keyword
MENU ▼
Read by QxMD icon Read
search

Ladder polymer

keyword
https://www.readbyqxmd.com/read/30282946/fatigue-performance-of-rc-beams-strengthened-with-cfrp-under-overloads-with-a-ladder-spectrum
#1
Zhan-Biao Chen, Pei-Yan Huang, Zheng-Wei Li, Xin-Yan Guo, Chen Zhao, Xiao-Hong Zheng, Yi Yang
Vehicle overload is detrimental to bridges and traffic safety. This paper presents a study on the fatigue performance of typical reinforced concrete (RC) beams of highway bridges under vehicle overload. A definition method of vehicle overload and a construction method of overload ladder spectrum were first proposed based on traffic data acquisition, statistical analysis and structural calculation of the highway bridges in Guangzhou. A fatigue experimental method was also proposed with the three-ladder vehicle overload spectrum, and the fatigue tests of 15 RC beams strengthened with carbon fiber reinforced polymer (CFRP) under three loading levels were then carried out...
October 3, 2018: Sensors
https://www.readbyqxmd.com/read/30247790/scope-and-limitations-of-the-dehydrogenative-generation-of-graphenic-nanoribbons-from-methylene-bridged-aromatic-ladder-polymers
#2
Marie-Claire Ockfen, Michael Forster, Ullrich Scherf
A synthetic route to solubilized graphenic nanoribbons (GNRs) by oxidation of methylene-bridged, aromatic ladder polymers is presented. Hereby, the ladder polymer precursors are finally 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (or DDQ) oxidized into the desired GNRs. However, a detailed UV-vis analysis shows already partial oxidation/dehydrogenation during aqueous work-up under loss of ≈50% of the bridgehead hydrogens as well as some indications for overoxidation with DDQ under formation of quinoid carbonyl defects, additionally driven by a reduction of the number of quinoid (quinodimethane) structural units...
September 24, 2018: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/30177780/dynamic-self-correcting-nucleophilic-aromatic-substitution
#3
Wen Jie Ong, Timothy M Swager
Dynamic covalent chemistry, with its ability to correct synthetic dead-ends, allows for the synthesis of elaborate extended network materials in high yields. However, the limited number of reactions amenable to dynamic covalent chemistry necessarily confines the scope and functionality of materials synthesized. Here, we explore the dynamic and self-correcting nature of nucleophilic aromatic substitution (SN Ar), using ortho-aryldithiols and ortho-aryldifluorides that condense to produce redox-active thianthrene units...
October 2018: Nature Chemistry
https://www.readbyqxmd.com/read/30073729/highly-luminescent-ladderized-fluorene-copolymers-based-on-b-n-lewis-pair-functionalization
#4
Abdullah F Alahmadi, Roger A Lalancette, Frieder Jäkle
A new B-N functionalized polyaromatic building block for conjugated hybrid polymers is developed. Bromine-functionalized dipyridylfluorene is first subjected to Lewis-base-directed electrophilic borylation and subsequently incorporated into conjugated polymers via transition-metal-catalyzed cross-coupling reactions. The borane monomer exhibits bright blue luminescence in solution, as a result of the rigid ladder-type structure generated upon electrophilic borylation. Yamamoto coupling gives rise to a homopolymer and Stille coupling to a vinylene-bridged copolymer...
August 3, 2018: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/30009536/dna-ladders-can-be-used-to-size-polyphosphate-resolved-by-polyacrylamide-gel-electrophoresis
#5
Stephanie A Smith, Yan Wang, James H Morrissey
PAGE is often used to resolve inorganic polyphosphates (polyP), but unfortunately polyP size ladders are not commercially available. Since several dyes that are commonly used to detect nucleic acids in gels also stain polyP, we examined the utility of commercially available DNA size ladders for estimating polyP polymer lengths by gel electrophoresis. Narrow size fractions of polyP were prepared and their polymer lengths were quantified using NMR. Commercially available DNA ladders and these polyP fractions were then subjected to PAGE to determine the relationship between migration of DNA vs polyP, which was found to be: log10 (dsDNA length in bp) = 1...
October 2018: Electrophoresis
https://www.readbyqxmd.com/read/29984526/single-crystal-to-single-crystal-scsc-linear-polymerization-of-a-desymmetrized-anthraphane
#6
Marco Servalli, Nils Trapp, A Dieter Schlüter
In this work we present one of the rare cases of single-crystal-to-single-crystal (SCSC) linear polymerizations, resulting in a novel ladder-type polymer. The polymerization is based on the photoinduced [4+4]-cycloaddition reactions between trifunctional anthracene-based monomers. The careful design of the monomer anthraphane-tri(OMe), results in perfectly stacked anthracene pairs in the crystal structure, with Schmidt's distances d=3.505-3.666 Å and shift s=1.109 Å, allowing a selective linear polymerization in quantitative yields and in a matter of minutes, without compromising the integrity of the single crystals...
