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1.
A microphase‐separated, amphiphilic graft copolymer consisting of a poly (vinyl chloride) (PVC) backbone and poly(oxyethylene methacrylate) (POEM) side chains, (PVC‐g‐POEM at 62:38 wt %) was synthesized via atom transfer radical polymerization (ATRP). Nuclear magnetic resonance (1H NMR), FTIR spectroscopy, and transmission electron microscopy (TEM) clearly revealed that the “grafting from” method using ATRP was successful and that the graft copolymer molecularly self‐assembled into discrete nanophase domains of continuous PVC and isolated POEM regions. The self‐assembled graft copolymer film was used to template the growth of silver nanoparticles in solid state by introducing a AgCF3SO3 precursor and a UV irradiation process. The in situ formation of silver nanoparticles in the graft copolymer template film was confirmed by TEM, UV–visible spectroscopy, and wide angle X‐ray scattering. FTIR spectroscopy and X‐ray photoelectron spectroscopy also demonstrated the selective incorporation and in situ formation of silver nanoparticles within the hydrophilic POEM domains, presumably due to strong interactions between the silver and the ether oxygen in POEM. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3911–3918, 2008  相似文献   

2.
Silver nanoparticles were prepared by UV irradiation from silver salts, such as AgBF4 or AgNO3, when dissolved in an amphiphilic film of poly((oxyethylene)9 methacrylate)‐graft‐poly((dimethyl siloxane)n methacrylate), POEM‐g‐mPDMS. The in situ formation of silver nanoparticles in the graft copolymer film was confirmed by transmission electron microscopy (TEM), UV‐visible spectroscopy, and wide angle X‐ray scattering (WAXS). The results demonstrated that the use of AgBF4 yielded silver nanoparticles with a smaller size (~5 nm) and narrower particle distribution when compared with AgNO3. The formation of silver nanoparticles was explained in terms of the interaction strength of the silver ions with the ether oxygens of POEM, as revealed by differential scanning calorimetry (DSC) and X‐ray photoelectron spectroscopy (XPS). It was thus concluded that a stronger interaction of silver ions with the ether oxygens results in a more stable formation of silver nanoparticles, which produces uniform and small‐sized nanoparticles. DSC and small angle X‐ray scattering (SAXS) data also showed the selective incorporation and in situ reduction of the silver ions within the hydrophilic POEM domains. Excellent mechanical properties of the nanocomposite films (3–5 × 105 dyn/cm2) were observed, mostly because of the confinement of silver nanoparticles in the POEM chains as well as interfaces created by the microphase separation of the graft copolymer film. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1283–1290, 2007  相似文献   

3.
An amphiphilic comb‐like copolymer consisting of a poly(vinyl chloride) (PVC) backbone and poly((oxyethylene)9 methacrylate) (POEM) side chains, PVC‐graft‐POEM was synthesized via atom transfer radical polymerization. This comb copolymer was complexed with LiCF3SO3 to form a solid polymer electrolyte. FTIR and FT‐Raman spectroscopy indicate that lithium salts are dissolved in the ion conducting POEM domains of microphase‐separated graft copolymer up to 10 wt % of salt concentration. Microphase‐separated structure of the materials and the selective interaction of lithium ions with POEM domains were revealed by transmission electron microscopy, wide angle X‐ray scattering, and differential scanning calorimetry. The maximum ionic conductivity of 4.4 × 10?5 S/cm at room temperature was achieved at 10 wt % of salt concentration, above which salts are present as less mobile species such as ion pairs and higher order ionic aggregates, as characterized by FT‐Raman spectroscopy. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1443–1451, 2009  相似文献   

4.
In this study, poly(vinylidene fluoride‐co‐chlorotrifluoroethylene)‐graft‐poly(oxyethylene methacrylate), P(VDF‐co‐CTFE)‐g‐POEM, an amphiphilic comb copolymer with hydrophobic P(VDF‐co‐CTFE) backbone and hydrophilic POEM side chains at 73:27 wt % was synthesized. The POEM side chains were grafted from the P(VDF‐co‐CTFE) mainchain backbone via atom transfer radical polymerization (ATRP) using direct initiation of the chlorine atoms in CTFE units. Synthesis of microphase‐separated P(VDF‐co‐CTFE)‐g‐POEM comb copolymer was successful, as confirmed by nuclear magnetic resonance (1H NMR), FTIR spectroscopy, and transmission electron microscopy (TEM). Nanocomposite films were prepared using the comb copolymer as a template film and the in situ reduction of AgCF3SO3 precursor to silver nanoparticles under UV irradiation. Silver nanoparticles with 4–8 nm in average size were in situ created in the solid state template film, as revealed by TEM, UV–visible spectroscopy, and wide angle X‐ray scattering (WAXS). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) presented the selective incorporation and the in situ growth of silver nanoparticles within the hydrophilic POEM domains of microphase‐separated comb copolymer film. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 702–709, 2008  相似文献   

