (INIS)

Chaplot, S.L.

1978-01-01

A computer program DISPR has been developed to calculate the external mode phonon dispersion relation in the harmonic approximation for complex ionic crystals using the rigid molecular ion model. A description of the program, the flow diagram and the required input information are given. A sample calculation for α-KNO 3 is presented. The program can handle any type of crystal lattice with any number of atoms and molecules per unit cell with suitable changes in dimension statements. (M.G.B.)

Computation of electron-impact K-shell ionization cross sections of atoms

International Nuclear Information System (INIS)

Uddin, M.A.; Haque, A.K.F.; Billah, M. Masum; Basak, A.K.; Karim, K.R.; Saha, B.C.

2005-01-01

The total cross sections of electron impact single K-shell ionization of atomic targets, with a wide range of atomic numbers from Z=6-50, are evaluated in the energy range up to about 10 MeV employing the recently proposed modified version of the improved binary-encounter dipole (RQIBED) model [Uddin et al., Phys. Rev. A 70, 032706 (2004)], which incorporates the ionic and relativistic effects. The experimental cross sections for all targets are reproduced satisfactorily even in the relativistic energies using fixed generic values of the two parameters in the RQIBED model. The relativistic effect is found to be significant in all targets except for C, being profound in Ag and Sn

Ionic liquid-nanoparticle hybrid electrolytes

KAUST Repository

Lu, Yingying

2012-01-01

We investigate physical and electrochemical properties of a family of organic-inorganic hybrid electrolytes based on the ionic liquid 1-methyl-3-propylimidazolium bis(trifluoromethanesulfone) imide covalently tethered to silica nanoparticles (SiO 2-IL-TFSI). The ionic conductivity exhibits a pronounced maximum versus LiTFSI composition, and in mixtures containing 13.4 wt% LiTFSI, the room-temperature ionic conductivity is enhanced by over 3 orders of magnitude relative to either of the mixture components, without compromising lithium transference number. The SiO 2-IL-TFSI/LiTFSI hybrid electrolytes are thermally stable up to 400°C and exhibit tunable mechanical properties and attractive (4.25V) electrochemical stability in the presence of metallic lithium. We explain these observations in terms of ionic coupling between counterion species in the mobile and immobile (particle-tethered) phases of the electrolytes. © 2012 The Royal Society of Chemistry.

Role of atom--atom inelastic collisions in two-temperature nonequilibrium plasmas

International Nuclear Information System (INIS)

Kunc, J.A.

1987-01-01

The contribution of inelastic atom--atom collisions to the production of electrons and excited atoms in two-temperature (with electron temperature T/sub e/, atomic temperature T/sub a/, and atomic density N/sub a/), steady-state, nonequilibrium atomic hydrogen plasma is investigated. The results are valid for plasmas having large amounts of atomic hydrogen as one of the plasma components, so that e--H and H--H inelastic collisions and interaction of these atoms with radiation dominate the production of electrons and excited hydrogen atoms. Densities of electrons and excited atoms are calculated in low-temperature plasma, with T/sub e/ and T/sub a/≤8000 K and 10 16 cm -3 ≤N/sub a/≤10 18 cm -3 , and with different degrees of the reabsorption of radiation. The results indicate that inelastic atom--atom collisions are important for production of electrons and excited atoms in partially ionized plasmas with medium and high atomic density and temperatures below 8000 K

Nanoparticle enhanced ionic liquid heat transfer fluids

Science.gov (United States)

Fox, Elise B.; Visser, Ann E.; Bridges, Nicholas J.; Gray, Joshua R.; Garcia-Diaz, Brenda L.

2014-08-12

A heat transfer fluid created from nanoparticles that are dispersed into an ionic liquid is provided. Small volumes of nanoparticles are created from e.g., metals or metal oxides and/or alloys of such materials are dispersed into ionic liquids to create a heat transfer fluid. The nanoparticles can be dispersed directly into the ionic liquid during nanoparticle formation or the nanoparticles can be formed and then, in a subsequent step, dispersed into the ionic liquid using e.g., agitation.

Probing Lipid Bilayers under Ionic Imbalance.

Science.gov (United States)

Lin, Jiaqi; Alexander-Katz, Alfredo

2016-12-06

Biological membranes are normally under a resting transmembrane potential (TMP), which originates from the ionic imbalance between extracellular fluids and cytosols, and serves as electric power storage for cells. In cell electroporation, the ionic imbalance builds up a high TMP, resulting in the poration of cell membranes. However, the relationship between ionic imbalance and TMP is not clearly understood, and little is known about the effect of ionic imbalance on the structure and dynamics of biological membranes. In this study, we used coarse-grained molecular dynamics to characterize a dipalmitoylphosphatidylcholine bilayer system under ionic imbalances ranging from 0 to ∼0.06 e charges per lipid (e/Lip). We found that the TMP displayed three distinct regimes: 1) a linear regime between 0 and 0.045 e/Lip, where the TMP increased linearly with ionic imbalance; 2) a yielding regime between ∼0.045 and 0.060 e/Lip, where the TMP displayed a plateau; and 3) a poration regime above ∼0.060 e/Lip, where we observed pore formation within the sampling time (80 ns). We found no structural changes in the linear regime, apart from a nonlinear increase in the area per lipid, whereas in the yielding regime the bilayer exhibited substantial thinning, leading to an excess of water and Na + within the bilayer, as well as significant misalignment of the lipid tails. In the poration regime, lipid molecules diffused slightly faster. We also found that the fluid-to-gel phase transition temperature of the bilayer dropped below the normal value with increased ionic imbalances. Our results show that a high ionic imbalance can substantially alter the essential properties of the bilayer, making the bilayer more fluid like, or conversely, depolarization of a cell could in principle lead to membrane stiffening. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Toxicity of ionic liquids: Database and prediction via quantitative structure–activity relationship method

International Nuclear Information System (INIS)

Zhao, Yongsheng; Zhao, Jihong; Huang, Ying; Zhou, Qing; Zhang, Xiangping; Zhang, Suojiang

2014-01-01

Highlights: • A comprehensive database on toxicity of ionic liquids (ILs) was established. • Relationship between structure and toxicity of IL has been analyzed qualitatively. • Two new QSAR models were developed for predicting toxicity of ILs to IPC-81. • Accuracy of proposed nonlinear SVM model is much higher than the linear MLR model. • The established models can be explored in designing novel green agents. - Abstract: A comprehensive database on toxicity of ionic liquids (ILs) is established. The database includes over 4000 pieces of data. Based on the database, the relationship between IL's structure and its toxicity has been analyzed qualitatively. Furthermore, Quantitative Structure–Activity relationships (QSAR) model is conducted to predict the toxicities (EC 50 values) of various ILs toward the Leukemia rat cell line IPC-81. Four parameters selected by the heuristic method (HM) are used to perform the studies of multiple linear regression (MLR) and support vector machine (SVM). The squared correlation coefficient (R 2 ) and the root mean square error (RMSE) of training sets by two QSAR models are 0.918 and 0.959, 0.258 and 0.179, respectively. The prediction R 2 and RMSE of QSAR test sets by MLR model are 0.892 and 0.329, by SVM model are 0.958 and 0.234, respectively. The nonlinear model developed by SVM algorithm is much outperformed MLR, which indicates that SVM model is more reliable in the prediction of toxicity of ILs. This study shows that increasing the relative number of O atoms of molecules leads to decrease in the toxicity of ILs

Formation of crystalline telluridomercurates from ionic liquids near room temperature

Energy Technology Data Exchange (ETDEWEB)

Donsbach, Carsten; Dehnen, Stefanie [Fachbereich Chemie und Wissenschaftliches Zentrum fuer Materialwissenschaften, Philipps-Universitaet Marburg, Hans-Meerwein-Strasse 4, 35043, Marburg (Germany)

2017-01-15

The ternary telluridomercurate Na{sub 2}[HgTe{sub 2}] (1) was formed by fusion of Na{sub 2}Te and HgTe at 600 C and further treated in the ionic liquid (C{sub 4}C{sub 1}Im)[BF{sub 4}] (C{sub 4}C{sub 1}Im = 1-butyl-3-methylimidazolium) at moderately elevated temperatures (60 C), leading to replacement of the Na{sup +} cations with (C{sub 4}C{sub 1}Im){sup +} and re-arrangement of the inorganic substructure. As a result, we obtained the telluridomercurate (C{sub 4}C{sub 1}Im){sub 2}[HgTe{sub 2}] (2) and the tellurido/ditelluridomercurate (C{sub 4}C{sub 1}Im){sub 2}[Hg{sub 2}Te{sub 4}] (3) besides polytellurides and HgTe as by-products. The heavy atom compositions of the compounds were confirmed by micro X-ray fluorescence spectroscopy (μ-XFS), and their structures were determined by single-crystal diffraction. The cation-exchanged salts were further investigated by UV/Vis spectroscopy, indicating narrow band-gap optical transitions at 2.80 eV (2) and 1.63 eV (3), in agreement with their visible yellow or reddish-black color, respectively. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Significant Improvement of Catalytic Efficiencies in Ionic Liquids

International Nuclear Information System (INIS)

Song, Choong Eui; Yoon, Mi Young; Choi, Doo Seong

2005-01-01

The use of ionic liquids as reaction media can confer many advantages upon catalytic reactions over reactions in organic solvents. In ionic liquids, catalysts having polar or ionic character can easily be immobilized without additional structural modification and thus the ionic solutions containing the catalyst can easily be separated from the reagents and reaction products, and then, be reused. More interestingly, switching from an organic solvent to an ionic liquid often results in a significant improvement in catalytic performance (e.g., rate acceleration, (enantio)selectivity improvement and an increase in catalyst stability). In this review, some recent interesting results which can nicely demonstrate these positive 'ionic liquid effect' on catalysis are discussed

Thermophysical properties of sulfonium- and ammonium-based ionic liquids.

Science.gov (United States)

Bhattacharjee, Arijit; Luís, Andreia; Lopes-da-Silva, José A; Freire, Mara G; Carvalho, Pedro J; Coutinho, João A P

2014-11-15

Experimental data for the density, viscosity, refractive index and surface tension of four sulfonium- and ammonium-based Ionic Liquids (ILs) with the common bis(trifluoromethylsulfonyl)imide anion were measured in the temperature range between 288.15 and 353.15 K and at atmospheric pressure. The ILs considered include butyltrimethylammonium bis(trifluoromethylsulfonyl)imide, [N 4111 ][NTf 2 ], tributylmethylammonium bis(trifluoromethylsulfonyl)imide, [N 4441 ][NTf 2 ], diethylmethylsulfonium bis(trifluoromethylsulfonyl)imide, [S 221 ][NTf 2 ], and triethylsulfonium bis(trifluoromethylsulfonyl)imide, [S 222 ][NTf 2 ]. Based on the gathered results and on data taken from literature, the impact of the cation isomerism and of the size of the aliphatic tails, as well as the effect resulting from the substitution of a nitrogen by a sulfur atom as the cation central atom, on the thermophysical properties of sulfonium- and ammonium-based ILs is here discussed. Remarkably, more symmetric cations present a lower viscosity for the same, and sometimes even for higher, alkyl chain lengths at the cation. Additional derivative properties, such as the isobaric thermal expansion coefficient, the surface thermodynamic properties and the critical temperature for the investigated ILs were also estimated and are presented and discussed.

Geometry optimization method versus predictive ability in QSPR modeling for ionic liquids

Science.gov (United States)

Rybinska, Anna; Sosnowska, Anita; Barycki, Maciej; Puzyn, Tomasz

2016-02-01

Computational techniques, such as Quantitative Structure-Property Relationship (QSPR) modeling, are very useful in predicting physicochemical properties of various chemicals. Building QSPR models requires calculating molecular descriptors and the proper choice of the geometry optimization method, which will be dedicated to specific structure of tested compounds. Herein, we examine the influence of the ionic liquids' (ILs) geometry optimization methods on the predictive ability of QSPR models by comparing three models. The models were developed based on the same experimental data on density collected for 66 ionic liquids, but with employing molecular descriptors calculated from molecular geometries optimized at three different levels of the theory, namely: (1) semi-empirical (PM7), (2) ab initio (HF/6-311+G*) and (3) density functional theory (B3LYP/6-311+G*). The model in which the descriptors were calculated by using ab initio HF/6-311+G* method indicated the best predictivity capabilities ({{Q}}_{{EXT}}2 = 0.87). However, PM7-based model has comparable values of quality parameters ({{Q}}_{{EXT}}2 = 0.84). Obtained results indicate that semi-empirical methods (faster and less expensive regarding CPU time) can be successfully employed to geometry optimization in QSPR studies for ionic liquids.

Pulse radiolysis study on solvated electrons in ionic liquid with controlling water content

International Nuclear Information System (INIS)

Yang Jinfeng; Kondoh, T.; Yoshida, Y.; Nagaishi, R.

2006-01-01

content of 0 to 1.4 wt% in ionic liquid, i.e., changing the ionic liquid from the dehydrated state to the water-saturated state. It indicates that the solvation structure of electrons solvated with DEMMA cations was changed to be that hydrated with water molecules, as shown in Fig. 1. In the experiment, several solutes, including acetone, trivalent ion of europium (III), pyrene, and biphenyl, were used to study the reactions of the solvated electrons in ionic liquid. (authors)

Photoionization of excited atoms and ions: recent progress and future prospects

International Nuclear Information System (INIS)

Wuilleumier, F.J.

2004-01-01

Full text: Photoionization of atoms in the ground state using synchrotron radiation (SR) has contributed extensively to a better knowledge of atomic structure and of its dynamical response to photon interaction. Since the st use in 1963 of an SR facility in the ultraviolet to investigate autoionizing states in helium, each improvement in the performance of available SR beams has allowed to go deeper and deeper into the understanding of isolated atomic systems. The study of very dilute targets such as atoms prepared in selected excited states or multiply-charged ions is more challenging. Using dye lasers, the excited state can be prepared with a well defined set of quantum numbers and SR photoionization of this prepared state can be studied as a function of photon energy and emission-angle. For ions, the equivalent ionic densities achievable in a merged-beam experiment do not exceed, usually, 10 6 cm -3 , i.e. they are lower by 5 orders of magnitude than for atoms in the ground state. This explains why the response of ionized matter to photoionizing radiation has been largely unexplored until recently. Theoretical methods, still to be tested by experimental measurements, have been developed to model stellar atmospheres as well as laboratory plasmas. After the pioneering experiments using plasma discharge technology and laser-produced plasmas to measure photoionization in excited states and ions, the use of SR has allowed to dramatically improve experiments for excited- and ionic-species, starting with the first measurements of electron spectra from photoionization of laser-excited sodium atoms, and with the first determination of doubly-charged ion rate resulting from photoionization of singly-charged ions in merged beam experiments. Over the past 5 years, photoionization of singly- and multiply-charged ions using the merged beam technique has been intensively performed at four SR facilities (ASTRID, Spring-8, the Advanced Light Source (ALS), and Super-ACO), all of

Continuous 25-yr aerosol records at coastal Antarctica - I: inter-annual variability of ionic compounds and links to climate indices

Energy Technology Data Exchange (ETDEWEB)

Weller, Rolf; Koenig-Langlo, Gert (Alfred Wegener Inst. for Polar and Marine Research, Bremerhaven (Germany)), e-mail: Rolf.Weller@awi.de; Wagenbach, Dietmar; Elsaesser, Christoph (Institut fur Umweltphysik, Univ. of Heidelberg, Heidelberg (Germany)); Legrand, Michel (Laboratoire de Glaciologie et Geophysique de l' Environnement du Centre National de la Recherche Scientifique, St Martin d' Heres (France)); Tian-Kunze, Xiangshan (Institut fur Meereskunde, Univ. of Hamburg, Hamburg (Germany))

2011-11-15

The aerosol climatology at the coastal Antarctic Neumayer Station (NM) was investigated based on continuous, 25-yr long observations of biogenic sulphur components (methanesulfonate and non-sea salt sulphate), sea salt and nitrate. Although significant long-term trends could only be detected for nitrate (-3.6 +- 2.5% per year between 1983 and 1993 and +4.0 +- 3.2% per year from 1993-2007), non-harmonic periodicities between 2 and 5 yr were typical for all species. Dedicated time series analyses revealed that relations to sea ice extent and various circulation indices are weak at best or not significant. In particular, no consistent link between sea ice extent and sea salt loadings was evident suggesting only a rather local relevance of the NM sea salt record. Nevertheless, a higher Southern Annular Mode index tended to entail a lower biogenic sulphur signal. In examining the spatial uniformity of the NM findings we contrasted them to respective 17 yr records from the coastal Dumont d'Urville Station. We found similar long-term trends for nitrate, indicating an Antarctic-wide but not identifiable atmospheric signal, although any significant impact of solar activity or pollution could be ruled out. No inter-site variability on the multiannual scale was evident for the other ionic compounds

Atomic scale imaging of structural changes in solid electrolyte lanthanum lithium niobate upon annealing

International Nuclear Information System (INIS)

Hu, Xiaobing; Fisher, Craig A.J.; Kobayashi, Shunsuke; Ikuhara, Yumi H.; Fujiwara, Yasuyuki; Hoshikawa, Keigo; Moriwake, Hiroki; Kohama, Keiichi; Iba, Hideki; Ikuhara, Yuichi

2017-01-01

La (1-x)/3 Li x NbO 3 (LLNbO) is a promising electrolyte material for solid-state lithium-ion batteries because it is stable in contact with Li metal and contains a high concentration of intrinsic Li-ion vacancies. One strategy for improving its ionic conductivity and making it more competitive with other solid-state Li-ion electrolytes is to disorder the Li-ion vacancies by appropriate post-synthesis heat treatment, e.g., annealing. In this study, we examine the effects of annealing on single crystals of LLNbO with Li contents x = 0.07 and 0.13 based on simultaneous atomic resolution high angle annular dark field and annular bright field imaging methods using state-of-the-art aberration corrected scanning transmission electron microscopes. It is found that La modulation within A1 layers of the cation-deficient layered perovskite structure becomes more diffuse after annealing. In addition, some La atoms move to A-site positions and O4 window positions in the nominally vacant A2 layer, while O atom columns in this layer become rumpled in the [001] p direction, indicating that the NbO 6 octahedra are more heavily distorted after annealing. The observed crystal structure differences between as-prepared and annealed single crystals explain the drop in Li-ion conductivities of LLNbO single crystals after heat treatment.

Inelastic tunneling spectroscopy for magnetic atoms and the Kondo resonance

International Nuclear Information System (INIS)

Goldberg, E C; Flores, F

2013-01-01

The interaction between a single magnetic atom and the metal environment (including a magnetic field) is analyzed by introducing an ionic Hamiltonian combined with an effective crystal-field term, and by using a Green-function equation of motion method. This approach describes the inelastic electron tunneling spectroscopy and the Kondo resonances as due to atomic spin fluctuations associated with electron co-tunneling processes between the leads and the atom. We analyze in the case of Fe on CuN the possible spin fluctuations between states with S = 2 and 3/2 or 5/2 and conclude that the experimentally found asymmetries in the conductance with respect to the applied bias, and its marked structures, are well explained by the 2↔3/2 spin fluctuations. The case of Co is also considered and shown to present, in contrast with Fe, a resonance at the Fermi energy corresponding to a Kondo temperature of 6 K. (paper)

Evaluations of imidazolium ionic liquids as novel skin permeation enhancers for drug transdermal delivery.

Science.gov (United States)

Zhang, Ding; Wang, Huai-Ji; Cui, Xiu-Ming; Wang, Cheng-Xiao

2017-06-01

In this work, imidazolium ionic liquids (imidazolium ILs) were employed as the novel chemical permeation enhancers (CPEs) and their performances and mechanisms of action were deeply investigated. Testosterone was used as a model drug to investigate the transdermal delivery enhancement of twenty imdidazolium ILs. The results suggested that the promotion activity connected to the structure and composition of the ILs. The quantitative structure-activity relationship (QSAR) model revealed a good linearity between the electronic properties of ILs and their enhancements. Furthermore, the transepidermal water loss (TEWL) and scanning laser confocal microscope (CLSM) examinations showed the strong improvement of ILs on skin barrier permeability, which were well correlated with the drug penetration profiles. The total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) and atomic force microscope (AFM) evaluations of skins indicated that the ILs can disrupt the regular and compact arrangements of the corneocytes, change the surface properties of stratum corneum, and make the skin structure more permeable. Our work demonstrated the significant skin permeation promotion profiles of the imidazolium ILs, which are of great potential in transdermal drug delivery systems.

