Gels formed by coupling two different four-arm star polymers lead to polymer networks with high strength and low spatial heterogeneity. However, like all real polymer networks, these materials contain topological defects which affect their properties. In this study, kinetic graph theory and Monte Carlo simulation are used to investigate the structure and cyclic defects formed via A–B type end-linking of symmetric tetra-arm star polymer precursors. While loops constituting of odd number of junctions are forbidden by precursor chemistry, the amount and the correlation of secondary loops are found to increase with decreasing precursor concentration. This suppresses gelation, and the delay of gel point is quantitatively predicted by the topological simulations. Furthermore, comparison with network formed with asymmetric bifunctional–tetrafunctional precursors revealed that the behavior of loops consisting of 2n junctions in the symmetric system is analogous to the behavior of loops consisting of n junctions in the asymmetrical system, suggesting analogies between chemically distinct networks.

中文翻译：

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由对称四臂前驱物形成的网络的拓扑结构

通过偶联两种不同的四臂星形聚合物形成的凝胶导致聚合物网络具有高强度和低空间异质性。但是，像所有实际的聚合物网络一样，这些材料包含影响其性能的拓扑缺陷。在这项研究中，动力学图论和蒙特卡洛模拟被用来研究通过对称四臂星形聚合物前体的A–B型端键形成的结构和循环缺陷。尽管前体化学禁止构成奇数个结的环，但是发现次级环的数量和相关性会随着前体浓度的降低而增加。这抑制了凝胶化，并且通过拓扑模拟定量预测了凝胶点的延迟。此外，对称系统中的n个结类似于非对称系统中n个结组成的环的行为，这表明化学上不同的网络之间存在类比。