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Sample records for polymeric ionic exchangers

  1. Novel polymeric ionic liquid microspheres with high exchange capacity for fast extraction of plasmid DNA.

    PubMed

    Wang, Xiaofeng; Xing, Ligang; Shu, Yang; Chen, Xuwei; Wang, Jianhua

    2014-07-21

    A novel polymeric ionic liquid (PIL) microsphere, poly(1-vinyl-3-(2-methoxy-2-oxyl ethyl)imidazolium) hexafluorophosphate, is prepared via W/O emulsion polymerization. Rapid ion-exchange between the anionic moieties of PIL and DNA fragments is demonstrated facilitating the exchange equilibrium to be reached within 1 min. The PIL microspheres exhibit a high capacity of 190.7 μg mg(-1) for DNA adsorption. A fast DNA isolation protocol is thus developed with the PIL microspheres as solid phase adsorbent. It is feasible to facilitate DNA adsorption or stripping from the microspheres by simply regulating the concentration of salt. DNA adsorption is facilitated at low salt concentration, while higher concentration of salt entails DNA recovery from the microspheres. In practice, the retained DNA could be readily recovered with 1.0 mol L(-1) NaCl as stripping reagent, giving rise to a recovery of ca. 80.7%. The PIL microspheres are used for the adsorption/isolation of plasmid DNA from E. coli cell culture, demonstrating a superior adsorption performance with respect to that achieved by a commercial Plasmid Miniprep Kit.

  2. Facile modification of multi-walled carbon nanotubes-polymeric ionic liquids-coated solid-phase microextraction fibers by on-fiber anion exchange.

    PubMed

    Feng, Juanjuan; Sun, Min; Bu, Yanan; Luo, Chuannan

    2015-05-01

    In situ anion exchange has been proved to be an efficient method for facile modification of polymeric ionic liquids (PILs)-based stationary phases. In this work, an on-fiber anion exchange process was utilized to tune the extraction performance of a multi-walled carbon nanotubes (MWCNTs)-poly(1-vinyl-3-octylimidazolium bromide) (poly(VOIm(+)Br(-)))-coated solid-phase microextraction (SPME) fiber. MWCNTs were first coated onto the stainless steel wire through a layer-by-layer fabrication method and then the PILs were coated onto the MWCNTs physically. Anion of the MWCNTs-poly(VOIm(+)Br(-)) fiber was changed into bis(triflroromethanesulfonyl)imide (NTf2(-)) and 2-naphthalene-sulfonate (NapSO3(-)) by on-fiber anion exchange. Coupled to gas chromatography, the MWCNTs-poly(VOIm(+)Br(-)) fiber showed acceptable extraction efficiency for hydrophilic and hydrogen-bonding-donating alcohols, with limits of detection (LODs) in the range of 0.005-0.05μgmL(-1); after the anion exchange with NTf2(-), the obtained MWCNTs-poly(VOIm(+)NTf2(-)) fiber brought wide linear ranges for hydrophobic n-alkanes with correlation coefficient (R) ranging from 0.994 to 0.997; aromatic property of the fiber was enhanced by aromatic NapSO3(-) anions to get sufficient extraction capacity for phthalate esters and halogenated aromatic hydrocarbons. The MWCNTs-poly(VOIm(+)NapSO3(-)) fiber was finally applied to determine several halogenated aromatic hydrocarbons in groundwater of industrial park.

  3. Sulfonated Polymerized Ionic Liquid Block Copolymers.

    PubMed

    Meek, Kelly M; Elabd, Yossef A

    2016-07-01

    The successful synthesis of a new diblock copolymer, referred to as sulfonated polymerized ionic liquid (PIL) block copolymer, poly(SS-Li-b-AEBIm-TFSI), is reported, which contains both sulfonated blocks (sulfonated styrene: SS) and PIL blocks (1-[(2-acryloyloxy)ethyl]-3-butylimidazolium: AEBIm) with both mobile cations (lithium: Li(+) ) and mobile anions (bis(trifluoromethylsulfonyl)imide: TFSI(-) ). Synthesis consists of polymerization via reversible addition-fragmentation chain transfer, followed by post-functionalization reactions to covalently attach the imidazolium cations and sulfonic acid anions to their respective blocks, followed by ion exchange metathesis resulting in mobile Li(+) cations and mobile TFSI(-) anions. Solid-state films containing 1 m Li-TFSI salt dissolved in ionic liquid result in an ion conductivity of >1.5 mS cm(-1) at 70 °C, where small-angle X-ray scattering data indicate a weakly ordered microphase-separated morphology. These results demonstrate a new ion-conducting block copolymer containing both mobile cations and mobile anions. PMID:27125600

  4. Ionic conductance behavior of polymeric gel electrolyte containing ionic liquid mixed with magnesium salt

    NASA Astrophysics Data System (ADS)

    Morita, Masayuki; Shirai, Takahiro; Yoshimoto, Nobuko; Ishikawa, Masashi

    A new polymeric gel electrolyte system conducting magnesium ion has been proposed. The gel electrolytes consisted of poly(ethylene oxide)-modified polymethacrylate (PEO-PMA) dissolving ionic liquid mixed with magnesium salt, Mg[(CF 3SO 2) 2N] 2. The polymeric gel films were self-standing, transparent and flexible with enough mechanical strength. The ionic conductance and the electrochemical properties of the gel films were investigated. Thermal analysis results showed that the polymeric gel is homogeneous and amorphous over a wide temperature range. The highest conductivity, 1.1 × 10 -4 S cm -1 at room temperature (20 °C), was obtained for the polymeric gel containing 50 wt.% of the ionic liquid in which the content of the magnesium salt was 20 mol%. The dc polarization of a Pt/Mg cell using the polymeric gel electrolyte proved that the magnesium ion (Mg 2+) is mobile in the present polymeric system.

  5. Accurate fluorescent polymeric thermometers containing an ionic component.

    PubMed

    Gota, Chie; Uchiyama, Seiichi; Ohwada, Tomohiko

    2007-02-01

    Fluorescent polymeric thermometers consisting of only N-alkylacrylamide and fluorescent components show rather low temperature resolution in their functional ranges (ca. 15-50 degrees C) because of the occurrence of intermolecular aggregation, which causes hysteresis in their fluorescence response to changes in temperature. By adding an ionic component to prevent such intermolecular aggregation, we obtained four fluorescent polymeric thermometers that offer high temperature resolution (<0.2 degrees C). Each new fluorescent polymeric thermometer covered the temperature range, 9-33 degrees C, 30-51 degrees C, 49-66 degrees C or 4-38 degrees C.

  6. Recent advances of ionic liquids and polymeric ionic liquids in capillary electrophoresis and capillary electrochromatography.

    PubMed

    Tang, Sheng; Liu, Shujuan; Guo, Yong; Liu, Xia; Jiang, Shengxiang

    2014-08-29

    Ionic liquids (ILs) and polymeric ionic liquids (PILs) with unique and fascinating properties have drawn considerable interest for their use in separation science, especially in chromatographic techniques. In this article, significant contributions of ILs and PILs in the improvement of capillary electrophoresis and capillary electrochromatography are described, and a specific overview of the most relevant examples of their applications in the last five years is also given. Accordingly, some general conclusions and future perspectives in these areas are discussed.

  7. Correlating morphology to dc conductivity in polymerized ionic liquids

    NASA Astrophysics Data System (ADS)

    Iacob, Ciprian; Matusmoto, Atsushi; Inoue, Tadashi; Runt, James

    Polymerized ionic liquids (PILs) combine the attractive mechanical characteristics of polymers and unique physico-chemical properties of low molecular weight ionic liquids in the same material. PILs have shown remarkable advantages when employed in electrochemical devices such as dye-sensitized solar cells and lithium batteries, among others. Understanding their ionic transport mechanism is the key for designing highly conductive PILs. In the current study, the correlation between morphology and charge transport in two homologous series of PILs with systematic variation of the alkyl chain length and anions is investigated using broadband dielectric spectroscopy, rheology, differential scanning calorimetry and X-ray scattering. As the alkyl chain length increases, the backbone-to-backbone separation increases, and dc-conductivity consequently decreases. The cations dominate structural dynamics since they are attached to the polymer chains, while the anions are smaller and more mobile ionic species thereby controlling the ionic conductivity. Further interpretation of decoupling of dc conductivity from the segmental relaxation enabled the correlation between polymer morphology and dc conductivity. Supported by the National Science Foundation, Polymers Program.

  8. Ionic polymeric conductor nanocomposites (IPCNCs) as distributed nanosensors and nanoactuators.

    PubMed

    Shahinpoor, Mohsen

    2008-09-01

    This paper covers advances made in connection with ionic polymeric conductor nanocomposites (IPCNCs) as distributed biomimetic nanosensors, nanoactuators, nanorobots and artificial muscles. A review of the fundamental properties and characteristics of IPCNCs will be presented first. This summary will include descriptions of the basic materials' molecular structure and subsequent procedure to manufacture the basic material for chemical plating and electroactivation. Further described are chemical molecular plating technologies to make IPCNCs; nanotechnologies of manufacturing and trapping of nanoparticles; SEM, TEM, SPM and AFM characterization of IPMNCs; biomimetic sensing and actuation characterization techniques; electrical characterization; and equivalent circuit modeling of IPCNCs as electronic materials. A phenomenological model of the underlying sensing and actuation mechanisms is also presented based on linear irreversible thermodynamics with two driving forces, an electric field and a solvent pressure gradient and two fluxes, electric current density and the ionic+solvent flux.

  9. Irreversible thermochromic behavior in gold and silver nanorod/polymeric ionic liquid nanocomposite films.

    PubMed

    Tollan, Christopher M; Marcilla, Rebeca; Pomposo, Jose A; Rodriguez, Javier; Aizpurua, Javier; Molina, Jon; Mecerreyes, David

    2009-02-01

    The novel application of gold and silver nanorods as irreversible thermochromic dyes in polymeric ionic liquid (PIL) nanocomposites is proposed here. These materials have been synthesized by anion exchange of an imidazolium-based PIL in a solution that also contained gold nanorods. This resulted in the entrapment of the nanoobjects within a solid polymer precipitate. In this article, the effect of the temperature was studied in relation to the change of shape and, consequently, color of the gold or silver nanorods within the films. For the nanocomposites studied here, a maximum of two visual thermochromic transitions was observed for gold nanorods and up to three transitions were observed for silver nanorods.

  10. Electrically induced dynamic contraction of ionic polymeric gels

    NASA Astrophysics Data System (ADS)

    Shahinpoor, Mohsen; Osada, Yoshihito

    1995-05-01

    An analytical model is presented for the dynamics of contraction of ionic polymeric gels with liquid exudation in the presence of an electrical field. The proposed model considers the dynamic balance between the internal forces during the contraction. These forces are assumed to be due to the viscous effects caused by the motion of the liquid, the inertial forces due to the motion of the liquid in and out of the network, and the electrophoretic forces due to the motion of the charged ions in the solvent as it exudes from the ionic polymeric gel network. The effects of rubber elasticity of the network as well as ion-ion interactions have been assumed negligible in this case compared with the inertial, viscous, and electrophoretic effects. The governing equations, thus obtained, are then solved exactly for the velocity of liquid exudation from within the network as a function of time and radial distance in cylindrical samples. The relative weight of the gel sample is then related to this velocity by an integral equation. This integral equation is then numerically solved to obtain a relationship between the amount of contraction as a function of time, electric field strength, and other pertinent material and geometrical parameters. The results of the numerical simulations are compared with some experimental results on PAMPS contractile fibers and satisfactory agreements are observed.

  11. Versatile cation transport in imidazolium based polymerized ionic liquids

    NASA Astrophysics Data System (ADS)

    Evans, Christopher; Segalman, Rachel

    Polymerized ionic liquids (PIL) with tethered imidazolium groups are able to conduct a diverse array of cations relevant for energy applications. The well-known complexation of imidazolium with transition metals is exploited to bind ions such as H +, Li+, Cu2+, and Ni2+ by doping the neutral PIL with the appropriate Cation-TFSI- salt. Conductivities were first determined via AC impedance indicating that H+ salts lead to the highest conductivity (due to low ion mass and potential Grotthus mechanism) followed by Cu2+, Li+, Ag+, and Ni2+. The equilibrium constant for imidazolium complexation is larger for Cu2+ relative to Li-, Ag-, and Ni-imidazolium complexes leading to greater salt dissociation and higher conductivities. For LiTFSI and CuTFSI2 salts, metallic lithium or copper electrodes were employed in battery cells to pass a steady DC current and confirm that the cations are in fact carrying current. Interestingly, the divalent Cu2+ also ionically crosslinks the polymer leading to a plateau in the viscosity. Thus, divalent ions provide an unique route to high conductivity, high modulus polymeric electrolytes. Future studies involving ZnTFSI2 and MgTFSI2 for battery applications are proposed to examine how versatile the PIL platform is for cation transport.

  12. Anisotropic microporous supports impregnated with polymeric ion-exchange materials

    DOEpatents

    Friesen, Dwayne; Babcock, Walter C.; Tuttle, Mark

    1985-05-07

    Novel ion-exchange media are disclosed, the media comprising polymeric anisotropic microporous supports containing polymeric ion-exchange or ion-complexing materials. The supports are anisotropic, having small exterior pores and larger interior pores, and are preferably in the form of beads, fibers and sheets.

  13. Anisotropic microporous supports impregnated with polymeric ion-exchange materials

    DOEpatents

    Friesen, D.; Babcock, W.C.; Tuttle, M.

    1985-05-07

    Novel ion-exchange media are disclosed, the media comprising polymeric anisotropic microporous supports containing polymeric ion-exchange or ion-complexing materials. The supports are anisotropic, having small exterior pores and larger interior pores, and are preferably in the form of beads, fibers and sheets. 5 figs.

  14. Morphology and Ionic Conductivity of Humidity-Responsive Polymerized Ionic Liquid Block Copolymers

    NASA Astrophysics Data System (ADS)

    Sharick, Sharon; Meek, Kelly; Ye, Yuesheng; Elabd, Yossef A.; Winey, Karen I.

    2014-03-01

    We present the ionic conductivity and morphology of humidity-responsive polymerized ionic liquid block copolymers (PIL BCPs), poly(methyl methacrylate- b-1-[2-(methacryloyloxy)ethyl]-3-butylimidazolium-X), where X is a bromide (Br) or hydroxide (OH) anion, as a function of relative humidity (RH), temperature, and PIL composition (ϕPIL) . PIL BCPs were characterized by in situ small-angle X-ray scattering and electrochemical impedance spectroscopy. These PIL BCPs have microphase separated morphologies and long-range order increases as ϕPIL increases. Notably, ionic conductivity increases 3 to 4 orders of magnitude when RH increases from 30 to 90 percent. When ϕPIL is greater than 0.37, BCP ionic conductivity approaches or exceeds that of the homopolymer, suggesting that the dynamics in PIL microdomains mimic the homopolymer and long-range order aids ion transport. Moreover, over 60 percent of the BCP is nonconductive without a penalty in ion transport. When ϕPIL is less than 0.37, BCP conductivity is 1 to 2 orders of magnitude less than the homopolymer and non-conductive PMMA segments dominate ion transport, as expected. Ionic conductivities at 80 °C, 90 percent RH, are 7.6 mS/cm for the Br-containing BCP with ϕPIL = 0.53 and 25.0 mS/cm for the OH-containing BCP with ϕPIL = 0.50.

  15. Ionic Conductivity and Gas Permeability of Polymerized Ionic Liquid Block Copolymer Membranes

    NASA Astrophysics Data System (ADS)

    Evans, Christopher; Sanoja, Gabriel; Schneider, Yanika; Modestino, Miguel; Segalman, Rachel; Joint CenterArtificial Photosynthesis Team

    2014-03-01

    Polymer membranes for many energy applications, such as solar-to-hydrogen fuel production, require ionic conductivity while acting as gas diffusion barriers. We have synthesized a diblock copolymer consisting of poly(styrene-block-(4-(2-methacrylamidoethyl)-imidazolium trifluoroacetate) by treating poly(styrene-block-histamine methacrylamide) (PS- b-PHMA) with trifluoroacetic acid. The PS block serves as the structural support while the imidazolium derivative is an ion conducting polymerized ionic liquid (PIL). Small angle X-ray scattering and transmission electron microscopy demonstrate that the block copolymer self-assembles into well-ordered nanostructures, with lamellae and hexagonally packed cylindrical morphologies. The ionic conductivities of the PS-b-PHMA materials were as high as 2 x 10-4 S/cm while an order of magnitude increase in conductivity was observed upon conversion to PS-b-PIL. The ionic conductivity of the PS-b-PIL increased by a factor of ~ 4 up to 1.2 x 10-3 S/cm as the PIL domain size increased from 20 to 40 nm. These insights allow for the rational design of high performance ion conducting membranes with even greater conductivities via precise morphological control. Additionally, the role of thermal annealing on the ionic conductivity and gas permeability of copolymer membranes was investigated.

  16. Polymeric Ionic Networks with High Charge Density: Solid-like Electrolytes in Lithium Metal Batteries

    DOE PAGES

    Zhang, Pengfei; Li, Mingtao; Jiang, Xueguang; Fang, Youxing; Veith, Gabriel M.; Sun, Xiao-Guang; Dai, Sheng

    2015-11-02

    Polymerized ionic networks (PINs) with six ion pairs per repeating unit are synthesized by nucleophilic-substitution-mediated polymerization or radical polymerization of monomers bearing six 1-vinylimidazolium cations. PIN-based solid-like electrolytes show good ionic conductivities (up to 5.32 × 10-3 S cm-1 at 22 °C), wide electrochemical stability windows (up to 5.6 V), and good interfacial compatibility with the electrodes.

  17. Polymeric Ionic Networks with High Charge Density: Solid-like Electrolytes in Lithium Metal Batteries

    SciTech Connect

    Zhang, Pengfei; Li, Mingtao; Jiang, Xueguang; Fang, Youxing; Veith, Gabriel M.; Sun, Xiao-Guang; Dai, Sheng

    2015-11-02

    Polymerized ionic networks (PINs) with six ion pairs per repeating unit are synthesized by nucleophilic-substitution-mediated polymerization or radical polymerization of monomers bearing six 1-vinylimidazolium cations. PIN-based solid-like electrolytes show good ionic conductivities (up to 5.32 × 10-3 S cm-1 at 22 °C), wide electrochemical stability windows (up to 5.6 V), and good interfacial compatibility with the electrodes.

  18. Ion transport and softening in a polymerized ionic liquid

    DOE PAGES

    Kumar, Rajeev; Bocharova, Vera; Strelcov, Evgheni; Tselev, Alexander; Kravchenko, Ivan I.; Berdzinski, Stefan; Strehmel, Veronika; Ovchinnikova, Olga S.; Minutolo, Joseph A.; Sangoro, Joshua R.; et al

    2014-11-13

    Polymerized ionic liquids (PolyILs) are promising materials for various solid state electronic applications such as dye-sensitized solar cells, lithium batteries, actuators, field-effect transistors, light emitting electrochemical cells, and electrochromic devices. However, fundamental understanding of interconnection between ionic transport and mechanical properties in PolyILs is far from complete. In this paper, local charge transport and structural changes in films of a PolyIL are studied using an integrated experiment-theory based approach. Experimental data for the kinetics of charging and steady state current–voltage relations can be explained by taking into account the dissociation of ions under an applied electric field (known as themore » Wien effect). Onsager's theory of the Wien effect coupled with the Poisson–Nernst–Planck formalism for the charge transport is found to be in excellent agreement with the experimental results. The agreement between the theory and experiments allows us to predict structural properties of the PolyIL films. We have observed significant softening of the PolyIL films beyond certain threshold voltages and formation of holes under a scanning probe microscopy (SPM) tip, through which an electric field was applied. Finally, the observed softening is explained by the theory of depression in glass transition temperature resulting from enhanced dissociation of ions with an increase in applied electric field.« less

  19. Ion transport and softening in a polymerized ionic liquid

    SciTech Connect

    Kumar, Rajeev; Bocharova, Vera; Strelcov, Evgheni; Tselev, Alexander; Kravchenko, Ivan I.; Berdzinski, Stefan; Strehmel, Veronika; Ovchinnikova, Olga S.; Minutolo, Joseph A.; Sangoro, Joshua R.; Agapov, Alexander L.; Sokolov, Alexei P.; Kalinin, Sergei V.; Sumpter, Bobby G.

    2014-11-13

    Polymerized ionic liquids (PolyILs) are promising materials for various solid state electronic applications such as dye-sensitized solar cells, lithium batteries, actuators, field-effect transistors, light emitting electrochemical cells, and electrochromic devices. However, fundamental understanding of interconnection between ionic transport and mechanical properties in PolyILs is far from complete. In this paper, local charge transport and structural changes in films of a PolyIL are studied using an integrated experiment-theory based approach. Experimental data for the kinetics of charging and steady state current–voltage relations can be explained by taking into account the dissociation of ions under an applied electric field (known as the Wien effect). Onsager's theory of the Wien effect coupled with the Poisson–Nernst–Planck formalism for the charge transport is found to be in excellent agreement with the experimental results. The agreement between the theory and experiments allows us to predict structural properties of the PolyIL films. We have observed significant softening of the PolyIL films beyond certain threshold voltages and formation of holes under a scanning probe microscopy (SPM) tip, through which an electric field was applied. Finally, the observed softening is explained by the theory of depression in glass transition temperature resulting from enhanced dissociation of ions with an increase in applied electric field.

  20. Ion transport and softening in a polymerized ionic liquid

    NASA Astrophysics Data System (ADS)

    Kumar, Rajeev; Bocharova, Vera; Strelcov, Evgheni; Tselev, Alexander; Kravchenko, Ivan I.; Berdzinski, Stefan; Strehmel, Veronika; Ovchinnikova, Olga S.; Minutolo, Joseph A.; Sangoro, Joshua R.; Agapov, Alexander L.; Sokolov, Alexei P.; Kalinin, Sergei V.; Sumpter, Bobby G.

    2014-12-01

    Polymerized ionic liquids (PolyILs) are promising materials for various solid state electronic applications such as dye-sensitized solar cells, lithium batteries, actuators, field-effect transistors, light emitting electrochemical cells, and electrochromic devices. However, fundamental understanding of interconnection between ionic transport and mechanical properties in PolyILs is far from complete. In this work, local charge transport and structural changes in films of a PolyIL are studied using an integrated experiment-theory based approach. Experimental data for the kinetics of charging and steady state current-voltage relations can be explained by taking into account the dissociation of ions under an applied electric field (known as the Wien effect). Onsager's theory of the Wien effect coupled with the Poisson-Nernst-Planck formalism for the charge transport is found to be in excellent agreement with the experimental results. The agreement between the theory and experiments allows us to predict structural properties of the PolyIL films. We have observed significant softening of the PolyIL films beyond certain threshold voltages and formation of holes under a scanning probe microscopy (SPM) tip, through which an electric field was applied. The observed softening is explained by the theory of depression in glass transition temperature resulting from enhanced dissociation of ions with an increase in applied electric field.Polymerized ionic liquids (PolyILs) are promising materials for various solid state electronic applications such as dye-sensitized solar cells, lithium batteries, actuators, field-effect transistors, light emitting electrochemical cells, and electrochromic devices. However, fundamental understanding of interconnection between ionic transport and mechanical properties in PolyILs is far from complete. In this work, local charge transport and structural changes in films of a PolyIL are studied using an integrated experiment-theory based approach

  1. High-flux ionic diodes, ionic transistors and ionic amplifiers based on external ion concentration polarization by an ion exchange membrane: a new scalable ionic circuit platform.

    PubMed

    Sun, Gongchen; Senapati, Satyajyoti; Chang, Hsueh-Chia

    2016-04-01

    A microfluidic ion exchange membrane hybrid chip is fabricated using polymer-based, lithography-free methods to achieve ionic diode, transistor and amplifier functionalities with the same four-terminal design. The high ionic flux (>100 μA) feature of the chip can enable a scalable integrated ionic circuit platform for micro-total-analytical systems.

  2. High-flux ionic diodes, ionic transistors and ionic amplifiers based on external ion concentration polarization by an ion exchange membrane: a new scalable ionic circuit platform.

    PubMed

    Sun, Gongchen; Senapati, Satyajyoti; Chang, Hsueh-Chia

    2016-04-01

    A microfluidic ion exchange membrane hybrid chip is fabricated using polymer-based, lithography-free methods to achieve ionic diode, transistor and amplifier functionalities with the same four-terminal design. The high ionic flux (>100 μA) feature of the chip can enable a scalable integrated ionic circuit platform for micro-total-analytical systems. PMID:26960551

  3. Gated Seebeck Using Polymerized Ionic Liquid Gate Dielectrics

    NASA Astrophysics Data System (ADS)

    Thomas, Elayne; Popere, Bhooshan; Fang, Haiyu; Chabinyc, Michael; Segalman, Rachel

    Thermoelectric materials have the ability to convert a temperature gradient into usable electrical power via the Seebeck effect. This phenomenon is directly related to the material's Seebeck coefficient and electrical conductivity, which are in turn linked to its electron (or hole) mobility and carrier concentration. Organic semiconductors show promise for thermoelectric applications due to their flexibility and low-temperature manufacturing techniques; however, the role of ionized dopants on charge transport in these materials remains poorly understood. In this work, we use polymerized ionic liquids (PILs) as a gate dielectric in organic field-effect transistors to directly control the concentration of charges in the conducting channel. We report a method to tune the carrier concentration in the transistor channel via electrostatic gate modulation. We observe carrier concentration levels that are comparable to traditional doping methods with the added ability to precisely tune the concentration of charges induced. With this process, we aim to gather new information on the effect of ions on the performance of organic semiconductors in hopes of better understanding charge transport in conducting polymers on a molecular level.

  4. Novel double-confined polymeric ionic liquids as sorbents for solid-phase microextraction with enhanced stability and durability in high-ionic-strength solution.

    PubMed

    Feng, Juanjuan; Sun, Min; Xu, Lili; Wang, Shuai; Liu, Xia; Jiang, Shengxiang

    2012-12-14

    Because of the occurrence of ion exchange between high-ionic-strength solution and anions of polymeric ionic liquids (PILs), PILs based solid-phase microextraction (SPME) fibers were rarely used in direct immersion mode to high-salt-added samples. In this work, a novel double-confined PIL sorbent was prepared by co-polymerization of cation and anion of 1-vinyl-3-octylimidzaolium p-styrenesulfonate (VOIm(+)SS(-)). The poly(VOIm(+)-SS(-)) was chemically bonded onto functionalized stainless steel wire via surface radical chain-transfer reaction. Stability of poly(VOIm(+)-SS(-)) in high-ionic-strength solution was investigated and compared with that of poly(1-vinyl-3-octylimidzaolium benzenesulfonate) (poly(VOIm(+)BS(-))) by elemental analysis of sulfur element, and results turned out that the poly(VOIm(+)-SS(-)) was more stable. Coupled to gas chromatography (GC), the poly(VOIm(+)-SS(-)) fiber was used to extract three sorts of compounds including anilines, phenols and phthalate esters in aqueous solution. The as-established method showed good linearity, low detection limits, and acceptable repeatability. The direct immersion SPME-GC method was applied to determine the model phthalate esters in bottled mineral water. The determination results were satisfactory.

  5. Ionic-polymeric models and the amphoteric behavior of water in silicate melts

    NASA Astrophysics Data System (ADS)

    Moretti, R.

    2012-04-01

    In silicate melts it is almost impossible to readily distinguish solute and solvent like in aqueous solutions. The anionic framework of silicate melts, in fact, makes solute and solvents so intimately related that one cannot identify a solvation shell and identify directly, from structural studies, the complexes needed to define acid-base reactions. Therefore, the distinction between solute and solvent becomes blurred in systems such as silicate melts, because speciation is not only complex but changes with the marked depolymerization of the silicate framework that obtains from pure SiO2 to metal-oxide rich compositions. These features do not allow proper understanding of the actual physico-chemical role of many species detected by conventional techniques, a fact which can lead to confusing notation. However, these may not be serious limits to account correctly for the acid-base reactions that take place in every kind of magmatic setting, provided a 'syntax' describing the effective interactions among significative cationic and anionic entities. In particular, the syntax for acid-base exchanges is needed such that constituting oxides (i.e. chemical components) can be treated independently of (but not necessarily extraneous to) structural features in defining such entities. So-called ionic-polymeric models highlight the mutual correspondence between polymerization and acid-base properties of dissolved oxides through the Lux-Flood formalism for molten oxides. They thus provide the syntax to write chemical exchanges, but have no pretension to structural description. In fact the concept of melt polymerization is used to identify basic anions and cations that can be used, along with their formal charge, to describe effectively acid-base interactions taking place in melts. In this respect, an example is given by the description of the amphoteric behavior of water dissolved on melts, hence water autoprotolysis. Although it exerts a profound influence on properties of

  6. Release of Small Polyuronides from Nitella Cell Walls during Ionic Exchange

    PubMed Central

    Gillet, Claude; Cambier, Pierre; Liners, Françoise

    1992-01-01

    Mono-divalent ion exchange in isolated cell walls of Nitella flexilis (L.) Ag. induces a marked loss of wall polymers and a decrease in the wall cationic exchange capacity. These data correlate with the replacement in the walls of adsorbed Mn2+ by Na+ ions. Boiling wall samples in methanol for 1 h or keeping the ionic solutions chilled to 4°C does not inhibit the cell wall polymer leakage but modifies the kinetics both of the ionic exchange and of the released polymers. These data are more compatible with physical rather than enzymic induced processes. The extracted polymers in the successively renewed NaCl solutions initially belong to the wall protein and pectin fractions and mainly to pectic fractions subsequently. Determination of the average degree of polymerization shows that the average molecular size of the lost acidic polysaccharides increases with extraction time up an average polymerization degree of 25. Enzyme-linked immunosorbent assay inhibition tests show the presence of homopolymer blocks equal to or higher than 10 in the released polymer fragments. Compositional analysis of released polysaccharides suggests that the pectin lost by action of monovalent ions was largely composed of rhamnogalacturonans whose acidic residue fraction is approximately 60% in association with galactose chains. Small quantities of glucuronylated xylans are also found. PMID:16653066

  7. Polymeric nanocomposite proton exchange membranes prepared by radiation-induced polymerization for direct methanol fuel cell

    NASA Astrophysics Data System (ADS)

    Kim, Young-Seok; Seo, Kwang-Seok; Choi, Seong-Ho

    2016-01-01

    The vinyl group-modified montmorillonite clay (F-MMT), vinyl group-modified graphene oxide (F-GO), and vinyl group-modified multi-walled carbon nanotube (F-MWNT) were first prepared by ion exchange reaction of 1-[(4-ethylphenyl)methyl]-3-butyl-imidazolium chloride in order to use the materials for protection against methanol cross-over in direct methanol fuel cell (DMFC) membrane. Then polymeric nanocomposite membranes with F-MMT, F-GO, and F-MWNT were prepared by the solvent casting method after radiation-induced polymerization of vinyl monomers in water-methanol mixture solvents. The proton conductivity, water uptake, ion-exchange capacity, methanol permeability, and DMFC performance of the polymeric nanocomposite membranes with F-MMT, F-GO, and F-MWNT were evaluated.

  8. MINOR ACTINIDE SEPARATIONS USING ION EXCHANGERS OR IONIC LIQUIDS

    SciTech Connect

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

    2011-09-20

    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.

  9. Thiophene-based ionic liquids: synthesis, physical properties, self-assembly and oxidative polymerization.

    SciTech Connect

    Burns, C. T.; Lee, S.; Seifert, S.; Firestone, M. A.

    2008-07-01

    Preparation and polymerization of methylimidazolium-based ionic liquids (ILs) that incorporate a thiophene moiety at the terminus of a C{sub 10} alkyl chain are described. Both a bromide and nitrate salt of the amphiphilic thiophene IL self-assembles in water (albeit the nitrate to a lesser extent), adopting columnar mesophases. Polarized optical microscopy and small-angle X-ray scattering (SAXS) studies show that at low water content the IL-water binary mixtures form liquid crystalline mesophases possessing significant short-range ordering due to strong {pi} interactions between adjacent thiophene moieties. At higher water content, the short-range ordering is lost, but long-range ordering persists up to ca. 45% (w/w) water. The chemical oxidative coupling of the nitrate monomer yields a highly water-soluble polymer. Electrochemical studies show that the polymer possesses a high oxidation potential (1.95 V) and thus, is resistant to chemical doping. In dilute aqueous solution, electronic absorption spectroscopy and X-ray scattering show the polymer adopts a random, coil-like conformational state. Slight improvement in the polymer conformation can be achieved by exchange of the counter anion.

  10. On the mechanism of radiation-induced polymerization of vinyl monomers in ionic liquid

    NASA Astrophysics Data System (ADS)

    Liu, Yaodong; Wu, Guozhong

    2005-06-01

    An attempt was made to investigate the mechanism controlling the radiation-induced polymerization of vinyl monomers in room temperature ionic liquids. For that purpose, copolymerization of styrene (St) and methyl methacrylate (MMA) was initiated by 60Co gamma radiation in a moisture-stable ionic liquid, [choline chloride][ZnCl 2], and its mixture with THF (4:1 v/v). By analyzing the product composition with FTIR for a series of poly(St-co-MMA) samples, it was found that the mole fraction of St in the copolymer is linearly proportional to the mole fraction of St in the feed. Therefore, radiation polymerization in ionic liquid and its mixture with organic solvent is suggested to be a radical propagating process.

  11. The effects of non-ionic polymeric surfactants on the cleaning of biofouled hydrogel materials.

    PubMed

    Guan, Allan; Li, Zhenyu; Phillips, K Scott

    2015-01-01

    Block co-polymer surfactants have been used for cleaning hydrogel medical devices that contact the body (e.g., contact lenses) because of their biocompatibility. This work examined the relationship between concentration and detergency of two non-ionic polymeric surfactants (Pluronic F127 and Triton X-100) for cleaning protein soil, with anionic surfactants (sodium dodecyl sulfate and sodium laureth sulfate) as positive controls. Surface plasmon resonance was used to quantify removal of simulated tear soil from self-assembled monolayer surfaces, and a microplate format was used to study the removal of fluorescently labeled soil proteins from contact lenses. While detergency increased as a function of concentration for anionic surfactants, it decreased with concentration for the two polymeric surfactants. The fact that the protein detergency of some non-ionic polymeric surfactants did not increase with concentration above the critical micelle concentration could have implications for optimizing the tradeoff between detergency and biocompatibility. PMID:26469384

  12. The design of polymeric ionic liquids for the preparation of functional materials.

    SciTech Connect

    Green, O.; Grubjesic, S.; Lee, S.; Firestone, M. A.; Materials Science Division

    2009-01-01

    The tunability of the chemical composition of ionic liquids (ILs), achieved by pairing various organic cations with numerous anions, allows for fine control of their physicochemical properties and has been widely used for the adjustment of the IL solvent characteristics. Exploitation of IL structural modularity coupled with chemical modification of the cation or anion to incorporate polymerizable groups is now an active area of research, resulting in the development of polymeric ionic liquids (poly(IL)s). The emergence of poly(IL)s as functional materials in the areas of polymer electrolytes, sorbents, dispersing agents, and nanomaterials is reviewed.

  13. Polymer-supported ionic-liquid-like phases (SILLPs): transferring ionic liquid properties to polymeric matrices.

    PubMed

    Sans, Victor; Karbass, Naima; Burguete, M Isabel; Compañ, Vicente; García-Verdugo, Eduardo; Luis, Santiago V; Pawlak, Milena

    2011-02-01

    The physico-chemical properties of polymers with ionic-liquid-like moieties covalently bound to their surfaces (SILLPs) have been studied by thermal and spectroscopic techniques, as well as by direct impedance and dielectric measurements, and compared to those of the corresponding bulk ionic liquids. The effective transfer of properties from ionic liquids in solution to the supported species has thereby been demonstrated. The effects of the chemical nature of these tunable "solid solvents" on their macroscopic swelling and microwave heating, as well as the stabilities and activities of different catalytic moieties immobilized on the SILLPs, have been studied. Finally, the experimental effect observed in microwave heating can be directly correlated with the values of tan δ derived from dielectric measurements.

  14. Effect of Molecular Weight on the Ion Transport Mechanism in Polymerized Ionic Liquids

    DOE PAGES

    Fan, Fei; Wang, Weiyu; Holt, Adam P.; Feng, Hongbo; Uhrig, David; Lu, Xinyi; Hong, Tao; Wang, Yangyang; Kang, Nam-Goo; Mays, Jimmy; et al

    2016-06-07

    The unique properties of ionic liquids (ILs) have made them promising candidates for electrochemical applications. Polymerization of the corresponding ILs results in a new class of materials called polymerized ionic liquids (PolyILs). Though PolyILs offer the possibility to combine the high conductivity of ILs and the high mechanical strength of polymers, their conductivities are typically much lower than that of the corresponding small molecule ILs. In this study, seven PolyILs were synthesized having degrees of polymerization ranging from 1 to 333, corresponding to molecular weights (MW) from 482 to 160 400 g/mol. Depolarized dynamic light scattering, broadband dielectric spectroscopy, rheology,more » and differential scanning calorimetry were employed to systematically study the influence of MW on the mechanism of ionic transport and segmental dynamics in these materials. Finally, the modified Walden plot analysis reveals that the ion conductivity transforms from being closely coupled with structural relaxation to being strongly decoupled from it as MW increases.« less

  15. Effect of water uptake on morphology of polymerized ionic liquid block copolymers and random copolymers

    NASA Astrophysics Data System (ADS)

    Wang, Tsen-Shan; Ye, Yuesheng; Elabd, Yossef; Winey, Karen

    2012-02-01

    Dynamic studies of polymer morphology probe how the physical properties of polymerized ionic liquids are affected by the environment, such as temperature or moisture. For a series of poly(methyl methacrylate-b-1-[2-(methacryloyloxy)ethyl]-3-Butylimidazolium X^-) block and random copolymers with hydrophilic counterions (X^- = Br^-, HCO3^-, OH^-), the introduction of water vapor to the system can swell the ionic liquid block, causing enlarged hydrophilic domains and swollen channels for ion conduction. This expected expansion of ionic liquid domains in humid environments can be used to intelligently design these copolymers for use in technological applications. The effect of water vapor exposure in these imidazolium-based acrylate polymers is studied by small-angle X-ray scattering. These morphology results will be discussed alongside complementary studies of water uptake and ion conductivity.

  16. Free radical (co)polymerization of methyl methacrylate and styrene in room temperature ionic liquids

    NASA Astrophysics Data System (ADS)

    Zhang, Hongwei

    Conventional free radical polymerizations were carried out in a variety of room temperature ionic liquids (RTILs). Generally, methyl methacrylate (MMA) and styrene (St) were used as typical monomers to compare the polymerization behavior both in RTILs and in common volatile organic compound solvents (VOCs). In most cases, it was observed that both yields and molecular weights are enhanced in the RTIL. While we believe the "diffusion-controlled termination" mechanism makes the termination of the radical propagating chains difficult due to the highly viscous nature of RTIL, other researchers have suggested that the rapid polymerization rates are due to the high polarity of these reaction media. By employing more than a dozen RTILs with a wide range of anions and cations, we attempted to correlate the viscosity and polarity of the RTILs with the molecular weights and polymerization rates. This correlation was not successful, suggesting that other parameters may also play a role in affecting the polymerization behavior. Other kinds of polymerizations have also been attempted including nitroxide-mediated living radical polymerizations of St and MMA in 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6), and redox initiation system initiated polymerization of MMA through redox pair formed by cation of trihexyl-tetradecyl-phosphonium bis(2,4,4-trimethylpentyl) phosphinate ([H3TDP] [(PM3) 2P]) and BPO. The formation of PSt-b-PMMA by sequential monomer addition through the standard free radical polymerization mechanism, using BPO as initiator, can be realized in [BMIM]PF6 due to the insolubility of polymerized first block---PSt in [BMIM]PF6. The macroradicals wrapped inside the chain coils have prolonged lifetimes because of the diminished termination, which allow some of these radicals to initiate polymerization of MMA at room temperature to form diblock copolymer. Solvents effects on reactivity ratios for free radical statistical copolymerization have been

  17. A novel aromatically functional polymeric ionic liquid as sorbent material for solid-phase microextraction.

    PubMed

    Feng, Juanjuan; Sun, Min; Li, Jubai; Liu, Xia; Jiang, Shengxiang

    2012-03-01

    Physical and chemical properties of ionic liquids (ILs) are significantly affected by types of their cations and anions. In this paper, a novel aromatically functional 1-vinyl-3-octylimidazolium 2-naphthalene-sulfonate salt was synthesized through metathesis reaction between 1-vinyl-3-octylimidazolium bromide and sodium 2-naphthalene-sulfonate, and polymerized onto the stainless steel wire in situ via surface radical chain-transfer reaction. Octanol/water distribution coefficient of the ionic liquid was studied and compared with that of 1-vinyl-3-octylimidazolium hexafluorophosphate. Partition coefficients of polycyclic aromatic hydrocarbons (PAHs) on these two polymeric ionic liquids-coated fibers indicated the enhanced hydrophobicity and aromaticity of the target IL. Analytical parameters exhibited high extraction efficiency of the novel fiber. Calibration ranges for several PAHs were from 0.02 to 200 μg L⁻¹. Limits of detection (LODs) were ranged from 0.005 to 0.01 μg L⁻¹. Application reliability of the proposed fiber was also investigated with some phthalate ester plasticizers. LODs were ranged from 0.02 to 0.05 μg L⁻¹. Hair spray and nail polish were used as real samples, and di-n-butyl phthalate and di-(2-ethyl-hexyl) phthalate were quantified with the established method. PMID:22265783

  18. Ionic Liquids and New Proton Exchange Membranes for Fuel Cells

    NASA Technical Reports Server (NTRS)

    Belieres, Jean-Philippe

    2004-01-01

    There is currently a great surge of activity in fuel cell research as laboratories across the world seek to take advantage of the high energy capacity provided by &el cells relative to those of other portable electrochemical power systems. Much of this activity is aimed at high temperature fie1 cells, and a vital component of such &el cells must be the availability of a high temperature stable proton-permeable membrane. NASA Glenn Research Center is greatly involved in developing this technology. Other approaches to the high temperature fuel cell involve the use of single- component or almost-single-component electrolytes that provide a path for protons through the cell. A heavily researched case is the phosphoric acid fuel cell, in which the electrolyte is almost pure phosphoric acid and the cathode reaction produces water directly. The phosphoric acid fie1 cell delivers an open circuit voltage of 0.9 V falling to about 0.7 V under operating conditions at 170 C. The proton transport mechanism is mainly vehicular in character according to the viscosity/conductance relation. Here we describe some Proton Transfer Ionic Liquids (PTILs) with low vapor pressure and high temperature stability that have conductivities of unprecedented magnitude for non-aqueous systems. The first requirement of an ionic liquid is that, contrary to experience with most liquids consisting of ions, it must have a melting point that is not much above room temperature. The limit commonly suggested is 100 C. PTILs constitute an interesting class of non-corrosive proton-exchange electrolyte, which can serve well in high temperature (T = 100 - 250 C) fuel cell applications. We will present cell performance data showing that the open circuit voltage output, and the performance of a simple H2(g)Pt/PTIL/Pt/O2(g) fuel cell may be superior to those of the equivalent phosphoric acid electrolyte fuel cell both at ambient temperature and temperatures up to and above 200 C. My work at NASA Glenn Research

  19. Optimizing the electrochemical performance of imidazolium-based polymeric ionic liquids by varying tethering groups

    NASA Astrophysics Data System (ADS)

    Jia, Zhe

    Increasing efforts have been made in the area of sustainable alternative energy devices in the past few decades in order to develop high efficiency, low-cost electrochemical devices with sufficient long-term stability. Due to the drawbacks of conventional organic liquid electrolytes, such as leakage, volatility, flammability, and toxicity, the synthesis of solvent-free electrolyte materials has been studied world-wide. Among all the alternatives, polymer electrolytes are of great interest and have attracted many research groups. Solid-state polymer electrolytes and in particular, polymer ionic liquids (PILs), considered to be promising candidates, have been under studied widely. Ionic Liquids (ILs), defined as organic/inorganic salts with m.p. lower than 100 °C, offer good chemical stability, low flammability, negligible vapor pressure and high ionic conductivity. PILs, as the polymerized state of ILs, not only present some of the unique properties of ILs, but also benefit from the intrinsic properties of polymers, such as better thermal and chemical stability, enhanced mechanical properties, and tunable solution properties. The constrained structure of PILs may help to overcome fabrication and leakage problems associated with simple liquid electrolytes, but typically also leads to lower ionic conductivity. Once polymerized, the ionic conductivity of PILs drops substantially, usually by several orders of magnitude compared to the corresponding monomers. Therefore, to improve PILs chain mobilitiy is crucial. Previous studies suggest that a flexible tethering group should make the polymer backbone less rigid and increase electrolyte ion mobility. To investigate how tethering groups affect both electrochemical performance and physical properties of free ILs and PILs, we first report the synthesis and characterization of a novel class of imidazolium (Im) based IL model compounds and their corresponding PILs. Poly(ethylene oxide)s (PEOs), considered to be promising

  20. Trading polymeric microspheres: exchanging DNA molecules via microsphere interaction.

    PubMed

    Morimoto, Nobuyuki; Muramatsu, Kanna; Nomura, Shin-ichiro M; Suzuki, Makoto

    2015-04-01

    A new class of artificial molecular transport system is constructed by polymeric microspheres. The microspheres are prepared by self-assembly of poly(ethylene glycol)-block-poly(3-dimethyl(methacryloyloxyethyl)ammonium propane sulfonate), PEG-b-PDMAPS, by intermolecular dipole-dipole interaction of sulfobetaine side chains in water. Below the upper critical solution temperature (UCST) of PEG-b-PDMAPS, the microspheres (∼1μm) interact with other microspheres by partial and transit fusion. In order to apply the interaction between microspheres, a 3'-TAMRA-labeled single-stranded DNA oligomer (ssDNA) is encapsulated into a PEG-b-PDMAPS microsphere by thermal treatment. The exchange of ssDNA between microspheres is confirmed by fluorescence resonance energy transfer (FRET) quenching derived from double-stranded formation with complementary 5'-BHQ-2-labeled ssDNA encapsulated in PEG-b-PDMAPS microspheres. The exchange rate of ssDNA is controllable by tuning the composition of the polymer. The contact-dependent transport of molecules can be applied in the areas of microreactors, sensor devices, etc. PMID:25731098

  1. Trading polymeric microspheres: exchanging DNA molecules via microsphere interaction.

    PubMed

    Morimoto, Nobuyuki; Muramatsu, Kanna; Nomura, Shin-ichiro M; Suzuki, Makoto

    2015-04-01

    A new class of artificial molecular transport system is constructed by polymeric microspheres. The microspheres are prepared by self-assembly of poly(ethylene glycol)-block-poly(3-dimethyl(methacryloyloxyethyl)ammonium propane sulfonate), PEG-b-PDMAPS, by intermolecular dipole-dipole interaction of sulfobetaine side chains in water. Below the upper critical solution temperature (UCST) of PEG-b-PDMAPS, the microspheres (∼1μm) interact with other microspheres by partial and transit fusion. In order to apply the interaction between microspheres, a 3'-TAMRA-labeled single-stranded DNA oligomer (ssDNA) is encapsulated into a PEG-b-PDMAPS microsphere by thermal treatment. The exchange of ssDNA between microspheres is confirmed by fluorescence resonance energy transfer (FRET) quenching derived from double-stranded formation with complementary 5'-BHQ-2-labeled ssDNA encapsulated in PEG-b-PDMAPS microspheres. The exchange rate of ssDNA is controllable by tuning the composition of the polymer. The contact-dependent transport of molecules can be applied in the areas of microreactors, sensor devices, etc.

  2. Conductivity Scaling Relationships in Nanostructured Membranes based on Protic Polymerized Ionic Liquids

    NASA Astrophysics Data System (ADS)

    Sanoja, Gabriel; Lynd, Nathaniel; Segalman, Rachel

    2015-03-01

    Nanostructured membranes based on protic polymerized ionic liquids are of great interest for a variety of electrochemical applications. Understanding the relationship between composition, structure, and ionic conductivity for these materials is essential for designing novel membranes with improved properties. In this work, we explore the effect of volume fraction of ionic liquid on conductivity, σ using a model system composed of poly[isoprene-block-(ethylene oxide-stat-histamine glycidyl ether) diblock copolymers [PI- b - P(EO-stat-HGE)] and the resulting [PI- b - P(EO-stat-IL)] obtained after treatment with trifluoroacetic acid. These materials self-assemble into lamellar structures with volume fractions of ionic liquid ranging from 0.50 to 0.90 as demonstrated by SAXS. PI- b - P(EO-stat-IL) membranes exhibit conductivities up to 4 x 10-3 S/cm at room temperature. In addition, PI- b - P(EO-stat-IL) based membranes have lower water uptake (λ = 8-10) in comparison with most proton conducting membranes reported elsewhere. The low λ in these membranes might translate into a stronger effect of morphology on transport properties. Joint Center for Artificial Photosynthesis.

  3. Fabrication of core-shell structured magnetic nanocellulose base polymeric ionic liquid for effective biosorption of Congo red dye.

    PubMed

    Beyki, Mostafa Hossein; Bayat, Mehrnoosh; Shemirani, Farzaneh

    2016-10-01

    Ionic liquids are considered to be a class of environmentally friendly compounds as combination of them with bioresource polymeric substances such as; cellulose, constitute emerging coating materials. Biosorption by polymeric ionic liquids exhibits an attractive green way that involves low cost and irrespective of toxicity. As a result, a novel polymeric ionic liquid has been developed by the reaction of one step synthesized Fe3O4-cellulose nanohybrid, epichlorohydrin and 1-methylimidazole and employed as a green sorbent for efficient biosorption of Congo red dye. Effective parameters on dye removing as well as their interactions were determined with response surface methodology (RSM). Congo red adsorption showed fast equilibrium time (11min) with maximum uptake of 131mgg(-1). Isotherm study revealed that Langmuir adsorption model can better describe dye adsorption behavior. Regeneration of the sorbent was performed with a mixture of methanol-acetone-NaOH (3.0molL(-1)) solution. PMID:27372013

  4. Innovative Poly(Ionic Liquid)s by the Polymerization of Deep Eutectic Monomers.

    PubMed

    Isik, Mehmet; Ruiperez, Fernando; Sardon, Haritz; Gonzalez, Alba; Zulfiqar, Sonia; Mecerreyes, David

    2016-07-01

    The incorporation of ionic liquid (IL) chemistry into functional polymers has extended the properties and applications of polyelectrolytes. However, ILs are expensive due to the presence of fluorinated anions or complicated synthetic steps which limit their technological viability. Here, we show a new family of poly(ionic liquid)s (PILs) which are based in cheap and renewable chemicals and involves facile synthetic approaches. Thus, deep eutectic monomers (DEMs) are prepared for the first time by using quaternary ammonium compounds and various hydrogen bond donors such as citric acid, terephthalic acid or an amidoxime. The deep eutectic formation is made through a simple mixing of the ingredients. Differential scanning calorimetry, nuclear magnetic resonance (NMR) and computational studies reveal the formation of the DEMs due to the ionic interactions. The resulting DEMs are liquid which facilitates their polymerization using mild photopolymerization or polycondensation strategies. Spectroscopic characterizations reveal the successful formation of the polymers. By this way, a new family of PILs can be synthesized which can be used for different applications. As an example, the polymers show promising performance as solid CO2 sorbents. Altogether the deep eutectic monomer route can lead to non-toxic, cheap and easy-to-prepare alternatives to current PILs for different applications.

  5. Immobilizing Cr3+ with SO3H-functionalized solid polymeric ionic liquids as efficient and reusable catalysts for selective transformation of carbohydrates into 5-hydroxymethylfurfural.

    PubMed

    Li, Hu; Zhang, Qiuyun; Liu, Xiaofang; Chang, Fei; Zhang, Yuping; Xue, Wei; Yang, Song

    2013-09-01

    A series of functional polymeric ionic liquids (FPILs) were prepared by coupling of SO3H-functionalized polymeric ionic liquids with different counterpart anions containing or excluding CrCl3·6H2O, and characterized by SEM, FT-IR, XRD, NH3-TPD, TG, melting point, ICP-AES, and TEM. The catalytic activity of the prepared solid FPILs was investigated for the conversion of biomass including fructose, glucose and cellulose into 5-hydroxymethylfurfural (HMF) with the presence of DMSO-mediated solvents, successively producing moderate to excellent yields of HMF under atmospheric pressure. The FPILs catalysts developed in this study present improved performance on fructose-to-HMF conversion over other solid catalysts, such as functional ionic liquids supported by silica, metal oxides and strong acid ion exchange resin catalysts, and can be very easily recycled at least five times without significant loss of activity. In addition, a kinetic analysis was carried out to illustrate the formation of HMF. PMID:23850822

  6. Ionic liquid based polymeric liposomes: A stable and biocompatible soft platform for bioelectrochemistry.

    PubMed

    Tian, Yanping; Xia, Jiarui; Zhang, Ling; Zhang, Junhui; Jiang, Yi; Zhang, Yao; Yang, Lini; Zhang, Qian; Xia, Lixin

    2016-10-01

    Polymeric liposomes (denoted as ILs-polysomes) are a biocompatible and conductive nanomaterial, which was first utilised as the electrode material for immobilising and biosensing redox enzyme horseradish peroxide (HRP). The morphology and surface property of IL-polysomes was characterised and systematically compared with unpolymerised ionic liquid based liposomes (denoted as ILs-liposomes). Differing from IL-liposomes, IL-polysomes preserves their original morphology and bilayer membrane structure on glassy carbon (GC) electrodes due to the cross-linking of polymerised lipids, thus exhibiting excellent stability and specific biocompability. Because of the existence of imidazolium ionic liquid moieties on the outer surface, IL-polysomes displays a positive charge in aqueous solution, leading to oppositely charged HRP self-assembling onto the vesicles to form HRP/IL-polysomes/PVA/GC electrodes. Owing to the combined merits of ILs and liposomes, electron transfer between HRP-Fe(III)/Fe(II) redox couples of immobilised enzymes and GC electrodes can be achieved. Therefore, HRP/IL-polysomes/PVA/GC electrodes exhibited good electrocatalytic performance toward the electrocatalysis of H2O2. Accordingly, IL-polysomes could act as an efficient charged platform for the self-assembled redox enzymes to realise direct electrochemistry. IL-polysomes have a promising application in the fabrication of third-generation electrochemical biosensors.

  7. Theoretical studies on CO2 capture behavior of quaternary ammonium-based polymeric ionic liquids.

    PubMed

    Wang, Tao; Ge, Kun; Chen, Kexian; Hou, Chenglong; Fang, Mengxiang

    2016-05-14

    Quaternary ammonium-based polymeric ionic liquids (PILs) are novel CO2 sorbents as they have high capacity, high stability and high binding energy. Moreover, the binding energy of ionic pairs to CO2 is tunable by changing the hydration state so that the sorbent can be regenerated through humidity adjustment. In this study, theoretical calculations were conducted to reveal the mechanism of the humidity swing CO2 adsorption, based on model compounds of quaternary ammonium cation and carbonate anions. The electrostatic potential map demonstrates the anion, rather than the cation, is chemically preferential for CO2 adsorption. Further, the proton transfer process from water to carbonate at the sorbent interface is successfully depicted with an intermediate which has a higher energy state. By determining the CO2 adsorption energy and activation energy at different hydration states, it is discovered that water could promote CO2 adsorption by reducing the energy barrier of proton transfer. The adsorption/desorption equilibrium would shift to desorption by adding water, which constitutes the theoretical basis for humidity swing. By analyzing the hydrogen bonding and structure of the water molecules, it is interesting to find that the CO2 adsorption weakens the hydrophilicity of the sorbent and results in release of water. The requirement of latent heat for the phase change of water could significantly reduce the heat of adsorption. The special "self-cooling" effect during gas adsorption can lower the temperature of the sorbent and benefit the adsorption isotherms.

  8. Polymeric ionic liquid-plastic crystal composite electrolytes for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Li, Xiaowei; Zhang, Zhengxi; Li, Sijian; Yang, Li; Hirano, Shin-ichi

    2016-03-01

    In this work, composite polymer electrolytes (CPEs), that is, 80%[(1-x)PIL-(x)SN]-20%LiTFSI, are successfully prepared by using a pyrrolidinium-based polymeric ionic liquid (P(DADMA)TFSI) as a polymer host, succinonitrile (SN) as a plastic crystal, and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as a lithium salt. XRD and DSC measurements confirm that the as-obtained CPEs have amorphous structures. The 80%[50%PIL-50%SN]-20%LiTFSI (50% SN) electrolyte reveals a high room temperature ionic conductivity of 5.74 × 10-4 S cm-1, a wide electrochemical window of 5.5 V, as well as good mechanical strength with a Young's modulus of 4.9 MPa. Li/LiFePO4 cells assembled with the 50% SN electrolyte at 0.1C rate can deliver a discharge capacity of about 150 mAh g-1 at 25 °C, with excellent capacity retention. Furthermore, such cells are able to achieve stable discharge capacities of 131.8 and 121.2 mAh g-1 at 0.5C and 1.0C rate, respectively. The impressive findings demonstrate that the electrolyte system prepared in this work has great potential for application in lithium ion batteries.

  9. Crosslinked polymeric ionic liquids as solid-phase microextraction sorbent coatings for high performance liquid chromatography.

    PubMed

    Yu, Honglian; Merib, Josias; Anderson, Jared L

    2016-03-18

    Neat crosslinked polymeric ionic liquid (PIL) sorbent coatings for solid-phase microextraction (SPME) compatible with high-performance liquid chromatography (HPLC) are reported for the first time. Six structurally different PILs were crosslinked to nitinol supports and applied for the determination of select pharmaceutical drugs, phenolics, and insecticides. Sampling conditions including sample solution pH, extraction time, desorption solvent, desorption time, and desorption solvent volume were optimized using design of experiment (DOE). The developed PIL sorbent coatings were stable when performing extractions under acidic pH and remained intact in various organic desorption solvents (i.e., methanol, acetonitrile, acetone). The PIL-based sorbent coating polymerized from the IL monomer 1-vinyl-3-(10-hydroxydecyl) imidazolium chloride [VC10OHIM][Cl] and IL crosslinker 1,12-di(3-vinylbenzylimidazolium) dodecane dichloride [(VBIM)2C12] 2[Cl] exhibited superior extraction performance compared to the other studied PILs. The extraction efficiency of pharmaceutical drugs and phenolics increased when the film thickness of the PIL-based sorbent coating was increased while many insecticides were largely unaffected. Satisfactory analytical performance was obtained with limits of detection (LODs) ranging from 0.2 to 2 μg L(-1) for the target analytes. The accuracy of the analytical method was examined by studying the relative recovery of analytes in real water samples, including tap water and lake water, with recoveries varying from 50.2% to 115.9% and from 48.8% to 116.6%, respectively. PMID:26896916

  10. Conductive polymeric ionic liquids for electroanalysis and solid-phase microextraction.

    PubMed

    Young, Joshua A; Zhang, Cheng; Devasurendra, Amila M; Tillekeratne, L M Viranga; Anderson, Jared L; Kirchhoff, Jon R

    2016-03-01

    Three novel electropolymerizable thiophene-based ionic liquids (ILs) were synthesized and characterized as potential candidates for developing selective extraction media for chemical analysis. Electropolymerization of the bis[(trifluoromethyl)sulfonyl]imide ([NTf2](-)) analogs successfully produced uniform polymeric thin-films on macro- and microelectrode substrates from both vinyl and methylimidazolium IL monomer derivatives. The resultant conducting polymer IL (CPIL) films were characterized by electrochemical methods and found to exhibit attractive behavior towards anionic species while simultaneously providing an exclusion barrier toward cationic species. Thermogravimetric analysis of the thiophene-based IL monomers established a high thermal stability, particularly for the methylimidazolium IL, which was stable until temperatures above 350 °C. Subsequently, the methylimidazolium IL was polymerized on 125 μm platinum wires and utilized for the first time as a sorbent coating for headspace solid-phase microextraction (HS-SPME). The sorbent coating was easily prepared in a reproducible manner, provided high thermal stability, and allowed for the gas chromatographic analysis of polar analytes. The normalized response of the poly[thioph-C6MIm][NTf2]-based sorbent coating exhibited higher extraction efficiency compared to an 85 μm polyacrylate fiber and excellent fiber-to-fiber reproducibility. Therefore, the electropolymerizable thiophene-based ILs were found to be viable new materials for the preparation of sorbent coatings for HS-SPME.

  11. Crosslinked polymeric ionic liquids as solid-phase microextraction sorbent coatings for high performance liquid chromatography.

    PubMed

    Yu, Honglian; Merib, Josias; Anderson, Jared L

    2016-03-18

    Neat crosslinked polymeric ionic liquid (PIL) sorbent coatings for solid-phase microextraction (SPME) compatible with high-performance liquid chromatography (HPLC) are reported for the first time. Six structurally different PILs were crosslinked to nitinol supports and applied for the determination of select pharmaceutical drugs, phenolics, and insecticides. Sampling conditions including sample solution pH, extraction time, desorption solvent, desorption time, and desorption solvent volume were optimized using design of experiment (DOE). The developed PIL sorbent coatings were stable when performing extractions under acidic pH and remained intact in various organic desorption solvents (i.e., methanol, acetonitrile, acetone). The PIL-based sorbent coating polymerized from the IL monomer 1-vinyl-3-(10-hydroxydecyl) imidazolium chloride [VC10OHIM][Cl] and IL crosslinker 1,12-di(3-vinylbenzylimidazolium) dodecane dichloride [(VBIM)2C12] 2[Cl] exhibited superior extraction performance compared to the other studied PILs. The extraction efficiency of pharmaceutical drugs and phenolics increased when the film thickness of the PIL-based sorbent coating was increased while many insecticides were largely unaffected. Satisfactory analytical performance was obtained with limits of detection (LODs) ranging from 0.2 to 2 μg L(-1) for the target analytes. The accuracy of the analytical method was examined by studying the relative recovery of analytes in real water samples, including tap water and lake water, with recoveries varying from 50.2% to 115.9% and from 48.8% to 116.6%, respectively.

  12. Novel self-powered pH indicator using ionic polymeric gel muscles

    NASA Astrophysics Data System (ADS)

    Shahinpoor, Mohsen

    1994-05-01

    A novel design for a torsional spring-loaded pH indicator using ionic polymeric gel fibrous muscles is presented. The essential parts of the proposed self-powered pH indicator are a pair of co-axial and concentric cylinders, an assembly of fibrous polyacrylonitrile (PAN) muscles, a torsional spring, and a dial indicator. The two co-axial cylinders are such that the inner cylinder may pivotally rotate about the central rotation axis that is fixed to the inner bottom or side of the outer cylinder. The outer cylinder also serves as a reservoir for any liquid whose pH is to be determined either statically or dynamically. The internal cylindrical drum is further equipped with a dial indicator on one of its outer end caps such that when a pH environment is present the contraction or expansion of the PAN fibers cause the inner drum to rotate and thus give a reading of the dial indicator. The motion of the dial indicator may also be converted to an electrical signal (voltage) for digital electronics display and computer control. A mathematical model is also presented for the dynamic response of the self-powered pH indicator made with contractile PAN fiber bundle assemblies.

  13. Biocatalytic synthesis of polymeric nanowires by micellar templates of ionic surfactants

    SciTech Connect

    Nazari, K.; Adhami, F.; Najjar-Safari, A.; Salmani, S.; Mahmoudi, A.

    2011-07-15

    Highlights: {yields} Soft-template production of polyguaiacol nanowire was done by peroxidase enzyme. {yields} Main advantage of this simple method is producing soluble encapsulated nanowires. {yields} Nanowire can be easily precipitated and separated by dilution with distilled water. {yields} Size tuned templates of sodium decyl sulfate (d = 2.7 nm) gave nanowires with d = 2-4 nm. {yields} Dried surfactant-coated wires recover freshly on specified and desired applications. -- Abstract: Micelle-templated polyguaiacol nanowires were successfully prepared via polymerization oxidation of guaiacol (o-methoxy phenol) by peroxidase enzyme in the presence of hydrogen peroxide at mild reaction conditions. The dimensions of the prepared nanowires were controlled by tuning the size and shape of the micelle structure via changing and controlling the type, chain length and molar concentrations of the ionic surfactant. The progress of the reaction and estimation of the size of soft micellar templates were followed by UV-Vis spectroscopy and dynamic light scattering (DLS). The resulting micelle encapsulated or purified polyguaiacol nanowires were characterized using transmission electron microscopy (TEM).

  14. Controlled nanopatterning of a polymerized ionic liquid in a strong electric field

    SciTech Connect

    Bocharova, Vera; Agapov, Alexander L.; Tselev, Alexander; Kumar, Rajeev; Berdzinski, Stefan; Strehmel, Veronika; Kisliuk, Alexander; Kravchenko, Ivan I.; Sumpter, Bobby G.; Sokolov, Alexei P.; Kalinin, Sergei V.; Strelcov, Evgheni; Collins, Liam

    2014-12-17

    Nanolithography has become a driving force in advancements of the modern day's electronics, allowing for miniaturization of devices and a steady increase of the calculation, power, and storage densities. Among various nanofabrication approaches, scanning probe techniques, including atomic force microscopy (AFM), are versatile tools for creating nanoscale patterns utilizing a range of physical stimuli such as force, heat, or electric field confined to the nanoscale. In this study, the potential of using the electric field localized at the apex of an AFM tip to induce and control changes in the mechanical properties of an ion containing polymer—a polymerized ionic liquid (PolyIL)—on a very localized scale is explored. In particular, it is demonstrated that by means of AFM, one can form topographical features on the surface of PolyIL-based thin films with a significantly lower electric potential and power consumption as compared to nonconductive polymer materials. Lastly,, by tuning the applied voltage and ambient air humidity, control over dimensions of the formed structures is reproducibly achieved.

  15. Controlled nanopatterning of a polymerized ionic liquid in a strong electric field

    DOE PAGES

    Bocharova, Vera; Agapov, Alexander L.; Tselev, Alexander; Kumar, Rajeev; Berdzinski, Stefan; Strehmel, Veronika; Kisliuk, Alexander; Kravchenko, Ivan I.; Sumpter, Bobby G.; Sokolov, Alexei P.; et al

    2014-12-17

    Nanolithography has become a driving force in advancements of the modern day's electronics, allowing for miniaturization of devices and a steady increase of the calculation, power, and storage densities. Among various nanofabrication approaches, scanning probe techniques, including atomic force microscopy (AFM), are versatile tools for creating nanoscale patterns utilizing a range of physical stimuli such as force, heat, or electric field confined to the nanoscale. In this study, the potential of using the electric field localized at the apex of an AFM tip to induce and control changes in the mechanical properties of an ion containing polymer—a polymerized ionic liquidmore » (PolyIL)—on a very localized scale is explored. In particular, it is demonstrated that by means of AFM, one can form topographical features on the surface of PolyIL-based thin films with a significantly lower electric potential and power consumption as compared to nonconductive polymer materials. Lastly,, by tuning the applied voltage and ambient air humidity, control over dimensions of the formed structures is reproducibly achieved.« less

  16. Ionic strength-dependent changes in tentacular ion exchangers with variable ligand density. I. Structural properties.

    PubMed

    Bhambure, Rahul; Gillespie, Christopher M; Phillips, Michael; Graalfs, Heiner; Lenhoff, Abraham M

    2016-09-01

    The ligand density critically affects the performance of ion-exchange resins in such measures as the adsorption capacity and transport characteristics. However, for tentacular and other polymer-modified exchangers, the mechanistic basis of the effect of ligand density on performance is not yet fully understood. In this study we map the ionic strength-dependent structural changes in tentacular cation exchangers with variable ligand densities as the basis for subsequent investigation of effects on functional properties. Inverse size-exclusion chromatography (ISEC), scanning electron microscopy (SEM) and small-angle x-ray scattering (SAXS) were used to assess the effect of ionic strength on the pore size and intraparticle architecture of resin variants with different ligand densities. Comparison of ISEC and cryo-SEM results shows a considerable reduction in average pore size with increasing ligand density; these methods also confirm an increase of average pore size at higher ionic strengths. SAXS analysis of ionic strength-dependent conformational changes in the grafted polyelectrolyte layer shows a characteristic ionomer peak at values of the scattering vector q (0.1-0.2Å(-1)) that depend on the ligand density and the ionic strength of the solution. This peak attribution reflects nanoscale changes in the structure of the grafted polyelectrolyte chains that can in turn be responsible for observed pore-size changes in the resins. Finally, salt breakthrough experiments confirm a stronger Donnan exclusion effect on pore accessibility for small ions in the high ligand density variant. PMID:27544749

  17. Correlating Humidity-Dependent Ionically Conductive Surface Area with Transport Phenomena in Proton-Exchange Membranes

    SciTech Connect

    He, Qinggang; Kusoglu, Ahmet; Lucas, Ivan T.; Clark, Kyle; Weber, Adam Z.; Kostecki, Robert

    2011-08-01

    The objective of this effort was to correlate the local surface ionic conductance of a Nafion? 212 proton-exchange membrane with its bulk and interfacial transport properties as a function of water content. Both macroscopic and microscopic proton conductivities were investigated at different relative humidity levels, using electrochemical impedance spectroscopy and current-sensing atomic force microscopy (CSAFM). We were able to identify small ion-conducting domains that grew with humidity at the surface of the membrane. Numerical analysis of the surface ionic conductance images recorded at various relative humidity levels helped determine the fractional area of ion-conducting active sites. A simple square-root relationship between the fractional conducting area and observed interfacial mass-transport resistance was established. Furthermore, the relationship between the bulk ionic conductivity and surface ionic conductance pattern of the Nafion? membrane was examined.

  18. Anion exchange membrane prepared from simultaneous polymerization and quaternization of 4-vinyl pyridine for non-aqueous vanadium redox flow battery applications

    NASA Astrophysics Data System (ADS)

    Maurya, Sandip; Shin, Sung-Hee; Sung, Ki-Won; Moon, Seung-Hyeon

    2014-06-01

    A simple, single step and environmentally friendly process is developed for the synthesis of anion exchange membrane (AEM) by simultaneous polymerization and quaternization, unlike the conventional membrane synthesis which consists of separate polymerization and quaternization step. The membrane synthesis is carried out by dissolving polyvinyl chloride (PVC) in cyclohexanone along with 4-vinyl pyridine (4VP) and 1,4-dibromobutane (DBB) in the presence of thermal initiator benzoyl peroxide, followed by film casting to get thin and flexible AEMs. The membrane properties such as ion exchange capacity, ionic conductivity and swelling behaviour are tuned by varying the degree of crosslinking. These AEMs exhibit low vanadium permeability, while retaining good dimensional and chemical stability in an electrolyte solution, making them appropriate candidates for non-aqueous vanadium acetylacetonate redox flow battery (VRFB) applications. The optimized membrane displays ion exchange capacity and ionic conductivity of 2.0 mequiv g-1 and 0.105 mS cm-1, respectively, whereas the efficiency of 91.7%, 95.7% and 87.7% for coulombic, voltage and energy parameter in non-aqueous VRFB, respectively. This study reveals that the non-aqueous VRFB performance is greatly influenced by membrane properties; therefore the optimal control over the membrane properties is advantageous for the improved performance.

