Takaya Sato

Novel Solid‐State Polymer Electrolyte of Colloidal Crystal Decorated with Ionic‐Liquid Polymer Brush

Much attention has been directed toward polymeric and ionicliquid (IL) electrolytes and their composites for improving the safety in energy devices including lithium-ion rechargeable batteries (LIBs), electric double layer capacitors, and dye-sensitized solar cells. [ 1–4 ] For practical use, however, the most serious problem is that ionic conductivity is greatly spoiled. Here, we show an entirely new concept for fabricating a leakand vapor-free, non-fl ammable, and solid electrolyte with a highly ion-conductive network channel. This was fi rst achieved by three-dimensional, regular self-assembly in a crystal of hybrid silica particles (PSiPs) with an IL-type of concentrated polymer brushes (CPBs) in the presence of a small amount of IL, hence providing a polymer-brush domain that is continuously connected as a network channel and enhances the ion conduction by coupling with the segmental motion. This is completely different from the previously reported electrolyte reinforced with nanoparticles, which are in an amorphous state but not in a crystal. The strategy is based on our recent achievements involving the CPB and IL. First, by surface-initiated living radical polymerization (surface-initiated LRP), we succeeded in exceptionally densely grafting well-defi ned polymers on a solid surface to produce a well-defi ned CPB and found that it showed properties including high modulus, super lubrication, and unique size exclusion that were quite different and even unpredictable from those of the previously studied semidilute polymer brushes (SDPBs). [ 5 ] Second, we demonstrated that a solvent suspension, which is liquid but not solid, of monodisperse silica particles (SiP) with the CPB of poly(methyl methacrylate) (PMMA) formed a new type (semisoft type) of colloidal crystal; [ 6 ] unlike the previously known (soft and hard) colloidal crystals, the driving

High energy-density capacitor based on ammonium salt type ionic liquids and their mixing effect by propylene carbonate

Novel ionic liquids comprised of a quaternary ammonium salt type cation have been applied to an electrolyte for high-performance electric double-layer capacitors (EDLCs). The novel ionic liquids [IL-B; N, N-diethyl-N-methyl(2-methoxyethyl)ammonium tetrafluoroborate (DEME-BF 4 ) and IL-T; N, N-diethyl-N-methyl(2-methoxyethyl)ammonium bis(trifluoromethylsulfonyl)imide (DEME-TFSI)] are promising candidates for EDLC electrolytes in terms of high decomposition voltage (wide voltage window), nonflammability, easy handling, nonvolatility, and low production costs. Notably, the wide voltage window indicates that IL-B and IL-T are more advantageous in energy density than typical propylene carbonate-based electrolytes (i.e., TEA-BF 4 /PC) and a conventional imidazolium type ionic liquid (i.e., 1-ethyl-3-methylimidazolium tetrafluoroborate, EMI-BF 4 ). The effectiveness of IL-B and IL-T on the application to EDLC electrolytes has been confirmed by using KOH-activated mesophase pitch-based carbon fibers (MPCFs) as an electrode material. The combination of IL-T (IL-B) and KOH-activated MPCFs has provided 56 F/g (51 F/g) of high specific capacitance at maximum (1 mA/cm 2 discharge current density, 3.5 V charging voltage), which is equivalent to 224 F/g (204 F/g) in a conventional three-compartment measuring system. In addition, the specific capacitance of both ionic liquids has increased proportional to the increase in the applied voltage from 2.5 to 3.5 V, in contrast to the decline observed for TEA-BF 4 /PC at 3.5 V. Furthermore, the mixture of the IL-B exhibiting high viscosity with propylene carbonate (1 M of IL-B in PC) has been found to provide an excellent capacitance behavior comparable to that observed for the pure IL-B. This indicates that the mixture has great potential for application to EDLC electrolytes, similar to pure IL-B and IL-T.

Serum metabolomic profile and potential biomarkers for severity of fibrosis in nonalcoholic fatty liver disease

