Synthesis And Characterization Of Amphiphilic Diblock Copolymers Based On PDMAEMA And Their Solution Behaviors

This paper is focused on the synthesis and characterization of amphiphilic diblock copolymers based on poly[2-(N, N-dimethylamino)ethyl methacrylate] (PDMAEMA or PDMA) and their solution behaviors. The monomers used in this work include DMA, stearyl methacrylate (SMA), 2, 2, 2-trifluoroethyl methacrylate (TFMA), 2, 2, 3, 4, 4, 4-hexafluorobutyl methacrylate (HFMA) and 2, 2, 3, 3, 4, 4, 5, 5-octafluoropentyl methacrylate (OFMA).(1) Synthesis of Amphiphilic Diblock Copolymers PDMA-b-PSMA and Their Self-assembly BehaviorAmphiphilic diblock copolymers, PDMA-b-PSMA, were prepared by reversible addition-fragmentation chain transfer (RAFT) copolymerization. The composition and chemical structures of (co)polymers were confirmed by the measurements of 1H NMR spectroscopy and gel permeation chromatography (GPC). The self-aggregating morphologies of amphiphilic diblock copolymers in mixed solvent were investigated by transmission electron microscopy (TEM) and dynamic light scattering (DLS). It was found that both the morphologies and aggregating particle size resulted from the copolymers depended on the variation of pH values, the lengths of the hydrophobic PSMA chains, and the weight ratio of THF/water mixed solvent.(2) Synthesis of Fluorinated Amphiphilic Diblock Copolymers PDMA-b-P(T, H and O)FMA and Their Solution Behaviors Three kinds of well-defined fluorinated diblock copolymers, PDMA-b-P(T, H and O)FMA, have been synthesized successfully via oxyanion-initiated polymerization. The composition and chemical structure of these fluorinated copolymers were confirmed by 1H NMR, 19F NMR spectroscopy and gel permeation chromatography (GPC) techniques. The solution behaviors of these fluorinated copolymers were investigated by the measurements of surface tension, dynamic light scattering (DLS), and UV spectrophotometer. The results indicate that these fluorinated copolymers possess relatively high surface activity, especially at neutral media. Moreover, the DLS and UV measurements showed that these fluorinated diblock copolymers possess distinct pH/temperature-responsive properties, depending not only on the PDMA segment, but also on the fluoroalkyl structure of the FMA units.