Synthesis and properties of novel photoresponsive polyacetylene derivatives with an azobenzene mesogenic moiety in the side group

초록

We have synthesized novel mono-substituted acetylenes with a liquid crystalline azobenzene moiety in the side group such as 5-[4-(4'alkylphenylazo)phenoxy]-1-pentyne (alkyl group:H, pentyl, etc.) and then polymerized them with Ziegler-Natta(Fe(acac)(3)-AlEt3), metathesis(WCl6, MoCl5), and [Rh(NBD)Cl](2)-Et3N catalysts. Especially, the Rh complex catalyst containing benzene as a solvent produced a cis rich polymer with an extremely high yield of 97%. Spectroscopic characterizations of all polymers were also carried out in view of molecular weight, structure, and thermal history using GPC, FT-IR, H-1, C-13-NMR, UV-Visible, and DSC. Polyacetylene derivative having a pentylazobenzene group showed a smectic liquid crystalline phase with a fan-shaped texture through the polarizing optical microscope measurement. Also, photoresponsive characteristics of all monomers and polymers upon the irradiation of a UV monochromatic light have been investigated.

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