Chain-end-mediated interfacial design of transparent and hydrophobic PI/SiO2 films

Highly transparent and hydrophobic polyimide (PI) films are attractive for advanced optoelectronic and flexible electronic devices, but their performance is often limited by weak organic–inorganic interactions and nanoparticle aggregation. In this work, a chain-end-mediated interfacial design was developed by combining IPTS-mediated PI/SiO 2 coupling with subsequent PFOTES surface fluorination. This sequential interface/surface regulation provided a practical route to jointly improve transparency, hydrophobicity, and thermo-mechanical performance in PI nanocomposite films. The optimized PI-Z2F film exhibited a transmittance at 500 nm (T₅₀₀) of 90.6%, a water contact angle of 114°, a glass-transition temperature (Tg) of 326 °C, and a tensile strength of 165 MPa. These results indicate that coordinated interfacial construction and surface fluorination provide an effective route to balancing hydrophobicity, optical transparency, and thermo-mechanical performance in PI nanocomposite films.