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Marine mussels contain an abundant catechol moiety, 3,4‐dihydroxyphenylalanine (DOPA), in their interfacial foot proteins. DOPA contributes to both surface adhesion and bridging between the surface and overhead proteins (surface priming) by taking advantage of the unique redox properties of catechol. Inspired by the mussel surface priming mechanism, herein we synthesized a series of DOPA‐mimetic analogs – a bifunctional group molecule, consisting of a catechol group and an acrylic group at the opposite ends. The surface primers with differently substituted (−COOH, −CH3) alkyl chains in the middle spacer were synthesized. Time‐dependent oxidation and redox potentials of the surface primers were studied in an oxidizing environment to gain a better understanding of the mussel‘s redox chemistry. The thickness and degree of priming of the surface primers on silicon‐based substrates were analyzed by ellipsometry and UV/Vis absorption spectroscopy. The post‐reactivity of the acrylic groups of the primed layer was first visualized through a reaction with an acrylic group‐reactive dye., Mussel‐inspired DOPA‐mimetic surface primers (SPs) with differently substituted (−CH3/−COOH) alkyl chains in the middle spacer were synthesized, characterized, and their priming efficiencies were investigated. The co‐deposition of primary amine‐containing catechol molecules improved the priming capability of the surface primers. The oxidative mechanism and molecular principles of SPs self‐assembly adherence to glass substrate have been revealed.

Paracetamol (PC), a pharmaceutical widely used in medical fields, is often discharged into water, causing harm to human health. Thus, it is imperative to develop photocatalysts which can efficiently remove PC from the wastewater. Graphitic carbon nitride (GCN) constitutes an important class of photocatalysts in the area of energy and environmental pollution control. Herein, we present a cobalt doped GCN (Co/GCN) to enhance the photodegradation of PC in the wastewater. Co/GCN significantly improved the separation of electrons and holes, narrowed band gap energy, and broadened the absorption of light. Even at high PC initial concentration, the Co/GCN exhibited a PC removal efficiency of 82.6% upon exposure to sunlight for 60 min, which is 1.7 time higher than that of undoped GCN. At low initial concentration of ≤1 mg/L, the Co/GCN was capable of decomposing PC with highest degradation efficiency reaching almost 100%. The kinetic result showed that the Co/GCN achieved the photodegradation rate 3.7 times higher than that of GCN. Furthermore, the Co/GCN can be recycled multiple times, indicating its potential use as photocatalyst for the treatment of pharmaceutical in wastewater.

Microplastics are distributed in oceans worldwide, and the negative effects of microplastics on the environment and human health are increasing. Generally, three methods are employed to remove microplastics: filtration, biological degradation, and coagulation. Of these methods, filtration is the most commonly used but depends on the filter size or degree of microplastic coagulation. Although Fe- or Al-salts are generally used for coagulation via electrostatic interactions between metal ion and microplastics, their microplastic removal efficiency is less than 40%, and the smaller the size of microplastics, the lower is the removal efficiency. In order to improve the removal efficiency, metal–phenolic coordinate bonds were newly utilized for microplastic coagulation. Plant-derived tannic acid contributed to interfacial bridging between the microplastics and Fe3+. Using 0.5 μm polystyrene beads as model microplastics, a removal efficiency of more than 90% within 5 min was achieved. Since microplastics mostly accumulate in the gut of animals, rat intestine IEC18 cells exposed to purified water from the microbead suspension were risk assessed, revealing that water purified using the coagulation-based method reduced oxidative stress and inflammatory cytokines to levels similar to those in cells exposed to water without microbeads.

Realizing Li-metal batteries requires overcoming several hurdles, such as volume changes, a thickening solid electrolyte interphase, and safety issues associated with uncontrollable Li growth. Introducing a 3D conductive framework that improves Li reversibility by decreasing the local current density and alleviating volume changes can mitigate these issues, but inevitable Li growth on the top surface remains problematic. To address this, herein, we report an electrical conductivity-controlled 3D host consisting of a glass fiber (GF) framework, size-/conductivity-controlled partially reduced graphene oxide (PrGO), and a Cu substrate (PrGO–GF/Cu). Due to the synergistic interplay between the 3D GF alleviating volume fluctuation and PrGO with desirable conductivity, the PrGO–GF/Cu host mitigates the Li top plating and guides preferential Li deposition/dissolution at the bottom of the structure. As a result, the PrGO–GF/Cu exhibits substantially improved electrochemical performance in coulombic efficiency, symmetric cell, and LiFePO4 full cell tests. Experimental and theoretical studies reveal that modulating the electrical conductivity of the framework within an optimal range is an easy and effective way of suppressing Li top plating and facilitating Li bottom plating/stripping. This work demonstrates the importance of controlling the electrical conductivity to enable reversible behavior of Li in the Li-metal host anode, and a facile method to fabricate a 3D host that prevents Li top plating.

