Sedimentation of a suspension of discorectangles

• Published in: Physica A 2024-06, Vol.644, p.129837, Article 129837
• Main Authors: Lebovka, Nikolai I., Cieśla, Michał, Vygornitskii, Nikolai V.
• Format: Article
• Language: English
• Subjects: Computer simulation; Discorectangle; Sedimentation; Tactoids
• ISSN: 0378-4371; 1873-2119
• DOI: 10.1016/j.physa.2024.129837

The sedimentation of anisotropically-shaped particles (discorectangles) was studied by means of Monte Carlo (MC) simulations in two-dimensional systems. The model with continuous positional and orientational degrees of freedom was considered. During sedimentation, the particle undergoes random translational and rotational Brownian motions and downward movements controlled by gravitation. Interrelation between gravitational and random motions was determined by the Péclet number varied in the interval Pe=0.05−0.2 (i.e. random walks were dominant). The value of particle aspect ratio (the length-to-width ratio) was varied in the interval ɛ=1.1−10. In the studied systems, the initial hindered sedimentation process was followed by a consolidation process at the bottom sediment. Studies revealed the complicated sedimentation-driven self-assembly, orientational ordering, and formation of stacks (tactoids) in sediment films. Permeability of sediment films was tested using the random walker method and was characterized by diffusion coefficient through the sediment film D. The evolution of the deposit height, order parameter, and diffusion coefficient D at different values of ɛ and Pe are discussed. •Monte Carlo studies of sedimentation of discorectangles was performed.•The model accounts for continuous positional and orientational degrees of freedom.•The particle aspect ratio (the length-to-width ratio) was varied in the interval ɛ=1.1−10.•The complicated sedimentation-driven self-assembly and formation of tactoids was observed.•Permeability of sediment films was tested using the random walker method.