Study of thermodynamic and transport properties of phosphonium-based ionic liquids

International Nuclear Information System (INIS)

Deive, Francisco J.; Rivas, Miguel A.; Rodríguez, Ana

2013-01-01

Highlights: ► Physical and transport properties of three hydrophilic phoshonium ILs were determined. ► Experimental density, viscosity, refractive index and speed of sound were correlated. ► Predictive equations were successfully employed to predict density of the three ILs. -- Abstract: In this work, the experimental values of density, speed of sound, refractive index and dynamic viscosity have been obtained from T = (293.15 to 343.15) K for the three phosphonium-based ionic liquids: tributyl methyl phoshponium methylsulfate (P 4441 C 1 SO 4 ), tributyl ethyl phosphonium diethylphosphate (P 4442 (C 2 ) 2 PO 4 ) and tributyl octyl phosphonium chloride (P 4448 Cl). The isentropic compressibility has been calculated by means of the Laplace equation from the experimental speed of sound results for the three ionic liquids at different temperatures. Density, speed of sound, refractive index and isentropic compressibility have been correlated by polynomial equations. The Lorentz–Lorenz, Dale–Gladstone, Eykman, Oster, Arago–Biot, Newton and modified Eykman equations were the empirical models used to correlate satisfactorily the relationship between the densities and refractive indices of the ionic liquids selected. The temperature dependence of the experimental dynamic viscosities for the ionic liquids selected can be described by an Arrhenius-like law and by VFT equations. The Riedel, Narsimham, Bradford–Thodos, Yen–Woods, Rackett, Spencer–Danner, Gunn–Yamada, Hankinson–Thomson (COSTALD model), VSY, VSD, MH and LGM equations were employed to predict the densities of the pure ionic liquids

An Efficient Process for Pretreatment of Lignocelluloses in Functional Ionic Liquids

Directory of Open Access Journals (Sweden)

Shi-Jia Dong

2015-01-01

Full Text Available Background and Aims. The complex structure of the lignocelluloses is the main obstacle in the conversion of lignocellulosic biomass into valuable products. Ionic liquids provide the opportunities for their efficient pretreatment for biomass. Therefore, in this work, pretreatment of corn stalk was carried out in ultrasonic-assisted ionic liquid including 1-butyl-3-methylimidazolium chloride [BMIM]Cl, 1-H-3-methylimidazolium chloride [HMIM]Cl, and 1-(1-propylsulfonic-3-imidazolium chloride [HSO3-pMIM]Cl at 70°C for 2 h. We compared the pretreatments by ionic liquid with and without the addition of deionized water. Fourier transform infrared spectroscopy (FTIR and scanning electron microscopy (SEM were employed to analyze the chemical characteristics of regenerated cellulose-rich materials. Results. [HMIM]Cl and [HSO3-pMIM]Cl were effective in lignin extraction to obtain cellulose-rich materials. FTIR analysis and SEM analysis indicated the effective lignin removal and the reduced crystallinity of cellulose-rich materials. Enzymatic hydrolysis of cellulose-rich materials was performed efficiently. High yields of reducing sugar and glucose were obtained when the corn stalk was pretreated by [HMIM]Cl and [HSO3-pMIM]Cl. Conclusions. Ionic liquids provided the ideal environment for lignin extraction and enzymatic hydrolysis of corn stalk and [HMIM]Cl and [HSO3-pMIM]Cl proved the most efficient ionic liquids. This simple and environmentally acceptable method has a great potential for the preparation of bioethanol for industrial production.

Many-electron electrochemical processes. Reactions in molten salts, room-temperature ionic liquids and ionic solutions

Energy Technology Data Exchange (ETDEWEB)

Andriiko, Aleksandr A. [National Technical Univ. Ukraine, Kyiv (Ukraine). Kyiv Polytechnic Inst.; Andriyko, Yuriy O. [CEST Centre of Electrochemical Surface Technology, Wiener Neustadt (Austria); Nauer, Gerhard E. [Vienna Univ. (Austria). Inst. of Physical Chemistry

2013-02-01

The authors provide a unified concept for understanding multi-electron processes in electrochemical systems such as molten salts, ionic liquids, or ionic solutions. A major advantage of this concept is its independence of assumptions like one-step many-electron transfers or 'discrete' discharge of complex species. This book contains the following main topics: 1. Many-electron electrochemical systems: Concepts and definitions. 2. Many-electron systems at equilibrium. 3. Phenomenology of electrochemical kinetics. 4. Electrode film systems: experimental evidences. 5. Dynamics of a non-equilibrium electrochemical system. 6. Electrochemistry of Ti(IV) in ionic liquids.

Salt-assisted liquid-liquid microextraction of Cr(VI) ion using an ionic liquid for preconcentration prior to its determination by flame atomic absorption spectrometry

International Nuclear Information System (INIS)

Majidi, B.; Shemirani, F.

2012-01-01

We report on the salt-assisted liquid-liquid microextraction of cationic complexes of Cr(VI) ion using the hydrophilic ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoraborate and potassium hydrogen phosphate. This is a novel, simple, non-toxic and effective technique for sample pretreatment technique that displays large extraction efficiency and represents a new platform where Cr(VI) is complexed with 1,5-diphenylcarbazide (DPC) in sulfuric acid medium. It was applied to the extraction of Cr(VI) in the form of the Cr(VI)-DPC complex prior to its determination by flame atomic absorption spectrometry. Cr(III) ion also can be determined by this procedure after oxidation to Cr(VI). Extraction is mainly affected by the amount of water-soluble IL, the kind and quantity of inorganic salts, by pH and the concentration of DPC. Calibration plots are linear in the range from 3 to 150 μg L -1 of Cr(VI), and the limit of detection is 1. 25 μg L -1 . The method was successfully applied to the speciation and determination of trace levels of Cr(III) and Cr(VI) in environmental water samples containing high levels of dissolved salts or food grade salts. (author)

Magnetic stirrer induced dispersive ionic-liquid microextraction for the determination of vanadium in water and food samples prior to graphite furnace atomic absorption spectrometry.

Science.gov (United States)

Naeemullah; Kazi, Tasneem Gul; Tuzen, Mustafa

2015-04-01

A new dispersive liquid-liquid microextraction, magnetic stirrer induced dispersive ionic-liquid microextraction (MS-IL-DLLME) was developed to quantify the trace level of vanadium in real water and food samples by graphite furnace atomic absorption spectrometry (GFAAS). In this extraction method magnetic stirrer was applied to obtained a dispersive medium of 1-butyl-3-methylimidazolium hexafluorophosphate [C4MIM][PF6] in aqueous solution of (real water samples and digested food samples) to increase phase transfer ratio, which significantly enhance the recovery of vanadium - 4-(2-pyridylazo) resorcinol (PAR) chelate. Variables having vital role on desired microextraction methods were optimised to obtain the maximum recovery of study analyte. Under the optimised experimental variables, enhancement factor (EF) and limit of detection (LOD) were achieved to be 125 and 18 ng L(-1), respectively. Validity and accuracy of the desired method was checked by analysis of certified reference materials (SLRS-4 Riverine water and NIST SRM 1515 Apple leaves). The relative standard deviation (RSD) for 10 replicate determinations at 0.5 μg L(-1) of vanadium level was found to be <5.0%. This method was successfully applied to real water and acid digested food samples. Copyright © 2014 Elsevier Ltd. All rights reserved.

Lithium-conducting ionic melt electrolytes from polyether-functionalized fluorosulfonimide anions

International Nuclear Information System (INIS)

Hallac, B.B.; Geiculescu, O.E.; Rajagopal, R.V.; Creager, S.E.; DesMarteau, D.D.

2008-01-01

Solvent-free lithium-conducting ionic melt (IM) electrolytes were synthesized and characterized with respect to chemical structure, purity, and ion transport properties. The melts consist of lithium (perfluorovinylether)sulfonimide salts attached covalently to a lithium-solvating polyether chain. Ionic conductivities are relatively high which is a consequence of the favorable combination of the low lattice energy of the lithium fluorosulfonimide salt (low basicity of the fluorosulfonimide anion), the relatively low viscosity of the polyether matrix, and the relatively high salt content of the melts. Galvanostatic dc polarization experiments, using cells with non-blocking Li electrodes, indicate that salt concentration polarization does not occur in these electrolytes as dc current is passed through them

Impurity effects on ionic-liquid-based supercapacitors

International Nuclear Information System (INIS)

Liu, Kun; Lian, Cheng; Henderson, Douglas; Wu, Jianzhong

2016-01-01

Small amounts of an impurity may affect the key properties of an ionic liquid and such effects can be dramatically amplified when the electrolyte is under confinement. Here the classical density functional theory is employed to investigate the impurity effects on the microscopic structure and the performance of ionic-liquid-based electrical double-layer capacitors, also known as supercapacitors. Using a primitive model for ionic species, we study the effects of an impurity on the double layer structure and the integral capacitance of a room temperature ionic liquid in model electrode pores and find that an impurity strongly binding to the surface of a porous electrode can significantly alter the electric double layer structure and dampen the oscillatory dependence of the capacitance with the pore size of the electrode. Meanwhile, a strong affinity of the impurity with the ionic species affects the dependence of the integral capacitance on the pore size. Up to 30% increase in the integral capacitance can be achieved even at a very low impurity bulk concentration. As a result, by comparing with an ionic liquid mixture containing modified ionic species, we find that the cooperative effect of the bounded impurities is mainly responsible for the significant enhancement of the supercapacitor performance.

Ionic-Liquid-Infused Nanostructures as Repellent Surfaces.

Science.gov (United States)

Galvan, Yaraset; Phillips, Katherine R; Haumann, Marco; Wasserscheid, Peter; Zarraga, Ramon; Vogel, Nicolas

2018-02-02

In order to prepare lubricant-infused repellent coatings on silica nanostructures using low vapor pressure ionic liquids as lubricants, we study the wetting behavior of a set of imidazolium-based ionic liquids with different alkyl side chains as a function of the applied surface functionalities. We take advantage of the structural color of inverse opals prepared from a colloidal coassembly technique to study the infiltration of ionic liquids into these nanoporous structures. We find that the more hydrophobic ionic liquids with butyl and hexyl side chains can completely infiltrate inverse opals functionalized with mixed self-assembled monolayers composed of imidazole groups and aliphatic hydrocarbon chains, which we introduce via silane chemistry. These molecular species reflect the chemical nature of the ionic liquid, thereby increasing the affinity between the liquid and solid surface. The mixed surface chemistry provides sufficiently small contact angles with the ionic liquid to infiltrate the nanopores while maximizing the contact angle with water. As a result, the mixed monolayers enable the design of a stable ionic liquid/solid interface that is able to repel water as a test liquid. Our results underline the importance of matching chemical affinities to predict and control the wetting behavior in complex, multiphase systems.

Impurity effects on ionic-liquid-based supercapacitors

Science.gov (United States)

Liu, Kun; Lian, Cheng; Henderson, Douglas; Wu, Jianzhong

2017-02-01

Small amounts of an impurity may affect the key properties of an ionic liquid and such effects can be dramatically amplified when the electrolyte is under confinement. Here the classical density functional theory is employed to investigate the impurity effects on the microscopic structure and the performance of ionic-liquid-based electrical double-layer capacitors, also known as supercapacitors. Using a primitive model for ionic species, we study the effects of an impurity on the double layer structure and the integral capacitance of a room temperature ionic liquid in model electrode pores and find that an impurity strongly binding to the surface of a porous electrode can significantly alter the electric double layer structure and dampen the oscillatory dependence of the capacitance with the pore size of the electrode. Meanwhile, a strong affinity of the impurity with the ionic species affects the dependence of the integral capacitance on the pore size. Up to 30% increase in the integral capacitance can be achieved even at a very low impurity bulk concentration. By comparing with an ionic liquid mixture containing modified ionic species, we find that the cooperative effect of the bounded impurities is mainly responsible for the significant enhancement of the supercapacitor performance.

[Advances of poly (ionic liquid) materials in separation science].

Science.gov (United States)

Liu, Cuicui; Guo, Ting; Su, Rina; Gu, Yuchen; Deng, Qiliang

2015-11-01

Ionic liquids, as novel ionization reagents, possess beneficial characteristics including good solubility, conductivity, thermal stability, biocompatibility, low volatility and non-flammability. Ionic liquids are attracting a mass of attention of analytical chemists. Poly (ionic liquid) materials have common performances of ionic liquids and polymers, and have been successfully applied in separation science area. In this paper, we discuss the interaction mechanisms between the poly(ionic liquid) materials and analytes including hydrophobic/hydrophilic interactions, hydrogen bond, ion exchange, π-π stacking and electrostatic interactions, and summarize the application advances of the poly(ionic liquid) materials in solid phase extraction, chromatographic separation and capillary electrophoresis. At last, we describe the future prospect of poly(ionic liquid) materials.

Basic studies of atomic dynamics. Progress report, September 1, 1981-June 30, 1982

International Nuclear Information System (INIS)

Fano, U.

1982-01-01

The theory of the Stark effect of atoms other than hydrogen has been completed with successful fit to high resolution experiments near the ionization threshold. Extensive but highly fragmentary evidence on resonant states of a single Rydberg electron in a magnetic field and a pair of electrons in an ionic field has been analyzed producing a unified composite picture. New developments in Quantum Defect Theory are outlined

Determination of Europium by fluorescence using pyrrolidinium based task specific ionic liquid

International Nuclear Information System (INIS)

Kumar, Satendra; Gayan, Siuli Maji; Sankaran, K.

2012-01-01

Determination of lanthanides using fluorescence is a major challenge in aqueous medium due to their poor molar absorptivities and low quantum yield. To overcome these problems, ligand sensitized fluorescence has been widely used for trace level detection of lanthanides in solutions. Recently, ionic liquid a non aqueous medium has been used to observe the fluorescence of lanthanides. In this work we have used pyrrolidinium based ionic liquid for the study of europium fluorescence. The ionic liquid (bmpyr)(BA) was prepared using the metathesis reaction involving 1-butyl,1-methyl pyrrolidinium chloride (bmpyr)(CI). (bmpyr)(Cl) crystals and silver benzoate were added according to their mole equivalents in methanol and stirred for 4 hrs. The filtrate was concentrated using a rotary evaporator, dried for 10 h at room temperature, and then for 40 h at 105℃under reduced pressure. This results in a white crystalline hygroscopic solid which was characterized by FT-lR spectroscopy. The yield of the product was ∼ 95%. Butyl-1, methyl pyrrolidinium bis(trifluoromethanesulfonyl)amide (bmpyr)(TF 2 N) is used for dissolve and dilute (bmpyr)(BA) and fluorescence and life time of Eu 3+ were obtained. For the concentration of Eu 3+ used in this study (2x10 -7 M), the optimum concentration of the sensitizing ionic liquid was found to be 10 -4 M. An enhancement factor of about 32000 was found in this ionic liquid compare to aqueous medium. Fluorescence life time of europium in this ionic liquid is 1100 μs which is ten times more than the life time of europium in aqueous medium (110 μs), indicating a reduction in the rates of non-radiative processes which was provided by the ionic liquid. This study leads to detection of europium in ppb level. (author)

Tribological properties of self-assembled monolayers of catecholic imidazolium and the spin-coated films of ionic liquids.

Science.gov (United States)

Liu, Jianxi; Li, Jinlong; Yu, Bo; Ma, Baodong; Zhu, Yangwen; Song, Xinwang; Cao, Xulong; Yang, Wu; Zhou, Feng

2011-09-20

A novel compound of an imidazolium type of ionic liquid (IL) containing a biomimetic catecholic functional group normally seen in mussel adhesive proteins was synthesized. The IL can be immobilized on a silicon surface and a variety of other engineering material surfaces via the catecholic anchor, allowing the tribological protection of these substrates for engineering applications. The surface wetting and adhesive properties and the tribological property of the synthesized self-assembled monolayers (SAMs) are successfully modulated by altering the counteranions. The chemical composition and wettability of the IL SAMs were characterized by means of X-ray photoelectron spectroscopy (XPS) and contact angle (CA) measurements. The adhesive and friction forces were measured with an atomic force microscope (AFM) on the nanometer scale. IL composite films were prepared by spin coating thin IL films on top of the SAMs. The macrotribological properties of these IL composite films were investigated with a pin-on-disk tribometer. The results indicate that the presence of IL SAMs on a surface can improve the wettability of spin-coated ionic liquids and thus the film quality and the tribological properties. These films registered a reduced friction coefficient and a significantly enhanced durability and load-carrying capacity. The tribological properties of the composite films are better than those of pure IL films because the presence of the monolayers improves the adhesion and compatibility of spin-coated IL films with substrates. © 2011 American Chemical Society

Interaction of copper with dinitrogen tetroxide in 1-butyl-3-methylimidazolium-based ionic liquids.

Science.gov (United States)

Morozov, I V; Deeva, E B; Glazunova, T Yu; Troyanov, S I; Guseinov, F I; Kustov, L M

2017-03-27

Ionic liquids that are stable toward oxidation and nitration and are based on the 1-n-butyl-3-methylimidazolium cation (BMIm + ) can be used as solvents and reaction media for copper dissolution in liquid dinitrogen tetraoxide N 2 O 4 . The ionic liquid not only favors the dissociation of N 2 O 4 into NO + and NO 3 - , but also takes part in the formation of different crystalline products. Thus, NO[BF 4 ], NO[Cu(NO 3 ) 3 ] and (BMIm) 2 [Cu 2 (CF 3 COO) 6 ] were prepared using (BMIm)A, A - = [BF 4 ] - , (CF 3 SO 2 ) 2 N - , CF 3 COO - , respectively. The formation of a certain product is determined by the nature of the anion A - and the relative solubility of the reaction products in the ionic liquid. Crystals of NO[BF 4 ] were also prepared directly from a mixture of N 2 O 4 and BMImBF 4 . According to XRD single-crystal structure analysis, the structure of NO[BF 4 ] consists of tetrahedral [BF 4 ] - anions and nitrosonium NO + cations; the formation of these ions prove the heterolytic dissociation of N 2 O 4 dissolved in the ionic liquid. The crystal structure of the earlier unknown binuclear copper trifluoroacetate (BMIm) 2 [Cu 2 (CF 3 COO) 6 ] were determined by X-ray diffraction. The peculiarity of this dimer compared to the majority of known dimeric copper(ii) carboxylates is the unusually long CuCu distance (3.15 Å), with Cu(ii) ions demonstrating an atypical coordination of a distorted trigonal bipyramid formed by five O atoms of five trifluoroacetate groups.

Ionic liquid-assisted multiwalled carbon nanotube-dispersive micro-solid phase extraction for sensitive determination of inorganic As species in garlic samples by electrothermal atomic absorption spectrometry

Energy Technology Data Exchange (ETDEWEB)

Grijalba, Alexander Castro; Escudero, Leticia B.; Wuilloud, Rodolfo G., E-mail: rwuilloud@mendoza-conicet.gob.ar

2015-08-01

A highly sensitive dispersive micro-solid phase extraction (D-μ-SPE) method combining an ionic liquid (IL) and multi-walled carbon nanotubes (MWCNTs) for inorganic As species (As(III) and As(V)) species separation and determination in garlic samples by electrothermal atomic absorption spectrometry (ETAAS) was developed. Trihexyl(tetradecil)phosphonium chloride IL was used to form an ion pair with the arsenomolybdate complex obtained by reaction of As(V) with molybdate ion. Afterwards, 1.0 mg of MWCNTs was dispersed for As(V) extraction and the supernatant was separated by centrifugation. MWCNTs were re-dispersed with tetradecyltrimethylammonium bromide surfactant and ultrasound followed by direct injection into the graphite furnace of ETAAS for As determination. Pyrolysis and atomization conditions were carefully studied for complete decomposition of MWCNTs and IL matrices. Under optimum conditions, an extraction efficiency of 100% and a preconcentration factor of 70 were obtained with 5 mL of garlic extract. The detection limit was 7.1 ng L{sup −1} and the relative standard deviations (RSDs) for six replicate measurements at 5 μg L{sup −1} of As were 5.4% and 4.8% for As(III) and As(V), respectively. The proposed D-μ-SPE method allowed the efficient separation and determination of inorganic As species in a complex matrix such as garlic extract. - Highlights: • Efficient retention and preconcentration of As by combining an IL with MWCNTs • Determination of As by ETAAS with direct injection of MWCNTs • Thermal degradation of MWCNTs in the graphite furnace of ETAAS • Highly sensitive speciation and determination of As in garlic.

Ionic liquid-assisted multiwalled carbon nanotube-dispersive micro-solid phase extraction for sensitive determination of inorganic As species in garlic samples by electrothermal atomic absorption spectrometry

International Nuclear Information System (INIS)

Grijalba, Alexander Castro; Escudero, Leticia B.; Wuilloud, Rodolfo G.

2015-01-01

A highly sensitive dispersive micro-solid phase extraction (D-μ-SPE) method combining an ionic liquid (IL) and multi-walled carbon nanotubes (MWCNTs) for inorganic As species (As(III) and As(V)) species separation and determination in garlic samples by electrothermal atomic absorption spectrometry (ETAAS) was developed. Trihexyl(tetradecil)phosphonium chloride IL was used to form an ion pair with the arsenomolybdate complex obtained by reaction of As(V) with molybdate ion. Afterwards, 1.0 mg of MWCNTs was dispersed for As(V) extraction and the supernatant was separated by centrifugation. MWCNTs were re-dispersed with tetradecyltrimethylammonium bromide surfactant and ultrasound followed by direct injection into the graphite furnace of ETAAS for As determination. Pyrolysis and atomization conditions were carefully studied for complete decomposition of MWCNTs and IL matrices. Under optimum conditions, an extraction efficiency of 100% and a preconcentration factor of 70 were obtained with 5 mL of garlic extract. The detection limit was 7.1 ng L −1 and the relative standard deviations (RSDs) for six replicate measurements at 5 μg L −1 of As were 5.4% and 4.8% for As(III) and As(V), respectively. The proposed D-μ-SPE method allowed the efficient separation and determination of inorganic As species in a complex matrix such as garlic extract. - Highlights: • Efficient retention and preconcentration of As by combining an IL with MWCNTs • Determination of As by ETAAS with direct injection of MWCNTs • Thermal degradation of MWCNTs in the graphite furnace of ETAAS • Highly sensitive speciation and determination of As in garlic

Ionic liquids comprising heteraromatic anions

Energy Technology Data Exchange (ETDEWEB)

Schneider, William F.; Brennecke, Joan F.; Maginn, Edward J.; Mindrup, Elaine; Gurkan, Burcu; Price, Erica; Goodrich, Brett

2018-04-24

Some embodiments described herein relate to ionic liquids comprising an anion of a heteraromatic compound such as optionally substituted pyrrolide, optionally substituted pyrazolide, optionally substituted indolide, optionally substituted phospholide, or optionally substituted imidazolide. Methods and devices for gas separation or gas absorption related to these ionic liquids are also described herein.

Lewis Acidic Ionic Liquids.

