Strain-Mediated Friction Tuning of Atomic Step Edges by Carbon Chain Grafting

Area of Science:

• Materials Science
• Tribology
• Nanotechnology

Background:

• Two-dimensional (2D) layered materials exhibit superlubricity on basal planes.
• High friction and stress at step edges hinder macroscale applications of 2D materials.

Purpose of the Study:

• To develop a strategy for friction reduction at step edges of 2D materials.
• To investigate the mechanism of friction reduction at graphene step edges.

Main Methods:

• Hydrogen plasma treatment to introduce carbon chains (dodecyl chains) at graphene step edges.
• Molecular dynamics simulations to analyze interfacial strain and friction.

Main Results:

• Grafting dodecyl chains reduced friction at single-layer graphene step edges by up to 67%.
• Simulations revealed that grafted carbon chains alleviate interfacial strain concentration, the primary cause of friction reduction.

Conclusions:

• Selective functionalization of atomic step edges is a viable strategy for friction reduction.
• Understanding and mitigating strain concentration at step edges is crucial for achieving superlubricity in 2D materials.