The characterisation of rough particle contacts by atomic force microscopy

Area of Science:

• Materials Science
• Surface Science
• Tribology

Background:

• Understanding particle-surface interactions is key for granular material applications.
• Surface roughness significantly influences adhesion and granular flow dynamics.
• Existing methods may not fully capture micro- and nano-scale topographical effects.

Purpose of the Study:

• To develop a method for determining the effective asperity radius of curvature of particles in contact.
• To investigate the influence of particle surface topography on adhesion using Atomic Force Microscopy (AFM).
• To establish a link between contact zone topography and adhesion for granular materials.

Main Methods:

• Utilizing an Atomic Force Microscopy (AFM) reverse imaging technique.
• Analyzing the contact zone topography of glass and UO3 particles on mica substrates.
• Applying a novel method to derive effective asperity radius from topographical data.

Main Results:

• The proposed method successfully determined the effective asperity radius for glass and UO3 particles.
• Results were consistent with established contact mechanics models, despite varying surface roughness.
• The technique provided insights into how micro- and nano-roughness impact particle adhesion.

Conclusions:

• The AFM-based method offers a straightforward approach to quantify particle surface roughness effects on adhesion.
• This understanding is vital for optimizing granular flow in applications like pellet and tablet manufacturing.
• The study highlights the importance of micro/nano-topography in predicting granular material behavior.