Science.gov (United States)

Brown, Lucy C; Hogg, James M; Swadźba-Kwaśny, Małgorzata

2017-08-21

Until very recently, the term Lewis acidic ionic liquids (ILs) was nearly synonymous with halometallate ILs, with a strong focus on chloroaluminate(III) systems. The first part of this review covers the historical context in which these were developed, speciation of a range of halometallate ionic liquids, attempts to quantify their Lewis acidity, and selected recent applications: in industrial alkylation processes, in supported systems (SILPs/SCILLs) and in inorganic synthesis. In the last decade, interesting alternatives to halometallate ILs have emerged, which can be divided into two sub-sections: (1) liquid coordination complexes (LCCs), still based on halometallate species, but less expensive and more diverse than halometallate ionic liquids, and (2) ILs with main-group Lewis acidic cations. The two following sections cover these new liquid Lewis acids, also highlighting speciation studies, Lewis acidity measurements, and applications.

The 1-ethyl-3-methylimidazolium bis(trifluoro-methylsulfonyl)-imide ionic liquid nanodroplets on solid surfaces and in electric field: A molecular dynamics simulation study

Science.gov (United States)

Dong, Dengpan; Vatamanu, Jenel P.; Wei, Xiaoyu; Bedrov, Dmitry

2018-05-01

Atomistic molecular dynamics simulations were conducted to study the wetting states of 1-ethyl-3-methylimidazolium bis(trifluoro-methylsulfonyl)-imide ionic liquid (IL) nanodroplets on surfaces with different strengths of van der Waals (VDW) interactions and in the presence of an electric field. By adjusting the depth of Lennard-Jones potential, the van der Waals interaction between the solid surface and ionic liquid was systematically varied. The shape of the droplets was analyzed to extract the corresponding contact angle utilized to characterize wetting states of the nanodroplets. The explored range of surface-IL interactions allowed contact angles ranging from complete IL spreading on the surface to poor wettability. The effect of the external electrical field was explored by adding point charges to the surface atoms. Systems with two charge densities (±0.002 e/atom and ±0.004 e/atom) that correspond to 1.36 V/nm and 2.72 V/nm electric fields were investigated. Asymmetrical wetting states were observed for both cases. At 1.36 V/nm electric field, contributions of IL-surface VDW interactions and Coulombic interactions to the wetting state were competitive. At 2.72 V/nm field, electrostatic interactions dominate the interaction between the nanodroplet and surface, leading to enhanced wettability on all surfaces.

Specific ionic effect for simple and rapid colorimetric sensing assays of amino acids using gold nanoparticles modified with task-specific ionic liquid

International Nuclear Information System (INIS)

Wu, Datong; Cai, Pengfei; Tao, Zhihao; Pan, Yuanjiang

2016-01-01

In this study, a novel task-specific ionic liquid functionalized gold nanoparticle (TSIL-GNP) was successfully prepared and applied in the recognition of amino acids. Particularly, the surface of GNP was modified with the ionic liquid containing carbamido and ester group via thiol, which was characterized by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The stability of this material in aqueous solution improves apparently and can remain unchanged for more than three months. The effect of pH was also discussed in this study. Attractive ionic interaction would effectively weaken intensity of the covalent coupling between the metal ion and the functional groups of amino acids. Thus, TSIL-GNP was successfully applied to recognizing serine, aspartic acid, lysine, arginine, and histidine in the presence of Cu"2"+ through distinctive color changes. Suspension would be generated once a spot of cysteine was added into the GNPs solution. Results indicated that it had a good linear relationship between extinction coefficients and concentration of amino acids in a wide range of 10"−"3–10"−"6 M. Moreover, the proposed strategy was successfully used to analyze the histidine in urinary samples. In brief, TSIL-GNP is a suitable substrate for discrimination of five amino acids in a rapid and simple way without sophisticated instruments. - Highlights: • A novel task-specific ionic liquid functionalized gold nanoparticle was successfully prepared. • This material was successfully applied to recognizing five amino acids with Cu(II) through distinctive color changes. • The proposed strategy was successfully used to analyze the histidine in real samples.

Key Developments in Ionic Liquid Crystals

OpenAIRE

Fernandez, A.A.; Kouwer, P.H.J.

2016-01-01

Ionic liquid crystals are materials that combine the classes of liquid crystals and ionic liquids. The first one is based on the multi-billion-dollar flat panel display industry, whilst the latter quickly developed in the past decades into a family of highly-tunable non-volatile solvents. The combination yields materials with a unique set of properties, but also with many challenges ahead. In this review, we provide an overview of the key concepts in ionic liquid crystals, particularly from a...

Magnetomotive room temperature dicationic ionic liquid: a new concept toward centrifuge-less dispersive liquid-liquid microextraction.

Science.gov (United States)

Beiraghi, Asadollah; Shokri, Masood; Seidi, Shahram; Godajdar, Bijan Mombani

2015-01-09

A new centrifuge-less dispersive liquid-liquid microextraction technique based on application of magnetomotive room temperature dicationic ionic liquid followed by electrothermal atomic absorption spectrometry (ETAAS) was developed for preconcentration and determination of trace amount of gold and silver in water and ore samples, for the first time. Magnetic ionic liquids not only have the excellent properties of ionic liquids but also exhibit strong response to an external magnetic field. These properties provide more advantages and potential application prospects for magnetic ionic liquids than conventional ones in the fields of extraction processes. In this work, thio-Michler's ketone (TMK) was used as chelating agent to form Ag/Au-TMK complexes. Several important factors affecting extraction efficiency including extraction time, rate of vortex agitator, pH of sample solution, concentration of the chelating agent, volume of ionic liquid as well as effects of interfering species were investigated and optimized. Under the optimal conditions, the limits of detection (LOD) were 3.2 and 7.3ngL(-1) with the preconcentration factors of 245 and 240 for Au and Ag, respectively. The precision values (RSD%, n=7) were 5.3% and 5.8% at the concentration level of 0.05μgL(-1) for Au and Ag, respectively. The relative recoveries for the spiked samples were in the acceptable range of 96-104.5%. The results demonstrated that except Hg(2+), no remarkable interferences are created by other various ions in the determination of Au and Ag, so that the tolerance limits (WIon/WAu or Ag) of major cations and anions were in the range of 250-1000. The validated method was successfully applied for the analysis of Au and Ag in some water and ore samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Ionic channels underlying the ventricular action potential in zebrafish embryo.

Science.gov (United States)

Alday, Aintzane; Alonso, Hiart; Gallego, Monica; Urrutia, Janire; Letamendia, Ainhoa; Callol, Carles; Casis, Oscar

2014-06-01

Over the last years zebrafish has become a popular model in the study of cardiac physiology, pathology and pharmacology. Recently, the application of the 3Rs regulation and the characteristics of the embryo have reduced the use of adult zebrafish use in many studies. However, the zebrafish embryo cardiac physiology is poorly characterized since most works have used indirect techniques and direct recordings of cardiac action potential and ionic currents are scarce. In order to optimize the zebrafish embryo model, we used electrophysiological, pharmacological and immunofluorescence tools to identify the characteristics and the ionic channels involved in the ventricular action potentials of zebrafish embryos. The application of Na(+) or T-type Ca(+2) channel blockers eliminated the cardiac electrical activity, indicating that the action potential upstroke depends on Na(+) and T-type Ca(+2) currents. The plateau phase depends on L-type Ca(+2) channels since it is abolished by specific blockade. The direct channel blockade indicates that the action potential repolarization and diastolic potential depends on ERG K(+) channels. The presence in the embryonic heart of the Nav1.5, Cav1.2, Cav3.2 and ERG channels was also confirmed by immunofluorescence, while the absence of effect of specific blockers and immunostaining indicate that two K(+) repolarizing currents present in human heart, Ito and IKs, are absent in the embryonic zebrafish heart. Our results describe the ionic channels present and its role in the zebrafish embryo heart and support the use of zebrafish embryos to study human diseases and their use for drug testing. Copyright © 2014 Elsevier Ltd. All rights reserved.

My views on physics and atomic physics, on science and human life

International Nuclear Information System (INIS)

Berenyi, Denes

1999-01-01

The modern physics research was started in the 16th century. From that time any knowledge on the natural processes is based on careful, systematic observation, experiment and measurement. The scope of atomic physics is very broad energetically from nano eV to GeV. From these experiments fundamental information can be obtained and the collision mechanism as well as details of atomic and ionic structure can be clarified. Science is a really special field of the human activity and culture. It is developing mainly with the help of the critique of its own results. Science produced in fact miraculous results but even then it is only one of the approaches to Reality in a broad meaning

Impact of doping on the ionic conductivity of ceria: A comprehensive model

KAUST Repository

Wang, Hao

2013-06-13

Doped ceria is considered as an electrolyte for solid oxide fuel cell applications. The introduction of dopants in the ceria lattice will affect its electronic structure and, in turn, its ionic conductivity. Simulation of these issues using density functional theory becomes complicated by the random distribution of the constituent atoms. Here we use the generalized gradient approximation with on-site Coulomb interaction in conjunction with the special quasirandom structures method to investigate 18.75% and 25% Y, Gd, Sm, Pr, and La doped ceria. The calculated lattice constants and O migration energies allow us to explain the behavior of the conductivity as obtained in experiments.

mu. -nucleon atoms

Energy Technology Data Exchange (ETDEWEB)

Dobretsov, Yu; Dolgoshein, B; Kirillov-Ugryumov, V

1980-12-01

The properties and formation are described of ..mu..-nucleon atoms, the Larmor method of muon spin precession is discussed and the experimental confirmation of the existence of ..mu..-nucleon atoms is shown. The prospects of their use are indicated.

Modeling electrokinetics in ionic liquids: General

Energy Technology Data Exchange (ETDEWEB)

Wang, Chao [Physical and Computational Science Directorate, Pacific Northwest National Laboratory, Richland WA USA; Bao, Jie [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland WA USA; Pan, Wenxiao [Department of Mechanical Engineering, University of Wisconsin-Madison, Madison WI USA; Sun, Xin [Physical and Computational Science Directorate, Pacific Northwest National Laboratory, Richland WA USA

2017-04-07

Using direct numerical simulations we provide a thorough study on the electrokinetics of ionic liquids. In particular, the modfied Poisson-Nernst-Planck (MPNP) equations are solved to capture the crowding and overscreening effects that are the characteristics of an ionic liquid. For modeling electrokinetic flows in an ionic liquid, the MPNP equations are coupled with the Navier-Stokes equations to study the coupling of ion transport, hydrodynamics, and electrostatic forces. Specifically, we consider the ion transport between two parallel plates, charging dynamics in a 2D straight-walled pore, electro-osmotic ow in a nano-channel, electroconvective instability on a plane ion-selective surface, and electroconvective ow on a curved ion-selective surface. We discuss how the crowding and overscreening effects and their interplay affect the electrokinetic behaviors of ionic liquids in these application problems.

Applications of ionic liquids in polymer science and technology

CERN Document Server

2015-01-01

This book summarizes the latest knowledge in the science and technology of ionic liquids and polymers in different areas. Ionic liquids (IL) are actively being investigated in polymer science and technology for a number of different applications. In the first part of the book the authors present the particular properties of ionic liquids as speciality solvents. The state-of-the art in the use of ionic liquids in polymer synthesis and modification reactions including polymer recycling is outlined. The second part focuses on the use of ionic liquids as speciality additives such as plasticizers or antistatic agents.  The third part examines the use of ionic liquids in the design of functional polymers (usually called polymeric ionic liquids (PIL) or poly(ionic liquids)). Many important applications in diverse scientific and industrial areas rely on these polymers, like polymer electrolytes in electrochemical devices, building blocks in materials science, nanocomposites, gas membranes, innovative anion sensitive...

Supported ionic liquids: versatile reaction and separation media

DEFF Research Database (Denmark)

Riisager, Anders; Fehrmann, Rasmus; Haumann, Marco

2006-01-01

The latest developments in supported ionic liquid phase (SILP) systems for catalysis and separation technology are surveyed. The SILP concept combines the advantages of homogeneous catalysis with heterogeneous process technology, and a variety of reactions have been studied where supported ionic ...... liquid catalysts proved to be more active and selective than common systems. In separation applications the use of supported ionic liquids can facilitate selective transport of substrates across membranes.......The latest developments in supported ionic liquid phase (SILP) systems for catalysis and separation technology are surveyed. The SILP concept combines the advantages of homogeneous catalysis with heterogeneous process technology, and a variety of reactions have been studied where supported ionic...

μ-nucleon atoms

International Nuclear Information System (INIS)

Dobretsov, Yu.; Dolgoshejn, B.; Kirillov-Ugryumov, V.

1980-01-01

The properties and formation are described of μ-nucleon atoms, the Larmor method of muon spin precession is discussed and the experimental confirmation of the existence of μ-nucleon atoms is shown. The prospects of their use are indicated. (J.P.)

PEG-bis phosphonic acid based ionic supramolecular structures

DEFF Research Database (Denmark)

Gonzalez, Lidia; Skov, Anne Ladegaard; Hvilsted, Søren

2014-01-01

. The resulting ionic assemblies are very comprehensively characterized by ATR-FTIR, proton, and carbon-13 NMR spectroscopy that unequivocally demonstrate the ionic network formation through ammonium phophonates. The resulting salt and ionic networks are additionally analyzed by differential scanning calorimetry...... and thermogravimetric analysis. The conclusion is that mixing the virgin components at room temperature spontaneously form either a salt or ionic supramolecular networks. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim....

The use of a long chain ionic liquid in an LiMn2O4 based lithium ion cell

International Nuclear Information System (INIS)

Sutto, Thomas E.; Duncan, Teresa T.

2012-01-01

A long chain substituted imidazolium ionic liquid, 1,2-dimethyl-3-octylimidazolium bis(trifluoromethanesulfonyl)imide (MMOITFSI), is used as the electrolyte for reversible intercalation of Li into LiMn 2 O 4 . Ionic conductivity measurements indicate that in spite of the longer chain attached to the imidazolium ring, the conductivity for the pure liquid and with 0.5 M LiTFSI present, remains above 1 mS/cm. Cyclic voltammetry revealed high reversibility of Li + into LiMn 2 O 4 in this ionic liquid. Charge/discharge experiments indicated reversible capacity of 115 mAHr/g at a discharge rate of C/6 for 0.5 M Li in MMOITFSI. Higher discharge rates (C/3) resulted in lower capacities (below 100 mAHr/g), most likely due to the higher viscosity of the long chain ionic liquid. Improved discharge rates, of 111 mAHr/g at a higher discharge rate of C/3, were observed when 10 wt% of a short chain ionic liquid, 1,2-dimethyl-3-propylimidazolium bis(trifluoromethanesulfonyl)imide (MMPITFSI), was added to the MMOITFSI. For both the pure MMOITFSI and the ionic liquid blend of MMOITFSI with MMPITFSI, cycle lifetimes showed minimal degradation due to intercalation by the imidazolium cation into the graphite used to enhance the conductivity of the cathode material.

Ion pairing in ionic liquids

International Nuclear Information System (INIS)

Kirchner, Barbara; Malberg, Friedrich; Firaha, Dzmitry S; Hollóczki, Oldamur

2015-01-01

In the present article we briefly review the extensive discussion in literature about the presence or absence of ion pair-like aggregates in ionic liquids. While some experimental studies point towards the presence of neutral subunits in ionic liquids, many other experiments cannot confirm or even contradict their existence. Ion pairs can be detected directly in the gas phase, but no direct method is available to observe such association behavior in the liquid, and the corresponding indirect experimental proofs are based on such assumptions as unity charges at the ions. However, we have shown by calculating ionic liquid clusters of different sizes that assuming unity charges for ILs is erroneous, because a substantial charge transfer is taking place between the ionic liquid ions that reduce their total charge. Considering these effects might establish a bridge between the contradicting experimental results on this matter. Beside these results, according to molecular dynamics simulations the lifetimes of ion–ion contacts and their joint motions are far too short to verify the existence of neutral units in these materials. (topical review)

Nanoarchitecture Control Enabled by Ionic Liquids

Science.gov (United States)

Murdoch, Heather A.; Limmer, Krista R.; Labukas, Joseph P.

2017-04-01

Ionic liquids have many advantages over traditional aqueous electrosynthesis for fabrication of functional nanoarchitectures, including enabling the integration of nanoparticles into traditional coatings, superhydrophobicity, nanofoams, and other hierarchical structures. Shape and size control through ionic liquid selection and processing conditions can synthesize nanoparticles and nanoarchitectures without the use of capping agents, surfactants, or templates that are often deleterious to the functionality of the resultant system. Here we give a brief overview of some recent and interesting applications of ionic liquids to the synthesis of nanoparticles and nanoarchitectures.

Ionic conductivity in irradiated KCL

International Nuclear Information System (INIS)

Vignolo Rubio, J.

1979-01-01

The ionic conductivity of X and gamma irradiated KCl single crystals has been studied between room temperature and 600 deg C. The radiation induced damage resulting in a decrease of the conductivity heals by thermal annealing in two steps which are at about 350 and 550 deg C respectively. It has been found that the radiation induced colour centres are not involved in the observed decrease of the ionic conductivity. Howewer, it has been observed that the effects of quenching and plastic deformation on the conductivity of the samples are very similar to the effect induced by irradiation. It is suggested that small radiation induced dislocation loops might cause the ionic conductivity decrease observed in irradiated samples. (auth)

Ionic conductivity in irradiated KCL

International Nuclear Information System (INIS)

Vignolo Rubio, J.

1979-01-01

The ionic conductivity of X and gamma irradiated KCL single crystals has been studied between room temperature and 600 degree centigree. the radiation induced damage resulting in a decrease of the conductivity heals by thermal annealing in two steps which are at about 350 and 550 degree centigree respectively. It has been found that the radiation induced colour centres are not involved in the observed decrease of the ionic conductivity. However. It has been observed that the effects of quenching and plastic deformation on the conductivity of the samples are very similar to the effect induced by irradiation. It is suggested that, samples radiation induced dislocation loops might cause the ionic conductivity decrease observed in irradiated samples. (Author)

Energy flux of hot atoms

International Nuclear Information System (INIS)

Wotzak, G.P.; Kostin, M.D.

1976-01-01

The process in which hot atoms collide with thermal atoms of a gas, transfer kinetic energy to them, and produce additional hot atoms is investigated. A stochastic method is used to obtain numerical results for the spatial and time dependent energy flux of hot atoms in a gas. The results indicate that in hot atom systems a front followed by an intense energy flux of hot atoms may develop

On-line spectroscopy with thermal atomic beams

International Nuclear Information System (INIS)

Thibault, C.; Guimbal, P.; Klapisch, R.; Saint Simon, M. de; Serre, J.M.; Touchard, F.; Duong, H.T.; Jacquinot, P.; Juncar, P.

1981-01-01

On-line high resolution laser spectroscopy experiments have been performed in which the light from a cw tunable dye laser interacts at right angles with a thermal atomic beam. sup(76-98)Rb, sup(118-145)Cs and sup(208-213)Fr have been studied using the ionic beam delivered by the ISOLDE on-line mass separator at CERN while sup(20-31)Na and sup(38-47)K have been studied by setting the apparaturs directly on-line with the PS 20 GeV proton beam. The principle of the method is briefly explained and some results concerning nuclear structure are given. (orig.)

The Royal Australian College of Radiologists (RACR) survey of reactions to intravenous ionic and non-ionic contrast media

International Nuclear Information System (INIS)

Palmer, J.F.

1989-01-01

The Royal Australian College of Radiologists (RACR) expressed concern as to medico-legal implications of the continued use of conventional ionic contrast media in view of the availability of the new low-osmolar media. The new agents had demonstrated significant advantages and it was anticipated that their use would be associated with a lower incidence of undesirable reactions and deaths. However, these new media are significantly more expensive than conventional ionic media and complete changes to these agents has considerable implications for health budgets. Since it was the view of the RACR that there was insufficient information available of the incidence of reactions in clinical use to justify a complete change, a prospective survey of reations to intravenous contrast media injections was initiated. Particpants were issued a simple form, which required for each patient a record of the presence or absence of risk factors, wether ionic or non-ionic contrast media were used, and of the severity of eventual reactions. The results of about 170.000 patients were reported. The survey demonstrated the relative safety of non-ionic media for intravenous use. Despite the relative high cost of these media the continued use of conventional ionic media will become increasingly difficult to justify. (H.W.). 9 refs.; 4 tabs

Cross sections for atomic processes, vol. 2

International Nuclear Information System (INIS)

Takayanagi, Kazuo; Suzuki, Hiroshi; Otani, Shunsuke

1977-09-01

This data collection book contains the data on all processes involving hydrogen and helium isotopes, their ions, electrons and photons, collected systematically and comprehensively, and is compiled subsequently to Vol. 1 as one of the works of the data collection study group in the Institute of Plasma Physics, Nagoya University, Japan. The items of the contents will include energy level, multiplicately excited state, radiation process, electron collision, ionic collision, recombination, collision of neutral atoms, colliding process involving molecules, and other processes. However, the first edition this time contains energy level, radiation process, electron collision and ionic collision, and the data on remaining items are now under collection. Though some criticisms have been heard about Vol. 1, the authors consider that such comprehensive collection based on systematic classification is the foundation of making a generalized data bank expected to become necessary in future. Thus the data collection book includes all relevant processes, and records the experimental data and theoretically calculated results in principle without modification by selecting them systematically. This year, investigation on data evaluation is taken up also as one of the tasks of the study group. (Wakatsuki, Y.)

Detection of silver nanoparticles in parsley by solid sampling high-resolution-continuum source atomic absorption spectrometry.

Science.gov (United States)

Feichtmeier, Nadine S; Leopold, Kerstin

2014-06-01

In this work, we present a fast and simple approach for detection of silver nanoparticles (AgNPs) in biological material (parsley) by solid sampling high-resolution-continuum source atomic absorption spectrometry (HR-CS AAS). A novel evaluation strategy was developed in order to distinguish AgNPs from ionic silver and for sizing of AgNPs. For this purpose, atomisation delay was introduced as significant indication of AgNPs, whereas atomisation rates allow distinction of 20-, 60-, and 80-nm AgNPs. Atomisation delays were found to be higher for samples containing silver ions than for samples containing silver nanoparticles. A maximum difference in atomisation delay normalised by the sample weight of 6.27 ± 0.96 s mg(-1) was obtained after optimisation of the furnace program of the AAS. For this purpose, a multivariate experimental design was used varying atomisation temperature, atomisation heating rate and pyrolysis temperature. Atomisation rates were calculated as the slope of the first inflection point of the absorbance signals and correlated with the size of the AgNPs in the biological sample. Hence, solid sampling HR-CS AAS was proved to be a promising tool for identifying and distinguishing silver nanoparticles from ionic silver directly in solid biological samples.