All-solid-state lithium-ion batteries (ASLBs) employing sulfide solid electrolytes are considered a promising alternative to conventional lithium-ion batteries (LIBs) from the perspectives of safety and high energy density. From a practical point of view, the development of sheet-type electrodes employing alternative electrode materials by scalable fabrication is of prime importance. While Si has been extensively studied for next-generation LIBs, reports on ASLBs are scarce. Herein, we fabricate sheet-type Si composite electrodes by infiltrating conventional LIB electrodes with solid electrolytes using a homogeneous Li6PS5Cl-ethanol solution. Further, we systematically investigate effects of the particle size (micro- vs. nano-Si) and polymeric binders (polyvinylidene fluoride vs. polyacrylic acid/carboxymethyl cellulose) on the electrochemical performance of ASLBs under varying external pressures (140, 20, and 5 MPa) upon cycling. Owing to intimate ionic contacts enabled by liquefied solid electrolytes, the Li6PS5Cl-infiltrated Si electrodes show higher capacities of over 3000 mA h g−1 at 0.25 mA cm−2 and 30 °C as compared with conventional dry-mixed electrodes. At 20 MPa, the Si electrodes using micro-Si and polyvinylidene fluoride show marginal degradation of performance. The high energy density of 338 W h kg−1 of LiCoO2/Si ASLBs fabricated using the Li6PS5Cl-infiltrated electrodes is demonstrated, highlighting the prospect of high-energy practical ASLBs.

A new discrete bis-dithiolene complex, [PPh4]2[Zn(DMED)2] (1; DMED = 1,2-dicarbomethoxy-1,2-dithiolate) with sulfur-based radical character was synthesized and structurally characterized. Complex 1 is stable and exhibits a square planar geometry around the zinc metal. 1 forms nanospheres through a one-pot water-induced self-assembly in a mixture of solvents (acetonitrile–water). These nanospheres were further decorated with water-soluble carbon nanotubes (wsCNTs) through hydrogen bonding between the peripheral –COOCH3 groups of 1 and surfacial carboxyl groups of wsCNTs to assemble into a spherical nanocomposite. The as-prepared nanocomposite showed fluorescence emissions in visible region due to the separation of energy states of the nanospheres assisted by wsCNTs, suggesting the future possibilities of these new materials for use in biomedical application.

Lithium-sulfur (Li-S) batteries have attracted extensive attention as a promising energy storage technology owing to their high theoretical capacity and energy density coupled with high cost efficiency. Despite these advantages, Li-S batteries still face problems in the shuttling behavior of soluble lithium polysulfides and the electrically insulating nature of sulfur, which has motivated considerable efforts toward developing conductive nanomaterials to improve electrochemical performances. In this study, microporous N, S dual-doped carbon materials based on a basic dye compound, methylene blue, were prepared via plasma engineering and carbonization process. Experimental and theoretical investigations revealed that an introduction of the carbon coated separators, denoted as PPMB interlayers, in Li-S batteries resulted in reduced cell polarization and effectively alleviated the lithium polysulfide shuttling behavior, leading to a high specific capacity of 1,329 mAh g−1 and retained specific capacity of 669 mAh g−1 after 100 cycles at 0.3C. This work highlights the potential application of this heteroatom-doped carbon material in Li-S batteries, as well as the viability of dye compound-derived carbon materials in energy storage devices.

The electrical relaxation and polarization phenomena of electrospun PVDF (P)/Nafion (N) blended fiber mats ([P/N0.9]M and β–[P]M) and membranes ([P/N0.9]MM) are compared with those of the solvent-c...

We prepared the polyethylene oxide (PEO)-based composite membrane electrolytes which contained the specialized ionic liquids and the inorganic filler of Li7La3Zr2O12 (LLZO). Mixtures of ionic liquids and tetragonal inorganic fillers were used as additives to prepare composite electrolytes for an application of all solid-state lithium ion batteries (ASLBs). In order to improve the ionic conductivity of composite membranes, we studied the structural change and the electrochemical behaviors as a function of the amounts of solvated ionic liquids (ILs). The addition effect of solvated ILs showed the higher ionic conductivity such as 10−4 S/cm at 55 °C by reducing the crystalline character of polymer based composite, resulting in the enhanced ion conducting property. The hybrid composite membranes were successfully made in flexible form, and have an excellent thermal and electrochemical stability. Finally, the electrochemical performance of the half-cell was evaluated, and it was confirmed that the ion-conducting characteristics were influenced and controlled by the effect of ILs.

