Fast ionic transport in solids

The discovery of inorganic solids with ionic conductivities comparable to those of aqueous electrolytes has revolutionized solid-state electrochemistry. Sodium beta alumina, a Na(+) conductor, and LixTiS(2), an intercalation compound with simultaneous Li(+) and electronic conductivity, are two of the best and most versatile fast ionic conductors. A wide variety of cations can replace Na(+) in beta alumina and Li(+) in LixTiS(2) and change the properties of the materials. Sodium beta alumina and LixTiS(2) are currently used in the development of high-energy density batteries for electric vehicles and electrical utility load leveling. Current research in solid ionic conductors is exploring new intercalation compounds, solid polymer electrolytes, and alkali ion and proton transport in crystalline solids.     

Multicompartment micelles from ABC miktoarm stars in water

By combining three mutually immiscible polymeric components in a mixed-arm star block terpolymer architecture, we have observed the formation of a previously unknown class of multicompartment micelles in dilute aqueous solution. Connection of water-soluble poly(ethylene oxide) and two hydrophobic but immiscible components (a polymeric hydrocarbon and a perfluorinated polyether) at a common junction leads to molecular frustration when dispersed in aqueous solution. The incompatible hydrophobic blocks form cores that are protected from the water by the poly(ethylene oxide) blocks, but both are forced to make contact with the poly(ethylene oxide) by virtue of the chain architecture. The structures that emerge depend on the relative lengths of the blocks and can be tuned from discrete multicompartment micelles to extended wormlike structures with segmented cores.     

高含量锂镧锆氧基复合固体电解质的制备及其性能研究

固态电解质具有优异的安全性能、工作温度范围宽、回收方便等优点,已成为新一代柔性电子器件中最具前景的电解质材料.为探索兼具高离子电导率和优良机械性能的固态电解质,将无机活性陶瓷锂镧锆氧（Lithium lanthanum zirconium oxide,LLZO）与改性聚离子液体复合,制备了一种性能优异的复合固态电解质.研究了LLZO与复合材料间结构的差异、LLZO的含量对复合固态电解质在离子电导率、机械性能的影响以及其抗压能力.结果表明,聚离子液体粘结剂的加入,赋予了固态电解质良好的柔顺性,并显著地提升了电解质的离子传输效率. 当复合固态电解质中LLZO为质量分数50%时,复合固态电解质的室温离子电导率达到最高值（1.45×10-4 S·cm-1）,比单一的LLZO固态电解质的离子电导率高了一个数量级以上. 用维氏硬度来表征复合固态电解质的抗压能力,发现当LLZO为质量分数50%时,复合固态电解质的硬度可以达到0.45 gf/μm2.     

PEO/CF双组分助留体系的助留机理

二元助留体系在非木质原料造纸中的助留效果较好,其中以PEO/CF二元助留体系为代表.简要介绍助留剂的发展,阐述PEO/CF双组分助留体系的作用机理,并对PEO用作助留剂进行了展望.     

Mesophase structure-mechanical and ionic transport correlations in extended amphiphilic dendrons

We have studied the self-assembly of amphiphilic dendrons extended with linear polyethylene oxide (PEO) chains and their ion complexes. Keeping the dendron core and linear PEO chain compatible allows for the combination of dendritic core-shell and conventional blockcopolymer characteristics for complex mesophase behavior. An unexpected sequence of crystalline lamellar, cubic micellar (Pm3n), hexagonal columnar, continuous cubic (Ia3d), and lamellar mesophases is observed. Multiple phase behavior within single compounds allows for the study of charge transport and mechanical property correlations as a function of structure. The results suggest an advanced molecular design concept for the next generation of nanostructured materials in applications involving charge transport.     

The collapse of free polymer chains in a network

The conformation of linear polymer chains trapped in a matrix of cross-linked polymer has been measured by neutron scattering. Three regimes were found depending on the length of the linear chain, Nl, with respect to the mesh size of the network, N(c). When N(c) > Nl, the radius of gyration, R(g), of the linear chain is the same as that observed in the uncrosslinked melt. When N(c) < Nl, R(g) shrinks according to the scaling relation R(g)(-1) approximately N(c)(-1) that has been predicted for isolated polymer chains trapped in a field of random obstacles. When N(c) < Nl the linear chains are observed to segregate.     

Crystal Structure of Kernite, Na2B4O6(OH)2 {middle dot} 3H2

Kernite, Na(2)B(4)O(6)(OH)(2). .3H(2)0, contains parallel infinite chains of the borate polyanion[B(4)O(6)(OH)(2)](n)(2n-). The chains are composed of six-membered rings containing one boron-oxygen triangle and two boron-oxygen tetrahedra. The rings are linked through commonly shared boron-oxygen tetrahedra.     

