Simple Full-Spectrum Heterogeneous Photocatalyst for Photo-induced Atom Transfer Radical Polymerization (ATRP) under UV/vis/NIR and its Application for the Preparation of Dual Mode Curing Injectable Photoluminescence Hydrogel

Abstract

The utilizing light with broadband range has attracted lots of research interest for the photo induced reversibledeactivation radical polymerization (RDRP). However, it is still a challenge for a single catalyst to simultaneously respond to various lights with highly varied wavelengths. Here, we proposed a simple strategy for the preparation of a heterogeneous photocatalyst suitable for photo induced atom transfer radical polymerization (photoATRP) under full spectrum (from UV/vis light to NIR), by combining pyridine nitrogen doped carbon dots (N-CDs) and upconversion nanoparticles (UCNPs). In the presence of these robust UCNP@SiO 2 @N-CDs composite particles, the photoATRP could be carried on under the different irradiations of UV, blue, green, red, white, and 980 nm NIR light, with a low loading of part per million concentrations of the CuBr 2 /L catalyst. Moreover, the excellent solvent and aqueous compatibility allow UCNP@SiO 2 @N-CDs to be capable for photoATRP in both organic solvents and aqueous media, providing well-defined hydrophobic and hydrophilic polymers with low dispersity and excellent chain-end fidelity. In addition, the photoATRP with 980 nm NIR exhibited excellent penetrations through visible-light-proof barriers. The system could be used for the preparation of an injectable hydrogel that had dual curing and photoluminescence modes. Owing to the "living" characteristics of polymer chains achieved through ATRP, the hydrogel was capable to be easily repaired by using monomer as the binder.

An aqueous photo-controlled polymerization under NIR wavelengths: synthesis of polymeric nanoparticles through thick barriers

“…Photoinduced reversible deactivation radical polymerization (photo-RDRP) 1–58 techniques enable the production of polymers with low dispersity and defined architectures and provide a high degree of spatio–temporal reaction control. As a useful photo-RDRP variant, photoinduced reversible addition–fragmentation chain transfer polymerization (photo-RAFT) polymerization process 26–58 often uses ppm range photocatalysts (PCs) to activate RAFT agents under visible light without the need for deoxygenation.…”

“…[61][62][63] Meanwhile, using aqueous media instead of organic solvents for polymerizations provides economic and environmental benets, further increasing these systems for bio-applications. 50,[61][62][63][64] However, long-wavelength-mediated aqueous photo-RDRP systems have seldom been reported, 17,20,51 due to the typically low solubility of NIR absorbing catalysts in aqueous media. In 2020, Qiao and co-workers developed an aqueous visible-and NIR-mediated photoinduced electron/energy transfer reversible addition-fragmentation chain transfer (PET-RAFT) polymerization process catalyzed by a selfassembled carboxylated porphyrin photocatalyst.…”

“…Recently, the groups of Pan and Pang reported the successful utilization of upconversion nanoparticles as heterogeneous photocatalysts to induce photoinduced atom-transfer radical polymerizations (photo-ATRP) under NIR laser light in aqueous media. 17,20 Nevertheless, prior deoxygenation and high-intensity light sources were required in these systems to achieve appreciable monomer conversions.…”

Atom Transfer Radical Polymerization: A Mechanistic Perspective

“…Pyridine nitrogen doped-CQDs enabled ultrafast, oxygen tolerant photo ATRP in water, which was exploited for 3D printing . Moreover, nitrogen doped-CQDs could work under NIR light by combining them with UCNPs in composite particles . Polymethine derivatives with a zwitterionic nature could be used to mediate a dual-catalyzed ATRP under NIR light …”

A Porphyrin‐Based Organic Network Comprising Sustainable Carbon Dots for Photopolymerization

“…Recently, CD s were also employed as photoreduction reagents in a Cu 2+ based system resulting in activation of a photo‐ATRP [35] . Here, excitation of up‐conversion nanoparticles resulted in excitation of CD s whose excited state resulted in formation of the respective hole CD + ⋅.…”