Adsorptive energy potentials, Gaussian distribution

A previous paper of this series (13) describes the analysis of adsorption iso- therms for heterogeneous surfaces in terms of a Gaussian distribution of adsorptive potentials. The distribution of adsorptive potential energies may not, however, have a form that is symmetrical about a mean it could possess enough asymmetry so that the adsorption isotherm could not be described by a model that assumed a Gaussian distribution. 

Figure 4.11. The uniqueness of the adsorption isotherm. If the distribution of adsorption site potential energies does not fit a Normal-Gaussian-type distribution function, as above in the figure, then the obtained experimental isotherm is not linearized by the Langmuir,...

The term weak adsorption implies that the entropic free energy of a chain is comparable to its electrostatic attraction energy to the interface. The chain is assumed to be Gaussian and its conformations are only weakly perturbed by interactions with the surface. This is the most severe approximation of the current model. We also assume that the polyelectrolyte-density profile is built up near the adsorbing surface without disturbing the electrostatic potential and ionic distribution near the interface prescribed by the Poisson-Boltzmann theory. A more general... 

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