Surface-Initiated Zerovalent Metal-Mediated Controlled Radical Polymerization (SI-Mt⁰CRP) for Brush Engineering

Abstract

This work for the f irst time directly utilized a Sn(0) sheet as the only catalytic source for surface-initiated controlled radical polymerization (SI-Sn 0 CRP) to fabricate biocompatible polymer brushes under ambient conditions.

Grafting of Poly(ionic liquid) Brushes through Fe0-Mediated Surface-Initiated Atom Transfer Radical Polymerization for Marine Antifouling

“…Meanwhile, the LEIS analysis was also performed (Figures 2c and S2), and the impedance showed the inverse proportion against the ligand concentration, which indicates an enhanced dissociation of Fe species (Figure 2d). However, when the ligand concentration was further increased to 100 mmol, the obvious thickness decreased (90 ± 4.8 nm), probably due to the fact that more Fe III deactivator being generated by disproportionation moderated the process of Fe 0 SI-ATRP 25,27 (Figure 2e).…”

“…26 We then introduced a glass spacer with a height of 1 mm at one side of the clamped plates, which allowed a gradual variation of the distance between the Fe source and the initiating surface. The diffusion time for activator species (Fe 0 or/and Fe II species) 25,27 gradually varied along the surface, resulting in the changes of polymerization rate and leading to polymer brush gradients (Figure 3a). After 4 h of polymerization, the PIL-Br brush thickness progressively varied from 62.6 nm (left, Figure 3b) to 84.8 nm (middle, Figure 3c) and 148.6 nm (right, Figure 3d) across a 2 cm long substrate.…”

“…After 1 h of polymerization, the thickest polymer brush was found when tris­(2-dimethylaminoethyl)­amine (Me 6 TREN, 80 mmol) was employed, reaching 98 ± 1.8 nm (Figure a). It was known that the polymerization rate of Fe 0 SI-ATRP was critically dependent on the corrosion of metallic iron in the presence of the ligand. , Therefore, we investigated the corrosion behaviors of the Fe(0) sheet in the reaction media with different kinds of ligands by local electrochemical impedance spectroscopy (LEIS). It was obvious that the impedance in the presence of Me 6 TREN (about 1.45 × 10 6 Ω) was lesser than those of other ligands (Figure S1), which indicated the fastest corrosion of the Fe(0) plate and led to the highest growth rate of the polymer brush.…”

“…Surface-initiated atom transfer radical polymerization (SI-ATRP), a typical kind of “grafting-from” method, is particularly effective in functionalizing a variety of substrates with antibacterial polymer brushes by regulating the type of monomers and polymerization components. − Among them, Fe(0)-mediated surface-initiated atom transfer radical polymerization (Fe 0 SI-ATRP) has recently emerged as an appealing method for surface modification with cytocompatible polymer brushes under ambient conditions in an organic or aqueous medium. − In the Fe 0 SI-ATRP system, iron species (Fe II /L and Fe III /L) are generated by consuming dissolved oxygen from an iron plate (Fe 0 ) in the presence of the ligand, then undergo disproportionation/comproportionation with Fe 0 , and diffuse to the initiating surface to trigger the surface-initiated polymerization. Through Fe 0 SI-ATRP, diverse functional polymer brushes could be easily accessible for targeted applications. , …”

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.…”