Ionic liquids for addressing unmet needs in healthcare

Science.gov (United States)

Agatemor, Christian; Ibsen, Kelly N.; Tanner, Eden E. L.

2018-01-01

Abstract Advances in the field of ionic liquids have opened new applications beyond their traditional use as solvents into other fields especially healthcare. The broad chemical space, rich with structurally diverse ions, and coupled with the flexibility to form complementary ion pairs enables task‐specific optimization at the molecular level to design ionic liquids for envisioned functions. Consequently, ionic liquids now are tailored as innovative solutions to address many problems in medicine. To date, ionic liquids have been designed to promote dissolution of poorly soluble drugs and disrupt physiological barriers to transport drugs to targeted sites. Also, their antimicrobial activity has been demonstrated and could be exploited to prevent and treat infectious diseases. Metal‐containing ionic liquids have also been designed and offer unique features due to incorporation of metals. Here, we review application‐driven investigations of ionic liquids in medicine with respect to current status and future potential. PMID:29376130

A Review of Ionic Liquid Lubricants

Directory of Open Access Journals (Sweden)

Anthony E. Somers

2013-01-01

Full Text Available Due to ever increasing demands on lubricants, such as increased service intervals, reduced volumes and reduced emissions, there is a need to develop new lubricants and improved wear additives. Ionic liquids (ILs are room temperature molten salts that have recently been shown to offer many advantages in this area. The application of ILs as lubricants in a diverse range of systems has found that these materials can show remarkable protection against wear and significantly reduce friction in the neat state. Recently, some researchers have shown that a small family of ILs can also be incorporated into non-polar base oils, replacing traditional anti-wear additives, with excellent performance of the neat IL being maintained. ILs consist of large asymmetrical ions that may readily adsorb onto a metal surface and produce a thin, protective film under boundary lubrication conditions. Under extreme pressure conditions, certain IL compounds can also react to form a protective tribofilm, in particular when fluorine, phosphorus or boron atoms are present in the constituent ions.

Selective gas absorption by ionic liquids

DEFF Research Database (Denmark)

Shunmugavel, Saravanamurugan; Kegnæs, Søren; Due-Hansen, Johannes

2010-01-01

Reversible absorption performance for the flue gas components CO 2, NO and SO2 has been tested for several different ionic liquids (ILs) at different temperatures and flue gas compositions. Furthermore, different porous, high surface area carriers have been applied as supports for the ionic liquids...... to obtain Supported Ionic Liquid-Phase (SILP) absorber materials. The use of solid SILP absorbers with selected ILs were found to significantly improve the absorption capacity and sorption dynamics at low flue gas concentration, thus making the applicability of ILs viable in technical, continuous flow...... processes for flue gas cleaning. The results show that CO 2, NO and SO2 can be reversible and selective absorbed using different ILs and that Supported Ionic Liquid-Phase (SILP) absorbers are promising materials for industrial flue gas cleaning. Absorption/desorption dynamics can be tuned by temperatures...

Minor Actinide Separations Using Ion Exchangers Or Ionic Liquids

International Nuclear Information System (INIS)

Hobbs, D.; Visser, A.; Bridges, N.

2011-01-01

This project seeks to determine if (1) inorganic-based ion exchange materials or (2) electrochemical methods in ionic liquids can be exploited to provide effective Am and Cm separations. Specifically, we seek to understand the fundamental structural and chemical factors responsible for the selectivity of inorganic-based ion-exchange materials for actinide and lanthanide ions. Furthermore, we seek to determine whether ionic liquids can serve as the electrolyte that would enable formation of higher oxidation states of Am and other actinides. Experiments indicated that pH, presence of complexants and Am oxidation state exhibit significant influence on the uptake of actinides and lanthanides by layered sodium titanate and hybrid zirconium and tin phosphonate ion exchangers. The affinity of the ion exchangers increased with increasing pH. Greater selectivity among Ln(III) ions with sodium titanate materials occurs at a pH close to the isoelectric potential of the ion exchanger. The addition of DTPA decreased uptake of Am and Ln, whereas the addition of TPEN generally increases uptake of Am and Ln ions by sodium titanate. Testing confirmed two different methods for producing Am(IV) by oxidation of Am(III) in ionic liquids (ILs). Experimental results suggest that the unique coordination environment of ionic liquids inhibits the direct electrochemical oxidation of Am(III). The non-coordinating environment increases the oxidation potential to a higher value, while making it difficult to remove the inner coordination of water. Both confirmed cases of Am(IV) were from the in-situ formation of strong chemical oxidizers.

Combination of lasers and synchrotron radiation in studies of atomic photoionization

International Nuclear Information System (INIS)

Meyer, M.

2009-01-01

Recent experiments using the combination of conventional lasers and synchrotron radiation are presented and discussed. The controlled laser-manipulation of atoms prior to ionization by the synchrotron radiation provides an ideal experimental basis for detailed investigations of atomic photoionization. Due to the recent advances in high-resolution electron spectroscopy, it has become possible to analyze the J-resolved fine structure of the final ionic states in the photoionization of laser-excited atoms enabling thereby the determination of the specific influence of the outer electron to the ionization from inner subshells. Especially, the analysis of photoemission satellites and their relative intensities bring out directly the importance of electron correlations. Furthermore, it is shown through some examples of experiments using linearly and circularly polarized radiations, how the study of magnetic dichroisms in the photoionization opens the access to a complete description of the photoionization process, in particular to the determination of partial photoionization cross-sections.

Atomic excitation and acceleration in strong laser fields

International Nuclear Information System (INIS)

Zimmermann, H; Eichmann, U

2016-01-01

Atomic excitation in the tunneling regime of a strong-field laser–matter interaction has been recently observed. It is conveniently explained by the concept of frustrated tunneling ionization (FTI), which naturally evolves from the well-established tunneling picture followed by classical dynamics of the electron in the combined laser field and Coulomb field of the ionic core. Important predictions of the FTI model such as the n distribution of Rydberg states after strong-field excitation and the dependence on the laser polarization have been confirmed in experiments. The model also establishes a sound basis to understand strong-field acceleration of neutral atoms in strong laser fields. The experimental observation has become possible recently and initiated a variety of experiments such as atomic acceleration in an intense standing wave and the survival of Rydberg states in strong laser fields. Furthermore, the experimental investigations on strong-field dissociation of molecules, where neutral excited fragments after the Coulomb explosion of simple molecules have been observed, can be explained. In this review, we introduce the subject and give an overview over relevant experiments supplemented by new results. (paper)

Dynamic dielectrophoresis model of multi-phase ionic fluids.

Directory of Open Access Journals (Sweden)

Ying Yan

Full Text Available Ionic-based dielectrophoretic microchips have attracted significant attention due to their wide-ranging applications in electro kinetic and biological experiments. In this work, a numerical method is used to simulate the dynamic behaviors of ionic droplets in a microchannel under the effect of dielectrophoresis. When a discrete liquid dielectric is encompassed within a continuous fluid dielectric placed in an electric field, an electric force is produced due to the dielectrophoresis effect. If either or both of the fluids are ionic liquids, the magnitude and even the direction of the force will be changed because the net ionic charge induced by an electric field can affect the polarization degree of the dielectrics. However, using a dielectrophoresis model, assuming ideal dielectrics, results in significant errors. To avoid the inaccuracy caused by the model, this work incorporates the electrode kinetic equation and defines a relationship between the polarization charge and the net ionic charge. According to the simulation conditions presented herein, the electric force obtained in this work has an error exceeding 70% of the actual value if the false effect of net ionic charge is not accounted for, which would result in significant issues in the design and optimization of experimental parameters. Therefore, there is a clear motivation for developing a model adapted to ionic liquids to provide precise control for the dielectrophoresis of multi-phase ionic liquids.

Dynamic dielectrophoresis model of multi-phase ionic fluids.

Science.gov (United States)

Yan, Ying; Luo, Jing; Guo, Dan; Wen, Shizhu

2015-01-01

Ionic-based dielectrophoretic microchips have attracted significant attention due to their wide-ranging applications in electro kinetic and biological experiments. In this work, a numerical method is used to simulate the dynamic behaviors of ionic droplets in a microchannel under the effect of dielectrophoresis. When a discrete liquid dielectric is encompassed within a continuous fluid dielectric placed in an electric field, an electric force is produced due to the dielectrophoresis effect. If either or both of the fluids are ionic liquids, the magnitude and even the direction of the force will be changed because the net ionic charge induced by an electric field can affect the polarization degree of the dielectrics. However, using a dielectrophoresis model, assuming ideal dielectrics, results in significant errors. To avoid the inaccuracy caused by the model, this work incorporates the electrode kinetic equation and defines a relationship between the polarization charge and the net ionic charge. According to the simulation conditions presented herein, the electric force obtained in this work has an error exceeding 70% of the actual value if the false effect of net ionic charge is not accounted for, which would result in significant issues in the design and optimization of experimental parameters. Therefore, there is a clear motivation for developing a model adapted to ionic liquids to provide precise control for the dielectrophoresis of multi-phase ionic liquids.

Ionic liquids, tuneable solvents for intensifying reactions and separations

NARCIS (Netherlands)

Meindersma, G.W.; Kuipers, N.J.M.; Haan, de A.B.

2007-01-01

An Ionic Liquid (IL), or a Room Temperature Ionic Liquid (RTIL), is commonly defined as a liquid entirely composed of ions, which is a fluid below 100 °C. Due to the fact that an ionic liquid is a salt, it has a negligible vapour pressure. Therefore, ionic liquids are not volatile at ambient process

Atomic and ionic spectrum lines below 2000A: hydrogen through argon

International Nuclear Information System (INIS)

Kelly, R.L.

1982-10-01

A critical tabulation of observed spectral lines below 2000 angstroms has been prepared from the published literature up to July 1978. It is intended principally as an aid to those physicists and astronomers who deal with the spectra of highly stripped atoms. This report includes the first 18 elements, from hydrogen (including deuterium) through argon. The tabulation is divided into two main sections: the spectrum lines by spectrum, and a finding list. The entries for each element give the ionization species, ground state term, and ionization potential, as well as the best values of vacuum wavelength, intensity, and classification. A list of the pertinent references is appended at the end

Ionic polarization

International Nuclear Information System (INIS)

Mahan, G.D.

1992-01-01

Ferroelectricity occurs in many different kinds of materials. Many of the technologically important solids, which are ferroelectric, can be classified as ionic. Any microscopic theory of ferroelectricity must contain a description of local polarization forces. We have collaborated in the development of a theory of ionic polarization which is quite successful. Its basic assumption is that the polarization is derived from the properties of the individual ions. We have applied this theory successfully to diverse subjects as linear and nonlinear optical response, phonon dispersion, and piezoelectricity. We have developed numerical methods using the local Density approximation to calculate the multipole polarizabilities of ions when subject to various fields. We have also developed methods of calculating the nonlinear hyperpolarizability, and showed that it can be used to explain light scattering experiments. This paper elaborates on this polarization theory

Application of Ionic Liquids in Amperometric Gas Sensors.

Science.gov (United States)

Gębicki, Jacek; Kloskowski, Adam; Chrzanowski, Wojciech; Stepnowski, Piotr; Namiesnik, Jacek

2016-01-01

This article presents an analysis of available literature data on metrological parameters of the amperometric gas sensors containing ionic liquids as an electrolyte. Four mechanism types of signal generation in amperometric sensors with ionic liquid are described. Moreover, this article describes the influence of selected physico-chemical properties of the ionic liquids on the metrological parameters of these sensors. Some metrological parameters are also compared for amperometric sensors with GDE and SPE electrodes and with ionic liquids for selected analytes.

Ionic Liquids as Extraction Media for Metal Ions

Science.gov (United States)

Hirayama, Naoki

In solvent extraction separation of metal ions, recently, many researchers have investigated possible use of hydrophobic ionic liquids as extraction media instead of organic solvents. Ionic liquids are salts of liquid state around room temperature and can act not only as solvents but also as ion-exchangers. Therefore, the extraction mechanism of metal ions into ionic liquids is complicated. This review presents current overview and perspective on evaluation of nature of hydrophobic ionic liquids as extraction media for metal ions.

Recent applications of ionic liquids in the sol-gel process for polymer-silica nanocomposites with ionic interfaces

Czech Academy of Sciences Publication Activity Database

Donato, K. Z.; Matějka, Libor; Mauler, R. S.; Donato, R. K.

2017-01-01

Roč. 1, č. 1 (2017), s. 1-25, č. článku 5. E-ISSN 2504-5377 Institutional support: RVO:61389013 Keywords : ionic liquids * sol-gel * ionic interfaces Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science

Ionic liquid stationary phases for gas chromatography.

Science.gov (United States)

Poole, Colin F; Poole, Salwa K

2011-04-01

This article provides a summary of the development of ionic liquids as stationary phases for gas chromatography beginning with early work on packed columns that established details of the retention mechanism and established working methods to characterize selectivity differences compared with molecular stationary phases through the modern development of multi-centered cation and cross-linked ionic liquids for high-temperature applications in capillary gas chromatography. Since there are many reviews on ionic liquids dealing with all aspects of their chemical and physical properties, the emphasis in this article is placed on the role of gas chromatography played in the design of ionic liquids of low melting point, high thermal stability, high viscosity, and variable selectivity for separations. Ionic liquids provide unprecedented opportunities for extending the selectivity range and temperature-operating range of columns for gas chromatography, an area of separation science that has otherwise been almost stagnant for over a decade. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

On the Chemical Stabilities of Ionic Liquids

OpenAIRE

Yen-Ho Chu; Ming-Chung Tseng; Venkatesan Srinivasadesikan; Subbiah Sowmiah

2009-01-01

Ionic liquids are novel solvents of interest as greener alternatives to conventional organic solvents aimed at facilitating sustainable chemistry. As a consequence of their unusual physical properties, reusability, and eco-friendly nature, ionic liquids have attracted the attention of organic chemists. Numerous reports have revealed that many catalysts and reagents were supported in the ionic liquid phase, resulting in enhanced reactivity and selectivity in various important reaction transfor...

Diffusion, electrical mobility and ionic interactions in molten Salts

International Nuclear Information System (INIS)

Lantelme, F.

1965-05-01

The diffusion and the electrical migration of ions in the molten alkali nitrates LiNO 3 , NaNO 3 and KNO 3 and in their mixtures have been examined using stable or radio-active isotope indicators. This experimental works shows that there are large differences in the diffusion coefficients and the electric mobilities when they are compared using the Nernst-Einstein formula. An interpretive model has been put forward which shows the role played by poly-ionic displacements: in a salt AC the particles moving are not only the free ions A - and C + but also the groups [A n C m ] (m-n)+ ... These results confirm the importance of electrostatic attraction and of the polarizability of the ions. This mechanisms, furthermore, explains the inversions of electrical mobilities often observed in liquid ionic media. (author) [fr

Maillard reaction products from chitosan-xylan ionic liquid solution.

Science.gov (United States)

Luo, Yuqiong; Ling, Yunzhi; Wang, Xiaoying; Han, Yang; Zeng, Xianjie; Sun, Runcang

2013-10-15

A facile method is reported to prepare Maillard reaction products (MRPs) from chitosan and xylan in co-solvent ionic liquid. UV absorbance and fluorescence changes were regarded as indicators of the occurrence of Maillard reaction. FT-IR, NMR, XRD and TG were used to investigate the structure of chitosan-xylan conjugate. The results revealed that when chitosan reacted with xylan in ionic liquid, the hydrogen bonds in chitosan were destroyed, the facts resulted in the formation of chitosan-xylan MRPs. Moreover, when the mass ratio of chitosan to xylan was 1:1, the Maillard reaction proceeded easily. In addition, relatively high antioxidant property was also noted for the chitosan-xylan conjugate with mass ratio 1:1. So the obtained chitosan-xylan MRP is a promising antioxidant agent for food industry. Copyright © 2013 Elsevier Ltd. All rights reserved.

Polypyrrole for Artificial Muscles: Ionic Mechanisms

DEFF Research Database (Denmark)

Skaarup, Steen

2006-01-01

the matrix of a polymer electrode – thereby causing volume expansion which can be converted into work. Solvent molecules are able to penetrate the polymer too. A precise description of the nature of these ionic and solvent movements is therefore important for understanding and improving the performance....... This work examines the influence of solvent, ionic species and electrolyte concentration on the fundamental question about the ionic mechanism involved: Is the actuation process driven by anion motion, cation motion, or a mixture of the two? In addition: What is the extent of solvent motion? The discussion...... is centered on polypyrrole (PPy), which is the material most used and studied. The tetraethyl ammonium cation (TEA) is shown to be able to move in and out of PPy(DBS) polymer films, in contrast to expectations. There is a switching between ionic mechanisms during cycling in TEACl electrolyte....

Specific ionic effect for simple and rapid colorimetric sensing assays of amino acids using gold nanoparticles modified with task-specific ionic liquid

Energy Technology Data Exchange (ETDEWEB)

Wu, Datong; Cai, Pengfei; Tao, Zhihao; Pan, Yuanjiang, E-mail: panyuanjiang@zju.edu.cn

2016-01-01

In this study, a novel task-specific ionic liquid functionalized gold nanoparticle (TSIL-GNP) was successfully prepared and applied in the recognition of amino acids. Particularly, the surface of GNP was modified with the ionic liquid containing carbamido and ester group via thiol, which was characterized by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The stability of this material in aqueous solution improves apparently and can remain unchanged for more than three months. The effect of pH was also discussed in this study. Attractive ionic interaction would effectively weaken intensity of the covalent coupling between the metal ion and the functional groups of amino acids. Thus, TSIL-GNP was successfully applied to recognizing serine, aspartic acid, lysine, arginine, and histidine in the presence of Cu{sup 2+} through distinctive color changes. Suspension would be generated once a spot of cysteine was added into the GNPs solution. Results indicated that it had a good linear relationship between extinction coefficients and concentration of amino acids in a wide range of 10{sup −3}–10{sup −6} M. Moreover, the proposed strategy was successfully used to analyze the histidine in urinary samples. In brief, TSIL-GNP is a suitable substrate for discrimination of five amino acids in a rapid and simple way without sophisticated instruments. - Highlights: • A novel task-specific ionic liquid functionalized gold nanoparticle was successfully prepared. • This material was successfully applied to recognizing five amino acids with Cu(II) through distinctive color changes. • The proposed strategy was successfully used to analyze the histidine in real samples.

A novel microextraction technique based on 1-hexylpyridinium hexafluorophosphate ionic liquid for the preconcentration of zinc in water and milk samples

International Nuclear Information System (INIS)

Abdolmohammad-Zadeh, H.; Sadeghi, G.H.

2009-01-01

A simple dispersive liquid-liquid microextraction methodology based on the application of 1-hexylpyridinium hexafluorophosphate [HPy][PF 6 ] ionic liquid (IL) as an extractant solvent was proposed for the preconcentration of trace levels of zinc as a prior step to determination by flame atomic absorption spectrometry (FAAS). Zinc was complexed with 8-hydroxyquinoline (oxine) and extracted into ionic liquid. Some effective factors that influence the microextraction efficiency such as pH, oxine concentration, amount of IL, ionic strength, temperature and centrifugation time were investigated and optimized. In the optimum experimental conditions, the limit of detection (3 s) and the enhancement factor were 0.22 μg L -1 and 71, respectively. The relative standard deviation (RSD) for six replicate determinations of 13 μg L -1 Zn was 1.92%. In order to validate the developed method, a certified reference material (NIST SRM 1549) was analyzed and the determined values were in good agreement with the certified values. The proposed method was successfully applied to the trace determination of zinc in water and milk samples.

Thermoelectric Generators Based on Ionic Liquids

Science.gov (United States)

Laux, Edith; Uhl, Stefanie; Jeandupeux, Laure; López, Pilar Pérez; Sanglard, Pauline; Vanoli, Ennio; Marti, Roger; Keppner, Herbert

2018-06-01

Looking at energy harvesting using body or waste heat for portable electronic or on-board devices, Ionic liquids are interesting candidates as thermoactive materials in thermoelectric generators (TEGs) because of their outstanding properties. Two different kinds of ionic liquid, with alkylammonium and choline as cations, were studied, whereby different anions and redox couples were combined. This study focussed on the intention to find non-hazardous and environmentally friendly ionic liquids for TEGs to be selected among the thousands that can potentially be used. Seebeck coefficients (SEs) as high as - 15 mV/K were measured, in a particular case for an electrode temperature difference of 20 K. The bottleneck of our TEG device is still the abundance of negative SE liquids matching the internal resistance with the existing positive SE-liquids at series connections. In this paper, we show further progress in finding increased negative SE liquids. For current extraction from the TEG, the ionic liquid must be blended with a redox couple, allowing carrier exchange in a cyclic process under a voltage which is incuced by the asymmetry of the generator in terms of hot and cold electrodes. In our study, two types of redox pairs were tested. It was observed that a high SE of an ionic liquid/redox blend is not a sufficient condition for high power output. It appears that more complex effects between the ionic liquid and the electrode determine the magnitude of the final current/power output. The physico-chemical understanding of such a TEG cell is not yet available.

A novel task specific magnetic polymeric ionic liquid for selective preconcentration of potassium in oil samples using centrifuge-less dispersive liquid-liquid microextraction technique and its determination by flame atomic emission spectroscopy.

