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Phase Behavior and Self-Assembly of Semiflexible Polymers in Poor-Solvent Solutions†
Macromolecules ( IF 5.1 ) Pub Date : 2024-09-04 , DOI: 10.1021/acs.macromol.4c01111 Tobia Arcangeli 1, 2 , Tatjana Škrbić 1 , Somiealo Azote 3 , Davide Marcato 4 , Angelo Rosa 4 , Jayanth R. Banavar 5 , Roberto Piazza 2 , Amos Maritan 6, 7 , Achille Giacometti 8, 9
Macromolecules ( IF 5.1 ) Pub Date : 2024-09-04 , DOI: 10.1021/acs.macromol.4c01111 Tobia Arcangeli 1, 2 , Tatjana Škrbić 1 , Somiealo Azote 3 , Davide Marcato 4 , Angelo Rosa 4 , Jayanth R. Banavar 5 , Roberto Piazza 2 , Amos Maritan 6, 7 , Achille Giacometti 8, 9
Affiliation
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Using Langevin dynamics complemented by Wang–Landau Monte Carlo simulations, we study the phase behavior of single and multiple semiflexible polymer chains in solution under poor-solvent conditions. In the case of a single chain, we obtain the full phase diagram in the temperature-bending rigidity (stiffness) plane and we provide connections with a classical mean field result on a lattice as well as with past results on the same model. At low bending rigidity and upon cooling, we find a second-order coil-globule transition, followed by a subsequent first-order globule-crystal transition at lower temperatures. The obtained crystals have the shape of a twisted rod, whose length increases with the increase of the stiffness of the chain. Above a critical value of the stiffness, we also find a direct first-order globule-crystal transition, with the crystal having the form of a twisted toroid. Close to the triple point, we find a region with isoenergetic structures with frequent switching from rods to toroids, with the toroid eventually becoming the only observed stable phase at a higher stiffness. The model is then extended to many thermally equilibrated chains in a box, and the analogous phase diagram is deduced where the chains are observed to first fold into a globule bundle at low stiffness upon cooling and then rearrange into a nematic bundle via a nucleation process involving an isotropic–nematic transition. As in the single-chain counterpart, above a critical stiffness, the chains are observed to undergo a direct transition from a gas of isotropically distributed chains to a nematic bundle as the temperature decreases, in agreement with recent suggestions from mean field theory. The consequences of these findings for the self-assembly of biopolymers in solutions are discussed.
中文翻译：
半柔性聚合物在不良溶剂溶液中的相行为和自组装†
利用 Langevin 动力学并辅以 Wang-Landau 蒙特卡罗模拟，我们研究了贫溶剂条件下溶液中单个和多个半柔性聚合物链的相行为。在单链的情况下，我们获得了温度弯曲刚性（刚度）平面中的完整相图，并提供了与晶格上的经典平均场结果以及同一模型上的过去结果的连接。在低弯曲刚度和冷却时，我们发现二阶线圈-球体转变，随后在较低温度下发生一阶球体-晶体转变。所得晶体具有扭杆形状，其长度随着链条刚度的增加而增加。在刚度的临界值以上，我们还发现了直接的一阶球体-晶体转变，晶体具有扭曲的环形形状。在三相点附近，我们发现了一个具有等能结构的区域，该区域经常从棒状结构切换到环形结构，环形结构最终成为唯一观察到的更高刚度的稳定相。然后将该模型扩展到盒子中的许多热平衡链，并推导出类似的相图，其中观察到链在冷却时首先折叠成低刚度的球束，然后通过涉及的成核过程重新排列成向列束各向同性-向列相转变。与单链对应物一样，在临界刚度以上，随着温度降低，观察到链经历从各向同性分布链的气体直接转变为向列束，这与平均场理论的最新建议一致。 讨论了这些发现对溶液中生物聚合物自组装的影响。
更新日期：2024-09-04
中文翻译：
半柔性聚合物在不良溶剂溶液中的相行为和自组装†
利用 Langevin 动力学并辅以 Wang-Landau 蒙特卡罗模拟，我们研究了贫溶剂条件下溶液中单个和多个半柔性聚合物链的相行为。在单链的情况下，我们获得了温度弯曲刚性（刚度）平面中的完整相图，并提供了与晶格上的经典平均场结果以及同一模型上的过去结果的连接。在低弯曲刚度和冷却时，我们发现二阶线圈-球体转变，随后在较低温度下发生一阶球体-晶体转变。所得晶体具有扭杆形状，其长度随着链条刚度的增加而增加。在刚度的临界值以上，我们还发现了直接的一阶球体-晶体转变，晶体具有扭曲的环形形状。在三相点附近，我们发现了一个具有等能结构的区域，该区域经常从棒状结构切换到环形结构，环形结构最终成为唯一观察到的更高刚度的稳定相。然后将该模型扩展到盒子中的许多热平衡链，并推导出类似的相图，其中观察到链在冷却时首先折叠成低刚度的球束，然后通过涉及的成核过程重新排列成向列束各向同性-向列相转变。与单链对应物一样，在临界刚度以上，随着温度降低，观察到链经历从各向同性分布链的气体直接转变为向列束，这与平均场理论的最新建议一致。 讨论了这些发现对溶液中生物聚合物自组装的影响。
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