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971.
Ute Löffelmann Nan Wang Dario Mager Patrick J. Smith Jan G. Korvink 《Journal of Polymer Science.Polymer Physics》2012,50(1):38-46
A new and solvent‐free process for the fabrication of inkjet printed ionic liquid‐polymer gel microstructures with high‐resolution (line widths of ~40 μm), good electrical conductivity (5–30 mS cm?1), optical transparency, and mechanical flexibility is presented. Carrying out the printing and polymerization process in nitrogen atmosphere eliminates the inhibiting influence of oxygen and guarantees homogeneously gelled structures. Careful selection and combination of ionic liquids (ILs) and unsaturated monomers makes it possible to achieve low viscosities which are printable with commercially available inkjet printers and printheads without adding extra solvents. By using different types and amounts of ILs and monomers the resulting properties of the printed IL‐polymer gels can be controlled in terms of ionic conductivity, optical transmission, and mechanical flexibility. Higher conductivities are possible by using a bifunctional instead of a monofunctional monomer, which allows one to lower the amount of monomer without loss in mechanical strength. Cast samples make it possible to obtain data of transmission (~90% for 170‐μm thick films) and mechanical flexibility (E = 0.02–0.23 MPa) of bulk material. Comparing electrical conductivity of printed and cast samples, the higher values of printed samples indicate the conductivity enhancing influence of moisture absorbed from the surrounding atmosphere after the fabrication process. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011 相似文献
972.
The reaction of o-, m-, and p-F2CCFC6H4X with SF5Br produces an intermediate adduct, F5SCF2CFBrC6H4X, which, on treatment with AgBF4, affords the first useful, high yield preparation of o-, m-, and p-F5SCF2CF2C6H4X. 相似文献
973.
974.
Smith RA Verlet JR Boleat ED Stavros VG Fielding HH 《Faraday discussions》2000,(115):63-70; discussion 79-102
Rydberg electron wavepackets have been studied in molecular NO for a variety of rotational states of the ion core. Predominantly radial motion of the electron wavepacket is observed which is similar to that previously reported in atomic systems. Interference effects similar to those observed in unperturbed Rydberg series are evident and third and fourth order partial revivals are identified. Most interestingly, when the classical period of electronic motion is close to the classical period of rotation of the molecular ion, the molecular dynamics dominates the electronic dynamics. 相似文献
975.
A new method has been developed for the determination of the isotope abundance ratios of deuterium, D, and oxygen-18, 18O, in water vapor (and water) using selected ion flow tube mass spectrometry (SIFT-MS). H3O+ ions are injected into the helium carrier gas where they associate with the H2O and HDO molecules in a sample of water introduced into the carrier gas. The D and 18O contents of the product cluster ions H8DO4+ and H9(18)OO3+ at m/e = 74 and 75, respectively, are determined by reference to the majority cluster ion H9O4+ at m/e = 73. Allowance is made for the contribution of the H8(17)OO3+ ions to the m/z = 74 ions. Absolute isotopic ratios are measured within seconds without the need for precalibration of the SIFT-MS instrument, currently to an accuracy of better than 2%. 相似文献
976.
