Indentation of graphene nano-bubbles

Area of Science:

• Materials Science
• Nanotechnology
• Computational Physics

Background:

• Graphene nano bubbles are novel structures with potential applications.
• Understanding their mechanical failure is crucial for material design.
• The behavior of confined noble gases within nanomaterials is not fully understood.

Purpose of the Study:

• To investigate the mechanical failure of graphene nano bubbles under AFM tip indentation.
• To explore the influence of different noble gases (He, Ne, Ar) on bubble stability.
• To analyze the state and pressure of gases confined within nano bubbles at varying temperatures.

Main Methods:

• Utilized molecular dynamics simulations to model the indentation process.
• Simulated graphene nano bubbles filled with helium, neon, and argon.
• Analyzed failure points using the Föppl-von Kármán (FvK) number from thin shell elasticity theory.

Main Results:

• Graphene nano bubble failure points correlate with the FvK number, similar to viral shells.
• Helium exists as a liquid, while neon and argon are solid within bubbles at room temperature, despite sub-melting pressures.
• Hydrostatic pressure inside trapped gases increases at lower temperatures compared to room temperature.

Conclusions:

• The mechanical failure of graphene nano bubbles can be characterized by elasticity theory.
• Noble gas state (liquid/solid) within nano bubbles is influenced by confinement and temperature.
• Temperature significantly impacts the hydrostatic pressure of confined gases in graphene nano bubbles.