Title: Photoinduced Deformation of Amorphous Polyimide Enabled by An Improved Azobenzene Isomerization Efficiency

Author: Xuejie Sun, Jia Wei*, Yanlei Yu*

Journal: Polym. Chem., 2022, 13, 5447-5452 (Front Cover)

Abstract:

Photodeformable azobenzene-containing polyimides (azo-PIs) have attracted attention due to their photo-response, good mechanical properties, and thermal stability. The deformation principle of azo-PIs mainly depends on the accumulation of conformational changes in one direction by polarized-light irradiation or pre-stretching. Herein, we synthesize a new deformable azo-PI and put forward a different strategy to achieve photodeformation by improving the azobenzene isomerization efficiency, which is attributed to the incorporation of azobenzene into the side chains of the polyimide (s-azo-PI). The s-azo-PI film exhibits reversible bending behaviour under alternate ultraviolet and visible light irradiation without using polarized light or pre-stretching. By means of this photodeformable behaviour, origami- or kirigami-inspired deformable 3D-structure objects, such as a cubic box and roller, are easily manufactured without any prior treatment, showing the potential to broaden the application of azopolymers in smart 3D actuators.

Fulltext Link: https://pubs.rsc.org/en/content/articlelanding/2022/py/d2py00691j

In this work, a new strategy to improve the isomerization efficiency of polyimide by introducing azobenzene into the side chain of polyimide was proposed. The polyimide films prepared by this method can exhibit reversible bending behavior under alternate UV and visible light irradiation without any pretreatment (such as orientation) after thermal imidization. This photo induced deformation behavior simplifies the processing of deformable 3D structure actuators, and broadens the potential application of azobenzene polymers in the field of intelligent 3D actuators.