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Synthesis and Liquid Crystalline Behavior of Side Chain Liquid Crystalline Polymers Containing Triphenylene Discotic Mesogens with Different Length Flexible Spacers

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Chinese Journal of Polymer Science 2015年第9期33卷 1245-1259页

作者： Jian-feng Ban 陈盛张海良 Key Laboratory of Polymeric Materials and Application Technology of Hunan Province Key Laboratory of Advanced Functional Polymer Materials of Colleges and Universities of Hunan Province College of Chemistry Xiangtan University

A series of side chain liquid crystalline polymers （SCLCPs） containing triphenylene （Tp） units in the side chains, denoted as PMTS （without spacer） and PMTnS （n = 2, 3, 4, 6, which is the number of the methylene units between the main chain and Tp moieties in the side chains）, with different lengths of spacers were synthesized through conventional free radical polymerization. The chemical structures of the monomers were confirmed by 1H/IaC-NMR, and the phase behaviors were examined by differential scanning calorimetry （DSC）, polarized optical microscopy （POM） and wide-angle X-ray diffraction （1D and 2D WAXD）. The molecular characterization of the polymers was performed with 1H-NMR, gel permeation chromatography （GPC） and thermogravimetric analysis （TGA）. The phase behaviors of the polymers have been investigated by a combination of techniques including DSC, POM, 1D and 2D WAXD. The results showed that the length of spacer has significant effects on the LC phase behavior of polymers. For PMTS and PMT2S, they displayed the columnar phase developed by the Tp moieties and the main chain as a whole due to the strong coupling effect of the Tp moieties and the main chain. For the PMT3S, PMT4S and PMT6S, they formed the symmetry hexagonal columnar （~n） phase owing to the decoupling effect. All of these indicated that the ＂decoupling effect＂ or ＂coupling effect＂ depended on the length of spacers, leading to the different LC phase formation mechanism.

关键词： Liquid crystalline polymer Triphenylene Flexible spacer Phase behavior Columnar phase.

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Synthesis,Characterization and Phase Behaviors of Polypeptides Bearing Biphenyl Mesogens and Oligo-Ethylene-Glycol Tails

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Chinese Journal of Polymer Science 2015年第8期33卷 1150-1161页

作者： Qiu-lin Yuan Wen-jun Liu Yong Deng Ying Ling 唐浩宇 Key Laboratory of Polymeric Materials and Application Technology of Hunan Province Key Laboratory of Advanced Functional Polymer Materials of Colleges and Universities of Hunan ProvinceCollege of ChemistryXiangtan University

A series ofpolypeptides bearing biphenyl mesogenic side-chains and oligo-ethylene-glycol （OEG） tails （PPLGn-g- BPOEGm, n = 26 and 63, m = 2, 3, and 7） has been synthesized via a 1,3-dipolar cycloaddition with quantitative grafting density. FTIR results revealed that the polypeptides adopted highly stable a-helix in the temperature range of 25-200 ℃. DSC, POM and WAXS analysis revealed that PPLGn-g-BPOEGm （m ≤ 3） samples with short OEG tail length showed two main phase transitions including crystal to liquid crystalline （smectie C, SmC） phase transition and the melting transition of crystalline E-phase, while PPLG,-g-BPOEG7 with longer OEG tail length （m = 7） exhibited the melting transitions without the formation of liquid crystalline phase.

关键词： Liquid-crystalline polymers Polypeptides Click chemistry Smectic phases.

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Multiple Effects Tailoring the Self-organization Behaviors of Triphenylene Side-chain Liquid Crystalline Polymers via Changing the Spacer Length

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Chinese Journal of Polymer Science 2018年第8期36卷 960-969页

作者： Xiang-Hui Han Xi-Wen Yang Sheng Chen Hang Luo Dou Zhang Hai-Liang Zhang Key Laboratory of Polymeric Materials and Application Technology of Hunan Province Key Laboratory of Advanced Functional Polymer Materials of Colleges and Universities of Hunan ProvinceCollege of ChemistryXiangtan University State Key Laboratory of Powder Metallurgy Central South University

Long-alkyl tail triphenylene （TP） side-chain liquid crystalline polymers （SCLCPs） with different spacer length （P-m-TP, m = 2, 3, 4, 6, 8, which is the number of carbon atom in the flexible alkyl spacers） have been successfully synthesized via free radical polymerization. The differential scanning calorimetry （DSC）, polarized light microscopy （POM）, ultraviolet-visible spectroscopy （UV- Vis）, wide-angle X-ray diffraction （WAXD） and small-angle X-ray scattering （SAXS） measurements were performed to investigate the influence of multiple effects on the self-organization behaviors of P-m-TP, including steric effect, decoupling effect and π-π stacking effect. The experimental results revealed that P-m-TP （m = 2, 3, 4） formed the columnar phase which was developed by the TP moieties and the main chain as a whole, suggesting that the side-chains had strong steric effect even though the number of spacer length （m） exceeded 4. In addition, the clearing points （Tis） of the polymers were above 300 ℃. When m = 6 and 8, the polymers displayed hexagonal columnar phase and exhibited the low Tis （91 and 80 ℃ respectively）, originating from the self-assembly of triphenylene due to the decoupling effect and π-π stacking effect. This work offers a viable and inspiring pathway to control the phase transition temperature and phase structure ofTP SCLCPs via simply tailoring the spacer length and increasing the alkyl tail length of TP.

