Molecular Simulations Revealing Effects of Non-concatenated Ring Topology on Phase Behavior of Symmetric Diblock Copolymers
Molecular Simulations Revealing Effects of Non-concatenated Ring Topology on Phase Behavior of Symmetric Diblock Copolymers
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分子模拟揭示非级联环拓扑对对称二嵌段共聚物相行为的影响
DOI：
10.1021/acs.macromol.3c02473
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发表时间：
2024
期刊：
影响因子：
5.5
通讯作者：
Ge, Ting
中科院分区：
文献类型：
--
作者：
Wijesekera, Andrew;Vigil, Daniel L.;Ge, Ting
非串联环聚合物的独特性体现在其分形球状构象和自相似动力学，没有长寿命的缠结网络，推动了使用环拓扑来改变嵌段共聚物的相行为的想法。由于高分子量二嵌段环聚合物的实验研究有限，对称二嵌段共聚物的大规模分子模拟被用来研究非串联环拓扑对其相行为的影响。不存在缠结网络有利于相分离动力学，表明二嵌段环聚合物的加工相对容易。相对于高斯随机游走构象，环状聚合物的更紧凑的球状构象需要更高的焓斥力来驱动层状相分离。与高斯二嵌段环聚合物有序-无序转变的平均场理论相比，模拟表明需要一种结合涨落效应和非级联拓扑不变性的新理论。在强偏析状态下，二嵌段环聚合物在层状界面附近被拉伸，但在较大长度尺度上保留了球状构象统计数据。层状间距随着两个嵌段之间的焓斥力以及二嵌段环的分子量而增加。通过考虑球状构象来修改二嵌段线性聚合物的标度参数，并很好地预测了焓斥力和分子量的依赖性。随着焓斥力的增加，层状界面变得更加尖锐。虽然该理论预测固有界面宽度不依赖于聚合物分子量或拓扑结构，但通过毛细管波加宽的表观界面宽度w随着分子量和拓扑结构而表现出轻微的变化。
The distinctiveness of nonconcatenated ring polymers, as manifested in their fractal globular conformations and self-similar dynamics with no long-lived entanglement network, propels the idea of using ring topology to transform the phase behavior of block copolymers. With limited experimental studies of high-molecular-weight diblock ring polymers, large-scale molecular simulations of symmetric diblock copolymers are used to investigate the effects of nonconcatenated ring topology on their phase behavior. The absence of an entanglement network facilitates the phase-separation kinetics, suggesting relative ease in processing diblock ring polymers. The more compact globular conformations of ring polymers with respect to the Gaussian random-walk conformations require a higher enthalpic repulsion to drive the lamellar phase separation. Compared with the mean-field theory for the order–disorder transition in Gaussian diblock ring polymers, the simulations demonstrate the necessity for a new theory incorporating both the effects of fluctuations and the topological invariance of nonconcatenation. In the strong segregation regime, diblock ring polymers are stretched near the lamellar interface but with the globular conformational statistics preserved at larger length scales. The lamellar spacingdincreases with enthalpic repulsion between the two blocks as well as the molecular weight of the diblock ring. The scaling argument fordof diblock linear polymers is modified by accounting for the globular conformations and predicts well the dependencies ofdon the enthalpic repulsion and molecular weight. The lamellar interface becomes sharper as the enthalpic repulsion increases. While the theory predicts that the intrinsic interfacial width does not depend on the polymer molecular weight or topology, the apparent interfacial widthw, which is broadened by the capillary wave, exhibits slight variation with the molecular weight and topology.
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DOI：
10.1002/polb.10672
发表时间：
2004-01
期刊：
Journal of Polymer Science Part B
影响因子：
--
作者：
S. Sides;G. Grest;M. Stevens;S. Plimpton
通讯作者：
S. Sides;G. Grest;M. Stevens;S. Plimpton
聚合物/聚合物界面统计结构的散射
影响因子：
5.5
作者：
A. Semenov
通讯作者：
A. Semenov
影响因子：
1.8
作者：
M. Murat;G. Grest;K. Kremer
通讯作者：
K. Kremer
影响因子：
8.6
作者：
A. Rosa;R. Everaers
通讯作者：
A. Rosa;R. Everaers
影响因子：
41.2
作者：
Kapnistos M;Lang M;Vlassopoulos D;Pyckhout-Hintzen W;Richter D;Cho D;Chang T;Rubinstein M
通讯作者：
Rubinstein M