HIGHLY ORIENTED POLYSILANE FILMS PREPARED BY THE LANGMUIR-BLODGETT TECHNIQUE

Highly oriented polysilane thin films were provided by the Langmuir-Blodgett technique. All polysilanes bearing phenol moieties provided monolayers on the air/water interface and were transferred to a substrate step by step. Among these polysilanes, only poly((3-hydroxyphenyl)n-butyl)silane provided thin films oriented parallel to the dipping direction of the substrate. The orientation was evaluated by polarized UV absorption and polarized fluorescence spectroscopy. The order parameter reached 0.5, which corresponded to those of conventional nematic liquid crystals. Order parameters were independent of the excitation wavelengths, whose feature was distinct from that in a solution. This suggests that fast and efficient energy migrations take place along the Si-Si main chains.