An examination of the surface-pressure isotherms in end-tethered polymer layers

End-tethered polymer layers are formed when a collection of polymers is anchored by one end to a surface, with the reminder dangling into solvent. These systems have been studied extensively both experimentally and theoretically, and numerical self-consistent field (NSCF) theory can now explain their structure very well. However, the behaviour of the surface pressure isotherms remains an unsolved problem. Kent and coworkers found that the surface pressure increases relatively weakly with polymer coverage up to a certain threshold but, beyond that, it increases much more rapidly. This rapid increase has never been explained theoretically. Recently, however, Bijsterbosch et al performed similar experiments and found no sudden increase, even well beyond the expected threshold. We provide a detailed, numerical examination of these systems and results, using NSCF theory.