1352742-56-3Relevant articles and documents
Azobenzene-based supramolecular liquid crystals: The role of core fluorination
Alaasar, Mohamed,Darweesh, Ahmed F.,Schmidt, Jaques-Christopher,Tschierske, Carsten
, (2020)
The impact of core fluorination on the phase behaviour of supramolecular hydrogen-bonded liquid crystals (HBLCs) is investigated in detail. Therefore, different types of HBLCs were synthesized using two benzoic acid derivatives as proton donors, namely, 4-octyloxybenzoic acid and octylbenzoic acid. The two acids were combined through intermolecular hydrogen-bonding with alkoxyazopyridine derivatives as proton acceptors. Three different types of azopyridines were used either without fluorine substitution or with one lateral fluorine substituent at different positions. The study proved the importance of using core fluorination as a significant tool to modify the liquid crystalline behaviour of HBLCs, where all azopyridines are non-mesomorphic and almost all their complexes exhibit enantiotropic mesophases. The formation of the hydrogen bond between the complementary components was confirmed using FTIR and 1H NMR spectroscopy, while the liquid crystalline self-assembly of the HBLCs was investigated in detail using polarized light microscope (PLM) and differential scanning calorimetry (DSC). Depending on the type of the terminal chain on the benzoic acid derivative and on the position of the lateral fluorine substituent different types of mesophases including nematic (N), smectic A (SmA) and smectic C (SmC) phases were observed. Finally, under UV light illumination all the prepared HBLCs show cis-trans photoisomerization resulting in tuning the liquid crystalline phases, which is of importance for industrial applications.
Janus ultrathin film from multi-level self-assembly at air-water interfaces
Zhang, Hongbin,Hao, Rui,Jackson, John K.,Chiao, Mu,Yu, Haifeng
, p. 14843 - 14846 (2014)
Ultrathin free-standing Janus films were fabricated at air-water interfaces using azopyridine derivatives and poly(acrylic acid) via multi-level self-assembly on molecular and microscopic scales, which showed distinct asymmetric water wetting abilities on
Photoresponsive halogen bonded polycatenar liquid crystals
Alaasar, Mohamed,Poppe, Silvio,Tschierske, Carsten
, p. 233 - 240 (2019)
Photosensitive liquid crystalline materials whose properties could be modified with UV–visible light irradiation are of special interest for photosensitive and photoswitching materials. Herein we represent the first examples of light-responsive halogen bonded supramolecular polycatenars. Photoswitchable liquid-crystalline aggregates were designed and prepared via halogen bond formation between a non-mesogenic taper shaped tetrafluoroiodobenzene based halogen bond-donor and non-mesogenic or mesogenic azopyridine derivatives as halogen bond-acceptors. The liquid crystalline behaviour of the prepared materials was characterized by differential scanning calorimetry (DSC), polarized optical microscope (POM) and X-ray diffraction (XRD). Upon irradiation with UV light, the complexes undergo fast and reversible photoinduced phase transition. Interestingly, some of these halogen-bonded polycatenars exhibit enantiotropic liquid crystalline phases over wide temperature ranges which are the widest among all previously reported photoresponsive perfluoroaryliodide based supramolecular halogen bonded liquid crystals.
Compound assisting metal in enhancing fluorescence and preparation method thereof
-
Paragraph 0014; 0015; 0016; 0040; 0041; 0048; 0050; 0051, (2017/01/02)
The invention provides a preparation method of a compound assisting metal in enhancing fluorescence. The preparation method includes following steps: 1), synthesizing silver nanoparticles in situ in dye containing pyridine group; 2), dissolving an obtaine
