bluuebunny/crossref_metadata_2025_split huggingface dataset:
High‐quality surface remeshing using harmonic maps
Authors: Remacle J.‐F. , Geuzaine C. , Compère G. , Marchandise E. 
Published: February 2010

AbstractIn this paper, we present an efficient and robust technique for surface remeshing based on harmonic maps. We show how to ensure a one‐to‐one mapping for the discrete harmonic map and introduce a cubic representation of the geometry based on curved PN triangles. Topological and geometrical limitations of harmonic maps are also put to the fore and discussed. We show that, with the proposed approach, we are able to recover high quality meshes from both low input STL triangulations and complex surfaces defined by many CAD patches. The overall procedure is implemented in the open‐source mesh generator Gmsh. Copyright © 2010 John Wiley & Sons, Ltd.
A multi‐scale spectral stochastic method for homogenization of multi‐phase periodic composites with random material properties
Authors: Tootkaboni M. , Graham‐Brady L. 
Published: February 2010

AbstractIn this work a spectral stochastic computational scheme is proposed that links the global properties of multi‐phase periodic composites to the geometry and random material properties of their microstructural components. To propagate the uncertainties associated with the material properties to the microstructural response the scheme benefits from a combination of homogenization theory built into a finite element framework and the spectral representation of uncertainty based on Hermite Chaos where a probabilistic characterization of the solutions to a set of local problems defined on the period cell is first sought. A full stochastic description of the global (effective) properties is then obtained by averaging the solutions to the forgoing set of local problems over the unit cell. A representative subset of results is compared with the results obtained using Monte Carlo simulation to demonstrate the accuracy of the proposed procedure. Copyright © 2010 John Wiley & Sons, Ltd.
Eigensolution of augmented graph products using shifted inverse iteration method
Authors: Kaveh A. , Fazli H. 
Published: February 2010

AbstractTwo important matrices associated with graphs are adjacency and Laplacian matrices. In this paper efficient methods are presented for eigensolution of graph products augmented by other graphs. For augmentations that do not destroy the symmetry of the graph products, a method is proposed for decomposition of matrices resulting in considerable simplification of their eigensolution. For graphs composed of two non‐overlapping graph products joined through a small number of link members, a method based on shifted inverse iteration is proposed which utilizes all eigenvalues and eigenvectors of each individual graph products. Owing to the availability of fast methods for eigensolution of graph products, this method simplifies the eigensolution of a variety of graph models and proves to be very efficient in determining the few smallest eigenpairs of these models with high levels of accuracy. Copyright © 2010 John Wiley & Sons, Ltd.
Synthesis of bipolar charge transporting block copolymers and characterization for organic light‐emitting diode
Authors: Tsuchiya Kousuke , Kasuga Hidemasa , Kawakami Akira , Taka Hideo , Kita Hiroshi , Ogino Kenji 
Published: February 2010

AbstractA series of hole and electron transporting random and block copolymers consisting of triphenylamine moiety as a hole transporting unit and oxadiazole moiety as an electron transporting unit have been prepared via a nitroxide mediated radical polymerization. Oxadiazole monomers with t‐butyl or trifluoromethyl groups, 2 and 7, respectively, were used for copolymerization. Photoluminescent measurements of polymers revealed that the formation of the exciplex between triphenylamine and oxadiazole units tends to occur in the order of random copolymers, block copolymers, and polymer blends, implying phase‐separated morphologies in block or blend systems. The polymers were applied for OLED devices, and we found that the morphology in the polymer layer critically affected device performance. The block copolymer comprising hole and electron transporting units with the composition of 14/86 showed the highest external quantum efficiency over 10%. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1461–1468, 2010
Electrochromic material containing unsymmetrical substituted N,N,N′,N′‐tetraaryl‐1,4‐phenylenediamine: Synthesis and their optical, electrochemical, and electrochromic properties
Authors: Wu Han‐Yu , Wang Kun‐Li , Liaw Der‐Jang , Lee Kueir‐Rarn , Lai Juin‐Yih 
Published: February 2010

