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Macromolecular Rapid Communications

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https://www.readbyqxmd.com/read/28207179/self-assembled-liquid-crystalline-membranes-form-supramolecular-hydrogels-via-hydrogen-bonding
#1
Youfeng Yue
Developing simple methods to organize nanoscale building blocks into ordered superstructures is a crucial step toward the practical development of nanotechnology. Bottom-up nanotechnology using self-assembly bridges the molecular and macroscopic, and can provide unique material properties, different from the isotropic characteristics of common substances. In this study, a new class of supramolecular hydrogels comprising 40 nm thick linear polymer layers sandwiched between nanolayers of self-assembled amphiphilic molecules are prepared and studied by nuclear magnetic resonance spectroscopy, scanning electronic microscopy, small angle X-ray diffraction, and rheometry...
February 16, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28199759/bioinspired-design-of-a-robust-elastomer-with-adaptive-recovery-via-triazolinedione-click-chemistry
#2
Jing Huang, Lijie Zhang, Zhenghai Tang, Siwu Wu, Nanying Ning, Haibin Sun, Baochun Guo
It is a significant but challenging task to simultaneously reinforce and functionalize diene rubbers. Inspired by "sacrificial bonds", the authors engineer sacrificial hydrogen bonds formed by pendent urazole groups in crosslinked solution-polymerized styrene butadiene rubber (SSBR) via triazolinedione click chemistry. This post-crosslinking modification reveals the effects of the sacrificial bonds based on a consistent covalent network. The "cage effect" of the pre-crosslinked network facilitates the heterogeneous distribution of urazole groups, leading to the formation of hydrogen-bonded multiplets...
February 15, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28198111/synthesis-of-hydroxy-functionalized-cyclic-olefin-copolymer-and-its-block-copolymers-with-semicrystalline-polyolefin-segments
#3
Xiangyang Song, Lijun Yu, Takeshi Shiono, Tariqul Hasan, Zhengguo Cai
Synthesis of hydroxy-functionalized cyclic olefin copolymer (COC) is achieved with remarkably high activity (up to 5.96 × 10(7) g-polymer mol-Ti(-1) h(-1) ) and controlled hydroxy group in a wide range (≈17.1 mol%) by using ansa-dimethylsilylene (fluorenyl)(amido)titanium complex. The catalyst also promotes living/controlled copolymerization to afford novel diblock copolymers consisting of hydroxy-functionalized COC and semicrystalline polyolefin sequence such as polyethylene and syndiotactic polypropylene, where the glass transition temperature of the norbornene/10-undecen-1-ol segment and each block length are controlled by comonomer composition and copolymerization time, respectively...
February 15, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28196300/omnidirectional-shape-memory-effect-via-lyophilization-of-peg-hydrogels
#4
Di Chen, Xuhui Xia, Tuck W Wong, Hao Bai, Marc Behl, Qian Zhao, Andreas Lendlein, Tao Xie
Device applications of shape memory polymers demand diverse shape changing geometries, which are currently limited to non-omnidirectional movement. This restriction originates from traditional thermomechanical programming methods such as uniaxial, biaxial stretching, bending, or compression. A solvent-modulated programming method is reported to achieve an omnidirectional shape memory behavior. The method utilizes freeze drying of hydrogels of polyethylene glycol networks with a melting transition temperature around 50 °C in their dry state...
February 14, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28195679/beyond-donor-acceptor-d-a-approach-structure-optoelectronic-properties-organic-photovoltaic-performance-correlation-in-new-d-a1-d-a2-low-bandgap-conjugated-polymers
#5
Christos L Chochos, Sofia Drakopoulou, Athanasios Katsouras, Benedetta M Squeo, Christian Sprau, Alexander Colsmann, Vasilis G Gregoriou, Alex-Palma Cando, Sybille Allard, Ullrich Scherf, Nicola Gasparini, Negar Kazerouni, Tayebeh Ameri, Christoph J Brabec, Apostolos Avgeropoulos
Low-bandgap near-infrared polymers are usually synthesized using the common donor-acceptor (D-A) approach. However, recently polymer chemists are introducing more complex chemical concepts for better fine tuning of their optoelectronic properties. Usually these studies are limited to one or two polymer examples in each case study so far, though. In this study, the dependence of optoelectronic and macroscopic (device performance) properties in a series of six new D-A1 -D-A2 low bandgap semiconducting polymers is reported for the first time...