关键词： Polymer synthesis Side-chain liquid crystalline polymers Phase structure Steric effect

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High temperature mechanical retention characteristics and oxidation behaviors of the MoSi2（Cr5Si3）–RSiC composites prepared via a PIP-AAMI combined process

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Journal of Advanced Ceramics 2019年第2期8卷 196-208页

作者： Peng-zhao GAO Lei CHENG Zheng YUAN Xiao-pan LIU Han-ning XIAO College of Materials Science and Engineering Hunan UniversityChangsha 410082China Hunan Province Key Laboratory for Advanced Carbon Materials and Applied Technology Hunan UniversityChangsha 410082China Hunan Province Key Laboratory for Spray Deposition Technology and Application Hunan UniversityChangsha 410082China

In the present paper,MoSi2(Cr5Si3)–RSiC composites were prepared via a combination of precursor impregnation pyrolysis(PIP) and MoSi2-Si-Cr alloy active melt infiltration(AAMI) process. Composition, microstructure, mechanical retention characteristics, and oxidation behaviors of the composites at elevated temperature were studied. X-ray diffraction(XRD) pattern confirms that the composites mainly compose of 6 H–SiC, hexagonal MoSi2, and tetragonal Cr5Si3. Scanning electron microscopy(SEM) image reveals that nearly denseMoSi2(Cr5Si3)–RSiC composites exhibiting three-dimensionally(3D) interpenetrated network structure are obtained when infiltrated at 2173 K, and the interface combination of the composites mainly depends on the composition ratio of infiltrated phases. Oxidation weight gain rate of the composites is much lower than that of RSiC matrix, where MoSiCr2 possesses the lowest value of 0.1630 mg×cm-2, about 78% lower than that of RSiC after oxidation at 1773 K for 100 h. Also, it possesses the highest mechanical values of 139.54 MPa(flexural strength σf and RT) and 276.77 GPa(elastic modulus Ef and RT), improvement of 73.73% and 29.77% as compared with that of RSiC, respectively. Mechanical properties of the composites increase first and then decrease with the extension of oxidation time at 1773 K, due to the cooperation effect of surface defect reduction via oxidation reaction and thermal stress relaxation in the composites, crystal growth, and thickness increase of the oxide film. Fracture toughness of MoSiCr2 reaches 2.24 MPa·m1/2(1673 K), showing the highest improvement of 31.70% as compared to the RT value.

关键词： MoSi2(Cr5Si3)–RSiC composites precursor impregnation pyrolysis and MoSi2-Si-Cr alloy active melt infiltration (PIP-AAMI) high temperature mechanical characteristic oxidation behavior

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Syntheses and cofluorescence of complexes of Eu(Ⅲ)/Y(Ⅲ) with terephthalic acid, 2-thenoyltrifluoroacetone and trioctylphosphine oxide

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中国有色金属学会会刊：英文版 2007年第3期17卷 638-643页

作者：赵学辉黄可龙刘素琴焦飞鹏刘志国胡舜钦李朝建 School of Chemistry and Chemical Engineering Central South University Key Laboratory of Green Packaging and Application Biological Nanotechnology of Hunan Province Hunan University of Technology

A series of Eu( Ⅲ )/Y( Ⅲ ) complexes of terephthalic acid(TPA) with 2-thenoyltrifluoroacetone(HTTA) and trioctylphosphine oxide(TPPO) were synthesized. Compositions of these complexes are revealed to be Eu2(1-x)Y2x(TPA)(TTA)4- (TPPO)4 or Eu1-xYx(TPA)(TTA)(TPPO)2. Their IR spectra, fluorescent spectra and the thermal and optical stability were studied. The fluorescent excitation spectra of these complexes show more broad excitation bands than those of Eu2(TPA)3(TPPO)4 and Eu(TTA)3(TPPO)2 corresponding to their formations. In addition, both the binuclear complex EuY(TPA)(TTA)4(TPPO)4 and the chain complex Eu0.4Y0.6(TPA)(TTA)(TPPO)2 present higher thermal stability and better optical stability than the mononuclear complex Eu(TTA)3(TPPO)2 does. And their thermal and optical stabilities are preferably interpreted from the binuclear structure together with the chain polynuclear structure of the complexes. The fluorescence enhancement of cofluorescence Y3+ ions to the Eu(Ⅲ) complexes is clear. The optimum content of Y3+ is 0.6 (molar fraction) for the chain complexes Eu1-xYx(TPA)(TTA)- (TPPO)2 and 0.5 for the binuclear complexes Eu2(1-x)Y2x(TPA)(TTA)4(TPPO)4. The formation of polynuclear structure of the complex Eu1-xYx(TPA)(TTA)(TPPO)2 appears to be responsible for the good cofluorescence effect of Y3+ ions.