October 9, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29952564/photochemical-structural-transformation-of-a-linear-1d-coordination-polymer-impacts-the-electrical-conductivity
#7
Basudeb Dutta, Arka Dey, Chittaranjan Sinha, Partha Pratim Ray, Mohammad Hedayetullah Mir
A pair of 4-(1-naphthylvinyl)pyridine (4-nvp) ligands has been successfully aligned in head-to-tail fashion in a one-dimensional (1D) double chain ladder polymer [Cd(adc)(4-nvp)2 (H2 O)] n (1; H2 adc = acetylenedicarboxylic acid) that undergoes a photochemical [2 + 2] cycloaddition reaction accompanied by single-crystal to single-crystal (SCSC) structural transformation from a 1D chain to a 2D layer structure. These structural changes have a significant impact on the conductivity and Schottky nature of the compound...
July 16, 2018: Inorganic Chemistry
https://www.readbyqxmd.com/read/29911315/ladder-type-heteroarene-based-organic-semiconductors
#8
REVIEW
Jianhua Chen, Kun Yang, Xin Zhou, Xugang Guo
The fusion of heteroaromatic rings into ladder-type heteroarenes can stabilize frontier molecular orbitals and lead to improved physicochemical properties that are beneficial for applications in various optoelectronic devices. Thus, ladder-type heteroarenes, which feature highly planar backbones and well-delocalized π conjugation, have recently emerged as a promising type of organic semiconductor with excellent device performance in organic photovoltaics (OPVs) and organic field-effect transistors (OFETs)...
September 17, 2018: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29845148/syntheses-crystal-structures-adsorption-properties-and-visible-photocatalytic-activities-of-highly-stable-pb-based-coordination-polymers-constructed-by-2-2-carboxyphenyl-imidazo-4-5-f-1-10-phenanthroline-and-bridging-linkers
#9
Zhi-Min Li, Yu Qiao, Chun-Bo Liu, Yan-Feng Zhou, Xiu-Yan Wang, Paul A Charpentier, Guang-Bo Che, William Z Xu, Li-Hui Liu, En-Wei Zhu
Five highly stable coordination polymers assembled by 2-(2-carboxyphenyl)imidazo(4,5-f)-(1,10)phenanthroline (2-HNCP) and different aromatic carboxylic acid ligands, namely, [Pb(2-NCP)(L1)]n (1), [Pb2(2-NCP)2(L2)]n·2nH2O (2), [Pb2(2-NCP)2(L2)]n (3), [Pb(2-NCP)(L3)0.5]n (4) and [Pb2(2-NCP)2(L4)]n (5), where HL1 = pyridine-4-carboxylic acid, H2L2 = 2-amino-1,4-benzenedicarboxylic acid, H2L3 = 1,4-benzenedicarboxylic acid and H2L4 = 2-hydroxy-1,4-benzenedicarboxylic acid, have been synthesized under hydrothermal conditions...
June 12, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29843471/the-selectivity-of-polymers-imprinted-with-amines
#10
Zsanett Dorkó, Anett Nagy-Szakolczai, Blanka Tóth, George Horvai
One of the main reasons for making molecularly imprinted polymers (MIPs) has been that MIPs interact selectively with a specific target compound. This claim is investigated here with the example of a widely used type of noncovalent MIP, the MIP for the beta blocker propranolol. Adsorption isotherms of this MIP and of a nonimprinted control polymer (NIP), respectively, have been measured with a series of compounds in the porogen solvent acetonitrile. The results, visualized as "selectivity ladders", show that the MIP binds propranolol and many other amines better than the NIP does, but the selectivity of the MIP is actually inferior to that of the NIP...
May 29, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29766573/asymmetrical-ladder-type-donor-induced-polar-small-molecule-acceptor-to-promote-fill-factors-approaching-77-for-high-performance-nonfullerene-polymer-solar-cells
#11
Wei Gao, Miao Zhang, Tao Liu, Ruijie Ming, Qiaoshi An, Kailong Wu, Dongjun Xie, Zhenghui Luo, Cheng Zhong, Feng Liu, Fujun Zhang, He Yan, Chuluo Yang
In this work, an effectual strategy of constructing polar small molecule acceptors (SMAs) to promote fill factor (FF) of nonfullerene polymer solar cells (PSCs) is first reported. Three asymmetrical SMAs of IDT6CN, IDT6CN-Th, and IDT6CN-M, which own large dipole moments, are designed and synthesized. The PSCs based on three polar SMAs exhibit apparently higher FFs compared with their symmetrical analogues. The asymmetrical design strategy accompanied with side chain and end group engineering makes IDT6CN-Th- and IDT6CN-M-based nonfullerene PSCs achieve high power conversion efficiency with FFs approaching 77%...
