Photo‐responsive block copolymer containing azobenzene group: Synthesis by reversible addition‐fragmentation chain transfer polymerization and characterization

Abstract

The design and synthesis of a new azobenzene‐based methacrylate monomer (Azo‐IEM) was demonstrated, and its polymerization behavior during reversible addition‐fragmentation chain transfer (RAFT) polymerization was investigated. Well‐defined homopolymer and amphiphilic block copolymer containing Azo‐IEM monomeric units were successfully prepared as evidenced by NMR and GPC analysis. Moreover, the photo‐triggered reversible isomerization of polymer products in selected solvents was investigated. Finally, TEM analysis showed that there were significant differences in the nanoparticle morphologies when the block copolymer samples were irradiated with different wavelengths of light (i.e., UV and visible). The size and shapes of the p(HEMA‐b‐Azo‐IEM) polymer capable of transitions upon changes in Vis/UV light exposure which prepared from MeOH/CHCl3 mixture solvent. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47870.

Design of photoswitchable adhesives based on azobenzene derivatives

“…In addition, TEM analysis showed that the morphology of the nanoparticles of the block copolymer samples was significantly different under different light wavelengths. [28] Azobenzene polymers have high spatial and temporal resolution, photoinduced healing and processing properties due to the photoisomerization of some azobenzene polymers that can lead to solid-liquid reversible transformation shown in Figure 2d. The researchers investigated the synthesis and photoresponse of azobenzene polymers with different spacer lengths between the polymer backbone and side-chain azobenzene monomers.…”

Dual-responsive polymers synthesized via RAFT polymerization for controlled demulsification and desorption

“…Given the unique properties of dual-responsive polymers, we attempt to design and synthesize a type of polymer in simultaneous response to the pH and light stimulations and explore their performance in broader applications related to reversible emulsi cation and adsorption. Light-sensitive polymers can change the hydrophobic-hydrophilic balance by photoreaction upon irradiating with light, which generally incorporates photochromic groups (i.e., azobenzenes, o-nitrobenzyl esters) into the side chains 1,22,23 . In particular, these polymers with azobenzene structures can guarantee the reversible cis-trans isomerization with respect to light irradication 24,25 .…”

Photocontrolled Azo-Containing Adhesives

“…The function of light control is often achieved by introducing light responsive groups into the system by methods like incorporation, [9] addition, [10] modification, [11] etc. Azobenzene derivatives are often used to achieve the purpose of photocontrolled debonding and reuse, whose physical and chemical properties are changed significantly by their photoisomerization under irradiation.…”