BackgroundBiomarker for usefulness in diagnosing advanced fibrosis in nonalcoholic fatty liver disease (NAFLD) is expected. In order to discover novel biomarkers for NAFLD and its pathogenesis, we performed matabolomics screening.Methods(1) The initial cohort was 44 NAFLD patients. (2) This validation cohort was 105 NAFLD patients, 26 primary biliary cirrhosis (PBC) patients, and 48 healthy controls. Using capillary electrophoresis and liquid chromatography with mass spectrometry, we analyzed low molecular weight metabolites in these groups.Results1. In the initial cohort, we found 28 metabolites associated with advanced fibrosis. Among them, 4 sulfated steroids showed the greatest difference. A decrease of dehydroepiandrosterone sulfate (DHEA-S) and 5α-androstan-3β ol-17-one sulfate (etiocholanolone-S) was observed with the progression of fibrosis. Furthermore, 16 hydroxydehydroepiandrosterone sulfate (16-OH-DHEA-S) increased with the progression of fibrosis. 2. In the validation cohort, the decrease of DHEA-S and etiocholanolone-S, as well as the increase of 16-OH-DHEA-S, with the progression of fibrosis was confirmed. The 16-OH-DHEA-S/DHEA-S ratio and 16-OH-DHEA-S/etiocholanolone-S ratio were even more strongly associated with the grade of fibrosis. Among PBC patients, 16-OH-DHEA-S tended to be higher in stages 3 and 4 than in stages 1 and 2. However, levels of DHEA-S, etiocholanolone-S, and the two ratios were not associated with the stage of PBC.ConclusionSeveral metabolic products were found to be biomarkers of fibrosis in NAFLD and could also be useful for diagnosis of this condition. Our findings suggested disturbance of hormone metabolism in NAFLD and might lead to the development of new therapy.

Lubrication mechanism of concentrated polymer brushes in solvents: effect of solvent viscosity

We investigated the frictional properties of concentrated polymer brushes (CPBs) of poly(methyl methacrylate) (PMMA) immersed in two highly viscous ionic liquids (ILs) that are good solvents for PMMA: N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide (DEME-TFSI) and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMI-TFSI). These ILs could swell the CPB of PMMA to the same degree as toluene, a more commonly used good solvent of much lower viscosity. The CPB of PMMA effectively reduced the interaction between surfaces in these ILs and hence developed otherwise hidden hydrodynamic lubrication, which was characterized by the dependence of the frictional coefficient μ on shear velocity v. In the hydrodynamic-lubrication regime, the linear relationship was obtained between them in the double logarithmic plot, giving a slope close to unity, which is expected for a Newtonian fluid, in the solvents studied even though the viscosity differed by nearly two orders of magnitude. More interestingly, the μ values in this regime of lubrication were found to be scaled by the viscosity of the solvent. These results not only enable us to discuss the details of the effect of solvent viscosity on lubrication properties of the CPB systems but also demonstrated their ability to act as an excellent lubrication system in combination with ILs as lubricating fluids.

Adenomyoma of the common hepatic duct

A very rare case of adenomyoma of the common hepatic duct is described. A 54-year-old woman was admitted with impending obstructive jaundice secondary to adenomyoma of the common hepatic duct. Our impression, formulated from her clinical presentation, endoscopic investigations, and biochemical and radiological findings, was a cancer of the proximal common hepatic duct. The patient was treated successfully by combination surgical resection and hepaticojejunostomy. Despite our obtaining an intraoperative frozen section, final histological examination was required to confirm the diagnosis. The patient remains well 16 months postoperatively. A survey of the world literature revealed that this is the second report of adenomyoma occurring in the common hepatic duct.

Controlled polymerization of protic ionic liquid monomer by ARGET-ATRP and TERP.

The direct synthesis of structurally well-defined protic polymeric ionic liquid (PIL) with controlled molecular weight and molecular weight distribution is examined using N,N-diethyl-N-(2-methacryloylethyl) ammonium bis(tri-fluoromethylsulfonyl)imide (DEMH-TFSI) as a monomer. Three polymerization methods, namely, atom transfer radical polymerization (ATRP), activators regenerated by electron transfer (ARGET)-ATRP, and organotellurium-mediated living radical polymerization (TERP) are employed in this study. While the polymerization by ATRP is slow and does not reach high monomer conversion that under ARGET-ATRP and TERP proceeds smoothly and affords structurally well-defined poly(DEMH-TFSI)s. TERP is especially efficient for the control and poly(DEMH-TFSI)s with low to high molecular weights (M¯(n) = 49 100-392 500) and narrow molecular weight distributions (M¯(w)/M¯(n) = 1.17-1.46) are obtained. These results represent the first example of synthesis of a structurally well-defined protic, ammonium PIL by direct polymerization of the protic ionic liquid monomer. The polymerization of N,N-diethyl-N-(2-methacryloylethyl)-N-methylammonium bis(trifluoromethylsulfonyl)imide (DEMM-TFSI), which possesses a quaternary ammonium salt, also proceeds in a highly controlled manner under TERP conditions. A diblock copolymer, polystyrene-block-poly(DEMH-TFSI), is also successfully synthesized by TERP.

