Nitroxide-mediated polymerization to form symmetrical ABA triblock copolymers from a bidirectional alkoxyamine initiator

Abstract Bidirectional alkoxyamine 2 was synthesized and used as the initiator in the polymerization of styrene (S), n -butyl acrylate ( n BA), t -butyl acrylate ( t BA), isoprene (I), and dimethylacrylamide (DMA). A variety of symmetrical ABA triblock copolymers were prepared, ranging in size from 5 to 59 kDa. Kinetics studies and gel permeation chromatography (GPC) confirmed the “living” nature of these polymerizations. Trifluoroacetic acid was used to convert the P t BA blocks of these polymers into poly(acrylic acid) (PAA) blocks, forming ABA amphiphilic triblock copolymers. AFM images of PAA- b -P n BA- b -PAA and PAA- b -PS- b -PAA triblock copolymers ionized by the addition of 2,2′-(ethylenedioxy)bis(ethylamine) show evidence of self-assembly.