Nafion ® perfluorosulfonic acid (PFSA) and poly(vinylidene fluoride) (PVDF) were electrospun simultaneously as a polymer solution mixture using a single needle spinneret. The nanofiber morphology was highly unusual, with bundled 2–5 nm fibril strands of Nafion and PVDF aligned along the fiber axis. Membranes were made from fiber mats by a simple hot-pressing step, followed by thermal annealing, where the fibril morphology of Nafion and PVDF in the original nanofibers was retained in the membrane. The PVDF component in the final membrane served three roles, as an electrospinning carrier polymer for PFSA, a mechanical reinforcement, and a hydrophobic (uncharged) component to limit PFSA ionomer swelling. A series of single-fiber membranes with Nafion/PVDF contents ranging from 40/60 to 90/10 wt%/wt% were prepared, characterized, and evaluated for use in a regenerative hydrogen/bromine fuel cell. As expected, there was a decrease in proton conductivity, water/electrolyte swelling, and Br 2 /Br 3 - permeability with increasing PVDF content. Membrane conductivity was lower than expected based on the weight fraction of PVDF, due presumably to an unusually large fraction of highly structured water. Nevertheless, a single-fiber Nafion/PVDF membrane with a thickness of 18 µm and an 80/20 wt%/wt% Nafion/PVDF composition performed well in a H 2 /Br 2 regenerative fuel cell due to a combination of low area-specific resistance and low Br 2 /Br 3 - crossover. Thus, with an electrolyte containing 0.9 M Br 2 in 1.0 M HBr, the maximum power output was 46% higher than that with a Nafion 212 membrane (1.31 vs. 0.90 W/cm 2 ).

All-solid-state batteries (ASSBs) have lately received enormous attention for electric vehicle applications because of their exceptional stability by engaging all-solidified cell components. However, there are many formidable hurdles such as low ionic conductivity, interface instability, and difficulty in the manufacturing process, for its practical use. Recently, carbon, one of the representative conducting agents, turns out to largely participate in side reactions with the solid electrolyte, which finally leads to the formation of insulating side products at the interface. Although the battery community mentioned that parasitic reactions are presumably attributed to carbon itself or the generation of electronic conducting paths lowering the kinetic barrier for reactions, the underlying origin for such reactions as well as appropriate solutions have not been provided yet. In this study, for the first time, it is verified that the functional group on carbon is an origin for causing negative effects on interfacial stability and a graphitized hollow nanocarbon as a promising solution for improving-electrochemical performance is introduced. This work offers an invaluable lesson that a relatively minor part, such as a conducting agent, in ASSBs sometimes gives more positive impact on improving electrochemical performance than huge efforts for resolving other parts.

A new type of polymer blend, prepared by electrospinning nanofibers containing the immiscible polymers polyvinylidene fluoride (PVDF, 10 wt%) and Nafion® perfluorosulfonic acid (90 wt%), has been characterized experimentally. The internal nanofiber morphology is unique and unlike a normal blend, with individual phase-separated and randomly distributed fibrils of Nafion and PVDF (∼2-7 nm in diameter) that are bundled together and aligned in the fiber axis direction (where the fiber diameter is ∼500 nm). This morphology is retained when fiber mats are hot-pressed into dense films. The physicochemical properties of the electrospun blended fibers are also highly unusual and unanticipated. As shown in this study, each polymer component influences the thermal and structural behavior of the other, especially in the dry state. Thus, dry composite polymer mats and membranes exhibit properties and attributes that are not observed for either pure PVDF or pure Nafion. Experimental results indicate that: (i) PVDF imparts conformational constraints on the polytetrafluoroethylene (PTFE) backbone chains of Nafion, resulting in an increased 21 helical conformation that effects Nafion's water uptake and thermal properties; and (ii) dipole-dipole interactions between PVDF polymer chains and Nafion make the β-phase polymorph of PVDF much more stable at elevated temperatures. Such "reciprocal templating" in electrospun fibers may not be unique to Nafion and PVDF, thus the procedure represents a new method of creating nanostructured multi-component polymer materials with innovative features.

To compare the visual field (VF) sensitivity according to the presence of parapapillary deep-layer microvasculature dropout (MvD_P) and focal lamina cribrosa (LC) defect.Among 158 open-angle glaucoma patients, 4 groups were formed according to the presence of MvD_P and focal LC defect determined by optical coherence tomography (OCT) angiography and by enhanced depth imaging spectral-domain OCT, respectively: (1) eyes without either focal LC defect or MvD_P (group 1); (2) eyes with focal LC defect but no MvD_P (group 2); (3) eyes without focal LC defect but with MvD_P (group 3); (4) eyes with both focal LC defect and MvD_P (group 4). VF sensitivity and retinal nerve fiber layer (RNFL) thickness were compared among the 4 groups for global area and 6 sectors.Both RNFL thickness and VF sensitivity differed among the 4 groups in all areas other than the nasal and superonasal sectors for RNFL thickness. On post hoc analysis, eyes with MvD_P (groups 3 and 4) had significantly worse VF sensitivity than group 2 [P0.05, 1-way analysis of variance (ANOVA)] in all areas except the superotemporal and temporal sectors, whereas the RNFL thicknesses did not differ (P0.05, 1-way ANOVA) in any areas except the superotemporal sector.Eyes with MvD_P had worse VF sensitivity than those without MvD_P, and VF difference was more distinguished than differences of axonal loss and focal LC change. Further studies on the temporal relationship between the MvD_P and glaucomatous VF progression are warranted.

