Adsorption Isotherms for Polymer Chains Adsorbed from Θ Solvents

Abstract

In the case of interacting polymer chains near the interface, the first layer at the interface, corresponding to the thickness of segments, is treated as a polymer solution to which the Flory—Huggins theory is applied. Interaction in other layers is assumed to be absent for Θ solvents. On minimizing the free energy, adsorption isotherms are calculated. The amount of adsorbed polymer increases without limit and the fraction of segments in the first layer decreases to zero with increase in molecular weight and solution concentration. The root‐mean‐square distance of segments from the interface is also calculated and is found to vary approximately proportional to the square root of the molecular weight, in good agreement with experiment.