Seeding method for ice nucleation under shear

Area of Science:

• Thermodynamics and Fluid Dynamics
• Materials Science and Crystallization
• Computational Physics

Background:

• Homogeneous nucleation rates are sensitive to hydrodynamic flow, but theoretical frameworks are limited.
• Classical Nucleation Theory (CNT) does not fully account for shear effects.
• Understanding shear effects is crucial for various applications, including materials processing and atmospheric science.

Purpose of the Study:

• To develop a general theoretical formalism for calculating nucleation rates in simply sheared systems.
• To extend Classical Nucleation Theory by explicitly incorporating shear rate.
• To investigate the influence of shear on ice nucleation behavior using a specific water model.

Main Methods:

• Extension of Classical Nucleation Theory to include shear rate.
• Seeded molecular dynamics simulations.
• Analysis of competing energetic and kinetic effects of shear.

Main Results:

• Identified shear regimes for ice nucleation in the mW water model.
• Defined crossover shear rates (1000-10000 s⁻¹) where nucleation rate increases with shear.
• Determined optimal shear rates (≈10⁶-10⁷ s⁻¹) for maximum nucleation at specific temperatures (235-260 K).
• Observed strong nucleation inhibition at very high shear rates (>10⁸ s⁻¹).
• Found a non-monotonic temperature dependence for optimal shear rates.

Conclusions:

• The developed formalism accurately captures shear-induced changes in nucleation rates.
• Shear can be used to control and optimize ice nucleation.
• The findings unify disparate experimental trends and provide a predictive framework for shear-influenced nucleation.