5.
Interactions of cation/anion and cation/polymer in poly(N‐vinyl pyrrolidone) (PVP):silver triflate (AgCF3SO3) electrolytes with different weight‐average molecular weights (Mw's) of 1 × 106 (1 M), 3.6 × 105 (360 K), 4 × 104 (40 K), and 1 × 104 (10 K) have been studied with IR and Raman spectroscopies. According to the change of the C?O peak, coordination of silver ions by C?O in a low Mw (10 or 40 K) PVP matrix tend to be always thermodynamically favorable than high Mw (1 M or 360 K) PVP, demonstrating that the polymer matrix of low Mw dissolves silver salts more effectively. In addition, silver cations interact with both larger SO and smaller CF3 to form ion pairs, and the former interaction is stronger than the latter in a monomer or low Mw polymer matrix (40 K, 10 K), as demonstrated by theoretical ab initio calculation or experimental spectroscopy, respectively. However, CF3 interacts more favorably with silver cation than SO in high Mw (1 M and 360 K) PVP, which is ascribed to the steric effect of the bulky SO anion by highly entangled polymer chains. Despite the superior dissolving property of the low Mw polymer matrix, the membranes consisting of low Mw PVP and AgCF3SO3 exhibited poor separation performance for propylene/propane mixtures in comparison with those of high Mw, presumably because of the poor mechanical property for membrane formation in low Mw PVP. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1813–1820, 2002  相似文献   

6.
Summary: Results obtained recently on polymer electrolytes poly(ethylene oxide) (PEO)/LiCF3SO3 and poly(2-ethyl-2-oxazoline) (POZ)/AgCF3SO3 by a combination of solid-state 13C and 1H NMR spectroscopy and DFT quantum-chemical calculations are discussed. Essentially the same local structure was found for the amorphous and crystalline phases of semicrystalline PEO/LiCF3SO3 polymer electrolyte. The amorphous POZ/AgCF3SO3 complex has a defined stoichiometry with two POZ monomeric units per one AgCF3SO3. A close contact between the metal salt and polymer was determined for both investigated systems from the Lee-Goldburg cross-polarization 1H → 13C dynamics.  相似文献   

7.
When polymer–silver salt complex membranes were exposed to UV irradiation, the separation performances of both the permeance and selectivity for propylene–propane decreased, which was primarily attributed to the reduction of the silver ions in the membranes to silver nanoparticles. Here, the effect of the polymer matrix on the formation of silver nanoparticles in the polymer–silver salt complex membranes was investigated. This effect was assessed for the complexes of two kinds of silver salts (AgBF4 and AgCF3SO3) with several polymeric ligands containing three different carbonyl groups, including poly(vinyl pyrrolidone) (PVP) with an amide group, poly(vinyl methyl ketone) (PVMK) with a ketone group, and poly(methyl methacrylate) (PMMA) with an ester group. UV–vis spectra and transmission electron microscopy (TEM) images clearly indicated that the reduction rate of the silver ions has the following order in the various polymer matrices: PVP > PVMK > PMMA, whereas the size and the distribution of the nanoparticles exhibited the reverse order. The tendency to form silver nanoparticles was explained in terms of the differences between the comparative strengths of the interactions of the silver ions with the different carbonyl oxygens in the matrices, as well as that of the silver ions with counteranions, which was characterized by X‐ray photoelectron spectroscopy (XPS) and FT‐Raman spectroscopy. It was concluded that when the concentration of free silver ions was low due to weak polymer–silver ion and strong silver ion–anion interactions, as found with PMMA, the reduction rate of silver ions to silver nanoparticles was slow. Therefore, the PMMA–silver complex membranes were less sensitive to decreases in separation performance upon UV irradiation than compared to the PVP membranes. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1168–1178, 2006  相似文献   

