Hot-pressed CAU-10-H/PEEK composite films with robust thermal stability and moisture resistance for high-frequency low-dielectric applications

Permittivity is a key parameter characterising the polarisation capacity of a dielectric, and directly influences a material’s signal transmission and energy storage properties. As electronic devices evolve towards higher frequencies and greater integration, there is an increasing demand for polymer materials that combine low dielectric constant with excellent thermal and environmental stability. In this study, a aluminium-based metal-organic framework material CAU-10-H, which exhibits negative thermal expansion, was synthesised using the hydrothermal method and incorporated into PEEK matrix by hot-press to prepare CAU-10-H/PEEK composite films. The as-obtained CAU-10-H is relatively well dispersed within the PEEK matrix at low-to-moderate filler loadings, while its incorporation is associated with a reduction in the dielectric constant of the composite. The reduced dielectric response is mainly attributed to the introduction of low-polarity nanoporous domains, while the increase in free volume fraction may also contribute to this behaviour. When the filler content is 5 wt%, the composite exhibits a low die This may be attributed to the following factors:lectric constant across the 2–18 GHz frequency range, with an average value as low as 2.45, whilst the thermal decomposition temperature is above 500℃. In addition, this composite material offers moisture resistance, excellent dimensional stability, outstanding frequency stability and good signal integrity. This study provides new insights into the regulation of the high-frequency dielectric properties and stability of polymer composites using microporous materials with negative thermal expansion characteristics. Download: Download high-res image (181KB) Download: Download full-size image Owing to the inherent microporous structure of MOFs and their interaction with the polymer matrix, this composite material achieves a dual reduction in both the dielectric constant and dielectric loss at high frequencies, whilst exhibiting excellent thermal stability and superior moisture resistance.