The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Millicent A Firestone - One of the best experts on this subject based on the ideXlab platform.
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patterning a π conjugated polyelectrolyte through sequential polymerization of a bifunctional ionic Liquid Monomer
Polymer, 2014Co-Authors: Scott M Brombosz, Sonke Seifert, Millicent A FirestoneAbstract:Abstract An electronically conductive polyelectrolyte is prepared by the sequential polymerization of a bifunctional imidazolium-based ionic Liquid (IL) Monomer, composed of a thienyl and vinyl containing cation paired with a tetrafluoroborate anion. In the first step, potentiodynamic electropolymerization of the thienyl moiety forms a cationic polyalkylthiophene that is soluble in select organic solvents. Cyclic voltammetry (CV) was used to determine the polymer p-doping potential (0.31 V) and the bipolaronic state (1.49 V). The polymer exhibits electrochromism, converting from red in the neutral state (λmax = 443 nm) to dark blue in the polaronic state (λmax = 819 nm). The solution-processable polymer can be cast into a film, masked and patterned by UV-initiated free radical polymerization of the vinyl moiety. Small-angle X-ray scattering (SAXS) revealed that the insoluble crosslinked polyalkylthiophene–polyvinylimidazolium adopts a lamellar structure with a lattice spacing of 3.3 nm. Four-probe d.c. conductivity measurements determined the de-doped electrical conductivity was 1.0 × 10−2 S/cm. The results underscore the importance of the anion in controlling the polymerization of IL Monomers.
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electropolymerization of a bifunctional ionic Liquid Monomer yields an electroactive Liquid crystalline polymer
Advanced Functional Materials, 2010Co-Authors: Gregory A Becht, Christopher T Burns, Millicent A FirestoneAbstract:The preparation and polymerization of a bifunctional imidazolium-based ionic Liquid (IL) Monomer that incorporates both a vinyl group and a thiophene moiety is reported. Potentiodynamic electropolymerization of the Monomer produces an optically birefringent polymer film that strongly adheres to the electrode surface. Fourier transform IR spectroscopy shows that polymerization occurs through both the vinyl and thienyl groups. Cylic voltammetry (CV) is used to determine the polymer oxidation potential (1.66 V) and electrochemical bandgap, Eg, of 2.45 eV. The polymer exhibits electrochromism, converting from yellow in the neutral form ({lambda}{sub max} = 380 nm) to blue in the polaronic state at 0.6 V ({lambda}{sub max} = 672 nm) and to blue-grey in the bipolaronic state at 1.2 V ({lambda}{sub max} > 800 nm). Topographic atomic force microscopy (AFM) images reveal isolated (separated) fibrils. Grazing-incidence small-angle X-ray scattering (GISAXS) studies indicate a lamellar structure with a lattice spacing of 3.2 nm. Wide-angle X-ray diffraction (WAXD) studies further suggest that the polymerized thiophene sheets are oriented perpendicular to the polymerized vinylimidazolium. The electrical conductivity, as determined by four-probe dc conductivity measurements was found to be 0.53 S cm{sup -1} in the neutral form and 2.36 S cm{sup -1} in the iodine-doped state, valuesmore » higher than typically observed for polyalkylthiophenes. The structural ordering is believed to contribute to the observed enhancement of the electrical conductivity.« less
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cytoskeleton mimetic reinforcement of a self assembled n n dialkylimidazolium ionic Liquid Monomer by copolymerization
Macromolecules, 2009Co-Authors: Simonida Grubjesic, Sonke Seifert, Millicent A FirestoneAbstract:Preparation and photopolymerization of a decylmethylimidazolium ionic Liquid (IL) that possesses an acrylate counteranion are described. This IL Monomer self-assembles upon addition of water and can be copolymerized with poly(ethylene glycol) diacrylate (PEGDA) in the presence of a photoinitiator, forming a mechanically durable material that adopts a lamellar structure with in-plane hexagonally ordered pores, as evidenced by small-angle X-ray scattering (SAXS). Thermogravimetric analysis, the extent of polymerization, and solubility−swelling studies indicate the formation of a network copolymer of the IL Monomer and the PEGDA. Additional evidence for the formation of a nanostructured copolymer is provided by evaluating the product formed by replacement of the IL Monomer with the nonpolymerizable analogue, decylmethylimidazolium chloride. The results demonstrate the possibility of designing a self-assembled amiphiphilic bilayer architecture that is reinforced by polymerization and cross-linking.
