Panel a of Fig. shows the synergistic effect between DS -, water, and C 12 E 6 (Eq. 25 with U =DS -). The change in the total interfacial free energy (relative to the bulk) is negative as a result of introducing the C 12 E 6 monolayer into the AWI, ∆ C F (2) DS -,W ⊕C (z), hence there is (attractive) synergy between DS -and C 12 E 6 . The energetic component of the synergistic effect includes the interaction of DS -with C 12 E 6 , as well as the change in the DS -interaction with water at the ACWI compared to the AWI, and is attractive, mostly due to the (LJ) stabilization of DS -within the C 12 E 6 monolayer, as discussed above.