Otaki M, Kumai R, Sagayama H, Goto H. Synthesis of Polyazobenzenes Exhibiting Photoisomerization and Liquid Crystallinity.
Polymers (Basel) 2019;
11:E348. [PMID:
30960332 PMCID:
PMC6419163 DOI:
10.3390/polym11020348]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 02/09/2019] [Accepted: 02/12/2019] [Indexed: 11/17/2022] Open
Abstract
While only a few studies have investigated the synthesis of main chain-type polyazobenzenes, they continue to draw an increasing amount of attention owing to their industrial applications in holography, dyes, and functional adhesives. In this study, dibromoazobenzene was prepared as a monomer for constructing azo-based π-conjugated polymers. Miyaura⁻Suzuki cross-coupling polymerization was conducted to develop copolymers containing an azobenzene unit as a photoisomerization block and a pyrimidine-based liquid crystal generator block. The prepared polymers exhibited thermotropic liquid crystallinity and underwent cis and trans photoisomerization upon irradiation with ultraviolet and visible light. Furthermore, the photoisomerization behavior was examined using optical absorption spectroscopy and synchrotron X-ray diffraction spectrometry.
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