The main challenge to developing future display substrates is to synthesize flexible substrate materials that also have excellent optical and thermal properties, and low thermal expansion number. In this study, a novel trifluoromethylated asymmetric aromatic diamine, 4-[[4-(4-amino-2-trifluoromethylphenoxy)phenyl]sulfonyl-3-(trifluoromethyl)]benzenamine (AFPSFB), was synthesized through nucleophilic substitution. Conventional two-step polycondensation of AFPSFB with commercially available tetracarboxylic dianhydrides enabled the fabrication of fully or semi-aromatic polyimides (PIs). The resulting PIs were highly soluble in polar aprotic solvents with good optical and thermal properties. Next, polyhedral oligomeric silsesquioxane containing an amine group (NH2-POSS) was reacted with the resulting soluble PI. All the PI-POSS nanohybrids displayed excellent optical properties, including high transparency (>91% at 400 nm), low refractive index (<1.5589), and very small birefringence (<0.0025 at 637 nm). End-capping of the POSS and chemical bonding between the POSS and PIs significantly enhanced the thermal and electrical properties. The results provide useful information for designing molecular architectures for manufacturing high-performance flexible substrates in future display devices.
Bibliographical noteFunding Information:
This work was supported by a grant from the Korea Institute of Science and Technology (KIST) Institutional Program & Open Research Program and the Nano Material Technology Development Program through the National Research Foundation (NRF) of Korea funded by the Ministry of Science, ICT and Industrial Fundamental Technology Development Program ( 10052838 ) by the Ministry of Trade, Industry and Energy (MOTIE) of Korea and Space Core Technology Development Program through the National Research Foundation of Korea funded by the Ministry of Science, ICT and Future Planning ( NRF-2017M1A3A3A02016310 ).
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Mechanics of Materials
- Mechanical Engineering
- Industrial and Manufacturing Engineering