Entropy-Induced Separation of Binary Semiflexible Ring Polymer Mixtures in Spherical Confinement

XL Zhou and FC Guo and K Li and LL He and LX Zhang, POLYMERS, 11, 1992 (2019).

DOI: 10.3390/polym11121992

Coarse-grained molecular dynamics simulations are used to investigate the conformations of binary semiflexible ring polymers (SRPs) of two different lengths confined in a hard sphere. Segregated structures of SRPs in binary mixtures are strongly dependent upon the number density of system (rho), the bending energy of long SRPs (K-b, long), and the chain length ratio of long to short SRPs (alpha). With a low rho or a weak K-b, long at a small ratio alpha, long SRPs are immersed randomly in the matrix of short SRPs. As rho and bending energy of long SRPs (K-b, long) are increased up to a certain value for a large ratio alpha, a nearly complete segregation between long and short SRPs is observed, which can be further characterized by the ratio of tangential and radial components of long SRPs velocity. These explicit segregated structures of the two components in spherical confinement are induced by a delicate competition between the entropic excluded volume (depletion) effects and bending contributions.

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