AbstractA novel dibromo compound containing unsymmetrical substituted bi‐triarylamine was synthesized. A conjugated polymer was prepared via the Suzuki coupling from the newly prepared dibromo compound and 9,9‐dioctylfluorene‐2,7‐bis(trimethyleneboronate). The glass transition temperature (Tg) of the conjugated polymer was 140 °C, 10% weight‐loss temperatures (Td10) in nitrogen was 458 °C, and char yield at 800 °C in nitrogen higher than 64%. Cyclic voltammogram of the polymer film cast onto an indium‐tin oxide (ITO)‐coated glass substrate exhibited two reversible oxidation redox couples at 0.70 and 1.10 V versus Ag/Ag+ in acetonitrile solution. The polymer films revealed excellent stability of electrochromic characteristics, with a color change from yellow green of the neutral form to the dark green and blue of oxidized forms at applied potentials ranging from 0 to 1.3 V. The color switching time and bleaching time were 4.25 and 7.22 s for 860 nm and 5.51 s and 6.48 s for 560 nm. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1469–1476, 2010
Synthesis of MWCNTs‐core/thiophene polymer‐sheath composite nanocables by a cationic surfactant‐assisted chemical oxidative polymerization and their structural properties
Authors: Reddy Kakarla Raghava , Jeong Han Mo , Lee Youngil , Raghu Anjanapura Venkataramanaiah 
Published: February 2010

AbstractMulti‐walled carbon nanotubes (MWCNTs)‐core/thiophene polymer‐sheath composite nanocables were synthesized by chemical oxidative polymerization of 3,4‐ethylenedioxythiophene (EDOT) with oxidant (FeCl3) in the presence of cationic surfactant, deceyltrimethyl ammonium bromide (DTAB). In the polymerization process, DTAB surfactant molecules were adsorbed on the surface of MWCNTs and forms MWCNTs‐DTAB soft template. Upon the addition of EDOT and oxidant, the polymerization take place on the surface of MWCNTs and PEDOT is gradually deposited on the surface of MWCNTs. The resulting MWCNTs‐PEDOT nanocomposites have the nanocable structure. Nanocomposites were characterized by HRTEM, FE‐SEM, XRD, XPS, TGA, FTIR and PL, respectively. The π‐π interactions between PEDOT and MWCNTs enhancing the thermal and electrical properties of the nanocomposites with loading of MWCNTs. The temperature dependence conductivity measurements show that the conductivity of the nanocomposite decrease with a decrease of temperature, and conductivity‐temperature relationship is well fit by the quasi‐one dimensional variable range hopping mode. The mechanism for the formation of composite nanocables was explained on the basis of self‐ assembly of micelles. The reported self‐assembly strategy for the synthesis of PEDOT‐coated MWCNTs in micellar medium is a rapid, versatile, potentially scalable, stable, and making it useful for further exploitation in a varies types of applications. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1477–1484, 2010
A new strategy for the synthesis of methacrylate end‐functionalized macromonomers by ATRP
Authors: Piogé Sandie , Fontaine Laurent , Soutif Jean‐Claude , Nicol Erwan , Pascual Sagrario 
Published: February 2010

AbstractThe influence of the polymerization temperature, the [CuBr]0/[PMDETA]0 ratio, and the monomer conversion on the chain‐end functionality of poly(ethyl acrylate)s (PEAs) was studied during the atom transfer radical polymerization (ATRP) of ethyl acrylate (EA) using CuBr/N,N,N′,N′,N″‐pentamethyldiethylenetriamine (PMDETA) as a catalyst system and ethyl‐2‐bromo‐2‐methylpropionate (EBiB) as an initiator. The presence of bromine chain‐end of PEA was checked by MALDI‐TOF spectrometry and by chain‐extension reaction. It was shown that ATRP of EA performed with [EA]0/[EBiB]0/[CuBr]0/[PMDETA]0 ratios of 25/1/0.5/0.5 in toluene at 50 °C allows to obtain a quantitative functionality of halide end‐groups of PEA up to 66% monomer conversion. Well‐defined poly(ethylene oxide)‐b‐poly(ethyl acrylate) PEO‐b‐PEA bearing bromide chain‐ends were obtained by the ATRP of EA using PEO‐Br as a macroinitiator under previous experimental conditions. A more detailed study of PEO‐b‐PEA block copolymers synthesis was previously published (Piogé et al., Macromolecules 2009, 42, 4262–4272). These end‐groups were transformed into methacrylate end‐groups by a two‐step pathway. An original approach to generate hydroxyl end‐groups was based on the nucleophilic substitution of the halogen end‐groups using different mercaptoalcohols. Using 6‐mercaptohexan‐1‐ol, a quantitative functionalization was observed. In a second step, hydroxyl groups were esterified quantitatively with methacryloyl chloride, and the resulting methacrylate end‐functionalized PEO‐b‐PEA macromonomers have well‐defined molecular weights and low polydispersities. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1526–1537, 2010
The nature of Cu(II) species in ATRP: New insights via EPR
Authors: Caretti Ignacio , Dervaux Bart , Du Prez Filip E. , Van Doorslaer Sabine 
Published: February 2010