C. Sun - One of the best experts on this subject based on the ideXlab platform.
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Micro-stereolithography of polymeric and ceramic microstructures
Sensors and Actuators A: Physical, 1999Co-Authors: Xueyi Zhang, X. N. Jiang, C. SunAbstract:Micro-stereolithography (μSL) is a novel micro-manufacturing process which builds the truly 3D microstructures by solidifying the Liquid Monomer in a layer by layer fashion. In this work, an advanced μSL apparatus is designed and developed which includes an Ar+laser, the beam delivery system, computer-controlled precision x-y-z stages and CAD design tool, and in situ process monitoring systems. The 1.2 μm resolution of μSL fabrication has been achieved with this apparatus. The microtubes with high aspect ratio of 16 and real 3D microchannels and microcones are fabricated on silicon substrate. For the first time, μSL of ceramic microgears has been successfully demonstrated.
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Micro-stereolithography for MEMS
Proceedings of Microelectromechanical Systems (MEMS), 1998Co-Authors: Xiaofeng Zhang, X. N. Jiang, C. SunAbstract:Micro stereolithography (SL) is a novel micromanufacturing process which builds truly 3D microstructures by solidifying the Liquid Monomer in a layer by layer fashion. In this work, an advanced micro stereolithography (SL) apparatus is designed and developed which includes an Ar+ laser, the beam delivery system, computer-controlled precision x-y-z stages and CAD design tool, and in situ process monitoring systems. The 1.2 m resolution of SL fabrication has been achieved with this apparatus. Micro tubes with high aspect ratio of 16 and real 3D microchannels and micro cones are fabricated on silicon substrates. For the first time, micro stereolithography of ceramic micro gears has been successfully demonstrated
Gordon L Graff - One of the best experts on this subject based on the ideXlab platform.
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ultrahigh rate wide area plasma polymerized films from high molecular weight low vapor pressure Liquid or solid Monomer precursors
Journal of Vacuum Science and Technology, 1999Co-Authors: John D Affinito, Mark E Gross, Phillip A Mounier, Gordon L GraffAbstract:A new process has been developed for the high rate vacuum deposition of solid films from high molecular weight/low vapor pressure Liquid, or even solid, Monomer precursors. The gas resulting from the flash evaporation of a Liquid Monomer mixture or from a suspension of Liquid Monomer and insoluble solid particles is used as the support medium for a glow discharge in a plasma enhanced chemical vapor deposition-like process. Due to the high molecular weight/low vapor pressure nature of the precursors, the plasma of the flash evaporated gas cryocondenses at an extremely high rate on substrates at ambient, and higher, temperatures. Upon condensation the liquefied plasma immediately begins to polymerize to form a solid film due to the high concentration of radicals and ions contained in the Liquid film. The process has been successfully implemented in a vacuum roll coating system in a roll-to-roll deposition process. Polymer films and molecularly doped polymer composite films of polymer and light emitting orga...
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Ultrahigh rate, wide area, plasma polymerized films from high molecular weight/low vapor pressure Liquid or solid Monomer precursors
Journal of Vacuum Science and Technology, 1999Co-Authors: John D Affinito, Mark E Gross, Phillip A Mounier, Gordon L GraffAbstract:A new process has been developed for the high rate vacuum deposition of solid films from high molecular weight/low vapor pressure Liquid, or even solid, Monomer precursors. The gas resulting from the flash evaporation of a Liquid Monomer mixture or from a suspension of Liquid Monomer and insoluble solid particles is used as the support medium for a glow discharge in a plasma enhanced chemical vapor deposition-like process. Due to the high molecular weight/low vapor pressure nature of the precursors, the plasma of the flash evaporated gas cryocondenses at an extremely high rate on substrates at ambient, and higher, temperatures. Upon condensation the liquefied plasma immediately begins to polymerize to form a solid film due to the high concentration of radicals and ions contained in the Liquid film. The process has been successfully implemented in a vacuum roll coating system in a roll-to-roll deposition process. Polymer films and molecularly doped polymer composite films of polymer and light emitting orga...
Sonke Seifert - One of the best experts on this subject based on the ideXlab platform.
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3d volumetric structural hierarchy induced by colloidal polymerization of a quantum dot ionic Liquid Monomer conjugate
Macromolecules, 2020Co-Authors: Paul M Welch, Sonke Seifert, Timothy A Dreier, Harsha D Magurudeniya, Matthew G Frith, Jan Ilavsky, Aunik K Rahman, Anis Rahman, Amita Joshi Singh, Bryan RingstrandAbstract:Hierarchically structured emissive quantum dot (CdS/CdSe) poly(ionic Liquid) composites are synthesized through colloidal polymerization within a lyotropic Liquid crystal, yielding a solvent-respon...
