Surface Ligands Dictate the Mechanical Properties of Inorganic Nanomaterials

SM Rehn and TM Gerrard-Anderson and Y Chen and P Wang and T Robertson and TP Senftle and MR Jones, ACS NANO, 17, 6698-6707 (2023).

DOI: 10.1021/acsnano.2c12497

The ability for organic surface chemistry to influence the properties of inorganic nanomaterials is appreciated in some instances but is poorly understood in terms of mechanical behavior. Here we demonstrate that the global mechanical strength of a silver nanoplate can be modulated according to the local binding enthalpy of its surface ligands. A continuum-based core-shell model for nanoplate deformation shows that the interior of a particle retains bulk-like properties while the surface shell has yield strength values that depend on surface chemistry. Electron diffraction experiments reveal that, relative to the core, atoms at the nanoplate surface undergo lattice expansion and disordering directly related to the coordinating strength of the surface ligand. As a result, plastic deformation of the shell is more difficult, leading to an enhancement of the global mechanical strength of the plate. These results demonstrate a size-dependent coupling between chemistry and mechanics at the nanoscale.

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