Deposition at Random Site Surfaces

The above theoretical data obtained for quasi-continuous surfaces can be used as reference states for the interpretation of particle deposition at random site surfaces, as discussed below. 

The random site surface (RSS) regime is pertinent to nanoparticle (colloids, proteins, polyelectrolytes) deposition at surfaces bearing isolated centers such as ions, smaller particles or macromolecules able to bind the solute particles irreversibly. 

The most important parameters characterizing the RSS process are the initial deposition probability governing the kinetics, expressed usually in terms of the site coverage 0s, and the jamming coverage of particles. For disk shaped sites, one can easily deduce that the initial deposition probability of particles (in the limit when their coverage remains very low) equals [49]  

As can be noticed, in this case, Po increases proportionally to the particle-to-site size ratio 2,, exceeding significantly the adsorption probability on disk shaped sites, characterized by the same coverage. 

However, for higher coverage of spherical sites, p increases at a smaller rate with their coverage as Equation 11.4 predicts, because the effective interaction areas start to overlap. Therefore, for higher coverage 0s, p can be well approximated by the 

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