Phase Diagram of Flexible Polymers with Quenched Disordered Charged Monomers
| Autor: | Rodrigues, B. B., Rocha, J. C. S., Costa, B. V. |
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| Rok vydání: | 2021 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1016/j.physa.2022.127787 |
| Popis: | Recent advances in Generalized Ensemble simulations and microcanonical analysis allowed the investigation of structural transitions in polymer models over a broad range of local bending and torsion strengths. It is reasonable to argue that electrostatic interactions play a significant role in stabilizing and mediating structural transitions in polymers. We propose a bead-spring polymer model with randomly distributed charged monomers interacting via a screened Coulomb potential. By combining the Replica Exchange Wang-Landau (REWL) method with energy-dependent monomer updates, we constructed the hyperphase diagram as a function of temperature ($T$) and charged monomer concentration ($\eta$). The coil-globule and globular-solid transitions are respectively second and first order for the entire concentration range. However, above a concentration threshold of $\eta=80\%$, electrostatic repulsion hinders the formation of solid and liquid globules, and the interplay between enthalpic and entropic interactions leads to the formation of liquid pearl-necklace ad solid helical structures. The probability distribution, $P(E,T)$, indicates that at high $\eta$, the pearl-necklace liquid phase freezes into a stable solid helix-like structure with a free energy barrier higher than the freezing globule transition at low $\eta$. Comment: 10 pages, 8 figures |
| Databáze: | arXiv |
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