Adsorption on Interparticle Forces

J. E. Lane, T. H. Spurling. Monte Carlo simulation of the effects of adsorption on interparticle forces. Aust J Chem 55 231-239, 1980. 

Figure 5.6 Effect of adsorption on interparticle forces, (a) At large separations the adsorption at the two surfaces is independent of separation adsorption does not contribute to the interparticle force, (b) At closer separations the adsorption fields of the two surfaces overlap and enhance the adsorption in the space between the surfaces 3Tf /3H is negative so addition of component 2 leads to an attraction [9(H) negative/. (c) At very close approach the space available for adsorption decreases 3r /j/3H is positive and adsorption effects make a repulsive contribution to the interparticle force.

It is interesting to note that, if the formation of a double layer is regarded as the adsorption of counter-ions by the charged particle, then the principles concerning the effect of adsorption on interparticle forces set out in Chapter 5 ean be applied. Thus, as two double layers overlap at constant potential, counter-ions are rejected from the space between the particles, the adsorption of counter-ions decreases, and, according to the general principles discussed in Chapter 5, the particles repel one another. 

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