Dialkyl Substituent Effects on the Interaction of Imidazolium Ionic Liquids with POPC Membranes by Molecular Dynamics

We employed molecular dynamics computer simulations to examine the effect of a second alkyl group in cations of imidazolium-based ionic liquids on the properties of a fully hydrated POPC membrane. Keeping a fixed hexadecyl group in the cations, a second methyl, butyl, and octyl group were considered. In any case, the cations inserted rapidly into the bilayer maintaing the membrane’s structure. Radial distribution functions indicate that an increased second alkyl chain in the cation favors configuration with deeper insertion. The presence of the cations preserves the hydration of the polar region of the bilayer without promoting water penetration into the lipophilic region.