Activators Regenerated by Electron Transfer for Atom‐Transfer Radical Polymerization of (Meth)acrylates and Related Block Copolymers

Abstract

Atom-transfer radical polymerization (ATRP) is a controlled or living radical polymerization (CRP) technique [1,2] that enables the preparation of new nanostructured materials that are not accessible by conventional free-radical polymerization (FRP). Reported herein is the ATRP of polar monomers such as (meth)acrylates and related block copolymers by means of a new initiating/catalytic method based on activators regenerated by electron transfer (ARGET) with ppm (10 À4 mol % vs. monomer) amounts of Cu catalyst.[3]ATRP [4][5][6][7] provides a simple route to many well-defined (co)polymers with precisely controlled functionalities, topologies, and compositions. [8][9][10] It has been very successfully applied to the preparation of many nanocomposites, hybrids, and bioconjugates. [11][12][13][14][15][16][17][18][19][20][21][22][23] The advantages of ATRP, in comparison with other CRP processes, include the large range of available monomers and (macro)initiators, the simplicity of reaction setup, and the ability to conduct the process over a large range of temperatures, solvents, and dispersed media. [6,7,24] ATRP (Scheme 1) is a repetitive atom-transfer process between a macromolecular alkyl halide P n ÀX and a redoxactive transition-metal complex Cu I ÀX/ligand in which P n C radicals propagate (rate constant of propagation k p ) and are reversibly formed (rate constants k a and k da ). The growing radicals also terminate by coupling or disproportionation (rate constant k t ).An inherent feature, but also a limitation of ATRP, is the presence of a catalyst (a transition-metal complex with Scheme 1. Mechanism for ATRP.

Evaluation of the confinement effect of nanoclay on the kinetics of styrene atom transfer radical polymerization

“…1 In this context, nitroxide-mediated polymerization, 2 reversible addition-fragmentation chain transfer polymerization (RAFT), 3 and atom transfer radical polymerization (ATRP) 4 have extensively been studied. Some advantages of ATRP over other CRP systems including the applicability to a wide variety of monomers and systems of polymerization, 5 the simplicity of the reaction setup and conditions (low temperature and pressure), and its less sensitivity to impurities 6 have made it an interesting field of study. ATRP can be employed not only to synthesize homopolymers but also to prepare various kinds of functional (chain end functionality or functionality on the backbone), gradient, graft, branched, star, and brush (co)polymer structures.…”

Controlled Cell Adhesion on PEG‐Based Switchable Surfaces

“…[14] Poly(OEGMA-co-MEO 2 MA) brushes were then grown from the surfaces using either standard-ATRP or AGET-ATRP methods. [15] All surface-modification strategies efficiently produced poly(OEGMA-co-MEO 2 MA) brushes on gold substrates. For example, the adsorption of polymer 2 ("grafting-onto" approach; strategy A) on gold could be monitored in real time by surface plasmon resonance (SPR; Figure 1 b).…”

Synthesis and Characterization of PDMS Based Triblock and Pentablock Copolymers

“…3.9. All signals of the 1 H-NMR spectra were assigned to their corresponding monomers and it can be declared that the synthesis of block copolymers have proceeded successfully [22][23][24][25]. The 1 H-NMR of block copolymers showed a signal at 0.0-0.2 ppm associated with CH 3 -Si methyl protons of PDMS along with the signals at 2.1-2.3 and 6.6-7.1 ppm corresponded to OCOCH 3 group from the PVAc segment and PSt segment respectively.…”