Variation of the isoelectric point as a function of the flow penetration degree, for various values of the nominal charge density ratio for layers 1 and 2 (panel A) and different values of (panel B). Model parameters, panel A: and Model parameters, panel B: the same as in A with and variable (C) Variation of the isoelectric point as a function of the electrolyte concentration and the ratio Model parameters, panel C: as in A with nm, In all these calculations, Eqs. 35–46 are used (particle composed of two concentric soft layers, Eq. 46).