Surface-curvature-amplified conformational disorder in alkyl capping ligands has been observed previously when the nanoparticle radii approach the ligand length. Herein, sum frequency generation studies on oleic-acid-capped nanoplates show that even on faceted surfaces with dimensions tens of times greater than the ligand length a significant proportion of gauche defects exist in the capping layer. The molecular disorder on the nanosized facets is attributed to a facet-edge effect, which is diminished when increasing the facet size or assembling the nanofacets side to side. This feature is further explored to probe the self-assembly dynamics of nanoplates.
Keywords: capping ligands; conformational disorder; nanofacet; self-assembly; sum frequency generation.