[ACS APM] Photoresponsive Azobenzene Materials Based on Pyridine-Functionalized Benzoxazines as Surface Relief Gratings
writer：Ahmed F. M. EL-Mahdy, Fang-Wen Lin, Wei-Hung Su, Tao Chen,* and Shiao-Wei Kuo*
keywords：Azobenzene, Pyridine, Benzoxazine, Trans-to-Cis, Surface relief gratings
source：期刊
specific source：ACS Appl. Polym. Mater., 2020, 2, 2, 791-804
Issue time：2020年
We describe the one-pot syntheses of an azobenzene- and pyridine-functionalized benzoxazine
monomer (PAPBZ) and a main chain–type polybenzoxazine (BAPBZ) through Mannich
condensations of a diamino- and azobenzene-containing pyridine derivative (Azo-Pyridine-2NH2), paraformaldehyde, and either phenol or bisphenol in a mixture of toluene and EtOH. Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy confirmed the chemical structures of the benzoxazine monomer and polymer. The thermal curing behavior and stability of these benzoxazines were monitored using differential scanning calorimetry, FTIR spectroscopy, and thermogravimetric analysis; the PAPBZ monomer underwent complete ring opening polymerization to form its polybenzoxazine, while the BAPBZ polymer also underwent thermal curing to give a high-density cross-linked polybenzoxazine. Because of the photoresponsive azobenzene units in the benzoxazine monomer and in the main chain of the polybenzoxazine, these materials exhibited photoresponsivity through reversible photoinduced trans-to-cis isomerization under UV irradiation. The degrees of isomerization of PAPBZ and BAPBZ were 19.3 and 13.9%, respectively. In addition, we used these materials to fabricate surface relief gratings exhibiting interference patterns with tunable long-range order. Accordingly, such azobenzene- and pyridine-functionalized benzoxazines appear to have applicability within optical devices and optical storage media.