Fluorinated polyimides (PIs) with low dielectric constant (ε) have attracted increasing attention with the rapid development of advanced power electronics and 5G communication. In this work, the dielectric constants of three types of fluorinated PIs are firstly predicted by using two “Group contribution” methods, the Clausius-Mossotti method and the molecular dynamics (MD) simulation. The most reasonably good agreement is found between the MD simulated values and the previously reported experimental data. Secondly, the so-called “fluorine impact” from fluorine content (F%), molecular polarization (α/V), fractional free volume (FFV) and PI/water interaction energy (E_inter) caused by the fluorine substituents on dielectric constant of the PIs are investigated. The substitution position and structure of the fluorine moieties demonstrate pronounced influence on dielectric constant when the PIs have similar fluorine content. Finally, the weight of each factor obtained by principal component analysis (PCA) is applied to assess an overall evaluation of the “fluorine impact”. α/V and F% are revealed to be the dominant factors to affect the dielectric constant. Based on the studied PI systems, a “negative” fluorine impact was attributed by a high α/V value. It can be speculated that the structure of PI-b1 provides an ideal pattern for designing new low-ε polyimides, i.e., increasing the amount of rigid di-substituted symmetric fluorine side chains with low molecular polarity in PI backbones.

随着先进电力电子技术和 5G 通信的快速发展，具有低介电常数 (ε) 的氟化聚酰亚胺 (PI) 引起了越来越多的关注。在这项工作中，首先使用克劳修斯-莫索蒂方法和分子动力学（MD）模拟两种“基团贡献”方法来预测三种氟化 PI 的介电常数。在 MD 模拟值和先前报告的实验数据之间发现了最合理的良好一致性。其次，从氟含量（F%）、分子极化（α/V）、自由体积分数（FFV）和PI/水相互作用能（E _inter) 研究了氟取代基对 PI 介电常数的影响。当 PI 具有相似的氟含量时，氟部分的取代位置和结构对介电常数有显着影响。最后，通过主成分分析（PCA）获得的每个因素的权重，用于评估“氟影响”的整体评价。α/V 和 F% 是影响介电常数的主要因素。基于所研究的 PI 系统，“负”氟影响归因于高 α/V 值。可以推测PI-b1的结构为设计新的低ε聚酰亚胺提供了一种理想的模式，即增加PI主链中具有低分子极性的刚性二取代对称氟侧链的数量。