Ion-conducting polymer

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σ = A exp(-Ea/RT)

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Highly conductive solid polymer electrolytes (SPEs) will make a dramatic impact on the electric and hybrid –electric vehicles (EV / HEV) industry by eliminating hazards related to the use of their liquid counterparts.

Several approaches are being used to improve the ionic conductivity of PEO-based SPEs. A star-shaped borate ester plasticizer was incorporated into the polyethylene oxide polymer matrix in different proportions (Figure 1).

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Figure 2. Ionic conductivities of various SPE formulationsASPEC001ASPEC001- PEO 1.0g + LiTFSI 0.5436 gASPEB001ASPEB001-PEO1.0g + BR3 0.2g + LiTFSI 0.5436 gASPEB002ASPEB002- PEO1.0g + BR3 0.3g + LiTFSI 0.5436 gASPEB003ASPEB003- PEO1.0g + BR3 0.4g + LiTFSI 0.5436 g

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Lithium ion polymer battery

Typical reaction:Anode: carbon-Li(x) - xLi+ - xe−Separator: Li+ conductionCathode: Li(1-x)CoO2 (LiCoO2 or LiMn2O4) + xLi+ + xe−

Polymer electrolyte/separator can be real solid polymer (polyethyleneoxide, PEO) +LiPF6 or other conducting salt +SiO2

Currently commercialized technologies use PVdF (a polymer) gelled with conventional solvents and salts, like EC/DMC/DECetc.

ethylene carbonate, dimethylcarbonate, and diethyl carbonate

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a proton exchange membrane fuel cell

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Proton-conducting polymer

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PLED (polymer light emitting diode)

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Non-linear optics polymer

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Liquid Crystal Display (LCD)

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Liquid crystal

Liquid

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Liquid Crystal Molecules

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Composite materials

Composite materials (or composites) are engineering materials made from two or more components.

One component is often a strong fibre such as fiberglass, quartz, kevlar or carbon fiber that gives the material its tensile strength, while another component (called a matrix) is often a resin such as polyester or epoxy that binds the fibres together, transferring load from broken fibers to unbroken ones and between fibers that are not oriented along lines of tension. Also, unless the matrix chosen is especially flexible, it prevents the fibers from buckling in compression. Some composites use an aggregate instead of, or in addition to, fibers.

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Composite materials

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A Cermet (金屬陶瓷) is a composite material composed of ceramic (cer) and metallic (met) materials. The metal is used as a binder for an oxide, boride, carbide, or alumina. Generally, the metallic elements used are nickel, molybdenum, and cobalt. Depending on the physical structure of the material, cermets can also be metal matrix composites, but cermets are usually less than 20% metal by volume.

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Bio-composites

Apatite is a group of minerals, with the formulaCa5(PO4)3(F,Cl,OH)

Apatite is one of very few minerals which are produced and used by biological systems. Hydroxylapatite is the major component of tooth enamel, and a large component of bonematerial.

Fluorapatite is slightly stronger than hydroxyapatite; thus, fluoridated water, which will allow exchange in the teeth of hydroxyl ions for fluoride ions, slightly strengthens the teeth.

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Hydroxyapatite (HA)

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Hydroxyapatite (HA)

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象牙質

琺瑯質

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造骨細胞

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Biomimetic scheme of bioactive MCM-41 matrix as bone tissue engineering; useful in the preparation of bioceramic implants with previously adsorbed antibiotic and/or antinflammatory drugs, allowing treating locally the infections or inflammatory response of the living tissue surrounding the implantation area.

Solid State Sciences 7 (2005) 233–237Phosphorous-doped MCM-41 as bioactive material

SEM micrographs and EDS analysis of MCM-41 and P-MCM-41 samples before and after soaking in SBF.

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Synthetic Processing of Clay-Based Nanocomposites

• The synthetic route of choice for making a nanocompositedepends on whether the final material is required in the form of an intercalated or exfoliated hybrid (Figure 1). • In the case of an intercalate, the organic component is inserted between the layers of the clay such that the inter-layer spacing is expanded, but the layers still bear a well-defined spatial relationship to each other. • In an exfoliated structure, the layers of the clay have been completely separated and the individual layers are distributed throughout the organic matrix. • A third alternative is dispersion of complete clay particles (tactoids) within the polymer matrix, but this simply represents use of the clay as a conventional filler.

