Bis(trifluoromethylsulfonyl)amide based "polymeric ionic liquids": Synthesis, purification and peculiarities of structure-properties relationships

A series of bis(trifluoromethylsulfonyl)amide based "polymeric ionic liquids" (PILs) as high molecular mass analogues of the corresponding imidazolium, ammonium and pyrrolidinium ionic liquids (ILs) was synthesized with high purity and fully characterized including electrochemical properties. The PILs differed by the nature of the cation, the quantity of the ionic centers in each monomer repeating unit, and the alkyl length of the spacer. Two novel ionic liquid like monomers (ILMs), namely 1,3-bis(N,N,N-trimethylammonium)-2-propylmethacrylate bis(trifluoromethylsulfonyl) amide (ILM-2) and N-[(2-methacryloyloxy)-ethyl]-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (ILM-4) were synthesized and characterized. Optimal conditions for the free-radical polymerization of the ILMs were identified for the first time. It was demonstrated that, among the tested organic solvents, 1-methyl-3-ethylimidazolium bis(trifluoromethylsulfonyl)amide IL was the best reaction medium in terms of the achievement of high polymer yields and molecular masses. For the first time, the influence of the residual monomer presence inside the PIL film on the resultant conductivity was clearly shown. The impact of the molecular mass of the PILs on the ionic conductivity was firstly studied as well. Finally, the copolymerization of ILMs with poly(ethylene glycol)dimethacrylate (PEGDM) was carried out yielding tight elastic films with the highest conductivity equal to 3.2 x 10(-6) S/cm at 25 degrees C. (C) 2011 Elsevier Ltd. All rights