In Vietnam, there are about 17,000 pig farms with over 500 pigs, and less than 0.3% of them have a biogas facility. Biogas production from this size is about 50,000 m3/year. This biogas is methane-rich, based on a typical composition of 60–70% methane. However, trace amounts of H2S are also present, which hinder their use as it is very toxic and corrodes the equipment. In this study, an adsorption system using iron-based adsorbent (FeOOH) was developed to remove hydrogen sulfide from biogas at the Thanh Hung pig farm (Thanh Oai District, Hanoi, Vietnam). The initial biogas contained high CH4 concentration of 72%, and the H2S was at the rage of 1995 to about 4000 ppm. Based on the results obtained from the study, it could be seen that FeOOH has high capacity for H2S purification from biogas. The adsorption capacity of the FeOOH was estimated to be up to 0.18 g H2S/g FeOOH. The H2S concentration in the effluent was almost lower than 5 ppm which was suitable for electric generators. In this study, the purified biogas was used for a small electricity generator of 3.5 KVA. As a result, the biogas consumed was about 0.64 m3 per 1 kWh of electricity produced. This amount could fully meet the demand of electricity of a farm. In conclusion, the potential of market for biogas production and consumption in Vietnam is huge. Biogas purification technology for electricity generation, therefore, plays an important role in the biogas market of Vietnam.

Nanofiber composite proton exchange membranes were fabricated and their properties measured, for possible use in a regenerative hydrogen/bromine fuel cell. The membranes were prepared from dual nanofiber mats, composed of Nafion® perfluorosulfonic acid (PFSA) ionomer for proton transport and polyvinylidene fluoride (PVDF) for mechanical reinforcement. Two composite membranes structures containing Nafion volume fractions ranging from 0.30 to 0.65 were investigated: (1) Nafion nanofibers embedded in a PVDF matrix (N(fibers)/PVDF) and (2) PVDF nanofibers embedded in a Nafion matrix (N/PVDF(fibers)). The in-plane conductivity for films equilibrated in water and 2.0 M HBr scaled linearly with Nafion volume fraction for both morphologies. The through-plane proton conductivity of N(fibers)/PVDF membranes in water was lower than that of N/PVDF(fibers) films with the same Nafion content for films with less than 55 vol% Nafion, e.g., 0.03 S/cm for N(fibers)/PVDF membrane vs. 0.04 S/cm for N/PVDF(fibers) membrane at 40 vol% Nafion. N(fibers)/PVDF membranes exhibited excellent Br2/ Br 3 − barrier properties with a reasonable membrane resistance, e.g., a N(fibers)/PVDF membrane with 40 vol% Nafion and a thickness of 48 µm had the same area-specific-resistance as Nafion® 115 (0.13 Ω cm2) but its steady-state Br2/ Br 3 − crossover flux was 3.0 times lower than that of Nafion 115 (1.43×10−9 mol/s/cm2 vs. 4.28×10−9 mol/s/cm2).

To investigate the tendency of Li + exchange from polar organic solvents, Li + -ion exchange into zeolite Y (Si/Al = 1.56) was attempted by undried methanol (crystal 1) and formamide (crystal 2) solvent. Two single crystals of Na-Y were treated with 0.1 M LiNO3 in each of the two solvents at 323 K, followed by vacuum dehydration at 723 K. Their structures were determined by single-crystal synchrotron X-ray diffraction techniques in the cubic space group Fd3m, at 100(1) K. In both structures, Li + for Na + ions filled preferentially sites I’ and II. The remaining Na+ ions occupied sites I’, II, and III’ in both structures, in additional to above sites, and Na + ions occupied site I in crystal 2. While the 68 % exchange of Li + for Na + was achieved from undried methanol, only 40 % exchange was observed from undried formamide, indicating that the undried methanol was more effective than undried formamide as solvent for Li + exchange under the conditions employed.

Highly concentrated, molten mixtures of lithium bis(trifluoromethanesulfonyl)amide (Li[TFSA]) and ether solvents (tetrahydrofuran (THF), monoglyme (G1), diglyme (G2), and triglyme (G3)) were investigated as electrolytes for Li batteries. To compare the electrochemical reactions in the electrolytes with different solvents, the ratio of ether–oxygen atoms and Li+ ([O]/[Li]) in the electrolytes was fixed at four. The capacity of a Li–LiCoO2 cell with [Li(THF)4][TFSA] dramatically decreased upon charge/discharge cycling, whereas [Li(G3)1][TFSA] allowed the cell to have a stable charge–discharge cycles and a Coulombic efficiency of greater than 99% over 100 cycles. Corrosion of the Al current collector of the cathode was also affected by the composition of the electrolytes. Persistent Al corrosion took place in [Li(THF)4][TFSA] and [Li(G1)2][TFSA], which contain shorter ethers, but the corrosion was effectively suppressed in [Li(G3)1][TFSA]. Furthermore, lithium polysulfides, which are formed as discharge inte...

