For the (PA -) 1 (Na + ) 1 (Cl -) 1 (w) 0-5 clusters in Figure , we generally observe Na + to reside closer to the PA -monomer where it engages in linear or bifurcated salt bridges with the carboxylate moiety of PA -. Cl -is not observed to engage in hydrogen bonds with water or PA -in the lower hydrated (PA -) 1 (Na + ) 1 (Cl -) 1 and (PA -) 1 (Na + ) 1 (Cl -) 1 (w) 1 clusters due to Coulomb repulsions. However, as more water is added, it becomes increasingly involved in the nascent water hydrogen bonding networks of the higher hydrated clusters. Na + is, in this regard, becoming more encapsulated and solvated by the surrounding water, which we also observed for the (PA) 1 (Na + ) 1 (Cl -) 1 (w) 0-5 clusters as described above.