LIQUID CRYSTALS
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2012
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IF 1.858
Fafu Yang,Jianwei Xie,Hongyu Guo,Bingting Xu,Congcong Li
Series of novel 1,3,5-triazine-based triphenylene oligomers 7, 10 and 12 with large bridging polyaromatic core were designed and synthesised by simple procedures in high yields. Their structures were confirmed by FTIR, 1H NMR, ESI-MS and elemental analyses. Their mesomorphic behaviours were studied by differential scanning calorimetry, polarising optical microscopy and X-ray diffraction. 1,3,5-triazine-based triphenylene monomer 7 has no mesomorphic property, but 1,3,5-triazine-based triphenylene dimer 10 and 1,3,5-triazine-based triphenylene trimer 12 possess excellent mesomorphic properties. The mesomorphic temperature range of compound 12 was as wide as 180°C. These studies indicated that the mesomorphic properties were determined by the numbers of triphenylene units. More units of triphenylene in the oligomers resulted in better mesomorphic properties.
研究领域:
材料科学
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化学
✓ 已验证
产品关联
DOI
高影响因子
SOFT MATERIALS
·
2013
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IF 1.429
Fafu Yang,Lihong Zhang,Bingting Xu,Xiaoyuan Su,Hongyu Guo
The syntheses of novel triphenylene-ferrocene dyads linked by long or short chain containing conjugated structures were reported in good yields. Their electrochemical properties and mesophase behaviors were investigated by cyclic voltammetry, differential scanning calorimetry, polarizing optical microscopy, and X-ray diffraction, respectively. Triphenylene-ferrocene dyad with long chain containing conjugated structure 5 possessed redox property but no mesomorphic property. Triphenylene-ferrocene dyad with short chain containing conjugated structure 7 exhibited not only reversible electrochemical response property but also ordered hexagonal columnar mesophase for the first time.
[Supplementary materials are available for this article. Go to the publisher's online edition of Soft Materials for the following free supplemental resource(s): First Triphenylene-Ferrocene Dyad with Redox Behavior and Mesomorphic Property]
研究领域:
材料科学
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电化学
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分子设计与合成
✓ 已验证
DOI
高影响因子
ACS Applied Nano Materials
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2021
·
IF 5.097
Linfeng Liang,Ke-Yu Niu,Linjie Zhang,Jiayue Tian,Kang Zhou,Xiao-Lu Wang,Xian-Ming Zhang,Maochun Hong
Tailoring relatively inert Cu oxides for high-performance oxygen evolution reaction (OER) electrocatalysts is of great practical significance but extremely challenging. Herein, CuO MCSs enriched with O vacancies have been fabricated via an appealing metal–organic framework (MOF)-based topotactic alkalization route for the first time. Mechanism analysis indicates that the formation of the CuO mesocrystal superstructure undergoes a gradual structural evolution from nanocrystal to nanobelt and then to nanosheet with escalating order. The porous two-dimensional nanosheet coupled with mesocrystal characteristic endows CuO MCSs with rich surface active sites and significantly improved electric conductivity. When served as an OER electrocatalyst in the alkaline media, the CuO MCS exhibits an overpotential of 304 mV at 10 mA cm–2 and a stable delivery of the OER current for more than 15 h, which surpasses most of the Cu oxide OER electrocatalysts ever reported. Theoretical calculations indicate that high OER activity of CuO MCSs can be traced to the modified electronic structure caused by the O vacancies, resulting in much enhanced Cu 3d–O 2p covalency as well as lifted d-band center, which alters CuO MCSs into a half-metallic nature with optimized binding strength toward O-containing intermediates for OER. This work could provide valuable insights into the design of other MOF-derived advanced catalysts for OER and beyond.
