Title: Photodeformable Azobenzene-Containing Polyimide with Flexible Linkers and Molecular Alignment

Author: Panpan Zhang, Zhongxu Lan, Jia Wei*, Yanlei Yu*

Journal: ACS Macro Lett., 2021, 10(4), 469-475

Abstract:

Azobenzene-containing polyimides (azo-PIs) as photodeformable materials have attracted scientific attention in view of combining photoresponse and high performance (such as excellent mechanical and thermal properties). In the previously reported photodeformation of azo-PIs, polarized blue–green light was utilized to produce concerted motion of azobenzene moieties based on the mechanism of photoinduced reorientation. Herein, we explored a designed azo-PI undergoing photodeformation upon unpolarized light irradiation. The azo-PI film aligned by the hot-stretching process exhibited fast and reversible bending behavior under alternate ultraviolet (UV) and visible (vis) light irradiation, indicating the efficient nano-to-macroscopic propagation of molecular deformation of azobenzene. Besides, the aligned azo-PI film even bent in hot water (80 °C) and hot silicone oil (100 and 120 °C) with UV light irradiation.

Fulltext Link: https://pubs.acs.org/doi/abs/10.1021/acsmacrolett.1c00040

In this paper, the azo-containing diamine monomer (DAC3AB) with flexible linkers is copolymerized with 4,4′-(hexafluoroisopropylidene)-diphthalic anhydride (6FDA) to prepare an azo-PI film that can be thermally stretched to align the liquid crystal orientation. The azo-PI film exhibited fast and reversible bending behavior under alternate ultraviolet (UV) and visible (vis) light irradiation, even bent in hot water (80 °C) and hot silicone oil (100 and 120 °C) with UV light irradiation.