Poly(p-benzamide) with a defined molecular weight and a low polydispersity and a block copolymer containing this well-defined aramide was synthesized. Phenyl 4-aminobenzoate, which would yield poly(p-benzamide), did not polymerize under the conditions of chain-growth polycondensation. However, phenyl 4-(4-octyloxybenzylamino)benzoate (1b) polymerized at room temperature in the presence of base and phenyl 4-nitrobenzoate (2) as an initiator in a chain-growth polycondensation manner to give well-defined aromatic polyamides having the 4-octyloxybenzyl groups as a protecting group on nitrogen in an amide. It was confirmed by a model reaction that deprotection of this protecting group proceeded completely with trifluoroacetic acid (TFA) without breaking the amide linkage. The utility of this approach to poly(p-benzamide) with a low polydispersity was demonstrated by the synthesis of block copolymers. Thus, phenyl 4-(octylamino)benzoate (1a) polymerized in the presence of 2 and base, followed by addition of 1b and base to the reaction mixture of the prepolymer to yield the block copolymer of 1a and 1b with a controlled molecular weight and a low polydispersity. The block copolymer was treated with TFA, resulting in a soluble block copolymer of poly(N-octyl-p-benzamide) and poly(p-benzamide). The SEM images of the supramolecular assemblies of the block copolymer showed mum-sized bundles and aggregates of flake structures.

Polycondensation of phenyl 4‐(octylamino)benzoate (1) in the presence of diphenyl terephthalate (2) as a difunctional initiator proceeded in a bidirectional propagation from 2. This polycondensation was applied to the synthesis of poly(ethylene glycol) (PEG)–aromatic polyamide–PEG triblock copolymer (4) as a new, well‐defined coil‐rod‐coil triblock copolymer.

Poly(p‐benzamide) with a defined molecular weight and a low polydispersity and block copolymers containing this well‐defined aramide was synthesized. Phenyl 4‐(4‐octyloxybenzylamino)benzoate (1b) polymerized at room temperature in the presence of base and phenyl 4‐nitrobenzoate (2a) as an initiator in a chain‐growth polycondensation manner to give well‐defined aromatic polyamides having the 4‐octyloxybenzyl groups as a protecting group on nitrogen in an amide. It was confirmed by a model reaction that deprotection of this protecting group proceeded completely with trifluoroacetic acid (TFA) without breaking the amide linkage. The utility of this approach to poly(p‐benzamide) with a low polydispersity was demonstrated by the synthesis of block copolymers of poly(p‐benzamide) and poly(N‐octyl‐p‐benzamide) or poly(ethylene glycol). The SEM images of the supramolecular assemblies of the former block copolymer showed μm‐sized bundles and aggregates of flake structures.

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