8.
A novel type of random copolymer comprised of a polymerized ionic liquid, poly(1-((4-ethenylphenyl)methyl)-3-butyl-imidazolium iodide) (PEBII), and amorphous rubbery poly(oxyethylene methacrylate) (POEM) was synthesized and employed as a solid electrolyte in an I2-free dye-sensitized solar cell (DSSC). The copolymer electrolytes deeply infiltrated into the nanopores of mesoporous TiO2 films, resulting in improved interfacial contact of electrode/electrolyte. The glass transition temperature (T g) of the PEBII–POEM (?23 °C) was lower than that of PEBII homopolymer (?4 °C), indicating greater chain flexibility in the former. However, the DSSC efficiency of PEBII–POEM (4.5 % at 100 mW/cm2) was lower than that of PEBII (5.9 %), indicating that ion concentration is more important than chain flexibility. Interestingly, upon the introduction of ionic liquid, i.e., 1-methyl-3 propylimidazolium iodide, the efficiency of PEBII remained almost constant (5.8 %), whereas that of PEBII–POEM was significantly improved up to 7.0 % due to increased I? ion concentration, which is one of the highest values for I2-free DSSCs.  相似文献   

9.
Based on the fact that the flexibility of the polymer backbone will affect the ion transport and sometimes enhance the ionic conductivity, copolymer electrolytes of 1,2,4,5-benzene-tetracarboxylic dianhydride (PMDA), 4-aminophenyl ether (ODA), and aminopropyldimethyl-terminated polydimethylsiloxane (PSX), with or without doping of lithium triflate, have been prepared and investigated by infrared spectroscopy and electrical conductivity measurements. The PSX was found to be incorporated into PMDA-ODA polyimide to form block copolymers, and the best conductivity (10-7 s/cm at 300°C) is observed in the lithium triflate-doped PMDA-ODA-PSX copolymer with a composition of 4PMDA: 3DA: 0.6PSX: 2LiCF3SO3. This conductivity is about 100 times better than the result of the lithium-doped PMDA, ODA, and 2,5-diaminobenzene sulfonic acid (DABSA) copolymer (4PMDA: 3DA:1DABSA:1LiCF3SO3) recently reported by this group. © 1994 John Wiley & Sons, Inc.  相似文献   

10.
Hexanuclear thiolato‐bridged arene ruthenium metalla‐prisms of the general formula [(p‐cymene)6Ru6(SR)6(tpt)2]6+ (R=CH2Ph, CH2C6H4ptBu, CH2CH2Ph; tpt=2,4,6‐tris(4‐pyridyl)‐1,3,5‐triazine), obtained from the dinuclear precursors [(p‐cymene)2Ru2(SR)2Cl2], AgCF3SO3 and tpt, have been isolated and fully characterised as triflate salts. The metalla‐prisms are highly cytotoxic against human ovarian cancer cells, especially towards the cisplatin‐resistant cell line A2780cisR (IC50 <0.25 μM ).  相似文献   

11.
The interaction of Fe2O3 nanoparticles emphasized between poly(propylene glycol) (PPG 4000) and silver triflate (AgCF3SO3) on the conformal changes of coordination sites and the electrochemical properties have been investigated. On the influence of Fe2O3 nanoparticles distribution, the interactions between the ether oxygen in C–O–C of the polymer chain with Ag+ ion as a result of bond strength of the C–O–C stretching vibration, the end group effect has been examined by Fourier transform infrared (FT-IR) spectroscopy. The formation of transient cross-links between polymer chains and filler particles appears to be a characteristic change in the glass transition temperature (T g) and enhance the effective number of cations as well. The strength of ion–polymer interactions was revealed by the transport of ions, t Ag+, and found to be in the range of 0.42–0.50, and the ionic conductivity was ascertained by complex impedance analysis with a maximum of 9.2?×?10?4 S cm?1 at 298 K with a corresponding concentration of 10 wt% Fe2O3 nanoparticles. The temperature dependence of conductivity has been examined based on the Vogel–Tammann–Fulcher (VTF) equation, thereby suggesting the segmental chain motion and free volume changes. From the impedance data, both the dielectric and modulus behaviours have been revealed and both were well correlated as a function of frequency.  相似文献   