  19. Influence of Ionic Liquids on the Selectivity of Ion Exchange-Based Polymer Membrane Sensing Layers.

    PubMed

    Mendecki, Lukasz; Callan, Nicole; Ahern, Meghan; Schazmann, Benjamin; Radu, Aleksandar

    2016-01-01

    The applicability of ion exchange membranes is mainly defined by their permselectivity towards specific ions. For instance, the needed selectivity can be sought by modifying some of the components required for the preparation of such membranes. In this study, a new class of materials -trihexyl(tetradecyl)phosphonium based ionic liquids (ILs) were used to modify the properties of ion exchange membranes. We determined selectivity coefficients for iodide as model ion utilizing six phosphonium-based ILs and compared the selectivity with two classical plasticizers. The dielectric properties of membranes plasticized with ionic liquids and their response characteristics towards ten different anions were investigated using potentiometric and impedance measurements. In this large set of data, deviations of obtained selectivity coefficients from the well-established Hofmeister series were observed on many occasions thus indicating a multitude of applications for these ion-exchanging systems. PMID:27438837

  20. Influence of Ionic Liquids on the Selectivity of Ion Exchange-Based Polymer Membrane Sensing Layers.

    PubMed

    Mendecki, Lukasz; Callan, Nicole; Ahern, Meghan; Schazmann, Benjamin; Radu, Aleksandar

    2016-01-01

    The applicability of ion exchange membranes is mainly defined by their permselectivity towards specific ions. For instance, the needed selectivity can be sought by modifying some of the components required for the preparation of such membranes. In this study, a new class of materials -trihexyl(tetradecyl)phosphonium based ionic liquids (ILs) were used to modify the properties of ion exchange membranes. We determined selectivity coefficients for iodide as model ion utilizing six phosphonium-based ILs and compared the selectivity with two classical plasticizers. The dielectric properties of membranes plasticized with ionic liquids and their response characteristics towards ten different anions were investigated using potentiometric and impedance measurements. In this large set of data, deviations of obtained selectivity coefficients from the well-established Hofmeister series were observed on many occasions thus indicating a multitude of applications for these ion-exchanging systems.

  1. Influence of Ionic Liquids on the Selectivity of Ion Exchange-Based Polymer Membrane Sensing Layers

    PubMed Central

    Mendecki, Lukasz; Callan, Nicole; Ahern, Meghan; Schazmann, Benjamin; Radu, Aleksandar

    2016-01-01

    The applicability of ion exchange membranes is mainly defined by their permselectivity towards specific ions. For instance, the needed selectivity can be sought by modifying some of the components required for the preparation of such membranes. In this study, a new class of materials –trihexyl(tetradecyl)phosphonium based ionic liquids (ILs) were used to modify the properties of ion exchange membranes. We determined selectivity coefficients for iodide as model ion utilizing six phosphonium-based ILs and compared the selectivity with two classical plasticizers. The dielectric properties of membranes plasticized with ionic liquids and their response characteristics towards ten different anions were investigated using potentiometric and impedance measurements. In this large set of data, deviations of obtained selectivity coefficients from the well-established Hofmeister series were observed on many occasions thus indicating a multitude of applications for these ion-exchanging systems. PMID:27438837

  2. Electrochemical fabrication of polymerized imidazole-based ionic liquid bearing pyrrole moiety for sensitive determination of hexestrol in chicken meat.

    PubMed

    Chen, Xuemin; Ma, Yanhui; Chen, Danchao; Ma, Ming; Li, Chunya

    2015-08-01

    1-[3-(tert-Butoxycarbonylamino)propyl]-3-[3-(N-pyrrole)propyl]imidazolium tetrafluoroborate [(t-Boc-APPPI)BF4], which is a novel pyrrolyl-functionalized ionic liquid, was synthesized and characterized. Subsequently, it was electrochemically deposited onto a glassy carbon electrode surface to fabricate a polymerized ionic liquid film electrode. X-ray photoelectron spectroscopy, scanning electron microscope and electrochemical impedance spectroscopy were used to confirm the successful polymerization of ionic liquid. Voltammetric behaviors of hexestrol at the film electrode were investigated. The oxidation peak slightly shifted towards positive potential, however, dramatically increased in peak current. Experimental conditions for hexestrol determination were optimized. The oxidation peak current is linear with hexestrol concentration in the range of 1.0 × 10(-8)-1.0 × 10(-5) mol L(-1). The detection limit is estimated to be 2.1 × 10(-9) mol L(-1) (S/N=3). Hexestrol in chicken meat was determined using the film electrode with good accuracy.

  3. Spectroscopic method for the determination of the ionic site concentration in solvent polymeric membranes and membrane plasticizers.

    PubMed

    Gyurcsányi, Robert E; Lindner, Erno

    2002-08-15

    The built-in site density of either fixed sites or mobile hydrophobic ion sites determines whether a membrane is permselective for cations or anions of the sample. The molar ratio of the ionophore to the intrinsic or added ionic sites in an ion-selective membrane significantly influences the potentiometric response of ionophore-based electrodes. Consequently, full knowledge of the "site inventory" in an ion-selective membrane maybe essential when new, uncharacterized polymers or plasticizers are implemented for ion-selective electrode fabrication. A simple spectroscopic method was developed for the fast and accurate determination of the ionic site concentration (covalently attached functionalized groups or impurities) in plasticized polymeric membranes and membrane plasticizers. The method is based on the determination of the degree of protonation of hydrogen ion-selective chromoionophores incorporated into these membranes or dissolved in the membrane plasticizers. In electroneutral membranes, the concentration of the positively charged, protonated ionophore and the total concentration of negative sites are equal. The method was applied for the determination of ionic sites (both positively and negatively charged) in PVC materials (different purity grade, and bearing various functional groups), polyurethanes (aliphatic, aromatic, and polycarbonate-based), and selected Fluka plasticizers (2-nitrophenyl octyl ether and 2-ethylhexyl sebacate). The technique proved to be appropriate for fast quantification of ionic impurities in hydrophobic, optically transparent materials.

  4. The Effect of Microporous Polymeric Support Modification on Surface and Gas Transport Properties of Supported Ionic Liquid Membranes

    PubMed Central

    Akhmetshina, Alsu A.; Davletbaeva, Ilsiya M.; Grebenschikova, Ekaterina S.; Sazanova, Tatyana S.; Petukhov, Anton N.; Atlaskin, Artem A.; Razov, Evgeny N.; Zaripov, Ilnaz I.; Martins, Carla F.; Neves, Luísa A.; Vorotyntsev, Ilya V.

    2015-01-01

    Microporous polymers based on anionic macroinitiator and toluene 2,4-diisocyanate were used as a support for 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N]) immobilization. The polymeric support was modified by using silica particles associated in oligomeric media, and the influence of the modifier used on the polymeric structure was studied. The supported ionic liquid membranes (SILMs) were tested for He, N2, NH3, H2S, and CO2 gas separation and ideal selectivities were calculated. The high values of ideal selectivity for ammonia-based systems with permanent gases were observed on polymer matrixes immobilized with [bmim][PF6] and [emim][Tf2N]. The modification of SILMs by nanosize silica particles leads to an increase of NH3 separation relatively to CO2 or H2S. PMID:26729177

  5. The Effect of Microporous Polymeric Support Modification on Surface and Gas Transport Properties of Supported Ionic Liquid Membranes.

    PubMed

    Akhmetshina, Alsu A; Davletbaeva, Ilsiya M; Grebenschikova, Ekaterina S; Sazanova, Tatyana S; Petukhov, Anton N; Atlaskin, Artem A; Razov, Evgeny N; Zaripov, Ilnaz I; Martins, Carla F; Neves, Luísa A; Vorotyntsev, Ilya V

    2015-12-30

    Microporous polymers based on anionic macroinitiator and toluene 2,4-diisocyanate were used as a support for 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF₆]) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf₂N]) immobilization. The polymeric support was modified by using silica particles associated in oligomeric media, and the influence of the modifier used on the polymeric structure was studied. The supported ionic liquid membranes (SILMs) were tested for He, N₂, NH₃, H₂S, and CO₂ gas separation and ideal selectivities were calculated. The high values of ideal selectivity for ammonia-based systems with permanent gases were observed on polymer matrixes immobilized with [bmim][PF₆] and [emim][Tf₂N]. The modification of SILMs by nanosize silica particles leads to an increase of NH₃ separation relatively to CO₂ or H₂S.

  6. Synthesis of Proton-Exchange Membranes by a Plasma Polymerization Technique

    NASA Astrophysics Data System (ADS)

    Jiang, Zhongqing; Meng, Yuedong; Shi, Yicai

    2008-08-01

    An after-glow capacitively coupled discharge technique has been used to fabricate ultra-thin proton-exchange composite membranes in a plasma polymerization reactor, where styrene and acrylic acid are used as starting materials. During the preparation, the energy of the ionized particles extracted from the radio frequency glow discharge region to the plasma polymerization region can be easily controlled by adjusting the bias voltage applied to the screen grids and substrate. Therefore, the degradation of monomers can be effectively avoided, and the contents of the proton exchange groups on the obtained membranes could reach to a higher extent. The synthesized membranes are dense with uniform structure and are demonstrated as good proton conductors.

  7. Ionic polymeric micelles based on chitosan and fatty acids and intended for wound healing. Comparison of linoleic and oleic acid.

    PubMed

    Bonferoni, M C; Sandri, G; Dellera, E; Rossi, S; Ferrari, F; Mori, M; Caramella, C

    2014-05-01

    Chitosan is well known for its positive properties in wound healing. Also unsaturated fatty acids are described as able to accelerate tissue repairing mechanisms. In this work hydrophobically modified chitosan was obtained by ionic interaction with either oleic or linoleic acid. In aqueous environment self-assembling into nanoparticles occurred. The presence of hydrophobic domains, similar to those present in polymeric micelles, was demonstrated by changes in pyrene spectra. Both oleate and linoleate derivatives showed mucoadhesion behaviour. Cytotoxicity tests on human dermal fibroblasts demonstrated good biocompatibility of especially oleate derivatives. Clarithromycin, a poorly soluble model drug proposed for use in infected wounds was successfully encapsulated in both oleic and linoleic based polymeric micelles. The ionic structure of the carriers is responsible for their loosening at neutral pH and in the presence of salts. This behaviour should impair parenteral administration of the systems, but can be useful for topical delivery where the micelle components, chitosan and fatty acid, can play a positive role in dermal regeneration and tissue repairing.

  8. Ionic Liquid-Based Polymer Electrolytes via Surfactant-Assisted Polymerization at the Plasma-Liquid Interface.

    PubMed

    Tran, Quoc Chinh; Bui, Van-Tien; Dao, Van-Duong; Lee, Joong-Kee; Choi, Ho-Suk

    2016-06-29

    We first report an innovative method, which we refer to as interfacial liquid plasma polymerization, to chemically cross-link ionic liquids (ILs). By this method, a series of all-solid state, free-standing polymer electrolytes is successfully fabricated where ILs are used as building blocks and ethylene oxide-based surfactants are employed as an assisted-cross-linking agent. The thickness of the films is controlled by the plasma exposure time or the ratio of surfactant to ILs. The chemical structure and properties of the polymer electrolyte are characterized by scanning electron microscopy (SEM), Fourier transformation infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) spectroscopy, X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), and electrochemical impedance spectroscopy (EIS). Importantly, the underlying polymerization mechanism of the cross-linked IL-based polymer electrolyte is studied to show that fluoroborate or halide anions of ILs together with the aid of a small amount of surfactants having ethylene oxide groups are necessary to form cross-linked network structures of the polymer electrolyte. The ionic conductivity of the obtained polymer electrolyte is 2.28 × 10(-3) S·cm(-1), which is a relatively high value for solid polymer electrolytes synthesized at room temperature. This study can serve as a cornerstone for developing all-solid state polymer electrolytes with promising properties for next-generation electrochemical devices.

  9. Ionic polymer-metal composite actuators employing sulfonated poly (styrene-ethylene-butylene-styrene) as ionic-exchange membranes

    NASA Astrophysics Data System (ADS)

    Wang, Xuan-Lun; Oh, Il-Kwon; Lu, Jun; Ju, Jin-Hun; Lee, Sun-Woo

    2007-07-01

    There is growing interest in biomimetic motions by employing ionic polymer-metal composites (IPMCs) as the candidates for the fabrication of artificial muscle. However, the membrane materials currently used in IPMC actuators have been limited to a few commercially available perfluorinated ionic polymers, such as Nafion, and they suffer from several shortcomings among which their high cost presents a major obstacle for wide application. With excellent proton conductivity and high water uptake capacity, commercially available Sulfonated poly (styrene-ethylene-butylene-styrene) (SEBS) of low cost has been investigated for many years as a fuel cell membrane. Herein, we report the preparation of a novel IPMC actuator based on the sulfonated SEBS (SSEBS) membrane. The platinum electrodes of the SEBS actuators were obtained with electroless plating procedure, and the cation exchange with lithium was performed by soaking the composite membranes into a 1.5N LiCl solution. The surface and cross-sectional morphologies of the SSEBS actuators were observed by using scanning electron microscopy (SEM), which revealed that the platinum layer up to 8µm was deposited on the top and bottom surfaces of the SSEBS membrane. The electromechanical bending responses were investigated under alternating current excitations with various driving frequencies and voltage amplitudes, which showed high electrical strains under sinusoidal signal. The effect of the membrane thickness on the performance of the actuators was also addressed in this presentation. This kind of IPMC has great potentials for the applications in biomimetic sensors and actuators, which can be utilized to mimic the locomotion of fish and insects and can be applied to micro-robots and bio-medical devices as well.

  10. Polymeric ionic liquid coatings versus commercial solid-phase microextraction coatings for the determination of volatile compounds in cheeses.

    PubMed

    Trujillo-Rodríguez, María J; Yu, Honglian; Cole, William T S; Ho, Tien D; Pino, Verónica; Anderson, Jared L; Afonso, Ana M

    2014-04-01

    The extraction performance of four polymeric ionic liquid (PIL)-based solid-phase microextraction (SPME) coatings has been studied and compared to that of commercial SPME coatings for the extraction of 16 volatile compounds in cheeses. The analytes include 2 free fatty acids, 2 aldehydes, 2 ketones and 10 phenols and were determined by headspace (HS)-SPME coupled to gas chromatography (GC) with flame-ionization detection (FID). The PIL-based coatings produced by UV co-polymerization were more efficient than PIL-based coatings produced by thermal AIBN polymerization. Partition coefficients of analytes between the sample and the coating (Kfs) were estimated for all PIL-based coatings and the commercial SPME fiber showing the best performance among the commercial fibers tested: carboxen-polydimethylsyloxane (CAR-PDMS). For the PIL-based fibers, the highest K(fs) value (1.96 ± 0.03) was obtained for eugenol. The normalized calibration slope, which takes into account the SPME coating thickness, was also used as a simpler approximate tool to compare the nature of the coating within the determinations, with results entirely comparable to those obtained with estimated K(fs) values. The PIL-based materials obtained by UV co-polymerization containing the 1-vinyl-3-hexylimidazolium chloride IL monomer and 1,12-di(3-vinylimiazolium)dodecane dibromide IL crosslinker exhibited the best performance in the extraction of the select analytes from cheeses. Despite a coating thickness of only 7 µm, this copolymeric sorbent coating was capable of quantitating analytes in HS-SPME in a 30 to 2000 µg L(-1) concentration range, with correlation coefficient (R) values higher than 0.9938, inter-day precision values (as relative standard deviation in %) varying from 6.1 to 20%, and detection limits down to 1.6 µg L(-1). PMID:24607122

  11. A mechanism for enhancing ionic accessibility into selective ion exchange resins

    SciTech Connect

    Alexandratos, S.D.; Shelley, C.A.; Horwitz, E.P.; Chiarizia, R.

    1998-07-01

    A bifunctional monophosphonic/sulfonic acid ion exchange resin with high capacity has been synthesized. Metal ion studies have been carried out with europium, americium, and ferric nitrate in solutions of varying acidity, with and without sodium nitrate added. The bifunctional resin complexes far higher levels of Eu(III) from 0.5 and 1 N nitric acid than the monofunctional phosphonic acid resin. It is postulated that the sulfonic acid ligand provides an access mechanism for the metal ions into the polymer matrix by hydrating the matrix and preventing its collapse in high ionic strength solutions thus allowing for rapid ionic complexation by the selective phosphonic acid ligands. The bifunctional monophosphonic/sulfonic acid resin has both ligands bound to a polystyrene support. It complexes higher levels of metal ions than a comparable resin differing only by having the monophosphonic acid ligand directly bound to the C-C backbone. Results are compared to a diphosphonic/sulfonic acid resin.

  12. The Effects of Temperature upon Contraction and Ionic Exchange in Rabbit Ventricular Myocardium

    PubMed Central

    Langer, G. A.; Brady, A. J.

    1968-01-01

    The mechanical responses (active and resting tension, dP/dt, TPT) and ionic exchange characteristics (Ca++, K+, Na+) which follow upon a variation in temperature, rate, and [K+]0 were studied in the rabbit papillary muscle and arterially perfused rabbit interventricular setpum. Abrupt changes in temperature provided a means of separating the contributions of rate of development (intensity) of active state and duration of active state to total active tension development (approximated by isometric tension). Threefold changes in duration of active state with proportional changes in active tension can be induced without evidence for alteration of Ca++, K+, or Na+ exchange. Abrupt cooling produced a moderate (∼15%) increase of dP/dt which suggests an augmentation of active state intensity. Evidence is presented to suggest that this increase of dP/dt is based upon an increase in membrane Ca++ concentration which occurs secondary to inhibition of active Na+ transport. The alterations in ionic exchange and active state produced by variation of temperature are discussed in terms of a five-component control system. PMID:5682487

  13. Precision synthesis of poly(ionic liquid)-based block copolymers by cobalt-mediated radical polymerization and preliminary study of their self-assembling properties.

    PubMed

    Coupillaud, Paul; Fèvre, Maréva; Wirotius, Anne-Laure; Aissou, Karim; Fleury, Guillaume; Debuigne, Antoine; Detrembleur, Christophe; Mecerreyes, David; Vignolle, Joan; Taton, Daniel

    2014-02-01

    A poly(ionic liquid)-based block copolymer (PIL BCP), namely, poly(vinyl acetate)-b-poly(N-vinyl-3-butylimidazolium bromide), PVAc-b-PVBuImBr, is synthesized by sequential cobalt-mediated radical polymerization (CMRP). A PVAc precursor is first prepared at 30 °C in bulk by CMRP of VAc, using bis(acetylacetonato)cobalt(II), Co(acac)2, and a radical source (V-70). Growth of PVBuImBr from PVAc-Co(acac)2 is accomplished by CMRP in DMF/MeOH (2:1, v/v). This PIL BCP self-assembles in the sub-micron size range into aggregated core-shell micelles in THF, whereas polymeric vesicles are observed in water, as evidenced by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Thin-solid sample cut from raw materials analyzed by TEM shows an ordered lamellar organization by temperature-dependent synchrotron small-angle X-ray scattering (SAXS). Anion exchange can be accomplished to achieve the corresponding PIL BCP with bis(trifluorosulfonyl)imide (Tf2 N(-)) anions, which also gives rise to an ordered lamellar phase in bulk samples. A complete suppression of SAXS second-order reflection suggests that this compound has a symmetric volume fraction (f ≈ 0.5). SAXS characterization of both di- and triblock PIL BCP analogues previously reported also shows a lamellar phase of very similar behavior, with only an increase of the period by about 8% at 60 °C.

  14. Stable Deep Doping of Vapor-Phase Polymerized Poly(3,4-ethylenedioxythiophene)/Ionic Liquid Supercapacitors.

    PubMed

    Karlsson, Christoffer; Nicholas, James; Evans, Drew; Forsyth, Maria; Strømme, Maria; Sjödin, Martin; Howlett, Patrick C; Pozo-Gonzalo, Cristina

    2016-08-23

    Liquid-solution polymerization and vapor-phase polymerization (VPP) have been used to manufacture a series of chloride- and tosylate-doped poly(3,4-ethylenedioxythiophene) (PEDOT) carbon paper electrodes. The electrochemistry, specific capacitance, and specific charge were determined for single electrodes in 1-ethyl-3-methylimidazolium dicyanamide (emim dca) ionic liquid electrolyte. VPP-PEDOT exhibits outstanding properties with a specific capacitance higher than 300 F g(-1) , the highest value reported for a PEDOT-based conducting polymer, and doping levels as high as 0.7 charges per monomer were achieved. Furthermore, symmetric PEDOT supercapacitor cells with the emim dca electrolyte exhibited a high specific capacitance (76.4 F g(-1) ) and high specific energy (19.8 Wh kg(-1) ). A Ragone plot shows that the VPP-PEDOT cells combine the high specific power of conventional ("pure") capacitors with the high specific energy of batteries, a highly sought-after target for energy storage. PMID:27325487

  15. Stable Deep Doping of Vapor-Phase Polymerized Poly(3,4-ethylenedioxythiophene)/Ionic Liquid Supercapacitors.

    PubMed

    Karlsson, Christoffer; Nicholas, James; Evans, Drew; Forsyth, Maria; Strømme, Maria; Sjödin, Martin; Howlett, Patrick C; Pozo-Gonzalo, Cristina

    2016-08-23

    Liquid-solution polymerization and vapor-phase polymerization (VPP) have been used to manufacture a series of chloride- and tosylate-doped poly(3,4-ethylenedioxythiophene) (PEDOT) carbon paper electrodes. The electrochemistry, specific capacitance, and specific charge were determined for single electrodes in 1-ethyl-3-methylimidazolium dicyanamide (emim dca) ionic liquid electrolyte. VPP-PEDOT exhibits outstanding properties with a specific capacitance higher than 300 F g(-1) , the highest value reported for a PEDOT-based conducting polymer, and doping levels as high as 0.7 charges per monomer were achieved. Furthermore, symmetric PEDOT supercapacitor cells with the emim dca electrolyte exhibited a high specific capacitance (76.4 F g(-1) ) and high specific energy (19.8 Wh kg(-1) ). A Ragone plot shows that the VPP-PEDOT cells combine the high specific power of conventional ("pure") capacitors with the high specific energy of batteries, a highly sought-after target for energy storage.

  16. Crystalline, Glassy and Polymeric Electrolytes:. Similarities and Differences in Ionic Transport Mechanisms

    NASA Astrophysics Data System (ADS)

    Souquet, Jean Louis

    2006-06-01

    Ionocovalent crystals or glasses as well as molten salts or salt polymer complexes are currently studied as electrolytes for high energy density batteries. Their large Red/Ox stability range results from their thermodynamic or kinetic characteristics. For all these electrolytes, charge carriers are the consequence of local deviations from electroneutrality, identified as point defects for ionic crystals or partial dissociation in disordered structures. The charge carriers formation derives from a similar activated process. The main difference comes from the migration process, which depends on the dynamic properties of the surrounding medium. When the structural relaxation time is large, an activated process, mainly enthalpic, prevails for charge carriers migration. It is the usual case for ionic crystals or glasses. In the liquid or overcooled liquid states, the structural relaxation time of the medium is shorter that the time required for the activated migration process to occur and a local reorganization of the medium vanishes the energy barrier and provides the free volume necessary to ionic migration. In that case, the migration is mainly an entropic process. The configurational entropy necessary to this process decreases with temperature and vanishes at the so called ideal glass transition temperature which can be estimated by extrapolation of the transport properties or of the thermodynamic characteristics of the medium. However, at the experiment time scale, this configurational entropy disappears at a somewhat higher temperature, the glass transition temperature at which the structural relaxation time corresponds to the measurement time. Some glass forming ionic melts studied in a large temperature scale, over and below the glass transition temperature, evidence the two, enthalpic and entropic, migration mechanisms, allowing the determination of the thermodynamic characteristics of the charge carriers formation and migration. Some recent results indicate

  17. Separation of tryptophan enantiomers by ligand-exchange chromatography with novel chiral ionic liquids ligand.

    PubMed

    Qing, Haiqun; Jiang, Xinyu; Yu, Jingang

    2014-03-01

    Chiral ionic liquids (CILs) with amino acids as cations have been applied as novel chiral ligands coordinated with Cu(2+) to separate tryptophan enantiomers in ligand exchange chromatography. Four kinds of amino acid ionic liquids, including [L-Pro][CF3COO], [L-Pro][NO3], [L-Pro]2[SO4], and [L-Phe][CF3COO] were successfully synthesized and used for separation of tryptophan enantiomers. To optimize the separation conditions, [L-Pro][CF3COO] was selected as the model ligand. Some factors influencing the efficiency of chiral separation, such as copper ion concentration, CILs concentration, methanol ratio (methanol/H2O, v/v), and pH, were investigated. The obtained optimal separation conditions were as follows: 8.0 mmol/L Cu(OAc)2, 4.0 mmol/L [L-Pro][CF3COO], and 20% (v/v) methanol at pH 3.6. Under the optimum conditions, acceptable enantioseparation of tryptophan enantiomers could be observed with a resolution of 1.89. The results demonstrate the good applicability of CILs with amino acids as cations for chiral separation. Furthermore, a comparative study was also conducted for exploring the mechanism of the CILs as new ligands in ligand exchange chromatography.

  18. Preparation of an adsorbent based on polymeric ionic liquid for the simultaneous extraction of acidic, basic and neutral pollutants.

    PubMed

    Chen, Lei; Huang, Xiaojia

    2016-09-30

    In this study, coextraction of acidic, basic and neutral pollutants was realized with a new adsorbent based on polymeric ionic liquid (PIL). In the presence of a porogen solvent containing 1-propanol and 1,4-butanediol, an ionic liquid, 1-vinyl-3-octylimidazolium tetrafluoraborate was used as monomer to copolymerize with dual cross-linkers (divinylbenzene and N,N-methylene-bisacrylamide) to form the adsorbent for stir cake sorptive extraction (SCSE). Phenols, aromatic amines and parabens were selected as acidic, basic and neutral model analytes, respectively. The effects of preparation conditions and extraction parameters on the extraction performance of SCSE/PIL were investigated thoroughly. Under the optimized conditions, the prepared adsorbent showed satisfactory coextraction performance to the selected analytes with multiply interactions. At the same time, simple and sensitive analytical method for simultaneous determination of phenols, aromatic amines and parabens in environmental water samples was developed by the combination of SCSE/PIL with high-performance liquid chromatography with diode array detection. Low limits of detection (S/N=3) and quantification limits (S/N=10) of the proposed method for the targeted analytes were achieved within the range of 0.064-0.30μg/L and 0.21-0.99μg/L, respectively. The precision of the proposed method was evaluated in terms of intra- and inter-assay variability calculated as relative standard deviation (RSD), and it was found that the RSD values were all below 10%. Ultimately, the applicability of developed method was successfully confirmed by analyzing lake, reservoir and river water samples. Recoveries obtained for the determination of targeted analytes in spiking samples ranged from 70.0% to 112%, with RSDs within the range of 1.6-9.8%. PMID:27613147

  19. Ligand exchange in ionic systems and its effect on silver nucleation and growth.

    PubMed

    Abbott, Andrew P; Azam, Muhammad; Frisch, Gero; Hartley, Jennifer; Ryder, Karl S; Saleem, Saima

    2013-10-28

    The electrodeposition of metals from ionic solutions is intrinsically linked to the reactivity of the solute ions. When metal salts dissolve, the exchange of the anion with the molecular and ionic components from solution affects the speciation and therefore the characteristics of metal reduction. This study investigates the nucleation mechanism, deposition kinetics, metal speciation and diffusion coefficients of silver salts dissolved in Deep Eutectic Solvents. The electrochemical reduction of AgCl, AgNO3 and Ag2O is studied in 1 : 2 choline chloride : ethylene glycol and 1 : 2 choline chloride : urea. Cyclic voltammetry is used to evaluate electrochemical kinetics. Detailed analysis of chronoamperometric data shows that silver deposits form via multiple 3D nucleation with mass transport controlled hemispherical growth. The nucleation mechanism was found to be potential dependent, varying from progressive to instantaneous as the reduction potential becomes more cathodic. Diffusion coefficients are determined using three different methods. Trends are rationalised in terms of solvent viscosity and silver speciation analysis with EXAFS. The morphology of electroreduced silver is investigated with scanning electron microscopy and shows that deposits from the urea based liquid form more dense morphologies than those from the ethylene glycol based liquid. PMID:24019028

  20. Water uptake, ionic conductivity and swelling properties of anion-exchange membrane

    SciTech Connect

    Duan, QJ; Ge, SH; Wang, CY

    2013-12-01

    Water uptake, ionic conductivity and dimensional change of the anion-exchange membrane made by Tokuyama Corporation (A201 membrane) are investigated at different temperatures and water activities. Specifically, the amount of water taken up by membranes exposed to water vapor and membranes soaked in liquid water is determined. The water uptake of the A201 membrane increases with water content as well as temperature. In addition, water sorption data shows Schroeder's paradox for the AEMs investigated. The swelling properties of the A201 membrane exhibit improved dimensional stability compared with Nafion membrane. Water sorption of the A201 membrane occurs with a substantial negative excess volume of mixing. The threshold value of hydrophilic fraction in the A201 membrane for ionic conductivity is around 0.34, above which, the conductivity begins to rise quickly. This indicates that a change in the connectivity of the hydrophilic domains occurs when hydrophilic fraction approaches 0.34. (C) 2013 Elsevier B.V. All rights reserved.

  1. Biofouling on polymeric heat exchanger surfaces with E. coli and native biofilms.

    PubMed

    Pohl, S; Madzgalla, M; Manz, W; Bart, H J

    2015-01-01

    The biofouling affinity of different polymeric surfaces (polypropylene, polysulfone, polyethylene terephthalate, and polyether ether ketone) in comparison to stainless steel (SS) was studied for the model bacterium Escherichia coli K12 DSM 498 and native biofilms originating from Rhine water. The biofilm mass deposited on the polymer surfaces was minimized by several magnitudes compared to SS. The cell count and the accumulated biomass of E. coli on the polymer surfaces showed an opposing linear trend. The promising low biofilm formation on the polymers is attributed to the combination of inherent surface properties (roughness, surface energy and hydrophobicity) when compared to SS. The fouling characteristics of E. coli biofilms show good conformity with the more complex native biofilms investigated. The results can be utilized for the development of new polymer heat exchangers when using untreated river water as coolant or for other processes needing antifouling materials. PMID:26479780

  2. Ion exchange fabric synthesized by graft polymerization and its application to ultra-pure water production

    NASA Astrophysics Data System (ADS)

    Takeda, T.; Tamada, M.; Seko, N.; Ueki, Y.

    2010-03-01

    Ion exchange fabric (IEF) having the functional group of sulfonic acid was synthesized by radiation grafting of glycidyl methacrylate on a polyethylene nonwoven fabric and subsequent chemical modification. Total organic carbon eluted from the resulting IEF could be reduced to the concentration less than 1 ppb after washing with organic solvents. Adsorption performance of the obtained IEF was evaluated by 10 ppb Na + solution. The column packed IEF, 7 mm in diameter and 20 mm high, could remove the Na + at the distribution coefficient of 1.2×10 7 at linear velocity of 400 m/h. At column height of 95 mm, the breakthrough point reached 2.0×10 5 in bed volume and the degree of column utilization was improved up to 18.7%. From these results, the IEF synthesized by graft polymerization was considered to be applicable for water purification in ultra-pure water production.

  3. Biofouling on polymeric heat exchanger surfaces with E. coli and native biofilms.

    PubMed

    Pohl, S; Madzgalla, M; Manz, W; Bart, H J

    2015-01-01

    The biofouling affinity of different polymeric surfaces (polypropylene, polysulfone, polyethylene terephthalate, and polyether ether ketone) in comparison to stainless steel (SS) was studied for the model bacterium Escherichia coli K12 DSM 498 and native biofilms originating from Rhine water. The biofilm mass deposited on the polymer surfaces was minimized by several magnitudes compared to SS. The cell count and the accumulated biomass of E. coli on the polymer surfaces showed an opposing linear trend. The promising low biofilm formation on the polymers is attributed to the combination of inherent surface properties (roughness, surface energy and hydrophobicity) when compared to SS. The fouling characteristics of E. coli biofilms show good conformity with the more complex native biofilms investigated. The results can be utilized for the development of new polymer heat exchangers when using untreated river water as coolant or for other processes needing antifouling materials.

  4. Preparation of minor actinides targets or blankets by means of ionic exchange resin

    NASA Astrophysics Data System (ADS)

    Picart, S.; Mokhtari, H.; Ramière, I.; Jobelin, I.

    2010-03-01

    The conversion of minor actinides to fuel starting materials for transmutation in a closed nuclear cycle is a big challenge for the next decades and the development of Gen(IV) nuclear systems. Conversion routes are numerous, but one needs to prove that they can be adapted to handle minor actinides. One of them is called the resin process and is particularly attractive because it stands for a "dustless" process as it produces microspheres of oxide or carbide after thermal treatment of the loaded resin. The study presented herein focuses on the experiments and tests which enable us to optimize the fixation of minor actinides onto ionic exchange resin and their carbonization into oxide type materials.

  5. Imidazolium-Based Polymeric Materials as Alkaline Anion-Exchange Fuel Cell Membranes

    NASA Technical Reports Server (NTRS)

    Narayan, Sri R.; Yen, Shiao-Ping S.; Reddy, Prakash V.; Nair, Nanditha

    2012-01-01

    Polymer electrolyte membranes that conduct hydroxide ions have potential use in fuel cells. A variety of polystyrene-based quaternary ammonium hydroxides have been reported as anion exchange fuel cell membranes. However, the hydrolytic stability and conductivity of the commercially available membranes are not adequate to meet the requirements of fuel cell applications. When compared with commercially available membranes, polystyrene-imidazolium alkaline membrane electrolytes are more stable and more highly conducting. At the time of this reporting, this has been the first such usage for imidazolium-based polymeric materials for fuel cells. Imidazolium salts are known to be electrochemically stable over wide potential ranges. By controlling the relative ratio of imidazolium groups in polystyrene-imidazolium salts, their physiochemical properties could be modulated. Alkaline anion exchange membranes based on polystyrene-imidazolium hydroxide materials have been developed. The first step was to synthesize the poly(styrene-co-(1-((4-vinyl)methyl)-3- methylimidazolium) chloride through a free-radical polymerization. Casting of this material followed by in situ treatment of the membranes with sodium hydroxide solutions provided the corresponding hydroxide salts. Various ratios of the monomers 4-chloromoethylvinylbenzine (CMVB) and vinylbenzine (VB) provided various compositions of the polymer. The preferred material, due to the relative ease of casting the film, and its relatively low hygroscopic nature, was a 2:1 ratio of CMVB to VB. Testing confirmed that at room temperature, the new membranes outperformed commercially available membranes by a large margin. With fuel cells now in use at NASA and in transportation, and with defense potential, any improvement to fuel cell efficiency is a significant development.

  6. Hollow fiber membrane-coated functionalized polymeric ionic liquid capsules for direct analysis of estrogens in milk samples.

    PubMed

    Feng, Juanjuan; Sun, Min; Bu, Yanan; Luo, Chuannan

    2016-02-01

    Protein removal process is always time-consuming for the analysis of milk samples. In this work, hollow fiber membrane-coated functionalized polymeric ionic liquid (HF-PIL) capsules were synthesized and used as solid-phase microextraction (SPME) sorbent for direct analysis of estrogens in milk samples. The functionalized PIL monolith sorbent was obtained by copolymerization between 1-(3-aminopropyl)-3-(4-vinylbenzyl)imidazolium 4-styrenesulfonate IL monomer and 1,6-di(3-vinylimidazolium) hexane bishexafluorophosphate IL-crosslinking agent. A group of four capsules were installed as SPME device, to determine four kinds of estrogens (estrone, diethylstilbestrol, hexestrol, and 17α-ethynylestradiol) in milk samples, coupled to high performance liquid chromatography. Extraction and desorption conditions were optimized to get satisfactory extraction efficiency. Good linearity was obtained in the range of 5-200 μg L(-1). The limits of detection were 1 μg L(-1) for diethylstilbestrol and 2 μg L(-1) for 17α-ethynylestradiol, estrone, and hexestrol. The present method was applied to analyze the model analytes in different milk samples. Relative recoveries were in the range of 85.5-112%. The HF-PIL SPME capsules showed satisfactory extraction efficiency and high resistance to sample matrix interference. PMID:26753984

  7. Hollow fiber membrane-coated functionalized polymeric ionic liquid capsules for direct analysis of estrogens in milk samples.

    PubMed

    Feng, Juanjuan; Sun, Min; Bu, Yanan; Luo, Chuannan

    2016-02-01

    Protein removal process is always time-consuming for the analysis of milk samples. In this work, hollow fiber membrane-coated functionalized polymeric ionic liquid (HF-PIL) capsules were synthesized and used as solid-phase microextraction (SPME) sorbent for direct analysis of estrogens in milk samples. The functionalized PIL monolith sorbent was obtained by copolymerization between 1-(3-aminopropyl)-3-(4-vinylbenzyl)imidazolium 4-styrenesulfonate IL monomer and 1,6-di(3-vinylimidazolium) hexane bishexafluorophosphate IL-crosslinking agent. A group of four capsules were installed as SPME device, to determine four kinds of estrogens (estrone, diethylstilbestrol, hexestrol, and 17α-ethynylestradiol) in milk samples, coupled to high performance liquid chromatography. Extraction and desorption conditions were optimized to get satisfactory extraction efficiency. Good linearity was obtained in the range of 5-200 μg L(-1). The limits of detection were 1 μg L(-1) for diethylstilbestrol and 2 μg L(-1) for 17α-ethynylestradiol, estrone, and hexestrol. The present method was applied to analyze the model analytes in different milk samples. Relative recoveries were in the range of 85.5-112%. The HF-PIL SPME capsules showed satisfactory extraction efficiency and high resistance to sample matrix interference.

  8. An understanding of enhanced osteoblast adhesion on various nanostructured polymeric and metallic materials prepared by ionic plasma deposition.

    PubMed

    Pareta, Rajesh A; Reising, Alexander B; Miller, Tiffany; Storey, Dan; Webster, Thomas J

    2010-03-01

    The development of new materials through novel surface modification techniques to enhance orthopedic implant lifetimes (hence, decreasing the need for revision surgery) is of great interest to the medical community. The purpose of this in vitro study was to treat common metallic implant materials [such as titanium (Ti) and a titanium alloy (Ti6Al4V)] and traditional polymeric materials (like polyethylene terephthalate, polyvinyl chloride, polyurethane, polytetrafluoroethylene, ultra-high molecular weight polyethylene (UHMWPE) and nylon) with either nanoparticulate alumina or titanium using novel (i) ionic plasma deposition (IPD) and (ii) nitrogen ion immersion plasma deposition (NIIPD) techniques. The treated surfaces were characterized by scanning electron microscopy, atomic force microscopy and surface energy, demonstrating greater nanoscale roughness on the modified surfaces regardless of the underlying material or coating applied. These surface-modified substrates were also tested for cytocompatibility properties with osteoblasts (or bone-forming cells). Results showed increased osteoblast adhesion on modified compared to control (traditional or untreated) materials. Since the adhesion of osteoblasts is the first crucial step for new bone synthesis, these results are very promising and suggest that the plasma deposition processes used in this study should be further investigated to improve the longevity of orthopedic implants.

  9. Swelling and Shrinking Properties of Thermo-Responsive Polymeric Ionic Liquid Hydrogels with Embedded Linear pNIPAAM

    PubMed Central

    Gallagher, Simon; Florea, Larisa; Fraser, Kevin J.; Diamond, Dermot

    2014-01-01

    In this study, varying concentrations of linear pNIPAAM have been incorporated for the first time into a thermo-responsive polymeric ionic liquid (PIL) hydrogel, namely tributyl-hexyl phosphonium 3-sulfopropylacrylate (P-SPA), to produce semi-interpenetrating polymer networks. The thermal properties of the resulting hydrogels have been investigated along with their thermo-induced shrinking and reswelling capabilities. The semi-interpenetrating networks (IPN) hydrogels were found to have improved shrinking and reswelling properties compared with their PIL counterpart. At elevated temperatures (50–80 °C), it was found that the semi-IPN with the highest concentration of hydrophobic pNIPAAM exhibited the highest shrinking percentage of ~40% compared to the conventional P-SPA, (27%). This trend was also found to occur for the reswelling measurements, with semi-IPN hydrogels producing the highest reswelling percentage of ~67%, with respect to its contracted state. This was attributed to an increase in water affinity due to the presence of hydrophilic pNIPAAM. Moreover, the presence of linear pNIPAAM in the polymer matrix leads to improved shrinking and reswelling response compared to the equivalent PIL. PMID:24681582

  10. Observation of antibacterial effect of biodegradable polymeric nanoparticles on Staphylococcus epidermidis biofilm using FE-SEM with an ionic liquid.

    PubMed

    Takahashi, Chisato; Ogawa, Noriko; Kawashima, Yoshiaki; Yamamoto, Hiromitsu

    2015-06-01

    We successfully visualized the antibacterial behavior of biodegradable polymeric nanoparticles (NPs) on a biofilm formed by Staphylococcus epidermidis using field emission scanning electron microscopy (FE-SEM). A hydrophilic ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]), was applied for observation using FE-SEM. The differences in adherence and penetration behavior of three types of NPs were revealed using this method and confocal laser scanning microscopy. Biodegradable poly(dl-lactide-co-glycolide) (PLGA) NPs were prepared by the emulsion solvent diffusion method. In this study, we treated the biofilm with three PLGA NPs: unmodified PLGA, PLGA modified with chitosan (CS) and clarithromycin (CAM)-loaded + CS-modified PLGA. The viability of S. epidermidis cells treated with PLGA NPs was estimated using the LIVE/DEAD BacLight kit to understand the antibacterial ability of each NP sample in a quantitative way. The results confirmed that CAM-loaded + CS-modified PLGA had high antibacterial ability on the biofilm. This novel observation technique would be useful in the development of drug formations and medical agents.

  11. Electrospun Pd nanoparticles loaded on Vulcan carbon/ conductive polymeric ionic liquid nanofibers for selective and sensitive determination of tramadol.

    PubMed

    Fathirad, Fariba; Mostafavi, Ali; Afzali, Daryoush

    2016-10-12

    In the present work a sensitive and selective electrochemical sensor was fabricated based on a glassy carbon electrode which has been modified with Pd nanoparticles loaded on Vulcan carbon/conductive polymeric ionic liquid composite nanofibers. The nanostructures were characterized by UV-Vis, FT-IR, FESEM, EDX and XRD techniques. The electrochemical study of the modified electrode, as well as its efficiency for the electrooxidation of tramadol was described in 0.1 M phosphate buffered solution (PBS) (pH 7.0) using cyclic voltammetry, linear sweep voltammetry, chronoamperometry and square wave voltammetry as diagnostic techniques. It has been found that application of the composite nanofibers result in a sensitivity enhancement and a considerable decrease in the anodic overpotential, leading to negative shifts about 200 mV in peak potential. The results exhibit a linear dynamic range from 0.05 μM to 200 μM and a detection limit of 0.015 μM for tramadol. Finally, the modified electrode was used for the determination of tramadol in pharmaceutical and biological samples.

  12. The effect of cation structure on the mesophase architecture of self-assembled and polymerized imidazolium-based ionic liquids.

    SciTech Connect

    Batra, D.; Seifert, S.; Firestone, M. A.; Materials Science Division

    2007-01-01

    The binary phase behavior of a series of imidazolium-based ionic liquids (ILs) has been investigated. In particular, the effect of two structural modifications of the imidazolium cation, alkyl chain length, and the introduction of a polymerizable acryloyl group at the alkyl chain terminus, has been studied using small angle X-ray scattering. Upon increasing water content, the non-polymerizable IL, 1-decyl-3-methylimidazolium chloride, adopts mesophase structures of predominately two-dimensional (2D) hexagonal symmetry, including structures intermediate in character between lamellae and 2D hexagonal micelles. Introduction of a photopolymerizable acryloyl functional group to form 1-(10-(acryloyloxy)decyl)-3-methylimidazolium chloride produces a rod-coil IL cation that yields self-assembled mesophases in which the formation of tetragonal morphologies is favored. Covalent linking of the IL cations by UV-induced polymerization converts the lyotropic mesophase into three-dimensional biocontinuous chemical gels. Reducing the alkyl chain length, as in the polymerizable IL cation 1-(8-(acryloyloxy)octyl)-3-methylimidazolium chloride, severely reduces the self-assembled mesophase order, and triggers the formation of only weakly ordered one-dimensional lamellar structures.

  13. Swelling and shrinking properties of thermo-responsive polymeric ionic liquid hydrogels with embedded linear pNIPAAM.

    PubMed

    Gallagher, Simon; Florea, Larisa; Fraser, Kevin J; Diamond, Dermot

    2014-01-01

    In this study, varying concentrations of linear pNIPAAM have been incorporated for the first time into a thermo-responsive polymeric ionic liquid (PIL) hydrogel, namely tributyl-hexyl phosphonium 3-sulfopropylacrylate (P-SPA), to produce semi-interpenetrating polymer networks. The thermal properties of the resulting hydrogels have been investigated along with their thermo-induced shrinking and reswelling capabilities. The semi-interpenetrating networks (IPN) hydrogels were found to have improved shrinking and reswelling properties compared with their PIL counterpart. At elevated temperatures (50-80 °C), it was found that the semi-IPN with the highest concentration of hydrophobic pNIPAAM exhibited the highest shrinking percentage of ~40% compared to the conventional P-SPA, (27%). This trend was also found to occur for the reswelling measurements, with semi-IPN hydrogels producing the highest reswelling percentage of ~67%, with respect to its contracted state. This was attributed to an increase in water affinity due to the presence of hydrophilic pNIPAAM. Moreover, the presence of linear pNIPAAM in the polymer matrix leads to improved shrinking and reswelling response compared to the equivalent PIL.

  14. Electrospun Pd nanoparticles loaded on Vulcan carbon/ conductive polymeric ionic liquid nanofibers for selective and sensitive determination of tramadol.

    PubMed

    Fathirad, Fariba; Mostafavi, Ali; Afzali, Daryoush

    2016-10-12

    In the present work a sensitive and selective electrochemical sensor was fabricated based on a glassy carbon electrode which has been modified with Pd nanoparticles loaded on Vulcan carbon/conductive polymeric ionic liquid composite nanofibers. The nanostructures were characterized by UV-Vis, FT-IR, FESEM, EDX and XRD techniques. The electrochemical study of the modified electrode, as well as its efficiency for the electrooxidation of tramadol was described in 0.1 M phosphate buffered solution (PBS) (pH 7.0) using cyclic voltammetry, linear sweep voltammetry, chronoamperometry and square wave voltammetry as diagnostic techniques. It has been found that application of the composite nanofibers result in a sensitivity enhancement and a considerable decrease in the anodic overpotential, leading to negative shifts about 200 mV in peak potential. The results exhibit a linear dynamic range from 0.05 μM to 200 μM and a detection limit of 0.015 μM for tramadol. Finally, the modified electrode was used for the determination of tramadol in pharmaceutical and biological samples. PMID:27662760

  15. Electroactive polymeric sensors in hand prostheses: bending response of an ionic polymer metal composite.

    PubMed

    Biddiss, Elaine; Chau, Tom

    2006-07-01

    In stark contrast to the inspiring functionality of the natural hand, limitations of current upper limb prostheses stemming from marginal feedback control, challenges of mechanical design, and lack of sensory capacity, are well-established. This paper provides a critical review of current sensory systems and the potential of a selection of electroactive polymers for sensory applications in hand prostheses. Candidate electroactive polymers are reviewed in terms of their relevant advantages and disadvantages, together with their current implementation in related applications. Empirical analysis of one of the most novel electroactive polymers, ionic polymer metal composites (IPMC), was conducted to demonstrate its potential for prosthetic applications. With linear responses within the operating range typical of hand prostheses, bending angles, and bending rates were accurately measured with 4.4+/-2.5 and 4.8+/-3.5% error, respectively, using the IPMC sensors. With these comparable error rates to traditional resistive bend sensors and a wide range of sensitivities and responses, electroactive polymers offer a promising alternative to more traditional sensory approaches. Their potential role in prosthetics is further heightened by their flexible and formable structure, and their ability to act as both sensors and actuators. PMID:16260170

  16. A two-component polymeric optode membrane based on a multifunctional ionic liquid.

    PubMed

    Kavanagh, Andrew; Byrne, Robert; Diamond, Dermot; Radu, Aleksandar

    2011-01-21

    This work details the use of a 2-component optode membrane which is capable of generating three distinct colours in the presence of Cu(2+) and Co(2+) ions. It has been found that the ionic liquid (IL) trihexyltetradecylphosphonium dicyanamide [P(6,6,6,14)][DCA] can act as plasticizer, ligand and transducer dye when used in poly(vinyl chloride) (PVC) membranes, which significantly simplifies the optode membrane cocktail. Upon exposure to an aqueous Cu(2+) solution, a yellow colour is generated within the membrane, while exposure to an aqueous Co(2+) solution generates a blue colour. Exposure to a solution containing both ions produces a green colour. Vibrational spectroscopy has been used to investigate the molecular basis of the IL-metal ion the binding mechanism. Analytical characteristics of the membranes including the effect of interfering ions, binding constants and the limit of detection for both ions have been estimated. Finally the case of simultaneous dual-analyte recognition is presented based on two distinct absorption maxima.

  17. Separation of proteins by cation-exchange sequential injection chromatography using a polymeric monolithic column.

    PubMed

    Masini, Jorge Cesar

    2016-02-01

    Since sequential injection chromatography (SIC) emerged in 2003, it has been used for separation of small molecules in diverse samples, but separations of high molar mass compounds such as proteins have not yet been described. In the present work a poly(glycidyl methacrylate-co-ethylene dimethacrylate) (GMA-co-EDMA) monolithic column was prepared by free radical polymerization inside a 2.1-mm-i.d. activated fused silica-lined stainless steel tubing and modified with iminodiacetic acid (IDA). The column was prepared from a mixture of 24% GMA, 16% EDMA, 20% cyclohexanol, and 40% 1-dodecanol (all% as w/w) containing 1% of azobisisobutyronitrile (AIBN) (in relation to monomers). Polymerization was done at 60 °C for 24 h. The polymer was modified with 1.0 M IDA (in 2 M Na2CO3, pH 10.5) at 80 °C for 16 h. Separation of myoglobin, ribonuclease A, cytochrome C, and lysozyme was achieved at pH 7.0 (20 mM KH2PO4/K2HPO4) using a salt gradient (NaCl). Myoglobin was not retained, and the other proteins were separated by a gradient of NaCl created inside the holding coil (4 m of 0.8-mm-i.d. PTFE tubing) by sequential aspiration of 750 and 700 μL of 0.2 and 0.1 M NaCl, respectively. As the flow was reversed toward the column (5 μL s(-1)) the interdispersion of these solutions created a reproducible gradient which separated the proteins in 10 min, with the following order of retention: ribonuclease A < cytochrome C < lysozyme. The elution order was consistent with a cation-exchange mechanism as the retention increased with the isoelectric points.

  18. Preparation of stir cake sorptive extraction based on polymeric ionic liquid for the enrichment of benzimidazole anthelmintics in water, honey and milk samples.

    PubMed

    Wang, Yulei; Zhang, Jie; Huang, Xiaojia; Yuan, Dongxing

    2014-08-20

    In this work, a new stir cake sorptive extraction (SCSE) using polymeric ionic liquid monolith as sorbent was prepared. The sorbent was obtained by in situ copolymerization of an ionic liquid, 1-allyl-3-methylimidazolium bis[(trifluoro methyl)sulfonyl]imide (AMII) and divinylbenzene (DB) in the presence of N,N-dimethylformamide. The influence of the content of ionic liquid and the porogen in the polymerization mixture on extraction performance was studied thoroughly. The physicochemical properties of the polymeric ionic liquid were characterized by infrared spectroscopy, elemental analysis, scanning electron microscopy and mercury intrusion porosimetry. The usefulness of SCSE-AMIIDB was demonstrated by the enrichment of trace benzimidazole anthelmintics. Several parameters affecting the extraction efficiency were investigated, and under the optimized conditions, a simple and effective method for the determination of trace benzimidazoles residues in water, milk and honey samples was established by coupling SCSE-AMIIDB with high performance liquid chromatography/diode array detection (SCSE-AMIIDB-HPLC/DAD). Results indicated that the limits of detection (S/N=3) for target compounds were 0.020-0.072 μg L(-1), 0.035-0.10 μg L(-1) and 0.026-0.076 μg L(-1) in water, milk and honey samples, respectively. In addition, an acceptable reproducibility was achieved by evaluating the repeatability and intermediate precision with relative standard deviations (RSD) of less than 9% and 11%, respectively. Finally, the established AMII-SCSE-HPLC/DAD method was successfully applied for the determination of benzimidazoles residues in milk, honey and environmental water samples. Recoveries obtained for the determination of benzimidazole anthelmintics in spiking samples ranged from 70.2% to 117.6%, with RSD below 12% in all cases.

  19. Hydroxyl-Exchanged Nanoporous Ionic Copolymer toward Low-Temperature Cycloaddition of Atmospheric Carbon Dioxide into Carbonates.

    PubMed

    Guo, Zengjing; Cai, Xiaochun; Xie, Jingyan; Wang, Xiaochen; Zhou, Yu; Wang, Jun

    2016-05-25

    An ionic copolymer catalyst with nanopores, large surface area, high ionic density, and superior basicity was prepared via the radical copolymerization of amino-functionalized ionic liquid bromide and divinylbenzene, followed with a hydroxyl exchange for removing bromonium. Evaluated in chemical fixation of CO2 with epoxides into cyclic carbonates in the absence of any solvent and basic additive, the nanoporous copolymer catalyst showed high and stable activity, superior to various control catalysts including the halogen-containing analogue. Further, high yields were obtained over a wide scope of substrates including aliphatic long carbon-chain alkyl epoxides and internal epoxide, even under atmospheric pressure and less than 100 °C for the majority of the substrates. On the basis of in situ Fourier transform infrared (FT-IR) investigation and density functional theory (DFT) calculation for the reaction intermediates, we proposed a possible reaction mechanism accounting for the superior catalytic activity of the ionic copolymer. The specifically prepared ionic copolymer material of this work features highly stable, noncorrosive, and sustainable catalysis and, thus, may be a new possibility for efficient chemical fixation of CO2 since it is an environmentally friendly, metal-free solid catalyst. PMID:27142654

  20. Study of Np(V) Sorption by Ionic Exchange on Na, K, Ca and Mg-Montmorillonite

    NASA Astrophysics Data System (ADS)

    Benedicto, A.; Begg, J.; Zhao, P.; Kersting, A. B.; Zavarin, M.

    2012-12-01

    The transport behavior of actinides in soil and ground water are highly influenced by clay minerals due to their ubiquity in the environment, reactivity and colloidal properties. Neptunium(V) has been introduced in the environment as a result of nuclear weapons testing [e.g. 1, 2] and is a radionuclide of potential interest for safety assessment of high level radioactive waste disposal because its long half-life and high toxicity [3]. Surface complexation and ionic exchange have been identified as Np(V) sorption mechanisms onto montmorillonite. At pH below 5, Np(V) sorption is mainly attributed to ionic exchange. This study examines Np(V) ion exchange on Na, K, Ca and Mg forms of montmorillonite. Experiments were carried out using 237Np concentrations between 2 x 10-8 M and 5 x 10-6 M at three different ionic strengths 0.1, 0.01 and 0.001M. The pH was maintained at 4.5. Np(V) sorption to montmorillonite homoionized with monovalent cations (Na and K) demonstrated a markedly different behavior to that observed for montmorillonite homoionized with divalent cations (Ca and Mg). Np sorption to Na and K-montmorillonite was greater than Np sorption to Ca and Mg-montmorillonite. Isotherms with Na and K-montmorillonite showed a strong dependence on ionic strength: the percentage of Np adsorbed was near zero at 0.1M ionic strength, but increased to 30% at 0.001 M ionic strength. This suggests ionic exchange is the main Np adsorption mechanism under the experimental conditions investigated. Dependence on ionic strength was not observed in the Np sorption isotherms for Ca and Mg-montmorillonite indicating a low exchange capacity between Np and divalent cations. Modeling of the sorption experimental data will allow determination of the Na+↔NpO2+ and K+↔NpO2+ ionic exchange constants on montmorillonite. References: [1] A. R. Felmy; K. J. Cantrell; S. D. Conradson, Phys. Chem. Earth 2010, 35, 292-297 [2] D. K. Smith; D. L. Finnegan; S. M. Bowen, J. Environ. Radioact. 2003, 67

  1. High ionic strength narrows the population of sites participating in protein ion-exchange adsorption: A single-molecule study

    PubMed Central

    Kisley, Lydia; Chen, Jixin; Mansur, Andrea P.; Dominguez-Medina, Sergio; Kulla, Eliona; Kang, Marci; Shuang, Bo; Kourentzi, Katerina; Poongavanam, Mohan-Vivekanandan; Dhamane, Sagar; Willson, Richard C.; Landes, Christy F.

    2014-01-01

    The retention and elution of proteins in ion-exchange chromatography is routinely controlled by adjusting the mobile phase salt concentration. It has repeatedly been observed, as judged from adsorption isotherms, that the apparent heterogeneity of adsorption is lower at more-eluting, higher ionic strength. Here, we present an investigation into the mechanism of this phenomenon using a single-molecule, super-resolution imaging technique called motion-blur Points Accumulation for Imaging in Nanoscale Topography (mbPAINT). We observed that the number of functional adsorption sites was smaller at high ionic strength and that these sites had reduced desorption kinetic heterogeneity, and thus narrower predicted elution profiles, for the anion-exchange adsorption of α-lactalbumin on an agarose-supported, clustered-charge ligand stationary phase. Explanations for the narrowing of the functional population such as inter-protein interactions and protein or support structural changes were investigated through kinetic analysis, circular dichroism spectroscopy, and microscopy of agarose microbeads, respectively. The results suggest the reduction of heterogeneity is due to both electrostatic screening between the protein and ligand and tuning the steric availability within the agarose support. Overall, we have shown that single molecule spectroscopy can aid in understanding the influence of ionic strength on the population of functional adsorbent sites participating in the ion-exchange chromatographic separation of proteins. PMID:24751557

  2. In-situ graft-polymerization preparation of cation-exchange supermacroporous cryogel with sulfo groups in glass columns.

    PubMed

    Yao, Kejian; Yun, Junxian; Shen, Shaochuan; Chen, Fang

    2007-07-20

    Graft polymerization of monomer chains with expected functional groups onto the matrix pore surfaces by initiator is an effective approach for introducing ion-exchange groups to cryogel matrix to get anion- or cation-exchange supermacroporous cryogels. In this work, a novel cation-exchange cryogel with sulfo binding groups was prepared by grafting of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPSA) onto polyacrylamide-based cryogels in glass columns. The grafting polymerization was achieved in an in-situ manner which was performed by pumping the initiator and the reactive solution of graft monomer with sulfo binding groups directly through a cryogel bed pre-produced in a glass column under frozen condition. The axial liquid dispersion characteristics within the monolithic cryogel beds before and after the in-situ polymerization were compared by measuring residence time distributions (RTDs) at various liquid flow rates using tracer pulse-response method. Microstructure morphology of pores within cryogels was analyzed by scanning electron microscopy (SEM). Chromatography of lysozyme was carried out to reveal the protein breakthrough and elution characteristics in the obtained cryogel beds.

  3. In-situ graft-polymerization preparation of cation-exchange supermacroporous cryogel with sulfo groups in glass columns.

    PubMed

    Yao, Kejian; Yun, Junxian; Shen, Shaochuan; Chen, Fang

    2007-07-20

    Graft polymerization of monomer chains with expected functional groups onto the matrix pore surfaces by initiator is an effective approach for introducing ion-exchange groups to cryogel matrix to get anion- or cation-exchange supermacroporous cryogels. In this work, a novel cation-exchange cryogel with sulfo binding groups was prepared by grafting of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPSA) onto polyacrylamide-based cryogels in glass columns. The grafting polymerization was achieved in an in-situ manner which was performed by pumping the initiator and the reactive solution of graft monomer with sulfo binding groups directly through a cryogel bed pre-produced in a glass column under frozen condition. The axial liquid dispersion characteristics within the monolithic cryogel beds before and after the in-situ polymerization were compared by measuring residence time distributions (RTDs) at various liquid flow rates using tracer pulse-response method. Microstructure morphology of pores within cryogels was analyzed by scanning electron microscopy (SEM). Chromatography of lysozyme was carried out to reveal the protein breakthrough and elution characteristics in the obtained cryogel beds. PMID:17517417

  4. Single ion conducting, polymerized ionic liquid triblock copolymer films: high capacitance electrolyte gates for n-type transistors.

    PubMed

    Choi, Jae-Hong; Xie, Wei; Gu, Yuanyan; Frisbie, C Daniel; Lodge, Timothy P

    2015-04-01

    There has been impressive progress in the fabrication and characterization of p-type organic electrolyte-gated transistors (EGTs). Unfortunately, despite the importance of n-type organic transistors for complementary circuits, fewer investigations have focused on developing electrolytes as gate dielectrics for n-type organic semiconductors. Here, we present a novel single ion conductor, a polymerized ionic liquid (PIL) triblock copolymer (PS-PIL-PS) composed of styrene (PS) and 1-[(2-acryloyloxy)ethyl]-3-butylimidazolium bis(trifluoromethylsulfonyl)imide (PIL), that conducts only the TFSI anion. This triblock copolymer acts as a gate dielectric to allow low-voltage n-type organic EGT operation. Impedance characterization of PS-PIL-PS reveals that there are three polarization regions: (1) dipolar relaxation, (2) ion migration, and (3) electric double layer (EDL) formation. These polarization regions are controlled by film thickness, and rapid EDL formation can be obtained in thinner polyelectrolyte films. In particular, a 500 nm-thick polyelectrolyte film exhibits a large capacitance of ∼1 μF/cm(2) at 10 kHz. Employing this single ion conducting PIL triblock copolymer as the gate insulator, we achieved low voltage operation (<1 V supply) of poly{[N,N'-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)} (P(NDI2OD-T2)) n-type organic EGTs (electron mobility of ∼0.008 cm(2)/(V·s) and ON/OFF current ratio of ∼2 × 10(3)) by preventing electrochemical doping. Furthermore, the recognition that the performance of n-type organic EGTs is diminished by 3D electrochemical doping suggests that it may be necessary to have a unipolar electrolyte to gate n-type organic semiconductors. Finally, we highlight that the use of PIL block copolymer electrolytes as gate insulators opens unique opportunities to explore the role of ion penetration in n-type organic EGTs by tuning the extent of electrochemical doping.

  5. Click Chemistry Finds Its Way in Constructing an Ionic Highway in Anion-Exchange Membrane.

    PubMed

    Ge, Qianqian; Ran, Jin; Miao, Jibin; Yang, Zhengjin; Xu, Tongwen

    2015-12-30

    To find the way to construct an ionic highway in anion-exchange membranes (AEMs), a series of side-chain-type alkaline polymer electrolytes (APEs) based on poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) polymer backbones were synthesized via Cu(I)-catalyzed click chemistry. The resulting triazole groups and quaternary ammonium (QA) groups facilitate the formation of a continuous hydrogen bond network, which will lead to high hydroxide conductivity according to Grotthuss-type mechanism. Microphase separation induced by long alkyl side chains contributes at the same time to further improving the hydroxide conductivity of the resultant AEMs. Hydroxide conductivity as high as 52.8 mS/cm is obtained for membrane TA-14C-1.21 (IEC = 1.21 mmol/g) with the longest pendant chain at 30 °C, and the conductivity can be increased to 140 mS/cm when the temperature was increased to 80 °C. Moreover, the corresponding water uptake is only 8.6 wt % at 30 °C. In the meantime, the membrane properties can be tuned by precisely regulating the hydrophilic/hydrophobic ratio in the cationic head groups. Compared with AEMs containing triazole and quaternized trimethylammonium head groups, enhanced dimensional stability and mechanical properties are obtained by tuning side-chain chemistry. However, the alkaline stability of the membrane is not as stable as anticipated, probably because of the existence of the triazole ring. Further study will be focused on increasing the alkali stability of the membrane. We envisage that the side-chain-type APEs meditated by click chemistry bearing long hydrophobic side chains pendant to the cationic head groups hold promise as a novel AEMs material. PMID:26645427

  6. Atmospheric Ionic Deposition in Tropical Sites of Central Sulawesi Determined by Ion Exchange Resin Collectors and Bulk Water Collector.

    PubMed

    Köhler, S; Jungkunst, H F; Gutzler, C; Herrera, R; Gerold, G

    2012-09-01

    In the light of global change, the necessity to monitor atmospheric depositions that have relevant effects on ecosystems is ever increasing particularly for tropical sites. For this study, atmospheric ionic depositions were measured on tropical Central Sulawesi at remote sites with both a conventional bulk water collector system (BWS collector) and with a passive ion exchange resin collector system (IER collector). The principle of IER collector to fix all ionic depositions, i.e. anions and cations, has certain advantages referring to (1) post-deposition transformation processes, (2) low ionic concentrations and (3) low rainfall and associated particulate inputs, e.g. dust or sand. The ionic concentrations to be measured for BWS collectors may easily fall below detection limits under low deposition conditions which are common for tropical sites of low land use intensity. Additionally, BWS collections are not as independent from the amount of rain fallen as are IER collections. For this study, the significant differences between both collectors found for nearly all measured elements were partly correlated to the rainfall pattern, i.e. for calcium, magnesium, potassium and sodium. However, the significant differences were, in most cases, not highly relevant. More relevant differences between the systems were found for aluminium and nitrate (434-484 %). Almost five times higher values for nitrate clarified the advantage of the IER system particularly for low deposition rate which is one particularity of atmospheric ionic deposition in tropical sites of extensive land use. The monthly resolution of the IER data offers new insights into the temporal distribution of annual ionic depositions. Here, it did not follow the tropical rain pattern of a drier season within generally wet conditions.

  7. The configuration exchanging theory for transport properties and glass formation temperature of ionic liquids.

    PubMed

    Hu, Yu-Feng; Zhang, Xian-Ming; Qi, Jian-Guang; Yin, Liu-Yi

    2015-11-28

    Understanding molecular motion in terms of molecular structure is an important issue for microscopic understanding of the nature of transport properties and glass transition, and for design of structured materials to meet specific demands in various applications. Herein, a novel molecular mechanism is proposed to connect macroscopic motion in ionic liquids with molecular structure via conformational conversions of the constituent ions or of the cation-anion pairs. New equations for description of relaxation time, diffusion coefficient, molar conductivity, and viscosity of ionic liquids are established. The equation parameters, which were determined from the temperature dependent heat capacities, self-diffusion coefficients, molar conductivities, and viscosities of typical ionic liquids, were used to produce predictions for the corresponding properties of other ionic liquids and for the glass transition temperatures of representative ionic liquids. All predictions are in nice agreements with the experimental results.

  8. Molecularly imprinted electrochemical sensing interface based on in-situ-polymerization of amino-functionalized ionic liquid for specific recognition of bovine serum albumin.

    PubMed

    Wang, Yanying; Han, Miao; Liu, Guishen; Hou, Xiaodong; Huang, Yina; Wu, Kangbing; Li, Chunya

    2015-12-15

    A molecularly imprinted polymer film was in situ polymerized on a carboxyl functionalized multi-walled carbon nanotubes modified glassy carbon electrode surface under room temperature. This technique provides a promising imprinting approach for protein in an aqueous solution using 3-(3-aminopropyl)-1-vinylimidazolium tetrafluoroborate ionic liquid as functional monomer, N, N'-methylenebisacrylamide as crossing linker, ammonium persulfate and N,N,N',N'-tetramethylethylenediamine as initiator, and bovine serum albumin (BSA) as template. The molecularly imprinted polymerized ionic liquid film shows enhanced accessibility, high specificity and sensitivity towards BSA. Electrochemical sensing performance of the imprinted sensor was thoroughly investigated using K3Fe[CN]6/K4Fe[CN]6 as electroactive probes. Under optimal conditions, the current difference before and after specific recognition of BSA was found linearly related to its concentration in the range from 1.50×10(-9) to 1.50×10(-6) mol L(-1). The detection limit was calculated to be 3.91×10(-10) mol L(-1) (S/N=3). The practical application of the imprinted sensor was demonstrated by determining BSA in liquid milk samples. PMID:26232004

  9. 3D interconnected ionic nano-channels formed in polymer films: self-organization and polymerization of thermotropic bicontinuous cubic liquid crystals.

    PubMed

    Ichikawa, Takahiro; Yoshio, Masafumi; Hamasaki, Atsushi; Kagimoto, Junko; Ohno, Hiroyuki; Kato, Takashi

    2011-02-23

    Thermotropic bicontinuous cubic (Cub(bi)) liquid-crystalline (LC) compounds based on a polymerizable ammonium moiety complexed with a lithium salt have been designed to obtain lithium ion-conductive all solid polymeric films having 3D interconnected ionic channels. The monomer shows a Cub(bi) phase from -5 to 19 °C on heating. The complexes retain the ability to form the Cub(bi) LC phase. They also form hexagonal columnar (Col(h)) LC phases at temperatures higher than those of the Cub(bi) phases. The complex of the monomer and LiBF(4) at the molar ratio of 4:1 exhibits the Cub(bi) and Col(h) phases between -6 to 19 °C and 19 to 56 °C, respectively, on heating. The Cub(bi) LC structure formed by the complex has been successfully preserved by in situ photopolymerization through UV irradiation in the presence of a photoinitiator. The resultant nanostructured film is optically transparent and free-standing. The X-ray analysis of the film confirms the preservation of the self-assembled nanostructure. The polymer film with the Cub(bi) LC nanostructure exhibits higher ionic conductivities than the polymer films obtained by photopolymerization of the complex in the Col(h) and isotropic phases. It is found that the 3D interconnected ionic channels derived from the Cub(bi) phase function as efficient ion-conductive pathways.

  10. Effect of the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) upon membrane ionic exchanges in sea urchin eggs

    SciTech Connect

    Ciapa, B.; Payan, P. ); Allemand, D. )

    1989-12-01

    The effect of TPA (12-O-tetradecanoylphorbol-13-acetate) upon ionic exchanges was investigated in eggs of the sea urchin Arbacia lixula. Ouabain-sensitive {sup 86}Rb uptake and amiloride-sensitive {sup 24}Na influx were dramatically stimulated after TPA addition, indicating an enhancement of total ionic permeabilities. Stimulation by TPA of both Na{sup +}/H{sup +} and Na{sup +}/K{sup +} exchanges was canceled by amiloride, suggesting that activation of protein kinase C elicits, via Na{sup +}/H{sup +} activity, stimulation of the sodium pump. However, TPA did not stimulate sodium pump activity and Na{sup +}/H{sup +} exchange at the same rate as fertilization, probably because of an absence of calcium-dependent events. Further fertilization of TPA pretreated eggs triggered an enhancement of sodium pump activity when the TPA treatment duration did not exceed 10 minutes. It is suggested that TPA activates preexisting transporting mechanisms in plasma membranes of unfertilized eggs (Na{sup +} stat, pH stat).

