Foldecture as a Core Material with Anisotropic Surface Characteristics

Abstract

The synthesis of microscale, polyhedrally shaped, soft materials with anisotropic surface functionality by a bottom-up approach remains a significant challenge. Herein we report a microscale molecular architecture (foldecture) with facet-dependent surface characteristics that can potentially serve as a well-defined catalytic template. Rhombic rod shaped foldectures with six facets were obtained by the aqueous self-assembly of helical β-peptide foldamers with a C-terminal carboxylic acid. An analysis of the molecular packing by X-ray diffraction revealed that carboxylic acid groups were exposed exclusively on the two (001) rhombic facets due to antiparallel packing of the helical peptides. A surface energy calculation by molecular dynamics simulation was performed to provide a plausible explanation for the development of anisotropy during foldecture formation. The expected facet-selective surface properties of the foldecture were experimentally confirmed by selective deposition of metal nanoparticles on the (001) facets, leading to a new class of sequentially constructed, heterogeneous "foldecture core" materials.