• polyimides;
  • haloid pendants;
  • tunable refractive index


To investigate the difference of trifluoromethyl group and chlorine group affecting the optical properties of polyimides (PIs), two diamine monomers with different haloid pendants were designed and synthesized including (1,4-(4-amino-2-trifluoromethylphenoxy)-2-(3′5′-ditrifluoromethylphenyl)benzene and (1,4-(4-amino-2-trifluoromethylphenoxy)-2-(3′-trifluoromethyl-4′-chlorophenyl) benzene). From both diamines, two series of PIs with different haloid pendants were prepared via two-step chemical imidization methods with various dianhydride compounds. All the PIs have the high Tg, excellent thermal stability and good solubility, and can be formed the transparent, strong, and flexible films. All the PIs also are good transparent in UV-evisible absorption spectra, and have the low birefringences (0.0128–0.0157 at 650 nm) and low optical loss at communication windows. Two series of PIs exhibit the similar optical properties, except for refractive index. Based on the fantastic characterization, a series of optical materials with the tunable refractive indices were obtained by copolymerization. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011