研究领域:
材料科学
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电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF PORPHYRINS AND PHTHALOCYANINES
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2018
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IF 1.217
Xiangfei Kong,Hongkang Gong,Shengping Dai,Wei Yao,Linping Mu,Shufen Zhang,Guixia Wang
Five novel dyads, consisting of a tetraphenylporphyrine unit connected to a perylene monoimide diester unit via a flexible bridge -CONH-(CH 2 ) n - (n = 4, 6, 8, 10 and 12), have been synthesized. Their structures were characterized by 13 C and 1 H nuclear magnetic resonance spectroscopy, infrared spectroscopy, mass spectrometry and elemental analysis. The UV-vis absorption spectra revealed these dyads have broad optical absorption in the ultraviolet and visible regions due to the complementary absorption of the two units. The differential scanning calorimetry traces and polarized optical microscopy textures showed all these dyads have columnar liquid crystal phases. Cyclic voltammetry revealed the highest occupied molecular orbitals of the dyads located on the porphyrin units, and the lowest unoccupied molecular orbitals located on the perylene units. In addition, these results were in agreement with that of the theoretical modeling. When excited at 423 or 473 nm, the photoluminescent emission spectra showed that the degree of fluorescence quenching of porphyrin units increased as the spacers became shorter. This quenching was ascribed to intramolecular photoinduced electron transfer, which also induced the dyad molecules to form the charge-separated states. The charge-separated molecules were further confirmed by the photocurrent response curves. These behaviors of broad absorption of the ultraviolet-visible light, yielding the charge-separated states of the molecules when excited and the formation of columnar liquid crystal phase made these dyads candidates for single-component photovoltaic active materials.
研究领域:
材料科学
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化学
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光子学
✓ 已验证
DOI
高影响因子
RSC Advances
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2018
·Vol. 8
·期 20
·11119-11126
·
IF 2.936
Faqin Tong,Shuangshuang Chen,Zhao Chen,Xuemin Lu,Qinghua Lu
Enhancing the azimuthal anchoring energy of the aligning film is a key requirement to improve the quality of liquid-crystal displays. Based on the assumption of mesogenic side groups being able to align liquid-crystal (LC) molecules, we have designed a novel transparent polyimide bearing cyanobiphenyl mesogenic side chains, which has a similar structure to that of liquid crystal 5CB. A pyrimidyl diamine monomer with a cyanobiphenyl mesogenic unit was first synthesized, and then co-polymerized with 4,4′-diaminodiphenyl ether and 4,4′-oxydiphthalic anhydride. The obtained polyimide (PI) exhibited good thermal stability and mechanical properties, as well as high optical transparency with transmittance of up to 86% in the wavelength range 450–700 nm. By evaluating the adhesion force between PI films and LCs with a super-sensitive microelectro-mechanical balance system, we have verified that appending mesogenic groups on the side chains of PI strengthens intermolecular interactions between the LC and PI surfaces, thereby enhancing the surface anchoring energy. Compared with the unmodified PI, the anchoring energy of the derivatized PI was improved more than 2.2-fold. By virtue of its good transparency and strong anchoring energy, this PI would seem to be an ideal candidate as a LC alignment film, and the concept of mesogens aligning LCs may open a new door in the design of LC alignment films.
研究领域:
材料科学
·
显示技术
✓ 已验证
DOI
PubMed
高影响因子
LIQUID CRYSTALS
·
2019
·
IF 3.078
Duo Wang,Yuan-Yuan Quan,Qing-Qing He,Ji-Wen Hu,Mei Tian,Ying-Gang Jia,Dan-Shu Yao
Two series of novel four-arm azobenzene liquid crystal molecules were designed and synthesized, and their mesophase properties, photo-induced transition were studied. Two series of mesogenic arms were screened with different length of flexible chain (the carbon number n of flexible chain is 4, 6, 8, 10) using methoxy and nitro as terminal substituents R. The four-arm azobenzene LCs were synthesized by introducing the mesogenic arms into cholic acid. FACAE-O-n, FACAE-N-n all belonged to photosensitive thermotropic enantiotropicnematic LCs. For methoxyl series, melting transitions (Tm), liquid crystal-isotropic transitions (Ti) and mesogenic ranges decreased with the increase of carbon numbers in flexible chain both on heating and cooling. The mesophase performance of FACAE-O-4 was the most excellent. For nitro series, Tm and Ti on heating and cooling decreased with the increase of carbon numbers. Nevertheless, mesogenic ranges increased with the increase of carbon numbers only on heating. The cooling mesogenic ranges showed a trend of rising firstly and then falling, reaching the maximum 103.1oC (n=8). Under ultraviolet irradiation, there was no red shift. The intensity of maximum absorption has changed with the increase of ultraviolet irradiation time. After photo-induced, Tm and Ti on heating and cooling of the four-arm LCs decreased, and the mesogenic ranges became shorter.
