Molecular Bottlebrushes with Polypeptide Backbone Prepared via Ring‐Opening Polymerization of NCA and ATRP

Abstract A new type of molecular bottlebrush with poly‐ L ‐lysine (PLL) as backbone was synthesized via ROP followed by ATRP. A Nϵ‐bromoisobutyryl functionalized Nα‐CBZ‐ L ‐lysine was firstly synthesized and converted in polymerizable α‐amino acid N‐carboxyanhydride (NCA), which was then polymerized using Ni(0) transition metal complex to give well‐defined bromo‐functionalized homopolypeptide (PBrLL), from which we prepared two types of polypeptide bottlebrushes with polystyrene and poly(oligoethylene glycol methacrylate) as side‐chains. PBrLL macroinitiator was demonstrated to have high initiation efficiency for ATRP, which allowed good control over side‐chain length. CD and FTIR characterization revealed that both PBrLL macroinitiator and PLL backbone of bottlebrushes adopted α‐helical conformation in appropriate solvents.