Figure 4

(a–c) Calcite crystal morphologies induced by 51 μM peptoid solutions of: (a) Pep-11, (b) Pep-12 and (c) Pep-13. Peptoids with a larger number of carboxyl groups exhibit stronger reduction in the expression of the {104} faces. (d) Reverse phase HPLC data shows the relative hydrophobicities, where longer retention time indicates higher hydrophobicity (5–95% CH3CN in H2O at 1 mL/min flow rate; detailed HPLC conditions are provided in the Supporting Information). (e) Structures of peptoids Pep-11, Pep-12 and Pep-13.