  11. Effect of ionic strength on ligand exchange kinetics between a mononuclear ferric citrate complex and siderophore desferrioxamine B

    NASA Astrophysics Data System (ADS)

    Ito, Hiroaki; Fujii, Manabu; Masago, Yoshifumi; Waite, T. David; Omura, Tatsuo

    2015-04-01

    The effect of ionic strength (I) on the ligand exchange reaction between a mononuclear ferric citrate complex and the siderophore, desferrioxamine B (DFB), was examined in the NaCl concentration range of 0.01-0.5 M, particularly focusing on the kinetics and mechanism of ligand exchange under environmentally relevant conditions. Overall ligand exchange rate constants were determined by spectrophotometrically measuring the time course of ferrioxamine B formation at a water temperature of 25 °C, pH 8.0, and citrate/Fe molar ratios of 500-5000. The overall ligand exchange rate decreased by 2-11-fold (depending on the citrate/Fe molar ratios) as I increased from approximately 0.01 to 0.5 M. In particular, a relatively large decrease was observed at lower I (<0.1 M). A ligand exchange model describing the effect of I on the ligand exchange rate via disjunctive and adjunctive pathways was developed by considering the pseudo-equilibration of ferric citrate complexes and subsequent ferrioxamine formation on the basis of the Eigen-Wilkins metal-ligand complexation theory. The model and experimental data consistently suggest that the adjunctive pathway (i.e., direct association of DFB with ferric mono- and di-citrate complexes following dissociation of citrate from the parent complexes) dominates in ferrioxamine formation under the experimental conditions used. The model also predicts that the higher rate of ligand exchange at lower I is associated with the decrease in the ferric dicitrate complex stability because of the relatively high electrical repulsion between ferric monocitrate and free citrate at lower I (note that the reactivity of ferric dicitrate with DFB is smaller than that for the monocitrate complex). Overall, the findings of this study contribute to the understanding of the potential effect of I on ligand exchange kinetics in natural waters and provide fundamental knowledge on iron transformation and bioavailability.

  12. Preparation of Cation-Exchange Particle Designed for High-Speed Collection of Proteins by Radiation-Induced Graft Polymerization

    NASA Astrophysics Data System (ADS)

    Sekiya, Yuta; Shimoda, Yuichi; Umeno, Daisuke; Saito, Kyoichi; Furumoto, Goro; Shirataki, Hironobu; Shinohara, Naoyuki; Kubota, Noboru

    A cation-exchange polymer brush was immobilized onto a polyethylene-based particle with an average diameter of 35 μm by radiation-induced graft polymerization of glycidyl methacrylate and subsequent sulfonation with sodium sulfite. A lysozyme solution was forced to flow through a bed (height 2 cm, cross-sectional area 0.61 cm2) charged with the resultant cation-exchange particles at a space velocity ranging from 500 to 2300 h-1. From a viewpoint of equilibrium binding capacity and elution percentage of lysozyme, the dose of electron beam and the degree of GMA grafting were optimized to be 200 kGy and 100%, respectively. The bed exhibited a constant dynamic binding capacity of lysozyme 14 mg⁄mL irrespective of space velocity due to negligible diffusional mass-transfer resistance.

  13. Diacetylenes with Ionic-Liquid-Like Substituents: Associating a Polymerizing Cation with a Polymerizing Anion in a Single Precursor for the Synthesis of N-Doped Carbon Materials.

    PubMed

    Fahsi, Karim; Dumail, Xavier; Dutremez, Sylvain G; van der Lee, Arie; Vioux, André; Viau, Lydie

    2016-01-26

    Imidazolium- and benzimidazolium-substituted diacetylenes with bromide or nitrogen-rich dicyanamide and tricyanomethanide anions were synthesized and used as precursors for the preparation of N-doped carbon materials. On pyrolysis under argon at 800 °C both halide precursors afforded graphite-like structures with nitrogen contents of about 8.5%. When the dicyanamide and tricyanomethanide precursors were thermolyzed at the same temperature, graphite-like structures were obtained that exhibit nitrogen contents in the range 17-20 wt%; thereby, the benefit of associating a polymerizing cation with a polymerizing anion in a single precursor was demonstrated. On pyrolysis at 1100 °C the nitrogen contents of the latter pyrolysates remain high (ca. 6 wt%). Adsorption measurements with krypton at 77 K indicated that the materials are nonporous. The highest electrical conductivity was observed for a pyrolysate with one of the lowest nitrogen contents, which also has the highest degree of graphitization. Thus, the quest for N-rich carbons with high electrical conductivities should include both maximization of the nitrogen content and optimization of the degree of graphitization. Crystallographic investigation of the precursors and spectroscopic characterization of the pyrolysates prepared by heating at 220 °C indicate that construction of the final carbon framework does not involve the intermediate formation of a polydiacetylene. PMID:26695842

  14. Synthesis and performance of novel anion exchange membranes based on imidazolium ionic liquids for alkaline fuel cell applications

    NASA Astrophysics Data System (ADS)

    Fang, Jun; Lyu, Ming; Wang, Xin; Wu, Yongbin; Zhao, Jinbao

    2015-06-01

    Novel anion exchange membranes (AEMs) based on two types of imidazolium ionic liquids, 1-vinyl-3-methylimidazolium iodide [VMI]I and 1-vinyl-3-butylimidazolium bromide [VBI]Br, have been synthesized by copolymerization. The obtained membranes are characterized in terms of water uptake, ion exchange capacity (IEC), ionic conductivity as well as thermal and chemical stability. The conductivity reaches 0.0226 Scm-1 at 30 °C. All the membranes show excellent thermostability. The membranes are stable in 10 mol L-1 NaOH solution at 60 °C for 120 h without obvious changes in ion conductivity. Fuel cell performance using the resulting membrane has been investigated. The open circuit voltage (OCV) of the H2/O2 fuel cell is 1.07 V. A peek power density of 116 mW cm-2 is obtained at a current density of 230 mA cm-2 at 60 °C. The results demonstrate the brilliant prospect of the developed membranes for alkaline fuel cell applications.

  15. Selective extraction of metal ions with polymeric extractants by ion exchange/redox

    DOEpatents

    Alexandratos, Spiro D.

    1987-01-01

    The specification discloses a method for the extraction of metal ions having a reduction potential of above about +0.3 from an aqueous solution. The method includes contacting the aqueous solution with a polymeric extractant having primary phosphinic acid groups, secondary phosphine oxide groups, or both phosphinic acid and phosphine oxide groups.

  16. Fabrication of an ionic liquid-based macroporous polymer monolithic column via atom transfer radical polymerization for the separation of small molecules.

    PubMed

    Zhang, Hang; Bai, Ligai; Wei, Zhen; Liu, Sha; Liu, Haiyan; Yan, Hongyuan

    2016-03-01

    A polymer monolithic column was prepared in a stainless steel column (50×4.6mm i.d.) via atom transfer radical polymerization technique using triallyl isocyanurate and ionic liquid (1-allyl-3-methylimidazolium chloride) as co-monomers, ethylene dimethacrylate as cross linking agent, polyethylene glycol 200, 1,4-butanediol, and N, N- dimethylformamide as porogen system, CCl4 as initiator, and FeCl2 as catalyst. The optimized polymer columns were characterized by scanning electron microscope, nitrogen adsorption-desorption instrument, mercury intrusion porosimetry, infrared spectrometer, and thermogravimetric analysis technique. Respectively, all of these factors above could illustrate that the optimized columns had relative uniform macroporous structure and high thermal stability. A series of basic and acidic small molecules, isomers, and homologues were used to evaluate the performance of these monoliths and enhanced column efficiency was obtained. PMID:26717814

  17. Preparation of a polymeric ionic liquid-based adsorbent for stir cake sorptive extraction of preservatives in orange juices and tea drinks.

    PubMed

    Chen, Lei; Huang, Xiaojia

    2016-04-15

    In this study, a new polymeric ionic liquid-based adsorbent was prepared and used as the extraction medium of stir cake sorptive extraction (SCSE) of three organic acid preservatives, namely, p-hydroxybenzoic acid, sorbic acid and cinnamic acid. The adsorbent was synthesized by the copolymerization of 1-ally-3-vinylimidazolium chloride (AV) and divinylbenzene (DVB) in the presence of a porogen solvent containing 1-propanol and 1,4-butanediol. The effect of the content of monomer and the porogen solvent in the polymerization mixture on the extraction performance was investigated thoroughly. The adsorbent was characterized by infrared spectroscopy, elemental analysis, scanning electron microscopy and mercury intrusion porosimetry. To obtain the optimal extraction conditions of SCSE/AVDVB for target analytes, key parameters including desorption solvent, adsorption and desorption time, ionic strength and pH value in sample matrix were studied in detail. The results showed that under the optimized conditions, the SCSE/AVDVB could extract the preservatives effectively through multiply interactions. At the same time, a simple and sensitive method by combining SCSE/AVDVB and high-performance liquid chromatography with diode array detection was developed for the simultaneous analysis of the target preservatives in orange juices and tea drinks. Low limits of detection (S/N = 3) and quantification limits (S/N = 10) of the proposed method for the target analytes were achieved within the range of 0.012-0.23 μg/L and 0.039-0.42 μg/L, respectively. The precision of the proposed method was evaluated in terms of intra- and inter-assay variability calculated as relative standard deviation (RSD), and it was found that the values were all below 10%. Finally, the proposed method was used to detect preservatives in different orange juice and tea drink samples successfully. The recoveries were in the range of 71.9-116%, and the RSDs were below 10% in the all cases.

  18. Crosslinked structurally-tuned polymeric ionic liquids as stationary phases for the analysis of hydrocarbons in kerosene and diesel fuels by comprehensive two-dimensional gas chromatography.

    PubMed

    Zhang, Cheng; Park, Rodney A; Anderson, Jared L

    2016-04-01

    Structurally-tuned ionic liquids (ILs) have been previously applied as the second dimension column in comprehensive two-dimensional gas chromatography (GC×GC) and have demonstrated high selectivity in the separation of individual aliphatic hydrocarbons from other aliphatic hydrocarbons. However, the maximum operating temperatures of these stationary phases limit the separation of analytes with high boiling points. In order to address this issue, a series of polymeric ionic liquid (PIL)-based stationary phases were prepared in this study using imidazolium-based IL monomers via in-column free radical polymerization. The IL monomers were functionalized with long alkyl chain substituents to provide the needed selectivity for the separation of aliphatic hydrocarbons. Columns were prepared with different film thicknesses to identify the best performing stationary phase for the separation of kerosene. The bis[(trifluoromethyl)sulfonyl]imide ([NTf2](-))-based PIL stationary phase with larger film thickness (0.28μm) exhibited higher selectivity for aliphatic hydrocarbons and showed a maximum allowable operating temperature of 300°C. PIL-based stationary phases containing varied amount of IL-based crosslinker were prepared to study the effect of the crosslinker on the selectivity and thermal stability of the resulting stationary phase. The optimal resolution of aliphatic hydrocarbons was achieved when 50% (w/w) of crosslinker was incorporated into the PIL-based stationary phase. The resulting stationary phase exhibited good selectivity for different groups of aliphatic hydrocarbons even after being conditioned at 325°C. Finally, the crosslinked PIL-based stationary phase was compared with SUPELCOWAX 10 and DB-17 columns for the separation of aliphatic hydrocarbons in diesel fuel. Better resolution of aliphatic hydrocarbons was obtained when employing the crosslinked PIL-based stationary phase as the second dimension column. PMID:26916595

  19. Crosslinked structurally-tuned polymeric ionic liquids as stationary phases for the analysis of hydrocarbons in kerosene and diesel fuels by comprehensive two-dimensional gas chromatography.

    PubMed

    Zhang, Cheng; Park, Rodney A; Anderson, Jared L

    2016-04-01

    Structurally-tuned ionic liquids (ILs) have been previously applied as the second dimension column in comprehensive two-dimensional gas chromatography (GC×GC) and have demonstrated high selectivity in the separation of individual aliphatic hydrocarbons from other aliphatic hydrocarbons. However, the maximum operating temperatures of these stationary phases limit the separation of analytes with high boiling points. In order to address this issue, a series of polymeric ionic liquid (PIL)-based stationary phases were prepared in this study using imidazolium-based IL monomers via in-column free radical polymerization. The IL monomers were functionalized with long alkyl chain substituents to provide the needed selectivity for the separation of aliphatic hydrocarbons. Columns were prepared with different film thicknesses to identify the best performing stationary phase for the separation of kerosene. The bis[(trifluoromethyl)sulfonyl]imide ([NTf2](-))-based PIL stationary phase with larger film thickness (0.28μm) exhibited higher selectivity for aliphatic hydrocarbons and showed a maximum allowable operating temperature of 300°C. PIL-based stationary phases containing varied amount of IL-based crosslinker were prepared to study the effect of the crosslinker on the selectivity and thermal stability of the resulting stationary phase. The optimal resolution of aliphatic hydrocarbons was achieved when 50% (w/w) of crosslinker was incorporated into the PIL-based stationary phase. The resulting stationary phase exhibited good selectivity for different groups of aliphatic hydrocarbons even after being conditioned at 325°C. Finally, the crosslinked PIL-based stationary phase was compared with SUPELCOWAX 10 and DB-17 columns for the separation of aliphatic hydrocarbons in diesel fuel. Better resolution of aliphatic hydrocarbons was obtained when employing the crosslinked PIL-based stationary phase as the second dimension column.

  20. Synthesis of Highly Polymerized Water-soluble Cellulose Acetate by the Side Reaction in Carboxylate Ionic Liquid 1-ethyl-3-methylimidazolium Acetate.

    PubMed

    Pang, Jinhui; Liu, Xin; Yang, Jun; Lu, Fachuang; Wang, Bo; Xu, Feng; Ma, Mingguo; Zhang, Xueming

    2016-01-01

    In the present study, we describe a novel one-step method to prepare water-soluble cellulose acetate (WSCA) with higher degree of polymerization values (DP = 650-680) by in situ activation of carboxyl group in ionic liquid. First of all, cellulose was dissolved in 1-ethyl-3-methylimidazolium acetate (EmimAc) and reacted with dichloroacetyl chloride (Cl2AcCl) in order to make cellulose dichloroacetate. Under various conditions, a series of water soluble products were produced. Elemental analysis and NMR results confirmed that they were cellulose acetate with DS (degree of substitution) values in the range from 0.30 to 0.63. NMR studies demonstrated that Cl2AcCl reacted with acetate anion of EmimAc producing a mixed anhydride that acetylated cellulose. Other acylating reagents such as benzoyl chloride, chloroacetyl chloride can also work similarly. 2D NMR characterization suggested that 6-mono-O-acetyl moiety, 3,6-di-O-acetylcellulose and 2,6-di-O-acetyl cellulose were all synthesized and the reactivity of hydroxyl groups in anhydro-glucose units was in the order C-6>C-3>C-2. This work provides an alternative way to make WSCA, meanwhile, also services as a reminder that the activity of EmimAc toward carbohydrate as acylating reagents could be a problem, because the expected acylated products may not be resulted and recycling of this ionic liquid could also be difficult. PMID:27644545

  1. Development of a functionalized polymeric ionic liquid monolith for solid-phase microextraction of polar endocrine disrupting chemicals in aqueous samples coupled to high-performance liquid chromatography.

    PubMed

    Feng, Juanjuan; Sun, Min; Bu, Yanan; Luo, Chuannan

    2015-09-01

    Ionic liquids (ILs) have been efficiently used as a "designer sorbent" in sample preparation. A novel 1-(3-aminopropyl)-3-(4-vinylbenzyl)imidazolium 4-styrenesulfonate IL monomer was synthesized and copolymerized with 1,6-di(3-vinylimidazolium) hexane bishexafluorophosphate IL as cross-linking agent to prepare a cross-linked polymeric ionic liquids (PILs) monolith. Coupled to high-performance liquid chromatography (HPLC), the PILs monolith was used as a solid-phase microextraction (SPME) sorbent to extract some polar endocrine disrupting chemical (EDCs) such as estrogens, bisphenol A, and phthalate esters in aqueous samples. Preparation and extraction conditions were investigated and optimized to obtain satisfactory extraction efficiency. Limits of detection (LODs) of the proposed method for three steroid estrogens and bisphenol A were 0.25 and 0.2 μg L(-1), respectively, which were lower than or comparable to some other sample preparation methods. Intra- and inter-day repeatability for all the analytes was 2.2-12%. The monolith-to-monolith repeatability was 7.4-15%. The extraction performance of the method for analysis of target estrogens in treated domestic wastewater was investigated and compared with a dispersive liquid-liquid microextraction (DLLME) method. The proposed SPME method provided better sensitivity and higher resistance to matrix interferences.

  2. Synthesis of Highly Polymerized Water-soluble Cellulose Acetate by the Side Reaction in Carboxylate Ionic Liquid 1-ethyl-3-methylimidazolium Acetate

    PubMed Central

    Pang, Jinhui; Liu, Xin; Yang, Jun; Lu, Fachuang; Wang, Bo; Xu, Feng; Ma, Mingguo; Zhang, Xueming

    2016-01-01

    In the present study, we describe a novel one-step method to prepare water-soluble cellulose acetate (WSCA) with higher degree of polymerization values (DP = 650–680) by in situ activation of carboxyl group in ionic liquid. First of all, cellulose was dissolved in 1-ethyl-3-methylimidazolium acetate (EmimAc) and reacted with dichloroacetyl chloride (Cl2AcCl) in order to make cellulose dichloroacetate. Under various conditions, a series of water soluble products were produced. Elemental analysis and NMR results confirmed that they were cellulose acetate with DS (degree of substitution) values in the range from 0.30 to 0.63. NMR studies demonstrated that Cl2AcCl reacted with acetate anion of EmimAc producing a mixed anhydride that acetylated cellulose. Other acylating reagents such as benzoyl chloride, chloroacetyl chloride can also work similarly. 2D NMR characterization suggested that 6-mono-O-acetyl moiety, 3,6-di-O-acetylcellulose and 2,6-di-O-acetyl cellulose were all synthesized and the reactivity of hydroxyl groups in anhydro-glucose units was in the order C-6>C-3>C-2. This work provides an alternative way to make WSCA, meanwhile, also services as a reminder that the activity of EmimAc toward carbohydrate as acylating reagents could be a problem, because the expected acylated products may not be resulted and recycling of this ionic liquid could also be difficult. PMID:27644545

  3. Synthesis of Highly Polymerized Water-soluble Cellulose Acetate by the Side Reaction in Carboxylate Ionic Liquid 1-ethyl-3-methylimidazolium Acetate

    NASA Astrophysics Data System (ADS)

    Pang, Jinhui; Liu, Xin; Yang, Jun; Lu, Fachuang; Wang, Bo; Xu, Feng; Ma, Mingguo; Zhang, Xueming

    2016-09-01

    In the present study, we describe a novel one-step method to prepare water-soluble cellulose acetate (WSCA) with higher degree of polymerization values (DP = 650–680) by in situ activation of carboxyl group in ionic liquid. First of all, cellulose was dissolved in 1-ethyl-3-methylimidazolium acetate (EmimAc) and reacted with dichloroacetyl chloride (Cl2AcCl) in order to make cellulose dichloroacetate. Under various conditions, a series of water soluble products were produced. Elemental analysis and NMR results confirmed that they were cellulose acetate with DS (degree of substitution) values in the range from 0.30 to 0.63. NMR studies demonstrated that Cl2AcCl reacted with acetate anion of EmimAc producing a mixed anhydride that acetylated cellulose. Other acylating reagents such as benzoyl chloride, chloroacetyl chloride can also work similarly. 2D NMR characterization suggested that 6-mono-O-acetyl moiety, 3,6-di-O-acetylcellulose and 2,6-di-O-acetyl cellulose were all synthesized and the reactivity of hydroxyl groups in anhydro-glucose units was in the order C-6>C-3>C-2. This work provides an alternative way to make WSCA, meanwhile, also services as a reminder that the activity of EmimAc toward carbohydrate as acylating reagents could be a problem, because the expected acylated products may not be resulted and recycling of this ionic liquid could also be difficult.

  4. Synthesis of Highly Polymerized Water-soluble Cellulose Acetate by the Side Reaction in Carboxylate Ionic Liquid 1-ethyl-3-methylimidazolium Acetate.

    PubMed

    Pang, Jinhui; Liu, Xin; Yang, Jun; Lu, Fachuang; Wang, Bo; Xu, Feng; Ma, Mingguo; Zhang, Xueming

    2016-01-01

    In the present study, we describe a novel one-step method to prepare water-soluble cellulose acetate (WSCA) with higher degree of polymerization values (DP = 650-680) by in situ activation of carboxyl group in ionic liquid. First of all, cellulose was dissolved in 1-ethyl-3-methylimidazolium acetate (EmimAc) and reacted with dichloroacetyl chloride (Cl2AcCl) in order to make cellulose dichloroacetate. Under various conditions, a series of water soluble products were produced. Elemental analysis and NMR results confirmed that they were cellulose acetate with DS (degree of substitution) values in the range from 0.30 to 0.63. NMR studies demonstrated that Cl2AcCl reacted with acetate anion of EmimAc producing a mixed anhydride that acetylated cellulose. Other acylating reagents such as benzoyl chloride, chloroacetyl chloride can also work similarly. 2D NMR characterization suggested that 6-mono-O-acetyl moiety, 3,6-di-O-acetylcellulose and 2,6-di-O-acetyl cellulose were all synthesized and the reactivity of hydroxyl groups in anhydro-glucose units was in the order C-6>C-3>C-2. This work provides an alternative way to make WSCA, meanwhile, also services as a reminder that the activity of EmimAc toward carbohydrate as acylating reagents could be a problem, because the expected acylated products may not be resulted and recycling of this ionic liquid could also be difficult.

  5. Development of a functionalized polymeric ionic liquid monolith for solid-phase microextraction of polar endocrine disrupting chemicals in aqueous samples coupled to high-performance liquid chromatography.

    PubMed

    Feng, Juanjuan; Sun, Min; Bu, Yanan; Luo, Chuannan

    2015-09-01

    Ionic liquids (ILs) have been efficiently used as a "designer sorbent" in sample preparation. A novel 1-(3-aminopropyl)-3-(4-vinylbenzyl)imidazolium 4-styrenesulfonate IL monomer was synthesized and copolymerized with 1,6-di(3-vinylimidazolium) hexane bishexafluorophosphate IL as cross-linking agent to prepare a cross-linked polymeric ionic liquids (PILs) monolith. Coupled to high-performance liquid chromatography (HPLC), the PILs monolith was used as a solid-phase microextraction (SPME) sorbent to extract some polar endocrine disrupting chemical (EDCs) such as estrogens, bisphenol A, and phthalate esters in aqueous samples. Preparation and extraction conditions were investigated and optimized to obtain satisfactory extraction efficiency. Limits of detection (LODs) of the proposed method for three steroid estrogens and bisphenol A were 0.25 and 0.2 μg L(-1), respectively, which were lower than or comparable to some other sample preparation methods. Intra- and inter-day repeatability for all the analytes was 2.2-12%. The monolith-to-monolith repeatability was 7.4-15%. The extraction performance of the method for analysis of target estrogens in treated domestic wastewater was investigated and compared with a dispersive liquid-liquid microextraction (DLLME) method. The proposed SPME method provided better sensitivity and higher resistance to matrix interferences. PMID:26220716

  6. Nuclear microanalysis of the human amnion: A study of ionic cellular exchanges

    NASA Astrophysics Data System (ADS)

    Razafindrabe, L.; Moretto, Ph.; Llabador, Y.; Simonoff, M.; Bara, M.; Guiet-Bara, A.

    1995-09-01

    The epithelial cells of the human amniotic membrane have been extensively studied by electrophysiologists with the aim of elucidating the mechanisms of transmembrane ionic transfers. In order to provide complementary information about this model, nuclear microanalysis was performed using the CENBG ion microbeam. Quantitative mapping of the human amnion was carried out and the distributions of most mono- and divalent ions involved in cellular pathways (Na +, Mg 2+, Cl -, Ca 2+) were determined. The ionic cellular content was also compared, before and after incubation in a Hanks' physiological fluid and the resultant ions transfers were determined. The aim of this paper is to expose the advances of this experimental model, more particularly after the development of simulation programs which improved the accuracy of PIXE analysis in the measurement of low energy X-rays emitters. Statistically significant results can now be extracted and can be explained taking into account the results of previous electrophysiological experiments.

  7. Novel ion-exchange membranes for electrodialysis prepared by radiation-induced graft polymerization

    SciTech Connect

    Tsuneda, Satoshi; Saito, Kyoichi; Misuhara, Hisashi; Sugo, Takanobu

    1995-11-01

    Ion-exchange membranes have been used to concentrate seawater to produce salt as well as to desalinate brackish water to render it potable. Also, the interest in applications of ion-exchange membranes as separators for electrodialytic desalination of bioproducts and separators in hydrogen-oxygen fuel cells has been growing. Novel ion-exchange membranes containing sulfonic acid (SO{sub 3}H) and trimethyl ammonium [N(CH{sub 3}){sub 3}] groups were prepared by a simple method of radiation-induced cografting of sodium styrene sulfonate (SSS) with acrylic acid (AAc) and vinyl benzyl trimethyl ammonium chloride (VBTAC) with 2-hydroxyethyl methacrylate (HEMA), onto a polyethylene film with a thickness of 50 {micro}m. The high density graft chain was introduced throughout the polyethylene film. The maximum cation- and anion-exchange capacities of the resultant membranes were 2.5 and 1.3 mol/kg, receptively. These membranes exhibited an electrical resistance one order lower than commercially available ion-exchange membranes; for example, 12 h cografting provided cation- and anion-exchange membranes whose electrical resistances in a 0.5 M NaCl solution were 0.25 and 0.85 {Omega} cm{sup 2}, respectively. From the evaluation of electrodialytic desalination in a batch mode, using a pair of the graft-type ion-exchange membranes, the time required to achieve 99.5% desalination of the initial 0.5 M NaCl solutions was reduced to 85% comparing with that of the commercial ion-exchange membranes.

  8. Sorption of chlorimuron-ethyl on montmorillonite clays: effects of exchangeable cations, pH, and ionic strength.

    PubMed

    Ren, Wenjie; Teng, Ying; Zhou, Qixing; Paschke, Albrecht; Schüürmann, Gerrit

    2014-10-01

    Sorption interaction of chlorimuron-ethyl with montmorillonite clays was investigated under varied types of exchangeable cation, pH, and ionic strength conditions. Chlorimuron-ethyl sorption on bentonites exhibited pronounced cation dependency, and the sorption ability increased as the sequence Ca(2+)- < Na(+)- < Al(3+)- < Fe(3+)-bentonite, due to different sorption mechanisms, whereas the cation dependency was influenced by the clay type and much weaker for montmorillonites. The decrease of pH at the range of 4.0-6.0 prominently increased sorption of chlorimuron-ethyl on all cation-exchanged montmorillonite clays, and nearly a neglected sorption (about 2 %) can be observed at pH over 7.0. In the presence of CaCl2, sorption of chlorimuron-ethyl on Fe(3+)-bentonite was promoted because of complexion of Ca(2+) and the surface of Fe(3+)-bentonite. However, as the concentration of CaCl2 increased, chlorimuron-ethyl sorption on Ca(2+)- and Fe(3+)-exchanged bentonite decreased, suggesting that Ca bridging was not the prevailing mechanism for sorption of chlorimuron-ethyl on these clays. Furthermore, chlorimuron-ethyl sorption was relatively sensitive to pH, and the change of pH may obscure effect of other factors on the sorption, so it was quite necessary to control pH at a constant value when the effect of other factor was being studied. PMID:25028319

  9. Electrophysiological characterization of ionic transport by the retinal exchanger expressed in human embryonic kidney cells.

    PubMed Central

    Navanglone, A; Rispoli, G; Gabellini, N; Carafoli, E

    1997-01-01

    The retinal Na+:Ca2+, K+exchanger cDNA was transiently expressed in human embryonic kidney (HEK 293) cells by transfection with plasmid DNA. The correct targeting of the expressed protein to the plasma membrane was confirmed by immunocytochemistry. The reverse exchange offrent (Ca2+ imported per Na+ extruded) was measured in whole-cell voltage-clamp experiments after intracellular perfusion with Na+ (Na+i, 128 mM) and extracellular perfusion with Ca2+ (Ca2o+, 1 mM) and Ko+ (20 mM). As expected, the exchange current was suppressed by removing Ca2o+. Surprisingly, however, it was also abolished by increasing Na+o to almost abolish the Na+ gradient, and it was almost unaffected by the removal of Ko+. Apparently, then, at variance with the exchanger in the rod outer segment, the retinal exchanger expressed in 293 cells acts essentially as a Na+:Ca2+ exchanger and does not require K+ for its electrogenic activity. Images FIGURE 1 PMID:9199770

  10. Ionic strength dependence of cytochrome c structure and Trp-59 H/D exchange from ultraviolet resonance Raman spectroscopy.

    PubMed

    Liu, G Y; Grygon, C A; Spiro, T G

    1989-06-13

    Ultraviolet resonance Raman spectra are reported for cytochrome c (cyt c) in FeII and FeIII oxidation states at low (0.005 M) and high (0.9-1.5 M) ionic strength. With 200-nm excitation the amide band intensities are shown to remain constant, establishing that redox state and ionic strength have no influence on the alpha-helical content. The tyrosine 830/850-cm-1 doublet, however, shows a loss in 830-cm-1 intensity at I = 0.005 M for the FeIII protein, suggesting a weakening or a loss of H-bonding from an internal tyrosine, probably Tyr-48, which is H-bonded to a heme propionate group in cyt c crystals. Excitation profiles of tryptophan peak at approximately 229 nm for both FeII and FeIII forms of cyt c, but at approximately 218 nm for aqueous tryptophan. The approximately 2200-cm-1 red shift of the resonant electronic transition is attributed to the Trp-59 residue being buried and H-bonded. Consistent with this Trp environment, the H-bond-sensitive 877-cm-1 Trp band is strong and sharp, and the 1357/1341-cm-1 doublet has a large intensity ratio, approximately 1.5, for both FeII and FeIII cyt c. The 877-cm-1-band frequency shifts to 860 cm-1 when the Trp indole proton is replaced by a deuteron. This band was used to show that Trp H/D exchange in D2O is much faster for FeIII than FeII cyt c. The half-time for exchange at room temperature is estimated to be approximately 30 and approximately 5 h, respectively, for FeII and FeIII when examined at I = 0.005.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. A general halide-to-anion switch for imidazolium-based ionic liquids and oligocationic systems using anion exchange resins (A- form).

    PubMed

    Alcalde, Ermitas; Dinarès, Immaculada; Ibáñez, Anna; Mesquida, Neus

    2011-03-21

    Further studies on the application of an AER (A(-) form) method broadened the anion exchange scope of representative ionic liquids and bis(imidazolium) systems. Depending on the hydrophobicity nature of the targeted imidazolium species and counteranions, different organic solvents were used to swap halides for assorted anions, proceeding in excellent to quantitative yields.

  12. [Effect of insulin on germination and ionic exchange in Raphanus sativus (author's transl)].

    PubMed

    Frasquet, M I; Viña, J; Frasquet, M; Ferriol, A; Alvarez de Laviada, T; Antón, V

    1978-06-01

    Hypoglycemic sulfamide BZ-55 activates or inhibits germination of Raphanus sativus, depending upon the dosis. Since this drug acts upon the glycemia by increasing the secretion and action of insulin, the influence of this hormone on germination and ionic changes (Na+-K+) between seeds and culture medium, were studied. Seeds were incubated during 72 h with different concentrations of insulin in 10 ml deionized water or in 10 ml 18 mM K+ (KCl) solutions at 37 degrees C in vapor saturated atmosphere. A solution of 0.125 IU insulin/ml in water increases the germination to 110% whereas 0.175 IU insulin/ml inhibits it to 40% against controls. Further increases in insulin concentration always inhibit germination. Similar results have been obtained with K+ containing media. Germination rate changes in a small concentration range suggest that insulin might affect an enzymatic activity in the seed.

  13. Properties of ionic liquids on Au surfaces: non-conventional anion exchange reactions with carbonate.

    PubMed

    Ratel, Mathieu; Branca, Mathieu; Breault-Turcot, Julien; Zhao, Sandy Shuo; Chaurand, Pierre; Schmitzer, Andreea R; Masson, Jean-Francois

    2011-10-14

    A simple anion metathesis in diluted aqueous carbonate at room temperature affords 1-(12-mercaptododecyl)-3-methyl-imidazolium carbonate (MDMI-HCO(3)) from MDMI salts self-assembled on gold films and nanoparticles. The properties of MDMI-SAM differ from MDMI in solution, for which the anion exchange reaction does not proceed. PMID:21879044

  14. Dicationic polymeric ionic-liquid-based magnetic material as an adsorbent for the magnetic solid-phase extraction of organophosphate pesticides and polycyclic aromatic hydrocarbons.

    PubMed

    Jiang, Qiong; Liu, Qin; Chen, Qiliang; Zhao, Wenjie; Xiang, Guoqiang; He, Lijun; Jiang, Xiuming; Zhang, Shusheng

    2016-08-01

    Magnetic particles modified with a dicationic polymeric ionic liquid are described as a new adsorbent in magnetic solid-phase extraction. They were obtained through the copolymerization of a 1,8-di(3-vinylimidazolium)octane-based ionic liquid with vinyl-modified SiO2 @Fe3 O4 , and were characterized by FTIR spectroscopy, X-ray diffraction, and vibrating sample magnetometry. The modified magnetic particles are effective in the extraction of organophosphate pesticides and polycyclic aromatic hydrocarbons. Also, they can provide different extraction performance for the selected analytes including fenitrothion, parathion, fenthion, phoxim, phenanthrene, and fluoranthene, where the extraction efficiency is found to be in agreement with the hydrophobicity of analytes. Various factors influencing the extraction efficiency, such as, the amount of adsorbent, extraction, and desorption time, and type and volume of the desorption solvent, were optimized. Under the optimized conditions, a good linearity ranging from 1-100 μg/L is obtained for all analytes, except for parathion (2-200 μg/L), where the correlation coefficients varied from 0.9960 to 0.9998. The limits of detection are 0.2-0.8 μg/L, and intraday and interday relative standard deviations are 1.7-7.4% (n = 5) and 3.8-8.0% (n = 3), respectively. The magnetic solid-phase extraction combined with high-performance liquid chromatography can be applied for the detection of trace targets in real water samples with satisfactory relative recoveries and relative standard deviations. PMID:27357486

  15. Isothermal and non-isothermal crystallization kinetics of PVA + ionic liquid [BDMIM][BF4]-based polymeric films

    NASA Astrophysics Data System (ADS)

    Saroj, A. L.; Chaurasia, S. K.; Kataria, Shalu; Singh, R. K.

    2016-06-01

    The effect of ionic liquid (IL), 1-butyl-2,3-dimethylimidazolium tetrafluoroborate [BDMIM][BF4], on crystallization behavior of poly(vinyl alcohol) (PVA) has been studied by isothermal and non-isothermal differential scanning calorimetry techniques. The PVA + IL based polymer electrolyte films have been prepared using solution casting technique. To describe the isothermal and non-isothermal crystallization kinetics, several kinetic equations have been employed on PVA + IL based films. There is strong dependence of the peak crystallization temperature (Tc), relative degree of crystallity (Xt), half-time of crystallization (t1/2), crystallization rate constants (Avrami Kt and Tobin AT), and Avrami (n) and Tobin (nT) exponents on the cooling rate and IL loading.

  16. Molecular interactions in the ionic liquid emim acetate and water binary mixtures probed via NMR spin relaxation and exchange spectroscopy.

    PubMed

    Allen, Jesse J; Bowser, Sage R; Damodaran, Krishnan

    2014-05-01

    Interactions of ionic liquids (ILs) with water are of great interest for many potential IL applications. 1-Ethyl-3-methylimidazolium (emim) acetate, in particular, has shown interesting interactions with water including hydrogen bonding and even chemical exchange. Previous studies have shown the unusual behavior of emim acetate when in the presence of 0.43 mole fraction of water, and a combination of NMR techniques is used herein to investigate the emim acetate-water system and the unusual behavior at 0.43 mole fraction of water. NMR relaxometry techniques are used to describe the effects of water on the molecular motion and interactions of emim acetate with water. A discontinuity is seen in nuclear relaxation behavior at the concentration of 0.43 mole fraction of water, and this is attributed to the formation of a hydrogen bonded network. EXSY measurements are used to determine the exchange rates between the H2 emim proton and water, which show a complex dependence on the concentration of the mixture. The findings support and expand our previous results, which suggested the presence of an extended hydrogen bonding network in the emim acetate-water system at concentrations close to 0.50 mole fraction of H2O. PMID:24654003

  17. Independent control of the shape and composition of ionic nanocrystals through sequential cation exchange reactions

    SciTech Connect

    Luther, Joseph Matthew; Zheng, Haimei; Sadtler, Bryce; Alivisatos, A. Paul

    2009-07-06

    Size- and shape-controlled nanocrystal growth is intensely researched for applications including electro-optic, catalytic, and medical devices. Chemical transformations such as cation exchange overcome the limitation of traditional colloidal synthesis, where the nanocrystal shape often reflects the inherent symmetry of the underlying lattice. Here we show that nanocrystals, with established synthetic protocols for high monodispersity, can be templates for independent composition control. Specifically, controlled interconversion between wurtzite CdS, chalcocite Cu2S, and rock salt PbS occurs while preserving the anisotropic dimensions unique to the as-synthesized materials. Sequential exchange reactions between the three sulfide compositions are driven by the disparate solubilites of the metal ion exchange pair in specific coordinating molecules. Starting with CdS, highly anisotropic PbS nanorods are created, which serve as an important material for studying strong 2-dimensional quantum confinement, as well as for optoelectronic applications. Furthermore, interesting nanoheterostructures of CdS|PbS are obtained by precise control over ion insertion and removal.

  18. In situ-polymerized wicks for passive water management in proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Strickland, Daniel G.; Santiago, Juan G.

    Air-delivery is typically the largest parasitic loss in PEM fuel cell systems. We develop a passive water management system that minimizes this loss by enabling stable, flood-free performance in parallel channel architectures, at very low air stoichiometries. Our system employs in situ-polymerized wicks which conform to and coat cathode flow field channel walls, thereby spatially defining regions for water and air transport. We first present the fabrication procedure, which incorporates a flow field plate geometry comparable to many state-of-the-art architectures (e.g., stamped metal or injection molded flow fields). We then experimentally compare water management flow field performance versus a control case with no wick integration. At the very low air stoichiometry of 1.15, our system delivers a peak power density of 0.68 W cm -2. This represents a 62% increase in peak power over the control case. The open channel and manifold geometries are identical for both cases, and we demonstrate near identical inlet-to-outlet cathode pressure drops at all fuel cell operating points. Our water management system therefore achieves significant performance enhancement without introducing additional parasitic losses.

  19. A highly selective voltammetric sensor for nanomolar detection of mercury ions using a carbon ionic liquid paste electrode impregnated with novel ion imprinted polymeric nanobeads.

    PubMed

    Bahrami, Azam; Besharati-Seidani, Abbas; Abbaspour, Abdolkarim; Shamsipur, Mojtaba

    2015-03-01

    This work reports the preparation of a voltammetric sensor for selective recognition and sensitive determination of mercury ions using a carbon ionic liquid paste electrode (CILE) impregnated with novel Hg(2+)-ion imprinted polymeric nanobeads (IIP) based on dithizone, as a suitable ligand for complex formation with Hg(2+) ions. The differential pulse anodic stripping voltammetric technique was employed to investigate the performance of the prepared IIP-CILE for determination of hazardous mercury ions. The designed modified electrode revealed linear responses in the ranges of 0.5nM-10nM and 0.08μM-2μM with a limit of detection of 0.1nM (S/N=3). It was found that the peak currents of the modified electrode for Hg(2+) ions were at a maximum value in phosphate buffer of pH4.5. The optimized preconcentration potential and accumulation time were to be -0.9V and 35s, respectively. The applicability of the proposed sensor to mercury determination in waste water samples is reported. PMID:25579915

  20. Graphene oxide reinforced polymeric ionic liquid monolith solid-phase microextraction sorbent for high-performance liquid chromatography analysis of phenolic compounds in aqueous environmental samples.

    PubMed

    Sun, Min; Bu, Yanan; Feng, Juanjuan; Luo, Chuannan

    2016-01-01

    A graphene oxide reinforced polymeric ionic liquids monolith was obtained by copolymerization of graphene oxide doped 1-(3-aminopropyl)-3-(4-vinylbenzyl)imidazolium 4-styrenesulfonate monomer and 1,6-di-(3-vinylimidazolium) hexane bihexafluorophosphate cross-linking agent. Coupled to high-performance liquid chromatography, the monolith was used as a solid-phase microextraction sorbent to analyze several phenolic compounds in aqueous samples. Under the optimized extraction and desorption conditions, linear ranges were 5-400 μg/L for 3-nitrophenol, 2-nitrophenol, and 2,5-dichlorophenol and 2-400 μg/L for 4-chlorophenol, 2-methylphenol, and 2,4,6-trichlorophenol (R(2) = 0.9973-0.9988). The limits of detection were 0.5 μg/L for 3-nitrophenol and 2-nitrophenol and 0.2 μg/L for the rest of the analytes. The proposed method was used to determine target analytes in groundwater from an industrial park and river water. None of the analytes was detected. Relative recoveries were in the range of 75.5-113%.

  1. Sensitive determination of estrogens in environmental waters treated with polymeric ionic liquid-based stir cake sorptive extraction and liquid chromatographic analysis.

    PubMed

    Chen, Lei; Mei, Meng; Huang, Xiaojia; Yuan, Dongxing

    2016-05-15

    A simple, sensitive and environmentally friendly method using polymeric ionic liquid-based stir cake sorptive extraction followed by high performance liquid chromatography with diode array detection (HPLC/DAD) has been developed for efficient quantification of six selected estrogens in environmental waters. To extract trace estrogens effectively, a poly (1-ally-3-vinylimidazolium chloride-co-ethylene dimethacrylate) monolithic cake was prepared and used as the sorbent of stir cake sorptive extraction (SCSE). The effects of preparation conditions of sorbent and extraction parameters of SCSE for estrogens were investigated and optimized. Under optimal conditions, the developed method showed satisfactory analytical performance for targeted analytes. Low limits of detection (S/N=3) and quantification limits (S/N=10) were achieved within the range of 0.024-0.057 µg/L and 0.08-0.19 µg/L, respectively. Good linearity of method was obtained for analytes with the correlation coefficients (R(2)) above 0.99. At the same time, satisfactory method repeatability and reproducibility was achieved in terms of intra- and inter-day precisions, respectively. Finally, the established SCSE-HPLC/DAD method was successfully applied for the determination of estrogens in different environmental water samples. Recoveries obtained for the determination of estrogens in spiked samples ranged from 71.2% to 108%, with RSDs below 10% in all cases.

  2. The controlled photoactivity of nanoparticles derived from ionic interactions between a water soluble polymeric photosensitizer and polysaccharide quencher.

    PubMed

    Park, Wooram; Park, Sin-jung; Na, Kun

    2011-11-01

    In order to design a water soluble polymeric photosensitizer (WPS) with controllable photoactivity, a nano-photosensitizer (NPS) was prepared from a polyelectrolyte complex between polyethylene glycol-polyethylenimine-chlorine e6 conjugate (PEG-PEI-Ce6) and Black Hole Quencher-3 chondroitin sulfate conjugate (BHQ-3-CS). NPSs have a unimodal size distribution below 100 nm. Photoquenching of the NPS was dependent on the weight ratio of BHQ-3-CS/WPS. This phenomenon was maintained in a salt condition up to 300 mm, indicating that the photoactivity of the NPS disappears in the normal blood stream of the body. The quenched photoactivity was restored by the enzyme degradation of BHQ-3-CS after esterase treatment. In a HCT-116 (human colon cancer) cell test, the rapid cellular internalization of the NPS without any other ligands was observed by confocal imaging. Upon light irradiation after internalization, phototoxicity was detected via MTT colorimetric assay. Also, when the NPS was subcutaneously injected in both tumoral and normal regions of HCT-116 tumor-bearing mice, the fluorescence signal in the tumors rapidly increased compared to the normal region due to the enzymatic-triggered dissociation of the NPS in vivo. These results suggest that the NPS can provide both tumor diagnosis and therapy simultaneously, and has great potential for biological studies and clinical treatments of various tumors. PMID:21803417

  3. Characterization of self-assembled functional polymeric nanostructures: I. magnetic nanostructures from metallopolymers II. Zwitterionic polymer vesicles in ionic liquid

    NASA Astrophysics Data System (ADS)

    Maddikeri, Raghavendra Raj

    matrix is confined between the non-magnetic cylinders, had second highest and lamellar morphology with least confinement among BCPs, exhibited lowest coercivity. The proposed hypothesis was further tested by systematically varying the dipolar interactions between the SPM cobalt nanoparticles by reducing the density of cobalt within the cylindrical domains and varying the dimensions of the cylindrical domains (i.e. diameter). A series of novel ferrocene-cobalt containing block copolymers were developed and cobalt density within the cylindrical domains of BCP was varied by changing the chemical composition of the metal functionalized block. Further, the diameter of the cylindrical domains was varied by varying the molecular weight of the cobalt-containing BCPs. These studies allowed us to understand the fundamental correlations between the self-assembled nanostructures and their macroscopic magnetic properties. In the second part of the thesis, a novel amphiphilic block copolymer (ABC), composed of a hydrophilic zwitterionic block and a hydrophobic PS block, was synthesized by ROMP. The formation of zwitterionic vesicles in an ionic liquid, as well as in PBS buffer, was confirmed by TEM and DLS characterization. The dispersion of vesicles within ionic liquid enabled the usage of conventional, room temperature TEM to visualize them in their solution state. This technique of materials characterization could be extended for the visualization of other hydrophilic soft matter.

  4. Sustainable polymerizations in recoverable microemulsions.

    PubMed

    Chen, Zhenzhen; Yan, Feng; Qiu, Lihua; Lu, Jianmei; Zhou, Yinxia; Chen, Jiaxin; Tang, Yishan; Texter, John

    2010-03-16

    Free radical and atom-transfer radical polymerizations were conducted in monomer/ionic liquid microemulsions. After the polymerization and isolation of the resultant polymers, the mixture of the catalyst and ionic liquids (surfactant and continuous phase) can be recovered and reused, thereby dramatically improving the environmental sustainability of such chemical processing. The addition of monomer to recovered ionic liquid mixtures regenerates transparent, stable microemulsions that are ready for the next polymerization cycle upon addition of initiator. The method combines the advantages of IL recycling and microemulsion polymerization and minimizes environmental disposable effects from surfactants and heavy metal ions. PMID:20170175

  5. Exchange of organic radicals with organo-cobalt complexes formed in the living radical polymerization of vinyl acetate.

    PubMed

    Li, Shan; de Bruin, Bas; Peng, Chi-How; Fryd, Michael; Wayland, Bradford B

    2008-10-01

    Exchange of organic radicals between solution and organo-cobalt complexes is experimentally observed and the reaction pathway is probed through DFT calculations. Cyanoisopropyl radicals from AIBN (2,2'-azobisisobutyronitrile) enter solutions of cobalt(II) tetramesityl porphyrin ((TMP)Co(II)*, 1) and vinyl acetate (VAc) in benzene and react to produce transient hydride (TMP)Co-H and radicals (*CH(OAc)CH2C(CH3)2CN (R1*)) that proceed on to form organo-cobalt complexes (TMP)Co-CH(OAc)CH3 (4, Co-R2) and (TMP)Co-CH(OAc)CH2C(CH3)2CN (3, Co-R1), respectively. Rate constants for cyanoisopropyl radical addition with vinyl acetate and hydrogen atom transfer to (TMP)Co(II)* are reported through kinetic studies for the formation and transformation of organo-cobalt species in this system. Rate constants for near-degenerate exchanges of radicals in solution with organo-cobalt complexes are deduced from (1)H NMR studies and kinetic modeling. DFT computations revealed formation of an unsymmetrical adduct of (TMP)Co-CH(OAc)CH3 (4) with *CH(OAc)CH3 (R2*) and support an associative pathway for radical interchange through a three-centered three-electron transition state [R...Co...R]. Associative radical interchange of the latent radical groups in organo-cobalt porphyrin complexes with freely diffusing radicals in solution that is observed in this system provides a pathway for mediation of living radical polymerization of vinyl acetate.

  6. Preparation of high-capacity, weak anion-exchange membranes by surface-initiated atom transfer radical polymerization of poly(glycidyl methacrylate) and subsequent derivatization with diethylamine

    NASA Astrophysics Data System (ADS)

    Qian, Xiaolei; Fan, Hua; Wang, Chaozhan; Wei, Yinmao

    2013-04-01

    Ion-exchange membrane is of importance for the development of membrane chromatography. In this work, a high-capacity anion-exchange membrane was prepared by grafting of glycidyl methacrylate (GMA) onto the surface of regenerated cellulose (RC) membranes via surface-initiated atom transfer radical polymerization (SI-ATRP) and subsequent derivatization with diethylamine. Attenuated total reflectance Fourier-transform infrared (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were used to characterize changes in the chemical functionality, surface topography and pore morphology of the modified membranes. The static capacity of the prepared anion-exchange membrane was evaluated with bovine serum albumin (BSA) as a model protein. The results indicated that the anion-exchange membrane which could reach a maximum capacity of 96 mg/mL for static adsorption possesses a higher adsorption capacity, and the adsorption capacity increases with the polymerization time. The effect of pH and salt concentration confirmed that the adsorption of BSA followed ion-exchange mechanism. The established method would have potential application in the preparation of anion-exchange membrane.

  7. Ion Exchange Distribution Coefficient Tests and Computer Modeling at High Ionic Strength Supporting Technetium Removal Resin Maturation

    SciTech Connect

    Nash, Charles A.; Hamm, L. Larry; Smith, Frank G.; McCabe, Daniel J.

    2014-12-19

    The primary treatment of the tank waste at the DOE Hanford site will be done in the Waste Treatment and Immobilization Plant (WTP) that is currently under construction. The baseline plan for this facility is to treat the waste, splitting it into High Level Waste (HLW) and Low Activity Waste (LAW). Both waste streams are then separately vitrified as glass and poured into canisters for disposition. The LAW glass will be disposed onsite in the Integrated Disposal Facility (IDF). There are currently no plans to treat the waste to remove technetium, so its disposition path is the LAW glass. Due to the water solubility properties of pertechnetate and long half-life of 99Tc, effective management of 99Tc is important to the overall success of the Hanford River Protection Project mission. To achieve the full target WTP throughput, additional LAW immobilization capacity is needed, and options are being explored to immobilize the supplemental LAW portion of the tank waste. Removal of 99Tc, followed by off-site disposal, would eliminate a key risk contributor for the IDF Performance Assessment (PA) for supplemental waste forms, and has potential to reduce treatment and disposal costs. Washington River Protection Solutions (WRPS) is developing some conceptual flow sheets for supplemental LAW treatment and disposal that could benefit from technetium removal. One of these flowsheets will specifically examine removing 99Tc from the LAW feed stream to supplemental immobilization. To enable an informed decision regarding the viability of technetium removal, further maturation of available technologies is being performed. This report contains results of experimental ion exchange distribution coefficient testing and computer modeling using the resin SuperLig® 639a to selectively remove perrhenate from high ionic strength simulated LAW. It is advantageous to operate at higher concentration in order to treat the waste

  8. Structural basis of thymosin-β4/profilin exchange leading to actin filament polymerization

    PubMed Central

    Xue, Bo; Leyrat, Cedric; Grimes, Jonathan M.; Robinson, Robert C.

    2014-01-01

    Thymosin-β4 (Tβ4) and profilin are the two major sequestering proteins that maintain the pool of monomeric actin (G-actin) within cells of higher eukaryotes. Tβ4 prevents G-actin from joining a filament, whereas profilin:actin only supports barbed-end elongation. Here, we report two Tβ4:actin structures. The first structure shows that Tβ4 has two helices that bind at the barbed and pointed faces of G-actin, preventing the incorporation of the bound G-actin into a filament. The second structure displays a more open nucleotide binding cleft on G-actin, which is typical of profilin:actin structures, with a concomitant disruption of the Tβ4 C-terminal helix interaction. These structures, combined with biochemical assays and molecular dynamics simulations, show that the exchange of bound actin between Tβ4 and profilin involves both steric and allosteric components. The sensitivity of profilin to the conformational state of actin indicates a similar allosteric mechanism for the dissociation of profilin during filament elongation. PMID:25313062

  9. Single-Site Heterogeneous Catalysts for Olefin Polymerization Enabled by Cation Exchange in a Metal-Organic Framework.

    PubMed

    Comito, Robert J; Fritzsching, Keith J; Sundell, Benjamin J; Schmidt-Rohr, Klaus; Dincă, Mircea

    2016-08-17

    The manufacture of advanced polyolefins has been critically enabled by the development of single-site heterogeneous catalysts. Metal-organic frameworks (MOFs) show great potential as heterogeneous catalysts that may be designed and tuned on the molecular level. In this work, exchange of zinc ions in Zn5Cl4(BTDD)3, H2BTDD = bis(1H-1,2,3-triazolo[4,5-b],[4',5'-i])dibenzo[1,4]dioxin) (MFU-4l) with reactive metals serves to establish a general platform for selective olefin polymerization in a high surface area solid promising for industrial catalysis. Characterization of polyethylene produced by these materials demonstrates both molecular and morphological control. Notably, reactivity approaches single-site catalysis, as evidenced by low polydispersity indices, and good molecular weight control. We further show that these new catalysts copolymerize ethylene and propylene. Uniform growth of the polymer around the catalyst particles provides a mechanism for controlling the polymer morphology, a relevant metric for continuous flow processes.

  10. Beneficial phosphate recovery from reverse osmosis (RO) concentrate of an integrated membrane system using polymeric ligand exchanger (PLE).

    PubMed

    Kumar, Manish; Badruzzaman, Mohammad; Adham, Samer; Oppenheimer, Joan

    2007-05-01

    Phosphorus (P) discharge to surface water is a major environmental problem. Wastewater treatment is targeted towards removal of this nutrient to prevent degradation of surface water. Integrated membrane systems (IMS) are increasingly being considered for wastewater reclamation, and provide excellent removal of P compounds. However, reverse osmosis (RO), which forms an integral part of these IMSs, concentrates most dissolved substances including P-species such as phosphates in the RO waste stream. In this study, removal of phosphate from this stream using polymeric ligand exchange (PLE) resins was investigated. Further, the possibility of phosphate recovery through struvite (MgNH(4)PO(4).6H(2)O) precipitation was tested. Struvite has been promoted as a slow release fertilizer in recent years. This study demonstrates that PLEs can be successfully used to remove phosphate from RO-concentrate, and to recover more than 85% of the adsorbed phosphorus from the exhausted media and precipitated as a beneficial product (struvite). The approach, presented in this study, suggests advantages of providing economic benefit from a waste product (RO) while avoiding phosphorus discharge to the environment.

  11. Protein adsorption on novel acrylamido-based polymeric ion-exchangers. III. Salt concentration effects and elution behavior.

    PubMed

    Hunter, A K; Carta, G

    2001-09-28

    The effect of salt concentration on the adsorption and desorption of BSA has been determined for a polymeric anion-exchanger based on acrylamido monomers. The material investigated possesses a high adsorption capacity at low salt concentration and the bound protein can be recovered quantitatively at high salt concentrations. The effects of salt on adsorption and desorption rates were evaluated from batch and shallow-bed experiments, and a model was developed to describe the data quantitatively. The adsorption capacity decreases as the salt concentration is increased, but both adsorption and desorption rates increase at higher salt concentrations. The predictability of the behavior of columns packed with this material was examined by comparing model predictions and experimental results obtained in laboratory columns. In general, a good agreement was obtained between predicted and experimental breakthrough and elution profiles, especially in shorter columns. Thus, the model allows a prediction of the effects of column length, mobile phase flow-rate, protein feed concentration, and salt concentration on dynamic capacity, productivity, and on the concentration of product fractions. PMID:11681582

  12. Coordination Chemistry Inside Polymeric Nanoreactors: Interparticle Metal Exchange and Ionic Compound Vectorization in Phosphine-Functionalized Amphiphilic Polymer Latexes.

    PubMed

    Chen, Si; Gayet, Florence; Manoury, Eric; Joumaa, Ahmad; Lansalot, Muriel; D'Agosto, Franck; Poli, Rinaldo

    2016-04-25

    Stable latexes of hierarchically organized core-cross-linked polymer micelles that are functionalized at the core with triphenylphosphine (TPP@CCM) have been investigated by NMR spectroscopic analysis at both natural (ca. pH 5) and strongly basic (pH 13.6) pH values after core swelling with toluene. The core-shell interface structuring forces part of the hydrophilic poly(ethylene oxide) (PEO) chains to reside inside the hydrophobic core at both pH values. Loading the particle cores with [Rh(acac)(CO)2 ] (acac=acetylacetonate) at various Rh/P ratios yielded polymer-supported [Rh(acac)(CO)(TPP)] (TPP=triphenylphosphine). The particle-to-particle rhodium migration is very fast at natural pH, but slows down dramatically at high pH, whereas the size distribution of the nanoreactors remains unchanged. The slow migration at pH 13.6 leads to the generation of polymer-anchored [Rh(OH)(CO)(TPP)2 ], which is also generated immediately upon the addition of NaOH to the particles with a [Rh(acac)(CO)] loading of 50 %. Similarly, treatment of the same particles with NaCl yielded polymer-anchored [RhCl(CO)(TPP)2 ]. Interparticle coupling occurs during these rapid processes. These experiments prove that the major contribution to metal migration is direct core-core contact. The slow migration at the high pH value, however, must result from a pathway that does not involve core-core contact. The facile penetration of the polymer cores by NaOH and NaCl results from the presence of shell-linked poly(ethylene oxide) methyl ether functions both outside and inside the polymer core-shell interface.

  13. Coordination Chemistry Inside Polymeric Nanoreactors: Interparticle Metal Exchange and Ionic Compound Vectorization in Phosphine-Functionalized Amphiphilic Polymer Latexes.

    PubMed

    Chen, Si; Gayet, Florence; Manoury, Eric; Joumaa, Ahmad; Lansalot, Muriel; D'Agosto, Franck; Poli, Rinaldo

    2016-04-25

    Stable latexes of hierarchically organized core-cross-linked polymer micelles that are functionalized at the core with triphenylphosphine (TPP@CCM) have been investigated by NMR spectroscopic analysis at both natural (ca. pH 5) and strongly basic (pH 13.6) pH values after core swelling with toluene. The core-shell interface structuring forces part of the hydrophilic poly(ethylene oxide) (PEO) chains to reside inside the hydrophobic core at both pH values. Loading the particle cores with [Rh(acac)(CO)2 ] (acac=acetylacetonate) at various Rh/P ratios yielded polymer-supported [Rh(acac)(CO)(TPP)] (TPP=triphenylphosphine). The particle-to-particle rhodium migration is very fast at natural pH, but slows down dramatically at high pH, whereas the size distribution of the nanoreactors remains unchanged. The slow migration at pH 13.6 leads to the generation of polymer-anchored [Rh(OH)(CO)(TPP)2 ], which is also generated immediately upon the addition of NaOH to the particles with a [Rh(acac)(CO)] loading of 50 %. Similarly, treatment of the same particles with NaCl yielded polymer-anchored [RhCl(CO)(TPP)2 ]. Interparticle coupling occurs during these rapid processes. These experiments prove that the major contribution to metal migration is direct core-core contact. The slow migration at the high pH value, however, must result from a pathway that does not involve core-core contact. The facile penetration of the polymer cores by NaOH and NaCl results from the presence of shell-linked poly(ethylene oxide) methyl ether functions both outside and inside the polymer core-shell interface. PMID:27001452

  14. A novel polymeric ionic liquid-coated magnetic multiwalled carbon nanotubes for the solid-phase extraction of Cu, Zn-superoxide dismutase.

    PubMed

    Wen, Qian; Wang, Yuzhi; Xu, Kaijia; Li, Na; Zhang, Hongmei; Yang, Qin

    2016-10-01

    A novel magnetic adsorbent, benzyl groups functionalized imidazolium-based polymeric ionic liquid (PIL)-coated magnetic multiwalled carbon nanotubes (MWCNTs) (m-MWCNTs@PIL), has been successfully synthesized and applied for the extraction of Cu, Zn-superoxide dismutase (Cu, Zn-SOD). The m-MWCNTs@PIL were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrometry (FT-IR), thermal gravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM) and zeta-potential nanoparticles. In this method, the m-MWCNTs@PIL could interact with Cu, Zn-SOD through hydrogen bonding, π-π and electrostatic interactions. The extraction performance of the m-MWCNTs@PIL in the magnetic solid-phase extraction (MSPE) procedure was investigated, coupled with the determination by UV-vis spectrophotometer. Compared with m-MWCNTs@IL and m-MWCNTs, the m-MWCNTs@PIL exhibited the highest extraction capacity of 29.1 mg/g for Cu, Zn-SOD. The adsorbed Cu, Zn-SOD remained high specific activity after being eluted from m-MWCNTs@PIL by 1 moL/L NaCl solution. Besides, the m-MWCNTs@PIL could be easily recycled and successfully employed in the extraction of Cu, Zn-SOD from real samples. Under the optimal conditions, the precision, repeatability and stability of the proposed method were investigated and the RSDs were 0.29%, 1.68% and 0.54%, respectively. Recoveries were in the range of 82.7-102.3%, with the RSD between 3.47% and 5.35%. On the basis of these results, the developed method has great potential in the extraction of Cu, Zn-SOD or other analytes from biological samples. PMID:27639143

  15. Enhanced Ionic Conductivity and Power Generation Using Ion-Exchange Resin Beads in a Reverse-Electrodialysis Stack.

    PubMed

    Zhang, Bopeng; Gao, Haiping; Chen, Yongsheng

    2015-12-15

    Reverse electrodialysis (RED) is a promising technique for harvesting energy by mixing seawater with river water. The energy production is usually limited by ionic conductivity in dilute compartments of a RED system. Novel tests were conducted in this research, which used ion-exchange resin beads (IERB) to replace nonconductive spacer fabrics in RED compartments with dilute NaCl solution in a modified stack containing Fumasep FKS and Fumasep FAS membranes. We compared the conductivity of an IERB packed bed with that of an inert glass-beads-packed bed as a control to confirm IERB's effectiveness. When applied in a RED system, IERB decreased the stack resistance by up to 40%. The maximum gross power density improved by 83% in the RED stack compared to that in a regular RED stack at 1.3 cm/s average linear flow velocity. IERB-filled stack resistance was modeled. The model results fit well with experimental data, thereby confirming the effectiveness of the new approach presented here. The net power density is also estimated based on the measured pressure drop and pumping energy model. Both gross and net power density was improved by over 75% at higher flow rate. A net power density of 0.44 W/m(2) was achieved at a cell thickness of 500 μm. To the best of our knowledge, this research is the first to study the impact of IERB on power generation and establishes a new approach to improving the power performance of a RED system.

  16. Selective sorption of lead, cadmium and zinc ions by a polymeric cation exchanger containing nano-Zr(HPO3S)2.

    PubMed

    Zhang, Qingrui; Pan, Bingcai; Pan, Bingjun; Zhang, Weiming; Jia, Kun; Zhang, Quanxing

    2008-06-01

    A novel polymeric hybrid sorbent, namely ZrPS-001, was fabricated for enhanced sorption of heavy metal ions by impregnating Zr(HPO3S)2 (i.e., ZrPS) nanoparticles within a porous polymeric cation exchanger D-001. The immobilized negatively charged groups bound to the polymeric matrix D-001 would result in preconcentration and permeation enhancement of target metal ions prior to sequestration, and ZrPS nanoparticles are expected to sequester heavy metals selectively through an ion-exchange process. Highly effective sequestration of lead, cadmium, and zinc ions from aqueous solution can be achieved by ZrPS-001 even in the presence of competing calcium ion at concentration several orders of magnitude greater than the target species. The exhausted ZrPS-001 beads are amenable to regeneration with 6 M HCI solution for repeated use without any significant capacity loss. Fixed-bed column treatment of simulated waters containing heavy metals at high or trace levels was also performed. The content of heavy metals in treated effluent approached or met the WHO drinking water standard.

  17. Selective sorption of lead, cadmium and zinc ions by a polymeric cation exchanger containing nano-Zr(HPO3S)2.

    PubMed

    Zhang, Qingrui; Pan, Bingcai; Pan, Bingjun; Zhang, Weiming; Jia, Kun; Zhang, Quanxing

    2008-06-01

    A novel polymeric hybrid sorbent, namely ZrPS-001, was fabricated for enhanced sorption of heavy metal ions by impregnating Zr(HPO3S)2 (i.e., ZrPS) nanoparticles within a porous polymeric cation exchanger D-001. The immobilized negatively charged groups bound to the polymeric matrix D-001 would result in preconcentration and permeation enhancement of target metal ions prior to sequestration, and ZrPS nanoparticles are expected to sequester heavy metals selectively through an ion-exchange process. Highly effective sequestration of lead, cadmium, and zinc ions from aqueous solution can be achieved by ZrPS-001 even in the presence of competing calcium ion at concentration several orders of magnitude greater than the target species. The exhausted ZrPS-001 beads are amenable to regeneration with 6 M HCI solution for repeated use without any significant capacity loss. Fixed-bed column treatment of simulated waters containing heavy metals at high or trace levels was also performed. The content of heavy metals in treated effluent approached or met the WHO drinking water standard. PMID:18589978

  18. Development of high-productivity, strong cation-exchange adsorbers for protein capture by graft polymerization from membranes with different pore sizes

    PubMed Central

    Chenette, Heather C.S.; Robinson, Julie R.; Hobley, Eboni; Husson, Scott M.

    2012-01-01

    This paper describes the surface modification of macroporous membranes using ATRP (atom transfer radical polymerization) to create cation-exchange adsorbers with high protein binding capacity at high product throughput. The work is motivated by the need for a more economical and rapid capture step in downstream processing of protein therapeutics. Membranes with three reported nominal pore sizes (0.2, 0.45, 1.0 μm) were modified with poly(3-sulfopropyl methacrylate, potassium salt) tentacles, to create a high density of protein binding sites. A special formulation was used in which the monomer was protected by a crown ether to enable surface-initiated ATRP of this cationic polyelectrolyte. Success with modification was supported by chemical analysis using Fourier-transform infrared spectroscopy and indirectly by measurement of pure water flux as a function of polymerization time. Uniformity of modification within the membranes was visualized with confocal laser scanning microscopy. Static and dynamic binding capacities were measured using lysozyme protein to allow comparisons with reported performance data for commercial cation-exchange materials. Dynamic binding capacities were measured for flow rates ranging from 13 to 109 column volumes (CV)/min. Results show that this unique ATRP formulation can be used to fabricate cation-exchange membrane adsorbers with dynamic binding capacities as high as 70 mg/mL at a throughput of 100 CV/min and unprecedented productivity of 300 mg/mL/min. PMID:23175597

  19. Conductivity and photoconductivity of polymeric composites containing heteropolynuclear Cu(II)/Mn(II) complex in the presence of ionic polymethine dyes

    SciTech Connect

    Davidenko, N. A. Kokozay, V. N.; Ishchenko, A. A.; Beznishchenko, A. A.; Makhan'kova, V. G.; Spitsyna, N. G.; Lobach, A. S.; Davidenko, I. I.; Popenaka, A. N.

    2007-06-15

    Electrical and photoconductive properties of polymeric composites doped with heteropolynuclear Cu(II)/Mn(II) complex were studied in comparison with copper acetate and manganese oxalate. In the visible region, the internal photoelectric effect is enhanced by doping with organic polymethine dyes (capable of photogenerating the holes or electrons), as well as with donors or acceptors that provide carrier transport in a neutral polymeric binder. It was assumed that there are states for carrier recombination on the surface of heteropolynuclear complex particles.

  20. Vinylbenzyl quaternary ammonium-based polymeric monolith with hydrophilic interaction/strong anion exchange mixed-mode for pressurized capillary electrochromatography.

    PubMed

    Lin, Xucong; Feng, Shuhui; Jia, Wenchao; Ding, Kang; Xie, Zenghong

    2013-11-01

    A novel polymeric monolith with hydrophilic interaction and strong anion-exchange mixed-mode has been fabricated for pressurized capillary electrochromatography by an in situ copolymerization of vinylbenzyl trimethylammonium chloride (VBTA) and bisphenol A glycerolate dimethacrylate (BisGMA). The optimization of the polymerization mixture composition has been investigated, and column characteristics in terms of mechanical stability, permeability and reproducibility have been studied in detail. Linear responses between back pressure and flow rate have been achieved in different solvents. The absolute value of swelling propensity (SP) factor for poly(VBTA-co-BisGMA) monolith is 0.41, and the degree of permeability drop from pure ACN to water is about 45%. An acceptable mechanical stability of the column is obtained. The suitable reproducibility is also measured with the RSD for day-to-day (n=3) of retention time and column efficiency less than 3.3%, and the RSD for batch-to-batch (n=3) less than 5.3%, respectively. Under the optimum conditions, the mixed-mode of hydrophilic interaction and strong anion-exchange has been carried out, and efficient electrochromatography profiling of various polar compounds including neutral phenols, negatively charged benzoic acids and positively charged nucleic acid bases and nucleosides are achieved, respectively. PMID:24125728

  1. Modeling cesium retention onto Na-, K- and Ca-smectite: Effects of ionic strength, exchange and competing cations on the determination of selectivity coefficients

    NASA Astrophysics Data System (ADS)

    Missana, Tiziana; Benedicto, Ana; García-Gutiérrez, Miguel; Alonso, Ursula

    2014-03-01

    Cesium (137Cs) retention onto three homoionic smectites (Na-, K- and Ca-smectite), obtained from natural Spanish FEBEX bentonite, was studied. Special emphasis was given to the analysis of non-linear sorption behaviour and the dependence of selectivity on the ionic strength. A very large set of experimental sorption data was generated from sorption tests under a wide range of pHs (2-11), ionic strengths (10-3 to 100 M), and radionuclide concentrations (10-10 to 10-3 M). The aqueous phase, in contact with the clay, was analysed to quantify the effects of the presence of trace aqueous ions on Cs retention. For all the exchanged clays, Cs sorption was non-linear and a two-site exchange model approach was adopted to interpret and model sorption data. Highly selective sites for Cs sorption (Type 1 sites, T1), resembling those present in micaceous materials, with very low capacity but controlling uptake of Cs at low concentration, were observed. The logarithm value of selectivity coefficients determined for Cs+ in respect to Na+, K+ and Ca2+ in these sites is: LogNaCsK(T1)=7.59±0.15,LogKCsK(T1)=5.15±0.15 and LogCaCsK(T1)=14.41±0.17, respectively. The exchange sites at the surface of smectite sheets (planar sites), with a capacity approximately equivalent to the cation exchange capacity (CEC) of the clay, constitute the second type of sorption sites (Type 2 sites, T2). The logarithm of the selectivity coefficients determined for Cs+ with respect to Na+, K+ and Ca2+ is: LogNaCsK(T2)=1.68±0.15,LogKCsK(T2)=1.16±0.15LogCaCsK(T2)=3.02± 0.15, respectively. The analysis of the dependence of sorption values on the ionic strength clearly indicated that for a correct interpretation of data, competition effects of trace ions in solution must be always accounted for. Data obtained in this work and performed analyses are basic to explain the behaviour of raw FEBEX bentonite, and other smectite-based clay materials, under more complex experimental conditions.