June 2018: Advanced Materials
https://www.readbyqxmd.com/read/29656642/-semi-ladder-type-bithiophene-imide-based-all-acceptor-semiconductors-synthesis-structure-property-correlations-and-unipolar-n-type-transistor-performance
#12
Yingfeng Wang, Han Guo, Alexandra Harbuzaru, Mohammad Afsar Uddin, Iratxe Arrechea-Marcos, Shaohua Ling, Jianwei Yu, Yumin Tang, Huiliang Sun, Juan Teodomiro López Navarrete, Rocio Ponce Ortiz, Han Young Woo, Xugang Guo
Development of high-performance unipolar n-type organic semiconductors still remains as a great challenge. In this work, all-acceptor bithiophene imide-based ladder-type small molecules BTI n and semiladder-type homopolymers PBTI n ( n = 1-5) were synthesized, and their structure-property correlations were studied in depth. It was found that Pd-catalyzed Stille coupling is superior to Ni-mediated Yamamoto coupling to produce polymers with higher molecular weight and improved polymer quality, thus leading to greatly increased electron mobility (μe )...
May 16, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29617315/facile-synthesis-of-nitrogen-and-oxygen-co-doped-clews-of-carbon-nanobelts-for-supercapacitors-with-excellent-rate-performance
#13
Liang Yu, Shaozhong Zeng, Xierong Zeng, Xiaohua Li, Hongliang Wu, Yuechao Yao, Wenxuan Tu, Jizhao Zou
Facile synthesis of carbon materials with high heteroatom content, large specific surface area (SSA) and hierarchical porous structure is critical for energy storage applications. In this study, nitrogen and oxygen co-doped clews of carbon nanobelts (NCNBs) with hierarchical porous structures are successfully prepared by a carbonization and subsequent activation by using ladder polymer of hydroquinone and formaldehyde (LPHF) as the precursor and ammonia as the activating agent. The hierarchical porous structures and ultra-high SSA (up to 2994 m² g−1 ) can effectively facilitate the exchange and transportation of electrons and ions...
April 4, 2018: Materials
https://www.readbyqxmd.com/read/29565593/structural-information-for-conjugated-polymers-from-optical-modeling
#14
Max Marcus, Jonathan D Milward, Anna Köhler, William Barford
We use a Frenkel-Holstein model of uncoupled chains in the adiabatic limit to simulate the optical spectra of the conjugated polymer ladder-type poly( p-phenylene) derivative (MeLPPP), which is a planar conjugated polymer with especially low interchain interactions. The theoretical calculations correctly reproduce the vibronic spectra and yield reasonable torsion angles between adjacent phenyl rings. The success of this approach indicates that, in contrast to interchain coupling, the strong electronic coupling along a polymer chain is more appropriately described in the adiabatic limit...
April 12, 2018: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/29505252/structures-thermodynamic-relations-and-magnetism-of-stable-and-metastable-ni-ncs-2-coordination-polymers
#15
Tristan Neumann, Magdalena Ceglarska, Luzia S Germann, Michał Rams, Robert E Dinnebier, Stefan Suckert, Inke Jess, Christian Näther
Reaction of Ni(NCS)2 with 4-aminopyridine in different solvents leads to the formation of compounds with the compositions Ni(NCS)2 (4-aminopyridine)4 (1), Ni(NCS)2 (4-aminopyridine)2 (H2 O)2 (2), [Ni(NCS)2 (4-aminopyridine)3 (MeCN)]·MeCN (3), and [Ni(NCS)2 (4-aminopyridine)2 ] n (5-LT). Compounds 1, 2, and 3 form discrete complexes, with octahedral metal coordination. In 5-LT the Ni cations are linked by single thiocyanate anions into chains, which are further connected into layers by half of the 4-aminopyridine coligands...
