Properties of aqueous solutions of hydrophobically modified polyethylene imines in the absence and presence of sodium dodecylsulfate

► Polyethylene imines with pendant alkyl groups show pronounced surface activity. ► Polyelectrolyte hydrophobicity can be tuned by increasing the alkyl chain length. ► Hydrophobic polyethylene imines interact strongly with sodium dodecylsulfate (SDS). ► At high c(SDS), polyethylene imines form aggregated and random-coil polymer chains.