  2. Incorporation of multi-walled carbon nanotubes in microspheres used as anion exchange resin via suspension polymerization

    NASA Astrophysics Data System (ADS)

    Fathy, Mahmoud; Abdel Moghny, Th.; Awadallah, Ahmed E.; El-Bellihi, Abdel-Hameed A.-A.

    2014-06-01

    Amination of vinylbenzyl chloride-divinylbenzene (VBC-DVB) copolymers is an effective method for preparation of anion-exchange resins. Conventionally, the starting polymer is produced by chloromethylation of a styrene-divinylbenzene copolymer that utilizes chloromethyl methyl ether, a known carcinogen. An alterative approach is to copolymerize vinylbenzyl chloride with divinylbenzene to generate the necessary VBC-DVB. This method provides precise control over the density of the ion-exchange groups. The regiochemistry of the vinylbenzyl chloride methods was realized using solvent-ion exchange groups. These resulting anion-exchange polymers were characterized by a variety of techniques such as analytical titrations, transform infrared spectroscopy and thermal gravimetric analysis. Testing of these copolymers for breakthrough was performed. The results indicate that these anion exchangers have a meaningful increase in thermal stability over commercial anionic exchange beads. Resins containing MWCNTs achieved anion exchange capacity value of 323.6 meq/100 g over than that of copolymer resins and that useful in water desalination or treatment.

  3. Determination of acrylamide in brewed coffee and coffee powder using polymeric ionic liquid-based sorbent coatings in solid-phase microextraction coupled to gas chromatography-mass spectrometry.

    PubMed

    Cagliero, Cecilia; Ho, Tien D; Zhang, Cheng; Bicchi, Carlo; Anderson, Jared L

    2016-06-01

    This study describes a simple and rapid sampling method employing a polymeric ionic liquid (PIL) sorbent coating in direct immersion solid-phase microextraction (SPME) for the trace-level analysis of acrylamide in brewed coffee and coffee powder. The crosslinked PIL sorbent coating demonstrated superior sensitivity in the extraction of acrylamide compared to all commercially available SPME coatings. A spin coating method was developed to evenly distribute the PIL coating on the SPME support and reproducibly produce fibers with a large film thickness. Ninhydrin was employed as a quenching reagent during extraction to inhibit the production of interfering acrylamide. The PIL fiber produced a limit of quantitation for acrylamide of 10μgL(-1) and achieved comparable results to the ISO method in the analysis of six coffee powder samples. PMID:27157428

  4. White-light-exciting, layer-by-layer-assembled ZnCdHgSe quantum dots/polymerized ionic liquid hybrid film for highly sensitive photoelectrochemical immunosensing of neuron specific enolase.

    PubMed

    Yu, Xiangyang; Wang, Yanying; Chen, Xuemin; Wu, Kangbing; Chen, Danchao; Ma, Ming; Huang, Zhenjia; Wu, Wangze; Li, Chunya

    2015-04-21

    ZnCdHgSe quantum dots (QDs) functionalized with N-acetyl-l-cysteine were synthesized and characterized. Through layer-by-layer assembling, the ZnCdHgSe QDs was integrated with a polymerized 1-decyl-3-[3-pyrrole-1-yl-propyl]imidazolium tetrafluoroborate (PDPIT) ionic liquid film modified indium tin oxide (ITO) electrode to fabricated a photoelectrochemical interface for the immobilization of rabbit antihuman neuron specific enolase (anti-NSE). After being treated with glutaraldehyde vapor and bovine serum albumin successively, an anti-NSE/ZnCdHgSe QDs/PDPIT/ITO sensing platform was established. Simplely using a white-light LED as an excitation source, the immunoassay of neuron specific enolase (NSE) was achieved through monitoring the photocurrent variation. The polymerized ionic liquid film was demonstrated to be an important element to enhance the photocurrent response of ZnCdHgSe QDs. The anti-NSE/ZnCdHgSe QDs/PDPIT/ITO based immunosensor presents excellent performances in neuron specific enolase determination. The photocurrent variation before and after being interacted with NSE exhibits a good linear relationship with the logarithm of its concentration (log cNSE) in the range from 1.0 pg mL(-1) to 100 ng mL(-1). The limit of detection of this immunosensor is able to reach 0.2 pg mL(-1) (S/N = 3). The determination of NSE in clinical human sera was also demonstrated using anti-NSE/ZnCdHgSe QDs/PDPIT/ITO electrode. The results were found comparable with those obtained by using enzyme-linked immunosorbent assay method. PMID:25790014

  5. Determination of non-ionic and anionic surfactants in industrial products by separation on a weak ion-exchanger, derivatization and liquid chromatography.

    PubMed

    Ripoll-Seguer, L; Beneito-Cambra, M; Herrero-Martínez, J M; Simó-Alfonso, E F; Ramis-Ramos, G

    2013-12-13

    A method for the determination of priority surfactants, including fatty alcohol ethoxylates (FAE), alkylether sulfates (AES) and linear alkylbenzene sulfonates (LAS) is described. The samples were diluted with 50% methanol at pH 4 prior to solid-phase extraction on a weak anionic exchanger (WAX). The AES and LAS surfactant classes were retained, whereas the non-ionic components, including most FAE oligomers were eluted. After washing the WAX cartridge to remove cations, the remaining hydrophobic FAE oligomers were eluted using hot 80% methanol at pH 4 (at ca. 50°C). These two eluates were combined to constitute the non-ionic fraction. Then, AES and LAS were eluted using 80% MeOH with 3M NH3 followed by 95% methanol with 0.75M NH3. The two eluates obtained in basic media were combined to constitute the anionic fraction. The solvents were evaporated, the residues were dissolved in 1,4-dioxane, and esterification of the alcohols and transesterification of AES with phthalic anhydride was performed. Separation of the derivatized oligomers was achieved by gradient elution on a C8 column with acetonitrile/water in the presence of 0.1% acetic acid and 0.1M NaClO4. The chromatogram of the non-ionic fraction showed the peaks of the resolved FAE oligomers. The chromatogram of the anionic fraction showed the peaks of the LAS homologues well resolved from those of the AES oligomers. The method was applied to laundry and industrial cleaners, shampoos and a shower gel.

  6. Optimum ionic conductivity and diffusion coefficient of ion-exchange membranes at high methanol feed concentrations in a direct methanol fuel cell

    NASA Astrophysics Data System (ADS)

    Lee, K.; Nam, J.-D.

    In direct methanol fuel cells (DMFCs), the optimum characteristics of ion-exchange membranes are investigated at high concentrations of methanol feed up to 7 M by modifying the diffusion coefficient and the ionic conductivity of the polyelectrolyte material. A Nafion membrane is modified by the incorporation of layered double hydroxide (LDH) nanoplatelets with different Mg 2+:Al 3+ ratios. When the feed concentration of methanol is lower than 3 M, the DMFC is controlled by the ionic conductivity of the polyelectrolyte membrane because methanol cross-over is not relatively significant. When the feed concentration is high, however, the diffusion coefficient of methanol is the key factor that determines the performance of the fuel cell. This is due to a high concentration gradient of methanol across the polyelectrolyte membrane. The open-circuit voltage is increased by the decreased diffusion coefficient in LDH/Nafion nanocomposite membranes at methanol feed concentrations up to 7 M; apparently because methanol cross-over is suppressed by the incorporation of LDH. The maximum power density of the DMFC is determined by the two competing transport processes of ion conduction and methanol diffusion, especially at a relatively high methanol concentration, that can provide optimum operating conditions in the membrane.

  7. Non-ionic surfactant modified ligand exchange chromatography using copper (II) complex of N,N-dimethyl-L-phenylalanine as the chiral additive for enantioselective amino acids separation.

    PubMed

    Dimitrova, Pepa; Bart, Hans-Jörg

    2010-03-17

    The influence of non-ionic surfactants on the selectivity and retention in the ligand exchange chromatography for the enantioselective separation of racemic mixtures of the amino acids dl-methionine, dl-leucine, dl-valine and dl-tyrosine applying chiral mobile phases was investigated, whereas five different surfactants were tested as modifiers. The experiments were carried out using a commercially available non-chiral RP-C8 column and the copper (II) complex of N,N-dimethyl-l-phenylalanine as the chiral additive. Varying the surfactant concentrations the retention factors and the selectivity could be controlled and in general no negative influence on the separation (due to surfactant adsorption on the non-chiral stationary phase) occurred. Changing the temperature the van't Hoff plots were obtained and the thermodynamic parameters calculated. Temperature had influence on the selectivity for each surfactant and lowered the retention times as expected.

  8. EXCHANGE

    SciTech Connect

    Boltz, J.C.

    1992-09-01

    EXCHANGE is published monthly by the Idaho National Engineering Laboratory (INEL), a multidisciplinary facility operated for the US Department of Energy (DOE). The purpose of EXCHANGE is to inform computer users about about recent changes and innovations in both the mainframe and personal computer environments and how these changes can affect work being performed at DOE facilities.

  9. Novel amphiphilic polymeric ionic liquid-solid phase micro-extraction membrane for the preconcentration of aniline as degradation product of azo dye Orange G under sonication by liquid chromatography-tandem mass spectrometry.

    PubMed

    Cai, Mei-Qiang; Wei, Xiao-Qing; Du, Chun-Hui; Ma, Xu-Ming; Jin, Mi-Cong

    2014-07-01

    A novel amphiphilic polymeric ionic liquid membrane containing a hydrophilic bromide anion and a hydrophobic carbonyl group was synthesized in dimethylformamide (DMF) systems using the ionic liquid 1-butyl-3-vinylimidazolium bromide (BVImBr) and the methylmethacrylate (MMA) as monomers. The prepared amphiphilic ploy-methylmethacrylate-1-butyl-3-vinylimidazolium bromide (MMA-BVImBr) was characterized by a scanning electron microscope and an infrared spectrum instrument. The results of solid-phase micro-extraction membrane (SPMM) experiments showed that the adsorption capacity of membrane was about 0.76μgμg(-1) for aniline. Based on this, a sensitive method for the determination of trace aniline, as a degradation product of azo dye Orange G under sonication, was developed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The calibration curve showed a good linearity ranging from 0.5 to 10.0μgL(-1) with a correlation coefficient value of 0.9998. The limit of quantification was 0.5μgL(-1). The recoveries ranged from 90.6% to 96.1%. The intra- and inter-day relative standard deviations were less than 8.3% and 10.9%. The developed SPMM-LC-MS/MS method was used successfully for preconcentration of trace aniline produced during the sonication of Orange G solution.

  10. Multiple monolithic fiber solid-phase microextraction based on a polymeric ionic liquid with high-performance liquid chromatography for the determination of steroid sex hormones in water and urine.

    PubMed

    Liao, Keren; Mei, Meng; Li, Haonan; Huang, Xiaojia; Wu, Cuiqin

    2016-02-01

    The development of a simple and sensitive analytical approach that combines multiple monolithic fiber solid-phase microextraction with liquid desorption followed by high-performance liquid chromatography with diode array detection is proposed for the determination of trace levels of seven steroid sex hormones (estriol, 17β-estradiol, testosterone, ethinylestradiol, estrone, progesterone and mestranol) in water and urine matrices. To extract the target analytes effectively, multiple monolithic fiber solid-phase microextraction based on a polymeric ionic liquid was used to concentrate hormones. Several key extraction parameters including desorption solvent, extraction and desorption time, pH value and ionic strength in sample matrix were investigated in detail. Under the optimal experimental conditions, the limits of detection were found to be in the range of 0.027-0.12 μg/L. The linear range was 0.10-200 μg/L for 17β-estradiol, 0.25-200 μg/L estriol, ethinylestradiol and estrone, and 0.50-200 μg/L for the other hormones. Satisfactory linearities were achieved for analytes with the correlation coefficients above 0.99. Acceptable method reproducibility was achieved by evaluating the repeatability and intermediate precision with relative standard deviations of both less than 8%. The enrichment factors ranged from 54- to 74-fold. Finally, the proposed method was successfully applied to the analysis of steroid sex hormones in environmental water samples and human urines with spiking recoveries ranged from 75.6 to 116%.

  11. Preparation of a Proton-Exchange Me mbrane with -SO3H Group Based on Polyethylene and Poly(vinylidene fluoride) Film by Radiation-Induced Graft Polymerization for Proton-Exchange Fuel Cell.

    PubMed

    Kim, Sang-Kyum; Lee, Yong-Sang; Koo, Kee-Kahb; Kim, Sang-Ho; Choi, Seong-Ho

    2015-09-01

    This paper reports the preparation of a proton-exchange membrane (PEM) with sulfonic acid (-SO3H) groups based on polyethylene (PE) films and poly(vinylidene fluoride) (PVdF) films by the radiation-induced graft polymerization (RIGP) of sodium styrene sulfonate (NaSS) in the presence of the polymerizable access agents, such as acrylic acid and pyrollidone in a methanol solution. A PEM with -SO3H based on PE and PVdF films were confirmed by ATR, XPS and contact angle measurements. The water uptake (%), graft yield (%), ion-exchange content (mmol/g), and proton conductivity (S/cm), as well as the current density (mA/cm2), and power density (mW/cm) for PEM with -SO3H groups prepared by RIGP were evaluated. The PEM prepared with the -SO3H groups based on PE and PVdF films can be used as a proton-exchange fuel cell membrane. PMID:26716266

  12. Preparation of a Proton-Exchange Me mbrane with -SO3H Group Based on Polyethylene and Poly(vinylidene fluoride) Film by Radiation-Induced Graft Polymerization for Proton-Exchange Fuel Cell.

    PubMed

    Kim, Sang-Kyum; Lee, Yong-Sang; Koo, Kee-Kahb; Kim, Sang-Ho; Choi, Seong-Ho

    2015-09-01

    This paper reports the preparation of a proton-exchange membrane (PEM) with sulfonic acid (-SO3H) groups based on polyethylene (PE) films and poly(vinylidene fluoride) (PVdF) films by the radiation-induced graft polymerization (RIGP) of sodium styrene sulfonate (NaSS) in the presence of the polymerizable access agents, such as acrylic acid and pyrollidone in a methanol solution. A PEM with -SO3H based on PE and PVdF films were confirmed by ATR, XPS and contact angle measurements. The water uptake (%), graft yield (%), ion-exchange content (mmol/g), and proton conductivity (S/cm), as well as the current density (mA/cm2), and power density (mW/cm) for PEM with -SO3H groups prepared by RIGP were evaluated. The PEM prepared with the -SO3H groups based on PE and PVdF films can be used as a proton-exchange fuel cell membrane.

  13. PbSe films by ion exchange of synthetic plumbonacrite layers immersed in a selenium ionic solution

    NASA Astrophysics Data System (ADS)

    Mendívil-Reynoso, T.; Ochoa-Landín, R.; Ramírez-Rodríguez, L. P.; Gutierrez-Acosta, K.; Ramírez-Bon, R.; Castillo, S. J.

    2016-06-01

    Plumbonacrite is a lead compound with chemical formula Pb10(CO3)6(OH)6O, where several groups can be substituted by ion exchange in mild conditions. Plumbonacrite layers can be deposited by means of the chemical bath deposition technique. In this work it is studied the structural and morphological evolution of a plumbonacrite layer as a function of the immersion time in an aqueous solution containing Se-2 ions. The 1.39 μm thick plumbonacrite layer was chemically deposited on a glass substrate and immersed in an aqueous solution with Se-2 ions for 10, 20, 30 and 50 min. The as grown plumbonacrite layer as well as the immersed ones were analyzed by X-rays Diffraction, Scanning Electron Microscopy and Raman Spectroscopy measurements. The results show that the plumbonacrite layer is gradually converted to PbSe one by ion exchange process, where Se-2 ions substitute the groups of plumbonacrite.

  14. [Preparation of L-phenylalanine chiral ligand-exchange chromatographic stationary phase by atom transfer radical polymerization and resolution of racemates].

    PubMed

    Sun, Yang; Xu, Fei; Gong, Bolin

    2011-09-01

    A novel stationary phase was synthesized for chiral ligand-exchange chromatography via atom transfer radical polymerization (ATRP). Glycidyl methacrylate (GMA) was grafted onto the surface of the silica by ATRP using bromoisobutyryl bromide as an initiator, and the organic metal compound formed in the CuCl/2,2'-bipyridine(Bpy) system as a catalyst at room temperature. The chiral stationary phase was then synthesized by grafting L-phenylalanine on the surface of the silica. The stationary phase was characterized by means of elementary analysis and evaluated in detail to determine its separability. The amount of L-phenylalanine on the surface of silica was calculated to be 4.32 mg/m2. The results showed that the good enantioseparations of some DL-amino acids were obtained using ligand-exchange chromatography on the synthesized chiral stationary phase (50 degrees C) with 0.05 mol/L KH2PO4 and 0.1 mmol/L Cu(Ac)2 solution (pH 4.5) as the mobile phase at a flow rate of 1.0 mL/min and a wavelength of 223 nm. The influences of the mobile phase pH, concentration of Cu (II), and temperature of column on the resolution of DL-amino acids by ligand-exchange chromatography were investigated. The results showed that these conditions could affect the resolution of racemates. Compared with the column prepared by radical method using L-phenylalanine directly bonded onto the surface of the silica, the synthesized stationary phase showed a better separation ability, and the DL-aspartic acids and DL-asparagines could be separated at baseline.

  15. The role of metal ions in chemical evolution - Polymerization of alanine and glycine in a cation-exchanged clay environment

    NASA Technical Reports Server (NTRS)

    Lawless, J. G.; Levi, N.

    1979-01-01

    The effect of the exchangeable cation on the condensation of glycine and alanine was investigated using a series of homoionic bentonites. A cycling procedure of drying, warming and wetting was employed. Peptide bond formation was observed, and the effectiveness of metal ions to catalyze the condensation was Cu(2+) greater than Ni(2) approximately equals Zn(2+) greater than Na(+). Glycine showed 6% of the monomer incorporated into oligomers with the largest detected being the pentamer. Alanine showed less peptide bond formation (a maximum of 2%) and only the dimer was observed.

  16. Anion-exchange reactions on a robust phosphonium photopolymer for the controlled deposition of ionic gold nanoclusters.

    PubMed

    Guterman, Ryan; Hesari, Mahdi; Ragogna, Paul J; Workentin, Mark S

    2013-05-28

    UV curing (photopolymerization) is ubiquitous in many facets of industry ranging from the application of paints, pigments, and barrier coatings all the way to fiber optic cable production. To date no reports have focused on polymerizable phosphonium salts under UV irradiation, and despite this dearth of examples, they potentially offer numerous substantial advantages to traditional UV formulation components. We have generated a highly novel coating based on UV-curable trialkylacryloylphosphonium salts that allow for the fast (seconds) and straightforward preparation of ion-exchange surfaces amenable to a roll-to-roll process. We have quantified the surface charges and exploited their accessibility by employing these surfaces in an anion exchange experiment by which [Au25L18](-) (L = SCH2CH2Ph) nanocrystals can be assembled into the solid state. This unprecedented application of such surfaces offers a paradigm shift in the emerging chemistry of Au25 research where the nanocrystals remain single and intact and where the integrity of the cluster and its solution photophysical properties are resilient in the solid state. The specific loading of [Au25L18](-) on the substrates has been determined and the completely reversible loading and unloading of intact nanocrystals to and from the surface has been established. In the solid state, the assembly has an incredible mechanical resiliency, where the surface remains undamaged even when subjected to repeated Scotch tests.

  17. Matrix-compatible sorbent coatings based on structurally-tuned polymeric ionic liquids for the determination of acrylamide in brewed coffee and coffee powder using solid-phase microextraction.

    PubMed

    Cagliero, Cecilia; Nan, He; Bicchi, Carlo; Anderson, Jared L

    2016-08-12

    Nine crosslinked polymeric ionic liquid (PIL)-based SPME sorbent coatings were designed and screened in this study for the trace level determination of acrylamide in brewed coffee and coffee powder using gas chromatography-mass spectrometry (GC-MS). The structure of the ionic liquid (IL) monomer was tailored by introducing different functional groups to the cation and the nature of the IL crosslinker was designed by altering both the structure of the cation as well as counteranions. The extraction efficiency of the new PIL coatings towards acrylamide was investigated and compared to a previously reported PIL sorbent coating. All PIL fibers exhibited excellent analytical precision and linearity. The PIL fiber coating consisting of 50% 1,12-di(3-vinylbenzylbenzimidazolium)dodecane dibis[(trifluoromethyl)sulfonyl]imide as IL crosslinker in 1-vinyl-3-(10-hydroxydecyl)imidazolium bis[(trifluoromethyl)sulfonyl]imide IL monomer resulted in a limit of quantitation of 0.5μgL(-1) with in-solution SPME sampling. The hydroxyl moiety appended to the IL cation was observed to significantly increase the sensitivity of the PIL coating toward acrylamide. The quantitation of acrylamide in brewed coffee and coffee powder was performed using the different PIL-based fibers by the method of standard addition after a quenching reaction using ninhydrin to inhibit the formation of interfering acrylamide in the GC inlet, mainly by asparagine thermal degradation. Excellent repeatability with relative standard deviations below 10% were obtained on the real coffee samples and the structure of the coatings appeared intact by scanning electron microscopy after coffee sampling proving the matrix-compatibility of the PIL sorbent coatings. PMID:27423776

  18. Utilization of highly robust and selective crosslinked polymeric ionic liquid-based sorbent coatings in direct-immersion solid-phase microextraction and high-performance liquid chromatography for determining polar organic pollutants in waters.

    PubMed

    Pacheco-Fernández, Idaira; Najafi, Ali; Pino, Verónica; Anderson, Jared L; Ayala, Juan H; Afonso, Ana M

    2016-09-01

    Several crosslinked polymeric ionic liquid (PIL)-based sorbent coatings of different nature were prepared by UV polymerization onto nitinol wires. They were evaluated in a direct-immersion solid-phase microextraction (DI-SPME) method in combination with high-performance liquid chromatography (HPLC) and diode array detection (DAD). The studied PIL coatings contained either vinyl alkyl or vinylbenzyl imidazolium-based (ViCnIm- or ViBCnIm-) IL monomers with different anions, as well as different dicationic IL crosslinkers. The analytical performance of these PIL-based SPME coatings was firstly evaluated for the extraction of a group of 10 different model analytes, including hydrocarbons and phenols, while exhaustively comparing the performance with commercial SPME fibers such as polydimethylsyloxane (PDMS), polyacrylate (PA) and polydimethylsiloxane/divinylbenzene (PDMS/DVB), and using all fibers under optimized conditions. Those fibers exhibiting a high selectivity for polar compounds were selected to carry out an analytical method for a group of 5 alkylphenols, including bisphenol-A (BPA) and nonylphenol (n-NP). Under optimum conditions, average relative recoveries of 108% and inter-day precision values (3 non-consecutive days) lower than 19% were obtained for a spiked level of 10µgL(-1). Correlations coefficients for the overall method ranged between 0.990 and 0.999, and limits of detection were down to 1µgL(-1). Tap water, river water, and bottled water were analyzed to evaluate matrix effects. Comparison with the PA fiber was also performed in terms of analytical performance. Partition coefficients (logKfs) of the alkylphenols to the SPME coating varied from 1.69 to 2.45 for the most efficient PIL-based fiber, and from 1.58 to 2.30 for the PA fiber. These results agree with those obtained by the normalized calibration slopes, pointing out the affinity of these PILs-based coatings.

  19. Utilization of highly robust and selective crosslinked polymeric ionic liquid-based sorbent coatings in direct-immersion solid-phase microextraction and high-performance liquid chromatography for determining polar organic pollutants in waters.

    PubMed

    Pacheco-Fernández, Idaira; Najafi, Ali; Pino, Verónica; Anderson, Jared L; Ayala, Juan H; Afonso, Ana M

    2016-09-01

    Several crosslinked polymeric ionic liquid (PIL)-based sorbent coatings of different nature were prepared by UV polymerization onto nitinol wires. They were evaluated in a direct-immersion solid-phase microextraction (DI-SPME) method in combination with high-performance liquid chromatography (HPLC) and diode array detection (DAD). The studied PIL coatings contained either vinyl alkyl or vinylbenzyl imidazolium-based (ViCnIm- or ViBCnIm-) IL monomers with different anions, as well as different dicationic IL crosslinkers. The analytical performance of these PIL-based SPME coatings was firstly evaluated for the extraction of a group of 10 different model analytes, including hydrocarbons and phenols, while exhaustively comparing the performance with commercial SPME fibers such as polydimethylsyloxane (PDMS), polyacrylate (PA) and polydimethylsiloxane/divinylbenzene (PDMS/DVB), and using all fibers under optimized conditions. Those fibers exhibiting a high selectivity for polar compounds were selected to carry out an analytical method for a group of 5 alkylphenols, including bisphenol-A (BPA) and nonylphenol (n-NP). Under optimum conditions, average relative recoveries of 108% and inter-day precision values (3 non-consecutive days) lower than 19% were obtained for a spiked level of 10µgL(-1). Correlations coefficients for the overall method ranged between 0.990 and 0.999, and limits of detection were down to 1µgL(-1). Tap water, river water, and bottled water were analyzed to evaluate matrix effects. Comparison with the PA fiber was also performed in terms of analytical performance. Partition coefficients (logKfs) of the alkylphenols to the SPME coating varied from 1.69 to 2.45 for the most efficient PIL-based fiber, and from 1.58 to 2.30 for the PA fiber. These results agree with those obtained by the normalized calibration slopes, pointing out the affinity of these PILs-based coatings. PMID:27343586

  20. Selective preconcentration of uranyl ion by silica gel phases modified with chelating compounds as inorganic polymeric ion exchangers.

    PubMed

    Mahmoud, Mohamed E; Kenawy, Ibrahim M M; Soliman, Ezzat M; Hafez, Medhat A; Akl, Magda A A; Lashein, Rabab R A

    2008-03-01

    Four chemically modified chelating silica gel phases (I - IV) with ion exchange groups were tested for their potential capability to selectively bind, extract and preconcentrate uranyl ions (UO(2)(2+)) from different aqueous solutions as well as ore samples. Factors affecting such determination processes were studied and optimized. These included the pH of the contact solution, the mass of the silica gel phase extractant, the stirring time during the application of a static technique and the eluent concentration for desorption of the surface-bound uranyl ion and interfering anions and cations. All these factors were evaluated on the basis of determinations of the distribution coefficient value (K(d)) and the percent recovery (R%). Percent recovery values of 91% for silica phase (II) and 93% for silica phase (IV) were identified in the optimum conditions. The proposed preconcentration method was further applied to uranium ore samples as well as granite samples. The determined percentage and ppm values are in good agreement with the standard assigned ones. The structure of the synthesized silica gel phases (I - IV) and their uranyl bound complexes were identified and characterized by means of infrared analysis, thermal analysis (TGA) and potentiometric titration.

  1. Selective preconcentration of uranyl ion by silica gel phases modified with chelating compounds as inorganic polymeric ion exchangers.

    PubMed

    Mahmoud, Mohamed E; Kenawy, Ibrahim M M; Soliman, Ezzat M; Hafez, Medhat A; Akl, Magda A A; Lashein, Rabab R A

    2008-03-01

    Four chemically modified chelating silica gel phases (I - IV) with ion exchange groups were tested for their potential capability to selectively bind, extract and preconcentrate uranyl ions (UO(2)(2+)) from different aqueous solutions as well as ore samples. Factors affecting such determination processes were studied and optimized. These included the pH of the contact solution, the mass of the silica gel phase extractant, the stirring time during the application of a static technique and the eluent concentration for desorption of the surface-bound uranyl ion and interfering anions and cations. All these factors were evaluated on the basis of determinations of the distribution coefficient value (K(d)) and the percent recovery (R%). Percent recovery values of 91% for silica phase (II) and 93% for silica phase (IV) were identified in the optimum conditions. The proposed preconcentration method was further applied to uranium ore samples as well as granite samples. The determined percentage and ppm values are in good agreement with the standard assigned ones. The structure of the synthesized silica gel phases (I - IV) and their uranyl bound complexes were identified and characterized by means of infrared analysis, thermal analysis (TGA) and potentiometric titration. PMID:18332547

  2. [Separation and determination of optical isomers of phenylephrine by chiral ligand exchange capillary elcctrophoresis coupling with the promoting effect of ionic liquid].

    PubMed

    Yang, Simei; Zhang, Jiayao; Li, Fei; Hu, Xufang; Cao, Qiue

    2016-01-01

    A method for the separation and determination of optical isomers of phenylephrine was developed based on the promoting effect of non-chiral ionic liquid on chiral ligand-exchange capillary electrophoresis after the electrophoretic parameters were optimized systematically. R-phenylephrine and S-phenylephrine can be separated and determined effectively in 20 mmol/L Tris-H3PO4 buffer solution (pH 5.4) composed of 4.0 mmol/L Cu(II), 8.0 mmol/L L-proline (L-Pro) and 15 mmol/L 1-butyl-3-methylimidazolium chloride ([BMIM] Cl) with the applied voltage of 20 kV, capillary temperature of 25 °C , detection wavelength of 254 nm, and injection of 5 s at 3,447 Pa. The resolution of R- and S-phenylephrines was 1. 42. The linear ranges for the determination of R-phenylephrine and S-phenylephrine were 12. 5 - 150 mg/L and 15. 0-150 mg/L, respectively. The method has been satisfactorily used for the determination of R-phenylephrine and S-phenylephrine in the spiked blood and urine samples. The spiked recoveries in the urine sample were in the range of 93. 7% -108. 2% with the RSDs lower than 3. 18% (n= 3) , and the spiked recoveries in the blood sample were in the range of 91. 4% and 113. 1% with the RSDs lower than 4. 82% (n =3).

  3. Two solid-phase recycling method for basic ionic liquid [C4mim]Ac by macroporous resin and ion exchange resin from Schisandra chinensis fruits extract.

    PubMed

    Ma, Chun-hui; Zu, Yuan-gang; Yang, Lei; Li, Jian

    2015-01-22

    In this study, two solid-phase recycling method for basic ionic liquid (IL) 1-butyl-3-methylimidazolium acetate ([C4mim]Ac) were studied through a digestion extraction system of extracting biphenyl cyclooctene lignans from Schisandra chinensis. The RP-HPLC detection method for [C4mim]Ac was established in order to investigate the recovery efficiency of IL. The recycling method of [C4mim]Ac is divided into two steps, the first step was the separation of lignans from the IL solution containing HPD 5000 macroporous resin, the recovery efficiency and purity of [C4mim]Ac achieved were 97.8% and 67.7%, respectively. This method cannot only separate the lignans from [C4mim]Ac solution, also improve the purity of lignans, the absorption rate of lignans in [C4mim]Ac solution was found to be higher (69.2%) than that in ethanol solution (57.7%). The second step was the purification of [C4mim]Ac by the SK1B strong acid ion exchange resin, an [C4mim]Ac recovery efficiency of 55.9% and the purity higher than 90% were achieved. Additionally, [C4mim]Ac as solvent extraction of lignans from S. chinensis was optimized, the hydrolysis temperature was 90°C and the hydrolysis time was 2h. PMID:25463641

  4. Two solid-phase recycling method for basic ionic liquid [C4mim]Ac by macroporous resin and ion exchange resin from Schisandra chinensis fruits extract.

    PubMed

    Ma, Chun-hui; Zu, Yuan-gang; Yang, Lei; Li, Jian

    2015-01-22

    In this study, two solid-phase recycling method for basic ionic liquid (IL) 1-butyl-3-methylimidazolium acetate ([C4mim]Ac) were studied through a digestion extraction system of extracting biphenyl cyclooctene lignans from Schisandra chinensis. The RP-HPLC detection method for [C4mim]Ac was established in order to investigate the recovery efficiency of IL. The recycling method of [C4mim]Ac is divided into two steps, the first step was the separation of lignans from the IL solution containing HPD 5000 macroporous resin, the recovery efficiency and purity of [C4mim]Ac achieved were 97.8% and 67.7%, respectively. This method cannot only separate the lignans from [C4mim]Ac solution, also improve the purity of lignans, the absorption rate of lignans in [C4mim]Ac solution was found to be higher (69.2%) than that in ethanol solution (57.7%). The second step was the purification of [C4mim]Ac by the SK1B strong acid ion exchange resin, an [C4mim]Ac recovery efficiency of 55.9% and the purity higher than 90% were achieved. Additionally, [C4mim]Ac as solvent extraction of lignans from S. chinensis was optimized, the hydrolysis temperature was 90°C and the hydrolysis time was 2h.

  5. [Separation and determination of optical isomers of phenylephrine by chiral ligand exchange capillary elcctrophoresis coupling with the promoting effect of ionic liquid].

    PubMed

    Yang, Simei; Zhang, Jiayao; Li, Fei; Hu, Xufang; Cao, Qiue

    2016-01-01

    A method for the separation and determination of optical isomers of phenylephrine was developed based on the promoting effect of non-chiral ionic liquid on chiral ligand-exchange capillary electrophoresis after the electrophoretic parameters were optimized systematically. R-phenylephrine and S-phenylephrine can be separated and determined effectively in 20 mmol/L Tris-H3PO4 buffer solution (pH 5.4) composed of 4.0 mmol/L Cu(II), 8.0 mmol/L L-proline (L-Pro) and 15 mmol/L 1-butyl-3-methylimidazolium chloride ([BMIM] Cl) with the applied voltage of 20 kV, capillary temperature of 25 °C , detection wavelength of 254 nm, and injection of 5 s at 3,447 Pa. The resolution of R- and S-phenylephrines was 1. 42. The linear ranges for the determination of R-phenylephrine and S-phenylephrine were 12. 5 - 150 mg/L and 15. 0-150 mg/L, respectively. The method has been satisfactorily used for the determination of R-phenylephrine and S-phenylephrine in the spiked blood and urine samples. The spiked recoveries in the urine sample were in the range of 93. 7% -108. 2% with the RSDs lower than 3. 18% (n= 3) , and the spiked recoveries in the blood sample were in the range of 91. 4% and 113. 1% with the RSDs lower than 4. 82% (n =3). PMID:27319173

  6. Preparation of size-controlled magnetite nanoparticles with a graphene and polymeric ionic liquid coating for the quick, easy, cheap, effective, rugged and safe extraction of preservatives from vegetables.

    PubMed

    Chen, Yaling; Cao, Shurui; Zhang, Lei; Xi, Cunxian; Li, Xianliang; Chen, Zhiqiong; Wang, Guoming

    2016-05-27

    Size-controlled magnetite nanoparticles (Fe3O4) with 200-1000nm were synthesized by co-precipitation method. Then Fe3O4@SiO2@G@PIL was synthesized and used as modified QuEChERS adsorbent for the determination of preservatives in vegetables. The size of about 200nm of Fe3O4 in Fe3O4@SiO2@G@PIL was selected as optimum size to clean-up. It not only exerted the nanometer features of magnetic nanoparticles, but also displayed the large specific surface area of graphene (G) and the solvent effects of polymeric ionic liquids (PILs). Various experimental parameters have been investigated. Under the optimized conditions, a simple, rapid and effective method for the determination of 20 preservatives residues in vegetables was established by modified QuEChERS to gas chromatography/mass spectrometry (GC-MS) analysis. The good linearity with correlation coefficients (R(2)) of 0.9972-0.9999 was obtained over the range of 0.02-2.00mg/L for 20 preservatives. The detection limits of the proposed method for 20 preservatives ranged from 0.82 to 6.64μg/kg. The adsorbent was successfully applied for extraction and determination of preservatives in vegetable samples, which thus was time-saving with keeping good clean-up performance. PMID:27109197

  7. Preparation of size-controlled magnetite nanoparticles with a graphene and polymeric ionic liquid coating for the quick, easy, cheap, effective, rugged and safe extraction of preservatives from vegetables.

    PubMed

    Chen, Yaling; Cao, Shurui; Zhang, Lei; Xi, Cunxian; Li, Xianliang; Chen, Zhiqiong; Wang, Guoming

    2016-05-27

    Size-controlled magnetite nanoparticles (Fe3O4) with 200-1000nm were synthesized by co-precipitation method. Then Fe3O4@SiO2@G@PIL was synthesized and used as modified QuEChERS adsorbent for the determination of preservatives in vegetables. The size of about 200nm of Fe3O4 in Fe3O4@SiO2@G@PIL was selected as optimum size to clean-up. It not only exerted the nanometer features of magnetic nanoparticles, but also displayed the large specific surface area of graphene (G) and the solvent effects of polymeric ionic liquids (PILs). Various experimental parameters have been investigated. Under the optimized conditions, a simple, rapid and effective method for the determination of 20 preservatives residues in vegetables was established by modified QuEChERS to gas chromatography/mass spectrometry (GC-MS) analysis. The good linearity with correlation coefficients (R(2)) of 0.9972-0.9999 was obtained over the range of 0.02-2.00mg/L for 20 preservatives. The detection limits of the proposed method for 20 preservatives ranged from 0.82 to 6.64μg/kg. The adsorbent was successfully applied for extraction and determination of preservatives in vegetable samples, which thus was time-saving with keeping good clean-up performance.

  8. Ionic selectivity of nystatin A1 confined in nanoporous track-etched polymer membrane.

    PubMed

    Balme, Sébastien; Thiele, Daniela; Kraszewski, Sebastian; Picaud, Fabien; Janot, Jean-Marc; Déjardin, Philippe

    2014-09-01

    The hybrid biological/polymeric solid-state nanopore membrane offers several opportunities to combine the advantage of biological channel (selectivity) and material (robustness). Based on this technology, the challenge is to obtain selective ionic exchange membranes, with no energy intake. The direct insertion of an ionic channel inside a nanopore should be a promise solution. Here, the authors report a hybrid nanopore based on nystatin A1 confinement in commercial nanopore membrane. Ionic transport and selectivity studies show that the hybrid nanopores exhibit mainly an anionic behaviour, on the contrary to biological conditions. However, the order of magnitude between the different ratios of permeation of several cationic species is retained even if the blocking of divalent cation is not totally proved.

  9. An Alternative to the Ionic Model

    ERIC Educational Resources Information Center

    Sanderson, R. T.

    1975-01-01

    Describes the "coordinated polymeric model," which yields more accurate energy calculations than the "ionic model" for compounds which exhibit considerable covalency. The dichotomy between ionic and covalent bonding is thus largely broken down for solids which are nonmolecular in the crystalline state. (MLH)

  10. Polymeric microspheres

    DOEpatents

    Walt, David R.; Mandal, Tarun K.; Fleming, Michael S.

    2004-04-13

    The invention features core-shell microsphere compositions, hollow polymeric microspheres, and methods for making the microspheres. The microspheres are characterized as having a polymeric shell with consistent shell thickness.

  11. Polymeric ionic liquid modified graphene oxide-grafted silica for solid-phase extraction to analyze the excretion-dynamics of flavonoids in urine by Box-Behnken statistical design.

    PubMed

    Hou, Xiudan; Liu, Shujuan; Zhou, Panpan; Li, Jin; Liu, Xia; Wang, Licheng; Guo, Yong

    2016-07-22

    A solid-phase extraction method for the efficient analysis of the excretion-dynamics of flavonoids in urine was established and described. In this work, in situ surface radical chain-transfer polymerization and in situ anion exchange were utilized to tune the extraction performance of poly(1-vinyl-3-hexylimidazolium bromide)-graphene oxide-grafted silica (poly(VHIm(+)Br(-))@GO@Sil). Graphene oxide (GO) was first coated onto the silica using a layer-by-layer fabrication method, and then the anion of poly(VHIm(+)Br(-))@GO@Sil was changed into hexafluorophosphate (PF6(-)) by in situ anion exchange. The interaction energies between two PILs and four flavonoids were calculated with the Gaussian09 suite of programs. A Box-Behnken design was used for the optimization of four greatly influential parameters after single-factor experiments to obtain more accurate and precise results. Coupled to high performance liquid chromatography, the poly(VHIm(+)PF6(-))@GO@Sil method showed acceptable extraction recoveries for the four flavonoids, with limits of detection in the range of 0.1-0.5μgL(-1), and wide linear ranges with correlation coefficients (R) ranging from 0.9935 to 0.9987. Under the optimum conditions, the proposed method was applied to analyze the urines collected from a healthy volunteer. The excretion amount-time profiles revealed that 4-15h was the main excretion time for the detected flavonoids. The results indicated that the newly developed method offered the advantages of being feasible, green and cost-effective, and could be successfully applied to the extraction and enrichment of flavonoids in human body systems allowing the study of the metabolic kinetics.

  12. Polymeric ionic liquid modified graphene oxide-grafted silica for solid-phase extraction to analyze the excretion-dynamics of flavonoids in urine by Box-Behnken statistical design.

    PubMed

    Hou, Xiudan; Liu, Shujuan; Zhou, Panpan; Li, Jin; Liu, Xia; Wang, Licheng; Guo, Yong

    2016-07-22

    A solid-phase extraction method for the efficient analysis of the excretion-dynamics of flavonoids in urine was established and described. In this work, in situ surface radical chain-transfer polymerization and in situ anion exchange were utilized to tune the extraction performance of poly(1-vinyl-3-hexylimidazolium bromide)-graphene oxide-grafted silica (poly(VHIm(+)Br(-))@GO@Sil). Graphene oxide (GO) was first coated onto the silica using a layer-by-layer fabrication method, and then the anion of poly(VHIm(+)Br(-))@GO@Sil was changed into hexafluorophosphate (PF6(-)) by in situ anion exchange. The interaction energies between two PILs and four flavonoids were calculated with the Gaussian09 suite of programs. A Box-Behnken design was used for the optimization of four greatly influential parameters after single-factor experiments to obtain more accurate and precise results. Coupled to high performance liquid chromatography, the poly(VHIm(+)PF6(-))@GO@Sil method showed acceptable extraction recoveries for the four flavonoids, with limits of detection in the range of 0.1-0.5μgL(-1), and wide linear ranges with correlation coefficients (R) ranging from 0.9935 to 0.9987. Under the optimum conditions, the proposed method was applied to analyze the urines collected from a healthy volunteer. The excretion amount-time profiles revealed that 4-15h was the main excretion time for the detected flavonoids. The results indicated that the newly developed method offered the advantages of being feasible, green and cost-effective, and could be successfully applied to the extraction and enrichment of flavonoids in human body systems allowing the study of the metabolic kinetics. PMID:27295963

  13. Central metal ion exchange in a coordination polymer based on lanthanide ions and di(2-ethylhexyl)phosphoric acid: exchange rate and tunable affinity.

    PubMed

    Tasaki-Handa, Yuiko; Abe, Yukie; Ooi, Kenta; Tanaka, Mikiya; Wakisaka, Akihiro

    2014-01-01

    In this paper the exchange of lanthanide(III) ions (Ln(3+)) between a solution and a coordination polymer (CP) of di(2-ethylhexyl)phosphoric acid (Hdehp), [Ln(dehp)3], is studied. Kinetic and selectivity studies suggest that a polymeric network of [Ln(dehp)3] has different characteristics than the corresponding monomeric complex. The reaction rate is remarkably slow and requires over 600 h to reach in nearly equilibrium, and this can be explained by the polymeric crystalline structure and high valency of Ln(3+). The affinity of the exchange reaction reaches a maximum with the Ln(3+) possessing an ionic radius 7% smaller than that of the central Ln(3+), therefore, the affinity of the [Ln(dehp)3] is tunable based on the choice of the central metal ion. Such unique affinity, which differs from the monomeric complex, can be explained by two factors: the coordination preference and steric strain caused by the polymeric structure. The latter likely becomes predominant for Ln(3+) exchange when the ionic radius of the ion in solution is smaller than the original Ln(3+) by more than 7%. Structural studies suggest that the incoming Ln(3+) forms a new phase though an exchange reaction, and this could plausibly cause the structural strain.

  14. Biosynthesis of immunoglobulin A (IgA) and immunoglobulin M (IgM). Requirement for J chain and a disulphide-exchanging enzyme for polymerization

    PubMed Central

    Corte, E. Della; Parkhouse, R. M. E.

    1973-01-01

    Mouse myeloma cells secreting 19S IgM (immunoglobulin M) (MOPC 104E and TEPC 183) or monomer and polymer IgA (immunoglobulin A) (MOPC 315) were incubated with radioactive leucine and the intracellular and secreted immunoglobulins and immunoglobulin subunits were prepared by preparative sucrose-density-gradient centrifugation. Samples were reduced in the presence or absence of isolated J chain, passed over Sephadex G-25 and then incubated at 37°C for 30min with or without a source of disulphide-interchange enzyme. The extent of reassembly of reduced subunits was then evaluated by electrophoresis in polyacrylamide gels. Provided that J chain and the disulphide-interchange enzyme were supplied, both IgM and IgA could be assembled from their respective subunits, obtained by reductive cleavage of polymeric forms. Under similar conditions, assembly of polymeric forms from intracellular or secreted 7S monomer subunits also occurred. Under these conditions polymerization was total, there being no residue of the monomeric form. Reassembly did not occur in the absence of either J chain or the enzyme. All of the J chain released from IgM by reductive cleavage was incorporated back into the reassembled polymer. The J chain is therefore likely to be an essential structural requirement for polymeric immunoglobulins. A variety of controls ruled out non-specific interactions, and further suggested that the amino acid sequence of polypeptide chains determines the specificity of polymerization. The fact that intracellular IgA and IgM monomer subunits known to be deficient in galactose and fucose can be completely polymerized suggests that the addition of carbohydrate does not control polymerization. ImagesFig. 7. PMID:4205352

  15. Membrane separation of ionic liquid solutions

    SciTech Connect

    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.

  16. Ionic Liquid Crystals: Versatile Materials.

    PubMed

    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.

  17. Ionic Blocks

    ERIC Educational Resources Information Center

    Sevcik, Richard S.; Gamble, Rex; Martinez, Elizabet; Schultz, Linda D.; Alexander, Susan V.

    2008-01-01

    "Ionic Blocks" is a teaching tool designed to help middle school students visualize the concepts of ions, ionic compounds, and stoichiometry. It can also assist high school students in reviewing their subject mastery. Three dimensional blocks are used to represent cations and anions, with color indicating charge (positive or negative) and size…

  18. [Molecular/polymeric magnetism

    SciTech Connect

    Not Available

    1993-01-01

    New materials were synthesized to test the generality of magnetism in molecular/polymeric systems. The first room temperature molecular based magnet V(TCNE)[sub x][center dot]y(solvent) (1) is disclosed. The ferromagnetic and related transitions were studied in decamethylferrocenium tetracyanoethanide (TCNE), (1), and related materials. Our and others' models were tested for ferromagnetic and antiferromagnetic exchange between local sites; models for control of [Tc] were also tested.

  19. Simultaneous enhancements of conductivity and stability for anion exchange membranes (AEMs) through precise structure design.

    PubMed

    Ran, Jin; Wu, Liang; Wei, Bing; Chen, Yaoyao; Xu, Tongwen

    2014-09-26

    Polymeric materials as anion exchange membranes (AEMs) play an essential role in the field of energy and environment. The achievement of high performance AEMs by the precise manipulation of macromolecular architecture remains a daunting challenge. Herein, we firstly report a novel rod-coil graft copolymer AEM, possessing rigid hydrophobic main chains and soft hydrophilic graft chains. The low graft density, which can alleviate the adverse influences of ionic graft chains on the main chains, was obtained by using the living polymerization technique. Consequently, the grafted ionic groups which result in the degradation of polymer backbone was decreased to a small degree. Moreover, the relatively long graft chains induced the nanophase separation between the hydrophobic polymer chains and hydrophilic graft chains, which creates a convenient pathway for high hydroxide ion mobility. Such an accurate molecular design simultaneously improves the hydroxide ion conductivity and alkaline stability as well as dimensional stability.

  20. Preparation of Poly(ionic liquid) Hollow Particles with Switchable Permeability.

    PubMed

    Nakamura, Ryuma; Tokuda, Masayoshi; Suzuki, Toyoko; Minami, Hideto

    2016-03-15

    Poly(ionic liquid) (PIL) particles with a single-hollow structure are prepared by suspension polymerization from monomer droplets consisting of the hydrophobic ionic liquid monomer [2-(methacryloyloxy)ethyl]trimethylammonium bis(trifluoromethanesulfonyl)amide, ethylene glycol dimethacrylate, and n-butyl acetate containing dissolved poly(n-butyl methacrylate). The obtained PIL hollow particles' shells can be changed from hydrophobic to hydrophilic by anion exchange using a LiBr/ethanol solution. In the case of hydrophilic PIL hollow particles, the water-soluble fluorescent materials can penetrate into the hollow structure, whereas in the case of hydrophobic PIL hollow particles, penetration of the fluorescent materials is restricted. In addition, the encapsulated water-soluble materials can be preserved into the hollow part by changing the shell property of the PIL particle encapsulated with the water-soluble materials from hydrophilic to hydrophobic. PMID:26908213

  1. High temperature structural, polymeric foams from high internal emulsion polymerization

    SciTech Connect

    Hoisington, M.A.; Duke, J.R.; Apen, P.G.

    1996-02-01

    In 1982, a high internal phase emulsion (HIPE) polymerization process to manufacture microcellular, polymeric foam systems was patented by Unilever. This patent discloses a polymerization process that occurs in a water-in-oil emulsion in which the water represents at least 76% of the emulsion by volume. The oil phase consists of vinyl monomers such as styrene and acrylates that are crosslinked by divinyl monomers during polymerization. After polymerization and drying to remove the water phase, the result is a crosslinked polymer foam with an open cell microstructure that is homogeneous throughout in terms of morphology, density, and mechanical properties. Since 1982, numerous patents have examined various HIPE polymerized foam processing techniques and applications that include absorbents for body fluids, cleaning materials, and ion exchange systems. All the published HIPE polymerized foams have concentrated on materials for low temperature applications. Copolymerization of styrene with maleic anhydride and N-substituted maleimides to produce heat resistant thermoplastics has been studied extensively. These investigations have shown that styrene will free radically copolymerize with N-substituted maleimides to create an alternating thermoplastic copolymer with a Tg of approximately 200{degrees}C. However, there are many difficulties in attempting the maleimide styrene copolymerization in a HIPE such as lower polymerization temperatures, maleimide solubility difficulties in both styrene and water, and difficulty obtaining a stable HIPE with a styrene/maleimide oil phase. This work describes the preparation of copolymer foams from N-ethylmaleimide and Bis(3-ethyl-5-methyl-4-maleimide-phenyl)methane with styrene based monomers and crosslinking agents.

  2. Ionic liquid polyoxometalates as light emitting materials

    SciTech Connect

    Ortiz-acosta, Denisse; Del Sesto, Rico E; Scott, Brian; Bennett, Bryan L; Purdy, Geraldine M; Muenchausen, Ross E; Mc Kigney, Edward; Gilbertson, Robert

    2008-01-01

    The low melting point, negligible vapor pressure, good solubility, and thermal and chemical stability make ionic liquids useful materials for a wide variety of applications. Polyoxometalates are early transition metal oxygen clusters that can be synthesized in many different sizes and with a variety of heterometals. The most attractive feature of POMs is that their physical properties, in particular electrical, magnetic, and optical properties, can be easily modified following known procedures. It has been shown that POMs can exhibit cooperative properties, as superconductivity and energy transfer. POM ionic liquids can be obtained by selecting the appropliate cation. Different alkyl ammonium and alkyl phosphonium salts are being used to produce new POM ionic liquids together with organic or inorganic luminescent centers to design light emitting materials. Ammonium and phosphonium cations with activated, polymerizable groups are being used to further polymerize the ionic liquid into transparent, solid materials with high metal density.

  3. Host-guest chemistry of a water-soluble pillar[5]arene: evidence for an ionic-exchange recognition process and different complexation modes.

    PubMed

    Gómez, Borja; Francisco, Vitor; Fernández-Nieto, Fernando; Garcia-Rio, Luis; Martín-Pastor, M; Paleo, M Rita; Sardina, F Javier

    2014-09-15

    The complexation of an anionic guest by a cationic water-soluble pillararene is reported. Isothermal titration calorimetry (ITC), (1)H NMR, (1)H and (19)F DOSY, and STD NMR experiments were performed to characterize the complex formed under aqueous neutral conditions. The results of ITC and (1)H NMR analyses showed the inclusion of the guest inside the cavity of the pillar[5]arene, with the binding constant and thermodynamic parameters influenced by the counter ion of the macrocycle. NMR diffusion experiments showed that although a fraction of the counter ions are expelled from the host cavity by exchange with the guest, a complex with both counter ions and the guest inside the pillararene is formed. The results also showed that at higher concentrations of guest in solution, in addition to the inclusion of one guest molecule in the cavity, the pillararene can also form an external complex with a second guest molecule.

  4. Dependence of purple membrane bump curvature on pH and ionic strength analyzed using atomic force microscopy combined with solvent exchange.

    PubMed

    Yokoyama, Yasunori; Yamada, Kosuke; Higashi, Yosuke; Ozaki, Satoshi; Wang, Haorang; Koito, Naoki; Watanabe, Naoya; Sonoyama, Masashi; Mitaku, Shigeki

    2014-08-01

    Purple membrane (PM), which is a membrane patch formed by the self-assembly of the membrane protein bacteriorhodopsin (bR) with archaeal lipids, is a good subject for studying the mechanism for the supramolecular structural formation of membrane proteins. Several studies have suggested that PM is not simply planar but that it has a curvature. Atomic force microscopy (AFM) studies also indicate the presence of dome-like structures (bumps) on the cytoplasmic surface of PM. PM must have a curvature to form the bump structures; therefore, bump formations will be related to a mechanism for supramolecular structural formation via self-assembly. To elucidate the effect of an asymmetric distribution of charged residues between two aqueous domains on the bump curvature, AFM topography of identical PM sheets were examined with variation of the solvent ionic strength and pH using a newly constructed solvent circulation system. The radius and height distributions of the bumps on the identical PM sheets indicated a linear correlation. The bump curvature, which was simply estimated by the slope of the distribution, became smaller with increasing KCl concentration, which suggests that tension at the cytoplasmic surface caused by electrostatic repulsive force between negatively charged amino acid residues becomes weaker by the electrostatic shielding effect. AFM observations revealed that the bump curvature remained even at high KCl concentration where the Debye length is within a few Angstroms; therefore, the contribution of the intrinsic difference between the domain sizes of bR between two sides was confirmed. Interestingly, the bump curvature was significantly increased by the addition of CaCl2 and then decreased with a similar dependency to KCl at higher CaCl2 concentration. The effect of pH on the bump curvature was also examined, where the curvature increased and reached a maximum at pH 9, while it decreased above pH 10, at which point the two-dimensional crystalline

  5. Rational design on controlled release ion-exchange polymeric microspheres and polymer-lipid hybrid nanoparticles for the delivery of water-soluble drugs through a multidisciplinary approach

    NASA Astrophysics Data System (ADS)

    Li, Yongqiang

    Sulfopropyl dextran sulfate (SP-DS) microspheres and polymer-lipid hybrid nanoparticles (PLN) for the delivery of water-soluble anticancer drugs and P-glycoprotein inhibitors were developed by our group recently and demonstrated effectiveness in local chemotherapy. To optimize the delivery performance of these particulate systems, particularly PLN, an integrated multidisciplinary approach was developed, based on an in-depth understanding of drug-excipient interactions, internal structure, drug loading and release mechanisms, and application of advanced modeling/optimization techniques. An artificial neural networks (ANN) simulator capable of formulation optimization and drug release prediction was developed. In vitro drug release kinetics of SP-DS microspheres, with various drug loading and in different release media, were predicted by ANN. The effects of independent variables on drug release were evaluated. Good modeling performance suggested that ANN is a useful tool to predict drug release from ion-exchange microspheres. To further improve the performance of PLN, drug-polymer-lipid interactions were characterized theoretically and experimentally using verapamil hydrochloride (VRP) as a model drug and dextran sulfate sodium (DS) as a counter-ion polymer. VRP-DS complexation followed a stoichiometric rule and solid-state transformation of VRP were observed. Dodecanoic acid (DA) was identified as the lead lipid carrier material. Based upon the optimized drug-polymer-lipid interactions, PLN with high drug loading capacity (36%, w/w) and sustained release without initial burst release were achieved. VRP remained amorphous and was molecularly dispersed within PLN. H-bonding contributed to the miscibility between the VRP-DS complex and DA. Drug release from PLN was mainly controlled by diffusion and ion-exchange processes. Drug loading capacity and particle size of PLN depend on the formulation factors of the weight ratio of drug to lipid and concentrations of

  6. Chain Reaction Polymerization.

    ERIC Educational Resources Information Center

    McGrath, James E.

    1981-01-01

    The salient features and importance of chain-reaction polymerization are discussed, including such topics as the thermodynamics of polymerization, free-radical polymerization kinetics, radical polymerization processes, copolymers, and free-radical chain, anionic, cationic, coordination, and ring-opening polymerizations. (JN)

  7. A new method for separation and determination of Cr(III) and Cr(VI) in water samples by high-performance liquid chromatography based on anion exchange stationary phase of ionic liquid modified silica.

    PubMed

    Sadeghi, Susan; Moghaddam, Ali Zeraatkar

    2015-12-01

    In this work, N-methylimidazolium-chloride ionic liquid functionalized silica was prepared and used as an anion-exchange stationary phase for separation of chromium species by high-performance liquid chromatography (HPLC) with UV detection at 200 nm. The Cr(VI) as HCr2O7(-) and chelated Cr(III) with potassium hydrogen phthalate (PHP) as Cr(PHP)2 (-) was retained on the prepared column and separated using a mobile phase composed of 5% methanol in 25 mM phosphate buffer at pH 6.5. Several variables affecting the chelation/separation steps were modeled by response surface methodology (RSM) using Box-Behnken (BBD) design. The significance of the independent variables and their interactions were tested by the analysis of variances (ANOVA) with 95% confidence limit. Under the optimized conditions, the Cr(III) and Cr(VI) anionic species were well separated with a single peak for each Cr species at retention times of 2.3 and 4.3 min, respectively. The relationship between the peak area and concentration was linear in the range of 0.025-30 for Cr(III) and 0.5-20 mg L(-1) for Cr(VI) with detection limits of 0.010 and 0.210 mg L(-1) for Cr(III) and Cr(VI), respectively. The proposed method was validated by simultaneous separation and determination of the Cr species in tap and underground water samples without impose to any pretreatment.

  8. Solvent effects on the synthesis of ion-exchange membranes by radiation-induced graft polymerization of methyl. cap alpha. ,. beta. ,. beta. -trifluoroacrylate. [Freon 113

    SciTech Connect

    Omichi, H.; Okamoto, J.

    1982-06-01

    Methyl ..cap alpha..,..beta..,..beta..-trifluoroacrylate (MTFA) was grafted onto polyethylene (PE) film and fluorine-containing films to make ion-exchange membranes. In the case of PE the grafting yield was not influenced by the presence of trifluorotrichloroethane (Freon 113) in the reaction mixture, while the presence of methanol decreased the grafting yield. The transversal distribution of graft chains in the film observed by electron-probe x-ray microanalysis showed that when the grafting was carried out in the presence of Freon the amount of graft chains in the central part of PE film was much larger than that at the film surface and that the grafts obtained in the absence of Freon were located mainly at the film surface. The electric resistance of the graft PE film obtained in the presence of Freon decreased more than that of the one obtained in the absence of Freon. The weight loss of the graft films in H/sub 2/O/sub 2/ solution was negligibly small.

  9. 3D Printing of Micropatterned Anion Exchange Membranes.

    PubMed

    Seo, Jiho; Kushner, Douglas I; Hickner, Michael A

    2016-07-01

    Micropatterned anion exchange membranes (AEMs) have been 3D printed via a photoinitiated free radical polymerization and quaternization process. The photocurable formulation, consisting of diurethane dimethacrylate (DUDA), poly(ethylene glycol) diacrylate (PEGDA), dipentaerythritol penta-/hexa- acrylate, and 4-vinylbenzyl chloride (VBC), was directly cured into patterned films using a custom 3D photolithographic printing process similar to stereolithography. Measurements of water uptake, permselectivity, and ionic resistance were conducted on the quaternized poly(DUDA-co-PEGDA-co-VBC) sample series to determine their suitability as ion exchange membranes. The water uptake of the polymers increased as the ion exchange capacity (IEC) increased due to greater quaternized VBC content. Samples with IEC values between 0.98 to 1.63 mequiv/g were synthesized by varying the VBC content from 15 to 25 wt %. The water uptake was sensitive to the PEGDA content in the network resulting in water uptake values ranging from 85 to 410 wt % by varying the PEGDA fractions from 0 to 60 wt %. The permselectivity of the AEM samples decreased from 0.91 (168 wt %, 1.63 mequiv/g) to 0.85 (410 wt %, 1.63 mequiv/g) with increasing water uptake and to 0.88 (162 wt %, 0.98 mequiv/g) with decreasing IEC. Permselectivity results were relatively consistent with the general understanding of the correlation between permselectivity, water uptake, and ion content of the membrane. Lastly, it was revealed that the ionic resistance of patterned membranes was lower than that of flat membranes with the same material volume or equivalent thickness. A parallel resistance model was used to explain the influence of patterning on the overall measured ionic resistance. This model may provide a way to maximize ion exchange membrane performance by optimizing surface patterns without chemical modification to the membrane. PMID:27218137

  10. The Na+/H+ Exchanger Controls Deoxycholic Acid-Induced Apoptosis by a H+-Activated, Na+-Dependent Ionic Shift in Esophageal Cells

    PubMed Central

    Goldman, Aaron; Chen, HwuDauRw; Khan, Mohammad R.; Roesly, Heather; Hill, Kimberly A.; Shahidullah, Mohammad; Mandal, Amritlal; Delamere, Nicholas A.; Dvorak, Katerina

    2011-01-01

    Apoptosis resistance is a hallmark of cancer cells. Typically, bile acids induce apoptosis. However during gastrointestinal (GI) tumorigenesis the cancer cells develop resistance to bile acid-induced cell death. To understand how bile acids induce apoptosis resistance we first need to identify the molecular pathways that initiate apoptosis in response to bile acid exposure. In this study we examined the mechanism of deoxycholic acid (DCA)-induced apoptosis, specifically the role of Na+/H+ exchanger (NHE) and Na+ influx in esophageal cells. In vitro studies revealed that the exposure of esophageal cells (JH-EsoAd1, CP-A) to DCA (0.2 mM -0.5 mM) caused lysosomal membrane perturbation and transient cytoplasmic acidification. Fluorescence microscopy in conjunction with atomic absorption spectrophotometry demonstrated that this effect on lysosomes correlated with influx of Na+, subsequent loss of intracellular K+, an increase of Ca2+ and apoptosis. However, ethylisopropyl-amiloride (EIPA), a selective inhibitor of NHE, prevented Na+, K+ and Ca2+ changes and caspase 3/7 activation induced by DCA. Ouabain and amphotericin B, two drugs that increase intracellular Na+ levels, induced similar changes as DCA (ion imbalance, caspase3/7 activation). On the contrary, DCA-induced cell death was inhibited by medium with low a Na+ concentrations. In the same experiments, we exposed rat ileum ex-vivo to DCA with or without EIPA. Severe tissue damage and caspase-3 activation was observed after DCA treatment, but EIPA almost fully prevented this response. In summary, NHE-mediated Na+ influx is a critical step leading to DCA-induced apoptosis. Cells tolerate acidification but evade DCA-induced apoptosis if NHE is inhibited. Our data suggests that suppression of NHE by endogenous or exogenous inhibitors may lead to apoptosis resistance during GI tumorigenesis. PMID:21887327

  11. Superbase-derived protic ionic liquids

    DOEpatents

    Dai, Sheng; Luo, Huimin; Baker, Gary A.

    2013-09-03

    Protic ionic liquids having a composition of formula (A.sup.-)(BH.sup.+) wherein A.sup.- is a conjugate base of an acid HA, and BH.sup.+ is a conjugate acid of a superbase B. In particular embodiments, BH.sup.+ is selected from phosphazenium species and guanidinium species encompassed, respectively, by the general formulas: ##STR00001## The invention is also directed to films and membranes containing these protic ionic liquids, with particular application as proton exchange membranes for fuel cells.

  12. Single-molecule studies of the stringency factors and rates governing the polymerization of RecA on double-stranded DNA

    PubMed Central

    Feinstein, Efraim; Danilowicz, Claudia; Conover, Alyson; Gunaratne, Ruwan; Kleckner, Nancy; Prentiss, Mara

    2011-01-01

    RecA is a key protein in homologous recombination. During recombination, one single-stranded DNA (ssDNA) bound to site I in RecA exchanges Watson–Crick pairing with a sequence-matched ssDNA that was part of a double-stranded DNA molecule (dsDNA) bound to site II in RecA. After strand exchange, heteroduplex dsDNA is bound to site I. In vivo, direct polymerization of RecA on dsDNA through site I does not occur, though it does in vitro. The mechanisms underlying the difference have been unclear. We use single-molecule experiments to decouple the two steps involved in polymerization: nucleation and elongation. We find that elongation is governed by a fundamental clock that is insensitive to force and RecA concentration from 0.2 and 6 µM, though rates depend on ionic conditions. Thus, we can probe nucleation site stability by creating nucleation sites at high force and then measuring elongation as a function of applied force. We find that in the presence of ATP hydrolysis a minimum force is required for polymerization. The minimum force decreases with increasing RecA or ATP concentrations. We propose that force reduces the off-rate for nucleation site binding and that nucleation site stability is the stringency factor that prevents in vivo polymerization. PMID:21245047

  13. Solid State Ionics 4. Proceedings of Materials Research Society Symposium, volume 369

    NASA Astrophysics Data System (ADS)

    Nazri, Gholam-Abbas; Tarascon, Jean-Marie; Schreiber, Martha

    The proceeding of the 4th Solid State Ionics symposium is presented. This first part of the proceeding deals with the chemistry and physics of insertion materials, mostly from the viewpoint of applications as cathode materials for rechargeable lithium batteries, Ni/Cd, and Ni/metal hydride systems. Crystal chemistry and electrochemistry properties of potential oxides cathodes are discussed. The second part of the proceeding deals with sol-gel process for preparation of cathode materials for lithium batteries and other applications. Novel synthetic methods of preparation of high surface area transition metal oxides are presented. The third part deals with theory of ion conduction in solids, as well as mechanisms of ion conduction in glassy and polymeric materials. Part four deals with defect chemistry in solid electrolytes and the role of defect on ionic conductivity of ceramic electrolytes. The fifth part of the proceedings deals with polymer electrolytes and electrodes. Synthesis, characterization and performance of various polymer electrolytes and electrodes are discussed. The last part of the proceedings deals with characteristics and materials aspect of ionic devices. this includes advance solid state batteries, sensors, electrochromic devices, fuel cells, and the dynamic of ion exchange in high T(c) superconductors.

  14. A morpholinium ionic liquid for cellulose dissolution.

    PubMed

    Raut, Dilip G; Sundman, Ola; Su, Weiqing; Virtanen, Pasi; Sugano, Yasuhito; Kordas, Krisztian; Mikkola, Jyri-Pekka

    2015-10-01

    A series of substituted morpholinium ionic salts and allyl ammonium acetates were prepared. Amongst those, N-allyl-N-methylmorpholinium acetate ([AMMorp][OAc]) was found to dissolve cellulose readily without any pre-processing of native cellulose. At 120°C, [AMMorp][OAc] could dissolve 30 wt%, 28 wt% and 25 wt% of cellulose with degree of polymerization (DPn) - 789, 1644 and 2082 respectively, in 20 min. Importantly, SEC analysis indicated that no discernible changes occurred in terms of the degree of polymerization of the different celluloses after regeneration. Furthermore, when comparing the cellulose dissolution capability of these newly synthesized ionic liquids, it is evident that the combination of all three constituents - the morpholinium cation, the existence of an allyl group and choosing the acetate anion are essential for efficient cellulose dissolution. The structure and morphology of the regenerated cellulosic materials were characterized by SEM, XRD, TGA, CP/MAS (13)C NMR and FTIR, respectively. PMID:26076596

  15. A morpholinium ionic liquid for cellulose dissolution.

    PubMed

    Raut, Dilip G; Sundman, Ola; Su, Weiqing; Virtanen, Pasi; Sugano, Yasuhito; Kordas, Krisztian; Mikkola, Jyri-Pekka

    2015-10-01

    A series of substituted morpholinium ionic salts and allyl ammonium acetates were prepared. Amongst those, N-allyl-N-methylmorpholinium acetate ([AMMorp][OAc]) was found to dissolve cellulose readily without any pre-processing of native cellulose. At 120°C, [AMMorp][OAc] could dissolve 30 wt%, 28 wt% and 25 wt% of cellulose with degree of polymerization (DPn) - 789, 1644 and 2082 respectively, in 20 min. Importantly, SEC analysis indicated that no discernible changes occurred in terms of the degree of polymerization of the different celluloses after regeneration. Furthermore, when comparing the cellulose dissolution capability of these newly synthesized ionic liquids, it is evident that the combination of all three constituents - the morpholinium cation, the existence of an allyl group and choosing the acetate anion are essential for efficient cellulose dissolution. The structure and morphology of the regenerated cellulosic materials were characterized by SEM, XRD, TGA, CP/MAS (13)C NMR and FTIR, respectively.

  16. Ionic Liquids Database- (ILThermo)

    National Institute of Standards and Technology Data Gateway

    SRD 147 Ionic Liquids Database- (ILThermo) (Web, free access)   IUPAC Ionic Liquids Database, ILThermo, is a free web research tool that allows users worldwide to access an up-to-date data collection from the publications on experimental investigations of thermodynamic, and transport properties of ionic liquids as well as binary and ternary mixtures containing ionic liquids.

  17. A new method for separation and determination of Cr(III) and Cr(VI) in water samples by high-performance liquid chromatography based on anion exchange stationary phase of ionic liquid modified silica.

