Photopatterning of Azobenzene-Containing Liquid Crystalline Triblock Copolymers: Light-Induced Anisotropy and Photostabilization
| Autor: | M. A. Bugakov, Pasquale Pagliusi, Natalia Boiko, Valery Shibaev, Biagio Audia, Gabriella Cipparrone |
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| Rok vydání: | 2020 |
| Předmět: |
Materials science
Birefringence Polymers and Plastics Polymers Mesogen Organic Chemistry Supramolecular chemistry 02 engineering and technology Thermal treatment 010402 general chemistry 021001 nanoscience & nanotechnology Photochemistry 01 natural sciences 0104 chemical sciences Liquid Crystals Photochromism chemistry.chemical_compound Azobenzene chemistry Materials Chemistry Copolymer Anisotropy 0210 nano-technology Azo Compounds |
| Zdroj: | Macromolecular rapid communications. 41(20) |
| ISSN: | 1521-3927 |
| Popis: | Photochromic liquid crystalline block copolymers (PLCBCs) are currently playing a significant role as light-responsive materials because of their light controllable features over multiple length scales. Herein, a study of the photoinduced optical anisotropy derived by the combination of orientation phenomena at molecular and supramolecular levels in a novel kind of side-chain PLCBCs with mesogenic phenyl benzoate groups and pyridine units that is hydrogen bonded with azobenzene-containing phenol is reported. Based on the polymeric architectures and composition, the supramolecular configuration self-organizes in different microphases that affect the material response to the external stimuli. Simple, 1D, polarization holograms are recorded to evaluate the photoinduced birefringence. The first step, light patterning, involves the orientation of the azobenzene units and precedes a thermal treatment that amplifies the induced anisotropy through the cooperative orientation of the mesogenic units. By selective extraction, the azobenzene units can be removed, making the material transparent to the visible light. Excellent photostability of the material birefringence is obtained, whose final value is strongly affected by the block copolymer's architecture. The versatility in the molecular design, the fine control of the photoinduced features by external parameters, and, finally, the possibility to achieve photostability make these materials of great potential for developing optical and photonic devices. |
| Databáze: | OpenAIRE |
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