Molecular Simulation Studies of the Isotropic-to-Nematic Transition of Rod-like Polymers in the Bulk and Under Confinement

In this research work, we conduct extensive Monte Carlo simulations to investigate the factors that affect the isotropic-to-nematic transition [1,2] of hard colloidal polymers in bulk and under various conditions of confinement. Polymers are represented as linear chains of tangent hard spheres of uniform length, with the stiffness being controlled by a bending potential leading to rod-like configurations [3]. Confinement is realized through the presence of flat, parallel and impenetrable walls in one, two or three dimensions [4], and periodic boundary conditions are applied in the unconstrained dimensions. All simulations are performed through the Simu-D software, composed of conventional and advanced, chain-connectivity-altering Monte Carlo algorithms [5].

The local and global structure of the computer-generated system configurations are gauged through the Characteristic Crystallographic Element (CCE) norm [6] and the long-range (nematic) order parameter [1]. Distinct factors, including chain length and stiffness, confinement and packing density are found to profoundly affect the isotropic-to-nematic transition at the level of chains, and the establishment of close-packed crystallites at the level of monomers.

[1] D. Andrienko, J. Mol. Liq. 267, 520 (2018).

[2] S. A. Egorov, A. Milchev, and K. Binder, Polymers 8, 296 (2016).

[3] D. Martínez-Fernandez et al., Polymers 15, 551 (2023).

[4] P. Ramos et al., Polymers 13, 1352 (2021).

[5] M. Herranz et al., Int. J. Mol. Sci. 22, 12464 (2021).

[6] P. M. Ramos et al., Crystals 10, 2073 (2020).