As 5G communication develops rapidly, the traditional interlayer insulating dielectric material polyimide (PI) can no longer meet the requirements of large-scale integrated circuits, high-velocity, high-frequency communication, and other microelectronic applications, and urgently needs modification. In this paper, we superimpose the modification effects of bulk triphenyl pyridine structure and ester group structure and combine the bulk and low polarizability groups to successfully prepare a new type of PI with a low dielectric constant (D_k) and low dielectric loss (D_f) at high frequency. The research focuses on the structure–property correlation of PIs, especially the effect of fluorine content on the dielectric properties. Firstly, three bulk diamine monomers (BPAB, PBAB3F, PBAB6F) containing a triphenyl pyridine structure were designed and synthesized, which were then polymerized with the 2,2-propenylidene-4,1-phenylene-1,3-dihydro-1,3-dioxo-5-isobenzofuran carboxylic acid ester (BTPDA) to obtain three new PIs with different fluorine contents (PI-EH, PI-ECF₃, PI-E2CF₃, respectively). Testing results show that the dielectric properties and moisture absorption of the PIs are improved with increased fluorine content. The new PIs showed excellent properties, such as low dielectric constants (D_k = 2.84–2.74 @ 10 GHz and D_f = 0.00373–0.00338 @ 10 GHz), low water absorption (0.94–0.73%), and high hydrophobicity (contact angle = 77–97°), with PI-E2CF₃ having the best overall performance. The present study was carried out to provide a reference for preparing high-frequency, low dielectric constant, and low-loss interlayer dielectric materials.

The rapid development of electronic devices with high integration levels, a light weight, and a multifunctional performance has fostered the design of novel polymer materials with low dielectric constants, which is crucial for the electronic packaging and encapsulation of these electronic components. Theoretical studies are more efficient and cost-effective for screening potential polymer materials with low dielectric constants than experimental investigations. In this study, we used a molecular density functional theory (DFT) approach combined with the B3LYP functional at the 6-31+G(d, p) basis set to validate the feasibility of predicting static dielectric constants of the polymer materials. First, we assessed the influence of the basis sets on the polarizability. Furthermore, the changes of polarizability, polarizability per monomer unit, and differences in polarizability between the consecutive polymer chains as a function of the number of monomers were summarized and discussed. We outlined a similar behavior for the volume of the polymers as well. Finally, we simulated dielectric constants of three typical polymer materials, polyethylene (PE), polytetrafluoroethylene (PTFE), and polystyrene (PS), by combining with the Clausius–Mossotti equation. The simulated results showed excellent agreement with experimental data from the literature, suggesting that this theoretical DFT method has great potential for the molecular design and development of novel polymer materials with low dielectric constants.