February 13, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28195676/investigation-of-tacticity-and-living-characteristics-of-photoredox-mediated-metal-free-ring-opening-metathesis-polymerization
#6
Laura M M Pascual, Adam E Goetz, Adrienne M Roehrich, Andrew J Boydston
This study investigated the microstructures of polymers produced via photoredox-mediated metal-free ring-opening metathesis polymerization. Polynorbornene, poly(exo-dihydrodicyclopentadiene), and poly(endo-dicyclopentadiene) were found to have cis olefin contents of 23%, 24%, and 28%, respectively. Additionally, the cis/trans ratio remained consistent during the course of norbornene polymerization. Polymer tacticity was evaluated by quantitative (13) C NMR spectroscopy, which revealed each polymer to be largely atactic...
February 13, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28195670/a-bunch-like-tertiary-amine-grafted-polysulfone-membrane-for-vrfbs-with-simultaneously-high-proton-conductivity-and-low-vanadium-ion-permeability
#7
Qinglong Tan, Shanfu Lu, Jiangju Si, Haining Wang, Chunxiao Wu, Xianfeng Li, Yan Xiang
Novel polysulfone membranes with bunch-like tertiary amine groups are synthesized with high ion selectivity and outstanding chemical stability for vanadium redox flow batteries (VRFBs). The bunch-like tertiary amine groups simultaneously act as an ionic conductor for proton hopping and vanadium ion transport obstacles. The performance of the membrane is tuned via controlling the grafting degree of the chloromethylated polysulfone. The results show that membranes show increasing proton over vanadium ion (σ/p) selectivity with increasing functional tertiary groups...
February 13, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28195669/responsive-thiolactone-derived-n-substituted-poly-urethane-amide-s
#8
Pieter Espeel, Sensu Celasun, Pinar Sinem Omurtag, Steven Martens, Filip E Du Prez
AB' type monomers containing a thiolactone unit and vinyl ether moiety have been prepared with high yields. Aminolysis of the thiolactone moiety generates the corresponding thiol in situ, and upon UV-irradiation, radical polyaddition occurs in the same medium, yielding linear poly(amide-urethane)s with different side chain residues and (Poly(Ethylene Oxide)) PEO-like backbone. Moreover, these unique polymers feature lower critical solution temperature behavior in water. Systematic modification of the responsive polymers reveals the influence of the variation of the side chains and the backbone structure on the corresponding solubility properties...
February 13, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28169485/borinic-acid-polymer-simplified-synthesis-and-enzymatic-biofuel-cell-application
#9
Xin-Hu Lv, Shun-Shun Li, Cong-Yu Tian, Mao-Mao Yang, Cheng Li, Yan Zhou, Xiao-Li Sun, Jun Zhang, Wen-Ming Wan
A simplified one-pot and less harmful method has been introduced for the synthesis of borinic acid monomer. The corresponding borinic acid polymer (PBA) has been prepared by reversible addition-fragmentation chain transfer polymerization. Property investigations confirm the characteristics of PBA as a new type of "smart material" in the field of thermo-responsive polymer. The potential application of PBA in the field of enzymatic biofuel cell has been illustrated with a wide open circuit potential of 0.92 V...
February 7, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28169482/using-diphenylphosphoryl-azide-dppa-for-the-facile-synthesis-of-biodegradable-antiseptic-random-copolypeptides
#10
Yuji Pu, Yu Du, Mya Mya Khin, Vikashini Ravikumar, Scott A Rice, Hongwei Duan, Mary B Chan-Park
A facile method has been developed for the large-scale synthesis of random copolypeptides composed of multiple (i.e., cationic, hydrophobic, and hydrophilic) amino acids and their relative ratios have been optimized for broad-spectrum antibacterial effect. The copolypeptides obtained have measured compositions close to the design ratios in spite of the differing reactivities of the different amino acids. An optimized random copolypeptide of lysine, leucine, and serine (denoted as KLS-3) mimicking the composition of LL-37 host defense peptide gives broad spectrum antibacterial activity against clinically relevant Gram-negative and Gram-positive bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (PAO1) with minimum inhibitory concentrations (MICs) of 32-64 μg mL(-1) , as well as good MICs against multidrug resistant Gram-negative bacteria of Escherichia coli EC 958 (64 μg mL(-1) ) and Klebseilla pneumoniae PTR3 (128 μg mL(-1) )...
