Fluorinated Hyperbranched Polyimide for Optical Waveguides

A novel fluorinated hyperbranched polyimide (HBPI) is synthesized by using a new triamine monomer, 1,3,5‐tris(2‐trifluoromethyl‐4‐aminophenoxy)benzene (TFAPOB) (A3), as a ‘core’ molecule, 4,4‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA) as a B2 monomer, and 3,5‐ditrifuoromethylphenyl as an endcapping reagent. The polymer shows a glass transition temperature of 232 °C and a temperature of 10% weight loss at 535 °C. The HBPI presents a birefringence as low as 0.002 at 650 nm. Near‐IR results indicate that HBPI exhibits desirable properties for low loss optical waveguide applications. magnified image