Synthesis and properties of highly organosoluble and low dielectric constant polyimides containing non-polar bulky triphenyl methane moiety

Novel fluorinated aromatic polyimides were prepared by the conventional two-step imidization of 4.4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) and diamines (TriPMPDA and TriPMMDA) bearing triphenyl methane moiety. Both of the flexible and tough polyimide films exhibited an intrinsic low dielectric constant (low-k) values of 2.56 and 2.33 at the frequency of 10 kHz, respectively, due to the introduction of the bulky triphenyl methane side groups and the tortuous backbone structures. In addition, they showed light color, high thermal stability, moderate mechanical property, and more importantly, excellent solubility in common organic solvents (even completely dissolved in dichloromethane and chloroform). Thus, both of the functional polyimides possessed attractive potential applications in the field of high performance flexible polymer interlayer materials.