Dynamical scaling of coarse-grained ionic liquid under shear flow.

Area of Science:

• Materials Science
• Computational Chemistry
• Chemical Engineering

Background:

• Room-temperature ionic liquids possess unique properties suitable for non-equilibrium material processing.
• Shear flow is a critical non-equilibrium condition for studying material behavior.

Purpose of the Study:

• To investigate the shear dependence of all-atom and coarse-grained (CG) models of [C4mim]+[PF6]- ionic liquids.
• To identify critical shear rates and understand the limitations of CG models under non-equilibrium conditions.

Main Methods:

• Molecular dynamics simulations were employed for both all-atom and CG models.
• Analysis focused on structural distortion, molecular orientation, and dynamical properties under varying shear rates.

Main Results:

• Both all-atom and CG models showed similar trends in structural and orientational changes with increasing shear.
• A high critical shear rate was identified beyond which CG dynamical rescaling effects plateaued.
• The CG model's speed-up factor decreased with shear, stabilizing at a lower value at high shear rates.

Conclusions:

• CG models offer valuable insights into shear-induced phenomena in ionic liquids but have limitations at high shear rates.
• The identified critical shear rate is crucial for understanding the regime where external forces dominate CG model behavior.
• Findings guide the effective application of CG models for simulating ionic liquid-based processes.