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高分子链的构象性质是高分子研究中的重要研究对象。当高分子链受限于各种微腔中时,链的构象熵与微腔的形状和体积有十分密切的关系。平面壁限制条件下的高分子构象研究极多,然而在考虑高分子链穿越半径很小的纳米管时,有必要将微腔视为细长管道,而不是平面壁,因此约束在软管中的高分子链在近几年中得到了更多的重视。现有文献中主要讨论构象和能量与约束半径R之间的关系,没有考虑温度T的影响。本文采用自避行走(SAW)为模型链,利用硬球链模型模拟高分子链在无限长圆筒受限条件下的结构。模型由弹性链连接的硬球构成,球与球之间通过弹性势能函数相互作用,利用标准的Metropolis算法,通过MonteCarlo模拟,改变约束半径R和与绝对温度T成反比例关系的相关系数K,分别计算了高分子链的平均回转半径,平均末端距,平均弹性势能,能量均方涨落,能量相对涨落与R、T的关系。结果表明,圆筒受限高分子链的构像主要取决于R,在R小于某个临界值时高分子链受到明显的约束作用,当R超过临界值时高分子链变为无扰链。温度T并不明显地影响受限高分子链的构象。能量性质在R较小时主要取决于R,但R为临界受限值附近时,能量性质受T影响明显,容易出现能量和涨落的状态突变。
The conformational nature of polymer chains is an important research object in polymer research. When the polymer chain is confined to a variety of microcavities, the conformational entropy of the chains is closely related to the shape and volume of the microcavities. However, when considering the fact that polymer chains pass through nanotubes with very small radii, it is necessary to regard the microcavity as an elongated tube rather than a planar wall, so it is confined in the tube The polymer chain has gained more attention in recent years. The existing literature mainly discusses the relationship between conformation and energy and constraint radius R, without considering the influence of temperature T. In this paper, the self-avoiding walking (SAW) model chain is used to simulate the structure of polymer chains under infinite cylinder confinement. The model is composed of rigid chains connected by elastic chains. By using the standard Metropolis algorithm, Monte Carlo simulation, the constraint radius R and the correlation coefficient K inversely proportional to the absolute temperature T are calculated by the interaction between the ball and the ball. The average radius of gyration, average terminal distance, average elastic potential, energy mean square fluctuation, energy relative fluctuation and R, The results show that the conformation of the confined macromolecular chains mainly depends on R. The macromolecule chains are obviously restrained when R is less than a certain critical value. When R exceeds the critical value, the macromolecule chains become undisturbed chains. Temperature T does not significantly affect the conformation of the constrained polymer chain. The energy property mainly depends on R when R is small, but when R is near the critical limit value, the energy property is obviously influenced by T, and the energy and fluctuation state easily occur.