Improved methodology to compute the intrinsic friction coefficient at solid-liquid interfaces

Area of Science:

• Computational physics
• Materials science
• Physical chemistry

Background:

• The liquid-solid (L-S) interface governs friction in many systems.
• Existing methods for calculating interfacial friction have limitations, including statistical errors and bulk fluid contributions.

Purpose of the Study:

• To develop an improved methodology for computing the intrinsic friction coefficient at the L-S interface.
• To reduce statistical errors and eliminate bulk fluid contributions in friction coefficient calculations.

Main Methods:

• Utilized equilibrium molecular dynamics simulations.
• Applied an improved theoretical model based on Hansen et al. [Phys. Rev. E 84, 016313 (2011)].
• Focused calculations on interfacial particles to isolate wall-fluid interactions.

Main Results:

• The new method demonstrated smaller statistical errors compared to the original Hansen et al. procedure.
• Calculated interfacial friction solely from wall-fluid interactions, excluding bulk fluid effects.
• Validated the intrinsic nature of the friction coefficient across various interfaces, channel sizes, and against non-equilibrium molecular dynamics.

Conclusions:

• The improved methodology offers a more reliable approach to determining intrinsic interfacial friction.
• This method overcomes convergence and correlation-time ambiguities inherent in Green-Kubo-like formulations.
• Provides a robust tool for understanding and predicting friction at liquid-solid interfaces.