Cui Kunqi, Wang Yang, Yan Wenchao, Cao Teng, Du Yan, Wu Kai, Guo Li
School of Electronics and Information, Xi'an Polytechnic University, Xi'an 710048, China.
Xi'an Key Laboratory of Interconnected Sensing and Intelligent Diagnosis for Electrical Equipment, Xi'an Polytechnic University, Xi'an 710048, China.
Molecules. 2025 Jul 14;30(14):2960. doi: 10.3390/molecules30142960.
As a key insulating material in power equipment, epoxy resins (EP) are often limited in practical applications due to space charge accumulation and mechanical degradation. This study systematically investigates the effects of SiO nanoparticle doping on the electrical and mechanical properties of SiO/EP composites through molecular dynamics simulations and first-principles calculations. The results demonstrate that SiO doping enhances the mechanical properties of EP, with notable improvements in Young's modulus, bulk modulus, and shear modulus, while maintaining excellent thermal stability across different temperatures. Further investigations reveal that SiO doping effectively modulates the interfacial charge behavior between EP and metals (Cu/Fe) by introducing shallow defect states and reconstructing interfacial dipoles. Density of states analysis indicates the formation of localized defect states at the interface in doped systems, which dominate the defect-assisted hopping mechanism for charge transport and suppress space charge accumulation. Potential distribution calculations show that doping reduces the average potential of EP (1 eV for Cu layer and 1.09 eV for Fe layer) while simultaneously influencing the potential distribution near the polymer-metal interface, thereby optimizing the interfacial charge injection barrier. Specifically, the hole barrier at the maximum valence band (VBM) after doping significantly increased, rising from the initial values of 0.448 eV (Cu interface) and 0.349 eV (Fe interface) to 104.02% and 209.46%, respectively. These findings provide a theoretical foundation for designing high-performance epoxy-based composites with both enhanced mechanical properties and controllable interfacial charge behavior.
作为电力设备中的关键绝缘材料，环氧树脂（EP）由于空间电荷积累和机械降解，在实际应用中常常受到限制。本研究通过分子动力学模拟和第一性原理计算，系统地研究了SiO纳米颗粒掺杂对SiO/EP复合材料电学和力学性能的影响。结果表明，SiO掺杂增强了EP的力学性能，杨氏模量、体积模量和剪切模量均有显著提高，同时在不同温度下保持了优异的热稳定性。进一步研究表明，SiO掺杂通过引入浅缺陷态和重构界面偶极子，有效地调节了EP与金属（Cu/Fe）之间的界面电荷行为。态密度分析表明，在掺杂体系的界面处形成了局域缺陷态，其主导了电荷输运的缺陷辅助跳跃机制，并抑制了空间电荷积累。电位分布计算表明，掺杂降低了EP的平均电位（Cu层为1 eV，Fe层为1.09 eV），同时影响了聚合物-金属界面附近的电位分布，从而优化了界面电荷注入势垒。具体而言，掺杂后最高价带（VBM）处的空穴势垒显著增加，分别从初始值0.448 eV（Cu界面）和0.349 eV（Fe界面）上升到104.02%和209.46%。这些发现为设计具有增强力学性能和可控界面电荷行为的高性能环氧基复合材料提供了理论基础。
