Polyetylenimine (PEI) adsorption to a DMPG lipid-monolayer in the presence of iron salts and EDTA

Branched PEI is adsorbed from 2 mmol/L solution onto a negatively charged DMPG monolayer at the air/water interface from a solution with 2 mmol/L FeSO4. With X-ray reflectivity it is found that the adsorbed PEI layer contains iron. Compared to PEI adsorbed from clean water the thickness is increased by a factor three to four. It is suggested that cooperative bonds stabilize iron ions within the PEI layer.