For pH ≪ pK a,acid , the microgel is thus uncharged, while for pH ≫ pK a,acid it acquires a maximum charge of q max,a = -N a e with the elementary charge e. In interacting systems, the (electrostatic) interactions lead to deviations from the ideal ionization behavior, such as the suppressed ionization behavior observed in weak polyacids. Theoretically accounting for the interactions encoded in the excess chemical potentials is challenging and requires approximate analytical approaches or computer simulations.