Simultaneous quantification of Young's modulus and dispersion forces with nanoscale spatial resolution

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Understanding local interactions in polymers and layered materials is vital for advancements.
• Current methods for quantifying nanoscale dispersion forces are often time-consuming, destructive, or require specialized equipment.

Purpose of the Study:

• To present a novel, non-invasive method for quantifying local mechanical and dispersion properties at the nanoscale.
• To enable precise measurements of Hamaker constant and effective Young's modulus using atomic force microscopy (AFM).

Main Methods:

• Utilizes atomic force microscopy (AFM) with a vibrating cantilever.
• Combines cantilever frequency shift with contact mechanics models to derive material properties.
• Employs varying oscillation amplitudes to control the analysis length-scale, from sub-nanometric defects to homogeneous areas.

Main Results:

• Successfully quantifies local Hamaker constant and effective Young's modulus with nanometer precision.
• Validated the method on 2D materials (HBN, MoT2, WSe2) and polymer films in various environments.
• Provides the first experimental Hamaker constant measurements for HBN, MoT2, WSe2, and polymer films, aligning with theoretical predictions.

Conclusions:

• The developed AFM-based method is simple, robust, and non-invasive.
• It offers a powerful tool for characterizing van der Waals interactions in polymers and nanostructured materials.
• The technique has broad applicability in technological fields requiring fine control over material properties.