TiO2‐Functionalized Sulphur Containing Polyimides for Optical Applications

Summary: Novel sulphur‐containing 6FDA‐SDA‐DABA (4,4'‐(hexafluoroisopropylidene)diphthalic anhydride – 4,4'‐diaminodiphenylether – 3,5‐diaminobenzoic acid) copolyimides have been synthesized to create a polymer basis for the use as optical polymers, capable of implementing TiO2 nanoparticles by simple mixing or covalent bonding of functionalized nanoparticles. First fine dispersed nanoparticle‐composites were made by simple mixing of rutile‐type TiO2 nanoparticles and the synthesized copolyimides. Moisture‐absorption was measured in a climate‐cabinet, transparency and cutoff wavelengths have been determined by UV‐VIS spectra. The homogeneity of the composites was verified by scanning electron microscope (SEM) images of the cross sections. The polyimides show constantly low water sorption below 0.08 wt% and cutoff wavelengths below 440 nm. The implementation of nanoparticles by simple mixing was verified by SEM.