研究领域:
材料化学
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液晶研究
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有机合成
✓ 已验证
DOI
高影响因子
LIQUID CRYSTALS
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2019
·
IF 3.078
Xiaodong Wang,Lu Bai,Shengwen Kong,Ying Song,Fanbao Meng
Series of novel star-shaped liquid crystals containing [1,1ʹ-biphenyl]-4,4ʹ-diyl diisonicotinate mesogens with various counterions (Br−, B-SO3−,C-SO3−,H2PO4−, BF4−) have been synthesized and characterized, which display a nematic phase. The molecular structures of the liquid crystals, thereof consisting of rod-like mesogens linked together by different long alkyl spacers to a small disc-like core of central benzene-1,3,5-triyl triisonicotinate, have been fully characterized by 1H NMR. Their thermal and supramolecular organization behaviours have been studied by combining polarized optical microscopy, differential scanning calorimetry and small-angle X-ray scattering. These investigations showed that the mesophase temperature range increased with increasing alkyl chain length and the clearing point decreased with increase of anion size. These star-shaped liquid crystals have a long and ordered molecular structure, the electron delocalization of the π-π stacking conjugation effect and the electrostatic attraction of ionic make them have good ferroelectric properties and ionic conductivity properties. The interest in preparing ionic liquid crystal with a nematic phase lies in the technological applications as it is well known that the nematic phase has the highest fluidity of all liquid crystalline phases and hence the possibility to align it by applying an external electric/magnetic field, commonly used in electro-optical devices.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2021
·
IF 8.128
Zhaoqi Ye,Yang Zhao,Hongbin Zhang,Zhangping Shi,He Li,Xue Yang,Lei Wang,Lingtao Kong,Chunna Zhang,Zhizheng Sheng,Yahong Zhang,Yi Tang
Hypothesis It is a Holy Grail to realize the goal-oriented synthesis of zeotype crystals via direct thermodynamic/kinetic control of crystallization in the simplest inorganic system. Especially, the most commonly used counter cations (i.e., Na + and K + ) are in turn believed to play merely the role of balancing charges and stabilizing frameworks, which make the simple ion-based morphology/porosity control remain big challenges. Experiments We re-examined the role of Na + and K + to fine-tune the classical/nonclassical crystallization process in a seed-induced system with the simplest composition (Si/Al sources, inorganic alkali, and H 2 O), and proposed an “ion switch” strategy. By analyzing the multiple growth curves, tracking the precursor evolution, and observing epitaxial crystallization behavior , a distinctive “ion switch”-worked nonclassical mechanism was uncovered. Findings By the “ion switch” strategy, ZSM-5 mesocrystals were fine-regulated with diverse architecture from single crystal to nanocrystallite assembly and intracrystal mesopore-enriched crystal. Such simple ions-controlled crystallization was achieved through microstructure heterogeneity of zeolitic building-blocks triggered by different counterions and their corresponding assembly behavior from oriented attachment to random deposition. Furthermore, this protocol can be extended to a wider H 2 O/SiO 2 range, mixed Na + /K + systems, and other alkali metal ions from Li + to Cs + , and ZSM-5 mesocrystals with extended morphologies can be obtained.
