Herein, the coupling relationship between molecule structure and ion conductivity in silica filled silicone gel are established. Based on the broadband dielectric spectrum, the concentration of ion charges and ions diffusion coefficients, two key roles for ion conductivity, are calculated. The concentration of ion charges is increased by about four orders of magnitude after the addition of silica. Because of the more short-length chains conformations and more amorphous regions at interfaces, the chains at interfaces are easier to rearrange with higher relaxation frequency, which enhances the ions diffusion process and contributes to negative decoupling exponents between the interface molecule relaxations and ion diffusion coefficients in silicone gel composites. With the increase of fumed silica loading, the ionic conductivity increases first and decreases owing to percolation phenomenon about silica dispersion. Meanwhile, decoupling exponents of the interface molecules are closer to 0. Our findings deepen the understanding how the interface structures act on ions conductivity in insulating polymer composites, which is critical to rationally design interface structures for manipulating the insulation performances.

中文翻译：

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二氧化硅/硅凝胶界面分子结构与聚合物复合材料离子电导率的耦合关系

在此，建立了二氧化硅填充硅胶中分子结构和离子电导率之间的耦合关系。基于宽带介电谱，计算离子电荷浓度和离子扩散系数（离子电导率的两个关键作用）。添加二氧化硅后离子电荷浓度增加约四个数量级。由于界面处有更多的短链构象和更多的非晶区，界面处的链更容易以更高的弛豫频率重排，这增强了离子扩散过程，并有助于界面分子弛豫和离子扩散系数之间的负解耦指数在有机硅凝胶复合材料中。随着气相二氧化硅负载量的增加，由于二氧化硅分散体的渗流现象，离子电导率先增加后减小。同时，界面分子的解耦指数更接近0。我们的研究结果加深了人们对界面结构如何影响绝缘聚合物复合材料中离子电导率的理解，这对于合理设计界面结构以控制绝缘性能至关重要。