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1.
Yuanjing Cui Guodong Qian Lujian Chen Zhiyu Wang Minquan Wang 《Macromolecular rapid communications》2007,28(20):2019-2023
A new sol‐gel hybrid film based on heterocyclic chromophore, namely 2‐[4′‐(N‐ethyl‐N‐hydroxyethyl)amino phenyl azo]‐4,5‐dicyanoimidazole (IZ), has been synthesized and characterized. The hybrid system possesses a high chromophore loading density up to 65 wt.‐% without observing a phase separation. The initial decomposition temperatures of the chromophore and hybrid material were determined to be 260 and 272 °C, respectively. Poled films show a fairly high and stable nonlinear optical (NLO) response, even at an elevated temperature.
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Combinatorial libraries of segmented polyurethaneurea with gradients in curing temperature were prepared and characterized using a novel high‐throughput mechanical instrument. Stress/strain profiles were taken at different temperature positions on the libraries, and a structure/property relationship between microstructure and mechanical properties was established by correlating the measured strength and strain at break to high‐throughput AFM and FT‐IR measurements on the same library. These results demonstrate the feasibility of rapid and accurate screening of mechanical properties, and their correlation to structure, by using gradient combinatorial polymer libraries.
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Ping Xu Xijiang Han Chao Wang Bin Zhang Xiaohong Wang Hsing‐Lin Wang 《Macromolecular rapid communications》2008,29(16):1392-1397
Polyaniline‐polypyrrole (PANI‐PPy) nanofibers with high aspect ratios have been synthesized by a one‐step, surfactant‐assisted chemical oxidative polymerization from mixtures of aniline (An) and pyrrole (Py) monomers. PANI‐PPy nanofibers synthesized with an excess of either PANI or PPy show similar spectral (UV‐vis and FT‐IR) characteristics as the individual homopolymers, whereas nanofibers from an equimolar mixture of An and Py display unique spectral characteristics. PANI‐PPy nanofibers undergo a spontaneous redox reaction with metal ions to produce metal nanoparticles with various morphologies and/or sizes. These findings may open new opportunities for synthesizing functional polymer nanofibers and metal nanoparticles with controllable sizes and/or morphologies.
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Summary: Tetraaniline‐block‐poly(L ‐lactide) diblock oligomers are synthesized via ring‐opening polymerization. The diblock oligomers cast from an L ‐lactide selective solvent (chloroform) show spherical aggregates for the leucoemeraldine state, and ring‐like structures that are composed of much smaller spherical aggregates for the emeraldine state. The formation mechanisms of the two different surface morphologies are discussed in detail.
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A single cylindrical polyelectrolyte brush is studied by self‐consistent field (SCF) theory and the results compared with predictions from scaling theory. It is shown that the SCF theory results give the general trends as well as insight into the crossover regions between different regimes. The density profiles of the polyions and small ions indicate that the systems are locally electroneutral. The salted brush bears characteristics similar to those of a neutral brush. Counter‐intuitively, the chains are not uniformly stretched in the osmotic regime. The free‐end monomers shift to the outer region and an exclusion zone appears and grows with decreasing of salt concentration.
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Spherical single‐chain‐particles of poly(N‐isopropylacrylamide) were prepared in aqueous solution above the lower critical solution temperature upon the addition of sodium dodecyl sulfate. The size of the single‐chain‐particles was investigated by means of transmission electron microscopy and viscosity measurements of the corresponding solutions, indicating the absence of inter‐chain entanglements among the single‐chain‐particles.
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Itsuro Tomatsu Akihito Hashidzume Akira Harada 《Macromolecular rapid communications》2006,27(4):238-241
Summary: We have successfully constructed a redox‐responsible hydrogel system by combination of β‐cyclodextrin (β‐CD), dodecyl‐modified poly(acrylic acid) [p(AA/C12)], and a redox‐responsive guest, ferrocenecarboxylic acid (FCA). In the reduced state of FCA, the ternary mixture exhibited a gel‐like behavior, whereas, in its oxidized state, the mixture exhibited a sol behavior.
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Adele Mucci Francesca Parenti Luisa Schenetti 《Macromolecular rapid communications》2003,24(9):547-550
A new copolymer bearing a cysteine moiety, designed for molecular interaction, metal‐ion detection, and chiral recognition, was synthesised starting from the dibromo derivative of methyl N‐(tert‐butoxycarbonyl)‐S‐thien‐3‐ylcysteinate and distannylthiophene through a Stille coupling reaction. UV‐vis spectroscopy, circular dichroism, NMR spectroscopy, and gel permeation chromatography analyses evidenced that this polymer is able to form self‐assembling structures, through the formation of a hydrogen‐bond network, not only in the solid state but also in solution.
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Based on the Hammett equation, a general method is established to relate the polycondensation monomer reactivity with both the monomer structural parameters and the properties of the solvent used for the non‐equilibrium ternary copolycondensation to give copolyamides. Linear plots of the logarithm of the monomer reactivity ratio, log r, versus structure parameter ΔpK could be represented by the equation log r = ρΔpK.
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Antje Britze Katrin Moosmann Evelin Jhne Hans‐Jürgen Adler Dirk Kuckling 《Macromolecular rapid communications》2006,27(22):1906-1912
Summary: Phosphonate groups were introduced into block copolymers of styrene derivatives either as single end‐groups or as small blocks using nitroxide‐mediated radical polymerization. In order to combine the hydrophobic and hydrophilic segments, block copolymers with N,N‐dimethyl acrylamide were synthesized. After hydrolysis to phosphonic acid groups, adsorption of the polymer onto metal oxides was possible.