研究领域:
材料科学
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结晶学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Nanomaterials
·
2018
·Vol. 9
·期 1
·28
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IF 3.504
Xianghong He,Yaheng Zhang,Yu Fu,Ning Lian,Zhongchun Li
There are only a few inorganic compounds that have evoked as much interest as sodium yttrium fluoride (NaYF4). Its extensive applications in various fields, including transparent displays, luminescence coding, data storage, as well as biological imaging, demand the precise tuning of the crystal phase. Controlling the emergence of the desired α-phase has so far remained a formidable challenge, especially via a simple procedure. Herein, we represented a polyol-assisted fluoride ions slow-release strategy for the rational control of pure cubic phase NaYF4mesocrystals. The combination of fluorine-containing ionic liquid as a fluoride source and the existence of a polyalcohol as the reactive medium ensure the formation of uniform α-phase mesocrystallines in spite of a higher temperature and/or higher doping level.Keywords:polyol-assisted fluoride ions slow-release strategy;NaYF4mesocrystals;crystallographic phase control
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Coatings
·
2023
·Vol. 13
·期 1
·168
·
IF 3.4
Han Wu,Ying Jiang,Wenjing Hu,Sijing Feng,Jiusheng Li
To develop a high-performance additive that can meet different operating conditions, three liquid crystals (LCs) were developed as additives for a base oil. The structures and thermal stabilities of the obtained LCs were characterized by nuclear magnetic resonance (NMR), Fourier transform infrared (FT-IR) spectroscopy, mass spectroscopy (MS), and thermogravimetric analysis (TGA). The effects of mesogenic-phase temperature ranges on tribological properties were analyzed using differential scanning calorimetry (DSC) and polarized optical microscopy (POM). UMT-TriboLab friction and wear tester was used to study the friction-reducing properties of LCs. The width of wear marks was observed by a Contour GT-K 3D profiler to illustrate the anti-wear performance of LCs. The friction surface was characterized by scanning electron microscopy (SEM) and Raman spectroscopy. It was demonstrated that, in comparison with the base oil, the addition of LCs caused a remarkable reduction in the coefficient of friction (21.57%) and wear width (31.82%). In addition, LCs show better tribological abilities in the mesogenic-phase temperature ranges. According to the results, we demonstrated that LCs can be used as lubricant additives, especially for several operating conditions under specific temperatures.Keywords:liquid crystals;mesogenic-phase temperature ranges;lubricant additives;tribological property
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
LIQUID CRYSTALS
·
2014
·
IF 2.349
Fafu Yang,Jin Yuan,Congcong Li,Hongyu Guo,Xiaoyun Yan
Series of triphenylene derivatives with multiple NH groups 3a, 3b, 4a, 4b, 5a and 5b were designed and synthesised by simple procedures in high yields. Their structures were confirmed by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), mass spectrometry (MS) and elemental analysis. Their mesophase behaviours were studied by differential scanning calorimetry, polarising optical microscopy and X-ray diffraction. The triphenylene derivatives 3a and 3b with two NH groups and triphenylene derivatives 4a and 4b with three NH groups possess excellent mesomorphic properties. Compounds 4a and 4b exhibited wider mesophase than compounds 3a and 3b. Triphenylene derivatives 5a and 5b with five NH groups have no mesomorphic properties. These results suggested the units of hydrogen bonds played the crucial roles on mesomorphic properties and acylthiosemicarbazide group with three NH groups was a good functional group for producing excellent mesomorphic properties.
研究领域:
材料化学
·
物理化学
✓ 已验证
DOI
高影响因子
MOLECULAR CRYSTALS AND LIQUID CRYSTALS
·
2015
·
IF 0.493
Kun Hu,Pei Chen,Xinbing Chen,Zhongwei An
A series of bithiophene-based compounds, 2-(5′-alkyl-2,2′-bithiophene-5-yl)-benzoxazole derivatives (nTBx), bearing different substituents (H, CH3, Cl, NO2) at the 5-position, were prepared and characterized. They exhibit enantiotropic mesophases with temperature ranges of 3°C–61°C and 4°C–71°C during heating and cooling, and nTBx with electron-withdrawing substituents (NO2, Cl) display higher clearing temperatures and wider mesophase ranges than those of corresponding homologues with electron donating substituents. Compared to biphenyl-based analogs (nB-x), nTBx show much larger red-shifted absorption bands (374–388 nm) and photoluminescence emission peaks (453–458 nm), thereby illustrating the impact of the bithiophene core on electronic properties originating from the π-molecular orbitals.
研究领域:
材料科学
·
有机化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）