Effect of Hydrophilic Block-A Length Tuning on the Aggregation Behavior of α,ω-Perfluoroalkyl End-Capped ABA Triblock Copolymers in Water

The tremendous influence of hydrophilic block length tuning on the aggregation behavior of novel water-soluble triphilic (i.e., hydrophilic, lipophilic, and fluorophilic) α,ω-perfluoroalkyl end-capped symmetric ABA triblock copolymers is demonstrated. The hydrophilic A and lipophilic B blocks are comprised of poly(glycerol monomethacrylate) (PGMA) and poly(propylene oxide) (PPO), respectively. The fluorophilic component consists of two “clicked” perfluoroalkyl segments (C9F19) at the ends of the block copolymers. Two of the different block copolymers synthesized, namely F9-PGMA24-PPO27-PGMA24-F9 (PB1) and F9-PGMA42-PPO27-PGMA42-F9 (PB2), differ only in the degree of polymerization of the hydrophilic PGMA blocks. Their critical micelle concentrations in water are determined from surface tension measurements. The aggregation behavior in aqueous medium studied by 19F NMR spectroscopy reveals that the fluorocarbon component forms part of the micelle corona of PB1, while in PB2 it aggregates to form part of th...