Similar hydrodynamic transitions in adsorbed layers of backbone-adsorbing and end-adsorbing polymers

Results concerning the hydrodynamic thickness of adsorbed polymer layers were reanalyzed to reveal a near-universal dependence on surface loading at low and intermediate concentrations. This was found for three poly(ethylene oxide) samples with varying end group-surface attractions (hydrophobicity). The finding detracts from the previous interpretation of a pancake-to-brush transition for polymers containing end groups with strong surface affinity, because the control samples without hydrophobic end groups experienced an equally sharp transition in hydrodynamic thickness as a function of surface coverage.