February 7, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28169478/light-switchable-self-healing-hydrogel-based-on-host-guest-macro-crosslinking
#11
Qiaofeng Yang, Ping Wang, Chuanzhuang Zhao, Wenqin Wang, Jingfa Yang, Qiao Liu
A self-healing hydrogel is prepared by crosslinking acrylamide with a host-guest macro-crosslinker assembled from poly(β-cyclodextrin) nanogel and azobenzeneacrylamide. The photoisomerizable azobenzene moiety can change its binding affinity with β-cyclodextrin, therefore the crosslinking density and rheology property of the hydrogel can be tuned with light stimulus. The hydrogel can repair its wound autonomously through the dynamic host-guest interaction. In addition, the wounded hydrogel will lose its ability of self-healing when exposed to ultraviolet light, and the self-healing behavior can be recovered upon the irradiation of visible light...
February 7, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28169476/metallo-polymer-chain-extension-controls-the-morphology-and-release-kinetics-of-microparticles-composed-of-terpyridine-capped-polylactides-and-their-stereocomplexes
#12
Marek Brzeziński, Anna Kacprzak, Marcelo Calderón, Sebastian Seiffert
Control over morphology and porosity of supramolecular complexed polylactide (PLA) microparticles can be achieved by manipulation of the supramolecular interactions between their constituent polymeric building blocks. It is expected that such modular systems are ideal candidates to serve as degradable delivery carriers. In view of this goal, this study reports about a modular fabrication of biodegradable microparticles from terpyridine (TPy) and bisterpyridine (bisTPy) end-functionalized PLAs that can be transiently extended by chain association through differently strong complexation to three metal cations: Ni(2+) , Co(2+) , or Fe(2+) ...
February 7, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28169474/deep-blue-fluorescent-particles-via-microwave-heating-of-polyacrylonitrile-dispersions
#13
Dennis Go, Alena Jurásková, Andreas Hoffmann, Gent Kapiti, Alexander J C Kuehne
This study presents a new method to produce fluorescent particles. Established methods are based on the incorporation of conjugated dye molecules into dielectric polymer matrices or preparation of colloids, which are composed of fluorescent conjugated polymer. By contrast, this study presents a method where dielectric polyacrylonitrile is exposed to microwave radiation leading to an intramolecular cyclization reaction producing π-conjugated segments, which fluoresce blue. During this conversion, the particles shrink in diameter but as an ensemble they retain their monodispersity...
February 7, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28169473/fluorescence-detection-of-microcapsule-type-self-healing-based-on-aggregation-induced-emission
#14
Young Kyu Song, Beomjin Kim, Tae Hee Lee, Jin Chul Kim, Joon Hyun Nam, Seung Man Noh, Young Il Park
An extrinsic self-healing coating system containing tetraphenylethylene (TPE) in microcapsules was monitored by measuring aggregation-induced emission (AIE). The core healing agent comprised of methacryloxypropyl-terminated polydimethylsiloxane, styrene, benzoin isobutyl ether, and TPE was encapsulated in a urea-formaldehyde shell. The photoluminescence of the healing agent in the microcapsules was measured that the blue emission intensity dramatically increased and the storage modulus also increased up to 10(5) Pa after the photocuring...
February 7, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28169470/tandem-ring-opening-metathesis-vinyl-insertion-polymerization-fundamentals-and-application-to-functional-polyolefins
#15
REVIEW
Michael R Buchmeiser
The accomplishments in the copolymerization of ethylene with cyclic olefins such as norborn-2-ene or cis-cyclooctene via tandem ring-opening metathesis polymerization (ROMP) - vinyl insertion polymerization (VIP) are outlined. This approach provides polyolefins with high molecular weight (600,000 < Mn < 4,500,000 g mol(-1) ) and substantial amounts of double bonds along the polymer main chain. Olefinic moieties in ROMP-derived polymers can be converted into hydroxyl, amino, silyl, ester, or carboxylate groups by different means including controlled radical polymerization-based grafting...