    PubMed

    Sadeghi, Susan; Moghaddam, Ali Zeraatkar

    2015-12-01

    In this work, N-methylimidazolium-chloride ionic liquid functionalized silica was prepared and used as an anion-exchange stationary phase for separation of chromium species by high-performance liquid chromatography (HPLC) with UV detection at 200 nm. The Cr(VI) as HCr2O7(-) and chelated Cr(III) with potassium hydrogen phthalate (PHP) as Cr(PHP)2 (-) was retained on the prepared column and separated using a mobile phase composed of 5% methanol in 25 mM phosphate buffer at pH 6.5. Several variables affecting the chelation/separation steps were modeled by response surface methodology (RSM) using Box-Behnken (BBD) design. The significance of the independent variables and their interactions were tested by the analysis of variances (ANOVA) with 95% confidence limit. Under the optimized conditions, the Cr(III) and Cr(VI) anionic species were well separated with a single peak for each Cr species at retention times of 2.3 and 4.3 min, respectively. The relationship between the peak area and concentration was linear in the range of 0.025-30 for Cr(III) and 0.5-20 mg L(-1) for Cr(VI) with detection limits of 0.010 and 0.210 mg L(-1) for Cr(III) and Cr(VI), respectively. The proposed method was validated by simultaneous separation and determination of the Cr species in tap and underground water samples without impose to any pretreatment. PMID:26526699

  18. Transport properties of highly ordered heterogeneous ion-exchange membranes.

    PubMed

    Shapiro, V; Freger, V; Linder, C; Oren, Y

    2008-08-01

    Model "ordered" heterogeneous ion exchange membranes are made with ion exchange particles heaving ion exchange capacity in the range 3 to 2.5 meq/gr (dry basis) and diameters ranging from 37 to 7 microm and 2 component room-temperature vulcanizing silicon rubber as a polymeric matrix, by applying an electric field normal to the membrane surface during preparation. These membranes were shown to have an improved ionic conductivity compared with "nonordered" membranes based on the same ion exchange content (for instance, at 10% resin content "nonordered" membranes show <10(-5) mS/cm while "ordered" membranes have conductivity of 1 mS/cm). The transport properties of ordered membranes were compared with those of nonordered membranes, through the current-voltage characteristics. Limiting currents measured for the ordered membranes were significantly higher than those of the nonordered membranes with the same resin concentration. In addition, higher limiting currents were observed in ordered membranes as the resin particles became smaller. Energy dispersion spectrometry analyses revealed that the concentration of cation exchange groups on the membrane surface was higher for ordered membrane as compared to that of nonordered membranes. This implies that the local current density for the conducting domains at the surface of the nonordered membranes is higher, leading to higher concentration polarization and, eventually, to lower average limiting current densities. The effect of ordering the particles on the membrane conductivity and transport properties was studied, and the advantages of the ordered membranes are discussed.

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

    PubMed

    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. PMID:26939357

  20. Nanostructure and Dynamics of Ionic and Non-Ionic PEO-Containing Polyureas

    NASA Astrophysics Data System (ADS)

    Chuayprakong, Sunanta; Runt, James

    2013-03-01

    A series of polyethylene oxide (PEO) - based diamines with molecular weights ranging from 250 - 6000 g/mol were polymerized in solution with 4,4'-methylene diphenyl diisocyanate (MDI). In addition, PEO soft segment diamines where modified to incorporate ionomeric species and also polymerized with MDI. The role of PEO soft segment molecular weight and the presence of ionic species on nanoscale segregation and cation conductivity were explored. The former was investigated using small-angle X-ray scattering and atomic force microscopy. Dielectric relaxation spectroscopy was used to investigate polymer and ion dynamics. Local environment and hydrogen bonding were identified by using FTIR spectroscopy.

  1. Acidic Ionic Liquids.

    PubMed

    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.

  2. Acidic Ionic Liquids.

    PubMed

    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. PMID:27175515

  3. Polymerization of perfluorobutadiene

    NASA Technical Reports Server (NTRS)

    Newman, J.; Toy, M. S.

    1970-01-01

    Diisopropyl peroxydicarbonate dissolved in liquid perfluorobutadiene is conducted in a sealed vessel at the autogenous pressure of polymerization. Reaction temperature, ratio of catalyst to monomer, and amount of agitation determine degree of polymerization and product yield.

  4. Thermally Cross-Linked Anion Exchange Membranes from Solvent Processable Isoprene Containing Ionomers

    SciTech Connect

    Tsai, Tsung-Han; Ertem, S. Piril; Maes, Ashley M.; Seifert, Soenke; Herring, Andrew M; Coughlin, E. Bryan

    2015-01-28

    Random copolymers of isoprene and 4-vinylbenzyl chloride (VBCl) with varying compositions were synthesized via nitroxide-mediated polymerization. Subsequent quaternization afforded solvent processable and cross-linkable ionomers with a wide range of ion exchange capacities (IECs). Solution cast membranes were thermally cross-linked to form anion exchange membranes. Cross-linking was achieved by taking advantage of the unsaturations on the polyisoprene backbone, without added cross-linkers. A strong correlation was found between water uptake and ion conductivity of the membranes: conductivities of the membranes with IECs beyond a critical value were found to be constant related to their high water absorption. Environmentally controlled small-angle X-ray scattering experiments revealed a correlation between the average distance between ionic clusters and the ion conductivity, indicating that a well-connected network of ion clusters is necessary for efficient ion conduction and high ion conductivity.

  5. Polymerization Reactor Engineering.

    ERIC Educational Resources Information Center

    Skaates, J. Michael

    1987-01-01

    Describes a polymerization reactor engineering course offered at Michigan Technological University which focuses on the design and operation of industrial polymerization reactors to achieve a desired degree of polymerization and molecular weight distribution. Provides a list of the course topics and assigned readings. (TW)

  6. Ionic complexation as a non-covalent approach for the design of folate anchored rifampicin Gantrez nanoparticles.

    PubMed

    Date, Praveen V; Patel, Mitesh D; Majee, Sharmila B; Samad, Abdul; Devarajan, Padma V

    2013-05-01

    The present study discloses the design of folate anchored Rifampicin-Poly methylvinylether maleic anhydride copolymer (Gantrez AN-119, Gantrez) nanoparticles (RFMGzFa) by ionic complexation. Folic acid was anchored to the preformed drug loaded nanoparticles. Folic acid was anchored in different concentration by simply varying the amount of folic acid added during preparation. RFMGzFa nanoparticles were prepared by emulsion solvent diffusion method. Gantrez AN-119 rapidly hydrolyzes in aqueous medium releasing carboxylic acid groups, to create an acidic environment. This facilitates protonation and subsequent ionic complexation of folic acid with the carboxylic groups, to enable anchoring. FTIR spectra confirmed this interaction. Infrared imaging revealed distribution of folic acid across the nanoparticle surface. Nanoparticles were obtained in the size range 350-450 nm with RFM loading of 12-14% w/w. Zeta potential confirmed colloidal stability. TEM/SEM revealed spherical morphology. RFMGzFa nanoparticles exhibited sustained release of RFM and folic acid. Folic acid showed sustained release upto 12 h, which was ion exchange mediated. A 480% enhancement in RFM uptake with RFMGzFa nanoparticles compared to 300% with RFMGz nanoparticles in-vitro, in human macrophage cell line U-937, suggested the role of folic acid in folate receptor mediated uptake. Ionic complexation represents a simple non-covalent approach for anchoring folic acid on polymeric nanoparticles of Gantrez.

  7. Synthesis of poly(ionic liquids) both in solution and on surface of silica nanoparticles as novel quasi-solid state electrolytes

    NASA Astrophysics Data System (ADS)

    Hu, Heyi

    Ionic liquids (ILs) are compounds composed of cations and anions with low melting point, usually below room temperature. ILs have some unique properties, such as high intrinsic ionic conductivity, non-volatility, non-flammability, thermal and chemical stability. Based on these properties, ILs have been considered as promising electrolyte materials. However, the sealing and fabrication of IL electrolytes remained a challenge in industry applications due to their liquid property. One way to solve this problem was to polymerize the ILs. Compared to ILs, poly(ionic liquids) (PILs) have enhanced mechanical stability, improved processability and durability. However, PILs have their own drawback, which is that once polymerized, the ionic conductivity of PILs drops a lot, usually several orders of magnitude lower than that of their monomers. To successfully apply PILs as electrolyte materials, the ionic conductivity must be improved. To have high conductivity, the PILs synthesized must have low Tgs. A series of low Tg polymer polyepichlorohydrin (polyEPCH) with molecular weight ranging from 22,000 to 76,000 were synthesized by anionic ring-opening polymerization. After quaternarization and ion exchange, a novel family of PIL electrolytes were synthesized and characterized. The PILs obtained showed not only low T g, high conductivity and good thermal stability, but also a high viscosity, which is beneficial in fabricating process. To get even higher conductivity, another low T g monomer, 2-((2-(2-(2-methoxyethoxy)ethoxy)ethoxy)methyl)oxirane (ME 3MO), was synthesized and randomly copolymerized with EPCH by cationic ring-opening polymerization. The resulting copolymer (polyEPCH-co -polyME3MO) was quaternarized and ion exchanged to form a PIL copolymer (polyGBIMTFSI-co-polyME3MO). By tuning the monomer composition, a series of PIL copolymers from polyGBIMTFSI- co-polyME3MO-8/1 to polyGBIMTFSI-co-polyME 3MO-1/4 were synthesized. All PIL copolymer samples showed higher ionic

  8. Preferential adsorption of extracellular polymeric substances from bacteria on clay minerals and iron oxide.

    PubMed

    Cao, Yuanyuan; Wei, Xing; Cai, Peng; Huang, Qiaoyun; Rong, Xinming; Liang, Wei

    2011-03-01

    The adsorption of extracellular polymeric substances (EPS) from Bacillus subtilis on montmorillonite, kaolinite and goethite was investigated as a function of pH and ionic strength using batch studies coupled with Fourier transform infrared (FTIR) spectroscopy. The adsorption isotherms of EPS on minerals conformed to the Langmuir equation. The amount of EPS-C and -N adsorbed followed the sequence of montmorillonite>goethite>kaolinite. However, EPS-P adsorption was in the order of goethite>montmorillonite>kaolinite. A marked decrease in the mass fraction of EPS adsorption on minerals was observed with the increase of final pH from 3.1 to 8.3. Calcium ion was more efficient than sodium ion in promoting EPS adsorption on minerals. At various pH values and ionic strength, the mass fraction of EPS-N was higher than those of EPS-C and -P on montmorillonite and kaolinite, while the mass fraction of EPS-P was the highest on goethite. These results suggest that proteinaceous constituents were adsorbed preferentially on montmorillonite and kaolinite, and phosphorylated macromolecules were absorbed preferentially on goethite. Adsorption of EPS on clay minerals resulted in obvious shifts of infrared absorption bands of adsorbed water molecules, showing the importance of hydrogen bonding in EPS adsorption. The highest K values in equilibrium adsorption and FTIR are consistent with ligand exchange of EPS phosphate groups for goethite surface. The information obtained is of fundamental significance for understanding interfacial reactions between microorganisms and minerals. PMID:21130614

  9. Interpenetrating polymer network ion exchange membranes and method for preparing same

    DOEpatents

    Alexandratos, Spiro D.; Danesi, Pier R.; Horwitz, E. Philip

    1989-01-01

    Interpenetrating polymer network ion exchange membranes include a microporous polymeric support film interpenetrated by an ion exchange polymer and are produced by absorbing and polymerizing monomers within the support film. The ion exchange polymer provides ion exchange ligands at the surface of and throughout the support film which have sufficient ligand mobility to extract and transport ions across the membrane.

  10. Dipyridyl-immobilized ionic liquid type hybrid silica monolith for hydrophilic interaction electrochromatography.

    PubMed

    Wang, Xiao; Zheng, Na; Huang, Yifang; Wang, Jiabin; Lin, Xucong; Xie, Zenghong

    2013-11-01

    A pyridinium-based immobilized ionic liquid type multifunctional hybrid silica monolith was prepared by the in situ polymerization of 3-chloropropyl-silica matrix and 4,4'-dipyridyl for hydrophilic interaction CEC. The obtained hybrid monolith possessed of high stable skeletal microstructures with obviously hydrophilic retention mechanism under ACN content >50% in the mobile phase. Strong and stable anodic EOF could be observed under a broad pH range from pH 3.0 to 9.0. Due to the immobilized dipyridyl groups bonded to the silica matrix surface, the resulting hydrophilic hybrid monolith possessed multiple separation interactions including hydrogen bond, π-π, and anion exchange. Excellent separations of various polar analytes including electroneutral phenols, charged acid nucleotides, and basic analytes were successfully achieved. The highest column efficiencies up to 120,000, 164,000, and 106,000 plates/m were obtained for nucleotides, nucleic acid bases, and nucleosides and nicotines, respectively. These results demonstrated that the dipyridyl-immobilized ionic liquid functionalized hybrid monolith possessed highly mechanical stability and good chromatographic performance for hydrophilic interaction electrochromatography.

  11. Electrodeposition of germanium from the ionic liquid 1-butyl-1-methylpyrrolidinium dicyanamide.

    PubMed

    Wu, Minxian; Brooks, Neil R; Schaltin, Stijn; Binnemans, Koen; Fransaer, Jan

    2013-04-14

    The electrodeposition of germanium from the ionic liquid 1-butyl-1-methylpyrrolidinium dicyanamide ([BMP][DCA]) and a mixture of [BMP][DCA] and 1-butyl-1-methylpyrrolidinium chloride ([BMP]Cl) was studied using cyclic voltammetry and using an electrochemical quartz crystal microbalance (EQCM). [GeCl4(BuIm)2] (BuIm = N-butylimidazole) was used as germanium source as it has a solubility of 0.47 M, up to 13 times the solubility of GeCl4 in [BMP][DCA]. Cyclic voltammograms show an irreversible electrochemical behavior and two reduction waves were observed. The wave at the more positive potential was assigned to the reduction of Ge(4+) to Ge(2+). The wave at the more negative potential was attributed to the formation of Ge(0). The diffusion coefficient of Ge(4+) in [BMP][DCA] containing 0.1 M [GeCl4(BuIm)2] is 1.1 × 10(-12) m(2) s(-1), and the exchange current density is 2 × 10(-4) A m(-2) at 50 °C. Polymerization of dicyanamide anions took place at the anode in the solution of [BMP][DCA]. The polymerization reaction could be avoided by using an equimolar [BMP]Cl-[BMP][DCA] mixture as electrolyte. Smooth, porous germanium films were electrodeposited on both copper and silicon substrates.

  12. Ionic liquid based multifunctional double network gel

    NASA Astrophysics Data System (ADS)

    Ahmed, Kumkum; Higashihara, Tomoya; Arafune, Hiroyuki; Kamijo, Toshio; Morinaga, Takashi; Sato, Takaya; Furukawa, Hidemitsu

    2015-04-01

    Gels are a promising class of soft and wet materials with diverse application in tissue engineering and bio-medical purpose. In order to accelerate the development of gels, it is required to synthesize multi-functional gels of high mechanical strength, ultra low surface friction and suitable elastic modulus with a variety of methods and new materials. Among many types of gel ionic gel made from ionic liquids (ILs) could be used for diverse applications in electrochemical devices and in the field of tribology. IL, a promising materials for lubrication, is a salt with a melting point lower than 100 °C. As a lubricant, ILs are characterized by an extremely low vapor pressure, high thermal stability and high ion conductivity. In this work a novel approach of making double network DN ionic gel using IL has been made utilizing photo polymerization process. A hydrophobic monomer Methyl methacrylate (MMA) has been used as a first network and a hydrophobic IL monomer, N,N-diethyl-N-(2-mthacryloylethyl)-N-methylammonium bistrifluoromethylsulfonyl)imide (DEMM-TFSI) has been used as a second network using photo initiator benzophenon and crosslinker triethylene glycol dimethacrylate (TEGDMA). The resulting DN ionic gel shows transparency, flexibility, high thermal stability, good mechanical toughness and low friction coefficient value which can be a potential candidate as a gel slider in different mechanical devices and can open a new area in the field of gel tribology.

  13. Polymerizable ionic liquid with state of the art transport properties.

    PubMed

    Jeremias, Sebastian; Kunze, Miriam; Passerini, Stefano; Schönhoff, Monika

    2013-09-12

    The physicochemical properties of diallyldimethylammonium-bis(trifluoromethanesulfonyl)imide (DADMATFSI) and its binary mixture with LiTFSI are presented herein, also showing this novel compound as a polymerizable room temperature ionic liquid with excellent transport properties for Li(+) ions. In particular, results of pulsed field gradient (PFG)-NMR diffusion experiments and impedance measurements show that DADMATFSI exhibits state of the art properties of ionic liquids. Similar ionic diffusion coefficients and a similarly high conductivity as seen in the benchmark compound N-butyl-N-methylpyrrolidinium-bis(trifluoromethanesulfonyl)imide (PYR14TFSI) are observed. In accordance, the Li transference number in the binary mixture matches the trend seen for PYR14TFSI-LiTFSI mixtures. In addition to these impressive properties as ionic liquid, DADMATFSI was polymerized by UV treatment. The polymerization is demonstrated and the ion conducting properties of the resulting gel polymer electrolyte are investigated, showing that DADMATFSI can be transformed into an ionogel and may have applications where polymerization is desirable.

  14. Application of Ionic Liquids in Pot-in-Pot Reactions.

    PubMed

    Çınar, Simge; Schulz, Michael D; Oyola-Reynoso, Stephanie; Bwambok, David K; Gathiaka, Symon M; Thuo, Martin

    2016-01-01

    Pot-in-pot reactions are designed such that two reaction media (solvents, catalysts and reagents) are isolated from each other by a polymeric membrane similar to matryoshka dolls (Russian nesting dolls). The first reaction is allowed to progress to completion before triggering the second reaction in which all necessary solvents, reactants, or catalysts are placed except for the starting reagent for the target reaction. With the appropriate trigger, in most cases unidirectional flux, the product of the first reaction is introduced to the second medium allowing a second transformation in the same glass reaction pot--albeit separated by a polymeric membrane. The basis of these reaction systems is the controlled selective flux of one reagent over the other components of the first reaction while maintaining steady-state catalyst concentration in the first "pot". The use of ionic liquids as tools to control chemical potential across the polymeric membranes making the first pot is discussed based on standard diffusion models--Fickian and Payne's models. Besides chemical potential, use of ionic liquids as delivery agent for a small amount of a solvent that slightly swells the polymeric membrane, hence increasing flux, is highlighted. This review highlights the critical role ionic liquids play in site-isolation of multiple catalyzed reactions in a standard pot-in-pot reaction. PMID:26927045

  15. Application of Ionic Liquids in Pot-in-Pot Reactions.

    PubMed

    Çınar, Simge; Schulz, Michael D; Oyola-Reynoso, Stephanie; Bwambok, David K; Gathiaka, Symon M; Thuo, Martin

    2016-01-01

    Pot-in-pot reactions are designed such that two reaction media (solvents, catalysts and reagents) are isolated from each other by a polymeric membrane similar to matryoshka dolls (Russian nesting dolls). The first reaction is allowed to progress to completion before triggering the second reaction in which all necessary solvents, reactants, or catalysts are placed except for the starting reagent for the target reaction. With the appropriate trigger, in most cases unidirectional flux, the product of the first reaction is introduced to the second medium allowing a second transformation in the same glass reaction pot--albeit separated by a polymeric membrane. The basis of these reaction systems is the controlled selective flux of one reagent over the other components of the first reaction while maintaining steady-state catalyst concentration in the first "pot". The use of ionic liquids as tools to control chemical potential across the polymeric membranes making the first pot is discussed based on standard diffusion models--Fickian and Payne's models. Besides chemical potential, use of ionic liquids as delivery agent for a small amount of a solvent that slightly swells the polymeric membrane, hence increasing flux, is highlighted. This review highlights the critical role ionic liquids play in site-isolation of multiple catalyzed reactions in a standard pot-in-pot reaction.

  16. Synthesis, characterization and applications of ionic supramolecular assemblies

    NASA Astrophysics Data System (ADS)

    Lin, Xinrong

    Supramolecular ionic assemblies not only provide alternatives to conventional polymers, but also introduce unique and interesting functions for the design of "smart" polymeric assemblies for use in a number of fields due to their programmable and reversible properties. Research in the area has led to an understanding of the connection between molecular contributions and macroscopic properties, as well as a range of applications from material processing/manufacuturing to energy transfer and storage. To this end, we have developed a library of charged building blocks based on ionic liquids to create functional supramolecular ionic assemblies. The polymeric ionic assemblies prepared from a di-phosphonium and poly (acrylic acid) were first studied and found to have the potential to be utilized as "smart" materials due to their ability to reversibly respond to stimuli such as temperature and pressure. With the interest of elucidating the molecular contributions to the bulk macroscopic material properties, six supramolecular assemblies were sequentially characterized in terms of thermal, rheological and X-ray studies. The effect of side alkyl chain was found to dramatically change the material properties. A second type of supramolecular assembly was investigated based on a poly-phosphonium ionic liquid, which was complexed with a number of carboxylic acids. The material properties were easily manipulated from a sticky fiber to a brittle solid by changing the composition of the carboxylic acid. A crosslinked supramolecular assembly combining ionic interactions and weak covalent bonds, specifically disulfide bonds, was next designed and characterized. The network properties could be switched between "on and off" using mild conditions. The polymeric ionic networks and their building block ionic liquids are also of interest as safe electrolytes in energy storage devices due to their non-flammability, non-volatility, etc. We have identified one ionic liquid with superior

  17. Separation of -amino acids using a series of zwitterionic sulfobetaine exchangers.

    PubMed

    Sonnenschein, Lukas; Seubert, Andreas

    2011-09-01

    A set of five new covalently bond sulfobetaine exchangers with inner quaternary amines and outer sulfonic acids have been prepared by attachment of a series of zwitterionic precursors to hyperporous divinylbenzene polymers using a grafting reaction. The series of zwitterionic exchangers have the same backbone and identical spacers to the polymeric backbone, as well as comparable capacities. The only difference is the chain length for one to five methylene groups between the charged functional groups. Chromatographic properties are examined by separation of α-amino acids using sodium acetate and nitric acid eluents. The separation mechanism is explored by varying eluent ionic strength and eluent pH, resulting in the conclusion that amino acids are separated due to cation exchange interactions. This is a behavior never before observed using zwitterionic exchangers. It contradicts the fact that sulfobetaine-type materials used in zwitterionic ion chromatography (ZIC) usually are well suited for anion separation and only poorly for cation separation. Contrary to anion separations using the identical set of exchangers, the materials with three and four methylene groups between the charges give the highest retention factors. Materials showing the high potential in ZIC separations of inorganic anions give low retention factors for amino acids and vice versa. PMID:21859531

  18. Step-Growth Polymerization.

    ERIC Educational Resources Information Center

    Stille, J. K.

    1981-01-01

    Following a comparison of chain-growth and step-growth polymerization, focuses on the latter process by describing requirements for high molecular weight, step-growth polymerization kinetics, synthesis and molecular weight distribution of some linear step-growth polymers, and three-dimensional network step-growth polymers. (JN)

  19. Halley's polymeric organic molecules

    NASA Technical Reports Server (NTRS)

    Huebner, W. F.; Boice, D. C.; Korth, A.

    1989-01-01

    The detection of polymeric organic compounds in the mass spectrum of Comet Halley obtained with the Positive Ion Cluster Composition analyzer on Giotto are examined. It is found that, in addition to polyoxymethylene, other polymers and complex molecules may exist in the comet. It is suggested that polymerized hydrogen cyanide may be a source for the observed CN and NH2 jets.

  20. Zwitterionic polymersomes in an ionic liquid: room temperature TEM characterization.

    PubMed

    Maddikeri, Raghavendra R; Colak, Semra; Gido, Samuel P; Tew, Gregory N

    2011-10-10

    Conventional transmission electron microscopy (TEM) was utilized to characterize vesicles formed by the spontaneous self-assembly of a novel zwitterionic block copolymer in the ionic liquid (2-hydroxyethyl)dimethylammonium methanesulfonate as well as in 0.1 M phosphate buffered saline (PBS). This block copolymer was synthesized via ring-opening metathesis polymerization (ROMP) of a norbornene-based sulfobetaine, followed by its end-functionalization with polystyrene to generate the necessary amphiphilic structure. The ionic liquid enabled the visualization of the vesicles in their swollen state by TEM, demonstrating a new method for improved characterization of polymer vesicles. PMID:21902263

  1. Polymeric Carbon Dioxide

    SciTech Connect

    Yoo, C-S.

    1999-11-02

    Synthesis of polymeric carbon dioxide has long been of interest to many chemists and materials scientists. Very recently we discovered the polymeric phase of carbon dioxide (called CO{sub 2}-V) at high pressures and temperatures. Our optical and x-ray results indicate that CO{sub 2}-V is optically non-linear, generating the second harmonic of Nd: YLF laser at 527 nm and is also likely superhard similar to cubic-boron nitride or diamond. CO{sub 2}-V is made of CO{sub 4} tetrahedra, analogous to SiO{sub 2} polymorphs, and is quenchable at ambient temperature at pressures above 1 GPa. In this paper, we describe the pressure-induced polymerization of carbon dioxide together with the stability, structure, and mechanical and optical properties of polymeric CO{sub 2}-V. We also present some implications of polymeric CO{sub 2} for high-pressure chemistry and new materials synthesis.

  2. Genetic Modification of the Penicillin G Acylase Surface To Improve Its Reversible Immobilization on Ionic Exchangers▿

    PubMed Central

    Montes, Tamara; Grazú, Valeria; López-Gallego, Fernando; Hermoso, Juan A.; García, Jose L.; Manso, Isabel; Galán, Beatriz; González, Ramón; Fernández-Lafuente, Roberto; Guisán, José M.

    2007-01-01

    A new mutant of the industrial enzyme penicillin G acylase (PGA) from Escherichia coli has been designed to improve its reversible immobilization on anionic exchangers (DEAE- or polyethyleneimine [PEI]-coated agarose) by assembling eight new glutamic residues distributed homogeneously through the enzyme surface via site-directed mutagenesis. The mutant PGA is produced and processed in vivo as is the native enzyme. Moreover, it has a similar specific activity to and shows the same pH activity profile as native PGA; however, its isoelectric point decreased from 6.4 to 4.3. Although the new enzyme is adsorbed on both supports, the adsorption was even stronger when supports were coated with PEI, allowing us to improve the enzyme stability in organic cosolvents. The use of restrictive conditions during the enzyme adsorption on anionic exchangers (pH 5 and high ionic strength) permitted us to still further increase the strength of adsorption and the enzyme stability in the presence of organic solvents, suggesting that these conditions allow the penetration of the enzyme inside the polymeric beds, thus becoming fully covered with the polymer. After the enzyme inactivation, it can be desorbed to reuse the support. The possibility to improve the immobilization properties on an enzyme by site-directed mutagenesis of its surface opens a promising new scenario for enzyme engineering. PMID:17098917

  3. Ion-exchange hollow fibers

    NASA Technical Reports Server (NTRS)

    Rembaum, A.; Yen, S. P. S.; Klein, E. (Inventor)

    1976-01-01

    An ion-exchange hollow fiber is prepared by introducing into the wall of the fiber polymerizable liquid monomers, and polymerizing the monomers therein to form solid, insoluble, crosslinked, ion-exchange resin particles which embed in the wall of the fiber. Excess particles blocking the central passage or bore of the fiber are removed by forcing liquid through the fiber. The fibers have high ion-exchange capacity, a practical wall permeability and good mechanical strength even with very thin wall dimensions. Experimental investigation of bundles of ion-exchange hollow fibers attached to a header assembly have shown the fiber to be very efficient in removing counterions from solution.

  4. Ion-exchange hollow fibers

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Yen, Shiao-Ping S. (Inventor); Klein, Elias (Inventor)

    1980-01-01

    An ion-exchange hollow fiber is prepared by introducing into the wall of the fiber polymerizable liquid monomers, and polymerizing the monomers therein to form solid, insoluble, cross-linked, ion-exchange resin particles which embed in the wall of the fiber. Excess particles blocking the central passage or bore of the fiber are removed by forcing liquid through the fiber. The fibers have high ion-exchange capacity, a practical wall permeability and good mechanical strength even with very thin wall dimensions. Experimental investigation of bundles of ion-exchange hollow fibers attached to a header assembly have shown the fiber to be very efficient in removing counterions from solution.

  5. Ion-exchange hollow fibers

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Yen, Shiao-Ping S. (Inventor); Klein, Elias (Inventor)

    1977-01-01

    An ion-exchange hollow fiber is prepared by introducing into the wall of the fiber polymerizable liquid monomers, and polymerizing the monomers therein to form solid, insoluble, cross-linked, ion-exchange resin particles which embed in the wall of the fiber. Excess particles blocking the central passage or bore of the fiber are removed by forcing liquid through the fiber. The fibers have high ion-exchange capacity, a practical wall permeability and good mechanical strength even with very thin wall dimensions. Experimental investigation of bundles of ion-exchange hollow fibers attached to a header assembly have shown the fiber to be very efficient in removing counterions from solution.

  6. [Molecular/polymeric magnetism]. Progress report

    SciTech Connect

    Not Available

    1993-03-01

    New materials were synthesized to test the generality of magnetism in molecular/polymeric systems. The first room temperature molecular based magnet V(TCNE){sub x}{center_dot}y(solvent) (1) is disclosed. The ferromagnetic and related transitions were studied in decamethylferrocenium tetracyanoethanide (TCNE), (1), and related materials. Our and others` models were tested for ferromagnetic and antiferromagnetic exchange between local sites; models for control of {Tc} were also tested.

  7. Separation of inorganic anions using a series of sulfobetaine exchangers.

    PubMed

    Sonnenschein, Lukas; Seubert, Andreas

    2011-02-25

    A set of five new sulfobetaine exchangers with inner quaternary amines and outer sulfonic acids have been prepared. A series of zwitterionic precursors was attached to highly porous divinylbenzene polymer using a grafting reaction, which allows a flexible adjustment of the degree of functionalisation. The resulting materials have identical spacers to the polymeric backbone and differ only in chain length between the charged functional groups. Capacities of the stationary phases were analysed by two different methods based on elemental analysis and the results obtained were found to correlate. The application of combustion elemental analysis proved an identical molar content of sulfur and nitrogen. The distance between the charged functional groups is varied from one to five methylene groups for a better understanding of the retention behaviour of inorganic anions on zwitterionic stationary phases. Inorganic anions were separated using sodium acetate eluents with varying ionic strength and pH and the behaviour of all columns has been compared to each other and to ZIC-HILIC and ZIC-pHILIC columns from Merck SeQuant. The exchangers with two and five methylene groups between the charges showed the highest retention factors. Polarity and accessibility of the anion exchange sites are dependent on the distance between the charged groups and the flexibility of the chains. These properties have a strong influence on anion separations. The exchanger with two methylene groups between the charged functional groups showed the biggest difference as compared to the commercially available ZIC-HILIC and ZIC-pHILIC exchangers. PMID:21251664

  8. Clickable Poly(ionic liquids): A Materials Platform for Transfection.

    PubMed

    Freyer, Jessica L; Brucks, Spencer D; Gobieski, Graham S; Russell, Sebastian T; Yozwiak, Carrie E; Sun, Mengzhen; Chen, Zhixing; Jiang, Yivan; Bandar, Jeffrey S; Stockwell, Brent R; Lambert, Tristan H; Campos, Luis M

    2016-09-26

    The potential applications of cationic poly(ionic liquids) range from medicine to energy storage, and the development of efficient synthetic strategies to target innovative cationic building blocks is an important goal. A post-polymerization click reaction is reported that provides facile access to trisaminocyclopropenium (TAC) ion-functionalized macromolecules of various architectures, which are the first class of polyelectrolytes that bear a formal charge on carbon. Quantitative conversions of polymers comprising pendant or main-chain secondary amines were observed for an array of TAC derivatives in three hours using near equimolar quantities of cyclopropenium chlorides. The resulting TAC polymers are biocompatible and efficient transfection agents. This robust, efficient, and orthogonal click reaction of an ionic liquid, which we term ClickabIL, allows straightforward screening of polymeric TAC derivatives. This platform provides a modular route to synthesize and study various properties of novel TAC-based polymers. PMID:27578602

  9. Morphology-enhanced conductivity in dry ionic liquids.

    PubMed

    Erbaş, Aykut; de la Cruz, Monica Olvera

    2016-03-01

    Ionic liquids exhibit fascinating nanoscale morphological phases and are promising materials for energy storage applications. Liquid crystalline order emerges in ionic liquids with specific chemical structures. Here, we investigate the phase behaviour and related ionic conductivities of dry ionic liquids, using extensive molecular dynamics simulations. Temperature dependence, properties of polymeric tail and excluded volume symmetry of the amphiphilic ionic liquid molecules are investigated in large scale systems with both short and long-range Coulomb interactions. Our results suggest that by adjusting stiffness and steric interactions of the amphiphilic molecules, lamellar or 3D continuous phases result in these molecular salts. The resulting phases are composed of ion rich and ion pure domains. In 3D phases, ion rich clusters form ionic channels and have significant effects on the conductive properties of the observed nano-phases. If there is no excluded-volume asymmetry along the molecules, mostly lamellar phases with anisotropic conductivities emerge. If the steric interactions become asymmetric, lamellar phases are replaced by complex 3D continuous phases. Within the temperature ranges for which morphological phases are observed, conductivities exhibit low-temperature maxima in accord with experiments on ionic liquid crystals. Stiffer molecules increase the high-conductivity interval and strengthen temperature-resistance of morphological phases. Increasing the steric interactions of cation leads to higher conductivities. Moreover, at low monomeric volume fractions and at low temperatures, cavities are observed in the nano-phases of flexible ionic liquids. We also demonstrate that, in the absence of electrostatic interactions, the morphology is distorted. Our findings inspire new design principles for room temperature ionic liquids and help explain previously-reported experimental data.

  10. Transparent and luminescent ionogels composed of Eu(3+)-coordinated ionic liquids and poly(methyl methacrylate).

    PubMed

    Zhou, Fan; Wang, Tianren; Li, Zhiqiang; Wang, Yige

    2015-12-01

    We report here on transparent and luminescent ionogels that consist of ionic ternary europium (III) complexes and the inexpensive non-toxic compound, poly(methyl methacrylate) (PMMA) and that were formed by dissolving these complexes in methacrylate (MMA) monomers followed by in situ polymerization. The resulting ionogels show a bright red emission under near-UV light irradiation. Luminescence data confirm the energy transfer from terpyridine-functionalized ionic liquid to Eu(3+) ions.

  11. Morphology-induced low temperature conductivity in ionic liquids

    NASA Astrophysics Data System (ADS)

    Erbas, Aykut; Olvera de La Cruz, Monica; Olvera de la Cruz Team

    Ionic liquids exhibit nano-scale liquid crystalline order depending on the polymeric details of salt molecules. The resulting morphology and temperature behavior are key factors in determining the room temperature conductivity of ionic liquids. Here we discuss the phase behavior and related ionic conductivities of dry ionic liquids with volume fractions close to unity by using extensive molecular dynamics simulations. Temperature dependence, effective persistence length of tails, and excluded volume symmetry of amphiphilic ionic liquid molecules are investigated in large scale systems with short and long-range electrostatics. Our results suggest that by adjusting stiffness of the amphiphilic molecules and excluded volume interactions, lamellar or interconnected 3D phases can be obtained. Resulting phases have significant effects on the conductive properties. If there is no excluded volume asymmetry along the molecules, mostly lamellar phases with anisotropic conductivities emerge. If the excluded volume interactions become asymmetric, lamellar phases are replaced by interconnected phases consist of charged groups. Within temperature ranges that morphological phases are observed, conductivities exhibit low-temperature maxima in accord with experiments of ionic liquid-based liquid Center of Bio-inspried Energy Center (CBES).

  12. Concise polymeric materials encyclopedia

    SciTech Connect

    Salamone, J.C.

    1999-01-01

    This comprehensive, accessible resource abridges the ``Polymeric Materials Encyclopedia'', presenting more than 1,100 articles and featuring contributions from more than 1,800 scientists from all over the world. The text discusses a vast array of subjects related to the: (1) synthesis, properties, and applications of polymeric materials; (2) development of modern catalysts in preparing new or modified polymers; (3) modification of existing polymers by chemical and physical processes; and (4) biologically oriented polymers.

  13. Applications of ionic liquids.

    PubMed

    Patel, Divia Dinesh; Lee, Jong-Min

    2012-06-01

    Ionic liquids have recently gained popularity in the scientific community owing to their special properties and characteristics. One of the reasons why ionic liquids have been termed "green solvents" is due to their negligible vapour pressure. Their use in electrochemical, biological and metal extraction applications is discussed. Wide research has been carried out for their use in batteries, solar panels, fuel cells, drug deliveries and biomass pretreatments. This work aims to consolidate the various findings from previous works in these areas.

  14. Applications of ionic liquids.

    PubMed

    Patel, Divia Dinesh; Lee, Jong-Min

    2012-06-01

    Ionic liquids have recently gained popularity in the scientific community owing to their special properties and characteristics. One of the reasons why ionic liquids have been termed "green solvents" is due to their negligible vapour pressure. Their use in electrochemical, biological and metal extraction applications is discussed. Wide research has been carried out for their use in batteries, solar panels, fuel cells, drug deliveries and biomass pretreatments. This work aims to consolidate the various findings from previous works in these areas. PMID:22711528

  15. Ionic homeostasis in brain conditioning

    PubMed Central

    Cuomo, Ornella; Vinciguerra, Antonio; Cerullo, Pierpaolo; Anzilotti, Serenella; Brancaccio, Paola; Bilo, Leonilda; Scorziello, Antonella; Molinaro, Pasquale; Di Renzo, Gianfranco; Pignataro, Giuseppe

    2015-01-01

    Most of the current focus on developing neuroprotective therapies is aimed at preventing neuronal death. However, these approaches have not been successful despite many years of clinical trials mainly because the numerous side effects observed in humans and absent in animals used at preclinical level. Recently, the research in this field aims to overcome this problem by developing strategies which induce, mimic, or boost endogenous protective responses and thus do not interfere with physiological neurotransmission. Preconditioning is a protective strategy in which a subliminal stimulus is applied before a subsequent harmful stimulus, thus inducing a state of tolerance in which the injury inflicted by the challenge is mitigated. Tolerance may be observed in ischemia, seizure, and infection. Since it requires protein synthesis, it confers delayed and temporary neuroprotection, taking hours to develop, with a pick at 1–3 days. A new promising approach for neuroprotection derives from post-conditioning, in which neuroprotection is achieved by a modified reperfusion subsequent to a prolonged ischemic episode. Many pathways have been proposed as plausible mechanisms to explain the neuroprotection offered by preconditioning and post-conditioning. Although the mechanisms through which these two endogenous protective strategies exert their effects are not yet fully understood, recent evidence highlights that the maintenance of ionic homeostasis plays a key role in propagating these neuroprotective phenomena. The present article will review the role of protein transporters and ionic channels involved in the control of ionic homeostasis in the neuroprotective effect of ischemic preconditioning and post-conditioning in adult brain, with particular regards to the Na+/Ca2+ exchangers (NCX), the plasma membrane Ca2+-ATPase (PMCA), the Na+/H+ exchange (NHE), the Na+/K+/2Cl− cotransport (NKCC) and the acid-sensing cation channels (ASIC). Ischemic stroke is the third leading

  16. Advancing Polymer-Supported Ionogel Electrolytes Formed via Radical Polymerization

    NASA Astrophysics Data System (ADS)

    Visentin, Adam F.

    fabricated. In addition to developing an understanding of UV-polymerized systems, a rapid 10 to 20 second, microwave-assisted polymerization method was developed as a novel means to create ionogels. These ionogels exhibited comparable mechanical response and ionic conductivity levels to those gels fabricated by the UV method. Lastly, an EDLC prototype was fabricated using a UV-polymerized ionogel formed in situ between two high-surface area carbon electrodes. The device performance metrics were comparable to commercial EDLCs, and functioned for several thousand cycles with limited loss in capacitance.

  17. Radical-Mediated Enzymatic Polymerizations.

    PubMed

    Zavada, Scott R; Battsengel, Tsatsral; Scott, Timothy F

    2016-01-01

    Polymerization reactions are commonly effected by exposing monomer formulations to some initiation stimulus such as elevated temperature, light, or a chemical reactant. Increasingly, these polymerization reactions are mediated by enzymes--catalytic proteins--owing to their reaction efficiency under mild conditions as well as their environmental friendliness. The utilization of enzymes, particularly oxidases and peroxidases, for generating radicals via reduction-oxidation mechanisms is especially common for initiating radical-mediated polymerization reactions, including vinyl chain-growth polymerization, atom transfer radical polymerization, thiol-ene step-growth polymerization, and polymerization via oxidative coupling. While enzyme-mediated polymerization is useful for the production of materials intended for subsequent use, it is especially well-suited for in situ polymerizations, where the polymer is formed in the place where it will be utilized. Such polymerizations are especially useful for biomedical adhesives and for sensing applications. PMID:26848652

  18. Radical-Mediated Enzymatic Polymerizations

    PubMed Central

    Zavada, Scott R.; Battsengel, Tsatsral; Scott, Timothy F.

    2016-01-01

    Polymerization reactions are commonly effected by exposing monomer formulations to some initiation stimulus such as elevated temperature, light, or a chemical reactant. Increasingly, these polymerization reactions are mediated by enzymes―catalytic proteins―owing to their reaction efficiency under mild conditions as well as their environmental friendliness. The utilization of enzymes, particularly oxidases and peroxidases, for generating radicals via reduction-oxidation mechanisms is especially common for initiating radical-mediated polymerization reactions, including vinyl chain-growth polymerization, atom transfer radical polymerization, thiol–ene step-growth polymerization, and polymerization via oxidative coupling. While enzyme-mediated polymerization is useful for the production of materials intended for subsequent use, it is especially well-suited for in situ polymerizations, where the polymer is formed in the place where it will be utilized. Such polymerizations are especially useful for biomedical adhesives and for sensing applications. PMID:26848652

  19. Failure Mechanisms of Hollow Fiber Supported Ionic Liquid Membranes

    PubMed Central

    Zeh, Matthew; Wickramanayake, Shan; Hopkinson, David

    2016-01-01

    Hollow fiber supported ionic liquid membranes (SILMs) were tested using the bubble point method to investigate potential failure modes, including the maximum transmembrane pressure before loss of the ionic liquid from the support. Porous hollow fiber supports were fabricated with different pore morphologies using Matrimid® and Torlon® as the polymeric material and 1-hexyl-3-methylimidalzolium bis(trifluoromethylsulfonyl)imide ([C6mim][Tf2N]) as the ionic liquid (IL) component. Hollow fiber SILMs were tested for their maximum pressure before failure, with pressure applied either from the bore side or shell side. It was found that the membranes exhibited one or more of three different modes of failure when pressurized: liquid loss (occurring at the bubble point), rupture, and collapse. PMID:27023620

  20. Polymeric salt bridges for conducting electric current in microfluidic devices

    DOEpatents

    Shepodd, Timothy J.; Tichenor, Mark S.; Artau, Alexander

    2009-11-17

    A "cast-in-place" monolithic microporous polymer salt bridge for conducting electrical current in microfluidic devices, and methods for manufacture thereof is disclosed. Polymeric salt bridges are formed in place in capillaries or microchannels. Formulations are prepared with monomer, suitable cross-linkers, solvent, and a thermal or radiation responsive initiator. The formulation is placed in a desired location and then suitable radiation such as UV light is used to polymerize the salt bridge within a desired structural location. Embodiments are provided wherein the polymeric salt bridges have sufficient porosity to allow ionic migration without bulk flow of solvents therethrough. The salt bridges form barriers that seal against fluid pressures in excess of 5000 pounds per square inch. The salt bridges can be formulated for carriage of suitable amperage at a desired voltage, and thus microfluidic devices using such salt bridges can be specifically constructed to meet selected analytical requirements.

  1. Polyanionic and polyzwitterionic azobenzene ionic liquid-functionalized silica materials and their chromatographic applications.

    PubMed

    Qiu, Hongdeng; Jiang, Shengxiang; Takafuji, Makoto; Ihara, Hirotaka

    2013-03-25

    New polyanionic and polyzwitterionic azobenzene ionic liquid-functionalized silica materials were designed based on the preparation of a new polymerizable azobenzene anionic monomer and either its cation-exchange with alkylimidazolium after grafting or the formation of an ionic liquid monomer pair before grafting onto silica. PMID:23417018

  2. Mesoporous and biocompatible surface active silica aerogel synthesis using choline formate ionic liquid.

    PubMed

    Meera, Kamal Mohamed Seeni; Sankar, Rajavelu Murali; Jaisankar, Sellamuthu N; Mandal, Asit Baran

    2011-09-01

    In this paper, we report the preparation and characterization of mesoporous and biocompatible transparent silica aerogel by the sol-gel polymerization of tetraethyl orthosilicate using ionic liquid. Choline cation based ionic liquid allows the silica framework to form in a non collapsing environment and controls the pore size of the gel. FT-IR spectra reveal the interaction of ionic liquid with surface -OH of the gel. DSC thermogram giving the evidence of confinement of ionic liquid within the silica matrix, which helps to avoid the shrinkage of the gel during the aging process. Nitrogen sorption measurements of gel prepared with ionic liquid exhibit a low surface area of 100.53 m2/g and high average pore size of 3.74 nm. MTT assay proves the biocompatibility and cell viability of the prepared gels. This new nanoporous silica material can be applied to immobilize biological molecules, which may retain their stability over a longer period.

  3. Investigation of Carbon-2 Substituted Imidazoles and Their Corresponding Ionic Liquids

    SciTech Connect

    Liao, Chen; Xiang, Zhu; Sun, Xiao-Guang; Dai, Sheng

    2011-01-01

    The functionality at the C-2 position of the imidazole ring plays a key role in defining the chemical properties of the imidazoles and their corresponding ionic liquids. Imidazoles 1 6 with different C-2 functionality were synthesized and their corresponding ionic liquids were systematically investigated. Based on their physical properties the six imidazoles can be divided into three groups. 1) The imidazoles 2 and 3 are capable of self-polymerization to form poly(ionic liquid)s, and they are characterized with a strong leaving group at the C-2 position. 2) The imidazoles 4 and 5 can form ionic liquids, but they are very sensitive to moisture. 3) The imidazoles 1 and 6 can form stable ionic liquids, and their stabilities were influenced by the electronic effects of the substituents at the C-2 position.

  4. Organocatalyzed Group Transfer Polymerization.

    PubMed

    Chen, Yougen; Kakuchi, Toyoji

    2016-08-01

    In contrast to the conventional group transfer polymerization (GTP) using a catalyst of either an anionic nucleophile or a transition-metal compound, the organocatalyzed GTP has to a great extent improved the living characteristics of the polymerization from the viewpoints of synthesizing structurally well-defined acrylic polymers and constructing defect-free polymer architectures. In this article, we describe the organocatalyzed GTP from a relatively personal perspective to provide our colleagues with a perspicuous and systematic overview on its recent progress as well as a reply to the curiosity of how excellently the organocatalysts have performed in this field. The stated perspectives of this review mainly cover five aspects, in terms of the assessment of the livingness of the polymerization, limit and scope of applicable monomers, mechanistic studies, control of the polymer structure, and a new GTP methodology involving the use of tris(pentafluorophenyl)borane and hydrosilane. PMID:27427399

  5. Polymerization of vegetable oils

    SciTech Connect

    Korus, R.A.; Mousetis, T.L.; Lloyd, L.

    1982-01-01

    The addition of antioxidants and dispersants is not sufficient to eliminate gum formation in vegetable oils. Even with relatively unsaturated oils like rapeseed the extent of unsaturation overwhelms these additives. Fuel deterioration during storage will be minimized in an anaerobic storage environment and, to a lesser extent, with a lower degree of oil unsaturation. Gum formation and carbon coking can also occur immediately preceding and during combustion. Thermal polymerization may be the dominant gum forming reaction under combustion conditions since thermal polymerization has a higher activation energy than oxidative polymerization and anaerobic conditions can occur within atomized fuel droplets. Carbon coking can be reduced with a lower degree of oil unsaturation and with better atomization of the fuel. 4 figures, 1 table.

  6. Ionic liquids in chemical engineering.

    PubMed

    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.

  7. Alkaline stable C2-substituted imidazolium-based cross-linked anion exchange membranes for alkaline fuel cell applications

    NASA Astrophysics Data System (ADS)

    Lin, Bencai; Chu, Fuqiang; Ren, Yurong; Jia, Baoping; Yuan, Ningyi; Shang, Hui; Feng, Tianying; Zhu, Yuanyuan; Ding, Jianning

    2014-11-01

    Novel C2-substituted imidazolium-based cross-linked anion exchange membranes (AEMs) are prepared via irradiation with ultraviolet light cross-linking of styrene, acrylonitrile and 1,3-diallyl-2-methyl imidazolium bromine ([DAMIm][Br]), and followed by anion exchange with hydroxide ions. [DAMIm][Br] is synthesized and used both as crosslinker and hydrophilic phase. The ionic conductivity of the AEMs increases with increasing [DAMIm][Br] content due to the hydrophilic regions and the continuous hydrophilic polymeric networks formed in the membranes. The imidazolium-based cross-linked AEMs show excellent thermal stabilities, and the membrane which containing 30% mass fraction of [DAMIm][Br] shows ionic conductivity up to 2.0 × 10-2 S cm-1 and good long-term chemical stability in 1 M KOH solution. The results of this study suggest that the C2-substituted imidazolium-based cross-linked AEMs have good perspectives for alkaline fuel cell applications.

  8. Variable Effect during Polymerization

    ERIC Educational Resources Information Center

    Lunsford, S. K.

    2005-01-01

    An experiment performing the polymerization of 3-methylthiophene(P-3MT) onto the conditions for the selective electrode to determine the catechol by using cyclic voltammetry was performed. The P-3MT formed under optimized conditions improved electrochemical reversibility, selectivity and reproducibility for the detection of the catechol.

  9. Protein specific polymeric immunomicrospheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Yen, Shiao-Ping S. (Inventor); Dreyer, William J. (Inventor)

    1980-01-01

    Small, round, bio-compatible microspheres capable of covalently bonding proteins and having a uniform diameter below about 3500 A are prepared by substantially instantaneously initiating polymerization of an aqueous emulsion containing no more than 35% total monomer including an acrylic monomer substituted with a covalently bondable group such as hydroxyl, amino or carboxyl and a minor amount of a cross-linking agent.

  10. Programmable Supramolecular Polymerizations.

    PubMed

    van der Zwaag, Daan; de Greef, Tom F A; Meijer, E W

    2015-07-13

    Living large: Rational design of self-assembly pathways has been demonstrated in supramolecular polymers. By controlling the concentration of an aggregation-competent monomer through intramolecular interactions, living supramolecular polymerization conditions were achieved. This universal approach can be used to obtain aggregates of well-defined length and narrow dispersity, and allows access to new supramolecular polymer architectures. PMID:26095705

  11. Effective integrative supramolecular polymerization.

    PubMed

    Zhang, Qiwei; Tian, He

    2014-09-26

    Exercise control: By taking advantage of self-sorting processes among host-guest components, a controlled supramolecular polymerization can be realized, as demonstrated recently with the preparation of a cucurbit[n]uril-based supramolecular polymer. This method may be used for the design of more ordered supramolecular polymers from complex and discrete components. PMID:25080388

  12. Polymerized and functionalized triglycerides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant oils are useful sustainable raw materials for the development of new chemical products. As part of our research emphasis in sustainability and green polymer chemistry, we have explored a new method for polymerizing epoxidized triglycerides with the use of fluorosulfonic acid. Depending on the ...

  13. Selective coulometric release of ions from ion selective polymeric membranes for calibration-free titrations.

    PubMed

    Bhakthavatsalam, Vishnupriya; Shvarev, Alexey; Bakker, Eric

    2006-08-01

    Coulometry belongs to one of the few known calibration-free techniques and is therefore highly attractive for chemical analysis. Titrations performed by the coulometric generation of reactants is a well-known approach in electrochemistry, but suffers from limited selectivity and is therefore not generally suited for samples of varying or unknown composition. Here, the selective coulometric release of ionic reagents from ion-selective polymeric membrane materials ordinarily used for the fabrication of ion-selective electrodes is described. The selectivity of such membranes can be tuned to a significant extent by the type and concentration of ionophore and lipophilic ion-exchanger and is today well understood. An anodic current of fixed magnitude and duration may be imposed across such a membrane to release a defined quantity of ions with high selectivity and precision. Since the applied current relates to a defined ion flux, a variety of non-redox active ions may be accurately released with this technique. In this work, the released titrant's activity was measured with a second ionophore-based ion-selective electrode and corresponded well with expected dosage levels on the basis of Faraday's law of electrolysis. Initial examples of coulometric titrations explored here include the release of calcium ions for complexometric titrations, including back titrations, and the release of barium ions to determine sulfate.

  14. Fun with Ionic Compounds

    ERIC Educational Resources Information Center

    Logerwell, Mollianne G.; Sterling, Donna R.

    2007-01-01

    Ionic bonding is a fundamental topic in high school chemistry, yet it continues to be a concept that students struggle to understand. Even if they understand atomic structure and ion formation, it can be difficult for students to visualize how ions fit together to form compounds. This article describes several engaging activities that help…

  15. Synthesis of ionic liquids

    DOEpatents

    Dai, Sheng [Knoxville, TN; Luo, Huimin [Knoxville, TN

    2008-09-09

    Ionic compounds which are liquids at room temperature are formed by the method of mixing a neutral organic liqand with the salt of a metal cation and its conjugate anion. The liquids are hydrophobic, conductive and stable and have uses as solvents and in electrochemical devices.

  16. Synthesis of ionic liquids

    DOEpatents

    Dai, Sheng; Luo, Huimin

    2011-11-01

    Ionic compounds which are liquids at room temperature are formed by the method of mixing a neutral organic ligand with the salt of a metal cation and its conjugate anion. The liquids are hydrophobic, conductive and stable and have uses as solvents and in electrochemical devices.

  17. Metal-air cell with ion exchange material

    SciTech Connect

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

    2015-08-25

    Embodiments of the invention are related to anion exchange membranes used in electrochemical metal-air cells in which the membranes function as the electrolyte material, or are used in conjunction with electrolytes such as ionic liquid electrolytes.

  18. Polymerization in emulsion microdroplet reactors

    NASA Astrophysics Data System (ADS)

    Carroll, Nick J.

    The goal of this research project is to utilize emulsion droplets as chemical reactors for execution of complex polymerization chemistries to develop unique and functional particle materials. Emulsions are dispersions of immiscible fluids where one fluid usually exists in the form of drops. Not surprisingly, if a liquid-to-solid chemical reaction proceeds to completion within these drops, the resultant solid particles will possess the shape and relative size distribution of the drops. The two immiscible liquid phases required for emulsion polymerization provide unique and complex chemical and physical environments suitable for the engineering of novel materials. The development of novel non-ionic fluorosurfactants allows fluorocarbon oils to be used as the continuous phase in a water-free emulsion. Such emulsions enable the encapsulation of almost any hydrocarbon compound in droplets that may be used as separate compartments for water-sensitive syntheses. Here, we exemplify the promise of this approach by suspension polymerization of polyurethanes (PU), in which the liquid precursor is emulsified into droplets that are then converted 1:1 into polymer particles. The stability of the droplets against coalescence upon removal of the continuous phase by evaporation confirms the formation of solid PU particles. These results prove that the water-free environment of fluorocarbon based emulsions enables high conversion. We produce monodisperse, cross-linked, and fluorescently labeled PU-latexes with controllable mesh size through microfluidic emulsification in a simple one-step process. A novel method for the fabrication of monodisperse mesoporous silica particles is presented. It is based on the formation of well-defined equally sized emulsion droplets using a microfluidic approach. The droplets contain the silica precursor/surfactant solution and are suspended in hexadecane as the continuous oil phase. The solvent is then expelled from the droplets, leading to

  19. Polymerization of tobacco mosaic virus protein without and with hydrogen ion binding.

    PubMed

    Shalaby, R A; Lauffer, M A

    1983-05-01

    When tobacco mosaic virus (TMV) protein is polymerized at pH values above 7 in unbuffered solutions, either by raising temperature at constant ionic strength or by increasing ionic strength at constant temperature, a 20 S component is formed having bound only the very small amount of H+ ion supplied by the unpolymerized protein. When hydrogen ion is added by titration during polymerization so as to keep pH constant, as would occur automatically if a buffer were present, a 20 S component is formed with one H+ ion bound each for half of the subunits. Thus, a 20 S form with and a 20 S form without bound H+ ion exist. Furthermore, the 20 S form without bound H+ ion binds H+ ion when supplied by titration to produce a 20 S form with the same amount of bound H+ ion as when H+ ion is supplied during the polymerization.

  20. Glutathione-based zwitterionic stationary phase for hydrophilic interaction/cation-exchange mixed-mode chromatography.

    PubMed

    Shen, Aijin; Li, Xiuling; Dong, Xuefang; Wei, Jie; Guo, Zhimou; Liang, Xinmiao

    2013-11-01

    As a naturally hydrophilic peptide, glutathione was facilely immobilized onto silica surface to obtain a novel hydrophilic interaction/cation-exchange mixed-mode chromatographic stationary phase (Click TE-GSH) via copper-free "thiol-ene" click chemistry. The resulting material was characterized by solid state (13)C/CP MAS NMR and elemental analysis. The measurement of ζ-potential indicated the cation-exchange characteristics and adjustable surface charge density of Click TE-GSH material. The influence of acetonitrile content and pH value on the retention of ionic compounds was investigated for understanding the chromatographic behaviors. The results demonstrated that Click TE-GSH column could provide both hydrophilic and cation-exchange interaction. Taking advantage of the good hydrophilicity and inherent cation-exchange characteristics of Click TE-GSH material, the resolution of neutral fructosan with high degree of polymerization (DP), basic chitooligosaccharides and strongly acidic carrageenan oligosaccharides was successfully realized in hydrophilic interaction chromatography (HILIC), hydrophilic interaction/cation-exchange mixed-mode chromatography (HILIC/CEX), cation-exchange chromatography (CEX) and electrostatic repulsion/hydrophilic interaction chromatography (ERLIC). On the other hand, the separation of standard peptides varying in hydrophobicity/hydrophilicity and charge was achieved in both CEX and HILIC/CEX mode with high efficiency and distinct selectivity. To further demonstrate the versatility and applicability of Click TE-GSH stationary phase, the separation of a human serum albumin (HSA) tryptic digest was performed in HILIC/CEX mode. Peptides were adequately resolved and up to 86 HSA peptides were identified with sequence coverage of 85%. The results indicated the good potential of Click TE-GSH material in glycomics and proteomics. PMID:24075460

  1. Tuning Ion Conducting Pathways Using Holographic Polymerization

    NASA Astrophysics Data System (ADS)

    Smith, Derrick; Li, Christopher; Dong, Bin; Bunning, Timothy

    2012-02-01

    While much research has demonstrated repeatable characteristics of electrolyte membranes, the fundamentals behind the interactions during ionic diffusion in solid polymer electrolyte membranes for battery applications are not well understood, specifically the role of nanostructures, which hold the key to improving performance of energy storage devices such as fuel cells and Lithium ion batteries. The challenges in fabricating highly controlled model systems are largely responsible for the interdependent ambiguities between nanostructures and the corresponding ion conducting behavior. In this work, Holographic Polymer Electrolyte Membranes (hPEM) volume gratings comprised of alternating layers of crosslinked polymer resin and lithium ion salt were fabricated using holographic polymerization with an average d-spacing of approximately 200 nm. These one-dimensional confinement structures were used to quantitatively study the anisotropic ionic conductivity between the directions of in-plane and normal to the layers, and the unique ion conducting behavior was correlated with nanoscale phase separation. These volume gratings also offer an exciting route to fabricate multifunctional gratings for optic and sensing applications.

  2. Development of Practical Supported Ionic Liquid Membranes: A Systematic Approach

    SciTech Connect

    Luebke, D.R.; Ilconich, J.B.; Myers, C.R.; Pennline, H.W.

    2007-11-01

    Supported liquid membranes (SLMs) are a class of materials that allow the researcher to utilize the wealth of knowledge available on liquid properties to optimize membrane performance. These membranes also have the advantage of liquid phase diffusivities, which are higher than those observed in polymers and grant proportionally greater permeabilities. The primary shortcoming of the supported liquid membranes demonstrated in past research has been the lack of stability caused by volatilization of the transport liquid. Ionic liquids, which may possess high CO2 solubility relative to light gases such as H2, are excellent candidates for this type of membrane since they are stable at elevated temperatures and have negligible vapor pressure. A study has been conducted evaluating the use of a variety of ionic liquids in supported ionic liquid membranes for the capture of CO2 from streams containing H2. In a joint project, researchers at the University of Notre Dame synthesized and characterized ionic liquids, and researchers at the National Energy Technology Laboratory incorporated candidate ionic liquids into supports and evaluated membrane performance for the resulting materials. Several steps have been taken in the development of practical supported ionic liquid membranes. Proof-of-concept was established by showing that ionic liquids could be used as the transport media in SLMs. Results showed that ionic liquids are suitable media for gas transport, but the preferred polymeric supports were not stable at temperatures above 135oC. The use of cross-linked nylon66 supports was found to produce membranes mechanically stable at temperatures exceeding 300oC but CO2/H2 selectivity was poor. An ionic liquid whose selectivity does not decrease with increasing temperature was needed, and a functionalized ionic liquid that complexes with CO2 was used. An increase in CO2/H2 selectivity with increasing temperature over the range of 37 to 85oC was observed and the dominance of a

  3. On the concept of ionicity in ionic liquids.

    PubMed

    MacFarlane, Douglas R; Forsyth, Maria; Izgorodina, Ekaterina I; Abbott, Andrew P; Annat, Gary; Fraser, Kevin

    2009-07-01

    Ionic liquids are liquids comprised totally of ions. However, not all of the ions present appear to be available to participate in conduction processes, to a degree that is dependent on the nature of the ionic liquid and its structure. There is much interest in quantifying and understanding this 'degree of ionicity' phenomenon. In this paper we present transport data for a range of ionic liquids and evaluate the data firstly in terms of the Walden plot as an approximate and readily accessible approach to estimating ionicity. An adjusted Walden plot that makes explicit allowance for differences in ion sizes is shown to be an improvement to this approach for the series of ionic liquids described. In some cases, where diffusion measurements are possible, it is feasible to directly quantify ionicity via the Nernst-Einstein equation, confirming the validity of the adjusted Walden plot approach. Some of the ionic liquids studied exhibit ionicity values very close to ideal; this is discussed in terms of a model of a highly associated liquid in which the ion correlations have similar impact on both the diffusive and conductive motions. Ionicity, as defined, is thus a useful measure of adherence to the Nernst-Einstein equation, but is not necessarily a measure of ion availability in the chemical sense. PMID:19562126

  4. Ionic contrast terahertz near field imaging

    NASA Astrophysics Data System (ADS)

    Gallot, Guilhem

    2013-09-01

    We demonstrated the direct and noninvasive imaging of functional neurons by Ionic Contrast Terahertz (ICT) near-field microscopy. This technique provides quantitative measurements of ionic concentrations in both the intracellular and extracellular compartments and opens the way to direct noninvasive imaging of neurons during electrical, toxin, or thermal stresses. Furthermore, neuronal activity results from both a precise control of transient variations in ionic conductance and a much less studied water exchange between the extracellular matrix and the intraaxonal compartment. The developed ICT technique associated with a full three-dimensional simulation of the axon-aperture near-field system allows a precise measurement of the axon geometry and therefore the direct visualization of neuron swelling induced by temperature change or neurotoxin poisoning. We also developed Terahertz Attenuated Total Reflection (ATR) devices perfectly suited for studying cell layers. Inserted in a terahertz time-domain system, and using a high resistivity low loss silicon prism to couple the terahertz wave into the sample, the detection scheme is based on the relative differential spectral phase of two orthogonal polarizations. Biological sample imaging as well as subwavelength (λ/16) longitudinal resolution are demonstrated.

  5. ESR spin probes in ionic liquids.

    PubMed

    Stoesser, Reinhard; Herrmann, Werner; Zehl, Andrea; Strehmel, Veronika; Laschewsky, André

    2006-05-12

    The spin probes 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL), and 2,2,6,6-tetramethyl-4-trimethylammoniumpiperidine-1-oxylIodide (CAT-1) are examined in a number of ionic liquids based on substituted imidazolium cations and tetrafluoroborate and hexafluorophosphate anions, respectively. The reorientation correlation times tau(R) of the spin probes in these systems have been determined by complete spectra simulation and, for rapid reortientation, by analysis of the intensities of the hyperfine lines of the electron spin resonance (ESR) spectra. A comparison of the results with those from the model system glycerol/water and selected organic solvents is made. Additions of diamagnetic and paramagnetic ions allow the conclusion that salt effects and spin exchange are present, and that both are superimposed by motional effects. Specific interactions in the ionic liquids, as well as between the spin-probe molecules and the constituents of the ionic liquids are reflected in the spectra of the spin probes, depending on their molecular structure.

  6. Thallium Transfer from Hydrochloric Acid Media into Pure Ionic Liquids.

    PubMed

    Tereshatov, Evgeny E; Boltoeva, Maria Yu; Mazan, Valerie; Volia, Merinda F; Folden, Charles M

    2016-03-10

    Pure hydrophobic ionic liquids are known to extract metallic species from aqueous solutions. In this work we have systematically investigated thallium (Tl) extraction from aqueous hydrochloric acid (HCl) solutions into six pure fluorinated ionic liquids, namely imidazolium- and pyrrolidinium-based ionic liquids with bis(trifluoromethanesulfonyl)imide and bis(fluorosulfonyl)-imide anions. The dependence of the Tl extraction efficiency on the structure and composition of the ionic liquid ions, metal oxidation state, and initial metal and aqueous acid concentrations have been studied. Tl concentrations were on the order of picomolar (analyzed using radioactive tracers) and millimolar (analyzed using inductively coupled plasma mass spectrometry). The extraction of the cationic thallium species Tl(+) is higher for ionic liquids with more hydrophilic cations, while for the TlX(z)(3-z) anionic species (where X = Cl(-) and/or Br(-)), the extraction efficiency is greater for ionic liquids with more hydrophobic cations. The highest distribution value of Tl(III) was approximately 2000. An improved mathematical model based on ion exchange and ion pair formation mechanisms has been developed to describe the coextraction of two different anionic species, and the relative contributions of each mechanism have been determined. PMID:26769597

  7. Nanostructural magnetism of polymeric fullerene crystals

    SciTech Connect

    Sheka, E. F. Zaets, V. A.; Ginzburg, I. Ya.

    2006-11-15

    The nature of magnetism in all-carbon crystals composed of polymeric layers of covalently bound fullerene (C{sub 60}) molecules is considered. The results of quantum-chemical calculations performed using the unrestricted Hartree-Fock approximation and the semiempirical AM1 method are presented. It is shown that the exchange integrals J of both a free C{sub 60} molecule and a monomer unit of the polymer are too large ensure the required magnetic susceptibility of the fullerene crystal. However, the J value exhibits an approximately n-fold decrease for an oligomer molecule consisting of n C{sub 60} units. Therefore, in the case of large n, the exchange integral can be reduced to a low level sufficient to provide for a significant magnetic susceptibility. A nanosize (scaly) model of the observed magnetism is proposed that is consistent with recent experimental data, which are indicative of a nanostructural character of magnetic fullerene samples.

  8. Surface polymerization agents

    SciTech Connect

    Taylor, C.; Wilkerson, C.

    1996-12-01

    This is the final report of a 1-year, Laboratory-Directed R&D project at LANL. A joint technical demonstration was proposed between US Army Missile Command (Redstone Arsenal) and LANL. Objective was to demonstrate that an unmanned vehicle or missile could be used as a platform to deliver a surface polymerization agent in such a manner as to obstruct the filters of an air-breathing mechanism, resulting in operational failure.

  9. Polymeric Bicontinuous Microemulsions

    NASA Astrophysics Data System (ADS)

    Bates, Frank S.; Maurer, Wayne W.; Lipic, Paul M.; Hillmyer, Marc A.; Almdal, Kristoffer; Mortensen, Kell; Fredrickson, Glenn H.; Lodge, Timothy P.

    1997-08-01

    High molecular weight block copolymers can be viewed as macromolecular surfactants when blended with thermodynamically incompatible homopolymers. This Letter describes the formation of polymeric bicontinuous microemulsions in mixtures containing a model diblock copolymer and two homopolymers. Although we attribute development of this equilibrium morphology to the effects of fluctuations, mean-field theory provides a quantitative strategy for preparing the bicontinuous state at blend compositions near an isotropic Lifshitz point.

  10. Super ionic conductive glass

    DOEpatents

    Susman, Sherman; Volin, Kenneth J.

    1984-01-01

    An ionically conducting glass for use as a solid electrolyte in a power or secondary cell containing an alkali metal-containing anode and a cathode separated by an alkali metal ion conducting glass having an ionic transference number of unity and the general formula: A.sub.1+x D.sub.2-x/3 Si.sub.x P.sub.3-x O.sub.12-2x/3, wherein A is a network modifier for the glass and is an alkali metal of the anode, D is an intermediate for the glass and is selected from the class consisting of Zr, Ti, Ge, Al, Sb, Be, and Zn and X is in the range of from 2.25 to 3.0. Of the alkali metals, Na and Li are preferred and of the intermediate, Zr, Ti and Ge are preferred.

  11. Super ionic conductive glass

    DOEpatents

    Susman, S.; Volin, K.J.

    Described is an ionically conducting glass for use as a solid electrolyte in a power or secondary cell containing an alkali metal-containing anode and a cathode separated by an alkali metal ion conducting glass having an ionic transference number of unity and the general formula: A/sub 1 + x/D/sub 2-x/3/Si/sub x/P/sub 3 - x/O/sub 12 - 2x/3/, wherein A is a network modifier for the glass and is an alkali metal of the anode, D is an intermediate for the glass and is selected from the class consisting of Zr, Ti, Ge, Al, Sb, Be, and Zn and X is in the range of from 2.25 to 3.0. Of the alkali metals, Na and Li are preferred and of the intermediate, Zr, Ti and Ge are preferred.

  12. Encapsulation of Ln(III) Ions/Dyes within a Microporous Anionic MOF by Post-synthetic Ionic Exchange Serving as a Ln(III) Ion Probe and Two-Color Luminescent Sensors.

    PubMed

    Zhao, Shu-Na; Song, Xue-Zhi; Zhu, Min; Meng, Xing; Wu, Lan-Lan; Feng, Jing; Song, Shu-Yan; Zhang, Hong-Jie

    2015-06-26

    A new anionic framework {[Me2NH2]0.125[In0.125(H2L)0.25]⋅xDMF}n (1) with one-dimensional (1D) channels along the c axis of about 13.06×13.06 Å(2), was solvothermally synthesized and well characterized. Post-synthetic cation exchange of 1 with Eu(3+), Tb(3+), Dy(3+), Sm(3+) afforded lanthanide(III)-loaded materials, Ln(3+)@1, with different luminescent behavior, indicating that compound 1 could be used as a potential luminescent probe toward different lanthanide(III) ions. Additionally, compound 1 exhibits selective adsorption ability toward cationic dyes. Moreover, the RhB@1 realized the probing of different organic solvent molecules by tuning the energy transfer efficiency between two different emissions, especially for sensing DMF. This work highlights the practical application of luminescent guest@MOFs as sensors, and it paves the way toward other one/multi-color luminescent host-guest systems by rational selection of MOF hosts and guest chromophores with suitable emissive colors and energy levels.

