High-frequency low-dielectric-loss in linear-backbone-structured polyimides with ester groups and ether bonds
Chenggang Zhang, Xiaojie He, Qinghua Lu
Abstract
Abstract Polyimides have emerged as promising dielectric materials for communication equipment, owing to their excellent thermal stability and processability. Nonetheless, a pressing need remains to reduce the high-frequency dissipation factor ( D f ) of polyimides. Here, we synthesized various polyimides featuring linear backbone structures, finding that polyimides that incorporate a combination of ester groups and ether bonds exhibit low D f values of 0.0015-0.0024 at 10 GHz. Even in high humidity and temperature conditions they maintain low D f values of <0.005 at 10 GHz. To gain insight into the factors influencing this behavior, we conduct a comprehensive study involving aggregation structures and hygroscopic properties. Our findings highlight the pivotal role of high orientation and crystallinity in determining the high-frequency D f of polyimide films.