包裹姜根油的多种纳米颗粒的制备及质量评价

以大豆磷脂、聚乙交酯丙交酯(PLGA)和聚乙二醇(PEG)3种原料成功制备了包裹难溶于水的植物提取物姜根油(GRO)的纳米脂质体、PLGA纳米颗粒和PEG纳米颗粒,并对3种不同载体制备的纳米制剂的形貌、大小、Zeta电位,包封率及物理稳定性等进行了考察.研究结果表明3种纳米颗粒各有优缺点,可以根据不同的条件和不同的需要制备不同的颗粒,为开发新型的难溶药用植物提取物的理想药剂提供了实验依据.     

A main group metal sandwich: five lithium cations jammed between two corannulene tetraanion decks

Lithium-coordinated polyaromatic anions such as tetrareduced corannulene, C(20)H(10)(4-) (1(4-)), are useful substrates to model and ultimately improve the graphitic electrodes in lithium-ion (Li(+)) batteries. Previous studies suggested that 1(4-) forms dimers encasing four Li(+) ions in solution. Here, we report a single-crystal x-ray diffraction analysis confirming the formation of a sandwich-type supramolecular aggregate with a high degree of alkali metal intercalation. In contrast to the prior model, our data reveal that five Li(+) ions are sandwiched between the two tetrareduced corannulene decks, and (7)Li nuclear magnetic resonance spectroscopy delineates a conserved structure in tetrahydrofuran solution. Remarkably, the sandwich is robust in both solution and solid states even in the presence of crown ethers that compete for Li(+) coordination. These results should help elucidate Li(+) intercalation motifs between curved carbon surfaces more broadly.     

Templating of mesoporous molecular sieves by nonionic polyethylene oxide surfactants

Mesoporous silica molecular sieves have been prepared by the hydrolysis of tetraethylorthosilicate in the presence of low-cost, nontoxic, and biodegradable polyethylene oxide (PEO) surfactants, which act as the structure-directing (templating) agents. This nonionic, surfactant-neutral, inorganic-precursor templating pathway to mesostructures uses hydrogen bonding interactions between the hydrophilic surfaces of flexible rod- or worm-like micelles and Si(OC(2)H(5))(4-x)(OH)(x) hydrolysis products to assemble an inorganic oxide framework. Disordered channel structures with uniform diameters ranging from 2.0 to 5.8 nanometers have been obtained by varying the size and structure of the surfactant molecules. Metal-substituted silica and pure alumina mesostructures have also been prepared by the hydrolysis of the corresponding alkoxides in the presence of PEO surfactants. These results suggest that nonionic templating may provide a general pathway for the preparation of mesoporous oxides.     

A molecular-based magnet with a fully interlocked three-dimensional structure

A compound has been synthesized with the formula (rad)(2)Mn(2)[Cu(opba)](3)(DMSO)(2).2H(2)O, where rad(+) is 2-(4-N-methylpyridinium)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, opba is orthophenylenebis(oxamato), and DMSO is dimethyl sulfoxide. It consists of two nearly perpendicular graphite-like networks with edge-sharing Mn(II)(6)Cu(II)(6) hexagons. The two networks are fully interlocked with the same topological relationship as that between adjacent rings of a necklace. The compound has three kinds of spin carriers: Mn(II) and Cu(II) ions, antiferromagnetically coupled through oxamato bridges, and rad(+) radical cations, bridging the Cu(II) ions through the nitronyl nitroxide groups and forming Cu-rad chains. The temperature dependence of the magnetization reveals that below 22.5 K, the compound behaves as a magnet.     

Orientational Disorder of C60 in Li2CsC60

The x-ray diffraction of the nonsuperconducting ternary fulleride Li(2)CsC(60) reveals at room temperature a face-centered-cubic (Fm3m) disordered structure that persists to a temperature of 13 Kelvin. The crystal structure is best modeled as containing quasispherical [radius of 3.556(4) angstroms] C(60)(3-) ions, in sharp contrast to their orientational state in superconducting face-centered-cubic K(3)C(60) (merohedral disorder) and primitive cubic Na(2)CsC(60) (orientational order). The orientational disorder of the carbon atoms on the C(60)(3-) sphere was analyzed with symmetry-adapted spherical-harmonic functions. Excess atomic density is evident in the <111> directions, indicating strong bonding Li(+)-C interactions, not encountered before in any of the superconducting alkali fullerides. The intercalate-carbon interactions and the orientational state of the fullerenes have evidently affected the superconducting pair-binding mechanism in this material.     

Direct electrochemical measurements inside a 2000 angstrom thick polymer film by scanning electrochemical microscopy

An extremely small, conically shaped Pt microelectrode tip (with a radius of 30 nanometers) and the precise positioning capabilities of the scanning electrochemical microscope were used to penetrate a thin (200 nanometers) polymer film and obtain directly the standard potential and kinetic parameters of an electrode reaction within the film. The thickness of the film was determined while it was immersed in and swollen by an electrolyte solution. The film studied was the perfluorosulfonate Nafion containing Os(bpy)(3)(2+) (bpy, 2,2'-bipyridine) cast on an indium tin oxide surface. The steady-state response at the ultramicroelectrode allowed direct determination of the rate constant for heterogeneous electron transfer K(o) and the diffusion coefficient D without complications caused by transport in the liquid phase, charge exchange at the liquid-polymer interface, and resistive drop.     

