Tuning conformational structures of imidazolium ionenes with 1-ethyl-3-methylimidazolium ionic liquid solvents

The structures and conformations of imidazolium ionenes solvated in 1-ethyl-3-methylimidazolium ionic liquids (ILs) ([C(2)mim'][X-]) are investigated using molecular dynamics simulations. Four different ionenes poly(decylimidazolium) (PD10), poly(tetraethyleneglycolimidazolium) (PE10), alternating copolymer (P(ED)5), and a block copolymer PE5D5 are immersed in [C(2)mim'][X-], where [X-] = thiocyanate [SCN-], tetrafluoroborate [BF4-], and trifluoromethanesulfonate [TfO-]. The radius of gyration indicates that the ionene chains are more extended when immersed in [TfO-] compared to [BF4-] and [SCN-], while the sol-vent accessible surface area shows that PE10 is the most contracted ionene among all systems. The electrostatic interactions between the ionenes and the ILs are very consistent with the inherent electrostatic characteristics of the different anions, which can be quantified using the Ionic Polarity Index (IPI). The ionene configurations and dynamics strongly depend on the backbone functionality and architecture of the chain, due to the balance between the inter-and intra-molecular interactions in these systems.(C) 2022 Elsevier Ltd. All rights reserved.

Automated summary

The structures and conformations of imidazolium ionene polymers solvated in 1-ethyl-3-methylimidazolium ionic liquids were investigated using molecular dynamics simulations. The study revealed that the choice of anion in the ionic liquid affects the extension of the ionene chains, and the configuration and dynamics of the ionenes depend on the functionality and architecture of the chain.