Figure 3.

Effect of the ion valency on the predicted disjoining pressure acting between two similarly charged surfaces as a function of the separation distance between the two charged surfaces for z:1 and 1:z electrolytes (z = 1, 2, and 3) solutions using the BSK model (eq 21). To generate the various plots, we used the following parameter values: |q_s| = 0.1 C/m², c₀ = 0.1 M, and ϵ_r = 80. (a) Predicted disjoining pressure of a z:1 electrolyte solution, corresponding to a negative charge on the two surfaces, q_s = −0.1 C/m². (b) Predicted disjoining pressure of a 1:z electrolyte solution, corresponding to a positive surface charge on the two surfaces, q_s = +0.1 C/m².