溶液中柔性树枝状高分子的分子动力学模拟

高等学校化学学报 ›› 2010, Vol. 31 ›› Issue (1): 199.

溶液中柔性树枝状高分子的分子动力学模拟

张国梁1,2, 卢宇源1, 宋建晖1,2, 石彤非1

1. 中国科学院长春应用化学研究所, 高分子物理与化学国家重点实验室, 长春 130022;
2. 中国科学院研究生院, 北京 100049

收稿日期:2009-03-06 出版日期:2010-01-10 发布日期:2010-01-10
通讯作者: 石彤非, 男, 博士, 副研究员, 主要从事高分子薄膜和溶液的相行为及转变行为的实验和理论模拟研究. E-mail: tfshi@ciac.jl.cn
基金资助:
国家自然科学基金(批准号: 20774096)、国家自然科学基金重点项目(批准号: 20734003)和国家自然科学基金创新研究群体科学基金(批准号: 50621302)资助.

Molecular Dynamics Simulation and Static Properties of Flexible Dendrimers in Solution

ZHANG Guo-Liang1,2, LU Yu-Yuan1, SONG Jian-Hui1,2, SHI Tong-Fei1*

1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China;
2. Graduate University of the Chinese Academy of Sciences, Beijing 100049, China

Received:2009-03-06 Online:2010-01-10 Published:2010-01-10
Contact: SHI Tong-Fei. E-mail: tfshi@ciac.jl.cn
Supported by:
国家自然科学基金(批准号: 20774096)、国家自然科学基金重点项目(批准号: 20734003)和国家自然科学基金创新研究群体科学基金(批准号: 50621302)资助.

摘要/Abstract

摘要：

采用分子动力学模拟方法研究了柔性树枝状高分子在无热溶剂中的静态和动态行为. 模拟结果表明: 在分子尺寸和回转半径Rg满足标度律Rg~N1/5(G+1)2/5P2/5(其中N为树枝状分子的聚合度, G为代数, P为链节长度, g为子代代数)时; 随着代数的增加, 树枝状分子和硬球的静态结构因子相似, 表明其内部结构发生了由“类星形”向“近球形”转化. 随着树枝状分子代数和链节长度的增加, 出现了“单元”(Monomer)密度几乎不变的区域. 树枝状分子的回折能力随着链节长度的增加而增强, 随着代数的增加而减弱. 树枝状分子各子代的运动能力不同, 与内层子代相比, 外层子代在短时间内扩散较慢, 但其松弛较快. 相对于Rouse指数, 树枝状分子“单元”运动的标度更接近Zimm指数.

关键词: 分子动力学模拟; 树枝状高分子; Zimm指数

Abstract:

We have performed molecular dynamics simulation to study the structural and dynamic properties of flexible dendrimers in athermal solvent. For dendrimers′ size, simulation results show that radius of gyration Rg can be fitted by the scaling law Rg~N1/5(G+1)2/5P2/5. As the generation number increases, the calculated static structure factor approaches that of hard sphere, which reflects a transition of internal structure from “starlike” to “hard-sphere-like” conformation. As dendrimers′ generation number and spacer length increase, there exists the distinct region, in which monomer density is almost constant. The back-folding ability of the dendrimers increases as spacer length increases but decreases as generation number increases. Each shell of dendrimers has different mobility. Compared with the interior of dendrimers, the outer shells show slower diffusion behavior within a shorter time but faster relaxation. The monomer motions exhibit a scaling that is much closer to Zimm than Rouse exponents.

Key words: Molecular dynamics simulation; Dendrimer; Zimm exponent

TrendMD:

张国梁1,2, 卢宇源1, 宋建晖1,2, 石彤非1. 溶液中柔性树枝状高分子的分子动力学模拟. 高等学校化学学报, 2010, 31(1): 199.

ZHANG Guo-Liang1,2, LU Yu-Yuan1, SONG Jian-Hui1,2, SHI Tong-Fei1*. Molecular Dynamics Simulation and Static Properties of Flexible Dendrimers in Solution. Chem. J. Chinese Universities, 2010, 31(1): 199.

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