From the figure, we see that the slow monotonous increase of π g for Gaussian model (continuous blue line) with growing swelling ratio leads to a pronounce increase of the equilibrium size as we rise the microgel bare charge. On the other hand, π g in the Langevin model (dashed red line) diverges for the swelling ratio corresponding to the maximum extension of the chains, indicated in the figure with a vertical dashed gray line, which causes a saturation of the equilibrium size as we increase microgel bare charge. In Fig. , we plot the equilibrium swelling ratio relative to the dry radius (linear deformation factor) versus bare charge Z for both elastic models. We see that the Gaussian model presents a steeper grow than the Langevin case when increasing Z. With further increase in Z, the chains reach their maximum extension and Langevin equilibrium size saturates, while Gaussian equilibrium size remains growing largely overcoming Langevin one. In order to test both models, we compare their swelling predictions versus coarse-grained microgel simulations. One important point to take into account when comparing against simulations and experiments is the choice of the reference microgel volume. The description of swelling is formulated in terms of the (collapsed) dry microgel volume, which is, however, very difficult to access experimentally nor in coarsegrained simulations. After extensive drying, a real gel network might still contain a significant amount of solvent, while it is impossible to define a dry state in simulations with implicit solvent and soft interactions. Therefore, when contrasting versus simulations, we are going to use the reference collapsed volume as a fitting parameter in the theoretical models.