Quantifying Å-Scale Non-Additive Solvation at Nanoparticle Interfaces.

Area of Science:

• Physical Chemistry
• Materials Science
• Nanotechnology

Background:

• Solvent organization at solid-liquid interfaces is crucial for nanoparticle properties.
• Classical theories often oversimplify solvent behavior as a continuum, which is inadequate at the nanoscale.
• Experimental quantification of interfacial solvent structure has been challenging.

Purpose of the Study:

• To directly quantify molecular-level interfacial solvent structures in mixed solvents.
• To investigate the impact of solvent organization on nanoparticle ligand shells.
• To bridge the gap between theoretical predictions and experimental observations of nanoscale solvation.

Main Methods:

• Combined small-angle neutron scattering (SANS) with Monte Carlo real-space reconstruction.
• Analyzed solvent structures under native solution conditions.
• Quantified discrete sub-nanometer solvent clusters and their spatial organization.

Main Results:

• Identified non-linear evolution of solvent cluster abundance and organization with solvent composition.
• Observed preferential infiltration of solvent clusters into nanoparticle ligand coronas.
• Demonstrated deformation of ligand shells from spherical to anisotropic ellipsoidal shapes.
• Linked maximal solvent clustering and anisotropic deformation to bulk azeotropic composition.

Conclusions:

• Classical continuum models fail to describe observed nanoscale interfacial phenomena.
• Interfacial solvent clustering directly influences nanoparticle ligand shell symmetry.
• The developed methodology offers a versatile approach for probing and tailoring interfacial solvation effects.