“…In the case of weak PEs, such as PAA or PAH, small variations in pH cause modifications in the charge density (the ionization degree of the functional groups), leading to the modifications in the PEs conformation, in the thickness of the adsorbed polyelectrolytic films, in the swelling capacity of the multilayer, and its subsequent interactions with other compounds [ 47 ]. As reported by Guzman et al [ 48 ], the pH mainly influenced the deposition of weak PEs, such as PAA, which diffused better in the neighboring layers at low values of pH, leading to the adsorption of a thicker layer. At high values of pH, the diffusion of PAA into the opposite-charged layers is inhibited.…”