This Letter seeks to understand the impact of ABA amphiphilic copolymers on liposomes concerning their stability, bilayer permeability and bilayer phase transition. Results show that the hybrid vesicles have substantially increased shelf stability, resistance against rupture and fusion, and unique permeation behavior. Discussion is carried out on the possible mechanisms associated with bilayer structural changes, which the hydrophobic B block of the copolymer serves as a spacer and fills the voids between the lipids and the hydrophilic A block provides 'arms' in the aqueous phase. A longer hydrophilic chain length provided enhanced vesicle stability relative to a shorter chain length. (C) 2014 Elsevier B.V. All rights reserved.