Syntheses, structures, and characterizations of four new silver(I) sulfonate coordination polymers with neutral ligands

In this paper, four novel silver(I) sulfonate coordination polymers containing neutral ligands, namely, [Ag(2)Ll (biim)(2)]center dot 2H(2)O (1). AgL2(biim) (2), [Ag(HL3)(Pic)(2)]center dot H2O (3), and [Ag-3(L3)(HL3)(4,4'-bipy)(3)(H2O)(2)]center dot 4H(2)O (4), have been synthesized [L1 = 3-carboxy-4-hydroxybenzenesulfonate, L2 = p-aminobenzenesulfonate, H(2)L3 = p-hydroxybenzenesulfonic acid, biim = 1,1'-(1.4-butanediyl)-bis(imidazole), Pic = beta-picoline, 4,4'-bipy = 4,4'-bipyridine]. For compounds 1 and 2, Ag(I) cations are bridged by biim ligands to form a one-dimensional (1D) "zigzag" chain, and L1 and L2 sulfonate ligands are not coordinated to the silver cation. Compound 3 has a dimeric structure in which two silver cations are bridged by two HL3 ligands. For compound 4, L3 ligand coordinates to a silver cation as a monodentate ligand, and Ag(l) cations are bridged by 4,4'-bipy ligands to form a ID chain. Compound 1 contains water dimers, while compound 4 contains water trimers. Compounds 1-3 display room-temperature photoluminescence.

Phenylene vinylene-based electroluminescent polymers with electron transport block in the main chain

We report a new route for the design of soluble phenylene vinylene (PV) based electroluminescent polymers bearing electron-deficient oxadizole (OXD) and triazole (TZ) moieties in the main chains with the aryloxy linkage. Both series of the PV-based polymers were prepared by Wittig reaction. By properly adjusting the OXD and/or TZ content through copolymerization, we can achieve an enhanced balance of hole- and electron injections, such that the device efficiency is significantly improved. Light-emitting diodes fabricated from P1, P2, P3, P4, P5, P6, and P7 with the configuration of Indium-Tin Oxide (ITO)/Poly (styrene sulfonic acid) doped poly (ethylenedioxythiophene) (PEDOT)/polymer/Ca/Al, emit bright green light with the maximum peak around 500 nm. For the device using the optimal polymer (P4) as emitting layer, a maximum brightness of 1300 cd/m(2) at 20 V and a maximum luminance efficiency of 0.325 cd/A can be obtained.

Two new Cu-II coordination polymers: Studies of topological networks and water clusters

Two new Cull coordination polymers, namely [Cu-2(BDC)(2)(L)(4)(H2O)(2)]center dot 14H(2)O (1) and [Cu-1.5(BTC)(L)(1.5)(H2O)(0.5)]center dot 2H(2)O (2), where L = 1,1'-(1,4-butanediyl)bis(imidazole), BDC = 1,4-benzene dicarboxylate, and BTC = 1,3,5-benzenetricarboxylate, have been synthesized at room temperature. Complex 1 exhibits an unusual, square-planar, four-connected 2D (2)(6)4 net, which has been predicated by Wells. Interestingly, three types of water clusters, namely (H2O)(6), (H2O)(8), and (H2O)(10), are observed in the hydrogen-bonded layers constructed by the BDC ligands and water molecules. The BTC anion in compound 2 is coordinated to the Cu" cation as tetradentate ligand to form a (6(6))(2)(4(2)6(4)8(4))(2)(6(4)810) net containing three kinds of nonequivalent points, Thermogravimetric analyses (TGA) and IR spectra for 1 and 2 are also discussed in detail.

Syntheses, crystal structures and magnetic properties of two heterometallic coordination polymers

Two heterometallic chain coordination polymers with the chemical formula {[Cu2Mn2L2(CH3OH)(H2O)] center dot 0.5CH(3)OH center dot 0.5CH(3)CH(2)OH}(n) (1) and {[Cu2Co2L2(H2O)(2)] center dot H2O}(n) (2) have been synthesized and characterized by IR, UV spectroscopy and single-crystal X-ray structural analysis, where H4L = 2-hydroxy-3-[(E)-({2-[(2-hydroxybetizoyl)amino]ethyl}imino)methyl] benzoic acid. Magnetic measurements showed that the two compounds exhibit antiferromagnetic coupling exchange interactions, and satisfactory fittings to the observed magnetic susceptibility data were obtained by assuming a linear four-spin arrangement with two isotropic magnetic exchange interactions.

Dynamic mechanical and thermal properties of plasticized poly(lactic acid)

The blends of low molecular weight triacetin (TAC) and oligomeric poly(1,3-butylene glycol adipate) (PBGA) were used as multiple plasticizers to lubricate poly(lactic acid) (PLA) in this study. The thermal and mechanical properties of plasticized polymers were investigated by means of dynamic mechanical analysis and differential scanning calorimetry. Atomic force microscopy (AFM) was used to analyze the morphologies of the blends. Multiple plasticizers were effective in lowering the glass transition temperature (T-g) and the melting temperature (T-m) of PLA. Moreover, crystallinity of PLA increased with increasing the con-tent of multiple plasticizers. Tensile strength of the blends decreased following the increasing of the plasticizers, but increased in elongation at break. AFM topographic images showed that the multiple plasticizers dispersed between interfibrillar regions. Moreover, the fibrillar crystallite formed the quasicrosslinkings, which is another cause for the increase in elongation at break.