AbstractIdentification of the paramagnetic species present in the Cu(I)Br‐catalyzed atom transfer radical polymerization (ATRP) of a model monomer (isobornyl acrylate) has been carried out by electron paramagnetic resonance (EPR) in the continuous wave mode at 90 K. Up to five different species—four copper‐based species and one organic radical—were detected with this technique. The EPR parameters of the copper‐based species are found to differ strongly, and originate from diverse isolated Cu(II) complexes, as well as dipolarly interacting and even exchange‐coupled Cu(II) species. The work highlights the complexity of the copper‐based EPR signal observed in copper‐mediated ATRP reactions. Analysis of the time evolution of the individual EPR contributions reveals the disadvantages of quantitative kinetics studies based on the summed EPR intensity of all copper‐based species, as is commonly used in literature for this type of reactions. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1493–1501, 2010
A novel mesogen‐jacketed liquid crystalline electroluminescent polymer with both thiophene and oxadiazole in conjugated side chain
Authors: Yang Qian , Xu Yiding , Jin Hao , Shen Zhihao , Chen Xiaofang , Zou Dechun , Fan Xinghe , Zhou Qifeng 
Published: February 2010

AbstractMesogen‐jacketed liquid crystalline polymers (MJLCPs) with both electron‐transport oxadiazole and hole‐transport thiophene in the side chain were reported for their promising electroluminescent property. Monomers of 2,5‐bis{5‐[(4‐alkoxyphenyl)‐1,3,4‐oxadiazole]thiophen‐2‐yl}styrene (M‐Cm, m is the number of the carbons in the alkoxy groups, m = 8,10) were synthesized and confirmed by 1H‐NMR, mass spectrometry, and elemental analysis. The corresponding polymers were successfully obtained and characterized by thermal analysis, optical spectroscopy, cyclic voltammetry, electroluminescent analysis, polarized light microscopy (PLM), and wide‐angle X‐ray diffraction (WAXD). The polymers exhibited high decomposition temperatures reaching 382 °C and high Tg's reaching 184 °C. The absorption spectra indicated that both the monomers and polymers had little aggregation in film than that in solution, and the absorption spectra of the polymers showed an obvious blue‐shift compared with those of the monomers. Both the monomers and the polymers had blue‐green emission, and the photoluminescence spectra of the polymers in film suggested the formation of excimer or exciplex. The polymers showed lower HOMO energy levels and LUMO energy levels than those of the MJLCPs containing oxadiazole unit reported before. Electroluminescence study with the device configuration of ITO/PEDOT/PVK/polymer/TPBI/Ca/Ag showed maximum brightness and current efficiency of 541 cd/m2 and 0.10 cd/A, which proved that the introduction of directly connected electron‐ and hole‐transport units could greatly improve the EL property of side‐chain conjugated polymers. The phase structures of the polymers were confirmed to be smectic A phase through the results of PLM and WAXD. The annealed samples emitted polarized photoluminescence at room temperature, which indicated potential utility for practical applications in display. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1502–1515, 2010
Polymerized pickering HIPEs: Effects of synthesis parameters on porous structure
Authors: Gurevitch Inna , Silverstein Michael S. 
Published: February 2010

AbstractA polyHIPE is a highly porous polymer synthesized from monomers within the external phase of a high internal phase emulsion (HIPE). The large amount of difficult to remove surfactant needed for HIPE stabilization can affect the properties of the resulting polymer. A Pickering emulsion is a surfactant‐free emulsion stabilized by solid particles that preferentially migrate to the interface. In this article, the synthesis of crosslinked polyacrylate polyHIPEs based on Pickering HIPEs stabilized using silane‐modified silica nanoparticles is described and the effects of the synthesis parameters on the porous structure are discussed. The silane chemistry, silane content, and nanoparticle content had significant effects on the size of the polyhedral, relatively closed‐cell polyHIPE voids that resulted from aqueous‐phase initiation. Increasing the mixing intensity reduced the wall thickness and produced a more open‐cell structure. The locus of initiation had a significant effect on polyHIPE morphology. Organic‐phase initiation yielded larger, more spherical voids from the more extensive coalescence before the structure could be “locked‐in” at the gel point. Most significantly, the nanoparticles were located within the polymer walls rather than at the interface, as might be expected. The void walls were shown to be an assembly of nanoparticle agglomerate shells that become embedded within the polymer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1516–1525, 2010
Tailored composite polymer–metal nanoparticles by miniemulsion polymerization and thiol‐ene functionalization
Authors: van Berkel Kim Y. , Hawker Craig J. 
Published: February 2010