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patterning a π conjugated polyelectrolyte through sequential polymerization of a bifunctional ionic Liquid Monomer
Polymer, 2014Co-Authors: Scott M Brombosz, Sonke Seifert, Millicent A FirestoneAbstract:Abstract An electronically conductive polyelectrolyte is prepared by the sequential polymerization of a bifunctional imidazolium-based ionic Liquid (IL) Monomer, composed of a thienyl and vinyl containing cation paired with a tetrafluoroborate anion. In the first step, potentiodynamic electropolymerization of the thienyl moiety forms a cationic polyalkylthiophene that is soluble in select organic solvents. Cyclic voltammetry (CV) was used to determine the polymer p-doping potential (0.31 V) and the bipolaronic state (1.49 V). The polymer exhibits electrochromism, converting from red in the neutral state (λmax = 443 nm) to dark blue in the polaronic state (λmax = 819 nm). The solution-processable polymer can be cast into a film, masked and patterned by UV-initiated free radical polymerization of the vinyl moiety. Small-angle X-ray scattering (SAXS) revealed that the insoluble crosslinked polyalkylthiophene–polyvinylimidazolium adopts a lamellar structure with a lattice spacing of 3.3 nm. Four-probe d.c. conductivity measurements determined the de-doped electrical conductivity was 1.0 × 10−2 S/cm. The results underscore the importance of the anion in controlling the polymerization of IL Monomers.
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cytoskeleton mimetic reinforcement of a self assembled n n dialkylimidazolium ionic Liquid Monomer by copolymerization
Macromolecules, 2009Co-Authors: Simonida Grubjesic, Sonke Seifert, Millicent A FirestoneAbstract:Preparation and photopolymerization of a decylmethylimidazolium ionic Liquid (IL) that possesses an acrylate counteranion are described. This IL Monomer self-assembles upon addition of water and can be copolymerized with poly(ethylene glycol) diacrylate (PEGDA) in the presence of a photoinitiator, forming a mechanically durable material that adopts a lamellar structure with in-plane hexagonally ordered pores, as evidenced by small-angle X-ray scattering (SAXS). Thermogravimetric analysis, the extent of polymerization, and solubility−swelling studies indicate the formation of a network copolymer of the IL Monomer and the PEGDA. Additional evidence for the formation of a nanostructured copolymer is provided by evaluating the product formed by replacement of the IL Monomer with the nonpolymerizable analogue, decylmethylimidazolium chloride. The results demonstrate the possibility of designing a self-assembled amiphiphilic bilayer architecture that is reinforced by polymerization and cross-linking.
Jerome Baudoux - One of the best experts on this subject based on the ideXlab platform.
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new epoxy thermosets derived from bisimidazolium ionic Liquid Monomer an experimental and modelling investigation
ACS Sustainable Chemistry & Engineering, 2020Co-Authors: Alexei V Radchenko, Houssem Chabane, Baris Demir, Debra J Searles, Jannick Duchetrumeau, Jeanfrancois Gerard, Jerome Baudoux, Sebastien LiviAbstract:In this study, a novel polymerizable ionic Liquid Monomer (ILM) based on a bis-imidazolium salt was firstly synthesized in order to substitute bisphenol A diglycidyl ether (DGEBA) as starting mater...
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from ionic Liquid epoxy Monomer to tunable epoxy amine network reaction mechanism and final properties
ACS Sustainable Chemistry & Engineering, 2019Co-Authors: Sebastien Livi, Jannick Duchetrumeau, Jeanfrancois Gerard, Charline Chardin, Luanda C Lins, Nour Halawani, Sebastien Pruvost, Jerome BaudouxAbstract:In this work, new (multi)functional-dedicated polymer materials were designed and processed from the copolymerization between novel imidazolium ionic Liquid Monomer (ILM) with a conventional polyetheramine denoted Jeffamine D230. First, a facile and robust synthetic route was investigated in order to design polyfunctional imidazolium Monomers bearing an aromatic ring and two epoxy functions at the end of aliphatic chains. Then, the main mechanisms of epoxy opening leading to polymerization with different kinetics were modeled through the reaction between a monofunctional epoxy and aliphatic mono- and diamines by using “in situ” NMR spectroscopy. Finally, the Monomer molecular structure-network architecture-physical properties relationships of the resulting IL-modified epoxy networks were investigated. As a consequence, epoxy networks with a glass transition temperature of 55 °C and with enhanced properties such as thermal stability (>300 °C), storage modulus of 700 MPa at room temperature, and an ionic co...