Science.gov (United States)

Beiraghi, Asadollah; Shokri, Masood

2018-02-01

In the present study a new centrifuge-less dispersive liquid-liquid microextraction technique based on application of a new task specific magnetic polymeric ionic liquid (TSMPIL) as a chelating and extraction solvent for selective preconcentration of trace amounts of potassium from oil samples is developed, for the first time. After extraction, the fine droplets of TSMPIL were transferred into an eppendorf tube and diluted to 500µL using distilled water. Then, the enriched analyte was determined by flame atomic emission spectroscopy (FAES). Several important factors affecting both the complexation and extraction efficiency including extraction time, rate of vortex agitator, amount of carbonyl iron powder, pH of sample solution, volume of ionic liquid as well as effects of interfering species were investigated and optimized. Under the optimal conditions, the limits of detection (LOD) and quantification (LOQ) were 0.5 and 1.6µgL -1 respectively with the preconcentration factor of 128. The precision (RSD %) for seven replicate determinations at 10µgL -1 of potassium was better than 3.9%. The relative recoveries for the spiked samples were in the acceptable range of 95-104%. The results demonstrated that no remarkable interferences are created by other various ions in the determination of potassium, so that the tolerance limits (W Ion /W K ) of major cations and anions were in the range of 2500-10,000. The purposed method was successfully applied for the analysis of potassium in some oil samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Clarifying atomic weights: A 2016 four-figure table of standard and conventional atomic weights

Science.gov (United States)

Coplen, Tyler B.; Meyers, Fabienne; Holden, Norman E.

2017-01-01

To indicate that atomic weights of many elements are not constants of nature, in 2009 and 2011 the Commission on Isotopic Abundances and Atomic Weights (CIAAW) of the International Union of Pure and Applied Chemistry (IUPAC) replaced single-value standard atomic weight values with atomic weight intervals for 12 elements (hydrogen, lithium, boron, carbon, nitrogen, oxygen, magnesium, silicon, sulfur, chlorine, bromine, and thallium); for example, the standard atomic weight of nitrogen became the interval [14.00643, 14.00728]. CIAAW recognized that some users of atomic weight data only need representative values for these 12 elements, such as for trade and commerce. For this purpose, CIAAW provided conventional atomic weight values, such as 14.007 for nitrogen, and these values can serve in education when a single representative value is needed, such as for molecular weight calculations. Because atomic weight values abridged to four figures are preferred by many educational users and are no longer provided by CIAAW as of 2015, we provide a table containing both standard atomic weight values and conventional atomic weight values abridged to four figures for the chemical elements. A retrospective review of changes in four-digit atomic weights since 1961 indicates that changes in these values are due to more accurate measurements over time or to the recognition of the impact of natural isotopic fractionation in normal terrestrial materials upon atomic weight values of many elements. Use of the unit “u” (unified atomic mass unit on the carbon mass scale) with atomic weight is incorrect because the quantity atomic weight is dimensionless, and the unit “amu” (atomic mass unit on the oxygen scale) is an obsolete term: Both should be avoided.

Potentiostatic control of ionic liquid surface film formation on ZE41 magnesium alloy.

Science.gov (United States)

Efthimiadis, Jim; Neil, Wayne C; Bunter, Andrew; Howlett, Patrick C; Hinton, Bruce R W; MacFarlane, Douglas R; Forsyth, Maria

2010-05-01

The generation of potentially corrosion-resistant films on light metal alloys of magnesium have been investigated. Magnesium alloy, ZE41 [Mg-Zn-Rare Earth (RE)-Zr, nominal composition approximately 4 wt % Zn, approximately 1.7 wt % RE (Ce), approximately 0.6 wt % Zr, remaining balance, Mg], was exposed under potentiostatic control to the ionic liquid trihexyl(tetradecyl)phosphonium diphenylphosphate, denoted [P(6,6,6,14)][DPP]. During exposure to this IL, a bias potential, shifted from open circuit, was applied to the ZE41 surface. Electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA) were used to monitor the evolution of film formation on the metal surface during exposure. The EIS data indicate that, of the four bias potentials examined, applying a potential of -200 mV versus OCP during the exposure period resulted in surface films of greatest resistance. Both EIS measurements and scanning electron microscopy (SEM) imaging indicate that these surfaces are substantially different to those formed without potential bias. Time of flight-secondary ion mass spectrometry (ToF-SIMS) elemental mapping of the films was utilized to ascertain the distribution of the ionic liquid cationic and anionic species relative to the microstructural surface features of ZE41 and indicated a more uniform distribution compared with the surface following exposure in the absence of a bias potential. Immersion of the treated ZE41 specimens in a chloride contaminated salt solution clearly indicated that the ionic liquid generated surface films offered significant protection against pitting corrosion, although the intermetallics were still insufficiently protected by the IL and hence favored intergranular corrosion processes.

Regio and stereoselectivity in ionic cycloadditions

Indian Academy of Sciences (India)

WINTEC

Though the reactions have both electrostatic control and frontier orbital control the former dominates in the initial stages of the reaction. Keywords. Stereoselectivity; ionic cycloaddition; density functional theory; acridizinium ion; methyl vinyl ether; 2,3-dimethylisoquinolinium ion. 1. Introduction. In polar or ionic cycloadditions ...

Extraction and preconcentration of trace Al and Cr from vegetable samples by vortex-assisted ionic liquid-based dispersive liquid-liquid microextraction prior to atomic absorption spectrometric determination.

Science.gov (United States)

Altunay, Nail; Yıldırım, Emre; Gürkan, Ramazan

2018-04-15

In the study, a simple, and efficient microextraction approach, which is termed as vortex-assisted ionic liquid-based dispersive liquid-liquid microextraction (VA-IL-DLLME), was developed for flame atomic absorption spectrometric analysis of aluminum (Al) and chromium (Cr) in vegetables. The method is based on the formation of anionic chelate complexes of Al(III) and Cr(VI) with o-hydroxy azo dye, at pH 6.5, and then extraction of the hydrophobic ternary complexes formed in presence of cetyltrimethylammonium bromide (CTAB) into a 125 μL volume of 1-butyl-3-methylimidazolium bis(trifluorosulfonyl)imide [C 4 mim][Tf 2 N]) as extraction solvent. Under optimum conditions, the detection limits were 0.02 µg L -1 in linear working range of 0.07-100 µg L -1 for Al(III), and 0.05 µg L -1 in linear working range of 0.2-80 µg L -1 for Cr(VI). After the validation by analysis of a certified reference material (CRM), the method was successfully applied to the determination of Al and Cr in vegetables using standard addition method. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ionic cluster size distributions of swollen nafion/sulfated beta-cyclodextrin membranes characterized by nuclear magnetic resonance cryoporometry.

Science.gov (United States)

Jeon, Jae-Deok; Kwak, Seung-Yeop

2007-08-16

Nafion/sb-CD membranes were prepared by mixing 5 wt% Nafion solution with H+-form sulfated beta-cyclodextrin (sb-CD), and their water uptakes, ion exchange capacities (IECs), and ionic cluster size distributions were measured. Gravimetric and thermogravimetric measurements showed that the water uptake of the membranes increased with increases in their sb-CD content. The IECs of the membrane were measured with acid-base titration and found to increase with increases in the sb-CD content, reaching 0.96 mequiv/g for NC5 ("NCx" denotes a Nafion/sb-CD composite membrane containing x wt% of sb-CD). The cluster-correlation peaks and ionic cluster size distributions of the water-swollen membranes were determined using small-angle X-ray scattering (SAXS) and 1H nuclear magnetic resonance (NMR) cryoporometry, respectively. The SAXS experiments confirmed that increases in the sb-CD content of the membranes shifted the maximum SAXS peaks to lower angles, indicating an increase in the cluster correlation peak. NMR cryoporometry is based on the theory of the melting point depression, Delta Tm, of a liquid confined within a pore, which is dependent on the pore diameter. The melting point depression was determined by analyzing the variation of the NMR signal intensity with temperature. Our analysis of the intensity-temperature (IT) curves showed that the ionic cluster size distribution gradually became broader with increases in the membrane sb-CD content due to the increased water content, indicating an increase in the ionic cluster size. This result indicates that the presence of sb-CD with its many sulfonic acid sites in the Nafion membranes results in increases in the ionic cluster size as well as in the water uptake and the IEC. We conclude that NMR cryoporometry provides a method for determining the ionic cluster size on the nanometer scale in an aqueous environment, which cannot be obtained using other methods.

Ionic liquid electrolytes for dye-sensitized solar cells.

Science.gov (United States)

Gorlov, Mikhail; Kloo, Lars

2008-05-28

The potential of room-temperature molten salts (ionic liquids) as solvents for electrolytes for dye-sensitized solar cells has been investigated during the last decade. The non-volatility, good solvent properties and high electrochemical stability of ionic liquids make them attractive solvents in contrast to volatile organic solvents. Despite this, the relatively high viscosity of ionic liquids leads to mass-transport limitations. Here we review recent developments in the application of different ionic liquids as solvents or components of liquid and quasi-solid electrolytes for dye-sensitized solar cells.

Active chemisorption sites in functionalized ionic liquids for carbon capture.

Science.gov (United States)

Cui, Guokai; Wang, Jianji; Zhang, Suojiang

2016-07-25

Development of novel technologies for the efficient and reversible capture of CO2 is highly desired. In the last decade, CO2 capture using ionic liquids has attracted intensive attention from both academia and industry, and has been recognized as a very promising technology. Recently, a new approach has been developed for highly efficient capture of CO2 by site-containing ionic liquids through chemical interaction. This perspective review focuses on the recent advances in the chemical absorption of CO2 using site-containing ionic liquids, such as amino-based ionic liquids, azolate ionic liquids, phenolate ionic liquids, dual-functionalized ionic liquids, pyridine-containing ionic liquids and so on. Other site-containing liquid absorbents such as amine-based solutions, switchable solvents, and functionalized ionic liquid-amine blends are also investigated. Strategies have been discussed for how to activate the existent reactive sites and develop novel reactive sites by physical and chemical methods to enhance CO2 absorption capacity and reduce absorption enthalpy. The carbon capture mechanisms of these site-containing liquid absorbents are also presented. Particular attention has been paid to the latest progress in CO2 capture in multiple-site interactions by amino-free anion-functionalized ionic liquids. In the last section, future directions and prospects for carbon capture by site-containing ionic liquids are outlined.

Contrast enhanced cartilage imaging: Comparison of ionic and non-ionic contrast agents

International Nuclear Information System (INIS)

Wiener, Edzard; Woertler, Klaus; Weirich, Gregor; Rummeny, Ernst J.; Settles, Marcus

2007-01-01

Our objective was to compare relaxation effects, dynamics and spatial distributions of ionic and non-ionic contrast agents in articular cartilage at concentrations typically used for direct MR arthrography at 1.5 T. Dynamic MR-studies over 11 h were performed in 15 bovine patella specimens. For each of the contrast agents gadopentetate dimeglumine, gadobenate dimeglumine, gadoteridol and mangafodipir trinatrium three patellae were placed in 2.5 mmol/L contrast solution. Simultaneous measurements of T 1 and T 2 were performed every 30 min using a high-spatial-resolution 'MIX'-sequence. T 1 , T 2 and ΔR 1 , ΔR 2 profile plots across cartilage thickness were calculated to demonstrate the spatial and temporal distributions. The charge is one of the main factors which controls the amount of the contrast media diffusing into intact cartilage, but independent of the charge, the spatial distribution across cartilage thickness remains highly inhomogeneous even after 11 h of diffusion. The absolute ΔR 2 -effect in cartilage is at least as large as the ΔR 1 -effect for all contrast agents. Maximum changes were 5-12 s -1 for ΔR 1 and 8-15 s -1 for ΔR 2 . This study indicates that for morphologically intact cartilage only the amount of contrast agents within cartilage is determined by the charge but not the spatial distribution across cartilage thickness. In addition, ΔR 2 can be considered for quantification of contrast agent concentrations, since it is of the same magnitude and less time consuming to measure than ΔR 1

Ionic Liquid Epoxy Resin Monomers

Science.gov (United States)

Paley, Mark S. (Inventor)

2013-01-01

Ionic liquid epoxide monomers capable of reacting with cross-linking agents to form polymers with high tensile and adhesive strengths. Ionic liquid epoxide monomers comprising at least one bis(glycidyl) N-substituted nitrogen heterocyclic cation are made from nitrogen heterocycles corresponding to the bis(glycidyl) N-substituted nitrogen heterocyclic cations by a method involving a non-nucleophilic anion, an alkali metal cation, epichlorohydrin, and a strong base.

Studies in solid state ionics

International Nuclear Information System (INIS)

Jakes, D.; Rosenkranz, J.

1987-01-01

Studies performed over 10 years by the high temperature chemistry group are reviewed. Attention was paid to different aspects of ionic solids from the point of view of practical as well as theoretical needs of nuclear technology. Thus ceramic fuel compound like uranates, urania-thoria system, solid electrolytes based on oxides and ionics transformations were studied under reactor irradiation. (author) 13 figs., 3 tabs., 46 refs

Freezing of liquid alkali metals as screened ionic plasmas

International Nuclear Information System (INIS)

Badirkhan, Z.; Rovere, M.; Tosi, M.P.

1990-08-01

The relationship between Wigner crystallization of the classical ionic plasma and the liquid-solid transition of alkali metals is examined within the density wave theory of freezing. Freezing of the classical plasma on a rigid neutralizing background into the bcc structure is first re-evaluated, in view of recent progress in the determination of its thermodynamic functions by simulation and of the known difficulties of the theory relating to the order parameter at the (200) star of reciprocal lattice vectors. Freezing into the fcc structure is also considered in this context and found to be unfavoured. On allowing for long-wavelength deformability of the background, the ensuing appearance of a volume change on freezing into the bcc structure is accompanied by reduced stability of the fluid phase and by an increase in the entropy of melting. Freezing of alkali metals into the bcc structure is next evaluated, taking their ionic pair structure as that of an ionic plasma reference fluid screened by conduction electrons and asking that the correct ionic coupling strength at liquid-solid coexistence should be approximately reproduced. The ensuring values of the volume and entropy changes across the phase transition, as estimated from the theory by two alternative routes, are in reasonable agreement with experiment. The order parameters of the phase transition, excepting the (200) one, conform rather closely to a Gaussian behaviour and yield a Lindemann ratio in reasonable agreement with the empirical value for melting of bcc crystals. It is suggested that ionic ordering at the (200) star in the metal may be (i) assisted by medium range ordering in the conduction electrons, as indicated by differences in X-ray and neutron diffraction intensities from the liquid, and/or (ii) quite small in the hot bcc solid. Such a possible premelting behaviour of bcc metals should be worth testing experimentally by diffraction. (author). 48 refs, 1 fig., 1 tab

WtF‐Nano: One‐Pot Dewatering and Water‐Free Topochemical Modification of Nanocellulose in Ionic Liquids or γ‐Valerolactone

Science.gov (United States)

Laaksonen, Tiina; Helminen, Jussi K. J.; Lemetti, Laura; Långbacka, Jesper; Rico del Cerro, Daniel; Hummel, Michael; Rantamäki, Antti H.; Kakko, Tia; Kemell, Marianna L.; Wiedmer, Susanne K.; Heikkinen, Sami; Kilpeläinen, Ilkka

2017-01-01

Abstract Ionic liquids are used to dewater a suspension of birch Kraft pulp cellulose nanofibrils (CNF) and as a medium for water‐free topochemical modification of the nanocellulose (a process denoted as “WtF‐Nano”). Acetylation was applied as a model reaction to investigate the degree of modification and scope of effective ionic liquid structures. Little difference in reactivity was observed when water was removed, after introduction of an ionic liquid or molecular co‐solvent. However, the viscoelastic properties of the CNF suspended in two ionic liquids show that the more basic, but non‐dissolving ionic liquid, allows for better solvation of the CNF. Vibrio fischeri bacterial tests show that all ionic liquids in this study were harmless. Scanning electron microscopy and wide‐angle X‐ray scattering on regenerated samples show that the acetylated CNF is still in a fibrillar form. 1 D and 2 D NMR analyses, after direct dissolution in a novel ionic liquid electrolyte solution, indicate that both cellulose and residual xylan on the surface of the nanofibrils reacts to give acetate esters. PMID:29112334

Determination of sulfonamides in butter samples by ionic liquid magnetic bar liquid-phase microextraction high-performance liquid chromatography.

Science.gov (United States)

Wu, Lijie; Song, Ying; Hu, Mingzhu; Xu, Xu; Zhang, Hanqi; Yu, Aimin; Ma, Qiang; Wang, Ziming

2015-01-01

A novel, simple, and environmentally friendly pretreatment method, ionic liquid magnetic bar liquid-phase microextraction, was developed for the determination of sulfonamides in butter samples by high-performance liquid chromatography. The ionic liquid magnetic bar was prepared by inserting a stainless steel wire into the hollow of a hollow fiber and immobilizing ionic liquid in the micropores of the hollow fiber. In the extraction process, the ionic liquid magnetic bars were used to stir the mixture of sample and extraction solvent and enrich the sulfonamides in the mixture. After extraction, the analyte-adsorbed ionic liquid magnetic bars were readily isolated with a magnet from the extraction system. It is notable that the present method was environmentally friendly since water and only several microliters of ionic liquid were used in the whole extraction process. Several parameters affecting the extraction efficiency were investigated and optimized, including the type of ionic liquid, sample-to-extraction solvent ratio, the number of ionic liquid magnetic bars, extraction temperature, extraction time, salt concentration, stirring speed, pH of the extraction solvent, and desorption conditions. The recoveries were in the range of 73.25-103.85 % and the relative standard deviations were lower than 6.84 %. The experiment results indicated that the present method was effective for the extraction of sulfonamides in high-fat content samples.

Ionic conductivity, structural deformation, and programmable anisotropy of DNA origami in electric field.

Science.gov (United States)

Li, Chen-Yu; Hemmig, Elisa A; Kong, Jinglin; Yoo, Jejoong; Hernández-Ainsa, Silvia; Keyser, Ulrich F; Aksimentiev, Aleksei

2015-02-24

The DNA origami technique can enable functionalization of inorganic structures for single-molecule electric current recordings. Experiments have shown that several layers of DNA molecules, a DNA origami plate, placed on top of a solid-state nanopore is permeable to ions. Here, we report a comprehensive characterization of the ionic conductivity of DNA origami plates by means of all-atom molecular dynamics (MD) simulations and nanocapillary electric current recordings. Using the MD method, we characterize the ionic conductivity of several origami constructs, revealing the local distribution of ions, the distribution of the electrostatic potential and contribution of different molecular species to the current. The simulations determine the dependence of the ionic conductivity on the applied voltage, the number of DNA layers, the nucleotide content and the lattice type of the plates. We demonstrate that increasing the concentration of Mg(2+) ions makes the origami plates more compact, reducing their conductivity. The conductance of a DNA origami plate on top of a solid-state nanopore is determined by the two competing effects: bending of the DNA origami plate that reduces the current and separation of the DNA origami layers that increases the current. The latter is produced by the electro-osmotic flow and is reversible at the time scale of a hundred nanoseconds. The conductance of a DNA origami object is found to depend on its orientation, reaching maximum when the electric field aligns with the direction of the DNA helices. Our work demonstrates feasibility of programming the electrical properties of a self-assembled nanoscale object using DNA.

Application of ionic liquids based enzyme-assisted extraction of chlorogenic acid from Eucommia ulmoides leaves

Energy Technology Data Exchange (ETDEWEB)

Liu, Tingting; Sui, Xiaoyu, E-mail: suixiaoyu@outlook.com; Li, Li; Zhang, Jie; Liang, Xin; Li, Wenjing; Zhang, Honglian; Fu, Shuang

2016-01-15

A new approach for ionic liquid based enzyme-assisted extraction (ILEAE) of chlorogenic acid (CGA) from Eucommia ulmoides is presented in which enzyme pretreatment was used in ionic liquids aqueous media to enhance extraction yield. For this purpose, the solubility of CGA and the activity of cellulase were investigated in eight 1-alkyl-3-methylimidazolium ionic liquids. Cellulase in 0.5 M [C6mim]Br aqueous solution was found to provide better performance in extraction. The factors of ILEAE procedures including extraction time, extraction phase pH, extraction temperatures and enzyme concentrations were investigated. Moreover, the novel developed approach offered advantages in term of yield and efficiency compared with other conventional extraction techniques. Scanning electronic microscopy of plant samples indicated that cellulase treated cell wall in ionic liquid solution was subjected to extract, which led to more efficient extraction by reducing mass transfer barrier. The proposed ILEAE method would develope a continuous process for enzyme-assisted extraction including enzyme incubation and solvent extraction process. In this research, we propose a novel view for enzyme-assisted extraction of plant active component, besides concentrating on enzyme facilitated cell wall degradation, focusing on improvement of bad permeability of ionic liquids solutions. - Highlights: • An ionic liquid based enzyme-assisted extraction method of natural product was explored. • ILEAE utilizes enzymatic treatment to improve permeability of ionic liquids solution. • Enzyme incubation and solvent extraction process were ongoing simultaneously. • ILEAE process simplified operating process and suitable for more complete extraction.

Application of ionic liquids based enzyme-assisted extraction of chlorogenic acid from Eucommia ulmoides leaves

International Nuclear Information System (INIS)

Liu, Tingting; Sui, Xiaoyu; Li, Li; Zhang, Jie; Liang, Xin; Li, Wenjing; Zhang, Honglian; Fu, Shuang

2016-01-01

A new approach for ionic liquid based enzyme-assisted extraction (ILEAE) of chlorogenic acid (CGA) from Eucommia ulmoides is presented in which enzyme pretreatment was used in ionic liquids aqueous media to enhance extraction yield. For this purpose, the solubility of CGA and the activity of cellulase were investigated in eight 1-alkyl-3-methylimidazolium ionic liquids. Cellulase in 0.5 M [C6mim]Br aqueous solution was found to provide better performance in extraction. The factors of ILEAE procedures including extraction time, extraction phase pH, extraction temperatures and enzyme concentrations were investigated. Moreover, the novel developed approach offered advantages in term of yield and efficiency compared with other conventional extraction techniques. Scanning electronic microscopy of plant samples indicated that cellulase treated cell wall in ionic liquid solution was subjected to extract, which led to more efficient extraction by reducing mass transfer barrier. The proposed ILEAE method would develope a continuous process for enzyme-assisted extraction including enzyme incubation and solvent extraction process. In this research, we propose a novel view for enzyme-assisted extraction of plant active component, besides concentrating on enzyme facilitated cell wall degradation, focusing on improvement of bad permeability of ionic liquids solutions. - Highlights: • An ionic liquid based enzyme-assisted extraction method of natural product was explored. • ILEAE utilizes enzymatic treatment to improve permeability of ionic liquids solution. • Enzyme incubation and solvent extraction process were ongoing simultaneously. • ILEAE process simplified operating process and suitable for more complete extraction.

