Triphilic Block Copolymers: Synthesis, Aggregation Behavior and Interactions with Phospholipid Membranes

Novel PPO-based amphiphilic diblock copolymer and triphilic multiblock copolymer analogues of the architectures BA, CBA, and CABAC have been successfully synthesized by combination of atom transfer radical polymerization (ATRP) and copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) 'click' post-polymerization reaction. The A, B, and C components of the block copolymers are formed by hydrophilic poly(glycerol monomethacrylate) (PGMA), lipophilic poly(propylene oxide) (PPO), and perfluoroalkyl segment, respectively. Their critical micelle concentrations in water are determined from surface tension measurements. Their aggregation behavior in aqueous medium is studied by temperature-dependent (1)H- and (19)F NMR spectroscopy. The presence of the perfluoro segments within the micelle cores of the triphilic block copolymers enhanced 3-4 folds their solubilization capacity of tetrafluorobenzene compared to micelle cores without the perfluoro segments. It is found that the triphilic copolymer inserts into lipid membranes and induces lateral demixing between the two homologue lipids in the temperature range of the phase transition of the lipids.