Red-Light-Driven Atom Transfer Radical Polymerization for High-Throughput Polymer Synthesis in Open Air

Abstract

Photoinduced reversible-deactivation radical polymerization (photo-RDRP) techniques offer exceptional control over polymerization, providing access to well-defined polymers and hybrid materials with complex architectures. However, most photo-RDRP methods rely on UV/visible light or photoredox catalysts (PCs), which require complex multistep synthesis. Herein, we present the first example of fully oxygen-tolerant red/ NIR-light-mediated photoinduced atom transfer radical polymerization (photo-ATRP) in a high-throughput manner under biologically relevant conditions. The method uses commercially available methylene blue (MB + ) as the PC and [X−Cu II /TPMA] + (TPMA = tris(2-pyridylmethyl)amine) complex as the deactivator. The mechanistic study revealed that MB + undergoes a reductive quenching cycle in the presence of the TPMA ligand used in excess. The formed semireduced MB (MB • ) sustains polymerization by regenerating the [Cu I /TPMA] + activator and together with [X−Cu II /TPMA] + provides control over the polymerization. This dual catalytic system exhibited excellent oxygen tolerance, enabling polymerizations with high monomer conversions (>90%) in less than 60 min at low volumes (50−250 μL) and high-throughput synthesis of a library of well-defined polymers and DNA−polymer bioconjugates with narrow molecular weight distributions (Đ < 1.30) in an open-air 96-well plate. In addition, the broad absorption spectrum of MB + allowed ATRP to be triggered under UV to NIR irradiation (395−730 nm). This opens avenues for the integration of orthogonal photoinduced reactions. Finally, the MB + /Cu catalysis showed good biocompatibility during polymerization in the presence of cells, which expands the potential applications of this method.

Iron–Gold Galvanic-Assisted Rapid Grafting of Polymer Brushes on n-Silicon for a Triboelectric Nanogenerator

“…Grafting polymer brushes with targeted construction and functionality have been intensively used to realize surface modifications and possessed potentials in biolubrication, − antifouling, , biomedical, and energy engineering. − An appealing strategy for preparing diverse polymer brushes is surface-initiated atom transfer radical polymerization (SI-ATRP or SI-CRP), , including activators regenerated by electron transfer (ARGET) ATRP, photo-ATRP, , electrochemically mediated ATRP (eATRP), − and supplemental activator and reducing agent (SARA) ATRP. − The last mentioned technology deserves special attention because it allows precise control of the chemical composition, structure, and thickness of polymer brushes. − So far, the transition metal catalysts have been extended to Cu, ,,− Fe, ,, Zn, − and Sn since surface-initiated zerovalent metal-mediated controlled radical polymerization (SI-Mt 0 CRP) was proposed. Among them, SI-Fe 0 ATRP was considered one of the best choices for “green” reactions because of the low toxicity, cost-effectiveness, and biocompatibility of iron-based catalysts. , However, the classical iron-based catalytic systems normally show limited monomer suitability, slow polymerization rate, and weak controllability over the polymerization. , …”

Electrochemically Mediated Surface-Initiated Atom Transfer Radical Polymerization by ppm of CuII/Tris(2-pyridylmethyl)amine

“…As one of the typical soft interfacial materials, polymer brushes provide an efficient and convenient means to modify the physicochemical characteristics of material surfaces; this is facilitated by a deep mechanistic understanding and versatile synthetic strategies. − Polymer brushes have found applications in a broad spectrum of fields, including the tuning of physical and chemical properties, , such as antifouling and − lubrication. − Reversible-deactivation radical polymerizations (RDRPs) enable the preparation of polymers with low dispersity, well-controlled architecture, and molecular weight. − Among RDRPs, atom transfer radical polymerization (ATRP) is of particular interest. The recently developed external stimuli-mediated ATRP has attracted great attention due to its ability to overcome the shortcomings of traditional surface-induced polymerizations, including rigorous synthetic protocols, low efficiency of monomer utilization, and harsh reaction conditions. − Electrochemically mediated ATRP (eATRP) is such an example that utilizes electrical stimulus to modulate the polymerization process. − This method provides easy control and manipulation of polymer growth in aqueous solutions and allows the synthesis of (co)­polymers with complex architectures and functionalities.…”

Impact of Interfacial Halogen Bonding with a Surfactant on Miniemulsion Reversible Chain Transfer-Catalyzed Polymerization

“…In RDRPs, the key control mechanism is the reversible deactivation of radical species; that is, active radicals generated from initiators can be quickly deactivated to dormant species and the dormant species can be activated to radical species again. Various RDRP mechanisms have been developed, including nitroxide-mediated polymerization (NMP), − atom transfer radical polymerization (ATRP), − reversible addition–fragmentation chain transfer (RAFT) polymerization, − organotellurium-mediated living radical polymerization (TERP), , and single-electron transfer living radical polymerization (SET-LRP). , …”