Coverage-dependent morphology of PEGylated lysozyme layers adsorbed on silica

► Neutron reflection to study mono-PEG-lysozyme adsorption at silica/water interface. ► Two surface concentrations on both sides of a transition in adsorption isotherm. ► Low surface concentration: high PEG volume occupancy of surface proximal region. ► High surface concentration: PEG chains extend further into solution. ► Findings provide opportunities for design of chromatographic separation protocols.