Intelligent cross-linking in polymer simulations: SuSi’s approach to complex 3D networks

Cross-linked polymers play a vital role in the materials science due to their mechanical strength, chemical resistance, and thermal stability, making them invaluable in biomedical devices, coatings, and electronics. However, constructing realistic molecular models of these systems remains a challenge due to their complex cross-linked networks. This study introduces SuSi, a Python-based program designed to generate both linear and cross-linked polymer systems for molecular simulations. SuSi uses artificial intelligence tree search algorithms to optimize the cross-linking process, ensuring efficient and collision-free network formation. The program is compatible with the AMBER force field and supports a wide variety of polymer architectures, including homopolymers, block copolymers, and complex 3D-network structures. To demonstrate its capabilities, SuSi was employed to generate three distinct cross-linked systems: silane-cross-linked polyethylene (Si-XLPE), thermosensitive poly(NIPAAm-co-MBA), and the complex unsaturated polyesteramide hydrogel made of phenylalanine, butenediol, and fumarate, cross-linked with polyethylene glycol (UPEA-PEG). The generated structures were successfully parametrized for molecular dynamics simulations and validated through experimental observables, showing that SuSi is a versatile tool for accurately modeling complex polymeric systems and advancing polymer simulations.

交联聚合物凭借其优异的机械强度、耐化学腐蚀性与热稳定性，在材料科学领域发挥着至关重要的作用，因此在生物医学装置、涂料及电子器件中拥有不可替代的应用价值。然而，由于这类材料拥有复杂的交联网络结构，构建其真实可靠的分子模型仍是一项挑战。本研究推出了一款基于Python开发的程序SuSi，专为分子模拟场景构建线性与交联聚合物体系。SuSi采用人工智能树搜索算法对交联过程进行优化，确保网络形成过程高效且无碰撞干扰。该程序兼容AMBER力场，可支持多种聚合物结构类型，包括均聚物、嵌段共聚物以及复杂的三维网络结构。为验证其性能，研究团队利用SuSi构建了三类不同的交联聚合物体系：硅烷交联聚乙烯（silane-cross-linked polyethylene, Si-XLPE）、温敏型聚(NIPAAm-co-MBA)，以及由苯丙氨酸、丁烯二醇与富马酸酯制备、经聚乙二醇交联的复杂不饱和聚酯酰胺水凝胶（unsaturated polyesteramide hydrogel cross-linked with polyethylene glycol, UPEA-PEG）。所构建的结构已成功完成分子动力学模拟的参数化工作，并通过实验观测数据得到验证，证明SuSi是一款可用于精准建模复杂聚合物体系、推动聚合物模拟研究发展的多功能工具。