Syntheses and sol-gel polymerizations of organotriethoxysilanes

The main aim of the present research was to synthesize a macromolecular hybrid porous structure which could effectively be applied as a membrane. To achieve this goal, a model oligomer system was first synthesized containing a flexible silsesquioxane side chain and based on a rigid phenylene ethynylene backbone. The rate of gelation of both the silsesquioxanes was found to be very high and proportional to the acid concentration. The rigid organic backbone of the organotriethoxysilanes was successfully removed by converting the carbamate to primary amine through LiAlH4 treatment, as evidenced by infrared spectroscopy.;Based on similar lines, polymers containing rigid phenylene ethynylene backbone were synthesized having different silsesquioxane unit concentration in the repeating unit. In spite of the long and flexible oligoether and silsesquioxane side chains of the monomers, all the resulting polymers had poor solubility in most organic solvents, making further processing impossible.