关键词：铕元素对酞酸 2-噻吩甲酰基三氟丙酮合成方法

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An unconventional phase field modeling of domains formation and evolution in tetragonal ferroelectrics

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Science China(Technological Sciences) 2016年第7期59卷 1059-1064页

作者： ZHOU YouGang PENG JinLin PAN Kai LIU YunYa Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education and Key Laboratory of Materials Design and Preparation Technology of Hunan Province School of Materials Science and Engineering Xiangtan University

Based on characteristic functions of variants, we developed an unconventional phase field modeling for investigating domains formation and evolution in tetragonal ferroelectrics. In order to develop this computational approach, we constructed the anisotropy energy of tetragonal variants, which is used instead of Landau-Devonshire potential in the conventional phase field method, resulting in that much fewer parameters are needed for simulations. This approach is advantageous in simulations of emerging ferroelectric materials. We employ it to study the formation and evolution of domains in tetragonal barium titanate single crystal, as well as the nonlinear behaviors under cyclical stress and electric field loading. A multi-rank laminated ferroelectric domain pattern, 90° domain switching accompanied by polarization rotation, and 180° domain switching accompanied by move of domain wall are predicted. It is found that the speed of 90° domain switching is slower than that of 180° domain switching, due to both polarization and transformation strain changed in 90° domain switching. It also suggests that large strain actuation can be generated in single crystal ferroelectrics via combined electromechanical loading inducing 90° domain switching. The good agreement between simulation results and experimental measurements is observed.

关键词： phase field simulation ferroelectric domains formation and evolution ferroelectric materials

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Progress on sensors based on nanomaterials for rapid detection of heavy metal ions

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Science China Chemistry 2017年第3期60卷 329-337页

作者： Yuan Liu Yan Deng Hongming Dong Keke Liu Nongyue He Economical Forest Cultivation and Utilization of 2011 Collaborative Innovation Center in Hunan Province Hunan Key Laboratory of Green Chemistry and.Application of Biological NanotechnologyHunan University of Technology State Key Laboratory of Bioelectronics Southeast University

The heavy metal ions,especially Cd^(2+),Pb^(2+) and Hg^(2+),show extremely hazard to the environment and human *** measurement of heavy metal ions using sensors is catching more and more attention for its advantages of high sensitivity and selectivity,low-cost,convenience to handle and rapid *** recent years,nanomaterials such as gold nanoparticles(NPs),magnetic nanoparticles,graphene and nanocomposite materials are applied in sensors for improving sensitivity and selectivity,making the research on electrochemical(EC) sensors,spectrometric biosensors and colorimetric biosensors become a hot spot in the application to investigate heavy metal ions,in particular,Cd^(2+),Pb^(2+) and Hg^(2+).In this short review,the research of advanced detection of Cd^(2+),Pb^(2+) and Hg^(2+) and its progress based on nanomaterial sensors in recent years is reviewed.

关键词： heavy metal ions sensors nanomaterials detection progress

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Effects of spin-coating speed on the morphology and photovoltaic performance of the diketopyrrolopyrrole-based terpolymer

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Science China Chemistry 2016年第4期59卷 466-471页

作者： Fen Wu Rongyan Hou Liang Yang Bin Zhao Songting Tan Key Laboratory of Environmentally Friendly Chemistry and Applications Ministry of Education College of Chemistry Xiangtan University Key Laboratory of Polymeric Materials & Application Technology of Hunan Province Xiangtan University

