Here we note the polypeptoid brush modified surfaces are not hydrophobic; however, it is possible to further expand the tunable range of surface energy with grafted polypeptoids by introducing more hydrophobic side chains such as longer alkyl or fluorinated side chains. Figure . The surface energy of Si substrates, as evidenced by different static water contact angles, is modified accordingly by the grafted polypeptoid brush monolayers depending on the monomer chemistry and monomer composition. See Table for chemical structures of the polypeptoids.