Synthesis of 1-Vinyl-3-ethylimidazolium-Based Ionic Liquid (Co)polymers by Cobalt-Mediated Radical Polymerization

Abstract

The cobalt-mediated radical polymerization (CMRP) of 1-vinyl-3-ethylimidazolium bromide (VEtImBr) is described. Polymerizations were performed at 30 °C in solution either in dimethylformamide (DMF) or in methanol (MeOH) or in a mixture of both solvents, using a preformed alkyl–cobalt(III) adduct, CH3OC(CH3)2CH2–C(CH3)(CN)–(CH2–CHOAc)<4–Co(acac)2, as the mediating agent. Excellent control over molecular weights and dispersities (M w/M n ∼ 1.05–1.06) was achieved in MeOH, with a linear increase of experimental molecular weights with the monomer conversion. Substituting methanol for DMF induced much faster polymerization process, even under quite high diluted conditions: for instance, about 80% monomer conversion was reached in 30 min in DMF, compared to 10 h in MeOH. However, size exclusion chromatography (SEC) traces of PVEtImBr samples synthesized in DMF revealed a side population in the high molecular weight region, presumably due to the occurrence of irreversible coupling reactions of a small proportion of growing chains. Well-defined diblock copolymers featuring both a poly(vinyl acetate) (PVAc) block and a PVEtImBr-based poly(ionic liquid) block, PVAc-b-PVEtImBr, were next obtained by sequential CMRP of VAc and VEtImBr. To this end, a PVAc-Co(acac)2 was first prepared by CMRP and employed as a macroinitiator for the polymerization of VEtImBr either in methanol or in a mixture of DMF and MeOH (2/1: v/v) at 30 °C. Finally, cobalt-mediated radical coupling (CMRC) of the aforementioned PVAc-b-PVEtImBr diblock copolymers, using isoprene as a simple coupling agent, led to unprecedented and structurally well-defined PVAc-b-PVEtImBr-b-PVAc triblock copolymers.

Precision Synthesis of Poly(Ionic Liquid)‐Based Block Copolymers by Cobalt‐Mediated Radical Polymerization and Preliminary Study of Their Self‐Assembling Properties

“…Route A. Synthesis of PVAc‐ b ‐PVEtImBr and PVAc‐ b ‐PVEtImBr‐ b ‐PVAc by sequential CMRP using alkyl‐cobalt(III) adduct 1 as a mediating agent as previously reported . Route B. Synthesis of PVAc‐ b ‐PVBuImBr by sequential CMRP using Co(acac) 2 2 and V‐70 3 .…”

“…We have recently introduced a new family of PIL BCPs based on poly( N ‐vinyl‐3‐ethylimidazolium bromide) (PVEtImBr) and poly(vinyl acetate) (PVAc) . Synthesis of these compounds was achieved by sequential cobalt‐mediated radical polymerization (CMRP) in solution .…”

Polymerized ionic liquid block copolymers for electrochemical energy

“…Table 1 lists various controlled polymerization techniques (e.g., NMP, RAFT, anionic, CMRP, ROMP, ATRP) that have recently been explored to prepare PIL block copolymers. 13,[15][16][17][18][19][20][21][22][23][24][25][26]28,29,[35][36][37][38][39][40][41][44][45][46][47] The former allows for facile molecular weight determination of the non-ionic precursor block copolymer with conventional techniques, such as gel permeation chromatography (GPC). 13,[15][16][17][18][19][20][21][22][23][24][25][26]28,29,[35][36][37][38][39][40][41]…”

Controlled Synthesis of Ethylene-Vinyl Acetate Based Copolymers by Organometallic Mediated Radical Polymerization

“…In this case, the equilibrium between dormant and actives species can be adjusted by changing the metal center (23)(24)(25) and/or ligands (26)(27)(28). For example, bis(acetylacetonato)cobalt(II) (Co(acac) 2 ) offers an unequalled control of the radical polymerization of N-vinyl amides (29), N-vinylimidazolium (30,31) and vinyl acetate (32)(33)(34). For example, bis(acetylacetonato)cobalt(II) (Co(acac) 2 ) offers an unequalled control of the radical polymerization of N-vinyl amides (29), N-vinylimidazolium (30,31) and vinyl acetate (32)(33)(34).…”