Assessment of the Density Functional Tight Binding Method for Protic Ionic Liquids.

Science.gov (United States)

Addicoat, Matthew A; Stefanovic, Ryan; Webber, Grant B; Atkin, Rob; Page, Alister J

2014-10-14

Density functional tight binding (DFTB), which is ∼100-1000 times faster than full density functional theory (DFT), has been used to simulate the structure and properties of protic ionic liquid (IL) ions, clusters of ions and the bulk liquid. Proton affinities for a wide range of IL cations and anions determined using DFTB generally reproduce G3B3 values to within 5-10 kcal/mol. The structures and thermodynamic stabilities of n -alkyl ammonium nitrate clusters (up to 450 quantum chemical atoms) predicted with DFTB are in excellent agreement with those determined using DFT. The IL bulk structure simulated using DFTB with periodic boundary conditions is in excellent agreement with published neutron diffraction data.

Structure and Dynamics of Hydroxyl-Functionalized Protic Ammonium Carboxylate Ionic Liquids.

Science.gov (United States)

Thummuru, Dhileep Nagi Reddy; Mallik, Bhabani S

2017-10-26

We performed classical molecular dynamics simulations to investigate the structure and dynamics of protic ionic liquids, 2-hydroxy ethylammonium acetate, ethylammonium hydroxyacetate, and 2-hydroxyethylammonium hydroxyacetate at ambient conditions. Structural properties such as density, radial distribution functions, spatial distribution functions, and structure factors have been calculated. Dynamic properties such as mean square displacements, as well as residence and hydrogen bond dynamics have also been calculated. Hydrogen bond lifetimes and residence times change with the addition of hydroxyl groups. We observe that when a hydroxyl group is present on the cation, dynamics become very slow and it forms a strong hydrogen bond with carboxylate oxygen atoms of the anion. The hydroxyl functionalized ILs show more dynamic diversity than structurally similar ILs.

Electroresistance effect in gold thin film induced by ionic-liquid-gated electric double layer

International Nuclear Information System (INIS)

Nakayama, Hiroyasu; Ohtani, Takashi; Fujikawa, Yasunori; Ando, Kazuya; Saitoh, Eiji; Ye, Jianting; Iwasa, Yoshihiro

2012-01-01

Electroresistance effect was detected in a metallic thin film using ionic-liquid-gated electric-double-layer transistors (EDLTs). We observed reversible modulation of the electric resistance of a Au thin film. In this system, we found that an electric double layer works as a nanogap capacitor with 27 (-25) MV cm -1 of electric field by applying only 1.7 V of positive (negative) gate voltage. The experimental results indicate that the ionic-liquid-gated EDLT technique can be used for controlling the surface electronic states on metallic systems. (author)

Elimination of ionic interference effects in the atomic absorption spectrometric determination of ruthenium

International Nuclear Information System (INIS)

El-Defrawy, M.M.M.; Posta, J.; Beck, M.T.

1978-01-01

In connection with work on the catalytic effect of ruthenium complexes, new compounds were prepared. Atomic absorption spectrometry (a.a.s.) was to be used for their analysis. The standard methods could not be applied to the complexes studied, therefore the effect of cyanide ions for elimination of interfering effects has been studied, because of the great stability of cyanide complexes. (Auth.)

Ionic liquid gel materials: applications in green and sustainable chemistry

OpenAIRE

Marr, Patricia C.; Marr, Andrew C.

2016-01-01

Ionic liquid gel materials offer a way to further utilise ionic liquids in technological applications. Combining the controlled and directed assembly of gels, with the diverse applications of ionic liquids, enables the design of a heady combination of functional tailored materials, leading to the development of task specific / functional ionic liquid gels. This review introduces gels and gel classification, focusing on ionic liquid gels and their potential roles in a more sustainable future. ...

Observation of atomic arrangement by using photoelectron holography and atomic stereo-photograph

International Nuclear Information System (INIS)

Matsushita, Tomohiro; Guo, Fang Zhun; Agui, Akane; Matsui, Fumihiko; Daimon, Hiroshi

2006-01-01

Both a photoelectron holography and atomic stereo-photograph are the atomic structure analysis methods on the basis of photoelectron diffraction. They have six special features such as 1) direct determination of atomic structure, 2) measurement of three dimensional atomic arrangements surrounding of specific element in the sample, 3) determination of position of atom in spite of electron cloud, 4) unnecessary of perfect periodic structure, 5) good sensitivity of structure in the neighborhood of surface and 6) information of electron structure. Photoelectron diffraction, the principle and measurement system of photoelectron holography and atomic stereo-photograph is explained. As application examples of atomic stereo-photograph, the single crystal of cupper and graphite are indicated. For examples of photoelectron holography, Si(001)2p and Ge(001)3s are explained. (S.Y.)

Notre Dame Geothermal Ionic Liquids Research: Ionic Liquids for Utilization of Geothermal Energy

Energy Technology Data Exchange (ETDEWEB)

Brennecke, Joan F. [Univ. of Notre Dame, IN (United States)

2017-03-07

The goal of this project was to develop ionic liquids for two geothermal energy related applications. The first goal was to design ionic liquids as high temperature heat transfer fluids. We identified appropriate compounds based on both experiments and molecular simulations. We synthesized the new ILs, and measured their thermal stability, measured storage density, viscosity, and thermal conductivity. We found that the most promising compounds for this application are aminopyridinium bis(trifluoromethylsulfonyl)imide based ILs. We also performed some measurements of thermal stability of IL mixtures and used molecular simulations to better understand the thermal conductivity of nanofluids (i.e., mixtures of ILs and nanoparticles). We found that the mixtures do not follow ideal mixture theories and that the addition of nanoparticles to ILs may well have a beneficial influence on the thermal and transport properties of IL-based heat transfer fluids. The second goal was to use ionic liquids in geothermally driven absorption refrigeration systems. We performed copious thermodynamic measurements and modeling of ionic liquid/water systems, including modeling of the absorption refrigeration systems and the resulting coefficients of performance. We explored some IL/organic solvent mixtures as candidates for this application, both with experimentation and molecular simulations. We found that the COPs of all of the IL/water systems were higher than the conventional system – LiBr/H2O. Thus, IL/water systems appear very attractive for absorption refrigeration applications.

Chemical Stability of Cd(II and Cu(II Ionic Imprinted Amino-Silica Hybrid Material in Solution Media

Directory of Open Access Journals (Sweden)

Buhani, Narsito, Nuryono, Eko Sri Kunarti

2015-12-01

Full Text Available Chemical stability of Cd(II and Cu(II ionic imprinted hybrid material of (i-Cd-HAS and i-Cu-HAS derived from silica modification with active compound (3-aminopropyl-trimethoxysilane (3-APTMS has been studied in solution media. Stability test was performed with HNO3 0.1 M (pH 1.35 to investigate material stability at low pH condition, CH3COONa 0.1 M (pH 5.22 for adsorption process optimum pH condition, and in the water (pH 9.34 for base condition. Material characteristics were carried out with infrared spectrophotometer (IR and atomic absorption spectrophotometer (AAS. At interaction time of 4 days in acid and neutral condition, i-Cd-HAS is more stable than i-Cu-HAS with % Si left in material 95.89 % (acid media, 43.82 % (close to neutral, and 9.39 % (base media.Keywords: chemical stability, amino-silica hybrid, ionic imprinting technique

Chemical Stability of Cd(II and Cu(II Ionic Imprinted Amino-Silica Hybrid Material in Solution Media

Directory of Open Access Journals (Sweden)

Buhani Buhani

2012-02-01

Full Text Available Chemical stability of Cd(II and Cu(II ionic imprinted amino-silica (HAS material of (i-Cd-HAS and i-Cu-HAS derived from silica modification with active compound (3-aminopropyl-trimethoxysilane (3-APTMS has been studied in solution media.  Stability test was performed with HNO3 0.1 M (pH 1.35 to investigate material stability at low pH condition, acetat buffer at pH 5.22 for adsorption process optimum pH condition, and in the water (pH 9.34 for base condition.  Material characteristics were carried out with infrared spectrophotometer (IR and atomic absorption spectrophotometer (AAS.  At interaction time of 4 days in acid and neutral condition, i-Cd-HAS is more stable than i-Cu-HAS with % Si left in material 95.89 % (acid media, 43.82 % (close to neutral, and 9.39 % (base media.Keywords: chemical stability, amino-silica hybrid, ionic imprinting technique.

Using Balls of Different Sports To Model the Variation of Atomic Sizes

Science.gov (United States)

Pinto, Gabriel

1998-06-01

In this article, an analogy is described about the order of magnitude of the variation of atomic sizes that can be used for discussion in introductory chemistry classes. The order of magnitude of this variation, involving microscopic magnitudes, is difficult for students to imagine. For the most part, the students are very familiar with the world of sports. In any case for example, the teacher can make use of the wide, informative coverage given to the olympic games or similar events, where different sports are televised in a few days. The radii of official balls for seven well-known sports are given, and students must assign an atom to each ball by using tabulated single-bond, covalent radii and by assigning the smallest ball (i.e., corresponding to ping-pong) to the smallest atom (i.e., hydrogen). The balls can also be used to show how the ionic radii change upon ionization.

Lewis acidic (choline chloride.3ZnCl2) ionic liquid: A green and ...

Indian Academy of Sciences (India)

Choline chloride; zinc chloride; ionic liquid; one-pot; triarylmethane. 1. Introduction ... applications such as zinc electroplating11 and batter- ies.12 It has also been used as ... as indicated by Thin Layer Chromatography (TLC), the catalyst was ...

Measurement and Correlation of the Ionic Conductivity of Ionic Liquid-Molecular Solvent Solutions

Institute of Scientific and Technical Information of China (English)

LI,Wen-Jing; HAN,Bu-Xing; TAO,Ran-Ting; ZHANG,Zhao-Fu; ZHANG,Jian-Ling

2007-01-01

The ionic conductivity of the solutions formed from 1-n-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) or 1-n-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF6]) and different molecular solvents (MSs) were measured at 298.15 K. The molar conductivity of the ionic liquids (ILs) increased dramatically with increasing concentration of the MSs. It was found that the molar conductivity of the IL in the solutions studied in this work could be well correlated by the molar conductivity of the neat ILs and the dielectric constant and molar volume of the MSs.

Excimer Formation Dynamics of Dipyrenyldecane in Structurally Different Ionic Liquids.

Science.gov (United States)

Yadav, Anita; Pandey, Siddharth

2017-12-07

Ionic liquids, being composed of ions alone, may offer alternative pathways for molecular aggregation. These pathways could be controlled by the chemical structure of the cation and the anion of the ionic liquids. Intramolecular excimer formation dynamics of a bifluorophoric probe, 1,3-bis(1-pyrenyl)decane [1Py(10)1Py], where the fluorophoric pyrene moieties are separated by a long decyl chain, is investigated in seven different ionic liquids in 10-90 °C temperature range. The long alkyl separator allows for ample interaction with the solubilizing milieu prior to the formation of the excimer. The ionic liquids are composed of two sets, one having four ionic liquids of 1-butyl-3-methylimidazolium cation ([bmim + ]) with different anions and the other having four ionic liquids of bis(trifluoromethylsulfonyl)imide anion ([Tf 2 N - ]) with different cations. The excimer-to-monomer emission intensity ratio (I E /I M ) is found to increase with increasing temperature in sigmoidal fashion. Chemical structure of the ionic liquid controls the excimer formation efficiency, as I E /I M values within ionic liquids with the same viscosities are found to be significantly different. The excited-state intensity decay kinetics of 1Py(10)1Py in ionic liquids do not adhere to a simplistic Birk's scheme, where only one excimer conformer forms after excitation. The apparent rate constants of excimer formation (k a ) in highly viscous ionic liquids are an order of magnitude lower than those reported in organic solvents. In general, the higher the viscosity of the ionic liquid, the more sensitive is the k a to the temperature with higher activation energy, E a . The trend in E a is found to be similar to that for activation energy of the viscous flow (E a,η ). Stokes-Einstein relationship is not followed in [bmim + ] ionic liquids; however, with the exception of [choline][Tf 2 N], it is found to be followed in [Tf 2 N - ] ionic liquids suggesting the cyclization dynamics of 1Py(10)1Py

Course on Ionic Channels

CERN Document Server

1986-01-01

This book is based on a series of lectures for a course on ionic channels held in Santiago, Chile, on November 17-20, 1984. It is intended as a tutorial guide on the properties, function, modulation, and reconstitution of ionic channels, and it should be accessible to graduate students taking their first steps in this field. In the presentation there has been a deliberate emphasis on the spe­ cific methodologies used toward the understanding of the workings and function of channels. Thus, in the first section, we learn to "read" single­ channel records: how to interpret them in the theoretical frame of kinetic models, which information can be extracted from gating currents in re­ lation to the closing and opening processes, and how ion transport through an open channel can be explained in terms of fluctuating energy barriers. The importance of assessing unequivocally the origin and purity of mem­ brane preparations and the use of membrane vesicles and optical tech­ niques in the stUGY of ionic channels a...

Numerical modeling of ultrasonic cavitation in ionic liquids

Science.gov (United States)

Calvisi, Michael L.; Elder, Ross M.

2017-11-01

Ionic liquids have favorable properties for sonochemistry applications in which the high temperatures and pressures achieved by cavitation bubbles are important drivers of chemical processes. Two different numerical models are presented to simulate ultrasonic cavitation in ionic liquids, each with different capabilities and physical assumptions. A model based on a compressible form of the Rayleigh-Plesset equation (RPE) simulates ultrasonic cavitation of a spherical bubble with a homogeneous interior, incorporating evaporation and condensation at the bubble surface, and temperature-varying thermodynamic properties in the interior. A second, more computationally intensive model of a spherical bubble uses the finite element method (FEM) and accounts for spatial variations in pressure and temperature throughout the flow domain. This model provides insight into heat transfer across the bubble surface and throughout the bubble interior and exterior. Parametric studies are presented for sonochemistry applications involving ionic liquids as a solvent, examining a range of realistic ionic liquid properties and initial conditions to determine their effect on temperature and pressure. Results from the two models are presented for parametric variations including viscosity, thermal conductivity, water content of the ionic liquid solvent, acoustic frequency, and initial bubble pressure. An additional study performed with the FEM model examines thermal penetration into the surrounding ionic liquid during bubble oscillation. The results suggest the prospect of tuning ionic liquid properties for specific applications.

Photophysical processes of ionic crystals exitation at photosorption and photocatalysis. Fotofizicheskie protsessy vozbuzhdeniya ionnykh kristallov pri fotovozbuzhdenii i fotokatalize

Energy Technology Data Exchange (ETDEWEB)

Ryabchuk, V K; Burukina, G V [Leningradskij Gosudarstvennyj Univ., Leningrad (Russian Federation). Nauchno-Issledovatel' skij Fizicheskij Inst.

1991-06-01

Processes of photoexcitation of wide-band oxides and alkali-halide crystals (AHC) within intrinsic absorption range, of impurity absorption and surface states and photoinduced colour centers resulting in development of centers of photosorption and photocatalysis are considered. Mechanisms of effect of photosorption of O[sub 2], H[sub 2], CH[sub 4] and other molecules on photostimulated defect formation in oxides and AHC as well as atomic and ionic processes in photosorption and photocatalysis are dicussed.

Ionic liquid containing hydroxamate and N-alkyl sulfamate ions

Science.gov (United States)

Friesen, Cody A.; Wolfe, Derek; Johnson, Paul Bryan

2016-03-15

Embodiments of the invention are related to ionic liquids and more specifically to ionic liquids used in electrochemical metal-air cells in which the ionic liquid includes a cation and an anion selected from hydroxamate and/or N-alkyl sulfamate anions.

Thioimidazolium Ionic Liquids as Tunable Alkylating Agents.

Science.gov (United States)

Guterman, Ryan; Miao, Han; Antonietti, Markus

2018-01-19

Alkylating ionic liquids based on the thioimidazolium structure combine the conventional properties of ionic liquids, including low melting point and nonvolatility, with the alkylating function. Alkyl transfer occurs exclusively from the S-alkyl position, thus allowing for easy derivatization of the structure without compromising specificity. We apply this feature to tune the electrophilicty of the cation to profoundly affect the reactivity of these alkylating ionic liquids, with a caffeine-derived compound possessing the highest reactivity. Anion choice was found to affect reaction rates, with iodide anions assisting in the alkylation reaction through a "shuttling" process. The ability to tune the properties of the alkylating agent using the toolbox of ionic liquid chemistry highlights the modular nature of these compounds as a platform for alkylating agent design and integration in to future systems.

Ionomer design for augmented charge transport in novel ionic polymer transducers

International Nuclear Information System (INIS)

Duncan, Andrew J; Akle, Barbar J; Long, Timothy E; Leo, Donald J

2009-01-01

Ionic polymer transducers are devices that display electromechanical transduction and are projected to have extensive applications as actuators and sensors. This study employs novel, highly branched sulfonated polysulfones (sBPS) as part of an investigation into the contribution of polymer topology to electromechanical transduction. Specifically, the ionomers are combined with an ionic liquid to determine the optimal ratio and method for maximizing ionic conductivity, where charge transport is essential to device performance. Two uptake methods are assessed for introduction of ionic liquid into the central ionomeric membrane. The effects of casting membranes in the presence of ionic liquid and swelling preformed membranes in ionic liquid on film stability and ionic conductivity are examined. Membranes cast from a solution of the ionomer and ionic liquid allow for direct targeting of the component ratio and a single-step process for membrane formation. Swelling conditions for preformed neat membranes combine time, temperature, and the presence of organic co-diluents to achieve the maximum stable uptake of ionic liquid. Comparison of optimal conditions for the various methods reveals that swelling with co-diluents achieves ionic conductivity of the imbibed membrane per uptake higher than the levels achieved with the casting process for highly sulfonated sBPS. However, for less sulfonated sBPS the casting process successfully produced membranes with ionic conductivities unreachable with the co-diluent process. Both methods will enable the production of high performance ionic polymer transducers constructed from novel sBPS ionomers and ionic liquids

Analytic properties of the relativistic Thomas-Fermi equation and the total energy of atomic ions

International Nuclear Information System (INIS)

March, N.H.; Senatore, G.

1985-06-01

The analytic properties of solutions of the relativistic Thomas-Fermi equation which tend to zero at infinity are first examined, the neutral atom solution being a member of this class. A new length is shown to enter the theory, proportional to the square root of the fine structure constant. This information is used to develop a perturbation expansion around the neutral atom solution, corresponding to positive atomic ions with finite but large radii. The limiting law relating ionic radius to the degree of ionization is thereby displayed in functional form, and solved explicitly to lowest order in the fine structure constant. To embrace this knowledge of heavy positive ions, as well as results from the one-electron Dirac equation, a proposal is then advanced as to the analytic form of the relativistic total energy E(Z,N) of an atomic ion with nuclear charge Ze and total number of electrons N. The fact that, for N>1, the nucleus is known only to bind Z+n electrons, where n is 1 or 2, indicates non-analyticity in the complex Z plane, represented by a circle of radius Z approx.= N. Such non-analyticity is also a property of the non-relativistic energy derived from the many-electron Schroedinger equation. The relativistic theory, however, must also embody a second type of non-analyticity associated with the known property for N=1 that the Dirac equation predicts electron-positron pair production when the electronic binding energy becomes equal to twice the electron rest mass energy. This corresponds to a second circle of non-analyticity in E(Z,N), and hence to a Taylor-Laurent expansion of this quantity in the atomic number Z. The relation of this expansion to the Layzer-Bahcall series is finally discussed. (author)

Fe electron transfer and atom exchange in goethite: influence of Al-substitution and anion sorption.

Science.gov (United States)

Latta, Drew E; Bachman, Jonathan E; Scherer, Michelle M

2012-10-02

The reaction of Fe(II) with Fe(III) oxides and hydroxides is complex and includes sorption of Fe(II) to the oxide, electron transfer between sorbed Fe(II) and structural Fe(III), reductive dissolution coupled to Fe atom exchange, and, in some cases mineral phase transformation. Much of the work investigating electron transfer and atom exchange between aqueous Fe(II) and Fe(III) oxides has been done under relatively simple aqueous conditions in organic buffers to control pH and background electrolytes to control ionic strength. Here, we investigate whether electron transfer is influenced by cation substitution of Al(III) in goethite and the presence of anions such as phosphate, carbonate, silicate, and natural organic matter. Results from (57)Fe Mössbauer spectroscopy indicate that both Al-substitution (up to 9%) and the presence of common anions (PO(4)(3-), CO(3)(2-), SiO(4)(4-), and humic acid) does not inhibit electron transfer between aqueous Fe(II) and Fe(III) in goethite under the conditions we studied. In contrast, sorption of a long-chain phospholipid completely shuts down electron transfer. Using an enriched isotope tracer method, we found that Al-substitution in goethite (10%), does, however, significantly decrease the extent of atom exchange between Fe(II) and goethite (from 43 to 12%) over a month's time. Phosphate, somewhat surprisingly, appears to have little effect on the rate and extent of atom exchange between aqueous Fe(II) and goethite. Our results show that electron transfer between aqueous Fe(II) and solid Fe(III) in goethite can occur under wide range of geochemical conditions, but that the extent of redox-driven Fe atom exchange may be dependent on the presence of substituting cations such as Al.

