Insights into the Biomimetic Synthesis of 2D ZnO Nanomaterials through Peptoid Engineering

Achieving predictable biomimetic crystallization using sequence-defined synthetic molecules in mild conditions represents a long-standing challenge in materials synthesis. Herein we report a peptoid-based approach for biomimetic control over the formation of nanostructured ZnO materials in ambient aqueous conditions. A series of two-dimensional (2D) ZnO nanomaterials have been successfully obtained using amphiphilic peptoids with different numbers, ratios, and patterns of various hydrophilic and hydrophobic side chains. By investigating the relationship between peptoid hydrophobicity and the thickness of the resultant ZnO nanomaterials, we found the critical role of peptoid hydrophobicity in the peptoid-controlled ZnO formation. Our results suggest that tuning the hydrophobicity of peptoids can be used to moderate peptoid-ZnO surface interactions, thus controlling the formation of ultrathin (<2.5 nm) 2D ZnO nanomaterials. The peptoid-controlled formation of ZnO nanomaterials was further investigated using ultrasmall-angle X-ray scattering (USAXS). Our work suggests a new approach to synthesizing 2D metal oxide nanomaterials using sequence-defined synthetic molecules.