Well-defined AbBA triblock bottlebrush with poly(N,N-dimethyl acrylamide) (PAm) as A block and polyacrylate, densely grafted with poly(tert-butyl acrylate)-block-polystyrene (PBA-b-PS), as brush bB block is prepared by controlled radical polymerization and click chemistry. The triblock copolymer with a composition of PAm200-b-b(PBA(14)-b-PS47)(167)-b-PAm200 is obtained and is further transformed into PAm200-b-b(PAA(14)-b-PS47)(167)-b-PAm200 by hydrolysis of the PBA segment into poly(acrylic acid) (PAA). In a mixture of N, N-dimethylformamide (DMF) and methanol, a poor solvent of bB block, PAm200-b-b(PAA(14)-b-PS47)(167)-b-PAm200 self-assembled into disk-like platelets, which have an internal lamellar structure by further microphase-separation of PAA-b-PS branches in 2D. Moreover, Ag nanoparticles are aligned by PAA segments along the disk to form a pattern.