The paper presents two complementary models to simulate the dynamics of dilute colloidal sedimentation and flotation near a liquid-gas interface. The first model is a two-phase field model that can be solved analytically using a perturbative approach, while the second model is a hybrid particle-phase field approach that combines a continuum phase field with discrete point particles.
The key highlights and insights are:
The two-phase field model allows for an analytical solution of the equilibrium interfacial profile, which shows excellent agreement with numerical simulations.
The presence of colloidal particles near the interface can significantly distort the interfacial profile, leading to a reduction in the liquid-gas surface tension. This reduction is monotonically decreasing with increasing particle concentration and decreasing buoyant mass of the particles.
The reduction in surface tension aligns with experimental observations, though the mechanism differs from surfactant-laden interfaces, where the particles are adsorbed into the interface.
The hybrid particle-phase field model combines the advantages of discrete particle dynamics and continuum phase field, allowing for a more comprehensive representation of the system.
The perturbative analytical solution provides a robust framework for capturing the complex dynamics of colloidal particles in fluid systems, which can be potentially extended to suspensions of active colloids near a fluid-fluid interface.
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by Alexandra J.... at arxiv.org 10-01-2024
https://arxiv.org/pdf/2407.18850.pdfDeeper Inquiries