Research efforts on proton conducting polymeric membranes for fuel cells are discussed and future R&D directions are identified. The key membrane performance issues for hydrogen/air fuel cells are high proton conductivity under dry conditions, low gas crossover, and good mechanical/chemical stability. For direct liquid methanol fuel cells, there is a need for highly durable membranes with a high proton conductivity and low methanol crossover. Fluorinated ionomers continue to dominate the fuel cell membrane landscape and it is unlikely that a hydrocarbon polymer will supplant these materials anytime soon, especially for automotive applications. Promising strategies for improving membrane performance and durability in a hydrogen/air fuel cell include the use of ultra-low equivalent weight semicrystalline ionomers, covalently attaching conductive and water retaining particles to an ionomer, and adding a porous/nanofiber reinforcements to minimize in-plane swelling and shrinking. For direct methanol fuel cells, the best commercial material is Nafion 117, but pre-stretched films of recast Nafion outperform all commercial membranes and show great potential.

A variety of binary mixtures of aprotic ionic liquids (ILs) and lithium salts were thoroughly studied as electrolytes for rechargeable lithium–sulfur (Li–S) batteries. The saturation solubility of sulfur and lithium polysulfides (Li2Sm), the active materials in the Li–S battery, in the electrolytes was quantitatively determined, and the performance of the Li–S battery using the electrolytes was also investigated. Although the solubility of nonionic sulfur was low in all of the electrolytes evaluated, the solubility of Li2Sm in the IL-based electrolyte was strongly dependent on the anionic structure, and the difference in the solubility could be rationalized in terms of the donor ability of the IL solvent. Dissolution of Li2Sm in the ILs with strong donor ability was comparable to that achieved with typical organic electrolytes; the strongly donating IL electrolyte did not prevent redox shuttle reaction in the Li–S cells. The battery performance was also influenced by unfavorable side reactions of the anio...

A series of equimolar mixtures of Li salts (LiX) and glymes (triglyme (G3) and tetraglyme (G4)), [Li(glyme)]X with different anions (X: [N(SO2C2F5)2] = [BETI]; [N(SO2CF3)2] = [TFSA]; [CF3SO3] = [OTf]; BF4; NO3), were used as electrolytes to study the anionic effects of [Li(glyme)]X on the performance of lithium–sulfur (Li–S) batteries. The dissolution of lithium polysulfides (Li2Sm), which are discharge products of elemental sulfur, was significantly suppressed in the solvate ionic liquid (IL) electrolytes, as seen in [Li(G4)][BETI] and [Li(glyme)][TFSA], wherein all of the glymes participated in the formation of the complex cation [Li(glyme)]+. It was found that NO3 anions were irreversibly reduced at the composite cathode during discharge and BF4 anions formed unexpected byproducts through a chemical reaction with the polysulfide anions. Successful charge/discharge of Li–S cell could not be performed in [Li(glyme)]X in the presence of these anions because of the undesired side reactions. The solvate IL ...

Multi-mode atomic force microscopy (AFM) was used to differentiate between Nafion® and electrospun composite nanofiber membranes. The results of this experiment will guide the design of new class of proton exchange membranes (PEM). Characterizing the electrospun composite nanofiber membranes will allow us to identify properties that are ideal for the next generation PEM. Engineering the proton conducting membrane for a PEM fuel cell that allows protons and inhibits other species to cross is vital to its long-term operation. When species other than protons are allowed to cross a PEM, issues arise in the form of electrode flooding, adverse chemical reactions, and reduced fuel cell efficiency.

A room temperature ionic liquid (RTIL), N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)amide ([DEME][TFSA]), was used as an electrolyte solvent for lithium–sulfur (Li–S) batteries. Li[TFSA] was dissolved into [DEME][TFSA] to prepare the electrolytes, and a molecular solvent—tetraethylene glycol dimethyl ether (TEGDME)—was used for Li[TFSA] as a reference. Discharge–charge tests of Li–S cells using these electrolytes were carried out. The discharge–charge cycle stability and Coulombic efficiency of a cell with an RTIL electrolyte were found to be surprisingly superior to those of a cell with TEGDME electrolyte. The poor cycle stability of the cell with the TEGDME electrolyte was attributed to the dissolution of lithium polysulfides (Li2Sm), which were generated as reaction intermediates through a redox process at the S cathode in the Li–S cell. RTIL has low donor ability owing to the weak Lewis basicity of [TFSA]− anion, whereas conventional ether-based molecular solvents such...

Innovation in the design of electrolyte materials is crucial for realizing next-generation electrochemical energy storage devices such as Li–S batteries. The theoretical capacity of the S cathode is 10 times higher than that of conventional cathode materials used in current Li–ion batteries. However, Li–S batteries suffer from the dissolution of lithium polysulfides, which are formed by the redox reaction at the S cathode. Herein, we present simple solvate ionic liquids, glyme–Li salt molten complexes, as excellent electrolyte candidates because they greatly suppress the dissolution of lithium polysulfides. The molten complexes do not readily dissolve other ionic solutes, which leads to the stable operation of the Li–S battery over more than 400 cycles with discharge capacities higher than 700 mAh g-sulfur−1 and with coulombic efficiencies higher than 98% throughout the cycles. Such high performance has not been realized to the best of our knowledge. Furthermore, the addition of a nonflammable fluorinated solvent, which does not break the solvate structure of the glyme–Li salt molten complexes, greatly enhances the power density of the Li–S battery. The strategic design of electrolyte properties provides opportunities for the development of new electrochemical devices with many different electrode materials.