  13. Toward complementary ionic circuits: the npn ion bipolar junction transistor.

    PubMed

    Tybrandt, Klas; Gabrielsson, Erik O; Berggren, Magnus

    2011-07-01

    Many biomolecules are charged and may therefore be transported with ionic currents. As a step toward addressable ionic delivery circuits, we report on the development of a npn ion bipolar junction transistor (npn-IBJT) as an active control element of anionic currents in general, and specifically, demonstrate actively modulated delivery of the neurotransmitter glutamic acid. The functional materials of this transistor are ion exchange layers and conjugated polymers. The npn-IBJT shows stable transistor characteristics over extensive time of operation and ion current switch times below 10 s. Our results promise complementary chemical circuits similar to the electronic equivalence, which has proven invaluable in conventional electronic applications. PMID:21598973

  14. Incorporation of ionic liquid into porous polymer monoliths to enhance the separation of small molecules in reversed-phase high-performance liquid chromatography.

    PubMed

    Wang, Jiafei; Bai, Ligai; Wei, Zhen; Qin, Junxiao; Ma, Yamin; Liu, Haiyan

    2015-06-01

    An ionic liquid was incorporated into the porous polymer monoliths to afford stationary phases with enhanced chromatographic performance for small molecules in reversed-phase high-performance liquid chromatography. The effect of the ionic liquid in the polymerization mixture on the performance of the monoliths was studied in detail. While monoliths without ionic liquid exhibited poor resolution and low efficiency, the addition of ionic liquid to the polymerization mixture provides highly increased resolution and high efficiency. The chromatographic performances of the monoliths were demonstrated by the separations of various small molecules including aromatic hydrocarbons, isomers, and homologues using a binary polar mobile phase. The present column efficiency reached 27 000 plates/m, which showed that the ionic liquid monoliths are alternative stationary phases in the separation of small molecules by high-performance liquid chromatography.

  15. Thermodynamic estimation: Ionic materials

    SciTech Connect

    Glasser, Leslie

    2013-10-15

    Thermodynamics establishes equilibrium relations among thermodynamic parameters (“properties”) and delineates the effects of variation of the thermodynamic functions (typically temperature and pressure) on those parameters. However, classical thermodynamics does not provide values for the necessary thermodynamic properties, which must be established by extra-thermodynamic means such as experiment, theoretical calculation, or empirical estimation. While many values may be found in the numerous collected tables in the literature, these are necessarily incomplete because either the experimental measurements have not been made or the materials may be hypothetical. The current paper presents a number of simple and relible estimation methods for thermodynamic properties, principally for ionic materials. The results may also be used as a check for obvious errors in published values. The estimation methods described are typically based on addition of properties of individual ions, or sums of properties of neutral ion groups (such as “double” salts, in the Simple Salt Approximation), or based upon correlations such as with formula unit volumes (Volume-Based Thermodynamics). - Graphical abstract: Thermodynamic properties of ionic materials may be readily estimated by summation of the properties of individual ions, by summation of the properties of ‘double salts’, and by correlation with formula volume. Such estimates may fill gaps in the literature, and may also be used as checks of published values. This simplicity arises from exploitation of the fact that repulsive energy terms are of short range and very similar across materials, while coulombic interactions provide a very large component of the attractive energy in ionic systems. Display Omitted - Highlights: • Estimation methods for thermodynamic properties of ionic materials are introduced. • Methods are based on summation of single ions, multiple salts, and correlations. • Heat capacity, entropy

  16. 3-Methylpiperidinium ionic liquids.

    PubMed

    Belhocine, Tayeb; Forsyth, Stewart A; Gunaratne, H Q Nimal; Nieuwenhuyzen, Mark; Nockemann, Peter; Puga, Alberto V; Seddon, Kenneth R; Srinivasan, Geetha; Whiston, Keith

    2015-04-28

    A wide range of room temperature ionic liquids based on the 3-methylpiperdinium cation core were produced from 3-methylpiperidine, which is a derivative of DYTEK® A amine. First, reaction with 1-bromoalkanes or 1-bromoalkoxyalkanes generated the corresponding tertiary amines (Rmβpip, R = alkyl or alkoxyalkyl); further quaternisation reactions with the appropriate methylating agents yielded the quaternary [Rmmβpip]X salts (X(-) = I(-), [CF3CO2](-) or [OTf](-); Tf = -SO2CF3), and [Rmmβpip][NTf2] were prepared by anion metathesis from the corresponding iodides. All [NTf2](-) salts are liquids at room temperature. [Rmmβpip]X (X(-) = I(-), [CF3CO2](-) or [OTf](-)) are low-melting solids when R = alkyl, but room temperature liquids upon introduction of ether functionalities on R. Neither of the 3-methylpiperdinium ionic liquids showed any signs of crystallisation, even well below 0 °C. Some related non-C-substituted piperidinium and pyrrolidinium analogues were prepared and studied for comparison. Crystal structures of 1-hexyl-1,3-dimethylpiperidinium tetraphenylborate, 1-butyl-3-methylpiperidinium bromide, 1-(2-methoxyethyl)-1-methylpiperidinium chloride and 1-(2-methoxyethyl)-1-methylpyrrolidinium bromide are reported. Extensive structural and physical data are collected and compared to literature data, with special emphasis on the systematic study of the cation ring size and/or asymmetry effects on density, viscosity and ionic conductivity, allowing general trends to be outlined. Cyclic voltammetry shows that 3-methylpiperidinium ionic liquids, similarly to azepanium, piperidinium or pyrrolidinium counterparts, are extremely electrochemically stable; the portfolio of useful alternatives for safe and high-performing electrolytes is thus greatly extended. PMID:25669485

  17. Cyclic phosphonium ionic liquids

    PubMed Central

    Mukhlall, Joshua A; Romeo, Alicia R; Gohdo, Masao; Ramati, Sharon; Berman, Marc; Suarez, Sophia N

    2014-01-01

    Summary Ionic liquids (ILs) incorporating cyclic phosphonium cations are a novel category of materials. We report here on the synthesis and characterization of four new cyclic phosphonium bis(trifluoromethylsulfonyl)amide ILs with aliphatic and aromatic pendant groups. In addition to the syntheses of these novel materials, we report on a comparison of their properties with their ammonium congeners. These exemplars are slightly less conductive and have slightly smaller self-diffusion coefficients than their cyclic ammonium congeners. PMID:24605146

  18. Lanthanum-NaY zeolite ion exchange. 2; Kinetics

    SciTech Connect

    Lee, T.Y.; Lu, T.S.; Chen, S.H.; Chao, K.J. )

    1990-10-01

    This paper reports on La-NaY ion exchange breakthrough curves which were obtained experimentally at 27 and 60{degrees}C. A mathematical model of an ion exchanger was formulated and employed to calculate the ion exchanger coefficients. An ionic diffusion coefficient of the order of 10{sup {minus}8} cm{sup 2}/s was obtained. The effects of zeolite particle size, temperature, and column packing conditions on the kinetics of the exchange were investigated also.

  19. The influence of various cations on the catalytic properties of clays. [polymerization of alanine adenylate

    NASA Technical Reports Server (NTRS)

    Paecht-Horowitz, M.

    1978-01-01

    The polymerization of alanine adenylate in the presence of the sodium form of various clays was studied, and hectorite was found to cause more polymerization than nontronite and montmorillonite (in that order) although the differences were not great. The effect on polymerization of presaturating montmorillonite with different cations was determined. Hectorite, with increased basicity of the interspatial planes, allows polymerization of lysine, which montmorillonite does not. The general trend is that, for the same amino acid, higher degrees of polymerization are obtained when the cation in the octahedral lattice of the clay is divalent rather than trivalent. With the exchangeable cations the order is reversed, for a reason that is explained. The main role of clays in the polymerization mechanism of amino acids is concentration and neutralization of charges.

  20. Carbon Dioxide Separation with Supported Ionic Liquid Membranes

    SciTech Connect

    Luebke, D.R.; Ilconich, J.B.; Myers, C.R.; Pennline, H.W.

    2007-04-01

    Supported liquid membranes are a class of materials that allow the researcher to utilize the wealth of knowledge available on liquid properties as a direct guide in the development of a capture technology. These membranes also have the advantage of liquid phase diffusivities higher than those observed in polymeric membranes which grant proportionally greater permeabilities. The primary shortcoming of the supported liquid membranes demonstrated in past research has been the lack of stability caused by volatilization of the transport liquid. Ionic liquids, which possess high carbon dioxide solubility relative to light gases such as hydrogen, are an excellent candidate for this type of membrane since they have negligible vapor pressure and are not susceptible to evaporation. A study has been conducted evaluating the use of several ionic liquids, including 1-hexyl-3-methyl-imidazolium bis(trifuoromethylsulfonyl)imide, 1-butyl-3-methyl-imidazolium nitrate, and 1-ethyl-3-methyl-imidazolium sulfate in supported ionic liquid membranes for the capture of carbon dioxide from streams containing hydrogen. In a joint project, researchers at the University of Notre Dame lent expertise in ionic liquid synthesis and characterization, and researchers at the National Energy Technology Laboratory incorporated candidate ionic liquids into supports and evaluated the resulting materials for membrane performance. Initial results have been very promising with carbon dioxide permeabilities as high as 950 barrers and significant improvements in carbon dioxide/hydrogen selectivity over conventional polymers at 37C and at elevated temperatures. Results include a comparison of the performance of several ionic liquids and a number of supports as well as a discussion of innovative fabrication techniques currently under development.

  1. Shape memory rubber bands & supramolecular ionic copolymers

    NASA Astrophysics Data System (ADS)

    Brostowitz, Nicole

    subject covered in this dissertation is supra-molecular ionic copolymers. Supramolecular interactions are non-covalent; e.g. hydrogen bonding, ionic interactions, van der Waals forces. Supramolecular interactions in polymers can be used to tailor the thermo-mechanical properties by controlling bond association and dissociation. Recent research has focused on hydrogen bonded systems due to established synthesis mechanisms. Reversibility of the supramolecular interactions can be triggered by environmental changes. Ionic interactions would provide greater bond strength and more control over operating conditions. Research has been limited on ionic copolymers due to complicated synthesis methods needed to include functionalization. Low molecular weight polymers were synthesized by atom transfer radical polymerization with post polymerization conversion to phosphonium end-groups. Both polystyrene and poly(methyl acrylate) were investigated with similar reaction conditions. Chromatography measured the molecular weight and indicated a low polydispersity consistent with controlled reactions. Copolymers were formed by interfacial mixing of the cationic polymers with multifunctional, anionic oligomers. Oligomers containing sulfonate groups were used to create linear or three-dimensional polymer networks. NMR and rheology was used to characterize the presence and effect of ionic groups when compared to the neat polymer.

  2. Stable and water-tolerant ionic liquid ferrofluids.

    PubMed

    Jain, Nirmesh; Zhang, Xiaoli; Hawkett, Brian S; Warr, Gregory G

    2011-03-01

    Ionic liquid ferrofluids have been prepared containing both bare and sterically stabilized 8-12 nm diameter superparamagnetic iron oxide nanoparticles, which remain stable for several months in both protic ethylammonium and aprotic imidazolium room-temperature ionic liquids. These ferrofluids exhibit spiking in static magnetic fields similar to conventional aqueous and nonaqueous ferrofluids. Ferrofluid stability was verified by following the flocculation and settling behavior of dilute nanoparticle dispersions. Although bare nanoparticles showed excellent stability in some ILs, they were unstable in others, and exhibited limited water tolerance. Stability was achieved by incorporating a thin polymeric steric stabilization layer designed to be compatible with the IL. This confers the added benefit of imbuing the ILF with a high tolerance to water. PMID:21338083

  3. Characterization of the interactions between polymethacrylate-based aqueous polymeric dispersions and aluminum lakes.

    PubMed

    Nyamweya, N; Mehta, K A; Hoag, S W

    2001-12-01

    Instability in film coating formulations can arise from interactions between aluminum lake pigments and aqueous polymeric dispersions. The purpose of this study was to characterize the interactions between three polymethacrylate-based aqueous polymeric dispersions (Eudragit RS 30 D, Eudragit L 30 D-55, and Eudragit NE 30 D) and aluminum lakes. Particle size measurements, pH stability profiles, zeta potential measurements, and microscopy were used to study mixed dispersions of the polymeric latices and the lakes. Interactions leading to dispersion instability were related to the surface charge of the components in the formulation. Interactions between the ionic polymers and the lakes arose from instability of the lakes outside a certain pH range resulting in the release of electrolytes, which led to aggregation of the polymeric particles. Interactions between the nonionic polymer and the lakes were related to the polymer modifying the surface charge of the lakes, resulting in aggregation of the pigment particles.

  4. Preparation of metallic cation conducting polymers based on sterically hindered phenols containing polymeric systems

    DOEpatents

    Skotheim, Terje A.; Okamoto, Yoshiyuki; Lee, Hung S.

    1989-01-01

    The present invention relates to ion-conducting solvent-free polymeric systems characterized as being cationic single ion conductors. The solvent-free polymer electrolytes comprise a flexible polymer backbone to which is attached a metal salt, such as a lithium, sodium or potassium salt, of a sterically hindered phenol. The solid polymer electrolyte may be prepared either by (1) attaching the hindered phenol directly to a flexible polymeric backbone, followed by neutralization of the phenolic OH's or (2) reacting the hindered phenol with a polymer precursor which is then polymerized to form a flexible polymer having phenolic OH's which are subsequently neutralized. Preferably the hindered phenol-modified polymeric backbone contains a polyether segment. The ionic conductivity of these solvent-free polymer electrolytes has been measured to be in the range of 10.sup.-4 to 10.sup.-7 S cm.sup.-1 at room temperature.

  5. Preparation of metallic cation conducting polymers based on sterically hindered phenols containing polymeric systems

    DOEpatents

    Skotheim, T.A.; Okamoto, Yoshiyuki; Lee, H.S.

    1989-11-21

    The present invention relates to ion-conducting solvent-free polymeric systems characterized as being cationic single ion conductors. The solvent-free polymer electrolytes comprise a flexible polymer backbone to which is attached a metal salt, such as a lithium, sodium or potassium salt, of a sterically hindered phenol. The solid polymer electrolyte may be prepared either by (1) attaching the hindered phenol directly to a flexible polymeric backbone, followed by neutralization of the phenolic OH's or (2) reacting the hindered phenol with a polymer precursor which is then polymerized to form a flexible polymer having phenolic OH's which are subsequently neutralized. Preferably the hindered phenol-modified polymeric backbone contains a polyether segment. The ionic conductivity of these solvent-free polymer electrolytes has been measured to be in the range of 10[sup [minus]4] to 10[sup [minus]7] S cm[sup [minus]1] at room temperature.

  6. PEDOT Electrochemical Polymerization Improves Electrode Fidelity and Sensitivity

    PubMed Central

    Frost, Christopher M.; Wei, Benjamin; Baghmanli, Ziya; Cederna, Paul S.; Urbanchek, Melanie G.

    2015-01-01

    Background The goal of the authors is to restore fine motor control and sensation for high-arm amputees. They developed a regenerative peripheral nerve interface with the aim of attaining closed loop neural control by integrating directly with the amputee's residual motor and sensory peripheral nerves. PEDOT, poly(3,4-ethylenedioxythiophene), has both electrical and ionic conduction characteristics. This hybrid character could help bridge the salutatory conduction of the nervous system to an electrode. The purpose of this study was to determine whether electrodes polymerized with PEDOT have improved ability to both record and stimulate peripheral nerve action potentials. Methods Impedance spectroscopy and cyclic voltammetry were performed on electrodes before and after polymerization to measure electrode impedance and charge capacity. Both recording needle and bipolar stimulating electrodes were polymerized with PEDOT. Plain and PEDOT electrodes were tested using rat (n = 18) in situ nerve conduction studies. The peroneal nerve was stimulated using a bipolar electrode at multiple locations along the nerve. Action potentials were measured in the extensor digitorum longus muscle. Results Bench testing showed PEDOT electrodes had a higher charge capacity and lower impedance than plain electrodes, indicating significantly improved electrode fidelity. Nerve conduction testing indicated a significant reduction in the stimulus threshold for both PEDOT recording and PEDOT stimulatory electrodes when compared with plain electrodes, indicating an increase in sensitivity. Conclusions PEDOT electrochemical polymerization improves electrode fidelity. Electrodes that have been electropolymerized with PEDOT show improved sensitivity when recording or stimulating action potentials at the tissue–electrode interface. PMID:22456363

  7. Bimorphic polymeric photomechanical actuator

    NASA Technical Reports Server (NTRS)

    Sarkisov, Sergey S. (Inventor); Curley, Michael J. (Inventor); Adamovsky, Grigory (Inventor); Sarkisov, Jr., Sergey S. (Inventor); Fields, Aisha B. (Inventor)

    2006-01-01

    A bimorphic polymeric photomechanical actuator, in one embodiment using polyvinylidene fluoride (PVDF) as a photosensitive body, transmitting light over fiber optic cables, and controlling the shape and pulse duration of the light pulse to control movement of the actuator. Multiple light beams are utilized to generate different ranges of motion for the actuator from a single photomechanical body and alternative designs use multiple light beams and multiple photomechanical bodies to provide controlled movement. Actuator movement using one or more ranges of motion is utilized to control motion to position an actuating element in three dimensional space.

  8. Living olefin polymerization processes

    DOEpatents

    Schrock, Richard R.; Baumann, Robert

    2003-08-26

    Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.

  9. Living olefin polymerization processes

    DOEpatents

    Schrock, Richard R.; Baumann, Robert

    1999-01-01

    Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.

  10. Living olefin polymerization processes

    DOEpatents

    Schrock, R.R.; Baumann, R.

    1999-03-30

    Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.

  11. Living olefin polymerization processes

    DOEpatents

    Schrock, Richard R.; Bauman, Robert

    2006-11-14

    Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.

  12. Polymerization Evaluation by Spectrophotometric Measurements.

    ERIC Educational Resources Information Center

    Dunach, Jaume

    1985-01-01

    Discusses polymerization evaluation by spectrophotometric measurements by considering: (1) association degrees and molar absorptivities; (2) association degrees and equilibrium constants; and (3) absorbance and equilibrium constants. (JN)

  13. Ionic liquids, electrolyte solutions including the ionic liquids, and energy storage devices including the ionic liquids

    SciTech Connect

    Gering, Kevin L.; Harrup, Mason K.; Rollins, Harry W.

    2015-12-08

    An ionic liquid including a phosphazene compound that has a plurality of phosphorus-nitrogen units and at least one pendant group bonded to each phosphorus atom of the plurality of phosphorus-nitrogen units. One pendant group of the at least one pendant group comprises a positively charged pendant group. Additional embodiments of ionic liquids are disclosed, as are electrolyte solutions and energy storage devices including the embodiments of the ionic liquid.

  14. Organometallic Polymeric Conductors

    NASA Technical Reports Server (NTRS)

    1997-01-01

    For aerospace applications, the use of polymers can result in tremendous weight savings over metals. Suitable polymeric materials for some applications like EMI shielding, spacecraft grounding, and charge dissipation must combine high electrical conductivity with long-term environmental stability, good processability, and good mechanical properties. Recently, other investigators have reported hybrid films made from an electrically conductive polymer combined with insulating polymers. In all of these instances, the films were prepared by infiltrating an insulating polymer with a precursor for a conductive polymer (either polypyrrole or polythiophene), and oxidatively polymerizing the precursor in situ. The resulting composite films have good electrical conductivity, while overcoming the brittleness inherent in most conductive polymers. The highest conductivities reported (approximately 4/Scm) were achieved with polythiophene in a polystyrene host polymer. The best films using a polyamide as base polymer were four orders of magnitude less conductive than the polystyrene films. The authors suggested that this was because polyimides were unable to swell sufficiently for infiltration of monomer as in the polystyrene. It was not clear, however, if the different conductivities obtained were merely the result of differing oxidation conditions. Oxidation time, temperature and oxidant concentration varied widely among the studies.

  15. Role of Heavy Meromyosin in Heat-Induced Gelation in Low Ionic Strength Solution Containing L-Histidine.

    PubMed

    Hayakawa, Toru; Yoshida, Yuri; Yasui, Masanori; Ito, Toshiaki; Wakamatsu, Jun-ichi; Hattori, Akihito; Nishimura, Takanori

    2015-08-01

    The gelation of myosin has a very important role in meat products. We have already shown that myosin in low ionic strength solution containing L-histidine forms a transparent gel after heating. To clarify the mechanism of this unique gelation, we investigated the changes in the nature of myosin subfragments during heating in solutions with low and high ionic strengths with and without L-histidine. The hydrophobicity of myosin and heavy meromyosin (HMM) in low ionic strength solution containing L-histidine was lower than in high ionic strength solution. The SH contents of myosin and HMM in low ionic strength solution containing l-histidine did not change during the heating process, whereas in high ionic strength solution they decreased slightly. The heat-induced globular masses of HMM in low ionic strength solution containing L-histidine were smaller than those in high ionic strength solution. These findings suggested that the polymerization of HMM molecules by heating was suppressed in low ionic strength solution containing L-histidine, resulting in formation of the unique gel.

  16. Role of Heavy Meromyosin in Heat-Induced Gelation in Low Ionic Strength Solution Containing L-Histidine.

    PubMed

    Hayakawa, Toru; Yoshida, Yuri; Yasui, Masanori; Ito, Toshiaki; Wakamatsu, Jun-ichi; Hattori, Akihito; Nishimura, Takanori

    2015-08-01

    The gelation of myosin has a very important role in meat products. We have already shown that myosin in low ionic strength solution containing L-histidine forms a transparent gel after heating. To clarify the mechanism of this unique gelation, we investigated the changes in the nature of myosin subfragments during heating in solutions with low and high ionic strengths with and without L-histidine. The hydrophobicity of myosin and heavy meromyosin (HMM) in low ionic strength solution containing L-histidine was lower than in high ionic strength solution. The SH contents of myosin and HMM in low ionic strength solution containing l-histidine did not change during the heating process, whereas in high ionic strength solution they decreased slightly. The heat-induced globular masses of HMM in low ionic strength solution containing L-histidine were smaller than those in high ionic strength solution. These findings suggested that the polymerization of HMM molecules by heating was suppressed in low ionic strength solution containing L-histidine, resulting in formation of the unique gel. PMID:26148000

  17. Self-stabilized magnetic polymeric composite nanoparticles by emulsifier-free miniemulsion polymerization.

    PubMed

    Lu, Shulai; Ramos, Jose; Forcada, Jacqueline

    2007-12-18

    Self-stabilized magnetic polymeric composite nanoparticles (SS-MPCPs) were prepared by emulsifier-free miniemulsion polymerization using styrene (St) as a monomer, sodium p-styrenesulfonate (NaSS) as an ionic comonomer, hexadecane (HD) as a hydrophobe, and 2,2'-azodiisobutyronitrile (AIBN) as an initiator in the presence of hydrophobic magnetite particles. The hydrophobic magnetite particles with an average size of about 10 nm were prepared by the acidification of the water-based magnetite ferrofluid, previously synthesized by a chemical coprecipitation method. Some colloidal features of the synthesized SS-MPCPs were analyzed. The morphology and the particle size distributions (PSDs) of the SS-MPCPs were observed and analyzed by transmission electron microscopy (TEM). The surface charge density was determined by conductometric titration. The surface hairy layer and the colloidal stability of SS-MPCPs against different electrolytes were determined by photon correlation spectroscopy (PCS). The average Fe3O4 content of SS-MPCPs was determined by thermogravimetric analysis (TGA). Vibrating sample magnetometry (VSM) was used to analyze the magnetic properties of the SS-MPCPs under dry conditions. The results show that the encapsulation of magnetite is successful and the distribution of magnetite particles inside SS-MPCPs is mainly in the core of the particles. The best SS-MPCPs prepared had a relatively narrow PSD, exhibited superparamagnetism, and possessed some magnetic response. PMID:18031070

  18. Enhancement of molecular shape selectivity by in situ anion-exchange in poly(octadecylimidazolium) silica column.

    PubMed

    Qiu, Hongdeng; Mallik, Abul K; Takafuji, Makoto; Liu, Xia; Jiang, Shengxiang; Ihara, Hirotaka

    2012-04-01

    This paper demonstrates that in situ anion exchange could be successfully applied as a new method for modifying the surface properties of a poly(octadecylimidazolium)-grafted silica stationary phase to tune and enhance selectivity. Specifically, the original stationary phase was prepared by surface-initiated radical chain-transfer polymerization of 1-vinyl-3-octadecylimidazolium bromide as an ionic liquid monomer; the Br(-) counter anion was then exchanged for methyl orange via an in-column process. As evaluated via the separation of constrained isomers of polycyclic aromatic hydrocarbons (PAHs), the in situ exchange enhanced the molecular shape-selectivity performance. Enhanced selectivity was also confirmed using Standard Reference Material (SRM) 869b (column selectivity test mixture) and SRM 1647e (16 priority pollutant PAHs). The reproducibility of new column was tested via the separation of pyrene, triphenylene, benzo[a]anthracene and chrysene with methanol as eluent at 10 °C and the RSD values (n=12) of the retention factors of them are within 0.27-0.77%. PMID:22099220

  19. Amplification of actin polymerization forces

    PubMed Central

    Dmitrieff, Serge; Nédélec, François

    2016-01-01

    The actin cytoskeleton drives many essential processes in vivo, using molecular motors and actin assembly as force generators. We discuss here the propagation of forces caused by actin polymerization, highlighting simple configurations where the force developed by the network can exceed the sum of the polymerization forces from all filaments. PMID:27002174

  20. Coating of plasma polymerized film

    NASA Technical Reports Server (NTRS)

    Morita, S.; Ishibashi, S.

    1980-01-01

    Plasma polymerized thin film coating and the use of other coatings is suggested for passivation film, thin film used for conducting light, and solid body lubrication film of dielectrics of ultra insulators for electrical conduction, electron accessories, etc. The special features of flow discharge development and the polymerized film growth mechanism are discussed.

  1. Gold-promoted styrene polymerization.

    PubMed

    Urbano, Juan; Hormigo, A Jesús; de Frémont, Pierre; Nolan, Steven P; Díaz-Requejo, M Mar; Pérez, Pedro J

    2008-02-14

    Styrene can be polymerized at room temperature in the presence of equimolar mixtures of the gold(III) complexes (NHC)AuBr3 (NHC = N-heterocyclic carbene ligand) and NaBAr'4, in the first example of a gold-induced olefin polymerization reaction.

  2. Ionization dynamics in ionic liquids probed via self-diffusion coefficient measurements

    NASA Astrophysics Data System (ADS)

    Mao, Yougang; Damodaran, Krishnan

    2014-08-01

    Ionic liquids contain ions and ion pairs with fast exchange between them. We propose a novel process to deduce the fraction of ions present in an ionic liquid and the equilibrium constants of ionization processes from measured ion self-diffusion coefficients using Pulsed Field Gradient (PFG) NMR. The enthalpy and entropy changes of ionization and ion self-diffusion processes are obtained for a series of ionic liquids using this method. These data were used to explain the interactions between cations and anions of ionic liquids. The interactions are also interpreted by the delocalization of the ion’s charge densities. The self-diffusion coefficients of cations and anions for measured ionic liquids are discussed.

  3. Carbon Dioxide Separation with Supported Ionic Liquid Membranes

    SciTech Connect

    Luebke, D.R.; Ilconich, J.B.; Pennline, H.W.; Myers, C.R.

    2007-05-01

    A practical form of CO2 capture at water-gas shift conditions in the IGCC process could serve the dual function of producing a pure CO2 stream for sequestration and forcing the equilibrium-limited shift reaction to completion enriching the stream in H2. The shift temperatures, ranging from the low temperature shift condition of 260°C to the gasification condition of 900°C, limit capture options by diminishing associative interactions which favor removal of CO2 from the gas stream. Certain sorption interactions, such as carbonate formation, remain available but generally involve exceptionally high sorbent regeneration energies that contribute heavily to parasitic power losses. Carbon dioxide selective membranes need only establish an equilibrium between the gas phase and sorption states in order to transport CO2, giving them a potential energetic advantage over other technologies. Supported liquid membranes take advantage of high, liquid phase diffusivities and a solution diffusion mechanism similar to that observed in polymeric membranes to achieve superior permeabilities and selectivites. The primary shortcoming of the supported liquid membranes demonstrated in past research has been the lack of stability caused by volatilization of the transport liquid. Ionic liquids, which possess high CO2 solubility relative to light gases such as H2, are excellent candidates for this type of membrane since they have negligible vapor pressure and are not susceptible to evaporation. A study has been conducted evaluating the use of ionic liquids including 1-hexyl-3-methyl-imidazolium bis(trifuoromethylsulfonyl)imide in supported ionic liquid membranes for the capture of CO2 from streams containing H2. In a joint project, researchers at the University of Notre Dame synthesized and characterized ionic liquids, and researchers at the National Energy Technology Laboratory incorporated candidate ionic liquids into supports and evaluated the resulting materials for membrane

  4. Electrodialysis heterogeneous ion exchange membranes modified by SiO2 nanoparticles: fabrication and electrochemical characterization.

    PubMed

    Hosseini, S M; Ahmadi, Z; Nemati, M; Parvizian, F; Madaeni, S S

    2016-01-01

    In the current study mixed matrix heterogeneous cation exchange membranes were prepared by solution casting technique. The effect of SiO(2) nanoparticles in the polymeric solution on the physicochemical properties of prepared membranes was studied. Scanning optical microscope images showed uniform particle distribution and relatively uniform surfaces for the prepared membranes. The membrane water content was reduced by silica nanoparticles in the membranes' matrix. The membrane ion exchange capacity, membrane potential, transport number and selectivity were improved initially by an increase of SiO(2) nanoparticles concentration up to 1%wt in prepared membranes and then showed a decreasing trend with a further increase in additive ratio from 1 to 4%wt. The ionic permeability and flux were also decreased initially by an increase of silica nanoparticles concentration up to 0.5%wt in the membrane matrix and then increased again with a further increase in nanoparticles concentration from 0.5 to 4%wt. Moreover, the results exhibited that using silica nanoparticles in the membrane matrix caused an obvious decrease in areal electrical resistance. The opposite trend was found for membrane mechanical strength using SiO(2) nanoparticles. PMID:27148708

  5. Electrodialysis heterogeneous ion exchange membranes modified by SiO2 nanoparticles: fabrication and electrochemical characterization.

    PubMed

    Hosseini, S M; Ahmadi, Z; Nemati, M; Parvizian, F; Madaeni, S S

    2016-01-01

    In the current study mixed matrix heterogeneous cation exchange membranes were prepared by solution casting technique. The effect of SiO(2) nanoparticles in the polymeric solution on the physicochemical properties of prepared membranes was studied. Scanning optical microscope images showed uniform particle distribution and relatively uniform surfaces for the prepared membranes. The membrane water content was reduced by silica nanoparticles in the membranes' matrix. The membrane ion exchange capacity, membrane potential, transport number and selectivity were improved initially by an increase of SiO(2) nanoparticles concentration up to 1%wt in prepared membranes and then showed a decreasing trend with a further increase in additive ratio from 1 to 4%wt. The ionic permeability and flux were also decreased initially by an increase of silica nanoparticles concentration up to 0.5%wt in the membrane matrix and then increased again with a further increase in nanoparticles concentration from 0.5 to 4%wt. Moreover, the results exhibited that using silica nanoparticles in the membrane matrix caused an obvious decrease in areal electrical resistance. The opposite trend was found for membrane mechanical strength using SiO(2) nanoparticles.

  6. Ionic α-Helical Polypeptides towards Non-Viral Gene Delivery

    PubMed Central

    Zhang, Rujing; Song, Ziyuan; Yin, Lichen; Zheng, Nan; Tang, Haoyu; Lu, Hua; Gabrielson, Nathan P.; Lin, Yao; Kim, Kyung; Cheng, Jianjun

    2014-01-01

    The advent of polymeric materials has significantly promoted the development and rapid growth of various technologies in biomedical applications, such as tissue engineering and controlled drug and gene delivery. Water-soluble polypeptides bearing functional side chains and adopting stable secondary structures are a new class of functional polymeric materials of potentially broad applications in medicine and biotechnology. In this article, we summarize our recent effort on the design and synthesis of the water-soluble α-helical ionic polypeptides originally developed in our laboratory and highlight their applications in cell membrane penetration and non-viral gene/siRNA delivery. PMID:25377262

  7. Polymerization in emulsion microdroplet reactors

    NASA Astrophysics Data System (ADS)

    Carroll, Nick J.

    The goal of this research project is to utilize emulsion droplets as chemical reactors for execution of complex polymerization chemistries to develop unique and functional particle materials. Emulsions are dispersions of immiscible fluids where one fluid usually exists in the form of drops. Not surprisingly, if a liquid-to-solid chemical reaction proceeds to completion within these drops, the resultant solid particles will possess the shape and relative size distribution of the drops. The two immiscible liquid phases required for emulsion polymerization provide unique and complex chemical and physical environments suitable for the engineering of novel materials. The development of novel non-ionic fluorosurfactants allows fluorocarbon oils to be used as the continuous phase in a water-free emulsion. Such emulsions enable the encapsulation of almost any hydrocarbon compound in droplets that may be used as separate compartments for water-sensitive syntheses. Here, we exemplify the promise of this approach by suspension polymerization of polyurethanes (PU), in which the liquid precursor is emulsified into droplets that are then converted 1:1 into polymer particles. The stability of the droplets against coalescence upon removal of the continuous phase by evaporation confirms the formation of solid PU particles. These results prove that the water-free environment of fluorocarbon based emulsions enables high conversion. We produce monodisperse, cross-linked, and fluorescently labeled PU-latexes with controllable mesh size through microfluidic emulsification in a simple one-step process. A novel method for the fabrication of monodisperse mesoporous silica particles is presented. It is based on the formation of well-defined equally sized emulsion droplets using a microfluidic approach. The droplets contain the silica precursor/surfactant solution and are suspended in hexadecane as the continuous oil phase. The solvent is then expelled from the droplets, leading to

  8. Electrodeposition in Ionic Liquids.

    PubMed

    Zhang, Qinqin; Wang, Qian; Zhang, Suojiang; Lu, Xingmei; Zhang, Xiangping

    2016-02-01

    Due to their attractive physico-chemical properties, ionic liquids (ILs) are increasingly used as deposition electrolytes. This review summarizes recent advances in electrodeposition in ILs and focuses on its similarities and differences with that in aqueous solutions. The electrodeposition in ILs is divided into direct and template-assisted deposition. We detail the direct deposition of metals, alloys and semiconductors in five types of ILs, including halometallate ILs, air- and water-stable ILs, deep eutectic solvents (DESs), ILs with metal-containing cations, and protic ILs. Template-assisted deposition of nanostructures and macroporous structures in ILs is also presented. The effects of modulating factors such as deposition conditions (current density, current density mode, deposition time, temperature) and electrolyte components (cation, anion, metal salts, additives, water content) on the morphology, compositions, microstructures and properties of the prepared materials are highlighted.

  9. Noble metal ionic catalysts.

    PubMed

    Hegde, M S; Madras, Giridhar; Patil, K C

    2009-06-16

    Because of growing environmental concerns and increasingly stringent regulations governing auto emissions, new more efficient exhaust catalysts are needed to reduce the amount of pollutants released from internal combustion engines. To accomplish this goal, the major pollutants in exhaust-CO, NO(x), and unburned hydrocarbons-need to be fully converted to CO(2), N(2), and H(2)O. Most exhaust catalysts contain nanocrystalline noble metals (Pt, Pd, Rh) dispersed on oxide supports such as Al(2)O(3) or SiO(2) promoted by CeO(2). However, in conventional catalysts, only the surface atoms of the noble metal particles serve as adsorption sites, and even in 4-6 nm metal particles, only 1/4 to 1/5 of the total noble metal atoms are utilized for catalytic conversion. The complete dispersion of noble metals can be achieved only as ions within an oxide support. In this Account, we describe a novel solution to this dispersion problem: a new solution combustion method for synthesizing dispersed noble metal ionic catalysts. We have synthesized nanocrystalline, single-phase Ce(1-x)M(x)O(2-delta) and Ce(1-x-y)Ti(y)M(x)O(2-delta) (M = Pt, Pd, Rh; x = 0.01-0.02, delta approximately x, y = 0.15-0.25) oxides in fluorite structure. In these oxide catalysts, Pt(2+), Pd(2+), or Rh(3+) ions are substituted only to the extent of 1-2% of Ce(4+) ion. Lower-valent noble metal ion substitution in CeO(2) creates oxygen vacancies. Reducing molecules (CO, H(2), NH(3)) are adsorbed onto electron-deficient noble metal ions, while oxidizing (O(2), NO) molecules are absorbed onto electron-rich oxide ion vacancy sites. The rates of CO and hydrocarbon oxidation and NO(x) reduction (with >80% N(2) selectivity) are 15-30 times higher in the presence of these ionic catalysts than when the same amount of noble metal loaded on an oxide support is used. Catalysts with palladium ion dispersed in CeO(2) or Ce(1-x)Ti(x)O(2) were far superior to Pt or Rh ionic catalysts. Therefore, we have demonstrated that the

  10. Removal of charged micropollutants from water by ion-exchange polymers -- effects of competing electrolytes.

    PubMed

    Bäuerlein, Patrick S; Ter Laak, Thomas L; Hofman-Caris, Roberta C H M; de Voogt, Pim; Droge, Steven T J

    2012-10-15

    A wide variety of environmental compounds of concern, e.g. pharmaceuticals or illicit drugs, are acids or bases that may predominantly be present as charged species in drinking water sources. These charged micropollutants may prove difficult to remove by currently used water treatment steps (e.g. UV/H(2)O(2), activated carbon (AC) or membranes). We studied the sorption affinity of some ionic organic compounds to both AC and different charged polymeric materials. Ion-exchange polymers may be effective as additional extraction phases in water treatment, because sorption of all charged compounds to oppositely charged polymers was stronger than to AC, especially for the double-charged cation metformin. Tested below 1% of the polymer ion-exchange capacity, the sorption affinity of charged micropollutants is nonlinear and depends on the composition of the aqueous medium. Whereas oppositely charged electrolytes do not impact sorption of organic ions, equally charged electrolytes do influence sorption indicating ion-exchange (IE) to be the main sorption mechanism. For the tested polymers, a tenfold increased salt concentration lowered the IE-sorption affinity by a factor two. Different electrolytes affect IE with organic ions in a similar way as inorganic ions on IE-resins, and no clear differences in this trend were observed between the sulphonated and the carboxylated cation-exchanger. Sorption of organic cations is five fold less in Ca(2+) solutions compared to similar concentrations of Na(+), while that of anionic compounds is three fold weaker in SO(4)(2-) solutions compared to equal concentrations of Cl(-). PMID:22818952

  11. Ionic dependence of sulphur mustard cytotoxicity

    SciTech Connect

    Sawyer, Thomas W. Nelson, Peggy; Bjarnason, Stephen; Vair, Cory; Shei Yimin; Tenn, Catherine; Lecavalier, Pierre; Burczyk, Andrew

    2010-09-15

    The effect of ionic environment on sulphur mustard (bis 2-chloroethyl sulphide; HD) toxicity was examined in CHO-K1 cells. Cultures were treated with HD in different ionic environments at constant osmolar conditions (320 mOsM, pH 7.4). The cultures were refed with fresh culture medium 1 h after HD exposure, and viability was assessed. Little toxicity was apparent when HD exposures were carried out in ion-free sucrose buffer compared to LC{sub 50} values of {approx} 100-150 {mu}M when the cultures were treated with HD in culture medium. Addition of NaCl to the buffer increased HD toxicity in a salt concentration-dependent manner to values similar to those obtained in culture medium. HD toxicity was dependent on both cationic and anionic species with anionic environment playing a much larger role in determining toxicity. Substitution of NaI for NaCl in the treatment buffers increased HD toxicity by over 1000%. The activity of the sodium hydrogen exchanger (NHE) in recovering from cytosolic acidification in salt-free and in different chloride salts did not correlate with the HD-induced toxicity in these buffers. However, the inhibition by HD of intracellular pH regulation correlated with its toxicity in NaCl, NaI and sucrose buffers. Analytical chemical studies and the toxicity of the iodine mustard derivative ruled out the role of chemical reactions yielding differentially toxic species as being responsible for the differences in HD toxicity observed. This work demonstrates that the early events that HD sets into motion to cause toxicity are dependent on ionic environment, possibly due to intracellular pH deregulation.

  12. Novel functionalized fluorescent polymeric nanoparticles for immobilization of biomolecules

    NASA Astrophysics Data System (ADS)

    Jain, Swati; Chattopadhyay, Sruti; Jackeray, Richa; Abid, C. K. V. Zainul; Singh, Harpal

    2013-07-01

    Novel, size controlled fluorescent polymeric nanoparticles (FPNP) were synthesized having acetoacetoxy functionality on the surface for immobilization of biomolecules which can be utilized as biomarkers and labels in fluoroimmunoassays. Core-shell nanoparticles of poly(styrene, St-methyl methacrylate, MMA-acetoacetoxy ethyl methacrylate, AAEM), stabilized by various concentrations of surfactant, sodium lauryl sulphate (SLS), were obtained by facile miniemulsion co-polymerization encapsulated with pyrene molecules in their hydrophobic core. Analytical, spectroscopic and imaging characterization techniques revealed the formation of stable, monodisperse, spherical nano sized particles exhibiting high luminescence properties. Particles with 1% SLS (S1) showed good dispersion stability and fluorescence intensity and were chosen as ideal candidates for further immobilization studies. Steady state fluorescence studies showed 10 times higher fluorescence intensity of S1 nanoparticles than that of pyrene solution in solvent-toluene at the same concentration. Environmental factors such as pH, ionic strength and time were found to have no effect on fluorescence intensity of FPNPs. Surface β-di-ketone groups were utilized for the covalent immobilization of enzyme conjugated antibodies without any activation or pre-treatment of nanoparticles.Novel, size controlled fluorescent polymeric nanoparticles (FPNP) were synthesized having acetoacetoxy functionality on the surface for immobilization of biomolecules which can be utilized as biomarkers and labels in fluoroimmunoassays. Core-shell nanoparticles of poly(styrene, St-methyl methacrylate, MMA-acetoacetoxy ethyl methacrylate, AAEM), stabilized by various concentrations of surfactant, sodium lauryl sulphate (SLS), were obtained by facile miniemulsion co-polymerization encapsulated with pyrene molecules in their hydrophobic core. Analytical, spectroscopic and imaging characterization techniques revealed the formation of stable

  13. Investigation of Four Different Laponite Clays as Stabilizers in Pickering Emulsion Polymerization.

    PubMed

    Brunier, Barthélémy; Sheibat-Othman, Nida; Chniguir, Mehdi; Chevalier, Yves; Bourgeat-Lami, Elodie

    2016-06-21

    Clay-armored polymer particles were prepared by emulsion polymerization in the presence of Laponite platelets that adsorb at the surface of latex particles and act as stabilizers during the course of the polymerization. While Laponite RDS clay platelets are most often used, the choice of the type of clay still remains an open issue that is addressed in the present article. Four different grades of Laponite were investigated as stabilizers in the emulsion polymerization of styrene. First, the adsorption isotherms of the clays, on preformed polystyrene particles, were determined by ICP-AES analysis of the residual clay in the aqueous phase. Adsorption of clay depended on the type of clay at low concentrations corresponding to adsorption as a monolayer. Adsorption of clay particles as multilayers was observed for all the grades above a certain concentration under the considered ionic strength (mainly due to the initiator ionic species). The stabilization efficiency of these clays was investigated during the polymerization reaction (free of any other stabilizer). The clays did not have the same effect on stabilization, which was related to differences in their compositions and in their adsorption isotherms. The different grades led to different polymer particles sizes and therefore to different polymerization reaction rates. Laponite RDS and S482 gave similar results, ensuring the best stabilization efficiency and the fastest reaction rate; the number of particles increased as the clay concentration increased. Stabilization with Laponite XLS gave the same particles size and number as the latter two clays at low clay concentrations, but it reached an upper limit in the number of nucleated polymer particles at higher concentrations indicating a decrease of stabilization efficiency at high concentrations. Laponite JS did not ensure a sufficient stability of the polymer particles, as the polymerization results were comparable to a stabilizer-free polymerization system.

  14. Hydrogen bonding in ionic liquids.

    PubMed

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

    2015-03-01

    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

  15. Production of monodisperse, polymeric microspheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Rhim, Won-Kyu (Inventor); Hyson, Michael T. (Inventor); Chang, Manchium (Inventor)

    1990-01-01

    Very small, individual polymeric microspheres with very precise size and a wide variation in monomer type and properties are produced by deploying a precisely formed liquid monomer droplet, suitably an acrylic compound such as hydroxyethyl methacrylate into a containerless environment. The droplet which assumes a spheroid shape is subjected to polymerizing radiation such as ultraviolet or gamma radiation as it travels through the environment. Polymeric microspheres having precise diameters varying no more than plus or minus 5 percent from an average size are recovered. Many types of fillers including magnetic fillers may be dispersed in the liquid droplet.

  16. Organometallic Polymeric Conductors

    NASA Technical Reports Server (NTRS)

    Youngs, Wiley J.

    1997-01-01

    For aerospace applications, the use of polymers can result in tremendous weight savings over metals. Suitable polymeric materials for some applications like EMI shielding, spacecraft grounding, and charge dissipation must combine high electrical conductivity with long-term environmental stability, good processability, and good mechanical properties. Recently, other investigators have reported hybrid films made from an electrically conductive polymer combined with insulating polymers. In all of these instances, the films were prepared by infiltrating an insulating polymer with a precursor for a conductive polymer (either polypyrrole or polythiophene), and oxidatively polymerizing the precursor in situ. The resulting composite films have good electrical conductivity, while overcoming the brittleness inherent in most conductive polymers. Many aerospace applications require a combination of properties. Thus, hybrid films made from polyimides or other engineering resins are of primary interest, but only if conductivities on the same order as those obtained with a polystyrene base could be obtained. Hence, a series of experiments was performed to optimize the conductivity of polyimide-based composite films. The polyimide base chosen for this study was Kapton. 3-MethylThiophene (3MT) was used for the conductive phase. Three processing variables were identified for producing these composite films, namely time, temperature, and oxidant concentration for the in situ oxidation. Statistically designed experiments were used to examine the effects of these variables and synergistic/interactive effects among variables on the electrical conductivity and mechanical strength of the films. Multiple linear regression analysis of the tensile data revealed that temperature and time have the greatest effect on maximum stress. The response surface of maximum stress vs. temperature and time (for oxidant concentration at 1.2 M) is shown. Conductivity of the composite films was measured for

  17. Fabrication of Poly(methyl Methacrylate) microfluidic chips by redox-initiated polymerization

    SciTech Connect

    Chen, Jiang; Lin, Yuehe; Chen, Gang

    2007-08-16

    In this report, a method based on the redox-initiated polymerization of methyl methacrylate (MMA) has been developed for the rapid fabrication of PMMA microfluidic chips.The new fabrication approach obviates the need for special equipment and significantly simplifies the process of fabricating microdevices. The attractive performance of the novel PMMA microchips has been demonstrated in connection with contactless conductivity detection for the separation and detection of ionic species.

  18. Chiral discrimination by ionic liquids: impact of ionic solutes.

    PubMed

    Brown, Christopher J; Hopkins, Todd A

    2015-04-01

    Chiral ionic liquids hold promise in many asymmetric applications. This study explores the impact of ionic solutes on the chiral discrimination of five amino acid methyl ester-based ionic liquids, including L- and D-alanine methyl ester, L-proline methyl ester, L-leucine methyl ester, and L-valine methyl ester cations combined with bis(trifluoromethanesulfonimide) anion. Circularly polarized luminescence spectroscopy was used to study the chiral discrimination by measuring the racemization equilibrium of a dissymmetric europium complex, Eu(dpa)3(3-) (where dpa = 2,6-pyridinedicarboxylate). The chiral discrimination measured was dependent on the concentration of Eu(dpa)3(3-) and this concentration-dependence was different in each of the ionic liquids. Ionic liquids with L-leucine methyl ester and L-valine methyl ester even switched enantiomeric preference based on the solute concentration. Changing the cation of the Eu(dpa)3(3-) salt from tetrabutylammonium to tetramethylammonium ion also affected the chiral discrimination demonstrated by the ionic liquids.

  19. Low-noise polymeric nanomechanical biosensors

    NASA Astrophysics Data System (ADS)

    Calleja, Montserrat; Tamayo, Javier; Nordström, Maria; Boisen, Anja

    2006-03-01

    A sensor device based on a single polymer cantilever and optical readout has been developed for detection of molecular recognition reactions without the need of a reference cantilever for subtraction of unspecific signals. Microcantilevers have been fabricated in the photoresist SU-8 with one surface passivated with a thin fluorocarbon layer. The SU-8 surface is sensitized with biological receptors by applying silanization methods, whereas the fluorocarbon surface remains inert to these processes. The thermal and mechanical properties of the chosen materials allow overcoming the main limitations of gold-coated silicon cantilevers: the temperature, pH, and ionic strength cross sensitivities. This is demonstrated by comparing the response of SU-8 cantilevers and that of gold-coated silicon nitride cantilevers to variations in temperature and pH. The sensitivity of the developed polymeric nanomechanical sensor is demonstrated by real-time detection of the human growth hormone with sensitivity in differential surface stress of about 1mN /m.

  20. Influence of the ionic liquid cation on the solvent extraction of trivalent rare-earth ions by mixtures of Cyanex 923 and ionic liquids.

    PubMed

    Rout, Alok; Binnemans, Koen

    2015-01-21

    Trivalent rare-earth ions were extracted from nitric acid medium by the neutral phosphine oxide extractant Cyanex 923 into ionic liquid phases containing the bis(trifluoromethylsulfonyl)imide anion. Five different cations were considered: 1-butyl-3-methylimidazolium, 1-decyl-3-methylimidazolium, methyltributylammonium, methyltrioctylammonium and trihexyl(tetradecyl)phosphonium. The extraction behavior of neodymium(iii) was investigated as a function of various parameters: pH, extractant concentration, concentration of the neodymium(iii) ion in the aqueous feed and concentration of the salting-out agent. The loading capacity of the ionic liquid phase was studied. The extraction efficiency increased with increasing pH of the aqueous feed solution. The extraction occurred for all ionic liquids via an ion-exchange mechanism and the extraction efficiency could be related to the solubility of the ionic liquid cation in the aqueous phase: high distribution ratios for hydrophilic cations and low ones for hydrophobic cations. Addition of nitrate ions to the aqueous phase resulted in an increase in extraction efficiency for ionic liquids with hydrophobic cations due to extraction of neutral complexes. Neodymium(iii) could be stripped from the ionic liquid phase by 0.5-1.0 M nitric acid solutions and the extracting phase could be reused. The extractability of other rare earths present in the mixture was compared for the five ionic liquids.

  1. Redox-active cross-linkable poly(ionic liquid)s.

    PubMed

    Sui, Xiaofeng; Hempenius, Mark A; Vancso, G Julius

    2012-03-01

    The synthesis of a new class of cross-linkable redox-responsive poly(ferrocenylsilane)-based poly(ionic liquid)s (PFS-PILs) is reported. PFS-PILs self-cross-link at low concentrations into nanogels or form macroscopic hydrogel networks at higher concentrations. PFS-PILs proved to be efficient dispersants in the microemulsion polymerization of methyl methacrylate, producing stable PFS-poly(methyl methacrylate) latex suspensions. PMID:22353019

  2. Design of Self-Healing Supramolecular Rubbers by Introducing Ionic Cross-Links into Natural Rubber via a Controlled Vulcanization.

    PubMed

    Xu, Chuanhui; Cao, Liming; Lin, Baofeng; Liang, Xingquan; Chen, Yukun

    2016-07-13

    Introducing ionic associations is one of the most effective approaches to realize a self-healing behavior for rubbers. However, most of commercial rubbers are nonpolar rubbers without now available functional groups to be converted into ionic groups. In this paper, our strategy was based on a controlled peroxide-induced vulcanization to generate massive ionic cross-links via polymerization of zinc dimethacrylate (ZDMA) in natural rubber (NR) and exploited it as a potential self-healable material. We controlled vulcanization process to retard the formation of covalent cross-link network, and successfully generated a reversible supramolecular network mainly constructed by ionic cross-links. Without the restriction of covalent cross-linkings, the NR chains in ionic supramolecular network had good flexibility and mobility. The nature that the ionic cross-links was easily reconstructed and rearranged facilitating the self-healing behavior, thereby enabling a fully cut sample to rejoin and retain to its original properties after a suitable self-healing process at ambient temperature. This study thus demonstrates a feasible approach to impart an ionic association induced self-healing function to commercial rubbers without ionic functional groups.

  3. Design of Self-Healing Supramolecular Rubbers by Introducing Ionic Cross-Links into Natural Rubber via a Controlled Vulcanization.

    PubMed

    Xu, Chuanhui; Cao, Liming; Lin, Baofeng; Liang, Xingquan; Chen, Yukun

    2016-07-13

    Introducing ionic associations is one of the most effective approaches to realize a self-healing behavior for rubbers. However, most of commercial rubbers are nonpolar rubbers without now available functional groups to be converted into ionic groups. In this paper, our strategy was based on a controlled peroxide-induced vulcanization to generate massive ionic cross-links via polymerization of zinc dimethacrylate (ZDMA) in natural rubber (NR) and exploited it as a potential self-healable material. We controlled vulcanization process to retard the formation of covalent cross-link network, and successfully generated a reversible supramolecular network mainly constructed by ionic cross-links. Without the restriction of covalent cross-linkings, the NR chains in ionic supramolecular network had good flexibility and mobility. The nature that the ionic cross-links was easily reconstructed and rearranged facilitating the self-healing behavior, thereby enabling a fully cut sample to rejoin and retain to its original properties after a suitable self-healing process at ambient temperature. This study thus demonstrates a feasible approach to impart an ionic association induced self-healing function to commercial rubbers without ionic functional groups. PMID:27337545

  4. Kinetics of silica polymerization

    SciTech Connect

    Weres, O.; Yee, A.; Tsao, L.

    1980-05-01

    The polymerization of silicic acid in geothermal brine-like aqueous solutions to produce amorphous silica in colloidal form has been studied experimentally and theoretically. A large amount of high quality experimental data has been generated over the temperature rang 23 to 100{sup 0}C. Wide ranges of dissolved silica concentration, pH, and sodium chloride concentration were covered. The catalytic effects of fluoride and the reaction inhibiting effects of aluminum and boron were studied also. Two basic processes have been separately studied: the formation of new colloidal particles by the homogeneous nucleation process and the deposition of dissolved silica on pre-existing colloidal particles. A rigorous theory of the formation of colloidal particles of amorphous silica by homogeneous nucleation was developed. This theory employs the Lothe-Pound formalism, and is embodied in the computer code SILNUC which quantitatively models the homogeneous nucleation and growth of colloidal silica particles in more than enough detail for practical application. The theory and code were extensively used in planning the experimental work and analyzing the data produced. The code is now complete and running in its final form. It is capable of reproducing most of the experimental results to within experimental error. It is also capable of extrapolation to experimentally inaccessible conditions, i.e., high temperatures, rapidly varying temperature and pH, etc.

  5. Some novel polymeric nanocomposites.

    PubMed

    Mark, James E

    2006-12-01

    The nanocomposites described here all involve polymers and were chosen because they are already of commercial importance, show some promise of becoming so, or simply seem interesting. The field is so broad that some topics are mentioned only very briefly, and there is considerable emphasis on the polysiloxane nanocomposites studied by the author's research group. Some are typically prepared using techniques very similar to those used in the new sol-gel approach to ceramics, with either the polymer or the ceramic being the continuous phase. Other dispersed phases include particles responsive to an applied magnetic field, intercalated or exfoliated platelets obtained from clays, mica, or graphite, silsesquioxane nanocages, nanotubes, dual fillers, porous particles, spherical and ellipsoidal polymeric particles, and nanocatalysts. Also described are some typical studies involving theory or simulations on such particle reinforcement. Experiments on ceramics modified by dispersed polymers are equally interesting, but there is less relevant theory. Many of the fields mentioned have become so vast that the approach taken here is simply to describe general approaches and characteristics of the composites, list some specific examples, and provide leading references (with some emphasis on studies that are relatively recent or in the nature of reviews).

  6. Partitioning of Laponite Clay Platelets in Pickering Emulsion Polymerization.

    PubMed

    Brunier, Barthélémy; Sheibat-Othman, Nida; Chevalier, Yves; Bourgeat-Lami, Elodie

    2016-01-12

    Partitioning of laponite disklike clay platelets between polymer particles and bulk aqueous phase was investigated in Pickering surfactant-free emulsion polymerization of styrene. Adsorption of laponite clay platelets plays an important role in the stabilization of this system, influencing the particle size and the number of particles, and, hence, the reaction rate. Adsorption isotherms show that, while the laponite clay platelets are almost fully exfoliated in water, they form multilayers on the surface of the polymer particles by the end of polymerization, as confirmed by transmission electron microscopy (TEM). This observation is supported by quartz crystal microbalance, conductivity, and TEM measurements, which reveal interactions between the clay and polystyrene, as a function of the ionic strength. The strong adsorption of clay platelets leaves a low residual concentration in the aqueous phase that cannot cause further nucleation of polymer particles, as demonstrated during seeded emulsion polymerization experiments in the presence of a high excess of clay. A Brunauer-Emmett-Teller (BET)-type model for laponite adsorption on polystyrene particles matches the adsorption isotherms.

  7. Fabrication of PMMA CE microchips by infrared-assisted polymerization.

    PubMed

    Chen, Yun; Duan, Haotian; Zhang, Luyan; Chen, Gang

    2008-12-01

    In this report, a method based on the infrared-assisted polymerization of methyl methacrylate has been developed for the rapid fabrication of PMMA CE microchips. Methyl methacrylate containing AIBN was allowed to prepolymerize in a water bath to form a fast-curing molding solution that was subsequently sandwiched between a silicon template and a piece of 1 mm-thick PMMA plate. The images of microchannels on the silicon template were precisely replicated into the synthesized PMMA substrates during the infrared-assisted polymerization of the molding solution. The polymerization could be completed within 50 min at 50 degrees C. The obtained channel plate was subsequently bonded to a piece of PMMA cover sheet to form a microchip with the aid of heat and pressure. The new fabrication approach obviates the need for special equipment and significantly simplifies the process of fabricating PMMA microchips. The attractive performance of the obtained PMMA microchips has been demonstrated in connection with contactless conductivity detection for the separation and detection of ionic species.

  8. Polymerization of anionic wormlike micelles.

    PubMed

    Zhu, Zhiyuan; González, Yamaira I; Xu, Hangxun; Kaler, Eric W; Liu, Shiyong

    2006-01-31

    Polymerizable anionic wormlike micelles are obtained upon mixing the hydrotropic salt p-toluidine hydrochloride (PTHC) with the reactive anionic surfactant sodium 4-(8-methacryloyloxyoctyl)oxybenzene sulfonate (MOBS). Polymerization captures the cross-sectional radius of the micelles (approximately 2 nm), induces micellar growth, and leads to the formation of a stable single-phase dispersion of wormlike micellar polymers. The unpolymerized and polymerized micelles were characterized using static and dynamic laser light scattering, small-angle neutron scattering, 1H NMR, and stopped-flow light scattering. Stopped-flow light scattering was also used to measure the average lifetime of the unpolymerized wormlike micelles. A comparison of the average lifetime of unpolymerized wormlike micelles with the surfactant monomer propagation rate was used to elucidate the mechanism of polymerization. There is a significant correlation between the ratio of the average lifetime to the monomer propagation rate and the average aggregation number of the polymerized wormlike micelles.

  9. Polymerization of anionic wormlike micelles.

    PubMed

    Zhu, Zhiyuan; González, Yamaira I; Xu, Hangxun; Kaler, Eric W; Liu, Shiyong

    2006-01-31

    Polymerizable anionic wormlike micelles are obtained upon mixing the hydrotropic salt p-toluidine hydrochloride (PTHC) with the reactive anionic surfactant sodium 4-(8-methacryloyloxyoctyl)oxybenzene sulfonate (MOBS). Polymerization captures the cross-sectional radius of the micelles (approximately 2 nm), induces micellar growth, and leads to the formation of a stable single-phase dispersion of wormlike micellar polymers. The unpolymerized and polymerized micelles were characterized using static and dynamic laser light scattering, small-angle neutron scattering, 1H NMR, and stopped-flow light scattering. Stopped-flow light scattering was also used to measure the average lifetime of the unpolymerized wormlike micelles. A comparison of the average lifetime of unpolymerized wormlike micelles with the surfactant monomer propagation rate was used to elucidate the mechanism of polymerization. There is a significant correlation between the ratio of the average lifetime to the monomer propagation rate and the average aggregation number of the polymerized wormlike micelles. PMID:16430253

  10. Non-ionic micelles and encapsulation.

    NASA Astrophysics Data System (ADS)

    Alexandridis, Paschalis

    2007-03-01

    The development of self-assembly as a useful approach to the synthesis and manufacturing of complex systems and materials is a central theme in our research. Amphiphilic block copolymers of the poly(ethylene oxide)-poly(propylene oxide) (PEO-PPO) family (commercially available as Poloxamers) are well-known for self-assembling into (core-shell spherical) micelles and (cubic, hexagonal, and lamellar) lyotropic liquid crystals in water. We are interested on how the aqueous phase behavior and structure of these non-ionic polymeric amphiphiles can be modulated by the addition of organic solvents or solutes. Our studies (i) probe the amphiphile organization in both micellar solutions and lyotropic liquid crystals, (ii) combine macroscopic observations (e.g., concentration-temperature micellization phase boundaries, ternary isothermal amphiphile-water-cosolvent phase diagrams) with microscopic measurements (from small-angle neutron and X-ray scattering), and (iii) aim to relate the type of structure formed and its properties to the relative swelling of the polymer blocks and to the location of the solvent/solute in the amphiphile assembly. These studies address the following practical questions: What are the ``right'' components and conditions for self-assembly? What if the conditions are no longer ``right''? How can we ``help'' self-assembly? Modulation of structure-property relationships in amphiphile-containing media is central to formulation of pharmaceutics and personal care products.

  11. Ionic Liquid Epoxy Resin Monomers

    NASA Technical Reports Server (NTRS)

    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.

  12. Ionic emission from Taylor cones

    NASA Astrophysics Data System (ADS)

    Castro Reina, Sergio

    Electrified Taylor cones have been seen as an efficient way to generate thrust for space propulsion. Especially the pure ionic regime (PIR) combines a very high specific impulse (thrust per unit mass) and efficiency, which is very important to reduce fuel transportation costs. The PIR has been primarily based on electrosprays of liquid metals [Swatik and Hendricks 1968, Swatik 1969]. However, emissions dominated by or containing exclusively ions have also been observed from nonmetallic purely ionic substances, initially sulfuric acid [Perel et al. 1969], and more recently room temperature molten salts referred to as ionic liquids (ILs) [Romero-Sanz et al. 2003]. The recent use of the liquid metal ion source (LMIS) with ILs, becoming this "new" source to be known as ionic liquid ion source (ILIS) [Lozano and Martinez-Sanchez 2005], has shown important differences on the emission from Taylor cones with the traditional hollow capillary. This new source seems to be more flexible than the capillary [Paulo, Sergio, carlos], although its low emission level (low thrust) is an important drawback from the space propulsion point of view. Throughout the thesis I have studied some aspects of the ionic emission from ionic liquid Taylor cones and the influence of the properties of the liquids and the characteristic of source on the emission. I have unraveled the reason why ILIS emits such low currents (˜200 nA) and found a way to solve this problem increasing the current up to capillary levels (˜1000 nA) [Castro and Fernandez de la Mora 2009]. I have also tried to reduce ion evaporation while reducing the emitted droplet size in order to increase the thrust generated while keeping the efficiency relatively high and I have measured the energy of evaporation of several cations composing ionic liquids, mandatory step to understand ionic evaporation.

  13. Hydrophobic ionic liquids

    DOEpatents

    Koch, Victor R.; Nanjundiah, Chenniah; Carlin, Richard T.

    1998-01-01

    Ionic liquids having improved properties for application in non-aqueous batteries, electrochemical capacitors, electroplating, catalysis and chemical separations are disclosed. Exemplary compounds have one of the following formulas: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, and R.sub.6 are either H; F; separate alkyl groups of from 1 to 4 carbon atoms, respectively, or joined together to constitute a unitary alkylene radical of from 2 to 4 carbon atoms forming a ring structure converging on N; or separate phenyl groups; and wherein the alkyl groups, alkylene radicals or phenyl groups may be substituted with electron withdrawing groups, preferably F--, Cl--, CF.sub.3 --, SF.sub.5 --, CF.sub.3 S--, (CF.sub.3).sub.2 CHS-- or (CF.sub.3).sub.3 CS--; and X.sup.- is a non-Lewis acid-containing polyatomic anion having a van der Waals volume exceeding 100 .ANG..sup.3.

  14. Hydrophobic ionic liquids

    DOEpatents

    Koch, V.R.; Nanjundiah, C.; Carlin, R.T.

    1998-10-27

    Ionic liquids having improved properties for application in non-aqueous batteries, electrochemical capacitors, electroplating, catalysis and chemical separations are disclosed. Exemplary compounds have one of the following formulas shown in a diagram wherein R{sub 1}, R{sub 2}, R{sub 3}, R{sub 4}, R{sub 5}, and R{sub 6} are either H; F; separate alkyl groups of from 1 to 4 carbon atoms, respectively, or joined together to constitute a unitary alkylene radical of from 2 to 4 carbon atoms forming a ring structure converging on N; or separate phenyl groups; and wherein the alkyl groups, alkylene radicals or phenyl groups may be substituted with electron withdrawing groups, preferably F-, Cl-, CF{sub 3}-, SF{sub 5}-, CF{sub 3}S-, (CF{sub 3}){sub 2}CHS- or (CF{sub 3}){sub 3}CS-; and X{sup {minus}} is a non-Lewis acid-containing polyatomic anion having a van der Waals volume exceeding 100 {angstrom}{sup 3}. 4 figs.

  15. Synthesis and characterization of polyacrylonitrile nanoparticles by dispersion/emulsion polymerization process.

    PubMed

    Boguslavsky, Lior; Baruch, Sigal; Margel, Shlomo

    2005-09-01

    Polyacrylonitrile nanoparticles in sizes ranging from approximately 35 to 270 nm were prepared by dispersion/emulsion polymerization of acrylonitrile in a continuous aqueous phase in the presence of potassium persulfate as initiator and various alkyl-sulfate and sulfonate surfactants. The influence of various polymerization parameters (e.g., concentration of monomer and initiator, type and concentration of surfactant, temperature and time of polymerization, ionic strength, pH and co-solvent concentration) on the properties (e.g., size and size distribution, yield, stability, etc.) of the particles has been investigated. The polymerization of acrylonitrile may occur in two major locations: in the aqueous continuous phase (dispersion polymerization) and/or within the surfactant micelles (emulsion polymerization). A discussion concerning the role of these two mechanisms under different conditions, including comparison with previous literature, is also presented. Surface and bulk characterizations of the particles were performed by methods such as transmission and scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, zeta potential, and gravimetric measurements. PMID:16009219

  16. Giant exchange interaction in mixed lanthanides

    PubMed Central

    Vieru, Veacheslav; Iwahara, Naoya; Ungur, Liviu; Chibotaru, Liviu F.

    2016-01-01

    Combining strong magnetic anisotropy with strong exchange interaction is a long standing goal in the design of quantum magnets. The lanthanide complexes, while exhibiting a very strong ionic anisotropy, usually display a weak exchange coupling, amounting to only a few wavenumbers. Recently, an isostructural series of mixed (Ln = Gd, Tb, Dy, Ho, Er) have been reported, in which the exchange splitting is estimated to reach hundreds wavenumbers. The microscopic mechanism governing the unusual exchange interaction in these compounds is revealed here by combining detailed modeling with density-functional theory and ab initio calculations. We find it to be basically kinetic and highly complex, involving non-negligible contributions up to seventh power of total angular momentum of each lanthanide site. The performed analysis also elucidates the origin of magnetization blocking in these compounds. Contrary to general expectations the latter is not always favored by strong exchange interaction. PMID:27087470

  17. Giant exchange interaction in mixed lanthanides

    NASA Astrophysics Data System (ADS)

    Vieru, Veacheslav; Iwahara, Naoya; Ungur, Liviu; Chibotaru, Liviu F.

    2016-04-01

    Combining strong magnetic anisotropy with strong exchange interaction is a long standing goal in the design of quantum magnets. The lanthanide complexes, while exhibiting a very strong ionic anisotropy, usually display a weak exchange coupling, amounting to only a few wavenumbers. Recently, an isostructural series of mixed (Ln = Gd, Tb, Dy, Ho, Er) have been reported, in which the exchange splitting is estimated to reach hundreds wavenumbers. The microscopic mechanism governing the unusual exchange interaction in these compounds is revealed here by combining detailed modeling with density-functional theory and ab initio calculations. We find it to be basically kinetic and highly complex, involving non-negligible contributions up to seventh power of total angular momentum of each lanthanide site. The performed analysis also elucidates the origin of magnetization blocking in these compounds. Contrary to general expectations the latter is not always favored by strong exchange interaction.

  18. Polymeric materials in Space

    NASA Astrophysics Data System (ADS)

    Skurat, Vladimir

    Paper of short review type. It is the continuation of and addition to previous review papers "V. E. Skurat. Polymers in Space. In: Encyclopedia of aerospace engineering, vol. 4, Wiley and sons, 2010; Ibid., 2012 (on line)". Following topics are considered: (1) Destruction of polymers by solar radiation with various wavelengths in different spectral regions (visible-UV, vacuum UV (VUV), deep UV, soft and hard X-rays) are discussed. In difference with common polymer photochemistry induced by UV radiation, directions of various routs of polymer phototransformations and their relative yields are greatly dependent on wavelength of light (photon energy) during illuminations in VUV, deep UV and X-ray regions. During last twenty years, intensive spacecraft investigations of solar spectrum show great periodic and spontaneous variations of radiation intensities in short-wavelengths regions - up to one - two decimal orders of magnitude for X-rays. As a result, during solar flares the absorbed dose on the polymer surfaces from X-rays can be compared with absorbed dose from VUV radiation. (2) Some new approaches to predictions of reaction efficiencies of fast orbital atomic oxygen in their interaction with polymeric materials are considered. (3) Some aspects of photocatalitic destruction of polymers in vacuum conditions by full-spectrum solar radiation are discussed. This process can take place in enamels containing semiconducting particles (TiO2, ZnO) as pigments. (4) Contamination of spacecraft surfaces from intrinsic outer atmosphere play important role not only from the point of view of deterioration of optical and thermophysical properties. Layers of SiO2 contaminations with nanometer thicknesses can greatly diminish mass losses from perfluorinated polymers under VUV irradiation.