Highly Conductive Plastic Crystals Based on Fluorohydrogenate Anions

The new ionic plastic crystals N,N-dimethylpyrrolidinium fluorohydrogenate [DMPyr(FH)(2)F] and N-ethyl-N-methylpyrrolidinium fluorohydrogenate [EMPyr(FH)(2)F] were prepared, and their physicochemical, structural, and electrochemical properties were investigated. The DMPyr(FH)(2)F and EMPyr(FH)(2)F salts exhibited small entropy changes of melting, 4.1 and 2.0 J K(-1) mol(-1), respectively, and had ionic plastic crystal phases in the temperature ranges of 258-325 and 236-303 K, respectively. These phases had NaCl-type structures; the lattice constants were 9.90 Å for DMPyr(FH)(2)F and 10.18 Å for EMPyr(FH)(2)F. The ionic conductivities of the ionic plastic crystal phases ranged from 10(0) to 10(1) mS cm(-1) [e.g., 10.3 mS cm(-1) at 298 K for DMPyr(FH)(2)F and 14.4 mS cm(-1) at 288 K for EMPyr(FH)(2)F]. Pulsed-field gradient spin-echo NMR spectroscopy revealed that only the anion could move in the ionic plastic crystal phase as a charge carrier with a diffusion coefficient of ~10(-7) cm(2) s(-1). The self-diffusion coefficient of the cation in the ionic plastic crystal phase of DMPyr(FH)(2)F was too small to measure, although the cation in EMPyr(FH)(2)F had a slight mobility below 303 K.

Synthesis of Monodisperse Silica Particles Grafted with Concentrated Ionic Liquid-Type Polymer Brushes by Surface-Initiated Atom Transfer Radical Polymerization for Use as a Solid State Polymer Electrolyte

A polymerizable ionic liquid, N,N-diethyl-N-(2-methacryloylethyl)-N-methylammonium bis(trifluoromethylsulfonyl)imide (DEMM-TFSI), was polymerized via copper-mediated atom transfer radical polymerization (ATRP). The polymerization proceeded in a living manner producing well-defined poly(DEMM-TFSI) of target molecular weight up to about 400 K (including a polycation and an counter anion). The accurate molecular weight as determined by a GPC analysis combined with a light scattering measurement, and the molecular weight values obtained exhibited good agreement with the theoretical values calculated from the initial molar ratio of DEMM-TFSI and the monomer conversion. Surface-initiated ATRP on the surface of monodisperse silica particles (SiPs) with various diameters was successfully performed, producing SiPs grafted with well-defined poly(DEMM-TFSI) with a graft density as high as 0.15 chains/nm2. Since the composite film made from the silica-particle-decorated polymer brush and ionic liquid shows a relatively high ionic conductivity, we have evaluated the relationship between the grafted brush chain length and the ionic conductivity.

Lubrication Properties of Ammonium-Based Ionic Liquids Confined between Silica Surfaces Using Resonance Shear Measurements

To evaluate the friction properties of new lubrication systems, two types of ammonium-based ionic liquids (ILs), N,N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium tetrafluoroborate ([DEME][BF4]) and N,N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium bis(trifluoromethanesulfonyl) imide ([DEME][TFSI]), were investigated by resonance shear measurements (RSM) and reciprocating type tribotests between silica (glass) surfaces. RSM revealed that an IL layer of ca. 2 nm in thickness was maintained between the silica surfaces under an applied load of 0.40 mN ∼ 1.2 mN. The relative intensity of the RMS signal indicated that the friction of the system was lower for [DEME][BF4], 0.12, than that of [DEME][TFSI], 0.18. On the other hand, the friction coefficients μk obtained from the tribotests of [DEME][BF4] were lower than that of [DEME][TFSI] for sliding velocities in the range of 5.0 × 10(-4) m s(-1) to 3.0 × 10(-2) m s(-1) under applied loads of 196-980 mN. The friction coefficients obtained by the tribotest are discussed with reference to the RSM results.

Energy transfer between J-aggregates of quinocyanine dyes in the sodium alginate films

Abstract New optical materials such as the J-aggregate of quinocyanine dyes in polymer films were fabricated and studied. 1,1′-diethyl-2,2′-cyanine chloride and iodide (dye, I, X = Cl or I); as well as 5,6,5′,6′-dibenzo-1,1′-diethyl-2,2′-cyanine chloride (dye II) in the sodium alginate (SA) films easily formed the J-aggregate, characterized by a sharp absorption of the J-band and the resonance fluorescence. The evidence of long distance energy transfer between extended donor and extended acceptor J-aggregates was presented. The critical distance of the energy transfer of about 55 A was estimated on the base of spectral and fluorescence lifetime measurements.