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Zhiyong Zhang Quli Fan Pengfei Sun Lulin Liu Xiaomei Lu Bo Li Yiwu Quan Wei Huang 《Macromolecular rapid communications》2010,31(24):2160-2165
Grafted conjugated polyelectrolytes were synthesized for the first time and characterized. The polymers demonstrated properties of a convenient and efficient protocol for creating Hg2+ sensors. The unique character of the new material comes from an anionic counterion nature with no external cofactors, and imparts high selectivity and fast detection for mercury ion in a fluorescence probe. The concept may be potentially applied to create new sensors for monitoring other ions.
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Jun Xu Yujie Fang Peihua Ren Haichang Zhang Erqian Guo Wenjun Yang 《Macromolecular rapid communications》2008,29(16):1415-1420
High molecular weight poly(9,10‐bis(p‐(2‐ethylhexyloxy)phenyl)‐2,6‐anthracenevinylene) (2,6‐PAV) was synthesized with 2,6‐dimethylanthraquinone as a key intermediate. The as‐synthesized polymer is readily soluble in common organic solvents and can be used for spin‐coating. The as‐synthesized polymer exhibits a broad absorption band ranging from 280 to 520 nm and a bluish green emission band with a peak at 500 nm. The polymer shows good thermal stability, and no distinct glass transition is observed. A simple device with the configuration ITO/PEDOT:PSS/2,6‐PAV/Ba/Al showed a turn‐on voltage of 4.8 V and a maximal brightness of 340 cd · m−2.
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Leendert W. Schwab Renee Kroon Arend Jan Schouten Katja Loos 《Macromolecular rapid communications》2008,29(10):794-797
The synthesis of poly(β‐alanine) by Candida antarctica lipase B immobilized as novozyme 435 catalyzed ring‐opening of 2‐azetidinone is reported. After removal of cyclic side products and low molecular weight species pure linear poly(β‐alanine) is obtained. The formation of the polymer is confirmed with 1H NMR spectroscopy and MALDI‐TOF mass spectrometry. The average degree of polymerization of the obtained polymer is limited to = 8 by its solubility in the reaction medium. Control experiments with β‐alanine as a substrate confirmed that the ring structure of the 2‐azetidinone is necessary to obtain the polymer.
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Investigations on the self‐assembly of block copolymers in solution have in some way a less well‐studied history than the study of their phase separation in the solid state, and many aspects are yet not completely understood. Here we focus on the behavior of a specific class of copolymers, namely semicrystalline block copolymers, capable of forming cylindrical aggregates in a solvent selective for the non‐crystalline, complementary block. A common model of micellization is proposed, in principle applicable to most of these copolymeric systems.
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Adhesion of immiscible polymers during two‐component injection moulding may be improved by transreactions of properly functionalised components. We performed MC simulations based on the three‐dimensional coarse‐grained bond fluctuation model (BFM) including a thermal interaction potential in with energy to characterise the behaviour of several selected types of chemical reactions, which are governed by activation energies of EA = 0, 1, 3 and 5 kBT. The consumption of reactive monomers for all the reactions in the time interval below the Rouse time τR exhibits a typical crossover from a kinetic‐controlled to a diffusion‐controlled behaviour and can be described by a bimolecular kinetic ansatz.
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Summary: A novel non‐aqueous emulsion system, consisting of cyclohexane as the continuous and acetonitrile as the dispersed phase, is described. Stabilization of the system can be achieved by using polyisoprene‐block‐poly(methyl methacrylate) copolymers as emulsifiers. The suitability of this system for performing water‐sensitive, catalytic, and oxidative polymerizations and polycondensations is demonstrated by the synthesis of poly(3,4‐ethylenedioxythiophene), poly(thiophene‐3‐yl‐acetic acid), and polyacetylene. In all cases spherical nanoparticles with diameters as small as 23 nm can be obtained.
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Anja S. Goldmann Christine Schdel Andreas Walther Jiayin Yuan Katja Loos Axel H. E. Müller 《Macromolecular rapid communications》2010,31(18):1608-1615
The functionalization of magnetite (Fe3O4) nanoparticles with dopamine‐derived clickable biomimetic anchors is reported. Herein, an alkyne‐modified catechol‐derivative is employed as the anchor, as i) the catechol‐functional anchor groups possess irreversible covalent binding affinity to Fe3O4 nanoparticles, and ii) the alkyne terminus enables further functionalization of the nanoparticles by the grafting‐onto approach with various possibilities offered by ‘click’ chemistry. In the present work, azido‐end group functionalized Rhodamine and poly(ethylene glycol) (PEG) are utilized to coat the iron oxide nanoparticles to make them fluorescent and water soluble.
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A facile microwave method (MW) is described that accomplishes alignment and decoration of noble metals on carbon nanotubes (CNT) wrapped with carboxymethyl cellulose (CMC). Carbon nanotubes such as single‐ and multi‐walled, and Buckminsterfullerene (C‐60) are well dispersed using the sodium salt of CMC under sonication. Addition of respective noble metal salts then generates noble metal‐decorated CNT composites at room temperature. However, aligned nanocomposites of CNTs could only be generated by exposing the above nanocomposites to MW irradiation. The CNT composites are characterized using scanning electron microscopy, energy dispersive X‐ray analysis, X‐ray mapping, transmission electron microscopy, and UV‐visible spectroscopy. The general preparative procedure is versatile and provides a simple route to manufacturing useful metal‐coated CNT nanocomposites.