Before revision: The Langmuir equation states that for the adsorption of a molecule of adsorbate A onto a surface binding site S, a single binding site is used, and each free binding site is equally likely to accept a molecule of adsorbate: where: is the adsorbate is the surface binding site is the bound adsorbate/binding site pair The equilibrium constant for this reaction is then defined as: The equilibrium constant is related to the equilibrium surface coverage , which is given by: where: is the surface coverage (fraction, 0 is empty, 1 is fully covered) is the adsorption equilibrium constant Adsorption energy Because many polymers are composed of primarily of hydrocarbon chains with at most slightly polar functional groups, they tend to have low surface energies and thus adsorb rather poorly.
After revision: A + S <=> A - S'''The Langmuir equation states that for the adsorption of a molecule of adsorbate A onto a surface binding site S, a single binding site is used, and each free binding site is equally likely to accept a molecule of adsorbate: where: is the adsorbate is the surface binding site is the bound adsorbate/binding site pair The equilibrium constant for this reaction is then defined as: The equilibrium constant is related to the equilibrium surface coverage , which is given by: where: is the surface coverage (fraction, 0 is empty, 1 is fully covered) is the adsorption equilibrium constant Adsorption energy Because many polymers are composed of primarily of hydrocarbon chains with at most slightly polar functional groups, they tend to have low surface energies and thus adsorb rather poorly.