The physicochemical and electrochemical properties of the binary ionic liquid (IL), lithium bis(trifluoromethylsulfonyl)amide (LiTFSA) dissolved in N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethylsulfonyl)amide (DEMETFSA), were investigated. The ionic conductivity of the binary IL decreased with an increase in LiTFSA concentration. The self-diffusion coefficients of Li+, DEME+, and TFSA− dissolved in the IL were measured by using the pulsed-field-gradient spin-echo (PGSE) NMR method. The self-diffusion coefficient of each ionic species was also found to decrease with increasing concentration of LiTFSA. The limiting current density in the IL electrolyte was evaluated by chronoamperometry using symmetric Li|IL|Li cell. The results suggest that the diffusion process of Li(I) in the IL dominates the limiting current density in the cell. The highest limiting current density is achieved at a concentration of 0.64 mol dm−3 of LiTFSA.

Siliceous MCM-41 and various organo-functionalized MCM-41s have been successfully synthesized by co-condensation method with/without the addition of NaF. The results of XRD, FT-IR and TG/DTG analyses show that the organo-functional groups incorporated into silicate framework of MCM-41 have been stably anchored to the silicate framework even after surfactant extraction and subsequent sulfonation. It also shows that the addition of NaF to synthesis mixture could lead to well-resolved MCM-41 but the incorporation of organo-functional groups could be disturbed by F − anions, especially for vinyl group, enhancing the polycondensation than co-condensation. The proton conductivities of composite membranes fabricated by as-synthesized siliceous MCM-41s synthesized with/without the addition of NaF (M41F and M41) are lower than those of composite membranes fabricated by their calcined MCM-41s synthesized with/without the addition of NaF (CM41F and CM41) regardless of the addition of NaF while their methanol permeability are opposite, mainly due to pore blocking by surfactant. The results also clearly show that the higher and increasing methanol permeability of composite membrane fabricated with CM41 than fabricated with CM41F with powder content is ascribed to the combined effect of larger pore and broader pore size distribution and poorer adhesion between powder and Nafion dispersion. FT-IR and TGA results clearly show that the methanol permeability of composite membranes fabricated with various organo-functinalized- and sulfonated-MCM-41 strongly depends on the residual void space within the pore channel of MCM-41 resulting from the amount of incorporated organo-functional groups and hydrophilicity of sulfonic groups attached to organo-functional groups. It is also seen that the synthesis condition of MCM-41 such as the addition of NaF significantly affects the degree of organo-functionalization, especially for vinyl groups and thus sulfonation.

Zeolite beta was successively synthesized in the presence of TEABr as organic template within 36 h under static and stirred conditions at 423 K. In order to clearly demonstrate the effects of individual component and interaction between components on the crystallization of zeolite beta using TEABr, a ternary compositional diagram for TEABr, Al 2 O 3 and Na 2 O was drawn at constant SiO 2 and H 2 O contents. There are mainly three compositional zones in which zeolites, beta, ZSM-5 and mordenite are formed. The results suggest that Na + cation should have acted as structure-directing agent as well as charge balancing for AlO 2 − , leading the crystallization toward the formation of mordenite or ZSM-5 depending on its content. The results clearly show that the crystallization toward pure zeolite beta becomes favorable at lower Al 2 O 3 content. In addition, it is interesting to notice that Na 2 O and Al 2 O 3 contents would play key roles simultaneously in the crystallization toward the formation of pure zeolite beta. The results of thermal analysis show that TEA + ion also partially acts as charge-balancing agent depending on Al content, that is, it is more likely to interact with Si–O − rather than with Al–O − at lower Al content, thus resulting in the more decomposition of TEA + ions interacting with Si–O − at lower Al content in temperature range between 473 and 623 K. The kinetic study based on 3Na 2 O–18TEABr–0.8Al 2 O 3 –25SiO 2 –440H 2 O was conducted at 413, 418 and 423 K, respectively, and the results suggest that as long as a correct crystallization temperature is applied to the synthesis of zeolite beta, the crystallization of zeolite beta does not seem to be so sensitive to temperature.

