To explore the effect of the block ratio m : n on anion adsorption at different concentrations of NaNO 3 , we calculated time-averaged cumulative RDFs of NO - 3 and Cl -ions (see Figs. ). At the lowest salt concentration, c s = 0.1 M and for n ≤ 8, where the number of Cl -ions (< 40 ions) is comparable to the number of NO - 3 ions (30 ions), NO - 3 ions exhibit stronger adsorption to the polymers than Cl -ions. However, for n > 8, the number of Cl -ions exceeds that of NO - 3 ions, and the cumulative RDF of Cl -becomes larger, indicating a shift in adsorption preference. At higher salt concentrations (c s = 0.3 and 0.5 M), the number of NO - 3 ions is approximately equal to or greater than the number of Cl -ions, resulting in a greater fraction of NO - 3 ions adsorbed near the polymer chains as compared to Cl -ions.