Step-scan FTIR time-resolved spectroscopy (S2FTIR TRS) in acetonitrile-d3 has been used to probe the acceptor ligand in metal-to-ligand charge transfer (MLCT) excited states of amide-substituted polypyridyl complexes of RuII and in analogues appended to polystyrene. On the basis of ground-to-excited state shifts in v(C = O) of -31 cm-1 for the amide group in [RuII(bpy)2(bpyCONHEt')]2+ (bpyCONHEt' = 4'-methyl-2,2'-bipyridine-4-carboxamide-Et'; Et' = -CH2CH2BzCH2CH3) (1) and in the derivatized polystyrene abbreviated [PS-[CH2-CH2NHCObpy-RuII(bpy)2]20]40+ (3), the excited-state dipole is directed toward the amide-containing pyridyl group in the polymer side chain. Smaller shifts in v(C = O) of -17 cm-1 in [RuII(4,4'-(CONEt2)2bpy)2-(bpyCONHEt')]2+ (2) and in the derivatized polystyrene abbreviated [PS-[CH2CH2NHCObpy-RuII(4,4'-(CONEt2)2bpy)2]20]40+ (4) indicate that the excited-state dipole is directed toward one of the diamide bpy ligands. The nearly identical results for 1 and 3 and for 2 and 4 show that the molecular and electronic structures of the monomer excited states are largely retained in the polymer samples. These conclusions about dipole orientation in the polymers are potentially of importance in understanding intrastrand energy transfer dynamics. The excited-state dipole in 3 is oriented in the direction of the covalent link to the polymer backbone, and toward nearest neighbors. In 4, it is oriented away from the backbone. 相似文献
977.
Ying‐Hung So Donald L. Schmidt Matt T. Bishop Daniel R. Miller Patrick B. Smith Michael J. Radler Mindy Magyar Britton L. Kaliszewski 《Journal of polymer science. Part A, Polymer chemistry》2000,38(8):1283-1290
Upon photolysis or heating, aryl cyclic sulfonium (ACS) zwitterions polymerize by ring‐opening and loss of charge to yield nonionic polymers. These water‐soluble monomers potentially are useful for photolithography because they can be cast from and developed in water. The ACS zwitterion from bisphenol A, 1,1′‐[isopropylidenebis(6‐hydroxy‐3,1‐phenylene)] bis (tetrahydrothiophenium hydroxide) bis(inner salt) (1) is a negative‐tone, photosensitive material that after photolysis yields a crosslinked film. Unexposed regions are removed by water. The cured film has a low dielectric constant, high volume resistivity, a high degree of planarization, low residual stress, thermogravimetric stability, acceptable fracture toughness, and high hardness. These are desirable properties for a dielectric material used in microelectronic applications. However, a shortcoming of the material is its low Tg, at about 140 °C. A second ACS zwitterion, 1,1′‐[fluorenylidenebis(6‐hydroxy‐3,1‐phenylene)] bis(tetrahydrothiophenium hydroxide) bis(inner salt) (2) was prepared that yields a crosslinked polymer with a higher Tg of about 190 °C. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1283–1290, 2000 相似文献
978.
Smith MD Stepan AF Ramarao C Brennan PE Ley SV 《Chemical communications (Cambridge, England)》2003,(21):2652-2653
Palladium-containing perovskites (LaFe0.57Co0.38Pd0.05O3) have been exploited as recoverable and reuseable catalysts in Suzuki coupling reactions; residual levels of Pd after removal of the catalyst by filtration are low (2 ppm) despite evidence that the reaction is occurring via a homogeneous process. 相似文献
979.
Davies SG Díez D El Hammouni MM Garner AC Garrido NM Long MJ Morrison RM Smith AD Sweet MJ Withey JM 《Chemical communications (Cambridge, England)》2003,(19):2410-2411
Comparison of the kinetic and parallel kinetic resolutions of methyl (RS)-5-tert-butyl-cyclopentene-1-carboxylate allows for the efficient synthesis of both (1R,2S,5S)- and (1S,2R,5R)-enantiomers of methyl 2-amino-5-tert-butyl-cyclopentane-1-carboxylate. 相似文献
980.
The novel complex (eta 6-benzylamine)tricarbonylchromium(0) 11 was prepared in up to 66% yield by direct complexation with Cr(CO)6 in refluxing 1,4-dioxane. Imine derivatives of this complex were readily deprotonated at the benzylic position by diamide 5, and the resultant anions reacted regioselectively with electrophiles (Me3SiCl or MeI) to give fairly good yields of products substituted at the benzylic carbon. Products of up to 87% e.e. were obtained in these reactions, with the highest enantioselectivity being derived from the tert-butyl-substituted imine complex 25. 相似文献