Synthesis of Amphiphilic ABCBA‐Type Pentablock Copolymer from Consecutive ATRPs and Self‐Assembly in Aqueous Solution

Abstract

AbstractSummary: A novel amphiphilic ABCBA‐type pentablock copolymer with properties that are sensitive to temperature and pH, poly(2‐dimethylaminoethyl methacrylate)‐block‐poly(2,2,2‐trifluoroethyl methacrylate)‐block‐poly(ε‐caprolactone)‐block‐poly(2,2,2‐ trifluoroethyl methacrylate)‐block‐poly(2‐dimethylaminoethyl methacrylate) (PDMAEMA‐ b‐PTFEMA‐b‐PCL‐b‐PTFEMA‐b‐PDMAEMA), was synthesized via consecutive atom transfer radical polymerizations (ATRPs). The copolymers obtained were characterized by gel permeation chromatography (GPC) and 1H nuclear magnetic resonance (NMR) spectroscopy, respectively. The aggregation behaviors of the pentablock copolymers in aqueous solution with different pH (pH = 4.0, 7.0 and 8.5) were studied. Transmission electron microscopic images revealed that spherical micelles from self‐assembly of the pentablock copolymer were prevalent in all cases. The mean diameters of these micelles increased from 34, 46, to 119 nm when the pH of the aqueous solution decreased from 8.5, 7.0, to 4.0, respectively.