Functional ionic liquids; Funktionelle ionische Fluessigkeiten

Energy Technology Data Exchange (ETDEWEB)

Baecker, Tobias

2012-07-01

In the thesis at hand, new functional ionic liquids were investigated. Main focus was attended to their structure property relations and the structural features leading to a decrease of the melting point. New compounds of the type 1-butyl-3-methylimidazolium tris(N,Ndialkyldithiocarbamato) uranylate with variously substituated dithiocarbamato ligands were synthesized and characterized. Ligands with asymmetrical substitution pattern proved to be most suitable for ionic liquid formation. The single-crystal X-ray structures revealed the interactions in the solid state. Here, the first spectroscopic investigation of the U-S bond in sulfur donated uranyl complexes, up to now only observed in single-crystal X-ray structures, is presented, and the participation of the uranium f-orbitals is shown by theoretical calculations. Electrochemical investigations showed the accessibility of the respective U{sup V}O{sub 2}{sup +} compounds. As well, ionic liquids with [FeCl{sub 4}]{sup -} and [Cl{sub 3}FeOFeCl{sub 3}]{sup 2-} as anion were synthesized. Both of these anions contain high-spin Fe(III) centres in distorted tetrahedral environment, but exhibit different magnetic behaviour. The tetrachloroferrates show the usual paramagnetism, the m-oxobis(trichloroferrate) exhibits unexpectedly strong antiferromagnetic coupling, as was observed by NMR experiments and susceptibility measurements. To investigate structure-property relations in functionalized ionic liquids, a set of protic, primary alkylammonium and aprotic, quarternary trimethylalkylammonium based ionic liquids was synthesized, and characterized. The length of the alkyl chain was systematically varied, and all compounds were synthesized with and without hydroxyl group, as well as formate and bis(triflyl)amide salts, aiming at getting insight into the influence of the different structure parts on the respective ionic liquid's properties.

CADDIS Volume 2. Sources, Stressors and Responses: Ionic Strength - Simple Conceptual Diagram

Science.gov (United States)

Introduction to the ionic strength module, when to list ionic strength as a candidate cause, ways to measure ionic strength, simple and detailed conceptual diagrams for ionic strength, ionic strength module references and literature reviews.

CADDIS Volume 2. Sources, Stressors and Responses: Ionic Strength - Detailed Conceptual Diagram

Science.gov (United States)

Introduction to the ionic strength module, when to list ionic strength as a candidate cause, ways to measure ionic strength, simple and detailed conceptual diagrams for ionic strength, ionic strength module references and literature reviews.

Ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate, an efficient solvent for extraction of acetone from aqueous solutions

International Nuclear Information System (INIS)

Saien, Javad; Badieh, Marjan Mohammadi Sarab; Norouzi, Mahdi; Salehzadeh, Sadegh

2015-01-01

Highlights: • The use of HMIMPF_6 as a green ionic was feasible in the extraction of acetone from water. • The binodal curves were determined by cloud point measurement method. • High level separation factor of acetone between the ionic liquid and water were achieved. • The thermodynamic properties of HMIMPF_6 were obtained by the Density Functional Theory calculations. • The NRTL and UNIQUAC models were applied satisfactorily to correlate the equilibrium data. - Abstract: (Liquid + liquid) equilibrium (LLE) of the chemical system of {water + acetone + 1-Hexyl-3-methylimidazolium hexafluorophosphate (HMIMPF_6) ionic liquid} was studied at different temperatures of (293.2, 298.2 and 303.2) K and under atmospheric pressure of 81.5 kPa. The results show that HMIMPF_6 provides the acetone distribution coefficient and separation factor values within (0.8813 to 1.2351) and (3.0 to 54.4), respectively; indicating the high capability of the ionic liquid for extraction of acetone from aqueous solutions. In most cases, acetone solubility in the ionic liquid is higher than in water, especially at higher solute concentrations. Meanwhile, higher separation factor is relevant to the lower temperature due to lower (water + ionic liquid) miscibility. The consistency of tie line data, at each temperature, was examined with Othmer–Tobias correlation. The values were nicely reproduced with the well-known NRTL and UNIQUAC models. Accordingly, the required thermodynamic properties of HMIMPF_6 were obtained by the Density Functional Theory (DFT) calculations, carried out at the M06/6-311++G"∗"∗ level of theory. The root mean square deviations (RMSD) between experimental and model concentration values were 0.0192 and 0.0255, respectively; indicating close agreement of the both models.

Key Developments in Ionic Liquid Crystals.

Science.gov (United States)

Alvarez Fernandez, Alexandra; Kouwer, Paul H J

2016-05-16

Ionic liquid crystals are materials that combine the classes of liquid crystals and ionic liquids. The first one is based on the multi-billion-dollar flat panel display industry, whilst the latter quickly developed in the past decades into a family of highly-tunable non-volatile solvents. The combination yields materials with a unique set of properties, but also with many challenges ahead. In this review, we provide an overview of the key concepts in ionic liquid crystals, particularly from a molecular perspective. What are the important molecular parameters that determine the phase behavior? How should they be introduced into the molecules? Finally, which other tools does one have to realize specific properties in the material?

Key Developments in Ionic Liquid Crystals

Directory of Open Access Journals (Sweden)

Alexandra Alvarez Fernandez

2016-05-01

Full Text Available Ionic liquid crystals are materials that combine the classes of liquid crystals and ionic liquids. The first one is based on the multi-billion-dollar flat panel display industry, whilst the latter quickly developed in the past decades into a family of highly-tunable non-volatile solvents. The combination yields materials with a unique set of properties, but also with many challenges ahead. In this review, we provide an overview of the key concepts in ionic liquid crystals, particularly from a molecular perspective. What are the important molecular parameters that determine the phase behavior? How should they be introduced into the molecules? Finally, which other tools does one have to realize specific properties in the material?

Physicochemical properties of fatty acid based ionic liquids

International Nuclear Information System (INIS)

Rocha, Marisa A.A.; Bruinhorst, Adriaan van den; Schröer, Wolffram; Rathke, Bernd; Kroon, Maaike C.

2016-01-01

Highlights: • Effects of a branched anion and a mono-unsaturated anion on the physicochemical properties have been explored. • Fatty acid based ionic liquids were synthesized and characterized. • Densities and viscosities at different temperatures have been measured. • The thermal operating window and thermal phase behavior have been evaluated. - Abstract: In this work a series of fatty acid based ionic liquids has been synthesized and characterized. Densities and viscosities at different temperatures have been measured in the temperature range from (293.15 to 363.15) K. The thermal operating window and thermal phase behavior have been evaluated. The effects of a branched anion and a mono-unsaturated anion on the physicochemical properties have been explored. It has been observed that the density (T = 298.15 K) decreases with the following sequence: methyltrioctylammonium 4-ethyloctanoate > methyltrioctylammonium oleate ≈ tetrahexylammonium oleate > tetraoctylammonium oleate, with no detectable dependency of the thermal expansion coefficients on the total number of carbons in the ionic liquid. An almost linear correlation between the molar volumes and the total number of carbons of the alkanes together with the studied ionic liquids was found. The experimental viscosity data were correlated using the Vogel–Fulcher–Tammann (VFT) equation, where a maximum relative deviation of 1.4% was achieved. The ionic liquid with branched alkyl chains on the anion presents the highest viscosity, and methyltrioctylammonium oleate has the highest viscosity compared to the rest of the oleate based ionic liquids. The short and long-term stability were evaluated for all ionic liquids, their long-term decomposition temperatures were found to be significantly lower than their short-term decomposition temperatures. From the long-term thermal analysis was concluded that the highest temperature at which these ionic liquids can be kept is 363 K. In addition, the thermal

Synthetic Organic Electrochemistry in Ionic Liquids: The Viscosity Question

Directory of Open Access Journals (Sweden)

Scott T. Handy

2011-07-01

Full Text Available Ionic liquids are obvious candidates for use in electrochemical applications due to their ionic character. Nevertheless, relatively little has been done to explore their application in electrosynthesis. We have studied the Shono oxidation of arylamines and carbamates using ionic liquids as recyclable solvents and have noted that the viscosity of the medium is a major problem, although with the addition of sufficient co-solvent, good results and excellent recovery and recycling of the ionic liquid can be achieved.

Self-consistent field theory of polymer-ionic molecule complexation

OpenAIRE

Nakamura, Issei; Shi, An-Chang

2010-01-01

A self-consistent field theory is developed for polymers that are capable of binding small ionic molecules (adsorbates). The polymer-ionic molecule association is described by Ising-like binding variables, C_(i)^(a)(kΔ)(= 0 or 1), whose average determines the number of adsorbed molecules, nBI. Polymer gelation can occur through polymer-ionic molecule complexation in our model. For polymer-polymer cross-links through the ionic molecules, three types of solutions for nBI are obtained, depending...

Empirical Modeling of ICMEs Using ACE/SWICS Ionic Distributions

Science.gov (United States)

Rivera, Y.; Landi, E.; Lepri, S. T.; Gilbert, J. A.

2017-12-01

Coronal Mass Ejections (CMEs) are some of the largest, most energetic events in the solar system releasing an immense amount of plasma and magnetic field into the Heliosphere. The Earth-bound plasma plays a large role in space weather, causing geomagnetic storms that can damage space and ground based instrumentation. As a CME is released, the plasma experiences heating, expansion and acceleration; however, the physical mechanism supplying the heating as it lifts out of the corona still remains uncertain. From previous work we know the ionic composition of solar ejecta undergoes a gradual transition to a state where ionization and recombination processes become ineffective rendering the ionic composition static along its trajectory. This property makes them a good indicator of thermal conditions in the corona, where the CME plasma likely receives most of its heating. We model this so-called `freeze-in' process in Earth-directed CMEs using an ionization code to empirically determine the electron temperature, density and bulk velocity. `Frozen-in' ions from an ensemble of independently modeled plasmas within the CME are added together to fit the full range of observational ionic abundances collected by ACE/SWICS during ICME events. The models derived using this method are used to estimate the CME energy budget to determine a heating rate used to compare with a variety of heating mechanisms that can sustain the required heating with a compatible timescale.

Ionic conductivity and complexation in liquid dielectrics

International Nuclear Information System (INIS)

Zhakin, Anatolii I

2003-01-01

Electronic and ionic conductivity in nonpolar liquids is reviewed. Theoretical results on ionic complexation (formation of ion pairs and triplets, dipole-dipole chains, ion-dipole clusters) in liquid dielectrics in an intense external electric field are considered, and the relation between the complexation process and ionic conductivity is discussed. Experimental results supporting the possibility of complexation are presented and compared with theoretical calculations. Onsager's theory about the effect of an intense external electric field on ion-pair dissociation is corrected for the finite size of ions. (reviews of topical problems)

The search For Closed Orbits Of General Rydberg Atoms in External Fields And Their Classification

International Nuclear Information System (INIS)

Carboni, R.

1997-01-01

A program of high precision that find closed orbits for the classical motion of the electron of general Rydberg atoms in crossed magnetic and electric fields is explained. Investigations of the influence of the ionic core on the electronic trajectories using a phenomenological model potential were done. Additional closed orbits that are not present in hydrogen atoms and that seem to be composed of hydrogenic orbits were found. The stability and formation of orbits are explained. Using the generalized closed-orbit theory, the scaled recurrence spectra for rubidium Rydberg atoms were calculated. The results are in good agreement with reported experiments. Two important features of the expectra can be explained by classical core scattering: The additional non-hydrogenic resonances associated to composite orbits and the vanishing of hydrogenic resonances related to closed or whose trajectories approach the core. (Author) [es

Multiphoton atomic ionization in the field of a very short laser pulse

International Nuclear Information System (INIS)

Popov, V.S.

2001-01-01

Closed analytic expressions are derived for the probability of multiphoton atomic and ionic ionization in a variable electric field E(t), which are applicable for arbitrary Keldysh parameters γ. Dependencies of the ionization probability and photoelectron pulse spectrum on the shape of a very short laser pulse are analyzed. Examples of pulse fields of various forms, including a modulated light pulse with a Gaussian or Lorentz envelope, are considered in detail. The interference effect in the photoelectron energy spectrum during atomic ionization by a periodic field of a general form is examined. The range of applicability of the adiabatic approximation in the multiphoton ionization theory is discussed. The imaginary time method is used in the calculations, which allows the probability of particle tunneling through oscillating barriers to be effectively calculated

Prediction of the enthalpies of vaporization for room-temperature ionic liquids: Correlations and a substitution-based additive scheme

International Nuclear Information System (INIS)

Kabo, Gennady J.; Paulechka, Yauheni U.; Zaitsau, Dzmitry H.; Firaha, Alena S.

2015-01-01

Highlights: • The available literature data on Δ l g H for ionic liquids were analyzed. • Correlation equations for Δ l g H were derived using symbolic regression. • A substitution-based incremental scheme for Δ l g H was developed. • The proposed scheme has an advantage over the existing predictive procedures. - Abstract: The literature data on the enthalpies of vaporization for aprotic ionic liquids (ILs) published by the end of May 2014 were analyzed and the most reliable Δ l g H m values were derived for 68 ILs. The selected enthalpies of vaporization were correlated with density and surface tension using symbolic regression and a number of effective correlation equations were proposed. The substitution-based incremental scheme for prediction of the enthalpies of vaporization of imidazolium, pyridinium and pyrrolidinium ILs was developed. The standard error of the regression for the developed scheme is significantly lower than that for the atom-based group-contribution schemes proposed earlier

QSTR with extended topochemical atom (ETA) indices. 14. QSAR modeling of toxicity of aromatic aldehydes to Tetrahymena pyriformis

Energy Technology Data Exchange (ETDEWEB)

Roy, Kunal, E-mail: kunalroy_in@yahoo.com [Drug Theoretics and Cheminformatics Laboratory, Division of Medicinal and Pharmaceutical Chemistry, Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700 032 (India); Das, Rudra Narayan [Drug Theoretics and Cheminformatics Laboratory, Division of Medicinal and Pharmaceutical Chemistry, Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700 032 (India)

2010-11-15

Aldehydes are a toxic class of chemicals causing severe health hazards. In this background, quantitative structure-toxicity relationship (QSTR) models have been developed in the present study using Extended Topochemical Atom (ETA) indices for a large group of 77 aromatic aldehydes for their acute toxicity against the protozoan ciliate Tetrahymena pyriformis. The ETA models have been compared with those developed using various non-ETA topological indices. Attempt was also made to include the n-octanol/water partition coefficient (log K{sub o/w}) as an additional descriptor considering the importance of hydrophobicity in toxicity prediction. Thirty different models were developed using different chemometric tools. All the models have been validated using internal validation and external validation techniques. The statistical quality of the ETA models was found to be comparable to that of the non-ETA models. The ETA models have shown the important effects of steric bulk, lipophilicity, presence of electronegative atom containing substituents and functionality of the aldehydic oxygen to the toxicity of the aldehydes. The best ETA model (without using log K{sub o/w}) shows encouraging statistical quality (Q{sub int}{sup 2}=0.709,Q{sub ext}{sup 2}=0.744). It is interesting to note that some of the topological models reported here are better in statistical quality than previously reported models using quantum chemical descriptors.

Dye-sensitized solar cells using ionic liquids as redox mediator

Science.gov (United States)

Denizalti, Serpil; Ali, Abdulrahman Khalaf; Ela, Çağatay; Ekmekci, Mesut; Erten-Ela, Sule

2018-01-01

In this research, the influence of ionic liquid on the conversion efficiency, incident photons to converted electrons (IPCE) and performance of fabricated solar cell was investigated using various ionic liquids. Ionic liquids with different substituents and ions were prepared and used as redox mediators in dye-sensitized solar cells (DSSCs). Ionic liquids were characterized 1H and 13C NMR spectra. We practically investigated the performance of ionic liquid salts were used as the mobile ions and found that the efficiencies of DSSCs were increased up to 40% comparing commercial electrolyte system. The ionic liquid compounds were incorporated in DSSCs to obtain an efficient charge transfer, solving the corrosion problem of platinum layer in counter electrode compared to commercial electrolyte.

Visualization of ionic wind in laminar jet flames

KAUST Repository

Park, Daegeun

2017-07-03

Electric field, when it is applied to hydrocarbon flames, generates ionic wind due to the electric body force on charge carrying species. Ionic wind has been shown to influence soot emission, propagation speed, and stability of flames; however, a detailed behavior of ionic wind and its effects on flames is still not clear. Here, we investigated the dynamic behaviors of flames and ionic wind in the presence of direct current (DC) and alternating current (AC) electric fields in nonpremixed and premixed jet flames with a jet nozzle placed between two parallel electrodes. We observed a skewed flame toward a lower potential electrode with DC and lower frequency AC (e.g., 10Hz) and a steady flame with higher frequencies AC (1000Hz), while we found that the ionic wind blew toward both the anode and cathode regardless of flame type (nonpremixed or premixed) or the source of the electric field (DC and AC).

Counterion-induced swelling of ionic microgels

Science.gov (United States)

Denton, Alan R.; Tang, Qiyun

2016-10-01

Ionic microgel particles, when dispersed in a solvent, swell to equilibrium sizes that are governed by a balance between electrostatic and elastic forces. Tuning of particle size by varying external stimuli, such as pH, salt concentration, and temperature, has relevance for drug delivery, microfluidics, and filtration. To model swelling of ionic microgels, we derive a statistical mechanical theorem, which proves exact within the cell model, for the electrostatic contribution to the osmotic pressure inside a permeable colloidal macroion. Applying the theorem, we demonstrate how the distribution of counterions within an ionic microgel determines the internal osmotic pressure. By combining the electrostatic pressure, which we compute via both Poisson-Boltzmann theory and molecular dynamics simulation, with the elastic pressure, modeled via the Flory-Rehner theory of swollen polymer networks, we show how deswelling of ionic microgels with increasing concentration of particles can result from a redistribution of counterions that reduces electrostatic pressure. A linearized approximation for the electrostatic pressure, which proves remarkably accurate, provides physical insight and greatly eases numerical calculations for practical applications. Comparing with experiments, we explain why soft particles in deionized suspensions deswell upon increasing concentration and why this effect may be suppressed at higher ionic strength. The failure of the uniform ideal-gas approximation to adequately account for counterion-induced deswelling below close packing of microgels is attributed to neglect of spatial variation of the counterion density profile and the electrostatic pressure of incompletely neutralized macroions.

Solid state ionics: a Japan perspective

Science.gov (United States)

Yamamoto, Osamu

2017-12-01

The 70-year history of scientific endeavor of solid state ionics research in Japan is reviewed to show the contribution of Japanese scientists to the basic science of solid state ionics and its applications. The term 'solid state ionics' was defined by Takehiko Takahashi of Nagoya University, Japan: it refers to ions in solids, especially solids that exhibit high ionic conductivity at a fairly low temperature below their melting points. During the last few decades of exploration, many ion conducting solids have been discovered in Japan such as the copper-ion conductor Rb4Cu16I7Cl13, proton conductor SrCe1-xYxO3, oxide-ion conductor La0.9Sr0.9Ga0.9Mg0.1O3, and lithium-ion conductor Li10GeP2S12. Rb4Cu16I7Cl13 has a conductivity of 0.33 S cm-1 at 25 °C, which is the highest of all room temperature ion conductive solid electrolytes reported to date, and Li10GeP2S12 has a conductivity of 0.012 S cm-1 at 25 °C, which is the highest among lithium-ion conductors reported to date. Research on high-temperature proton conducting ceramics began in Japan. The history, the discovery of novel ionic conductors and the story behind them are summarized along with basic science and technology.

Ionic liquid marbles.

Science.gov (United States)

Gao, Lichao; McCarthy, Thomas J

2007-10-09

Liquid marbles have been reported during this decade and have been argued to be potentially useful for microfluidic and lab-on-a-chip applications. The liquid marbles described to date have been composed of either water or glycerol as the liquid and hydrophobized lycopodium or silica as the stabilizing particles. Both of these components are potentially reactive and do not permit the use of organic chemistry; the liquids are volatile. We report the use of perfluoroalkyl particles (oligomeric (OTFE) and polymeric (PTFE) tetrafluoroethylene, which are unreactive) to support/stabilize a range of ionic liquid marbles. Ionic liquids are not volatile and have been demonstrated to be versatile solvents for chemical transformations. Water marbles prepared with OTFE are much more robust than those prepared with hydrophobized lycopodium or silica.

Multiscale response of ionic systems to a spatially varying electric field

Directory of Open Access Journals (Sweden)

Jesper Schmidt Hansen

2017-05-01

Full Text Available In this paper the response of ionic systems subjected to a spatially varying electric field is studied. Following the Nernst-Planck equation, two forces driving the mass flux are present, namely, the concentration gradient and the electric potential gradient. The mass flux due to the concentration gradient is modelled through Fick's law, and a new constitutive relation for the mass flux due to the potential gradient is proposed. In the regime of low screening the response function due to the potential gradient is closely related to the ionic conductivity. In the large screening regime, on the other hand, the response function is governed by the charge-charge structure. Molecular dynamics simulations are conducted and the two wave vector dependent response functions are evaluated for models of a molten salt and an ionic liquid. In the low screening regime the response functions show same wave vector dependency, indicating that it is the same underlying physical processes that govern the response. In the screening regime the wave vector dependency is very different and, thus, the overall response is determined by different processes. This is in agreement with the observed failure of the Nernst-Einstein relation.

