Soluble and colorless polythioetherimide films hybridized by TiO2/ZrO2 particles

Colorless polyimides (CPIs) have emerged as crucial substrate materials for OLED displays. Polythioetherimide (PTEI) materials with sulfur atoms, demonstrate superior optical property, thermal stability and solubility compared with conventional polyimides. In this work, two types of soluble PTEI films were synthesized via a thiol-ene click reaction. By adjusting the molar ratio of titanium or zirconium n-butoxide to PTEIs, two series of PTEI-based nanohybrid films (PTEIs-Ti-X% and PTEIs-Zr-X%) were fabricated with 4–12 wt% of TiO 2 or ZrO 2 . SEM and XRD analyses confirmed homogeneous dispersion of the inorganic components. The hybrid films exhibited high thermal stability, with 5 % weight loss temperatures (Td 5 ) reaching 342 °C and 331 °C, and glass transition temperatures (T g ) ranged between 189–225 °C and 184–229 °C for the Ti- and Zr-containing hybrids, respectively. They both displayed low thermal expansion coefficients (CTE), indicating outstanding dimensional stability. Optically, the refractive index at 633 nm could be tuned from 1.6920 to 1.7341 for Ti hybrids and from 1.6867 to 1.7247 for Zr hybrids. Transparency measurements at 450 nm remained above 75 % for Ti-based films and reached up to 89 % for Zr-based films. Overall, PTEI hybrid films exhibit a well-balanced combination of properties for high-performance optical and display applications