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Figure 1. Formation of nanocomposites from layered silicates and polymers.

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Clays and Clay Modifications

• Common clays are naturally occurring minerals and are thus subject to natural variability in their constitution. • The purity of the clay can affect final nanocompositeproperties. • Many clays are aluminosilicates, which have a sheet-like (layered) structure, and consist of silica SiO4 tetrahedrabonded to alumina AlO6 octahedra in a variety of ways. A 2:1 ratio of the tetrahedra to the octahedra results in smectiteclays, the most common of which is montmorillonite.• The thickness of the layers (platelets) is of the order of 1 nm and aspect ratios are high, typically 100-1500. The clay platelets are truly nanoparticulate.

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Mineral Ideal formulab CECc (meq/100 g)

Dioctahedral minerals Pyrophyllite Al2(Si4O10)(OH)2 0 Montmorillonite Nax(Al2-xMgx)(Si4O10)

(OH)2.zH2O 60 - 120

Beidellite Mx(Al2)(AlxSi4-xO10) (OH)2.zH2O

60 - 120

Nontronite Mx(Fe3+,Al)2(AlxSi4-xO10) (OH)2.zH2O

60 - 120

Trioctahedral minerals

Talc Mg3(Si4O10)(OH)2 0 Hectorite (Na2Ca)x/2(LixMg3-x)

(Si4O10)(OH)2.zH2O 60 - 120

Saponite Cax/2Mg3(AlxSi4-xO10) .zH2O

60 - 120

Sauconite Mx(Zn,Mg)3(AlxSi4-xO10) .zH2O

a: Only major cations are shown. b: x depends on the origin of the mineral; montmorillonites can show a degree of substitution x in the octahedral sheet in the range 0.05- 0.52. Natural samples generally show substitutions in both octahedral and tetrahedral sheets, which renders the real situations more complex. c: Cation-exchange capacity.

• The clays are also characterised by their ion (e.g. cation) exchange capacities, which can vary widely. • One important consequence of the charged nature of the clays isthat they are generally highly hydrophilic species and thereforenaturally incompatible with a wide range of polymer types. • A necessary prerequisite for successful formation of polymer-clay nanocomposites is therefore alteration of the clay polarity to make the clay ‘organophilic’. • An organophilic clay can be produced from a normally hydrophilic clay by ion exchange with an organic cation such as an alkylammonium ion.

For example, Na+ ions in montmorillonite clay can be exchanged for an amino acid such as 12-aminododecanoic acid (ADA):

Na+-CLAY + HO2C-R-NH3+Cl- .HO2C-R-NH3+-CLAY + NaCl45

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• Although the organic pre-treatment adds to the cost of the clay, the clays are nonetheless relatively cheap feedstocks with minimal limitation on supply. • Montmorillonite is the most common type of clay used for nanocomposite formation. • Other types of clay can also be used depending on the precise properties required from the product. These clays include hectorites (magnesiosilicates), which contain very small platelets, and synthetic clays (e.g. hydrotalcite), which can be produced in a very pure form and can carry a positive charge on the platelets, in contrast to the negative charge found in montmorillonites.

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Factors Affecting the Type of Organo-Clay Hybrid Formed• the exchange capacity of the clay• the polarity of the reaction medium• the chemical nature of the interlayer cations

Both thermosets and thermoplastics have been incorporated into nanocomposites, including:· Nylons· Polyolefins, e.g. polypropylene· Polystyrene· Ethylene-vinyl acetate (EVA) copolymer· Epoxy resins· Polyurethanes· Polyimides· Poly(ethylene terephthalate) (PET)

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DOP: dioctyl phthalate, a plasticizer

• PVC shows significantly lower and broader glass transition values with increased plasticizer content. • Effect of clay, however, is less obvious.

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