Edge length-dependent interlayer friction of graphene

Area of Science:

• Materials Science
• Tribology
• Nanotechnology

Background:

• Edge effects significantly impact nanoscale friction, but their precise relationship with contact edges remains poorly understood.
• Understanding these effects is crucial for applications involving nanoscale interfaces.

Purpose of the Study:

• To investigate the intrinsic effect of edge size on nanoscale friction between incommensurate graphene layers.
• To quantify the relationship between edge size and friction forces in graphene flakes.

Main Methods:

• Utilized molecular dynamics simulations to model graphene flakes on a supported graphene substrate.
• Calculated friction forces for 'inside' and 'outside' zones of a divided rectangular graphene sheet.
• Analyzed the 'equivalent friction force' by summing forces on divided sections.

Main Results:

• The sum of friction forces on divided flakes ('equivalent friction force') exceeded the friction of the original intact flake.
• This increase is attributed to additional friction generated at the newly created edges.
• The equivalent friction force demonstrated a linear proportionality to the edge size.

Conclusions:

• Nanoscale friction in graphene is intrinsically dependent on the contact edge size.
• Edge friction contributes significantly to the overall tribological behavior of nanoscale contacts.
• The findings highlight the importance of considering edge geometry in nanoscale friction studies.