Reconfigurable and Recyclable Photoactuators Based on Azobenzene-Containing Polymers

Abstract

Photoactuators are promising smart materials that can adapt their shapes upon light illumination. Smart materials with recycling, reusable, and reconfigurable properties are crucial for a sustainable society, and it is important to expand their function. Recently, much effort was made to address the issue of reprocessability and recyclability of photoactuators. Based on the development of polymer chemistry, supramolecular chemistry, and dynamic covalent chemistry, it is now possible to prepare reconfigurable and recyclable photoactuators using azobenzene-containing polymers (azopolymers). Herein, the recent advances on reconfigurable and reprocessable photoactuators, including dynamic crosslinked networks systems and non-covalently crosslinked azobenzene-containing polymers, were reviewed. We discuss the challenges in the field as well as the directions for the development of such photoactuators.

Effect of Surface Properties on the Photo-Induced Crawling Motion of Azobenzene Crystals on Glass Surfaces

“…of azobenzene-containing materials. One of the most successful molecular systems in azobenzene-containing materials is photoactuators, especially in liquid crystal elastomers ( Zhu et al, 2020 ; Chen et al, 2020 ). These polymers show contraction/expansion, bending, twisting, and oscillation by light and are expected to be used as 4D printing materials.…”

Reprocessable Photodeformable Azobenzene Polymers

“…Moreover, the fully recyclable photodeformable azo polymers with reversible DCB-crosslinked networks that can be reprocessed at room temperature also hold much promise. In particular, some breakthroughs have been achieved in preparing reprocessable photodeformable azo polymers with ultralarge contraction [ 58 ], strong photoinduced stress (up to 7 MPa) [ 66 ], and various complex 3D motions [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ].…”

“…Photodeformable azobenzene (azo) polymers are a class of smart functional polymers that can convert light energy into macroscopic displacement or deformation (i.e., photomechanical effects) [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. As a photoswitchable chromophore, azo unit can reversibly change the conformation between two structural configurations (i.e., trans and cis isomers) with high quantum efficiency and fatigue resistance [ 16 , 17 ].…”

“…So far, a great number of photodeformable azo polymers with various chemical structures have been developed via different synthetic strategies [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. They are typically prepared by first orientating the azo mesogens (or together with other mesogens) through mechanical stretching or surface alignment and the subsequent locking of the ordered structures through various crosslinking reactions.…”

Chemically modified nucleic acids and DNA intercalators as tools for nanoparticle assembly

“…[135][136][137] One of the most interesting characteristics of azo compounds is the quickly induced and reversible trans-cis photoisomerisation of the azo bond as well as the structural changes occurring when they are integrated within other materials. 138,139 This interconversion is induced by light (at specific wavelengths), which renders azo compounds excellent candidates for photo-switching activity effectively controlling the optical, chemical, mechanical and electronic properties of materials. 138 Fig.…”