Adhesion and friction mechanisms of polymer-on-polymer surfaces

The adhesion and friction of smooth polymer surfaces were studied below the glass transition temperature by use of a surface forces apparatus. The friction force of a crosslinked polymer was orders of magnitude less than that of an uncrosslinked polymer. In contrast, after chain scission of the outermost layers, the adhesion hysteresis and friction forces increase substantially. These results show that polymer-polymer adhesion hysteresis and friction depend on the dynamic rearrangement of the outermost polymer segments at shearing interfaces, and that both increase as a transition is made from crosslinked surfaces to surfaces with long chains to surfaces with quasi-free ends. The results suggest new ways for manipulating the adhesion and friction of polymer surfaces by adjusting the state of the surface chains.     

Luminescence Enhancement by the Introduction of Disorder into Poly(p-phenylene vinylene)

A method is described for increasing luminescence in poly(p-phenylene vinylene) (PPV) light-emitting diodes. Cis linkages were engineered into the PPV chain. These linkages interrupt conjugation and interfere with the packing of the polymer chains, which results in the formation of amorphous PPV. Large-area electroluminescent devices were prepared from this polymer. Devices made of an aluminum electrode, PPV as the luminescent layer, and an electron-transporting layer have internal quantum efficiencies of 2 percent, a turn-on voltage of 20 volts, and can carry current densities of 2000 milliamperes per square centimeter. The current density is at least an order of magnitude higher than previously obtained.     

非离子型双元助留体系的湿部化学特性(Ⅰ)PEO/CF体系的絮凝机理和絮凝动力学

本文以聚氧化乙烯/辅助助剂(PEO/CF)体系为例总结了非离子型双元助留体系的絮凝机理和絮凝动力学 目前具代表性的PEO/CF体系的絮凝机理主要包括网络絮凝、诱导缔合聚合物桥联和复合桥联絮凝等几种 絮凝动力学分为平衡絮凝和非平衡絮凝2种过程,絮凝物的断裂模式有伸展型和坚韧型     

水溶性高分子—异氰酸酯复合系胶粘剂的研究

通过正交试验法,研制出特定的聚醋酸乙烯酯母液,丙烯酸酯乳液,丁苯胶乳液,醋酸乙烯－乙烯共聚乳液,以一定的比例混合形成柔性链段的嵌段主体,加入水溶性高分子乳液,构成水溶性高分子－异氰酸酯复合系模拼胶粘剂的主剂,再加上多元醇－异氰权酯预聚体所形成的刚性链段的嵌段主体,混合形成共聚物,经生产性试验,该胶种是非甲醛系胶粘剂,且胶合强工形成快,耐水,耐老化能力强,按研究确定的工艺生产可解决该胶生产的国产化问     

聚丙烯酸葡萄糖酯的合成及在烟草保润中的应用

通过可逆加成断裂链转移(RAFT)聚合制备聚(1,2:5,6-二-氧异亚丙基-D-呋喃葡萄糖丙烯酸酯)(PAlp Glc),再通过水解反应脱除保护基团,最终得到分子量可控、分布较窄的含有葡萄糖侧基的水溶性聚合物。通过1H NMR、GPC等手段表征产品结构,并研究该葡萄糖侧基聚合物添加在烟草中的保润性能。结果表明,该水溶性大分子保润剂在干燥环境下能提升烟丝平衡含水率,防止烟丝干燥失水;在潮湿环境下,能在一定程度上降低烟丝平衡含水率,防止烟丝受潮,是兼具保湿和防潮功能的烟草保润剂。     

Pentaborate Polyanion in the Crystal Structure of Ulexite, NaCaB5O6(OH)6{middle dot}5H2O

Triclinic ulexite crystals contain isolated borate polyanions [B(5)O(6)(OH)(6)](3-) related to the well known pentaborate polyanion [B(5)O(6)(OH)(4)](-) by addition of two hydroxyl groups to two opposite B-O triangles. The isolated ulexite polyanions form the [B(5)O(7)(OH)(4)](n)(3n-) chains previously found in crystals of the related mineral probertite, NaCaB(5)O(7)(OH)(4).3H(2)O.     

Disulfate ion as an intermediate to sulfuric Acid in Acid rain formation

The oxidation of the bisulfite ion by dissolved oxygen to produce sulfate ion involves the formation of a previously undetected intermediate. This intermediate has a fairly strong Raman band at 1090 wave numbers and a weak Raman band at 740 wave numbers, both of which are probably due to sulfur-oxygen stretches. The intermediate is proposed to be the disulfate ion S(2)O(7)(2-), which hydrolyzes into H(+) and either SO(4)(2-) or HSO(4)(2-) with a half-life of about 52 seconds at 25 degrees C.