  19. Polymeric materials for neovascularization

    NASA Astrophysics Data System (ADS)

    DeVolder, Ross John

    Revascularization therapies have emerged as a promising strategy to treat various acute and chronic wounds, cardiovascular diseases, and tissue defects. It is common to either administer proangiogenic growth factors, such as vascular endothelial growth factor (VEGF), or transplant cells that endogenously express multiple proangiogenic factors. Additionally, these strategies utilize a wide variety of polymeric systems, including hydrogels and biodegradable plastics, to deliver proangiogenic factors in a sophisticated manner to maintain a sustained proangiogenic environment. Despite some impressive results in rebuilding vascular networks, it is still a challenging task to engineer mature and functional neovessels in target tissues, because of the increasing complexities involved with neovascularization applications. To resolve these challenges, this work aims to design a wide variety of proangiogenic biomaterial systems with tunable properties used for neovascularization therapies. This thesis describes the design of several biomaterial systems used for the delivery of proangiogenic factors in neovascularization therapies, including: an electrospun/electrosprayed biodegradable plastic patch used for directional blood vessel growth (Chapter 2), an alginate-g-pyrrole hydrogel system that biochemically stimulates cellular endogenous proangiogenic factor expression (Chapter 3), an enzyme-catalyzed alginate-g-pyrrole hydrogel system for VEGF delivery (Chapter 4), an enzyme-activated alginate-g-pyrrole hydrogel system with systematically controllable electrical and mechanical properties (Chapter 5), and an alginate-g-pyrrole hydrogel that enables the decoupled control of electrical conductivity and mechanical rigidity and is use to electrically stimulate cellular endogenous proangiogenic factor expression (Chapter 6). Overall, the biomaterial systems developed in this thesis will be broadly useful for improving the quality of a wide array of molecular and cellular based

  20. HEAT EXCHANGER

    DOEpatents

    Fox, T.H. III; Richey, T. Jr.; Winders, G.R.

    1962-10-23

    A heat exchanger is designed for use in the transfer of heat between a radioactive fiuid and a non-radioactive fiuid. The exchanger employs a removable section containing the non-hazardous fluid extending into the section designed to contain the radioactive fluid. The removable section is provided with a construction to cancel out thermal stresses. The stationary section is pressurized to prevent leakage of the radioactive fiuid and to maintain a safe, desirable level for this fiuid. (AEC)

  1. Acrylate functionalized tetraalkylammonium salts with ionic liquid properties.

    PubMed

    Grothe, Dorian C; Meyer, Wolfdietrich; Janietz, Silvia

    2012-01-01

    Acrylate functionalized ionic liquids based on tetraalkylammonium salts with terminal acrylates- and methylacrylates were synthesized. Melting points and ionic conductivity of twenty compounds in six groups were determined. Within one group the effect of three different counterions was investigated and discussed. The groups differ in cationic structure elements because of their functional groups such as acrylate and methacrylate, alkyl residues at the nitrogen and number of quaternary ammonium atoms within the organic cation. The effect of these cationic structure elements has been examined concerning the compiled parameters with a view to qualifying them as components for solid state electrolytes. The newly synthesized ionic liquids were characterized by NMR and FTIR analysis. The exchange of halide ions like bromide as counter ions to weakly coordinating [PF₆]⁻, [OTf]⁻ or [TFSI]⁻ reduces the melting points significantly and leads to an ion conductivity of about 10⁻⁴ S/cm at room temperature. In the case of the dicationic ionic liquid, an ion conductivity of about 10⁻³ S/cm was observed.

  2. Mechanochemical solid-state polymerization. VIII. Novel composite polymeric prodrugs prepared by mechanochemical polymerization in the presence of pharmaceutical aids.

    PubMed

    Kondo, S; Hosaka, S; Kuzuya, M

    1998-04-01

    We carried out the mechanochemical polymerization of methacryloyl derivatives of acetoaminophen and 5-fluorouracil in the presence of lactose. The reaction proceeded readily and the polymeric prodrugs were quantitatively produced. This method produces powdered polymeric prodrugs in which fine particles of lactose are homogeneously dispersed, since the reaction proceeds quantitatively through a totally dry process. It is difficult to prepare such a powdered polymeric prodrug by conventional solution polymerization. The rate of drug release of polymeric prodrugs increases with increasing content of lactose, as is shown to be true of the specific surface of polymeric prodrugs. These results suggest that lactose is homogeneously dispersed in powdered polymeric prodrugs. The present method seems applicable to a wide variety of pharmaceutical aids. If one takes the physiochemical property of pharmaceutical aids into consideration, novel polymeric prodrugs with a variety of drug release rates can be synthesized simultaneously with mixing. PMID:9579043

  3. Dual Ionic and Organic Nature of Ionic Liquids

    PubMed Central

    Shi, Rui; Wang, Yanting

    2016-01-01

    Inherited the advantages of inorganic salts and organic solvents, ionic liquids (ILs) exhibit many superior properties allowing them promising green solvents for the future. Although it has been widely acknowledged that the unique features of ILs originate from their dual ionic and organic nature, its microscopic physical origin still remains blurry. In this work, by comparing the ion/molecule cage structures obtained from molecular dynamics simulations for seven prototypic liquids—a molten inorganic salt, four ILs, a strongly polar organic solvent, and a weakly polar organic solvent, we have revealed that the depth of the cage energy landscape characterizes the ionic nature of ILs, whereas the slope and curvature of its mimimum determine the organic nature of ILs. This finding advances our understanding of ILs and thus will help their efficient utilization as well as the systematic design of novel functionalized ILs. PMID:26782660

  4. Stereospecific olefin polymerization catalysts

    DOEpatents

    Bercaw, John E.; Herzog, Timothy A.

    1998-01-01

    A metallocene catalyst system for the polymerization of .alpha.-olefins to yield stereospecific polymers including syndiotactic, and isotactic polymers. The catalyst system includes a metal and a ligand of the formula ##STR1## wherein: R.sup.1, R.sup.2, and R.sup.3 are independently selected from the group consisting of hydrogen, C.sub.1 to C.sub.10 alkyl, 5 to 7 membered cycloalkyl, which in turn may have from 1 to 3 C.sub.1 to C.sub.10 alkyls as a substituent, C.sub.6 to C.sub.15 aryl or arylalkyl in which two adjacent radicals may together stand for cyclic groups having 4 to 15 carbon atoms which in turn may be substituted, or Si(R.sup.8).sub.3 where R.sup.8 is selected from the group consisting of C.sub.1 to C.sub.10 alkyl, C.sub.6 to C.sub.15 aryl or C.sub.3 to C.sub.10 cycloalkyl; R.sup.4 and R.sup.6 are substituents both having van der Waals radii larger than the van der Waals radii of groups R.sup.1 and R.sup.3 ; R.sup.5 is a substituent having a van der Waals radius less than about the van der Waals radius of a methyl group; E.sup.1, E.sup.2 are independently selected from the group consisting of Si(R.sup.9).sub.2, Si(R.sup.9).sub.2 --Si(R.sup.9).sub.2, Ge(R.sup.9).sub.2, Sn(R.sup.9).sub.2, C(R.sup.9).sub.2, C(R.sup.9).sub.2 --C(R.sup.9).sub.2, where R.sup.9 is C.sub.1 to C.sub.10 alkyl, C.sub.6 to C.sub.15 aryl or C.sub.3 to C.sub.10 cycloalkyl; and the ligand may have C.sub.S or C.sub.1 -symmetry. Preferred metals are selected from the group consisting of group III, group IV, group V or lanthanide group elements. The catalysts are used to prepare stereoregular polymers including polypropylene from .alpha.-olefin monomers.

  5. Stereospecific olefin polymerization catalysts

    DOEpatents

    Bercaw, J.E.; Herzog, T.A.

    1998-01-13

    A metallocene catalyst system is described for the polymerization of {alpha}-olefins to yield stereospecific polymers including syndiotactic, and isotactic polymers. The catalyst system includes a metal and a ligand of the formula shown wherein: R{sup 1}, R{sup 2}, and R{sup 3} are independently selected from the group consisting of hydrogen, C{sub 1} to C{sub 10} alkyl, 5 to 7 membered cycloalkyl, which in turn may have from 1 to 3 C{sub 1} to C{sub 10} alkyls as a substituent, C{sub 6} to C{sub 15} aryl or arylalkyl in which two adjacent radicals may together stand for cyclic groups having 4 to 15 carbon atoms which in turn may be substituted, or Si(R{sup 8}){sub 3} where R{sup 8} is selected from the group consisting of C{sub 1} to C{sub 10} alkyl, C{sub 6} to C{sub 15} aryl or C{sub 3} to C{sub 10} cycloalkyl; R{sup 4} and R{sup 6} are substituents both having van der Waals radii larger than the van der Waals radii of groups R{sup 1} and R{sup 3}; R{sup 5} is a substituent having a van der Waals radius less than about the van der Waals radius of a methyl group; E{sup 1}, E{sup 2} are independently selected from the group consisting of Si(R{sup 9}){sub 2}, Si(R{sup 9}){sub 2}--Si(R{sup 9}){sub 2}, Ge(R{sup 9}){sub 2}, Sn(R{sup 9}){sub 2}, C(R{sup 9}){sub 2}, C(R{sup 9}){sub 2}--C(R{sup 9}){sub 2}, where R{sup 9} is C{sub 1} to C{sub 10} alkyl, C{sub 6} to C{sub 15} aryl or C{sub 3} to C{sub 10} cycloalkyl; and the ligand may have C{sub S} or C{sub 1}-symmetry. Preferred metals are selected from the group consisting of group III, group IV, group V or lanthanide group elements. The catalysts are used to prepare stereoregular polymers including polypropylene from {alpha}-olefin monomers.

  6. Polymeric bicontinuous microemulsions

    NASA Astrophysics Data System (ADS)

    Krishnan, Kasiraman

    Rheology of complex fluids has been a topic of considerable interest recently. Bicontinuous microemulsions (BmuE), made by mixing appropriate amounts of oil, water and a surfactant, form a unique class of complex fluids. They possess a characteristic nanostructure consisting of undulating surfaces with vanishingly small interfacial curvature. BmuEs can also be generated in polymers by mixing appropriate amounts of two homopolymers and their corresponding diblock copolymer. The main objective of the present research is to study effects of shear on a model polymeric BmuE. Scattering is used as a predominant tool with in situ flow devices, along with optical microscopy and rheology. The model BmuE consists of a ternary blend of poly(ethyl ethylene) (PEE), poly(dimethyl siloxane) (PDMS) and a PEE-PDMS diblock copolymer. Steady shear experiments reveal four regimes as a function of shear rate. At low shear rates (regime I), Newtonian behavior is observed; there is onset of shear thinning at higher rates (regime II). In regime III, the stress is independent of shear rate, whereas it increases with shear rate once again in regime IV. Morphological characterization was carried out for each of these four regimes using scattering and microscopy, the key result being the evidence for flow-induced phase separation in regime III. Transient rheological measurements were conducted for startup and step changes in shear rate, and the BmuE exhibits features similar to worm-like micellar colloidal systems. Time-resolved light scattering and microscopy also reveal interesting characteristics. Dynamic mechanical spectroscopy indicates similarities with neat block copolymers near the order-disorder transition. The equilibrium rheological behavior is intriguing and detailed comparisons are made with Landau-Ginzburg theoretical models. Other areas of research as a part of this thesis include study of structural dynamics of BmuEs with dynamic light scattering, and the rheological

  7. Electronically and ionically conductive porous material and method for manufacture of resin wafers therefrom

    DOEpatents

    Lin, YuPo J.; Henry, Michael P.; Snyder, Seth W.

    2011-07-12

    An electrically and ionically conductive porous material including a thermoplastic binder and one or more of anion exchange moieties or cation exchange moieties or mixtures thereof and/or one or more of a protein capture resin and an electrically conductive material. The thermoplastic binder immobilizes the moieties with respect to each other but does not substantially coat the moieties and forms the electrically conductive porous material. A wafer of the material and a method of making the material and wafer are disclosed.

  8. Electronically and ionically conductive porous material and method for manufacture of resin wafers therefrom

    DOEpatents

    Lin, YuPo J.; Henry, Michael P.; Snyder, Seth W.

    2008-11-18

    An electrically and ionically conductive porous material including a thermoplastic binder and one or more of anion exchange moieties or cation exchange moieties or mixtures thereof and/or one or more of a protein capture resin and an electrically conductive material. The thermoplastic binder immobilizes the moieties with respect to each other but does not substantially coat the moieties and forms the electrically conductive porous material. A wafer of the material and a method of making the material and wafer are disclosed.

  9. 81891 - A New Class of Solvents for TRU Dissolution and Separation: Ionic Liquids

    SciTech Connect

    Robin D. Rogers

    2004-12-10

    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.

  10. Revisiting ether-derivatized imidazolium-based ionic liquids.

    PubMed

    Fei, Zhaofu; Ang, Wee Han; Zhao, Dongbin; Scopelliti, Rosario; Zvereva, Elena E; Katsyuba, Sergey A; Dyson, Paul J

    2007-08-30

    A series of ether-derivatized imidazolium halides have been prepared and characterized. Contrary to literature reports, they are all crystalline solids and have melting points well above room temperature (50-100 degrees C). Single crystals of the imidazolium salts, obtained in situ by slow cooling from their molten state to room temperature, were analyzed by X-ray crystallography, revealing various anion-cation interactions in the solid state. Exchange of the halides with [Tf(2)N]- yielded room temperature ionic liquids with viscosities that are comparable to related 1-alkyl-3-methylimidazolium ionic liquids. Density functional theory combined with IR spectroscopy has been used to analyze the role of functionalization of the imidazolium side chain on the formation of the molecular and supramolecular structure of the compounds and its possible impact on their physical properties. PMID:17676796

  11. Heat exchanger

    SciTech Connect

    Drury, C.R.

    1988-02-02

    A heat exchanger having primary and secondary conduits in heat-exchanging relationship is described comprising: at least one serpentine tube having parallel sections connected by reverse bends, the serpentine tube constituting one of the conduits; a group of open-ended tubes disposed adjacent to the parallel sections, the open-ended tubes constituting the other of the conduits, and forming a continuous mass of contacting tubes extending between and surrounding the serpentine tube sections; and means securing the mass of tubes together to form a predetermined cross-section of the entirety of the mass of open-ended tubes and tube sections.

  12. Preparation of molecularly imprinted polymers for strychnine by precipitation polymerization and multistep swelling and polymerization and their application for the selective extraction of strychnine from nux-vomica extract powder.

    PubMed

    Nakamura, Yukari; Matsunaga, Hisami; Haginaka, Jun

    2016-04-01

    Monodisperse molecularly imprinted polymers for strychnine were prepared by precipitation polymerization and multistep swelling and polymerization, respectively. In precipitation polymerization, methacrylic acid and divinylbenzene were used as a functional monomer and crosslinker, respectively, while in multistep swelling and polymerization, methacrylic acid and ethylene glycol dimethacrylate were used as a functional monomer and crosslinker, respectively. The retention and molecular recognition properties of the molecularly imprinted polymers prepared by both methods for strychnine were evaluated using a mixture of sodium phosphate buffer and acetonitrile as a mobile phase by liquid chromatography. In addition to shape recognition, ionic and hydrophobic interactions could affect the retention of strychnine in low acetonitrile content. Furthermore, molecularly imprinted polymers prepared by both methods could selectively recognize strychnine among solutes tested. The retention factors and imprinting factors of strychnine on the molecularly imprinted polymer prepared by precipitation polymerization were 220 and 58, respectively, using 20 mM sodium phosphate buffer (pH 6.0)/acetonitrile (50:50, v/v) as a mobile phase, and those on the molecularly imprinted polymer prepared by multistep swelling and polymerization were 73 and 4.5. These results indicate that precipitation polymerization is suitable for the preparation of a molecularly imprinted polymer for strychnine. Furthermore, the molecularly imprinted polymer could be successfully applied for selective extraction of strychnine in nux-vomica extract powder.

  13. On-demand photoinitiated polymerization

    SciTech Connect

    Boydston, Andrew J; Grubbs, Robert H; Daeffler, Chris; Momcilovic, Nebojsa

    2013-12-10

    Compositions and methods for adjustable lenses are provided. In some embodiments, the lenses contain a lens matrix material, a masking compound, and a prepolymer. The lens matrix material provides structure to the lens. The masking compound is capable of blocking polymerization or crosslinking of the prepolymer, until photoisomerization of the compound is triggered, and the compound is converted from a first isomer to a second isomer having a different absorption profile. The prepolymer is a composition that can undergo a polymerization or crosslinking reaction upon photoinitiation to alter one or more of the properties of the lenses.

  14. On-demand photoinitiated polymerization

    SciTech Connect

    Boydston, Andrew J; Grubbs, Robert H; Daeffler, Chris; Momcilovic, Nebojsa

    2015-01-13

    Compositions and methods for adjustable lenses are provided. In some embodiments, the lenses contain a lens matrix material, a masking compound, and a prepolymer. The lens matrix material provides structure to the lens. The masking compound is capable of blocking polymerization or crosslinking of the prepolymer, until photoisomerization of the compound is triggered, and the compound is converted from a first isomer to a second isomer having a different absorption profile. The prepolymer is a composition that can undergo a polymerization or crosslinking reaction upon photoinitiation to alter one or more of the properties of the lenses.

  15. Ionic Functionalization of Hydrophobic Colloidal Nanoparticles To Form Ionic Nanoparticles with Enzymelike Properties.

    PubMed

    Liu, Yuan; Purich, Daniel L; Wu, Cuichen; Wu, Yuan; Chen, Tao; Cui, Cheng; Zhang, Liqin; Cansiz, Sena; Hou, Weijia; Wang, Yanyue; Yang, Shengyuan; Tan, Weihong

    2015-12-01

    Inorganic colloidal nanoparticles (NPs) stabilized by a layer of hydrophobic surfactant on their surfaces have poor solubility in the aqueous phase, thus limiting their application as biosensors under physiological conditions. Here we report a simple model to ionize various types of hydrophobic colloidal NPs, including FePt, cubic Fe3O4, Pd, CdSe, and NaYF4 (Yb 30%, Er 2%, Nd 1%) NPs, to multicharged (positive and negative) NPs via ligand exchange. Surfaces of neutral hydrophobic NPs were converted to multicharged ions, thus making them soluble in water. Furthermore, peroxidase-like activity was observed for ionic FePt, Fe3O4, Pd, and CdSe NPs, of which FePt and CdSe catalyzed the oxidation of the colorless substrate 3,3',5,5'-tetramethylbenzidine (TMB) to the blue-colored product in the absence of H2O2, while Pd and Fe3O4 catalyzed the oxidization of TMB in the presence of H2O2. With the benefit of the ionic functionalization protocols described herein, colloidal NPs should gain wider use as biomarkers, nanozymes, and biosensors.

  16. Lithium ion conducting ionic electrolytes

    DOEpatents

    Angell, C. Austen; Xu, Kang; Liu, Changle

    1996-01-01

    A liquid, predominantly lithium-conducting, ionic electrolyte is described which has exceptionally high conductivity at temperatures of 100.degree. C. or lower, including room temperature. It comprises molten lithium salts or salt mixtures in which a small amount of an anionic polymer lithium salt is dissolved to stabilize the liquid against recrystallization. Further, a liquid ionic electrolyte which has been rubberized by addition of an extra proportion of anionic polymer, and which has good chemical and electrochemical stability, is described. This presents an attractive alternative to conventional salt-in-polymer electrolytes which are not cationic conductors.

  17. Lithium ion conducting ionic electrolytes

    DOEpatents

    Angell, C.A.; Xu, K.; Liu, C.

    1996-01-16

    A liquid, predominantly lithium-conducting, ionic electrolyte is described which has exceptionally high conductivity at temperatures of 100 C or lower, including room temperature. It comprises molten lithium salts or salt mixtures in which a small amount of an anionic polymer lithium salt is dissolved to stabilize the liquid against recrystallization. Further, a liquid ionic electrolyte which has been rubberized by addition of an extra proportion of anionic polymer, and which has good chemical and electrochemical stability, is described. This presents an attractive alternative to conventional salt-in-polymer electrolytes which are not cationic conductors. 4 figs.

  18. Influence of chemical microstructure of single-ion polymeric electrolyte membranes on performance of lithium-ion batteries.

    PubMed

    Zhang, Yunfeng; Rohan, Rupesh; Cai, Weiwei; Xu, Guodong; Sun, Yubao; Lin, An; Cheng, Hansong

    2014-10-22

    A novel protocol to generate and control porosity in polymeric structures is presented for fabrication of single ion polymer electrolyte (SIPE) membranes for lithium ion batteries. A series of SIPEs with varying ratios of aliphatic and aromatic segments was successfully synthesized and subsequently blended with PVDF-HFP to fabricate membranes of various sizes of pores. The membranes were characterized using techniques including SEM, solvent uptake capacity measurement and ionic conductivity. We demonstrate that appropriate membrane porosity enhances ionic conductivity, reduces interfacial resistance between electrodes and electrolyte and ultimately boosts performance of Li-ion batteries. The implication of the structure-performance relationship for battery design is discussed.

  19. High-modulus, high-conductivity nanostructured polymer electrolyte membranes via polymerization-induced phase separation.

    PubMed

    Schulze, Morgan W; McIntosh, Lucas D; Hillmyer, Marc A; Lodge, Timothy P

    2014-01-01

    The primary challenge in solid-state polymer electrolyte membranes (PEMs) is to enhance properties, such as modulus, toughness, and high temperature stability, without sacrificing ionic conductivity. We report a remarkably facile one-pot synthetic strategy based on polymerization-induced phase separation (PIPS) to generate nanostructured PEMs that exhibit an unprecedented combination of high modulus and ionic conductivity. Simple heating of a poly(ethylene oxide) macromolecular chain transfer agent dissolved in a mixture of ionic liquid, styrene and divinylbenzene, leads to a bicontinuous PEM comprising interpenetrating nanodomains of highly cross-linked polystyrene and poly(ethylene oxide)/ionic liquid. Ionic conductivities higher than the 1 mS/cm benchmark were achieved in samples with an elastic modulus approaching 1 GPa at room temperature. Crucially, these samples are robust solids above 100 °C, where the conductivity is significantly higher. This strategy holds tremendous potential to advance lithium-ion battery technology by enabling the use of lithium metal anodes or to serve as membranes in high-temperature fuel cells.

  20. Alkali oxide-tantalum, niobium and antimony oxide ionic conductors

    NASA Technical Reports Server (NTRS)

    Roth, R. S.; Brower, W. S.; Parker, H. S.; Minor, D. B.; Waring, J. L.

    1975-01-01

    The phase equilibrium relations of four systems were investigated in detail. These consisted of sodium and potassium antimonates with antimony oxide and tantalum and niobium oxide with rubidium oxide as far as the ratio 4Rb2O:llB2O5 (B=Nb, Ta). The ternary system NaSbO3-Sb2O4-NaF was investigated extensively to determine the actual composition of the body centered cubic sodium antimonate. Various other binary and ternary oxide systems involving alkali oxides were examined in lesser detail. The phases synthesized were screened by ion exchange methods to determine mobility of the mobility of the alkali ion within the niobium, tantalum or antimony oxide (fluoride) structural framework. Five structure types warranted further investigation; these structure types are (1) hexagonal tungsten bronze (HTB), (2) pyrochlore, (3) the hybrid HTB-pyrochlore hexagonal ordered phases, (4) body centered cubic antimonates and (5) 2K2O:3Nb2O5. Although all of these phases exhibit good ion exchange properties only the pyrochlore was prepared with Na(+) ions as an equilibrium phase and as a low porosity ceramic. Sb(+3) in the channel interferes with ionic conductivity in this case, although relatively good ionic conductivity was found for the metastable Na(+) ion exchanged analogs of RbTa2O5F and KTaWO6 pyrochlore phases.

  1. Separation of Fission Products Based on Ionic Liquids: Anion Effect

    SciTech Connect

    Luo, Huimin; Dai, Sheng; Bonnesen, Peter V.

    2004-03-28

    The applications of ionic liquids (ILs) as new separation media have been actively investigated recently. The most commonly studied class of ILs for such applications is based on dialkyl imidazolium cations. In comparison with conventional molecular solvents, ILs exhibit enhanced distribution coefficients for a number of complexing neutral ligands in extraction of metal ions from aqueous solutions. The effect of the alkyl chain length of imidazolium cations on the distribution coefficients of solvent extraction using crown ethers was the subject of a number of the previous investigations. The distribution coefficients have been found to decrease with the alkyl chain length of the IL cations. This observation implies that the extraction process also involves the exchange of the IL cations with metal ions. The longer the alkyl chain lengths of the IL cations are, the more hydrophobic the IL cations are and the more difficult to be transported into aqueous phases via ion exchange. Accordingly, the ion-exchange process is another unique property of IL-based extractions involving charged species. Here, we report the investigation about the effect of the variation of IL anions on the solvent extraction of metal ions using crown ethers as extractants. The elucidation of different solvation effects involved in ionic liquids could lead to optimized separation media for these novel solvents.

  2. Manitoba Exchange.

    ERIC Educational Resources Information Center

    Coss, Maurice

    Planning ideas and follow-up activities are described for a reciprocal exchange program between groups of 5th and 6th grade students in Manitoba who are "twinned" with another school in the province. Emphasis is on providing learning experiences which help students become familiar with the economic activity in the area, with the local government…

  3. Heat exchanger

    DOEpatents

    Wolowodiuk, Walter

    1976-01-06

    A heat exchanger of the straight tube type in which different rates of thermal expansion between the straight tubes and the supply pipes furnishing fluid to those tubes do not result in tube failures. The supply pipes each contain a section which is of helical configuration.

  4. Heat exchanger

    DOEpatents

    Daman, Ernest L.; McCallister, Robert A.

    1979-01-01

    A heat exchanger is provided having first and second fluid chambers for passing primary and secondary fluids. The chambers are spaced apart and have heat pipes extending from inside one chamber to inside the other chamber. A third chamber is provided for passing a purge fluid, and the heat pipe portion between the first and second chambers lies within the third chamber.

  5. Gelation via ion exchange in discotic suspensions.

    PubMed

    Chang, Ya-Wen; Mejia, Andres F; Cheng, Zhengdong; Di, Xiaojun; McKenna, Gregory B

    2012-06-15

    The phase behavior of charged disk suspensions displays a strong dependence on ionic strengths, as the interplay between excluded volume and electrostatic interactions determines the formation of glasses, gels, and liquid crystal states. The various ions in natural soil or brine, however, could present additional effects, especially considering that most platelet structures bear a momentous ion-exchange capacity. Here we observed how ion exchange modulates and controls the interaction between individual disks and leads to unconventional phase transitions from isotropic gel to nematic gel and finally to nematic liquid crystals.

  6. Polymeric additives for antistatic treatment of sheet molding composites (SMC)

    NASA Astrophysics Data System (ADS)

    Gedan-Smolka, Michaela; Schubert, Katrin; Taeger, Antje; Marks, Hagen

    2016-03-01

    Novel oligomeric/polymeric additives with ionic units were synthesized in a one pot procedure in order to enhance the specific surface resistivity of SMC-materials. In contrast to industrially used inorganic salts or carbon materials, such as carbon black or CNT's, these substances are nearly colorless and matrix compatible and, resulting from that, easy to homogenize with the SMC-matrix. Furthermore, it was found, that additives which can be covalently bonded to the matrix during the molding procedure are preferred compared to physically mixed substances. The effectiveness of chemically bonded substances regarding with the lowering of the specific surface resistivity is higher and selected additives do not change the reactivity and resulting mechanical properties of the molded material.

  7. Mechanically Resilient Polymeric Films Doped with a Lithium Compound

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B. (Inventor); Kinder, James D. (Inventor)

    2005-01-01

    This invention is a series of mechanically resilient polymeric films, comprising rod-coil block polyimide copolymers, which are doped with a lithium compound providing lithium ion conductivity, that are easy to fabricate into mechanically resilient films with acceptable ionic or protonic conductivity at a variety of temperatures. The copolymers consists of short-rigid polyimide rod segments alternating with polyether coil segments. The rods and coil segments can be linear, branched or mixtures of linear and branched segments. The highly incompatible rods and coil segments phase separate, providing nanoscale channels for ion conduction. The polyimide segments provide dimensional and mechanical stability and can be functionalized in a number of ways to provide specialized functions for a given application. These rod-coil black polyimide copolymers are particularly useful in the preparation of ion conductive membranes for use in the manufacture of fuel cells and lithium based polymer batteries.

  8. Nitrogen oxides under pressure: stability, ionization, polymerization, and superconductivity.

    PubMed

    Li, Dongxu; Oganov, Artem R; Dong, Xiao; Zhou, Xiang-Feng; Zhu, Qiang; Qian, Guangrui; Dong, Huafeng

    2015-11-17

    Nitrogen oxides are textbook class of molecular compounds, with extensive industrial applications. Nitrogen and oxygen are also among the most abundant elements in the universe. We explore the N-O system at 0 K and up to 500 GPa though ab initio evolutionary simulations. Results show that two phase transformations of stable molecular NO2 occur at 7 and 64 GPa, and followed by decomposition of NO2 at 91 GPa. All of the NO(+)NO3(-) structures are found to be metastable at T = 0 K, so experimentally reported ionic NO(+)NO3(-) is either metastable or stabilized by temperature. N2O5 becomes stable at 9 GPa, and transforms from P-1 to C2/c structure at 51 GPa. NO becomes thermodynamically stable at 198 GPa. This polymeric phase is superconducting (Tc = 2.0 K) and contains a -N-N- backbone.

  9. Cyanex based uranyl sensitive polymeric membrane electrodes.

    PubMed

    Badr, Ibrahim H A; Zidan, W I; Akl, Z F

    2014-01-01

    Novel uranyl selective polymeric membrane electrodes were prepared using three different low-cost and commercially available Cyanex extractants namely, bis(2,4,4-trimethylpentyl) phosphinic acid [L1], bis(2,4,4-trimethylpentyl) monothiophosphinic acid [L2] and bis(2,4,4-trimethylpentyl) dithiophosphinic acid [L3]. Optimization and performance characteristics of the developed Cyanex based polymer membrane electrodes were determined. The influence of membrane composition (e.g., amount and type of ionic sites, as well as type of plasticizer) on potentiometric responses of the prepared membrane electrodes was studied. Optimized Cyanex-based membrane electrodes exhibited Nernstian responses for UO₂(2+) ion over wide concentration ranges with fast response times. The optimized membrane electrodes based on L1, L2 and L3 exhibited Nernstian responses towards uranyl ion with slopes of 29.4, 28.0 and 29.3 mV decade(-1), respectively. The optimized membrane electrodes based on L1-L3 showed detection limits of 8.3 × 10(-5), 3.0 × 10(-5) and 3.3 × 10(-6) mol L(-1), respectively. The selectivity studies showed that the optimized membrane electrodes exhibited high selectivity towards UO₂(2+) ion over large number of other cations. Membrane electrodes based on L3 exhibited superior potentiometric response characteristics compared to those based on L1 and L2 (e.g., widest linear range and lowest detection limit). The analytical utility of uranyl membrane electrodes formulated with Cyanex extractant L3 was demonstrated by the analysis of uranyl ion in different real samples for nuclear safeguards verification purposes. The results obtained using direct potentiometry and flow-injection methods were compared with those measured using the standard UV-visible and inductively coupled plasma spectroscopic methods. PMID:24274282

  10. Cyanex based uranyl sensitive polymeric membrane electrodes.

    PubMed

    Badr, Ibrahim H A; Zidan, W I; Akl, Z F

    2014-01-01

    Novel uranyl selective polymeric membrane electrodes were prepared using three different low-cost and commercially available Cyanex extractants namely, bis(2,4,4-trimethylpentyl) phosphinic acid [L1], bis(2,4,4-trimethylpentyl) monothiophosphinic acid [L2] and bis(2,4,4-trimethylpentyl) dithiophosphinic acid [L3]. Optimization and performance characteristics of the developed Cyanex based polymer membrane electrodes were determined. The influence of membrane composition (e.g., amount and type of ionic sites, as well as type of plasticizer) on potentiometric responses of the prepared membrane electrodes was studied. Optimized Cyanex-based membrane electrodes exhibited Nernstian responses for UO₂(2+) ion over wide concentration ranges with fast response times. The optimized membrane electrodes based on L1, L2 and L3 exhibited Nernstian responses towards uranyl ion with slopes of 29.4, 28.0 and 29.3 mV decade(-1), respectively. The optimized membrane electrodes based on L1-L3 showed detection limits of 8.3 × 10(-5), 3.0 × 10(-5) and 3.3 × 10(-6) mol L(-1), respectively. The selectivity studies showed that the optimized membrane electrodes exhibited high selectivity towards UO₂(2+) ion over large number of other cations. Membrane electrodes based on L3 exhibited superior potentiometric response characteristics compared to those based on L1 and L2 (e.g., widest linear range and lowest detection limit). The analytical utility of uranyl membrane electrodes formulated with Cyanex extractant L3 was demonstrated by the analysis of uranyl ion in different real samples for nuclear safeguards verification purposes. The results obtained using direct potentiometry and flow-injection methods were compared with those measured using the standard UV-visible and inductively coupled plasma spectroscopic methods.

  11. Nanoparticle enhanced ionic liquid heat transfer fluids

    SciTech Connect

    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.

  12. Thermally Stable, Piezoelectric and Pyroelectric Polymeric Substrates

    NASA Technical Reports Server (NTRS)

    Simpson, Joycely O. (Inventor); St.Clair, Terry L. (Inventor)

    1999-01-01

    A thermally stable, piezoelectric and pyroelectric polymeric substrate was prepared. This thermally stable, piezoelectric and pyroelectric polymeric substrate may be used to prepare electromechanical transducers, thermomechanical transducers, accelerometers. acoustic sensors, infrared sensors, pressure sensors, vibration sensors, impact sensors, in-situ temperature sensors, in-situ stress/strain sensors, micro actuators, switches, adjustable fresnel lenses, speakers, tactile sensors. weather sensors, micro positioners, ultrasonic devices, power generators, tunable reflectors, microphones, and hydrophones. The process for preparing these polymeric substrates includes: providing a polymeric substrate having a softening temperature greater than 1000 C; depositing a metal electrode material onto the polymer film; attaching a plurality of electrical leads to the metal electrode coated polymeric substrate; heating the metal electrode coated polymeric substrate in a low dielectric medium; applying a voltage to the heated metal electrode coated polymeric substrate to induce polarization; and cooling the polarized metal electrode coated polymeric electrode while maintaining a constant voltage.

  13. Poly(ionic liquid) superabsorbent for polar organic solvents.

    PubMed

    Horne, W Jeffrey; Andrews, Mary A; Terrill, Kelsey L; Hayward, Spenser S; Marshall, Jeannie; Belmore, Kenneth A; Shannon, Matthew S; Bara, Jason E

    2015-05-01

    A simple, polymerized ionic liquid (poly(IL)) based on methylimidazolium cations tethered to a polystyrene backbone exhibits superabsorbent behavior toward polar organic solvents, most notably propylene carbonate (PC) and dimethyl sulfoxide (DMSO), wherein the poly(IL) was observed to swell more than 390 and 200 times (w/w) its original mass, yet absorbs negligible quantities of water, hexanes, and other solvents, many of which were miscible with the IL monomer. Although solubility parameters and dielectric constants are typically used to rationalize such behaviors, we find that poly(IL)-solvent compatibility is most clearly correlated to solvent dipole moment. Poly(IL) superabsorbency is not reliant upon the addition of a cross-linking agent. PMID:25893981

  14. Stimuli-responsive nanoparticles from ionic cellulose derivatives

    NASA Astrophysics Data System (ADS)

    Wang, Yonggui; Heinze, Thomas; Zhang, Kai

    2015-12-01

    Stimuli-responsive nanoparticles (NPs) based on sustainable polymeric feedstock still need more exploration in comparison with NPs based on synthetic polymers. In this report, stimuli-responsive NPs from novel ionic cellulose derivatives were prepared via a facile nanoprecipitation. Cellulose 10-undecenoyl ester (CUE) with a degree of substitution (DS) of 3 was synthesized by esterification of cellulose with 10-undecenoyl chloride. Then, CUE was modified by photo-induced thiol-ene reactions, in order to obtain organo-soluble ionic cellulose derivatives with DSs of ~3, namely cellulose 11-((3-carboxyl)ethylthio)undecanoate (CUE-MPA), cellulose 11-((2-aminoethyl)thio)undecanoate (CUE-CA), cellulose 11-(2-(2-(diethylamino)ethyl)thio)undecanoate (CUE-DEAET) and cellulose 11-(2-(2-(dimethylamino)ethyl)thio)undecanoate (CUE-DMAET). CUE-MPA could be transformed into NPs with average diameters in the range of 80-330 nm, but these NPs did not show particular stimuli-responsive properties. Moreover, the dropping technique resulted in smaller NPs than a dialysis technique. Stable NPs with average diameters in the range of 90-180 nm showing pH-responsive and switchable sizes were obtained from CUE-DEAET and CUE-DMAET possessing tertiary amines using nanoprecipitation. Thus, altering the terminal functional groups will be a new approach to prepare stimuli-responsive cellulose-derived polymeric NPs.Stimuli-responsive nanoparticles (NPs) based on sustainable polymeric feedstock still need more exploration in comparison with NPs based on synthetic polymers. In this report, stimuli-responsive NPs from novel ionic cellulose derivatives were prepared via a facile nanoprecipitation. Cellulose 10-undecenoyl ester (CUE) with a degree of substitution (DS) of 3 was synthesized by esterification of cellulose with 10-undecenoyl chloride. Then, CUE was modified by photo-induced thiol-ene reactions, in order to obtain organo-soluble ionic cellulose derivatives with DSs of ~3, namely cellulose

  15. Ionic polymer metal composites with polypyrrole-silver electrodes

    NASA Astrophysics Data System (ADS)

    Cellini, F.; Grillo, A.; Porfiri, M.

    2015-03-01

    Ionic polymer metal composites (IPMCs) are a class of soft active materials that are finding increasing application in robotics, environmental sensing, and energy harvesting. In this letter, we demonstrate the fabrication of IPMCs via in-situ photoinduced polymerization of polypyrrole-silver electrodes on an ionomeric membrane. The composition, morphology, and sheet resistance of the electrodes are extensively characterized through a range of experimental techniques. We experimentally investigate IPMC electrochemistry through electrochemical impedance spectroscopy, and we propose a modified Randle's model to interpret the impedance spectrum. Finally, we demonstrate in-air dynamic actuation and sensing and assess IPMC performance against more established fabrication methods. Given the simplicity of the process and the short time required for the formation of the electrodes, we envision the application of our technique in the development of a rapid prototyping technology for IPMCs.

  16. The hype with ionic liquids as solvents

    NASA Astrophysics Data System (ADS)

    Kunz, Werner; Häckl, Katharina

    2016-09-01

    In this mini review, we give our personal opinion about the present state of the art concerning Ionic Liquids, proposed as alternative solvents. In particular, we consider their different drawbacks and disadvantages and discuss the critical aspects of the research of Ionic Liquids as solvents. Finally, we point out some aspects on potentially promising Ionic Liquid solvents.

  17. Novel polymeric materials from triglycerides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Triglycerides are good platforms for new polymeric products that can substitute for petroleum-based materials. As part of our research emphasis in sustainability and green polymer chemistry, we have explored a number of reactions in efforts to produce a wide range of value-added products. In this ...

  18. Supramolecular polymerization: Living it up

    NASA Astrophysics Data System (ADS)

    Würthner, Frank

    2014-03-01

    Protein fibril formation is involved in many human diseases and thus has been mechanistically elucidated in the context of understanding -- and in turn treating -- them. This biological phenomenon has now also inspired the design of a supramolecular system that undergoes living polymerization.

  19. The absorption of polymeric composites

    NASA Astrophysics Data System (ADS)

    Řídký, R.; Popovič, M.; Rolc, S.; Drdlová, M.; Krátký, J.

    2016-06-01

    An absorption capacity of soft, viscoelastic materials at high strain rates is important for wide range of practical applications. Nowadays there are many variants of numerical models suitable for this kind of analysis. The main difficulty is in selection of the most realistic numerical model and a correct setup of many unknown material constants. Cooperation between theoretical simulations and real testing is next crucial point in the investigation process. Standard open source material database offer material properties valid for strain rates less than 250 s-1. There are experiments suitable for analysis of material properties with strain rates close to 2000 s-1. The high strain-rate characteristics of a specific porous blast energy absorbing material measured by modified Split Hopkinson Pressure Bar apparatus is presented in this study. Testing these low impedance materials using a metallic split Hopkinson pressure bar setup results in poor signal to noise ratios due to impedance mismatching. These difficulties are overcome by using polymeric Hopkinson bars. Conventional Hopkinson bar analysis cannot be used on the polymeric bars due to the viscoelastic nature of the bar material. One of the possible solution leads to complex and frequency depended Young modulus of testing bars material. This testing technique was applied to materials composed of porous glass/ceramic filler and polymeric binder, with density of 125 - 300 kg/m3 and particle size in range of 50 µm - 2 mm. The achieved material model was verified in practical application of sandwich structure includes polymeric composites under a blast test.

  20. The Viscosity of Polymeric Fluids.

    ERIC Educational Resources Information Center

    Perrin, J. E.; Martin, G. C.

    1983-01-01

    To illustrate the behavior of polymeric fluids and in what respects they differ from Newtonian liquids, an experiment was developed to account for the shear-rate dependence of non-Newtonian fluids. Background information, procedures, and results are provided for the experiment. Useful in transport processes, fluid mechanics, or physical chemistry…

  1. Buckling of polymerized monomolecular films

    NASA Astrophysics Data System (ADS)

    Bourdieu, L.; Daillant, J.; Chatenay, D.; Braslau, A.; Colson, D.

    1994-03-01

    The buckling of a two-dimensional polymer network at the air-water interface has been evidenced by grazing incidence x-ray scattering. A comprehensive description of the inhomogeneous octadecyltrichlorosilane polymerized film was obtained by atomic force microscopy and x-ray scattering measurements. The buckling occurs with a characteristic wavelength ~=10 μm.

  2. Cesium-specific phenolic ion exchange resin

    DOEpatents

    Bibler, J.P.; Wallace, R.M.

    1995-08-15

    A phenolic, cesium-specific, cation exchange resin is prepared by neutralizing resorcinol with potassium hydroxide, condensing/polymerizing the resulting intermediate with formaldehyde, heat-curing the resulting polymer to effect cross-linking and grinding it to desired particle size for use. This resin will selectively and efficiently adsorb cesium ions in the presence of a high concentration of sodium ions with a low carbon to cesium ratio. 2 figs.

  3. Cesium-specific phenolic ion exchange resin

    DOEpatents

    Bibler, Jane P.; Wallace, Richard M.

    1995-01-01

    A phenolic, cesium-specific, cation exchange resin is prepared by neutralizing resorcinol with potassium hydroxide, condensing/polymerizing the resulting intermediate with formaldehyde, heat-curing the resulting polymer to effect cross-linking and grinding it to desired particle size for use. This resin will selectively and efficiently adsorb cesium ions in the presence of a high concentration of sodium ions with a low carbon to cesium ratio.

  4. Nonlinear optical and conductive polymeric material

    DOEpatents

    Barton, Thomas J.; Ijadi-Maghsoodi, Sina; Pang, Yi

    1992-05-19

    A polymeric material which exhibits nonlinear optical properties if undoped and conductive properties if doped. The polymer is prepared by polymerizing diethynylsilane compositions, the resulting polymeric material having a weight average molecular weight between about 20,000 and about 200,000 grams per mole. The polymer is prepared and catalytically polymerized by exposure to a catalyst, such as MoCl.sub.5 or W(CO).sub.6 /hv.

  5. Nonlinear optical and conductive polymeric material

    DOEpatents

    Barton, Thomas J.; Ijadi-Maghsoodi, Sina; Pang, Yi

    1993-10-19

    A polymeric material which exhibits nonlinear optical properties if undoped and conductive properties if doped. The polymer is prepared by polymerizing diethynylsilane compositions, the resulting polymeric material having a weight average molecular weight between about 20,000 and about 200,000 grams per mole. The polymer is prepared and catalytically polymerized by exposure to a catalyst, such as MoCl.sub.5 or W(CO).sub.6 /hv.

  6. Nonlinear optical and conductive polymeric material

    DOEpatents

    Barton, T.J.; Ijadi-Maghsooodi, S; Yi Pang.

    1993-10-19

    A polymeric material is described which exhibits nonlinear optical properties if undoped and conductive properties if doped. The polymer is prepared by polymerizing diethynylsilane compositions, the resulting polymeric material having a weight average molecular weight between about 20,000 and about 200,000 grams per mole. The polymer is prepared and catalytically polymerized by exposure to a catalyst, such as MoCl[sub 5] or W(CO)[sub 6].

  7. Nonlinear optical and conductive polymeric material

    DOEpatents

    Barton, T.J.; Ijadi-Maghsoodi, S.; Pang, Y.

    1992-05-19

    A polymeric material which exhibits nonlinear optical properties if undoped and conductive properties if doped. The polymer is prepared by polymerizing diethynylsilane compositions, the resulting polymeric material having a weight average molecular weight between about 20,000 and about 200,000 grams per mole. The polymer is prepared and catalytically polymerized by exposure to a catalyst, such as MoCl[sub 5] or W(CO)[sub 6]/hv.

  8. All-Inorganic Germanium Nanocrystal Films by Cationic Ligand Exchange.

    PubMed

    Wheeler, Lance M; Nichols, Asa W; Chernomordik, Boris D; Anderson, Nicholas C; Beard, Matthew C; Neale, Nathan R

    2016-03-01

    We introduce a new paradigm for group IV nanocrystal surface chemistry based on room temperature surface activation that enables ionic ligand exchange. Germanium nanocrystals synthesized in a gas-phase plasma reactor are functionalized with labile, cationic alkylammonium ligands rather than with traditional covalently bound groups. We employ Fourier transform infrared and (1)H nuclear magnetic resonance spectroscopies to demonstrate the alkylammonium ligands are freely exchanged on the germanium nanocrystal surface with a variety of cationic ligands, including short inorganic ligands such as ammonium and alkali metal cations. This ionic ligand exchange chemistry is used to demonstrate enhanced transport in germanium nanocrystal films following ligand exchange as well as the first photovoltaic device based on an all-inorganic germanium nanocrystal absorber layer cast from solution. This new ligand chemistry should accelerate progress in utilizing germanium and other group IV nanocrystals for optoelectronic applications.

  9. All-inorganic Germanium nanocrystal films by cationic ligand exchange

    DOE PAGES

    Wheeler, Lance M.; Nichols, Asa W.; Chernomordik, Boris D.; Anderson, Nicholas C.; Beard, Matthew C.; Neale, Nathan R.

    2016-01-21

    In this study, we introduce a new paradigm for group IV nanocrystal surface chemistry based on room temperature surface activation that enables ionic ligand exchange. Germanium nanocrystals synthesized in a gas-phase plasma reactor are functionalized with labile, cationic alkylammonium ligands rather than with traditional covalently bound groups. We employ Fourier transform infrared and 1H nuclear magnetic resonance spectroscopies to demonstrate the alkylammonium ligands are freely exchanged on the germanium nanocrystal surface with a variety of cationic ligands, including short inorganic ligands such as ammonium and alkali metal cations. This ionic ligand exchange chemistry is used to demonstrate enhanced transport inmore » germanium nanocrystal films following ligand exchange as well as the first photovoltaic device based on an all-inorganic germanium nanocrystal absorber layer cast from solution. This new ligand chemistry should accelerate progress in utilizing germanium and other group IV nanocrystals for optoelectronic applications.« less

  10. Fabrication and Characterization of Polysaccharide Ion Gels with Ionic Liquids and Their Further Conversion into Value-Added Sustainable Materials

    PubMed Central

    Takada, Akihiko; Kadokawa, Jun-ichi

    2015-01-01

    A review of the fabrication of polysaccharide ion gels with ionic liquids is presented. From various polysaccharides, the corresponding ion gels were fabricated through the dissolution with ionic liquids. As ionic liquids, in the most cases, 1-butyl-3-methylimidazolium chloride has been used, whereas 1-allyl-3methylimidazolium acetate was specifically used for chitin. The resulting ion gels have been characterized by suitable analytical measurements. Characterization of a pregel state by viscoelastic measurement provided the molecular weight information. Furthermore, the polysaccharide ion gels have been converted into value-added sustainable materials by appropriate procedures, such as exchange with other disperse media and regeneration. PMID:25793912

  11. Glycine Polymerization on Oxide Minerals

    NASA Astrophysics Data System (ADS)

    Kitadai, Norio; Oonishi, Hiroyuki; Umemoto, Koichiro; Usui, Tomohiro; Fukushi, Keisuke; Nakashima, Satoru

    2016-07-01

    It has long been suggested that mineral surfaces played an important role in peptide bond formation on the primitive Earth. However, it remains unclear which mineral species was key to the prebiotic processes. This is because great discrepancies exist among the reported catalytic efficiencies of minerals for amino acid polymerizations, owing to mutually different experimental conditions. This study examined polymerization of glycine (Gly) on nine oxide minerals (amorphous silica, quartz, α-alumina and γ-alumina, anatase, rutile, hematite, magnetite, and forsterite) using identical preparation, heating, and analytical procedures. Results showed that a rutile surface is the most effective site for Gly polymerization in terms of both amounts and lengths of Gly polymers synthesized. The catalytic efficiency decreased as rutile > anatase > γ-alumina > forsterite > α- alumina > magnetite > hematite > quartz > amorphous silica. Based on reported molecular-level information for adsorption of Gly on these minerals, polymerization activation was inferred to have arisen from deprotonation of the NH3 + group of adsorbed Gly to the nucleophilic NH2 group, and from withdrawal of electron density from the carboxyl carbon to the surface metal ions. The orientation of adsorbed Gly on minerals is also a factor influencing the Gly reactivity. The examination of Gly-mineral interactions under identical experimental conditions has enabled the direct comparison of various minerals' catalytic efficiencies and has made discussion of polymerization mechanisms and their relative influences possible Further systematic investigations using the approach reported herein (which are expected to be fruitful) combined with future microscopic surface analyses will elucidate the role of minerals in the process of abiotic peptide bond formation.

  12. Polymer-based separations: Synthesis and application of polymers for ionic and molecular recognition. Annual performance report, August 1, 1993--July 31, 1994

    SciTech Connect

    Alexandratos, S.D.

    1994-04-01

    During this period, focus was on design and synthesis of bifunctional polymers for complexing metal ions from aqueous solutions; this could provide a means for separating radioactive and toxic metal ions from contaminated waste water as well as valuable metals from dilute ore processing streams. The synthesis of bifunctional polymers required a new preparative technique; bifunctional interpenetrating polymer networks (IPN) was an important part of the studies. In the preparation, a pre-formed crosslinked polymer is contacted with a solution of monomers, and a second network was polymerized within the first. Imidazole ligands were used. A new resin, prepared with a macrocyclic sorbed within polystyrene beads modified with sulfonic acid ligands, extracted Cu(II) 10--100-fold. Maximum metal ion complexation rates depend on a balance between chemical interactions and physical parameters (matrix porosity, rigidity). A novel ion exchange resin (Diphonix{trademark}) has been produced which displays both ionic selectivity (diphosphonic acid ligands) and rapid complexation rates (sulfonic acid ligands).

  13. Electrical control of the exchange spring in antiferromagnetic metals.

    PubMed

    Wang, Yuyan; Zhou, Xiang; Song, Cheng; Yan, Yinuo; Zhou, Shiming; Wang, Guangyue; Chen, Chao; Zeng, Fei; Pan, Feng

    2015-05-27

    Electrical control of the exchange spring in antiferromagnetic metals is obtained in [Co/Pt]/IrMn Hall devices by using an ionic liquid, where the exchange spring could transfer the "force" and enable a deeper modulation depth in the IrMn. This work provides a new approach toward electrical modulation of the spin structures in metallic antiferromagnets, which should be significant in advancing the development of low-power-consumption antiferromagnet (AFM) spintronics.

  14. Hydrolytic polymerization of chromium (III). 2. A trimeric species

    SciTech Connect

    Finholt, J.E.; Thompson, M.E.; Connick, R.E.

    1981-12-01

    With use of an ion-exchange displacement elution, a green species was separated from mixtures of Cr(III) polymers and its absorption spectrum determined. The hydroxides per chromium atom were found to be 4/3, and the charge per chromium atom was shown to be consistent with this value. The degree of polymerization of freezing point depression was close to 3. Measurements are reported for the equilibrium quotient for the formation of the trimer from the monomer. The ESR spectrum and magnetic susceptibility were determined, and the results are discussed in terms of possible structures.

  15. Observation of ionic Coulomb blockade in nanopores

    NASA Astrophysics Data System (ADS)

    Feng, Jiandong; Liu, Ke; Graf, Michael; Dumcenco, Dumitru; Kis, Andras; di Ventra, Massimiliano; Radenovic, Aleksandra

    2016-08-01

    Emergent behaviour from electron-transport properties is routinely observed in systems with dimensions approaching the nanoscale. However, analogous mesoscopic behaviour resulting from ionic transport has so far not been observed, most probably because of bottlenecks in the controlled fabrication of subnanometre nanopores for use in nanofluidics. Here, we report measurements of ionic transport through a single subnanometre pore junction, and the observation of ionic Coulomb blockade: the ionic counterpart of the electronic Coulomb blockade observed for quantum dots. Our findings demonstrate that nanoscopic, atomically thin pores allow for the exploration of phenomena in ionic transport, and suggest that nanopores may also further our understanding of transport through biological ion channels.

  16. Application of Ionic Liquids in Hydrometallurgy

    PubMed Central

    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

  17. Study of surface-bonded dicationic ionic liquids as stationary phases for hydrophilic interaction chromatography.

    PubMed

    Qiao, Lizhen; Li, Hua; Shan, Yuanhong; Wang, Shuangyuan; Shi, Xianzhe; Lu, Xin; Xu, Guowang

    2014-02-21

    In the present study, several geminal dicationic ionic liquids based on 1,4-bis(3-allylimidazolium)butane and 1,8-bis(3-allylimidazolium)octane in combination with different anions bromide and bis(trifluoromethanesulphonyl)imide were prepared and then bonded to the surface of 3-mercaptopropyl modified silica materials through the "thiol-ene" click chemistry as stationary phases for hydrophilic interaction chromatography (HILIC). Compared with their monocationic analogues, the dicationic ionic liquids stationary phases presented effective retention and good selectivity for typical hydrophilic compounds under HILIC mode with the column efficiency as high as 130,000 plates/m. Moreover, the influence of different alkyl chain spacer between dications and combined anions on the retention behavior and selectivity of the dicationic ionic liquids stationary phases under HILIC mode was displayed. The results indicated that the longer linkage chain would decrease the hydrophilicity and retention on the dicationic ionic liquid stationary phase, and while differently combined anions had no difference due to the exchangeability under the common HILIC mobile phase with buffer salt. Finally, the retention mechanism was investigated by evaluating the effect of chromatographic factors on retention, including the water content in the mobile phase, the mobile phase pH and buffer salt concentration. The results showed that the dicationic ionic liquids stationary phases presented a mixed-mode retention behavior with HILIC mechanism and anion exchange.

  18. Nanoparticles in ionic liquids: interactions and organization.

    PubMed

    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.

  19. [Ion specificity during ion exchange equilibrium in natural clinoptilolite].

    PubMed

    He, Yun-Hua; Li, Hang; Liu, Xin-Min; Xiong, Hai-Ling

    2015-03-01

    Zeolites have been widely applied in soil improvement and environment protection. The study on ion specificity during ion exchange equilibrium is of important significance for better use of zeolites. The maximum adsorption capacities of alkali ions during ion exchange equilibrium in the clinoptilolite showed obvious specificity. For alkali metal ions with equivalent valence, the differences in adsorption capacity increased with the decrease of ionic concentration. These results cannot be well explained by the classical theories including coulomb force, ionic size, hydration, dispersion force, classic induction force and surface complexation. We found that the coupling of polarization effects resulted from the quantum fluctuation of diverse alkali metal ions and electric field near the zeolite surface should be the primary reason for specific ion effect during ion exchange in zeolite. The result of this coupling effect was that the difference in the ion dipole moment increased with the increase of surface potential, which further expanded the difference in the adsorption ability between zeolite surface and ions, resulting in different ion exchange adsorption ability at the solid/liquid interface. Due to the high surface charge density of zeolite, ionic size also played an important role in the distribution of ions in the double diffuse layer, which led to an interesting result that distinct differences in exchange adsorption ability of various alkali metal ions were only detected at high surface potential (the absolute value was greater than 0.2 V), which was different from the ion exchange equilibrium result on the surface with low charge density.

  20. Effect of dipolar ions on the entropy-driven polymerization of tobacco mosaic virus protein.

    PubMed

    Lauffer, M A; Shalaby, R A

    1985-11-01

    The effect of the dipolar ions, glycine, glycylglycine, and glycylglycylglycine on the polymerization of tobacco mosaic virus (TMV) protein has been studied by the methods of light scattering and ultracentrifugation. All three dipolar ions promote polymerization. The major reaction in the early stage is transition from the 4 S to the 20 S state. As in the absence of dipolar ions, the polymerization is enhanced by an increase in temperature; it is endothermic and therefore entropy-driven. The effect of the dipolar ions can be understood in terms of their action as salting-out agents; they increase the activity coefficient of TMV A protein, the 4 S material, and thus shift the equilibrium toward the 20 S state. The salting-out constants, K, for the reaction in 0.10 ionic strength phosphate buffer at pH 6.7 was found by the light scattering method to be 1.6 for glycine, 2.5 for glycylglycine, and 2.5 for glycylglycylglycine. A value of 2.7 was obtained by the ultracentrifugation method for glycylglycine in phosphate buffer at 0.1 ionic strength and pH 6.8 at 10 degrees C. For both glycine and glycylglycine, K increases when the ionic strength of the phosphate buffer is decreased. This result suggests that electrolytes decrease the activity coefficient of the dipolar ions, a salting-in phenomenon. However, the salting-in constants evaluated from these results are substantially higher than those previously determined by solubility measurements. The effect of glycine and glycylglycine on polymerization was studied at pH values between 6.2 and 6.8. The effectiveness of both dipolar ions is approximately 50% greater at pH 6.8 than at pH 6.2. The variation of the extent of polymerization with pH in the presence of the dipolar ions is consistent with the interpretation that approximately one hydrogen ion is bound for half of the polypeptide units in the polymerized A protein.

  1. Multiscale implications of stress-induced ionic polymer transducer sensing

    NASA Astrophysics Data System (ADS)

    Zangrilli, Ursula Therese

    Ionic Polymer Transducers (IPTs) can act as both actuators and sensors. As actuators, the energy density values are much better than PZT or PVDF materials. As sensors, IPTs are extraordinarily sensitive and have the potential to be used in any mode of deformation. However, application of IPT sensors is limited because of a lack of understanding of their fundamental physics. In this work, the main focus will be to explore and develop a better understanding of how IPTs function with respect to shear deformation. In turn, the results developed here will improve upon the state of understanding of IPT sensors in general and potentially expand meaningful application opportunities. Because IPT active response is a multiscale phenomenon, this study adopts a multiscale modeling framework. Of interest are the interplay among the polymeric backbone of the ionic polymer, the diluent present in the hydrophilic regions of the polymer and the interspersed electrode particulate. To begin, this work improves upon a past multiscale modeling framework for the polymer backbone based upon Rotational Isomeric State Theory such that the effects of material anisotropy may be considered. This is potentially significant in light of the polymer manufacturing process. These modeling results are then incorporated into a model of the diluent movement within the ionic transport regions of the IPT. The electrical current predictions are based upon streaming potential theories. Finally, this model incorporates viscoelastic behavior in order to develop a better understanding of the coupling of these two systems (the polymer and the diluent) and how this coupling influence affects the expected current output over time.

  2. Preparation of Poly(ionic liquid)s-Supported Recyclable Organocatalysts for the Asymmetric Nitroaldol (Henry) Reaction.

    PubMed

    Großeheilmann, Julia; Bandomir, Jenny; Kragl, Udo

    2015-12-21

    A novel strategy for the embedding of quinine-based organocatalysts in polymerized ionic liquids-based hydrogels is presented. With this technique, the encapsulated organocatalyst was successfully recovered and reused for four cycles without any loss of enantioselectivity (up to 91% ee) for the asymmetric nitroaldol (Henry) reaction. In this study, high catalyst leaching was significantly reduced (<0.01%) by controlling the water content. After catalyst removal, evaporation of the solvent affords the product in 98% purity without any further purification.

  3. Performances and mechanistic investigations of a triphosphine trioxide/ionic liquid system for rare earth extraction.

    PubMed

    Turgis, R; Arrachart, G; Dubois, V; Dourdain, S; Virieux, D; Michel, S; Legeai, S; Lejeune, M; Draye, M; Pellet-Rostaing, S

    2016-01-21

    The extraction of rare earth elements (REEs) from nitric acid solution with a triphosphine trioxide (TPO) is presented. Performances of such a ligand in ionic liquids vs. a classical solvent (benzyl ether) are compared. TPO seems to be 10 to 100 times more efficient when it is dissolved in ionic media whatever the concentration of nitric acid involved. Mechanistic investigations reveal that cation exchange classically observed in ionic liquids is not consistent with the experimental data. Moreover, clear differences in the TPO/Ln complexes between classical and ionic media are highlighted. A stable complex of 1 lanthanide for 3 TPO is formed in an ionic liquid whereas a complex of 1 lanthanide for 6 to 9 TPO is formed in benzyl ether. Back extraction is also studied and good recovery of REEs could be obtained. The TPO/ionic liquid system shows remarkable performances i.e. efficiency and selectivity towards lanthanides in a simulated leaching solution of a Nd/Fe/B/Dy magnet.

  4. Morphology and transport in ionic membranes

    NASA Astrophysics Data System (ADS)

    Disabb-Miller, Melanie Lisa

    Ion-containing polymers for fuel cell membranes have been studied to determine the chemical structure and ion content relationship to membrane water uptake, conductivity, and morphology. Random and block copolymer proton exchange membranes (PEMs) and anion exchange membranes (AEMs) with unique properties, such as diblock and triblock copolymers, superacidic moieties, and charge-delocalized polymer-tethered Ru-complex based cations, were investigated, and new metrics were developed to analyze fundamental ion transport behavior in these polymers. The morphology of the polymer systems was examined using small angle x-ray scattering (SAXS), small angle neutron scattering (SANS), and transmission electron microscopy (TEM). By studying a number of different ion-conducting systems using multiple techniques and deep analysis of structure-property relationships, a more complete picture of the property landscape of these materials was developed. Model diblock and unique triblock copolymer systems with center-functionalized blocks based on poly(styrene), PS, and poly(hexyl methacrylate), PHMA, were synthesized via atom transfer radical polymerization (ATRP). The PS block was functionalized for backbone-independent comparisons of PEM and AEM water uptake and conductivity to provide insight in how the properties of PEMs and AEMs compare and aid in further AEM development. The ratio of the mobile ion diffusion coefficients and dilute solution ion diffusivity (D/D0) was developed as a new metric, allowing for accurate comparison of polymer systems with different ion moieties and contents. Subsequently, it was determined that block copolymer PEMs and AEMs demonstrate the same barriers to ion transport if the mobility of the charge carrier is considered.

  5. Polymeric cationic substituted acrylamide surfactants

    SciTech Connect

    Nieh, E.C.Y.

    1983-11-15

    A new composition of matter comprises a copolymer of a surface active quaternary ammonium monomer salt and from 50 to 97% by wt of acrylamide. The new copolymers can have molecular weights substantially greater than 10,000 and still remain water soluble and surface active. Copolymers are prepared by polymerization techniques known in the art. The quaternary ammonium monomer is dispersed under inert atmosphere in aqueous solution which may additionally contain dissolved therein a low molecular weight alcohol such as ethanol, isopropanol, and the like. Acidic polymerization initiator such as the azo initiators, organic peroxides, or redox initiators such as the sulfite- persulfate system is then added in an amount calculated to yield a polymer product of desired molecular weight. (14 claims.

  6. Metal containing polymeric functional microspheres

    NASA Technical Reports Server (NTRS)

    Yen, Shiao-Ping S. (Inventor); Rembaum, Alan (Inventor); Molday, Robert S. (Inventor)

    1979-01-01

    Polymeric functional microspheres containing metal or metal compounds are formed by addition polymerization of a covalently bondable olefinic monomer such as hydroxyethylmethacrylate in the presence of finely divided metal or metal oxide particles, such as iron, gold, platinum or magnetite, which are embedded in the resulting microspheres. The microspheres can be covalently bonded to chemotherapeutic agents, antibodies, or other proteins providing a means for labeling or separating labeled cells. Labeled cells or microspheres can be concentrated at a specific body location such as in the vicinity of a malignant tumor by applying a magnetic field to the location and then introducing the magnetically attractable microspheres or cells into the circulatory system of the subject. Labeled cells can be separated from a cell mixture by applying a predetermined magnetic field to a tube in which the mixture is flowing. After collection of the labeled cells, the magnetic field is discontinued and the labeled sub-cell population recovered.

  7. Quantized ionic conductance in nanopores

    SciTech Connect

    Zwolak, Michael; Lagerqvist, Johan; Di Ventra, Massimilliano

    2009-01-01

    Ionic transport in nanopores is a fundamentally and technologically important problem in view of its ubiquitous occurrence in biological processes and its impact on DNA sequencing applications. Using microscopic calculations, we show that ion transport may exhibit strong non-liDearities as a function of the pore radius reminiscent of the conductance quantization steps as a function of the transverse cross section of quantum point contacts. In the present case, however, conductance steps originate from the break up of the hydration layers that form around ions in aqueous solution. Once in the pore, the water molecules form wavelike structures due to multiple scattering at the surface of the pore walls and interference with the radial waves around the ion. We discuss these effects as well as the conditions under which the step-like features in the ionic conductance should be experimentally observable.

  8. Radiation-hardened polymeric films

    DOEpatents

    Arnold, C. Jr.; Hughes, R.C.; Kepler, R.G.; Kurtz, S.R.

    1984-07-16

    The radiation-induced conductivity of polymeric dielectrics with low electronic mobility is reduced by doping with electron donor or electron acceptor compounds at a level of 10/sup 15/ to 10/sup 21/ molecules of dopant/cm/sup 3/. Polyesters, polyolefins, perfluoropolyolefins, vinyl polymers, vinylidene polymers, polycarbonates, polysulfones and polyimides can benefit from such a treatment. Usable dopants include 2,4,7-trinitro-9-fluorenone, tetracyanethylene, 7,7,8,8-tetracyanoquinodimethane, m-dinitrobenzene, 2-isopropylcarbazole, and triphenylamine.

  9. Radiation-hardened polymeric films

    DOEpatents

    Arnold, Jr., Charles; Hughes, Robert C.; Kepler, R. Glen; Kurtz, Steven R.

    1986-01-01

    The radiation-induced conductivity of polymeric dielectrics with low electronic mobility is reduced by doping with electron donor or electron acceptor compounds at a level of 10.sup.15 to 10.sup.21 molecules of dopant/cm.sup.3. Polyesters, polyolefins, perfluoropolyolefins, vinyl polymers, vinylidene polymers, polycarbonates, polysulfones and polyimides can benefit from such a treatment. Usable dopants include 2,4,7-trinitro-9-fluorenone, tetracyanethylene, 7,7,8,8-tetracyanoquinodimethane, m-dinitrobenzene, 2-isopropylcarbazole, and triphenylamine.

  10. Ionic contamination detection. Final report

    SciTech Connect

    Benkovich, M.G.

    1994-04-01

    The effectiveness of Meter A and B for detecting ionic contamination was evaluated and compared on the following types of samples: (1) copper panels, (2) printed wiring boards with through-hold components (lCs), (3) printed wiring boards with surface-mounted components, and (4) mixed-technology printed wiring boards (both through-hole and surface-mount components). The extraction efficiency of the two meters was calculated

  11. Phase Behavior of Ionic Microgels

    NASA Astrophysics Data System (ADS)

    Gottwald, D.; Likos, C. N.; Kahl, G.; Löwen, H.

    2004-02-01

    We employ effective interaction potentials between spherical polyelectrolyte microgels in order to investigate theoretically the structure, thermodynamics, and phase behavior of ionic microgel solutions. Combining a genetic algorithm with accurate free energy calculations we are able to perform an unrestricted search of candidate crystal structures. Hexagonal, body-centered orthogonal, and trigonal crystals are found to be stable at high concentrations and charges of the microgels, accompanied by reentrant melting behavior and fluid-fcc-bcc transitions below the overlap concentration.

  12. Two Photon Polymerization of Ormosils

    NASA Astrophysics Data System (ADS)

    Matei, A.; Zamfirescu, M.; Jipa, F.; Luculescu, C.; Dinescu, M.; Buruiana, E. C.; Buruiana, T.; Sima, L. E.; Petrescu, S. M.

    2010-10-01

    In this work, 3D structures of hybrid polymers—ORMOSILS (organically modified silicates) were produced via Two Photon Polymerization (2PP) of hybrid methacrylates based on silane derivates. Synthetic routes have been used to obtain series of hybrid monomers, their structure and purity being checked by NMR Spectroscopy and Fourier Transform Infrared Spectroscopy. Two photon polymerization method (a relatively new technology which allows fast micro and nano processing of three-dimensional structures with application in medical devices, tissue scaffolds, photonic crystals etc) was used for monomers processing. As laser a Ti: Sapphire laser was used, with 200 fs pulse duration and 2 kHz repetition rate, emitting at 775 nm. A parametric study on the influence of the processing parameters (laser fluence, laser scanning velocity, photo initiator) on the written structures was carried out. The as prepared polymeric scaffolds were tested in mesenchymal stem cells and fibroblasts cell cultures, with the aim of further obtaining bone and dermal grafts. Cells morphology, proliferation, adhesion and alignment were analyzed for different experimental conditions.

  13. Composite plasma polymerized sulfonated polystyrene membrane for PEMFC

    SciTech Connect

    Nath, Bhabesh Kumar; Khan, Aziz; Chutia, Joyanti

    2015-10-15

    Highlights: • Methyl methane sulfonate (MMS) is used as the sulfonating agent. • The proton conductivity of the membrane is found to be 0.141 S cm{sup −1}. • Power density of fuel cell with styrene/MMS membrane is 0.5 W cm{sup −2}. • The membrane exhibits thermal stability up to 140 °C. - Abstract: This work presents the introduction of an organic compound methyl methane sulfonate (MMS) for the first time in fabrication of polystyrene based proton exchange membrane (PEM) by plasma polymerization process. The membrane is fabricated by co-polymerizing styrene and MMS in capacitively coupled continuous RF plasma. The chemical composition of the plasma polymerized polymer membrane is investigated using Fourier Transform Infrared Spectroscopy which reveals the formation of composite structure of styrene and MMS. The surface morphology studied using AFM and SEM depicts the effect of higher partial pressure of MMS on surface topography of the membrane. The proton transport property of the membrane studied using electrochemical impedance spectroscopy shows the achievement of maximum proton conductivity of 0.141 S cm{sup −1} which is comparable to Nafion 117 membrane. Fuel cell performance test of the synthesized membrane shows a maximum power density of 500 mW cm{sup −2} and current density of 0.62 A cm{sup −2} at 0.6 V.