AbstractA simple and modular synthetic approach, based on miniemulsion polymerization, has been developed for the fabrication of composite polymer–metal nanoparticle materials. The procedure produces well‐defined composite structures consisting of gold, silver, or MnFe2O4 nanoparticles (∼10 nm in diameter) encapsulated within larger spherical nanoparticles of poly(divinylbenzene) (∼100 nm in diameter). This methodology readily permits the incorporation of multiple metal domains into a single polymeric particle, while still preserving the useful optical and magnetic properties of the metal nanoparticles. The morphology of the composite particles is retained upon increasing the inorganic content and also upon redispersion in organic solvents. Finally, the ability to tailor the surface chemistry of the composite nanoparticles and incorporate steric stabilizing groups using simple thiol‐ene chemistry is demonstrated. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1594–1606, 2010
Photoresponsive poly(methyl methacrylate)‐b‐azodendron block copolymers prepared by ATRP and click chemistry
Authors: del Barrio Jesús , Oriol Luis , Alcalá Rafael , Sánchez Carlos 
Published: February 2010

AbstractA range of block copolymers (BCs) consisting of a linear poly(methyl methacrylate) (PMMA) block linked to an aliphatic polyester dendron functionalized with azobenzene moieties have been synthesized by sequential atom transfer radical polymerization (ATRP) and Click Chemistry. Two alkyne‐functionalized PMMA homopolymers with different molecular weights were obtained by ATRP and coupled to generations 2 to 4 of azodendrons bearing an azide group at the focal points. In the case of the azodendron with the highest generation number, the length of the flexible spacer attaching the cyanoazobenzene units to the dendron has also been modified. The coupling of both blocks and purity of BCs were checked by gel permeation chromatography, nuclear magnetic resonance, and infrared spectroscopy. The thermal transitions and liquid crystalline behavior of the BCs were investigated by differential scanning calorimetry and polarized‐light optical microscopy. A morphological study was carried out by transmission electron microscopy, using samples annealed at 115 °C. Photo‐induced anisotropy was induced in thin films of these materials after annealed at 115 °C. The highest stable birefringence values were obtained for the BCs bearing 8 and 16 azobenzene units in the dendritic block. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1538–1550, 2010
Colorimetric naked‐eye recognizable anion sensors synthesized via RAFT polymerization
Authors: Jiang Jianbing , Xiao Xiao , Zhao Ping , Tian He 
Published: February 2010

AbstractA polymeric sensor (PTH) containing naphthalimide signal moiety and thiourea recognition moiety for the detection of anions was synthesized by reversible addition‐fragmentation chain transfer (RAFT) polymerization, which can guarantee controllable molecular weight, narrow molecular weight distribution, and precise polymer structure. Both PTH and its corresponding monomer (TH) showed naked‐eye recognizable yellow‐to‐orange changes upon addition of fluoride (F−), acetate (AcO−), and dihydrogen phosphate (H2PO) of low concentration. However, only F− can result in orange‐to‐purple change when the aforementioned anions were added at high concentrations, which was attributed to the deprotonation of the thiourea NH groups and the mechanism was supported by the UV‐Vis absorption spectra and 1H NMR titration. The effect of these anions on thin PTH films was also investigated, and the addition of F− led to obvious spectra change. It was found that other halide anions (Cl−, Br−, and I−) could hardly induce any variation of absorption spectra. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1551–1556, 2010
Nanoparticles consisting of optically active helical polymers: Preparation via aqueous catalytic miniemulsion polymerization and the effects of particles size on their optical activity
Authors: Luo Xiaofeng , Kang Naiwen , Li Lei , Deng Jianping , Yang Wantai 
Published: February 2010

