Compatibility of Polypeptoid Brushes with Lithographic Nanopatterning. The compatibility with lithographic patterning of the polypeptoid brush monolayers is an important attribute of this class of bioinspired, sequence-defined polymers as surface modification materials, as it will enable the generation of chemical contrast nanopatterns by design with monomer-level control. The lithographic patterning workflow adopted in this study follows a typical strategy of patterning surface modification layers on Si substrates. As shown in Figure , it involves the following steps: i) spin coating a ~40 nm PMMA resist on top of the polypeptoid brush monolayer for electron-beam lithography, with a subsequent development step; ii) reactive ion etching with oxygen plasma to transfer the pattern of the PMMA resist layer into the underlying polypeptoid brush monolayer; iii) stripping the PMMA resist and reannealing the polypeptoid brush to obtain a nanopatterned polypeptoid brush monolayer on Si substrates. AFM height profiles show that the generated line-space patterns are well-defined with sharp edges and reveal that the polypeptoid brush monolayers are ~1 nm in thickness (Figure ). With the monolayer thickness obtained from nanopatterned polypeptoid brushes, the estimated grafting density (𝜎) based on the formula 𝜎 =