March 19, 2018: Inorganic Chemistry
https://www.readbyqxmd.com/read/29377665/s-n-heteroacene-based-copolymers-for-highly-efficient-organic-field-effect-transistors-and-organic-solar-cells-critical-impact-of-aromatic-subunits-in-the-ladder-%C3%AF-system
#16
Chin-Lung Chung, Hsieh-Chih Chen, Yun-Siou Yang, Wei-Yao Tung, Jian-Wei Chen, Wen-Chang Chen, Chun-Guey Wu, Ken-Tsung Wong
Three novel donor-acceptor alternating polymers containing ladder-type pentacyclic heteroacenes (PBo, PBi, and PT) are synthesized, characterized, and further applied to organic field effect transistors (OFETs) and polymer solar cells. Significant aspects of quinoidal characters, electrochemical properties, optical absorption, frontier orbitals, backbone coplanarity, molecular orientation, charge carrier mobilities, morphology discrepancies, and the corresponding device performances are notably different with various heteroarenes...
February 21, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29318706/complementary-logic-circuits-based-on-high-performance-n-type-organic-electrochemical-transistors
#17
Hengda Sun, Mikhail Vagin, Suhao Wang, Xavier Crispin, Robert Forchheimer, Magnus Berggren, Simone Fabiano
Organic electrochemical transistors (OECTs) have been the subject of intense research in recent years. To date, however, most of the reported OECTs rely entirely on p-type (hole transport) operation, while electron transporting (n-type) OECTs are rare. The combination of efficient and stable p-type and n-type OECTs would allow for the development of complementary circuits, dramatically advancing the sophistication of OECT-based technologies. Poor stability in air and aqueous electrolyte media, low electron mobility, and/or a lack of electrochemical reversibility, of available high-electron affinity conjugated polymers, has made the development of n-type OECTs troublesome...
March 2018: Advanced Materials
https://www.readbyqxmd.com/read/29265501/designed-cluster-assembly-of-multidimensional-titanium-coordination-polymers-syntheses-crystal-structure-and-properties
#18
Chao Wang, Chao Liu, Hong-Rui Tian, Lei-Jiao Li, Zhong-Ming Sun
The exploitation of new titanium-based coordination polymers (Ti CPs) with high crystallinity is difficult but highly desirable for their potential applications in photocatalysis. Herein, a cluster-cooperative assemble strategy is developed to synthesize Ti CPs. By utilizing various bifunctional ligands containing carboxylate acids and N-donor groups, we successfully assembled the zero-dimensional (0D) [(Ti3 O)(iPrO)8 ]2+ or [(Ti4 O2 )(iPrO)6 ]6+ clusters into one-dimensional (1D) tube-, ribbon-, or helical chain-shape architectures, two-dimensional (2D) layered structures, and a rare parallel 2D→three-dimensional (3D) polycatenation framework with various copper iodide dopants, including rhombus- or wing-shaped Cu2 I2 and tetrahedron- or ladder-shaped Cu4 I4 ...
February 26, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29215760/synergistic-effects-of-selenophene-and-extended-ladder-type-donor-units-for-efficient-polymer-solar-cells
#19
Hua-Chun Wang, Qing-Ya Li, Hong-Bo Yin, Xiancheng Ren, Kai Yao, Yonghao Zheng, Yun-Xiang Xu
Two pairs of polymer donor materials based on indacenodithiophene (IDT) and indacenodithieno[3,2-b]thiophene (IDTT) as the donor units are synthesized. Thiophene or selenophene is introduced as the π-bridge units and electron-deficient fluorine-substituted quinoxaline is used as acceptor unit. Selenophene-containing polymers PIDT-DFQ-Se and PIDTT-DFQ-Se show redshifted absorption and narrower bandgaps. Combined with IDTT donor unit, PIDTT-DFQ-Se shows the highest absorption coefficient. Both the IDTT unit and selenophene unit have positive effects on the hole mobilities, making PIDTT-DFQ-Se the highest one...
January 2018: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/29178626/supramolecular-chirality-issues-in-unorthodox-naphthalene-diimide-gelators
#20
Goutam Ghosh, Mithun Paul, Tsuneaki Sakurai, Wakana Matsuda, Shu Seki, Suhrit Ghosh
Herein, the self-assembly of a few 1,3-dihydroxyl functionalized naphthalene diimide (NDI) derivatives has been reported with particular emphasis on the impact of chirality on gelation and the effect of self-assembly on charge-carrier mobility. A nonconventional gelator (R)-NDI, devoid of any long alkyl chains, exhibited spontaneous gelation in tetra-chloroethylene (TCE). Based on X-ray crystallography and powder X-ray diffraction studies, it was established that a ladder-like hydrogen-bonded chain formation between the 1,3-dihydroxyl group leads to the fibrillar structures with preferential helicity...
February 6, 2018: Chemistry: a European Journal
keyword
keyword
171617
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"