Compatibilization of PP/EPDM blends by grafting acrylic acid to polypropylene and epoxidizing the diene in EPDM

In this article, ethylene-propylene-diene-rubber (EPDM) was epoxidized with an in situ formed performic acid to prepare epoxided EPDM (eEPDM). The eEPDM together with the introduction of PP-g-AA was used to compatibilize PP/EPDM blends in a Haake mixer. FTIR results showed that the EPDM had been epoxidized. The reaction between epoxy groups in the eEPDM and carboxylic acid groups in PP-g-AA had taken place, and PP-g-EPDM copolymers were formed in situ. Torque test results showed that the actual temperature and torque values for the compatibilized blends were higher than that of the uncompatibilized blends. Scanning electron microscopy (SEM) observation showed that the dispersed phase domain size of compatibilized blends and the uncompatibilized blends were 0.5 and 1.5 mu m, respectively. The eEPDM together with the introduction of PP-g-AA could compatibilize PP/EPDM blends effectively. Notched Izod impact tests showed that the formation of PP-g-EPDM copolymer improved the impact strength and yielded a tougher PP blend.

Surface modification of poly(L-lactic acid) to improve its cytocompatibility via assembly of polyelectrolytes and gelatin

Poly(L-lactide) (PLLA) surface was modified via aminolysis by poly(allylamine hydrochloride) (PAH) at high pH and subsequent electrostatic self-assembly of poly(sodium styrenesulfonate) (PSS) and PAH, and the process was monitored by X-ray photoelectron spectroscopy (XPS) and contact angle measurement. These modified PLLAs were then used as charged substrates for further incorporation of gelatin to improve their cytocompatibility. The amphoteric nature of the gelatin was exploited and the gelatin was adsorbed to the negatively charged PLLA/PSS and positively charged PLLA/PAH at pH = 3.4 and 7.4, respectively. XPS and water contact angle data indicated that the gelatin adsorption at pH = 3.4 resulted in much higher surface coverage by gelatin than at pH = 7.4. All the modified PLLA surfaces became more hydrophilic than the virgin PLLA. Chondrocyte culture was used to test the cell attachment, cell morphology and cell viability on the modified PLLA substrates.

Synthesis of poly(epsilon-caprolactone)-b-poly(gamma-benzyl-L-glutamic acid) block copolymer using amino organic calcium catalyst

A biodegradable two block copolymer, poly(epsilon-caprolactone)-b- poly(gamma-benzyl-L-glutamic acid) (PCL-PBLG) was synthesized successfully by ring-opening polymerization of N-carboxyanhydride of gamma-benzyl-L-glutamate (BLG-NCA) with aminophenyl-terminated PCL as a macroinitiator. The aminophenethoxyl-terminated PCL was prepared via hydrogenation of a 4-nitrophenethoxyl-teminated PCL, which was novelly obtained from the polymerization of c-caprolactone (CL) initiated by amino calcium 4-nitrobenzoxide. The structures of the block copolymer and its precursors from the initial step of PCL were confirmed and investigated by H-1 NMR, FT-IR, GPC, and FT-ICRMS analyses and DSC measurements.

Synthesis of novel nitrogen- and sulfur-containing conjugated polymers used as hole-transporting materials for organic light-emitting diodes

Two series of highly soluble novel nitrogen- and sulfur-containing conjugated polymers were synthesized via an acid-induced self-polycondensation of functional monomers with methyl sulfinyl and aromatic groups. The well-defined structures of synthesized polymers were confirmed by their NMR and IR spectra. The highest occupied molecular orbital energy values for these materials, estimated by cyclic voltammetry, showed a broad range of values from about 5.0 to 5.2 eV used as hole-transport layers (HTL) in two-layer light-emitting diodes ITO/HTL/Alq(3)/Mg:Ag [ITO = indium tin oxide, and Alq(3) = tris(8-quinolinato) aluminum]. The typical turn-on voltage of these diodes was about 4-5 V. The maximum brightness of the device was about 3440 cd/m(2) at 20 V. The maximum efficiency was estimated to be 0.15 1m/W at 10 V.

Design, synthesis and characterization of novel nitrogen-and sulfur-containing polymers with well-defined conjugated length

A series of novel nitrogen- and sulfur-containing conjugated polymers with well-defined conjugation length have been synthesized via an acid-induced self-polycondensation of functional monomers with methylsulfinyl groups. Synthesized polymers exhibit good solubility in common solvents, such as CHCl3, THF, DMF, DMSO, and NMP. With increased numbers of aminophenyl groups, these polymers have shown similar electrical properties to polyaniline (PAn), and these are demonstrated by UV-vis spectroscopy and cyclic voltammetry (CV) measurements on the polymers. The conductivity of preliminarily protonic-doped poly[phenylene sulfide-alt-tetrakis(aniline)] (PPSTEA) is up to 10(-1) S cm(-1).