Zeolite/Nafion composite membranes with high proton selectivity were successfully fabricated using the solution-casting method. The types of zeolites are nano-sized and large sized Na-ZSM-5, H-ZSM-5, and their ball-milled ones. Two different schemes of experiments were conducted depending on the type of solvent. In case of using as-received Nafion® ionomer dispersions, the experimental results clearly show that the proton conductivity of zeolite composite membrane using either H-type or Na-type ZSM-5 depends on the type of solvent. It is thought that when propanol and water as the solvents were used, more hydrophilic H-type ZSM-5 seems to have been more randomly dispersed into hydrophobic region rather than hydrophilic ionic clustered channels within Nafion. Therefore, H-type ZSM-5 existing near hydrophobic region seems to provide additional path for proton migration but weakening the mechanical strength. These composite membranes show higher water uptake than commercial Nafion® 115, strongly suggesting better water retention ability of zeolite. The most interesting result is that the methanol permeability has decreased with increasing zeolite contents even when the proton conductivity increased, and the proton selectivities of these composite membranes expressed as characteristic factor were higher than that of Nafion® 115. In case of using a mixture of high boiling point DMF and ethanol as the solvent, unlike the previous case where no DMF was used, the proton conductivity slightly dropped with increasing zeolite contents. These results should have been attributed to a blocking effect of zeolite particles surrounded by inversely oriented hydrophilic micelles of Nafion. However, the values of proton conductivity of most composite membranes were significantly higher than that of Nafion® 115, and methanol permeability also decreased with increasing zeolite contents. The significantly lower methanol permeability of the composite membrane fabricated with DMF as the solvent is probably due to the more effective blocking effect of H-ZSM-5 for ionic clustered channels as well as difficult transport of methanol through zeolite pores. In case of the composite membranes containing ZSM-5 with large crystal size, it is found that the methanol permeability has increased considerably with the increasing of zeolite contents due to void fractions between polymer phases and zeolite particles. In case of using ball-milled ZSM-5 with small crystal size, however, the value of characteristic factor tends to increase with increasing zeolite contents. Consequently, it is seen that the characteristic factor of Zeolite/Nafion composite membranes was much higher than Nafion® 115. The results obtained throughout this study strongly suggest that zeolites with small crystal size and high hydrophilicity are very prospective for composite membrane for direct methanol fuel cells in the future.

A large pored variety of titanium silicate, ETS-10 was synthesized to investigate the effects of (Na + K)/Na molar ratio on the crystallization and phase purity using cost efficient titanium oxysulfate as the titanium source under stirring at 200 rpm and to calculate activation energy. The results showed that the (Na + K)/Na molar ratio significantly affects the crystallization and phase purity. In addition, regardless of silica and titanium sources, the morphology of ETS-10 synthesized under stirred condition is quite different from that synthesized under static condition showing a small spherical shape, and seems to be significantly affected by stirring. The composition with the shortest reaction time to reach the 100% crystallinity and purity for different silica and titanium source was chosen and applied to the kinetic study. All the experiments for kinetic study were carried out at 433, 453 and 473 K, respectively. The activation energies for three different stages, nucleation, transition and crystallization were calculated using the modified Avrami–Erofeev equation. The results of kinetic study also suggest that the effect of titanium source is more significant than that of silica source. As a comparison, the temperature dependency for titanium oxysulfate is less sensitive than for titanium sulfate except the lowest temperature (i.e., 433 K) studied in this study, suggesting that minimum temperature should be maintained to proceed the crystallization at reasonable rate for titanium oxysulfate. The modified Avrami–Erofeev equation to three different stages, nucleation, transition and crystallization for rapid crystallization seems to be excellent tool to predict the crystallization of ETS-10.

The regenerative H2/Br2-HBr fuel cell, utilizing an oxidant solution of Br2 in aqueous HBr, shows a number of benefits for grid-scale electricity storage. The membrane-electrode assembly, a key component of a fuel cell, contains a proton-conducting membrane, typically based on the perfluorosulfonic acid (PFSA) ionomer. Unfortunately, the high cost of PFSA membranes and their relatively high bromine crossover are serious drawbacks. Nanofiber composite membranes can overcome these limitations. In this work, composite membranes were prepared from electrospun dual-fiber mats containing Nafion® PFSA ionomer for facile proton transport and an uncharged polymer, polyphenylsulfone (PPSU), for mechanical reinforcement, and swelling control. After electrospinning, Nafion/PPSU mats were converted into composite membranes by softening the PPSU fibers, through exposure to chloroform vapor, thus filling the voids between ionomer nanofibers. It was demonstrated that the relative membrane selectivity, referenced to Nafion® 115, increased with increasing PPSU content, e.g., a selectivity of 11 at 25 vol% of Nafion fibers. H2-Br2 fuel cell power output with a 65 μm thick membrane containing 55 vol% Nafion fibers was somewhat better than that of a 150 μm Nafion® 115 reference, but its cost advantage due to a four-fold decrease in PFSA content and a lower bromine species crossover make it an attractive candidate for use in H2/Br2-HBr systems.

