一种模型聚乙烯的球状相和卷曲相中的结。

Knots in globule and coil phases of a model polyethylene.

作者信息

Virnau Peter, Kantor Yacov, Kardar Mehran

机构信息

Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307, USA.

出版信息

J Am Chem Soc. 2005 Nov 2;127(43):15102-6. doi: 10.1021/ja052438a.

DOI:10.1021/ja052438a

PMID:16248649

Abstract

We examine the statistics of knots with numerical simulations of a simplified model of polyethylene. We can simulate polymers of up to 1000 monomers (each representing roughly three CH(2) groups), at a range of temperatures spanning coil (good solvent) and globule (bad solvent) phases. We quantify the abundance of knots in the globule phase and in confined polymers, and their rarity in the swollen phase. Since our polymers are open, we consider (and test) various operational definitions for knots, which are rigorously defined only for closed chains. We also associate a typical size with individual knots, which are found to be small (tight and localized) in the swollen phase but large (loose and spread out) in the dense phases.

摘要

我们通过对聚乙烯简化模型的数值模拟来研究纽结的统计特性。我们能够在跨越卷曲（良溶剂）和球状（不良溶剂）相的一系列温度下，模拟多达1000个单体的聚合物（每个单体大致代表三个CH₂基团）。我们量化了球状相和受限聚合物中纽结的丰度，以及它们在溶胀相中出现的稀少程度。由于我们的聚合物是开放的，我们考虑（并测试）了纽结的各种操作定义，纽结仅针对闭合链有严格定义。我们还为单个纽结赋予了一个典型尺寸，发现在溶胀相中纽结较小（紧密且局部化），而在致密相中较大（松散且分散）。