(a) Stabilities of dimers and trimers in TIP3P, GBSW/SA, GBSW/VGSA solvents. Notations: f: Phe, 1: Leu, p: parallel, pd: parallel displaced, etf: edge-to-face, p12/p13: pairs from trimers. (b) PMFs of Leu trimer in different solvents. The green traces were constructed by summing two pair-wise PMFs (p12 and p13). The inserts plot the nonpolar contributions. Note that SA leads to anti-cooperativity at contact minimum (~5 Å) instead of cooperativity as in TIP3P and GBSW/VGSA.