Micro-crosslinked polyimide nanocomposites with low dielectric constant and low dielectric loss for microwave antenna with molecular dynamics

Low dielectric polyimide (PI) is a crucial component of interlayer dielectric materials in modern electronic devices, which effectively mitigates signal delay and power loss issues arising from the high integration. Herein, low dielectric nanocomposite with micro-crosslinked structure is prepared through in-situ polymerization of fluorinated PI (f-PI) and polyhedral oligomeric silsesquioxane (POSS). Four f-PIs with different positions of trifluoromethyl and structure of backbone, and three functionalized POSS are studied by density functional theory (DFT) and classical molecular dynamics (MD) simulations to reveal the effects of the PI structure and the interfacial interaction of POSS with PI on dielelectric constant. Specifically, the dielectric constant and dielectric loss of 3 wt% 8NH2-POSS/PI1 at 1 kHz are reduced to 2.40 and 0.0017, respectively. The micro-crosslinked structure provides better thermal stability (513.3 °C), coefficient of thermal expansion (42.14 ppm °C−1), and acid resistance, meeting the requirements of integrated circuits (ICs) processing. In comparison to commercial epoxy boards (FR4), the 3 wt% 8NH2-POSS/PI exhibits lower S11 signal loss (−10.874 dB) and provides greater magnetic fields (2.00 G) near 3.0 GHz as the substrate of Nitrogen-Vacancy (NV) centers sensor. This well-performing low dielectric nanocomposite offers a promising medium for ICs.