Azobenzene-containing liquid crystalline block copolymer supramolecular complexes as a platform for photopatternable colorless materials

2020 ◽  
Vol 8 (4) ◽  
pp. 1225-1230
Author(s):  
Miron Bugakov ◽  
Natalia Boiko ◽  
Sergey Abramchuk ◽  
Xiaomin Zhu ◽  
Valery Shibaev
Keyword(s):  
Block Copolymer ◽  
Triblock Copolymer ◽  
Liquid Crystalline ◽  
Polarized Light ◽  
Supramolecular Complexes ◽  
Linearly Polarized ◽  
Hydrogen Bonded

Using liquid crystalline triblock copolymer complexes with hydrogen-bonded azobenzene moieties, photopatterned colorless birefringent films were prepared by irradiation with linearly polarized light and subsequent extracting azobenzene moieties.

Hierarchical nanostructures of a liquid crystalline block copolymer with a hydrogen-bonded calamitic mesogen

Polymer ◽  
2019 ◽  
Vol 182 ◽  
pp. 121835 ◽  
Author(s):  
Hongbing Pan ◽  
Anqi Xiao ◽  
Wei Zhang ◽  
Longfei Luo ◽  
Zhihao Shen ◽  
...  
Keyword(s):  
Block Copolymer ◽  
Liquid Crystalline ◽  
Hierarchical Nanostructures ◽  
Hydrogen Bonded

scholarly journals Thermocapillary Marangoni Flows in Azopolymers

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2464
Author(s):  
Andrzej Miniewicz ◽  
Anna Sobolewska ◽  
Wojciech Piotrowski ◽  
Pawel Karpinski ◽  
Stanislaw Bartkiewicz ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Mass Movement ◽  
Polymer Surface ◽  
Polarized Light ◽  
Marangoni Effect ◽  
Mass Motion ◽  
Polymeric Liquid ◽  
Force Microscopy ◽  
Atomic Force ◽  
Linearly Polarized

It is well known that light-induced multiple trans-cis-trans photoisomerizations of azobenzene derivatives attached to various matrices (polymeric, liquid crystalline polymers) result in polymer mass movement leading to generation of surface reliefs. The reliefs can be produced at small as well as at large light intensities. When linearly polarized light is used in the process, directional photo-induced molecular orientation of the azo molecules occurs, which leads to the generation of optical anisotropy in the system, providing that thermal effects are negligible. On the other hand, large reliefs are observed at relatively strong laser intensities when the optofluidization process is particularly effective. In this article, we describe the competitive thermocapillary Marangoni effect of polymer mass motion. We experimentally prove that the Marangoni effect occurs simultaneously with the optofluidization process. It destroys the orientation of the azopolymer molecules and results in cancelation of the photo-induced birefringence. Our experimental observations of polymer surface topography with atomic force microscopy are supported by suitable modelings.

Laser manipulation in liquid crystals: an approach to microfluidics and micromachines

2006 ◽  
Vol 364 (1847) ◽  
pp. 2789-2805 ◽  
Author(s):  
Helen F Gleeson ◽  
Tiffany A Wood ◽  
Mark Dickinson
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Polarized Light ◽  
Three Dimensions ◽  
Laser Tweezers ◽  
Fluid Medium ◽  
Circularly Polarized Light ◽  
Viscosity Coefficients ◽  
Linearly Polarized ◽  
Local Shear

Laser trapping of particles in three dimensions can occur as a result of the refraction of strongly focused light through micrometre-sized particles. The use of this effect to produce laser tweezers is extremely common in fields such as biology, but it is only relatively recently that the technique has been applied to liquid crystals (LCs). The possibilities are exciting: droplets of LCs can be trapped, moved and rotated in an isotropic fluid medium, or both particles and defects can be trapped and manipulated within a liquid crystalline medium. This paper considers both the possibilities. The mechanism of transfer of optical angular momentum from circularly polarized light to small droplets of nematic LCs is described. Further, it is shown that droplets of chiral LCs can be made to rotate when illuminated with linearly polarized light and possible mechanisms are discussed. The trapping and manipulation of micrometre-sized particles in an aligned LC medium is used to provide a measure of local shear viscosity coefficients and a unique test of theory at low Ericksen number in LCs.

Star-shaped triphenylene discotic liquid crystalline oligomers and their hydrogen-bonded supramolecular complexes with simple acids

2015 ◽  
Vol 3 (44) ◽  
pp. 11735-11746 ◽  
Author(s):  
Ke-Qing Zhao ◽  
Xiao-Yan Bai ◽  
Bo Xiao ◽  
Yue Gao ◽  
Ping Hu ◽  
...  
Keyword(s):  
Self Assembly ◽  
Liquid Crystalline ◽  
Supramolecular Complexes ◽  
Discotic Mesogens ◽  
Hydrogen Bonded

The synthesis and self-assembly properties of four novel star-shaped oligomers containing triphenylene discotic mesogens are reported.

scholarly journals Phase Behavior and DFT Calculations of Laterally Methyl Supramolecular Hydrogen-Bonding Complexes

Crystals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 133 ◽  
Author(s):  
Hoda Ahmed ◽  
Mohamed Hagar ◽  
Omaima Alhaddad
Keyword(s):  
Differential Scanning Calorimetry ◽  
High Stability ◽  
Polarized Light ◽  
Supramolecular Complexes ◽  
Scanning Calorimetry ◽  
Methyl Group ◽  
Smectic C ◽  
Computational Calculations ◽  
Nematic Phases ◽  
Hydrogen Bonded

Four new series of laterally methyl-substituted hydrogen-bonded supramolecular complexes were prepared. The prepared complexes were thermally investigated by differential scanning calorimetry (DSC) and phases identified by polarized light microscopy (PLM). Supramolecular hydrogen-bonded complexes formed from a 1:1 mixture of any two derivatives, bearing different alkoxy chains, of 4-alkoxyphenylazobenzoic acid and 4-(2-(pyridin-4-yl)diazenyl-(2-(or 3-)methylphenyl) 4-alkoxybenzoate. The investigated 1:1 mixture made by introducing a lateral methyl group by different spatial orientation angles into pyridine-based components. All new complexes were confirmed by Fourier-transform infrared spectroscopy (FTIR) and computational calculations used to study their stabilities. It is found that the prepared complexes are dimorphic, exhibiting smectic C and enhanced nematic phases. A comparison was made between the new series and previously investigated simpler complexes, revealed that the incorporation of the phenylazo group elongate the mesogenic part and hence broad nematic phases were obtained with high stability.

Hierarchically ordered nanostructures of a supramolecular rod-coil block copolymer with a hydrogen-bonded discotic mesogen

2019 ◽  
Vol 10 (8) ◽  
pp. 991-999 ◽  
Author(s):  
Hongbing Pan ◽  
Wei Zhang ◽  
Anqi Xiao ◽  
Xiaolin Lyu ◽  
Pingping Hou ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Block Copolymer ◽  
Block Copolymers ◽  
Liquid Crystalline ◽  
Hierarchical Structures ◽  
Molar Ratio ◽  
Ordered Nanostructures ◽  
Hydrogen Bonded

Supramolecular liquid crystalline block copolymers prepared via hydrogen bonding exhibit hierarchical structures that can be tuned by varying the molar ratio of the discotic hydrogen-bonding acceptor to the block copolymer donor.

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