Production of PI/PTFE@PI nanocomposite membrane for dielectric material using electrospinning and dipping coating methods

The development of advanced dielectric materials is integral to improving the performance of high-frequency telecommunication devices. Developing composite membranes that effectively balance superior dielectric properties, high thermal stability, mechanical strength, and other key characteristics for practical applications remains a significant challenge. This study presents the fabrication of a nanocomposite membrane, combining polyimide (PI) and polytetrafluoroethylene (PTFE) within a PI matrix, designed for dielectric applications. The PI/PTFE@PI nanocomposite membranes were fabricated through electrospinning and dip-coating techniques. These membranes exhibited dielectric constants between 1.64 and 1.99 at 10 GHz, accompanied by a low dielectric loss, ranging from 0.001 to 0.009. Dielectric breakdown strengths varied between 108.38 and 169.44 kV/mm. Mechanical properties included a tensile strength of 26.81 MPa and a Young's modulus of 858 MPa. Thermal stability tests showed a maximum thermal degradation temperature ( T max ) of 659 °C and a 5% weight loss temperature ( T d5% ) of 450 °C for pure PI composite membranes. The PI/PTFE@PI-40% composite membrane demonstrated a water contact angle of 110.8° and a water absorption rate of 0.5%, indicating its suitability as a potential dielectric material for telecommunication applications.