Ma Rui, Baldwin Aaron F, Wang Chenchen, Offenbach Ido, Cakmak Mukerrem, Ramprasad Rampi, Sotzing Gregory A
Polymer Program, University of Connecticut , 97 North Eagleville Road, Storrs, Connecticut 06269, United States.
ACS Appl Mater Interfaces. 2014 Jul 9;6(13):10445-51. doi: 10.1021/am502002v. Epub 2014 Jun 24.
Development of new dielectric materials is of great importance for a wide range of applications for modern electronics and electrical power systems. The state-of-the-art polymer dielectric is a biaxially oriented polypropylene (BOPP) film having a maximal energy density of 5 J/cm(3) and a high breakdown field of 700 MV/m, but with a limited dielectric constant (∼2.2) and a reduced breakdown strength above 85 °C. Great effort has been put into exploring other materials to fulfill the demand of continuous miniaturization and improved functionality. In this work, a series of polyimides were investigated as potential polymer materials for this application. Polyimide with high dielectric constants of up to 7.8 that exhibits low dissipation factors (<1%) and high energy density around 15 J/cm(3), which is 3 times that of BOPP, was prepared. Our syntheses were guided by high-throughput density functional theory calculations for rational design in terms of a high dielectric constant and band gap. Correlations of experimental and theoretical results through judicious variations of polyimide structures allowed for a clear demonstration of the relationship between chemical functionalities and dielectric properties.
新型介电材料的开发对于现代电子和电力系统的广泛应用至关重要。目前最先进的聚合物电介质是双轴取向聚丙烯（BOPP）薄膜，其最大能量密度为5 J/cm³，高击穿场强为700 MV/m，但介电常数有限（约2.2），且在85°C以上击穿强度会降低。人们付出了巨大努力来探索其他材料，以满足持续小型化和功能改进的需求。在这项工作中，研究了一系列聚酰亚胺作为该应用的潜在聚合物材料。制备出了介电常数高达7.8、损耗因子低（<1%）且能量密度高约15 J/cm³的聚酰亚胺，这是BOPP的3倍。我们的合成是在高通量密度泛函理论计算的指导下进行的，以便在高介电常数和带隙方面进行合理设计。通过对聚酰亚胺结构进行明智的变化，实验结果与理论结果的相关性清晰地展示了化学官能团与介电性能之间的关系。
