Photo-responsive covalent polymeric materials via azobenzene–molecular container host–guest interactions

Abstract

The photo-switchable trans–cis isomerization of azobenzene endows it with excellent photofunctional characteristics, including high quantum yield, minimal photobleaching and distinct conformational changes, making it a classic building block for fabricating advanced photo-responsive functional materials. The integration of azobenzene and molecular containers through reversible host–guest interactions has emerged as a powerful strategy for constructing photo-responsive systems, in which trans-azobenzene stably embeds into the cavity of molecular containers, while light-induced trans-to-cis isomerization triggers complex dissociation due to the bent conformation and enhanced hydrophilicity of cis-azobenzene, thus realizing precise light-mediated regulation of material properties. In this review, we systematically summarize the latest progress of photo-responsive polymeric materials based on azobenzene–molecular container host–guest interactions over the past three years, with an exclusive focus on covalent polymeric materials and covalent molecular containers. The reviewed content is innovatively categorized according to the polymerization components, namely “polymerization of azobenzene”, “polymerization of molecular container”, and “polymerization of both azobenzene and molecular container”, which clarifies the diverse design paradigms of such photofunctional materials. We detail the structural design, photo-responsive mechanisms and functional applications of the representative materials, and further discuss the key challenges and future development directions of this research field. This review is expected to provide a comprehensive summary of the current research status and offers novel perspectives for the rational design and fabrication of next-generation photofunctional polymeric materials based on azobenzene–molecular container host–guest interactions.