Ethylene Polymerization‐Induced Self‐Assembly (PISA) of Poly(ethylene oxide)‐block‐polyethylene Copolymers via RAFT

Abstract

Poly(ethylene oxide) (PEO) with dithiocarbamate chain ends (PEO–SC(=S)−N(CH3)Ph and PEO–SC(=S)−NPh2, named PEO‐1 and PEO‐2, respectively) were used as macromolecular chain‐transfer agents (macro‐CTAs) to mediate the reversible addition–fragmentation chain transfer (RAFT) polymerization of ethylene in dimethyl carbonate (DMC) under relatively mild conditions (80 °C, 80 bar). While only a slow consumption of PEO‐1 was observed, the rapid consumption of PEO‐2 led to a clean chain extension and the formation of a polyethylene (PE) segment. Upon polymerization, the resulting block copolymers PEO‐b‐PE self‐assembled into nanometric objects according to a polymerization‐induced self‐assembly (PISA).

Ethylene-Free Synthesis of Polyethylene Copolymers and Block Copolymers

“…15−18 Nevertheless, innovations in this regard, such as the copolymerization of ethylene with vinyl acetate by iodine transfer polymerization by the group of D'Agosto, are remarkable. 19,20 Advances in the synthesis of olefin block copolymers have also been achieved via a process called chain shuttling polymerization 21 or the synthesis of polyolefin-based block copolymers with styrenes or acrylates. 22 Furthermore, the functionalization of polyolefins in general, and PE in particular, is challenging due to a lack of functionalities or polar functional groups.…”

“…Based on this technique, PE can, for example, be synthesized by the homopolymerization of ethylene via reversible addition-fragmentation chain transfer (RAFT) polymerization or organometallic-mediated polymerization as demonstrated by Detrembleur et al Organometallic-mediated polymerization allows for the synthesis of PE block copolymers under high pressures from ethylene gas and suitable polar comonomers like vinyl acetate or carbonates, while recent developments additionally demonstrated the synthesis of degradable PE-based copolymers . Besides, the implementation of well-studied reversible-deactivation radical polymerization (RDRP) techniques for the synthesis of PE is established but still rely on ethylene gas as the monomer. − Nevertheless, innovations in this regard, such as the copolymerization of ethylene with vinyl acetate by iodine transfer polymerization by the group of D’Agosto, are remarkable. , Advances in the synthesis of olefin block copolymers have also been achieved via a process called chain shuttling polymerization or the synthesis of polyolefin-based block copolymers with styrenes or acrylates . Furthermore, the functionalization of polyolefins in general, and PE in particular, is challenging due to a lack of functionalities or polar functional groups …”

Synthesis of poly(methyl methacrylate)-b-polyethylene (PMMA-b-PE) block copolymers via conventional emulsion polymerization

“…Recently, ethylene-based copolymers were developed by our group through the use of reversible addition-fragmentation chain transfer (RAFT), [3][4][5] organotellurium mediated radical polymerization (TERP) 6 and iodine transfer polymerization (ITP) 7,8 under mild conditions (≤200 bar, ≤80 °C) in dimethylcarbonate (DMC), but also in dispersed media or via polymerization-induced self-assembly (PISA). 9,10 These techniques, however, require the use of controlling agents, which is not always compatible with the cost of the final structures that has to remain very low, particularly when considering ethylene-based products.…”

Polymers with multiple functions: α,ω-macromolecular photoinitiators/chain transfer agents used in aqueous photoinitiated polymerization-induced self-assembly

“…13–24 Over the past ten years or so, reversible addition–fragmentation chain transfer (RAFT)-mediated polymerization-induced self-assembly (PISA) has become one of the most commonly employed methods to prepare block copolymer nanoparticles with a diverse set of morphologies. 25–49 More importantly, the solids content of block copolymer nanoparticles prepared by RAFT-mediated PISA can be up to 50% w/w, which can overcome the disadvantage of the traditional solution self-assembly method (solids content <1% w/w). Typically, RAFT-mediated PISA is performed via thermal initiation at relatively high reaction temperatures ( e.g.…”