12.
Poly[aniline(AN)‐co‐5‐sulfo‐2‐anisidine(SA)] nanograins with rough and porous structure demonstrate ultrastrong adsorption and highly efficient recovery of silver ions. The effects of five key factors—AN/SA ratio, AgI concentration, sorption time, ultrasonic treatment, and coexisting ions—on AgI adsorbability were optimized, and AN/SA (50/50) copolymer nanograins were found to exhibit much stronger AgI adsorption than polyaniline and all other reported sorbents. The maximal AgI sorption capacity of up to 2034 mg g?1 (18.86 mmol g?1) is the highest thus far and also much higher than the maximal Hg‐ion sorption capacity (10.28 mmol g?1). Especially at ≤2 mM AgI, the nanosorbents exhibit ≥99.98 % adsorptivity, and thus achieve almost complete AgI sorption. The sorption fits the Langmuir isotherm well and follows pseudo‐second‐order kinetics. Studies by IR, UV/Vis, X‐ray diffraction, polarizing microscopy, centrifugation, thermogravimetry, and conductivity techniques showed that AgI sorption occurs by a redox mechanism mainly involving reduction of AgI to separable silver nanocrystals, chelation between AgI and ? NH? /? N?/? NH2/ ? SO3H/? OCH3, and ion exchange between AgI and H+ on ? SO3?H+. Competitive sorption of AgI with coexisting Hg, Pb, Cu, Fe, Al, K, and Na ions was systematically investigated. In particular, the copolymer nanoparticles bearing many functional groups on their rough and porous surface can be directly used to recover and separate precious silver nanocrystals from practical AgI wastewaters containing Fe, Al, K, and Na ions from Kodak Studio. The nanograins have great application potential in the noble metals industry, resource reuse, wastewater treatment, and functional hybrid nanocomposites.  相似文献   

13.
The preparation of a series of crown ether ligated alkali metal (M=K, Rb, Cs) germyl derivatives M(crown ether)nGeH3 through the hydrolysis of the respective tris(trimethylsilyl)germanides is reported. Depending on the alkali metal and the crown ether diameter, the hydrides display either contact molecules or separated ions in the solid state, providing a unique structural insight into the geometry of the obscure GeH3? ion. Germyl derivatives displaying M? Ge bonds in the solid state are of the general formula [M([18]crown‐6)(thf)GeH3] with M=K ( 1 ) and M=Rb ( 4 ). The compounds display an unexpected geometry with two of the GeH3 hydrogen atoms closely approaching the metal center, resulting in a partially inverted structure. Interestingly, the lone pair at germanium is not pointed towards the alkali metal, rather two of the three hydrides are approaching the alkali metal center to display M? H interactions. Separated ions display alkali metal cations bound to two crown ethers in a sandwich‐type arrangement and non‐coordinated GeH3? ions to afford complexes of the type [M(crown ether)2][GeH3] with M=K, crown ether=[15]crown‐5 ( 2 ); M=K, crown ether=[12]crown‐4 ( 3 ); and M=Cs, crown ether=[18]crown‐6 ( 5 ). The highly reactive germyl derivatives were characterized by using X‐ray crystallography, 1H and 13C NMR, and IR spectroscopy. Density functional theory (DFT) and second‐order Møller–Plesset perturbation theory (MP2) calculations were performed to analyze the geometry of the GeH3? ion in the contact molecules 1 and 4 .  相似文献   

14.
Eight new silver(I) double salts: AgL1·2AgCF3COO (1), AgL1·3AgNO3 (2), 2AgL2·5AgCF3COO·2CH3CN·H2O (3), 4AgL3·6AgCF3COO·5CH3CN (4), 4AgL4·6AgCF3COO·5CH3CN (5), 2AgL5·4AgCF3COO·NC(CH2)4CN (6), 2AgL5·4AgCF3COO·2CH3CN (7) and AgL6·2CF2(CF2COOAg)2·2CH3CN (8) (L1 = 4-iodophenylethynide; L2 = 3,4-dichlorophenylethynide; L3 = 3-chlorophenylethynide; L4 = 3-bromophenylethynide; L5 = 2-chlorophenylethynide; L6 = 2-fluorophenylethynide) have been synthesised and characterized by X-ray crystallography. All compounds contain the silver–halophenylethynide supramolecular synthon RX−CCAgn (n = 4, 5). In particular, the three-dimensional supramolecular structures in 1 and 2 are stabilized by strong AgI interactions, while that in 3 is consolidated by both AgCl and van der Waals type FCl interactions. In isomorphous compounds 4 and 5, the presence of respective FCl or FBr contact contributes to the stability of the network. The silver aggregates in 6, 7 and 8 are stabilized by AgCl or AgF interactions between the ortho-halo substituent and the Agn basket.  相似文献   

15.
The oxidation of SO2 by nonmetal oxoanions in the gas phase is investigated in an experimental and theoretical study of the structure of the species involved and the reaction kinetics and mechanism. SO3, SO3.? and SO4.? are efficiently produced by reaction of OnXO? anions (X=Cl, Br, and I; n=0 and 1) with SO2; XO? ions mainly react to give SO3 by oxygen‐atom transfer, whereas OXO? ions mainly give SO3.? by oxygen‐anion transfer. On descending the halogen group from chlorine to iodine, the SO3/SO3.? ratio decreases and increases for reactions involving XO? and OXO? anions, respectively, whereas the formation of SO4.? is particularly significant with OIO?. Kinetic factors play a major role in the reactions of OnXO?, depending on the halogen atom and its oxidation state.  相似文献   