  14. Ionic Liquids to Replace Hydrazine

    NASA Technical Reports Server (NTRS)

    Koelfgen, Syri; Sims, Joe; Forton, Melissa; Allan, Barry; Rogers, Robin; Shamshina, Julia

    2011-01-01

    A method for developing safe, easy-to-handle propellants has been developed based upon ionic liquids (ILs) or their eutectic mixtures. An IL is a binary combination of a typically organic cation and anion, which generally produces an ionic salt with a melting point below 100 deg C. Many ILs have melting points near, or even below, room temperature (room temperature ionic liquids, RTILs). More importantly, a number of ILs have a positive enthalpy of formation. This means the thermal energy released during decomposition reactions makes energetic ILs ideal for use as propellants. In this specific work, to date, a baseline set of energetic ILs has been identified, synthesized, and characterized. Many of the ILs in this set have excellent performance potential in their own right. In all, ten ILs were characterized for their enthalpy of formation, density, melting point, glass transition point (if applicable), and decomposition temperature. Enthalpy of formation was measured using a microcalorimeter designed specifically to test milligram amounts of energetic materials. Of the ten ILs characterized, five offer higher Isp performance than hydrazine, ranging between 10 and 113 seconds higher than the state-of-the-art propellant. To achieve this level of performance, the energetic cations 4- amino-l,2,4-triazolium and 3-amino-1,2,4-triazolium were paired with various anions in the nitrate, dicyanamide, chloride, and 3-nitro-l,2,4-triazole families. Protonation, alkylation, and butylation synthesis routes were used for creation of the different salts.

  15. Purification of brain tubulin through two cycles of polymerization-depolymerization in a high-molarity buffer.

    PubMed

    Castoldi, Mirco; Popov, Andrei V

    2003-11-01

    Microtubules can be assembled in vitro from purified alpha/beta tubulin heterodimers in the presence of GTP. Tubulin is routinely obtained from animal brain tissue through repetitive cycles of polymerization-depolymerization, followed by ion-exchange chromatography to remove any contaminating microtubule-associated proteins and motors. Here, we show that only two cycles of polymerization-depolymerization of pig brain tubulin in the presence of a high-molarity PIPES buffer allow the efficient removal of contaminating proteins and production of a high-concentration tubulin solution. The proposed protocol is rapid and yields more active tubulin than the traditional ion-exchange chromatography-based procedures.

  16. Heat-Exchange Fluids for Sulfuric Acid Vaporizers

    NASA Technical Reports Server (NTRS)

    Lawson, D. D.; Petersen, G. R.

    1982-01-01

    Some fluorine-substituted organic materials meet criteria for heat-exchange fluids in contact with sulfuric acid. Most promising of these are perfluoropropylene oxide polymers with degree of polymerization (DP) between 10 and 50. It is desirable to have DP in high range because vapor pressure of material decreases as DP increases, and high-DP liquids have lower loss due to vaporization.

  17. Reversible deactivation radical polymerization mediated by cobalt complexes: recent progress and perspectives.

    PubMed

    Peng, Chi-How; Yang, Tsung-Yao; Zhao, Yaguang; Fu, Xuefeng

    2014-11-21

    Mediation of reversible deactivation radical polymerization (RDRP) by cobalt(II) complexes (CMRP) is the most highly developed subcategory of organometallic mediated RDRP (OMRP). Attention was paid to CMRP for its unusual high efficiency observed for the control of acrylate and vinyl acetate polymerization that produced homo- and block copolymers with narrow molecular weight distribution and a predictable molecular weight. The reactions of organic radicals with cobalt(II) metallo-radicals and organo-cobalt(III) complexes have a central role in the pathways that mediate this type of reversible deactivation radical polymerization. The reversible deactivation pathway dominates the polymerization when cobalt(II) complexes can reversibly deactivate the radicals to form organo-cobalt(III) complexes. Degenerative transfer becomes the major pathway when the cobalt(II) species fully convert to organo-cobalt(III) complexes and the radicals in solution rapidly exchange with radicals in organo-cobalt(III) complexes. This review describes the polymerization behavior and control mechanisms used by cobalt complexes in the mediation of reversible deactivation radical polymerization. The emerging developments for CMRP in the aqueous phase and with photo-initiation are also described, followed by the challenges and future applications of this method.

  18. Ultrasound-Mediated Polymeric Micelle Drug Delivery.

    PubMed

    Xia, Hesheng; Zhao, Yue; Tong, Rui

    2016-01-01

    The synthesis of multi-functional nanocarriers and the design of new stimuli-responsive means are equally important for drug delivery. Ultrasound can be used as a remote, non-invasive and controllable trigger for the stimuli-responsive release of nanocarriers. Polymeric micelles are one kind of potential drug nanocarrier. By combining ultrasound and polymeric micelles, a new modality (i.e., ultrasound-mediated polymeric micelle drug delivery) has been developed and has recently received increasing attention. A major challenge remaining in developing ultrasound-responsive polymeric micelles is the improvement of the sensitivity or responsiveness of polymeric micelles to ultrasound. This chapter reviews the recent advance in this field. In order to understand the interaction mechanism between ultrasound stimulus and polymeric micelles, ultrasound effects, such as thermal effect, cavitation effect, ultrasound sonochemistry (including ultrasonic degradation, ultrasound-initiated polymerization, ultrasonic in-situ polymerization and ultrasound site-specific degradation), as well as basic micellar knowledge are introduced. Ultrasound-mediated polymeric micelle drug delivery has been classified into two main streams based on the different interaction mechanism between ultrasound and polymeric micelles; one is based on the ultrasound-induced physical disruption of the micelle and reversible release of payload. The other is based on micellar ultrasound mechanochemical disruption and irreversible release of payload.

  19. Simultaneous bench scale production of dissolving grade pulp and valuable hemicelluloses from softwood kraft pulp by ionic liquid extraction.

    PubMed

    Laine, Christiane; Asikainen, Sari; Talja, Riku; Stépán, Agnes; Sixta, Herbert; Harlin, Ali

    2016-01-20

    Ionic liquid extraction of wood pulp has been highlighted as a highly potential new process for dissolving pulp production. Coproduction with a polymeric hemicellulose fraction was demonstrated in bench scale from softwood kraft pulp using extraction with the ionic liquid 1-ethyl-3-methylimidazolium acetate (EMIM OAc) and water. In total, the recovered pulp and hemicellulose fraction together yielded 95.5 wt.% of the pulp input. The extracted pulp had a remarkably high purity with an R18-value of 97.8%. The hemicellulose fraction consisted of galactoglucomannan, arabinoxylan and some cellulose and was precipitated from the ionic liquid-water mixture. After hydroxypropylation of the hemicellulose fraction, films were prepared and barrier and strength properties were compared to films from other polysaccharides. Reduced oxygen and water vapor permeation and good strength properties were demonstrated when compared to corresponding films from hydroxypropylated xylan from cold caustic extraction. The films have potential for applications in food packaging and edible films.

  20. Acceleration and selective monomer addition during aqueous RAFT copolymerization of ionic monomers at 25 °C.

    PubMed

    Li, Guangxiang; Xu, Na; Yu, Qiuping; Lu, Xinhua; Chen, Hong; Cai, Yuanli

    2014-08-01

    An acceleration effect and selective monomer addition during RAFT copolymerization of the oppositely-charged ionic monomers in dilute aqueous solution at 25 °C are reported. The reaction is conducted using a non-ionic water-soluble polymer as a macromolecular chain transfer agent under visible light irradiation. A fast iterative polymerization can be induced, even in dilute solution, by the favorable ionic interactions and in situ self-assembly of zwitterionic growing chains. Selelctive monomer addition is achieved in the statistical copolymerization due to the ion-pairing of the oppositely-charged monomers, such as precisely the same reaction rates at a 1:1 of monomer ratio, otherwise a faster reaction of the minor monomer component over the major one. These behaviors open up an avenue towards the rapid synthesis of sequence-controlled zwitterionic polyelectrolytes that can satisfy the demands of emerging biological applications. PMID:24889131

  1. Simultaneous bench scale production of dissolving grade pulp and valuable hemicelluloses from softwood kraft pulp by ionic liquid extraction.

    PubMed

    Laine, Christiane; Asikainen, Sari; Talja, Riku; Stépán, Agnes; Sixta, Herbert; Harlin, Ali

    2016-01-20

    Ionic liquid extraction of wood pulp has been highlighted as a highly potential new process for dissolving pulp production. Coproduction with a polymeric hemicellulose fraction was demonstrated in bench scale from softwood kraft pulp using extraction with the ionic liquid 1-ethyl-3-methylimidazolium acetate (EMIM OAc) and water. In total, the recovered pulp and hemicellulose fraction together yielded 95.5 wt.% of the pulp input. The extracted pulp had a remarkably high purity with an R18-value of 97.8%. The hemicellulose fraction consisted of galactoglucomannan, arabinoxylan and some cellulose and was precipitated from the ionic liquid-water mixture. After hydroxypropylation of the hemicellulose fraction, films were prepared and barrier and strength properties were compared to films from other polysaccharides. Reduced oxygen and water vapor permeation and good strength properties were demonstrated when compared to corresponding films from hydroxypropylated xylan from cold caustic extraction. The films have potential for applications in food packaging and edible films. PMID:26572370

  2. Gallium and indium complexes containing the bis(imino)phenoxide ligand: synthesis, structural characterization and polymerization studies.

    PubMed

    Ghosh, Swarup; Gowda, Ravikumar R; Jagan, Rajamony; Chakraborty, Debashis

    2015-06-14

    A series of gallium and indium complexes containing a bis(imino)phenolate ligand framework were synthesized and completely characterized with different spectroscopic techniques. The molecular structures of a few complexes were determined using single crystal X-ray diffraction studies. These compounds were found to be extremely active towards the bulk ring opening polymerization (ROP) of lactides yielding polymers with high number average molecular weight (Mn) and controlled molecular weight distributions (MWDs). The neutral complexes produce isotactic enriched poly(lactic acid) (PLA) from rac-lactide (rac-LA) under melt conditions, whereas the ionic complex produces atactic PLA. The polymerizations are controlled, as evidenced by the narrow molecular distribution (MWDs) of the isolated polymers in addition to the linear nature of number average molecular weight (Mn) versus conversion plots with variations in monomer to catalyst ratios. The kinetic and mechanistic studies associated with these polymerizations have been performed.

  3. Chemically modified polymeric resins for high performance liquid chromatography, solid-phase extraction and organic separation by LC and GC

    SciTech Connect

    Sun, Jeffrey Jiafang.

    1991-08-06

    Polystyrene divinylbenzene resins were chemically modified by introduction of various functional groups, which included polar, non-polar, ionic and metallic groups. These chemically modified polymeric resins were used successfully for high performance liquid chromatography, solid phase extraction and some special applications in liquid and gas chromatography. The introduced functional groups offer an additional selectivity parameter for liquid chromatographic separation. The polar derivatized polymeric resins dramatically increased the recoveries of solid phase extraction, especially for polar compounds. The sulfonated polystyrene resins were used for separation of neutral and basic compounds as well as basic and weaker basic compounds. The sulfonated non-porous resin was used amine abstracter and the polymeric-mercuric resin was used as mercaptan abstracter in capillary gas chromatograph. The researches in this dissertation has shown the very promising applications of polystyrene divinylbenzene resin in chromatographic field. 58 refs., 34 figs., 28 tabs.

  4. Performance of solid state supercapacitors based on polymer electrolytes containing different ionic liquids

    NASA Astrophysics Data System (ADS)

    Tiruye, Girum Ayalneh; Muñoz-Torrero, David; Palma, Jesus; Anderson, Marc; Marcilla, Rebeca

    2016-09-01

    Four Ionic Liquid based Polymer Electrolytes (IL-b-PE) were prepared by blending a Polymeric Ionic Liquid, Poly(diallyldimethylammonium) bis(trifluoromethanesulfonyl)imide (PILTFSI), with four different ionic liquids: 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR14TFSI) (IL-b-PE1), 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide (PYR14FSI) (IL-b-PE2), 1-(2-hydroxy ethyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (HEMimTFSI) (IL-b-PE3), and 1-Butyl-1-methylpyrrolidinium dicyanamide, (PYR14DCA) (IL-b-PE4). Physicochemical properties of IL-b-PE such as ionic conductivity, thermal and electrochemical stability were found to be dependent on the IL properties. For instance, ionic conductivity was significantly higher for IL-b-PE2 and IL-b-PE4 containing IL with small size anions (FSI and DCA) than IL-b-PE1 and IL-b-PE3 bearing IL with bigger anion (TFSI). On the other hand, wider electrochemical stability window (ESW) was found for IL-b-PE1 and IL-b-PE2 having ILs with electrochemically stable pyrrolidinium cation and FSI and TFSI anions. Solid state Supercapacitors (SCs) were assembled with activated carbon electrodes and their electrochemical performance was correlated with the polymer electrolyte properties. Best performance was obtained with SC having IL-b-PE2 that exhibited a good compromise between ionic conductivity and electrochemical window. Specific capacitance (Cam), real energy (Ereal) & real power densities (Preal) as high as 150 F g-1, 36 Wh kg-1 & 1170 W kg-1 were found at operating voltage of 3.5 V.

  5. Nanopatterned Protein Films Directed by Ionic Complexation with Water-Soluble Diblock Copolymers

    PubMed Central

    Kim, Bokyung; Lam, Christopher N.; Olsen, Bradley D.

    2014-01-01

    The use of ionic interactions to direct both protein templating and block copolymer self-assembly into nanopatterned films with only aqueous processing conditions is demonstrated using block copolymers containing both thermally responsive and pH responsive blocks. Controlled reversible addition-fragmentation chain-transfer (RAFT) polymerization is employed to synthesize poly(N-isopropylacrylamide-b-2-(dimethylamino)ethyl acrylate) (PNIPAM-b-PDMAEA) diblock copolymers. The pH-dependent ionic complexation between the fluorescent protein, mCherry, and the ionic PDMAEA block is established using dynamic light scattering (DLS) and UV-Vis spectroscopy. DLS shows that the size of the resulting coacervate micelles depends strongly on pH, while UV-Vis spectroscopy shows a correlation between the protein’s absorption maximum and the ionic microenvironment. Zeta potential measurements clearly indicate the ionic nature of the complex-forming interactions. Spin casting was used to prepare nanostructured films from the protein-block copolymer coacervates. After film formation, the lower critical solution temperature (LCST) of the PNIPAM blocks allows the nanomaterial to be effectively immobilized in aqueous environments at physiological temperatures, enabling potential use as a controlled protein release material or polymer matrix for protein immobilization. At pH 9.2 and 7.8, the release rates are at least 10 times faster than that at pH 6.4 due to weaker interaction between protein and PNIPAM-b-PDMAEA (PND) diblock copolymer. Due to the ionic environment in which protein is confined, the majority of the protein (80%) remains active, independent of pH, even after having been dehydrated in vacuum and confined in the films. PMID:24904186

  6. Nanopatterned Protein Films Directed by Ionic Complexation with Water-Soluble Diblock Copolymers.

    PubMed

    Kim, Bokyung; Lam, Christopher N; Olsen, Bradley D

    2012-06-12

    The use of ionic interactions to direct both protein templating and block copolymer self-assembly into nanopatterned films with only aqueous processing conditions is demonstrated using block copolymers containing both thermally responsive and pH responsive blocks. Controlled reversible addition-fragmentation chain-transfer (RAFT) polymerization is employed to synthesize poly(N-isopropylacrylamide-b-2-(dimethylamino)ethyl acrylate) (PNIPAM-b-PDMAEA) diblock copolymers. The pH-dependent ionic complexation between the fluorescent protein, mCherry, and the ionic PDMAEA block is established using dynamic light scattering (DLS) and UV-Vis spectroscopy. DLS shows that the size of the resulting coacervate micelles depends strongly on pH, while UV-Vis spectroscopy shows a correlation between the protein's absorption maximum and the ionic microenvironment. Zeta potential measurements clearly indicate the ionic nature of the complex-forming interactions. Spin casting was used to prepare nanostructured films from the protein-block copolymer coacervates. After film formation, the lower critical solution temperature (LCST) of the PNIPAM blocks allows the nanomaterial to be effectively immobilized in aqueous environments at physiological temperatures, enabling potential use as a controlled protein release material or polymer matrix for protein immobilization. At pH 9.2 and 7.8, the release rates are at least 10 times faster than that at pH 6.4 due to weaker interaction between protein and PNIPAM-b-PDMAEA (PND) diblock copolymer. Due to the ionic environment in which protein is confined, the majority of the protein (80%) remains active, independent of pH, even after having been dehydrated in vacuum and confined in the films. PMID:24904186

  7. Polymerization in the gas phase, in clusters, and on nanoparticle surfaces.

    PubMed

    El-Shall, M Samy

    2008-07-01

    Gas phase and cluster experiments provide unique opportunities to quantitatively study the effects of initiators, solvents, chain transfer agents, and inhibitors on the mechanisms of polymerization. Furthermore, a number of important phenomena, unique structures, and novel properties may exist during gas-phase and cluster polymerization. In this regime, the structure of the growing polymer may change dramatically and the rate coefficient may vary significantly upon the addition of a single molecule of the monomer. These changes would be reflected in the properties of the oligomers deposited from the gas phase. At low pressures, cationic and radical cationic polymerizations may proceed in the gas phase through elimination reactions. In the same systems at high pressure, however, the ionic intermediates may be stabilized, and addition without elimination may occur. In isolated van der Waals clusters of monomer molecules, sequential polymerization with several condensation steps can occur on a time scale of a few microseconds following the ionization of the gas-phase cluster. The cluster reactions, which bridge gas-phase and condensed-phase chemistry, allow examination of the effects of controlled states of aggregation. This Account describes several examples of gas-phase and cluster polymerization studies where the most significant results can be summarized as follows: (1) The carbocation polymerization of isobutene shows slower rates with increasing polymerization steps resulting from entropy barriers, which could explain the need for low temperatures for the efficient propagation of high molecular weight polymers. (2) Radical cation polymerization of propene can be initiated by partial charge transfer from an ionized aromatic molecule such as benzene coupled with covalent condensation of the associated propene molecules. This novel mechanism leads exclusively to the formation of propene oligomer ions and avoids other competitive products. (3) Structural information

  8. Polymerization in the gas phase, in clusters, and on nanoparticle surfaces.

    PubMed

    El-Shall, M Samy

    2008-07-01

    Gas phase and cluster experiments provide unique opportunities to quantitatively study the effects of initiators, solvents, chain transfer agents, and inhibitors on the mechanisms of polymerization. Furthermore, a number of important phenomena, unique structures, and novel properties may exist during gas-phase and cluster polymerization. In this regime, the structure of the growing polymer may change dramatically and the rate coefficient may vary significantly upon the addition of a single molecule of the monomer. These changes would be reflected in the properties of the oligomers deposited from the gas phase. At low pressures, cationic and radical cationic polymerizations may proceed in the gas phase through elimination reactions. In the same systems at high pressure, however, the ionic intermediates may be stabilized, and addition without elimination may occur. In isolated van der Waals clusters of monomer molecules, sequential polymerization with several condensation steps can occur on a time scale of a few microseconds following the ionization of the gas-phase cluster. The cluster reactions, which bridge gas-phase and condensed-phase chemistry, allow examination of the effects of controlled states of aggregation. This Account describes several examples of gas-phase and cluster polymerization studies where the most significant results can be summarized as follows: (1) The carbocation polymerization of isobutene shows slower rates with increasing polymerization steps resulting from entropy barriers, which could explain the need for low temperatures for the efficient propagation of high molecular weight polymers. (2) Radical cation polymerization of propene can be initiated by partial charge transfer from an ionized aromatic molecule such as benzene coupled with covalent condensation of the associated propene molecules. This novel mechanism leads exclusively to the formation of propene oligomer ions and avoids other competitive products. (3) Structural information

  9. Anhydrous Proton Conducting Polymer Electrolyte Membranes via Polymerization-Induced Microphase Separation.

    PubMed

    Chopade, Sujay A; So, Soonyong; Hillmyer, Marc A; Lodge, Timothy P

    2016-03-01

    Solid-state polymer electrolyte membranes (PEMs) exhibiting high ionic conductivity coupled with mechanical robustness and high thermal stability are vital for the design of next-generation lithium-ion batteries and high-temperature fuel cells. We present the in situ preparation of nanostructured PEMs incorporating a protic ionic liquid (IL) into one of the domains of a microphase-separated block copolymer created via polymerization-induced microphase separation. This facile, one-pot synthetic strategy transforms a homogeneous liquid precursor consisting of a poly(ethylene oxide) (PEO) macro-chain-transfer agent, styrene and divinylbenzene monomers, and protic IL into a robust and transparent monolith. The resulting PEMs exhibit a bicontinuous morphology comprising PEO/protic IL conducting pathways and highly cross-linked polystyrene (PS) domains. The cross-linked PS mechanical scaffold imparts thermal and mechanical stability to the PEMs, with an elastic modulus approaching 10 MPa at 180 °C, without sacrificing the ionic conductivity of the system. Crucially, the long-range continuity of the PEO/protic IL conducting nanochannels results in an outstanding ionic conductivity of 14 mS/cm at 180 °C. We posit that proton conduction in the protic IL occurs via the vehicular mechanism and the PEMs exhibit an average proton transference number of 0.7. This approach is very promising for the development of high-temperature, robust PEMs with excellent proton conductivities. PMID:26927732

  10. Ultrastable Superbase-Derived Protic Ionic Liquids

    SciTech Connect

    Luo, Huimin; Baker, Gary A.; Lee, Je Seung; Pagni, Richard M.; Dai, Sheng

    2009-04-02

    Protic ionic liquids are synthesized via proton transfer from acids to organic bases. One of the key issues associated with conventional protic ionic liquids is the thermal instability resulting from temperature-induced decomposition via reverse proton transfer. This shortcoming significantly hampers the use of these protic ionic liquids in separations, electrochemical capacitors, fuel cells, and so forth. Herein we show that it is possible to prepare protic ionic liquids with thermal stabilities approaching those of common aprotic ionic liquids. Our new class of protic ionic liquids, derived via integrated neutralization and metathesis of superbasic phosphazenes or guanidines, exhibits exceptionally low vapor pressures at 150 °C while being stable to strong alkali agents such as aqueous KOH, suggesting potential in energy-related applications, including electrochemical capacitors and PEM-type fuel cells.

  11. The advantage of polymer addition to a non-ionic oil in water microemulsion for the dermal delivery of progesterone.

    PubMed

    Biruss, Babette; Valenta, Claudia

    2008-02-12

    The influence of progesterone on the physicochemical behaviour of the o/w microemulsion consisting of the non-ionic surfactant polyoxyethylene-10-dodecyl ether, tributyrin and water was investigated. Thereby no significant influence could be detected in terms of droplet size, zeta potential, conductivity and pH by progesterone. However the chemical stability of progesterone was insufficient during the storage of 6 months. Therefore, two different polymeric agents, named silicon dioxide and polymeric emulsifier, were added to the progesterone containing microemulsions. These polymers increased the chemical stability of progesterone significantly. Moreover the polymeric additives improved the skin permeation 1.24- and 1.63-fold and decreased the skin retention in relation to the pure microemulsion. The polymer-stabilized progesterone microemulsions are interesting vehicles for skin application of progesterone. PMID:17869457

  12. Methoxyethoxyethoxyphosphazenes as ionic conductive fire retardant additives for lithium battery systems

    NASA Astrophysics Data System (ADS)

    Fei, Shih-To; Allcock, Harry R.

    The current highly flammable configurations for rechargeable lithium batteries generate safety concerns. Although commercial fire retardant additives have been investigated, they tend to decrease the overall efficiency of the battery. We report here ionically conductive, non-halogenated lithium battery additives based on a methoxyethoxyethoxyphosphazene oligomer and the corresponding high polymer, which can increase the fire resistance of a battery while retaining a high energy efficiency. Conductivities in the range of 10 -4 S cm -1 have been obtained for self-extinguishing, ion-conductive methoxyethoxyethoxyphosphazene oligomers. The addition of 25 wt% high polymeric poly[bis(methoxyethoxyethoxy)phosphazene] to propylene carbonate electrolytes lowers the flammability by 90% while maintaining a good ionic conductivity of 2.5 × 10 -3 S cm -1.

  13. Crosslinked polymer gel electrolytes based on polyethylene glycol methacrylate and ionic liquid for lithium battery applications

    SciTech Connect

    Liao, Chen; Sun, Xiao-Guang; Dai, Sheng

    2013-01-01

    Gel polymer electrolytes were synthesized by copolymerization polyethylene glycol methyl ether methacrylate with polyethylene glycol dimethacrylate in the presence of a room temperature ionic liquid, methylpropylpyrrolidinium bis(trifluoromethanesulfonyl)imide (MPPY TFSI). The physical properties of gel polymer electrolytes were characterized by thermal analysis, impedance spectroscopy, and electrochemical tests. The ionic conductivities of the gel polymer electrolytes increased linearly with the amount of MPPY TFSI and were mainly attributed to the increased ion mobility as evidenced by the decreased glass transition temperatures. Li||LiFePO4 cells were assembled using the gel polymer electrolytes containing 80 wt% MPPY TFSI via an in situ polymerization method. A reversible cell capacity of 90 mAh g 1 was maintained under the current density of C/10 at room temperature, which was increased to 130 mAh g 1 by using a thinner membrane and cycling at 50 C.

  14. Preparation of corn starch-g-polystyrene copolymer in ionic liquid: 1-ethyl-3-methylimidazolium acetate.

    PubMed

    Men, Yongjun; Du, Xiyan; Shen, Jianan; Wang, Leli; Liu, Zhengping

    2015-05-01

    The copolymer of starch grafted with polystyrene (starch-g-PS) was synthesized with high grafting percentage by utilizing the ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIM]Ac) as solvent and potassium persulfate as initiator. The effect of various parameters upon the polymerization were studied including: initiator concentration, styrene:starch weight ratio, the reaction time and temperature. Grafting percentages were calculated using an FT-IR calibration method, with values up to 114%. The resulting copolymer was characterized using FT-IR, SEM, WAXD and TGA, which demonstrated that polystyrene side chains were evenly distributed on the starch backbone. Our results indicate that ionic liquid dissolution of starch, prior to polystyrene grafting, is a versatile methodology for the synthesis of amphiphilic, polysaccharide-based graft copolymers, having high grafting percent. PMID:25659709

  15. Ionic liquid promoted synthesis of conjugated carbon nitride photocatalysts from urea.

    PubMed

    Lin, Zhenzhen; Wang, Xinchen

    2014-06-01

    To allow for simultaneous textural engineering and doping of carbon nitride materials with heteroatoms, urea has been polymerized with an ionic liquid. The role of urea is to create a delamination effect during carbon nitride synthesis, whereas ionic liquid functions as texture modifier as well as B/F dopant source. This will result in the rational fabrication of boron- and fluorine-containing 2D carbon nitride nanosheets with enhanced optical harvesting and charge separation capabilities for hydrogen evolution catalysis using visible light. We believe that the innovative modification strategy developed herein can be coupled with the already known modification tools of 2D carbon nitride, thus further developing a new family of light-harvesting 2D platforms for the efficient and sustained utilization of solar radiation for a variety of advanced applications, including CO2 photofixation, organic photosynthesis, and pollutant controls. PMID:24692300

  16. Investigation of Ionic Conductivity of - MgCl2 Based Solid Polymer Electrolyte

    NASA Astrophysics Data System (ADS)

    Sundar, M.; Poovizhi, P. N.; Arunkarthikeyan, J.; Selladurai, S.

    2006-06-01

    Novel solid polymeric electrolyte (SPE) consisting of Poly (ethylene oxide) PEO with magnesium chloride as the electrolyte salt has been prepared by solution casting technique. Measurements with differential scanning calorimetry (DSC) indicates the modification of PEO crystalline structure with increasing content of magnesium salt up to 20 wt% and increase in crystallinity at higher concentration. FTIR studies indicates the interaction of Mg cations with ether oxygen of PEO, Ionic conductivity increases with increase in salt content, and it is optimized at 20 wt% Mg salt. The decrease in ionic conductivity at higher salt content above 20 wt% is due to ion-ion interaction, which leads to ion pair formation and increase in relative crystallanity fraction due to recrystallization above 15wt%.

  17. Ionic liquid promoted synthesis of conjugated carbon nitride photocatalysts from urea.

    PubMed

    Lin, Zhenzhen; Wang, Xinchen

    2014-06-01

    To allow for simultaneous textural engineering and doping of carbon nitride materials with heteroatoms, urea has been polymerized with an ionic liquid. The role of urea is to create a delamination effect during carbon nitride synthesis, whereas ionic liquid functions as texture modifier as well as B/F dopant source. This will result in the rational fabrication of boron- and fluorine-containing 2D carbon nitride nanosheets with enhanced optical harvesting and charge separation capabilities for hydrogen evolution catalysis using visible light. We believe that the innovative modification strategy developed herein can be coupled with the already known modification tools of 2D carbon nitride, thus further developing a new family of light-harvesting 2D platforms for the efficient and sustained utilization of solar radiation for a variety of advanced applications, including CO2 photofixation, organic photosynthesis, and pollutant controls.

  18. A multifunctional azobenzene-based polymeric adsorbent for effective water remediation

    NASA Astrophysics Data System (ADS)

    Wan, Decheng; Chen, Feng; Geng, Qingrui; Lu, Hang; Willcock, Helen; Liu, Qiuming; Wang, Fangyingkai; Zou, Kaidian; Jin, Ming; Pu, Hongting; Du, Jianzhong

    2014-12-01

    The efficient removal of trace carcinogenic organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs) and ionic dyes, from water is an important technical challenge. We report a highly effective recyclable multifunctional azobenzene (AZ)-based silica-supported polymeric adsorbent which can simultaneously remove both PAHs and anionic dyes from water to below parts per billion (ppb) level based on multiple interactions such as the hydrophobic effect, π-π stacking and electrostatic interactions, thus providing a new strategy for designer water remediation materials.

  19. Early Events in Ionic Liquid Radiation Chemistry

    SciTech Connect

    Wishart, J.F.; Cook, A.; Rimmer, R.D.; Gohdo, M.

    2010-09-14

    Ionic liquids are interesting and useful materials whose solvation time scales are up to thousands of times longer than in conventional solvents. The extended lifetimes of pre-solvated electrons and other energetic species in ionic liquids has profound consequences for the radiolytic product distributions and reactivity patterns. We use a newly developed, multiplexed variation of pulse-probe spectroscopy to measure the kinetics of the early dynamical and reactive events in ionic liquids.

  20. Structural insights into de novo actin polymerization

    PubMed Central

    Dominguez, Roberto

    2010-01-01

    Summary Many cellular functions depend on rapid and localized actin polymerization/depolymerization. Yet, the de novo polymerization of actin in cells is kinetically unfavorable because of the instability of polymerization intermediates (small actin oligomers) and the actions of actin monomer binding proteins. Cells use filament nucleation and elongation factors to initiate and sustain polymerization. Structural biology is beginning to shed light on the diverse mechanisms by which these unrelated proteins initiate polymerization, undergo regulation, and mediate the transition of monomeric actin onto actin filaments. A prominent role is played by the W domain, which in some of these proteins occurs in tandem repeats that recruit multiple actin subunits. Pro-rich regions are also abundant and mediate the binding of profilin-actin complexes, which are the main source of polymerization competent actin in cells. Filament nucleation and elongation factors frequently interact with Rho family GTPases, which relay signals from membrane receptors to regulate actin cytoskeleton remodeling. PMID:20096561

  1. Internal Morphology-Controllable Self-Assembly in Poly(Ionic Liquid) Nanoparticles.

    PubMed

    Zhang, Weiyi; Kochovski, Zdravko; Lu, Yan; Schmidt, Bernhard V K J; Antonietti, Markus; Yuan, Jiayin

    2016-08-23

    Precise control of the interior and outer shapes of polymer nanoparticles has found broad interest in nanosciences, for example, in fundamental studies of their physical properties, colloidal behavior, and corresponding applications. Realizing such control below the 50 nm scale (i.e., a size scale close to individual polymer chains) requires accurate manipulation of polymerization techniques and a judicious choice of the chemical structure in monomers and/or polymers. Here, we constructed a series of well-defined sub-50 nm homopolymer nanoparticles with controllable shape and highly ordered, complex internal structures with sub-5 nm domain spacings, starting from 1-vinyl-1,2,4-triazolium-type ionic liquids in a one-pot dispersion polymerization. With cryogenic electron microscopy and tomography, a morphological evolution of particle shape and interior at this extremely small size end, unusual for polymer colloids, was identified and investigated in detail. PMID:27501014

  2. Segmented heat exchanger

    DOEpatents

    Baldwin, Darryl Dean; Willi, Martin Leo; Fiveland, Scott Byron; Timmons, Kristine Ann

    2010-12-14

    A segmented heat exchanger system for transferring heat energy from an exhaust fluid to a working fluid. The heat exchanger system may include a first heat exchanger for receiving incoming working fluid and the exhaust fluid. The working fluid and exhaust fluid may travel through at least a portion of the first heat exchanger in a parallel flow configuration. In addition, the heat exchanger system may include a second heat exchanger for receiving working fluid from the first heat exchanger and exhaust fluid from a third heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the second heat exchanger in a counter flow configuration. Furthermore, the heat exchanger system may include a third heat exchanger for receiving working fluid from the second heat exchanger and exhaust fluid from the first heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the third heat exchanger in a parallel flow configuration.

  3. From molten salts to ionic liquids: a "nano" journey.

    PubMed

    Dupont, Jairton

    2011-11-15

    Ionic liquids (ILs), a special group of classical molten salts, are widely used in various fields of science. Historically, researchers have tested ILs out of curiosity or to improve a specific property in a particular system in many areas of chemistry or materials science. However, today, ILs are far from being simple chemical curiosities and sit at the center of various green industrial innovation processes, where they play important roles in materials extraction, reactive catalytic supports, spatial devices, and biotransformations. In this Account, we describe a journey into a nanostructured universe to better understand the unique properties of ionic liquids and their modern applications. Because molten salts have been known for centuries and have found limited uses, we try to explain why modern nonaqueous ILs deserve increased interest and curiosity. We discuss the characteristics that distinguish modern nonaqueous ILs and compare them with classical molten salts. One of the main differences between room temperature ILs, especially those based on imidazolium cations, and simple molten salts, is the molecular asymmetry built into at least one of the ions. This asymmetry in modern, nonaqueous ILs opposes the strong charge ordering due to ionic interactions that normally would cause the system to crystallize. In addition, the presence of a cooperative network of hydrogen bonds between the cations and anions induces structural directionality (the entropic effect). Therefore, modern ILs form preorganized structures, mainly through hydrogen bonding, that induce structural directionality. In contrast, classical salts form aggregates only through ionic bonds. In other words, weak interactions order the structures in modern ILs while charges order the structure within classical salts. ILs cannot be regarded as merely homogeneous solvents. In fact, ILs form extended hydrogen-bond networks with polar and nonpolar nano domains and therefore are by definition

  4. Utilizing advanced polymerization techniques for simplifying polymer grafting from silica colloidal crystal substrates

    NASA Astrophysics Data System (ADS)

    Yerneni, Charu K.

    Polyacrylamide has been well established as a biocompatible material when Polyacrylamide gel electrophoresis (PAGE) came into existence in the 1960s. Under aqueous buffer conditions it becomes non-adsorptive to proteins and due to its molecular level pore forming nature could be used in size based biomolecule separations. Since then considerable research has been done to explore the non-adsorptive nature of polyacrylamide on a platform or substrate. Attempts were made to grow polyacrylamide chains from silica as a substrate which can then be used in various protein separation techniques. Based on an ionic polymerization method which was used for gel casting in PAGE, polymers were grown on silica gel. Though considerable thickness could be achieved, polymerization was not just confined to the surface. Therefore a rigid polymer brush layer could not be achieved. Atom transfer radical polymerization (ATRP) method showed the solution to this problem. Polymer brush layers with acceptable thickness could now be achieved for growing polyacrylamide from silica gel. Yet it still suffered from several disadvantages such as the need of an inert atmosphere for polymerization and limited thickness. Many developments have taken place in the past decade which led to improvements in substrate and polymerization methods. This research used non porous sub-micron silica as the substrate and AGET ATRP (Activator generated electron transfer atom transfer radical polymerization) for surface grafting polyacrylamide. Non porous submicron silica has been shown to be a better stationary phase substrate for protein separations than conventional substrates. AGET ATRP enables polymerization to be performed under ambient conditions and in water based solutions which gives thicknesses much higher than conventional ATRP. Data from various analytical techniques showed that within the experimental range the polymerization is linear and has decent control. This means silica nanoparticles coated with

  5. Ionic contrast terahertz near-field imaging of axonal activity and water fluxes

    NASA Astrophysics Data System (ADS)

    Masson, Jean-Baptiste; Sauviat, Martin-Pierre; Martin, Jean-Louis; Gallot, Guilhem

    2007-02-01

    We demonstrated the direct and noninvasive imaging of functional neurons,1 as well as auricular heart muscle electrical activity2 by Ionic Contrast Terahertz (ICT) near-field microscopy. This technique provides quantitative measurements of ionic concentrations in both the intracellular and extracellular compartments and opens the way to direct noninvasive imaging of neurons during electrical, toxin, or thermal stresses. Furthermore, neuronal activity results from both a precise control of transient variations in ionic conductances and a much less studied water exchange between the extracellular matrix and the intraaxonal compartment. The developed ICT technique associated with a full three-dimensional simulation of the axon-aperture near-field system allows a precise measurement of the axon geometry and therefore the direct visualization of neuron swelling induced by temperature change or neurotoxin poisoning. This technique should then provide grounds for the development of advanced functional neuroimaging methods based on diffusion anisotropy of water molecules.

  6. Ionene modified small polymeric beads

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor)

    1977-01-01

    Linear ionene polyquaternary cationic polymeric segments are bonded by means of the Menshutkin reaction (quaternization) to biocompatible, extremely small, porous particles containing halide or tertiary amine sites which are centers for attachment of the segments. The modified beads in the form of emulsions or suspensions offer a large, positively-charged surface area capable of irreversibly binding polyanions such as heparin, DNA, RNA or bile acids to remove them from solution or of reversibly binding monoanions such as penicillin, pesticides, sex attractants and the like for slow release from the suspension.

  7. Marketing NASA Langley Polymeric Materials

    NASA Technical Reports Server (NTRS)

    Flynn, Diane M.

    1995-01-01

    A marketing tool was created to expand the knowledge of LaRC developed polymeric materials, in order to facilitate the technology transfer process and increase technology commercialization awareness among a non-technical audience. The created brochure features four materials, LaRC-CP, LaRC-RP46, LaRC-SI, and LaRC-IA, and highlights their competitive strengths in potential commercial applications. Excellent opportunities exist in the $40 million per year microelectronics market and the $6 billion adhesives market. It is hoped that the created brochure will generate inquiries regarding the use of the above materials in markets such as these.

  8. Electrically controlled polymeric gel actuators

    DOEpatents

    Adolf, D.B.; Shahinpoor, M.; Segalman, D.J.; Witkowski, W.R.

    1993-10-05

    Electrically controlled polymeric gel actuators or synthetic muscles are described capable of undergoing substantial expansion and contraction when subjected to changing pH environments, temperature, or solvent. The actuators employ compliant containers for the gels and their solvents. The gels employed may be cylindrical electromechanical gel fibers such as polyacrylamide fibers or a mixture of poly vinyl alcohol-polyacrylic acid arranged in a parallel aggregate and contained in an electrolytic solvent bath such as salt water. The invention includes smart, electrically activated devices exploiting this phenomenon. These devices are capable of being manipulated via active computer control as large displacement actuators for use in adaptive structure such as robots. 11 figures.

  9. Computational studies of polymeric systems

    NASA Astrophysics Data System (ADS)

    Carrillo, Jan-Michael Y.

    Polymeric systems involving polyelectrolytes in surfaces and interfaces, semiflexible polyelectrolytes and biopolymers in solution, complex polymeric systems that had applications in nanotechnology were modeled using coarse grained molecular dynamics simulation. In the area of polyelectrolytes in surfaces and interfaces, the phenomena of polyelectrolyte adsorption at oppositely charge surface was investigated. Simulations found that short range van der Waals interaction was a major factor in determining morphology and thickness of the adsorbed layer. Hydrophobic polyelectrolytes adsorbed in hydrophobic surfaces tend to be the most effective in forming multi-layers because short range attraction enhances the adsorption process. Adsorbed polyelectrolytes could move freely along the surface which was in contrast to polyelectrolyte brushes. The morphologies of hydrophobic polyelectrolyte brushes were investigated and simulations found that brushes had different morphologies depending on the strength of the short range monomer-monomer attraction, electrostatic interaction and counterion condensation. Planar polyelectrolyte brushes formed: (1) vertically oriented cylindrical aggregates, (2) maze-like aggregate structures, or (3) thin polymeric layer covering a substrate. While, the spherical polyelectrolyte brushes could be in any of the previous morphologies or be in a micelle-like conformation with a dense core and charged corona. In the area of biopolymers and semiflexible polyelectrolytes in solution, simulations demonstrated that the bending rigidity of these polymers was scale-dependent. The bond-bond correlation function describing a chain's orientational memory could be approximated by a sum of two exponential functions manifesting the existence of the two characteristic length scales. The existence of the two length scales challenged the current practice of describing chain stretching experiments using a single length scale. In the field of nanotechnology

  10. Multicomponent diffusion in polymeric liquids.

    PubMed Central

    Curtiss, C F; Bird, R B

    1996-01-01

    It is shown how the phase-space kinetic theory of polymeric liquid mixtures leads to a set of extended Maxwell-Stefan equations describing multicomponent diffusion. This expression reduces to standard results for dilute solutions and for undiluted polymers. The polymer molecules are modeled as flexible bead-spring structures. To obtain the Maxwell-Stefan equations, the usual expression for the hydrodynamic drag force on a bead, used in previous kinetic theories, must be replaced by a new expression that accounts explicitly for bead-bead interactions between different molecules. PMID:11607693

  11. Electrically controlled polymeric gel actuators

    DOEpatents

    Adolf, Douglas B.; Shahinpoor, Mohsen; Segalman, Daniel J.; Witkowski, Walter R.

    1993-01-01

    Electrically controlled polymeric gel actuators or synthetic muscles capable of undergoing substantial expansion and contraction when subjected to changing pH environments, temperature, or solvent. The actuators employ compliant containers for the gels and their solvents. The gels employed may be cylindrical electromechanical gel fibers such as polyacrylamide fibers or a mixture of poly vinyl alcohol-polyacrylic acid arranged in a parallel aggregate and contained in an electrolytic solvent bath such as salt water. The invention includes smart, electrically activated devices exploiting this phenomenon. These devices are capable of being manipulated via active computer control as large displacement actuators for use in adaptive structure such as robots.

  12. Ionic versus nonionic contrast use.

    PubMed

    Stolberg, H O; McClennan, B L

    1991-01-01

    It has taken many years of research, development and intense scientific investigation to produce intravascular contrast media. Research on relations between chemical structure, animal toxicity, and water-solubility has produced a number of highly water-soluble, iodinated compounds for use in diagnostic radiology as intravascular contrast agents. The currently used intravascular agents may be classified into four groups according to their chemical structure: 1. Ionic monomers 2. Ionic monoacid dimers 3. Nonionic monomers 4. Nonionic dimers It is the objective of this publication to review the history and development of intravascular contrast media as well as their properties, general effects and clinical use. The four types of contrast media differ significantly in their chemical structure and physico-chemical properties, and these differences determine their osmotoxicity, chemotoxicity, and ion toxicity. We analyze the organ specific toxic effects of intravascular contrast media upon the central nervous system, the cardiovascular system, and the renal system. We also review the secondary effects, clinical manifestations, and the incidence of adverse events associated with different types of contrast. The choice of contrast media has become critical since the introduction of nonionic agents because their toxicological and pharmacological properties differ from those of the ionic agents. The application of basic concepts involved in the use of contrast media in excretory urography, computed tomography, angiography, and angiocardiography is discussed, and the advantages of the use of nonionic contrast agents are outlined. Economic and ethical issues are presented with emphasis upon strategies to reduce the risk associated with the injection of intravascular contrast and to curtail consumption according to rational principles of use. PMID:2049958

  13. Stabilization of extracellular polymeric substances ( Bacillus subtilis) by adsorption to and coprecipitation with Al forms

    NASA Astrophysics Data System (ADS)

    Mikutta, Robert; Zang, Ulrich; Chorover, Jon; Haumaier, Ludwig; Kalbitz, Karsten

    2011-06-01

    Extracellular polymeric substances (EPS) are continuously produced by bacteria during their growth and metabolism. In soils, EPS are bound to cell surfaces, associated with biofilms, or released into solution where they can react with other solutes and soil particle surfaces. If such reaction results in a decrease in EPS bioaccessibility, it may contribute to stabilization of microbial-derived organic carbon (OC) in soil. Here we examined: (i) the chemical fractionation of EPS produced by a common Gram positive soil bacterial strain ( Bacillus subtilis) during reaction with dissolved and colloidal Al species and (ii) the resulting stabilization against desorption and microbial decay by the respective coprecipitation (with dissolved Al) and adsorption (with Al(OH) 3(am)) processes. Coprecipitates and adsorption complexes obtained following EPS-Al reaction as a function of pH and ionic strength were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The stability of adsorbed and coprecipitated EPS against biodegradation was assessed by mineralization experiments for 1100 h. Up to 60% of the initial 100 mg/L EPS-C was adsorbed at the highest initial molar Al:C ratio (1.86), but this still resulted only in a moderate OC mass fraction in the solid phase (17 mg/g Al(OH) 3(am)). In contrast, while coprecipitation by Al was less efficient in removing EPS from solution (maximum values of 33% at molar Al:C ratios of 0.1-0.2), the OC mass fraction in the solid product was substantially larger than that in adsorption complexes. Organic P compounds were preferentially bound during both adsorption and coprecipitation. Data are consistent with strong ligand exchange of EPS phosphoryl groups during adsorption to Al(OH) 3(am), whereas for coprecipitation weaker sorption mechanisms are also involved. X-ray photoelectron analyses indicate an intimate mixing of EPS with Al in the coprecipitates, which is not observed in the case

  14. Mean-field description of ionic size effects with nonuniform ionic sizes: a numerical approach.

    PubMed

    Zhou, Shenggao; Wang, Zhongming; Li, Bo

    2011-08-01

    Ionic size effects are significant in many biological systems. Mean-field descriptions of such effects can be efficient but also challenging. When ionic sizes are different, explicit formulas in such descriptions are not available for the dependence of the ionic concentrations on the electrostatic potential, that is, there is no explicit Boltzmann-type distributions. This work begins with a variational formulation of the continuum electrostatics of an ionic solution with such nonuniform ionic sizes as well as multiple ionic valences. An augmented Lagrange multiplier method is then developed and implemented to numerically solve the underlying constrained optimization problem. The method is shown to be accurate and efficient, and is applied to ionic systems with nonuniform ionic sizes such as the sodium chloride solution. Extensive numerical tests demonstrate that the mean-field model and numerical method capture qualitatively some significant ionic size effects, particularly those for multivalent ionic solutions, such as the stratification of multivalent counterions near a charged surface. The ionic valence-to-volume ratio is found to be the key physical parameter in the stratification of concentrations. All these are not well described by the classical Poisson-Boltzmann theory, or the generalized Poisson-Boltzmann theory that treats uniform ionic sizes. Finally, various issues such as the close packing, limitation of the continuum model, and generalization of this work to molecular solvation are discussed. PMID:21929014

  15. Ketoprofen as a photoinitiator for anionic polymerization.

    PubMed

    Wang, Yu-Hsuan; Wan, Peter

    2015-06-01

    A new photoinitiating system for anionic polymerization of acrylates based on the efficient photodecarboxylation of Ketoprofen (1) and the related derivatives 3 and 4 that generate the corresponding carbanion intermediates is presented. Carbanion intermediates are confirmed by deuterium incorporation in the trapped Michael adducts and by spectroscopic detection using laser flash photolysis (LFP). This novel anionic initiating system features excitation in the near UV and visible regions, potential characteristics of photocontrolled living polymerization, and metal-free photoinitiators generated from photoexcitation, different from typical anionic polymerization where the polymerizations are initiated by heat and strong base containing alkali metals.

  16. Ionic Coulomb Blockade in Nanopores

    PubMed Central

    Krems, Matt; Di Ventra, Massimiliano

    2014-01-01

    Understanding the dynamics of ions in nanopores is essential for applications ranging from single-molecule detection to DNA sequencing. We show both analytically and by means of molecular dynamics simulations that under specific conditions ion-ion interactions in nanopores lead to the phenomenon of ionic Coulomb blockade, namely the build-up of ions inside a nanopore with specific capacitance impeding the flow of additional ions due to Coulomb repulsion. This is the counterpart of electronic Coulomb blockade observed in mesoscopic systems. We discuss the analogies and differences with the electronic case as well as experimental situations in which this phenomenon could be detected. PMID:23307655

  17. Active musculoskeletal structures equipped with a circulatory system and a network of ionic polymeric gel muscles

    SciTech Connect

    Shahinpoor, M.; Mojarrad, M.

    1994-12-31

    Presented are descriptions of design and fabrication of an active musculoskeletal structure composed of an artificial human skeleton of 5.3 feet in height. This skeletal structure is further equipped with an artificial heart in the form of a multi-channel computer-controlled fluid pump. The fluid pump may be programmed to selectively pump either an acid, a base or de-ionized water to a network of veins that feed a network of pairs of antagonist contractile synthetic muscles. These muscles are manufactured in the laboratory from polyacrylonitrile (PAN) fiber bundles that are specially designed and packaged inside flexible, hyperelastic latex membranes. Each pair of muscles act as a pair of antagonist actuator similar to the biceps and triceps muscles of the human arm. The initial fabrication indicates that it is possible to dynamically control such active musculoskeletal structures. A model is also presented for the dynamic control of such antagonist muscles. The model is intended to be used to study the human musculoskeletal dynamics.

  18. Acrylate intercalation and in situ polymerization in iron-, cobalt-, or manganese-substituted nickel hydroxides.

    PubMed

    Vaysse, C; Guerlou-Demourgues, L; Duguet, E; Delmas, C

    2003-07-28

    A chimie douce route based on successive redox and exchange reactions has allowed us to prepare new hybrid organic-inorganic materials, composed of polyacrylate macromolecules intercalated into layered double hydroxides (LDHs), deriving from Ni(OH)(2). Monomer intercalation and in situ polymerization mechanisms have appeared to be strongly dependent upon the nature of the substituting cation in the slabs. In the case of iron-based LDHs, a phase containing acrylate monomeric intercalates has been isolated and identified by X-ray diffraction and infrared spectroscopy. Second, interslab free-radical polymerization of acrylate anions has been successfully initiated using potassium persulfate. In cobalt- or manganese-based LDHs, one-step polymerization has been observed, leading directly to a material containing polyacrylate intercalate. PMID:12870945

  19. Educator Exchange Resource Guide.

    ERIC Educational Resources Information Center

    Garza, Cris; Rodriguez, Victor

    This resource guide was developed for teachers and administrators interested in participating in intercultural and international exchange programs or starting an exchange program. An analysis of an exchange program's critical elements discusses exchange activities; orientation sessions; duration of exchange; criteria for participation; travel,…

  20. Ionic Liquids in Capillary Electrophoresis.

    PubMed

    Holzgrabe, Ulrike; Wahl, Joachim

    2016-01-01

    Recently, a great interest was drawn toward ionic liquids (ILs) in analytical separation techniques. ILs possess many properties making them excellent additives in capillary electrophoresis (CE) background electrolytes (BGE). The most important property is the charge of the dissolved ions in BGE enabling the cations to interact with deprotonated silanol groups on the capillary surface and thereby modifying the electroosmotic flow (EOF). Ionic and/or proton donor-acceptor interactions between analyte and IL are possible interactions facilitating new kinds of separation mechanisms in CE. Further advantages of ILs are the high conductivity, the environmentally friendliness, and the good solubility for organic and inorganic compounds. The most commonly used ILs in capillary electrophoresis are dialkylimidazolium-based ILs, whereas for enantioseparation a lot of innovative chiral cations and anions were investigated.ILs are reported to be additives to a normal CE background electrolyte or the sole electrolyte in CE, nonaqueous CE (NACE), micellar electrokinetic chromatography (MEKC), and in enantioseparation. An overview of applications and separation mechanisms reported in the literature is given here, in addition to the enantioseparation of pseudoephedrine using tetrabutylammonium chloride (TBAC) as IL additive to an ammonium formate buffer containing β-cyclodextrin (β-CD). PMID:27645735

  1. Ionic effects on spindle adaptation

    PubMed Central

    Husmark, I.; Ottoson, D.

    1971-01-01

    1. Effects of changes in ionic environment on the receptor potential were studied in isolated frog spindle. Particular attention was focused on the action of potassium removal on the early adaptive decline of the response. 2. Removal of potassium caused a reduction and final disappearance of the dynamic overshoot of the receptor potential. The static phase of the response was also reduced although to less extent. The repolarization phase of the response following release of phasic or maintained stretch was greatly prolonged. 3. Increased potassium concentration caused a reduction of the response, but did not change its general time course. The amount of reduction was related to the potassium concentration. 4. Removal of sodium caused a marked diminution of the response, the static phase being in general more affected than the dynamic phase. 5. It is suggested that the effects of potassium removal are caused by a delay in sodium inactivation and a partial depolarization of the endings. It is concluded that the greater part of the early adaptation of the spindle proper may be attributed to ionic mechanisms in the transducer membrane. PMID:4256546

  2. Ionic liquid tunes microemulsion curvature.

    PubMed

    Liu, Liping; Bauduin, Pierre; Zemb, Thomas; Eastoe, Julian; Hao, Jingcheng

    2009-02-17

    Middle-phase microemulsions formed from cationic dioctadecyldimethylammonium chloride (DODMAC), anionic sodium dodecylsulfate (SDS), n-butanol, and n-heptane were studied. An ionic liquid (IL), 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]), was employed as the electrolyte in the aqueous media instead of inorganic salts usually used in microemulsion formulation. Studies have been carried out as a function of the concentrations of [bmim][BF4], n-butanol, total surfactant (cDODMAC+SDS), and temperature on the phase behavior and the ultralow interfacial tensions in which the anionic component is present in excess in the catanionic film. Ultralow interfacial tension measurements confirmed the formation of middle-phase microemulsions and the necessary conditions for stabilizing middle-phase microemulsions. Electrical conductivity, small-angle X-ray scattering (SAXS), and small-angle neutron scattering (SANS) experiments were also performed, indicating that the typical heptane domain size has an average radius of 360 A and the ionic liquid induces softening of the charged catanionic film. Most interestingly, the IL concentration (cIL) is shown to act as an effective interfacial curvature-control parameter, representing a new approach to tuning the formulation of microemulsions and emulsions. The results expand the potential uses of ILs but also point to the design of new ILs that may achieve superefficient control over interfacial and self-assembly systems. PMID:19161325

  3. Fixation of radioactive ions in porous media with ion exchange gels

    DOEpatents

    Mercer, Jr., Basil W.; Godfrey, Wesley L.

    1979-01-01

    A method is provided for fixing radioactive ions in porous media by injecting into the porous media water-soluble organic monomers which are polymerizable to gel structures with ion exchange sites and polymerizing the monomers to form ion exchange gels. The ions and the particles of the porous media are thereby physically fixed in place by the gel structure and, in addition, the ions are chemically fixed by the ion exchange properties of the resulting gel.

  4. Trace element partition coefficient in ionic crystals.

    PubMed

    Nagasawa, H

    1966-05-01

    Partition coefficient monovalent trace ions between liquids and either solid NaNO(2) or KCl were determined. The isotropic elastic model of ionic crystals was used for calculating the energy change caused by the ionic substitutions. The observed values of partition coefficients in KCl good agreement with calculate values.

  5. Engineered microorganisms having resistance to ionic liquids

    DOEpatents

    Ruegg, Thomas Lawrence; Thelen, Michael P.

    2016-03-22

    The present invention provides for a method of genetically modifying microorganisms to enhance resistance to ionic liquids, host cells genetically modified in accordance with the methods, and methods of using the host cells in a reaction comprising biomass that has been pretreated with ionic liquids.

  6. Ionic liquid-in-oil microemulsions.

    PubMed

    Eastoe, Julian; Gold, Sarah; Rogers, Sarah E; Paul, Alison; Welton, Tom; Heenan, Richard K; Grillo, Isabelle

    2005-05-25

    Phase stability and small-angle neutron scattering (SANS) data show that surfactant-stabilized nanodomains of a typical ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate [bmim][BF4]) may be dispersed by the nonionic surfactant Triton-X100 in cyclohexane. Analyses of these SANS data are consistent with the formation of ionic liquid-in-oil microemulsion droplets. PMID:15898765

  7. VOLUMETRIC POLYMERIZATION SHRINKAGE OF CONTEMPORARY COMPOSITE RESINS

    PubMed Central

    Nagem, Halim; Nagem, Haline Drumond; Francisconi, Paulo Afonso Silveira; Franco, Eduardo Batista; Mondelli, Rafael Francisco Lia; Coutinho, Kennedy Queiroz

    2007-01-01

    The polymerization shrinkage of composite resins may affect negatively the clinical outcome of the restoration. Extensive research has been carried out to develop new formulations of composite resins in order to provide good handling characteristics and some dimensional stability during polymerization. The purpose of this study was to analyze, in vitro, the magnitude of the volumetric polymerization shrinkage of 7 contemporary composite resins (Definite, Suprafill, SureFil, Filtek Z250, Fill Magic, Alert, and Solitaire) to determine whether there are differences among these materials. The tests were conducted with precision of 0.1 mg. The volumetric shrinkage was measured by hydrostatic weighing before and after polymerization and calculated by known mathematical equations. One-way ANOVA (á=0.05) was used to determine statistically significant differences in volumetric shrinkage among the tested composite resins. Suprafill (1.87±0.01) and Definite (1.89±0.01) shrank significantly less than the other composite resins. SureFil (2.01±0.06), Filtek Z250 (1.99±0.03), and Fill Magic (2.02±0.02) presented intermediate levels of polymerization shrinkage. Alert and Solitaire presented the highest degree of polymerization shrinkage. Knowing the polymerization shrinkage rates of the commercially available composite resins, the dentist would be able to choose between using composite resins with lower polymerization shrinkage rates or adopting technical or operational procedures to minimize the adverse effects deriving from resin contraction during light-activation. PMID:19089177

  8. Polymeric Additives For Graphite/Epoxy Composites

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.; Nir, Z.

    1990-01-01

    Report describes experimental studies of properties of several graphite/epoxy composites containing polymeric additives as flexibilizing or toughening agents. Emphasizes effects of brominated polymeric additives (BPA's) with or without carboxy-terminated butadiene acrylonitrile rubber. Reviews effects of individual and combined additives on fracture toughnesses, environmental stabilities, hot/wet strengths, thermomechanical behaviors, and other mechanical properties of composites.

  9. Radiation polymerization of diethyl fumarate [rapid communication

    NASA Astrophysics Data System (ADS)

    Alkassiri, Haroun

    2005-05-01

    Diethyl fumarate (DEF) has been polymerized by gamma irradiation using doses in the range 50-300 kGy, and in this dose range the polymerization yield increased almost linearly. The polymer has a glass transition temperature of about -20 °C, softening point about 15 °C, and decomposition temperature 300 °C.

  10. Molecular recognition driven catalysis using polymeric nanoreactors.

    PubMed

    Cotanda, Pepa; O'Reilly, Rachel K

    2012-10-25

    The concept of using polymeric micelles to catalyze organic reactions in water is presented and compared to surfactant based micelles in the context of molecular recognition. We report for the first time enzyme-like specific catalysis by tethering the catalyst in the well-defined hydrophobic core of a polymeric micelle.

  11. Spring-loaded polymeric gel actuators

    DOEpatents

    Shahinpoor, Mohsen

    1995-01-01

    Spring-loaded electrically controllable polymeric gel actuators are disclosed. The polymeric gels can be polyvinyl alcohol, polyacrylic acid, or polyacrylamide, and are contained in an electrolytic solvent bath such as water plus acetone. The action of the gel is mechanically biased, allowing the expansive and contractile forces to be optimized for specific applications.

  12. Spring-loaded polymeric gel actuators

    DOEpatents

    Shahinpoor, M.

    1995-02-14

    Spring-loaded electrically controllable polymeric gel actuators are disclosed. The polymeric gels can be polyvinyl alcohol, polyacrylic acid, or polyacrylamide, and are contained in an electrolytic solvent bath such as water plus acetone. The action of the gel is mechanically biased, allowing the expansive and contractile forces to be optimized for specific applications. 5 figs.

  13. Escalation of polymerization in a thermal gradient

    PubMed Central

    Mast, Christof B.; Schink, Severin; Gerland, Ulrich; Braun, Dieter

    2013-01-01

    For the emergence of early life, the formation of biopolymers such as RNA is essential. However, the addition of nucleotide monomers to existing oligonucleotides requires millimolar concentrations. Even in such optimistic settings, no polymerization of RNA longer than about 20 bases could be demonstrated. How then could self-replicating ribozymes appear, for which recent experiments suggest a minimal length of 200 nt? Here, we demonstrate a mechanism to bridge this gap: the escalated polymerization of nucleotides by a spatially confined thermal gradient. The gradient accumulates monomers by thermophoresis and convection while retaining longer polymers exponentially better. Polymerization and accumulation become mutually self-enhancing and result in a hyperexponential escalation of polymer length. We describe this escalation theoretically under the conservative assumption of reversible polymerization. Taking into account the separately measured thermophoretic properties of RNA, we extrapolate the results for primordial RNA polymerization inside a temperature gradient in pores or fissures of rocks. With a dilute, nanomolar concentration of monomers the model predicts that a pore length of 5 cm and a temperature difference of 10 K suffice to polymerize 200-mers of RNA in micromolar concentrations. The probability to generate these long RNAs is raised by a factor of >10600 compared with polymerization in a physical equilibrium. We experimentally validate the theory with the reversible polymerization of DNA blocks in a laser-driven thermal trap. The results confirm that a thermal gradient can significantly enlarge the available sequence space for the emergence of catalytically active polymers. PMID:23630280

  14. Permeability of Rubbery and Glassy Membranes of Ionic Liquid Filled Polymersome Nanoreactors in Water.

    PubMed

    So, Soonyong; Yao, Letitia J; Lodge, Timothy P

    2015-12-01

    Nanoemulsion-like polymer vesicles (polymersomes) having ionic liquid interiors dispersed in water are attractive for nanoreactor applications. In a previous study, we demonstrated that small molecules could pass through rubbery polybutadiene membranes on a time scale of seconds, which is practical for chemical transformations. It is of interest to determine how sensitive the rate of transport is to temperature, particularly for membranes in the vicinity of the glass transition (Tg). In this work, the molecular exchange rate of 1-butylimidazole through glassy polystyrene (PS) bilayer membranes is investigated via pulsed field gradient nuclear magnetic resonance (PFG-NMR) over the temperature range from 25 to 70 °C. The vesicles were prepared by the cosolvent method in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([EMIM][TFSI]), and four different polystyrene-b-poly(ethylene oxide) (PS-PEO) diblock polymers with varying PS molecular weights were examined. The vesicles were transferred from the ionic liquid to water at room temperature to form nanoemulsion solutions of polymer vesicles in water. The exchange rate of 1-butylimidazole added to the aqueous solutions was observed under equilibrium conditions at each temperature. The exchange rate decreased as the membrane thickness increased, and the exchange rate through the glassy membranes was three to four times slower than through the rubbery polybutadiene membranes under the same experimental conditions. These results demonstrate that the permeability through nanosized membranes depends on both the dimension and chemistry of membrane-forming blocks. Furthermore, the exchange rate was investigated as a function of temperature in the vicinity of the Tg of PS-PEO membranes. The exchange rate, however, is not a strong function of the temperature in the vicinity of the membrane Tg, due to a combination of the nanoscopic dimension of the membrane, and some degree of solvent

  15. Permeability of Rubbery and Glassy Membranes of Ionic Liquid Filled Polymersome Nanoreactors in Water.

    PubMed

    So, Soonyong; Yao, Letitia J; Lodge, Timothy P

    2015-12-01

    Nanoemulsion-like polymer vesicles (polymersomes) having ionic liquid interiors dispersed in water are attractive for nanoreactor applications. In a previous study, we demonstrated that small molecules could pass through rubbery polybutadiene membranes on a time scale of seconds, which is practical for chemical transformations. It is of interest to determine how sensitive the rate of transport is to temperature, particularly for membranes in the vicinity of the glass transition (Tg). In this work, the molecular exchange rate of 1-butylimidazole through glassy polystyrene (PS) bilayer membranes is investigated via pulsed field gradient nuclear magnetic resonance (PFG-NMR) over the temperature range from 25 to 70 °C. The vesicles were prepared by the cosolvent method in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([EMIM][TFSI]), and four different polystyrene-b-poly(ethylene oxide) (PS-PEO) diblock polymers with varying PS molecular weights were examined. The vesicles were transferred from the ionic liquid to water at room temperature to form nanoemulsion solutions of polymer vesicles in water. The exchange rate of 1-butylimidazole added to the aqueous solutions was observed under equilibrium conditions at each temperature. The exchange rate decreased as the membrane thickness increased, and the exchange rate through the glassy membranes was three to four times slower than through the rubbery polybutadiene membranes under the same experimental conditions. These results demonstrate that the permeability through nanosized membranes depends on both the dimension and chemistry of membrane-forming blocks. Furthermore, the exchange rate was investigated as a function of temperature in the vicinity of the Tg of PS-PEO membranes. The exchange rate, however, is not a strong function of the temperature in the vicinity of the membrane Tg, due to a combination of the nanoscopic dimension of the membrane, and some degree of solvent

  16. Lithium-Air and ionic Liquids

    SciTech Connect

    Kellar, Michael

    2015-09-01

    The final portion of this project was accomplished at Sandia National Labs, Livermore, with the overall goal being to optimize lithium-air cells with an ionic liquid electrolyte. Both of these are potential future routes for lithium-ion technology. Lithiumair presents the advantage of higher gravimetric energy density, and ionic liquids present the advantage of greater hydrophobicity and much lower volatility, along with a larger window of electrochemical stability. Ionic liquids however have several drawbacks for the battery industry. Currently they are not as cost effective as many organic solvents. Additionally, because of the added viscosity of ionic interactions compared to the typical dipole interactions of a solvent, the ionic conductivity is lower than for common organic solvents.

  17. Supported Ionic Liquid Membranes for Gas Separation

    SciTech Connect

    Myers, C.R.; Ilconich, J.B.; Pennline, H.W.; Luebke, D.R.

    2007-08-01

    Ionic liquids have been rapidly gaining attention for various applications including solvent separation and gas capture. These substances are noted for extremely low vapor pressure and high CO2 solubility making them ideal as transport or capture media for CO2 abatement in power generation applications. Ionic liquids, combined with various supports to form membranes, have been proven selective in CO2 separation. Several ionic liquids and a variety of polymer supports have been studied over a temperature range from 37°C to 300°C and have been optimized for stability. The membranes have demonstrated high permeability and high selectivity since the supported ionic liquid membranes incorporate functionality capable of chemically complexing CO2. A study aimed at improving supported ionic liquid membranes will examine their durability with greater transmembrane pressures and the effects on CO2 permeance, CO2/H2 selectivity and thermal stability.

  18. Kinetic studies and applications of atom transfer radical polymerization

    NASA Astrophysics Data System (ADS)

    Paik, Hyun-Jong

    2001-07-01

    The study of basic kinetic parameters in atom transfer radial polymerization (ATRP) is reported. Novel methods were developed for measuring the activation and deactivation rate constants in ATRP. Using the developed methods, the rate constants for several model systems were determined under various conditions. The obtained data were consistent with the observations in ATRP, and provided further quantitative insight into understanding of the ATRP processes. Two applications of the developed methods are described. Firstly, the participation of free radical intermediates in copper catalyzed atom transfer reactions was investigated using three kinetic methods: racemization, halogen exchange and trapping reactions. The similar rates of these three reactions suggested that the rate-determining step in these three reactions is the generation of the same intermediate, presumably a free radical in the atom transfer process. The second application of the developed methods was comparison of the catalytic activity of several Cu-based tridentate ligands. The systematic evaluation of activities of different ligands elucidated a correlation between atom transfer reactions and ligand structures. The controlled homopolymerizations of methyl acrylate and acrylonitrile are reported. The use of CuBr/substituted 2,2'-bipyridine based catalysts led to the successful controlled ATRP of methyl acrylate. The results of the kinetic study of methyl acrylate were consistent with the proposed mechanism. Also, the successful preparation of well-defined polyacrylonitrile was achieved. However, there were questions about the side reactions resulting in the reduction in the polymerization rate. An interpretation of the abnonnal kinetic behavior was proposed based on extensive end group analysis. Using site transformation techniques, block copolymerizations of two monomers were achieved where one monomer was polymerizable via ATRP and the other monomer was not. Three different examples are

  19. Synergistic Effects Between Phosphonium-Alkylphosphate Ionic Liquids and Zinc Dialkyldithiophosphate (ZDDP) as Lubricant Additives

    DOE PAGES

    Qu, Jun; Barnhill, William C.; Luo, Huimin; Meyer, III, Harry M.; Leonard, Donovan N.; Landauer, Alexander K.; Kheireddin, Bassem; Gao, Hong; Papke, Brian L; Dai, Sheng

    2015-07-14

    Unique synergistic effects between phosphonium-alkylphosphate ionic liquids and zinc dialkyldithiophosphate (ZDDP) are discovered when used together as lubricant additives, resulting in significant friction and wear reduction along with distinct tribofilm composition and mechanical properties. The synergism is attributed to the 30-70× higher-than-nominal concentrations of hypothetical new compounds (via anion exchange between IL and ZDDP) on the fluid surface/interface.

  20. Targeted polymeric nanoparticles for cancer gene therapy

    PubMed Central

    Kim, Jayoung; Wilson, David R.; Zamboni, Camila G.; Green, Jordan J.

    2015-01-01

    In this article, advances in designing polymeric nanoparticles for targeted cancer gene therapy are reviewed. Characterization and evaluation of biomaterials, targeting ligands, and transcriptional elements are each discussed. Advances in biomaterials have driven improvements to nanoparticle stability and tissue targeting, conjugation of ligands to the surface of polymeric nanoparticles enable binding to specific cancer cells, and the design of transcriptional elements has enabled selective DNA expression specific to the cancer cells. Together, these features have improved the performance of polymeric nanoparticles as targeted non-viral gene delivery vectors to treat cancer. As polymeric nanoparticles can be designed to be biodegradable, non-toxic, and to have reduced immunogenicity and tumorigenicity compared to viral platforms, they have significant potential for clinical use. Results of polymeric gene therapy in clinical trials and future directions for the engineering of nanoparticle systems for targeted cancer gene therapy are also presented. PMID:26061296