The non-interacting polymer chain having N mer = 200 segments each b = 0.38 nm long is considered as an ideal reference of our simulation setup. The ideal radius of gyration equals to R id g = b √ N mer /6 = 2.19 nm. The solvation characteristics of ions cannot be captured directly in the implicit solvent model. Instead the value of the second virial coefficient B 2 for the monomer-ion interaction (without electrostatics) can be used as a global measure of the hydrated character and ion-specific affinity to the polymer. Strongly hydrated ions prefer to stay in the bulk solution thus there is a net repulsion between them and the uncharged polymer. That corresponds to a positive B 2 value of the monomerion interaction. On the other hand, weakly hydrated ions tend to preferentially adsorb to the polymer surface, which gives a net negative B 2 value of the monomer-ion interaction. The value of B 2 can be computed from the pairwise potential (eq 5). When the LJ potential is employed, ε 0.3 k B T gives a positive B 2 value (a net repulsion), while ε 0.3 k B T yields to a negative B 2 value (a net attraction).