Synthesis of soluble and autophotosensitive hyperbranched polyimides with good optical properties and thermal properties

A series of autophotosensitive hyperbranched polyimides based on a new triamine, 1,3,5-tri(3-aminophenoxy-4′-benzoyl)benzene (TABB), various aromatic dianhydride monomers, and endcapped with ortho-alkyl aniline was synthesized by two-step chemical imidization methods. UV–vis spectra indicated high optical transparency of the hyperbranched polymer (HBPI) films with a UV–vis absorption edge of 342–353 nm. The spin-coated films of HBPIs presented a minimum birefringence value as low as 0.0026 at 650 nm and low dielectric constants of 2.74–3.09 (at 1 MHz). The HBPI films also showed high glass-transition temperatures between 190 and 238 °C, good thermal stabilities with 5 wt % loss temperatures ranged from 506 to 525 °C and excellent organosolubilities even in acetone and chloroform. Photolithographic property of the polymer was examined by UV exposure. SEM analysis revealed that highly resolved pattern with a line width of 20 µm were obtained.