Determination of proton conductivity of ionic liquids for fuel cell applications

Energy Technology Data Exchange (ETDEWEB)

Wallnofer, E.; Baumgartner, W.R.; Hacker, V. [Graz Univ. of Technology, Graz (Austria). Inst. for Chemistry and Technology of Inorganic Material

2006-07-01

Hydrogen fuel cells operating at temperatures of between 100 and 200 degrees C allow the catalyst to tolerate higher levels of carbon monoxide (CO) impurities. However, the number of possible materials for high temperature fuel cell electrolytes or membranes is limited. This study examined the relevant electrochemical properties of different ion liquids with specific reference to neutralized imidazole derivates with a dominant Grotthuss mechanism of proton conduction. The electrochemical stability of the ionic liquids was measured by cyclic voltammetry (CV) under nitrogen. Proton conductivity was measured under hydrogen by CV within the electrochemical limits. Hydrogen was dissolved at the anode, transported through the ionic liquid, and recombined at the cathode, so that the detected current could indicate the amount of transported hydrogen. Electrochemical impedance spectroscopy (EIS) was used to measure the frequency dependent behaviour of the ionic liquids. All measurements were conducted at 50, 100, and 150 degrees C. Results of the study showed that proton conductivity increased with higher temperatures. It was concluded that neutralized imidazole derivates with optimized side chains of the cation may prove to be a viable alternative to conventional fuel cell electrolytes. 4 refs., 2 figs.

Vaporization enthalpies of imidazolium based ionic liquids. A thermogravimetric study of the alkyl chain length dependence

International Nuclear Information System (INIS)

Verevkin, Sergey P.; Zaitsau, Dzmitry H.; Emel’yanenko, Vladimir N.; Ralys, Ricardas V.; Yermalayeu, Andrei V.; Schick, Christoph

2012-01-01

Highlights: ► Enthalpies of vaporization of ionic liquids were measured with thermogravimetry. ► We studied 1-alkyl-3-methyl-imidazolium bis(trifluoromethanesulfonyl)imide. ► The linear alkyl chain length was 4, 6, 8, 10, 12, 14, 16, and 18 C-atoms. ► A linear dependence on the chain length of the alkyl-imidazolium cation was found. - Abstract: Vaporization enthalpies for a series of ten ionic liquids (ILs) 1-alkyl-3-methyl-imidazolium bis(trifluoromethanesulfonyl)imide [C n mim][NTf 2 ], with the alkyl chain length n = 4, 6, 8, 10, 12, 14, 16, and 18 were determined using the thermogravimetric method. An internally consistent set of experimental data and vaporization enthalpies at 540 K was obtained. Vaporization enthalpies at 540 K have shown a linear dependence on the chain length of the alkyl-imidazolium cation in agreement with the experimental results measured previously with a quartz crystal microbalance. Ambiguity of Δ l g C pm o -values required for the extrapolation of experimental vaporization enthalpies to the reference temperature 298 K has been discussed.

Ionic interactions in biological and physical systems: a variational treatment.

Science.gov (United States)

Eisenberg, Bob

2013-01-01

Chemistry is about chemical reactions. Chemistry is about electrons changing their configurations as atoms and molecules react. Chemistry has for more than a century studied reactions as if they occurred in ideal conditions of infinitely dilute solutions. But most reactions occur in salt solutions that are not ideal. In those solutions everything (charged) interacts with everything else (charged) through the electric field, which is short and long range extending to the boundaries of the system. Mathematics has recently been developed to deal with interacting systems of this sort. The variational theory of complex fluids has spawned the theory of liquid crystals (or vice versa). In my view, ionic solutions should be viewed as complex fluids, particularly in the biological and engineering context. In both biology and electrochemistry ionic solutions are mixtures highly concentrated (to approximately 10 M) where they are most important, near electrodes, nucleic ids, proteins, active sites of enzymes, and ionic channels. Ca2+ is always involved in biological solutions because the concentration (really free energy per mole) of Ca2+ in a particular location is the signal that controls many biological functions. Such interacting systems are not simple fluids, and it is no wonder that analysis of interactions, such as the Hofmeister series, rooted in that tradition has not succeeded as one would hope. Here, we present a variational treatment of ard spheres in a frictional dielectric with the hope that such a treatment of an lectrolyte as a complex fluid will be productive. The theory automatically extends to spatially nonuniform boundary conditions and the nonequilibrium systems and flows they produce. The theory is unavoidably self-consistent since differential equations are derived (not assumed) from models of (Helmholtz free) nergy and dissipation of the electrolyte. The origin of the Hofmeister series is (in my view) an inverse problem that becomes well posed when

Synergistic extraction of europium(III) in ammonium ionic liquid

International Nuclear Information System (INIS)

Rout, Alok; Venkatesan, K.A.; Antony, M.P.

2016-01-01

Room temperature ionic liquids have been receiving increased attention for possible applications in the area of nuclear fuel reprocessing and waste management due to their fascinating properties such as good ionicity, high solvation capability, properties tunable etc. Most of the studies in the literature on the extraction of metal ions with molecular extractants dissolved in ionic liquid diluents are making use of the hydrophobic ionic liquids containing imidazolium cations such as the 1-alkyl-3-methylimidazolium ion. From an environmental point of view, such ionic liquids are not suitable as the primary mode of the metal extraction is by cation exchange mechanism wherein ionic liquid cation is lost to the aqueous phase leading to aqueous contamination and issue of recyclability of organic phase. However, there are some hydrophobic ionic liquids such as trioctylmethylammonium chloride ((N 1888 )(Cl)), and trihexyl(tetradecyl)phoshonium chloride (Cyphos IL 101) that exhibit no cation exchange in the aqueous phase during extraction. In this context, the extraction behavior of europium(III) using a neutral extractant, octyl, phenyl-N.N-diisobutylmethylcarbamoylphophinoxide (CMPO) and/or an acidic extractant bis(ethylhexyl)phosphoric acid (D2EHPA) dissolved in the ammonium ionic liquid diluent, trioctylmethylammonium bis(trifluoromethanesulfonyl)imide, (N 1888 )(NTf 2 ). The extraction behavior of CMPO (or D2EHPA)/(N 1888 )((Tf 2 ) system was investigated as a function of different extraction parameters such as feed acidity, extractant concentration, equilibration time etc.

Preparation and transport properties of novel lithium ionic liquids

International Nuclear Information System (INIS)

Shobukawa, Hitoshi; Tokuda, Hiroyuki; Tabata, Sei-Ichiro; Watanabe, Masayoshi

2004-01-01

Novel lithium salts of borates having two electron-withdrawing groups (either 1,1,1,3,3,3-hexafluoro-2-propoxy or pentafluorophenoxy group) and two methoxy-oligo(ethylene oxide) groups (number of repeating unit: n = 3, 4, 7.2) were prepared by successive substitution-reactions from LiBH 4 . The obtained lithium salts were clear and colorless liquids at room temperature. The density, thermal property, viscosity, and ionic conductivity were measured for the lithium ionic liquids. The pulsed-gradient spin-echo NMR (PGSE-NMR) method was used to independently determine self-diffusion coefficients of the lithium cation ( 7 Li NMR) and the anion ( 19 F NMR) in the bulk. The ionic conductivity of the new lithium salts was 10 -5 to 10 -4 S cm -1 at 30 deg. C, which was lower than that of typical ionic liquids by two orders of magnitude. However, the degree of self-dissociation of the lithium ionic liquids; the ratio of the molar conductivity determined by the complex impedance method to that calculated from the self-diffusion coefficients and the Nernst-Einstein equation, ranged from 0.1 to 0.4, which are comparable values to those of a highly dissociable salt in an aprotic polar solvent and of typical ionic liquids. The main reason for the meager conductivity was high viscosities of the lithium ionic liquids. It should be noted that the lithium ionic liquids have self-dissociation ability and conduct the ions in the absence of organic solvents

Aqueous solutions of ionic liquids: microscopic assembly

NARCIS (Netherlands)

Vicent-Luna, J.M.; Dubbeldam, D.; Gómez-Álvarez, P.; Calero, S.

2016-01-01

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

Ionic Liquid Catalyzed Electrolyte for Electrochemical Polyaniline Supercapacitors

Science.gov (United States)

Inamdar, A. I.; Im, Hyunsik; Jung, Woong; Kim, Hyungsang; Kim, Byungchul; Yu, Kook-Hyun; Kim, Jin-Sang; Hwang, Sung-Min

2013-05-01

The effect of different wt.% of ionic liquid "1,6-bis (trimethylammonium-1-yl) hexane tetrafluoroborate" in 0.5 M LiClO4+PC electrolyte on the supercapacitor properties of polyaniline (PANI) thin film are investigated. The PANI film is synthesized using electropolymerization of aniline in the presence of sulfuric acid. The electrochemical properties of the PANI thin film are studied by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) measurements. The optimum amount of the ionic liquid is found to be 2 wt.% which provides better ionic conductivity of the electrolyte. The highest specific capacitance of 259 F/g is obtained using the 2 wt.% electrolyte. This capacitance remains at up to 208 F/g (80% capacity retention) after 1000 charge-discharge cycles at a current density of 0.5 mA/g. The PANI film in the 2 wt.% ionic liquid catalyzed 0.5 M LiClO4+PC electrolyte shows small electrochemical resistance, better rate performance and higher cyclability. The increased ionic conductivity of the 2 wt.% ionic liquid catalyzed electrolyte causes a reduction in resistance at the electrode/electrolyte interface, which can be useful in electrochemically-preferred power devices for better applicability.

Method for enhancing the thermal stability of ionic compounds

DEFF Research Database (Denmark)

2013-01-01

This invention relates to a method for enhancing the thermal stability of ionic compounds including ionic liquids, by immobilization on porous solid support materials having a pore diameter of between about 20-200 AA, wherein the solid support does not have a pore size of 90 AA.......This invention relates to a method for enhancing the thermal stability of ionic compounds including ionic liquids, by immobilization on porous solid support materials having a pore diameter of between about 20-200 AA, wherein the solid support does not have a pore size of 90 AA....

Ionic systems in materials research : new materials and processes based on ionic polymerizations and/or ionic liquids

NARCIS (Netherlands)

Guerrero-Sanchez, C.A.

2007-01-01

Systems based on ionic interactions are usually related to reversible processes and/or transitory chemical states and, nowadays, they are believed to be key factors for the understanding and for the development of processes in several branches of chemistry and materials research. During the last

Using ethane and butane as probes to the molecular structure of 1-alkyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl] imide ionic liquids.

Science.gov (United States)

Costa Gomes, Margarida F; Pison, Laure; Pensado, Alfonso S; Pádua, Agilio A H

2012-01-01

In this work, we have studied the solubility and the thermodynamic properties of solvation, between 298 and 343 K and at pressures close to atmospheric, of ethane and n-butane in several ionic liquids based on the bis[(trifluoromethyl) sulfonyl]imide anion and on 1-alkyl-3-methylimidazolium cations, [CnC1Im] [NTf2], with alkyl side-chains varying from two to ten carbon atoms. The solubility of butane is circa one order of magnitude larger than that of ethane with mole fractions as high as 0.15 in [C10C1Im][NTf2] at 300 K. The solubilities of both n-butane and ethane gases are higher for ionic liquids with longer alkyl chains. The behaviour encountered is explained by the preferential solvation of the gases in the non-polar domains of the solvents, the larger solubility of n-butane being attributed to the dispersive contributions to the interaction energy. The rise in solubility with increasing size of the alkyl-side chain is explained by a more favourable entropy of solvation in the ionic liquids with larger cations. These conclusions are corroborated by molecular dynamics simulation studies.

Selective ionic liquid ferrofluid based dispersive-solid phase extraction for simultaneous preconcentration/separation of lead and cadmium in milk and biological samples.

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Fasih Ramandi, Negin; Shemirani, Farzaneh

2015-01-01

For the first time, a selective ionic liquid ferrofluid has been used in dispersive solid phase extraction (IL-FF-D-SPE) for simultaneous preconcentration and separation of lead and cadmium in milk and biological samples combined with flame atomic absorption spectrometry. To improve the selectivity of the ionic liquid ferrofluid, the surface of TiO2 nanoparticles with a magnetic core as sorbent was modified by loading 1-(2-pyridylazo)-2-naphtol. Due to the rapid injection of an appropriate amount of ionic liquid ferrofluid into the aqueous sample by a syringe, extraction can be achieved within a few seconds. In addition, based on the attraction of the ionic liquid ferrofluid to a magnet, no centrifugation step is needed for phase separation. The experimental parameters of IL-FF-D-SPE were optimized using a Box-Behnken design (BBD) after a Plackett-Burman screening design. Under the optimum conditions, the relative standard deviations of 2.2% and 2.4% were obtained for lead and cadmium, respectively (n=7). The limit of detections were 1.21 µg L(-1) for Pb(II) and 0.21 µg L(-1) for Cd(II). The preconcentration factors were 250 for lead and 200 for cadmium and the maximum adsorption capacities of the sorbent were 11.18 and 9.34 mg g(-1) for lead and cadmium, respectively. Copyright © 2014 Elsevier B.V. All rights reserved.

A comparative evaluation of different ionic liquids for arsenic species separation and determination in wine varietals by liquid chromatography - hydride generation atomic fluorescence spectrometry.

Science.gov (United States)

Castro Grijalba, Alexander; Fiorentini, Emiliano F; Martinez, Luis D; Wuilloud, Rodolfo G

2016-09-02

The application of different ionic liquids (ILs) as modifiers for chromatographic separation and determination of arsenite [As(III)], arsenate [As(V)], dimethylarsonic acid (DMA) and monomethylarsonic acid (MMA) species in wine samples, by reversed-phase high performance liquid chromatography coupled to hydride generation atomic fluorescence spectrometry detection (RP-HPLC-HG-AFS) was studied in this work. Several factors influencing the chromatographic separation of the As species, such as pH of the mobile phase, buffer solution concentration, buffer type, IL concentration and length of alkyl groups in ILs were evaluated. The complete separation of As species was achieved using a C18 column in isocratic mode with a mobile phase composed of 0.5% (v/v) 1-octyl-3-methylimidazolium chloride ([C8mim]Cl) and 5% (v/v) methanol at pH 8.5. A multivariate methodology was used to optimize the variables involved in AFS detection of As species after they were separated by HPLC. The ILs showed remarkable performance for the separation of As species, which was obtained within 18min with a resolution higher than 0.83. The limits of detection for As(III), As(V), MMA and DMA were 0.81, 0.89, 0.62 and 1.00μg As L(-1). The proposed method was applied for As speciation analysis in white and red wine samples originated from different grape varieties. Copyright © 2016 Elsevier B.V. All rights reserved.

Soft ionization of thermally evaporated hypergolic ionic liquid aerosols

Energy Technology Data Exchange (ETDEWEB)

University of California; ERC, Incorporated, Edwards Air Force Base; Air Force Research Laboratory, Edwards Air Force Base; National Synchrotron Radiation Research Center (NSRRC); Institute of Chemistry, Hebrew University; Koh, Christine J.; Liu, Chen-Lin; Harmon, Christopher W.; Strasser, Daniel; Golan, Amir; Kostko, Oleg; Chambreau, Steven D.; Vaghjiani, Ghanshyam L.; Leone, Stephen R.

2011-07-19

Isolated ion pairs of a conventional ionic liquid, 1-Ethyl-3-Methyl-Imidazolium Bis(trifluoromethylsulfonyl)imide ([Emim+][Tf2N?]), and a reactive hypergolic ionic liquid, 1-Butyl-3-Methyl-Imidazolium Dicyanamide ([Bmim+][Dca?]), are generated by vaporizing ionic liquid submicron aerosol particles for the first time; the vaporized species are investigated by dissociative ionization with tunable vacuum ultraviolet (VUV) light, exhibiting clear intact cations, Emim+ and Bmim+, presumably originating from intact ion pairs. Mass spectra of ion pair vapor from an effusive source of the hypergolic ionic liquid show substantial reactive decomposition due to the internal energy of the molecules emanating from the source. Photoionization efficiency curves in the near threshold ionization region of isolated ion pairs of [Emim+][Tf2N?]ionic liquid vapor are compared for an aerosol source and an effusive source, revealing changes in the appearance energy due to the amount of internal energy in the ion pairs. The aerosol source has a shift to higher threshold energy (~;;0.3 eV), attributed to reduced internal energy of the isolated ion pairs. The method of ionic liquid submicron aerosol particle vaporization, for reactive ionic liquids such as hypergolic species, is a convenient, thermally ?cooler? source of isolated intact ion pairs in the gas phase compared to effusive sources.

Lattice mechanics of ionic crystals - unified study

International Nuclear Information System (INIS)

Sengupta, S.; Roy, D.; Basu, A.N.

1979-01-01

The up-to-date situation in the understanding of the mechanical properties of ionic solids is reviewed. These properties are determined by the Born-Oppenheimer (B-O) potential energy function. For ionic crystals this potential energy function can be written down with some precision. To keep the expression tractable, the dominant electron deformation, the dipolar deformation, is treated as an adiabatic variable and the energy then becomes a function of both the nuclear coordinates and the ionic dipole moments. All the well known models for ionic crystals are discussed in terms of the energy expression they imply. This makes the comparison straight forward and brings out the essential difference between the models clearly. Next various quantum mechanical treatments for ionic crystals are reviewed. An attempt is made to obtain the B-O potential energy expression using a Heitler-London approach. By comparing the various models one can arrive at some definitive conclusions about the degree of validity and the assumptions underlying these models. Finally a comprehensive review of the results of actual computation on various ionic crystals done by different authors is undertaken. The crucial quantitative results are examined and the success and shortcoming of each calculation are critically analysed. The guiding principle in this part is the unified approach. i.e. to see how far a model with a given set of parameters accounts for both the dynamic and static properties. The discussion is divided in three sections for crystals with sodium chloride, cesium chloride and zinc sulfide structures. Outstanding problems and difficulties in the present understanding are pointed out. (auth.)

Aerobic, catalytic oxidation of alcohols in ionic liquids

Directory of Open Access Journals (Sweden)

Souza Roberto F. de

2006-01-01

Full Text Available An efficient and simple catalytic system based on RuCl3 dissolved in ionic liquids has been developed for the oxidation of alcohols into aldehydes and ketones under mild conditions. A new fluorinated ionic liquid, 1-n-butyl-3-methylimidazolium pentadecafluorooctanoate, was synthesized and demonstrated better performance that the other ionic liquids employed. Moreover this catalytic system utilizes molecular oxygen as an oxidizing agent, producing water as the only by-product.

He atom-surface scattering: Surface dynamics of insulators, overlayers and crystal growth

International Nuclear Information System (INIS)

1992-01-01

Investigations in this laboratory have focused on the surface structure and dynamics of ionic insulators and on epitaxial growth onto alkali halide crystals. In the later the homoepitaxial growth of NaCl/NaCl(001) and the heteroepitaxial growth of KBr/NaCl(001), NaCl/KBr(001) and KBr/RbCl(001) have been studied by monitoring the specular He scattering as a function of the coverage and by measuring the angular and energy distributions of the scattered He atoms. These data provide information on the surface structure, defect densities, island sizes and surface strain during the layer-by-layer growth. The temperature dependence of these measurements also provides information on the mobilities of the admolecules. He atom scattering is unique among surface probes because the low-energy, inert atoms are sensitive only to the electronic structure of the topmost surface layer and are equally applicable to all crystalline materials. It is proposed for the next year to exploit further the variety of combinations possible with the alkali halides in order to carry out a definitive study of epitaxial growth in the ionic insulators. The work completed so far, including measurements of the Bragg diffraction and surface dispersion at various stages of growth, appears to be exceptionally rich in detail, which is particularly promising for theoretical modeling. In addition, because epitaxial growth conditions over a wide range of lattice mismatches is possible with these materials, size effects in growth processes can be explored in great depth. Further, as some of the alkali halides have the CsCl structure instead of the NaCl structure, we can investigate the effects of the heteroepitaxy with materials having different lattice preferences. Finally, by using co-deposition of different alkali halides, one can investigate the formation and stability of alloys and even alkali halide superlattices

Simultaneous Design of Ionic Liquids and Azeotropic Separation Processes

DEFF Research Database (Denmark)

Roughton, Brock C.; White, John; Camarda, Kyle V.

2011-01-01

A methodology for the design of azeotrope separation processes using ionic liquids as entrainers is outlined. A Hildebrand solubility parameter group contribution model has been developed to screen for or design an ionic liquid entrainer that is soluble with the azeotropic components. Using the b...... % [BMPy][BF4] added. The driving force concept is used to design an extractive distillation process that minimizes energy inputs. The methodology given can be expanded to the use of ionic liquids as entrainers in any azeotropic system of interest.......A methodology for the design of azeotrope separation processes using ionic liquids as entrainers is outlined. A Hildebrand solubility parameter group contribution model has been developed to screen for or design an ionic liquid entrainer that is soluble with the azeotropic components. Using...

Protic Cationic Oligomeric Ionic Liquids of the Urethane Type

DEFF Research Database (Denmark)

Shevchenko, V. V.; Stryutsky, A. V.; Klymenko, N. S.

2014-01-01

Protic oligomeric cationic ionic liquids of the oligo(ether urethane) type are synthesized via the reaction of an isocyanate prepolymer based on oligo(oxy ethylene)glycol with M = 1000 with hexamethylene-diisocyanate followed by blocking of the terminal isocyanate groups with the use of amine...... derivatives of imidazole, pyridine, and 3-methylpyridine and neutralization of heterocycles with ethanesulfonic acid and p-toluenesulfonic acid. The structures and properties of the synthesized oligomeric ionic liquids substantially depend on the structures of the ionic groups. They are amorphous at room...... temperature, but ethanesulfonate imidazolium and pyridinium oligomeric ionic liquids form a low melting crystalline phase. The proton conductivities of the oligomeric ionic liquids are determined by the type of cation in the temperature range 80-120 degrees C under anhydrous conditions and vary within five...

Tuning the electronic structure of graphene through alkali metal and halogen atom intercalation

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Ahmad, Sohail; Miró, Pere; Audiffred, Martha; Heine, Thomas

2018-04-01

The deposition, intercalation and co-intercalation of heavy alkali metals and light halogens atoms in graphene mono- and bilayers have been studied using first principles density-functional calculations. Both the deposition and the intercalation of alkali metals gives rise to n-type doping due to the formation of M+-C- pairs. The co-intercalation of a 1:1 ratio of alkali metals and halogens derives into the formation of ionic pairs among the intercalated species, unaltering the electronic structure of the layered material.

Fast Conversion of Ionic Liquids and Poly(Ionic Liquid)s into Porous Nitrogen-Doped Carbons in Air.

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