Phase Behavior of Polydisperse Rod-like Particles in Solution: Depletion Interactions and Isotropic-Anisotropic Transitions

This study investigates the phase behavior of polydisperse rod-like particles in solution using the Asakura and Oosawa (AO) depletion theory for rod-like macromolecules. The effect of depletion interactions between rods of different lengths on the ordering of rods is quantitatively evaluated. Numerical calculations are performed with different sizes of ellipsoids, and simulations are carried out using Gay-Berne particles in the NPT isothermal isobaric ensembles. The main objectives of this study are to (i) examine the depletion interaction between rod-like particles of different aspect ratios and (ii) analyze the isotropic–anisotropic phase transitions within the coexistence range. The results demonstrate that the properties of the anisotropic phase vary significantly with temperature, aspect ratio, and density, which is crucial for understanding the behavior of rod-like particles in solution.