Polymer solar cells(PSCs) were fabricated by combining a diketopyrrolopyrrole-based terpolymer(PTBT-HTID-DPP) as the electron donor, and [6,6]-phenyl C_(61) butyric acid methyl ester(PC_(61)BM) as the electron acceptor, and the power conversion efficiency(PCE) of 4.31% has been achieved under AM 1.5 G(100 m W cm^(-2)) illumination condition via optimizing the polymer/PC_(61)BM ratio, the variety of solvent and the spin-coating speed. The impact of the spin-coating speed on the photovoltaic performance of the PSCs has been investigated by revealing the effects of the spin-coating speed on the morphology and the absorption spectra of the polymer/PC_(61)BM blend films. When the thickness of the blend films are adjusted by spin-coating a fixed concentration with different spin-coating speeds, the blend film prepared at a lower spin-coating speed shows a stronger absorption per unit thickness, and the correspond device shows higher IPCE value in the longer-wavelength region. Under the conditions of similar thickness, the blend film prepared at a lower spin-coating speed forms a more uniform microphase separation and smaller domain size which leads to a higher absorption intensity per unit thickness of the blend film in long wavenumber band, a larger short-circuit current density(J_(sc)) and a higher power conversion efficiency(PCE) of the PSC device. Noteworthily, it was found that spin-coating speed is not only a way to control the thickness of active layer but also an influencing factor on morphology and photovoltaic performance for the diketopyrrolopyrrole-based terpolymer.

关键词： polymer solar cells device optimization spin-coating speed morphology absorption per unit thickness

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Syntheses and applications of Eu(Ⅲ) complexes of 2-thienyltrifluoroacetonate, terephthalic acid and phenanthroline as light conversion agents

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Journal of Central South University of technology 2007年第1期14卷 62-67页

作者：赵学辉黄可龙焦飞鹏杨幼平李朝建刘志国胡舜钦 School of Chemistry and Chemical Engineering Central South University Key Laboratory of Green Packaging and Application Biological Nanotechnology of Hunan Province Hunan University of Technology

A series of europium（Ⅲ） complexes of 2-thienyltrifluoroacetonate （HTTA）, terephthalic acid （TPA） and phenanthroline （Phen） were synthesized. The new complexes Eu（TPA）（TTA）Phen and EUE（TPA）（TTA）4Phen2 were characterized by elemental analysis, IR spectrum, scanning electron microscope and thermal stability analysis. The results show that the thermal stability of the Eu（Ⅲ） complexes increases in the following order： the mononuclear complex Eu（TTA）3Phen, the binuclear complex EUE（TPA）（TTA）4Phen2, the chain polynuclear complex Eu（TPA）（TTA）Phen. And the formation of the binuclear/polynuclear structure of the new complexes appears to be responsible for the enhancement of their thermal and optical stability. In addition, The fluorescence excitation spectra of these new complexes show more broad excitation bands than that of the complex Eu（TTA）3Phen corresponding to their formation. The enhancement of Eu^3＋ fluorescence in the new complexes can be observed by the addition of Gd^3＋. The bright red luminescent plastics can be obtained when the complex EuGd（TPA）（TTA）4Phen2 is added above 0.5% （mass fraction）.

关键词： fluorescent properties europium terephthalic acid 2-thienyltrifluoroacetonate

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Strain engineering on electrochemical performance sensing of uric acid based on two-dimensional Co 3 O 4 nanosheets

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Sensors and Actuators B: Chemical 2025年

作者： He Liu Feng Lin Xuejun Zheng Hui Dong School of Mechanical Engineering and Mechanics Engineering Research Center of Complex Tracks Processing Technology and Equipment of MoE Xiangtan University Xiangtan 411105 China Key Laboratory of Welding Robot and Application Technology of Hunan Province Xiangtan University Xiangtan 411105 China

Two-dimensional (2D) nanostructured semiconductors with abundant active sites and specific surface area are promising non-precious metal catalysts for flexible electrochemical biosensors. Here, we reported the cost-effective and high-performance strain electrocatalytic uric acid (UA) sensors based on 2D Co 3 O 4 nanosheets prepared by a simple hydrothermal method. The corresponding electrocatalytic efficiencies for UA were modulated by tensile and compressive strains. Moreover, density functional theory (DFT) calculations were performed to reveal the corresponding mechanisms from the atomic scale. The prepared UA strain sensor exhibits a wide detection concentration with a linear range from 6 μM to 5 mM and a low detection limit of ~6 μM. The induced compressive strain of -1.5% in the 2D Co 3 O 4 nanosheet significantly increases the sensitivity by 58.4% and decreases the charge transfer impedance by 29.7% of UA, while the tensile strain of +1.5% decreases the sensitivity by 52.4% and increases the charge transfer impedance by 44.7% of UA compared to those under zero strain. From DFT calculation, the corresponding compressive strain of -1.5% decreases the spin-up band gap by 23.9% and the spin-down band gap by 24.6% and the tensile strain of +1.5% leads to the increase of 30.2% in the spin-up band gap and 48.4% in the spin-down band gap as to those of intrinsic zero strain. The decrease in bandgap leads to an increase in the electron transport rate, thus increasing the sensor sensitivity. Our research provides guidance on the design of low-cost and mass-producible 2D materials integrated into wearable high-performance electrocatalytic sensors.

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