STUDY ON THE LB FILMS OF A HAIRY-ROD LADDER POLYSILSESQUIOXANE WITH TRIPHENYLENE SIDE GROUPS

A novel kind of "hairy-rod" ladder polysilsesquioxane (LPSQ) with alkyl substituted triphenylene side groups formed a stable monolayer on the air-water interface, and the effects of temperature, solvents and concentration of LPSQ solution on pi-A isotherm curves were investigated. The monolayers of LPSQ can be successfully transferred onto hydrophobic surface of silicon wafer or quartz plate to develop a very stable and uniform Y-type Langmuir-Blodgett (LB) film when using toluene as the spreading solvent at proper surface pressure. High stability of LPSQ LB films is confirmed by the fact that the intensity of UV absorption does not decay within several months and AFM image shows uniform and compact films without noticeable defects. The in-plane anisotropy was monitored by the combination of polarized UV and fluorescence spectroscopy, revealing that the backbones of LPSQ adopted a preferential orientation parallel to the dipping direction with an optimum orientation parameter S of 0.42. Furthermore,the stable and uniform LB films of LPSQ with the triphenylene side groups promise to be a fine one-dimensional molecular/nano-wire material.