Capacitive detection of glucose using molecularly imprinted polymers

A novel glucose biosensor based on capacitive detection has been developed using molecularly imprinted polymers. The sensitive layer was prepared by electropolymerization of o-phenylenediamine on a gold electrode in the presence of the template (glucose). Cyclic voltammetry and capacitive measurements monitored the process of electropolymerization. Surface uncovered areas were plugged with 1-dodecanethiol to make the layer dense, and the insulating properties of the layer were studied in the presence of redox couples. The template molecules and the nonbound thiol were removed from the modified electrode surface by washing with distilled water. A capacitance decrease could be obtained after injection of glucose. The electrode constructed similarly but with ascorbic acid or fructose only showed a small response compared with glucose. The stability and reproducibility of the biosensor were also investigated. (C) 2001 Elsevier Science B.V. All rights reserved.

Nitrogen- and sulfur-containing conjugated polymers as the hole-transporting materials

A series of novel nitrogen- and sulfur-containing conjugated polymers have been synthesized via an acid-induced self polycondensation of functional monomers with methyl sulfinyl group. They exhibit good solubility in common solvents, such as CHCl3, THF, DMF, DMSO, et al; and thus show excellent film-forming properties. They are used as hole-transport layer (HTL) in two-layer light-emitting diodes (ITO/polymer/Alq3/Mg:Ag). The typical turn-on voltage of these diodes is about 4 similar to 5V. The maximum brightness is about 3440cd/m(2) at 20 V. The maximum efficiency is estimated to be 0.15 Im/W at 10V.

Synthesis and characterization of chiral smectic side-chain liquid crystalline polysiloxanes and ionomers containing sulfonic acid groups

The synthesis of new chiral smectic A (S-A) side-chain liquid crystalline polysiloxanes (LCPs) and ionomers (LCIs) containing 4-allyloxy-benzoyl-4-(S-2-ethylhexanoyl) p-benzenediol his ate (ABB) as mesogenic units and 4-[[4-(2-propenyloxy)phenyl] azo]benzensulfonic acid (AABS) as nonmesogenic units is presented. The chemical structures of the monomers and polymers are confirmed by FTIR spectroscopy or H-1-NMR. Differential scanning calorimetry (DSC), optical polarizing microscopy, and X-ray diffraction measurements reveal that all the polymers P-I-P-IV and ionomers P-V-P-VI exhibit S-A texture. The results seem to demonstrate that the tendency toward the S-A-phase region increases with increasing sulfonic acid concentration, and the thermal stability of the S-A phase is determined by the flexibility of the polymer backbones and the interactions of sulfonic acid groups. (C) 2001 John Wiley & Sons, Inc.

Syntheses and properties of thermotropic copolyesters of p-hydroxybenzoic acid

Two series of thermotropic copolyesters of p-hydroxybenzoic acid (HBA) were synthesized by direct thermal polycondensation. One comprised aromatic copolyesters from HBA, terephthalic acid, bis(4-hydroxyphenyl) ketone (BHP) and resorcinol. The other comprised semi-aromatic copolyesters from HBA, terephthalic acid, BHP and alpha,-diols with carbon atom number of 4, 6, 8, 10. The properties of the two series were characterized by polarized light microscopy, differential scanning calorimetry and wide angle X-ray diffraction. Most of the resulting copolyesters could form a nematic phase over a wide temperature range above their melting points. The effects of Variation in composition and monomer structure on the properties of copolyesters were discussed. (C) 2001 Elsevier Science Ltd. All rights reserved.

Studies on blends of LLDPE and polar polymers compatibilized by a random copolymer

Compatibilization of blends of Linear low-density polyethylene (LLDPE)-poly(methyl methacrylate) (PMMA) and LLDPE-copolymer of methyl methacrylate (MMA) and 4-vinylpyridine (poly(MMA-co-4VP) with poly(ethylene-co-methacrylic acid) (EMAA) have been studied. Mechanical properties of the LLDPE-PMMA blends increase upon addition of EMAA. In order to further improve interfacial adhesion of LLDPE and PMMA, 4-vinyl pyridine units are introduced into PMMA chains, or poly(MMA-co-4VP) is used as the polar polymer. In LLDPE-poly(MMA-co-4VP)-EMAA blends, interaction of MAA in EMAA with 4VP of poly(MMA-co-4VP) causes a band shift in the infrared (IR) spectra. Chemical shifts of N-1s binding energy in X-ray photoelectronic spectroscopy (XPS) experiments indicate a transfer of proton from MAA to 4VP. Scanning electron microscopy (SEM) pictures show that the morphology of the blends were improved upon addition of EMAA. Nonradiative energy transfer (NRET) fluorescence results attest that there exists interdiffusion of chromophore-labeled LLDPE chains and chromophore-labeled poly(MMA-co-4VP) chains in the interface. Based on experimental results, the mechanism of compatibilization is studied in detail. Compatibilization is realized through the interaction between MAA in EMAA with 4VP in poly(MMA-co-4VP). (C) 1999 John Wiley & Sons, Inc.