Well-defined diblock copolymers composed of poly(N-octylbenzamide) and polystyrene were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization of styrene with a polyamide chain transfer agent (CTA) prepared via chain-growth condensation polymerization. Synthesis of a dithioester-type macro-CTA possessing the polyamide segment as an activating group was unsatisfactory due to side reactions and incomplete introduction of the benzyl dithiocarbonyl unit. On the other hand, a dithiobenzoate-CTA containing poly(N-octylbenzamide) as a radical leaving group was easily synthesized, and the RAFT polymerization of styrene with this CTA afforded poly(N-octylbenzamide)-block-polystyrene with controlled molecular weight and narrow polydispersity.

Homopolymer-arm, block-arm, and miktoarm star polymers consisting of poly(N-octylm-benzamide) and poly(N-H-m-benzamide) were synthesized by means of a core cross-linking method. Macromonomers (MM) with the styryl terminal moiety were synthesized by chain-growth condensation polymerization of 3-(alkylamino)benzoic acid esters 1 in the presence of phenyl 4-vinylbenzoate as an initiator, and copolymerization with N,N 0 -methylenebis(acrylamide) as a divinyl monomer in the presence of 2,2 0 -azobis(isobutyronitrile) at 60 °C yielded the corresponding star polymers. In the synthesis of star polymers containing poly(N-H-m-benzamide) arms, the 4-(octyloxy)benzyl group on the amide nitrogen of the obtained star polymers was removed with trifluoroacetic acid. The number of arms per molecule, determined by multiangle laser light scattering, varied in the range of 36-100 depending on the N-alkyl group of 1 and the molecular weight of MM. The 1 H NMR spectra of the star polymers in dimethyl sulfoxide revealed that the poly(N-octyl-m-benzamide) segments and arms of the block-arm and miktoarm star polymers, respectively, were compactly packed at room temperature and became extended at higher temperatures.

Well-defined diblock condensation copolymers composed of an aromatic polyamide and an aromatic polyether have been synthesized by means of successive chain-growth condensation polymerizations. Polymerization of a polyamide monomer with an orthogonally difunctional initiator is accompanied with side reactions. On the other hand, polymerization with a monofunctional initiator afforded well-defined polyamide, which has been converted into a macroinitiator by introduction of a terminal 4-fluorobenzophenone unit. Well-defined diblock copolymers are obtained by polymerization of a polyether monomer in the presence of this macroinitiator.