聚电解质链在柱状受限下的构象转变  

The configurational transition of polyelectrolyte chain confined in a cylinder

作　　者：高菊先 丁斌远 何林李[1] GAO Juxian;DING Binyuan;HE Linli(Department of Physics,Wenzhou University,Wenzhou 325035,Zhejiang Province,China)

机构地区：[1]温州大学数理学院,浙江温州325035

出　　处：《浙江大学学报（理学版）》2023年第5期580-587,共8页Journal of Zhejiang University（Science Edition）

基　　金：国家自然科学基金资助项目(22273067).

摘　　要：采用粗粒化分子动力学模拟方法,研究了受限于圆柱体内的聚电解质链的构象行为。通过计算链平均回旋半径、平均持久长度和平均形状因子等物理量,重点探究反离子价态、链刚性和受限孔径等对聚电解质链尺寸和构象转变的影响。结果表明,受限聚电解质链可形成稳定的棒状、球状、折叠链状和环状结构。尤其在三价反离子诱导下,半刚性聚电解质链可形成稳定的环状结构,并由切向相关函数表征。通过统计反离子分布,进一步探讨了聚电解质链和离子凝结的机制。同时讨论了环的成核和生长动力学特征,为进一步揭示生物大分子在有限空间内的构象行为提供了理论指导。The configurational transition of polyelectrolyte chain confined in a cylinder was studied by means of coarse-grained molecular dynamics simulation.Specifically,the effects on the size and configuration transition of polyelectrolyte chain under the parameters of counterion valence,chain stiffness and confinement radius were studied by calculating the average radius of gyration,average persistence length,and average shape factor.It has been found that there are stable rod-like,globular,folded-chain and ring structures in confined space.In the case of trivalent counterions,the polyelectrolyte chain with moderate stiffness forms a stable ring structure,which can be well characterized by a tangent correlation function.The mechanism of condensation of polyelectrolyte chain and counterion is further explored by statistical analysis of polyelectrolyte chain and counterions distribution.Finally,the kinetic characteristics of the nucleation and growth of the ring structure are discussed,and the results agree with the experimental results.The results can provide a deep insight about the configurational behaviors of biological macromolecules in confined spaces.

关 键 词：分子动力学 受限 链刚性 反离子价态 构象转变 

分 类 号：O469[理学—凝聚态物理]