February 7, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28166373/aqueous-self-assembly-of-y-shaped-amphiphilic-block-copolymers-into-giant-vesicles
#16
Hanping Li, Yong Jin, Baozhu Fan, Shuangquan Lai, Xiaopeng Sun, Rui Qi
The preparation and aqueous self-assembly of newly Y-shaped amphiphilic block polyurethane (PUG) copolymers are reported here. These amphiphilic copolymers, designed to have two hydrophilic poly(ethylene oxide) (PEO) tails and one hydrophobic alkyl tail via a two-step coupling reaction, can self-assemble into giant unilamellar vesicles (GUVs) (diameter ≥ 1000 nm) with a direct dissolution method in aqueous solution, depending on their Y-shaped structures and initial concentrations. More interesting, the copolymers can self-assemble into various distinct nano-/microstructures, such as spherical micelles, small vesicles, and GUVs, with the increase of their concentrations...
February 6, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28166372/sustained-drug-release-by-thermoresponsive-sol-gel-hybrid-hydrogels-of-poly-n-isopropylacrylamide-co-3-trimethoxysilyl-propyl-methacrylate-copolymers
#17
Zsófia Osváth, Tamás Tóth, Béla Iván
Poly(N-isopropylacrylamide-co-3-(trimethoxysilyl)propyl methacrylate), P(NIPAAm-co-TMSPMA), copolymers with relatively high TMSPMA contents without insoluble fraction are successfully synthesized. Subsequent sol-gel reactions in both the absence and presence of tetraethyl orthosilicate lead to gels with high gel fractions. The resulting gels undergo gel collapse at 28.6-28.7 °C, i.e., below that of poly(N-isopropylacrylamide) homopolymer of 34.3 °C. Unexpectedly, the theophylline-loaded hybrid gels release the drug not only below but also above the gel collapse temperature (GCT) with considerable rates and released amounts of drug...
February 6, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28160361/nonmigrating-equivalent-substitutes-for-pvc-dop-formulations-as-shown-by-a-tg-study-of-pvc-with-covalently-bound-peo-ppo-oligomers
#18
Rodrigo Navarro, Tülin Gacal, Melike Ocakoglu, Carolina García, Carlos Elvira, Alberto Gallardo, Helmut Reinecke
Monoamino functionalized ethylenoxide (EO)/propylenoxide oligomers (Jeffamine) are linked chemically to poly(vinyl chloride) (PVC) using trichlorotriazine chemistry in order to prepare nonmigrating internally plasticized materials. The dependence of the plasticizer efficiency on both the number of anchoring points to the chains and the PVC/plasticizer compatibility is investigated using oligomers of different molecular weight and hydrophilic-hydrophobic balance. Hydrophilic oligomers (containing predominantly EO) of molecular weights between 2000 and 5000 g mol(-1) exhibit excellent plasticizer efficiency, nearly identical to di-2-ethylhexylphthalate (DOP) in conventional PVC/DOP mixtures and may therefore be used as nonmigrating equivalents for DOP...
February 3, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28160349/integration-of-cuaac-polymerization-and-controlled-radical-polymerization-into-electron-transfer-mediated-click-radical-concurrent-polymerization
#19
Wentao Xue, Jie Wang, Ming Wen, Gaojian Chen, Weidong Zhang
The successful chain-growth copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) polymerization employing Cu(0)/pentamethyldiethylenetriamine (PMDETA) and alkyl halide as catalyst is first investigated by a combination of nuclear magnetic resonance, gel-permeation chromatography, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. In addition, the electron transfer mediated "click-radical" concurrent polymerization utilizing Cu(0)/PMDETA as catalyst is successfully employed to generate well-defined copolymers, where controlled CuAAC polymerization of clickable ester monomer is progressed in the main chain acting as the polymer backbone, the controlled radical polymerization (CRP) of acrylic monomer is carried out in the side chain...
February 3, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28117523/helical-microfilaments-with-alternating-imprinted-intrinsic-curvatures
#20
Pedro Emanuel Santos Silva, Maria Helena Godinho
There has been an intense research for developing techniques that can produce filaments with helical shapes, given the widespread of potential applications. In this work, how helices with different curvatures can be precisely imprinted in microfilaments is shown. It is also shown that using this technique, it is possible to produce, in a single fiber, helices with different curvatures. This striking and innovative behavior is observed when one side of the stretched filaments is irradiated with UV light, modifying the mechanical properties at surface...
January 24, 2017: Macromolecular Rapid Communications
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