AbstractThis article reports a class of nanoscale materials, that is, optically active nanoparticles consisting of helical‐substituted polyacetylenes. Such nanoparticles were prepared via aqueous catalytic miniemulsion polymerization, by which nanoparticles with a wide range of size (diameter: 60–400 nm) can be easily prepared. The nanoparticles could be obtained in quantitative monomer conversions. Large specific rotations and intense circular dichroism effects demonstrated that the nanoparticles possessed large optical activities; moreover, the optical activities were found to increase with a decrease in particle size. From the obtained polymer nanoparticles and with poly(vinyl alcohol) (PVA) as supporting material, composite films were further prepared and also exhibited considerable optical activities. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1661–1668, 2010
Multiarm star triblock terpolymers via sequential double click reactions
Authors: Durmaz Hakan , Dag Aydan , Gursoy Duygu , Demirel A. Levent , Hizal Gurkan , Tunca Umit 
Published: February 2010

AbstractMultiarm star triblock terpolymers were obtained by using two different click reactions sequentially: Cu(I) catalyzed azide–alkyne and Diels–Alder. The synthetic strategy is described as follows: (poly(methyl methacrylate))n‐(polystyrene)m‐poly(divinyl benzene)) ((PMMA)n‐(PS)m‐polyDVB) multiarm star diblock copolymer was first obtained from an azide–alkyne click reaction of (alkyne‐PS)m‐polyDVB multiarm star polymer with α‐anthracene‐ω‐azide PMMA (anth‐PMMA‐N3), followed by a Diels–Alder click reaction of the anthracene groups at the star periphery with α‐maleimide poly (tert‐butyl acrylate) (PtBA‐MI) or α‐maleimide poly(ethylene glycol) (PEG‐MI) leading to target (PtBA)k‐(PMMA)n‐(PS)m‐polyDVB and (PEG)p‐(PMMA)n‐(PS)m‐polyDVB multiarm star triblock terpolymers. The hydrodynamic diameter of individual multiarm star triblock terpolymers were measured by dynamic light scattering (DLS) to be ∼24–27 nm in consistent with the atomic force microscopy (AFM) images on silicon substrates. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1557–1564, 2010
Synthesis and characterization of a narrow‐bandgap polymer containing alternating cyclopentadithiophene and diketo‐pyrrolo‐pyrrole units for solar cell applications
Authors: Chen Guan‐Yu , Chiang Chien‐Ming , Kekuda Dhananjay , Lan Shang‐Che , Chu Chih‐Wei , Wei Kung‐Hwa 
Published: February 2010

AbstractWe have synthesized a narrow‐bandgap conjugated polymer (PCTDPP) containing alternating cyclopentadithiophene (CT) and diketo‐pyrrolo‐pyrrole (DPP) units by Suzuki coupling. This PCTDPP exhibits a low band gap of 1.31 eV and a broad absorption band from 350 to 1000 nm, which allows it to absorb more available photons from sunlight. A bulk heterojunction polymer solar cell incorporating PCTDPP and C70 at a blend ratio of 1:3 exhibited a high short‐circuit current of 10.87 mA/cm2 and a power conversion efficiency of 2.27%. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1669–1675, 2010
The AFM observation of linear chain and crystalline conformations of ultrahigh molecular weight polyethylene molecules on mica and graphite
Authors: Prokhorov V. V. , Nitta K. 
Published: February 2010

AbstractAtomic force microscopy (AFM) has been applied to visualize expanded linear chain and compact crystalline conformations of ultrahigh molecular weight polyethylene (PE) molecules deposited on mica and graphite from diluted solutions at elevated temperatures. Isolated PE chains are visualized on mica with the apparent negative AFM height and the contour length much shorter than the molecular length. The chain conformations have both the kinked random‐coil sites and the sites of the unexpectedly large two‐dimensional expansion. The crystalline conformations on mica are small single‐molecule rod‐like nanocrystallites and the isolated block‐type “edge‐on” nanolamellae comprising several PE molecules. Noticeable fluctuations of the fold length in the range of approximately 10–20 nm around the averaged value of about 15 nm are observed for nanocrystallites and on tips of some nanolamellae. The explanation of the experimentally observed features of chain surface conformations on mica is proposed. It implies the immobilization of PE molecules in the nm‐thickness salt layer formed on mica surface at ambient conditions after PE deposition and the presence along the chain of multiple expanded chain folds. Only isolated lamellae and lamellar domains of a monolayer height are observed on graphite samples. The substrate/polymer epitaxial incommensurability important for the observation of the PE linear chain surface conformations is discussed from the comparison of the results obtained for mica and graphite, the coil‐to‐crystal intramolecular transformation is assumed to be inhibited on mica surface. The slow disintegration of the original gel structure of PE stock‐solution used for the high‐temperature depositions was found to result in the characteristic large‐scale morphological heterogeneity of the samples. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 766–777, 2010