16.
The gel polymer electrolytes composed of ionic liquid, 1‐butyl‐3‐methylimidazolium tetrafluoroborate (BMImBF4) and the copolymer of acrylonitrile (AN), methyl methacrylate (MMA), poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) are synthesized and characterized by FT‐IR spectra, TGA, DSC, and AC impedance measurements. IR spectra show that there is an interaction between PEO side chains of the copolymer and imidazolium cations. TGA measurements indicate that the gel polymer electrolytes are stable until 120°C. By using the equivalent circuit proposed, the experimental data and the simulated data fit very well. The bulk resistance Rb is found to decrease with the increase in BMImBF4 content. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

17.
The polymer electrolytes composed of poly(acrylonitrile‐co‐lithium methacrylate) [P(AN‐co‐LiMA)], ethylene carbonate (EC), and LiClO4 salts have been prepared. The ion groups in the P(AN‐co‐LiMA) were found to prevent EC from crystallization through their ion–dipole interactions with the polar groups in the EC. This suppression of the EC crystallization could lead to the enhancement of the ion conductivity at subambient temperature. The polymer electrolytes based on the PAN ionomer with 4 mol % ion content exhibited ion conductivities of 2.4 × 10−4 S/cm at −10°C and 1.9 × 10−3 S/cm at 25°C by simply using EC as a plasticizer. In the polymer electrolytes based on the PAN ionomer, ion motions seemed to be coupled with the segmental motions of the polymer chain due to the presence of the ion–dipole interaction between the ion groups in the ionomer and the polar groups in the EC, while the ion transport in the PAN‐based polymer electrolytes was similar to that of the liquid electrolytes. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 247–252, 1999  相似文献   

18.
The reactions of 2,11-diaza-difluoro-m-[3.3]-cyclophane with 1,3-bis(bromomethyl)-2-fluorobenzene or 2,6-bis(bromomethyl)-pyridine lead in one step to the respective 3 + 3-addition products 4 (yield 11%) and 5 (yield 27%), both of which are 48-membered macrocycles with nine or six potential CF-donor units. The nonafluoro ligand 4 appears not to form stable aggregates with alkali metal ions, while 5 gives a complex with two silver ions, which both are located on the inner periphery of the macrocyclic cavity. The coordination sphere of the two silver ions consists of three nitrogen atoms in a distorted trigonal-planar (Y-shape) environment as evidenced by an X-ray crystal structure. One of the Ag+ displays a short contact to an oxygen atom of the CF3SO3 counter ion, leading to a trigonal-pyramidal N3O-environment.  相似文献   

19.
Red single crystals of Pt2(HSO4)2(SO4)2 were obtained by the reaction of elemental platinum with conc. sulfuric acid at 350 °C in sealed glass ampoules. The crystal structure (monoclinic, P21/c, Z = 2, a = 868.6(2), b = 826.2(1), c = 921.8(2) pm, β=116.32(1)°, Rall = 0.0348) shows dumbbell shaped Pt26+ cations which are coordinated by four SO42— and two HSO4 ions. Each of the sulfate ions is attached to another Pt26+ ion yielding layers according to equation/tex2gif-stack-1.gif[Pt2(SO4)4/2(HSO4)2/1]. The layers are connected by hydrogen bonds with the OH group of the hydrogensulfate ion as donor and the non‐bonding oxygen atom of the sulfate ion as acceptor.  相似文献   

20.
A vinyl ether bearing a carbonate side group (2‐oxo‐1,3‐dioxolan‐4‐yl‐methyl vinyl ether, GCVE) was synthesized and copolymerized with various commercially available fluoroolefins [chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), and perfluoromethyl vinyl ether (PMVE)] by radical copolymerization initiated by tert‐butyl peroxypivalate. Although HFP, PMVE, and vinyl ether do not homopolymerize under radical conditions, they copolymerized easily yielding alternating poly(GCVE‐alt‐F‐alkene) copolymers. These alternating structures were confirmed by elemental analysis as well as 1H, 19F, and 13C NMR spectroscopy. All copolymers were obtained in good yield (73–85%), with molecular weights ranging from 3900 to 4600 g mol?1 and polydispersities below 2.0. Their thermogravimetric analyses under air showed decomposition temperatures at 10% weight loss (Td,10%) in the 284–330°C range. The HFP‐based copolymer exhibited a better thermal stability than those based on CTFE and PMVE. The glass transition temperatures were in the 15–65°C range. These original copolymers may find potential interest as polymer electrolytes in lithium ions batteries. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012  相似文献   

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