Objective : The purpose of study was to evaluate the feasibility of brain magnetic resonance (MR) images of the rat obtained using a 1.5T MR machine in several blood-brain barrier (BBB) experiments. Methods : Male Sprague-Dawley rats were used. MR images were obtained using a clinical 1.5T MR machine. A microcatheter was introduced via the femoral artery to the carotid artery. Normal saline (group 1, n = 4), clotted autologous blood (group 2, n = 4), triolein emulsion (group 3, n = 4), and oleic acid emulsion (group 4, n = 4) were infused into the carotid artery through a microcatheter. Conventional and diffusion-weighted images, the apparent coefficient map, perfusion-weighted images, and contrast-enhanced MR images were obtained. Brain tissue was obtained and triphenyltetrazolium chloride (TTC) staining was performed in group 2. Fluorescein isothiocyanate (FITC)-labeled dextran images and endothelial barrier antigen (EBA) studies were performed in group 4. Results : The MR images in group 1 were of good quality. The MR images in group 2 revealed typical findings of acute cerebral infarction. Perfusion defects were noted on the perfusion-weighted images. The MR images in group 3 showed vasogenic edema and contrast enhancement, representing vascular damage. The rats in group 4 had vasogenic edema on the MR images and leakage of dextran on the FITC-labeled dextran image, representing increased vascular permeability. The immune reaction was decreased on the EBA study. Conclusion : Clinical 1.5T MR images using a rat depicted many informative results in the present study. These results can be used in further researches of the BBB using combined clinical MR machines and immunohistochemical examinations. 10.3340/jkns.2010.47.3.203

치은염 및 치주염이 진행되면서 치아 주위의 치조골의 파괴 및 치아상실을 초래할 수 있다. 질환 초기의 과정 중 에 적절한 치료가 동반된다면 치조골의 파괴 및 장기적이 고 지속적인 치료가 필요한 경우까지 가지 않을 수 있다. 치주질환은 잇몸의 초기 염증부터 시작한다. 생체 내에서 발생하는 모든 염증의 단계에는 면역세포들이 관여하는 데, 이 중에서 가장 많이 관여되는 대표적인 염증전구물질 로는 Interleukin-1β(IL-1β), Tumor Necrotic Factor (TNF-α) 등과같은사이토카인으로알려져있다. 그외에도 Interleukin4, Interleukin-6, Interleukin-10과 같은 많은 사이토카인들이 염증에 전반적으로 관여하고 있다. Cyclooxy-genase (COX2)는 IL-1β등의 cytokine에 의해 유도되며 염증반응과정에 서 핵심적인 역할을 하며, prostaglandin E2 (PGE2)의 촉진 제 역할로서 알려져 있다. 이와 같은 많은 염증전구인자의 발현에 초점을 맞추어져서 신약 개발 및 염증치료제를 개 발하였고, 개발진행중에있다. 그 중에서도 히알우론산은 점도가 높은 고분자의 점액다 당류(mucopolysaccharide)의 일종으로 관절액을 구성하는 성분물질로 알려져 있으며, 관절을 부드럽게 해주며 윤활 작용을 도와주는 기능이 있는 물질로 잘 알려져 있다. 이 러한 작용 때문에 정형외과, 피부과 그리고 안과영역에서 염증과정의 치유에 있어서 히알루론산의 역할에 대해 효 과가 이미 입증되어 있다. 특히 백내장 수술,퇴행성 관절 염, 방사선 상피염(Radio-epithelitis) 무릎관절의 관절염치 료에 있어서 유의성 있는 개선 효과가 있음이 임상 지표 로 보고되어 있다. 그러나 치과영역에서는 염증치료제로 쓰이는 히알우론산 제제의 염증 및 재생에 관한 연구는 결 박 준 우 134-010 서울특별시강동구길동 445 한림대학교강동성심병원구강악안면외과 Jun-Woo Park Department of Oral and Maxillofacial Surgery, College of Medicine, Hallym University Gil-Dong 445, Gangdong-Gu, Seoul, 134-010, Korea Tel: +82-2-2224-2333 Fax: +82-2-483-9647 E-mail: junpark@hanafos.com 마우스에서 히알우론산 나트륨이 항염효과에 미치는 영향에 관한 연구

Using spectroscopic ellipsometry electro-optic effect was studied in lead zirconate titanate (PZT) thin films grown epitaxially on Nb-doped SrTiO3(001) substrates by RF magnetron sputtering. A uniaxial multilayer model analysis was applied to extract the linear and quadratic electro-optic coefficients from the shifts in the ordinary and extraordinary refractive indices with electric field applied along the (001) direction. The effective linear and quadratic coefficients were measured as −134.6×10−12 m/V and 8.5×10−18 m2/V2, respectively, at a wavelength of 632.8 nm, while the individual linear electro-optic coefficients r33 and r13 were −157.1 and 22 pm/V, respectively. The existence of the linear electro-optic effect in unpoled PZT films was attributed to the presence of a built-in polarization and simultaneous poling during measurements.

The relationship between Li(I) transport property and the limiting current density was investigated in N-methyl-N-propylpyrrolidinium bis(trifluoromethylsulfonyl)amide (P13TFSA) at 30°C. The limiting current density in a LiTFSA/P13TFSA binary ionic liquid electrolyte was evaluated by chronoamperometry for a symmetric cell of Li|ionic liquid|Li, where the ionic liquid was incorporated in a porous polyethylene separator that was sandwiched between two Li electrodes. The diffusion process of Li(I) in the ionic liquid dominates the limiting current density in the cell. In addition to the Li(I) transport property of the electrolyte, the porosity and tortuosity of the separator has a significant effect on the limiting current density.