Low dielectric constant and ultra-low dielectric loss poly(arylene ether nitrile)/octaphenyl-POSS composite films with dual cross-linked networks

The continuous progress of microelectronic technology requires polymer materials with low dielectric constant, low dielectric loss, excellent mechanical properties and heat stability. As an emerging advanced polymer, poly(arylene ether nitrile) has shown great potential in the field of microelectronics. However, there is still a need to decrease its inherent dielectric constant and dielectric loss. In this work, the cross-linked poly(arylene ether nitrile) containing propenyl and trifluoromethyl groups (PEN) was designed and synthesized. Then the cage-like structure of octaphenyl polyhedral oligomeric silsesquioxane (OPOSS) was introduced to prepare the composite membranes by solution-casting method. After undergoing thermal treatment, dual cross-linked networks were formed, with OPOSS securely embedded within them. The results show that the composite films exhibit significantly enhanced heat stability (T 5%  ≥ 491 °C), tensile strength (≥72 MPa) and remain great hydrophobicity (106.6–114.2°). More importantly, among all the composite films, the dielectric constant and dielectric loss of the CPEN/OPOSS-8 composite film are as low as 2.19 and 0.0025 at 1 MHz, respectively. Such excellent comprehensive performance, especially in low dielectric constant while obtaining ultra-low dielectric loss, will make it possible to be used as a low dielectric material. This strategy will open up a new way of thinking for the development of low dielectric materials.