JOURNAL OF CHROMATOGRAPHY A
·
2023
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IF 4.1
Jiayu Yu,Jingdong Peng,Huanjun Peng,Zilong Zhang,Kun Fan,Pan Luo,Jiajia Wu,Hanqi Yang,Hanlin Zeng,Xiang Wang
Three structurally similar silane reagents with different terminal groups were prepared and bonded to silica to obtain three structurally similar stationary phases (Sil-Ph-COOH, Sil-Phe and Sil-Ph-NH 2 ). The prepared stationary phases were characterized through elemental analysis (EA) and Fourier Transform Infrared Spectroscopy (FT-IR). These three stationary phases provided acceptable retention repeatability (relative standard deviations between 0.08% and 0.13%) and high column efficiency (7.3 × 10 4 plates/m for uridine on Sil-Phe). The retention behavior of the three columns was investigated under different chromatographic conditions including different mobile phase ratio, salt concentration, pH etc. The retention mechanisms were explored by linear solvation energy relationships and Van't Hoff plots. Applications in separation under reversed phase liquid chromatography (RPLC), hydrophilic interaction liquid chromatography (HILIC) and ion exchange chromatography (IEC) mode were investigated. The results showed that the retention capacity of the stationary phases with different terminal groups to the analytes is very different, especially for carboxylic acids, because the surface charges of amino groups and carboxyl groups under weakly acidic conditions produce different electrostatic effects with dissociated carboxylic acids. Finally, the Sil-Phe column was employed to detect ibuprofen extracted from pharmaceutical ibuprofen capsules and vitamins extracted from vitamin tablets.
研究领域:
分析化学
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色谱学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2024
·
IF 5.3
Ran Chen,Junyu Zou,Zihao Mao,Zhongwei An,Pei Chen,Xinbing Chen
Laser display technology can enhance the image quality of liquid–crystal on silicon (LCoS) devices in AR displays. High birefringence (Δ n ), large dielectric anisotropy (Δ ε ), low rotational viscosity ( γ 1 ) and good blue-light stability are inevitable performance requirements for achieving fast response time, low voltage and 2π phase modulation in LCoS devices based on laser display technology. However, people lack attention to how to obtain liquid crystal compounds with above properties. In this work, we propose to utilize one fluorinated terphenyl unit with excellent blue-light stability as the molecular skeleton, and then employ large polar terminal groups to modulate the molecular polarizability and dipole moment , and finally screen to obtain the LCs with high Δ n and large Δ ε . The effects of methyl, fluorinated, chlorinated and cyano terminal groups on the mesomorphic and electro-optical properties of fluorinated terphenyl LCs were systematically studied. Experimental and theoretical results show that the target compounds exhibit wide LC phase intervals, and could enhance the Δ n , Δ ε of the parent LC mixture and reduce its viscoelastic constant, further meaning that they would help to improve the electro-optical properties of LC mixtures for AR displays. Our results would provide experimental data and technical support for the future development of LC mixtures with high blue-light stability for AR displays.
研究领域:
材料科学
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光学
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显示技术
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产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2015
·Vol. 3
·期 33
·8706-8711
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IF 4.696
Ran Chen,Yi Jiang,Jian Li,Zhongwei An,Xinbing Chen,Pei Chen
Four series of 1,3-dioxolane-terminated liquid crystals were prepared via multi-step reactions based on 4-alkylcyclohexanecarboxylic acids. Their structures were confirmed by infrared spectrometry (IR), nuclear magnetic resonance (NMR) and mass spectrometry (MS). Their properties were measured by differential scanning calorimetry (DSC), polarising optical microscopy (POM), X-ray diffraction (XRD), Abbe refractometer and an electrical constants instrument. The results show that the positive dielectric anisotropy and birefringence of the tolane-liquid crystals are increased significantly by an introduction of 1,3-dioxolane as a terminal group. The application of the 1,3-dioxolane-terminated liquid crystals in the mixture was investigated and the results show that lower threshold voltage, wider nematic range and higher birefringence are obtained when compared to the mixture containing liquid crystals with buty-3-enyl as a terminal group. The lateral fluoro substituent, alkyne-bridge and 1,3-dioxolane terminal group enhance the stability of the nematic mesophase and the solubility of the corresponding compounds in the common host liquid crystal mixture. Meanwhile, DFT calculations of dipole moments and molecular polarizabilities were used to correlate the experimental findings.
研究领域:
材料科学
·
化学
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产品关联
DOI
高影响因子
HIGH PERFORMANCE POLYMERS
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2016
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IF 1.045
Shanyou Liu,Shiyang Zhu,Xueping Wang,Haiwei Tan,Shaowei Guan
To investigate the effect of terminal groups on the properties of hyperbranched polyimides (HBPIs) for potential optical applications, a series of HBPIs bearing different terminal groups have been synthesized through a novel aromatic CF3-containing tetra-amine, 4,4′-di[3,5-di(2-trifluoromethyl-4-aminophenoxy)phenoxy] sulfone, and a long chain dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]hexafluoropropane, via a two-step polycondensation procedure. The synthesized HBPIs could form flexible and tough polyimide (PI) films, which exhibit good thermal stability with the glass transition temperatures of 191–234°C for differential scanning calorimetry measurement, the 5% weight loss temperatures of 533–610°C, and residual weights of 45.8–58.6% at 800°C under nitrogen atmosphere. The PI films have favorable mechanical properties with tensile strengths of 77–92 MPa, elongation at break of 3.55–7.99%, and initial modulus of 2.05–2.86 GPa. The films also exhibit the good transmittance of higher than 80% at 800 nm. The average refractive indices (nav) and in-plane/out-of-plane birefringence (Δn) measured at 632.8 nm are in the range of 1.5539–1.6022 and 0.0065–0.0077, respectively. The good transmittance in the visible region, tunable nav, and low Δn are very suitable for optical applications.
研究领域:
材料科学
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高分子化学
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光学材料
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DOI
高影响因子
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