P. Nikitas, A MOLECULAR-MODEL FOR POLYLAYER FORMATION ON ELECTRODE SURFACES, Journal of electroanalytical chemistry [1992], 451(1-2), 1998, pp. 249-259
The statistical mechanical approach in studying multilayer adsorption
phenomena presented in the J. Phys. Chem., 100 (1996) 15247, is extend
ed to electrified interfaces. According to this approach, an adsorbed
him composed of solvent and adsorbate molecules forming n layers is ma
thematically equivalent to a monolayer of n + 1 components; which are
the solvent molecules and columns of i (=1, 2,..., n) adsorbate molecu
les. The contribution of the field-dipole interactions to the chemical
potentials is calculated by assuming that the electric field is not u
niform across the adsorbed layer and all the other contributions, comi
ng from the distribution of the adsorbed particles over the adsorption
sites and from the particle-particle and particle-adsorbent interacti
ons, are calculated using lattice statistics. It is shown that the mod
el developed can predict, at least qualitatively, the adsorption chara
cteristics of n-heptanol, n-hexanol, n-heptanoic acid and n-hexanoic a
cid on Hg when they form polylayers, the peculiar behaviour characteri
sed by the appearance of just one transition potential at certain adso
rption systems, like the adsorption of methyl- and dimethylpyridines o
n Hg, and finally the appearance of a transition pit inside another pi
t at the capacitance plots, observed in several experimental systems w
ith ionic molecules or molecules of biological importance. (C) 1998 El
sevier Science S.A. All rights reserved.