Periodic molecular dynamics simulations are developing to a routine tool for the investigation of complex, polymeric materials. A typical application is the simulation of the curing reaction of covalently cross-linked polymers, which provides detailed understanding of network formation at the molecular scale, with examples including gelation and glass transitions. In this article, we delineate the connection between percolation theory and gel-point detection in periodic polymeric networks. Specifically, we present an algorithm that can detect the onset of percolation during cross-linking of polymers in periodic molecular dynamic simulations. A sample implementation is provided at https://github.com/puls-group/percolation-analyzer. As an example, we apply the algorithm to simulations of an epoxy resin undergoing curing with an amine hardener. We also compare results with indirect gel point measurements obtained from monitoring the growth of the largest mass and the onset of secondary cycles.

中文翻译：

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在交联聚合物网络的分子动力学模拟中检测渗透转变的精确算法

周期性分子动力学模拟正在发展成为研究复杂聚合物材料的常规工具。一个典型的应用是模拟共价交联聚合物的固化反应，它提供了对分子尺度网络形成的详细理解，示例包括凝胶化和玻璃化转变。在本文中，我们描述了渗透理论与周期性聚合物网络中的凝胶点检测之间的联系。具体来说，我们提出了一种算法，可以在周期性分子动力学模拟中检测聚合物交联过程中渗透的开始。https://github.com/puls-group/percolation-analyzer 提供了示例实现。例如，我们将该算法应用于模拟环氧树脂与胺固化剂固化的过程。