Fig. 5.

(A and B) Cartoons of the alkyl slab structure for (A) the IC model, comprising flexible ICs, and (B) the LL model, comprising a LL alkyl layer. Brown and blue circles, yellow flexible rods, and yellow areas represent, respectively, cation headgroups, anions, alkyl chains, and LL alkyl domains. (C–E) The density-based analysis. (C) The RTILs’ molecular volumes $V_m$ (symbols) as calculated from the RTILs’ mass densities ${\rho }_m$, and their linear fit (line). Note the excellent agreement for all $n$. (D) Calculated molecular areas $A_m$. (E) Calculated headgroup heights $d_h$. For discussion, see text.